add simple quote message context menu

add hacky way to load encrypted tox saves
limit fps to 60 and disable imgui demo window
2023-09-01 21:13:36 +02:00 · 2023-08-28 15:33:36 +02:00 · 2023-08-28 14:06:27 +02:00 · 2023-08-20 12:50:58 +02:00 · 2023-08-19 21:42:47 +02:00 · 2023-08-12 20:17:29 +02:00
1017 changed files with 227763 additions and 17124 deletions
--- a/README.md
+++ b/README.md
@@ -0,0 +1,4 @@
+# Tomato
+
+![tomato](res/icon/tomato_v1_256.png)
+
--- a/external/CMakeLists.txt
+++ b/external/CMakeLists.txt
@@ -15,3 +15,6 @@ add_subdirectory(./solanaceae_tox)
 add_subdirectory(./sdl)
 add_subdirectory(./imgui)

+add_subdirectory(./stb)
+add_subdirectory(./libwebp)
+
--- a/external/libwebp/CMakeLists.txt
+++ b/external/libwebp/CMakeLists.txt
@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.9 FATAL_ERROR)
+
+set(WEBP_LINK_STATIC ON CACHE INTERNAL "")
+
+add_subdirectory(./libwebp EXCLUDE_FROM_ALL)
+
--- a/external/libwebp/libwebp/.cmake-format.py
+++ b/external/libwebp/libwebp/.cmake-format.py
@@ -0,0 +1,240 @@
+# ----------------------------------
+# Options affecting listfile parsing
+# ----------------------------------
+with section("parse"):
+
+  # Specify structure for custom cmake functions
+  additional_commands = { 'foo': { 'flags': ['BAR', 'BAZ'],
+             'kwargs': {'DEPENDS': '*', 'HEADERS': '*', 'SOURCES': '*'}}}
+
+  # Override configurations per-command where available
+  override_spec = {}
+
+  # Specify variable tags.
+  vartags = []
+
+  # Specify property tags.
+  proptags = []
+
+# -----------------------------
+# Options affecting formatting.
+# -----------------------------
+with section("format"):
+
+  # Disable formatting entirely, making cmake-format a no-op
+  disable = False
+
+  # How wide to allow formatted cmake files
+  line_width = 80
+
+  # How many spaces to tab for indent
+  tab_size = 2
+
+  # If true, lines are indented using tab characters (utf-8 0x09) instead of
+  # <tab_size> space characters (utf-8 0x20). In cases where the layout would
+  # require a fractional tab character, the behavior of the  fractional
+  # indentation is governed by <fractional_tab_policy>
+  use_tabchars = False
+
+  # If <use_tabchars> is True, then the value of this variable indicates how
+  # fractional indentions are handled during whitespace replacement. If set to
+  # 'use-space', fractional indentation is left as spaces (utf-8 0x20). If set
+  # to `round-up` fractional indentation is replaced with a single tab character
+  # (utf-8 0x09) effectively shifting the column to the next tabstop
+  fractional_tab_policy = 'use-space'
+
+  # If an argument group contains more than this many sub-groups (parg or kwarg
+  # groups) then force it to a vertical layout.
+  max_subgroups_hwrap = 3
+
+  # If a positional argument group contains more than this many arguments, then
+  # force it to a vertical layout.
+  max_pargs_hwrap = 6
+
+  # If a cmdline positional group consumes more than this many lines without
+  # nesting, then invalidate the layout (and nest)
+  max_rows_cmdline = 2
+
+  # If true, separate flow control names from their parentheses with a space
+  separate_ctrl_name_with_space = False
+
+  # If true, separate function names from parentheses with a space
+  separate_fn_name_with_space = False
+
+  # If a statement is wrapped to more than one line, than dangle the closing
+  # parenthesis on its own line.
+  dangle_parens = False
+
+  # If the trailing parenthesis must be 'dangled' on its on line, then align it
+  # to this reference: `prefix`: the start of the statement,  `prefix-indent`:
+  # the start of the statement, plus one indentation  level, `child`: align to
+  # the column of the arguments
+  dangle_align = 'prefix'
+
+  # If the statement spelling length (including space and parenthesis) is
+  # smaller than this amount, then force reject nested layouts.
+  min_prefix_chars = 4
+
+  # If the statement spelling length (including space and parenthesis) is larger
+  # than the tab width by more than this amount, then force reject un-nested
+  # layouts.
+  max_prefix_chars = 10
+
+  # If a candidate layout is wrapped horizontally but it exceeds this many
+  # lines, then reject the layout.
+  max_lines_hwrap = 2
+
+  # What style line endings to use in the output.
+  line_ending = 'unix'
+
+  # Format command names consistently as 'lower' or 'upper' case
+  command_case = 'canonical'
+
+  # Format keywords consistently as 'lower' or 'upper' case
+  keyword_case = 'unchanged'
+
+  # A list of command names which should always be wrapped
+  always_wrap = []
+
+  # If true, the argument lists which are known to be sortable will be sorted
+  # lexicographicall
+  enable_sort = True
+
+  # If true, the parsers may infer whether or not an argument list is sortable
+  # (without annotation).
+  autosort = False
+
+  # By default, if cmake-format cannot successfully fit everything into the
+  # desired linewidth it will apply the last, most agressive attempt that it
+  # made. If this flag is True, however, cmake-format will print error, exit
+  # with non-zero status code, and write-out nothing
+  require_valid_layout = False
+
+  # A dictionary mapping layout nodes to a list of wrap decisions. See the
+  # documentation for more information.
+  layout_passes = {}
+
+# ------------------------------------------------
+# Options affecting comment reflow and formatting.
+# ------------------------------------------------
+with section("markup"):
+
+  # What character to use for bulleted lists
+  bullet_char = '*'
+
+  # What character to use as punctuation after numerals in an enumerated list
+  enum_char = '.'
+
+  # If comment markup is enabled, don't reflow the first comment block in each
+  # listfile. Use this to preserve formatting of your copyright/license
+  # statements.
+  first_comment_is_literal = True
+
+  # If comment markup is enabled, don't reflow any comment block which matches
+  # this (regex) pattern. Default is `None` (disabled).
+  literal_comment_pattern = None
+
+  # Regular expression to match preformat fences in comments default=
+  # ``r'^\s*([`~]{3}[`~]*)(.*)$'``
+  fence_pattern = '^\\s*([`~]{3}[`~]*)(.*)$'
+
+  # Regular expression to match rulers in comments default=
+  # ``r'^\s*[^\w\s]{3}.*[^\w\s]{3}$'``
+  ruler_pattern = '^\\s*[^\\w\\s]{3}.*[^\\w\\s]{3}$'
+
+  # If a comment line matches starts with this pattern then it is explicitly a
+  # trailing comment for the preceeding argument. Default is '#<'
+  explicit_trailing_pattern = '#<'
+
+  # If a comment line starts with at least this many consecutive hash
+  # characters, then don't lstrip() them off. This allows for lazy hash rulers
+  # where the first hash char is not separated by space
+  hashruler_min_length = 10
+
+  # If true, then insert a space between the first hash char and remaining hash
+  # chars in a hash ruler, and normalize its length to fill the column
+  canonicalize_hashrulers = True
+
+  # enable comment markup parsing and reflow
+  enable_markup = True
+
+# ----------------------------
+# Options affecting the linter
+# ----------------------------
+with section("lint"):
+
+  # a list of lint codes to disable
+  disabled_codes = []
+
+  # regular expression pattern describing valid function names
+  function_pattern = '[0-9a-z_]+'
+
+  # regular expression pattern describing valid macro names
+  macro_pattern = '[0-9A-Z_]+'
+
+  # regular expression pattern describing valid names for variables with global
+  # (cache) scope
+  global_var_pattern = '[A-Z][0-9A-Z_]+'
+
+  # regular expression pattern describing valid names for variables with global
+  # scope (but internal semantic)
+  internal_var_pattern = '_[A-Z][0-9A-Z_]+'
+
+  # regular expression pattern describing valid names for variables with local
+  # scope
+  local_var_pattern = '[a-z][a-z0-9_]+'
+
+  # regular expression pattern describing valid names for privatedirectory
+  # variables
+  private_var_pattern = '_[0-9a-z_]+'
+
+  # regular expression pattern describing valid names for public directory
+  # variables
+  public_var_pattern = '[A-Z][0-9A-Z_]+'
+
+  # regular expression pattern describing valid names for function/macro
+  # arguments and loop variables.
+  argument_var_pattern = '[a-z][a-z0-9_]+'
+
+  # regular expression pattern describing valid names for keywords used in
+  # functions or macros
+  keyword_pattern = '[A-Z][0-9A-Z_]+'
+
+  # In the heuristic for C0201, how many conditionals to match within a loop in
+  # before considering the loop a parser.
+  max_conditionals_custom_parser = 2
+
+  # Require at least this many newlines between statements
+  min_statement_spacing = 1
+
+  # Require no more than this many newlines between statements
+  max_statement_spacing = 2
+  max_returns = 6
+  max_branches = 12
+  max_arguments = 5
+  max_localvars = 15
+  max_statements = 50
+
+# -------------------------------
+# Options affecting file encoding
+# -------------------------------
+with section("encode"):
+
+  # If true, emit the unicode byte-order mark (BOM) at the start of the file
+  emit_byteorder_mark = False
+
+  # Specify the encoding of the input file. Defaults to utf-8
+  input_encoding = 'utf-8'
+
+  # Specify the encoding of the output file. Defaults to utf-8. Note that cmake
+  # only claims to support utf-8 so be careful when using anything else
+  output_encoding = 'utf-8'
+
+# -------------------------------------
+# Miscellaneous configurations options.
+# -------------------------------------
+with section("misc"):
+
+  # A dictionary containing any per-command configuration overrides. Currently
+  # only `command_case` is supported.
+  per_command = {}
--- a/external/libwebp/libwebp/.gitattributes
+++ b/external/libwebp/libwebp/.gitattributes
@@ -0,0 +1,6 @@
+.gitattributes export-ignore
+.gitignore export-ignore
+.mailmap export-ignore
+*.bat text eol=crlf
+*.pdf -text -diff
+*.ppm -text -diff
--- a/external/libwebp/libwebp/.gitignore
+++ b/external/libwebp/libwebp/.gitignore
@@ -0,0 +1,56 @@
+*.l[ao]
+*.[ao]
+*.pc
+.DS_Store
+.deps
+.idea
+.libs
+.vscode
+/aclocal.m4
+/ar-lib
+/autom4te.cache
+/compile
+/config.*
+/configure
+/depcomp
+/dist
+/install-sh
+/libtool
+/ltmain.sh
+/missing
+/mkinstalldirs
+/stamp-h1
+Makefile
+Makefile.in
+examples/anim_diff
+examples/anim_dump
+examples/[cdv]webp
+examples/gif2webp
+examples/img2webp
+examples/webpinfo
+examples/webpmux
+src/webp/config.h*
+src/webp/stamp-h1
+/output
+/doc/output
+*.idb
+*.pdb
+/iosbuild
+/xcframeworkbuild
+/WebP*.*framework
+CMakeCache.txt
+CMakeFiles/
+cmake_install.cmake
+.gradle
+/build
+extras/get_disto
+extras/vwebp_sdl
+extras/webp_quality
+tests/fuzzer/advanced_api_fuzzer
+tests/fuzzer/animation_api_fuzzer
+tests/fuzzer/animdecoder_fuzzer
+tests/fuzzer/animencoder_fuzzer
+tests/fuzzer/demux_api_fuzzer
+tests/fuzzer/enc_dec_fuzzer
+tests/fuzzer/mux_demux_api_fuzzer
+tests/fuzzer/simple_api_fuzzer
--- a/external/libwebp/libwebp/.mailmap
+++ b/external/libwebp/libwebp/.mailmap
@@ -0,0 +1,19 @@
+Johann Koenig <johann.koenig@duck.com>
+Johann Koenig <johann.koenig@duck.com> <johannkoenig@google.com>
+Mikołaj Zalewski <mikolajz@google.com>
+Pascal Massimino <pascal.massimino@gmail.com>
+Pascal Massimino <pascal.massimino@gmail.com> <skal@google.com>
+Vikas Arora <vikasa@google.com>
+<vikasa@google.com> <vikasa@gmail.com>
+<vikasa@google.com> <vikaas.arora@gmail.com>
+<slobodan.prijic@imgtec.com> <Slobodan.Prijic@imgtec.com>
+<vrabaud@google.com> <vincent.rabaud@gmail.com>
+Vincent Rabaud <vrabaud@google.com>
+Tamar Levy <tamar.levy@intel.com>
+<qrczak@google.com> <qrczak>
+Hui Su <huisu@google.com>
+James Zern <jzern@google.com>
+Roberto Alanis <alanisbaez@google.com>
+Brian Ledger <brianpl@google.com>
+Maryla Ustarroz-Calonge <maryla@google.com>
+Yannis Guyon <yguyon@google.com>
--- a/external/libwebp/libwebp/.pylintrc
+++ b/external/libwebp/libwebp/.pylintrc
@@ -0,0 +1,441 @@
+# This Pylint rcfile contains a best-effort configuration to uphold the
+# best-practices and style described in the Google Python style guide:
+#   https://google.github.io/styleguide/pyguide.html
+#
+# Its canonical open-source location is:
+#   https://google.github.io/styleguide/pylintrc
+
+[MASTER]
+
+# Files or directories to be skipped. They should be base names, not paths.
+ignore=third_party
+
+# Files or directories matching the regex patterns are skipped. The regex
+# matches against base names, not paths.
+ignore-patterns=
+
+# Pickle collected data for later comparisons.
+persistent=no
+
+# List of plugins (as comma separated values of python modules names) to load,
+# usually to register additional checkers.
+load-plugins=
+
+# Use multiple processes to speed up Pylint.
+jobs=4
+
+# Allow loading of arbitrary C extensions. Extensions are imported into the
+# active Python interpreter and may run arbitrary code.
+unsafe-load-any-extension=no
+
+
+[MESSAGES CONTROL]
+
+# Only show warnings with the listed confidence levels. Leave empty to show
+# all. Valid levels: HIGH, INFERENCE, INFERENCE_FAILURE, UNDEFINED
+confidence=
+
+# Enable the message, report, category or checker with the given id(s). You can
+# either give multiple identifier separated by comma (,) or put this option
+# multiple time (only on the command line, not in the configuration file where
+# it should appear only once). See also the "--disable" option for examples.
+#enable=
+
+# Disable the message, report, category or checker with the given id(s). You
+# can either give multiple identifiers separated by comma (,) or put this
+# option multiple times (only on the command line, not in the configuration
+# file where it should appear only once).You can also use "--disable=all" to
+# disable everything first and then reenable specific checks. For example, if
+# you want to run only the similarities checker, you can use "--disable=all
+# --enable=similarities". If you want to run only the classes checker, but have
+# no Warning level messages displayed, use"--disable=all --enable=classes
+# --disable=W"
+disable=abstract-method,
+        apply-builtin,
+        arguments-differ,
+        attribute-defined-outside-init,
+        backtick,
+        bad-option-value,
+        basestring-builtin,
+        buffer-builtin,
+        c-extension-no-member,
+        consider-using-enumerate,
+        cmp-builtin,
+        cmp-method,
+        coerce-builtin,
+        coerce-method,
+        delslice-method,
+        div-method,
+        duplicate-code,
+        eq-without-hash,
+        execfile-builtin,
+        file-builtin,
+        filter-builtin-not-iterating,
+        fixme,
+        getslice-method,
+        global-statement,
+        hex-method,
+        idiv-method,
+        implicit-str-concat-in-sequence,
+        import-error,
+        import-self,
+        import-star-module-level,
+        inconsistent-return-statements,
+        input-builtin,
+        intern-builtin,
+        invalid-str-codec,
+        locally-disabled,
+        long-builtin,
+        long-suffix,
+        map-builtin-not-iterating,
+        misplaced-comparison-constant,
+        missing-function-docstring,
+        metaclass-assignment,
+        next-method-called,
+        next-method-defined,
+        no-absolute-import,
+        no-else-break,
+        no-else-continue,
+        no-else-raise,
+        no-else-return,
+        no-init,  # added
+        no-member,
+        no-name-in-module,
+        no-self-use,
+        nonzero-method,
+        oct-method,
+        old-division,
+        old-ne-operator,
+        old-octal-literal,
+        old-raise-syntax,
+        parameter-unpacking,
+        print-statement,
+        raising-string,
+        range-builtin-not-iterating,
+        raw_input-builtin,
+        rdiv-method,
+        reduce-builtin,
+        relative-import,
+        reload-builtin,
+        round-builtin,
+        setslice-method,
+        signature-differs,
+        standarderror-builtin,
+        suppressed-message,
+        sys-max-int,
+        too-few-public-methods,
+        too-many-ancestors,
+        too-many-arguments,
+        too-many-boolean-expressions,
+        too-many-branches,
+        too-many-instance-attributes,
+        too-many-locals,
+        too-many-nested-blocks,
+        too-many-public-methods,
+        too-many-return-statements,
+        too-many-statements,
+        trailing-newlines,
+        unichr-builtin,
+        unicode-builtin,
+        unnecessary-pass,
+        unpacking-in-except,
+        useless-else-on-loop,
+        useless-object-inheritance,
+        useless-suppression,
+        using-cmp-argument,
+        wrong-import-order,
+        xrange-builtin,
+        zip-builtin-not-iterating,
+
+
+[REPORTS]
+
+# Set the output format. Available formats are text, parseable, colorized, msvs
+# (visual studio) and html. You can also give a reporter class, eg
+# mypackage.mymodule.MyReporterClass.
+output-format=text
+
+# Put messages in a separate file for each module / package specified on the
+# command line instead of printing them on stdout. Reports (if any) will be
+# written in a file name "pylint_global.[txt|html]". This option is deprecated
+# and it will be removed in Pylint 2.0.
+files-output=no
+
+# Tells whether to display a full report or only the messages
+reports=no
+
+# Python expression which should return a note less than 10 (10 is the highest
+# note). You have access to the variables errors warning, statement which
+# respectively contain the number of errors / warnings messages and the total
+# number of statements analyzed. This is used by the global evaluation report
+# (RP0004).
+evaluation=10.0 - ((float(5 * error + warning + refactor + convention) / statement) * 10)
+
+# Template used to display messages. This is a python new-style format string
+# used to format the message information. See doc for all details
+#msg-template=
+
+
+[BASIC]
+
+# Good variable names which should always be accepted, separated by a comma
+good-names=main,_,PRESUBMIT
+
+# Bad variable names which should always be refused, separated by a comma
+bad-names=
+
+# Colon-delimited sets of names that determine each other's naming style when
+# the name regexes allow several styles.
+name-group=
+
+# Include a hint for the correct naming format with invalid-name
+include-naming-hint=no
+
+# List of decorators that produce properties, such as abc.abstractproperty. Add
+# to this list to register other decorators that produce valid properties.
+property-classes=abc.abstractproperty,cached_property.cached_property,cached_property.threaded_cached_property,cached_property.cached_property_with_ttl,cached_property.threaded_cached_property_with_ttl
+
+# Regular expression matching correct function names
+function-rgx=^(?:(?P<exempt>setUp|tearDown|setUpModule|tearDownModule)|(?P<camel_case>_?[A-Z][a-zA-Z0-9]*)|(?P<snake_case>_?[a-z][a-z0-9_]*))$
+
+# Regular expression matching correct variable names
+variable-rgx=^[a-z][a-z0-9_]*$
+
+# Regular expression matching correct constant names
+const-rgx=^(_?[A-Z][A-Z0-9_]*|__[a-z0-9_]+__|_?[a-z][a-z0-9_]*)$
+
+# Regular expression matching correct attribute names
+attr-rgx=^_{0,2}[a-z][a-z0-9_]*$
+
+# Regular expression matching correct argument names
+argument-rgx=^[a-z][a-z0-9_]*$
+
+# Regular expression matching correct class attribute names
+class-attribute-rgx=^(_?[A-Z][A-Z0-9_]*|__[a-z0-9_]+__|_?[a-z][a-z0-9_]*)$
+
+# Regular expression matching correct inline iteration names
+inlinevar-rgx=^[a-z][a-z0-9_]*$
+
+# Regular expression matching correct class names
+class-rgx=^_?[A-Z][a-zA-Z0-9]*$
+
+# Regular expression matching correct module names
+module-rgx=^(_?[a-z][a-z0-9_]*|__init__)$
+
+# Regular expression matching correct method names
+method-rgx=(?x)^(?:(?P<exempt>_[a-z0-9_]+__|runTest|setUp|tearDown|setUpTestCase|tearDownTestCase|setupSelf|tearDownClass|setUpClass|(test|assert)_*[A-Z0-9][a-zA-Z0-9_]*|next)|(?P<camel_case>_{0,2}[A-Z][a-zA-Z0-9_]*)|(?P<snake_case>_{0,2}[a-z][a-z0-9_]*))$
+
+# Regular expression which should only match function or class names that do
+# not require a docstring.
+no-docstring-rgx=(__.*__|main|test.*|.*test|.*Test)$
+
+# Minimum line length for functions/classes that require docstrings, shorter
+# ones are exempt.
+docstring-min-length=10
+
+
+[TYPECHECK]
+
+# List of decorators that produce context managers, such as
+# contextlib.contextmanager. Add to this list to register other decorators that
+# produce valid context managers.
+contextmanager-decorators=contextlib.contextmanager,contextlib2.contextmanager
+
+# Tells whether missing members accessed in mixin class should be ignored. A
+# mixin class is detected if its name ends with "mixin" (case insensitive).
+ignore-mixin-members=yes
+
+# List of module names for which member attributes should not be checked
+# (useful for modules/projects where namespaces are manipulated during runtime
+# and thus existing member attributes cannot be deduced by static analysis. It
+# supports qualified module names, as well as Unix pattern matching.
+ignored-modules=
+
+# List of class names for which member attributes should not be checked (useful
+# for classes with dynamically set attributes). This supports the use of
+# qualified names.
+ignored-classes=optparse.Values,thread._local,_thread._local
+
+# List of members which are set dynamically and missed by pylint inference
+# system, and so shouldn't trigger E1101 when accessed. Python regular
+# expressions are accepted.
+generated-members=
+
+
+[FORMAT]
+
+# Maximum number of characters on a single line.
+max-line-length=80
+
+# TODO(https://github.com/PyCQA/pylint/issues/3352): Direct pylint to exempt
+# lines made too long by directives to pytype.
+
+# Regexp for a line that is allowed to be longer than the limit.
+ignore-long-lines=(?x)(
+  ^\s*(\#\ )?<?https?://\S+>?$|
+  ^\s*(from\s+\S+\s+)?import\s+.+$)
+
+# Allow the body of an if to be on the same line as the test if there is no
+# else.
+single-line-if-stmt=yes
+
+# List of optional constructs for which whitespace checking is disabled. `dict-
+# separator` is used to allow tabulation in dicts, etc.: {1  : 1,\n222: 2}.
+# `trailing-comma` allows a space between comma and closing bracket: (a, ).
+# `empty-line` allows space-only lines.
+no-space-check=
+
+# Maximum number of lines in a module
+max-module-lines=99999
+
+# String used as indentation unit.  The internal Google style guide mandates 2
+# spaces.  Google's externaly-published style guide says 4, consistent with
+# PEP 8.  Here, we use 2 spaces, for conformity with many open-sourced Google
+# projects (like TensorFlow).
+indent-string='  '
+
+# Number of spaces of indent required inside a hanging  or continued line.
+indent-after-paren=4
+
+# Expected format of line ending, e.g. empty (any line ending), LF or CRLF.
+expected-line-ending-format=
+
+
+[MISCELLANEOUS]
+
+# List of note tags to take in consideration, separated by a comma.
+notes=TODO
+
+
+[STRING]
+
+# This flag controls whether inconsistent-quotes generates a warning when the
+# character used as a quote delimiter is used inconsistently within a module.
+check-quote-consistency=yes
+
+
+[VARIABLES]
+
+# Tells whether we should check for unused import in __init__ files.
+init-import=no
+
+# A regular expression matching the name of dummy variables (i.e. expectedly
+# not used).
+dummy-variables-rgx=^\*{0,2}(_$|unused_|dummy_)
+
+# List of additional names supposed to be defined in builtins. Remember that
+# you should avoid to define new builtins when possible.
+additional-builtins=
+
+# List of strings which can identify a callback function by name. A callback
+# name must start or end with one of those strings.
+callbacks=cb_,_cb
+
+# List of qualified module names which can have objects that can redefine
+# builtins.
+redefining-builtins-modules=six,six.moves,past.builtins,future.builtins,functools
+
+
+[LOGGING]
+
+# Logging modules to check that the string format arguments are in logging
+# function parameter format
+logging-modules=logging,absl.logging,tensorflow.io.logging
+
+
+[SIMILARITIES]
+
+# Minimum lines number of a similarity.
+min-similarity-lines=4
+
+# Ignore comments when computing similarities.
+ignore-comments=yes
+
+# Ignore docstrings when computing similarities.
+ignore-docstrings=yes
+
+# Ignore imports when computing similarities.
+ignore-imports=no
+
+
+[SPELLING]
+
+# Spelling dictionary name. Available dictionaries: none. To make it working
+# install python-enchant package.
+spelling-dict=
+
+# List of comma separated words that should not be checked.
+spelling-ignore-words=
+
+# A path to a file that contains private dictionary; one word per line.
+spelling-private-dict-file=
+
+# Tells whether to store unknown words to indicated private dictionary in
+# --spelling-private-dict-file option instead of raising a message.
+spelling-store-unknown-words=no
+
+
+[IMPORTS]
+
+# Deprecated modules which should not be used, separated by a comma
+deprecated-modules=regsub,
+                   TERMIOS,
+                   Bastion,
+                   rexec,
+                   sets
+
+# Create a graph of every (i.e. internal and external) dependencies in the
+# given file (report RP0402 must not be disabled)
+import-graph=
+
+# Create a graph of external dependencies in the given file (report RP0402 must
+# not be disabled)
+ext-import-graph=
+
+# Create a graph of internal dependencies in the given file (report RP0402 must
+# not be disabled)
+int-import-graph=
+
+# Force import order to recognize a module as part of the standard
+# compatibility libraries.
+known-standard-library=
+
+# Force import order to recognize a module as part of a third party library.
+known-third-party=enchant, absl
+
+# Analyse import fallback blocks. This can be used to support both Python 2 and
+# 3 compatible code, which means that the block might have code that exists
+# only in one or another interpreter, leading to false positives when analysed.
+analyse-fallback-blocks=no
+
+
+[CLASSES]
+
+# List of method names used to declare (i.e. assign) instance attributes.
+defining-attr-methods=__init__,
+                      __new__,
+                      setUp
+
+# List of member names, which should be excluded from the protected access
+# warning.
+exclude-protected=_asdict,
+                  _fields,
+                  _replace,
+                  _source,
+                  _make
+
+# List of valid names for the first argument in a class method.
+valid-classmethod-first-arg=cls,
+                            class_
+
+# List of valid names for the first argument in a metaclass class method.
+valid-metaclass-classmethod-first-arg=mcs
+
+
+[EXCEPTIONS]
+
+# Exceptions that will emit a warning when being caught. Defaults to
+# "Exception"
+overgeneral-exceptions=StandardError,
+                       Exception,
+                       BaseException
--- a/external/libwebp/libwebp/.style.yapf
+++ b/external/libwebp/libwebp/.style.yapf
@@ -0,0 +1,2 @@
+[style]
+based_on_style = yapf
--- a/external/libwebp/libwebp/AUTHORS
+++ b/external/libwebp/libwebp/AUTHORS
@@ -0,0 +1,60 @@
+Contributors:
+- Aidan O'Loan (aidanol at gmail dot com)
+- Alan Browning (browning at google dot com)
+- Alexandru Ardelean (ardeleanalex at gmail dot com)
+- Brian Ledger (brianpl at google dot com)
+- Charles Munger (clm at google dot com)
+- Cheng Yi (cyi at google dot com)
+- Christian Duvivier (cduvivier at google dot com)
+- Christopher Degawa (ccom at randomderp dot com)
+- Clement Courbet (courbet at google dot com)
+- Djordje Pesut (djordje dot pesut at imgtec dot com)
+- Frank Barchard (fbarchard at google dot com)
+- Hui Su (huisu at google dot com)
+- H. Vetinari (h dot vetinari at gmx dot com)
+- Ilya Kurdyukov (jpegqs at gmail dot com)
+- Ingvar Stepanyan (rreverser at google dot com)
+- James Zern (jzern at google dot com)
+- Jan Engelhardt (jengelh at medozas dot de)
+- Jehan (jehan at girinstud dot io)
+- Jeremy Maitin-Shepard (jbms at google dot com)
+- Johann Koenig (johann dot koenig at duck dot com)
+- Jovan Zelincevic (jovan dot zelincevic at imgtec dot com)
+- Jyrki Alakuijala (jyrki at google dot com)
+- Konstantin Ivlev (tomskside at gmail dot com)
+- Lode Vandevenne (lode at google dot com)
+- Lou Quillio (louquillio at google dot com)
+- Mans Rullgard (mans at mansr dot com)
+- Marcin Kowalczyk (qrczak at google dot com)
+- Martin Olsson (mnemo at minimum dot se)
+- Maryla Ustarroz-Calonge (maryla at google dot com)
+- Mikołaj Zalewski (mikolajz at google dot com)
+- Mislav Bradac (mislavm at google dot com)
+- Nico Weber (thakis at chromium dot org)
+- Noel Chromium (noel at chromium dot org)
+- Nozomi Isozaki (nontan at pixiv dot co dot jp)
+- Oliver Wolff (oliver dot wolff at qt dot io)
+- Owen Rodley (orodley at google dot com)
+- Parag Salasakar (img dot mips1 at gmail dot com)
+- Pascal Massimino (pascal dot massimino at gmail dot com)
+- Paweł Hajdan, Jr (phajdan dot jr at chromium dot org)
+- Pierre Joye (pierre dot php at gmail dot com)
+- Roberto Alanis (alanisbaez at google dot com)
+- Sam Clegg (sbc at chromium dot org)
+- Scott Hancher (seh at google dot com)
+- Scott LaVarnway (slavarnway at google dot com)
+- Scott Talbot (s at chikachow dot org)
+- Slobodan Prijic (slobodan dot prijic at imgtec dot com)
+- Somnath Banerjee (somnath dot banerjee at gmail dot com)
+- Sriraman Tallam (tmsriram at google dot com)
+- Tamar Levy (tamar dot levy at intel dot com)
+- Thiago Perrotta (tperrotta at google dot com)
+- Timothy Gu (timothygu99 at gmail dot com)
+- Urvang Joshi (urvang at google dot com)
+- Vikas Arora (vikasa at google dot com)
+- Vincent Rabaud (vrabaud at google dot com)
+- Vlad Tsyrklevich (vtsyrklevich at chromium dot org)
+- Wan-Teh Chang (wtc at google dot com)
+- Yang Zhang (yang dot zhang at arm dot com)
+- Yannis Guyon (yguyon at google dot com)
+- Zhi An Ng (zhin at chromium dot org)
--- a/external/libwebp/libwebp/Android.mk
+++ b/external/libwebp/libwebp/Android.mk
@@ -0,0 +1,295 @@
+# Ignore this file during non-NDK builds.
+ifdef NDK_ROOT
+LOCAL_PATH := $(call my-dir)
+
+WEBP_CFLAGS := -Wall -DANDROID -DHAVE_MALLOC_H -DHAVE_PTHREAD -DWEBP_USE_THREAD
+WEBP_CFLAGS += -fvisibility=hidden
+
+ifeq ($(APP_OPTIM),release)
+  WEBP_CFLAGS += -finline-functions -ffast-math \
+                 -ffunction-sections -fdata-sections
+  ifeq ($(findstring clang,$(NDK_TOOLCHAIN_VERSION)),)
+    WEBP_CFLAGS += -frename-registers -s
+  endif
+endif
+
+# mips32 fails to build with clang from r14b
+# https://bugs.chromium.org/p/webp/issues/detail?id=343
+ifeq ($(findstring clang,$(NDK_TOOLCHAIN_VERSION)),clang)
+  ifeq ($(TARGET_ARCH),mips)
+    clang_version := $(shell $(TARGET_CC) --version)
+    ifneq ($(findstring clang version 3,$(clang_version)),)
+      WEBP_CFLAGS += -no-integrated-as
+    endif
+  endif
+endif
+
+ifneq ($(findstring armeabi-v7a, $(TARGET_ARCH_ABI)),)
+  # Setting LOCAL_ARM_NEON will enable -mfpu=neon which may cause illegal
+  # instructions to be generated for armv7a code. Instead target the neon code
+  # specifically.
+  NEON := c.neon
+  USE_CPUFEATURES := yes
+  WEBP_CFLAGS += -DHAVE_CPU_FEATURES_H
+else
+  NEON := c
+endif
+
+sharpyuv_srcs := \
+    sharpyuv/sharpyuv.c \
+    sharpyuv/sharpyuv_cpu.c \
+    sharpyuv/sharpyuv_csp.c \
+    sharpyuv/sharpyuv_dsp.c \
+    sharpyuv/sharpyuv_gamma.c \
+    sharpyuv/sharpyuv_neon.$(NEON) \
+    sharpyuv/sharpyuv_sse2.c \
+
+dec_srcs := \
+    src/dec/alpha_dec.c \
+    src/dec/buffer_dec.c \
+    src/dec/frame_dec.c \
+    src/dec/idec_dec.c \
+    src/dec/io_dec.c \
+    src/dec/quant_dec.c \
+    src/dec/tree_dec.c \
+    src/dec/vp8_dec.c \
+    src/dec/vp8l_dec.c \
+    src/dec/webp_dec.c \
+
+demux_srcs := \
+    src/demux/anim_decode.c \
+    src/demux/demux.c \
+
+dsp_dec_srcs := \
+    src/dsp/alpha_processing.c \
+    src/dsp/alpha_processing_mips_dsp_r2.c \
+    src/dsp/alpha_processing_neon.$(NEON) \
+    src/dsp/alpha_processing_sse2.c \
+    src/dsp/alpha_processing_sse41.c \
+    src/dsp/cpu.c \
+    src/dsp/dec.c \
+    src/dsp/dec_clip_tables.c \
+    src/dsp/dec_mips32.c \
+    src/dsp/dec_mips_dsp_r2.c \
+    src/dsp/dec_msa.c \
+    src/dsp/dec_neon.$(NEON) \
+    src/dsp/dec_sse2.c \
+    src/dsp/dec_sse41.c \
+    src/dsp/filters.c \
+    src/dsp/filters_mips_dsp_r2.c \
+    src/dsp/filters_msa.c \
+    src/dsp/filters_neon.$(NEON) \
+    src/dsp/filters_sse2.c \
+    src/dsp/lossless.c \
+    src/dsp/lossless_mips_dsp_r2.c \
+    src/dsp/lossless_msa.c \
+    src/dsp/lossless_neon.$(NEON) \
+    src/dsp/lossless_sse2.c \
+    src/dsp/lossless_sse41.c \
+    src/dsp/rescaler.c \
+    src/dsp/rescaler_mips32.c \
+    src/dsp/rescaler_mips_dsp_r2.c \
+    src/dsp/rescaler_msa.c \
+    src/dsp/rescaler_neon.$(NEON) \
+    src/dsp/rescaler_sse2.c \
+    src/dsp/upsampling.c \
+    src/dsp/upsampling_mips_dsp_r2.c \
+    src/dsp/upsampling_msa.c \
+    src/dsp/upsampling_neon.$(NEON) \
+    src/dsp/upsampling_sse2.c \
+    src/dsp/upsampling_sse41.c \
+    src/dsp/yuv.c \
+    src/dsp/yuv_mips32.c \
+    src/dsp/yuv_mips_dsp_r2.c \
+    src/dsp/yuv_neon.$(NEON) \
+    src/dsp/yuv_sse2.c \
+    src/dsp/yuv_sse41.c \
+
+dsp_enc_srcs := \
+    src/dsp/cost.c \
+    src/dsp/cost_mips32.c \
+    src/dsp/cost_mips_dsp_r2.c \
+    src/dsp/cost_neon.$(NEON) \
+    src/dsp/cost_sse2.c \
+    src/dsp/enc.c \
+    src/dsp/enc_mips32.c \
+    src/dsp/enc_mips_dsp_r2.c \
+    src/dsp/enc_msa.c \
+    src/dsp/enc_neon.$(NEON) \
+    src/dsp/enc_sse2.c \
+    src/dsp/enc_sse41.c \
+    src/dsp/lossless_enc.c \
+    src/dsp/lossless_enc_mips32.c \
+    src/dsp/lossless_enc_mips_dsp_r2.c \
+    src/dsp/lossless_enc_msa.c \
+    src/dsp/lossless_enc_neon.$(NEON) \
+    src/dsp/lossless_enc_sse2.c \
+    src/dsp/lossless_enc_sse41.c \
+    src/dsp/ssim.c \
+    src/dsp/ssim_sse2.c \
+
+enc_srcs := \
+    src/enc/alpha_enc.c \
+    src/enc/analysis_enc.c \
+    src/enc/backward_references_cost_enc.c \
+    src/enc/backward_references_enc.c \
+    src/enc/config_enc.c \
+    src/enc/cost_enc.c \
+    src/enc/filter_enc.c \
+    src/enc/frame_enc.c \
+    src/enc/histogram_enc.c \
+    src/enc/iterator_enc.c \
+    src/enc/near_lossless_enc.c \
+    src/enc/picture_enc.c \
+    src/enc/picture_csp_enc.c \
+    src/enc/picture_psnr_enc.c \
+    src/enc/picture_rescale_enc.c \
+    src/enc/picture_tools_enc.c \
+    src/enc/predictor_enc.c \
+    src/enc/quant_enc.c \
+    src/enc/syntax_enc.c \
+    src/enc/token_enc.c \
+    src/enc/tree_enc.c \
+    src/enc/vp8l_enc.c \
+    src/enc/webp_enc.c \
+
+mux_srcs := \
+    src/mux/anim_encode.c \
+    src/mux/muxedit.c \
+    src/mux/muxinternal.c \
+    src/mux/muxread.c \
+
+utils_dec_srcs := \
+    src/utils/bit_reader_utils.c \
+    src/utils/color_cache_utils.c \
+    src/utils/filters_utils.c \
+    src/utils/huffman_utils.c \
+    src/utils/palette.c \
+    src/utils/quant_levels_dec_utils.c \
+    src/utils/random_utils.c \
+    src/utils/rescaler_utils.c \
+    src/utils/thread_utils.c \
+    src/utils/utils.c \
+
+utils_enc_srcs := \
+    src/utils/bit_writer_utils.c \
+    src/utils/huffman_encode_utils.c \
+    src/utils/quant_levels_utils.c \
+
+################################################################################
+# libwebpdecoder
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    $(dec_srcs) \
+    $(dsp_dec_srcs) \
+    $(utils_dec_srcs) \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_EXPORT_C_INCLUDES += $(LOCAL_PATH)/src
+
+# prefer arm over thumb mode for performance gains
+LOCAL_ARM_MODE := arm
+
+ifeq ($(USE_CPUFEATURES),yes)
+  LOCAL_STATIC_LIBRARIES := cpufeatures
+endif
+
+LOCAL_MODULE := webpdecoder_static
+
+include $(BUILD_STATIC_LIBRARY)
+
+ifeq ($(ENABLE_SHARED),1)
+include $(CLEAR_VARS)
+
+LOCAL_WHOLE_STATIC_LIBRARIES := webpdecoder_static
+
+LOCAL_MODULE := webpdecoder
+
+include $(BUILD_SHARED_LIBRARY)
+endif  # ENABLE_SHARED=1
+
+################################################################################
+# libwebp
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    $(sharpyuv_srcs) \
+    $(dsp_enc_srcs) \
+    $(enc_srcs) \
+    $(utils_enc_srcs) \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_EXPORT_C_INCLUDES += $(LOCAL_PATH)/src $(LOCAL_PATH)
+
+# prefer arm over thumb mode for performance gains
+LOCAL_ARM_MODE := arm
+
+LOCAL_WHOLE_STATIC_LIBRARIES := webpdecoder_static
+
+LOCAL_MODULE := webp
+
+ifeq ($(ENABLE_SHARED),1)
+  include $(BUILD_SHARED_LIBRARY)
+else
+  include $(BUILD_STATIC_LIBRARY)
+endif
+
+################################################################################
+# libwebpdemux
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := $(demux_srcs)
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_EXPORT_C_INCLUDES += $(LOCAL_PATH)/src
+
+# prefer arm over thumb mode for performance gains
+LOCAL_ARM_MODE := arm
+
+LOCAL_MODULE := webpdemux
+
+ifeq ($(ENABLE_SHARED),1)
+  LOCAL_SHARED_LIBRARIES := webp
+  include $(BUILD_SHARED_LIBRARY)
+else
+  LOCAL_STATIC_LIBRARIES := webp
+  include $(BUILD_STATIC_LIBRARY)
+endif
+
+################################################################################
+# libwebpmux
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := $(mux_srcs)
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_EXPORT_C_INCLUDES += $(LOCAL_PATH)/src
+
+# prefer arm over thumb mode for performance gains
+LOCAL_ARM_MODE := arm
+
+LOCAL_MODULE := webpmux
+
+ifeq ($(ENABLE_SHARED),1)
+  LOCAL_SHARED_LIBRARIES := webp
+  include $(BUILD_SHARED_LIBRARY)
+else
+  LOCAL_STATIC_LIBRARIES := webp
+  include $(BUILD_STATIC_LIBRARY)
+endif
+
+################################################################################
+
+WEBP_SRC_PATH := $(LOCAL_PATH)
+include $(WEBP_SRC_PATH)/imageio/Android.mk
+include $(WEBP_SRC_PATH)/examples/Android.mk
+
+ifeq ($(USE_CPUFEATURES),yes)
+  $(call import-module,android/cpufeatures)
+endif
+endif  # NDK_ROOT
--- a/external/libwebp/libwebp/CMakeLists.txt
+++ b/external/libwebp/libwebp/CMakeLists.txt
@@ -0,0 +1,802 @@
+#  Copyright (c) 2020 Google LLC.
+#
+#  Use of this source code is governed by a BSD-style license
+#  that can be found in the LICENSE file in the root of the source
+#  tree. An additional intellectual property rights grant can be found
+#  in the file PATENTS.  All contributing project authors may
+#  be found in the AUTHORS file in the root of the source tree.
+
+if(APPLE)
+  cmake_minimum_required(VERSION 3.17)
+else()
+  cmake_minimum_required(VERSION 3.7)
+endif()
+
+if(POLICY CMP0072)
+  cmake_policy(SET CMP0072 NEW)
+endif()
+
+project(WebP C)
+
+# Options for coder / decoder executables.
+if(BUILD_SHARED_LIBS)
+  set(WEBP_LINK_STATIC_DEFAULT OFF)
+else()
+  set(WEBP_LINK_STATIC_DEFAULT ON)
+endif()
+option(WEBP_LINK_STATIC
+       "Link using static libraries. If OFF, use dynamic libraries."
+       ${WEBP_LINK_STATIC_DEFAULT})
+if(NOT EMSCRIPTEN)
+  # Disable SIMD on Emscripten by default, as it's a new unstable Wasm feature.
+  # Users can still explicitly opt-in to make a SIMD-enabled build.
+  set(WEBP_ENABLE_SIMD_DEFAULT ON)
+endif()
+option(WEBP_ENABLE_SIMD "Enable any SIMD optimization."
+       ${WEBP_ENABLE_SIMD_DEFAULT})
+option(WEBP_BUILD_ANIM_UTILS "Build animation utilities." ON)
+option(WEBP_BUILD_CWEBP "Build the cwebp command line tool." ON)
+option(WEBP_BUILD_DWEBP "Build the dwebp command line tool." ON)
+option(WEBP_BUILD_GIF2WEBP "Build the gif2webp conversion tool." ON)
+option(WEBP_BUILD_IMG2WEBP "Build the img2webp animation tool." ON)
+option(WEBP_BUILD_VWEBP "Build the vwebp viewer tool." ON)
+option(WEBP_BUILD_WEBPINFO "Build the webpinfo command line tool." ON)
+option(WEBP_BUILD_LIBWEBPMUX "Build the libwebpmux library." ON)
+option(WEBP_BUILD_WEBPMUX "Build the webpmux command line tool." ON)
+option(WEBP_BUILD_EXTRAS "Build extras." ON)
+option(WEBP_BUILD_WEBP_JS "Emscripten build of webp.js." OFF)
+option(WEBP_USE_THREAD "Enable threading support" ON)
+option(WEBP_NEAR_LOSSLESS "Enable near-lossless encoding" ON)
+option(WEBP_ENABLE_SWAP_16BIT_CSP "Enable byte swap for 16 bit colorspaces."
+       OFF)
+set(WEBP_BITTRACE "0" CACHE STRING "Bit trace mode (0=none, 1=bit, 2=bytes)")
+set_property(CACHE WEBP_BITTRACE PROPERTY STRINGS 0 1 2)
+
+if(WEBP_LINK_STATIC)
+  if(WIN32)
+    set(CMAKE_FIND_LIBRARY_SUFFIXES .lib .a ${CMAKE_FIND_LIBRARY_SUFFIXES})
+  else()
+    set(CMAKE_FIND_LIBRARY_SUFFIXES .a ${CMAKE_FIND_LIBRARY_SUFFIXES})
+  endif()
+  set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+  # vwebp does not compile on Ubuntu with static libraries so disabling it for
+  # now.
+  set(WEBP_BUILD_VWEBP OFF)
+endif()
+
+# Option needed for handling Unicode file names on Windows.
+if(WIN32)
+  option(WEBP_UNICODE "Build Unicode executables." ON)
+endif()
+
+if(WEBP_BUILD_WEBP_JS)
+  set(WEBP_BUILD_ANIM_UTILS OFF)
+  set(WEBP_BUILD_CWEBP OFF)
+  set(WEBP_BUILD_DWEBP OFF)
+  set(WEBP_BUILD_GIF2WEBP OFF)
+  set(WEBP_BUILD_IMG2WEBP OFF)
+  set(WEBP_BUILD_VWEBP OFF)
+  set(WEBP_BUILD_WEBPINFO OFF)
+  set(WEBP_BUILD_WEBPMUX OFF)
+  set(WEBP_BUILD_EXTRAS OFF)
+  set(WEBP_USE_THREAD OFF)
+
+  if(WEBP_ENABLE_SIMD)
+    message(NOTICE
+            "wasm2js does not support SIMD, disabling webp.js generation.")
+  endif()
+endif()
+
+set(SHARPYUV_DEP_LIBRARIES)
+set(SHARPYUV_DEP_INCLUDE_DIRS)
+set(WEBP_DEP_LIBRARIES)
+set(WEBP_DEP_INCLUDE_DIRS)
+
+if(NOT CMAKE_BUILD_TYPE)
+  set(CMAKE_BUILD_TYPE "Release"
+      CACHE STRING "Build type: Release, Debug, MinSizeRel or RelWithDebInfo"
+            FORCE)
+endif()
+
+# Include dependencies.
+if(WEBP_BUILD_ANIM_UTILS
+   OR WEBP_BUILD_CWEBP
+   OR WEBP_BUILD_DWEBP
+   OR WEBP_BUILD_EXTRAS
+   OR WEBP_BUILD_GIF2WEBP
+   OR WEBP_BUILD_IMG2WEBP)
+  set(WEBP_FIND_IMG_LIBS TRUE)
+else()
+  set(WEBP_FIND_IMG_LIBS FALSE)
+endif()
+include(cmake/deps.cmake)
+include(GNUInstallDirs)
+
+if(BUILD_SHARED_LIBS AND NOT DEFINED CMAKE_INSTALL_RPATH)
+  # Set the rpath to match autoconf/libtool behavior. Note this must be set
+  # before target creation.
+  set(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
+endif()
+
+# ##############################################################################
+# Options.
+if(WEBP_ENABLE_SWAP_16BIT_CSP)
+  add_definitions(-DWEBP_SWAP_16BIT_CSP=1)
+endif()
+
+if(NOT WEBP_BITTRACE STREQUAL "0")
+  add_definitions(-DBITTRACE=${WEBP_BITTRACE})
+endif()
+
+if(WEBP_UNICODE)
+  # Windows recommends setting both UNICODE and _UNICODE.
+  add_definitions(-DUNICODE -D_UNICODE)
+endif()
+
+if(MSVC AND BUILD_SHARED_LIBS)
+  add_definitions(-DWEBP_DLL)
+endif()
+
+# pkg-config variables used by *.pc.in.
+set(prefix ${CMAKE_INSTALL_PREFIX})
+set(exec_prefix "\${prefix}")
+if(IS_ABSOLUTE "${CMAKE_INSTALL_LIBDIR}")
+  set(libdir "${CMAKE_INSTALL_LIBDIR}")
+else()
+  set(libdir "\${exec_prefix}/${CMAKE_INSTALL_LIBDIR}")
+endif()
+if(IS_ABSOLUTE "${CMAKE_INSTALL_INCLUDEDIR}")
+  set(includedir "${CMAKE_INSTALL_INCLUDEDIR}")
+else()
+  set(includedir "\${prefix}/${CMAKE_INSTALL_INCLUDEDIR}")
+endif()
+set(PTHREAD_LIBS ${CMAKE_THREAD_LIBS_INIT})
+set(INSTALLED_LIBRARIES)
+
+if(MSVC)
+  # match the naming convention used by nmake
+  set(webp_libname_prefix "lib")
+  set(CMAKE_SHARED_LIBRARY_PREFIX "${webp_libname_prefix}")
+  set(CMAKE_IMPORT_LIBRARY_PREFIX "${webp_libname_prefix}")
+  set(CMAKE_STATIC_LIBRARY_PREFIX "${webp_libname_prefix}")
+endif()
+
+set(CMAKE_C_VISIBILITY_PRESET hidden)
+
+# ##############################################################################
+# Android only.
+if(ANDROID)
+  include_directories(${ANDROID_NDK}/sources/android/cpufeatures)
+  add_library(cpufeatures-webp STATIC
+              ${ANDROID_NDK}/sources/android/cpufeatures/cpu-features.c)
+  list(APPEND INSTALLED_LIBRARIES cpufeatures-webp)
+  target_link_libraries(cpufeatures-webp dl)
+  set(SHARPYUV_DEP_LIBRARIES ${SHARPYUV_DEP_LIBRARIES} cpufeatures-webp)
+  set(WEBP_DEP_LIBRARIES ${WEBP_DEP_LIBRARIES} cpufeatures-webp)
+  set(cpufeatures_include_dir ${ANDROID_NDK}/sources/android/cpufeatures)
+  set(SHARPYUV_DEP_INCLUDE_DIRS ${SHARPYUV_DEP_INCLUDE_DIRS}
+                                ${cpufeatures_include_dir})
+  set(WEBP_DEP_INCLUDE_DIRS ${WEBP_DEP_INCLUDE_DIRS} ${cpufeatures_include_dir})
+  add_definitions(-DHAVE_CPU_FEATURES_H=1)
+  set(HAVE_CPU_FEATURES_H 1)
+else()
+  set(HAVE_CPU_FEATURES_H 0)
+endif()
+
+function(configure_pkg_config FILE)
+  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/${FILE}.in"
+                 "${CMAKE_CURRENT_BINARY_DIR}/${FILE}" @ONLY)
+
+  if(HAVE_MATH_LIBRARY)
+    # MSVC doesn't have libm
+    file(READ ${CMAKE_CURRENT_BINARY_DIR}/${FILE} data)
+    string(REPLACE "-lm" "" data ${data})
+    file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/${FILE} ${data})
+  endif()
+
+  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${FILE}"
+          DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
+endfunction()
+
+# ##############################################################################
+# WebP source files. Read the Makefile.am to get the source files.
+
+# We expect the Makefiles to define the sources as defined in the first regex.
+# E.g.: libimagedec_la_SOURCES  = image_dec.c image_dec.h
+function(parse_Makefile_am FOLDER VAR SRC_REGEX)
+  file(READ ${FOLDER}/Makefile.am MAKEFILE_AM)
+  string(REGEX MATCHALL "${SRC_REGEX}_SOURCES[ ]*\\+?=[ ]+[0-9a-z\\._ ]*"
+               FILES_PER_LINE ${MAKEFILE_AM})
+  set(SRCS ${${VAR}})
+  foreach(FILES ${FILES_PER_LINE})
+    string(FIND ${FILES} "=" OFFSET)
+    math(EXPR OFFSET "${OFFSET} + 2")
+    string(SUBSTRING ${FILES} ${OFFSET} -1 FILES)
+    if(FILES)
+      string(REGEX MATCHALL "[0-9a-z\\._]+" FILES ${FILES})
+      foreach(FILE ${FILES})
+        list(APPEND SRCS ${FOLDER}/${FILE})
+      endforeach()
+    endif()
+  endforeach()
+  set(${VAR} ${SRCS} PARENT_SCOPE)
+endfunction()
+
+set(WEBP_SRC_DIR ${CMAKE_CURRENT_SOURCE_DIR}/src)
+parse_makefile_am(${WEBP_SRC_DIR}/dec "WEBP_DEC_SRCS" "")
+parse_makefile_am(${WEBP_SRC_DIR}/demux "WEBP_DEMUX_SRCS" "")
+parse_makefile_am(${WEBP_SRC_DIR}/dsp "WEBP_DSP_COMMON_SRCS" "COMMON")
+parse_makefile_am(${WEBP_SRC_DIR}/dsp "WEBP_DSP_ENC_SRCS" "ENC")
+parse_makefile_am(${WEBP_SRC_DIR}/dsp "WEBP_DSP_ENC_SRCS" "dsp_[^ ]*")
+parse_makefile_am(${WEBP_SRC_DIR}/dsp "WEBP_DSP_DEC_SRCS" "decode_[^ ]*")
+parse_makefile_am(${WEBP_SRC_DIR}/enc "WEBP_ENC_SRCS" "")
+parse_makefile_am(${WEBP_SRC_DIR}/utils "WEBP_UTILS_COMMON_SRCS" "COMMON")
+parse_makefile_am(${WEBP_SRC_DIR}/utils "WEBP_UTILS_ENC_SRCS" "ENC")
+parse_makefile_am(${WEBP_SRC_DIR}/utils "WEBP_UTILS_DEC_SRCS" "decode_[^ ]*")
+
+# Remove the files specific to SIMD we don't use.
+foreach(FILE ${WEBP_SIMD_FILES_NOT_TO_INCLUDE})
+  list(REMOVE_ITEM WEBP_DSP_ENC_SRCS ${FILE})
+  list(REMOVE_ITEM WEBP_DSP_DEC_SRCS ${FILE})
+endforeach()
+
+# Generate the config.h file.
+configure_file(${CMAKE_CURRENT_LIST_DIR}/cmake/config.h.in
+               ${CMAKE_CURRENT_BINARY_DIR}/src/webp/config.h @ONLY)
+add_definitions(-DHAVE_CONFIG_H)
+
+# Set the version numbers.
+macro(set_version FILE TARGET_NAME NAME_IN_MAKEFILE)
+  file(READ ${CMAKE_CURRENT_SOURCE_DIR}/${FILE} SOURCE_FILE)
+  string(REGEX MATCH
+               "${NAME_IN_MAKEFILE}_la_LDFLAGS[^\n]* -version-info [0-9:]+" TMP
+               ${SOURCE_FILE})
+  string(REGEX MATCH "[0-9:]+" TMP ${TMP})
+  string(REGEX REPLACE ":" " " LT_VERSION ${TMP})
+
+  # See the libtool docs for more information:
+  # https://www.gnu.org/software/libtool/manual/libtool.html#Updating-version-info
+  #
+  # c=<current>, a=<age>, r=<revision>
+  #
+  # libtool generates a .so file as .so.[c-a].a.r, while -version-info c:r:a is
+  # passed to libtool.
+  #
+  # We set FULL = [c-a].a.r and MAJOR = [c-a].
+  separate_arguments(LT_VERSION)
+  list(GET LT_VERSION 0 LT_CURRENT)
+  list(GET LT_VERSION 1 LT_REVISION)
+  list(GET LT_VERSION 2 LT_AGE)
+  math(EXPR LT_CURRENT_MINUS_AGE "${LT_CURRENT} - ${LT_AGE}")
+
+  set_target_properties(
+    ${TARGET_NAME}
+    PROPERTIES VERSION ${LT_CURRENT_MINUS_AGE}.${LT_AGE}.${LT_REVISION}
+               SOVERSION ${LT_CURRENT_MINUS_AGE})
+  if(APPLE)
+    # For compatibility, set MACHO_COMPATIBILITY_VERSION and
+    # MACHO_CURRENT_VERSION to match libtool. These properties were introduced
+    # in 3.17:
+    # https://cmake.org/cmake/help/latest/prop_tgt/MACHO_COMPATIBILITY_VERSION.html
+    math(EXPR LIBWEBP_MACHO_COMPATIBILITY_VERSION "${LT_CURRENT} + 1")
+    set_target_properties(
+      ${TARGET_NAME}
+      PROPERTIES MACHO_COMPATIBILITY_VERSION
+                 ${LIBWEBP_MACHO_COMPATIBILITY_VERSION}
+                 MACHO_CURRENT_VERSION
+                 ${LIBWEBP_MACHO_COMPATIBILITY_VERSION}.${LT_REVISION})
+  endif()
+endmacro()
+
+# ##############################################################################
+# Build the webpdecoder library.
+
+# Creates a source file with an unused stub function in $CMAKE_BINARY_DIR and
+# adds it to the specified target. Currently used only with Xcode.
+#
+# See also:
+# https://cmake.org/cmake/help/v3.18/command/add_library.html#object-libraries
+# "Some native build systems (such as Xcode) may not like targets that have only
+# object files, so consider adding at least one real source file to any target
+# that references $<TARGET_OBJECTS:objlib>."
+function(libwebp_add_stub_file TARGET)
+  set(stub_source_dir "${CMAKE_BINARY_DIR}")
+  set(stub_source_file "${stub_source_dir}/libwebp_${TARGET}_stub.c")
+  set(stub_source_code
+      "// Generated file. DO NOT EDIT!\n"
+      "// C source file created for target ${TARGET}.\n"
+      "void libwebp_${TARGET}_stub_function(void)\;\n"
+      "void libwebp_${TARGET}_stub_function(void) {}\n")
+  file(WRITE "${stub_source_file}" ${stub_source_code})
+
+  target_sources(${TARGET} PRIVATE ${stub_source_file})
+endfunction()
+
+parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv "WEBP_SHARPYUV_SRCS" "")
+add_library(sharpyuv ${WEBP_SHARPYUV_SRCS})
+target_link_libraries(sharpyuv ${SHARPYUV_DEP_LIBRARIES})
+set_version(sharpyuv/Makefile.am sharpyuv sharpyuv)
+target_include_directories(
+  sharpyuv PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+                   ${CMAKE_CURRENT_SOURCE_DIR}/src)
+set_target_properties(
+  sharpyuv
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv/sharpyuv.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv/sharpyuv_csp.h")
+configure_pkg_config("sharpyuv/libsharpyuv.pc")
+install(
+  TARGETS sharpyuv
+  EXPORT ${PROJECT_NAME}Targets
+  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/webp/sharpyuv
+  INCLUDES
+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+  ${CMAKE_INSTALL_INCLUDEDIR}/webp
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+
+if(MSVC)
+  # avoid security warnings for e.g., fopen() used in the examples.
+  add_definitions(-D_CRT_SECURE_NO_WARNINGS)
+else()
+  add_compile_options(-Wall)
+endif()
+include_directories(${WEBP_DEP_INCLUDE_DIRS})
+add_library(webpdecode OBJECT ${WEBP_DEC_SRCS})
+target_include_directories(webpdecode PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                              ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webpdspdecode OBJECT ${WEBP_DSP_COMMON_SRCS} ${WEBP_DSP_DEC_SRCS})
+target_include_directories(webpdspdecode PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                                 ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webputilsdecode OBJECT ${WEBP_UTILS_COMMON_SRCS}
+                                   ${WEBP_UTILS_DEC_SRCS})
+target_include_directories(webputilsdecode PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                                   ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(
+  webpdecoder $<TARGET_OBJECTS:webpdecode> $<TARGET_OBJECTS:webpdspdecode>
+              $<TARGET_OBJECTS:webputilsdecode>)
+if(XCODE)
+  libwebp_add_stub_file(webpdecoder)
+endif()
+target_link_libraries(webpdecoder ${WEBP_DEP_LIBRARIES})
+target_include_directories(
+  webpdecoder PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+  INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+            $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
+set_target_properties(
+  webpdecoder
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
+
+configure_pkg_config("src/libwebpdecoder.pc")
+
+# Build the webp library.
+add_library(webpencode OBJECT ${WEBP_ENC_SRCS})
+target_include_directories(
+  webpencode PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+                     ${CMAKE_CURRENT_SOURCE_DIR}/src)
+add_library(webpdsp OBJECT ${WEBP_DSP_COMMON_SRCS} ${WEBP_DSP_DEC_SRCS}
+                           ${WEBP_DSP_ENC_SRCS})
+target_include_directories(webpdsp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                           ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webputils OBJECT ${WEBP_UTILS_COMMON_SRCS} ${WEBP_UTILS_DEC_SRCS}
+                             ${WEBP_UTILS_ENC_SRCS})
+target_include_directories(webputils PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                             ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webp $<TARGET_OBJECTS:webpdecode> $<TARGET_OBJECTS:webpdsp>
+                 $<TARGET_OBJECTS:webpencode> $<TARGET_OBJECTS:webputils>)
+target_link_libraries(webp sharpyuv)
+if(XCODE)
+  libwebp_add_stub_file(webp)
+endif()
+target_link_libraries(webp ${WEBP_DEP_LIBRARIES})
+target_include_directories(
+  webp PRIVATE ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}
+  PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>
+         $<INSTALL_INTERFACE:include>)
+set_target_properties(
+  webp
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/encode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
+
+# Make sure the OBJECT libraries are built with position independent code (it is
+# not ON by default).
+set_target_properties(webpdecode webpdspdecode webputilsdecode webpencode
+                      webpdsp webputils PROPERTIES POSITION_INDEPENDENT_CODE ON)
+configure_pkg_config("src/libwebp.pc")
+
+# Build the webp demux library.
+add_library(webpdemux ${WEBP_DEMUX_SRCS})
+target_link_libraries(webpdemux webp)
+target_include_directories(
+  webpdemux PRIVATE ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}
+  PUBLIC $<INSTALL_INTERFACE:include>)
+set_target_properties(
+  webpdemux
+  PROPERTIES
+    PUBLIC_HEADER
+    "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/demux.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux_types.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
+
+configure_pkg_config("src/demux/libwebpdemux.pc")
+
+set_version(src/Makefile.am webp webp)
+set_version(src/Makefile.am webpdecoder webpdecoder)
+set_version(src/demux/Makefile.am webpdemux webpdemux)
+file(READ ${CMAKE_CURRENT_SOURCE_DIR}/configure.ac CONFIGURE_FILE)
+string(REGEX MATCH "AC_INIT\\([^\n]*\\[[0-9\\.]+\\]" TMP ${CONFIGURE_FILE})
+string(REGEX MATCH "[0-9\\.]+" PROJECT_VERSION ${TMP})
+
+# Define the libraries to install.
+list(APPEND INSTALLED_LIBRARIES webpdecoder webp webpdemux)
+
+# Deal with SIMD. Change the compile flags for SIMD files we use.
+list(LENGTH WEBP_SIMD_FILES_TO_INCLUDE WEBP_SIMD_FILES_TO_INCLUDE_LENGTH)
+math(EXPR WEBP_SIMD_FILES_TO_INCLUDE_RANGE
+     "${WEBP_SIMD_FILES_TO_INCLUDE_LENGTH}-1")
+
+foreach(I_FILE RANGE ${WEBP_SIMD_FILES_TO_INCLUDE_RANGE})
+  list(GET WEBP_SIMD_FILES_TO_INCLUDE ${I_FILE} FILE)
+  list(GET WEBP_SIMD_FLAGS_TO_INCLUDE ${I_FILE} SIMD_COMPILE_FLAG)
+  set_source_files_properties(${FILE} PROPERTIES COMPILE_FLAGS
+                                                 ${SIMD_COMPILE_FLAG})
+endforeach()
+
+if(NOT WEBP_BUILD_LIBWEBPMUX)
+  set(WEBP_BUILD_GIF2WEBP OFF)
+  set(WEBP_BUILD_IMG2WEBP OFF)
+  set(WEBP_BUILD_WEBPMUX OFF)
+endif()
+
+if(WEBP_BUILD_GIF2WEBP AND NOT GIF_FOUND)
+  set(WEBP_BUILD_GIF2WEBP OFF)
+endif()
+
+if(WEBP_BUILD_ANIM_UTILS AND NOT GIF_FOUND)
+  set(WEBP_BUILD_ANIM_UTILS OFF)
+endif()
+
+# Build the executables if asked for.
+if(WEBP_BUILD_ANIM_UTILS
+   OR WEBP_BUILD_CWEBP
+   OR WEBP_BUILD_DWEBP
+   OR WEBP_BUILD_GIF2WEBP
+   OR WEBP_BUILD_IMG2WEBP
+   OR WEBP_BUILD_VWEBP
+   OR WEBP_BUILD_WEBPMUX
+   OR WEBP_BUILD_WEBPINFO)
+  # Example utility library.
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "EXAMPLEUTIL_SRCS"
+                    "example_util_[^ ]*")
+  list(APPEND EXAMPLEUTIL_SRCS ${CMAKE_CURRENT_SOURCE_DIR}/examples/stopwatch.h)
+  add_library(exampleutil STATIC ${EXAMPLEUTIL_SRCS})
+  target_include_directories(
+    exampleutil PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>)
+
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/imageio "IMAGEIOUTILS_SRCS"
+                    "imageio_util_[^ ]*")
+  add_library(imageioutil STATIC ${IMAGEIOUTILS_SRCS})
+  target_link_libraries(imageioutil webp)
+  target_link_libraries(exampleutil imageioutil)
+
+  # Image-decoding utility library.
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/imageio "IMAGEDEC_SRCS"
+                    "imagedec_[^ ]*")
+  add_library(imagedec STATIC ${IMAGEDEC_SRCS})
+  target_link_libraries(imagedec imageioutil webpdemux webp
+                        ${WEBP_DEP_IMG_LIBRARIES})
+
+  # Image-encoding utility library.
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/imageio "IMAGEENC_SRCS"
+                    "imageenc_[^ ]*")
+  add_library(imageenc STATIC ${IMAGEENC_SRCS})
+  target_link_libraries(imageenc imageioutil webp)
+
+  set_property(
+    TARGET exampleutil imageioutil imagedec imageenc
+    PROPERTY INCLUDE_DIRECTORIES ${CMAKE_CURRENT_SOURCE_DIR}/src
+             ${CMAKE_CURRENT_BINARY_DIR}/src)
+endif()
+
+if(WEBP_BUILD_DWEBP)
+  # dwebp
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "DWEBP_SRCS" "dwebp")
+  add_executable(dwebp ${DWEBP_SRCS})
+  target_link_libraries(dwebp exampleutil imagedec imageenc)
+  target_include_directories(dwebp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+  install(TARGETS dwebp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(WEBP_BUILD_CWEBP)
+  # cwebp
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "CWEBP_SRCS" "cwebp")
+  add_executable(cwebp ${CWEBP_SRCS})
+  target_link_libraries(cwebp exampleutil imagedec webp)
+  target_include_directories(cwebp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src
+                                           ${CMAKE_CURRENT_SOURCE_DIR})
+  install(TARGETS cwebp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(WEBP_BUILD_LIBWEBPMUX)
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/src/mux "WEBP_MUX_SRCS" "")
+  add_library(libwebpmux ${WEBP_MUX_SRCS})
+  target_link_libraries(libwebpmux webp)
+  target_include_directories(libwebpmux PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                                ${CMAKE_CURRENT_SOURCE_DIR})
+  set_version(src/mux/Makefile.am libwebpmux webpmux)
+  set_target_properties(
+    libwebpmux
+    PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux_types.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h;")
+  set_target_properties(libwebpmux PROPERTIES OUTPUT_NAME webpmux)
+  list(APPEND INSTALLED_LIBRARIES libwebpmux)
+  configure_pkg_config("src/mux/libwebpmux.pc")
+endif()
+
+if(WEBP_BUILD_GIF2WEBP)
+  # gif2webp
+  include_directories(${WEBP_DEP_GIF_INCLUDE_DIRS})
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "GIF2WEBP_SRCS"
+                    "gif2webp")
+  add_executable(gif2webp ${GIF2WEBP_SRCS})
+  target_link_libraries(gif2webp exampleutil imageioutil webp libwebpmux
+                        ${WEBP_DEP_GIF_LIBRARIES})
+  target_include_directories(gif2webp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+  install(TARGETS gif2webp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(WEBP_BUILD_IMG2WEBP)
+  # img2webp
+  include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS})
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "IMG2WEBP_SRCS"
+                    "img2webp")
+  add_executable(img2webp ${IMG2WEBP_SRCS})
+  target_link_libraries(img2webp exampleutil imagedec imageioutil webp
+                        libwebpmux)
+  target_include_directories(img2webp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src
+                                              ${CMAKE_CURRENT_SOURCE_DIR})
+  install(TARGETS img2webp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(WEBP_BUILD_VWEBP)
+  # vwebp
+  find_package(GLUT)
+  if(GLUT_FOUND)
+    include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS})
+    parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "VWEBP_SRCS" "vwebp")
+    add_executable(vwebp ${VWEBP_SRCS})
+    target_link_libraries(
+      vwebp
+      ${OPENGL_LIBRARIES}
+      exampleutil
+      GLUT::GLUT
+      imageioutil
+      webp
+      webpdemux)
+    target_include_directories(
+      vwebp PRIVATE ${GLUT_INCLUDE_DIR} ${CMAKE_CURRENT_BINARY_DIR}/src
+                    ${OPENGL_INCLUDE_DIR})
+    install(TARGETS vwebp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+    if(${CMAKE_SYSTEM_NAME} STREQUAL "Darwin")
+      check_c_compiler_flag("-Wno-deprecated-declarations" HAS_NO_DEPRECATED)
+      if(HAS_NO_DEPRECATED)
+        target_compile_options(vwebp PRIVATE "-Wno-deprecated-declarations")
+      endif()
+    endif()
+  endif()
+endif()
+
+if(WEBP_BUILD_WEBPINFO)
+  # webpinfo
+  include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS})
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "WEBPINFO_SRCS"
+                    "webpinfo")
+  add_executable(webpinfo ${WEBPINFO_SRCS})
+  target_link_libraries(webpinfo exampleutil imageioutil)
+  target_include_directories(webpinfo PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src
+                                              ${CMAKE_CURRENT_SOURCE_DIR}/src)
+  install(TARGETS webpinfo RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(WEBP_BUILD_WEBPMUX)
+  # webpmux
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "WEBPMUX_SRCS"
+                    "webpmux")
+  add_executable(webpmux ${WEBPMUX_SRCS})
+  target_link_libraries(webpmux exampleutil imageioutil libwebpmux webp)
+  target_include_directories(webpmux PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+  install(TARGETS webpmux RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+endif()
+
+if(WEBP_BUILD_EXTRAS)
+  set(EXTRAS_MAKEFILE "${CMAKE_CURRENT_SOURCE_DIR}/extras")
+  parse_makefile_am(${EXTRAS_MAKEFILE} "WEBP_EXTRAS_SRCS" "libwebpextras_la")
+  parse_makefile_am(${EXTRAS_MAKEFILE} "GET_DISTO_SRCS" "get_disto")
+  parse_makefile_am(${EXTRAS_MAKEFILE} "WEBP_QUALITY_SRCS" "webp_quality")
+  parse_makefile_am(${EXTRAS_MAKEFILE} "VWEBP_SDL_SRCS" "vwebp_sdl")
+
+  # libextras
+  add_library(extras STATIC ${WEBP_EXTRAS_SRCS})
+  target_include_directories(
+    extras PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+                   ${CMAKE_CURRENT_SOURCE_DIR}/src)
+
+  # get_disto
+  add_executable(get_disto ${GET_DISTO_SRCS})
+  target_link_libraries(get_disto imagedec)
+  target_include_directories(get_disto PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+                                               ${CMAKE_CURRENT_BINARY_DIR}/src)
+
+  # webp_quality
+  add_executable(webp_quality ${WEBP_QUALITY_SRCS})
+  target_link_libraries(webp_quality exampleutil imagedec extras)
+  target_include_directories(webp_quality PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+                                                  ${CMAKE_CURRENT_BINARY_DIR})
+
+  # vwebp_sdl
+  find_package(SDL)
+  if(WEBP_BUILD_VWEBP AND SDL_FOUND)
+    add_executable(vwebp_sdl ${VWEBP_SDL_SRCS})
+    target_link_libraries(vwebp_sdl ${SDL_LIBRARY} imageioutil webp)
+    target_include_directories(
+      vwebp_sdl PRIVATE ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}
+                        ${CMAKE_CURRENT_BINARY_DIR}/src ${SDL_INCLUDE_DIR})
+    set(WEBP_HAVE_SDL 1)
+    target_compile_definitions(vwebp_sdl PUBLIC WEBP_HAVE_SDL)
+  endif()
+endif()
+
+if(WEBP_BUILD_WEBP_JS)
+  # The default stack size changed from 5MB to 64KB in 3.1.27. See
+  # https://crbug.com/webp/614.
+  if(EMSCRIPTEN_VERSION VERSION_GREATER_EQUAL "3.1.27")
+    # TOTAL_STACK size was renamed to STACK_SIZE in 3.1.27. The old name was
+    # kept for compatibility, but prefer the new one in case it is removed in
+    # the future.
+    set(emscripten_stack_size "-sSTACK_SIZE=5MB")
+  else()
+    set(emscripten_stack_size "-sTOTAL_STACK=5MB")
+  endif()
+  # wasm2js does not support SIMD.
+  if(NOT WEBP_ENABLE_SIMD)
+    # JavaScript version
+    add_executable(webp_js ${CMAKE_CURRENT_SOURCE_DIR}/extras/webp_to_sdl.c)
+    target_link_libraries(webp_js webpdecoder SDL)
+    target_include_directories(webp_js PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
+    set(WEBP_HAVE_SDL 1)
+    set_target_properties(
+      webp_js
+      PROPERTIES LINK_FLAGS "-sWASM=0 ${emscripten_stack_size} \
+         -sEXPORTED_FUNCTIONS=_WebPToSDL -sINVOKE_RUN=0 \
+         -sEXPORTED_RUNTIME_METHODS=cwrap")
+    set_target_properties(webp_js PROPERTIES OUTPUT_NAME webp)
+    target_compile_definitions(webp_js PUBLIC EMSCRIPTEN WEBP_HAVE_SDL)
+  endif()
+
+  # WASM version
+  add_executable(webp_wasm ${CMAKE_CURRENT_SOURCE_DIR}/extras/webp_to_sdl.c)
+  target_link_libraries(webp_wasm webpdecoder SDL)
+  target_include_directories(webp_wasm PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
+  set_target_properties(
+    webp_wasm
+    PROPERTIES LINK_FLAGS "-sWASM=1 ${emscripten_stack_size} \
+       -sEXPORTED_FUNCTIONS=_WebPToSDL -sINVOKE_RUN=0 \
+       -sEXPORTED_RUNTIME_METHODS=cwrap")
+  target_compile_definitions(webp_wasm PUBLIC EMSCRIPTEN WEBP_HAVE_SDL)
+
+  target_compile_definitions(webpdspdecode PUBLIC EMSCRIPTEN)
+endif()
+
+if(WEBP_BUILD_ANIM_UTILS)
+  # anim_diff
+  include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS} ${WEBP_DEP_GIF_INCLUDE_DIRS})
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "ANIM_DIFF_SRCS"
+                    "anim_diff")
+  add_executable(anim_diff ${ANIM_DIFF_SRCS})
+  target_link_libraries(
+    anim_diff
+    exampleutil
+    imagedec
+    imageenc
+    imageioutil
+    webp
+    webpdemux
+    ${WEBP_DEP_GIF_LIBRARIES})
+  target_include_directories(anim_diff PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+
+  # anim_dump
+  include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS} ${WEBP_DEP_GIF_INCLUDE_DIRS})
+  parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "ANIM_DUMP_SRCS"
+                    "anim_dump")
+  add_executable(anim_dump ${ANIM_DUMP_SRCS})
+  target_link_libraries(
+    anim_dump
+    exampleutil
+    imagedec
+    imageenc
+    imageioutil
+    webp
+    webpdemux
+    ${WEBP_DEP_GIF_LIBRARIES})
+  target_include_directories(anim_dump PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+endif()
+
+# Install the different headers and libraries.
+install(
+  TARGETS ${INSTALLED_LIBRARIES}
+  EXPORT ${PROJECT_NAME}Targets
+  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/webp
+  INCLUDES
+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+set(ConfigPackageLocation ${CMAKE_INSTALL_DATADIR}/${PROJECT_NAME}/cmake/)
+install(EXPORT ${PROJECT_NAME}Targets NAMESPACE ${PROJECT_NAME}::
+        DESTINATION ${ConfigPackageLocation})
+
+# Create the CMake version file.
+include(CMakePackageConfigHelpers)
+write_basic_package_version_file(
+  "${CMAKE_CURRENT_BINARY_DIR}/WebPConfigVersion.cmake"
+  VERSION ${PACKAGE_VERSION} COMPATIBILITY AnyNewerVersion)
+
+# Create the Config file.
+include(CMakePackageConfigHelpers)
+# Fix libwebpmux reference. The target name libwebpmux is used for compatibility
+# purposes, but the library mentioned in WebPConfig.cmake should be the
+# unprefixed version. Note string(...) can be replaced with list(TRANSFORM ...)
+# if cmake_minimum_required is >= 3.12.
+string(REGEX REPLACE "libwebpmux" "webpmux" INSTALLED_LIBRARIES
+                     "${INSTALLED_LIBRARIES}")
+
+if(MSVC)
+  # For compatibility with nmake, MSVC builds use a custom prefix (lib) that
+  # needs to be included in the library name.
+  string(REGEX REPLACE "[A-Za-z0-9_]+" "${CMAKE_STATIC_LIBRARY_PREFIX}\\0"
+                       INSTALLED_LIBRARIES "${INSTALLED_LIBRARIES}")
+endif()
+
+configure_package_config_file(
+  ${CMAKE_CURRENT_SOURCE_DIR}/cmake/WebPConfig.cmake.in
+  ${CMAKE_CURRENT_BINARY_DIR}/WebPConfig.cmake
+  INSTALL_DESTINATION ${ConfigPackageLocation}
+  PATH_VARS CMAKE_INSTALL_INCLUDEDIR)
+
+# Install the generated CMake files.
+install(FILES "${CMAKE_CURRENT_BINARY_DIR}/WebPConfigVersion.cmake"
+              "${CMAKE_CURRENT_BINARY_DIR}/WebPConfig.cmake"
+        DESTINATION ${ConfigPackageLocation})
+
+# Install the man pages.
+set(MAN_PAGES
+    cwebp.1
+    dwebp.1
+    gif2webp.1
+    img2webp.1
+    vwebp.1
+    webpmux.1
+    webpinfo.1)
+set(EXEC_BUILDS
+    "CWEBP"
+    "DWEBP"
+    "GIF2WEBP"
+    "IMG2WEBP"
+    "VWEBP"
+    "WEBPMUX"
+    "WEBPINFO")
+list(LENGTH MAN_PAGES MAN_PAGES_LENGTH)
+math(EXPR MAN_PAGES_RANGE "${MAN_PAGES_LENGTH} - 1")
+
+foreach(I_MAN RANGE ${MAN_PAGES_RANGE})
+  list(GET EXEC_BUILDS ${I_MAN} EXEC_BUILD)
+  if(WEBP_BUILD_${EXEC_BUILD})
+    list(GET MAN_PAGES ${I_MAN} MAN_PAGE)
+    install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/man/${MAN_PAGE}
+            DESTINATION ${CMAKE_INSTALL_MANDIR}/man1 COMPONENT doc)
+  endif()
+endforeach()
--- a/external/libwebp/libwebp/CONTRIBUTING.md
+++ b/external/libwebp/libwebp/CONTRIBUTING.md
@@ -0,0 +1,78 @@
+# How to Contribute
+
+We'd love to accept your patches and contributions to this project. There are
+just a few small guidelines you need to follow.
+
+## Contributor License Agreement
+
+Contributions to this project must be accompanied by a Contributor License
+Agreement. You (or your employer) retain the copyright to your contribution;
+this simply gives us permission to use and redistribute your contributions as
+part of the project. Head over to <https://cla.developers.google.com/> to see
+your current agreements on file or to sign a new one.
+
+You generally only need to submit a CLA once, so if you've already submitted one
+(even if it was for a different project), you probably don't need to do it
+again.
+
+## Code reviews
+
+All submissions, including submissions by project members, require review. We
+use a [Gerrit](https://www.gerritcodereview.com) instance hosted at
+https://chromium-review.googlesource.com for this purpose.
+
+## Sending patches
+
+The basic git workflow for modifying libwebp code and sending for review is:
+
+1.  Get the latest version of the repository locally:
+
+    ```sh
+    git clone https://chromium.googlesource.com/webm/libwebp && cd libwebp
+    ```
+
+2.  Copy the commit-msg script into ./git/hooks (this will add an ID to all of
+    your commits):
+
+    ```sh
+    curl -Lo .git/hooks/commit-msg https://chromium-review.googlesource.com/tools/hooks/commit-msg && chmod u+x .git/hooks/commit-msg
+    ```
+
+3.  Modify the local copy of libwebp. Make sure the code
+    [builds successfully](https://chromium.googlesource.com/webm/libwebp/+/HEAD/doc/building.md#cmake).
+
+4.  Choose a short and representative commit message:
+
+    ```sh
+    git commit -a -m "Set commit message here"
+    ```
+
+5.  Send the patch for review:
+
+    ```sh
+    git push https://chromium-review.googlesource.com/webm/libwebp HEAD:refs/for/main
+    ```
+
+    Go to https://chromium-review.googlesource.com to view your patch and
+    request a review from the maintainers.
+
+See the
+[WebM Project page](https://www.webmproject.org/code/contribute/submitting-patches/)
+for additional details.
+
+## Code Style
+
+The C code style is based on the
+[Google C++ Style Guide](https://google.github.io/styleguide/cppguide.html) and
+`clang-format --style=Google`, though this project doesn't use the tool to
+enforce the formatting.
+
+CMake files are formatted with
+[cmake-format](https://cmake-format.readthedocs.io/en/latest/). `cmake-format
+-i` can be used to format individual files, it will use the settings from
+`.cmake-format.py`.
+
+## Community Guidelines
+
+This project follows
+[Google's Open Source Community Guidelines](https://opensource.google.com/conduct/).
--- a/external/libwebp/libwebp/COPYING
+++ b/external/libwebp/libwebp/COPYING
@@ -0,0 +1,30 @@
+Copyright (c) 2010, Google Inc. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+  * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+  * Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in
+    the documentation and/or other materials provided with the
+    distribution.
+
+  * Neither the name of Google nor the names of its contributors may
+    be used to endorse or promote products derived from this software
+    without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
--- a/external/libwebp/libwebp/ChangeLog
+++ b/external/libwebp/libwebp/ChangeLog
--- a/external/libwebp/libwebp/Makefile.am
+++ b/external/libwebp/libwebp/Makefile.am
@@ -0,0 +1,9 @@
+ACLOCAL_AMFLAGS = -I m4
+SUBDIRS = sharpyuv src imageio man
+EXTRA_DIST = COPYING autogen.sh
+
+if BUILD_EXTRAS
+  SUBDIRS += extras
+endif
+
+SUBDIRS += examples
--- a/external/libwebp/libwebp/Makefile.vc
+++ b/external/libwebp/libwebp/Makefile.vc
@@ -0,0 +1,528 @@
+#
+# Stem for static libs and DLLs
+#
+LIBWEBPDECODER_BASENAME = libwebpdecoder
+LIBWEBP_BASENAME = libwebp
+LIBWEBPMUX_BASENAME = libwebpmux
+LIBWEBPDEMUX_BASENAME = libwebpdemux
+LIBSHARPYUV_BASENAME = libsharpyuv
+
+!IFNDEF ARCH
+!IF ! [ cl 2>&1 | find "x86" > NUL ]
+ARCH = x86
+!ELSE IF ! [ cl 2>&1 | find "x64" > NUL ]
+ARCH = x64
+!ELSE IF ! [ cl 2>&1 | find "ARM" > NUL ]
+ARCH = ARM
+!ELSE
+!ERROR Unable to auto-detect toolchain architecture! \
+If cl.exe is in your PATH rerun nmake with ARCH=<arch>.
+!ENDIF
+!ENDIF
+
+!IF "$(ARCH)" == "x86"
+PLATFORM_LDFLAGS = /SAFESEH
+!ENDIF
+
+#############################################################
+## Nothing more to do below this line!
+
+NOLOGO     = /nologo
+CCNODBG    = cl.exe $(NOLOGO) /O2 /DNDEBUG
+CCDEBUG    = cl.exe $(NOLOGO) /Od /Zi /D_DEBUG /RTC1
+CFLAGS     = /I. /Isrc $(NOLOGO) /W3 /EHsc /c
+CFLAGS     = $(CFLAGS) /DWIN32 /D_CRT_SECURE_NO_WARNINGS /DWIN32_LEAN_AND_MEAN
+LDFLAGS    = /LARGEADDRESSAWARE /MANIFEST:EMBED /NXCOMPAT /DYNAMICBASE
+LDFLAGS    = $(LDFLAGS) $(PLATFORM_LDFLAGS)
+LNKDLL     = link.exe /DLL $(NOLOGO)
+LNKEXE     = link.exe $(NOLOGO)
+LNKLIB     = lib.exe $(NOLOGO)
+RCNODBG    = rc.exe $(NOLOGO) /l"0x0409"  # 0x409 = U.S. English
+RCDEBUG    = $(RCNODBG) /D_DEBUG
+
+!IF "$(ARCH)" == "ARM"
+CFLAGS = $(CFLAGS) /DWINAPI_FAMILY=WINAPI_FAMILY_PHONE_APP /DWEBP_USE_THREAD
+!ELSE
+CFLAGS = $(CFLAGS) /DHAVE_WINCODEC_H /DWEBP_USE_THREAD
+!ENDIF
+
+CFGSET     = FALSE
+!IF "$(OBJDIR)" == ""
+OUTDIR = ..\obj\
+!ELSE
+OUTDIR = $(OBJDIR)
+!ENDIF
+
+##############################################################
+# Runtime library configuration
+!IF "$(RTLIBCFG)" == "static"
+RTLIB  = /MT
+RTLIBD = /MTd
+!ELSE IF "$(RTLIBCFG)" == "legacy"
+RTLIBCFG = static
+RTLIB  = /MT
+RTLIBD = /MTd
+CFLAGS = $(CFLAGS) /GS- /arch:IA32
+!ELSE
+RTLIB   = /MD
+RTLIBD  = /MDd
+!ENDIF
+DIRBASE = $(OUTDIR)\$(CFG)\$(ARCH)
+DIROBJ = $(DIRBASE)\obj
+DIRLIB = $(DIRBASE)\lib
+DIRINC = $(DIRBASE)\include
+DIRBIN = $(DIRBASE)\bin
+LIBWEBP_PDBNAME = $(DIROBJ)\$(LIBWEBP_BASENAME).pdb
+OUTPUT_DIRS = $(DIRBIN) $(DIRINC) $(DIRLIB) \
+              $(DIROBJ)\dec \
+              $(DIROBJ)\demux \
+              $(DIROBJ)\dsp \
+              $(DIROBJ)\enc \
+              $(DIROBJ)\examples \
+              $(DIROBJ)\extras \
+              $(DIROBJ)\imageio \
+              $(DIROBJ)\mux \
+              $(DIROBJ)\sharpyuv \
+              $(DIROBJ)\utils \
+
+# Target configuration
+!IF "$(CFG)" == "release-static"
+CC             = $(CCNODBG)
+STATICLIBBUILD = TRUE
+!ELSE IF "$(CFG)" == "debug-static"
+CC             = $(CCDEBUG)
+RTLIB          = $(RTLIBD)
+STATICLIBBUILD = TRUE
+LIBWEBPDECODER_BASENAME = $(LIBWEBPDECODER_BASENAME)_debug
+LIBWEBP_BASENAME = $(LIBWEBP_BASENAME)_debug
+LIBWEBPMUX_BASENAME = $(LIBWEBPMUX_BASENAME)_debug
+LIBWEBPDEMUX_BASENAME = $(LIBWEBPDEMUX_BASENAME)_debug
+LIBSHARPYUV_BASENAME = $(LIBSHARPYUV_BASENAME)_debug
+!ELSE IF "$(CFG)" == "release-dynamic"
+CC        = $(CCNODBG)
+RC        = $(RCNODBG)
+DLLBUILD  = TRUE
+!ELSE IF "$(CFG)" == "debug-dynamic"
+CC        = $(CCDEBUG)
+RC        = $(RCDEBUG)
+RTLIB     = $(RTLIBD)
+DLLBUILD  = TRUE
+LIBWEBPDECODER_BASENAME = $(LIBWEBPDECODER_BASENAME)_debug
+LIBWEBP_BASENAME = $(LIBWEBP_BASENAME)_debug
+LIBWEBPMUX_BASENAME = $(LIBWEBPMUX_BASENAME)_debug
+LIBWEBPDEMUX_BASENAME = $(LIBWEBPDEMUX_BASENAME)_debug
+LIBSHARPYUV_BASENAME = $(LIBSHARPYUV_BASENAME)_debug
+!ENDIF
+
+!IF "$(STATICLIBBUILD)" == "TRUE"
+CC     = $(CC) $(RTLIB)
+CFGSET = TRUE
+LIBWEBPDECODER = $(DIRLIB)\$(LIBWEBPDECODER_BASENAME).lib
+LIBWEBP = $(DIRLIB)\$(LIBWEBP_BASENAME).lib
+LIBWEBPMUX = $(DIRLIB)\$(LIBWEBPMUX_BASENAME).lib
+LIBWEBPDEMUX = $(DIRLIB)\$(LIBWEBPDEMUX_BASENAME).lib
+LIBSHARPYUV = $(DIRLIB)\$(LIBSHARPYUV_BASENAME).lib
+!ELSE IF "$(DLLBUILD)" == "TRUE"
+CC     = $(CC) /I$(DIROBJ) $(RTLIB) /DWEBP_DLL
+LIBWEBPDECODER = $(DIRLIB)\$(LIBWEBPDECODER_BASENAME)_dll.lib
+LIBWEBP = $(DIRLIB)\$(LIBWEBP_BASENAME)_dll.lib
+LIBWEBPMUX = $(DIRLIB)\$(LIBWEBPMUX_BASENAME)_dll.lib
+LIBWEBPDEMUX = $(DIRLIB)\$(LIBWEBPDEMUX_BASENAME)_dll.lib
+LIBSHARPYUV = $(DIRLIB)\$(LIBSHARPYUV_BASENAME)_dll.lib
+LIBWEBP_PDBNAME = $(DIROBJ)\$(LIBWEBP_BASENAME)_dll.pdb
+CFGSET = TRUE
+!ENDIF
+
+!IF "$(UNICODE)" == "1"
+CFLAGS = $(CFLAGS) /D_UNICODE /DUNICODE
+!ENDIF
+
+#######################
+# Usage
+#
+!IF "$(CFGSET)" == "FALSE"
+!MESSAGE Usage: nmake /f Makefile.vc [CFG=<config>]
+!MESSAGE .          [OBJDIR=<path>] [RTLIBCFG=<rtlib>] [UNICODE=1] [<target>]
+!MESSAGE
+!MESSAGE where <config> is one of:
+!MESSAGE -  release-static                - release static library
+!MESSAGE -  debug-static                  - debug static library
+!MESSAGE -  release-dynamic               - release dynamic link library (DLL)
+!MESSAGE -  debug-dynamic                 - debug dynamic link library (DLL)
+!MESSAGE
+!MESSAGE <target> may be:
+!MESSAGE -  clean                         - perform a clean for CFG
+!MESSAGE -  experimental                  - build CFG with experimental
+!MESSAGE .                                  features enabled.
+!MESSAGE - (empty)                        - build libwebp-based targets for CFG
+!MESSAGE - all                            - build (de)mux-based targets for CFG
+!MESSAGE - gif2webp                       - requires libgif & >= VS2013
+!MESSAGE - anim_diff                      - requires libgif & >= VS2013
+!MESSAGE - anim_dump
+!MESSAGE
+!MESSAGE RTLIBCFG controls the runtime library linkage - 'static' or 'dynamic'.
+!MESSAGE   'legacy' will produce a Windows 2000 compatible library.
+!MESSAGE OBJDIR is the path where you like to build (obj, bins, etc.),
+!MESSAGE   defaults to ..\obj
+
+!IF "$(CFG)" != ""
+!MESSAGE
+!ERROR please choose a valid configuration instead of "$(CFG)"
+!ENDIF
+!ENDIF
+
+#######################
+# Rules
+#
+!IF "$(CFGSET)" == "TRUE"
+# A config was provided, so the library can be built.
+#
+
+SHARPYUV_OBJS = \
+    $(DIROBJ)\sharpyuv\sharpyuv.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_cpu.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_csp.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_dsp.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_gamma.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_neon.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_sse2.obj \
+
+DEC_OBJS = \
+    $(DIROBJ)\dec\alpha_dec.obj \
+    $(DIROBJ)\dec\buffer_dec.obj \
+    $(DIROBJ)\dec\frame_dec.obj \
+    $(DIROBJ)\dec\idec_dec.obj \
+    $(DIROBJ)\dec\io_dec.obj \
+    $(DIROBJ)\dec\quant_dec.obj \
+    $(DIROBJ)\dec\tree_dec.obj \
+    $(DIROBJ)\dec\vp8_dec.obj \
+    $(DIROBJ)\dec\vp8l_dec.obj \
+    $(DIROBJ)\dec\webp_dec.obj \
+
+DEMUX_OBJS = \
+    $(DIROBJ)\demux\anim_decode.obj \
+    $(DIROBJ)\demux\demux.obj \
+
+DSP_DEC_OBJS = \
+    $(DIROBJ)\dsp\alpha_processing.obj \
+    $(DIROBJ)\dsp\alpha_processing_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\alpha_processing_neon.obj \
+    $(DIROBJ)\dsp\alpha_processing_sse2.obj \
+    $(DIROBJ)\dsp\alpha_processing_sse41.obj \
+    $(DIROBJ)\dsp\cpu.obj \
+    $(DIROBJ)\dsp\dec.obj \
+    $(DIROBJ)\dsp\dec_clip_tables.obj \
+    $(DIROBJ)\dsp\dec_mips32.obj \
+    $(DIROBJ)\dsp\dec_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\dec_msa.obj \
+    $(DIROBJ)\dsp\dec_neon.obj \
+    $(DIROBJ)\dsp\dec_sse2.obj \
+    $(DIROBJ)\dsp\dec_sse41.obj \
+    $(DIROBJ)\dsp\filters.obj \
+    $(DIROBJ)\dsp\filters_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\filters_msa.obj \
+    $(DIROBJ)\dsp\filters_neon.obj \
+    $(DIROBJ)\dsp\filters_sse2.obj \
+    $(DIROBJ)\dsp\lossless.obj \
+    $(DIROBJ)\dsp\lossless_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\lossless_msa.obj \
+    $(DIROBJ)\dsp\lossless_neon.obj \
+    $(DIROBJ)\dsp\lossless_sse2.obj \
+    $(DIROBJ)\dsp\lossless_sse41.obj \
+    $(DIROBJ)\dsp\rescaler.obj \
+    $(DIROBJ)\dsp\rescaler_mips32.obj \
+    $(DIROBJ)\dsp\rescaler_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\rescaler_msa.obj \
+    $(DIROBJ)\dsp\rescaler_neon.obj \
+    $(DIROBJ)\dsp\rescaler_sse2.obj \
+    $(DIROBJ)\dsp\upsampling.obj \
+    $(DIROBJ)\dsp\upsampling_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\upsampling_msa.obj \
+    $(DIROBJ)\dsp\upsampling_neon.obj \
+    $(DIROBJ)\dsp\upsampling_sse2.obj \
+    $(DIROBJ)\dsp\upsampling_sse41.obj \
+    $(DIROBJ)\dsp\yuv.obj \
+    $(DIROBJ)\dsp\yuv_mips32.obj \
+    $(DIROBJ)\dsp\yuv_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\yuv_neon.obj \
+    $(DIROBJ)\dsp\yuv_sse2.obj \
+    $(DIROBJ)\dsp\yuv_sse41.obj \
+
+DSP_ENC_OBJS = \
+    $(DIROBJ)\dsp\cost.obj \
+    $(DIROBJ)\dsp\cost_mips32.obj \
+    $(DIROBJ)\dsp\cost_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\cost_neon.obj \
+    $(DIROBJ)\dsp\cost_sse2.obj \
+    $(DIROBJ)\dsp\enc.obj \
+    $(DIROBJ)\dsp\enc_mips32.obj \
+    $(DIROBJ)\dsp\enc_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\enc_msa.obj \
+    $(DIROBJ)\dsp\enc_neon.obj \
+    $(DIROBJ)\dsp\enc_sse2.obj \
+    $(DIROBJ)\dsp\enc_sse41.obj \
+    $(DIROBJ)\dsp\lossless_enc.obj \
+    $(DIROBJ)\dsp\lossless_enc_mips32.obj \
+    $(DIROBJ)\dsp\lossless_enc_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\lossless_enc_msa.obj \
+    $(DIROBJ)\dsp\lossless_enc_neon.obj \
+    $(DIROBJ)\dsp\lossless_enc_sse2.obj \
+    $(DIROBJ)\dsp\lossless_enc_sse41.obj \
+    $(DIROBJ)\dsp\ssim.obj \
+    $(DIROBJ)\dsp\ssim_sse2.obj \
+
+EX_ANIM_UTIL_OBJS = \
+    $(DIROBJ)\examples\anim_util.obj \
+
+IMAGEIO_DEC_OBJS = \
+    $(DIROBJ)\imageio\image_dec.obj \
+    $(DIROBJ)\imageio\jpegdec.obj \
+    $(DIROBJ)\imageio\metadata.obj \
+    $(DIROBJ)\imageio\pngdec.obj \
+    $(DIROBJ)\imageio\pnmdec.obj \
+    $(DIROBJ)\imageio\tiffdec.obj \
+    $(DIROBJ)\imageio\webpdec.obj \
+    $(DIROBJ)\imageio\wicdec.obj \
+
+IMAGEIO_ENC_OBJS = \
+    $(DIROBJ)\imageio\image_enc.obj \
+
+EX_GIF_DEC_OBJS = \
+    $(DIROBJ)\examples\gifdec.obj \
+
+EX_UTIL_OBJS = \
+    $(DIROBJ)\examples\example_util.obj \
+
+ENC_OBJS = \
+    $(DIROBJ)\enc\alpha_enc.obj \
+    $(DIROBJ)\enc\analysis_enc.obj \
+    $(DIROBJ)\enc\backward_references_cost_enc.obj \
+    $(DIROBJ)\enc\backward_references_enc.obj \
+    $(DIROBJ)\enc\config_enc.obj \
+    $(DIROBJ)\enc\cost_enc.obj \
+    $(DIROBJ)\enc\filter_enc.obj \
+    $(DIROBJ)\enc\frame_enc.obj \
+    $(DIROBJ)\enc\histogram_enc.obj \
+    $(DIROBJ)\enc\iterator_enc.obj \
+    $(DIROBJ)\enc\near_lossless_enc.obj \
+    $(DIROBJ)\enc\picture_enc.obj \
+    $(DIROBJ)\enc\picture_csp_enc.obj \
+    $(DIROBJ)\enc\picture_psnr_enc.obj \
+    $(DIROBJ)\enc\picture_rescale_enc.obj \
+    $(DIROBJ)\enc\picture_tools_enc.obj \
+    $(DIROBJ)\enc\predictor_enc.obj \
+    $(DIROBJ)\enc\quant_enc.obj \
+    $(DIROBJ)\enc\syntax_enc.obj \
+    $(DIROBJ)\enc\token_enc.obj \
+    $(DIROBJ)\enc\tree_enc.obj \
+    $(DIROBJ)\enc\vp8l_enc.obj \
+    $(DIROBJ)\enc\webp_enc.obj \
+
+EXTRAS_OBJS = \
+    $(DIROBJ)\extras\extras.obj \
+    $(DIROBJ)\extras\quality_estimate.obj \
+
+IMAGEIO_UTIL_OBJS = \
+    $(DIROBJ)\imageio\imageio_util.obj \
+
+MUX_OBJS = \
+    $(DIROBJ)\mux\anim_encode.obj \
+    $(DIROBJ)\mux\muxedit.obj \
+    $(DIROBJ)\mux\muxinternal.obj \
+    $(DIROBJ)\mux\muxread.obj \
+
+UTILS_DEC_OBJS = \
+    $(DIROBJ)\utils\bit_reader_utils.obj \
+    $(DIROBJ)\utils\color_cache_utils.obj \
+    $(DIROBJ)\utils\filters_utils.obj \
+    $(DIROBJ)\utils\huffman_utils.obj \
+    $(DIROBJ)\utils\palette.obj \
+    $(DIROBJ)\utils\quant_levels_dec_utils.obj \
+    $(DIROBJ)\utils\rescaler_utils.obj \
+    $(DIROBJ)\utils\random_utils.obj \
+    $(DIROBJ)\utils\thread_utils.obj \
+    $(DIROBJ)\utils\utils.obj \
+
+UTILS_ENC_OBJS = \
+    $(DIROBJ)\utils\bit_writer_utils.obj \
+    $(DIROBJ)\utils\huffman_encode_utils.obj \
+    $(DIROBJ)\utils\quant_levels_utils.obj \
+
+LIBWEBPDECODER_OBJS = $(DEC_OBJS) $(DSP_DEC_OBJS) $(UTILS_DEC_OBJS)
+LIBWEBP_OBJS = $(LIBWEBPDECODER_OBJS) $(ENC_OBJS) \
+               $(DSP_ENC_OBJS) $(UTILS_ENC_OBJS) $(DLL_OBJS)
+LIBWEBPMUX_OBJS = $(MUX_OBJS) $(LIBWEBPMUX_OBJS)
+LIBWEBPDEMUX_OBJS = $(DEMUX_OBJS) $(LIBWEBPDEMUX_OBJS)
+LIBSHARPYUV_OBJS = $(SHARPYUV_OBJS)
+
+OUT_LIBS = $(LIBWEBPDECODER) $(LIBWEBP) $(LIBSHARPYUV)
+!IF "$(ARCH)" == "ARM"
+ex: $(OUT_LIBS)
+all: ex
+!ELSE
+OUT_EXAMPLES = $(DIRBIN)\cwebp.exe $(DIRBIN)\dwebp.exe
+EXTRA_EXAMPLES = $(DIRBIN)\vwebp.exe $(DIRBIN)\webpmux.exe \
+                 $(DIRBIN)\img2webp.exe $(DIRBIN)\get_disto.exe \
+                 $(DIRBIN)\webp_quality.exe $(DIRBIN)\vwebp_sdl.exe \
+                 $(DIRBIN)\webpinfo.exe
+
+ex: $(OUT_LIBS) $(OUT_EXAMPLES)
+all: ex $(EXTRA_EXAMPLES)
+# NB: gif2webp.exe and anim_diff.exe are excluded from 'all' as libgif requires
+# C99 support which is only available from VS2013 onward.
+gif2webp: $(DIRBIN)\gif2webp.exe
+anim_diff: $(DIRBIN)\anim_diff.exe
+anim_dump: $(DIRBIN)\anim_dump.exe
+
+$(DIRBIN)\anim_diff.exe: $(DIROBJ)\examples\anim_diff.obj $(EX_ANIM_UTIL_OBJS)
+$(DIRBIN)\anim_diff.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\anim_diff.exe: $(EX_GIF_DEC_OBJS) $(LIBWEBPDEMUX) $(LIBWEBP)
+$(DIRBIN)\anim_dump.exe: $(DIROBJ)\examples\anim_dump.obj $(EX_ANIM_UTIL_OBJS)
+$(DIRBIN)\anim_dump.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\anim_dump.exe: $(EX_GIF_DEC_OBJS) $(LIBWEBPDEMUX) $(LIBWEBP)
+$(DIRBIN)\anim_dump.exe: $(IMAGEIO_ENC_OBJS)
+$(DIRBIN)\cwebp.exe: $(DIROBJ)\examples\cwebp.obj $(IMAGEIO_DEC_OBJS)
+$(DIRBIN)\cwebp.exe: $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\cwebp.exe: $(LIBWEBPDEMUX) $(LIBSHARPYUV)
+$(DIRBIN)\dwebp.exe: $(DIROBJ)\examples\dwebp.obj $(IMAGEIO_DEC_OBJS)
+$(DIRBIN)\dwebp.exe: $(IMAGEIO_ENC_OBJS)
+$(DIRBIN)\dwebp.exe: $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\dwebp.exe: $(LIBWEBPDEMUX)
+$(DIRBIN)\gif2webp.exe: $(DIROBJ)\examples\gif2webp.obj $(EX_GIF_DEC_OBJS)
+$(DIRBIN)\gif2webp.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS) $(LIBWEBPMUX)
+$(DIRBIN)\gif2webp.exe: $(LIBWEBP)
+$(DIRBIN)\vwebp.exe: $(DIROBJ)\examples\vwebp.obj $(EX_UTIL_OBJS)
+$(DIRBIN)\vwebp.exe: $(IMAGEIO_UTIL_OBJS) $(LIBWEBPDEMUX) $(LIBWEBP)
+$(DIRBIN)\vwebp_sdl.exe: $(DIROBJ)\extras\vwebp_sdl.obj
+$(DIRBIN)\vwebp_sdl.exe: $(DIROBJ)\extras\webp_to_sdl.obj
+$(DIRBIN)\vwebp_sdl.exe: $(IMAGEIO_UTIL_OBJS) $(LIBWEBP)
+$(DIRBIN)\webpmux.exe: $(DIROBJ)\examples\webpmux.obj $(LIBWEBPMUX)
+$(DIRBIN)\webpmux.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS) $(LIBWEBP)
+$(DIRBIN)\img2webp.exe: $(DIROBJ)\examples\img2webp.obj $(LIBWEBPMUX)
+$(DIRBIN)\img2webp.exe: $(IMAGEIO_DEC_OBJS)
+$(DIRBIN)\img2webp.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\img2webp.exe: $(LIBWEBPDEMUX) $(LIBWEBP) $(LIBSHARPYUV)
+$(DIRBIN)\get_disto.exe: $(DIROBJ)\extras\get_disto.obj
+$(DIRBIN)\get_disto.exe: $(IMAGEIO_DEC_OBJS) $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\get_disto.exe: $(LIBWEBPDEMUX) $(LIBWEBP)
+$(DIRBIN)\webp_quality.exe: $(DIROBJ)\extras\webp_quality.obj
+$(DIRBIN)\webp_quality.exe: $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\webp_quality.exe: $(EXTRAS_OBJS)
+# EXTRA_OBJS requires private symbols from dsp. Explicitly add those when
+# building libwebp as a dll.
+!IF "$(DLLBUILD)" == "TRUE"
+$(DIRBIN)\webp_quality.exe: $(DSP_DEC_OBJS)
+!ENDIF
+$(DIRBIN)\webp_quality.exe: $(LIBWEBP)
+$(DIRBIN)\webpinfo.exe: $(DIROBJ)\examples\webpinfo.obj
+$(DIRBIN)\webpinfo.exe: $(IMAGEIO_DEC_OBJS)
+$(DIRBIN)\webpinfo.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS)
+$(DIRBIN)\webpinfo.exe: $(LIBWEBPDEMUX) $(LIBWEBP)
+
+$(OUT_EXAMPLES): $(EX_UTIL_OBJS) $(LIBWEBP)
+$(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS): $(OUTPUT_DIRS)
+$(IMAGEIO_DEC_OBJS) $(IMAGEIO_ENC_OBJS) $(EXTRAS_OBJS): $(OUTPUT_DIRS)
+!ENDIF  # ARCH == ARM
+
+$(LIBSHARPYUV): $(LIBSHARPYUV_OBJS)
+$(LIBWEBPDECODER): $(LIBWEBPDECODER_OBJS)
+$(LIBWEBP): $(LIBWEBP_OBJS) $(LIBSHARPYUV)
+$(LIBWEBPMUX): $(LIBWEBPMUX_OBJS)
+$(LIBWEBPDEMUX): $(LIBWEBPDEMUX_OBJS)
+
+$(LIBWEBP_OBJS) $(LIBWEBPMUX_OBJS) $(LIBWEBPDEMUX_OBJS) $(LIBSHARPYUV_OBJS): \
+    $(OUTPUT_DIRS)
+
+!IF "$(DLLBUILD)" == "TRUE"
+{$(DIROBJ)}.c{$(DIROBJ)}.obj:
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$@  $<
+
+{src}.rc{$(DIROBJ)}.res:
+	$(RC) /fo$@ $<
+{src\demux}.rc{$(DIROBJ)\demux}.res:
+	$(RC) /fo$@ $<
+{src\mux}.rc{$(DIROBJ)\mux}.res:
+	$(RC) /fo$@ $<
+{sharpyuv}.rc{$(DIROBJ)\sharpyuv}.res:
+	$(RC) /fo$@ $<
+
+$(LIBSHARPYUV): $(DIROBJ)\sharpyuv\$(LIBSHARPYUV_BASENAME:_debug=).res
+$(LIBWEBP): $(LIBSHARPYUV) $(DIROBJ)\$(LIBWEBP_BASENAME:_debug=).res
+$(LIBWEBPDECODER): $(DIROBJ)\$(LIBWEBPDECODER_BASENAME:_debug=).res
+$(LIBWEBPMUX): $(LIBWEBP) $(DIROBJ)\mux\$(LIBWEBPMUX_BASENAME:_debug=).res
+$(LIBWEBPDEMUX): $(LIBWEBP) $(DIROBJ)\demux\$(LIBWEBPDEMUX_BASENAME:_debug=).res
+
+$(LIBWEBPDECODER) $(LIBWEBP) $(LIBWEBPMUX) $(LIBWEBPDEMUX) $(LIBSHARPYUV):
+	$(LNKDLL) /out:$(DIRBIN)\$(@B:_dll=.dll) /implib:$@ $(LFLAGS) $**
+	-xcopy $(DIROBJ)\*.pdb $(DIRLIB) /y
+!ELSE
+$(LIBWEBPDECODER) $(LIBWEBP) $(LIBWEBPMUX) $(LIBWEBPDEMUX) $(LIBSHARPYUV):
+	$(LNKLIB) /out:$@ $**
+	-xcopy $(DIROBJ)\*.pdb $(DIRLIB) /y
+!ENDIF
+
+$(OUTPUT_DIRS):
+	@if not exist "$(@)" mkdir "$(@)"
+
+.SUFFIXES: .c .obj .res .exe
+# File-specific flag builds. Note batch rules take precedence over wildcards,
+# so for now name each file individually.
+$(DIROBJ)\examples\anim_diff.obj: examples\anim_diff.c
+	$(CC) $(CFLAGS) /DWEBP_HAVE_GIF /Fd$(LIBWEBP_PDBNAME) \
+	  /Fo$(DIROBJ)\examples\ examples\$(@B).c
+$(DIROBJ)\examples\anim_dump.obj: examples\anim_dump.c
+	$(CC) $(CFLAGS) /DWEBP_HAVE_GIF /Fd$(LIBWEBP_PDBNAME) \
+	  /Fo$(DIROBJ)\examples\ examples\$(@B).c
+$(DIROBJ)\examples\anim_util.obj: examples\anim_util.c
+	$(CC) $(CFLAGS) /DWEBP_HAVE_GIF /Fd$(LIBWEBP_PDBNAME) \
+	  /Fo$(DIROBJ)\examples\ examples\$(@B).c
+$(DIROBJ)\examples\gif2webp.obj: examples\gif2webp.c
+	$(CC) $(CFLAGS) /DWEBP_HAVE_GIF /Fd$(LIBWEBP_PDBNAME) \
+	  /Fo$(DIROBJ)\examples\ examples\$(@B).c
+$(DIROBJ)\examples\gifdec.obj: examples\gifdec.c
+	$(CC) $(CFLAGS) /DWEBP_HAVE_GIF /Fd$(LIBWEBP_PDBNAME) \
+	  /Fo$(DIROBJ)\examples\ examples\$(@B).c
+# Batch rules
+{examples}.c{$(DIROBJ)\examples}.obj::
+	$(CC) $(CFLAGS) /Fd$(DIROBJ)\examples\ /Fo$(DIROBJ)\examples\ $<
+{extras}.c{$(DIROBJ)\extras}.obj::
+	$(CC) $(CFLAGS) /Fd$(DIROBJ)\extras\ /Fo$(DIROBJ)\extras\ $<
+{imageio}.c{$(DIROBJ)\imageio}.obj::
+	$(CC) $(CFLAGS) /Fd$(DIROBJ)\imageio\ /Fo$(DIROBJ)\imageio\ $<
+{sharpyuv}.c{$(DIROBJ)\sharpyuv}.obj::
+	$(CC) $(CFLAGS) /Fd$(DIROBJ)\sharpyuv\ /Fo$(DIROBJ)\sharpyuv\ $<
+{src\dec}.c{$(DIROBJ)\dec}.obj::
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\dec\ $<
+{src\demux}.c{$(DIROBJ)\demux}.obj::
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\demux\ $<
+{src\dsp}.c{$(DIROBJ)\dsp}.obj::
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\dsp\ $<
+{src\enc}.c{$(DIROBJ)\enc}.obj::
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\enc\ $<
+{src\mux}.c{$(DIROBJ)\mux}.obj::
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\mux\ $<
+{src\utils}.c{$(DIROBJ)\utils}.obj::
+	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\utils\ $<
+
+LNKLIBS     = ole32.lib windowscodecs.lib shlwapi.lib
+!IF "$(UNICODE)" == "1"
+LNKLIBS     = $(LNKLIBS) Shell32.lib
+!ENDIF
+
+{$(DIROBJ)\examples}.obj{$(DIRBIN)}.exe:
+	$(LNKEXE) $(LDFLAGS) /OUT:$@ $** $(LNKLIBS)
+
+{$(DIROBJ)\extras}.obj{$(DIRBIN)}.exe:
+	$(LNKEXE) $(LDFLAGS) /OUT:$@ $** $(LNKLIBS)
+
+clean::
+	@-erase /s $(DIROBJ)\*.dll 2> NUL
+	@-erase /s $(DIROBJ)\*.exp 2> NUL
+	@-erase /s $(DIROBJ)\*.idb 2> NUL
+	@-erase /s $(DIROBJ)\*.lib 2> NUL
+	@-erase /s $(DIROBJ)\*.obj 2> NUL
+	@-erase /s $(DIROBJ)\*.pch 2> NUL
+	@-erase /s $(DIROBJ)\*.pdb 2> NUL
+	@-erase /s $(DIROBJ)\*.res 2> NUL
+
+!ENDIF  # End of case where a config was provided.
--- a/external/libwebp/libwebp/NEWS
+++ b/external/libwebp/libwebp/NEWS
@@ -0,0 +1,311 @@
+- 6/23/2023: version 1.3.1
+  This is a binary compatible release.
+  * security fixes for lossless encoder (#603, chromium: #1420107, #1455619,
+    CVE-2023-1999)
+  * improve error reporting through WebPPicture error codes
+  * fix upsampling for RGB565 and RGBA4444 in NEON builds
+  * img2webp: add -sharp_yuv & -near_lossless
+  * Windows builds:
+    - fix compatibility with clang-cl (#607)
+    - improve Arm64 performance with cl.exe
+    - add Arm64EC support
+  * fix webp_js with emcc >= 3.1.27 (stack size change, #614)
+  * CMake fixes (#592, #610, #612)
+  * further updates to the container and lossless bitstream docs (#581, #611)
+
+- 12/16/2022: version 1.3.0
+  This is a binary compatible release.
+  * add libsharpyuv, which exposes -sharp_yuv/config.use_sharp_yuv
+    functionality to other libraries; libwebp now depends on this library
+  * major updates to the container and lossless bitstream docs (#448, #546,
+    #551)
+  * miscellaneous warning, bug & build fixes (#576, #583, #584)
+
+- 8/4/2022: version 1.2.4
+  This is a binary compatible release.
+  * restore CMake libwebpmux target name for compatibility with 1.2.2 (#575)
+  * fix lossless crunch mode encoding with WEBP_REDUCE_SIZE
+    (chromium: #1345547, #1345595, #1345772, #1345804)
+
+- 6/30/2022: version 1.2.3
+  This is a binary compatible release.
+  * security fix for lossless encoder (#565, chromium:1313709)
+  * improved progress granularity in WebPReportProgress() when using lossless
+  * improved precision in Sharp YUV (-sharp_yuv) conversion
+  * many corrections to webp-lossless-bitstream-spec.txt (#551)
+  * crash/leak fixes on error/OOM and other bug fixes (#558, #563, #569, #573)
+
+- 1/11/2022: version 1.2.2
+  This is a binary compatible release.
+  * webpmux: add "-set bgcolor A,R,G,B"
+  * add ARM64 NEON support for MSVC builds (#539)
+  * fix duplicate include error in Xcode when using multiple XCFrameworks in a
+    project (#542)
+  * doc updates and bug fixes (#538, #544, #548, #550)
+
+- 7/20/2021: version 1.2.1
+  This is a binary compatible release.
+  * minor lossless encoder improvements and x86 color conversion speed up
+  * add ARM64 simulator support to xcframeworkbuild.sh (#510)
+  * further security related hardening in libwebp & examples
+    (issues: #497, #508, #518)
+    (chromium: #1196480, #1196773, #1196775, #1196777, #1196778, #1196850)
+    (oss-fuzz: #28658, #28978)
+  * toolchain updates and bug fixes (#498, #501, #502, #504, #505, #506, #509,
+                                     #533)
+  * use more inclusive language within the source (#507)
+
+- 12/23/2020: version 1.2.0
+  * API changes:
+    - libwebp:
+      encode.h: add a qmin / qmax range for quality factor (cwebp adds -qrange)
+  * lossless encoder improvements
+  * SIMD support for Wasm builds
+  * add xcframeworkbuild.sh, supports Mac Catalyst builds
+  * import fuzzers from oss-fuzz & chromium (#409)
+  * webpmux: add an '-set loop <value>' option (#494)
+  * toolchain updates and bug fixes (#449, #463, #470, #475, #477, #478, #479,
+    #488, #491)
+
+- 12/18/2019: version 1.1.0
+  * API changes:
+    - libwebp:
+      WebPMalloc (issue #442)
+    - extras:
+      WebPUnmultiplyARGB
+  * alpha decode fix (issue #439)
+  * toolchain updates and bug fixes
+    (chromium: #1026858, #1027136, #1027409, #1028620, #1028716, #995200)
+    (oss-fuzz: #19430, #19447)
+
+- 7/4/2019: version 1.0.3
+  This is a binary compatible release.
+  * resize fixes for Nx1 sizes and the addition of non-opaque alpha values for
+    odd sizes (issues #418, #434)
+  * lossless encode/decode performance improvements
+  * lossy compression performance improvement at low quality levels with flat
+    content (issue #432)
+  * python swig files updated to support python 3
+  Tool updates:
+    vwebp will now preserve the aspect ratio of images that exceed monitor
+    resolution by scaling the image to fit (issue #433)
+
+- 1/14/2019: version 1.0.2
+  This is a binary compatible release.
+  * (Windows) unicode file support in the tools (linux and mac already had
+    support, issue #398)
+  * lossless encoder speedups
+  * lossy encoder speedup on ARM
+  * lossless multi-threaded security fix (chromium:917029)
+
+- 11/2/2018: version 1.0.1
+  This is a binary compatible release.
+  * lossless encoder speedups
+  * big-endian fix for alpha decoding (issue #393)
+  * gif2webp fix for loop count=65535 transcode (issue #382)
+  * further security related hardening in libwebp & libwebpmux
+    (issues #383, #385, #386, #387, #388, #391)
+    (oss-fuzz #9099, #9100, #9105, #9106, #9111, #9112, #9119, #9123, #9170,
+              #9178, #9179, #9183, #9186, #9191, #9364, #9417, #9496, #10349,
+              #10423, #10634, #10700, #10838, #10922, #11021, #11088, #11152)
+  * miscellaneous bug & build fixes (issues #381, #394, #396, #397, #400)
+
+- 4/2/2018: version 1.0.0
+  This is a binary compatible release.
+  * lossy encoder improvements to avoid chroma shifts in various circumstances
+    (issues #308, #340)
+  * big-endian fixes for decode, RGBA import and WebPPictureDistortion
+  Tool updates:
+    gifwebp, anim_diff - default duration behavior (<= 10ms) changed to match
+                         web browsers, transcoding tools (issue #379)
+    img2webp, webpmux - allow options to be passed in via a file (issue #355)
+
+- 11/24/2017: version 0.6.1
+  This is a binary compatible release.
+  * lossless performance and compression improvements + a new 'cruncher' mode
+    (-m 6 -q 100)
+  * ARM performance improvements with clang (15-20% w/ndk r15c, issue #339)
+  * webp-js: emscripten/webassembly based javascript decoder
+  * miscellaneous bug & build fixes (issue #329, #332, #343, #353, #360, #361,
+    #363)
+  Tool updates / additions:
+    added webpinfo - prints file format information (issue #330)
+    gif2webp - loop behavior modified to match Chrome M63+ (crbug.com/649264);
+               '-loop_compatibility' can be used for the old behavior
+
+- 1/26/2017: version 0.6.0
+  * lossless performance and compression improvements
+  * miscellaneous performance improvements (SSE2, NEON, MSA)
+  * webpmux gained a -duration option allowing for frame timing modification
+  * new img2webp utility allowing a sequence of images to be converted to
+    animated webp
+  * API changes:
+    - libwebp:
+      WebPPictureSharpARGBToYUVA
+      WebPPlaneDistortion
+    - libwebpmux / gif2webp:
+      WebPAnimEncoderOptions: kmax <= 0 now disables keyframes, kmax == 1
+                              forces all keyframes. See mux.h and the gif2webp
+                              manpage for details.
+
+- 12/13/2016: version 0.5.2
+  This is a binary compatible release.
+  This release covers CVE-2016-8888 and CVE-2016-9085.
+  * further security related hardening in the tools; fixes to
+    gif2webp/AnimEncoder (issues #310, #314, #316, #322), cwebp/libwebp (issue
+    #312)
+  * full libwebp (encoder & decoder) iOS framework; libwebpdecoder
+    WebP.framework renamed to WebPDecoder.framework (issue #307)
+  * CMake support for Android Studio (2.2)
+  * miscellaneous build related fixes (issue #306, #313)
+  * miscellaneous documentation improvements (issue #225)
+  * minor lossy encoder fixes and improvements
+
+- 6/14/2016: version 0.5.1
+  This is a binary compatible release.
+  * miscellaneous bug fixes (issues #280, #289)
+  * reverted alpha plane encoding with color cache for compatibility with
+    libwebp 0.4.0->0.4.3 (issues #291, #298)
+  * lossless encoding performance improvements
+  * memory reduction in both lossless encoding and decoding
+  * force mux output to be in the extended format (VP8X) when undefined chunks
+    are present (issue #294)
+  * gradle, cmake build support
+  * workaround for compiler bug causing 64-bit decode failures on android
+    devices using clang-3.8 in the r11c NDK
+  * various WebPAnimEncoder improvements
+
+- 12/17/2015: version 0.5.0
+  * miscellaneous bug & build fixes (issues #234, #258, #274, #275, #278)
+  * encoder & decoder speed-ups on x86/ARM/MIPS for lossy & lossless
+    - note! YUV->RGB conversion was sped-up, but the results will be slightly
+      different from previous releases
+  * various lossless encoder improvements
+  * gif2webp improvements, -min_size option added
+  * tools fully support input from stdin and output to stdout (issue #168)
+  * New WebPAnimEncoder API for creating animations
+  * New WebPAnimDecoder API for decoding animations
+  * other API changes:
+    - libwebp:
+      WebPPictureSmartARGBToYUVA() (-pre 4 in cwebp)
+      WebPConfig::exact (-exact in cwebp; -alpha_cleanup is now the default)
+      WebPConfig::near_lossless (-near_lossless in cwebp)
+      WebPFree() (free'ing webp allocated memory in other languages)
+      WebPConfigLosslessPreset()
+      WebPMemoryWriterClear()
+    - libwebpdemux: removed experimental fragment related fields and functions
+    - libwebpmux: WebPMuxSetCanvasSize()
+  * new libwebpextras library with some uncommon import functions:
+    WebPImportGray/WebPImportRGB565/WebPImportRGB4444
+
+- 10/15/15: version 0.4.4
+  This is a binary compatible release.
+  * rescaling out-of-bounds read fix (issue #254)
+  * various build fixes and improvements (issues #253, #259, #262, #267, #268)
+  * container documentation update
+  * gif2webp transparency fix (issue #245)
+
+- 3/3/15: version 0.4.3
+  This is a binary compatible release.
+  * Android / gcc / iOS / MSVS build fixes and improvements
+  * lossless decode fix (issue #239 -- since 0.4.0)
+  * documentation / vwebp updates for animation
+  * multi-threading fix (issue #234)
+
+- 10/13/14: version 0.4.2
+  This is a binary compatible release.
+  * Android / gcc build fixes
+  * (Windows) fix reading from stdin and writing to stdout
+  * gif2webp: miscellaneous fixes
+  * fix 'alpha-leak' with lossy compression (issue #220)
+  * the lossless bitstream spec has been amended to reflect the current code
+
+- 7/24/14: version 0.4.1
+  This is a binary compatible release.
+  * AArch64 (arm64) & MIPS support/optimizations
+  * NEON assembly additions:
+    - ~25% faster lossy decode / encode (-m 4)
+    - ~10% faster lossless decode
+    - ~5-10% faster lossless encode (-m 3/4)
+  * dwebp/vwebp can read from stdin
+  * cwebp/gif2webp can write to stdout
+  * cwebp can read webp files; useful if storing sources as webp lossless
+
+- 12/19/13: version 0.4.0
+  * improved gif2webp tool
+  * numerous fixes, compression improvement and speed-up
+  * dither option added to decoder (dwebp -dither 50 ...)
+  * improved multi-threaded modes (-mt option)
+  * improved filtering strength determination
+  * New function: WebPMuxGetCanvasSize
+  * BMP and TIFF format output added to 'dwebp'
+  * Significant memory reduction for decoding lossy images with alpha.
+  * Intertwined decoding of RGB and alpha for a shorter
+    time-to-first-decoded-pixel.
+  * WebPIterator has a new member 'has_alpha' denoting whether the frame
+    contains transparency.
+  * Container spec amended with new 'blending method' for animation.
+
+- 6/13/13: version 0.3.1
+  This is a binary compatible release.
+  * Add incremental decoding support for images containing ALPH and ICCP chunks.
+  * Python bindings via swig for the simple encode/decode interfaces similar to
+    Java.
+
+- 3/20/13: version 0.3.0
+  This is a binary compatible release.
+  * WebPINewRGB/WebPINewYUVA accept being passed a NULL output buffer
+    and will perform auto-allocation.
+  * default filter option is now '-strong -f 60'
+  * encoding speed-up for lossy methods 3 to 6
+  * alpha encoding can be done in parallel to lossy using 'cwebp -mt ...'
+  * color profile, metadata (XMP/EXIF) and animation support finalized in the
+    container.
+  * various NEON assembly additions
+  Tool updates / additions:
+    * gif2webp added
+    * vwebp given color profile & animation support
+    * cwebp can preserve color profile / metadata with '-metadata'
+
+- 10/30/12: version 0.2.1
+  * Various security related fixes
+  * cwebp.exe: fix import errors on Windows XP
+  * enable DLL builds for mingw targets
+
+- 8/3/12: version 0.2.0
+  * Add support for ARGB -> YUVA conversion for lossless decoder
+    New functions: WebPINewYUVA, WebPIDecGetYUVA
+  * Add stats for lossless and alpha encoding
+  * Security related hardening: allocation and size checks
+  * Add PAM output support to dwebp
+
+- 7/19/12: version 0.1.99
+  * This is a pre-release of 0.2.0, not an rc to allow for further
+    incompatible changes based on user feedback.
+  * Alpha channel encode/decode support.
+  * Lossless encoder/decoder.
+  * Add TIFF input support to cwebp.
+  Incompatible changes:
+    * The encode ABI has been modified to support alpha encoding.
+    * Deprecated function WebPINew() has been removed.
+    * Decode function signatures have changed to consistently use size_t over
+      int/uint32_t.
+    * decode_vp8.h is no longer installed system-wide.
+    * cwebp will encode the alpha channel if present.
+
+- 9/19/11: version 0.1.3
+  * Advanced decoding APIs.
+  * On-the-fly cropping and rescaling of images.
+  * SSE2 instructions for decoding performance optimizations on x86 based
+    platforms.
+  * Support Multi-threaded decoding.
+  * 40% improvement in Decoding performance.
+  * Add support for RGB565, RGBA4444 & ARGB image colorspace.
+  * Better handling of large picture encoding.
+
+- 3/25/11: version 0.1.2
+  * Incremental decoding: picture can be decoded byte-by-byte if needs be.
+  * lot of bug-fixes, consolidation and stabilization
+
+- 2/23/11: initial release of version 0.1, with the new encoder
+- 9/30/10: initial release version with only the lightweight decoder
--- a/external/libwebp/libwebp/PATENTS
+++ b/external/libwebp/libwebp/PATENTS
@@ -0,0 +1,23 @@
+Additional IP Rights Grant (Patents)
+------------------------------------
+
+"These implementations" means the copyrightable works that implement the WebM
+codecs distributed by Google as part of the WebM Project.
+
+Google hereby grants to you a perpetual, worldwide, non-exclusive, no-charge,
+royalty-free, irrevocable (except as stated in this section) patent license to
+make, have made, use, offer to sell, sell, import, transfer, and otherwise
+run, modify and propagate the contents of these implementations of WebM, where
+such license applies only to those patent claims, both currently owned by
+Google and acquired in the future, licensable by Google that are necessarily
+infringed by these implementations of WebM. This grant does not include claims
+that would be infringed only as a consequence of further modification of these
+implementations. If you or your agent or exclusive licensee institute or order
+or agree to the institution of patent litigation or any other patent
+enforcement activity against any entity (including a cross-claim or
+counterclaim in a lawsuit) alleging that any of these implementations of WebM
+or any code incorporated within any of these implementations of WebM
+constitute direct or contributory patent infringement, or inducement of
+patent infringement, then any patent rights granted to you under this License
+for these implementations of WebM shall terminate as of the date such
+litigation is filed.
--- a/external/libwebp/libwebp/PRESUBMIT.py
+++ b/external/libwebp/libwebp/PRESUBMIT.py
@@ -0,0 +1,245 @@
+# Copyright (c) 2021, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#
+#   * Neither the name of Google nor the names of its contributors may
+#     be used to endorse or promote products derived from this software
+#     without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+"""Top-level presubmit script for libwebp.
+
+See https://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
+details on the presubmit API built into depot_tools.
+"""
+
+import re
+import subprocess2
+
+USE_PYTHON3 = True
+_BASH_INDENTATION = "2"
+_GIT_COMMIT_SUBJECT_LENGTH = 65
+_INCLUDE_BASH_FILES_ONLY = [r".*\.sh$"]
+_INCLUDE_MAN_FILES_ONLY = [r"man/.+\.1$"]
+_INCLUDE_SOURCE_FILES_ONLY = [r".*\.[ch]$"]
+_LIBWEBP_MAX_LINE_LENGTH = 80
+
+
+def _CheckCommitSubjectLength(input_api, output_api):
+  """Ensures commit's subject length is no longer than 65 chars."""
+  name = "git-commit subject"
+  cmd = ["git", "log", "-1", "--pretty=%s"]
+  start = input_api.time.time()
+  proc = subprocess2.Popen(
+      cmd,
+      stderr=subprocess2.PIPE,
+      stdout=subprocess2.PIPE,
+      universal_newlines=True)
+
+  stdout, _ = proc.communicate()
+  duration = input_api.time.time() - start
+
+  if not re.match(r"^Revert",
+                  stdout) and (len(stdout) - 1) > _GIT_COMMIT_SUBJECT_LENGTH:
+    failure_msg = (
+        "The commit subject: %s is too long (%d chars)\n"
+        "Try to keep this to 50 or less (up to 65 is permitted for "
+        "non-reverts).\n"
+        "https://www.git-scm.com/book/en/v2/Distributed-Git-Contributing-to-a-"
+        "Project#_commit_guidelines") % (stdout, len(stdout) - 1)
+    return output_api.PresubmitError("%s\n (%4.2fs) failed\n%s" %
+                                     (name, duration, failure_msg))
+
+  return output_api.PresubmitResult("%s\n (%4.2fs) success" % (name, duration))
+
+
+def _CheckDuplicateFiles(input_api, output_api):
+  """Ensures there are not repeated filenames."""
+  all_files = []
+  for f in input_api.change.AllFiles():
+    for include_file in _INCLUDE_SOURCE_FILES_ONLY:
+      if re.match(include_file, f):
+        all_files.append(f)
+        break
+
+  basename_to_path = {}
+  for f in all_files:
+    basename_file = input_api.basename(f)
+    if basename_file in basename_to_path:
+      basename_to_path[basename_file].append(f)
+    else:
+      basename_to_path[basename_file] = [f]
+
+  dupes = []
+  for files in basename_to_path.values():
+    if len(files) > 1:
+      dupes.extend(files)
+
+  if dupes:
+    return output_api.PresubmitError(
+        "Duplicate source files, rebase or rename some to make them unique:\n%s"
+        % dupes)
+  return output_api.PresubmitResult("No duplicates, success\n")
+
+
+def _GetFilesToSkip(input_api):
+  return list(input_api.DEFAULT_FILES_TO_SKIP) + [
+      r"swig/.*\.py$",
+      r"\.pylintrc$",
+  ]
+
+
+def _RunManCmd(input_api, output_api, man_file):
+  """man command wrapper."""
+  cmd = ["man", "--warnings", "-EUTF-8", "-l", "-Tutf8", "-Z", man_file]
+  name = "Check %s file." % man_file
+  start = input_api.time.time()
+  output, _ = subprocess2.communicate(
+      cmd, stdout=None, stderr=subprocess2.PIPE, universal_newlines=True)
+  duration = input_api.time.time() - start
+  if output[1]:
+    return output_api.PresubmitError("%s\n%s (%4.2fs) failed\n%s" %
+                                     (name, " ".join(cmd), duration, output[1]))
+  return output_api.PresubmitResult("%s\n%s (%4.2fs)\n" %
+                                    (name, " ".join(cmd), duration))
+
+
+def _RunShellCheckCmd(input_api, output_api, bash_file):
+  """shellcheck command wrapper."""
+  cmd = ["shellcheck", "-x", "-oall", "-sbash", bash_file]
+  name = "Check %s file." % bash_file
+  start = input_api.time.time()
+  output, rc = subprocess2.communicate(
+      cmd, stdout=None, stderr=subprocess2.PIPE, universal_newlines=True)
+  duration = input_api.time.time() - start
+  if rc == 0:
+    return output_api.PresubmitResult("%s\n%s (%4.2fs)\n" %
+                                      (name, " ".join(cmd), duration))
+  return output_api.PresubmitError("%s\n%s (%4.2fs) failed\n%s" %
+                                   (name, " ".join(cmd), duration, output[1]))
+
+
+def _RunShfmtCheckCmd(input_api, output_api, bash_file):
+  """shfmt command wrapper."""
+  cmd = [
+      "shfmt", "-i", _BASH_INDENTATION, "-bn", "-ci", "-sr", "-kp", "-d",
+      bash_file
+  ]
+  name = "Check %s file." % bash_file
+  start = input_api.time.time()
+  output, rc = subprocess2.communicate(
+      cmd, stdout=None, stderr=subprocess2.PIPE, universal_newlines=True)
+  duration = input_api.time.time() - start
+  if rc == 0:
+    return output_api.PresubmitResult("%s\n%s (%4.2fs)\n" %
+                                      (name, " ".join(cmd), duration))
+  return output_api.PresubmitError("%s\n%s (%4.2fs) failed\n%s" %
+                                   (name, " ".join(cmd), duration, output[1]))
+
+
+def _RunCmdOnCheckedFiles(input_api, output_api, run_cmd, files_to_check):
+  """Ensure that libwebp/ files are clean."""
+  file_filter = lambda x: input_api.FilterSourceFile(
+      x, files_to_check=files_to_check, files_to_skip=None)
+
+  affected_files = input_api.change.AffectedFiles(file_filter=file_filter)
+  results = [
+      run_cmd(input_api, output_api, f.AbsoluteLocalPath())
+      for f in affected_files
+  ]
+  return results
+
+
+def _CommonChecks(input_api, output_api):
+  """Ensures this patch does not have trailing spaces, extra EOLs,
+     or long lines.
+  """
+  results = []
+  results.extend(
+      input_api.canned_checks.CheckChangeHasNoCrAndHasOnlyOneEol(
+          input_api, output_api))
+  results.extend(
+      input_api.canned_checks.CheckChangeHasNoTabs(input_api, output_api))
+  results.extend(
+      input_api.canned_checks.CheckChangeHasNoStrayWhitespace(
+          input_api, output_api))
+  results.append(_CheckCommitSubjectLength(input_api, output_api))
+  results.append(_CheckDuplicateFiles(input_api, output_api))
+
+  source_file_filter = lambda x: input_api.FilterSourceFile(
+      x, files_to_skip=_GetFilesToSkip(input_api))
+  results.extend(
+      input_api.canned_checks.CheckLongLines(
+          input_api,
+          output_api,
+          maxlen=_LIBWEBP_MAX_LINE_LENGTH,
+          source_file_filter=source_file_filter))
+
+  results.extend(
+      input_api.canned_checks.CheckPatchFormatted(
+          input_api,
+          output_api,
+          check_clang_format=False,
+          check_python=True,
+          result_factory=output_api.PresubmitError))
+  results.extend(
+      _RunCmdOnCheckedFiles(input_api, output_api, _RunManCmd,
+                            _INCLUDE_MAN_FILES_ONLY))
+  # Run pylint.
+  results.extend(
+      input_api.canned_checks.RunPylint(
+          input_api,
+          output_api,
+          files_to_skip=_GetFilesToSkip(input_api),
+          pylintrc=".pylintrc",
+          version="2.7"))
+
+  # Binaries shellcheck and shfmt are not installed in depot_tools.
+  # Installation is needed
+  try:
+    subprocess2.communicate(["shellcheck", "--version"])
+    results.extend(
+        _RunCmdOnCheckedFiles(input_api, output_api, _RunShellCheckCmd,
+                              _INCLUDE_BASH_FILES_ONLY))
+    print("shfmt")
+    subprocess2.communicate(["shfmt", "-version"])
+    results.extend(
+        _RunCmdOnCheckedFiles(input_api, output_api, _RunShfmtCheckCmd,
+                              _INCLUDE_BASH_FILES_ONLY))
+  except OSError as os_error:
+    results.append(
+        output_api.PresubmitPromptWarning(
+            "%s\nPlease install missing binaries locally." % os_error.args[0]))
+  return results
+
+
+def CheckChangeOnUpload(input_api, output_api):
+  results = []
+  results.extend(_CommonChecks(input_api, output_api))
+  return results
+
+
+def CheckChangeOnCommit(input_api, output_api):
+  results = []
+  results.extend(_CommonChecks(input_api, output_api))
+  return results
--- a/external/libwebp/libwebp/README.md
+++ b/external/libwebp/libwebp/README.md
@@ -0,0 +1,53 @@
+# WebP Codec
+
+```
+      __   __  ____  ____  ____
+     /  \\/  \/  _ \/  _ )/  _ \
+     \       /   __/  _  \   __/
+      \__\__/\____/\_____/__/ ____  ___
+            / _/ /    \    \ /  _ \/ _/
+           /  \_/   / /   \ \   __/  \__
+           \____/____/\_____/_____/____/v1.3.1
+```
+
+WebP codec is a library to encode and decode images in WebP format. This package
+contains the library that can be used in other programs to add WebP support, as
+well as the command line tools 'cwebp' and 'dwebp' to compress and decompress
+images respectively.
+
+See https://developers.google.com/speed/webp for details on the image format.
+
+The latest source tree is available at
+https://chromium.googlesource.com/webm/libwebp
+
+It is released under the same license as the WebM project. See
+https://www.webmproject.org/license/software/ or the "COPYING" file for details.
+An additional intellectual property rights grant can be found in the file
+PATENTS.
+
+## Building
+
+See the [building documentation](doc/building.md).
+
+## Encoding and Decoding Tools
+
+The examples/ directory contains tools to encode and decode images and
+animations, view information about WebP images, and more. See the
+[tools documentation](doc/tools.md).
+
+## APIs
+
+See the [APIs documentation](doc/api.md), and API usage examples in the
+`examples/` directory.
+
+## Bugs
+
+Please report all bugs to the issue tracker: https://bugs.chromium.org/p/webp
+
+Patches welcome! See [how to contribute](CONTRIBUTING.md).
+
+## Discuss
+
+Email: webp-discuss@webmproject.org
+
+Web: https://groups.google.com/a/webmproject.org/group/webp-discuss
--- a/external/libwebp/libwebp/autogen.sh
+++ b/external/libwebp/libwebp/autogen.sh
@@ -0,0 +1,2 @@
+#! /bin/sh -e
+exec autoreconf -fi
--- a/external/libwebp/libwebp/build.gradle
+++ b/external/libwebp/libwebp/build.gradle
@@ -0,0 +1,444 @@
+// Define dependencies.
+buildscript {
+  repositories {
+    maven {
+      url "https://jcenter.bintray.com"
+    }
+  }
+  dependencies {
+    classpath "com.android.tools.build:gradle:${ANDROID_GRADLE_PLUGIN_VERSION}"
+  }
+}
+
+// Define versions in the project.
+project.ext {
+  buildToolsVersion = "${BUILD_TOOLS_VERSION}"
+  compileSdkVersion = COMPILE_SDK_VERSION.toInteger()
+}
+
+// Core libraries and executables.
+apply plugin: "c"
+def NEON
+model {
+  buildTypes {
+    debug
+    release
+  }
+  platforms {
+    arm {
+      architecture "arm"
+    }
+    arm64 {
+      architecture "arm64"
+    }
+    x86 {
+      architecture "x86"
+    }
+    x64 {
+      architecture "x86_64"
+    }
+    mips32r2
+    mips32r5
+    mips64r6
+  }
+  toolChains {
+    gcc(Gcc) {
+      target("mips32r2") {
+        cCompiler.args "-mips32r2"
+      }
+      target("mips32r5") {
+        cCompiler.args "-mips32r5"
+      }
+      target("mips64r6") {
+        cCompiler.args "-mips64r6"
+      }
+    }
+  }
+  binaries {
+    all {
+      if (toolChain in Gcc) {
+        cCompiler.args "-fPIC"
+        cCompiler.args "-Wall"
+        cCompiler.define "ANDROID"
+        cCompiler.define "HAVE_MALLOC_H"
+      }
+      // Optimizations.
+      if (buildType == buildTypes.release) {
+        if (toolChain in Gcc) {
+          cCompiler.args "-finline-functions"
+          cCompiler.args "-ffast-math"
+          cCompiler.args "-ffunction-sections"
+          cCompiler.args "-fdata-sections"
+        }
+        if (toolChain in Clang) {
+          cCompiler.args "-frename-registers -s"
+        }
+      }
+      // mips32 fails to build with clang from r14b
+      // https://bugs.chromium.org/p/webp/issues/detail?id=343
+      if (toolChain in Clang) {
+        if (getTargetPlatform() == "mips") {
+          cCompiler.args "-no-integrated-as"
+        }
+      }
+      // Check for NEON usage.
+      if (getTargetPlatform() == "arm") {
+        NEON = "c.neon"
+        cCompiler.define "HAVE_CPU_FEATURES_H"
+      } else {
+        NEON = "c"
+      }
+
+      cCompiler.args "-I" + file(".").absolutePath
+    }
+    // Link to pthread for shared libraries.
+    withType(SharedLibraryBinarySpec) {
+      if (toolChain in Gcc) {
+        cCompiler.define "HAVE_PTHREAD"
+        cCompiler.define "WEBP_USE_THREAD"
+        linker.args "-pthread"
+      }
+    }
+  }
+  components {
+    webp(NativeLibrarySpec) {
+      sources {
+        c {
+          source {
+            srcDir "sharpyuv"
+            include "sharpyuv.c"
+            include "sharpyuv_cpu.c"
+            include "sharpyuv_csp.c"
+            include "sharpyuv_dsp.c"
+            include "sharpyuv_gamma.c"
+            include "sharpyuv_neon.c"
+            include "sharpyuv_sse2.c"
+            srcDir "src/dec"
+            include "alpha_dec.c"
+            include "buffer_dec.c"
+            include "frame_dec.c"
+            include "idec_dec.c"
+            include "io_dec.c"
+            include "quant_dec.c"
+            include "tree_dec.c"
+            include "vp8_dec.c"
+            include "vp8l_dec.c"
+            include "webp_dec.c"
+            srcDir "src/dsp"
+            include "alpha_processing.c"
+            include "alpha_processing_mips_dsp_r2.c"
+            include "alpha_processing_neon.$NEON"
+            include "alpha_processing_sse2.c"
+            include "alpha_processing_sse41.c"
+            include "cpu.c"
+            include "dec.c"
+            include "dec_clip_tables.c"
+            include "dec_mips32.c"
+            include "dec_mips_dsp_r2.c"
+            include "dec_msa.c"
+            include "dec_neon.$NEON"
+            include "dec_sse2.c"
+            include "dec_sse41.c"
+            include "filters.c"
+            include "filters_mips_dsp_r2.c"
+            include "filters_msa.c"
+            include "filters_neon.$NEON"
+            include "filters_sse2.c"
+            include "lossless.c"
+            include "lossless_mips_dsp_r2.c"
+            include "lossless_msa.c"
+            include "lossless_neon.$NEON"
+            include "lossless_sse2.c"
+            include "lossless_sse41.c"
+            include "rescaler.c"
+            include "rescaler_mips32.c"
+            include "rescaler_mips_dsp_r2.c"
+            include "rescaler_msa.c"
+            include "rescaler_neon.$NEON"
+            include "rescaler_sse2.c"
+            include "upsampling.c"
+            include "upsampling_mips_dsp_r2.c"
+            include "upsampling_msa.c"
+            include "upsampling_neon.$NEON"
+            include "upsampling_sse2.c"
+            include "upsampling_sse41.c"
+            include "yuv.c"
+            include "yuv_mips32.c"
+            include "yuv_mips_dsp_r2.c"
+            include "yuv_neon.$NEON"
+            include "yuv_sse2.c"
+            include "yuv_sse41.c"
+            srcDir "src/utils"
+            include "bit_reader_utils.c"
+            include "color_cache_utils.c"
+            include "filters_utils.c"
+            include "huffman_utils.c"
+            include "palette.c"
+            include "quant_levels_dec_utils.c"
+            include "random_utils.c"
+            include "rescaler_utils.c"
+            include "thread_utils.c"
+            include "utils.c"
+            srcDir "src/dsp"
+            include "cost.c"
+            include "cost_mips32.c"
+            include "cost_mips_dsp_r2.c"
+            include "cost_neon.$NEON"
+            include "cost_sse2.c"
+            include "enc.c"
+            include "enc_mips32.c"
+            include "enc_mips_dsp_r2.c"
+            include "enc_msa.c"
+            include "enc_neon.$NEON"
+            include "enc_sse2.c"
+            include "enc_sse41.c"
+            include "lossless_enc.c"
+            include "lossless_enc_mips32.c"
+            include "lossless_enc_mips_dsp_r2.c"
+            include "lossless_enc_msa.c"
+            include "lossless_enc_neon.$NEON"
+            include "lossless_enc_sse2.c"
+            include "lossless_enc_sse41.c"
+            include "ssim.c"
+            include "ssim_sse2.c"
+            srcDir "src/enc"
+            include "alpha_enc.c"
+            include "analysis_enc.c"
+            include "backward_references_cost_enc.c"
+            include "backward_references_enc.c"
+            include "config_enc.c"
+            include "cost_enc.c"
+            include "filter_enc.c"
+            include "frame_enc.c"
+            include "histogram_enc.c"
+            include "iterator_enc.c"
+            include "near_lossless_enc.c"
+            include "picture_enc.c"
+            include "picture_csp_enc.c"
+            include "picture_psnr_enc.c"
+            include "picture_rescale_enc.c"
+            include "picture_tools_enc.c"
+            include "predictor_enc.c"
+            include "quant_enc.c"
+            include "syntax_enc.c"
+            include "token_enc.c"
+            include "tree_enc.c"
+            include "vp8l_enc.c"
+            include "webp_enc.c"
+            srcDir "src/utils"
+            include "bit_writer_utils.c"
+            include "huffman_encode_utils.c"
+            include "quant_levels_utils.c"
+          }
+          exportedHeaders {
+            srcDir "src"
+          }
+        }
+      }
+    }
+
+    webpdemux(NativeLibrarySpec) {
+      sources {
+        c {
+          source {
+            srcDir "src/demux"
+            include "anim_decode.c"
+            include "demux.c"
+          }
+        }
+      }
+    }
+
+    webpmux(NativeLibrarySpec) {
+      sources {
+        c {
+          source {
+            srcDir "src/mux/"
+            include "anim_encode.c"
+            include "muxedit.c"
+            include "muxinternal.c"
+            include "muxread.c"
+          }
+        }
+      }
+    }
+
+    // Executables from examples.
+    example_util(NativeLibrarySpec) {
+      binaries {
+        all {
+          lib library: "webp", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "example_util.c"
+          }
+        }
+      }
+    }
+
+    imageio_util(NativeLibrarySpec) {
+      binaries {
+        all {
+          lib library: "webp", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./imageio"
+            include "imageio_util.c"
+          }
+        }
+      }
+    }
+
+    imagedec(NativeLibrarySpec) {
+      binaries {
+        all {
+          lib library: "webpdemux", linkage: "static"
+          lib library: "webp", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./imageio"
+            include "image_dec.c"
+            include "jpegdec.c"
+            include "metadata.c"
+            include "pngdec.c"
+            include "pnmdec.c"
+            include "tiffdec.c"
+            include "webpdec.c"
+          }
+        }
+      }
+    }
+
+    imageenc(NativeLibrarySpec) {
+      binaries {
+        all {
+          lib library: "webp", linkage: "static"
+          lib library: "imageio_util", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./imageio"
+            include "image_enc.c"
+          }
+        }
+      }
+    }
+
+    cwebp(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "imagedec", linkage: "static"
+          lib library: "imageio_util", linkage: "static"
+          lib library: "webpdemux", linkage: "static"
+          lib library: "webp", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "cwebp.c"
+          }
+        }
+      }
+    }
+
+    dwebp(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "imagedec", linkage: "static"
+          lib library: "imageenc", linkage: "static"
+          lib library: "imageio_util", linkage: "static"
+          lib library: "webpdemux", linkage: "static"
+          lib library: "webp"
+        }
+      }
+      sources {
+        c {
+          source {
+              srcDir "./examples"
+              include "dwebp.c"
+          }
+        }
+      }
+    }
+
+    webpmux_example(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "imageio_util", linkage: "static"
+          lib library: "webpmux", linkage: "static"
+          lib library: "webp"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "webpmux.c"
+          }
+        }
+      }
+    }
+
+    img2webp_example(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "imagedec", linkage: "static"
+          lib library: "imageio_util", linkage: "static"
+          lib library: "webpmux", linkage: "static"
+          lib library: "webpdemux", linkage: "static"
+          lib library: "webp"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "img2webp.c"
+          }
+        }
+      }
+    }
+
+    webpinfo_example(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "imageio_util", linkage: "static"
+          lib library: "webp"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "webpinfo.c"
+          }
+        }
+      }
+    }
+  }
+  tasks {
+    // Task to test all possible configurations.
+    buildAllExecutables(Task) {
+      dependsOn $.binaries.findAll { it.buildable }
+    }
+  }
+}
--- a/external/libwebp/libwebp/cmake/WebPConfig.cmake.in
+++ b/external/libwebp/libwebp/cmake/WebPConfig.cmake.in
@@ -0,0 +1,18 @@
+set(WebP_VERSION @PROJECT_VERSION@)
+set(WEBP_VERSION ${WebP_VERSION})
+
+@PACKAGE_INIT@
+
+if(@WEBP_USE_THREAD@)
+  include(CMakeFindDependencyMacro)
+  find_dependency(Threads REQUIRED)
+endif()
+
+include("${CMAKE_CURRENT_LIST_DIR}/@PROJECT_NAME@Targets.cmake")
+
+set_and_check(WebP_INCLUDE_DIR "@PACKAGE_CMAKE_INSTALL_INCLUDEDIR@")
+set(WEBP_INCLUDE_DIRS ${WebP_INCLUDE_DIRS})
+set(WebP_LIBRARIES "@INSTALLED_LIBRARIES@")
+set(WEBP_LIBRARIES "${WebP_LIBRARIES}")
+
+check_required_components(WebP)
--- a/external/libwebp/libwebp/cmake/config.h.in
+++ b/external/libwebp/libwebp/cmake/config.h.in
@@ -0,0 +1,116 @@
+/* Adapted from the autotools src/webp/config.h.in.  */
+
+/* Define if building universal (internal helper macro) */
+/* TODO: handle properly in CMake */
+#cmakedefine AC_APPLE_UNIVERSAL_BUILD 1
+
+/* Set to 1 if __builtin_bswap16 is available */
+#cmakedefine HAVE_BUILTIN_BSWAP16 1
+
+/* Set to 1 if __builtin_bswap32 is available */
+#cmakedefine HAVE_BUILTIN_BSWAP32 1
+
+/* Set to 1 if __builtin_bswap64 is available */
+#cmakedefine HAVE_BUILTIN_BSWAP64 1
+
+/* Define to 1 if you have the <cpu-features.h> header file. */
+#cmakedefine HAVE_CPU_FEATURES_H 1
+
+/* Define to 1 if you have the <GLUT/glut.h> header file. */
+#cmakedefine HAVE_GLUT_GLUT_H 1
+
+/* Define to 1 if you have the <GL/glut.h> header file. */
+#cmakedefine HAVE_GL_GLUT_H 1
+
+/* Define to 1 if you have the <OpenGL/glut.h> header file. */
+#cmakedefine HAVE_OPENGL_GLUT_H 1
+
+/* Define to 1 if you have the <shlwapi.h> header file. */
+#cmakedefine HAVE_SHLWAPI_H 1
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#cmakedefine HAVE_UNISTD_H 1
+
+/* Define to 1 if you have the <wincodec.h> header file. */
+#cmakedefine HAVE_WINCODEC_H 1
+
+/* Define to 1 if you have the <windows.h> header file. */
+#cmakedefine HAVE_WINDOWS_H 1
+
+/* Define to the sub-directory in which libtool stores uninstalled libraries.
+   */
+/* TODO: handle properly in CMake */
+#cmakedefine LT_OBJDIR "@LT_OBJDIR@"
+
+/* Name of package */
+#cmakedefine PACKAGE "@PROJECT_NAME@"
+
+/* Define to the address where bug reports for this package should be sent. */
+#cmakedefine PACKAGE_BUGREPORT "@PACKAGE_BUGREPORT@"
+
+/* Define to the full name of this package. */
+#cmakedefine PACKAGE_NAME "@PACKAGE_NAME@"
+
+/* Define to the full name and version of this package. */
+#cmakedefine PACKAGE_STRING "@PACKAGE_STRING@"
+
+/* Define to the one symbol short name of this package. */
+#cmakedefine PACKAGE_TARNAME "@PACKAGE_TARNAME@"
+
+/* Define to the home page for this package. */
+#cmakedefine PACKAGE_URL "@PACKAGE_URL@"
+
+/* Define to the version of this package. */
+#cmakedefine PACKAGE_VERSION "@PACKAGE_VERSION@"
+
+/* Version number of package */
+#cmakedefine VERSION "@VERSION@"
+
+/* Set to 1 if GIF library is installed */
+#cmakedefine WEBP_HAVE_GIF 1
+
+/* Set to 1 if OpenGL is supported */
+#cmakedefine WEBP_HAVE_GL 1
+
+/* Set to 1 if JPEG library is installed */
+#cmakedefine WEBP_HAVE_JPEG 1
+
+/* Set to 1 if NEON is supported */
+#cmakedefine WEBP_HAVE_NEON
+
+/* Set to 1 if runtime detection of NEON is enabled */
+/* TODO: handle properly in CMake */
+#cmakedefine WEBP_HAVE_NEON_RTCD
+
+/* Set to 1 if PNG library is installed */
+#cmakedefine WEBP_HAVE_PNG 1
+
+/* Set to 1 if SDL library is installed */
+#cmakedefine WEBP_HAVE_SDL 1
+
+/* Set to 1 if SSE2 is supported */
+#cmakedefine WEBP_HAVE_SSE2 1
+
+/* Set to 1 if SSE4.1 is supported */
+#cmakedefine WEBP_HAVE_SSE41 1
+
+/* Set to 1 if TIFF library is installed */
+#cmakedefine WEBP_HAVE_TIFF 1
+
+/* Enable near lossless encoding */
+#cmakedefine WEBP_NEAR_LOSSLESS 1
+
+/* Undefine this to disable thread support. */
+#cmakedefine WEBP_USE_THREAD 1
+
+/* Define WORDS_BIGENDIAN to 1 if your processor stores words with the most
+   significant byte first (like Motorola and SPARC, unlike Intel). */
+#if defined AC_APPLE_UNIVERSAL_BUILD
+# if defined __BIG_ENDIAN__
+#  define WORDS_BIGENDIAN 1
+# endif
+#else
+# ifndef WORDS_BIGENDIAN
+#  undef WORDS_BIGENDIAN
+# endif
+#endif
--- a/external/libwebp/libwebp/cmake/cpu.cmake
+++ b/external/libwebp/libwebp/cmake/cpu.cmake
@@ -0,0 +1,159 @@
+#  Copyright (c) 2021 Google LLC.
+#
+#  Use of this source code is governed by a BSD-style license
+#  that can be found in the LICENSE file in the root of the source
+#  tree. An additional intellectual property rights grant can be found
+#  in the file PATENTS.  All contributing project authors may
+#  be found in the AUTHORS file in the root of the source tree.
+
+# Check for SIMD extensions.
+include(CMakePushCheckState)
+
+function(webp_check_compiler_flag WEBP_SIMD_FLAG ENABLE_SIMD)
+  if(NOT ENABLE_SIMD)
+    message(STATUS "Disabling ${WEBP_SIMD_FLAG} optimization.")
+    set(WEBP_HAVE_${WEBP_SIMD_FLAG} 0 PARENT_SCOPE)
+    return()
+  endif()
+  unset(WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG} CACHE)
+  cmake_push_check_state()
+  set(CMAKE_REQUIRED_INCLUDES ${CMAKE_CURRENT_SOURCE_DIR})
+  check_c_source_compiles(
+    "
+      #include \"${CMAKE_CURRENT_LIST_DIR}/../src/dsp/dsp.h\"
+      int main(void) {
+        #if !defined(WEBP_USE_${WEBP_SIMD_FLAG})
+        this is not valid code
+        #endif
+        return 0;
+      }
+    "
+    WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG})
+  cmake_pop_check_state()
+  if(WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG})
+    set(WEBP_HAVE_${WEBP_SIMD_FLAG} 1 PARENT_SCOPE)
+  else()
+    set(WEBP_HAVE_${WEBP_SIMD_FLAG} 0 PARENT_SCOPE)
+  endif()
+endfunction()
+
+# those are included in the names of WEBP_USE_* in c++ code.
+set(WEBP_SIMD_FLAGS "SSE41;SSE2;MIPS32;MIPS_DSP_R2;NEON;MSA")
+set(WEBP_SIMD_FILE_EXTENSIONS
+    "_sse41.c;_sse2.c;_mips32.c;_mips_dsp_r2.c;_neon.c;_msa.c")
+if(MSVC AND CMAKE_C_COMPILER_ID STREQUAL "MSVC")
+  # With at least Visual Studio 12 (2013)+ /arch is not necessary to build SSE2
+  # or SSE4 code unless a lesser /arch is forced. MSVC does not have a SSE4
+  # flag, but an AVX one. Using that with SSE4 code risks generating illegal
+  # instructions when used on machines with SSE4 only. The flags are left for
+  # older (untested) versions to avoid any potential compatibility issues.
+  if(MSVC_VERSION GREATER_EQUAL 1800 AND NOT CMAKE_C_FLAGS MATCHES "/arch:")
+    set(SIMD_ENABLE_FLAGS)
+  else()
+    set(SIMD_ENABLE_FLAGS "/arch:AVX;/arch:SSE2;;;;")
+  endif()
+  set(SIMD_DISABLE_FLAGS)
+else()
+  set(SIMD_ENABLE_FLAGS "-msse4.1;-msse2;-mips32;-mdspr2;-mfpu=neon;-mmsa")
+  set(SIMD_DISABLE_FLAGS "-mno-sse4.1;-mno-sse2;;-mno-dspr2;;-mno-msa")
+endif()
+
+set(WEBP_SIMD_FILES_TO_INCLUDE)
+set(WEBP_SIMD_FLAGS_TO_INCLUDE)
+
+if(${ANDROID})
+  if(${ANDROID_ABI} STREQUAL "armeabi-v7a")
+    # This is because Android studio uses the configuration "-march=armv7-a
+    # -mfloat-abi=softfp -mfpu=vfpv3-d16" that does not trigger neon
+    # optimizations but should (as this configuration does not exist anymore).
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mfpu=neon ")
+  endif()
+endif()
+
+list(LENGTH WEBP_SIMD_FLAGS WEBP_SIMD_FLAGS_LENGTH)
+math(EXPR WEBP_SIMD_FLAGS_RANGE "${WEBP_SIMD_FLAGS_LENGTH} - 1")
+
+foreach(I_SIMD RANGE ${WEBP_SIMD_FLAGS_RANGE})
+  # With Emscripten 2.0.9 -msimd128 -mfpu=neon will enable NEON, but the source
+  # will fail to compile.
+  if(EMSCRIPTEN AND ${I_SIMD} GREATER_EQUAL 2)
+    break()
+  endif()
+
+  list(GET WEBP_SIMD_FLAGS ${I_SIMD} WEBP_SIMD_FLAG)
+
+  # First try with no extra flag added as the compiler might have default flags
+  # (especially on Android).
+  unset(WEBP_HAVE_${WEBP_SIMD_FLAG} CACHE)
+  cmake_push_check_state()
+  set(CMAKE_REQUIRED_FLAGS)
+  webp_check_compiler_flag(${WEBP_SIMD_FLAG} ${WEBP_ENABLE_SIMD})
+  if(NOT WEBP_HAVE_${WEBP_SIMD_FLAG})
+    list(GET SIMD_ENABLE_FLAGS ${I_SIMD} SIMD_COMPILE_FLAG)
+    if(EMSCRIPTEN)
+      set(SIMD_COMPILE_FLAG "-msimd128 ${SIMD_COMPILE_FLAG}")
+    endif()
+    set(CMAKE_REQUIRED_FLAGS ${SIMD_COMPILE_FLAG})
+    webp_check_compiler_flag(${WEBP_SIMD_FLAG} ${WEBP_ENABLE_SIMD})
+  else()
+    if(MSVC AND SIMD_ENABLE_FLAGS)
+      # The detection for SSE2/SSE4 support under MSVC is based on the compiler
+      # version so e.g., clang-cl will require flags to enable the assembly.
+      list(GET SIMD_ENABLE_FLAGS ${I_SIMD} SIMD_COMPILE_FLAG)
+    else()
+      set(SIMD_COMPILE_FLAG " ")
+    endif()
+  endif()
+  # Check which files we should include or not.
+  list(GET WEBP_SIMD_FILE_EXTENSIONS ${I_SIMD} WEBP_SIMD_FILE_EXTENSION)
+  file(GLOB SIMD_FILES "${CMAKE_CURRENT_LIST_DIR}/../"
+       "src/dsp/*${WEBP_SIMD_FILE_EXTENSION}")
+  if(WEBP_HAVE_${WEBP_SIMD_FLAG})
+    # Memorize the file and flags.
+    foreach(FILE ${SIMD_FILES})
+      list(APPEND WEBP_SIMD_FILES_TO_INCLUDE ${FILE})
+      list(APPEND WEBP_SIMD_FLAGS_TO_INCLUDE ${SIMD_COMPILE_FLAG})
+    endforeach()
+  else()
+    # Remove the file from the list.
+    foreach(FILE ${SIMD_FILES})
+      list(APPEND WEBP_SIMD_FILES_NOT_TO_INCLUDE ${FILE})
+    endforeach()
+    # Explicitly disable SIMD.
+    if(SIMD_DISABLE_FLAGS)
+      list(GET SIMD_DISABLE_FLAGS ${I_SIMD} SIMD_COMPILE_FLAG)
+      include(CheckCCompilerFlag)
+      if(SIMD_COMPILE_FLAG)
+        # Between 3.17.0 and 3.18.2 check_cxx_compiler_flag() sets a normal
+        # variable at parent scope while check_cxx_source_compiles() continues
+        # to set an internal cache variable, so we unset both to avoid the
+        # failure / success state persisting between checks. See
+        # https://gitlab.kitware.com/cmake/cmake/-/issues/21207.
+        unset(HAS_COMPILE_FLAG)
+        unset(HAS_COMPILE_FLAG CACHE)
+        check_c_compiler_flag(${SIMD_COMPILE_FLAG} HAS_COMPILE_FLAG)
+        if(HAS_COMPILE_FLAG)
+          # Do one more check for Clang to circumvent CMake issue 13194.
+          if(COMMAND check_compiler_flag_common_patterns)
+            # Only in CMake 3.0 and above.
+            check_compiler_flag_common_patterns(COMMON_PATTERNS)
+          else()
+            set(COMMON_PATTERNS)
+          endif()
+          set(CMAKE_REQUIRED_DEFINITIONS ${SIMD_COMPILE_FLAG})
+          check_c_source_compiles(
+            "int main(void) {return 0;}" FLAG_${SIMD_COMPILE_FLAG} FAIL_REGEX
+            "warning: argument unused during compilation:" ${COMMON_PATTERNS})
+          if(NOT FLAG_${SIMD_COMPILE_FLAG})
+            unset(HAS_COMPILE_FLAG)
+            unset(HAS_COMPILE_FLAG CACHE)
+          endif()
+        endif()
+        if(HAS_COMPILE_FLAG)
+          set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${SIMD_COMPILE_FLAG}")
+        endif()
+      endif()
+    endif()
+  endif()
+  cmake_pop_check_state()
+endforeach()
--- a/external/libwebp/libwebp/cmake/deps.cmake
+++ b/external/libwebp/libwebp/cmake/deps.cmake
@@ -0,0 +1,172 @@
+#  Copyright (c) 2021 Google LLC.
+#
+#  Use of this source code is governed by a BSD-style license
+#  that can be found in the LICENSE file in the root of the source
+#  tree. An additional intellectual property rights grant can be found
+#  in the file PATENTS.  All contributing project authors may
+#  be found in the AUTHORS file in the root of the source tree.
+
+# Generate the config.h to compile with specific intrinsics / libs.
+
+# Check for compiler options.
+include(CheckCSourceCompiles)
+check_c_source_compiles(
+  "
+    int main(void) {
+      (void)__builtin_bswap16(0);
+      return 0;
+    }
+  "
+  HAVE_BUILTIN_BSWAP16)
+check_c_source_compiles(
+  "
+    int main(void) {
+      (void)__builtin_bswap32(0);
+      return 0;
+    }
+  "
+  HAVE_BUILTIN_BSWAP32)
+check_c_source_compiles(
+  "
+    int main(void) {
+      (void)__builtin_bswap64(0);
+      return 0;
+    }
+  "
+  HAVE_BUILTIN_BSWAP64)
+
+# Check for libraries.
+if(WEBP_USE_THREAD)
+  find_package(Threads)
+  if(Threads_FOUND)
+    # work around cmake bug on QNX (https://cmake.org/Bug/view.php?id=11333)
+    if(CMAKE_USE_PTHREADS_INIT AND NOT CMAKE_SYSTEM_NAME STREQUAL "QNX")
+      set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pthread")
+    endif()
+    list(APPEND WEBP_DEP_LIBRARIES Threads::Threads)
+  endif()
+  set(WEBP_USE_THREAD ${Threads_FOUND})
+endif()
+
+# TODO: this seems unused, check with autotools.
+set(LT_OBJDIR ".libs/")
+
+# Only useful for vwebp, so useless for now.
+find_package(OpenGL)
+set(WEBP_HAVE_GL ${OPENGL_FOUND})
+
+# Check if we need to link to the C math library. We do not look for it as it is
+# not found when cross-compiling, while it is here.
+check_c_source_compiles(
+  "
+    #include <math.h>
+    int main(int argc, char** argv) {
+      return (int)pow(argc, 2.5);
+    }
+  "
+  HAVE_MATH_LIBRARY)
+if(NOT HAVE_MATH_LIBRARY)
+  message(STATUS "Adding -lm flag.")
+  list(APPEND SHARPYUV_DEP_LIBRARIES m)
+  list(APPEND WEBP_DEP_LIBRARIES m)
+endif()
+
+# Find the standard image libraries.
+set(WEBP_DEP_IMG_LIBRARIES)
+set(WEBP_DEP_IMG_INCLUDE_DIRS)
+if(WEBP_FIND_IMG_LIBS)
+  foreach(I_LIB PNG JPEG TIFF)
+    # Disable tiff when compiling in static mode as it is failing on Ubuntu.
+    if(WEBP_LINK_STATIC AND ${I_LIB} STREQUAL "TIFF")
+      message(STATUS "TIFF is disabled when statically linking.")
+      continue()
+    endif()
+    find_package(${I_LIB})
+    set(WEBP_HAVE_${I_LIB} ${${I_LIB}_FOUND})
+    if(${I_LIB}_FOUND)
+      list(APPEND WEBP_DEP_IMG_LIBRARIES ${${I_LIB}_LIBRARIES})
+      list(APPEND WEBP_DEP_IMG_INCLUDE_DIRS ${${I_LIB}_INCLUDE_DIR}
+           ${${I_LIB}_INCLUDE_DIRS})
+    endif()
+  endforeach()
+  if(WEBP_DEP_IMG_INCLUDE_DIRS)
+    list(REMOVE_DUPLICATES WEBP_DEP_IMG_INCLUDE_DIRS)
+  endif()
+
+  # GIF detection, gifdec isn't part of the imageio lib.
+  include(CMakePushCheckState)
+  set(WEBP_DEP_GIF_LIBRARIES)
+  set(WEBP_DEP_GIF_INCLUDE_DIRS)
+  find_package(GIF)
+  set(WEBP_HAVE_GIF ${GIF_FOUND})
+  if(GIF_FOUND)
+    # GIF find_package only locates the header and library, it doesn't fail
+    # compile tests when detecting the version, but falls back to 3 (as of at
+    # least cmake 3.7.2). Make sure the library links to avoid incorrect
+    # detection when cross compiling.
+    cmake_push_check_state()
+    set(CMAKE_REQUIRED_LIBRARIES ${GIF_LIBRARIES})
+    set(CMAKE_REQUIRED_INCLUDES ${GIF_INCLUDE_DIR})
+    check_c_source_compiles(
+      "
+      #include <gif_lib.h>
+      int main(void) {
+        (void)DGifOpenFileHandle;
+        return 0;
+      }
+      "
+      GIF_COMPILES)
+    cmake_pop_check_state()
+    if(GIF_COMPILES)
+      list(APPEND WEBP_DEP_GIF_LIBRARIES ${GIF_LIBRARIES})
+      list(APPEND WEBP_DEP_GIF_INCLUDE_DIRS ${GIF_INCLUDE_DIR})
+    else()
+      unset(GIF_FOUND)
+    endif()
+  endif()
+endif()
+
+# Check for specific headers.
+include(CheckIncludeFiles)
+check_include_files(GLUT/glut.h HAVE_GLUT_GLUT_H)
+check_include_files(GL/glut.h HAVE_GL_GLUT_H)
+check_include_files(OpenGL/glut.h HAVE_OPENGL_GLUT_H)
+check_include_files(shlwapi.h HAVE_SHLWAPI_H)
+check_include_files(unistd.h HAVE_UNISTD_H)
+check_include_files(wincodec.h HAVE_WINCODEC_H)
+check_include_files(windows.h HAVE_WINDOWS_H)
+
+# Windows specifics
+if(HAVE_WINCODEC_H)
+  list(APPEND WEBP_DEP_LIBRARIES shlwapi ole32 windowscodecs)
+endif()
+
+# Check for SIMD extensions.
+include(${CMAKE_CURRENT_LIST_DIR}/cpu.cmake)
+
+# Define extra info.
+set(PACKAGE ${PROJECT_NAME})
+set(PACKAGE_NAME ${PROJECT_NAME})
+
+# Read from configure.ac.
+file(READ ${CMAKE_CURRENT_SOURCE_DIR}/configure.ac CONFIGURE_AC)
+string(REGEX MATCHALL "\\[([0-9a-z\\.:/]*)\\]" CONFIGURE_AC_PACKAGE_INFO
+             ${CONFIGURE_AC})
+function(strip_bracket VAR)
+  string(LENGTH ${${VAR}} TMP_LEN)
+  math(EXPR TMP_LEN ${TMP_LEN}-2)
+  string(SUBSTRING ${${VAR}} 1 ${TMP_LEN} TMP_SUB)
+  set(${VAR} ${TMP_SUB} PARENT_SCOPE)
+endfunction()
+
+list(GET CONFIGURE_AC_PACKAGE_INFO 1 PACKAGE_VERSION)
+strip_bracket(PACKAGE_VERSION)
+list(GET CONFIGURE_AC_PACKAGE_INFO 2 PACKAGE_BUGREPORT)
+strip_bracket(PACKAGE_BUGREPORT)
+list(GET CONFIGURE_AC_PACKAGE_INFO 3 PACKAGE_URL)
+strip_bracket(PACKAGE_URL)
+
+# Build more info.
+set(PACKAGE_STRING "${PACKAGE_NAME} ${PACKAGE_VERSION}")
+set(PACKAGE_TARNAME ${PACKAGE_NAME})
+set(VERSION ${PACKAGE_VERSION})
--- a/external/libwebp/libwebp/codereview.settings
+++ b/external/libwebp/libwebp/codereview.settings
@@ -0,0 +1,4 @@
+# This file is used by git cl to get repository specific information.
+GERRIT_HOST: True
+CODE_REVIEW_SERVER: chromium-review.googlesource.com
+GERRIT_SQUASH_UPLOADS: False
--- a/external/libwebp/libwebp/configure.ac
+++ b/external/libwebp/libwebp/configure.ac
@@ -0,0 +1,803 @@
+AC_INIT([libwebp], [1.3.1],
+        [https://bugs.chromium.org/p/webp],,
+        [https://developers.google.com/speed/webp])
+AC_CANONICAL_HOST
+AC_PREREQ([2.60])
+AM_INIT_AUTOMAKE([-Wall foreign subdir-objects])
+
+dnl === automake >= 1.12 requires this for 'unusual archivers' support.
+dnl === it must occur before LT_INIT (AC_PROG_LIBTOOL).
+m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
+
+dnl === AC_PROG_LIBTOOL is deprecated.
+m4_ifdef([LT_INIT], [LT_INIT], [AC_PROG_LIBTOOL])
+AC_PROG_SED
+AM_PROG_CC_C_O
+
+dnl === Enable less verbose output when building.
+m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
+
+dnl == test endianness
+AC_C_BIGENDIAN
+
+dnl === SET_IF_UNSET(shell_var, value)
+dnl ===   Set the shell variable 'shell_var' to 'value' if it is unset.
+AC_DEFUN([SET_IF_UNSET], [test "${$1+set}" = "set" || $1=$2])
+
+AC_ARG_ENABLE([everything],
+              AS_HELP_STRING([--enable-everything],
+                             [Enable all optional targets. These can still be
+                              disabled with --disable-target]),
+              [SET_IF_UNSET([enable_libsharpyuv], [$enableval])
+               SET_IF_UNSET([enable_libwebpdecoder], [$enableval])
+               SET_IF_UNSET([enable_libwebpdemux], [$enableval])
+               SET_IF_UNSET([enable_libwebpextras], [$enableval])
+               SET_IF_UNSET([enable_libwebpmux], [$enableval])])
+
+dnl === Check whether libwebpmux should be built
+AC_MSG_CHECKING(whether libwebpmux is to be built)
+AC_ARG_ENABLE([libwebpmux],
+              AS_HELP_STRING([--disable-libwebpmux],
+                             [Disable libwebpmux @<:@default=no@:>@]),
+              [], [enable_libwebpmux=yes])
+AC_MSG_RESULT(${enable_libwebpmux-no})
+AM_CONDITIONAL([BUILD_MUX], [test "$enable_libwebpmux" = "yes"])
+
+dnl === Check whether libwebpdemux should be built
+AC_MSG_CHECKING(whether libwebpdemux is to be built)
+AC_ARG_ENABLE([libwebpdemux],
+              AS_HELP_STRING([--disable-libwebpdemux],
+                             [Disable libwebpdemux @<:@default=no@:>@]),
+              [], [enable_libwebpdemux=yes])
+AC_MSG_RESULT(${enable_libwebpdemux-no})
+AM_CONDITIONAL([BUILD_DEMUX], [test "$enable_libwebpdemux" = "yes"])
+
+dnl === Check whether decoder library should be built.
+AC_MSG_CHECKING(whether decoder library is to be built)
+AC_ARG_ENABLE([libwebpdecoder],
+              AS_HELP_STRING([--enable-libwebpdecoder],
+                             [Build libwebpdecoder @<:@default=no@:>@]))
+AC_MSG_RESULT(${enable_libwebpdecoder-no})
+AM_CONDITIONAL([BUILD_LIBWEBPDECODER], [test "$enable_libwebpdecoder" = "yes"])
+
+dnl === Check whether libwebpextras should be built
+AC_MSG_CHECKING(whether libwebpextras is to be built)
+AC_ARG_ENABLE([libwebpextras],
+              AS_HELP_STRING([--enable-libwebpextras],
+                             [Build libwebpextras @<:@default=no@:>@]))
+AC_MSG_RESULT(${enable_libwebpextras-no})
+AM_CONDITIONAL([BUILD_EXTRAS], [test "$enable_libwebpextras" = "yes"])
+
+dnl === If --enable-asserts is not defined, define NDEBUG
+
+AC_MSG_CHECKING(whether asserts are enabled)
+AC_ARG_ENABLE([asserts],
+              AS_HELP_STRING([--enable-asserts],
+                             [Enable assert checks]))
+if test "x${enable_asserts-no}" = "xno"; then
+  AM_CPPFLAGS="${AM_CPPFLAGS} -DNDEBUG"
+fi
+AC_MSG_RESULT(${enable_asserts-no})
+AC_SUBST([AM_CPPFLAGS])
+
+AC_ARG_WITH([pkgconfigdir], AS_HELP_STRING([--with-pkgconfigdir=DIR],
+            [Path to the pkgconfig directory @<:@LIBDIR/pkgconfig@:>@]),
+            [pkgconfigdir="$withval"], [pkgconfigdir='${libdir}/pkgconfig'])
+AC_SUBST([pkgconfigdir])
+
+dnl === TEST_AND_ADD_CFLAGS(var, flag)
+dnl ===   Checks whether $CC supports 'flag' and adds it to 'var'
+dnl ===   on success.
+AC_DEFUN([TEST_AND_ADD_CFLAGS],
+         [SAVED_CFLAGS="$CFLAGS"
+          CFLAGS="-Werror $2"
+          AC_MSG_CHECKING([whether $CC supports $2])
+          dnl Note AC_LANG_PROGRAM([]) uses an old-style main definition.
+          AC_COMPILE_IFELSE([AC_LANG_SOURCE([int main(void) { return 0; }])],
+                            [AC_MSG_RESULT([yes])]
+                            dnl Simply append the variable avoiding a
+                            dnl compatibility ifdef for AS_VAR_APPEND as this
+                            dnl variable shouldn't grow all that large.
+                            [$1="${$1} $2"],
+                            [AC_MSG_RESULT([no])])
+          CFLAGS="$SAVED_CFLAGS"])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-fvisibility=hidden])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wall])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wconstant-conversion])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wdeclaration-after-statement])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wextra])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wfloat-conversion])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wformat -Wformat-nonliteral])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wformat -Wformat-security])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wmissing-declarations])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wmissing-prototypes])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wold-style-definition])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wparentheses-equality])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wshadow])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wshorten-64-to-32])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wundef])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wunreachable-code-aggressive])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wunreachable-code])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wunused-but-set-variable])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wunused])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wvla])
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62040
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61622
+AS_IF([test "$GCC" = "yes" ], [
+       gcc_version=`$CC -dumpversion`
+       gcc_wht_bug=""
+       case "$host_cpu" in
+         aarch64|arm64)
+          case "$gcc_version" in
+            4.9|4.9.0|4.9.1) gcc_wht_bug=yes ;;
+          esac
+       esac
+       AS_IF([test "$gcc_wht_bug" = "yes"], [
+              TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-frename-registers])])])
+# Use -flax-vector-conversions, if available, when building intrinsics with
+# older versions of gcc. The flag appeared in 4.3.x, but if backported, and
+# -fno-lax-vector-conversions is set, errors may occur with the intrinsics
+# files along with the older system includes, e.g., emmintrin.h.
+# Originally observed with cc (GCC) 4.2.1 20070831 patched [FreeBSD] (9.3).
+# https://bugs.chromium.org/p/webp/issues/detail?id=274
+AS_IF([test "$GCC" = "yes" ], [
+       case "$host_cpu" in
+         amd64|i?86|x86_64)
+           AC_COMPILE_IFELSE(
+             dnl only check for -flax-vector-conversions with older gcc, skip
+             dnl clang as it reports itself as 4.2.1, but the flag isn't needed.
+             [AC_LANG_SOURCE([#if !defined(__clang__) && defined(__GNUC__) && \
+                                  ((__GNUC__ << 8) | __GNUC_MINOR__) < 0x403
+                              #error old gcc
+                              #endif
+                              int main(void) { return 0; }
+                             ])],,
+              [TEST_AND_ADD_CFLAGS([INTRINSICS_CFLAGS],
+                                   [-flax-vector-conversions])])
+           ;;
+       esac])
+AC_SUBST([AM_CFLAGS])
+
+dnl === Check for machine specific flags
+AC_ARG_ENABLE([sse4.1],
+              AS_HELP_STRING([--disable-sse4.1],
+                             [Disable detection of SSE4.1 support
+                              @<:@default=auto@:>@]))
+
+AS_IF([test "x$enable_sse4_1" != "xno" -a "x$enable_sse2" != "xno"], [
+  SSE41_FLAGS="$INTRINSICS_CFLAGS $SSE41_FLAGS"
+  TEST_AND_ADD_CFLAGS([SSE41_FLAGS], [-msse4.1])
+  AS_IF([test -n "$SSE41_FLAGS"], [
+    SAVED_CFLAGS=$CFLAGS
+    CFLAGS="$CFLAGS $SSE41_FLAGS"
+    AC_CHECK_HEADER([smmintrin.h],
+                    [AC_DEFINE(WEBP_HAVE_SSE41, [1],
+                     [Set to 1 if SSE4.1 is supported])],
+                    [SSE41_FLAGS=""])
+    CFLAGS=$SAVED_CFLAGS])
+  AC_SUBST([SSE41_FLAGS])])
+
+AC_ARG_ENABLE([sse2],
+              AS_HELP_STRING([--disable-sse2],
+                             [Disable detection of SSE2 support
+                              @<:@default=auto@:>@]))
+
+AS_IF([test "x$enable_sse2" != "xno"], [
+  SSE2_FLAGS="$INTRINSICS_CFLAGS $SSE2_FLAGS"
+  TEST_AND_ADD_CFLAGS([SSE2_FLAGS], [-msse2])
+  AS_IF([test -n "$SSE2_FLAGS"], [
+    SAVED_CFLAGS=$CFLAGS
+    CFLAGS="$CFLAGS $SSE2_FLAGS"
+    AC_CHECK_HEADER([emmintrin.h],
+                    [AC_DEFINE(WEBP_HAVE_SSE2, [1],
+                     [Set to 1 if SSE2 is supported])],
+                    [SSE2_FLAGS=""])
+    CFLAGS=$SAVED_CFLAGS])
+  AC_SUBST([SSE2_FLAGS])])
+
+AC_ARG_ENABLE([neon],
+              AS_HELP_STRING([--disable-neon],
+                             [Disable detection of NEON support
+                              @<:@default=auto@:>@]))
+
+AC_ARG_ENABLE([neon_rtcd],
+              AS_HELP_STRING([--disable-neon-rtcd],
+                             [Disable runtime detection of NEON support via
+                              /proc/cpuinfo on Linux hosts
+                              @<:@default=auto@:>@]))
+# For ARM(7) hosts:
+# Both NEON flags unset and NEON support detected = build all modules with NEON
+# NEON detected with the use of -mfpu=neon = build only NEON modules with NEON
+AS_IF([test "x$enable_neon" != "xno"], [
+  case "$host_cpu" in
+    arm|armv7*)
+      # Test for NEON support without flags before falling back to -mfpu=neon
+      for flag in '' '-mfpu=neon'; do
+        LOCAL_NEON_FLAGS="$INTRINSICS_CFLAGS $NEON_FLAGS"
+        TEST_AND_ADD_CFLAGS([LOCAL_NEON_FLAGS], [$flag])
+        SAVED_CFLAGS=$CFLAGS
+        CFLAGS="$CFLAGS $LOCAL_NEON_FLAGS"
+
+        dnl Note AC_LANG_PROGRAM([]) uses an old-style main definition.
+        AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+          #include <arm_neon.h>
+          int main(void) {
+            int8x8_t v = vdup_n_s8(0);
+            (void)v;
+            return 0;
+          }])],
+          [NEON_FLAGS="$(echo $LOCAL_NEON_FLAGS | $SED 's/^ *//')"
+           AS_IF([test -n "$NEON_FLAGS"], [
+             AS_IF([test "${host_os%%-*}" = "linux" -o \
+                         "x$enable_neon_rtcd" = "xno"], [
+               CFLAGS=$SAVED_CFLAGS
+               AC_DEFINE(WEBP_HAVE_NEON, [1], [Set to 1 if NEON is supported])
+               break
+             ],[
+               AC_MSG_WARN(m4_normalize([NEON runtime cpu-detection is
+                                         unavailable for ${host_os%%-*}. Force
+                                         with CFLAGS=-mfpu=neon or
+                                         --disable-neon-rtcd.]))
+               enable_neon_rtcd=no
+               NEON_FLAGS=""
+             ])
+           ],[
+             CFLAGS=$SAVED_CFLAGS
+             AC_DEFINE(WEBP_HAVE_NEON, [1], [Set to 1 if NEON is supported])
+             break
+           ])])
+        CFLAGS=$SAVED_CFLAGS
+      done
+
+      AS_IF([test -n "$NEON_FLAGS"], [
+        # If NEON is available and rtcd is disabled apply NEON_FLAGS globally.
+        AS_IF([test "x$enable_neon_rtcd" = "xno"], [
+          AM_CFLAGS="$AM_CFLAGS $NEON_FLAGS"
+          NEON_FLAGS=""],
+          [AC_DEFINE(WEBP_HAVE_NEON_RTCD, [1],
+                     [Set to 1 if runtime detection of NEON is enabled])])])
+
+      case "$host_os" in
+        *android*) AC_CHECK_HEADERS([cpu-features.h]) ;;
+      esac
+      ;;
+    aarch64*|arm64*)
+      AC_DEFINE(WEBP_HAVE_NEON, [1], [Set to 1 if NEON is supported])
+      ;;
+  esac
+  AC_SUBST([NEON_FLAGS])])
+
+dnl === CLEAR_LIBVARS([var_pfx])
+dnl ===   Clears <var_pfx>_{INCLUDES,LIBS}.
+AC_DEFUN([CLEAR_LIBVARS], [$1_INCLUDES=""; $1_LIBS=""])
+
+dnl === WITHLIB_OPTION([opt_pfx], [outvar_pfx])
+dnl ===   Defines --with-<opt_pfx>{include,lib}dir options which set
+dnl ===   the variables <outvar_pfx>_{INCLUDES,LIBS}.
+AC_DEFUN([WITHLIB_OPTION],
+  [AC_ARG_WITH([$1includedir],
+               AS_HELP_STRING([--with-$1includedir=DIR],
+                              [use $2 includes from DIR]),
+               $2_INCLUDES="-I$withval")
+   AC_ARG_WITH([$1libdir],
+               AS_HELP_STRING([--with-$1libdir=DIR],
+                              [use $2 libraries from DIR]),
+               [$2_LIBS="-L$withval"])])
+
+dnl === LIBCHECK_PROLOGUE([var_pfx])
+dnl ===   Caches the current values of CPPFLAGS/LIBS in SAVED_* then
+dnl ===   prepends the current values with <var_pfx>_{INCLUDES,LIBS}.
+AC_DEFUN([LIBCHECK_PROLOGUE],
+         [SAVED_CPPFLAGS=$CPPFLAGS
+          SAVED_LIBS=$LIBS
+          CPPFLAGS="$$1_INCLUDES $CPPFLAGS"
+          LIBS="$$1_LIBS $LIBS"])
+
+dnl === LIBCHECK_EPILOGUE([var_pfx])
+dnl ===   Restores the values of CPPFLAGS/LIBS from SAVED_* and exports
+dnl ===   <var_pfx>_{INCLUDES,LIBS} with AC_SUBST.
+AC_DEFUN([LIBCHECK_EPILOGUE],
+         [AC_SUBST($1_LIBS)
+          AC_SUBST($1_INCLUDES)
+          CPPFLAGS=$SAVED_CPPFLAGS
+          LIBS=$SAVED_LIBS])
+
+dnl === Check for gcc builtins
+
+dnl === CHECK_FOR_BUILTIN([builtin], [param], [define])
+dnl ===   links a C AC_LANG_PROGRAM, with <builtin>(<param>)
+dnl ===   AC_DEFINE'ing <define> if successful.
+AC_DEFUN([CHECK_FOR_BUILTIN],
+         [AC_LANG_PUSH([C])
+          AC_MSG_CHECKING([for $1])
+          AC_LINK_IFELSE([AC_LANG_PROGRAM([], [(void)$1($2)])],
+                         [AC_MSG_RESULT([yes])
+                          AC_DEFINE([$3], [1],
+                                    [Set to 1 if $1 is available])],
+                         [AC_MSG_RESULT([no])]),
+          AC_LANG_POP])
+
+dnl AC_CHECK_FUNC doesn't work with builtin's.
+CHECK_FOR_BUILTIN([__builtin_bswap16], [1u << 15], [HAVE_BUILTIN_BSWAP16])
+CHECK_FOR_BUILTIN([__builtin_bswap32], [1u << 31], [HAVE_BUILTIN_BSWAP32])
+CHECK_FOR_BUILTIN([__builtin_bswap64], [1ull << 63], [HAVE_BUILTIN_BSWAP64])
+
+dnl === Check for pthread support
+AC_ARG_ENABLE([threading],
+              AS_HELP_STRING([--disable-threading],
+                             [Disable detection of thread support]),,
+              [enable_threading=yes])
+if test "$enable_threading" = "yes"; then
+  AC_MSG_NOTICE([checking for threading support...])
+  AX_PTHREAD([AC_DEFINE([WEBP_USE_THREAD], [1],
+                        [Undefine this to disable thread support.])
+              LIBS="$PTHREAD_LIBS $LIBS"
+              CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+              CC="$PTHREAD_CC"
+             ],
+             [AC_CHECK_FUNC([_beginthreadex],
+                            [AC_DEFINE([WEBP_USE_THREAD], [1],
+                                       [Undefine this to disable thread
+                                        support.])],
+                            [enable_threading=no])])
+fi
+AC_MSG_NOTICE([checking if threading is enabled... ${enable_threading-no}])
+
+dnl === check for OpenGL/GLUT support ===
+
+AC_ARG_ENABLE([gl], AS_HELP_STRING([--disable-gl],
+                                   [Disable detection of OpenGL support
+                                    @<:@default=auto@:>@]))
+AS_IF([test "x$enable_gl" != "xno"], [
+  CLEAR_LIBVARS([GL])
+  WITHLIB_OPTION([gl], [GL])
+
+  LIBCHECK_PROLOGUE([GL])
+
+  glut_cflags="none"
+  glut_ldflags="none"
+  case $host_os in
+    darwin*)
+      # Special case for OSX builds. Append these to give the user a chance to
+      # override with --with-gl*
+      glut_cflags="$glut_cflags|-framework GLUT -framework OpenGL"
+      glut_ldflags="$glut_ldflags|-framework GLUT -framework OpenGL"
+      # quiet deprecation warnings for glut
+      TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wno-deprecated-declarations])
+      ;;
+  esac
+
+  GLUT_SAVED_CPPFLAGS="$CPPFLAGS"
+  SAVED_IFS="$IFS"
+  IFS="|"
+  for flag in $glut_cflags; do
+    # restore IFS immediately as the autoconf macros may need the default.
+    IFS="$SAVED_IFS"
+    unset ac_cv_header_GL_glut_h
+    unset ac_cv_header_OpenGL_glut_h
+
+    case $flag in
+      none) ;;
+      *) CPPFLAGS="$flag $CPPFLAGS";;
+    esac
+    AC_CHECK_HEADERS([GL/glut.h GLUT/glut.h OpenGL/glut.h],
+                     [glut_headers=yes;
+                      test "$flag" = "none" || GL_INCLUDES="$CPPFLAGS";
+                      break])
+    CPPFLAGS="$GLUT_SAVED_CPPFLAGS"
+    test "$glut_headers" = "yes" && break
+  done
+  IFS="$SAVED_IFS"
+
+  if test "$glut_headers" = "yes"; then
+    AC_LANG_PUSH([C])
+    GLUT_SAVED_LDFLAGS="$LDFLAGS"
+    SAVED_IFS="$IFS"
+    IFS="|"
+    for flag in $glut_ldflags; do
+      # restore IFS immediately as the autoconf macros may need the default.
+      IFS="$SAVED_IFS"
+      unset ac_cv_search_glBegin
+
+      case $flag in
+        none) ;;
+        *) LDFLAGS="$flag $LDFLAGS";;
+      esac
+
+      # find libGL
+      GL_SAVED_LIBS="$LIBS"
+      AC_SEARCH_LIBS([glBegin], [GL OpenGL opengl32])
+      LIBS="$GL_SAVED_LIBS"
+
+      # A direct link to libGL may not be necessary on e.g., linux.
+      GLUT_SAVED_LIBS="$LIBS"
+      for lib in "" "-lglut" "-lglut $ac_cv_search_glBegin"; do
+        LIBS="$lib"
+        AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM([
+             #ifdef __cplusplus
+             # define EXTERN_C extern "C"
+             #else
+             # define EXTERN_C
+             #endif
+             EXTERN_C char glOrtho();
+             EXTERN_C char glutMainLoop();
+            ],[
+             glOrtho();
+             glutMainLoop();
+            ])
+          ],
+          AC_DEFINE(WEBP_HAVE_GL, [1],
+                    [Set to 1 if OpenGL is supported])
+          [glut_support=yes], []
+        )
+        if test "$glut_support" = "yes"; then
+          GL_LIBS="$LDFLAGS $lib"
+          break
+        fi
+      done
+      LIBS="$GLUT_SAVED_LIBS"
+      LDFLAGS="$GLUT_SAVED_LDFLAGS"
+      test "$glut_support" = "yes" && break
+    done
+    IFS="$SAVED_IFS"
+    AC_LANG_POP
+  fi
+
+  LIBCHECK_EPILOGUE([GL])
+
+  if test "$glut_support" = "yes" -a "$enable_libwebpdemux" = "yes"; then
+    build_vwebp=yes
+  else
+    AC_MSG_NOTICE(
+      m4_normalize([Not building vwebp.
+                    OpenGL libraries and --enable-libwebpdemux are required.]))
+  fi
+])
+AM_CONDITIONAL([BUILD_VWEBP], [test "$build_vwebp" = "yes"])
+
+dnl === check for SDL support ===
+
+AC_ARG_ENABLE([sdl],
+              AS_HELP_STRING([--disable-sdl],
+                             [Disable detection of SDL support
+                              @<:@default=auto@:>@]))
+AS_IF([test "x$enable_sdl" != "xno"], [
+  CLEAR_LIBVARS([SDL])
+  AC_PATH_PROGS([LIBSDL_CONFIG], [sdl-config])
+  if test -n "$LIBSDL_CONFIG"; then
+    SDL_INCLUDES=`$LIBSDL_CONFIG --cflags`
+    SDL_LIBS="`$LIBSDL_CONFIG --libs`"
+  fi
+
+  WITHLIB_OPTION([sdl], [SDL])
+
+  sdl_header="no"
+  LIBCHECK_PROLOGUE([SDL])
+  AC_CHECK_HEADER([SDL/SDL.h], [sdl_header="SDL/SDL.h"],
+                  [AC_CHECK_HEADER([SDL.h], [sdl_header="SDL.h"],
+                  [AC_MSG_WARN(SDL library not available - no sdl.h)])])
+  if test x"$sdl_header" != "xno"; then
+    AC_LANG_PUSH(C)
+    SDL_SAVED_LIBS="$LIBS"
+    for lib in "" "-lSDL" "-lSDLmain -lSDL"; do
+      LIBS="$SDL_SAVED_LIBS $lib"
+      # Perform a full link to ensure SDL_main is resolved if needed.
+      AC_LINK_IFELSE(
+        [AC_LANG_SOURCE([
+           #include <$sdl_header>
+           int main(int argc, char** argv) {
+             SDL_Init(0);
+             return 0;
+           }])],
+        [SDL_LIBS="$LDFLAGS $LIBS"
+         SDL_INCLUDES="$SDL_INCLUDES -DWEBP_HAVE_SDL"
+         AC_DEFINE(WEBP_HAVE_SDL, [1],
+                   [Set to 1 if SDL library is installed])
+         sdl_support=yes]
+      )
+      if test x"$sdl_support" = "xyes"; then
+        break
+      fi
+    done
+    # LIBS is restored by LIBCHECK_EPILOGUE
+    AC_LANG_POP
+    if test x"$sdl_header" = "xSDL.h"; then
+      SDL_INCLUDES="$SDL_INCLUDES -DWEBP_HAVE_JUST_SDL_H"
+    fi
+  fi
+  LIBCHECK_EPILOGUE([SDL])
+
+  if test x"$sdl_support" = "xyes"; then
+    build_vwebp_sdl=yes
+  else
+    AC_MSG_NOTICE([Not building vwebp-sdl. SDL library is required.])
+  fi
+])
+
+AM_CONDITIONAL([BUILD_VWEBP_SDL], [test "$build_vwebp_sdl" = "yes"])
+
+dnl === check for PNG support ===
+
+AC_ARG_ENABLE([png], AS_HELP_STRING([--disable-png],
+                                    [Disable detection of PNG format support
+                                     @<:@default=auto@:>@]))
+AS_IF([test "x$enable_png" != "xno"], [
+  CLEAR_LIBVARS([PNG])
+  AC_PATH_PROGS([LIBPNG_CONFIG],
+                [libpng-config libpng16-config libpng15-config libpng14-config \
+                 libpng12-config])
+  if test -n "$LIBPNG_CONFIG"; then
+    PNG_INCLUDES=`$LIBPNG_CONFIG --cflags`
+    PNG_LIBS="`$LIBPNG_CONFIG --ldflags`"
+  fi
+
+  WITHLIB_OPTION([png], [PNG])
+
+  LIBCHECK_PROLOGUE([PNG])
+  AC_CHECK_HEADER(png.h,
+    AC_SEARCH_LIBS(png_get_libpng_ver, [png],
+                   [test "$ac_cv_search_png_get_libpng_ver" = "none required" \
+                      || PNG_LIBS="$PNG_LIBS $ac_cv_search_png_get_libpng_ver"
+                    PNG_INCLUDES="$PNG_INCLUDES -DWEBP_HAVE_PNG"
+                    AC_DEFINE(WEBP_HAVE_PNG, [1],
+                              [Set to 1 if PNG library is installed])
+                    png_support=yes
+                   ],
+                   [AC_MSG_WARN(Optional png library not found)
+                    PNG_LIBS=""
+                    PNG_INCLUDES=""
+                   ],
+                   [$MATH_LIBS]),
+    [AC_MSG_WARN(png library not available - no png.h)
+     PNG_LIBS=""
+     PNG_INCLUDES=""
+    ],
+  )
+  LIBCHECK_EPILOGUE([PNG])
+])
+
+dnl === check for JPEG support ===
+
+AC_ARG_ENABLE([jpeg],
+              AS_HELP_STRING([--disable-jpeg],
+                             [Disable detection of JPEG format support
+                              @<:@default=auto@:>@]))
+AS_IF([test "x$enable_jpeg" != "xno"], [
+  CLEAR_LIBVARS([JPEG])
+  WITHLIB_OPTION([jpeg], [JPEG])
+
+  LIBCHECK_PROLOGUE([JPEG])
+  AC_CHECK_HEADER(jpeglib.h,
+    AC_CHECK_LIB(jpeg, jpeg_set_defaults,
+                 [JPEG_LIBS="$JPEG_LIBS -ljpeg"
+                  JPEG_INCLUDES="$JPEG_INCLUDES -DWEBP_HAVE_JPEG"
+                  AC_DEFINE(WEBP_HAVE_JPEG, [1],
+                            [Set to 1 if JPEG library is installed])
+                  jpeg_support=yes
+                 ],
+                 AC_MSG_WARN(Optional jpeg library not found),
+                 [$MATH_LIBS]),
+    AC_MSG_WARN(jpeg library not available - no jpeglib.h)
+  )
+  LIBCHECK_EPILOGUE([JPEG])
+])
+
+dnl === check for TIFF support ===
+
+AC_ARG_ENABLE([tiff],
+              AS_HELP_STRING([--disable-tiff],
+                             [Disable detection of TIFF format support
+                              @<:@default=auto@:>@]))
+AS_IF([test "x$enable_tiff" != "xno"], [
+  CLEAR_LIBVARS([TIFF])
+  WITHLIB_OPTION([tiff], [TIFF])
+
+  LIBCHECK_PROLOGUE([TIFF])
+  AC_CHECK_HEADER(tiffio.h,
+    AC_CHECK_LIB(tiff, TIFFGetVersion,
+                 [TIFF_LIBS="$TIFF_LIBS -ltiff"
+                  TIFF_INCLUDES="$TIFF_INCLUDES -DWEBP_HAVE_TIFF"
+                  AC_DEFINE(WEBP_HAVE_TIFF, [1],
+                            [Set to 1 if TIFF library is installed])
+                  tiff_support=yes
+                 ],
+                 AC_MSG_WARN(Optional tiff library not found),
+                 [$MATH_LIBS]),
+    AC_MSG_WARN(tiff library not available - no tiffio.h)
+  )
+  LIBCHECK_EPILOGUE([TIFF])
+])
+
+dnl === check for GIF support ===
+
+AC_ARG_ENABLE([gif], AS_HELP_STRING([--disable-gif],
+                                    [Disable detection of GIF format support
+                                     @<:@default=auto@:>@]))
+AS_IF([test "x$enable_gif" != "xno"], [
+  CLEAR_LIBVARS([GIF])
+  WITHLIB_OPTION([gif], [GIF])
+
+  LIBCHECK_PROLOGUE([GIF])
+  AC_CHECK_HEADER(gif_lib.h,
+    AC_CHECK_LIB([gif], [DGifOpenFileHandle],
+                 [GIF_LIBS="$GIF_LIBS -lgif"
+                  AC_DEFINE(WEBP_HAVE_GIF, [1],
+                            [Set to 1 if GIF library is installed])
+                  gif_support=yes
+                 ],
+                 AC_MSG_WARN(Optional gif library not found),
+                 [$MATH_LIBS]),
+    AC_MSG_WARN(gif library not available - no gif_lib.h)
+  )
+  LIBCHECK_EPILOGUE([GIF])
+
+  if test "$gif_support" = "yes" -a \
+          "$enable_libwebpdemux" = "yes"; then
+    build_anim_diff=yes
+  else
+    AC_MSG_NOTICE(
+      [Not building anim_diff. libgif and --enable-libwebpdemux are required.])
+  fi
+
+  if test "$gif_support" = "yes" -a \
+          "$enable_libwebpmux" = "yes"; then
+    build_gif2webp=yes
+  else
+    AC_MSG_NOTICE(
+      [Not building gif2webp. libgif and --enable-libwebpmux are required.])
+  fi
+])
+AM_CONDITIONAL([BUILD_ANIMDIFF], [test "${build_anim_diff}" = "yes"])
+AM_CONDITIONAL([BUILD_GIF2WEBP], [test "${build_gif2webp}" = "yes"])
+
+if test "$enable_libwebpdemux" = "yes" -a "$enable_libwebpmux" = "yes"; then
+  build_img2webp=yes
+else
+  AC_MSG_NOTICE(
+    m4_normalize([Not building img2webp.
+                  --enable-libwebpdemux & --enable-libwebpmux are required.]))
+fi
+AM_CONDITIONAL([BUILD_IMG2WEBP], [test "${build_img2webp}" = "yes"])
+
+if test "$enable_libwebpmux" = "yes"; then
+  build_webpinfo=yes
+else
+  AC_MSG_NOTICE([Not building webpinfo. --enable-libwebpdemux is required.])
+fi
+AM_CONDITIONAL([BUILD_WEBPINFO], [test "${build_webpinfo}" = "yes"])
+
+dnl === check for WIC support ===
+
+AC_ARG_ENABLE([wic],
+              AS_HELP_STRING([--disable-wic],
+                             [Disable Windows Imaging Component (WIC) detection.
+                              @<:@default=auto@:>@]),,
+              [enable_wic=yes])
+
+case $host_os in
+mingw*)
+if test "$enable_wic" = "yes"; then
+  AC_CHECK_HEADERS([wincodec.h shlwapi.h windows.h])
+  if test "$ac_cv_header_wincodec_h" = "yes"; then
+    AC_MSG_CHECKING(for Windows Imaging Component support)
+    SAVED_LIBS=$LIBS
+    LIBS="-lshlwapi -lole32 $LIBS"
+    # match include structure from [cd]webp.c
+    wic_headers="
+      #define INITGUID
+      #define CINTERFACE
+      #define COBJMACROS
+      #define _WIN32_IE 0x500
+
+      #include <shlwapi.h>
+      #include <windows.h>
+      #include <wincodec.h>
+      "
+    # test for functions from each lib and the GUID is created properly
+    wic_main="
+      int main(void) {
+        CLSID_WICImagingFactory;
+        CoInitialize(NULL);
+        SHCreateStreamOnFile(NULL, 0, NULL);
+        return 0;
+      }
+      "
+    AC_LANG_PUSH(C)
+    AC_LINK_IFELSE(
+      [AC_LANG_SOURCE([
+         $wic_headers
+         $wic_main])],
+      [wic_support=yes],
+      [wic_support=no]
+    )
+    AC_LANG_POP
+
+    test "$wic_support" = "yes" || LIBS=$SAVED_LIBS
+    AC_MSG_RESULT(${wic_support-no})
+  fi
+fi
+esac
+
+dnl === If --enable-swap-16bit-csp is defined, add -DWEBP_SWAP_16BIT_CSP=1
+
+USE_SWAP_16BIT_CSP=""
+AC_MSG_CHECKING(if --enable-swap-16bit-csp option is specified)
+AC_ARG_ENABLE([swap-16bit-csp],
+              AS_HELP_STRING([--enable-swap-16bit-csp],
+                             [Enable byte swap for 16 bit colorspaces]))
+if test "$enable_swap_16bit_csp" = "yes"; then
+  USE_SWAP_16BIT_CSP="-DWEBP_SWAP_16BIT_CSP=1"
+fi
+AC_MSG_RESULT(${enable_swap_16bit_csp-no})
+AC_SUBST(USE_SWAP_16BIT_CSP)
+
+dnl === If --disable-near-lossless is defined, add -DWEBP_NEAR_LOSSLESS=0
+
+AC_DEFINE(WEBP_NEAR_LOSSLESS, [1], [Enable near lossless encoding])
+AC_MSG_CHECKING(if --disable-near-lossless option is specified)
+AC_ARG_ENABLE([near_lossless],
+              AS_HELP_STRING([--disable-near-lossless],
+                             [Disable near lossless encoding]),
+              [], [enable_near_lossless=yes])
+if test "$enable_near_lossless" = "no"; then
+  AC_DEFINE(WEBP_NEAR_LOSSLESS, [0], [Enable near lossless encoding])
+  AC_MSG_RESULT([yes])
+else
+  AC_MSG_RESULT([no])
+fi
+
+dnl =========================
+
+dnl Add an empty webp_libname_prefix variable for use in *.pc.in.
+AC_SUBST([webp_libname_prefix])
+AC_CONFIG_MACRO_DIR([m4])
+AC_CONFIG_HEADERS([src/webp/config.h])
+AC_CONFIG_FILES([Makefile src/Makefile man/Makefile \
+                 examples/Makefile extras/Makefile imageio/Makefile \
+                 sharpyuv/Makefile sharpyuv/libsharpyuv.pc \
+                 src/dec/Makefile src/enc/Makefile src/dsp/Makefile \
+                 src/demux/Makefile src/mux/Makefile \
+                 src/utils/Makefile \
+                 src/libwebp.pc src/libwebpdecoder.pc \
+                 src/demux/libwebpdemux.pc src/mux/libwebpmux.pc])
+
+
+AC_OUTPUT
+
+AC_MSG_NOTICE([
+WebP Configuration Summary
+--------------------------
+
+Shared libraries: ${enable_shared}
+Static libraries: ${enable_static}
+Threading support: ${enable_threading-no}
+libwebp: yes
+libwebpdecoder: ${enable_libwebpdecoder-no}
+libwebpdemux: ${enable_libwebpdemux-no}
+libwebpmux: ${enable_libwebpmux-no}
+libwebpextras: ${enable_libwebpextras-no}
+
+Tools:
+cwebp : ${enable_libwebpdemux-no}
+  Input format support
+  ====================
+  JPEG : ${jpeg_support-no}
+  PNG  : ${png_support-no}
+  TIFF : ${tiff_support-no}
+  WIC  : ${wic_support-no}
+dwebp : ${enable_libwebpdemux-no}
+  Output format support
+  =====================
+  PNG  : ${png_support-no}
+  WIC  : ${wic_support-no}
+GIF support : ${gif_support-no}
+anim_diff   : ${build_anim_diff-no}
+gif2webp    : ${build_gif2webp-no}
+img2webp    : ${build_img2webp-no}
+webpmux     : ${enable_libwebpmux-no}
+vwebp       : ${build_vwebp-no}
+webpinfo    : ${build_webpinfo-no}
+SDL support : ${sdl_support-no}
+vwebp_sdl   : ${build_vwebp_sdl-no}
+])
--- a/external/libwebp/libwebp/doc/TODO
+++ b/external/libwebp/libwebp/doc/TODO
@@ -0,0 +1,13 @@
+<louquillio@google.com>, 20111004
+
+* Determine that normative RFC 2119 terms (MUST, SHOULD, MAY, etc.) are
+  truly intended in all cases where capitalized.
+
+* Several passages could be made clearer.
+
+  * Overall edit for scope.  Portions are phrased as an introduction to
+    the 0.1.3 RIFF container additions, rather than a holistic guide to
+    WebP.
+
+  * To wit, suggest s/[spec|specification]/guide/g .  "Spec" can imply a
+    standards track; in any case it's too formal for a work in progress.
--- a/external/libwebp/libwebp/doc/api.md
+++ b/external/libwebp/libwebp/doc/api.md
@@ -0,0 +1,385 @@
+# WebP APIs
+
+## Encoding API
+
+The main encoding functions are available in the header src/webp/encode.h
+
+The ready-to-use ones are:
+
+```c
+size_t WebPEncodeRGB(const uint8_t* rgb, int width, int height, int stride,
+                     float quality_factor, uint8_t** output);
+size_t WebPEncodeBGR(const uint8_t* bgr, int width, int height, int stride,
+                     float quality_factor, uint8_t** output);
+size_t WebPEncodeRGBA(const uint8_t* rgba, int width, int height, int stride,
+                      float quality_factor, uint8_t** output);
+size_t WebPEncodeBGRA(const uint8_t* bgra, int width, int height, int stride,
+                      float quality_factor, uint8_t** output);
+```
+
+They will convert raw RGB samples to a WebP data. The only control supplied is
+the quality factor.
+
+There are some variants for using the lossless format:
+
+```c
+size_t WebPEncodeLosslessRGB(const uint8_t* rgb, int width, int height,
+                             int stride, uint8_t** output);
+size_t WebPEncodeLosslessBGR(const uint8_t* bgr, int width, int height,
+                             int stride, uint8_t** output);
+size_t WebPEncodeLosslessRGBA(const uint8_t* rgba, int width, int height,
+                              int stride, uint8_t** output);
+size_t WebPEncodeLosslessBGRA(const uint8_t* bgra, int width, int height,
+                              int stride, uint8_t** output);
+```
+
+Of course in this case, no quality factor is needed since the compression occurs
+without loss of the input values, at the expense of larger output sizes.
+
+### Advanced encoding API
+
+A more advanced API is based on the WebPConfig and WebPPicture structures.
+
+WebPConfig contains the encoding settings and is not tied to a particular
+picture. WebPPicture contains input data, on which some WebPConfig will be used
+for compression. The encoding flow looks like:
+
+```c
+#include <webp/encode.h>
+
+// Setup a config, starting form a preset and tuning some additional
+// parameters
+WebPConfig config;
+if (!WebPConfigPreset(&config, WEBP_PRESET_PHOTO, quality_factor)) {
+  return 0;   // version error
+}
+// ... additional tuning
+config.sns_strength = 90;
+config.filter_sharpness = 6;
+config_error = WebPValidateConfig(&config);  // not mandatory, but useful
+
+// Setup the input data
+WebPPicture pic;
+if (!WebPPictureInit(&pic)) {
+  return 0;  // version error
+}
+pic.width = width;
+pic.height = height;
+// allocated picture of dimension width x height
+if (!WebPPictureAlloc(&pic)) {
+  return 0;   // memory error
+}
+// at this point, 'pic' has been initialized as a container,
+// and can receive the Y/U/V samples.
+// Alternatively, one could use ready-made import functions like
+// WebPPictureImportRGB(), which will take care of memory allocation.
+// In any case, past this point, one will have to call
+// WebPPictureFree(&pic) to reclaim memory.
+
+// Set up a byte-output write method. WebPMemoryWriter, for instance.
+WebPMemoryWriter wrt;
+WebPMemoryWriterInit(&wrt);     // initialize 'wrt'
+
+pic.writer = MyFileWriter;
+pic.custom_ptr = my_opaque_structure_to_make_MyFileWriter_work;
+
+// Compress!
+int ok = WebPEncode(&config, &pic);   // ok = 0 => error occurred!
+WebPPictureFree(&pic);  // must be called independently of the 'ok' result.
+
+// output data should have been handled by the writer at that point.
+// -> compressed data is the memory buffer described by wrt.mem / wrt.size
+
+// deallocate the memory used by compressed data
+WebPMemoryWriterClear(&wrt);
+```
+
+## Decoding API
+
+This is mainly just one function to call:
+
+```c
+#include "webp/decode.h"
+uint8_t* WebPDecodeRGB(const uint8_t* data, size_t data_size,
+                       int* width, int* height);
+```
+
+Please have a look at the file src/webp/decode.h for the details. There are
+variants for decoding in BGR/RGBA/ARGB/BGRA order, along with decoding to raw
+Y'CbCr samples. One can also decode the image directly into a pre-allocated
+buffer.
+
+To detect a WebP file and gather the picture's dimensions, the function:
+
+```c
+int WebPGetInfo(const uint8_t* data, size_t data_size,
+                int* width, int* height);
+```
+
+is supplied. No decoding is involved when using it.
+
+### Incremental decoding API
+
+In the case when data is being progressively transmitted, pictures can still be
+incrementally decoded using a slightly more complicated API. Decoder state is
+stored into an instance of the WebPIDecoder object. This object can be created
+with the purpose of decoding either RGB or Y'CbCr samples. For instance:
+
+```c
+WebPDecBuffer buffer;
+WebPInitDecBuffer(&buffer);
+buffer.colorspace = MODE_BGR;
+...
+WebPIDecoder* idec = WebPINewDecoder(&buffer);
+```
+
+As data is made progressively available, this incremental-decoder object can be
+used to decode the picture further. There are two (mutually exclusive) ways to
+pass freshly arrived data:
+
+either by appending the fresh bytes:
+
+```c
+WebPIAppend(idec, fresh_data, size_of_fresh_data);
+```
+
+or by just mentioning the new size of the transmitted data:
+
+```c
+WebPIUpdate(idec, buffer, size_of_transmitted_buffer);
+```
+
+Note that 'buffer' can be modified between each call to WebPIUpdate, in
+particular when the buffer is resized to accommodate larger data.
+
+These functions will return the decoding status: either VP8_STATUS_SUSPENDED if
+decoding is not finished yet or VP8_STATUS_OK when decoding is done. Any other
+status is an error condition.
+
+The 'idec' object must always be released (even upon an error condition) by
+calling: WebPDelete(idec).
+
+To retrieve partially decoded picture samples, one must use the corresponding
+method: WebPIDecGetRGB or WebPIDecGetYUVA. It will return the last displayable
+pixel row.
+
+Lastly, note that decoding can also be performed into a pre-allocated pixel
+buffer. This buffer must be passed when creating a WebPIDecoder, calling
+WebPINewRGB() or WebPINewYUVA().
+
+Please have a look at the src/webp/decode.h header for further details.
+
+### Advanced Decoding API
+
+WebP decoding supports an advanced API which provides on-the-fly cropping and
+rescaling, something of great usefulness on memory-constrained environments like
+mobile phones. Basically, the memory usage will scale with the output's size,
+not the input's, when one only needs a quick preview or a zoomed in portion of
+an otherwise too-large picture. Some CPU can be saved too, incidentally.
+
+```c
+// A) Init a configuration object
+WebPDecoderConfig config;
+CHECK(WebPInitDecoderConfig(&config));
+
+// B) optional: retrieve the bitstream's features.
+CHECK(WebPGetFeatures(data, data_size, &config.input) == VP8_STATUS_OK);
+
+// C) Adjust 'config' options, if needed
+config.options.no_fancy_upsampling = 1;
+config.options.use_scaling = 1;
+config.options.scaled_width = scaledWidth();
+config.options.scaled_height = scaledHeight();
+// etc.
+
+// D) Specify 'config' output options for specifying output colorspace.
+// Optionally the external image decode buffer can also be specified.
+config.output.colorspace = MODE_BGRA;
+// Optionally, the config.output can be pointed to an external buffer as
+// well for decoding the image. This externally supplied memory buffer
+// should be big enough to store the decoded picture.
+config.output.u.RGBA.rgba = (uint8_t*) memory_buffer;
+config.output.u.RGBA.stride = scanline_stride;
+config.output.u.RGBA.size = total_size_of_the_memory_buffer;
+config.output.is_external_memory = 1;
+
+// E) Decode the WebP image. There are two variants w.r.t decoding image.
+// The first one (E.1) decodes the full image and the second one (E.2) is
+// used to incrementally decode the image using small input buffers.
+// Any one of these steps can be used to decode the WebP image.
+
+// E.1) Decode full image.
+CHECK(WebPDecode(data, data_size, &config) == VP8_STATUS_OK);
+
+// E.2) Decode image incrementally.
+WebPIDecoder* const idec = WebPIDecode(NULL, NULL, &config);
+CHECK(idec != NULL);
+while (bytes_remaining > 0) {
+  VP8StatusCode status = WebPIAppend(idec, input, bytes_read);
+  if (status == VP8_STATUS_OK || status == VP8_STATUS_SUSPENDED) {
+    bytes_remaining -= bytes_read;
+  } else {
+    break;
+  }
+}
+WebPIDelete(idec);
+
+// F) Decoded image is now in config.output (and config.output.u.RGBA).
+// It can be saved, displayed or otherwise processed.
+
+// G) Reclaim memory allocated in config's object. It's safe to call
+// this function even if the memory is external and wasn't allocated
+// by WebPDecode().
+WebPFreeDecBuffer(&config.output);
+```
+
+## WebP Mux
+
+WebPMux is a set of two libraries 'Mux' and 'Demux' for creation, extraction and
+manipulation of an extended format WebP file, which can have features like color
+profile, metadata and animation. Reference command-line tools `webpmux` and
+`vwebp` as well as the WebP container specification
+'doc/webp-container-spec.txt' are also provided in this package, see the
+[tools documentation](tools.md).
+
+### Mux API
+
+The Mux API contains methods for adding data to and reading data from WebP
+files. This API currently supports XMP/EXIF metadata, ICC profile and animation.
+Other features may be added in subsequent releases.
+
+Example#1 (pseudo code): Creating a WebPMux object with image data, color
+profile and XMP metadata.
+
+```c
+int copy_data = 0;
+WebPMux* mux = WebPMuxNew();
+// ... (Prepare image data).
+WebPMuxSetImage(mux, &image, copy_data);
+// ... (Prepare ICC profile data).
+WebPMuxSetChunk(mux, "ICCP", &icc_profile, copy_data);
+// ... (Prepare XMP metadata).
+WebPMuxSetChunk(mux, "XMP ", &xmp, copy_data);
+// Get data from mux in WebP RIFF format.
+WebPMuxAssemble(mux, &output_data);
+WebPMuxDelete(mux);
+// ... (Consume output_data; e.g. write output_data.bytes to file).
+WebPDataClear(&output_data);
+```
+
+Example#2 (pseudo code): Get image and color profile data from a WebP file.
+
+```c
+int copy_data = 0;
+// ... (Read data from file).
+WebPMux* mux = WebPMuxCreate(&data, copy_data);
+WebPMuxGetFrame(mux, 1, &image);
+// ... (Consume image; e.g. call WebPDecode() to decode the data).
+WebPMuxGetChunk(mux, "ICCP", &icc_profile);
+// ... (Consume icc_profile).
+WebPMuxDelete(mux);
+free(data);
+```
+
+For a detailed Mux API reference, please refer to the header file
+(src/webp/mux.h).
+
+### Demux API
+
+The Demux API enables extraction of images and extended format data from WebP
+files. This API currently supports reading of XMP/EXIF metadata, ICC profile and
+animated images. Other features may be added in subsequent releases.
+
+Code example: Demuxing WebP data to extract all the frames, ICC profile and
+EXIF/XMP metadata.
+
+```c
+WebPDemuxer* demux = WebPDemux(&webp_data);
+uint32_t width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH);
+uint32_t height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT);
+// ... (Get information about the features present in the WebP file).
+uint32_t flags = WebPDemuxGetI(demux, WEBP_FF_FORMAT_FLAGS);
+
+// ... (Iterate over all frames).
+WebPIterator iter;
+if (WebPDemuxGetFrame(demux, 1, &iter)) {
+  do {
+    // ... (Consume 'iter'; e.g. Decode 'iter.fragment' with WebPDecode(),
+    // ... and get other frame properties like width, height, offsets etc.
+    // ... see 'struct WebPIterator' below for more info).
+  } while (WebPDemuxNextFrame(&iter));
+  WebPDemuxReleaseIterator(&iter);
+}
+
+// ... (Extract metadata).
+WebPChunkIterator chunk_iter;
+if (flags & ICCP_FLAG) WebPDemuxGetChunk(demux, "ICCP", 1, &chunk_iter);
+// ... (Consume the ICC profile in 'chunk_iter.chunk').
+WebPDemuxReleaseChunkIterator(&chunk_iter);
+if (flags & EXIF_FLAG) WebPDemuxGetChunk(demux, "EXIF", 1, &chunk_iter);
+// ... (Consume the EXIF metadata in 'chunk_iter.chunk').
+WebPDemuxReleaseChunkIterator(&chunk_iter);
+if (flags & XMP_FLAG) WebPDemuxGetChunk(demux, "XMP ", 1, &chunk_iter);
+// ... (Consume the XMP metadata in 'chunk_iter.chunk').
+WebPDemuxReleaseChunkIterator(&chunk_iter);
+WebPDemuxDelete(demux);
+```
+
+For a detailed Demux API reference, please refer to the header file
+(src/webp/demux.h).
+
+## AnimEncoder API
+
+The AnimEncoder API can be used to create animated WebP images.
+
+Code example:
+
+```c
+WebPAnimEncoderOptions enc_options;
+WebPAnimEncoderOptionsInit(&enc_options);
+// ... (Tune 'enc_options' as needed).
+WebPAnimEncoder* enc = WebPAnimEncoderNew(width, height, &enc_options);
+while(<there are more frames>) {
+  WebPConfig config;
+  WebPConfigInit(&config);
+  // ... (Tune 'config' as needed).
+  WebPAnimEncoderAdd(enc, frame, duration, &config);
+}
+WebPAnimEncoderAssemble(enc, webp_data);
+WebPAnimEncoderDelete(enc);
+// ... (Write the 'webp_data' to a file, or re-mux it further).
+```
+
+For a detailed AnimEncoder API reference, please refer to the header file
+(src/webp/mux.h).
+
+## AnimDecoder API
+
+This AnimDecoder API allows decoding (possibly) animated WebP images.
+
+Code Example:
+
+```c
+WebPAnimDecoderOptions dec_options;
+WebPAnimDecoderOptionsInit(&dec_options);
+// Tune 'dec_options' as needed.
+WebPAnimDecoder* dec = WebPAnimDecoderNew(webp_data, &dec_options);
+WebPAnimInfo anim_info;
+WebPAnimDecoderGetInfo(dec, &anim_info);
+for (uint32_t i = 0; i < anim_info.loop_count; ++i) {
+  while (WebPAnimDecoderHasMoreFrames(dec)) {
+    uint8_t* buf;
+    int timestamp;
+    WebPAnimDecoderGetNext(dec, &buf, &timestamp);
+    // ... (Render 'buf' based on 'timestamp').
+    // ... (Do NOT free 'buf', as it is owned by 'dec').
+  }
+  WebPAnimDecoderReset(dec);
+}
+const WebPDemuxer* demuxer = WebPAnimDecoderGetDemuxer(dec);
+// ... (Do something using 'demuxer'; e.g. get EXIF/XMP/ICC data).
+WebPAnimDecoderDelete(dec);
+```
+
+For a detailed AnimDecoder API reference, please refer to the header file
+(src/webp/demux.h).
--- a/external/libwebp/libwebp/doc/building.md
+++ b/external/libwebp/libwebp/doc/building.md
@@ -0,0 +1,213 @@
+# Building
+
+## Windows build
+
+By running:
+
+```batch
+nmake /f Makefile.vc CFG=release-static RTLIBCFG=static OBJDIR=output
+```
+
+the directory `output\release-static\(x64|x86)\bin` will contain the tools
+cwebp.exe and dwebp.exe. The directory `output\release-static\(x64|x86)\lib`
+will contain the libwebp static library. The target architecture (x86/x64) is
+detected by Makefile.vc from the Visual Studio compiler (cl.exe) available in
+the system path.
+
+## Unix build using makefile.unix
+
+On platforms with GNU tools installed (gcc and make), running
+
+```shell
+make -f makefile.unix
+```
+
+will build the binaries examples/cwebp and examples/dwebp, along with the static
+library src/libwebp.a. No system-wide installation is supplied, as this is a
+simple alternative to the full installation system based on the autoconf tools
+(see below). Please refer to makefile.unix for additional details and
+customizations.
+
+## Using autoconf tools
+
+Prerequisites: a compiler (e.g., gcc), make, autoconf, automake, libtool.
+
+On a Debian-like system the following should install everything you need for a
+minimal build:
+
+```shell
+$ sudo apt-get install gcc make autoconf automake libtool
+```
+
+When building from git sources, you will need to run autogen.sh to generate the
+configure script.
+
+```shell
+./configure
+make
+make install
+```
+
+should be all you need to have the following files
+
+```
+/usr/local/include/webp/decode.h
+/usr/local/include/webp/encode.h
+/usr/local/include/webp/types.h
+/usr/local/lib/libwebp.*
+/usr/local/bin/cwebp
+/usr/local/bin/dwebp
+```
+
+installed.
+
+Note: A decode-only library, libwebpdecoder, is available using the
+`--enable-libwebpdecoder` flag. The encode library is built separately and can
+be installed independently using a minor modification in the corresponding
+Makefile.am configure files (see comments there). See `./configure --help` for
+more options.
+
+## Building for MIPS Linux
+
+MIPS Linux toolchain stable available releases can be found at:
+https://community.imgtec.com/developers/mips/tools/codescape-mips-sdk/available-releases/
+
+```shell
+# Add toolchain to PATH
+export PATH=$PATH:/path/to/toolchain/bin
+
+# 32-bit build for mips32r5 (p5600)
+HOST=mips-mti-linux-gnu
+MIPS_CFLAGS="-O3 -mips32r5 -mabi=32 -mtune=p5600 -mmsa -mfp64 \
+  -msched-weight -mload-store-pairs -fPIE"
+MIPS_LDFLAGS="-mips32r5 -mabi=32 -mmsa -mfp64 -pie"
+
+# 64-bit build for mips64r6 (i6400)
+HOST=mips-img-linux-gnu
+MIPS_CFLAGS="-O3 -mips64r6 -mabi=64 -mtune=i6400 -mmsa -mfp64 \
+  -msched-weight -mload-store-pairs -fPIE"
+MIPS_LDFLAGS="-mips64r6 -mabi=64 -mmsa -mfp64 -pie"
+
+./configure --host=${HOST} --build=`config.guess` \
+  CC="${HOST}-gcc -EL" \
+  CFLAGS="$MIPS_CFLAGS" \
+  LDFLAGS="$MIPS_LDFLAGS"
+make
+make install
+```
+
+## CMake
+
+With CMake, you can compile libwebp, cwebp, dwebp, gif2webp, img2webp, webpinfo
+and the JS bindings.
+
+Prerequisites: a compiler (e.g., gcc with autotools) and CMake.
+
+On a Debian-like system the following should install everything you need for a
+minimal build:
+
+```shell
+$ sudo apt-get install build-essential cmake
+```
+
+When building from git sources, you will need to run cmake to generate the
+makefiles.
+
+```shell
+mkdir build && cd build && cmake ../
+make
+make install
+```
+
+If you also want any of the executables, you will need to enable them through
+CMake, e.g.:
+
+```shell
+cmake -DWEBP_BUILD_CWEBP=ON -DWEBP_BUILD_DWEBP=ON ../
+```
+
+or through your favorite interface (like ccmake or cmake-qt-gui).
+
+Use option `-DWEBP_UNICODE=ON` for Unicode support on Windows (with chcp 65001).
+
+Finally, once installed, you can also use WebP in your CMake project by doing:
+
+```cmake
+find_package(WebP)
+```
+
+which will define the CMake variables WebP_INCLUDE_DIRS and WebP_LIBRARIES.
+
+## Gradle
+
+The support for Gradle is minimal: it only helps you compile libwebp, cwebp and
+dwebp and webpmux_example.
+
+Prerequisites: a compiler (e.g., gcc with autotools) and gradle.
+
+On a Debian-like system the following should install everything you need for a
+minimal build:
+
+```shell
+$ sudo apt-get install build-essential gradle
+```
+
+When building from git sources, you will need to run the Gradle wrapper with the
+appropriate target, e.g. :
+
+```shell
+./gradlew buildAllExecutables
+```
+
+## SWIG bindings
+
+To generate language bindings from swig/libwebp.swig at least swig-1.3
+(http://www.swig.org) is required.
+
+Currently the following functions are mapped:
+
+Decode:
+
+```
+WebPGetDecoderVersion
+WebPGetInfo
+WebPDecodeRGBA
+WebPDecodeARGB
+WebPDecodeBGRA
+WebPDecodeBGR
+WebPDecodeRGB
+```
+
+Encode:
+
+```
+WebPGetEncoderVersion
+WebPEncodeRGBA
+WebPEncodeBGRA
+WebPEncodeRGB
+WebPEncodeBGR
+WebPEncodeLosslessRGBA
+WebPEncodeLosslessBGRA
+WebPEncodeLosslessRGB
+WebPEncodeLosslessBGR
+```
+
+See also the [swig documentation](../swig/README.md) for more detailed build
+instructions and usage examples.
+
+### Java bindings
+
+To build the swig-generated JNI wrapper code at least JDK-1.5 (or equivalent) is
+necessary for enum support. The output is intended to be a shared object / DLL
+that can be loaded via `System.loadLibrary("webp_jni")`.
+
+### Python bindings
+
+To build the swig-generated Python extension code at least Python 2.6 is
+required. Python < 2.6 may build with some minor changes to libwebp.swig or the
+generated code, but is untested.
+
+## Javascript decoder
+
+Libwebp can be compiled into a JavaScript decoder using Emscripten and CMake.
+See the [corresponding documentation](../README.md)
--- a/external/libwebp/libwebp/doc/specs_generation.md
+++ b/external/libwebp/libwebp/doc/specs_generation.md
@@ -0,0 +1,26 @@
+# Generate libwebp Container Spec Docs from Text Source
+
+HTML generation requires [kramdown](https://kramdown.gettalong.org/), easily
+installed as a [rubygem](https://rubygems.org/). Rubygems installation should
+satisfy dependencies automatically.
+
+HTML generation can then be done from the project root:
+
+```shell
+$ kramdown doc/webp-container-spec.txt --template doc/template.html > \
+  doc/output/webp-container-spec.html
+```
+
+kramdown can optionally syntax highlight code blocks, using
+[CodeRay](https://github.com/rubychan/coderay), a dependency of kramdown that
+rubygems will install automatically. The following will apply inline CSS
+styling; an external stylesheet is not needed.
+
+```shell
+$ kramdown doc/webp-lossless-bitstream-spec.txt --template \
+  doc/template.html --coderay-css style --coderay-line-numbers ' ' \
+  --coderay-default-lang c > \
+  doc/output/webp-lossless-bitstream-spec.html
+```
+
+Optimally, use kramdown 0.13.7 or newer if syntax highlighting desired.
--- a/external/libwebp/libwebp/doc/template.html
+++ b/external/libwebp/libwebp/doc/template.html
@@ -0,0 +1,94 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <title>WebP Container Specification</title>
+  <meta name="generator" content="kramdown <%= ::Kramdown::VERSION %>" />
+  <style type="text/css">
+  body {
+    color: #000;
+    background-color: #fff;
+    margin: 10%;
+    font-family: "Liberation Sans", "DejaVu Sans", "Bitstream Vera Sans", Arial, sans-serif;
+    line-height: 1.4;
+  }
+  h2 {
+    border-bottom: 1px solid #ccc;
+    padding-bottom: 0;
+  }
+  table {
+    border-collapse: collapse;
+  }
+  th, td {
+    border: 1px solid #999;
+    padding: .5em .7em;;
+  }
+  th {
+    color: #fff;
+    background-color: #000;
+  }
+  td {
+  }
+  hr {
+  }
+  code {
+    color: #000;
+    background-color: #f7f7f7;
+    padding: 0 3px;
+    font-family: "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", Consolata, monospace;
+  }
+  pre {
+    background-color: #f7f7f7;
+    padding: 1em;
+    border: 1px solid #ccc;
+    width: 42em;
+    overflow: auto;
+    font-family: "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", Consolata, monospace;
+  }
+  pre code {
+    background-color: #f7f7f7;
+    padding: 0; /* Only want padding on inline code, not blocks */
+  }
+  pre.terminal {
+    color: #fff;
+    background-color: #000;
+    border: 1px solid #ccc;
+    max-height: 30em;
+  }
+  pre.terminal code {
+    color: #fff;
+    background-color: #000;
+    font-size: smaller;
+  }
+  #markdown-toc ul {
+    list-style-type: disc;
+  }
+  ul#markdown-toc {
+    margin-top: -1em;
+    visibility: hidden;
+    -webkit-padding-start: 0;
+  }
+  ul#markdown-toc ul {
+    visibility: visible;
+  }
+  ul#markdown-toc ul ul{
+    visibility: visible;
+  }
+  ul#markdown-toc + hr {
+    margin-bottom: 4em;
+  }
+  ol ol { /* Format nested ordered lists */
+    list-style-type: lower-alpha;
+  }
+  dt {
+    font-style: italic;
+    font-weight: bold;
+  }
+  .caption {
+  }
+  </style>
+</head>
+<body>
+<%= @body %>
+</body>
+</html>
--- a/external/libwebp/libwebp/doc/tools.md
+++ b/external/libwebp/libwebp/doc/tools.md
@@ -0,0 +1,516 @@
+# WebP tools
+
+## Encoding tool
+
+The examples/ directory contains tools for encoding (cwebp) and decoding (dwebp)
+images.
+
+The easiest use should look like:
+
+```shell
+cwebp input.png -q 80 -o output.webp
+```
+
+which will convert the input file to a WebP file using a quality factor of 80 on
+a 0->100 scale (0 being the lowest quality, 100 being the best. Default value is
+75).
+
+You might want to try the `-lossless` flag too, which will compress the source
+(in RGBA format) without any loss. The `-q` quality parameter will in this case
+control the amount of processing time spent trying to make the output file as
+small as possible.
+
+A longer list of options is available using the `-longhelp` command line flag:
+
+```shell
+> cwebp -longhelp
+Usage:
+ cwebp [-preset <...>] [options] in_file [-o out_file]
+```
+
+If input size (-s) for an image is not specified, it is assumed to be a PNG,
+JPEG, TIFF or WebP file. Note: Animated PNG and WebP files are not supported.
+
+Options:
+
+```
+-h / -help ............. short help
+-H / -longhelp ......... long help
+-q <float> ............. quality factor (0:small..100:big), default=75
+-alpha_q <int> ......... transparency-compression quality (0..100),
+                         default=100
+-preset <string> ....... preset setting, one of:
+                          default, photo, picture,
+                          drawing, icon, text
+   -preset must come first, as it overwrites other parameters
+-z <int> ............... activates lossless preset with given
+                         level in [0:fast, ..., 9:slowest]
+
+-m <int> ............... compression method (0=fast, 6=slowest), default=4
+-segments <int> ........ number of segments to use (1..4), default=4
+-size <int> ............ target size (in bytes)
+-psnr <float> .......... target PSNR (in dB. typically: 42)
+
+-s <int> <int> ......... input size (width x height) for YUV
+-sns <int> ............. spatial noise shaping (0:off, 100:max), default=50
+-f <int> ............... filter strength (0=off..100), default=60
+-sharpness <int> ....... filter sharpness (0:most .. 7:least sharp), default=0
+-strong ................ use strong filter instead of simple (default)
+-nostrong .............. use simple filter instead of strong
+-sharp_yuv ............. use sharper (and slower) RGB->YUV conversion
+-partition_limit <int> . limit quality to fit the 512k limit on
+                         the first partition (0=no degradation ... 100=full)
+-pass <int> ............ analysis pass number (1..10)
+-qrange <min> <max> .... specifies the permissible quality range
+                         (default: 0 100)
+-crop <x> <y> <w> <h> .. crop picture with the given rectangle
+-resize <w> <h> ........ resize picture (*after* any cropping)
+-mt .................... use multi-threading if available
+-low_memory ............ reduce memory usage (slower encoding)
+-map <int> ............. print map of extra info
+-print_psnr ............ prints averaged PSNR distortion
+-print_ssim ............ prints averaged SSIM distortion
+-print_lsim ............ prints local-similarity distortion
+-d <file.pgm> .......... dump the compressed output (PGM file)
+-alpha_method <int> .... transparency-compression method (0..1), default=1
+-alpha_filter <string> . predictive filtering for alpha plane,
+                         one of: none, fast (default) or best
+-exact ................. preserve RGB values in transparent area, default=off
+-blend_alpha <hex> ..... blend colors against background color
+                         expressed as RGB values written in
+                         hexadecimal, e.g. 0xc0e0d0 for red=0xc0
+                         green=0xe0 and blue=0xd0
+-noalpha ............... discard any transparency information
+-lossless .............. encode image losslessly, default=off
+-near_lossless <int> ... use near-lossless image preprocessing
+                         (0..100=off), default=100
+-hint <string> ......... specify image characteristics hint,
+                         one of: photo, picture or graph
+
+-metadata <string> ..... comma separated list of metadata to
+                         copy from the input to the output if present.
+                         Valid values: all, none (default), exif, icc, xmp
+
+-short ................. condense printed message
+-quiet ................. don't print anything
+-version ............... print version number and exit
+-noasm ................. disable all assembly optimizations
+-v ..................... verbose, e.g. print encoding/decoding times
+-progress .............. report encoding progress
+```
+
+Experimental Options:
+
+```
+-jpeg_like ............. roughly match expected JPEG size
+-af .................... auto-adjust filter strength
+-pre <int> ............. pre-processing filter
+```
+
+The main options you might want to try in order to further tune the visual
+quality are:
+
+-preset -sns -f -m
+
+Namely:
+
+*   `preset` will set up a default encoding configuration targeting a particular
+    type of input. It should appear first in the list of options, so that
+    subsequent options can take effect on top of this preset. Default value is
+    'default'.
+*   `sns` will progressively turn on (when going from 0 to 100) some additional
+    visual optimizations (like: segmentation map re-enforcement). This option
+    will balance the bit allocation differently. It tries to take bits from the
+    "easy" parts of the picture and use them in the "difficult" ones instead.
+    Usually, raising the sns value (at fixed -q value) leads to larger files,
+    but with better quality. Typical value is around '75'.
+*   `f` option directly links to the filtering strength used by the codec's
+    in-loop processing. The higher the value, the smoother the highly-compressed
+    area will look. This is particularly useful when aiming at very small files.
+    Typical values are around 20-30. Note that using the option
+    -strong/-nostrong will change the type of filtering. Use "-f 0" to turn
+    filtering off.
+*   `m` controls the trade-off between encoding speed and quality. Default is 4.
+    You can try -m 5 or -m 6 to explore more (time-consuming) encoding
+    possibilities. A lower value will result in faster encoding at the expense
+    of quality.
+
+## Decoding tool
+
+There is a decoding sample in examples/dwebp.c which will take a .webp file and
+decode it to a PNG image file (amongst other formats). This is simply to
+demonstrate the use of the API. You can verify the file test.webp decodes to
+exactly the same as test_ref.ppm by using:
+
+```shell
+cd examples
+./dwebp test.webp -ppm -o test.ppm
+diff test.ppm test_ref.ppm
+```
+
+The full list of options is available using -h:
+
+```shell
+> dwebp -h
+Usage: dwebp in_file [options] [-o out_file]
+```
+
+Decodes the WebP image file to PNG format [Default]. Note: Animated WebP files
+are not supported.
+
+Use following options to convert into alternate image formats:
+
+```
+-pam ......... save the raw RGBA samples as a color PAM
+-ppm ......... save the raw RGB samples as a color PPM
+-bmp ......... save as uncompressed BMP format
+-tiff ........ save as uncompressed TIFF format
+-pgm ......... save the raw YUV samples as a grayscale PGM
+               file with IMC4 layout
+-yuv ......... save the raw YUV samples in flat layout
+```
+
+Other options are:
+
+```
+-version ..... print version number and exit
+-nofancy ..... don't use the fancy YUV420 upscaler
+-nofilter .... disable in-loop filtering
+-nodither .... disable dithering
+-dither <d> .. dithering strength (in 0..100)
+-alpha_dither  use alpha-plane dithering if needed
+-mt .......... use multi-threading
+-crop <x> <y> <w> <h> ... crop output with the given rectangle
+-resize <w> <h> ......... resize output (*after* any cropping)
+-flip ........ flip the output vertically
+-alpha ....... only save the alpha plane
+-incremental . use incremental decoding (useful for tests)
+-h ........... this help message
+-v ........... verbose (e.g. print encoding/decoding times)
+-quiet ....... quiet mode, don't print anything
+-noasm ....... disable all assembly optimizations
+```
+
+## WebP file analysis tool
+
+`webpinfo` can be used to print out the chunk level structure and bitstream
+header information of WebP files. It can also check if the files are of valid
+WebP format.
+
+Usage:
+
+```shell
+webpinfo [options] in_files
+```
+
+Note: there could be multiple input files; options must come before input files.
+
+Options:
+
+```
+-version ........... Print version number and exit.
+-quiet ............. Do not show chunk parsing information.
+-diag .............. Show parsing error diagnosis.
+-summary ........... Show chunk stats summary.
+-bitstream_info .... Parse bitstream header.
+```
+
+## Visualization tool
+
+There's a little self-serve visualization tool called 'vwebp' under the
+examples/ directory. It uses OpenGL to open a simple drawing window and show a
+decoded WebP file. It's not yet integrated in the automake build system, but you
+can try to manually compile it using the recommendations below.
+
+Usage:
+
+```shell
+vwebp in_file [options]
+```
+
+Decodes the WebP image file and visualize it using OpenGL
+
+Options are:
+
+```
+-version ..... print version number and exit
+-noicc ....... don't use the icc profile if present
+-nofancy ..... don't use the fancy YUV420 upscaler
+-nofilter .... disable in-loop filtering
+-dither <int>  dithering strength (0..100), default=50
+-noalphadither disable alpha plane dithering
+-usebgcolor .. display background color
+-mt .......... use multi-threading
+-info ........ print info
+-h ........... this help message
+```
+
+Keyboard shortcuts:
+
+```
+'c' ................ toggle use of color profile
+'b' ................ toggle background color display
+'i' ................ overlay file information
+'d' ................ disable blending & disposal (debug)
+'q' / 'Q' / ESC .... quit
+```
+
+### Building
+
+Prerequisites:
+
+1.  OpenGL & OpenGL Utility Toolkit (GLUT)
+
+    Linux: `sudo apt-get install freeglut3-dev mesa-common-dev`
+
+    Mac + Xcode: These libraries should be available in the OpenGL / GLUT
+    frameworks.
+
+    Windows: http://freeglut.sourceforge.net/index.php#download
+
+2.  (Optional) qcms (Quick Color Management System)
+
+    1.  Download qcms from Mozilla / Chromium:
+        https://hg.mozilla.org/mozilla-central/file/0e7639e3bdfb/gfx/qcms
+        https://source.chromium.org/chromium/chromium/src/+/main:third_party/qcms/;drc=d4a2f8e1ed461d8fc05ed88d1ae2dc94c9773825
+    2.  Build and archive the source files as libqcms.a / qcms.lib
+    3.  Update makefile.unix / Makefile.vc
+        1.  Define WEBP_HAVE_QCMS
+        2.  Update include / library paths to reference the qcms directory.
+
+Build using makefile.unix / Makefile.vc:
+
+```shell
+$ make -f makefile.unix examples/vwebp
+> nmake /f Makefile.vc CFG=release-static \
+    ../obj/x64/release-static/bin/vwebp.exe
+```
+
+## Animation creation tool
+
+The utility `img2webp` can turn a sequence of input images (PNG, JPEG, ...) into
+an animated WebP file. It offers fine control over duration, encoding modes,
+etc.
+
+Usage:
+
+```shell
+img2webp [file_options] [[frame_options] frame_file]... [-o webp_file]
+```
+
+File-level options (only used at the start of compression):
+
+```
+-min_size ............ minimize size
+-kmax <int> .......... maximum number of frame between key-frames
+                        (0=only keyframes)
+-kmin <int> .......... minimum number of frame between key-frames
+                        (0=disable key-frames altogether)
+-mixed ............... use mixed lossy/lossless automatic mode
+-near_lossless <int> . use near-lossless image preprocessing
+                       (0..100=off), default=100
+-sharp_yuv ........... use sharper (and slower) RGB->YUV conversion
+                       (lossy only)
+-loop <int> .......... loop count (default: 0, = infinite loop)
+-v ................... verbose mode
+-h ................... this help
+-version ............. print version number and exit
+```
+
+Per-frame options (only used for subsequent images input):
+
+```
+-d <int> ............. frame duration in ms (default: 100)
+-lossless  ........... use lossless mode (default)
+-lossy ... ........... use lossy mode
+-q <float> ........... quality
+-m <int> ............. method to use
+```
+
+example: `img2webp -loop 2 in0.png -lossy in1.jpg -d 80 in2.tiff -o out.webp`
+
+Note: if a single file name is passed as the argument, the arguments will be
+tokenized from this file. The file name must not start with the character '-'.
+
+## Animated GIF conversion
+
+Animated GIF files can be converted to WebP files with animation using the
+gif2webp utility available under examples/. The files can then be viewed using
+vwebp.
+
+Usage:
+
+```shell
+gif2webp [options] gif_file -o webp_file
+```
+
+Options:
+
+```
+-h / -help ............. this help
+-lossy ................. encode image using lossy compression
+-mixed ................. for each frame in the image, pick lossy
+                         or lossless compression heuristically
+-q <float> ............. quality factor (0:small..100:big)
+-m <int> ............... compression method (0=fast, 6=slowest)
+-min_size .............. minimize output size (default:off)
+                         lossless compression by default; can be
+                         combined with -q, -m, -lossy or -mixed
+                         options
+-kmin <int> ............ min distance between key frames
+-kmax <int> ............ max distance between key frames
+-f <int> ............... filter strength (0=off..100)
+-metadata <string> ..... comma separated list of metadata to
+                         copy from the input to the output if present
+                         Valid values: all, none, icc, xmp (default)
+-loop_compatibility .... use compatibility mode for Chrome
+                         version prior to M62 (inclusive)
+-mt .................... use multi-threading if available
+
+-version ............... print version number and exit
+-v ..................... verbose
+-quiet ................. don't print anything
+```
+
+### Building
+
+With the libgif development files installed, gif2webp can be built using
+makefile.unix:
+
+```shell
+$ make -f makefile.unix examples/gif2webp
+```
+
+or using autoconf:
+
+```shell
+$ ./configure --enable-everything
+$ make
+```
+
+## Comparison of animated images
+
+Test utility anim_diff under examples/ can be used to compare two animated
+images (each can be GIF or WebP).
+
+Usage:
+
+```shell
+anim_diff <image1> <image2> [options]
+```
+
+Options:
+
+```
+-dump_frames <folder> dump decoded frames in PAM format
+-min_psnr <float> ... minimum per-frame PSNR
+-raw_comparison ..... if this flag is not used, RGB is
+                      premultiplied before comparison
+-max_diff <int> ..... maximum allowed difference per channel
+                      between corresponding pixels in subsequent
+                      frames
+-h .................. this help
+-version ............ print version number and exit
+```
+
+### Building
+
+With the libgif development files installed, anim_diff can be built using
+makefile.unix:
+
+```shell
+$ make -f makefile.unix examples/anim_diff
+```
+
+or using autoconf:
+
+```shell
+$ ./configure --enable-everything
+$ make
+```
+
+## WebP Mux tool
+
+The examples/ directory contains a tool (webpmux) for manipulating WebP files.
+The webpmux tool can be used to create an extended format WebP file and also to
+extract or strip relevant data from such a file.
+
+A list of options is available using the -help command line flag:
+
+```shell
+> webpmux -help
+Usage: webpmux -get GET_OPTIONS INPUT -o OUTPUT
+       webpmux -set SET_OPTIONS INPUT -o OUTPUT
+       webpmux -duration DURATION_OPTIONS [-duration ...]
+               INPUT -o OUTPUT
+       webpmux -strip STRIP_OPTIONS INPUT -o OUTPUT
+       webpmux -frame FRAME_OPTIONS [-frame...] [-loop LOOP_COUNT]
+               [-bgcolor BACKGROUND_COLOR] -o OUTPUT
+       webpmux -info INPUT
+       webpmux [-h|-help]
+       webpmux -version
+       webpmux argument_file_name
+
+GET_OPTIONS:
+ Extract relevant data:
+   icc       get ICC profile
+   exif      get EXIF metadata
+   xmp       get XMP metadata
+   frame n   get nth frame
+
+SET_OPTIONS:
+ Set color profile/metadata/parameters:
+   loop LOOP_COUNT            set the loop count
+   bgcolor BACKGROUND_COLOR   set the animation background color
+   icc  file.icc              set ICC profile
+   exif file.exif             set EXIF metadata
+   xmp  file.xmp              set XMP metadata
+   where:    'file.icc' contains the ICC profile to be set,
+             'file.exif' contains the EXIF metadata to be set
+             'file.xmp' contains the XMP metadata to be set
+
+DURATION_OPTIONS:
+ Set duration of selected frames:
+   duration            set duration for all frames
+   duration,frame      set duration of a particular frame
+   duration,start,end  set duration of frames in the
+                        interval [start,end])
+   where: 'duration' is the duration in milliseconds
+          'start' is the start frame index
+          'end' is the inclusive end frame index
+           The special 'end' value '0' means: last frame.
+
+STRIP_OPTIONS:
+ Strip color profile/metadata:
+   icc       strip ICC profile
+   exif      strip EXIF metadata
+   xmp       strip XMP metadata
+
+FRAME_OPTIONS(i):
+ Create animation:
+   file_i +di[+xi+yi[+mi[bi]]]
+   where:    'file_i' is the i'th animation frame (WebP format),
+             'di' is the pause duration before next frame,
+             'xi','yi' specify the image offset for this frame,
+             'mi' is the dispose method for this frame (0 or 1),
+             'bi' is the blending method for this frame (+b or -b)
+
+LOOP_COUNT:
+ Number of times to repeat the animation.
+ Valid range is 0 to 65535 [Default: 0 (infinite)].
+
+BACKGROUND_COLOR:
+ Background color of the canvas.
+  A,R,G,B
+  where:    'A', 'R', 'G' and 'B' are integers in the range 0 to 255 specifying
+            the Alpha, Red, Green and Blue component values respectively
+            [Default: 255,255,255,255]
+
+INPUT & OUTPUT are in WebP format.
+
+Note: The nature of EXIF, XMP and ICC data is not checked and is assumed to be
+valid.
+
+Note: if a single file name is passed as the argument, the arguments will be
+tokenized from this file. The file name must not start with the character '-'.
+```
--- a/external/libwebp/libwebp/doc/webp-container-spec.txt
+++ b/external/libwebp/libwebp/doc/webp-container-spec.txt
@@ -0,0 +1,870 @@
+<!--
+
+Although you may be viewing an alternate representation, this document
+is sourced in Markdown, a light-duty markup scheme, and is optimized for
+the [kramdown](https://kramdown.gettalong.org/) transformer.
+
+See the accompanying specs_generation.md. External link targets are referenced
+at the end of this file.
+
+-->
+
+
+WebP Container Specification
+============================
+
+* TOC placeholder
+{:toc}
+
+
+Introduction
+------------
+
+WebP is an image format that uses either (i) the VP8 key frame encoding to
+compress image data in a lossy way or (ii) the WebP lossless encoding. These
+encoding schemes should make it more efficient than older formats, such as JPEG,
+GIF, and PNG. It is optimized for fast image transfer over the network (for
+example, for websites). The WebP format has feature parity (color profile,
+metadata, animation, etc.) with other formats as well. This document describes
+the structure of a WebP file.
+
+The WebP container (that is, the RIFF container for WebP) allows feature support
+over and above the basic use case of WebP (that is, a file containing a single
+image encoded as a VP8 key frame). The WebP container provides additional
+support for the following:
+
+  * Lossless Compression: An image can be losslessly compressed, using the
+    WebP Lossless Format.
+
+  * Metadata: An image may have metadata stored in Exchangeable Image File
+    Format (Exif) or Extensible Metadata Platform (XMP) format.
+
+  * Transparency: An image may have transparency, that is, an alpha channel.
+
+  * Color Profile: An image may have an embedded ICC profile as described
+    by the [International Color Consortium][iccspec].
+
+  * Animation: An image may have multiple frames with pauses between them,
+    making it an animation.
+
+Terminology & Basics
+--------------------
+
+The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
+"SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this
+document are to be interpreted as described in BCP 14 [RFC 2119][] [RFC 8174][]
+when, and only when, they appear in all capitals, as shown here.
+
+A WebP file contains either a still image (that is, an encoded matrix of pixels)
+or an [animation](#animation). Optionally, it can also contain transparency
+information, a color profile and metadata. We refer to the matrix of pixels as
+the _canvas_ of the image.
+
+Bit numbering in chunk diagrams starts at `0` for the most significant bit
+('MSB 0'), as described in [RFC 1166][].
+
+Below are additional terms used throughout this document:
+
+_Reader/Writer_
+
+: Code that reads WebP files is referred to as a _reader_, while code that
+  writes them is referred to as a _writer_.
+
+_uint16_
+
+: A 16-bit, little-endian, unsigned integer.
+
+_uint24_
+
+: A 24-bit, little-endian, unsigned integer.
+
+_uint32_
+
+: A 32-bit, little-endian, unsigned integer.
+
+_FourCC_
+
+: A four-character code (FourCC) is a _uint32_ created by concatenating four
+  ASCII characters in little-endian order. This means 'aaaa' (0x61616161) and
+ 'AAAA' (0x41414141) are treated as different _FourCCs_.
+
+_1-based_
+
+: An unsigned integer field storing values offset by `-1`, for example, such a
+  field would store value _25_ as _24_.
+
+_ChunkHeader('ABCD')_
+
+: Used to describe the _FourCC_ and _Chunk Size_ header of individual chunks,
+  where 'ABCD' is the FourCC for the chunk. This element's size is 8 bytes.
+
+
+RIFF File Format
+----------------
+
+The WebP file format is based on the RIFF (Resource Interchange File Format)
+document format.
+
+The basic element of a RIFF file is a _chunk_. It consists of:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                         Chunk FourCC                          |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                          Chunk Size                           |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                         Chunk Payload                         :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Chunk FourCC: 32 bits
+
+: ASCII four-character code used for chunk identification.
+
+Chunk Size: 32 bits (_uint32_)
+
+: The size of the chunk in bytes, not including this field, the chunk
+  identifier, or padding.
+
+Chunk Payload: _Chunk Size_ bytes
+
+: The data payload. If _Chunk Size_ is odd, a single padding byte -- which MUST
+  be `0` to conform with RIFF -- is added.
+
+**Note:** RIFF has a convention that all-uppercase chunk FourCCs are standard
+chunks that apply to any RIFF file format, while FourCCs specific to a file
+format are all lowercase. WebP does not follow this convention.
+
+
+WebP File Header
+----------------
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |      'R'      |      'I'      |      'F'      |      'F'      |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                           File Size                           |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |      'W'      |      'E'      |      'B'      |      'P'      |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+'RIFF': 32 bits
+
+: The ASCII characters 'R', 'I', 'F', 'F'.
+
+File Size: 32 bits (_uint32_)
+
+: The size of the file in bytes, starting at offset 8. The maximum value of
+  this field is 2^32 minus 10 bytes and thus the size of the whole file is at
+  most 4 GiB minus 2 bytes.
+
+'WEBP': 32 bits
+
+: The ASCII characters 'W', 'E', 'B', 'P'.
+
+A WebP file MUST begin with a RIFF header with the FourCC 'WEBP'. The file size
+in the header is the total size of the chunks that follow plus `4` bytes for
+the 'WEBP' FourCC. The file SHOULD NOT contain any data after the data
+specified by _File Size_. Readers MAY parse such files, ignoring the trailing
+data. As the size of any chunk is even, the size given by the RIFF header is
+also even. The contents of individual chunks are described in the following
+sections.
+
+
+Simple File Format (Lossy)
+--------------------------
+
+This layout SHOULD be used if the image requires _lossy_ encoding and does not
+require transparency or other advanced features provided by the extended format.
+Files with this layout are smaller and supported by older software.
+
+Simple WebP (lossy) file format:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                                                               |
+    |                    WebP file header (12 bytes)                |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                        'VP8 ' Chunk                           :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+'VP8 ' Chunk:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('VP8 ')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                           VP8 data                            :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+VP8 data: _Chunk Size_ bytes
+
+: VP8 bitstream data.
+
+Note that the fourth character in the 'VP8 ' FourCC is an ASCII space (0x20).
+
+The VP8 bitstream format specification is described in [VP8 Data Format and
+Decoding Guide][rfc 6386]. Note that the VP8 frame header contains the VP8 frame
+width and height. That is assumed to be the width and height of the canvas.
+
+The VP8 specification describes how to decode the image into Y'CbCr format. To
+convert to RGB, [Recommendation BT.601][rec601] SHOULD be used. Applications MAY
+use another conversion method, but visual results may differ among decoders.
+
+
+Simple File Format (Lossless)
+-----------------------------
+
+**Note:** Older readers may not support files using the lossless format.
+
+This layout SHOULD be used if the image requires _lossless_ encoding (with an
+optional transparency channel) and does not require advanced features provided
+by the extended format.
+
+Simple WebP (lossless) file format:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                                                               |
+    |                    WebP file header (12 bytes)                |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                         'VP8L' Chunk                          :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+'VP8L' Chunk:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('VP8L')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                           VP8L data                           :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+VP8L data: _Chunk Size_ bytes
+
+: VP8L bitstream data.
+
+The current specification of the VP8L bitstream can be found at
+[WebP Lossless Bitstream Format][webpllspec]. Note that the VP8L header
+contains the VP8L image width and height. That is assumed to be the width
+and height of the canvas.
+
+
+Extended File Format
+--------------------
+
+**Note:** Older readers may not support files using the extended format.
+
+An extended format file consists of:
+
+  * A 'VP8X' Chunk with information about features used in the file.
+
+  * An optional 'ICCP' Chunk with a color profile.
+
+  * An optional 'ANIM' Chunk with animation control data.
+
+  * Image data.
+
+  * An optional 'EXIF' Chunk with Exif metadata.
+
+  * An optional 'XMP ' Chunk with XMP metadata.
+
+  * An optional list of [unknown chunks](#unknown-chunks).
+
+For a _still image_, the _image data_ consists of a single frame, which is made
+up of:
+
+  * An optional [alpha subchunk](#alpha).
+
+  * A [bitstream subchunk](#bitstream-vp8vp8l).
+
+For an _animated image_, the _image data_ consists of multiple frames. More
+details about frames can be found in the [Animation](#animation) section.
+
+All chunks SHOULD be placed in the same order as listed above. If a chunk
+appears in the wrong place, the file is invalid, but readers MAY parse the
+file, ignoring the chunks that are out of order.
+
+**Rationale:** Setting the order of chunks should allow quicker file
+parsing. For example, if an 'ALPH' Chunk does not appear in its required
+position, a decoder can choose to stop searching for it. The rule of
+ignoring late chunks should make programs that need to do a full search
+give the same results as the ones stopping early.
+
+Extended WebP file header:
+{:#extended_header}
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                                                               |
+    |                   WebP file header (12 bytes)                 |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('VP8X')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |Rsv|I|L|E|X|A|R|                   Reserved                    |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |          Canvas Width Minus One               |             ...
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    ...  Canvas Height Minus One    |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Reserved (Rsv): 2 bits
+
+: MUST be `0`. Readers MUST ignore this field.
+
+ICC profile (I): 1 bit
+
+: Set if the file contains an 'ICCP' Chunk.
+
+Alpha (L): 1 bit
+
+: Set if any of the frames of the image contain transparency information
+  ("alpha").
+
+Exif metadata (E): 1 bit
+
+: Set if the file contains Exif metadata.
+
+XMP metadata (X): 1 bit
+
+: Set if the file contains XMP metadata.
+
+Animation (A): 1 bit
+
+: Set if this is an animated image. Data in 'ANIM' and 'ANMF' Chunks should be
+  used to control the animation.
+
+Reserved (R): 1 bit
+
+: MUST be `0`. Readers MUST ignore this field.
+
+Reserved: 24 bits
+
+: MUST be `0`. Readers MUST ignore this field.
+
+Canvas Width Minus One: 24 bits
+
+: _1-based_ width of the canvas in pixels.
+  The actual canvas width is `1 + Canvas Width Minus One`.
+
+Canvas Height Minus One: 24 bits
+
+: _1-based_ height of the canvas in pixels.
+  The actual canvas height is `1 + Canvas Height Minus One`.
+
+The product of _Canvas Width_ and _Canvas Height_ MUST be at most `2^32 - 1`.
+
+Future specifications may add more fields. Unknown fields MUST be ignored.
+
+### Chunks
+
+#### Animation
+
+An animation is controlled by 'ANIM' and 'ANMF' Chunks.
+
+'ANIM' Chunk:
+{:#anim_chunk}
+
+For an animated image, this chunk contains the _global parameters_ of the
+animation.
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('ANIM')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                       Background Color                        |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |          Loop Count           |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Background Color: 32 bits (_uint32_)
+
+: The default background color of the canvas in \[Blue, Green, Red, Alpha\]
+  byte order. This color MAY be used to fill the unused space on the canvas
+  around the frames, as well as the transparent pixels of the first frame.
+  The background color is also used when the Disposal method is `1`.
+
+**Note**:
+
+  * The background color MAY contain a non-opaque alpha value, even if the
+    _Alpha_ flag in the ['VP8X' Chunk](#extended_header) is unset.
+
+  * Viewer applications SHOULD treat the background color value as a hint and
+    are not required to use it.
+
+  * The canvas is cleared at the start of each loop. The background color MAY be
+    used to achieve this.
+
+Loop Count: 16 bits (_uint16_)
+
+: The number of times to loop the animation. If it is `0`, this means
+  infinitely.
+
+This chunk MUST appear if the _Animation_ flag in the 'VP8X' Chunk is set.
+If the _Animation_ flag is not set and this chunk is present, it MUST be
+ignored.
+
+'ANMF' Chunk:
+
+For animated images, this chunk contains information about a _single_ frame.
+If the _Animation flag_ is not set, then this chunk SHOULD NOT be present.
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('ANMF')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                        Frame X                |             ...
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    ...          Frame Y            |   Frame Width Minus One     ...
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    ...             |           Frame Height Minus One              |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                 Frame Duration                |  Reserved |B|D|
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                         Frame Data                            :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Frame X: 24 bits (_uint24_)
+
+: The X coordinate of the upper left corner of the frame is `Frame X * 2`.
+
+Frame Y: 24 bits (_uint24_)
+
+: The Y coordinate of the upper left corner of the frame is `Frame Y * 2`.
+
+Frame Width Minus One: 24 bits (_uint24_)
+
+: The _1-based_ width of the frame.
+  The frame width is `1 + Frame Width Minus One`.
+
+Frame Height Minus One: 24 bits (_uint24_)
+
+: The _1-based_ height of the frame.
+  The frame height is `1 + Frame Height Minus One`.
+
+Frame Duration: 24 bits (_uint24_)
+
+: The time to wait before displaying the next frame, in 1-millisecond units.
+  Note that the interpretation of the Frame Duration of 0 (and often <= 10) is
+  defined by the implementation. Many tools and browsers assign a minimum
+  duration similar to GIF.
+
+Reserved: 6 bits
+
+: MUST be `0`. Readers MUST ignore this field.
+
+Blending method (B): 1 bit
+
+: Indicates how transparent pixels of _the current frame_ are to be blended
+  with corresponding pixels of the previous canvas:
+
+    * `0`: Use alpha-blending. After disposing of the previous frame, render the
+      current frame on the canvas using [alpha-blending](#alpha-blending). If
+      the current frame does not have an alpha channel, assume the alpha value
+      is 255, effectively replacing the rectangle.
+
+    * `1`: Do not blend. After disposing of the previous frame, render the
+      current frame on the canvas by overwriting the rectangle covered by the
+      current frame.
+
+Disposal method (D): 1 bit
+
+: Indicates how _the current frame_ is to be treated after it has been
+  displayed (before rendering the next frame) on the canvas:
+
+    * `0`: Do not dispose. Leave the canvas as is.
+
+    * `1`: Dispose to the background color. Fill the _rectangle_ on the canvas
+      covered by the _current frame_ with the background color specified in the
+      ['ANIM' Chunk](#anim_chunk).
+
+**Notes**:
+
+  * The frame disposal only applies to the _frame rectangle_, that is, the
+    rectangle defined by _Frame X_, _Frame Y_, _frame width_, and _frame
+    height_. It may or may not cover the whole canvas.
+
+{:#alpha-blending}
+  * Alpha-blending:
+
+    Given that each of the R, G, B, and A channels is 8 bits, and the RGB
+    channels are _not premultiplied_ by alpha, the formula for blending
+    'dst' onto 'src' is:
+
+~~~~~
+    blend.A = src.A + dst.A * (1 - src.A / 255)
+    if blend.A = 0 then
+      blend.RGB = 0
+    else
+      blend.RGB =
+          (src.RGB * src.A +
+           dst.RGB * dst.A * (1 - src.A / 255)) / blend.A
+~~~~~
+
+  * Alpha-blending SHOULD be done in linear color space, by taking into account
+    the [color profile](#color-profile) of the image. If the color profile is
+    not present, standard RGB (sRGB) is to be assumed. (Note that sRGB also
+    needs to be linearized due to a gamma of ~2.2.)
+
+Frame Data: _Chunk Size_ - `16` bytes
+
+: Consists of:
+
+  * An optional [alpha subchunk](#alpha) for the frame.
+
+  * A [bitstream subchunk](#bitstream-vp8vp8l) for the frame.
+
+  * An optional list of [unknown chunks](#unknown-chunks).
+
+**Note**: The 'ANMF' payload, _Frame Data_ above, consists of individual
+_padded_ chunks, as described by the [RIFF file format](#riff-file-format).
+
+#### Alpha
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('ALPH')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |Rsv| P | F | C |     Alpha Bitstream...                        |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Reserved (Rsv): 2 bits
+
+: MUST be `0`. Readers MUST ignore this field.
+
+Preprocessing (P): 2 bits
+
+: These _informative_ bits are used to signal the preprocessing that has
+  been performed during compression. The decoder can use this information to
+  for example, dither the values or smooth the gradients prior to display.
+
+    * `0`: No preprocessing.
+    * `1`: Level reduction.
+
+Decoders are not required to use this information in any specified way.
+
+Filtering method (F): 2 bits
+
+: The filtering methods used are described as follows:
+
+    * `0`: None.
+    * `1`: Horizontal filter.
+    * `2`: Vertical filter.
+    * `3`: Gradient filter.
+
+For each pixel, filtering is performed using the following calculations.
+Assume the alpha values surrounding the current `X` position are labeled as:
+
+     C | B |
+    ---+---+
+     A | X |
+
+We seek to compute the alpha value at position `X`. First, a prediction is
+made depending on the filtering method:
+
+  * Method `0`: predictor = 0
+  * Method `1`: predictor = A
+  * Method `2`: predictor = B
+  * Method `3`: predictor = clip(A + B - C)
+
+where `clip(v)` is equal to:
+
+  * 0    if v < 0,
+  * 255  if v > 255, or
+  * v    otherwise
+
+The final value is derived by adding the decompressed value `X` to the
+predictor and using modulo-256 arithmetic to wrap the \[256..511\] range
+into the \[0..255\] one:
+
+`alpha = (predictor + X) % 256`
+
+There are special cases for the left-most and top-most pixel positions. For
+example, the top-left value at location (0, 0) uses 0 as the predictor value.
+Otherwise:
+
+  * For horizontal or gradient filtering methods, the left-most pixels at
+    location (0, y) are predicted using the location (0, y-1) just above.
+  * For vertical or gradient filtering methods, the top-most pixels at
+    location (x, 0) are predicted using the location (x-1, 0) on the left.
+
+Compression method (C): 2 bits
+
+: The compression method used:
+
+    * `0`: No compression.
+    * `1`: Compressed using the WebP lossless format.
+
+Alpha bitstream: _Chunk Size_ - `1` bytes
+
+: Encoded alpha bitstream.
+
+This optional chunk contains encoded alpha data for this frame. A frame
+containing a 'VP8L' Chunk SHOULD NOT contain this chunk.
+
+**Rationale**: The transparency information is already part of the 'VP8L'
+Chunk.
+
+The alpha channel data is stored as uncompressed raw data (when the
+compression method is '0') or compressed using the lossless format
+(when the compression method is '1').
+
+  * Raw data: This consists of a byte sequence of length = width * height,
+    containing all the 8-bit transparency values in scan order.
+
+  * Lossless format compression: The byte sequence is a compressed
+    image-stream (as described in ["WebP Lossless Bitstream Format"]
+    [webpllspec]) of implicit dimensions width x height. That is, this
+    image-stream does NOT contain any headers describing the image dimensions.
+
+    **Rationale**: The dimensions are already known from other sources,
+    so storing them again would be redundant and prone to error.
+
+    Once the image-stream is decoded into Alpha, Red, Green, Blue (ARGB) color
+    values, following the process described in the lossless format
+    specification, the transparency information must be extracted from the
+    *green* channel of the ARGB quadruplet.
+
+    **Rationale**: The green channel is allowed extra transformation
+    steps in the specification -- unlike the other channels -- that can
+    improve compression.
+
+#### Bitstream (VP8/VP8L)
+
+This chunk contains compressed bitstream data for a single frame.
+
+A bitstream chunk may be either (i) a 'VP8 ' Chunk, using 'VP8 ' (note the
+significant fourth-character space) as its FourCC, _or_ (ii) a 'VP8L' Chunk,
+using 'VP8L' as its FourCC.
+
+The formats of 'VP8 ' and 'VP8L' Chunks are as described in sections
+[Simple File Format (Lossy)](#simple-file-format-lossy)
+and [Simple File Format (Lossless)](#simple-file-format-lossless), respectively.
+
+#### Color Profile
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('ICCP')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                       Color Profile                           :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Color Profile: _Chunk Size_ bytes
+
+: ICC profile.
+
+This chunk MUST appear before the image data.
+
+There SHOULD be at most one such chunk. If there are more such chunks, readers
+MAY ignore all except the first one.
+See the [ICC Specification][iccspec] for details.
+
+If this chunk is not present, sRGB SHOULD be assumed.
+
+#### Metadata
+
+Metadata can be stored in 'EXIF' or 'XMP ' Chunks.
+
+There SHOULD be at most one chunk of each type ('EXIF' and 'XMP '). If there
+are more such chunks, readers MAY ignore all except the first one.
+
+The chunks are defined as follows:
+
+'EXIF' Chunk:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('EXIF')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                        Exif Metadata                          :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+Exif Metadata: _Chunk Size_ bytes
+
+: Image metadata in Exif format.
+
+'XMP ' Chunk:
+
+     0                   1                   2                   3
+     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                      ChunkHeader('XMP ')                      |
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    :                        XMP Metadata                           :
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+XMP Metadata: _Chunk Size_ bytes
+
+: Image metadata in XMP format.
+
+Note that the fourth character in the 'XMP ' FourCC is an ASCII space (0x20).
+
+Additional guidance about handling metadata can be found in the
+Metadata Working Group's ["Guidelines for Handling Metadata"][metadata].
+
+#### Unknown Chunks
+
+A RIFF chunk (described in the [RIFF File Format](#riff-file-format) section)
+whose FourCC is different from any of the chunks described in this document, is
+considered an _unknown chunk_.
+
+**Rationale**: Allowing unknown chunks gives a provision for future extension
+of the format and also allows storage of any application-specific data.
+
+A file MAY contain unknown chunks:
+
+  * at the end of the file, as described in [Extended WebP file
+    header](#extended_header) section, or
+  * at the end of 'ANMF' Chunks, as described in the
+    [Animation](#animation) section.
+
+Readers SHOULD ignore these chunks. Writers SHOULD preserve them in their
+original order (unless they specifically intend to modify these chunks).
+
+### Canvas Assembly from Frames
+
+Here we provide an overview of how a reader MUST assemble a canvas in the case
+of an animated image.
+
+The process begins with creating a canvas using the dimensions given in the
+'VP8X' Chunk, `Canvas Width Minus One + 1` pixels wide by `Canvas Height Minus
+One + 1` pixels high. The `Loop Count` field from the 'ANIM' Chunk controls how
+many times the animation process is repeated. This is `Loop Count - 1` for
+nonzero `Loop Count` values or infinite if the `Loop Count` is zero.
+
+At the beginning of each loop iteration, the canvas is filled using the
+background color from the 'ANIM' Chunk or an application-defined color.
+
+'ANMF' Chunks contain individual frames given in display order. Before rendering
+each frame, the previous frame's `Disposal method` is applied.
+
+The rendering of the decoded frame begins at the Cartesian coordinates (`2 *
+Frame X`, `2 * Frame Y`), using the top-left corner of the canvas as the origin.
+`Frame Width Minus One + 1` pixels wide by `Frame Height Minus One + 1` pixels
+high are rendered onto the canvas using the `Blending method`.
+
+The canvas is displayed for `Frame Duration` milliseconds. This continues until
+all frames given by 'ANMF' Chunks have been displayed. A new loop iteration is
+then begun, or the canvas is left in its final state if all iterations have been
+completed.
+
+The following pseudocode illustrates the rendering process. The notation
+_VP8X.field_ means the field in the 'VP8X' Chunk with the same description.
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+assert VP8X.flags.hasAnimation
+canvas ← new image of size VP8X.canvasWidth x VP8X.canvasHeight with
+         background color ANIM.background_color.
+loop_count ← ANIM.loopCount
+dispose_method ← Dispose to background color
+if loop_count == 0:
+  loop_count = ∞
+frame_params ← nil
+assert next chunk in image_data is ANMF
+for loop = 0..loop_count - 1
+  clear canvas to ANIM.background_color or application-defined color
+  until eof or non-ANMF chunk
+    frame_params.frameX = Frame X
+    frame_params.frameY = Frame Y
+    frame_params.frameWidth = Frame Width Minus One + 1
+    frame_params.frameHeight = Frame Height Minus One + 1
+    frame_params.frameDuration = Frame Duration
+    frame_right = frame_params.frameX + frame_params.frameWidth
+    frame_bottom = frame_params.frameY + frame_params.frameHeight
+    assert VP8X.canvasWidth >= frame_right
+    assert VP8X.canvasHeight >= frame_bottom
+    for subchunk in 'Frame Data':
+      if subchunk.tag == "ALPH":
+        assert alpha subchunks not found in 'Frame Data' earlier
+        frame_params.alpha = alpha_data
+      else if subchunk.tag == "VP8 " OR subchunk.tag == "VP8L":
+        assert bitstream subchunks not found in 'Frame Data' earlier
+        frame_params.bitstream = bitstream_data
+    render frame with frame_params.alpha and frame_params.bitstream
+      on canvas with top-left corner at (frame_params.frameX,
+      frame_params.frameY), using Blending method
+      frame_params.blendingMethod.
+    canvas contains the decoded image.
+    Show the contents of the canvas for
+    frame_params.frameDuration * 1 ms.
+    dispose_method = frame_params.disposeMethod
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+
+Example File Layouts
+--------------------
+
+A lossy-encoded image with alpha may look as follows:
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+RIFF/WEBP
+- VP8X (descriptions of features used)
+- ALPH (alpha bitstream)
+- VP8 (bitstream)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A lossless-encoded image may look as follows:
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+RIFF/WEBP
+- VP8X (descriptions of features used)
+- XYZW (unknown chunk)
+- VP8L (lossless bitstream)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A lossless image with an ICC profile and XMP metadata may
+look as follows:
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+RIFF/WEBP
+- VP8X (descriptions of features used)
+- ICCP (color profile)
+- VP8L (lossless bitstream)
+- XMP  (metadata)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+An animated image with Exif metadata may look as follows:
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+RIFF/WEBP
+- VP8X (descriptions of features used)
+- ANIM (global animation parameters)
+- ANMF (frame1 parameters + data)
+- ANMF (frame2 parameters + data)
+- ANMF (frame3 parameters + data)
+- ANMF (frame4 parameters + data)
+- EXIF (metadata)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+[webpllspec]: https://chromium.googlesource.com/webm/libwebp/+/HEAD/doc/webp-lossless-bitstream-spec.txt
+[iccspec]: https://www.color.org/icc_specs2.xalter
+[metadata]: https://web.archive.org/web/20180919181934/http://www.metadataworkinggroup.org/pdf/mwg_guidance.pdf
+[rec601]: https://www.itu.int/rec/R-REC-BT.601
+[rfc 1166]: https://datatracker.ietf.org/doc/html/rfc1166
+[rfc 2119]: https://datatracker.ietf.org/doc/html/rfc2119
+[rfc 6386]: https://datatracker.ietf.org/doc/html/rfc6386
+[rfc 8174]: https://datatracker.ietf.org/doc/html/rfc8174
--- a/external/libwebp/libwebp/doc/webp-lossless-bitstream-spec.txt
+++ b/external/libwebp/libwebp/doc/webp-lossless-bitstream-spec.txt
--- a/external/libwebp/libwebp/examples/Android.mk
+++ b/external/libwebp/libwebp/examples/Android.mk
@@ -0,0 +1,96 @@
+# Ignore this file during non-NDK builds.
+ifdef NDK_ROOT
+LOCAL_PATH := $(call my-dir)
+
+################################################################################
+# libexample_util
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    example_util.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/../src
+
+LOCAL_MODULE := example_util
+
+include $(BUILD_STATIC_LIBRARY)
+
+################################################################################
+# cwebp
+
+include $(CLEAR_VARS)
+
+# Note: to enable jpeg/png encoding the sources from AOSP can be used with
+# minor modification to their Android.mk files.
+LOCAL_SRC_FILES := \
+    cwebp.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_STATIC_LIBRARIES := example_util imageio_util imagedec webpdemux webp
+
+LOCAL_MODULE := cwebp
+
+include $(BUILD_EXECUTABLE)
+
+################################################################################
+# dwebp
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    dwebp.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_STATIC_LIBRARIES := example_util imagedec imageenc webpdemux webp
+LOCAL_MODULE := dwebp
+
+include $(BUILD_EXECUTABLE)
+
+################################################################################
+# webpmux
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    webpmux.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_STATIC_LIBRARIES := example_util imageio_util webpmux webp
+
+LOCAL_MODULE := webpmux_example
+
+include $(BUILD_EXECUTABLE)
+
+################################################################################
+# img2webp
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    img2webp.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_STATIC_LIBRARIES := example_util imageio_util imagedec webpmux webpdemux \
+                          webp
+
+LOCAL_MODULE := img2webp_example
+
+include $(BUILD_EXECUTABLE)
+
+################################################################################
+# webpinfo
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    webpinfo.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_STATIC_LIBRARIES := example_util imageio_util webp
+
+LOCAL_MODULE := webpinfo_example
+
+include $(BUILD_EXECUTABLE)
+endif  # NDK_ROOT
--- a/external/libwebp/libwebp/examples/Makefile.am
+++ b/external/libwebp/libwebp/examples/Makefile.am
@@ -0,0 +1,119 @@
+AM_CPPFLAGS += -I$(top_builddir)/src -I$(top_srcdir)/src
+
+bin_PROGRAMS =
+if BUILD_DEMUX
+  bin_PROGRAMS += dwebp cwebp
+endif
+if BUILD_ANIMDIFF
+  noinst_PROGRAMS = anim_diff anim_dump
+endif
+if BUILD_GIF2WEBP
+  bin_PROGRAMS += gif2webp
+endif
+if BUILD_IMG2WEBP
+  bin_PROGRAMS += img2webp
+endif
+if BUILD_MUX
+  bin_PROGRAMS += webpmux
+endif
+if BUILD_VWEBP
+  bin_PROGRAMS += vwebp
+endif
+if BUILD_WEBPINFO
+  bin_PROGRAMS += webpinfo
+endif
+
+noinst_LTLIBRARIES = libexample_util.la
+
+libexample_util_la_SOURCES = example_util.c example_util.h
+libexample_util_la_LIBADD = ../src/libwebp.la
+
+anim_diff_SOURCES = anim_diff.c anim_util.c anim_util.h gifdec.c gifdec.h
+anim_diff_CPPFLAGS = $(AM_CPPFLAGS) $(GIF_INCLUDES)
+anim_diff_LDADD  =
+anim_diff_LDADD += ../src/demux/libwebpdemux.la
+anim_diff_LDADD += libexample_util.la
+anim_diff_LDADD += ../imageio/libimageio_util.la
+anim_diff_LDADD += $(GIF_LIBS) -lm
+
+anim_dump_SOURCES = anim_dump.c anim_util.c anim_util.h gifdec.c gifdec.h
+anim_dump_CPPFLAGS = $(AM_CPPFLAGS) $(PNG_INCLUDES)
+anim_dump_CPPFLAGS += $(GIF_INCLUDES)
+anim_dump_LDADD  =
+anim_dump_LDADD += ../src/demux/libwebpdemux.la
+anim_dump_LDADD += libexample_util.la
+anim_dump_LDADD += ../imageio/libimageio_util.la
+anim_dump_LDADD += ../imageio/libimageenc.la
+anim_dump_LDADD += $(PNG_LIBS) $(GIF_LIBS) $(TIFF_LIBS) -lm
+
+cwebp_SOURCES  = cwebp.c stopwatch.h
+cwebp_CPPFLAGS  = $(AM_CPPFLAGS) -I$(top_srcdir)
+cwebp_LDADD  =
+cwebp_LDADD += libexample_util.la
+cwebp_LDADD += ../imageio/libimageio_util.la
+cwebp_LDADD += ../imageio/libimagedec.la
+cwebp_LDADD += ../src/libwebp.la
+cwebp_LDADD += $(JPEG_LIBS) $(PNG_LIBS) $(TIFF_LIBS)
+
+dwebp_SOURCES = dwebp.c stopwatch.h
+dwebp_CPPFLAGS  = $(AM_CPPFLAGS)
+dwebp_CPPFLAGS += $(JPEG_INCLUDES) $(PNG_INCLUDES)
+dwebp_LDADD  =
+dwebp_LDADD += libexample_util.la
+dwebp_LDADD += ../imageio/libimagedec.la
+dwebp_LDADD += ../imageio/libimageenc.la
+dwebp_LDADD += ../imageio/libimageio_util.la
+dwebp_LDADD += ../src/libwebp.la
+dwebp_LDADD +=$(PNG_LIBS) $(JPEG_LIBS)
+
+gif2webp_SOURCES = gif2webp.c gifdec.c gifdec.h
+gif2webp_CPPFLAGS = $(AM_CPPFLAGS) $(GIF_INCLUDES)
+gif2webp_LDADD  =
+gif2webp_LDADD += libexample_util.la
+gif2webp_LDADD += ../imageio/libimageio_util.la
+gif2webp_LDADD += ../src/mux/libwebpmux.la
+gif2webp_LDADD += ../src/libwebp.la
+gif2webp_LDADD += $(GIF_LIBS)
+
+vwebp_SOURCES = vwebp.c
+vwebp_CPPFLAGS = $(AM_CPPFLAGS) $(GL_INCLUDES)
+vwebp_LDADD  =
+vwebp_LDADD += libexample_util.la
+vwebp_LDADD += ../imageio/libimageio_util.la
+vwebp_LDADD += ../src/demux/libwebpdemux.la
+vwebp_LDADD += $(GL_LIBS)
+
+webpmux_SOURCES = webpmux.c
+webpmux_CPPFLAGS = $(AM_CPPFLAGS)
+webpmux_LDADD  =
+webpmux_LDADD += libexample_util.la
+webpmux_LDADD += ../imageio/libimageio_util.la
+webpmux_LDADD += ../src/mux/libwebpmux.la
+webpmux_LDADD += ../src/libwebp.la
+
+img2webp_SOURCES = img2webp.c
+img2webp_CPPFLAGS = $(AM_CPPFLAGS) -I$(top_srcdir)
+img2webp_LDADD  =
+img2webp_LDADD += libexample_util.la
+img2webp_LDADD += ../imageio/libimageio_util.la
+img2webp_LDADD += ../imageio/libimagedec.la
+img2webp_LDADD += ../src/mux/libwebpmux.la
+img2webp_LDADD += ../src/libwebp.la
+img2webp_LDADD += $(PNG_LIBS) $(JPEG_LIBS) $(TIFF_LIBS)
+
+webpinfo_SOURCES = webpinfo.c
+webpinfo_CPPFLAGS = $(AM_CPPFLAGS)
+webpinfo_LDADD  =
+webpinfo_LDADD += libexample_util.la
+webpinfo_LDADD += ../imageio/libimageio_util.la
+webpinfo_LDADD += ../src/libwebp.la
+
+if BUILD_LIBWEBPDECODER
+  anim_diff_LDADD += ../src/libwebpdecoder.la
+  anim_dump_LDADD += ../src/libwebpdecoder.la
+  vwebp_LDADD += ../src/libwebpdecoder.la
+else
+  anim_diff_LDADD += ../src/libwebp.la
+  anim_dump_LDADD += ../src/libwebp.la
+  vwebp_LDADD += ../src/libwebp.la
+endif
--- a/external/libwebp/libwebp/examples/anim_diff.c
+++ b/external/libwebp/libwebp/examples/anim_diff.c
@@ -0,0 +1,317 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Checks if given pair of animated GIF/WebP images are identical:
+// That is: their reconstructed canvases match pixel-by-pixel and their other
+// animation properties (loop count etc) also match.
+//
+// example: anim_diff foo.gif bar.webp
+
+#include <assert.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>  // for 'strtod'.
+#include <string.h>  // for 'strcmp'.
+
+#include "./anim_util.h"
+#include "./example_util.h"
+#include "./unicode.h"
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#define snprintf _snprintf
+#endif
+
+// Returns true if 'a + b' will overflow.
+static int AdditionWillOverflow(int a, int b) {
+  return (b > 0) && (a > INT_MAX - b);
+}
+
+static int FramesAreEqual(const uint8_t* const rgba1,
+                          const uint8_t* const rgba2, int width, int height) {
+  const int stride = width * 4;  // Always true for 'DecodedFrame.rgba'.
+  return !memcmp(rgba1, rgba2, stride * height);
+}
+
+static WEBP_INLINE int PixelsAreSimilar(uint32_t src, uint32_t dst,
+                                        int max_allowed_diff) {
+  const int src_a = (src >> 24) & 0xff;
+  const int src_r = (src >> 16) & 0xff;
+  const int src_g = (src >> 8) & 0xff;
+  const int src_b = (src >> 0) & 0xff;
+  const int dst_a = (dst >> 24) & 0xff;
+  const int dst_r = (dst >> 16) & 0xff;
+  const int dst_g = (dst >> 8) & 0xff;
+  const int dst_b = (dst >> 0) & 0xff;
+
+  return (abs(src_r * src_a - dst_r * dst_a) <= (max_allowed_diff * 255)) &&
+         (abs(src_g * src_a - dst_g * dst_a) <= (max_allowed_diff * 255)) &&
+         (abs(src_b * src_a - dst_b * dst_a) <= (max_allowed_diff * 255)) &&
+         (abs(src_a - dst_a) <= max_allowed_diff);
+}
+
+static int FramesAreSimilar(const uint8_t* const rgba1,
+                            const uint8_t* const rgba2,
+                            int width, int height, int max_allowed_diff) {
+  int i, j;
+  assert(max_allowed_diff > 0);
+  for (j = 0; j < height; ++j) {
+    for (i = 0; i < width; ++i) {
+      const int stride = width * 4;
+      const size_t offset = j * stride + i;
+      if (!PixelsAreSimilar(rgba1[offset], rgba2[offset], max_allowed_diff)) {
+        return 0;
+      }
+    }
+  }
+  return 1;
+}
+
+// Minimize number of frames by combining successive frames that have at max
+// 'max_diff' difference per channel between corresponding pixels.
+static void MinimizeAnimationFrames(AnimatedImage* const img, int max_diff) {
+  uint32_t i;
+  for (i = 1; i < img->num_frames; ++i) {
+    DecodedFrame* const frame1 = &img->frames[i - 1];
+    DecodedFrame* const frame2 = &img->frames[i];
+    const uint8_t* const rgba1 = frame1->rgba;
+    const uint8_t* const rgba2 = frame2->rgba;
+    int should_merge_frames = 0;
+    // If merging frames will result in integer overflow for 'duration',
+    // skip merging.
+    if (AdditionWillOverflow(frame1->duration, frame2->duration)) continue;
+    if (max_diff > 0) {
+      should_merge_frames = FramesAreSimilar(rgba1, rgba2, img->canvas_width,
+                                             img->canvas_height, max_diff);
+    } else {
+      should_merge_frames =
+          FramesAreEqual(rgba1, rgba2, img->canvas_width, img->canvas_height);
+    }
+    if (should_merge_frames) {  // Merge 'i+1'th frame into 'i'th frame.
+      frame1->duration += frame2->duration;
+      if (i + 1 < img->num_frames) {
+        memmove(&img->frames[i], &img->frames[i + 1],
+                (img->num_frames - i - 1) * sizeof(*img->frames));
+      }
+      --img->num_frames;
+      --i;
+    }
+  }
+}
+
+static int CompareValues(uint32_t a, uint32_t b, const char* output_str) {
+  if (a != b) {
+    fprintf(stderr, "%s: %d vs %d\n", output_str, a, b);
+    return 0;
+  }
+  return 1;
+}
+
+static int CompareBackgroundColor(uint32_t bg1, uint32_t bg2, int premultiply) {
+  if (premultiply) {
+    const int alpha1 = (bg1 >> 24) & 0xff;
+    const int alpha2 = (bg2 >> 24) & 0xff;
+    if (alpha1 == 0 && alpha2 == 0) return 1;
+  }
+  if (bg1 != bg2) {
+    fprintf(stderr, "Background color mismatch: 0x%08x vs 0x%08x\n",
+            bg1, bg2);
+    return 0;
+  }
+  return 1;
+}
+
+// Note: As long as frame durations and reconstructed frames are identical, it
+// is OK for other aspects like offsets, dispose/blend method to vary.
+static int CompareAnimatedImagePair(const AnimatedImage* const img1,
+                                    const AnimatedImage* const img2,
+                                    int premultiply,
+                                    double min_psnr) {
+  int ok = 1;
+  const int is_multi_frame_image = (img1->num_frames > 1);
+  uint32_t i;
+
+  ok = CompareValues(img1->canvas_width, img2->canvas_width,
+                     "Canvas width mismatch") && ok;
+  ok = CompareValues(img1->canvas_height, img2->canvas_height,
+                     "Canvas height mismatch") && ok;
+  ok = CompareValues(img1->num_frames, img2->num_frames,
+                     "Frame count mismatch") && ok;
+  if (!ok) return 0;  // These are fatal failures, can't proceed.
+
+  if (is_multi_frame_image) {  // Checks relevant for multi-frame images only.
+    int max_loop_count_workaround = 0;
+    // Transcodes to webp increase the gif loop count by 1 for compatibility.
+    // When the gif has the maximum value the webp value will be off by one.
+    if ((img1->format == ANIM_GIF && img1->loop_count == 65536 &&
+         img2->format == ANIM_WEBP && img2->loop_count == 65535) ||
+        (img1->format == ANIM_WEBP && img1->loop_count == 65535 &&
+         img2->format == ANIM_GIF && img2->loop_count == 65536)) {
+      max_loop_count_workaround = 1;
+    }
+    ok = (max_loop_count_workaround ||
+          CompareValues(img1->loop_count, img2->loop_count,
+                        "Loop count mismatch")) && ok;
+    ok = CompareBackgroundColor(img1->bgcolor, img2->bgcolor,
+                                premultiply) && ok;
+  }
+
+  for (i = 0; i < img1->num_frames; ++i) {
+    // Pixel-by-pixel comparison.
+    const uint8_t* const rgba1 = img1->frames[i].rgba;
+    const uint8_t* const rgba2 = img2->frames[i].rgba;
+    int max_diff;
+    double psnr;
+    if (is_multi_frame_image) {  // Check relevant for multi-frame images only.
+      const char format[] = "Frame #%d, duration mismatch";
+      char tmp[sizeof(format) + 8];
+      ok = ok && (snprintf(tmp, sizeof(tmp), format, i) >= 0);
+      ok = ok && CompareValues(img1->frames[i].duration,
+                               img2->frames[i].duration, tmp);
+    }
+    GetDiffAndPSNR(rgba1, rgba2, img1->canvas_width, img1->canvas_height,
+                   premultiply, &max_diff, &psnr);
+    if (min_psnr > 0.) {
+      if (psnr < min_psnr) {
+        fprintf(stderr, "Frame #%d, psnr = %.2lf (min_psnr = %f)\n", i,
+                psnr, min_psnr);
+        ok = 0;
+      }
+    } else {
+      if (max_diff != 0) {
+        fprintf(stderr, "Frame #%d, max pixel diff: %d\n", i, max_diff);
+        ok = 0;
+      }
+    }
+  }
+  return ok;
+}
+
+static void Help(void) {
+  printf("Usage: anim_diff <image1> <image2> [options]\n");
+  printf("\nOptions:\n");
+  printf("  -dump_frames <folder> dump decoded frames in PAM format\n");
+  printf("  -min_psnr <float> ... minimum per-frame PSNR\n");
+  printf("  -raw_comparison ..... if this flag is not used, RGB is\n");
+  printf("                        premultiplied before comparison\n");
+  printf("  -max_diff <int> ..... maximum allowed difference per channel\n"
+         "                        between corresponding pixels in subsequent\n"
+         "                        frames\n");
+  printf("  -h .................. this help\n");
+  printf("  -version ............ print version number and exit\n");
+}
+
+int main(int argc, const char* argv[]) {
+  int return_code = -1;
+  int dump_frames = 0;
+  const char* dump_folder = NULL;
+  double min_psnr = 0.;
+  int got_input1 = 0;
+  int got_input2 = 0;
+  int premultiply = 1;
+  int max_diff = 0;
+  int i, c;
+  const char* files[2] = { NULL, NULL };
+  AnimatedImage images[2];
+
+  INIT_WARGV(argc, argv);
+
+  for (c = 1; c < argc; ++c) {
+    int parse_error = 0;
+    if (!strcmp(argv[c], "-dump_frames")) {
+      if (c < argc - 1) {
+        dump_frames = 1;
+        dump_folder = (const char*)GET_WARGV(argv, ++c);
+      } else {
+        parse_error = 1;
+      }
+    } else if (!strcmp(argv[c], "-min_psnr")) {
+      if (c < argc - 1) {
+        min_psnr = ExUtilGetFloat(argv[++c], &parse_error);
+      } else {
+        parse_error = 1;
+      }
+    } else if (!strcmp(argv[c], "-raw_comparison")) {
+      premultiply = 0;
+    } else if (!strcmp(argv[c], "-max_diff")) {
+      if (c < argc - 1) {
+        max_diff = ExUtilGetInt(argv[++c], 0, &parse_error);
+      } else {
+        parse_error = 1;
+      }
+    } else if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
+      Help();
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-version")) {
+      int dec_version, demux_version;
+      GetAnimatedImageVersions(&dec_version, &demux_version);
+      printf("WebP Decoder version: %d.%d.%d\nWebP Demux version: %d.%d.%d\n",
+             (dec_version >> 16) & 0xff, (dec_version >> 8) & 0xff,
+             (dec_version >> 0) & 0xff,
+             (demux_version >> 16) & 0xff, (demux_version >> 8) & 0xff,
+             (demux_version >> 0) & 0xff);
+      FREE_WARGV_AND_RETURN(0);
+    } else {
+      if (!got_input1) {
+        files[0] = (const char*)GET_WARGV(argv, c);
+        got_input1 = 1;
+      } else if (!got_input2) {
+        files[1] = (const char*)GET_WARGV(argv, c);
+        got_input2 = 1;
+      } else {
+        parse_error = 1;
+      }
+    }
+    if (parse_error) {
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    }
+  }
+  if (argc < 3) {
+    Help();
+    FREE_WARGV_AND_RETURN(-1);
+  }
+
+
+  if (!got_input2) {
+    Help();
+    FREE_WARGV_AND_RETURN(-1);
+  }
+
+  if (dump_frames) {
+    WPRINTF("Dumping decoded frames in: %s\n", (const W_CHAR*)dump_folder);
+  }
+
+  memset(images, 0, sizeof(images));
+  for (i = 0; i < 2; ++i) {
+    WPRINTF("Decoding file: %s\n", (const W_CHAR*)files[i]);
+    if (!ReadAnimatedImage(files[i], &images[i], dump_frames, dump_folder)) {
+      WFPRINTF(stderr, "Error decoding file: %s\n Aborting.\n",
+               (const W_CHAR*)files[i]);
+      return_code = -2;
+      goto End;
+    } else {
+      MinimizeAnimationFrames(&images[i], max_diff);
+    }
+  }
+
+  if (!CompareAnimatedImagePair(&images[0], &images[1],
+                                premultiply, min_psnr)) {
+    WFPRINTF(stderr, "\nFiles %s and %s differ.\n", (const W_CHAR*)files[0],
+             (const W_CHAR*)files[1]);
+    return_code = -3;
+  } else {
+    WPRINTF("\nFiles %s and %s are identical.\n", (const W_CHAR*)files[0],
+            (const W_CHAR*)files[1]);
+    return_code = 0;
+  }
+ End:
+  ClearAnimatedImage(&images[0]);
+  ClearAnimatedImage(&images[1]);
+  FREE_WARGV_AND_RETURN(return_code);
+}
--- a/external/libwebp/libwebp/examples/anim_dump.c
+++ b/external/libwebp/libwebp/examples/anim_dump.c
@@ -0,0 +1,121 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Decodes an animated WebP file and dumps the decoded frames as PNG or TIFF.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include <stdio.h>
+#include <string.h>  // for 'strcmp'.
+
+#include "./anim_util.h"
+#include "webp/decode.h"
+#include "../imageio/image_enc.h"
+#include "./unicode.h"
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#define snprintf _snprintf
+#endif
+
+static void Help(void) {
+  printf("Usage: anim_dump [options] files...\n");
+  printf("\nOptions:\n");
+  printf("  -folder <string> .... dump folder (default: '.')\n");
+  printf("  -prefix <string> .... prefix for dumped frames "
+                                  "(default: 'dump_')\n");
+  printf("  -tiff ............... save frames as TIFF\n");
+  printf("  -pam ................ save frames as PAM\n");
+  printf("  -h .................. this help\n");
+  printf("  -version ............ print version number and exit\n");
+}
+
+int main(int argc, const char* argv[]) {
+  int error = 0;
+  const W_CHAR* dump_folder = TO_W_CHAR(".");
+  const W_CHAR* prefix = TO_W_CHAR("dump_");
+  const W_CHAR* suffix = TO_W_CHAR("png");
+  WebPOutputFileFormat format = PNG;
+  int c;
+
+  INIT_WARGV(argc, argv);
+
+  if (argc < 2) {
+    Help();
+    FREE_WARGV_AND_RETURN(-1);
+  }
+
+  for (c = 1; !error && c < argc; ++c) {
+    if (!strcmp(argv[c], "-folder")) {
+      if (c + 1 == argc) {
+        fprintf(stderr, "missing argument after option '%s'\n", argv[c]);
+        error = 1;
+        break;
+      }
+      dump_folder = GET_WARGV(argv, ++c);
+    } else if (!strcmp(argv[c], "-prefix")) {
+      if (c + 1 == argc) {
+        fprintf(stderr, "missing argument after option '%s'\n", argv[c]);
+        error = 1;
+        break;
+      }
+      prefix = GET_WARGV(argv, ++c);
+    } else if (!strcmp(argv[c], "-tiff")) {
+      format = TIFF;
+      suffix = TO_W_CHAR("tiff");
+    } else if (!strcmp(argv[c], "-pam")) {
+      format = PAM;
+      suffix = TO_W_CHAR("pam");
+    } else if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
+      Help();
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-version")) {
+      int dec_version, demux_version;
+      GetAnimatedImageVersions(&dec_version, &demux_version);
+      printf("WebP Decoder version: %d.%d.%d\nWebP Demux version: %d.%d.%d\n",
+             (dec_version >> 16) & 0xff, (dec_version >> 8) & 0xff,
+             (dec_version >> 0) & 0xff,
+             (demux_version >> 16) & 0xff, (demux_version >> 8) & 0xff,
+             (demux_version >> 0) & 0xff);
+      FREE_WARGV_AND_RETURN(0);
+    } else {
+      uint32_t i;
+      AnimatedImage image;
+      const W_CHAR* const file = GET_WARGV(argv, c);
+      memset(&image, 0, sizeof(image));
+      WPRINTF("Decoding file: %s as %s/%sxxxx.%s\n",
+              file, dump_folder, prefix, suffix);
+      if (!ReadAnimatedImage((const char*)file, &image, 0, NULL)) {
+        WFPRINTF(stderr, "Error decoding file: %s\n Aborting.\n", file);
+        error = 1;
+        break;
+      }
+      for (i = 0; !error && i < image.num_frames; ++i) {
+        W_CHAR out_file[1024];
+        WebPDecBuffer buffer;
+        WebPInitDecBuffer(&buffer);
+        buffer.colorspace = MODE_RGBA;
+        buffer.is_external_memory = 1;
+        buffer.width = image.canvas_width;
+        buffer.height = image.canvas_height;
+        buffer.u.RGBA.rgba = image.frames[i].rgba;
+        buffer.u.RGBA.stride = buffer.width * sizeof(uint32_t);
+        buffer.u.RGBA.size = buffer.u.RGBA.stride * buffer.height;
+        WSNPRINTF(out_file, sizeof(out_file), "%s/%s%.4d.%s",
+                  dump_folder, prefix, i, suffix);
+        if (!WebPSaveImage(&buffer, format, (const char*)out_file)) {
+          WFPRINTF(stderr, "Error while saving image '%s'\n", out_file);
+          error = 1;
+        }
+        WebPFreeDecBuffer(&buffer);
+      }
+      ClearAnimatedImage(&image);
+    }
+  }
+  FREE_WARGV_AND_RETURN(error ? 1 : 0);
+}
--- a/external/libwebp/libwebp/examples/anim_util.c
+++ b/external/libwebp/libwebp/examples/anim_util.c
@@ -0,0 +1,782 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Utilities for animated images
+
+#include "./anim_util.h"
+
+#include <assert.h>
+#include <math.h>
+#include <stdio.h>
+#include <string.h>
+
+#if defined(WEBP_HAVE_GIF)
+#include <gif_lib.h>
+#endif
+#include "webp/format_constants.h"
+#include "webp/decode.h"
+#include "webp/demux.h"
+#include "../imageio/imageio_util.h"
+#include "./gifdec.h"
+#include "./unicode.h"
+#include "./unicode_gif.h"
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#define snprintf _snprintf
+#endif
+
+static const int kNumChannels = 4;
+
+// -----------------------------------------------------------------------------
+// Common utilities.
+
+#if defined(WEBP_HAVE_GIF)
+// Returns true if the frame covers the full canvas.
+static int IsFullFrame(int width, int height,
+                       int canvas_width, int canvas_height) {
+  return (width == canvas_width && height == canvas_height);
+}
+#endif // WEBP_HAVE_GIF
+
+static int CheckSizeForOverflow(uint64_t size) {
+  return (size == (size_t)size);
+}
+
+static int AllocateFrames(AnimatedImage* const image, uint32_t num_frames) {
+  uint32_t i;
+  uint8_t* mem = NULL;
+  DecodedFrame* frames = NULL;
+  const uint64_t rgba_size =
+      (uint64_t)image->canvas_width * kNumChannels * image->canvas_height;
+  const uint64_t total_size = (uint64_t)num_frames * rgba_size * sizeof(*mem);
+  const uint64_t total_frame_size = (uint64_t)num_frames * sizeof(*frames);
+  if (!CheckSizeForOverflow(total_size) ||
+      !CheckSizeForOverflow(total_frame_size)) {
+    return 0;
+  }
+  mem = (uint8_t*)WebPMalloc((size_t)total_size);
+  frames = (DecodedFrame*)WebPMalloc((size_t)total_frame_size);
+
+  if (mem == NULL || frames == NULL) {
+    WebPFree(mem);
+    WebPFree(frames);
+    return 0;
+  }
+  WebPFree(image->raw_mem);
+  image->num_frames = num_frames;
+  image->frames = frames;
+  for (i = 0; i < num_frames; ++i) {
+    frames[i].rgba = mem + i * rgba_size;
+    frames[i].duration = 0;
+    frames[i].is_key_frame = 0;
+  }
+  image->raw_mem = mem;
+  return 1;
+}
+
+void ClearAnimatedImage(AnimatedImage* const image) {
+  if (image != NULL) {
+    WebPFree(image->raw_mem);
+    WebPFree(image->frames);
+    image->num_frames = 0;
+    image->frames = NULL;
+    image->raw_mem = NULL;
+  }
+}
+
+#if defined(WEBP_HAVE_GIF)
+// Clear the canvas to transparent.
+static void ZeroFillCanvas(uint8_t* rgba,
+                           uint32_t canvas_width, uint32_t canvas_height) {
+  memset(rgba, 0, canvas_width * kNumChannels * canvas_height);
+}
+
+// Clear given frame rectangle to transparent.
+static void ZeroFillFrameRect(uint8_t* rgba, int rgba_stride, int x_offset,
+                              int y_offset, int width, int height) {
+  int j;
+  assert(width * kNumChannels <= rgba_stride);
+  rgba += y_offset * rgba_stride + x_offset * kNumChannels;
+  for (j = 0; j < height; ++j) {
+    memset(rgba, 0, width * kNumChannels);
+    rgba += rgba_stride;
+  }
+}
+
+// Copy width * height pixels from 'src' to 'dst'.
+static void CopyCanvas(const uint8_t* src, uint8_t* dst,
+                       uint32_t width, uint32_t height) {
+  assert(src != NULL && dst != NULL);
+  memcpy(dst, src, width * kNumChannels * height);
+}
+
+// Copy pixels in the given rectangle from 'src' to 'dst' honoring the 'stride'.
+static void CopyFrameRectangle(const uint8_t* src, uint8_t* dst, int stride,
+                               int x_offset, int y_offset,
+                               int width, int height) {
+  int j;
+  const int width_in_bytes = width * kNumChannels;
+  const size_t offset = y_offset * stride + x_offset * kNumChannels;
+  assert(width_in_bytes <= stride);
+  src += offset;
+  dst += offset;
+  for (j = 0; j < height; ++j) {
+    memcpy(dst, src, width_in_bytes);
+    src += stride;
+    dst += stride;
+  }
+}
+#endif // WEBP_HAVE_GIF
+
+// Canonicalize all transparent pixels to transparent black to aid comparison.
+static void CleanupTransparentPixels(uint32_t* rgba,
+                                     uint32_t width, uint32_t height) {
+  const uint32_t* const rgba_end = rgba + width * height;
+  while (rgba < rgba_end) {
+    const uint8_t alpha = (*rgba >> 24) & 0xff;
+    if (alpha == 0) {
+      *rgba = 0;
+    }
+    ++rgba;
+  }
+}
+
+// Dump frame to a PAM file. Returns true on success.
+static int DumpFrame(const char filename[], const char dump_folder[],
+                     uint32_t frame_num, const uint8_t rgba[],
+                     int canvas_width, int canvas_height) {
+  int ok = 0;
+  size_t max_len;
+  int y;
+  const W_CHAR* base_name = NULL;
+  W_CHAR* file_name = NULL;
+  FILE* f = NULL;
+  const char* row;
+
+  if (dump_folder == NULL) dump_folder = (const char*)TO_W_CHAR(".");
+
+  base_name = WSTRRCHR(filename, '/');
+  base_name = (base_name == NULL) ? (const W_CHAR*)filename : base_name + 1;
+  max_len = WSTRLEN(dump_folder) + 1 + WSTRLEN(base_name)
+          + strlen("_frame_") + strlen(".pam") + 8;
+  file_name = (W_CHAR*)WebPMalloc(max_len * sizeof(*file_name));
+  if (file_name == NULL) goto End;
+
+  if (WSNPRINTF(file_name, max_len, "%s/%s_frame_%d.pam",
+                (const W_CHAR*)dump_folder, base_name, frame_num) < 0) {
+    fprintf(stderr, "Error while generating file name\n");
+    goto End;
+  }
+
+  f = WFOPEN(file_name, "wb");
+  if (f == NULL) {
+    WFPRINTF(stderr, "Error opening file for writing: %s\n", file_name);
+    ok = 0;
+    goto End;
+  }
+  if (fprintf(f, "P7\nWIDTH %d\nHEIGHT %d\n"
+              "DEPTH 4\nMAXVAL 255\nTUPLTYPE RGB_ALPHA\nENDHDR\n",
+              canvas_width, canvas_height) < 0) {
+    WFPRINTF(stderr, "Write error for file %s\n", file_name);
+    goto End;
+  }
+  row = (const char*)rgba;
+  for (y = 0; y < canvas_height; ++y) {
+    if (fwrite(row, canvas_width * kNumChannels, 1, f) != 1) {
+      WFPRINTF(stderr, "Error writing to file: %s\n", file_name);
+      goto End;
+    }
+    row += canvas_width * kNumChannels;
+  }
+  ok = 1;
+ End:
+  if (f != NULL) fclose(f);
+  WebPFree(file_name);
+  return ok;
+}
+
+// -----------------------------------------------------------------------------
+// WebP Decoding.
+
+// Returns true if this is a valid WebP bitstream.
+static int IsWebP(const WebPData* const webp_data) {
+  return (WebPGetInfo(webp_data->bytes, webp_data->size, NULL, NULL) != 0);
+}
+
+// Read animated WebP bitstream 'webp_data' into 'AnimatedImage' struct.
+static int ReadAnimatedWebP(const char filename[],
+                            const WebPData* const webp_data,
+                            AnimatedImage* const image, int dump_frames,
+                            const char dump_folder[]) {
+  int ok = 0;
+  int dump_ok = 1;
+  uint32_t frame_index = 0;
+  int prev_frame_timestamp = 0;
+  WebPAnimDecoder* dec;
+  WebPAnimInfo anim_info;
+
+  memset(image, 0, sizeof(*image));
+
+  dec = WebPAnimDecoderNew(webp_data, NULL);
+  if (dec == NULL) {
+    WFPRINTF(stderr, "Error parsing image: %s\n", (const W_CHAR*)filename);
+    goto End;
+  }
+
+  if (!WebPAnimDecoderGetInfo(dec, &anim_info)) {
+    fprintf(stderr, "Error getting global info about the animation\n");
+    goto End;
+  }
+
+  // Animation properties.
+  image->canvas_width = anim_info.canvas_width;
+  image->canvas_height = anim_info.canvas_height;
+  image->loop_count = anim_info.loop_count;
+  image->bgcolor = anim_info.bgcolor;
+
+  // Allocate frames.
+  if (!AllocateFrames(image, anim_info.frame_count)) goto End;
+
+  // Decode frames.
+  while (WebPAnimDecoderHasMoreFrames(dec)) {
+    DecodedFrame* curr_frame;
+    uint8_t* curr_rgba;
+    uint8_t* frame_rgba;
+    int timestamp;
+
+    if (!WebPAnimDecoderGetNext(dec, &frame_rgba, &timestamp)) {
+      fprintf(stderr, "Error decoding frame #%u\n", frame_index);
+      goto End;
+    }
+    assert(frame_index < anim_info.frame_count);
+    curr_frame = &image->frames[frame_index];
+    curr_rgba = curr_frame->rgba;
+    curr_frame->duration = timestamp - prev_frame_timestamp;
+    curr_frame->is_key_frame = 0;  // Unused.
+    memcpy(curr_rgba, frame_rgba,
+           image->canvas_width * kNumChannels * image->canvas_height);
+
+    // Needed only because we may want to compare with GIF later.
+    CleanupTransparentPixels((uint32_t*)curr_rgba,
+                             image->canvas_width, image->canvas_height);
+
+    if (dump_frames && dump_ok) {
+      dump_ok = DumpFrame(filename, dump_folder, frame_index, curr_rgba,
+                          image->canvas_width, image->canvas_height);
+      if (!dump_ok) {  // Print error once, but continue decode loop.
+        fprintf(stderr, "Error dumping frames to %s\n", dump_folder);
+      }
+    }
+
+    ++frame_index;
+    prev_frame_timestamp = timestamp;
+  }
+  ok = dump_ok;
+  if (ok) image->format = ANIM_WEBP;
+
+ End:
+  WebPAnimDecoderDelete(dec);
+  return ok;
+}
+
+// -----------------------------------------------------------------------------
+// GIF Decoding.
+
+#if defined(WEBP_HAVE_GIF)
+
+// Returns true if this is a valid GIF bitstream.
+static int IsGIF(const WebPData* const data) {
+  return data->size > GIF_STAMP_LEN &&
+         (!memcmp(GIF_STAMP, data->bytes, GIF_STAMP_LEN) ||
+          !memcmp(GIF87_STAMP, data->bytes, GIF_STAMP_LEN) ||
+          !memcmp(GIF89_STAMP, data->bytes, GIF_STAMP_LEN));
+}
+
+// GIFLIB_MAJOR is only defined in libgif >= 4.2.0.
+#if defined(GIFLIB_MAJOR) && defined(GIFLIB_MINOR)
+# define LOCAL_GIF_VERSION ((GIFLIB_MAJOR << 8) | GIFLIB_MINOR)
+# define LOCAL_GIF_PREREQ(maj, min) \
+    (LOCAL_GIF_VERSION >= (((maj) << 8) | (min)))
+#else
+# define LOCAL_GIF_VERSION 0
+# define LOCAL_GIF_PREREQ(maj, min) 0
+#endif
+
+#if !LOCAL_GIF_PREREQ(5, 0)
+
+// Added in v5.0
+typedef struct {
+  int DisposalMode;
+#define DISPOSAL_UNSPECIFIED      0       // No disposal specified
+#define DISPOSE_DO_NOT            1       // Leave image in place
+#define DISPOSE_BACKGROUND        2       // Set area to background color
+#define DISPOSE_PREVIOUS          3       // Restore to previous content
+  int UserInputFlag;       // User confirmation required before disposal
+  int DelayTime;           // Pre-display delay in 0.01sec units
+  int TransparentColor;    // Palette index for transparency, -1 if none
+#define NO_TRANSPARENT_COLOR     -1
+} GraphicsControlBlock;
+
+static int DGifExtensionToGCB(const size_t GifExtensionLength,
+                              const GifByteType* GifExtension,
+                              GraphicsControlBlock* gcb) {
+  if (GifExtensionLength != 4) {
+    return GIF_ERROR;
+  }
+  gcb->DisposalMode = (GifExtension[0] >> 2) & 0x07;
+  gcb->UserInputFlag = (GifExtension[0] & 0x02) != 0;
+  gcb->DelayTime = GifExtension[1] | (GifExtension[2] << 8);
+  if (GifExtension[0] & 0x01) {
+    gcb->TransparentColor = (int)GifExtension[3];
+  } else {
+    gcb->TransparentColor = NO_TRANSPARENT_COLOR;
+  }
+  return GIF_OK;
+}
+
+static int DGifSavedExtensionToGCB(GifFileType* GifFile, int ImageIndex,
+                                   GraphicsControlBlock* gcb) {
+  int i;
+  if (ImageIndex < 0 || ImageIndex > GifFile->ImageCount - 1) {
+    return GIF_ERROR;
+  }
+  gcb->DisposalMode = DISPOSAL_UNSPECIFIED;
+  gcb->UserInputFlag = 0;
+  gcb->DelayTime = 0;
+  gcb->TransparentColor = NO_TRANSPARENT_COLOR;
+
+  for (i = 0; i < GifFile->SavedImages[ImageIndex].ExtensionBlockCount; i++) {
+    ExtensionBlock* ep = &GifFile->SavedImages[ImageIndex].ExtensionBlocks[i];
+    if (ep->Function == GRAPHICS_EXT_FUNC_CODE) {
+      return DGifExtensionToGCB(
+          ep->ByteCount, (const GifByteType*)ep->Bytes, gcb);
+    }
+  }
+  return GIF_ERROR;
+}
+
+#define CONTINUE_EXT_FUNC_CODE 0x00
+
+// Signature was changed in v5.0
+#define DGifOpenFileName(a, b) DGifOpenFileName(a)
+
+#endif  // !LOCAL_GIF_PREREQ(5, 0)
+
+// Signature changed in v5.1
+#if !LOCAL_GIF_PREREQ(5, 1)
+#define DGifCloseFile(a, b) DGifCloseFile(a)
+#endif
+
+static int IsKeyFrameGIF(const GifImageDesc* prev_desc, int prev_dispose,
+                         const DecodedFrame* const prev_frame,
+                         int canvas_width, int canvas_height) {
+  if (prev_frame == NULL) return 1;
+  if (prev_dispose == DISPOSE_BACKGROUND) {
+    if (IsFullFrame(prev_desc->Width, prev_desc->Height,
+                    canvas_width, canvas_height)) {
+      return 1;
+    }
+    if (prev_frame->is_key_frame) return 1;
+  }
+  return 0;
+}
+
+static int GetTransparentIndexGIF(GifFileType* gif) {
+  GraphicsControlBlock first_gcb;
+  memset(&first_gcb, 0, sizeof(first_gcb));
+  DGifSavedExtensionToGCB(gif, 0, &first_gcb);
+  return first_gcb.TransparentColor;
+}
+
+static uint32_t GetBackgroundColorGIF(GifFileType* gif) {
+  const int transparent_index = GetTransparentIndexGIF(gif);
+  const ColorMapObject* const color_map = gif->SColorMap;
+  if (transparent_index != NO_TRANSPARENT_COLOR &&
+      gif->SBackGroundColor == transparent_index) {
+    return 0x00000000;  // Special case: transparent black.
+  } else if (color_map == NULL || color_map->Colors == NULL
+             || gif->SBackGroundColor >= color_map->ColorCount) {
+    return 0xffffffff;  // Invalid: assume white.
+  } else {
+    const GifColorType color = color_map->Colors[gif->SBackGroundColor];
+    return (0xffu << 24) |
+           (color.Red << 16) |
+           (color.Green << 8) |
+           (color.Blue << 0);
+  }
+}
+
+// Find appropriate app extension and get loop count from the next extension.
+// We use Chrome's interpretation of the 'loop_count' semantics:
+//   if not present -> loop once
+//   if present and loop_count == 0, return 0 ('infinite').
+//   if present and loop_count != 0, it's the number of *extra* loops
+//     so we need to return loop_count + 1 as total loop number.
+static uint32_t GetLoopCountGIF(const GifFileType* const gif) {
+  int i;
+  for (i = 0; i < gif->ImageCount; ++i) {
+    const SavedImage* const image = &gif->SavedImages[i];
+    int j;
+    for (j = 0; (j + 1) < image->ExtensionBlockCount; ++j) {
+      const ExtensionBlock* const eb1 = image->ExtensionBlocks + j;
+      const ExtensionBlock* const eb2 = image->ExtensionBlocks + j + 1;
+      const char* const signature = (const char*)eb1->Bytes;
+      const int signature_is_ok =
+          (eb1->Function == APPLICATION_EXT_FUNC_CODE) &&
+          (eb1->ByteCount == 11) &&
+          (!memcmp(signature, "NETSCAPE2.0", 11) ||
+           !memcmp(signature, "ANIMEXTS1.0", 11));
+      if (signature_is_ok &&
+          eb2->Function == CONTINUE_EXT_FUNC_CODE && eb2->ByteCount >= 3 &&
+          eb2->Bytes[0] == 1) {
+        const uint32_t extra_loop = ((uint32_t)(eb2->Bytes[2]) << 8) +
+                                    ((uint32_t)(eb2->Bytes[1]) << 0);
+        return (extra_loop > 0) ? extra_loop + 1 : 0;
+      }
+    }
+  }
+  return 1;  // Default.
+}
+
+// Get duration of 'n'th frame in milliseconds.
+static int GetFrameDurationGIF(GifFileType* gif, int n) {
+  GraphicsControlBlock gcb;
+  memset(&gcb, 0, sizeof(gcb));
+  DGifSavedExtensionToGCB(gif, n, &gcb);
+  return gcb.DelayTime * 10;
+}
+
+// Returns true if frame 'target' completely covers 'covered'.
+static int CoversFrameGIF(const GifImageDesc* const target,
+                          const GifImageDesc* const covered) {
+  return target->Left <= covered->Left &&
+         covered->Left + covered->Width <= target->Left + target->Width &&
+         target->Top <= covered->Top &&
+         covered->Top + covered->Height <= target->Top + target->Height;
+}
+
+static void RemapPixelsGIF(const uint8_t* const src,
+                           const ColorMapObject* const cmap,
+                           int transparent_color, int len, uint8_t* dst) {
+  int i;
+  for (i = 0; i < len; ++i) {
+    if (src[i] != transparent_color) {
+      // If a pixel in the current frame is transparent, we don't modify it, so
+      // that we can see-through the corresponding pixel from an earlier frame.
+      const GifColorType c = cmap->Colors[src[i]];
+      dst[4 * i + 0] = c.Red;
+      dst[4 * i + 1] = c.Green;
+      dst[4 * i + 2] = c.Blue;
+      dst[4 * i + 3] = 0xff;
+    }
+  }
+}
+
+static int ReadFrameGIF(const SavedImage* const gif_image,
+                        const ColorMapObject* cmap, int transparent_color,
+                        int out_stride, uint8_t* const dst) {
+  const GifImageDesc* image_desc = &gif_image->ImageDesc;
+  const uint8_t* in;
+  uint8_t* out;
+  int j;
+
+  if (image_desc->ColorMap) cmap = image_desc->ColorMap;
+
+  if (cmap == NULL || cmap->ColorCount != (1 << cmap->BitsPerPixel)) {
+    fprintf(stderr, "Potentially corrupt color map.\n");
+    return 0;
+  }
+
+  in = (const uint8_t*)gif_image->RasterBits;
+  out = dst + image_desc->Top * out_stride + image_desc->Left * kNumChannels;
+
+  for (j = 0; j < image_desc->Height; ++j) {
+    RemapPixelsGIF(in, cmap, transparent_color, image_desc->Width, out);
+    in += image_desc->Width;
+    out += out_stride;
+  }
+  return 1;
+}
+
+// Read animated GIF bitstream from 'filename' into 'AnimatedImage' struct.
+static int ReadAnimatedGIF(const char filename[], AnimatedImage* const image,
+                           int dump_frames, const char dump_folder[]) {
+  uint32_t frame_count;
+  uint32_t canvas_width, canvas_height;
+  uint32_t i;
+  int gif_error;
+  GifFileType* gif;
+
+  gif = DGifOpenFileUnicode((const W_CHAR*)filename, NULL);
+  if (gif == NULL) {
+    WFPRINTF(stderr, "Could not read file: %s.\n", (const W_CHAR*)filename);
+    return 0;
+  }
+
+  gif_error = DGifSlurp(gif);
+  if (gif_error != GIF_OK) {
+    WFPRINTF(stderr, "Could not parse image: %s.\n", (const W_CHAR*)filename);
+    GIFDisplayError(gif, gif_error);
+    DGifCloseFile(gif, NULL);
+    return 0;
+  }
+
+  // Animation properties.
+  image->canvas_width = (uint32_t)gif->SWidth;
+  image->canvas_height = (uint32_t)gif->SHeight;
+  if (image->canvas_width > MAX_CANVAS_SIZE ||
+      image->canvas_height > MAX_CANVAS_SIZE) {
+    fprintf(stderr, "Invalid canvas dimension: %d x %d\n",
+            image->canvas_width, image->canvas_height);
+    DGifCloseFile(gif, NULL);
+    return 0;
+  }
+  image->loop_count = GetLoopCountGIF(gif);
+  image->bgcolor = GetBackgroundColorGIF(gif);
+
+  frame_count = (uint32_t)gif->ImageCount;
+  if (frame_count == 0) {
+    DGifCloseFile(gif, NULL);
+    return 0;
+  }
+
+  if (image->canvas_width == 0 || image->canvas_height == 0) {
+    image->canvas_width = gif->SavedImages[0].ImageDesc.Width;
+    image->canvas_height = gif->SavedImages[0].ImageDesc.Height;
+    gif->SavedImages[0].ImageDesc.Left = 0;
+    gif->SavedImages[0].ImageDesc.Top = 0;
+    if (image->canvas_width == 0 || image->canvas_height == 0) {
+      fprintf(stderr, "Invalid canvas size in GIF.\n");
+      DGifCloseFile(gif, NULL);
+      return 0;
+    }
+  }
+  // Allocate frames.
+  if (!AllocateFrames(image, frame_count)) {
+    DGifCloseFile(gif, NULL);
+    return 0;
+  }
+
+  canvas_width = image->canvas_width;
+  canvas_height = image->canvas_height;
+
+  // Decode and reconstruct frames.
+  for (i = 0; i < frame_count; ++i) {
+    const int canvas_width_in_bytes = canvas_width * kNumChannels;
+    const SavedImage* const curr_gif_image = &gif->SavedImages[i];
+    GraphicsControlBlock curr_gcb;
+    DecodedFrame* curr_frame;
+    uint8_t* curr_rgba;
+
+    memset(&curr_gcb, 0, sizeof(curr_gcb));
+    DGifSavedExtensionToGCB(gif, i, &curr_gcb);
+
+    curr_frame = &image->frames[i];
+    curr_rgba = curr_frame->rgba;
+    curr_frame->duration = GetFrameDurationGIF(gif, i);
+    // Force frames with a small or no duration to 100ms to be consistent
+    // with web browsers and other transcoding tools (like gif2webp itself).
+    if (curr_frame->duration <= 10) curr_frame->duration = 100;
+
+    if (i == 0) {  // Initialize as transparent.
+      curr_frame->is_key_frame = 1;
+      ZeroFillCanvas(curr_rgba, canvas_width, canvas_height);
+    } else {
+      DecodedFrame* const prev_frame = &image->frames[i - 1];
+      const GifImageDesc* const prev_desc = &gif->SavedImages[i - 1].ImageDesc;
+      GraphicsControlBlock prev_gcb;
+      memset(&prev_gcb, 0, sizeof(prev_gcb));
+      DGifSavedExtensionToGCB(gif, i - 1, &prev_gcb);
+
+      curr_frame->is_key_frame =
+          IsKeyFrameGIF(prev_desc, prev_gcb.DisposalMode, prev_frame,
+                        canvas_width, canvas_height);
+
+      if (curr_frame->is_key_frame) {  // Initialize as transparent.
+        ZeroFillCanvas(curr_rgba, canvas_width, canvas_height);
+      } else {
+        int prev_frame_disposed, curr_frame_opaque;
+        int prev_frame_completely_covered;
+        // Initialize with previous canvas.
+        uint8_t* const prev_rgba = image->frames[i - 1].rgba;
+        CopyCanvas(prev_rgba, curr_rgba, canvas_width, canvas_height);
+
+        // Dispose previous frame rectangle.
+        prev_frame_disposed =
+            (prev_gcb.DisposalMode == DISPOSE_BACKGROUND ||
+             prev_gcb.DisposalMode == DISPOSE_PREVIOUS);
+        curr_frame_opaque =
+            (curr_gcb.TransparentColor == NO_TRANSPARENT_COLOR);
+        prev_frame_completely_covered =
+            curr_frame_opaque &&
+            CoversFrameGIF(&curr_gif_image->ImageDesc, prev_desc);
+
+        if (prev_frame_disposed && !prev_frame_completely_covered) {
+          switch (prev_gcb.DisposalMode) {
+            case DISPOSE_BACKGROUND: {
+              ZeroFillFrameRect(curr_rgba, canvas_width_in_bytes,
+                                prev_desc->Left, prev_desc->Top,
+                                prev_desc->Width, prev_desc->Height);
+              break;
+            }
+            case DISPOSE_PREVIOUS: {
+              int src_frame_num = i - 2;
+              while (src_frame_num >= 0) {
+                GraphicsControlBlock src_frame_gcb;
+                memset(&src_frame_gcb, 0, sizeof(src_frame_gcb));
+                DGifSavedExtensionToGCB(gif, src_frame_num, &src_frame_gcb);
+                if (src_frame_gcb.DisposalMode != DISPOSE_PREVIOUS) break;
+                --src_frame_num;
+              }
+              if (src_frame_num >= 0) {
+                // Restore pixels inside previous frame rectangle to
+                // corresponding pixels in source canvas.
+                uint8_t* const src_frame_rgba =
+                    image->frames[src_frame_num].rgba;
+                CopyFrameRectangle(src_frame_rgba, curr_rgba,
+                                   canvas_width_in_bytes,
+                                   prev_desc->Left, prev_desc->Top,
+                                   prev_desc->Width, prev_desc->Height);
+              } else {
+                // Source canvas doesn't exist. So clear previous frame
+                // rectangle to background.
+                ZeroFillFrameRect(curr_rgba, canvas_width_in_bytes,
+                                  prev_desc->Left, prev_desc->Top,
+                                  prev_desc->Width, prev_desc->Height);
+              }
+              break;
+            }
+            default:
+              break;  // Nothing to do.
+          }
+        }
+      }
+    }
+
+    // Decode current frame.
+    if (!ReadFrameGIF(curr_gif_image, gif->SColorMap, curr_gcb.TransparentColor,
+                      canvas_width_in_bytes, curr_rgba)) {
+      DGifCloseFile(gif, NULL);
+      return 0;
+    }
+
+    if (dump_frames) {
+      if (!DumpFrame(filename, dump_folder, i, curr_rgba,
+                     canvas_width, canvas_height)) {
+        DGifCloseFile(gif, NULL);
+        return 0;
+      }
+    }
+  }
+  image->format = ANIM_GIF;
+  DGifCloseFile(gif, NULL);
+  return 1;
+}
+
+#else
+
+static int IsGIF(const WebPData* const data) {
+  (void)data;
+  return 0;
+}
+
+static int ReadAnimatedGIF(const char filename[], AnimatedImage* const image,
+                           int dump_frames, const char dump_folder[]) {
+  (void)filename;
+  (void)image;
+  (void)dump_frames;
+  (void)dump_folder;
+  fprintf(stderr, "GIF support not compiled. Please install the libgif-dev "
+          "package before building.\n");
+  return 0;
+}
+
+#endif  // WEBP_HAVE_GIF
+
+// -----------------------------------------------------------------------------
+
+int ReadAnimatedImage(const char filename[], AnimatedImage* const image,
+                      int dump_frames, const char dump_folder[]) {
+  int ok = 0;
+  WebPData webp_data;
+
+  WebPDataInit(&webp_data);
+  memset(image, 0, sizeof(*image));
+
+  if (!ImgIoUtilReadFile(filename, &webp_data.bytes, &webp_data.size)) {
+    WFPRINTF(stderr, "Error reading file: %s\n", (const W_CHAR*)filename);
+    return 0;
+  }
+
+  if (IsWebP(&webp_data)) {
+    ok = ReadAnimatedWebP(filename, &webp_data, image, dump_frames,
+                          dump_folder);
+  } else if (IsGIF(&webp_data)) {
+    ok = ReadAnimatedGIF(filename, image, dump_frames, dump_folder);
+  } else {
+    WFPRINTF(stderr,
+             "Unknown file type: %s. Supported file types are WebP and GIF\n",
+             (const W_CHAR*)filename);
+    ok = 0;
+  }
+  if (!ok) ClearAnimatedImage(image);
+  WebPDataClear(&webp_data);
+  return ok;
+}
+
+static void Accumulate(double v1, double v2, double* const max_diff,
+                       double* const sse) {
+  const double diff = fabs(v1 - v2);
+  if (diff > *max_diff) *max_diff = diff;
+  *sse += diff * diff;
+}
+
+void GetDiffAndPSNR(const uint8_t rgba1[], const uint8_t rgba2[],
+                    uint32_t width, uint32_t height, int premultiply,
+                    int* const max_diff, double* const psnr) {
+  const uint32_t stride = width * kNumChannels;
+  const int kAlphaChannel = kNumChannels - 1;
+  double f_max_diff = 0.;
+  double sse = 0.;
+  uint32_t x, y;
+  for (y = 0; y < height; ++y) {
+    for (x = 0; x < stride; x += kNumChannels) {
+      int k;
+      const size_t offset = (size_t)y * stride + x;
+      const int alpha1 = rgba1[offset + kAlphaChannel];
+      const int alpha2 = rgba2[offset + kAlphaChannel];
+      Accumulate(alpha1, alpha2, &f_max_diff, &sse);
+      if (!premultiply) {
+        for (k = 0; k < kAlphaChannel; ++k) {
+          Accumulate(rgba1[offset + k], rgba2[offset + k], &f_max_diff, &sse);
+        }
+      } else {
+        // premultiply R/G/B channels with alpha value
+        for (k = 0; k < kAlphaChannel; ++k) {
+          Accumulate(rgba1[offset + k] * alpha1 / 255.,
+                     rgba2[offset + k] * alpha2 / 255.,
+                     &f_max_diff, &sse);
+        }
+      }
+    }
+  }
+  *max_diff = (int)f_max_diff;
+  if (*max_diff == 0) {
+    *psnr = 99.;  // PSNR when images are identical.
+  } else {
+    sse /= stride * height;
+    *psnr = 4.3429448 * log(255. * 255. / sse);
+  }
+}
+
+void GetAnimatedImageVersions(int* const decoder_version,
+                              int* const demux_version) {
+  *decoder_version = WebPGetDecoderVersion();
+  *demux_version = WebPGetDemuxVersion();
+}
--- a/external/libwebp/libwebp/examples/anim_util.h
+++ b/external/libwebp/libwebp/examples/anim_util.h
@@ -0,0 +1,73 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Utilities for animated images
+
+#ifndef WEBP_EXAMPLES_ANIM_UTIL_H_
+#define WEBP_EXAMPLES_ANIM_UTIL_H_
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+  ANIM_GIF,
+  ANIM_WEBP
+} AnimatedFileFormat;
+
+typedef struct {
+  uint8_t* rgba;         // Decoded and reconstructed full frame.
+  int duration;          // Frame duration in milliseconds.
+  int is_key_frame;      // True if this frame is a key-frame.
+} DecodedFrame;
+
+typedef struct {
+  AnimatedFileFormat format;
+  uint32_t canvas_width;
+  uint32_t canvas_height;
+  uint32_t bgcolor;
+  uint32_t loop_count;
+  DecodedFrame* frames;
+  uint32_t num_frames;
+  void* raw_mem;
+} AnimatedImage;
+
+// Deallocate everything in 'image' (but not the object itself).
+void ClearAnimatedImage(AnimatedImage* const image);
+
+// Read animated image file into 'AnimatedImage' struct.
+// If 'dump_frames' is true, dump frames to 'dump_folder'.
+// Previous content of 'image' is obliterated.
+// Upon successful return, content of 'image' must be deleted by
+// calling 'ClearAnimatedImage'.
+int ReadAnimatedImage(const char filename[], AnimatedImage* const image,
+                      int dump_frames, const char dump_folder[]);
+
+// Given two RGBA buffers, calculate max pixel difference and PSNR.
+// If 'premultiply' is true, R/G/B values will be pre-multiplied by the
+// transparency before comparison.
+void GetDiffAndPSNR(const uint8_t rgba1[], const uint8_t rgba2[],
+                    uint32_t width, uint32_t height, int premultiply,
+                    int* const max_diff, double* const psnr);
+
+// Return library versions used by anim_util.
+void GetAnimatedImageVersions(int* const decoder_version,
+                              int* const demux_version);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_EXAMPLES_ANIM_UTIL_H_
--- a/external/libwebp/libwebp/examples/cwebp.c
+++ b/external/libwebp/libwebp/examples/cwebp.c
--- a/external/libwebp/libwebp/examples/dwebp.c
+++ b/external/libwebp/libwebp/examples/dwebp.c
@@ -0,0 +1,421 @@
+// Copyright 2010 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Command-line tool for decoding a WebP image.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "../examples/example_util.h"
+#include "../imageio/image_enc.h"
+#include "../imageio/webpdec.h"
+#include "./stopwatch.h"
+#include "./unicode.h"
+
+static int verbose = 0;
+static int quiet = 0;
+#ifndef WEBP_DLL
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern void* VP8GetCPUInfo;   // opaque forward declaration.
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+#endif  // WEBP_DLL
+
+
+static int SaveOutput(const WebPDecBuffer* const buffer,
+                      WebPOutputFileFormat format, const char* const out_file) {
+  const int use_stdout = (out_file != NULL) && !WSTRCMP(out_file, "-");
+  int ok = 1;
+  Stopwatch stop_watch;
+
+  if (verbose) {
+    StopwatchReset(&stop_watch);
+  }
+  ok = WebPSaveImage(buffer, format, out_file);
+
+  if (ok) {
+    if (!quiet) {
+      if (use_stdout) {
+        fprintf(stderr, "Saved to stdout\n");
+      } else {
+        WFPRINTF(stderr, "Saved file %s\n", (const W_CHAR*)out_file);
+      }
+    }
+    if (verbose) {
+      const double write_time = StopwatchReadAndReset(&stop_watch);
+      fprintf(stderr, "Time to write output: %.3fs\n", write_time);
+    }
+  } else {
+    if (use_stdout) {
+      fprintf(stderr, "Error writing to stdout !!\n");
+    } else {
+      WFPRINTF(stderr, "Error writing file %s !!\n", (const W_CHAR*)out_file);
+    }
+  }
+  return ok;
+}
+
+static void Help(void) {
+  printf("Usage: dwebp in_file [options] [-o out_file]\n\n"
+         "Decodes the WebP image file to PNG format [Default].\n"
+         "Note: Animated WebP files are not supported.\n\n"
+         "Use following options to convert into alternate image formats:\n"
+         "  -pam ......... save the raw RGBA samples as a color PAM\n"
+         "  -ppm ......... save the raw RGB samples as a color PPM\n"
+         "  -bmp ......... save as uncompressed BMP format\n"
+         "  -tiff ........ save as uncompressed TIFF format\n"
+         "  -pgm ......... save the raw YUV samples as a grayscale PGM\n"
+         "                 file with IMC4 layout\n"
+         "  -yuv ......... save the raw YUV samples in flat layout\n"
+         "\n"
+         " Other options are:\n"
+         "  -version ..... print version number and exit\n"
+         "  -nofancy ..... don't use the fancy YUV420 upscaler\n"
+         "  -nofilter .... disable in-loop filtering\n"
+         "  -nodither .... disable dithering\n"
+         "  -dither <d> .. dithering strength (in 0..100)\n"
+         "  -alpha_dither  use alpha-plane dithering if needed\n"
+         "  -mt .......... use multi-threading\n"
+         "  -crop <x> <y> <w> <h> ... crop output with the given rectangle\n"
+         "  -resize <w> <h> ......... resize output (*after* any cropping)\n"
+         "  -flip ........ flip the output vertically\n"
+         "  -alpha ....... only save the alpha plane\n"
+         "  -incremental . use incremental decoding (useful for tests)\n"
+         "  -h ........... this help message\n"
+         "  -v ........... verbose (e.g. print encoding/decoding times)\n"
+         "  -quiet ....... quiet mode, don't print anything\n"
+#ifndef WEBP_DLL
+         "  -noasm ....... disable all assembly optimizations\n"
+#endif
+        );
+}
+
+static const char* const kFormatType[] = {
+  "unspecified", "lossy", "lossless"
+};
+
+static uint8_t* AllocateExternalBuffer(WebPDecoderConfig* config,
+                                       WebPOutputFileFormat format,
+                                       int use_external_memory) {
+  uint8_t* external_buffer = NULL;
+  WebPDecBuffer* const output_buffer = &config->output;
+  int w = config->input.width;
+  int h = config->input.height;
+  if (config->options.use_scaling) {
+    w = config->options.scaled_width;
+    h = config->options.scaled_height;
+  } else if (config->options.use_cropping) {
+    w = config->options.crop_width;
+    h = config->options.crop_height;
+  }
+  if (format >= RGB && format <= rgbA_4444) {
+    const int bpp = (format == RGB || format == BGR) ? 3
+                  : (format == RGBA_4444 || format == rgbA_4444 ||
+                     format == RGB_565) ? 2
+                  : 4;
+    uint32_t stride = bpp * w + 7;   // <- just for exercising
+    external_buffer = (uint8_t*)WebPMalloc(stride * h);
+    if (external_buffer == NULL) return NULL;
+    output_buffer->u.RGBA.stride = stride;
+    output_buffer->u.RGBA.size = stride * h;
+    output_buffer->u.RGBA.rgba = external_buffer;
+  } else {    // YUV and YUVA
+    const int has_alpha = WebPIsAlphaMode(output_buffer->colorspace);
+    uint8_t* tmp;
+    uint32_t stride = w + 3;
+    uint32_t uv_stride = (w + 1) / 2 + 13;
+    uint32_t total_size = stride * h * (has_alpha ? 2 : 1)
+                        + 2 * uv_stride * (h + 1) / 2;
+    assert(format >= YUV && format <= YUVA);
+    external_buffer = (uint8_t*)WebPMalloc(total_size);
+    if (external_buffer == NULL) return NULL;
+    tmp = external_buffer;
+    output_buffer->u.YUVA.y = tmp;
+    output_buffer->u.YUVA.y_stride = stride;
+    output_buffer->u.YUVA.y_size = stride * h;
+    tmp += output_buffer->u.YUVA.y_size;
+    if (has_alpha) {
+      output_buffer->u.YUVA.a = tmp;
+      output_buffer->u.YUVA.a_stride = stride;
+      output_buffer->u.YUVA.a_size = stride * h;
+      tmp += output_buffer->u.YUVA.a_size;
+    } else {
+      output_buffer->u.YUVA.a = NULL;
+      output_buffer->u.YUVA.a_stride = 0;
+    }
+    output_buffer->u.YUVA.u = tmp;
+    output_buffer->u.YUVA.u_stride = uv_stride;
+    output_buffer->u.YUVA.u_size = uv_stride * (h + 1) / 2;
+    tmp += output_buffer->u.YUVA.u_size;
+
+    output_buffer->u.YUVA.v = tmp;
+    output_buffer->u.YUVA.v_stride = uv_stride;
+    output_buffer->u.YUVA.v_size = uv_stride * (h + 1) / 2;
+    tmp += output_buffer->u.YUVA.v_size;
+    assert(tmp <= external_buffer + total_size);
+  }
+  output_buffer->is_external_memory = use_external_memory;
+  return external_buffer;
+}
+
+int main(int argc, const char* argv[]) {
+  int ok = 0;
+  const char* in_file = NULL;
+  const char* out_file = NULL;
+
+  WebPDecoderConfig config;
+  WebPDecBuffer* const output_buffer = &config.output;
+  WebPBitstreamFeatures* const bitstream = &config.input;
+  WebPOutputFileFormat format = PNG;
+  uint8_t* external_buffer = NULL;
+  int use_external_memory = 0;
+  const uint8_t* data = NULL;
+
+  int incremental = 0;
+  int c;
+
+  INIT_WARGV(argc, argv);
+
+  if (!WebPInitDecoderConfig(&config)) {
+    fprintf(stderr, "Library version mismatch!\n");
+    FREE_WARGV_AND_RETURN(-1);
+  }
+
+  for (c = 1; c < argc; ++c) {
+    int parse_error = 0;
+    if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
+      Help();
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-o") && c < argc - 1) {
+      out_file = (const char*)GET_WARGV(argv, ++c);
+    } else if (!strcmp(argv[c], "-alpha")) {
+      format = ALPHA_PLANE_ONLY;
+    } else if (!strcmp(argv[c], "-nofancy")) {
+      config.options.no_fancy_upsampling = 1;
+    } else if (!strcmp(argv[c], "-nofilter")) {
+      config.options.bypass_filtering = 1;
+    } else if (!strcmp(argv[c], "-pam")) {
+      format = PAM;
+    } else if (!strcmp(argv[c], "-ppm")) {
+      format = PPM;
+    } else if (!strcmp(argv[c], "-bmp")) {
+      format = BMP;
+    } else if (!strcmp(argv[c], "-tiff")) {
+      format = TIFF;
+    } else if (!strcmp(argv[c], "-quiet")) {
+      quiet = 1;
+    } else if (!strcmp(argv[c], "-version")) {
+      const int version = WebPGetDecoderVersion();
+      printf("%d.%d.%d\n",
+             (version >> 16) & 0xff, (version >> 8) & 0xff, version & 0xff);
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-pgm")) {
+      format = PGM;
+    } else if (!strcmp(argv[c], "-yuv")) {
+      format = RAW_YUV;
+    } else if (!strcmp(argv[c], "-pixel_format") && c < argc - 1) {
+      const char* const fmt = argv[++c];
+      if      (!strcmp(fmt, "RGB"))  format = RGB;
+      else if (!strcmp(fmt, "RGBA")) format = RGBA;
+      else if (!strcmp(fmt, "BGR"))  format = BGR;
+      else if (!strcmp(fmt, "BGRA")) format = BGRA;
+      else if (!strcmp(fmt, "ARGB")) format = ARGB;
+      else if (!strcmp(fmt, "RGBA_4444")) format = RGBA_4444;
+      else if (!strcmp(fmt, "RGB_565")) format = RGB_565;
+      else if (!strcmp(fmt, "rgbA")) format = rgbA;
+      else if (!strcmp(fmt, "bgrA")) format = bgrA;
+      else if (!strcmp(fmt, "Argb")) format = Argb;
+      else if (!strcmp(fmt, "rgbA_4444")) format = rgbA_4444;
+      else if (!strcmp(fmt, "YUV"))  format = YUV;
+      else if (!strcmp(fmt, "YUVA")) format = YUVA;
+      else {
+        fprintf(stderr, "Can't parse pixel_format %s\n", fmt);
+        parse_error = 1;
+      }
+    } else if (!strcmp(argv[c], "-external_memory") && c < argc - 1) {
+      use_external_memory = ExUtilGetInt(argv[++c], 0, &parse_error);
+      parse_error |= (use_external_memory > 2 || use_external_memory < 0);
+      if (parse_error) {
+        fprintf(stderr, "Can't parse 'external_memory' value %s\n", argv[c]);
+      }
+    } else if (!strcmp(argv[c], "-mt")) {
+      config.options.use_threads = 1;
+    } else if (!strcmp(argv[c], "-alpha_dither")) {
+      config.options.alpha_dithering_strength = 100;
+    } else if (!strcmp(argv[c], "-nodither")) {
+      config.options.dithering_strength = 0;
+    } else if (!strcmp(argv[c], "-dither") && c < argc - 1) {
+      config.options.dithering_strength =
+          ExUtilGetInt(argv[++c], 0, &parse_error);
+    } else if (!strcmp(argv[c], "-crop") && c < argc - 4) {
+      config.options.use_cropping = 1;
+      config.options.crop_left   = ExUtilGetInt(argv[++c], 0, &parse_error);
+      config.options.crop_top    = ExUtilGetInt(argv[++c], 0, &parse_error);
+      config.options.crop_width  = ExUtilGetInt(argv[++c], 0, &parse_error);
+      config.options.crop_height = ExUtilGetInt(argv[++c], 0, &parse_error);
+    } else if ((!strcmp(argv[c], "-scale") || !strcmp(argv[c], "-resize")) &&
+               c < argc - 2) {  // '-scale' is left for compatibility
+      config.options.use_scaling = 1;
+      config.options.scaled_width  = ExUtilGetInt(argv[++c], 0, &parse_error);
+      config.options.scaled_height = ExUtilGetInt(argv[++c], 0, &parse_error);
+    } else if (!strcmp(argv[c], "-flip")) {
+      config.options.flip = 1;
+    } else if (!strcmp(argv[c], "-v")) {
+      verbose = 1;
+#ifndef WEBP_DLL
+    } else if (!strcmp(argv[c], "-noasm")) {
+      VP8GetCPUInfo = NULL;
+#endif
+    } else if (!strcmp(argv[c], "-incremental")) {
+      incremental = 1;
+    } else if (!strcmp(argv[c], "--")) {
+      if (c < argc - 1) in_file = (const char*)GET_WARGV(argv, ++c);
+      break;
+    } else if (argv[c][0] == '-') {
+      fprintf(stderr, "Unknown option '%s'\n", argv[c]);
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    } else {
+      in_file = (const char*)GET_WARGV(argv, c);
+    }
+
+    if (parse_error) {
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    }
+  }
+
+  if (in_file == NULL) {
+    fprintf(stderr, "missing input file!!\n");
+    Help();
+    FREE_WARGV_AND_RETURN(-1);
+  }
+
+  if (quiet) verbose = 0;
+
+  {
+    VP8StatusCode status = VP8_STATUS_OK;
+    size_t data_size = 0;
+    if (!LoadWebP(in_file, &data, &data_size, bitstream)) {
+      FREE_WARGV_AND_RETURN(-1);
+    }
+
+    switch (format) {
+      case PNG:
+#ifdef HAVE_WINCODEC_H
+        output_buffer->colorspace = bitstream->has_alpha ? MODE_BGRA : MODE_BGR;
+#else
+        output_buffer->colorspace = bitstream->has_alpha ? MODE_RGBA : MODE_RGB;
+#endif
+        break;
+      case PAM:
+        output_buffer->colorspace = MODE_RGBA;
+        break;
+      case PPM:
+        output_buffer->colorspace = MODE_RGB;  // drops alpha for PPM
+        break;
+      case BMP:
+        output_buffer->colorspace = bitstream->has_alpha ? MODE_BGRA : MODE_BGR;
+        break;
+      case TIFF:
+        output_buffer->colorspace = bitstream->has_alpha ? MODE_RGBA : MODE_RGB;
+        break;
+      case PGM:
+      case RAW_YUV:
+        output_buffer->colorspace = bitstream->has_alpha ? MODE_YUVA : MODE_YUV;
+        break;
+      case ALPHA_PLANE_ONLY:
+        output_buffer->colorspace = MODE_YUVA;
+        break;
+      // forced modes:
+      case RGB: output_buffer->colorspace = MODE_RGB; break;
+      case RGBA: output_buffer->colorspace = MODE_RGBA; break;
+      case BGR: output_buffer->colorspace = MODE_BGR; break;
+      case BGRA: output_buffer->colorspace = MODE_BGRA; break;
+      case ARGB: output_buffer->colorspace = MODE_ARGB; break;
+      case RGBA_4444: output_buffer->colorspace = MODE_RGBA_4444; break;
+      case RGB_565: output_buffer->colorspace = MODE_RGB_565; break;
+      case rgbA: output_buffer->colorspace = MODE_rgbA; break;
+      case bgrA: output_buffer->colorspace = MODE_bgrA; break;
+      case Argb: output_buffer->colorspace = MODE_Argb; break;
+      case rgbA_4444: output_buffer->colorspace = MODE_rgbA_4444; break;
+      case YUV: output_buffer->colorspace = MODE_YUV; break;
+      case YUVA: output_buffer->colorspace = MODE_YUVA; break;
+      default: goto Exit;
+    }
+
+    if (use_external_memory > 0 && format >= RGB) {
+      external_buffer = AllocateExternalBuffer(&config, format,
+                                               use_external_memory);
+      if (external_buffer == NULL) goto Exit;
+    }
+
+    {
+      Stopwatch stop_watch;
+      if (verbose) StopwatchReset(&stop_watch);
+
+      if (incremental) {
+        status = DecodeWebPIncremental(data, data_size, &config);
+      } else {
+        status = DecodeWebP(data, data_size, &config);
+      }
+      if (verbose) {
+        const double decode_time = StopwatchReadAndReset(&stop_watch);
+        fprintf(stderr, "Time to decode picture: %.3fs\n", decode_time);
+      }
+    }
+
+    ok = (status == VP8_STATUS_OK);
+    if (!ok) {
+      PrintWebPError(in_file, status);
+      goto Exit;
+    }
+  }
+
+  if (out_file != NULL) {
+    if (!quiet) {
+      WFPRINTF(stderr, "Decoded %s.", (const W_CHAR*)in_file);
+      fprintf(stderr, " Dimensions: %d x %d %s. Format: %s. Now saving...\n",
+              output_buffer->width, output_buffer->height,
+              bitstream->has_alpha ? " (with alpha)" : "",
+              kFormatType[bitstream->format]);
+    }
+    ok = SaveOutput(output_buffer, format, out_file);
+  } else {
+    if (!quiet) {
+      WFPRINTF(stderr, "File %s can be decoded ", (const W_CHAR*)in_file);
+      fprintf(stderr, "(dimensions: %d x %d %s. Format: %s).\n",
+              output_buffer->width, output_buffer->height,
+              bitstream->has_alpha ? " (with alpha)" : "",
+              kFormatType[bitstream->format]);
+      fprintf(stderr, "Nothing written; "
+                      "use -o flag to save the result as e.g. PNG.\n");
+    }
+  }
+ Exit:
+  WebPFreeDecBuffer(output_buffer);
+  WebPFree((void*)external_buffer);
+  WebPFree((void*)data);
+  FREE_WARGV_AND_RETURN(ok ? 0 : -1);
+}
+
+//------------------------------------------------------------------------------
--- a/external/libwebp/libwebp/examples/example_util.c
+++ b/external/libwebp/libwebp/examples/example_util.c
@@ -0,0 +1,139 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Utility functions used by the example programs.
+//
+
+#include "./example_util.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/mux_types.h"
+#include "../imageio/imageio_util.h"
+
+//------------------------------------------------------------------------------
+// String parsing
+
+uint32_t ExUtilGetUInt(const char* const v, int base, int* const error) {
+  char* end = NULL;
+  const uint32_t n = (v != NULL) ? (uint32_t)strtoul(v, &end, base) : 0u;
+  if (end == v && error != NULL && !*error) {
+    *error = 1;
+    fprintf(stderr, "Error! '%s' is not an integer.\n",
+            (v != NULL) ? v : "(null)");
+  }
+  return n;
+}
+
+int ExUtilGetInt(const char* const v, int base, int* const error) {
+  return (int)ExUtilGetUInt(v, base, error);
+}
+
+int ExUtilGetInts(const char* v, int base, int max_output, int output[]) {
+  int n, error = 0;
+  for (n = 0; v != NULL && n < max_output; ++n) {
+    const int value = ExUtilGetInt(v, base, &error);
+    if (error) return -1;
+    output[n] = value;
+    v = strchr(v, ',');
+    if (v != NULL) ++v;   // skip over the trailing ','
+  }
+  return n;
+}
+
+float ExUtilGetFloat(const char* const v, int* const error) {
+  char* end = NULL;
+  const float f = (v != NULL) ? (float)strtod(v, &end) : 0.f;
+  if (end == v && error != NULL && !*error) {
+    *error = 1;
+    fprintf(stderr, "Error! '%s' is not a floating point number.\n",
+            (v != NULL) ? v : "(null)");
+  }
+  return f;
+}
+
+//------------------------------------------------------------------------------
+
+static void ResetCommandLineArguments(int argc, const char* argv[],
+                                      CommandLineArguments* const args) {
+  assert(args != NULL);
+  args->argc_ = argc;
+  args->argv_ = argv;
+  args->own_argv_ = 0;
+  WebPDataInit(&args->argv_data_);
+}
+
+void ExUtilDeleteCommandLineArguments(CommandLineArguments* const args) {
+  if (args != NULL) {
+    if (args->own_argv_) {
+      WebPFree((void*)args->argv_);
+      WebPDataClear(&args->argv_data_);
+    }
+    ResetCommandLineArguments(0, NULL, args);
+  }
+}
+
+#define MAX_ARGC 16384
+int ExUtilInitCommandLineArguments(int argc, const char* argv[],
+                                   CommandLineArguments* const args) {
+  if (args == NULL || argv == NULL) return 0;
+  ResetCommandLineArguments(argc, argv, args);
+  if (argc == 1 && argv[0][0] != '-') {
+    char* cur;
+    const char sep[] = " \t\r\n\f\v";
+
+#if defined(_WIN32) && defined(_UNICODE)
+    fprintf(stderr,
+            "Error: Reading arguments from a file is a feature unavailable "
+            "with Unicode binaries.\n");
+    return 0;
+#endif
+
+    if (!ExUtilReadFileToWebPData(argv[0], &args->argv_data_)) {
+      return 0;
+    }
+    args->own_argv_ = 1;
+    args->argv_ = (const char**)WebPMalloc(MAX_ARGC * sizeof(*args->argv_));
+    if (args->argv_ == NULL) {
+      ExUtilDeleteCommandLineArguments(args);
+      return 0;
+    }
+
+    argc = 0;
+    for (cur = strtok((char*)args->argv_data_.bytes, sep);
+         cur != NULL;
+         cur = strtok(NULL, sep)) {
+      if (argc == MAX_ARGC) {
+        fprintf(stderr, "ERROR: Arguments limit %d reached\n", MAX_ARGC);
+        ExUtilDeleteCommandLineArguments(args);
+        return 0;
+      }
+      assert(strlen(cur) != 0);
+      args->argv_[argc++] = cur;
+    }
+    args->argc_ = argc;
+  }
+  return 1;
+}
+
+//------------------------------------------------------------------------------
+
+int ExUtilReadFileToWebPData(const char* const filename,
+                             WebPData* const webp_data) {
+  const uint8_t* data;
+  size_t size;
+  if (webp_data == NULL) return 0;
+  if (!ImgIoUtilReadFile(filename, &data, &size)) return 0;
+  webp_data->bytes = data;
+  webp_data->size = size;
+  return 1;
+}
--- a/external/libwebp/libwebp/examples/example_util.h
+++ b/external/libwebp/libwebp/examples/example_util.h
@@ -0,0 +1,70 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Utility functions used by the example programs.
+//
+
+#ifndef WEBP_EXAMPLES_EXAMPLE_UTIL_H_
+#define WEBP_EXAMPLES_EXAMPLE_UTIL_H_
+
+#include "webp/types.h"
+#include "webp/mux_types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+//------------------------------------------------------------------------------
+// String parsing
+
+// Parses 'v' using strto(ul|l|d)(). If error is non-NULL, '*error' is set to
+// true on failure while on success it is left unmodified to allow chaining of
+// calls. An error is only printed on the first occurrence.
+uint32_t ExUtilGetUInt(const char* const v, int base, int* const error);
+int ExUtilGetInt(const char* const v, int base, int* const error);
+float ExUtilGetFloat(const char* const v, int* const error);
+
+// This variant of ExUtilGetInt() will parse multiple integers from a
+// comma-separated list. Up to 'max_output' integers are parsed.
+// The result is placed in the output[] array, and the number of integers
+// actually parsed is returned, or -1 if an error occurred.
+int ExUtilGetInts(const char* v, int base, int max_output, int output[]);
+
+// Reads a file named 'filename' into a WebPData structure. The content of
+// webp_data is overwritten. Returns false in case of error.
+int ExUtilReadFileToWebPData(const char* const filename,
+                             WebPData* const webp_data);
+
+//------------------------------------------------------------------------------
+// Command-line arguments
+
+typedef struct {
+  int argc_;
+  const char** argv_;
+  WebPData argv_data_;
+  int own_argv_;
+} CommandLineArguments;
+
+// Initializes the structure from the command-line parameters. If there is
+// only one parameter and it does not start with a '-', then it is assumed to
+// be a file name. This file will be read and tokenized into command-line
+// arguments. The content of 'args' is overwritten.
+// Returns false in case of error (memory allocation failure, non
+// existing file, too many arguments, ...).
+int ExUtilInitCommandLineArguments(int argc, const char* argv[],
+                                   CommandLineArguments* const args);
+
+// Deallocate all memory and reset 'args'.
+void ExUtilDeleteCommandLineArguments(CommandLineArguments* const args);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_EXAMPLES_EXAMPLE_UTIL_H_
--- a/external/libwebp/libwebp/examples/gif2webp.c
+++ b/external/libwebp/libwebp/examples/gif2webp.c
@@ -0,0 +1,609 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  simple tool to convert animated GIFs to WebP
+//
+// Authors: Skal (pascal.massimino@gmail.com)
+//          Urvang (urvang@google.com)
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#ifdef WEBP_HAVE_GIF
+
+#if defined(HAVE_UNISTD_H) && HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include <gif_lib.h>
+#include "webp/encode.h"
+#include "webp/mux.h"
+#include "../examples/example_util.h"
+#include "../imageio/imageio_util.h"
+#include "./gifdec.h"
+#include "./unicode.h"
+#include "./unicode_gif.h"
+
+#if !defined(STDIN_FILENO)
+#define STDIN_FILENO 0
+#endif
+
+//------------------------------------------------------------------------------
+
+static int transparent_index = GIF_INDEX_INVALID;  // Opaque by default.
+
+static const char* const kErrorMessages[-WEBP_MUX_NOT_ENOUGH_DATA + 1] = {
+  "WEBP_MUX_NOT_FOUND", "WEBP_MUX_INVALID_ARGUMENT", "WEBP_MUX_BAD_DATA",
+  "WEBP_MUX_MEMORY_ERROR", "WEBP_MUX_NOT_ENOUGH_DATA"
+};
+
+static const char* ErrorString(WebPMuxError err) {
+  assert(err <= WEBP_MUX_NOT_FOUND && err >= WEBP_MUX_NOT_ENOUGH_DATA);
+  return kErrorMessages[-err];
+}
+
+enum {
+  METADATA_ICC  = (1 << 0),
+  METADATA_XMP  = (1 << 1),
+  METADATA_ALL  = METADATA_ICC | METADATA_XMP
+};
+
+//------------------------------------------------------------------------------
+
+static void Help(void) {
+  printf("Usage:\n");
+  printf(" gif2webp [options] gif_file -o webp_file\n");
+  printf("Options:\n");
+  printf("  -h / -help ............. this help\n");
+  printf("  -lossy ................. encode image using lossy compression\n");
+  printf("  -mixed ................. for each frame in the image, pick lossy\n"
+         "                           or lossless compression heuristically\n");
+  printf("  -q <float> ............. quality factor (0:small..100:big)\n");
+  printf("  -m <int> ............... compression method (0=fast, 6=slowest)\n");
+  printf("  -min_size .............. minimize output size (default:off)\n"
+         "                           lossless compression by default; can be\n"
+         "                           combined with -q, -m, -lossy or -mixed\n"
+         "                           options\n");
+  printf("  -kmin <int> ............ min distance between key frames\n");
+  printf("  -kmax <int> ............ max distance between key frames\n");
+  printf("  -f <int> ............... filter strength (0=off..100)\n");
+  printf("  -metadata <string> ..... comma separated list of metadata to\n");
+  printf("                           ");
+  printf("copy from the input to the output if present\n");
+  printf("                           ");
+  printf("Valid values: all, none, icc, xmp (default)\n");
+  printf("  -loop_compatibility .... use compatibility mode for Chrome\n");
+  printf("                           version prior to M62 (inclusive)\n");
+  printf("  -mt .................... use multi-threading if available\n");
+  printf("\n");
+  printf("  -version ............... print version number and exit\n");
+  printf("  -v ..................... verbose\n");
+  printf("  -quiet ................. don't print anything\n");
+  printf("\n");
+}
+
+//------------------------------------------------------------------------------
+
+int main(int argc, const char* argv[]) {
+  int verbose = 0;
+  int gif_error = GIF_ERROR;
+  WebPMuxError err = WEBP_MUX_OK;
+  int ok = 0;
+  const W_CHAR* in_file = NULL, *out_file = NULL;
+  GifFileType* gif = NULL;
+  int frame_duration = 0;
+  int frame_timestamp = 0;
+  GIFDisposeMethod orig_dispose = GIF_DISPOSE_NONE;
+
+  WebPPicture frame;                // Frame rectangle only (not disposed).
+  WebPPicture curr_canvas;          // Not disposed.
+  WebPPicture prev_canvas;          // Disposed.
+
+  WebPAnimEncoder* enc = NULL;
+  WebPAnimEncoderOptions enc_options;
+  WebPConfig config;
+
+  int frame_number = 0;     // Whether we are processing the first frame.
+  int done;
+  int c;
+  int quiet = 0;
+  WebPData webp_data;
+
+  int keep_metadata = METADATA_XMP;  // ICC not output by default.
+  WebPData icc_data;
+  int stored_icc = 0;         // Whether we have already stored an ICC profile.
+  WebPData xmp_data;
+  int stored_xmp = 0;         // Whether we have already stored an XMP profile.
+  int loop_count = 0;         // default: infinite
+  int stored_loop_count = 0;  // Whether we have found an explicit loop count.
+  int loop_compatibility = 0;
+  WebPMux* mux = NULL;
+
+  int default_kmin = 1;  // Whether to use default kmin value.
+  int default_kmax = 1;
+
+  INIT_WARGV(argc, argv);
+
+  if (!WebPConfigInit(&config) || !WebPAnimEncoderOptionsInit(&enc_options) ||
+      !WebPPictureInit(&frame) || !WebPPictureInit(&curr_canvas) ||
+      !WebPPictureInit(&prev_canvas)) {
+    fprintf(stderr, "Error! Version mismatch!\n");
+    FREE_WARGV_AND_RETURN(-1);
+  }
+  config.lossless = 1;  // Use lossless compression by default.
+
+  WebPDataInit(&webp_data);
+  WebPDataInit(&icc_data);
+  WebPDataInit(&xmp_data);
+
+  if (argc == 1) {
+    Help();
+    FREE_WARGV_AND_RETURN(0);
+  }
+
+  for (c = 1; c < argc; ++c) {
+    int parse_error = 0;
+    if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
+      Help();
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-o") && c < argc - 1) {
+      out_file = GET_WARGV(argv, ++c);
+    } else if (!strcmp(argv[c], "-lossy")) {
+      config.lossless = 0;
+    } else if (!strcmp(argv[c], "-mixed")) {
+      enc_options.allow_mixed = 1;
+      config.lossless = 0;
+    } else if (!strcmp(argv[c], "-loop_compatibility")) {
+      loop_compatibility = 1;
+    } else if (!strcmp(argv[c], "-q") && c < argc - 1) {
+      config.quality = ExUtilGetFloat(argv[++c], &parse_error);
+    } else if (!strcmp(argv[c], "-m") && c < argc - 1) {
+      config.method = ExUtilGetInt(argv[++c], 0, &parse_error);
+    } else if (!strcmp(argv[c], "-min_size")) {
+      enc_options.minimize_size = 1;
+    } else if (!strcmp(argv[c], "-kmax") && c < argc - 1) {
+      enc_options.kmax = ExUtilGetInt(argv[++c], 0, &parse_error);
+      default_kmax = 0;
+    } else if (!strcmp(argv[c], "-kmin") && c < argc - 1) {
+      enc_options.kmin = ExUtilGetInt(argv[++c], 0, &parse_error);
+      default_kmin = 0;
+    } else if (!strcmp(argv[c], "-f") && c < argc - 1) {
+      config.filter_strength = ExUtilGetInt(argv[++c], 0, &parse_error);
+    } else if (!strcmp(argv[c], "-metadata") && c < argc - 1) {
+      static const struct {
+        const char* option;
+        int flag;
+      } kTokens[] = {
+        { "all",  METADATA_ALL },
+        { "none", 0 },
+        { "icc",  METADATA_ICC },
+        { "xmp",  METADATA_XMP },
+      };
+      const size_t kNumTokens = sizeof(kTokens) / sizeof(*kTokens);
+      const char* start = argv[++c];
+      const char* const end = start + strlen(start);
+
+      keep_metadata = 0;
+      while (start < end) {
+        size_t i;
+        const char* token = strchr(start, ',');
+        if (token == NULL) token = end;
+
+        for (i = 0; i < kNumTokens; ++i) {
+          if ((size_t)(token - start) == strlen(kTokens[i].option) &&
+              !strncmp(start, kTokens[i].option, strlen(kTokens[i].option))) {
+            if (kTokens[i].flag != 0) {
+              keep_metadata |= kTokens[i].flag;
+            } else {
+              keep_metadata = 0;
+            }
+            break;
+          }
+        }
+        if (i == kNumTokens) {
+          fprintf(stderr, "Error! Unknown metadata type '%.*s'\n",
+                  (int)(token - start), start);
+          Help();
+          FREE_WARGV_AND_RETURN(-1);
+        }
+        start = token + 1;
+      }
+    } else if (!strcmp(argv[c], "-mt")) {
+      ++config.thread_level;
+    } else if (!strcmp(argv[c], "-version")) {
+      const int enc_version = WebPGetEncoderVersion();
+      const int mux_version = WebPGetMuxVersion();
+      printf("WebP Encoder version: %d.%d.%d\nWebP Mux version: %d.%d.%d\n",
+             (enc_version >> 16) & 0xff, (enc_version >> 8) & 0xff,
+             enc_version & 0xff, (mux_version >> 16) & 0xff,
+             (mux_version >> 8) & 0xff, mux_version & 0xff);
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-quiet")) {
+      quiet = 1;
+      enc_options.verbose = 0;
+    } else if (!strcmp(argv[c], "-v")) {
+      verbose = 1;
+      enc_options.verbose = 1;
+    } else if (!strcmp(argv[c], "--")) {
+      if (c < argc - 1) in_file = GET_WARGV(argv, ++c);
+      break;
+    } else if (argv[c][0] == '-') {
+      fprintf(stderr, "Error! Unknown option '%s'\n", argv[c]);
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    } else {
+      in_file = GET_WARGV(argv, c);
+    }
+
+    if (parse_error) {
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    }
+  }
+
+  // Appropriate default kmin, kmax values for lossy and lossless.
+  if (default_kmin) {
+    enc_options.kmin = config.lossless ? 9 : 3;
+  }
+  if (default_kmax) {
+    enc_options.kmax = config.lossless ? 17 : 5;
+  }
+
+  if (!WebPValidateConfig(&config)) {
+    fprintf(stderr, "Error! Invalid configuration.\n");
+    goto End;
+  }
+
+  if (in_file == NULL) {
+    fprintf(stderr, "No input file specified!\n");
+    Help();
+    goto End;
+  }
+
+  // Start the decoder object
+  gif = DGifOpenFileUnicode(in_file, &gif_error);
+  if (gif == NULL) goto End;
+
+  // Loop over GIF images
+  done = 0;
+  do {
+    GifRecordType type;
+    if (DGifGetRecordType(gif, &type) == GIF_ERROR) goto End;
+
+    switch (type) {
+      case IMAGE_DESC_RECORD_TYPE: {
+        GIFFrameRect gif_rect;
+        GifImageDesc* const image_desc = &gif->Image;
+
+        if (!DGifGetImageDesc(gif)) goto End;
+
+        if (frame_number == 0) {
+          if (verbose) {
+            printf("Canvas screen: %d x %d\n", gif->SWidth, gif->SHeight);
+          }
+          // Fix some broken GIF global headers that report
+          // 0 x 0 screen dimension.
+          if (gif->SWidth == 0 || gif->SHeight == 0) {
+            image_desc->Left = 0;
+            image_desc->Top = 0;
+            gif->SWidth = image_desc->Width;
+            gif->SHeight = image_desc->Height;
+            if (gif->SWidth <= 0 || gif->SHeight <= 0) {
+              goto End;
+            }
+            if (verbose) {
+              printf("Fixed canvas screen dimension to: %d x %d\n",
+                     gif->SWidth, gif->SHeight);
+            }
+          }
+          // Allocate current buffer.
+          frame.width = gif->SWidth;
+          frame.height = gif->SHeight;
+          frame.use_argb = 1;
+          if (!WebPPictureAlloc(&frame)) goto End;
+          GIFClearPic(&frame, NULL);
+          if (!(WebPPictureCopy(&frame, &curr_canvas) &&
+                WebPPictureCopy(&frame, &prev_canvas))) {
+            fprintf(stderr, "Error allocating canvas.\n");
+            goto End;
+          }
+
+          // Background color.
+          GIFGetBackgroundColor(gif->SColorMap, gif->SBackGroundColor,
+                                transparent_index,
+                                &enc_options.anim_params.bgcolor);
+
+          // Initialize encoder.
+          enc = WebPAnimEncoderNew(curr_canvas.width, curr_canvas.height,
+                                   &enc_options);
+          if (enc == NULL) {
+            fprintf(stderr,
+                    "Error! Could not create encoder object. Possibly due to "
+                    "a memory error.\n");
+            goto End;
+          }
+        }
+
+        // Some even more broken GIF can have sub-rect with zero width/height.
+        if (image_desc->Width == 0 || image_desc->Height == 0) {
+          image_desc->Width = gif->SWidth;
+          image_desc->Height = gif->SHeight;
+        }
+
+        if (!GIFReadFrame(gif, transparent_index, &gif_rect, &frame)) {
+          goto End;
+        }
+        // Blend frame rectangle with previous canvas to compose full canvas.
+        // Note that 'curr_canvas' is same as 'prev_canvas' at this point.
+        GIFBlendFrames(&frame, &gif_rect, &curr_canvas);
+
+        if (!WebPAnimEncoderAdd(enc, &curr_canvas, frame_timestamp, &config)) {
+          fprintf(stderr, "Error while adding frame #%d: %s\n", frame_number,
+                  WebPAnimEncoderGetError(enc));
+          goto End;
+        } else {
+          ++frame_number;
+        }
+
+        // Update canvases.
+        GIFDisposeFrame(orig_dispose, &gif_rect, &prev_canvas, &curr_canvas);
+        GIFCopyPixels(&curr_canvas, &prev_canvas);
+
+        // Force frames with a small or no duration to 100ms to be consistent
+        // with web browsers and other transcoding tools. This also avoids
+        // incorrect durations between frames when padding frames are
+        // discarded.
+        if (frame_duration <= 10) {
+          frame_duration = 100;
+        }
+
+        // Update timestamp (for next frame).
+        frame_timestamp += frame_duration;
+
+        // In GIF, graphic control extensions are optional for a frame, so we
+        // may not get one before reading the next frame. To handle this case,
+        // we reset frame properties to reasonable defaults for the next frame.
+        orig_dispose = GIF_DISPOSE_NONE;
+        frame_duration = 0;
+        transparent_index = GIF_INDEX_INVALID;
+        break;
+      }
+      case EXTENSION_RECORD_TYPE: {
+        int extension;
+        GifByteType* data = NULL;
+        if (DGifGetExtension(gif, &extension, &data) == GIF_ERROR) {
+          goto End;
+        }
+        if (data == NULL) continue;
+
+        switch (extension) {
+          case COMMENT_EXT_FUNC_CODE: {
+            break;  // Do nothing for now.
+          }
+          case GRAPHICS_EXT_FUNC_CODE: {
+            if (!GIFReadGraphicsExtension(data, &frame_duration, &orig_dispose,
+                                          &transparent_index)) {
+              goto End;
+            }
+            break;
+          }
+          case PLAINTEXT_EXT_FUNC_CODE: {
+            break;
+          }
+          case APPLICATION_EXT_FUNC_CODE: {
+            if (data[0] != 11) break;    // Chunk is too short
+            if (!memcmp(data + 1, "NETSCAPE2.0", 11) ||
+                !memcmp(data + 1, "ANIMEXTS1.0", 11)) {
+              if (!GIFReadLoopCount(gif, &data, &loop_count)) {
+                goto End;
+              }
+              if (verbose) {
+                fprintf(stderr, "Loop count: %d\n", loop_count);
+              }
+              stored_loop_count = loop_compatibility ? (loop_count != 0) : 1;
+            } else {  // An extension containing metadata.
+              // We only store the first encountered chunk of each type, and
+              // only if requested by the user.
+              const int is_xmp = (keep_metadata & METADATA_XMP) &&
+                                 !stored_xmp &&
+                                 !memcmp(data + 1, "XMP DataXMP", 11);
+              const int is_icc = (keep_metadata & METADATA_ICC) &&
+                                 !stored_icc &&
+                                 !memcmp(data + 1, "ICCRGBG1012", 11);
+              if (is_xmp || is_icc) {
+                if (!GIFReadMetadata(gif, &data,
+                                     is_xmp ? &xmp_data : &icc_data)) {
+                  goto End;
+                }
+                if (is_icc) {
+                  stored_icc = 1;
+                } else if (is_xmp) {
+                  stored_xmp = 1;
+                }
+              }
+            }
+            break;
+          }
+          default: {
+            break;  // skip
+          }
+        }
+        while (data != NULL) {
+          if (DGifGetExtensionNext(gif, &data) == GIF_ERROR) goto End;
+        }
+        break;
+      }
+      case TERMINATE_RECORD_TYPE: {
+        done = 1;
+        break;
+      }
+      default: {
+        if (verbose) {
+          fprintf(stderr, "Skipping over unknown record type %d\n", type);
+        }
+        break;
+      }
+    }
+  } while (!done);
+
+  // Last NULL frame.
+  if (!WebPAnimEncoderAdd(enc, NULL, frame_timestamp, NULL)) {
+    fprintf(stderr, "Error flushing WebP muxer.\n");
+    fprintf(stderr, "%s\n", WebPAnimEncoderGetError(enc));
+  }
+
+  if (!WebPAnimEncoderAssemble(enc, &webp_data)) {
+    fprintf(stderr, "%s\n", WebPAnimEncoderGetError(enc));
+    goto End;
+  }
+  // If there's only one frame, we don't need to handle loop count.
+  if (frame_number == 1) {
+    loop_count = 0;
+  } else if (!loop_compatibility) {
+    if (!stored_loop_count) {
+      // if no loop-count element is seen, the default is '1' (loop-once)
+      // and we need to signal it explicitly in WebP. Note however that
+      // in case there's a single frame, we still don't need to store it.
+      if (frame_number > 1) {
+        stored_loop_count = 1;
+        loop_count = 1;
+      }
+    } else if (loop_count > 0 && loop_count < 65535) {
+      // adapt GIF's semantic to WebP's (except in the infinite-loop case)
+      loop_count += 1;
+    }
+  }
+  // loop_count of 0 is the default (infinite), so no need to signal it
+  if (loop_count == 0) stored_loop_count = 0;
+
+  if (stored_loop_count || stored_icc || stored_xmp) {
+    // Re-mux to add loop count and/or metadata as needed.
+    mux = WebPMuxCreate(&webp_data, 1);
+    if (mux == NULL) {
+      fprintf(stderr, "ERROR: Could not re-mux to add loop count/metadata.\n");
+      goto End;
+    }
+    WebPDataClear(&webp_data);
+
+    if (stored_loop_count) {  // Update loop count.
+      WebPMuxAnimParams new_params;
+      err = WebPMuxGetAnimationParams(mux, &new_params);
+      if (err != WEBP_MUX_OK) {
+        fprintf(stderr, "ERROR (%s): Could not fetch loop count.\n",
+                ErrorString(err));
+        goto End;
+      }
+      new_params.loop_count = loop_count;
+      err = WebPMuxSetAnimationParams(mux, &new_params);
+      if (err != WEBP_MUX_OK) {
+        fprintf(stderr, "ERROR (%s): Could not update loop count.\n",
+                ErrorString(err));
+        goto End;
+      }
+    }
+
+    if (stored_icc) {   // Add ICCP chunk.
+      err = WebPMuxSetChunk(mux, "ICCP", &icc_data, 1);
+      if (verbose) {
+        fprintf(stderr, "ICC size: %d\n", (int)icc_data.size);
+      }
+      if (err != WEBP_MUX_OK) {
+        fprintf(stderr, "ERROR (%s): Could not set ICC chunk.\n",
+                ErrorString(err));
+        goto End;
+      }
+    }
+
+    if (stored_xmp) {   // Add XMP chunk.
+      err = WebPMuxSetChunk(mux, "XMP ", &xmp_data, 1);
+      if (verbose) {
+        fprintf(stderr, "XMP size: %d\n", (int)xmp_data.size);
+      }
+      if (err != WEBP_MUX_OK) {
+        fprintf(stderr, "ERROR (%s): Could not set XMP chunk.\n",
+                ErrorString(err));
+        goto End;
+      }
+    }
+
+    err = WebPMuxAssemble(mux, &webp_data);
+    if (err != WEBP_MUX_OK) {
+      fprintf(stderr, "ERROR (%s): Could not assemble when re-muxing to add "
+              "loop count/metadata.\n", ErrorString(err));
+      goto End;
+    }
+  }
+
+  if (out_file != NULL) {
+    if (!ImgIoUtilWriteFile((const char*)out_file, webp_data.bytes,
+                            webp_data.size)) {
+      WFPRINTF(stderr, "Error writing output file: %s\n", out_file);
+      goto End;
+    }
+    if (!quiet) {
+      if (!WSTRCMP(out_file, "-")) {
+        fprintf(stderr, "Saved %d bytes to STDIO\n",
+                (int)webp_data.size);
+      } else {
+        WFPRINTF(stderr, "Saved output file (%d bytes): %s\n",
+                 (int)webp_data.size, out_file);
+      }
+    }
+  } else {
+    if (!quiet) {
+      fprintf(stderr, "Nothing written; use -o flag to save the result "
+                      "(%d bytes).\n", (int)webp_data.size);
+    }
+  }
+
+  // All OK.
+  ok = 1;
+  gif_error = GIF_OK;
+
+ End:
+  WebPDataClear(&icc_data);
+  WebPDataClear(&xmp_data);
+  WebPMuxDelete(mux);
+  WebPDataClear(&webp_data);
+  WebPPictureFree(&frame);
+  WebPPictureFree(&curr_canvas);
+  WebPPictureFree(&prev_canvas);
+  WebPAnimEncoderDelete(enc);
+
+  if (gif_error != GIF_OK) {
+    GIFDisplayError(gif, gif_error);
+  }
+  if (gif != NULL) {
+#if LOCAL_GIF_PREREQ(5,1)
+    DGifCloseFile(gif, &gif_error);
+#else
+    DGifCloseFile(gif);
+#endif
+  }
+
+  FREE_WARGV_AND_RETURN(!ok);
+}
+
+#else  // !WEBP_HAVE_GIF
+
+int main(int argc, const char* argv[]) {
+  fprintf(stderr, "GIF support not enabled in %s.\n", argv[0]);
+  (void)argc;
+  return 0;
+}
+
+#endif
+
+//------------------------------------------------------------------------------
--- a/external/libwebp/libwebp/examples/gifdec.c
+++ b/external/libwebp/libwebp/examples/gifdec.c
@@ -0,0 +1,416 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// GIF decode.
+
+#include "./gifdec.h"
+
+#include <stdio.h>
+
+#ifdef WEBP_HAVE_GIF
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/encode.h"
+#include "webp/mux_types.h"
+
+#define GIF_TRANSPARENT_COLOR 0x00000000u
+#define GIF_WHITE_COLOR       0xffffffffu
+#define GIF_TRANSPARENT_MASK  0x01
+#define GIF_DISPOSE_MASK      0x07
+#define GIF_DISPOSE_SHIFT     2
+
+// from utils/utils.h
+#ifdef __cplusplus
+extern "C" {
+#endif
+extern void WebPCopyPlane(const uint8_t* src, int src_stride,
+                          uint8_t* dst, int dst_stride,
+                          int width, int height);
+extern void WebPCopyPixels(const WebPPicture* const src,
+                           WebPPicture* const dst);
+#ifdef __cplusplus
+}
+#endif
+
+void GIFGetBackgroundColor(const ColorMapObject* const color_map,
+                           int bgcolor_index, int transparent_index,
+                           uint32_t* const bgcolor) {
+  if (transparent_index != GIF_INDEX_INVALID &&
+      bgcolor_index == transparent_index) {
+    *bgcolor = GIF_TRANSPARENT_COLOR;  // Special case.
+  } else if (color_map == NULL || color_map->Colors == NULL
+             || bgcolor_index >= color_map->ColorCount) {
+    *bgcolor = GIF_WHITE_COLOR;
+    fprintf(stderr,
+            "GIF decode warning: invalid background color index. Assuming "
+            "white background.\n");
+  } else {
+    const GifColorType color = color_map->Colors[bgcolor_index];
+    *bgcolor = (0xffu       << 24)
+             | (color.Red   << 16)
+             | (color.Green <<  8)
+             | (color.Blue  <<  0);
+  }
+}
+
+int GIFReadGraphicsExtension(const GifByteType* const buf, int* const duration,
+                             GIFDisposeMethod* const dispose,
+                             int* const transparent_index) {
+  const int flags = buf[1];
+  const int dispose_raw = (flags >> GIF_DISPOSE_SHIFT) & GIF_DISPOSE_MASK;
+  const int duration_raw = buf[2] | (buf[3] << 8);  // In 10 ms units.
+  if (buf[0] != 4) return 0;
+  *duration = duration_raw * 10;  // Duration is in 1 ms units.
+  switch (dispose_raw) {
+    case 3:
+      *dispose = GIF_DISPOSE_RESTORE_PREVIOUS;
+      break;
+    case 2:
+      *dispose = GIF_DISPOSE_BACKGROUND;
+      break;
+    case 1:
+    case 0:
+    default:
+      *dispose = GIF_DISPOSE_NONE;
+      break;
+  }
+  *transparent_index =
+      (flags & GIF_TRANSPARENT_MASK) ? buf[4] : GIF_INDEX_INVALID;
+  return 1;
+}
+
+static int Remap(const GifFileType* const gif, const uint8_t* const src,
+                 int len, int transparent_index, uint32_t* dst) {
+  int i;
+  const GifColorType* colors;
+  const ColorMapObject* const cmap =
+      gif->Image.ColorMap ? gif->Image.ColorMap : gif->SColorMap;
+  if (cmap == NULL) return 1;
+  if (cmap->Colors == NULL || cmap->ColorCount <= 0) return 0;
+  colors = cmap->Colors;
+
+  for (i = 0; i < len; ++i) {
+    if (src[i] == transparent_index) {
+      dst[i] = GIF_TRANSPARENT_COLOR;
+    } else if (src[i] < cmap->ColorCount) {
+      const GifColorType c = colors[src[i]];
+      dst[i] = c.Blue | (c.Green << 8) | (c.Red << 16) | (0xffu << 24);
+    } else {
+      return 0;
+    }
+  }
+  return 1;
+}
+
+int GIFReadFrame(GifFileType* const gif, int transparent_index,
+                 GIFFrameRect* const gif_rect, WebPPicture* const picture) {
+  WebPPicture sub_image;
+  const GifImageDesc* const image_desc = &gif->Image;
+  uint32_t* dst = NULL;
+  uint8_t* tmp = NULL;
+  const GIFFrameRect rect = {
+      image_desc->Left, image_desc->Top, image_desc->Width, image_desc->Height
+  };
+  const uint64_t memory_needed = 4 * rect.width * (uint64_t)rect.height;
+  int ok = 0;
+  *gif_rect = rect;
+
+  if (memory_needed != (size_t)memory_needed || memory_needed > (4ULL << 32)) {
+    fprintf(stderr, "Image is too large (%d x %d).", rect.width, rect.height);
+    return 0;
+  }
+
+  // Use a view for the sub-picture:
+  if (!WebPPictureView(picture, rect.x_offset, rect.y_offset,
+                       rect.width, rect.height, &sub_image)) {
+    fprintf(stderr, "Sub-image %dx%d at position %d,%d is invalid!\n",
+            rect.width, rect.height, rect.x_offset, rect.y_offset);
+    return 0;
+  }
+  dst = sub_image.argb;
+
+  tmp = (uint8_t*)WebPMalloc(rect.width * sizeof(*tmp));
+  if (tmp == NULL) goto End;
+
+  if (image_desc->Interlace) {  // Interlaced image.
+    // We need 4 passes, with the following offsets and jumps.
+    const int interlace_offsets[] = { 0, 4, 2, 1 };
+    const int interlace_jumps[]   = { 8, 8, 4, 2 };
+    int pass;
+    for (pass = 0; pass < 4; ++pass) {
+      const size_t stride = (size_t)sub_image.argb_stride;
+      int y = interlace_offsets[pass];
+      uint32_t* row = dst + y * stride;
+      const size_t jump = interlace_jumps[pass] * stride;
+      for (; y < rect.height; y += interlace_jumps[pass], row += jump) {
+        if (DGifGetLine(gif, tmp, rect.width) == GIF_ERROR) goto End;
+        if (!Remap(gif, tmp, rect.width, transparent_index, row)) goto End;
+      }
+    }
+  } else {  // Non-interlaced image.
+    int y;
+    uint32_t* ptr = dst;
+    for (y = 0; y < rect.height; ++y, ptr += sub_image.argb_stride) {
+      if (DGifGetLine(gif, tmp, rect.width) == GIF_ERROR) goto End;
+      if (!Remap(gif, tmp, rect.width, transparent_index, ptr)) goto End;
+    }
+  }
+  ok = 1;
+
+ End:
+  if (!ok) picture->error_code = sub_image.error_code;
+  WebPPictureFree(&sub_image);
+  WebPFree(tmp);
+  return ok;
+}
+
+int GIFReadLoopCount(GifFileType* const gif, GifByteType** const buf,
+                     int* const loop_count) {
+  assert(!memcmp(*buf + 1, "NETSCAPE2.0", 11) ||
+         !memcmp(*buf + 1, "ANIMEXTS1.0", 11));
+  if (DGifGetExtensionNext(gif, buf) == GIF_ERROR) {
+    return 0;
+  }
+  if (*buf == NULL) {
+    return 0;  // Loop count sub-block missing.
+  }
+  if ((*buf)[0] < 3 || (*buf)[1] != 1) {
+    return 0;   // wrong size/marker
+  }
+  *loop_count = (*buf)[2] | ((*buf)[3] << 8);
+  return 1;
+}
+
+int GIFReadMetadata(GifFileType* const gif, GifByteType** const buf,
+                    WebPData* const metadata) {
+  const int is_xmp = !memcmp(*buf + 1, "XMP DataXMP", 11);
+  const int is_icc = !memcmp(*buf + 1, "ICCRGBG1012", 11);
+  assert(is_xmp || is_icc);
+  (void)is_icc;  // silence unused warning.
+  // Construct metadata from sub-blocks.
+  // Usual case (including ICC profile): In each sub-block, the
+  // first byte specifies its size in bytes (0 to 255) and the
+  // rest of the bytes contain the data.
+  // Special case for XMP data: In each sub-block, the first byte
+  // is also part of the XMP payload. XMP in GIF also has a 257
+  // byte padding data. See the XMP specification for details.
+  while (1) {
+    WebPData subblock;
+    const uint8_t* tmp;
+    if (DGifGetExtensionNext(gif, buf) == GIF_ERROR) {
+      return 0;
+    }
+    if (*buf == NULL) break;  // Finished.
+    subblock.size = is_xmp ? (*buf)[0] + 1 : (*buf)[0];
+    assert(subblock.size > 0);
+    subblock.bytes = is_xmp ? *buf : *buf + 1;
+    // Note: We store returned value in 'tmp' first, to avoid
+    // leaking old memory in metadata->bytes on error.
+    tmp = (uint8_t*)realloc((void*)metadata->bytes,
+                            metadata->size + subblock.size);
+    if (tmp == NULL) {
+      return 0;
+    }
+    memcpy((void*)(tmp + metadata->size),
+           subblock.bytes, subblock.size);
+    metadata->bytes = tmp;
+    metadata->size += subblock.size;
+  }
+  if (is_xmp) {
+    // XMP padding data is 0x01, 0xff, 0xfe ... 0x01, 0x00.
+    const size_t xmp_pading_size = 257;
+    if (metadata->size > xmp_pading_size) {
+      metadata->size -= xmp_pading_size;
+    }
+  }
+  return 1;
+}
+
+static void ClearRectangle(WebPPicture* const picture,
+                           int left, int top, int width, int height) {
+  int i, j;
+  const size_t stride = picture->argb_stride;
+  uint32_t* dst = picture->argb + top * stride + left;
+  for (j = 0; j < height; ++j, dst += stride) {
+    for (i = 0; i < width; ++i) dst[i] = GIF_TRANSPARENT_COLOR;
+  }
+}
+
+void GIFClearPic(WebPPicture* const pic, const GIFFrameRect* const rect) {
+  if (rect != NULL) {
+    ClearRectangle(pic, rect->x_offset, rect->y_offset,
+                   rect->width, rect->height);
+  } else {
+    ClearRectangle(pic, 0, 0, pic->width, pic->height);
+  }
+}
+
+void GIFCopyPixels(const WebPPicture* const src, WebPPicture* const dst) {
+  WebPCopyPixels(src, dst);
+}
+
+void GIFDisposeFrame(GIFDisposeMethod dispose, const GIFFrameRect* const rect,
+                     const WebPPicture* const prev_canvas,
+                     WebPPicture* const curr_canvas) {
+  assert(rect != NULL);
+  if (dispose == GIF_DISPOSE_BACKGROUND) {
+    GIFClearPic(curr_canvas, rect);
+  } else if (dispose == GIF_DISPOSE_RESTORE_PREVIOUS) {
+    const size_t src_stride = prev_canvas->argb_stride;
+    const uint32_t* const src = prev_canvas->argb + rect->x_offset
+                              + rect->y_offset * src_stride;
+    const size_t dst_stride = curr_canvas->argb_stride;
+    uint32_t* const dst = curr_canvas->argb + rect->x_offset
+                        + rect->y_offset * dst_stride;
+    assert(prev_canvas != NULL);
+    WebPCopyPlane((uint8_t*)src, (int)(4 * src_stride),
+                  (uint8_t*)dst, (int)(4 * dst_stride),
+                  4 * rect->width, rect->height);
+  }
+}
+
+void GIFBlendFrames(const WebPPicture* const src,
+                    const GIFFrameRect* const rect, WebPPicture* const dst) {
+  int i, j;
+  const size_t src_stride = src->argb_stride;
+  const size_t dst_stride = dst->argb_stride;
+  assert(src->width == dst->width && src->height == dst->height);
+  for (j = rect->y_offset; j < rect->y_offset + rect->height; ++j) {
+    for (i = rect->x_offset; i < rect->x_offset + rect->width; ++i) {
+      const uint32_t src_pixel = src->argb[j * src_stride + i];
+      const int src_alpha = src_pixel >> 24;
+      if (src_alpha != 0) {
+        dst->argb[j * dst_stride + i] = src_pixel;
+      }
+    }
+  }
+}
+
+void GIFDisplayError(const GifFileType* const gif, int gif_error) {
+  // libgif 4.2.0 has retired PrintGifError() and added GifErrorString().
+#if LOCAL_GIF_PREREQ(4,2)
+#if LOCAL_GIF_PREREQ(5,0)
+  // Static string actually, hence the const char* cast.
+  const char* error_str = (const char*)GifErrorString(
+      (gif == NULL) ? gif_error : gif->Error);
+#else
+  const char* error_str = (const char*)GifErrorString();
+  (void)gif;
+#endif
+  if (error_str == NULL) error_str = "Unknown error";
+  fprintf(stderr, "GIFLib Error %d: %s\n", gif_error, error_str);
+#else
+  (void)gif;
+  fprintf(stderr, "GIFLib Error %d: ", gif_error);
+  PrintGifError();
+  fprintf(stderr, "\n");
+#endif
+}
+
+#else  // !WEBP_HAVE_GIF
+
+static void ErrorGIFNotAvailable() {
+  fprintf(stderr, "GIF support not compiled. Please install the libgif-dev "
+          "package before building.\n");
+}
+
+void GIFGetBackgroundColor(const struct ColorMapObject* const color_map,
+                           int bgcolor_index, int transparent_index,
+                           uint32_t* const bgcolor) {
+  (void)color_map;
+  (void)bgcolor_index;
+  (void)transparent_index;
+  (void)bgcolor;
+  ErrorGIFNotAvailable();
+}
+
+int GIFReadGraphicsExtension(const GifByteType* const data, int* const duration,
+                             GIFDisposeMethod* const dispose,
+                             int* const transparent_index) {
+  (void)data;
+  (void)duration;
+  (void)dispose;
+  (void)transparent_index;
+  ErrorGIFNotAvailable();
+  return 0;
+}
+
+int GIFReadFrame(struct GifFileType* const gif, int transparent_index,
+                 GIFFrameRect* const gif_rect,
+                 struct WebPPicture* const picture) {
+  (void)gif;
+  (void)transparent_index;
+  (void)gif_rect;
+  (void)picture;
+  ErrorGIFNotAvailable();
+  return 0;
+}
+
+int GIFReadLoopCount(struct GifFileType* const gif, GifByteType** const buf,
+                     int* const loop_count) {
+  (void)gif;
+  (void)buf;
+  (void)loop_count;
+  ErrorGIFNotAvailable();
+  return 0;
+}
+
+int GIFReadMetadata(struct GifFileType* const gif, GifByteType** const buf,
+                    struct WebPData* const metadata) {
+  (void)gif;
+  (void)buf;
+  (void)metadata;
+  ErrorGIFNotAvailable();
+  return 0;
+}
+
+void GIFDisposeFrame(GIFDisposeMethod dispose, const GIFFrameRect* const rect,
+                     const struct WebPPicture* const prev_canvas,
+                     struct WebPPicture* const curr_canvas) {
+  (void)dispose;
+  (void)rect;
+  (void)prev_canvas;
+  (void)curr_canvas;
+  ErrorGIFNotAvailable();
+}
+
+void GIFBlendFrames(const struct WebPPicture* const src,
+                    const GIFFrameRect* const rect,
+                    struct WebPPicture* const dst) {
+  (void)src;
+  (void)rect;
+  (void)dst;
+  ErrorGIFNotAvailable();
+}
+
+void GIFDisplayError(const struct GifFileType* const gif, int gif_error) {
+  (void)gif;
+  (void)gif_error;
+  ErrorGIFNotAvailable();
+}
+
+void GIFClearPic(struct WebPPicture* const pic,
+                 const GIFFrameRect* const rect) {
+  (void)pic;
+  (void)rect;
+  ErrorGIFNotAvailable();
+}
+
+void GIFCopyPixels(const struct WebPPicture* const src,
+                   struct WebPPicture* const dst) {
+  (void)src;
+  (void)dst;
+  ErrorGIFNotAvailable();
+}
+
+#endif  // WEBP_HAVE_GIF
+
+// -----------------------------------------------------------------------------
--- a/external/libwebp/libwebp/examples/gifdec.h
+++ b/external/libwebp/libwebp/examples/gifdec.h
@@ -0,0 +1,116 @@
+// Copyright 2014 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// GIF decode.
+
+#ifndef WEBP_EXAMPLES_GIFDEC_H_
+#define WEBP_EXAMPLES_GIFDEC_H_
+
+#include <stdio.h>
+#include "webp/types.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#ifdef WEBP_HAVE_GIF
+#include <gif_lib.h>
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// GIFLIB_MAJOR is only defined in libgif >= 4.2.0.
+#if defined(GIFLIB_MAJOR) && defined(GIFLIB_MINOR)
+# define LOCAL_GIF_VERSION ((GIFLIB_MAJOR << 8) | GIFLIB_MINOR)
+# define LOCAL_GIF_PREREQ(maj, min) \
+    (LOCAL_GIF_VERSION >= (((maj) << 8) | (min)))
+#else
+# define LOCAL_GIF_VERSION 0
+# define LOCAL_GIF_PREREQ(maj, min) 0
+#endif
+
+#define GIF_INDEX_INVALID (-1)
+
+typedef enum GIFDisposeMethod {
+  GIF_DISPOSE_NONE,
+  GIF_DISPOSE_BACKGROUND,
+  GIF_DISPOSE_RESTORE_PREVIOUS
+} GIFDisposeMethod;
+
+typedef struct {
+  int x_offset, y_offset, width, height;
+} GIFFrameRect;
+
+struct WebPData;
+struct WebPPicture;
+
+#ifndef WEBP_HAVE_GIF
+struct ColorMapObject;
+struct GifFileType;
+typedef unsigned char GifByteType;
+#endif
+
+// Given the index of background color and transparent color, returns the
+// corresponding background color (in BGRA format) in 'bgcolor'.
+void GIFGetBackgroundColor(const struct ColorMapObject* const color_map,
+                           int bgcolor_index, int transparent_index,
+                           uint32_t* const bgcolor);
+
+// Parses the given graphics extension data to get frame duration (in 1ms
+// units), dispose method and transparent color index.
+// Returns true on success.
+int GIFReadGraphicsExtension(const GifByteType* const buf, int* const duration,
+                             GIFDisposeMethod* const dispose,
+                             int* const transparent_index);
+
+// Reads the next GIF frame from 'gif' into 'picture'. Also, returns the GIF
+// frame dimensions and offsets in 'rect'.
+// Returns true on success.
+int GIFReadFrame(struct GifFileType* const gif, int transparent_index,
+                 GIFFrameRect* const gif_rect,
+                 struct WebPPicture* const picture);
+
+// Parses loop count from the given Netscape extension data.
+int GIFReadLoopCount(struct GifFileType* const gif, GifByteType** const buf,
+                     int* const loop_count);
+
+// Parses the given ICC or XMP extension data and stores it into 'metadata'.
+// Returns true on success.
+int GIFReadMetadata(struct GifFileType* const gif, GifByteType** const buf,
+                    struct WebPData* const metadata);
+
+// Dispose the pixels within 'rect' of 'curr_canvas' based on 'dispose' method
+// and 'prev_canvas'.
+void GIFDisposeFrame(GIFDisposeMethod dispose, const GIFFrameRect* const rect,
+                     const struct WebPPicture* const prev_canvas,
+                     struct WebPPicture* const curr_canvas);
+
+// Given 'src' picture and its frame rectangle 'rect', blend it into 'dst'.
+void GIFBlendFrames(const struct WebPPicture* const src,
+                    const GIFFrameRect* const rect,
+                    struct WebPPicture* const dst);
+
+// Prints an error string based on 'gif_error'.
+void GIFDisplayError(const struct GifFileType* const gif, int gif_error);
+
+// In the given 'pic', clear the pixels in 'rect' to transparent color.
+void GIFClearPic(struct WebPPicture* const pic, const GIFFrameRect* const rect);
+
+// Copy pixels from 'src' to 'dst' honoring strides. 'src' and 'dst' are assumed
+// to be already allocated.
+void GIFCopyPixels(const struct WebPPicture* const src,
+                   struct WebPPicture* const dst);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_EXAMPLES_GIFDEC_H_
--- a/external/libwebp/libwebp/examples/img2webp.c
+++ b/external/libwebp/libwebp/examples/img2webp.c
@@ -0,0 +1,339 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  generate an animated WebP out of a sequence of images
+//  (PNG, JPEG, ...)
+//
+//  Example usage:
+//     img2webp -o out.webp -q 40 -mixed -duration 40 input??.png
+//
+// Author: skal@google.com (Pascal Massimino)
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "../examples/example_util.h"
+#include "../imageio/image_dec.h"
+#include "../imageio/imageio_util.h"
+#include "./stopwatch.h"
+#include "./unicode.h"
+#include "sharpyuv/sharpyuv.h"
+#include "webp/encode.h"
+#include "webp/mux.h"
+
+//------------------------------------------------------------------------------
+
+static void Help(void) {
+  printf("Usage:\n\n");
+  printf("  img2webp [file_options] [[frame_options] frame_file]...");
+  printf(" [-o webp_file]\n\n");
+
+  printf("File-level options (only used at the start of compression):\n");
+  printf(" -min_size ............ minimize size\n");
+  printf(" -kmax <int> .......... maximum number of frame between key-frames\n"
+         "                        (0=only keyframes)\n");
+  printf(" -kmin <int> .......... minimum number of frame between key-frames\n"
+         "                        (0=disable key-frames altogether)\n");
+  printf(" -mixed ............... use mixed lossy/lossless automatic mode\n");
+  printf(" -near_lossless <int> . use near-lossless image preprocessing\n"
+         "                        (0..100=off), default=100\n");
+  printf(" -sharp_yuv ........... use sharper (and slower) RGB->YUV "
+                                  "conversion\n                        "
+                                  "(lossy only)\n");
+  printf(" -loop <int> .......... loop count (default: 0, = infinite loop)\n");
+  printf(" -v ................... verbose mode\n");
+  printf(" -h ................... this help\n");
+  printf(" -version ............. print version number and exit\n");
+  printf("\n");
+
+  printf("Per-frame options (only used for subsequent images input):\n");
+  printf(" -d <int> ............. frame duration in ms (default: 100)\n");
+  printf(" -lossless  ........... use lossless mode (default)\n");
+  printf(" -lossy ... ........... use lossy mode\n");
+  printf(" -q <float> ........... quality\n");
+  printf(" -m <int> ............. method to use\n");
+
+  printf("\n");
+  printf("example: img2webp -loop 2 in0.png -lossy in1.jpg\n"
+         "                  -d 80 in2.tiff -o out.webp\n");
+  printf("\nNote: if a single file name is passed as the argument, the "
+         "arguments will be\n");
+  printf("tokenized from this file. The file name must not start with "
+         "the character '-'.\n");
+  printf("\nSupported input formats:\n  %s\n",
+         WebPGetEnabledInputFileFormats());
+}
+
+//------------------------------------------------------------------------------
+
+static int ReadImage(const char filename[], WebPPicture* const pic) {
+  const uint8_t* data = NULL;
+  size_t data_size = 0;
+  WebPImageReader reader;
+  int ok;
+#ifdef HAVE_WINCODEC_H
+  // Try to decode the file using WIC falling back to the other readers for
+  // e.g., WebP.
+  ok = ReadPictureWithWIC(filename, pic, 1, NULL);
+  if (ok) return 1;
+#endif
+  if (!ImgIoUtilReadFile(filename, &data, &data_size)) return 0;
+  reader = WebPGuessImageReader(data, data_size);
+  ok = reader(data, data_size, pic, 1, NULL);
+  WebPFree((void*)data);
+  return ok;
+}
+
+static int SetLoopCount(int loop_count, WebPData* const webp_data) {
+  int ok = 1;
+  WebPMuxError err;
+  uint32_t features;
+  WebPMuxAnimParams new_params;
+  WebPMux* const mux = WebPMuxCreate(webp_data, 1);
+  if (mux == NULL) return 0;
+
+  err = WebPMuxGetFeatures(mux, &features);
+  ok = (err == WEBP_MUX_OK);
+  if (!ok || !(features & ANIMATION_FLAG)) goto End;
+
+  err = WebPMuxGetAnimationParams(mux, &new_params);
+  ok = (err == WEBP_MUX_OK);
+  if (ok) {
+    new_params.loop_count = loop_count;
+    err = WebPMuxSetAnimationParams(mux, &new_params);
+    ok = (err == WEBP_MUX_OK);
+  }
+  if (ok) {
+    WebPDataClear(webp_data);
+    err = WebPMuxAssemble(mux, webp_data);
+    ok = (err == WEBP_MUX_OK);
+  }
+
+ End:
+  WebPMuxDelete(mux);
+  if (!ok) {
+    fprintf(stderr, "Error during loop-count setting\n");
+  }
+  return ok;
+}
+
+//------------------------------------------------------------------------------
+
+int main(int argc, const char* argv[]) {
+  const char* output = NULL;
+  WebPAnimEncoder* enc = NULL;
+  int verbose = 0;
+  int pic_num = 0;
+  int duration = 100;
+  int timestamp_ms = 0;
+  int loop_count = 0;
+  int width = 0, height = 0;
+  WebPAnimEncoderOptions anim_config;
+  WebPConfig config;
+  WebPPicture pic;
+  WebPData webp_data;
+  int c;
+  int have_input = 0;
+  CommandLineArguments cmd_args;
+  int ok;
+
+  INIT_WARGV(argc, argv);
+
+  ok = ExUtilInitCommandLineArguments(argc - 1, argv + 1, &cmd_args);
+  if (!ok) FREE_WARGV_AND_RETURN(1);
+
+  argc = cmd_args.argc_;
+  argv = cmd_args.argv_;
+
+  WebPDataInit(&webp_data);
+  if (!WebPAnimEncoderOptionsInit(&anim_config) ||
+      !WebPConfigInit(&config) ||
+      !WebPPictureInit(&pic)) {
+    fprintf(stderr, "Library version mismatch!\n");
+    ok = 0;
+    goto End;
+  }
+
+  // 1st pass of option parsing
+  for (c = 0; ok && c < argc; ++c) {
+    if (argv[c][0] == '-') {
+      int parse_error = 0;
+      if (!strcmp(argv[c], "-o") && c + 1 < argc) {
+        argv[c] = NULL;
+        output = (const char*)GET_WARGV_SHIFTED(argv, ++c);
+      } else if (!strcmp(argv[c], "-kmin") && c + 1 < argc) {
+        argv[c] = NULL;
+        anim_config.kmin = ExUtilGetInt(argv[++c], 0, &parse_error);
+      } else if (!strcmp(argv[c], "-kmax") && c + 1 < argc) {
+        argv[c] = NULL;
+        anim_config.kmax = ExUtilGetInt(argv[++c], 0, &parse_error);
+      } else if (!strcmp(argv[c], "-loop") && c + 1 < argc) {
+        argv[c] = NULL;
+        loop_count = ExUtilGetInt(argv[++c], 0, &parse_error);
+        if (loop_count < 0) {
+          fprintf(stderr, "Invalid non-positive loop-count (%d)\n", loop_count);
+          parse_error = 1;
+        }
+      } else if (!strcmp(argv[c], "-min_size")) {
+        anim_config.minimize_size = 1;
+      } else if (!strcmp(argv[c], "-mixed")) {
+        anim_config.allow_mixed = 1;
+        config.lossless = 0;
+      } else if (!strcmp(argv[c], "-near_lossless") && c + 1 < argc) {
+        argv[c] = NULL;
+        config.near_lossless = ExUtilGetInt(argv[++c], 0, &parse_error);
+      } else if (!strcmp(argv[c], "-sharp_yuv")) {
+        config.use_sharp_yuv = 1;
+      } else if (!strcmp(argv[c], "-v")) {
+        verbose = 1;
+      } else if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
+        Help();
+        FREE_WARGV_AND_RETURN(0);
+      } else if (!strcmp(argv[c], "-version")) {
+        const int enc_version = WebPGetEncoderVersion();
+        const int mux_version = WebPGetMuxVersion();
+        const int sharpyuv_version = SharpYuvGetVersion();
+        printf("WebP Encoder version: %d.%d.%d\nWebP Mux version: %d.%d.%d\n",
+               (enc_version >> 16) & 0xff, (enc_version >> 8) & 0xff,
+               enc_version & 0xff, (mux_version >> 16) & 0xff,
+               (mux_version >> 8) & 0xff, mux_version & 0xff);
+        printf("libsharpyuv: %d.%d.%d\n", (sharpyuv_version >> 24) & 0xff,
+               (sharpyuv_version >> 16) & 0xffff, sharpyuv_version & 0xff);
+        goto End;
+      } else {
+        continue;
+      }
+      ok = !parse_error;
+      if (!ok) goto End;
+      argv[c] = NULL;   // mark option as 'parsed' during 1st pass
+    } else {
+      have_input |= 1;
+    }
+  }
+  if (!have_input) {
+    fprintf(stderr, "No input file(s) for generating animation!\n");
+    goto End;
+  }
+
+  // image-reading pass
+  pic_num = 0;
+  config.lossless = 1;
+  for (c = 0; ok && c < argc; ++c) {
+    if (argv[c] == NULL) continue;
+    if (argv[c][0] == '-') {    // parse local options
+      int parse_error = 0;
+      if (!strcmp(argv[c], "-lossy")) {
+        if (!anim_config.allow_mixed) config.lossless = 0;
+      } else if (!strcmp(argv[c], "-lossless")) {
+        if (!anim_config.allow_mixed) config.lossless = 1;
+      } else if (!strcmp(argv[c], "-q") && c + 1 < argc) {
+        config.quality = ExUtilGetFloat(argv[++c], &parse_error);
+      } else if (!strcmp(argv[c], "-m") && c + 1 < argc) {
+        config.method = ExUtilGetInt(argv[++c], 0, &parse_error);
+      } else if (!strcmp(argv[c], "-d") && c + 1 < argc) {
+        duration = ExUtilGetInt(argv[++c], 0, &parse_error);
+        if (duration <= 0) {
+          fprintf(stderr, "Invalid negative duration (%d)\n", duration);
+          parse_error = 1;
+        }
+      } else {
+        parse_error = 1;   // shouldn't be here.
+        fprintf(stderr, "Unknown option [%s]\n", argv[c]);
+      }
+      ok = !parse_error;
+      if (!ok) goto End;
+      continue;
+    }
+
+    if (ok) {
+      ok = WebPValidateConfig(&config);
+      if (!ok) {
+        fprintf(stderr, "Invalid configuration.\n");
+        goto End;
+      }
+    }
+
+    // read next input image
+    pic.use_argb = 1;
+    ok = ReadImage((const char*)GET_WARGV_SHIFTED(argv, c), &pic);
+    if (!ok) goto End;
+
+    if (enc == NULL) {
+      width  = pic.width;
+      height = pic.height;
+      enc = WebPAnimEncoderNew(width, height, &anim_config);
+      ok = (enc != NULL);
+      if (!ok) {
+        fprintf(stderr, "Could not create WebPAnimEncoder object.\n");
+      }
+    }
+
+    if (ok) {
+      ok = (width == pic.width && height == pic.height);
+      if (!ok) {
+        fprintf(stderr, "Frame #%d dimension mismatched! "
+                        "Got %d x %d. Was expecting %d x %d.\n",
+                pic_num, pic.width, pic.height, width, height);
+      }
+    }
+
+    if (ok) {
+      ok = WebPAnimEncoderAdd(enc, &pic, timestamp_ms, &config);
+      if (!ok) {
+        fprintf(stderr, "Error while adding frame #%d\n", pic_num);
+      }
+    }
+    WebPPictureFree(&pic);
+    if (!ok) goto End;
+
+    if (verbose) {
+      WFPRINTF(stderr, "Added frame #%3d at time %4d (file: %s)\n",
+               pic_num, timestamp_ms, GET_WARGV_SHIFTED(argv, c));
+    }
+    timestamp_ms += duration;
+    ++pic_num;
+  }
+
+  // add a last fake frame to signal the last duration
+  ok = ok && WebPAnimEncoderAdd(enc, NULL, timestamp_ms, NULL);
+  ok = ok && WebPAnimEncoderAssemble(enc, &webp_data);
+  if (!ok) {
+    fprintf(stderr, "Error during final animation assembly.\n");
+  }
+
+ End:
+  // free resources
+  WebPAnimEncoderDelete(enc);
+
+  if (ok && loop_count > 0) {  // Re-mux to add loop count.
+    ok = SetLoopCount(loop_count, &webp_data);
+  }
+
+  if (ok) {
+    if (output != NULL) {
+      ok = ImgIoUtilWriteFile(output, webp_data.bytes, webp_data.size);
+      if (ok) WFPRINTF(stderr, "output file: %s     ", (const W_CHAR*)output);
+    } else {
+      fprintf(stderr, "[no output file specified]   ");
+    }
+  }
+
+  if (ok) {
+    fprintf(stderr, "[%d frames, %u bytes].\n",
+            pic_num, (unsigned int)webp_data.size);
+  }
+  WebPDataClear(&webp_data);
+  ExUtilDeleteCommandLineArguments(&cmd_args);
+  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+}
--- a/external/libwebp/libwebp/examples/stopwatch.h
+++ b/external/libwebp/libwebp/examples/stopwatch.h
@@ -0,0 +1,63 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Helper functions to measure elapsed time.
+//
+// Author: Mikolaj Zalewski (mikolajz@google.com)
+
+#ifndef WEBP_EXAMPLES_STOPWATCH_H_
+#define WEBP_EXAMPLES_STOPWATCH_H_
+
+#include "webp/types.h"
+
+#if defined _WIN32 && !defined __GNUC__
+#include <windows.h>
+
+typedef LARGE_INTEGER Stopwatch;
+
+static WEBP_INLINE void StopwatchReset(Stopwatch* watch) {
+  QueryPerformanceCounter(watch);
+}
+
+static WEBP_INLINE double StopwatchReadAndReset(Stopwatch* watch) {
+  const LARGE_INTEGER old_value = *watch;
+  LARGE_INTEGER freq;
+  if (!QueryPerformanceCounter(watch))
+    return 0.0;
+  if (!QueryPerformanceFrequency(&freq))
+    return 0.0;
+  if (freq.QuadPart == 0)
+    return 0.0;
+  return (watch->QuadPart - old_value.QuadPart) / (double)freq.QuadPart;
+}
+
+
+#else    /* !_WIN32 */
+#include <string.h>  // memcpy
+#include <sys/time.h>
+
+typedef struct timeval Stopwatch;
+
+static WEBP_INLINE void StopwatchReset(Stopwatch* watch) {
+  gettimeofday(watch, NULL);
+}
+
+static WEBP_INLINE double StopwatchReadAndReset(Stopwatch* watch) {
+  struct timeval old_value;
+  double delta_sec, delta_usec;
+  memcpy(&old_value, watch, sizeof(old_value));
+  gettimeofday(watch, NULL);
+  delta_sec = (double)watch->tv_sec - old_value.tv_sec;
+  delta_usec = (double)watch->tv_usec - old_value.tv_usec;
+  return delta_sec + delta_usec / 1000000.0;
+}
+
+#endif   /* _WIN32 */
+
+#endif  // WEBP_EXAMPLES_STOPWATCH_H_
--- a/external/libwebp/libwebp/examples/test.webp
+++ b/external/libwebp/libwebp/examples/test.webp
--- a/external/libwebp/libwebp/examples/test_ref.ppm
+++ b/external/libwebp/libwebp/examples/test_ref.ppm
--- a/external/libwebp/libwebp/examples/unicode.h
+++ b/external/libwebp/libwebp/examples/unicode.h
@@ -0,0 +1,116 @@
+// Copyright 2018 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Unicode support for Windows. The main idea is to maintain an array of Unicode
+// arguments (wargv) and use it only for file paths. The regular argv is used
+// for everything else.
+//
+// Author: Yannis Guyon (yguyon@google.com)
+
+#ifndef WEBP_EXAMPLES_UNICODE_H_
+#define WEBP_EXAMPLES_UNICODE_H_
+
+#include <stdio.h>
+
+#if defined(_WIN32) && defined(_UNICODE)
+
+// wchar_t is used instead of TCHAR because we only perform additional work when
+// Unicode is enabled and because the output of CommandLineToArgvW() is wchar_t.
+
+#include <fcntl.h>
+#include <io.h>
+#include <wchar.h>
+#include <windows.h>
+#include <shellapi.h>
+
+// Create a wchar_t array containing Unicode parameters.
+#define INIT_WARGV(ARGC, ARGV)                                                \
+  int wargc;                                                                  \
+  const W_CHAR** const wargv =                                                \
+      (const W_CHAR**)CommandLineToArgvW(GetCommandLineW(), &wargc);          \
+  do {                                                                        \
+    if (wargv == NULL || wargc != (ARGC)) {                                   \
+      fprintf(stderr, "Error: Unable to get Unicode arguments.\n");           \
+      FREE_WARGV_AND_RETURN(-1);                                              \
+    }                                                                         \
+  } while (0)
+
+// Use this to get a Unicode argument (e.g. file path).
+#define GET_WARGV(UNUSED, C) wargv[C]
+// For cases where argv is shifted by one compared to wargv.
+#define GET_WARGV_SHIFTED(UNUSED, C) wargv[(C) + 1]
+#define GET_WARGV_OR_NULL() wargv
+
+// Release resources. LocalFree() is needed after CommandLineToArgvW().
+#define FREE_WARGV() LOCAL_FREE((W_CHAR** const)wargv)
+#define LOCAL_FREE(WARGV)                  \
+  do {                                     \
+    if ((WARGV) != NULL) LocalFree(WARGV); \
+  } while (0)
+
+#define W_CHAR wchar_t  // WCHAR without underscore might already be defined.
+#define TO_W_CHAR(STR) (L##STR)
+
+#define WFOPEN(ARG, OPT) _wfopen((const W_CHAR*)ARG, TO_W_CHAR(OPT))
+
+#define WFPRINTF(STREAM, STR, ...)                    \
+  do {                                                \
+    int prev_mode;                                    \
+    fflush(STREAM);                                   \
+    prev_mode = _setmode(_fileno(STREAM), _O_U8TEXT); \
+    fwprintf(STREAM, TO_W_CHAR(STR), __VA_ARGS__);    \
+    fflush(STREAM);                                   \
+    (void)_setmode(_fileno(STREAM), prev_mode);       \
+  } while (0)
+#define WPRINTF(STR, ...) WFPRINTF(stdout, STR, __VA_ARGS__)
+
+#define WSTRLEN(FILENAME) wcslen((const W_CHAR*)FILENAME)
+#define WSTRCMP(FILENAME, STR) wcscmp((const W_CHAR*)FILENAME, TO_W_CHAR(STR))
+#define WSTRRCHR(FILENAME, STR) wcsrchr((const W_CHAR*)FILENAME, TO_W_CHAR(STR))
+#define WSNPRINTF(A, B, STR, ...) _snwprintf(A, B, TO_W_CHAR(STR), __VA_ARGS__)
+
+#else
+
+#include <string.h>
+
+// Unicode file paths work as is on Unix platforms, and no extra work is done on
+// Windows either if Unicode is disabled.
+
+#define INIT_WARGV(ARGC, ARGV)
+
+#define GET_WARGV(ARGV, C) (ARGV)[C]
+#define GET_WARGV_SHIFTED(ARGV, C) (ARGV)[C]
+#define GET_WARGV_OR_NULL() NULL
+
+#define FREE_WARGV()
+#define LOCAL_FREE(WARGV)
+
+#define W_CHAR char
+#define TO_W_CHAR(STR) (STR)
+
+#define WFOPEN(ARG, OPT) fopen(ARG, OPT)
+
+#define WPRINTF(STR, ...) printf(STR, __VA_ARGS__)
+#define WFPRINTF(STREAM, STR, ...) fprintf(STREAM, STR, __VA_ARGS__)
+
+#define WSTRLEN(FILENAME) strlen(FILENAME)
+#define WSTRCMP(FILENAME, STR) strcmp(FILENAME, STR)
+#define WSTRRCHR(FILENAME, STR) strrchr(FILENAME, STR)
+#define WSNPRINTF(A, B, STR, ...) snprintf(A, B, STR, __VA_ARGS__)
+
+#endif  // defined(_WIN32) && defined(_UNICODE)
+
+// Don't forget to free wargv before returning (e.g. from main).
+#define FREE_WARGV_AND_RETURN(VALUE) \
+  do {                               \
+    FREE_WARGV();                    \
+    return (VALUE);                  \
+  } while (0)
+
+#endif  // WEBP_EXAMPLES_UNICODE_H_
--- a/external/libwebp/libwebp/examples/unicode_gif.h
+++ b/external/libwebp/libwebp/examples/unicode_gif.h
@@ -0,0 +1,76 @@
+// Copyright 2018 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// giflib doesn't have a Unicode DGifOpenFileName(). Let's make one.
+//
+// Author: Yannis Guyon (yguyon@google.com)
+
+#ifndef WEBP_EXAMPLES_UNICODE_GIF_H_
+#define WEBP_EXAMPLES_UNICODE_GIF_H_
+
+#include "./unicode.h"
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"  // For WEBP_HAVE_GIF
+#endif
+
+#if defined(WEBP_HAVE_GIF)
+
+#ifdef _WIN32
+#include <fcntl.h>  // Not standard, needed for _topen and flags.
+#include <io.h>
+#endif
+
+#include <gif_lib.h>
+#include <string.h>
+#include "./gifdec.h"
+
+#if !defined(STDIN_FILENO)
+#define STDIN_FILENO 0
+#endif
+
+static GifFileType* DGifOpenFileUnicode(const W_CHAR* file_name, int* error) {
+  if (!WSTRCMP(file_name, "-")) {
+#if LOCAL_GIF_PREREQ(5, 0)
+    return DGifOpenFileHandle(STDIN_FILENO, error);
+#else
+    (void)error;
+    return DGifOpenFileHandle(STDIN_FILENO);
+#endif
+  }
+
+#if defined(_WIN32) && defined(_UNICODE)
+  {
+    int file_handle = _wopen(file_name, _O_RDONLY | _O_BINARY);
+    if (file_handle == -1) {
+      if (error != NULL) *error = D_GIF_ERR_OPEN_FAILED;
+      return NULL;
+    }
+
+#if LOCAL_GIF_PREREQ(5, 0)
+    return DGifOpenFileHandle(file_handle, error);
+#else
+    return DGifOpenFileHandle(file_handle);
+#endif
+  }
+
+#else
+
+#if LOCAL_GIF_PREREQ(5, 0)
+  return DGifOpenFileName(file_name, error);
+#else
+  return DGifOpenFileName(file_name);
+#endif
+
+#endif  // defined(_WIN32) && defined(_UNICODE)
+  // DGifCloseFile() is called later.
+}
+
+#endif  // defined(WEBP_HAVE_GIF)
+
+#endif  // WEBP_EXAMPLES_UNICODE_GIF_H_
--- a/external/libwebp/libwebp/examples/vwebp.c
+++ b/external/libwebp/libwebp/examples/vwebp.c
@@ -0,0 +1,654 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Simple OpenGL-based WebP file viewer.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#if defined(__unix__) || defined(__CYGWIN__)
+#define _POSIX_C_SOURCE 200112L  // for setenv
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if defined(WEBP_HAVE_GL)
+
+#if defined(HAVE_GLUT_GLUT_H)
+#include <GLUT/glut.h>
+#else
+#include <GL/glut.h>
+#ifdef FREEGLUT
+#include <GL/freeglut.h>
+#endif
+#endif
+
+#ifdef WEBP_HAVE_QCMS
+#include <qcms.h>
+#endif
+
+#include "webp/decode.h"
+#include "webp/demux.h"
+
+#include "../examples/example_util.h"
+#include "../imageio/imageio_util.h"
+#include "./unicode.h"
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#define snprintf _snprintf
+#endif
+
+// Unfortunate global variables. Gathered into a struct for comfort.
+static struct {
+  int has_animation;
+  int has_color_profile;
+  int done;
+  int decoding_error;
+  int print_info;
+  int only_deltas;
+  int use_color_profile;
+  int draw_anim_background_color;
+
+  int canvas_width, canvas_height;
+  int loop_count;
+  uint32_t bg_color;
+
+  const char* file_name;
+  WebPData data;
+  WebPDecoderConfig config;
+  const WebPDecBuffer* pic;
+  WebPDemuxer* dmux;
+  WebPIterator curr_frame;
+  WebPIterator prev_frame;
+  WebPChunkIterator iccp;
+  int viewport_width, viewport_height;
+} kParams;
+
+static void ClearPreviousPic(void) {
+  WebPFreeDecBuffer((WebPDecBuffer*)kParams.pic);
+  kParams.pic = NULL;
+}
+
+static void ClearParams(void) {
+  ClearPreviousPic();
+  WebPDataClear(&kParams.data);
+  WebPDemuxReleaseIterator(&kParams.curr_frame);
+  WebPDemuxReleaseIterator(&kParams.prev_frame);
+  WebPDemuxReleaseChunkIterator(&kParams.iccp);
+  WebPDemuxDelete(kParams.dmux);
+  kParams.dmux = NULL;
+}
+
+// Sets the previous frame to the dimensions of the canvas and has it dispose
+// to background to cause the canvas to be cleared.
+static void ClearPreviousFrame(void) {
+  WebPIterator* const prev = &kParams.prev_frame;
+  prev->width = kParams.canvas_width;
+  prev->height = kParams.canvas_height;
+  prev->x_offset = prev->y_offset = 0;
+  prev->dispose_method = WEBP_MUX_DISPOSE_BACKGROUND;
+}
+
+// -----------------------------------------------------------------------------
+// Color profile handling
+static int ApplyColorProfile(const WebPData* const profile,
+                             WebPDecBuffer* const rgba) {
+#ifdef WEBP_HAVE_QCMS
+  int i, ok = 0;
+  uint8_t* line;
+  uint8_t major_revision;
+  qcms_profile* input_profile = NULL;
+  qcms_profile* output_profile = NULL;
+  qcms_transform* transform = NULL;
+  const qcms_data_type input_type = QCMS_DATA_RGBA_8;
+  const qcms_data_type output_type = QCMS_DATA_RGBA_8;
+  const qcms_intent intent = QCMS_INTENT_DEFAULT;
+
+  if (profile == NULL || rgba == NULL) return 0;
+  if (profile->bytes == NULL || profile->size < 10) return 1;
+  major_revision = profile->bytes[8];
+
+  qcms_enable_iccv4();
+  input_profile = qcms_profile_from_memory(profile->bytes, profile->size);
+  // qcms_profile_is_bogus() is broken with ICCv4.
+  if (input_profile == NULL ||
+      (major_revision < 4 && qcms_profile_is_bogus(input_profile))) {
+    fprintf(stderr, "Color profile is bogus!\n");
+    goto Error;
+  }
+
+  output_profile = qcms_profile_sRGB();
+  if (output_profile == NULL) {
+    fprintf(stderr, "Error creating output color profile!\n");
+    goto Error;
+  }
+
+  qcms_profile_precache_output_transform(output_profile);
+  transform = qcms_transform_create(input_profile, input_type,
+                                    output_profile, output_type,
+                                    intent);
+  if (transform == NULL) {
+    fprintf(stderr, "Error creating color transform!\n");
+    goto Error;
+  }
+
+  line = rgba->u.RGBA.rgba;
+  for (i = 0; i < rgba->height; ++i, line += rgba->u.RGBA.stride) {
+    qcms_transform_data(transform, line, line, rgba->width);
+  }
+  ok = 1;
+
+ Error:
+  if (input_profile != NULL) qcms_profile_release(input_profile);
+  if (output_profile != NULL) qcms_profile_release(output_profile);
+  if (transform != NULL) qcms_transform_release(transform);
+  return ok;
+#else
+  (void)profile;
+  (void)rgba;
+  return 1;
+#endif  // WEBP_HAVE_QCMS
+}
+
+//------------------------------------------------------------------------------
+// File decoding
+
+static int Decode(void) {   // Fills kParams.curr_frame
+  const WebPIterator* const curr = &kParams.curr_frame;
+  WebPDecoderConfig* const config = &kParams.config;
+  WebPDecBuffer* const output_buffer = &config->output;
+  int ok = 0;
+
+  ClearPreviousPic();
+  output_buffer->colorspace = MODE_RGBA;
+  ok = (WebPDecode(curr->fragment.bytes, curr->fragment.size,
+                   config) == VP8_STATUS_OK);
+  if (!ok) {
+    fprintf(stderr, "Decoding of frame #%d failed!\n", curr->frame_num);
+  } else {
+    kParams.pic = output_buffer;
+    if (kParams.use_color_profile) {
+      ok = ApplyColorProfile(&kParams.iccp.chunk, output_buffer);
+      if (!ok) {
+        fprintf(stderr, "Applying color profile to frame #%d failed!\n",
+                curr->frame_num);
+      }
+    }
+  }
+  return ok;
+}
+
+static void decode_callback(int what) {
+  if (what == 0 && !kParams.done) {
+    int duration = 0;
+    if (kParams.dmux != NULL) {
+      WebPIterator* const curr = &kParams.curr_frame;
+      if (!WebPDemuxNextFrame(curr)) {
+        WebPDemuxReleaseIterator(curr);
+        if (WebPDemuxGetFrame(kParams.dmux, 1, curr)) {
+          --kParams.loop_count;
+          kParams.done = (kParams.loop_count == 0);
+          if (kParams.done) return;
+          ClearPreviousFrame();
+        } else {
+          kParams.decoding_error = 1;
+          kParams.done = 1;
+          return;
+        }
+      }
+      duration = curr->duration;
+      // Behavior copied from Chrome, cf:
+      // https://cs.chromium.org/chromium/src/third_party/WebKit/Source/
+      // platform/graphics/DeferredImageDecoder.cpp?
+      // rcl=b4c33049f096cd283f32be9a58b9a9e768227c26&l=246
+      if (duration <= 10) duration = 100;
+    }
+    if (!Decode()) {
+      kParams.decoding_error = 1;
+      kParams.done = 1;
+    } else {
+      glutPostRedisplay();
+      glutTimerFunc(duration, decode_callback, what);
+    }
+  }
+}
+
+//------------------------------------------------------------------------------
+// Callbacks
+
+static void HandleKey(unsigned char key, int pos_x, int pos_y) {
+  // Note: rescaling the window or toggling some features during an animation
+  // generates visual artifacts. This is not fixed because refreshing the frame
+  // may require rendering the whole animation from start till current frame.
+  (void)pos_x;
+  (void)pos_y;
+  if (key == 'q' || key == 'Q' || key == 27 /* Esc */) {
+#ifdef FREEGLUT
+    glutLeaveMainLoop();
+#else
+    ClearParams();
+    exit(0);
+#endif
+  } else if (key == 'c') {
+    if (kParams.has_color_profile && !kParams.decoding_error) {
+      kParams.use_color_profile = 1 - kParams.use_color_profile;
+
+      if (kParams.has_animation) {
+        // Restart the completed animation to pickup the color profile change.
+        if (kParams.done && kParams.loop_count == 0) {
+          kParams.loop_count =
+              (int)WebPDemuxGetI(kParams.dmux, WEBP_FF_LOOP_COUNT) + 1;
+          kParams.done = 0;
+          // Start the decode loop immediately.
+          glutTimerFunc(0, decode_callback, 0);
+        }
+      } else {
+        Decode();
+        glutPostRedisplay();
+      }
+    }
+  } else if (key == 'b') {
+    kParams.draw_anim_background_color = 1 - kParams.draw_anim_background_color;
+    if (!kParams.has_animation) ClearPreviousFrame();
+    glutPostRedisplay();
+  } else if (key == 'i') {
+    kParams.print_info = 1 - kParams.print_info;
+    if (!kParams.has_animation) ClearPreviousFrame();
+    glutPostRedisplay();
+  } else if (key == 'd') {
+    kParams.only_deltas = 1 - kParams.only_deltas;
+    glutPostRedisplay();
+  }
+}
+
+static void HandleReshape(int width, int height) {
+  // Note: reshape doesn't preserve aspect ratio, and might
+  // be handling larger-than-screen pictures incorrectly.
+  glViewport(0, 0, width, height);
+  glMatrixMode(GL_PROJECTION);
+  glLoadIdentity();
+  glMatrixMode(GL_MODELVIEW);
+  glLoadIdentity();
+  kParams.viewport_width = width;
+  kParams.viewport_height = height;
+  if (!kParams.has_animation) ClearPreviousFrame();
+}
+
+static void PrintString(const char* const text) {
+  void* const font = GLUT_BITMAP_9_BY_15;
+  int i;
+  for (i = 0; text[i]; ++i) {
+    glutBitmapCharacter(font, text[i]);
+  }
+}
+
+static void PrintStringW(const char* const text) {
+#if defined(_WIN32) && defined(_UNICODE)
+  void* const font = GLUT_BITMAP_9_BY_15;
+  const W_CHAR* const wtext = (const W_CHAR*)text;
+  int i;
+  for (i = 0; wtext[i]; ++i) {
+    glutBitmapCharacter(font, wtext[i]);
+  }
+#else
+  PrintString(text);
+#endif
+}
+
+static float GetColorf(uint32_t color, int shift) {
+  return ((color >> shift) & 0xff) / 255.f;
+}
+
+static void DrawCheckerBoard(void) {
+  const int square_size = 8;  // must be a power of 2
+  int x, y;
+  GLint viewport[4];  // x, y, width, height
+
+  glPushMatrix();
+
+  glGetIntegerv(GL_VIEWPORT, viewport);
+  // shift to integer coordinates with (0,0) being top-left.
+  glOrtho(0, viewport[2], viewport[3], 0, -1, 1);
+  for (y = 0; y < viewport[3]; y += square_size) {
+    for (x = 0; x < viewport[2]; x += square_size) {
+      const GLubyte color = 128 + 64 * (!((x + y) & square_size));
+      glColor3ub(color, color, color);
+      glRecti(x, y, x + square_size, y + square_size);
+    }
+  }
+  glPopMatrix();
+}
+
+static void DrawBackground(void) {
+  // Whole window cleared with clear color, checkerboard rendered on top of it.
+  glClear(GL_COLOR_BUFFER_BIT);
+  DrawCheckerBoard();
+
+  // ANIM background color rendered (blend) on top. Default is white for still
+  // images (without ANIM chunk). glClear() can't be used for that (no blend).
+  if (kParams.draw_anim_background_color) {
+    glPushMatrix();
+    glLoadIdentity();
+    glColor4f(GetColorf(kParams.bg_color, 16),  // BGRA from spec
+              GetColorf(kParams.bg_color, 8),
+              GetColorf(kParams.bg_color, 0),
+              GetColorf(kParams.bg_color, 24));
+    glRecti(-1, -1, +1, +1);
+    glPopMatrix();
+  }
+}
+
+// Draw background in a scissored rectangle.
+static void DrawBackgroundScissored(int window_x, int window_y, int frame_w,
+                                    int frame_h) {
+  // Only update the requested area, not the whole canvas.
+  window_x = window_x * kParams.viewport_width / kParams.canvas_width;
+  window_y = window_y * kParams.viewport_height / kParams.canvas_height;
+  frame_w = frame_w * kParams.viewport_width / kParams.canvas_width;
+  frame_h = frame_h * kParams.viewport_height / kParams.canvas_height;
+
+  // glScissor() takes window coordinates (0,0 at bottom left).
+  window_y = kParams.viewport_height - window_y - frame_h;
+
+  glEnable(GL_SCISSOR_TEST);
+  glScissor(window_x, window_y, frame_w, frame_h);
+  DrawBackground();
+  glDisable(GL_SCISSOR_TEST);
+}
+
+static void HandleDisplay(void) {
+  const WebPDecBuffer* const pic = kParams.pic;
+  const WebPIterator* const curr = &kParams.curr_frame;
+  WebPIterator* const prev = &kParams.prev_frame;
+  GLfloat xoff, yoff;
+  if (pic == NULL) return;
+  glPushMatrix();
+  glPixelZoom((GLfloat)(+1. / kParams.canvas_width * kParams.viewport_width),
+              (GLfloat)(-1. / kParams.canvas_height * kParams.viewport_height));
+  xoff = (GLfloat)(2. * curr->x_offset / kParams.canvas_width);
+  yoff = (GLfloat)(2. * curr->y_offset / kParams.canvas_height);
+  glRasterPos2f(-1.f + xoff, 1.f - yoff);
+  glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+  glPixelStorei(GL_UNPACK_ROW_LENGTH, pic->u.RGBA.stride / 4);
+
+  if (kParams.only_deltas) {
+    DrawBackground();
+  } else {
+    // The rectangle of the previous frame might be different than the current
+    // frame, so we may need to DrawBackgroundScissored for both.
+    if (prev->dispose_method == WEBP_MUX_DISPOSE_BACKGROUND) {
+      // Clear the previous frame rectangle.
+      DrawBackgroundScissored(prev->x_offset, prev->y_offset, prev->width,
+                              prev->height);
+    }
+    if (curr->blend_method == WEBP_MUX_NO_BLEND) {
+      // We simulate no-blending behavior by first clearing the current frame
+      // rectangle and then alpha-blending against it.
+      DrawBackgroundScissored(curr->x_offset, curr->y_offset, curr->width,
+                              curr->height);
+    }
+  }
+
+  *prev = *curr;
+
+  glDrawPixels(pic->width, pic->height,
+               GL_RGBA, GL_UNSIGNED_BYTE,
+               (GLvoid*)pic->u.RGBA.rgba);
+  if (kParams.print_info) {
+    char tmp[32];
+
+    glColor4f(0.90f, 0.0f, 0.90f, 1.0f);
+    glRasterPos2f(-0.95f, 0.90f);
+    PrintStringW(kParams.file_name);
+
+    snprintf(tmp, sizeof(tmp), "Dimension:%d x %d", pic->width, pic->height);
+    glColor4f(0.90f, 0.0f, 0.90f, 1.0f);
+    glRasterPos2f(-0.95f, 0.80f);
+    PrintString(tmp);
+    if (curr->x_offset != 0 || curr->y_offset != 0) {
+      snprintf(tmp, sizeof(tmp), " (offset:%d,%d)",
+               curr->x_offset, curr->y_offset);
+      glRasterPos2f(-0.95f, 0.70f);
+      PrintString(tmp);
+    }
+  }
+  glPopMatrix();
+#if defined(__APPLE__) || defined(_WIN32)
+  glFlush();
+#else
+  glutSwapBuffers();
+#endif
+}
+
+static void StartDisplay(void) {
+  int width = kParams.canvas_width;
+  int height = kParams.canvas_height;
+  int screen_width, screen_height;
+  // TODO(webp:365) GLUT_DOUBLE results in flickering / old frames to be
+  // partially displayed with animated webp + alpha.
+#if defined(__APPLE__) || defined(_WIN32)
+  glutInitDisplayMode(GLUT_RGBA);
+#else
+  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
+#endif
+  screen_width = glutGet(GLUT_SCREEN_WIDTH);
+  screen_height = glutGet(GLUT_SCREEN_HEIGHT);
+  if (width > screen_width || height > screen_height) {
+    if (width > screen_width) {
+      height = (height * screen_width + width - 1) / width;
+      width = screen_width;
+    }
+    if (height > screen_height) {
+      width = (width * screen_height + height - 1) / height;
+      height = screen_height;
+    }
+  }
+  glutInitWindowSize(width, height);
+  glutCreateWindow("WebP viewer");
+  glutDisplayFunc(HandleDisplay);
+  glutReshapeFunc(HandleReshape);
+  glutIdleFunc(NULL);
+  glutKeyboardFunc(HandleKey);
+  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+  glEnable(GL_BLEND);
+  glClearColor(0, 0, 0, 0);  // window will be cleared to black (no blend)
+  DrawBackground();
+}
+
+//------------------------------------------------------------------------------
+// Main
+
+static void Help(void) {
+  printf(
+      "Usage: vwebp in_file [options]\n\n"
+      "Decodes the WebP image file and visualize it using OpenGL\n"
+      "Options are:\n"
+      "  -version ..... print version number and exit\n"
+      "  -noicc ....... don't use the icc profile if present\n"
+      "  -nofancy ..... don't use the fancy YUV420 upscaler\n"
+      "  -nofilter .... disable in-loop filtering\n"
+      "  -dither <int>  dithering strength (0..100), default=50\n"
+      "  -noalphadither disable alpha plane dithering\n"
+      "  -usebgcolor .. display background color\n"
+      "  -mt .......... use multi-threading\n"
+      "  -info ........ print info\n"
+      "  -h ........... this help message\n"
+      "\n"
+      "Keyboard shortcuts:\n"
+      "  'c' ................ toggle use of color profile\n"
+      "  'b' ................ toggle background color display\n"
+      "  'i' ................ overlay file information\n"
+      "  'd' ................ disable blending & disposal (debug)\n"
+      "  'q' / 'Q' / ESC .... quit\n");
+}
+
+int main(int argc, char* argv[]) {
+  int c;
+  WebPDecoderConfig* const config = &kParams.config;
+  WebPIterator* const curr = &kParams.curr_frame;
+
+  INIT_WARGV(argc, argv);
+
+  if (!WebPInitDecoderConfig(config)) {
+    fprintf(stderr, "Library version mismatch!\n");
+    FREE_WARGV_AND_RETURN(-1);
+  }
+  config->options.dithering_strength = 50;
+  config->options.alpha_dithering_strength = 100;
+  kParams.use_color_profile = 1;
+  // Background color hidden by default to see transparent areas.
+  kParams.draw_anim_background_color = 0;
+
+  for (c = 1; c < argc; ++c) {
+    int parse_error = 0;
+    if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
+      Help();
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-noicc")) {
+      kParams.use_color_profile = 0;
+    } else if (!strcmp(argv[c], "-nofancy")) {
+      config->options.no_fancy_upsampling = 1;
+    } else if (!strcmp(argv[c], "-nofilter")) {
+      config->options.bypass_filtering = 1;
+    } else if (!strcmp(argv[c], "-noalphadither")) {
+      config->options.alpha_dithering_strength = 0;
+    } else if (!strcmp(argv[c], "-usebgcolor")) {
+      kParams.draw_anim_background_color = 1;
+    } else if (!strcmp(argv[c], "-dither") && c + 1 < argc) {
+      config->options.dithering_strength =
+          ExUtilGetInt(argv[++c], 0, &parse_error);
+    } else if (!strcmp(argv[c], "-info")) {
+      kParams.print_info = 1;
+    } else if (!strcmp(argv[c], "-version")) {
+      const int dec_version = WebPGetDecoderVersion();
+      const int dmux_version = WebPGetDemuxVersion();
+      printf("WebP Decoder version: %d.%d.%d\nWebP Demux version: %d.%d.%d\n",
+             (dec_version >> 16) & 0xff, (dec_version >> 8) & 0xff,
+             dec_version & 0xff, (dmux_version >> 16) & 0xff,
+             (dmux_version >> 8) & 0xff, dmux_version & 0xff);
+      FREE_WARGV_AND_RETURN(0);
+    } else if (!strcmp(argv[c], "-mt")) {
+      config->options.use_threads = 1;
+    } else if (!strcmp(argv[c], "--")) {
+      if (c < argc - 1) kParams.file_name = (const char*)GET_WARGV(argv, ++c);
+      break;
+    } else if (argv[c][0] == '-') {
+      printf("Unknown option '%s'\n", argv[c]);
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    } else {
+      kParams.file_name = (const char*)GET_WARGV(argv, c);
+    }
+
+    if (parse_error) {
+      Help();
+      FREE_WARGV_AND_RETURN(-1);
+    }
+  }
+
+  if (kParams.file_name == NULL) {
+    printf("missing input file!!\n");
+    Help();
+    FREE_WARGV_AND_RETURN(0);
+  }
+
+  if (!ImgIoUtilReadFile(kParams.file_name,
+                         &kParams.data.bytes, &kParams.data.size)) {
+    goto Error;
+  }
+
+  if (!WebPGetInfo(kParams.data.bytes, kParams.data.size, NULL, NULL)) {
+    fprintf(stderr, "Input file doesn't appear to be WebP format.\n");
+    goto Error;
+  }
+
+  kParams.dmux = WebPDemux(&kParams.data);
+  if (kParams.dmux == NULL) {
+    fprintf(stderr, "Could not create demuxing object!\n");
+    goto Error;
+  }
+
+  kParams.canvas_width = WebPDemuxGetI(kParams.dmux, WEBP_FF_CANVAS_WIDTH);
+  kParams.canvas_height = WebPDemuxGetI(kParams.dmux, WEBP_FF_CANVAS_HEIGHT);
+  if (kParams.print_info) {
+    printf("Canvas: %d x %d\n", kParams.canvas_width, kParams.canvas_height);
+  }
+
+  ClearPreviousFrame();
+
+  memset(&kParams.iccp, 0, sizeof(kParams.iccp));
+  kParams.has_color_profile =
+      !!(WebPDemuxGetI(kParams.dmux, WEBP_FF_FORMAT_FLAGS) & ICCP_FLAG);
+  if (kParams.has_color_profile) {
+#ifdef WEBP_HAVE_QCMS
+    if (!WebPDemuxGetChunk(kParams.dmux, "ICCP", 1, &kParams.iccp)) goto Error;
+    printf("VP8X: Found color profile\n");
+#else
+    fprintf(stderr, "Warning: color profile present, but qcms is unavailable!\n"
+            "Build libqcms from Mozilla or Chromium and define WEBP_HAVE_QCMS "
+            "before building.\n");
+#endif
+  }
+
+  if (!WebPDemuxGetFrame(kParams.dmux, 1, curr)) goto Error;
+
+  kParams.has_animation = (curr->num_frames > 1);
+  kParams.loop_count = (int)WebPDemuxGetI(kParams.dmux, WEBP_FF_LOOP_COUNT);
+  kParams.bg_color = WebPDemuxGetI(kParams.dmux, WEBP_FF_BACKGROUND_COLOR);
+  printf("VP8X: Found %d images in file (loop count = %d)\n",
+         curr->num_frames, kParams.loop_count);
+
+  // Decode first frame
+  if (!Decode()) goto Error;
+
+  // Position iterator to last frame. Next call to HandleDisplay will wrap over.
+  // We take this into account by bumping up loop_count.
+  WebPDemuxGetFrame(kParams.dmux, 0, curr);
+  if (kParams.loop_count) ++kParams.loop_count;
+
+#if defined(__unix__) || defined(__CYGWIN__)
+  // Work around GLUT compositor bug.
+  // https://bugs.launchpad.net/ubuntu/+source/freeglut/+bug/369891
+  setenv("XLIB_SKIP_ARGB_VISUALS", "1", 1);
+#endif
+
+  // Start display (and timer)
+  glutInit(&argc, argv);
+#ifdef FREEGLUT
+  glutSetOption(GLUT_ACTION_ON_WINDOW_CLOSE, GLUT_ACTION_CONTINUE_EXECUTION);
+#endif
+  StartDisplay();
+
+  if (kParams.has_animation) glutTimerFunc(0, decode_callback, 0);
+  glutMainLoop();
+
+  // Should only be reached when using FREEGLUT:
+  ClearParams();
+  FREE_WARGV_AND_RETURN(0);
+
+ Error:
+  ClearParams();
+  FREE_WARGV_AND_RETURN(-1);
+}
+
+#else   // !WEBP_HAVE_GL
+
+int main(int argc, const char* argv[]) {
+  fprintf(stderr, "OpenGL support not enabled in %s.\n", argv[0]);
+  (void)argc;
+  return 0;
+}
+
+#endif
+
+//------------------------------------------------------------------------------
--- a/external/libwebp/libwebp/examples/webpinfo.c
+++ b/external/libwebp/libwebp/examples/webpinfo.c
--- a/external/libwebp/libwebp/examples/webpmux.c
+++ b/external/libwebp/libwebp/examples/webpmux.c
--- a/external/libwebp/libwebp/extras/Makefile.am
+++ b/external/libwebp/libwebp/extras/Makefile.am
@@ -0,0 +1,44 @@
+AM_CPPFLAGS += -I$(top_builddir) -I$(top_srcdir)
+AM_CPPFLAGS += -I$(top_builddir)/src -I$(top_srcdir)/src
+noinst_LTLIBRARIES = libwebpextras.la
+
+noinst_HEADERS =
+noinst_HEADERS += ../src/webp/types.h
+
+libwebpextras_la_SOURCES =
+libwebpextras_la_SOURCES += extras.c extras.h quality_estimate.c
+
+libwebpextras_la_CPPFLAGS = $(AM_CPPFLAGS)
+libwebpextras_la_LDFLAGS = -lm
+libwebpextras_la_LIBADD = ../src/libwebp.la
+
+noinst_PROGRAMS =
+noinst_PROGRAMS += webp_quality
+if BUILD_DEMUX
+  noinst_PROGRAMS += get_disto
+endif
+if BUILD_VWEBP_SDL
+  noinst_PROGRAMS += vwebp_sdl
+endif
+
+get_disto_SOURCES  = get_disto.c
+get_disto_CPPFLAGS = $(AM_CPPFLAGS)
+get_disto_LDADD =
+get_disto_LDADD += ../imageio/libimageio_util.la
+get_disto_LDADD += ../imageio/libimagedec.la
+get_disto_LDADD += ../src/libwebp.la
+get_disto_LDADD += $(PNG_LIBS) $(JPEG_LIBS) $(TIFF_LIBS)
+
+webp_quality_SOURCES  = webp_quality.c
+webp_quality_CPPFLAGS = $(AM_CPPFLAGS)
+webp_quality_LDADD =
+webp_quality_LDADD += ../imageio/libimageio_util.la
+webp_quality_LDADD += libwebpextras.la
+webp_quality_LDADD += ../src/libwebp.la
+
+vwebp_sdl_SOURCES  = vwebp_sdl.c webp_to_sdl.c webp_to_sdl.h
+vwebp_sdl_CPPFLAGS = $(AM_CPPFLAGS) $(SDL_INCLUDES)
+vwebp_sdl_LDADD =
+vwebp_sdl_LDADD += ../imageio/libimageio_util.la
+vwebp_sdl_LDADD += ../src/libwebp.la
+vwebp_sdl_LDADD += $(SDL_LIBS)
--- a/external/libwebp/libwebp/extras/extras.c
+++ b/external/libwebp/libwebp/extras/extras.c
@@ -0,0 +1,162 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Additional WebP utilities.
+//
+
+#include "extras/extras.h"
+#include "webp/format_constants.h"
+#include "src/dsp/dsp.h"
+
+#include <assert.h>
+#include <string.h>
+
+#define XTRA_MAJ_VERSION 1
+#define XTRA_MIN_VERSION 3
+#define XTRA_REV_VERSION 1
+
+//------------------------------------------------------------------------------
+
+int WebPGetExtrasVersion(void) {
+  return (XTRA_MAJ_VERSION << 16) | (XTRA_MIN_VERSION << 8) | XTRA_REV_VERSION;
+}
+
+//------------------------------------------------------------------------------
+
+int WebPImportGray(const uint8_t* gray_data, WebPPicture* pic) {
+  int y, width, uv_width;
+  if (pic == NULL || gray_data == NULL) return 0;
+  pic->colorspace = WEBP_YUV420;
+  if (!WebPPictureAlloc(pic)) return 0;
+  width = pic->width;
+  uv_width = (width + 1) >> 1;
+  for (y = 0; y < pic->height; ++y) {
+    memcpy(pic->y + y * pic->y_stride, gray_data, width);
+    gray_data += width;    // <- we could use some 'data_stride' here if needed
+    if ((y & 1) == 0) {
+      memset(pic->u + (y >> 1) * pic->uv_stride, 128, uv_width);
+      memset(pic->v + (y >> 1) * pic->uv_stride, 128, uv_width);
+    }
+  }
+  return 1;
+}
+
+int WebPImportRGB565(const uint8_t* rgb565, WebPPicture* pic) {
+  int x, y;
+  uint32_t* dst;
+  if (pic == NULL || rgb565 == NULL) return 0;
+  pic->colorspace = WEBP_YUV420;
+  pic->use_argb = 1;
+  if (!WebPPictureAlloc(pic)) return 0;
+  dst = pic->argb;
+  for (y = 0; y < pic->height; ++y) {
+    const int width = pic->width;
+    for (x = 0; x < width; ++x) {
+#if defined(WEBP_SWAP_16BIT_CSP) && (WEBP_SWAP_16BIT_CSP == 1)
+      const uint32_t rg = rgb565[2 * x + 1];
+      const uint32_t gb = rgb565[2 * x + 0];
+#else
+      const uint32_t rg = rgb565[2 * x + 0];
+      const uint32_t gb = rgb565[2 * x + 1];
+#endif
+      uint32_t r = rg & 0xf8;
+      uint32_t g = ((rg << 5) | (gb >> 3)) & 0xfc;
+      uint32_t b = (gb << 5);
+      // dithering
+      r = r | (r >> 5);
+      g = g | (g >> 6);
+      b = b | (b >> 5);
+      dst[x] = (0xffu << 24) | (r << 16) | (g << 8) | b;
+    }
+    rgb565 += 2 * width;
+    dst += pic->argb_stride;
+  }
+  return 1;
+}
+
+int WebPImportRGB4444(const uint8_t* rgb4444, WebPPicture* pic) {
+  int x, y;
+  uint32_t* dst;
+  if (pic == NULL || rgb4444 == NULL) return 0;
+  pic->colorspace = WEBP_YUV420;
+  pic->use_argb = 1;
+  if (!WebPPictureAlloc(pic)) return 0;
+  dst = pic->argb;
+  for (y = 0; y < pic->height; ++y) {
+    const int width = pic->width;
+    for (x = 0; x < width; ++x) {
+#if defined(WEBP_SWAP_16BIT_CSP) && (WEBP_SWAP_16BIT_CSP == 1)
+      const uint32_t rg = rgb4444[2 * x + 1];
+      const uint32_t ba = rgb4444[2 * x + 0];
+#else
+      const uint32_t rg = rgb4444[2 * x + 0];
+      const uint32_t ba = rgb4444[2 * x + 1];
+#endif
+      uint32_t r = rg & 0xf0;
+      uint32_t g = (rg << 4);
+      uint32_t b = (ba & 0xf0);
+      uint32_t a = (ba << 4);
+      // dithering
+      r = r | (r >> 4);
+      g = g | (g >> 4);
+      b = b | (b >> 4);
+      a = a | (a >> 4);
+      dst[x] = (a << 24) | (r << 16) | (g << 8) | b;
+    }
+    rgb4444 += 2 * width;
+    dst += pic->argb_stride;
+  }
+  return 1;
+}
+
+int WebPImportColorMappedARGB(const uint8_t* indexed, int indexed_stride,
+                              const uint32_t palette[], int palette_size,
+                              WebPPicture* pic) {
+  int x, y;
+  uint32_t* dst;
+  // 256 as the input buffer is uint8_t.
+  assert(MAX_PALETTE_SIZE <= 256);
+  if (pic == NULL || indexed == NULL || indexed_stride < pic->width ||
+      palette == NULL || palette_size > MAX_PALETTE_SIZE || palette_size <= 0) {
+    return 0;
+  }
+  pic->use_argb = 1;
+  if (!WebPPictureAlloc(pic)) return 0;
+  dst = pic->argb;
+  for (y = 0; y < pic->height; ++y) {
+    for (x = 0; x < pic->width; ++x) {
+      // Make sure we are within the palette.
+      if (indexed[x] >= palette_size) {
+        WebPPictureFree(pic);
+        return 0;
+      }
+      dst[x] = palette[indexed[x]];
+    }
+    indexed += indexed_stride;
+    dst += pic->argb_stride;
+  }
+  return 1;
+}
+
+//------------------------------------------------------------------------------
+
+int WebPUnmultiplyARGB(WebPPicture* pic) {
+  int y;
+  uint32_t* dst;
+  if (pic == NULL || pic->use_argb != 1 || pic->argb == NULL) return 0;
+  WebPInitAlphaProcessing();
+  dst = pic->argb;
+  for (y = 0; y < pic->height; ++y) {
+    WebPMultARGBRow(dst, pic->width, /*inverse=*/1);
+    dst += pic->argb_stride;
+  }
+  return 1;
+}
+
+//------------------------------------------------------------------------------
--- a/external/libwebp/libwebp/extras/extras.h
+++ b/external/libwebp/libwebp/extras/extras.h
@@ -0,0 +1,77 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+
+#ifndef WEBP_EXTRAS_EXTRAS_H_
+#define WEBP_EXTRAS_EXTRAS_H_
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "webp/encode.h"
+
+#define WEBP_EXTRAS_ABI_VERSION 0x0002    // MAJOR(8b) + MINOR(8b)
+
+//------------------------------------------------------------------------------
+
+// Returns the version number of the extras library, packed in hexadecimal using
+// 8bits for each of major/minor/revision. E.g: v2.5.7 is 0x020507.
+WEBP_EXTERN int WebPGetExtrasVersion(void);
+
+//------------------------------------------------------------------------------
+// Ad-hoc colorspace importers.
+
+// Import luma sample (gray scale image) into 'picture'. The 'picture'
+// width and height must be set prior to calling this function.
+WEBP_EXTERN int WebPImportGray(const uint8_t* gray, WebPPicture* picture);
+
+// Import rgb sample in RGB565 packed format into 'picture'. The 'picture'
+// width and height must be set prior to calling this function.
+WEBP_EXTERN int WebPImportRGB565(const uint8_t* rgb565, WebPPicture* pic);
+
+// Import rgb sample in RGB4444 packed format into 'picture'. The 'picture'
+// width and height must be set prior to calling this function.
+WEBP_EXTERN int WebPImportRGB4444(const uint8_t* rgb4444, WebPPicture* pic);
+
+// Import a color mapped image. The number of colors is less or equal to
+// MAX_PALETTE_SIZE. 'pic' must have been initialized. Its content, if any,
+// will be discarded. Returns 'false' in case of error, or if indexed[] contains
+// invalid indices.
+WEBP_EXTERN int
+WebPImportColorMappedARGB(const uint8_t* indexed, int indexed_stride,
+                          const uint32_t palette[], int palette_size,
+                          WebPPicture* pic);
+
+// Convert the ARGB content of 'pic' from associated to unassociated.
+// 'pic' can be for instance the result of calling of some WebPPictureImportXXX
+// functions, with pic->use_argb set to 'true'. It is assumed (and not checked)
+// that the pre-multiplied r/g/b values as less or equal than the alpha value.
+// Return false in case of error (invalid parameter, ...).
+WEBP_EXTERN int WebPUnmultiplyARGB(WebPPicture* pic);
+
+//------------------------------------------------------------------------------
+
+// Parse a bitstream, search for VP8 (lossy) header and report a
+// rough estimation of the quality factor used for compressing the bitstream.
+// If the bitstream is in lossless format, the special value '101' is returned.
+// Otherwise (lossy bitstream), the returned value is in the range [0..100].
+// Any error (invalid bitstream, animated WebP, incomplete header, etc.)
+// will return a value of -1.
+WEBP_EXTERN int VP8EstimateQuality(const uint8_t* const data, size_t size);
+
+//------------------------------------------------------------------------------
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_EXTRAS_EXTRAS_H_
--- a/external/libwebp/libwebp/extras/get_disto.c
+++ b/external/libwebp/libwebp/extras/get_disto.c
@@ -0,0 +1,356 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Simple tool to load two webp/png/jpg/tiff files and compute PSNR/SSIM.
+// This is mostly a wrapper around WebPPictureDistortion().
+//
+/*
+ gcc -o get_disto get_disto.c -O3 -I../ -L../examples -L../imageio \
+    -lexample_util -limageio_util -limagedec -lwebp -L/opt/local/lib \
+    -lpng -lz -ljpeg -ltiff -lm -lpthread
+*/
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/encode.h"
+#include "imageio/image_dec.h"
+#include "imageio/imageio_util.h"
+#include "../examples/unicode.h"
+
+static size_t ReadPicture(const char* const filename, WebPPicture* const pic,
+                          int keep_alpha) {
+  const uint8_t* data = NULL;
+  size_t data_size = 0;
+  WebPImageReader reader = NULL;
+  int ok = ImgIoUtilReadFile(filename, &data, &data_size);
+  if (!ok) goto End;
+
+  pic->use_argb = 1;  // force ARGB
+
+#ifdef HAVE_WINCODEC_H
+  // Try to decode the file using WIC falling back to the other readers for
+  // e.g., WebP.
+  ok = ReadPictureWithWIC(filename, pic, keep_alpha, NULL);
+  if (ok) goto End;
+#endif
+  reader = WebPGuessImageReader(data, data_size);
+  ok = reader(data, data_size, pic, keep_alpha, NULL);
+
+ End:
+  if (!ok) {
+    WFPRINTF(stderr, "Error! Could not process file %s\n",
+             (const W_CHAR*)filename);
+  }
+  free((void*)data);
+  return ok ? data_size : 0;
+}
+
+static void RescalePlane(uint8_t* plane, int width, int height,
+                         int x_stride, int y_stride, int max) {
+  const uint32_t factor = (max > 0) ? (255u << 16) / max : 0;
+  int x, y;
+  for (y = 0; y < height; ++y) {
+    uint8_t* const ptr = plane + y * y_stride;
+    for (x = 0; x < width * x_stride; x += x_stride) {
+      const uint32_t diff = (ptr[x] * factor + (1 << 15)) >> 16;
+      ptr[x] = diff;
+    }
+  }
+}
+
+// Return the max absolute difference.
+static int DiffScaleChannel(uint8_t* src1, int stride1,
+                            const uint8_t* src2, int stride2,
+                            int x_stride, int w, int h, int do_scaling) {
+  int x, y;
+  int max = 0;
+  for (y = 0; y < h; ++y) {
+    uint8_t* const ptr1 = src1 + y * stride1;
+    const uint8_t* const ptr2 = src2 + y * stride2;
+    for (x = 0; x < w * x_stride; x += x_stride) {
+      const int diff = abs(ptr1[x] - ptr2[x]);
+      if (diff > max) max = diff;
+      ptr1[x] = diff;
+    }
+  }
+
+  if (do_scaling) RescalePlane(src1, w, h, x_stride, stride1, max);
+  return max;
+}
+
+//------------------------------------------------------------------------------
+// SSIM calculation. We re-implement these functions here, out of dsp/, to avoid
+// breaking the library's hidden visibility. This code duplication avoids the
+// bigger annoyance of having to open up internal details of libdsp...
+
+#define SSIM_KERNEL 3   // total size of the kernel: 2 * SSIM_KERNEL + 1
+
+// struct for accumulating statistical moments
+typedef struct {
+  uint32_t w;              // sum(w_i) : sum of weights
+  uint32_t xm, ym;         // sum(w_i * x_i), sum(w_i * y_i)
+  uint32_t xxm, xym, yym;  // sum(w_i * x_i * x_i), etc.
+} DistoStats;
+
+// hat-shaped filter. Sum of coefficients is equal to 16.
+static const uint32_t kWeight[2 * SSIM_KERNEL + 1] = { 1, 2, 3, 4, 3, 2, 1 };
+
+static WEBP_INLINE double SSIMCalculation(const DistoStats* const stats) {
+  const uint32_t N = stats->w;
+  const uint32_t w2 =  N * N;
+  const uint32_t C1 = 20 * w2;
+  const uint32_t C2 = 60 * w2;
+  const uint32_t C3 = 8 * 8 * w2;   // 'dark' limit ~= 6
+  const uint64_t xmxm = (uint64_t)stats->xm * stats->xm;
+  const uint64_t ymym = (uint64_t)stats->ym * stats->ym;
+  if (xmxm + ymym >= C3) {
+    const int64_t xmym = (int64_t)stats->xm * stats->ym;
+    const int64_t sxy = (int64_t)stats->xym * N - xmym;    // can be negative
+    const uint64_t sxx = (uint64_t)stats->xxm * N - xmxm;
+    const uint64_t syy = (uint64_t)stats->yym * N - ymym;
+    // we descale by 8 to prevent overflow during the fnum/fden multiply.
+    const uint64_t num_S = (2 * (uint64_t)(sxy < 0 ? 0 : sxy) + C2) >> 8;
+    const uint64_t den_S = (sxx + syy + C2) >> 8;
+    const uint64_t fnum = (2 * xmym + C1) * num_S;
+    const uint64_t fden = (xmxm + ymym + C1) * den_S;
+    const double r = (double)fnum / fden;
+    assert(r >= 0. && r <= 1.0);
+    return r;
+  }
+  return 1.;   // area is too dark to contribute meaningfully
+}
+
+static double SSIMGetClipped(const uint8_t* src1, int stride1,
+                             const uint8_t* src2, int stride2,
+                             int xo, int yo, int W, int H) {
+  DistoStats stats = { 0, 0, 0, 0, 0, 0 };
+  const int ymin = (yo - SSIM_KERNEL < 0) ? 0 : yo - SSIM_KERNEL;
+  const int ymax = (yo + SSIM_KERNEL > H - 1) ? H - 1 : yo + SSIM_KERNEL;
+  const int xmin = (xo - SSIM_KERNEL < 0) ? 0 : xo - SSIM_KERNEL;
+  const int xmax = (xo + SSIM_KERNEL > W - 1) ? W - 1 : xo + SSIM_KERNEL;
+  int x, y;
+  src1 += ymin * stride1;
+  src2 += ymin * stride2;
+  for (y = ymin; y <= ymax; ++y, src1 += stride1, src2 += stride2) {
+    for (x = xmin; x <= xmax; ++x) {
+      const uint32_t w = kWeight[SSIM_KERNEL + x - xo]
+                       * kWeight[SSIM_KERNEL + y - yo];
+      const uint32_t s1 = src1[x];
+      const uint32_t s2 = src2[x];
+      stats.w   += w;
+      stats.xm  += w * s1;
+      stats.ym  += w * s2;
+      stats.xxm += w * s1 * s1;
+      stats.xym += w * s1 * s2;
+      stats.yym += w * s2 * s2;
+    }
+  }
+  return SSIMCalculation(&stats);
+}
+
+// Compute SSIM-score map. Return -1 in case of error, max diff otherwise.
+static int SSIMScaleChannel(uint8_t* src1, int stride1,
+                            const uint8_t* src2, int stride2,
+                            int x_stride, int w, int h, int do_scaling) {
+  int x, y;
+  int max = 0;
+  uint8_t* const plane1 = (uint8_t*)malloc(2 * w * h * sizeof(*plane1));
+  uint8_t* const plane2 = plane1 + w * h;
+  if (plane1 == NULL) return -1;
+
+  // extract plane
+  for (y = 0; y < h; ++y) {
+    for (x = 0; x < w; ++x) {
+      plane1[x + y * w] = src1[x * x_stride + y * stride1];
+      plane2[x + y * w] = src2[x * x_stride + y * stride2];
+    }
+  }
+  for (y = 0; y < h; ++y) {
+    for (x = 0; x < w; ++x) {
+      const double ssim = SSIMGetClipped(plane1, w, plane2, w, x, y, w, h);
+      int diff = (int)(255 * (1. - ssim));
+      if (diff < 0) {
+        diff = 0;
+      } else if (diff > max) {
+        max = diff;
+      }
+      src1[x * x_stride + y * stride1] = (diff > 255) ? 255u : (uint8_t)diff;
+    }
+  }
+  free(plane1);
+
+  if (do_scaling) RescalePlane(src1, w, h, x_stride, stride1, max);
+  return max;
+}
+
+// Convert an argb picture to luminance.
+static void ConvertToGray(WebPPicture* const pic) {
+  int x, y;
+  assert(pic != NULL);
+  assert(pic->use_argb);
+  for (y = 0; y < pic->height; ++y) {
+    uint32_t* const row = &pic->argb[y * pic->argb_stride];
+    for (x = 0; x < pic->width; ++x) {
+      const uint32_t argb = row[x];
+      const uint32_t r = (argb >> 16) & 0xff;
+      const uint32_t g = (argb >>  8) & 0xff;
+      const uint32_t b = (argb >>  0) & 0xff;
+      // We use BT.709 for converting to luminance.
+      const uint32_t Y = (uint32_t)(0.2126 * r + 0.7152 * g + 0.0722 * b + .5);
+      row[x] = (argb & 0xff000000u) | (Y * 0x010101u);
+    }
+  }
+}
+
+static void Help(void) {
+  fprintf(stderr,
+          "Usage: get_disto [-ssim][-psnr][-alpha] compressed.webp orig.webp\n"
+          "  -ssim ..... print SSIM distortion\n"
+          "  -psnr ..... print PSNR distortion (default)\n"
+          "  -alpha .... preserve alpha plane\n"
+          "  -h ........ this message\n"
+          "  -o <file> . save the diff map as a WebP lossless file\n"
+          "  -scale .... scale the difference map to fit [0..255] range\n"
+          "  -gray ..... use grayscale for difference map (-scale)\n"
+          "\nSupported input formats:\n  %s\n",
+          WebPGetEnabledInputFileFormats());
+}
+
+int main(int argc, const char* argv[]) {
+  WebPPicture pic1, pic2;
+  size_t size1 = 0, size2 = 0;
+  int ret = 1;
+  float disto[5];
+  int type = 0;
+  int c;
+  int help = 0;
+  int keep_alpha = 0;
+  int scale = 0;
+  int use_gray = 0;
+  const char* name1 = NULL;
+  const char* name2 = NULL;
+  const char* output = NULL;
+
+  INIT_WARGV(argc, argv);
+
+  if (!WebPPictureInit(&pic1) || !WebPPictureInit(&pic2)) {
+    fprintf(stderr, "Can't init pictures\n");
+    FREE_WARGV_AND_RETURN(1);
+  }
+
+  for (c = 1; c < argc; ++c) {
+    if (!strcmp(argv[c], "-ssim")) {
+      type = 1;
+    } else if (!strcmp(argv[c], "-psnr")) {
+      type = 0;
+    } else if (!strcmp(argv[c], "-alpha")) {
+      keep_alpha = 1;
+    } else if (!strcmp(argv[c], "-scale")) {
+      scale = 1;
+    } else if (!strcmp(argv[c], "-gray")) {
+      use_gray = 1;
+    } else if (!strcmp(argv[c], "-h")) {
+      help = 1;
+      ret = 0;
+    } else if (!strcmp(argv[c], "-o")) {
+      if (++c == argc) {
+        fprintf(stderr, "missing file name after %s option.\n", argv[c - 1]);
+        goto End;
+      }
+      output = (const char*)GET_WARGV(argv, c);
+    } else if (name1 == NULL) {
+      name1 = (const char*)GET_WARGV(argv, c);
+    } else {
+      name2 = (const char*)GET_WARGV(argv, c);
+    }
+  }
+  if (help || name1 == NULL || name2 == NULL) {
+    if (!help) {
+      fprintf(stderr, "Error: missing arguments.\n");
+    }
+    Help();
+    goto End;
+  }
+  size1 = ReadPicture(name1, &pic1, 1);
+  size2 = ReadPicture(name2, &pic2, 1);
+  if (size1 == 0 || size2 == 0) goto End;
+
+  if (!keep_alpha) {
+    WebPBlendAlpha(&pic1, 0x00000000);
+    WebPBlendAlpha(&pic2, 0x00000000);
+  }
+
+  if (!WebPPictureDistortion(&pic1, &pic2, type, disto)) {
+    fprintf(stderr, "Error while computing the distortion.\n");
+    goto End;
+  }
+  printf("%u %.2f    %.2f %.2f %.2f %.2f [ %.2f bpp ]\n",
+         (unsigned int)size1,
+         disto[4], disto[0], disto[1], disto[2], disto[3],
+         8.f * size1 / pic1.width / pic1.height);
+
+  if (output != NULL) {
+    uint8_t* data = NULL;
+    size_t data_size = 0;
+    if (pic1.use_argb != pic2.use_argb) {
+      fprintf(stderr, "Pictures are not in the same argb format. "
+                      "Can't save the difference map.\n");
+      goto End;
+    }
+    if (pic1.use_argb) {
+      int n;
+      fprintf(stderr, "max differences per channel: ");
+      for (n = 0; n < 3; ++n) {    // skip the alpha channel
+        const int range = (type == 1) ?
+          SSIMScaleChannel((uint8_t*)pic1.argb + n, pic1.argb_stride * 4,
+                           (const uint8_t*)pic2.argb + n, pic2.argb_stride * 4,
+                           4, pic1.width, pic1.height, scale) :
+          DiffScaleChannel((uint8_t*)pic1.argb + n, pic1.argb_stride * 4,
+                           (const uint8_t*)pic2.argb + n, pic2.argb_stride * 4,
+                           4, pic1.width, pic1.height, scale);
+        if (range < 0) fprintf(stderr, "\nError computing diff map\n");
+        fprintf(stderr, "[%d]", range);
+      }
+      fprintf(stderr, "\n");
+      if (use_gray) ConvertToGray(&pic1);
+    } else {
+      fprintf(stderr, "Can only compute the difference map in ARGB format.\n");
+      goto End;
+    }
+#if !defined(WEBP_REDUCE_CSP)
+    data_size = WebPEncodeLosslessBGRA((const uint8_t*)pic1.argb,
+                                       pic1.width, pic1.height,
+                                       pic1.argb_stride * 4,
+                                       &data);
+    if (data_size == 0) {
+      fprintf(stderr, "Error during lossless encoding.\n");
+      goto End;
+    }
+    ret = ImgIoUtilWriteFile(output, data, data_size) ? 0 : 1;
+    WebPFree(data);
+    if (ret) goto End;
+#else
+    (void)data;
+    (void)data_size;
+    fprintf(stderr, "Cannot save the difference map. Please recompile "
+                    "without the WEBP_REDUCE_CSP flag.\n");
+#endif  // WEBP_REDUCE_CSP
+  }
+  ret = 0;
+
+ End:
+  WebPPictureFree(&pic1);
+  WebPPictureFree(&pic2);
+  FREE_WARGV_AND_RETURN(ret);
+}
--- a/external/libwebp/libwebp/extras/quality_estimate.c
+++ b/external/libwebp/libwebp/extras/quality_estimate.c
@@ -0,0 +1,129 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  VP8EstimateQuality(): rough encoding quality estimate
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include "extras/extras.h"
+#include "webp/decode.h"
+
+#include <math.h>
+
+//------------------------------------------------------------------------------
+
+#define INVALID_BIT_POS (1ull << 63)
+
+// In most cases, we don't need to use a full arithmetic decoder, since
+// all the header's bits are written using a uniform probability of 128.
+// We can just parse the header as if it was bits (works in 99.999% cases).
+static WEBP_INLINE uint32_t GetBit(const uint8_t* const data, size_t nb,
+                                   uint64_t max_size, uint64_t* const bit_pos) {
+  uint32_t val = 0;
+  if (*bit_pos + nb <= 8 * max_size) {
+    while (nb-- > 0) {
+      const uint64_t p = (*bit_pos)++;
+      const int bit = !!(data[p >> 3] & (128 >> ((p & 7))));
+      val = (val << 1) | bit;
+    }
+  } else {
+    *bit_pos = INVALID_BIT_POS;
+  }
+  return val;
+}
+
+#define GET_BIT(n) GetBit(data, (n), size, &bit_pos)
+#define CONDITIONAL_SKIP(n) (GET_BIT(1) ? GET_BIT((n)) : 0)
+
+int VP8EstimateQuality(const uint8_t* const data, size_t size) {
+  size_t pos = 0;
+  uint64_t bit_pos;
+  uint64_t sig = 0x00;
+  int ok = 0;
+  int Q = -1;
+  WebPBitstreamFeatures features;
+
+  if (data == NULL) return -1;
+
+  if (WebPGetFeatures(data, size, &features) != VP8_STATUS_OK) {
+    return -1;   // invalid file
+  }
+  if (features.format == 2) return 101;  // lossless
+  if (features.format == 0 || features.has_animation) return -1;   // mixed
+
+  while (pos < size) {
+    sig = (sig >> 8) | ((uint64_t)data[pos++] << 40);
+    if ((sig >> 24) == 0x2a019dull) {
+      ok = 1;
+      break;
+    }
+  }
+  if (!ok) return -1;
+  if (pos + 4 > size) return -1;
+
+  // Skip main Header
+  // width  = (data[pos + 0] | (data[pos + 1] << 8)) & 0x3fff;
+  // height = (data[pos + 2] | (data[pos + 3] << 8)) & 0x3fff;
+  pos += 4;
+  bit_pos = pos * 8;
+
+  GET_BIT(2);  // colorspace + clamp type
+
+  // Segment header
+  if (GET_BIT(1)) {       // use_segment_
+    int s;
+    const int update_map = GET_BIT(1);
+    if (GET_BIT(1)) {     // update data
+      const int absolute_delta = GET_BIT(1);
+      int q[4]  = { 0, 0, 0, 0 };
+      for (s = 0; s < 4; ++s) {
+        if (GET_BIT(1)) {
+          q[s] = GET_BIT(7);
+          if (GET_BIT(1)) q[s] = -q[s];   // sign
+        }
+      }
+      if (absolute_delta) Q = q[0];  // just use the first segment's quantizer
+      for (s = 0; s < 4; ++s) CONDITIONAL_SKIP(7);   //  filter strength
+    }
+    if (update_map) {
+      for (s = 0; s < 3; ++s) CONDITIONAL_SKIP(8);
+    }
+  }
+  // Filter header
+  GET_BIT(1 + 6 + 3);     // simple + level + sharpness
+  if (GET_BIT(1)) {       // use_lf_delta
+    if (GET_BIT(1)) {     // update lf_delta?
+      int n;
+      for (n = 0; n < 4 + 4; ++n) CONDITIONAL_SKIP(6);
+    }
+  }
+  // num partitions
+  GET_BIT(2);
+
+  // ParseQuant
+  {
+    const int base_q = GET_BIT(7);
+    /* dqy1_dc = */ CONDITIONAL_SKIP(5);
+    /* dqy2_dc = */ CONDITIONAL_SKIP(5);
+    /* dqy2_ac = */ CONDITIONAL_SKIP(5);
+    /* dquv_dc = */ CONDITIONAL_SKIP(5);
+    /* dquv_ac = */ CONDITIONAL_SKIP(5);
+
+    if (Q < 0) Q = base_q;
+  }
+  if (bit_pos == INVALID_BIT_POS) return -1;
+
+  // base mapping
+  Q = (127 - Q) * 100 / 127;
+  // correction for power-law behavior in low range
+  if (Q < 80) {
+    Q = (int)(pow(Q / 80., 1. / 0.38) * 80);
+  }
+  return Q;
+}
--- a/external/libwebp/libwebp/extras/vwebp_sdl.c
+++ b/external/libwebp/libwebp/extras/vwebp_sdl.c
@@ -0,0 +1,101 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Simple SDL-based WebP file viewer.
+// Does not support animation, just static images.
+//
+// Press 'q' to exit.
+//
+// Author: James Zern (jzern@google.com)
+
+#include <stdio.h>
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#if defined(WEBP_HAVE_SDL)
+
+#include "webp_to_sdl.h"
+#include "webp/decode.h"
+#include "imageio/imageio_util.h"
+#include "../examples/unicode.h"
+
+#if defined(WEBP_HAVE_JUST_SDL_H)
+#include <SDL.h>
+#else
+#include <SDL/SDL.h>
+#endif
+
+static void ProcessEvents(void) {
+  int done = 0;
+  SDL_Event event;
+  while (!done && SDL_WaitEvent(&event)) {
+    switch (event.type) {
+      case SDL_KEYUP:
+        switch (event.key.keysym.sym) {
+          case SDLK_q: done = 1; break;
+          default: break;
+        }
+        break;
+      default: break;
+    }
+  }
+}
+
+int main(int argc, char* argv[]) {
+  int c;
+  int ok = 0;
+
+  INIT_WARGV(argc, argv);
+
+  for (c = 1; c < argc; ++c) {
+    const char* file = NULL;
+    const uint8_t* webp = NULL;
+    size_t webp_size = 0;
+    if (!strcmp(argv[c], "-h")) {
+      printf("Usage: %s [-h] image.webp [more_files.webp...]\n", argv[0]);
+      FREE_WARGV_AND_RETURN(0);
+    } else {
+      file = (const char*)GET_WARGV(argv, c);
+    }
+    if (file == NULL) continue;
+    if (!ImgIoUtilReadFile(file, &webp, &webp_size)) {
+      WFPRINTF(stderr, "Error opening file: %s\n", (const W_CHAR*)file);
+      goto Error;
+    }
+    if (webp_size != (size_t)(int)webp_size) {
+      free((void*)webp);
+      fprintf(stderr, "File too large.\n");
+      goto Error;
+    }
+    ok = WebPToSDL((const char*)webp, (int)webp_size);
+    free((void*)webp);
+    if (!ok) {
+      WFPRINTF(stderr, "Error decoding file %s\n", (const W_CHAR*)file);
+      goto Error;
+    }
+    ProcessEvents();
+  }
+  ok = 1;
+
+ Error:
+  SDL_Quit();
+  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+}
+
+#else  // !WEBP_HAVE_SDL
+
+int main(int argc, const char* argv[]) {
+  fprintf(stderr, "SDL support not enabled in %s.\n", argv[0]);
+  (void)argc;
+  return 0;
+}
+
+#endif
--- a/external/libwebp/libwebp/extras/webp_quality.c
+++ b/external/libwebp/libwebp/extras/webp_quality.c
@@ -0,0 +1,54 @@
+// Simple tool to roughly evaluate the quality encoding of a webp bitstream
+//
+// Result is a *rough* estimation of the quality. You should just consider
+// the bucket it's in (q > 80? > 50? > 20?) and not take it for face value.
+/*
+ gcc -o webp_quality webp_quality.c -O3 -I../ -L. -L../imageio \
+    -limageio_util -lwebpextras -lwebp -lm -lpthread
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "extras/extras.h"
+#include "imageio/imageio_util.h"
+#include "../examples/unicode.h"
+
+int main(int argc, const char* argv[]) {
+  int c;
+  int quiet = 0;
+  int ok = 1;
+
+  INIT_WARGV(argc, argv);
+
+  for (c = 1; ok && c < argc; ++c) {
+    if (!strcmp(argv[c], "-quiet")) {
+      quiet = 1;
+    } else if (!strcmp(argv[c], "-help") || !strcmp(argv[c], "-h")) {
+      printf("webp_quality [-h][-quiet] webp_files...\n");
+      FREE_WARGV_AND_RETURN(0);
+    } else {
+      const char* const filename = (const char*)GET_WARGV(argv, c);
+      const uint8_t* data = NULL;
+      size_t data_size = 0;
+      int q;
+      ok = ImgIoUtilReadFile(filename, &data, &data_size);
+      if (!ok) break;
+      q = VP8EstimateQuality(data, data_size);
+      if (!quiet) WPRINTF("[%s] ", (const W_CHAR*)filename);
+      if (q < 0) {
+        fprintf(stderr, "Not a WebP file, or not a lossy WebP file.\n");
+        ok = 0;
+      } else {
+        if (!quiet) {
+          printf("Estimated quality factor: %d\n", q);
+        } else {
+          printf("%d\n", q);   // just print the number
+        }
+      }
+      free((void*)data);
+    }
+  }
+  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+}
--- a/external/libwebp/libwebp/extras/webp_to_sdl.c
+++ b/external/libwebp/libwebp/extras/webp_to_sdl.c
@@ -0,0 +1,110 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Simple WebP-to-SDL wrapper. Useful for emscripten.
+//
+// Author: James Zern (jzern@google.com)
+
+#ifdef HAVE_CONFIG_H
+#include "src/webp/config.h"
+#endif
+
+#if defined(WEBP_HAVE_SDL)
+
+#include "webp_to_sdl.h"
+
+#include <stdio.h>
+#include "src/webp/decode.h"
+
+#if defined(WEBP_HAVE_JUST_SDL_H)
+#include <SDL.h>
+#else
+#include <SDL/SDL.h>
+#endif
+
+static int init_ok = 0;
+int WebPToSDL(const char* data, unsigned int data_size) {
+  int ok = 0;
+  VP8StatusCode status;
+  WebPDecoderConfig config;
+  WebPBitstreamFeatures* const input = &config.input;
+  WebPDecBuffer* const output = &config.output;
+  SDL_Surface* screen = NULL;
+  SDL_Surface* surface = NULL;
+
+  if (!WebPInitDecoderConfig(&config)) {
+    fprintf(stderr, "Library version mismatch!\n");
+    return 0;
+  }
+
+  if (!init_ok) {
+    SDL_Init(SDL_INIT_VIDEO);
+    init_ok = 1;
+  }
+
+  status = WebPGetFeatures((uint8_t*)data, (size_t)data_size, &config.input);
+  if (status != VP8_STATUS_OK) goto Error;
+
+  screen = SDL_SetVideoMode(input->width, input->height, 32, SDL_SWSURFACE);
+  if (screen == NULL) {
+    fprintf(stderr, "Unable to set video mode (32bpp %dx%d)!\n",
+            input->width, input->height);
+    goto Error;
+  }
+
+  surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
+                                 input->width, input->height, 32,
+                                 0x000000ffu,   // R mask
+                                 0x0000ff00u,   // G mask
+                                 0x00ff0000u,   // B mask
+                                 0xff000000u);  // A mask
+
+  if (surface == NULL) {
+    fprintf(stderr, "Unable to create %dx%d RGBA surface!\n",
+            input->width, input->height);
+    goto Error;
+  }
+  if (SDL_MUSTLOCK(surface)) SDL_LockSurface(surface);
+
+#if SDL_BYTEORDER == SDL_BIG_ENDIAN
+  output->colorspace = MODE_BGRA;
+#else
+  output->colorspace = MODE_RGBA;
+#endif
+  output->width  = surface->w;
+  output->height = surface->h;
+  output->u.RGBA.rgba   = surface->pixels;
+  output->u.RGBA.stride = surface->pitch;
+  output->u.RGBA.size   = surface->pitch * surface->h;
+  output->is_external_memory = 1;
+
+  status = WebPDecode((const uint8_t*)data, (size_t)data_size, &config);
+  if (status != VP8_STATUS_OK) {
+    fprintf(stderr, "Error decoding image (%d)\n", status);
+    goto Error;
+  }
+
+  if (SDL_MUSTLOCK(surface)) SDL_UnlockSurface(surface);
+  if (SDL_BlitSurface(surface, NULL, screen, NULL) ||
+      SDL_Flip(screen)) {
+    goto Error;
+  }
+
+  ok = 1;
+
+ Error:
+  SDL_FreeSurface(surface);
+  SDL_FreeSurface(screen);
+  WebPFreeDecBuffer(output);
+  return ok;
+}
+
+//------------------------------------------------------------------------------
+
+#endif  // WEBP_HAVE_SDL
--- a/external/libwebp/libwebp/extras/webp_to_sdl.h
+++ b/external/libwebp/libwebp/extras/webp_to_sdl.h
@@ -0,0 +1,22 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Simple WebP-to-SDL wrapper. Useful for emscripten.
+//
+// Author: James Zern (jzern@google.com)
+
+#ifndef WEBP_EXTRAS_WEBP_TO_SDL_H_
+#define WEBP_EXTRAS_WEBP_TO_SDL_H_
+
+// Exports the method WebPToSDL(const char* data, int data_size) which decodes
+// a WebP bitstream into an RGBA SDL surface.
+// Return false on failure.
+extern int WebPToSDL(const char* data, unsigned int data_size);
+
+#endif  // WEBP_EXTRAS_WEBP_TO_SDL_H_
--- a/external/libwebp/libwebp/gradle.properties
+++ b/external/libwebp/libwebp/gradle.properties
@@ -0,0 +1,14 @@
+# Project-wide Gradle settings.
+
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+
+# Versions for gradle
+BUILD_TOOLS_VERSION=23.0.3
+COMPILE_SDK_VERSION=23
+ANDROID_GRADLE_PLUGIN_VERSION=1.5.0
+GRADLE_DOWNLOAD_TASK_VERSION=2.1.0
--- a/external/libwebp/libwebp/gradle/wrapper/gradle-wrapper.jar
+++ b/external/libwebp/libwebp/gradle/wrapper/gradle-wrapper.jar
--- a/external/libwebp/libwebp/gradle/wrapper/gradle-wrapper.properties
+++ b/external/libwebp/libwebp/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.1.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
--- a/external/libwebp/libwebp/gradlew
+++ b/external/libwebp/libwebp/gradlew
@@ -0,0 +1,183 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"
--- a/external/libwebp/libwebp/gradlew.bat
+++ b/external/libwebp/libwebp/gradlew.bat
@@ -0,0 +1,100 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
--- a/external/libwebp/libwebp/imageio/Android.mk
+++ b/external/libwebp/libwebp/imageio/Android.mk
@@ -0,0 +1,57 @@
+# Ignore this file during non-NDK builds.
+ifdef NDK_ROOT
+LOCAL_PATH := $(call my-dir)
+
+################################################################################
+# libimageio_util
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    imageio_util.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/../src
+
+LOCAL_MODULE := imageio_util
+
+include $(BUILD_STATIC_LIBRARY)
+
+################################################################################
+# libimagedec
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    image_dec.c \
+    jpegdec.c \
+    metadata.c \
+    pngdec.c \
+    pnmdec.c \
+    tiffdec.c \
+    webpdec.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/../src
+LOCAL_STATIC_LIBRARIES := imageio_util
+
+LOCAL_MODULE := imagedec
+
+include $(BUILD_STATIC_LIBRARY)
+
+################################################################################
+# libimageenc
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    image_enc.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/../src
+LOCAL_STATIC_LIBRARIES := imageio_util
+
+LOCAL_MODULE := imageenc
+
+include $(BUILD_STATIC_LIBRARY)
+endif  # NDK_ROOT
--- a/external/libwebp/libwebp/imageio/Makefile.am
+++ b/external/libwebp/libwebp/imageio/Makefile.am
@@ -0,0 +1,32 @@
+AM_CPPFLAGS += -I$(top_builddir)/src -I$(top_srcdir)/src
+noinst_LTLIBRARIES =
+noinst_LTLIBRARIES += libimageio_util.la
+if BUILD_DEMUX
+  noinst_LTLIBRARIES += libimagedec.la
+endif
+noinst_LTLIBRARIES += libimageenc.la
+
+noinst_HEADERS =
+noinst_HEADERS += ../src/webp/decode.h
+noinst_HEADERS += ../src/webp/types.h
+
+libimageio_util_la_SOURCES =
+libimageio_util_la_SOURCES += imageio_util.c imageio_util.h
+
+libimagedec_la_SOURCES  =
+libimagedec_la_SOURCES += image_dec.c image_dec.h
+libimagedec_la_SOURCES += jpegdec.c jpegdec.h
+libimagedec_la_SOURCES += metadata.c metadata.h
+libimagedec_la_SOURCES += pngdec.c pngdec.h
+libimagedec_la_SOURCES += pnmdec.c pnmdec.h
+libimagedec_la_SOURCES += tiffdec.c tiffdec.h
+libimagedec_la_SOURCES += webpdec.c webpdec.h
+libimagedec_la_SOURCES += wicdec.c wicdec.h
+libimagedec_la_CPPFLAGS = $(JPEG_INCLUDES) $(PNG_INCLUDES) $(TIFF_INCLUDES)
+libimagedec_la_CPPFLAGS += $(AM_CPPFLAGS)
+libimagedec_la_LIBADD = ../src/demux/libwebpdemux.la
+
+libimageenc_la_SOURCES  =
+libimageenc_la_SOURCES += image_enc.c image_enc.h
+libimageenc_la_CPPFLAGS = $(JPEG_INCLUDES) $(PNG_INCLUDES) $(TIFF_INCLUDES)
+libimageenc_la_CPPFLAGS += $(AM_CPPFLAGS)
--- a/external/libwebp/libwebp/imageio/image_dec.c
+++ b/external/libwebp/libwebp/imageio/image_dec.c
@@ -0,0 +1,84 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Generic image-type guessing.
+
+#include "./image_dec.h"
+
+const char* WebPGetEnabledInputFileFormats(void) {
+  return "WebP"
+#ifdef WEBP_HAVE_JPEG
+         ", JPEG"
+#endif
+#ifdef WEBP_HAVE_PNG
+         ", PNG"
+#endif
+         ", PNM (PGM, PPM, PAM)"
+#ifdef WEBP_HAVE_TIFF
+         ", TIFF"
+#endif
+#ifdef HAVE_WINCODEC_H
+         ", Windows Imaging Component (WIC)"
+#endif
+         "";
+}
+
+static WEBP_INLINE uint32_t GetBE32(const uint8_t buf[]) {
+  return ((uint32_t)buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
+}
+
+WebPInputFileFormat WebPGuessImageType(const uint8_t* const data,
+                                       size_t data_size) {
+  WebPInputFileFormat format = WEBP_UNSUPPORTED_FORMAT;
+  if (data != NULL && data_size >= 12) {
+    const uint32_t magic1 = GetBE32(data + 0);
+    const uint32_t magic2 = GetBE32(data + 8);
+    if (magic1 == 0x89504E47U) {
+      format = WEBP_PNG_FORMAT;
+    } else if (magic1 >= 0xFFD8FF00U && magic1 <= 0xFFD8FFFFU) {
+      format = WEBP_JPEG_FORMAT;
+    } else if (magic1 == 0x49492A00 || magic1 == 0x4D4D002A) {
+      format = WEBP_TIFF_FORMAT;
+    } else if (magic1 == 0x52494646 && magic2 == 0x57454250) {
+      format = WEBP_WEBP_FORMAT;
+    } else if (((magic1 >> 24) & 0xff) == 'P') {
+      const int type = (magic1 >> 16) & 0xff;
+      // we only support 'P5 -> P7' for now.
+      if (type >= '5' && type <= '7') format = WEBP_PNM_FORMAT;
+    }
+  }
+  return format;
+}
+
+static int FailReader(const uint8_t* const data, size_t data_size,
+                      struct WebPPicture* const pic,
+                      int keep_alpha, struct Metadata* const metadata) {
+  (void)data;
+  (void)data_size;
+  (void)pic;
+  (void)keep_alpha;
+  (void)metadata;
+  return 0;
+}
+
+WebPImageReader WebPGetImageReader(WebPInputFileFormat format) {
+  switch (format) {
+    case WEBP_PNG_FORMAT: return ReadPNG;
+    case WEBP_JPEG_FORMAT: return ReadJPEG;
+    case WEBP_TIFF_FORMAT: return ReadTIFF;
+    case WEBP_WEBP_FORMAT: return ReadWebP;
+    case WEBP_PNM_FORMAT: return ReadPNM;
+    default: return FailReader;
+  }
+}
+
+WebPImageReader WebPGuessImageReader(const uint8_t* const data,
+                                     size_t data_size) {
+  return WebPGetImageReader(WebPGuessImageType(data, data_size));
+}
--- a/external/libwebp/libwebp/imageio/image_dec.h
+++ b/external/libwebp/libwebp/imageio/image_dec.h
@@ -0,0 +1,70 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  All-in-one library to decode PNG/JPEG/WebP/TIFF/WIC input images.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#ifndef WEBP_IMAGEIO_IMAGE_DEC_H_
+#define WEBP_IMAGEIO_IMAGE_DEC_H_
+
+#include "webp/types.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "./metadata.h"
+#include "./jpegdec.h"
+#include "./pngdec.h"
+#include "./pnmdec.h"
+#include "./tiffdec.h"
+#include "./webpdec.h"
+#include "./wicdec.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+  WEBP_PNG_FORMAT = 0,
+  WEBP_JPEG_FORMAT,
+  WEBP_TIFF_FORMAT,
+  WEBP_WEBP_FORMAT,
+  WEBP_PNM_FORMAT,
+  WEBP_UNSUPPORTED_FORMAT
+} WebPInputFileFormat;
+
+// Returns a comma separated list of enabled input formats.
+const char* WebPGetEnabledInputFileFormats(void);
+
+// Try to infer the image format. 'data_size' should be larger than 12.
+// Returns WEBP_UNSUPPORTED_FORMAT if format can't be guess safely.
+WebPInputFileFormat WebPGuessImageType(const uint8_t* const data,
+                                       size_t data_size);
+
+// Signature for common image-reading functions (ReadPNG, ReadJPEG, ...)
+typedef int (*WebPImageReader)(const uint8_t* const data, size_t data_size,
+                               struct WebPPicture* const pic,
+                               int keep_alpha, struct Metadata* const metadata);
+
+// Return the reader associated to a given file format.
+WebPImageReader WebPGetImageReader(WebPInputFileFormat format);
+
+// This function is similar to WebPGuessImageType(), but returns a
+// suitable reader function. The returned reader is never NULL, but
+// unknown formats will return an always-failing valid reader.
+WebPImageReader WebPGuessImageReader(const uint8_t* const data,
+                                     size_t data_size);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_IMAGE_DEC_H_
--- a/external/libwebp/libwebp/imageio/image_enc.c
+++ b/external/libwebp/libwebp/imageio/image_enc.c
@@ -0,0 +1,615 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Save image
+
+#include "./image_enc.h"
+
+#include <assert.h>
+#include <string.h>
+
+#ifdef WEBP_HAVE_PNG
+#include <png.h>
+#include <setjmp.h>   // note: this must be included *after* png.h
+#endif
+
+#ifdef HAVE_WINCODEC_H
+#ifdef __MINGW32__
+#define INITGUID  // Without this GUIDs are declared extern and fail to link
+#endif
+#define CINTERFACE
+#define COBJMACROS
+#define _WIN32_IE 0x500  // Workaround bug in shlwapi.h when compiling C++
+                         // code with COBJMACROS.
+#include <ole2.h>  // CreateStreamOnHGlobal()
+#include <shlwapi.h>
+#include <tchar.h>
+#include <windows.h>
+#include <wincodec.h>
+#endif
+
+#include "./imageio_util.h"
+#include "../examples/unicode.h"
+
+//------------------------------------------------------------------------------
+// PNG
+
+#ifdef HAVE_WINCODEC_H
+
+#define IFS(fn)                                                     \
+  do {                                                              \
+    if (SUCCEEDED(hr)) {                                            \
+      hr = (fn);                                                    \
+      if (FAILED(hr)) fprintf(stderr, #fn " failed %08lx\n", hr);   \
+    }                                                               \
+  } while (0)
+
+#ifdef __cplusplus
+#define MAKE_REFGUID(x) (x)
+#else
+#define MAKE_REFGUID(x) &(x)
+#endif
+
+static HRESULT CreateOutputStream(const char* out_file_name,
+                                  int write_to_mem, IStream** stream) {
+  HRESULT hr = S_OK;
+  if (write_to_mem) {
+    // Output to a memory buffer. This is freed when 'stream' is released.
+    IFS(CreateStreamOnHGlobal(NULL, TRUE, stream));
+  } else {
+    IFS(SHCreateStreamOnFile((const LPTSTR)out_file_name,
+                             STGM_WRITE | STGM_CREATE, stream));
+  }
+  if (FAILED(hr)) {
+    _ftprintf(stderr, _T("Error opening output file %s (%08lx)\n"),
+              (const LPTSTR)out_file_name, hr);
+  }
+  return hr;
+}
+
+static HRESULT WriteUsingWIC(const char* out_file_name, int use_stdout,
+                             REFGUID container_guid,
+                             uint8_t* rgb, int stride,
+                             uint32_t width, uint32_t height, int has_alpha) {
+  HRESULT hr = S_OK;
+  IWICImagingFactory* factory = NULL;
+  IWICBitmapFrameEncode* frame = NULL;
+  IWICBitmapEncoder* encoder = NULL;
+  IStream* stream = NULL;
+  WICPixelFormatGUID pixel_format = has_alpha ? GUID_WICPixelFormat32bppBGRA
+                                              : GUID_WICPixelFormat24bppBGR;
+
+  if (out_file_name == NULL || rgb == NULL) return E_INVALIDARG;
+
+  IFS(CoInitialize(NULL));
+  IFS(CoCreateInstance(MAKE_REFGUID(CLSID_WICImagingFactory), NULL,
+                       CLSCTX_INPROC_SERVER,
+                       MAKE_REFGUID(IID_IWICImagingFactory),
+                       (LPVOID*)&factory));
+  if (hr == REGDB_E_CLASSNOTREG) {
+    fprintf(stderr,
+            "Couldn't access Windows Imaging Component (are you running "
+            "Windows XP SP3 or newer?). PNG support not available. "
+            "Use -ppm or -pgm for available PPM and PGM formats.\n");
+  }
+  IFS(CreateOutputStream(out_file_name, use_stdout, &stream));
+  IFS(IWICImagingFactory_CreateEncoder(factory, container_guid, NULL,
+                                       &encoder));
+  IFS(IWICBitmapEncoder_Initialize(encoder, stream,
+                                   WICBitmapEncoderNoCache));
+  IFS(IWICBitmapEncoder_CreateNewFrame(encoder, &frame, NULL));
+  IFS(IWICBitmapFrameEncode_Initialize(frame, NULL));
+  IFS(IWICBitmapFrameEncode_SetSize(frame, width, height));
+  IFS(IWICBitmapFrameEncode_SetPixelFormat(frame, &pixel_format));
+  IFS(IWICBitmapFrameEncode_WritePixels(frame, height, stride,
+                                        height * stride, rgb));
+  IFS(IWICBitmapFrameEncode_Commit(frame));
+  IFS(IWICBitmapEncoder_Commit(encoder));
+
+  if (SUCCEEDED(hr) && use_stdout) {
+    HGLOBAL image;
+    IFS(GetHGlobalFromStream(stream, &image));
+    if (SUCCEEDED(hr)) {
+      HANDLE std_output = GetStdHandle(STD_OUTPUT_HANDLE);
+      DWORD mode;
+      const BOOL update_mode = GetConsoleMode(std_output, &mode);
+      const void* const image_mem = GlobalLock(image);
+      DWORD bytes_written = 0;
+
+      // Clear output processing if necessary, then output the image.
+      if (update_mode) SetConsoleMode(std_output, 0);
+      if (!WriteFile(std_output, image_mem, (DWORD)GlobalSize(image),
+                     &bytes_written, NULL) ||
+          bytes_written != GlobalSize(image)) {
+        hr = E_FAIL;
+      }
+      if (update_mode) SetConsoleMode(std_output, mode);
+      GlobalUnlock(image);
+    }
+  }
+
+  if (frame != NULL) IUnknown_Release(frame);
+  if (encoder != NULL) IUnknown_Release(encoder);
+  if (factory != NULL) IUnknown_Release(factory);
+  if (stream != NULL) IUnknown_Release(stream);
+  return hr;
+}
+
+int WebPWritePNG(const char* out_file_name, int use_stdout,
+                 const WebPDecBuffer* const buffer) {
+  const uint32_t width = buffer->width;
+  const uint32_t height = buffer->height;
+  uint8_t* const rgb = buffer->u.RGBA.rgba;
+  const int stride = buffer->u.RGBA.stride;
+  const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
+
+  return SUCCEEDED(WriteUsingWIC(out_file_name, use_stdout,
+                                 MAKE_REFGUID(GUID_ContainerFormatPng),
+                                 rgb, stride, width, height, has_alpha));
+}
+
+#elif defined(WEBP_HAVE_PNG)    // !HAVE_WINCODEC_H
+static void PNGAPI PNGErrorFunction(png_structp png, png_const_charp unused) {
+  (void)unused;  // remove variable-unused warning
+  longjmp(png_jmpbuf(png), 1);
+}
+
+int WebPWritePNG(FILE* out_file, const WebPDecBuffer* const buffer) {
+  volatile png_structp png;
+  volatile png_infop info;
+
+  if (out_file == NULL || buffer == NULL) return 0;
+
+  png = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+                                NULL, PNGErrorFunction, NULL);
+  if (png == NULL) {
+    return 0;
+  }
+  info = png_create_info_struct(png);
+  if (info == NULL) {
+    png_destroy_write_struct((png_structpp)&png, NULL);
+    return 0;
+  }
+  if (setjmp(png_jmpbuf(png))) {
+    png_destroy_write_struct((png_structpp)&png, (png_infopp)&info);
+    return 0;
+  }
+  png_init_io(png, out_file);
+  {
+    const uint32_t width = buffer->width;
+    const uint32_t height = buffer->height;
+    png_bytep row = buffer->u.RGBA.rgba;
+    const int stride = buffer->u.RGBA.stride;
+    const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
+    uint32_t y;
+
+    png_set_IHDR(png, info, width, height, 8,
+                 has_alpha ? PNG_COLOR_TYPE_RGBA : PNG_COLOR_TYPE_RGB,
+                 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
+                 PNG_FILTER_TYPE_DEFAULT);
+    png_write_info(png, info);
+    for (y = 0; y < height; ++y) {
+      png_write_rows(png, &row, 1);
+      row += stride;
+    }
+  }
+  png_write_end(png, info);
+  png_destroy_write_struct((png_structpp)&png, (png_infopp)&info);
+  return 1;
+}
+#else    // !HAVE_WINCODEC_H && !WEBP_HAVE_PNG
+int WebPWritePNG(FILE* fout, const WebPDecBuffer* const buffer) {
+  if (fout == NULL || buffer == NULL) return 0;
+
+  fprintf(stderr, "PNG support not compiled. Please install the libpng "
+          "development package before building.\n");
+  fprintf(stderr, "You can run with -ppm flag to decode in PPM format.\n");
+  return 0;
+}
+#endif
+
+//------------------------------------------------------------------------------
+// PPM / PAM
+
+static int WritePPMPAM(FILE* fout, const WebPDecBuffer* const buffer,
+                       int alpha) {
+  if (fout == NULL || buffer == NULL) {
+    return 0;
+  } else {
+    const uint32_t width = buffer->width;
+    const uint32_t height = buffer->height;
+    const uint8_t* row = buffer->u.RGBA.rgba;
+    const int stride = buffer->u.RGBA.stride;
+    const size_t bytes_per_px = alpha ? 4 : 3;
+    uint32_t y;
+
+    if (row == NULL) return 0;
+
+    if (alpha) {
+      fprintf(fout, "P7\nWIDTH %u\nHEIGHT %u\nDEPTH 4\nMAXVAL 255\n"
+                    "TUPLTYPE RGB_ALPHA\nENDHDR\n", width, height);
+    } else {
+      fprintf(fout, "P6\n%u %u\n255\n", width, height);
+    }
+    for (y = 0; y < height; ++y) {
+      if (fwrite(row, width, bytes_per_px, fout) != bytes_per_px) {
+        return 0;
+      }
+      row += stride;
+    }
+  }
+  return 1;
+}
+
+int WebPWritePPM(FILE* fout, const WebPDecBuffer* const buffer) {
+  return WritePPMPAM(fout, buffer, 0);
+}
+
+int WebPWritePAM(FILE* fout, const WebPDecBuffer* const buffer) {
+  return WritePPMPAM(fout, buffer, 1);
+}
+
+//------------------------------------------------------------------------------
+// Raw PGM
+
+// Save 16b mode (RGBA4444, RGB565, ...) for debugging purpose.
+int WebPWrite16bAsPGM(FILE* fout, const WebPDecBuffer* const buffer) {
+  const uint32_t width = buffer->width;
+  const uint32_t height = buffer->height;
+  const uint8_t* rgba = buffer->u.RGBA.rgba;
+  const int stride = buffer->u.RGBA.stride;
+  const uint32_t bytes_per_px = 2;
+  uint32_t y;
+
+  if (fout == NULL || buffer == NULL || rgba == NULL) return 0;
+
+  fprintf(fout, "P5\n%u %u\n255\n", width * bytes_per_px, height);
+  for (y = 0; y < height; ++y) {
+    if (fwrite(rgba, width, bytes_per_px, fout) != bytes_per_px) {
+      return 0;
+    }
+    rgba += stride;
+  }
+  return 1;
+}
+
+//------------------------------------------------------------------------------
+// BMP (see https://en.wikipedia.org/wiki/BMP_file_format#Pixel_storage)
+
+static void PutLE16(uint8_t* const dst, uint32_t value) {
+  dst[0] = (value >> 0) & 0xff;
+  dst[1] = (value >> 8) & 0xff;
+}
+
+static void PutLE32(uint8_t* const dst, uint32_t value) {
+  PutLE16(dst + 0, (value >>  0) & 0xffff);
+  PutLE16(dst + 2, (value >> 16) & 0xffff);
+}
+
+#define BMP_HEADER_SIZE 54
+#define BMP_HEADER_ALPHA_EXTRA_SIZE 16  // for alpha info
+int WebPWriteBMP(FILE* fout, const WebPDecBuffer* const buffer) {
+  const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
+  const int header_size =
+      BMP_HEADER_SIZE + (has_alpha ? BMP_HEADER_ALPHA_EXTRA_SIZE : 0);
+  const uint32_t width = buffer->width;
+  const uint32_t height = buffer->height;
+  const uint8_t* rgba = buffer->u.RGBA.rgba;
+  const int stride = buffer->u.RGBA.stride;
+  const uint32_t bytes_per_px = has_alpha ? 4 : 3;
+  uint32_t y;
+  const uint32_t line_size = bytes_per_px * width;
+  const uint32_t bmp_stride = (line_size + 3) & ~3;   // pad to 4
+  const uint32_t image_size = bmp_stride * height;
+  const uint32_t total_size =  image_size + header_size;
+  uint8_t bmp_header[BMP_HEADER_SIZE + BMP_HEADER_ALPHA_EXTRA_SIZE] = { 0 };
+
+  if (fout == NULL || buffer == NULL || rgba == NULL) return 0;
+
+  // bitmap file header
+  PutLE16(bmp_header + 0, 0x4d42);                // signature 'BM'
+  PutLE32(bmp_header + 2, total_size);            // size including header
+  PutLE32(bmp_header + 6, 0);                     // reserved
+  PutLE32(bmp_header + 10, header_size);          // offset to pixel array
+  // bitmap info header
+  PutLE32(bmp_header + 14, header_size - 14);     // DIB header size
+  PutLE32(bmp_header + 18, width);                // dimensions
+  PutLE32(bmp_header + 22, height);               // no vertical flip
+  PutLE16(bmp_header + 26, 1);                    // number of planes
+  PutLE16(bmp_header + 28, bytes_per_px * 8);     // bits per pixel
+  PutLE32(bmp_header + 30, has_alpha ? 3 : 0);    // BI_BITFIELDS or BI_RGB
+  PutLE32(bmp_header + 34, image_size);
+  PutLE32(bmp_header + 38, 2400);                 // x pixels/meter
+  PutLE32(bmp_header + 42, 2400);                 // y pixels/meter
+  PutLE32(bmp_header + 46, 0);                    // number of palette colors
+  PutLE32(bmp_header + 50, 0);                    // important color count
+  if (has_alpha) {  // BITMAPV3INFOHEADER complement
+    PutLE32(bmp_header + 54, 0x00ff0000);         // red mask
+    PutLE32(bmp_header + 58, 0x0000ff00);         // green mask
+    PutLE32(bmp_header + 62, 0x000000ff);         // blue mask
+    PutLE32(bmp_header + 66, 0xff000000);         // alpha mask
+  }
+
+  // TODO(skal): color profile
+
+  // write header
+  if (fwrite(bmp_header, header_size, 1, fout) != 1) {
+    return 0;
+  }
+
+  // write pixel array, bottom to top
+  for (y = 0; y < height; ++y) {
+    const uint8_t* const src = &rgba[(uint64_t)(height - 1 - y) * stride];
+    if (fwrite(src, line_size, 1, fout) != 1) {
+      return 0;
+    }
+    // write padding zeroes
+    if (bmp_stride != line_size) {
+      const uint8_t zeroes[3] = { 0 };
+      if (fwrite(zeroes, bmp_stride - line_size, 1, fout) != 1) {
+        return 0;
+      }
+    }
+  }
+  return 1;
+}
+#undef BMP_HEADER_SIZE
+#undef BMP_HEADER_ALPHA_EXTRA_SIZE
+
+//------------------------------------------------------------------------------
+// TIFF
+
+#define NUM_IFD_ENTRIES 15
+#define EXTRA_DATA_SIZE 16
+// 10b for signature/header + n * 12b entries + 4b for IFD terminator:
+#define EXTRA_DATA_OFFSET (10 + 12 * NUM_IFD_ENTRIES + 4)
+#define TIFF_HEADER_SIZE (EXTRA_DATA_OFFSET + EXTRA_DATA_SIZE)
+
+int WebPWriteTIFF(FILE* fout, const WebPDecBuffer* const buffer) {
+  const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
+  const uint32_t width = buffer->width;
+  const uint32_t height = buffer->height;
+  const uint8_t* rgba = buffer->u.RGBA.rgba;
+  const int stride = buffer->u.RGBA.stride;
+  const uint8_t bytes_per_px = has_alpha ? 4 : 3;
+  const uint8_t assoc_alpha =
+      WebPIsPremultipliedMode(buffer->colorspace) ? 1 : 2;
+  // For non-alpha case, we omit tag 0x152 (ExtraSamples).
+  const uint8_t num_ifd_entries = has_alpha ? NUM_IFD_ENTRIES
+                                            : NUM_IFD_ENTRIES - 1;
+  uint8_t tiff_header[TIFF_HEADER_SIZE] = {
+    0x49, 0x49, 0x2a, 0x00,   // little endian signature
+    8, 0, 0, 0,               // offset to the unique IFD that follows
+    // IFD (offset = 8). Entries must be written in increasing tag order.
+    num_ifd_entries, 0,       // Number of entries in the IFD (12 bytes each).
+    0x00, 0x01, 3, 0, 1, 0, 0, 0, 0, 0, 0, 0,    //  10: Width  (TBD)
+    0x01, 0x01, 3, 0, 1, 0, 0, 0, 0, 0, 0, 0,    //  22: Height (TBD)
+    0x02, 0x01, 3, 0, bytes_per_px, 0, 0, 0,     //  34: BitsPerSample: 8888
+        EXTRA_DATA_OFFSET + 0, 0, 0, 0,
+    0x03, 0x01, 3, 0, 1, 0, 0, 0, 1, 0, 0, 0,    //  46: Compression: none
+    0x06, 0x01, 3, 0, 1, 0, 0, 0, 2, 0, 0, 0,    //  58: Photometric: RGB
+    0x11, 0x01, 4, 0, 1, 0, 0, 0,                //  70: Strips offset:
+        TIFF_HEADER_SIZE, 0, 0, 0,               //      data follows header
+    0x12, 0x01, 3, 0, 1, 0, 0, 0, 1, 0, 0, 0,    //  82: Orientation: topleft
+    0x15, 0x01, 3, 0, 1, 0, 0, 0,                //  94: SamplesPerPixels
+        bytes_per_px, 0, 0, 0,
+    0x16, 0x01, 3, 0, 1, 0, 0, 0, 0, 0, 0, 0,    // 106: Rows per strip (TBD)
+    0x17, 0x01, 4, 0, 1, 0, 0, 0, 0, 0, 0, 0,    // 118: StripByteCount (TBD)
+    0x1a, 0x01, 5, 0, 1, 0, 0, 0,                // 130: X-resolution
+        EXTRA_DATA_OFFSET + 8, 0, 0, 0,
+    0x1b, 0x01, 5, 0, 1, 0, 0, 0,                // 142: Y-resolution
+        EXTRA_DATA_OFFSET + 8, 0, 0, 0,
+    0x1c, 0x01, 3, 0, 1, 0, 0, 0, 1, 0, 0, 0,    // 154: PlanarConfiguration
+    0x28, 0x01, 3, 0, 1, 0, 0, 0, 2, 0, 0, 0,    // 166: ResolutionUnit (inch)
+    0x52, 0x01, 3, 0, 1, 0, 0, 0,
+        assoc_alpha, 0, 0, 0,                    // 178: ExtraSamples: rgbA/RGBA
+    0, 0, 0, 0,                                  // 190: IFD terminator
+    // EXTRA_DATA_OFFSET:
+    8, 0, 8, 0, 8, 0, 8, 0,      // BitsPerSample
+    72, 0, 0, 0, 1, 0, 0, 0      // 72 pixels/inch, for X/Y-resolution
+  };
+  uint32_t y;
+
+  if (fout == NULL || buffer == NULL || rgba == NULL) return 0;
+
+  // Fill placeholders in IFD:
+  PutLE32(tiff_header + 10 + 8, width);
+  PutLE32(tiff_header + 22 + 8, height);
+  PutLE32(tiff_header + 106 + 8, height);
+  PutLE32(tiff_header + 118 + 8, width * bytes_per_px * height);
+  if (!has_alpha) PutLE32(tiff_header + 178, 0);  // IFD terminator
+
+  // write header
+  if (fwrite(tiff_header, sizeof(tiff_header), 1, fout) != 1) {
+    return 0;
+  }
+  // write pixel values
+  for (y = 0; y < height; ++y) {
+    if (fwrite(rgba, bytes_per_px, width, fout) != width) {
+      return 0;
+    }
+    rgba += stride;
+  }
+
+  return 1;
+}
+
+#undef TIFF_HEADER_SIZE
+#undef EXTRA_DATA_OFFSET
+#undef EXTRA_DATA_SIZE
+#undef NUM_IFD_ENTRIES
+
+//------------------------------------------------------------------------------
+// Raw Alpha
+
+int WebPWriteAlphaPlane(FILE* fout, const WebPDecBuffer* const buffer) {
+  if (fout == NULL || buffer == NULL) {
+    return 0;
+  } else {
+    const uint32_t width = buffer->width;
+    const uint32_t height = buffer->height;
+    const uint8_t* a = buffer->u.YUVA.a;
+    const int a_stride = buffer->u.YUVA.a_stride;
+    uint32_t y;
+
+    if (a == NULL) return 0;
+
+    fprintf(fout, "P5\n%u %u\n255\n", width, height);
+    for (y = 0; y < height; ++y) {
+      if (fwrite(a, width, 1, fout) != 1) return 0;
+      a += a_stride;
+    }
+    return 1;
+  }
+}
+
+//------------------------------------------------------------------------------
+// PGM with IMC4 layout
+
+int WebPWritePGM(FILE* fout, const WebPDecBuffer* const buffer) {
+  if (fout == NULL || buffer == NULL) {
+    return 0;
+  } else {
+    const int width = buffer->width;
+    const int height = buffer->height;
+    const WebPYUVABuffer* const yuv = &buffer->u.YUVA;
+    const uint8_t* src_y = yuv->y;
+    const uint8_t* src_u = yuv->u;
+    const uint8_t* src_v = yuv->v;
+    const uint8_t* src_a = yuv->a;
+    const int uv_width = (width + 1) / 2;
+    const int uv_height = (height + 1) / 2;
+    const int a_height = (src_a != NULL) ? height : 0;
+    int ok = 1;
+    int y;
+
+    if (src_y == NULL || src_u == NULL || src_v == NULL) return 0;
+
+    fprintf(fout, "P5\n%d %d\n255\n",
+            (width + 1) & ~1, height + uv_height + a_height);
+    for (y = 0; ok && y < height; ++y) {
+      ok &= (fwrite(src_y, width, 1, fout) == 1);
+      if (width & 1) fputc(0, fout);    // padding byte
+      src_y += yuv->y_stride;
+    }
+    for (y = 0; ok && y < uv_height; ++y) {
+      ok &= (fwrite(src_u, uv_width, 1, fout) == 1);
+      ok &= (fwrite(src_v, uv_width, 1, fout) == 1);
+      src_u += yuv->u_stride;
+      src_v += yuv->v_stride;
+    }
+    for (y = 0; ok && y < a_height; ++y) {
+      ok &= (fwrite(src_a, width, 1, fout) == 1);
+      if (width & 1) fputc(0, fout);    // padding byte
+      src_a += yuv->a_stride;
+    }
+    return ok;
+  }
+}
+
+//------------------------------------------------------------------------------
+// Raw YUV(A) planes
+
+int WebPWriteYUV(FILE* fout, const WebPDecBuffer* const buffer) {
+  if (fout == NULL || buffer == NULL) {
+    return 0;
+  } else {
+    const int width = buffer->width;
+    const int height = buffer->height;
+    const WebPYUVABuffer* const yuv = &buffer->u.YUVA;
+    const uint8_t* src_y = yuv->y;
+    const uint8_t* src_u = yuv->u;
+    const uint8_t* src_v = yuv->v;
+    const uint8_t* src_a = yuv->a;
+    const int uv_width = (width + 1) / 2;
+    const int uv_height = (height + 1) / 2;
+    const int a_height = (src_a != NULL) ? height : 0;
+    int ok = 1;
+    int y;
+
+    if (src_y == NULL || src_u == NULL || src_v == NULL) return 0;
+
+    for (y = 0; ok && y < height; ++y) {
+      ok &= (fwrite(src_y, width, 1, fout) == 1);
+      src_y += yuv->y_stride;
+    }
+    for (y = 0; ok && y < uv_height; ++y) {
+      ok &= (fwrite(src_u, uv_width, 1, fout) == 1);
+      src_u += yuv->u_stride;
+    }
+    for (y = 0; ok && y < uv_height; ++y) {
+      ok &= (fwrite(src_v, uv_width, 1, fout) == 1);
+      src_v += yuv->v_stride;
+    }
+    for (y = 0; ok && y < a_height; ++y) {
+      ok &= (fwrite(src_a, width, 1, fout) == 1);
+      src_a += yuv->a_stride;
+    }
+    return ok;
+  }
+}
+
+//------------------------------------------------------------------------------
+// Generic top-level call
+
+int WebPSaveImage(const WebPDecBuffer* const buffer,
+                  WebPOutputFileFormat format,
+                  const char* const out_file_name) {
+  FILE* fout = NULL;
+  int needs_open_file = 1;
+  const int use_stdout =
+      (out_file_name != NULL) && !WSTRCMP(out_file_name, "-");
+  int ok = 1;
+
+  if (buffer == NULL || out_file_name == NULL) return 0;
+
+#ifdef HAVE_WINCODEC_H
+  needs_open_file = (format != PNG);
+#endif
+
+  if (needs_open_file) {
+    fout = use_stdout ? ImgIoUtilSetBinaryMode(stdout)
+                      : WFOPEN(out_file_name, "wb");
+    if (fout == NULL) {
+      WFPRINTF(stderr, "Error opening output file %s\n",
+               (const W_CHAR*)out_file_name);
+      return 0;
+    }
+  }
+
+  if (format == PNG ||
+      format == RGBA || format == BGRA || format == ARGB ||
+      format == rgbA || format == bgrA || format == Argb) {
+#ifdef HAVE_WINCODEC_H
+    ok &= WebPWritePNG(out_file_name, use_stdout, buffer);
+#else
+    ok &= WebPWritePNG(fout, buffer);
+#endif
+  } else if (format == PAM) {
+    ok &= WebPWritePAM(fout, buffer);
+  } else if (format == PPM || format == RGB || format == BGR) {
+    ok &= WebPWritePPM(fout, buffer);
+  } else if (format == RGBA_4444 || format == RGB_565 || format == rgbA_4444) {
+    ok &= WebPWrite16bAsPGM(fout, buffer);
+  } else if (format == BMP) {
+    ok &= WebPWriteBMP(fout, buffer);
+  } else if (format == TIFF) {
+    ok &= WebPWriteTIFF(fout, buffer);
+  } else if (format == RAW_YUV) {
+    ok &= WebPWriteYUV(fout, buffer);
+  } else if (format == PGM || format == YUV || format == YUVA) {
+    ok &= WebPWritePGM(fout, buffer);
+  } else if (format == ALPHA_PLANE_ONLY) {
+    ok &= WebPWriteAlphaPlane(fout, buffer);
+  }
+  if (fout != NULL && fout != stdout) {
+    fclose(fout);
+  }
+  return ok;
+}
--- a/external/libwebp/libwebp/imageio/image_enc.h
+++ b/external/libwebp/libwebp/imageio/image_enc.h
@@ -0,0 +1,96 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  All-in-one library to save PNG/JPEG/WebP/TIFF/WIC images.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#ifndef WEBP_IMAGEIO_IMAGE_ENC_H_
+#define WEBP_IMAGEIO_IMAGE_ENC_H_
+
+#include <stdio.h>
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "webp/types.h"
+#include "webp/decode.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Output types
+typedef enum {
+  PNG = 0,
+  PAM,
+  PPM,
+  PGM,
+  BMP,
+  TIFF,
+  RAW_YUV,
+  ALPHA_PLANE_ONLY,  // this is for experimenting only
+  // forced colorspace output (for testing, mostly)
+  RGB, RGBA, BGR, BGRA, ARGB,
+  RGBA_4444, RGB_565,
+  rgbA, bgrA, Argb, rgbA_4444,
+  YUV, YUVA
+} WebPOutputFileFormat;
+
+// General all-purpose call.
+// Most formats expect a 'buffer' containing RGBA-like samples, except
+// RAW_YUV, YUV and YUVA formats.
+// If 'out_file_name' is "-", data is saved to stdout.
+// Returns false if an error occurred, true otherwise.
+int WebPSaveImage(const WebPDecBuffer* const buffer,
+                  WebPOutputFileFormat format, const char* const out_file_name);
+
+// Save to PNG.
+#ifdef HAVE_WINCODEC_H
+int WebPWritePNG(const char* out_file_name, int use_stdout,
+                 const struct WebPDecBuffer* const buffer);
+#else
+int WebPWritePNG(FILE* out_file, const WebPDecBuffer* const buffer);
+#endif
+
+// Save to PPM format (RGB, no alpha)
+int WebPWritePPM(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save to PAM format (= PPM + alpha)
+int WebPWritePAM(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save 16b mode (RGBA4444, RGB565, ...) for debugging purposes.
+int WebPWrite16bAsPGM(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save as BMP
+int WebPWriteBMP(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save as TIFF
+int WebPWriteTIFF(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save the ALPHA plane (only) as a PGM
+int WebPWriteAlphaPlane(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save as YUV samples as PGM format (using IMC4 layout).
+// See: https://www.fourcc.org/yuv.php#IMC4.
+// (very convenient format for viewing the samples, esp. for odd dimensions).
+int WebPWritePGM(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save YUV(A) planes sequentially (raw dump)
+int WebPWriteYUV(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+// Save 16b mode (RGBA4444, RGB565, ...) as PGM format, for debugging purposes.
+int WebPWrite16bAsPGM(FILE* fout, const struct WebPDecBuffer* const buffer);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_IMAGE_ENC_H_
--- a/external/libwebp/libwebp/imageio/imageio_util.c
+++ b/external/libwebp/libwebp/imageio/imageio_util.c
@@ -0,0 +1,162 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Utility functions used by the image decoders.
+//
+
+#include "./imageio_util.h"
+
+#if defined(_WIN32)
+#include <fcntl.h>   // for _O_BINARY
+#include <io.h>      // for _setmode()
+#endif
+#include <stdlib.h>
+#include <string.h>
+#include "../examples/unicode.h"
+
+// -----------------------------------------------------------------------------
+// File I/O
+
+FILE* ImgIoUtilSetBinaryMode(FILE* file) {
+#if defined(_WIN32)
+  if (_setmode(_fileno(file), _O_BINARY) == -1) {
+    fprintf(stderr, "Failed to reopen file in O_BINARY mode.\n");
+    return NULL;
+  }
+#endif
+  return file;
+}
+
+int ImgIoUtilReadFromStdin(const uint8_t** data, size_t* data_size) {
+  static const size_t kBlockSize = 16384;  // default initial size
+  size_t max_size = 0;
+  size_t size = 0;
+  uint8_t* input = NULL;
+
+  if (data == NULL || data_size == NULL) return 0;
+  *data = NULL;
+  *data_size = 0;
+
+  if (!ImgIoUtilSetBinaryMode(stdin)) return 0;
+
+  while (!feof(stdin)) {
+    // We double the buffer size each time and read as much as possible.
+    const size_t extra_size = (max_size == 0) ? kBlockSize : max_size;
+    // we allocate one extra byte for the \0 terminator
+    void* const new_data = realloc(input, max_size + extra_size + 1);
+    if (new_data == NULL) goto Error;
+    input = (uint8_t*)new_data;
+    max_size += extra_size;
+    size += fread(input + size, 1, extra_size, stdin);
+    if (size < max_size) break;
+  }
+  if (ferror(stdin)) goto Error;
+  if (input != NULL) input[size] = '\0';  // convenient 0-terminator
+  *data = input;
+  *data_size = size;
+  return 1;
+
+ Error:
+  free(input);
+  fprintf(stderr, "Could not read from stdin\n");
+  return 0;
+}
+
+int ImgIoUtilReadFile(const char* const file_name,
+                      const uint8_t** data, size_t* data_size) {
+  int ok;
+  uint8_t* file_data;
+  size_t file_size;
+  FILE* in;
+  const int from_stdin = (file_name == NULL) || !WSTRCMP(file_name, "-");
+
+  if (from_stdin) return ImgIoUtilReadFromStdin(data, data_size);
+
+  if (data == NULL || data_size == NULL) return 0;
+  *data = NULL;
+  *data_size = 0;
+
+  in = WFOPEN(file_name, "rb");
+  if (in == NULL) {
+    WFPRINTF(stderr, "cannot open input file '%s'\n", (const W_CHAR*)file_name);
+    return 0;
+  }
+  fseek(in, 0, SEEK_END);
+  file_size = ftell(in);
+  fseek(in, 0, SEEK_SET);
+  // we allocate one extra byte for the \0 terminator
+  file_data = (uint8_t*)WebPMalloc(file_size + 1);
+  if (file_data == NULL) {
+    fclose(in);
+    WFPRINTF(stderr, "memory allocation failure when reading file %s\n",
+             (const W_CHAR*)file_name);
+    return 0;
+  }
+  ok = (fread(file_data, file_size, 1, in) == 1);
+  fclose(in);
+
+  if (!ok) {
+    WFPRINTF(stderr, "Could not read %d bytes of data from file %s\n",
+             (int)file_size, (const W_CHAR*)file_name);
+    WebPFree(file_data);
+    return 0;
+  }
+  file_data[file_size] = '\0';  // convenient 0-terminator
+  *data = file_data;
+  *data_size = file_size;
+  return 1;
+}
+
+// -----------------------------------------------------------------------------
+
+int ImgIoUtilWriteFile(const char* const file_name,
+                       const uint8_t* data, size_t data_size) {
+  int ok;
+  FILE* out;
+  const int to_stdout = (file_name == NULL) || !WSTRCMP(file_name, "-");
+
+  if (data == NULL) {
+    return 0;
+  }
+  out = to_stdout ? ImgIoUtilSetBinaryMode(stdout) : WFOPEN(file_name, "wb");
+  if (out == NULL) {
+    WFPRINTF(stderr, "Error! Cannot open output file '%s'\n",
+             (const W_CHAR*)file_name);
+    return 0;
+  }
+  ok = (fwrite(data, data_size, 1, out) == 1);
+  if (out != stdout) fclose(out);
+  return ok;
+}
+
+// -----------------------------------------------------------------------------
+
+void ImgIoUtilCopyPlane(const uint8_t* src, int src_stride,
+                        uint8_t* dst, int dst_stride, int width, int height) {
+  while (height-- > 0) {
+    memcpy(dst, src, width * sizeof(*dst));
+    src += src_stride;
+    dst += dst_stride;
+  }
+}
+
+// -----------------------------------------------------------------------------
+
+int ImgIoUtilCheckSizeArgumentsOverflow(uint64_t stride, size_t height) {
+  const uint64_t total_size = stride * height;
+  int ok = (total_size == (size_t)total_size);
+  // check that 'stride' is representable as int:
+  ok = ok && ((uint64_t)(int)stride == stride);
+#if defined(WEBP_MAX_IMAGE_SIZE)
+  ok = ok && (total_size <= (uint64_t)WEBP_MAX_IMAGE_SIZE);
+#endif
+  return ok;
+}
+
+// -----------------------------------------------------------------------------
--- a/external/libwebp/libwebp/imageio/imageio_util.h
+++ b/external/libwebp/libwebp/imageio/imageio_util.h
@@ -0,0 +1,64 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Utility functions used by the image decoders.
+//
+
+#ifndef WEBP_IMAGEIO_IMAGEIO_UTIL_H_
+#define WEBP_IMAGEIO_IMAGEIO_UTIL_H_
+
+#include <stdio.h>
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+//------------------------------------------------------------------------------
+// File I/O
+
+// Reopen file in binary (O_BINARY) mode.
+// Returns 'file' on success, NULL otherwise.
+FILE* ImgIoUtilSetBinaryMode(FILE* file);
+
+// Allocates storage for entire file 'file_name' and returns contents and size
+// in 'data' and 'data_size'. Returns 1 on success, 0 otherwise. '*data' should
+// be deleted using WebPFree().
+// Note: for convenience, the data will be null-terminated with an extra byte
+// (not accounted for in *data_size), in case the file is text and intended
+// to be used as a C-string.
+// If 'file_name' is NULL or equal to "-", input is read from stdin by calling
+// the function ImgIoUtilReadFromStdin().
+int ImgIoUtilReadFile(const char* const file_name,
+                      const uint8_t** data, size_t* data_size);
+
+// Same as ImgIoUtilReadFile(), but reads until EOF from stdin instead.
+int ImgIoUtilReadFromStdin(const uint8_t** data, size_t* data_size);
+
+// Write a data segment into a file named 'file_name'. Returns true if ok.
+// If 'file_name' is NULL or equal to "-", output is written to stdout.
+int ImgIoUtilWriteFile(const char* const file_name,
+                       const uint8_t* data, size_t data_size);
+
+//------------------------------------------------------------------------------
+
+// Copy width x height pixels from 'src' to 'dst' honoring the strides.
+void ImgIoUtilCopyPlane(const uint8_t* src, int src_stride,
+                        uint8_t* dst, int dst_stride, int width, int height);
+
+//------------------------------------------------------------------------------
+
+// Returns 0 in case of overflow, memory over-allocation or excessive dimension.
+int ImgIoUtilCheckSizeArgumentsOverflow(uint64_t stride, size_t height);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_IMAGEIO_UTIL_H_
--- a/external/libwebp/libwebp/imageio/jpegdec.c
+++ b/external/libwebp/libwebp/imageio/jpegdec.c
@@ -0,0 +1,364 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// JPEG decode.
+
+#include "./jpegdec.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include <stdio.h>
+
+#ifdef WEBP_HAVE_JPEG
+#include <jpeglib.h>
+#include <jerror.h>
+#include <setjmp.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/encode.h"
+#include "./imageio_util.h"
+#include "./metadata.h"
+
+// -----------------------------------------------------------------------------
+// Metadata processing
+
+#ifndef JPEG_APP1
+# define JPEG_APP1 (JPEG_APP0 + 1)
+#endif
+#ifndef JPEG_APP2
+# define JPEG_APP2 (JPEG_APP0 + 2)
+#endif
+
+typedef struct {
+  const uint8_t* data;
+  size_t data_length;
+  int seq;  // this segment's sequence number [1, 255] for use in reassembly.
+} ICCPSegment;
+
+static void SaveMetadataMarkers(j_decompress_ptr dinfo) {
+  const unsigned int max_marker_length = 0xffff;
+  jpeg_save_markers(dinfo, JPEG_APP1, max_marker_length);  // Exif/XMP
+  jpeg_save_markers(dinfo, JPEG_APP2, max_marker_length);  // ICC profile
+}
+
+static int CompareICCPSegments(const void* a, const void* b) {
+  const ICCPSegment* s1 = (const ICCPSegment*)a;
+  const ICCPSegment* s2 = (const ICCPSegment*)b;
+  return s1->seq - s2->seq;
+}
+
+// Extract ICC profile segments from the marker list in 'dinfo', reassembling
+// and storing them in 'iccp'.
+// Returns true on success and false for memory errors and corrupt profiles.
+static int StoreICCP(j_decompress_ptr dinfo, MetadataPayload* const iccp) {
+  // ICC.1:2010-12 (4.3.0.0) Annex B.4 Embedding ICC Profiles in JPEG files
+  static const char kICCPSignature[] = "ICC_PROFILE";
+  static const size_t kICCPSignatureLength = 12;  // signature includes '\0'
+  static const size_t kICCPSkipLength = 14;  // signature + seq & count
+  int expected_count = 0;
+  int actual_count = 0;
+  int seq_max = 0;
+  size_t total_size = 0;
+  ICCPSegment iccp_segments[255];
+  jpeg_saved_marker_ptr marker;
+
+  memset(iccp_segments, 0, sizeof(iccp_segments));
+  for (marker = dinfo->marker_list; marker != NULL; marker = marker->next) {
+    if (marker->marker == JPEG_APP2 &&
+        marker->data_length > kICCPSkipLength &&
+        !memcmp(marker->data, kICCPSignature, kICCPSignatureLength)) {
+      // ICC_PROFILE\0<seq><count>; 'seq' starts at 1.
+      const int seq = marker->data[kICCPSignatureLength];
+      const int count = marker->data[kICCPSignatureLength + 1];
+      const size_t segment_size = marker->data_length - kICCPSkipLength;
+      ICCPSegment* segment;
+
+      if (segment_size == 0 || count == 0 || seq == 0) {
+        fprintf(stderr, "[ICCP] size (%d) / count (%d) / sequence number (%d)"
+                        " cannot be 0!\n",
+                (int)segment_size, seq, count);
+        return 0;
+      }
+
+      if (expected_count == 0) {
+        expected_count = count;
+      } else if (expected_count != count) {
+        fprintf(stderr, "[ICCP] Inconsistent segment count (%d / %d)!\n",
+                expected_count, count);
+        return 0;
+      }
+
+      segment = iccp_segments + seq - 1;
+      if (segment->data_length != 0) {
+        fprintf(stderr, "[ICCP] Duplicate segment number (%d)!\n" , seq);
+        return 0;
+      }
+
+      segment->data = marker->data + kICCPSkipLength;
+      segment->data_length = segment_size;
+      segment->seq = seq;
+      total_size += segment_size;
+      if (seq > seq_max) seq_max = seq;
+      ++actual_count;
+    }
+  }
+
+  if (actual_count == 0) return 1;
+  if (seq_max != actual_count) {
+    fprintf(stderr, "[ICCP] Discontinuous segments, expected: %d actual: %d!\n",
+            actual_count, seq_max);
+    return 0;
+  }
+  if (expected_count != actual_count) {
+    fprintf(stderr, "[ICCP] Segment count: %d does not match expected: %d!\n",
+            actual_count, expected_count);
+    return 0;
+  }
+
+  // The segments may appear out of order in the file, sort them based on
+  // sequence number before assembling the payload.
+  qsort(iccp_segments, actual_count, sizeof(*iccp_segments),
+        CompareICCPSegments);
+
+  iccp->bytes = (uint8_t*)malloc(total_size);
+  if (iccp->bytes == NULL) return 0;
+  iccp->size = total_size;
+
+  {
+    int i;
+    size_t offset = 0;
+    for (i = 0; i < seq_max; ++i) {
+      memcpy(iccp->bytes + offset,
+             iccp_segments[i].data, iccp_segments[i].data_length);
+      offset += iccp_segments[i].data_length;
+    }
+  }
+  return 1;
+}
+
+// Returns true on success and false for memory errors and corrupt profiles.
+// The caller must use MetadataFree() on 'metadata' in all cases.
+static int ExtractMetadataFromJPEG(j_decompress_ptr dinfo,
+                                   Metadata* const metadata) {
+  static const struct {
+    int marker;
+    const char* signature;
+    size_t signature_length;
+    size_t storage_offset;
+  } kJPEGMetadataMap[] = {
+    // Exif 2.2 Section 4.7.2 Interoperability Structure of APP1 ...
+    { JPEG_APP1, "Exif\0",                        6, METADATA_OFFSET(exif) },
+    // XMP Specification Part 3 Section 3 Embedding XMP Metadata ... #JPEG
+    // TODO(jzern) Add support for 'ExtendedXMP'
+    { JPEG_APP1, "http://ns.adobe.com/xap/1.0/", 29, METADATA_OFFSET(xmp) },
+    { 0, NULL, 0, 0 },
+  };
+  jpeg_saved_marker_ptr marker;
+  // Treat ICC profiles separately as they may be segmented and out of order.
+  if (!StoreICCP(dinfo, &metadata->iccp)) return 0;
+
+  for (marker = dinfo->marker_list; marker != NULL; marker = marker->next) {
+    int i;
+    for (i = 0; kJPEGMetadataMap[i].marker != 0; ++i) {
+      if (marker->marker == kJPEGMetadataMap[i].marker &&
+          marker->data_length > kJPEGMetadataMap[i].signature_length &&
+          !memcmp(marker->data, kJPEGMetadataMap[i].signature,
+                  kJPEGMetadataMap[i].signature_length)) {
+        MetadataPayload* const payload =
+            (MetadataPayload*)((uint8_t*)metadata +
+                               kJPEGMetadataMap[i].storage_offset);
+
+        if (payload->bytes == NULL) {
+          const char* marker_data = (const char*)marker->data +
+                                    kJPEGMetadataMap[i].signature_length;
+          const size_t marker_data_length =
+              marker->data_length - kJPEGMetadataMap[i].signature_length;
+          if (!MetadataCopy(marker_data, marker_data_length, payload)) return 0;
+        } else {
+          fprintf(stderr, "Ignoring additional '%s' marker\n",
+                  kJPEGMetadataMap[i].signature);
+        }
+      }
+    }
+  }
+  return 1;
+}
+
+#undef JPEG_APP1
+#undef JPEG_APP2
+
+// -----------------------------------------------------------------------------
+// JPEG decoding
+
+struct my_error_mgr {
+  struct jpeg_error_mgr pub;
+  jmp_buf setjmp_buffer;
+};
+
+static void my_error_exit(j_common_ptr dinfo) {
+  struct my_error_mgr* myerr = (struct my_error_mgr*)dinfo->err;
+  fprintf(stderr, "libjpeg error: ");
+  dinfo->err->output_message(dinfo);
+  longjmp(myerr->setjmp_buffer, 1);
+}
+
+typedef struct {
+  struct jpeg_source_mgr pub;
+  const uint8_t* data;
+  size_t data_size;
+} JPEGReadContext;
+
+static void ContextInit(j_decompress_ptr cinfo) {
+  JPEGReadContext* const ctx = (JPEGReadContext*)cinfo->src;
+  ctx->pub.next_input_byte = ctx->data;
+  ctx->pub.bytes_in_buffer = ctx->data_size;
+}
+
+static boolean ContextFill(j_decompress_ptr cinfo) {
+  // we shouldn't get here.
+  ERREXIT(cinfo, JERR_FILE_READ);
+  return FALSE;
+}
+
+static void ContextSkip(j_decompress_ptr cinfo, long jump_size) {
+  JPEGReadContext* const ctx = (JPEGReadContext*)cinfo->src;
+  size_t jump = (size_t)jump_size;
+  if (jump > ctx->pub.bytes_in_buffer) {  // Don't overflow the buffer.
+    jump = ctx->pub.bytes_in_buffer;
+  }
+  ctx->pub.bytes_in_buffer -= jump;
+  ctx->pub.next_input_byte += jump;
+}
+
+static void ContextTerm(j_decompress_ptr cinfo) {
+  (void)cinfo;
+}
+
+static void ContextSetup(volatile struct jpeg_decompress_struct* const cinfo,
+                         JPEGReadContext* const ctx) {
+  cinfo->src = (struct jpeg_source_mgr*)ctx;
+  ctx->pub.init_source = ContextInit;
+  ctx->pub.fill_input_buffer = ContextFill;
+  ctx->pub.skip_input_data = ContextSkip;
+  ctx->pub.resync_to_restart = jpeg_resync_to_restart;
+  ctx->pub.term_source = ContextTerm;
+  ctx->pub.bytes_in_buffer = 0;
+  ctx->pub.next_input_byte = NULL;
+}
+
+int ReadJPEG(const uint8_t* const data, size_t data_size,
+             WebPPicture* const pic, int keep_alpha,
+             Metadata* const metadata) {
+  volatile int ok = 0;
+  int width, height;
+  int64_t stride;
+  volatile struct jpeg_decompress_struct dinfo;
+  struct my_error_mgr jerr;
+  uint8_t* volatile rgb = NULL;
+  JSAMPROW buffer[1];
+  JPEGReadContext ctx;
+
+  if (data == NULL || data_size == 0 || pic == NULL) return 0;
+
+  (void)keep_alpha;
+  memset(&ctx, 0, sizeof(ctx));
+  ctx.data = data;
+  ctx.data_size = data_size;
+
+  memset((j_decompress_ptr)&dinfo, 0, sizeof(dinfo));   // for setjmp safety
+  dinfo.err = jpeg_std_error(&jerr.pub);
+  jerr.pub.error_exit = my_error_exit;
+
+  if (setjmp(jerr.setjmp_buffer)) {
+ Error:
+    MetadataFree(metadata);
+    jpeg_destroy_decompress((j_decompress_ptr)&dinfo);
+    goto End;
+  }
+
+  jpeg_create_decompress((j_decompress_ptr)&dinfo);
+  ContextSetup(&dinfo, &ctx);
+  if (metadata != NULL) SaveMetadataMarkers((j_decompress_ptr)&dinfo);
+  jpeg_read_header((j_decompress_ptr)&dinfo, TRUE);
+
+  dinfo.out_color_space = JCS_RGB;
+  dinfo.do_fancy_upsampling = TRUE;
+
+  jpeg_start_decompress((j_decompress_ptr)&dinfo);
+
+  if (dinfo.output_components != 3) {
+    goto Error;
+  }
+
+  width = dinfo.output_width;
+  height = dinfo.output_height;
+  stride = (int64_t)dinfo.output_width * dinfo.output_components * sizeof(*rgb);
+
+  if (stride != (int)stride ||
+      !ImgIoUtilCheckSizeArgumentsOverflow(stride, height)) {
+    goto Error;
+  }
+
+  rgb = (uint8_t*)malloc((size_t)stride * height);
+  if (rgb == NULL) {
+    goto Error;
+  }
+  buffer[0] = (JSAMPLE*)rgb;
+
+  while (dinfo.output_scanline < dinfo.output_height) {
+    if (jpeg_read_scanlines((j_decompress_ptr)&dinfo, buffer, 1) != 1) {
+      goto Error;
+    }
+    buffer[0] += stride;
+  }
+
+  if (metadata != NULL) {
+    ok = ExtractMetadataFromJPEG((j_decompress_ptr)&dinfo, metadata);
+    if (!ok) {
+      fprintf(stderr, "Error extracting JPEG metadata!\n");
+      goto Error;
+    }
+  }
+
+  jpeg_finish_decompress((j_decompress_ptr)&dinfo);
+  jpeg_destroy_decompress((j_decompress_ptr)&dinfo);
+
+  // WebP conversion.
+  pic->width = width;
+  pic->height = height;
+  ok = WebPPictureImportRGB(pic, rgb, (int)stride);
+  if (!ok) {
+    pic->width = 0;   // WebPPictureImportRGB() barely touches 'pic' on failure.
+    pic->height = 0;  // Just reset dimensions but keep any 'custom_ptr' etc.
+    MetadataFree(metadata);  // In case the caller forgets to free it on error.
+  }
+
+ End:
+  free(rgb);
+  return ok;
+}
+#else  // !WEBP_HAVE_JPEG
+int ReadJPEG(const uint8_t* const data, size_t data_size,
+             struct WebPPicture* const pic, int keep_alpha,
+             struct Metadata* const metadata) {
+  (void)data;
+  (void)data_size;
+  (void)pic;
+  (void)keep_alpha;
+  (void)metadata;
+  fprintf(stderr, "JPEG support not compiled. Please install the libjpeg "
+          "development package before building.\n");
+  return 0;
+}
+#endif  // WEBP_HAVE_JPEG
+
+// -----------------------------------------------------------------------------
--- a/external/libwebp/libwebp/imageio/jpegdec.h
+++ b/external/libwebp/libwebp/imageio/jpegdec.h
@@ -0,0 +1,37 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// JPEG decode.
+
+#ifndef WEBP_IMAGEIO_JPEGDEC_H_
+#define WEBP_IMAGEIO_JPEGDEC_H_
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+// Reads a JPEG from 'data', returning the decoded output in 'pic'.
+// The output is RGB or YUV depending on pic->use_argb value.
+// Returns true on success.
+// 'keep_alpha' has no effect, but is kept for coherence with other signatures
+// for image readers.
+int ReadJPEG(const uint8_t* const data, size_t data_size,
+             struct WebPPicture* const pic, int keep_alpha,
+             struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_JPEGDEC_H_
--- a/external/libwebp/libwebp/imageio/metadata.c
+++ b/external/libwebp/libwebp/imageio/metadata.c
@@ -0,0 +1,49 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Metadata types and functions.
+//
+
+#include "./metadata.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/types.h"
+
+void MetadataInit(Metadata* const metadata) {
+  if (metadata == NULL) return;
+  memset(metadata, 0, sizeof(*metadata));
+}
+
+void MetadataPayloadDelete(MetadataPayload* const payload) {
+  if (payload == NULL) return;
+  free(payload->bytes);
+  payload->bytes = NULL;
+  payload->size = 0;
+}
+
+void MetadataFree(Metadata* const metadata) {
+  if (metadata == NULL) return;
+  MetadataPayloadDelete(&metadata->exif);
+  MetadataPayloadDelete(&metadata->iccp);
+  MetadataPayloadDelete(&metadata->xmp);
+}
+
+int MetadataCopy(const char* metadata, size_t metadata_len,
+                 MetadataPayload* const payload) {
+  if (metadata == NULL || metadata_len == 0 || payload == NULL) return 0;
+  payload->bytes = (uint8_t*)malloc(metadata_len);
+  if (payload->bytes == NULL) return 0;
+  payload->size = metadata_len;
+  memcpy(payload->bytes, metadata, metadata_len);
+  return 1;
+}
+
+// -----------------------------------------------------------------------------
--- a/external/libwebp/libwebp/imageio/metadata.h
+++ b/external/libwebp/libwebp/imageio/metadata.h
@@ -0,0 +1,47 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Metadata types and functions.
+//
+
+#ifndef WEBP_IMAGEIO_METADATA_H_
+#define WEBP_IMAGEIO_METADATA_H_
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct MetadataPayload {
+  uint8_t* bytes;
+  size_t size;
+} MetadataPayload;
+
+typedef struct Metadata {
+  MetadataPayload exif;
+  MetadataPayload iccp;
+  MetadataPayload xmp;
+} Metadata;
+
+#define METADATA_OFFSET(x) offsetof(Metadata, x)
+
+void MetadataInit(Metadata* const metadata);
+void MetadataPayloadDelete(MetadataPayload* const payload);
+void MetadataFree(Metadata* const metadata);
+
+// Stores 'metadata' to 'payload->bytes', returns false on allocation error.
+int MetadataCopy(const char* metadata, size_t metadata_len,
+                 MetadataPayload* const payload);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_METADATA_H_
--- a/external/libwebp/libwebp/imageio/pngdec.c
+++ b/external/libwebp/libwebp/imageio/pngdec.c
@@ -0,0 +1,374 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// PNG decode.
+
+#include "./pngdec.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include <stdio.h>
+
+#ifdef WEBP_HAVE_PNG
+#ifndef PNG_USER_MEM_SUPPORTED
+#define PNG_USER_MEM_SUPPORTED  // for png_create_read_struct_2
+#endif
+#include <png.h>
+#include <setjmp.h>   // note: this must be included *after* png.h
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/encode.h"
+#include "./imageio_util.h"
+#include "./metadata.h"
+
+#define LOCAL_PNG_VERSION ((PNG_LIBPNG_VER_MAJOR << 8) | PNG_LIBPNG_VER_MINOR)
+#define LOCAL_PNG_PREREQ(maj, min) \
+   (LOCAL_PNG_VERSION >= (((maj) << 8) | (min)))
+
+static void PNGAPI error_function(png_structp png, png_const_charp error) {
+  if (error != NULL) fprintf(stderr, "libpng error: %s\n", error);
+  longjmp(png_jmpbuf(png), 1);
+}
+
+#if LOCAL_PNG_PREREQ(1,4)
+typedef png_alloc_size_t LocalPngAllocSize;
+#else
+typedef png_size_t LocalPngAllocSize;
+#endif
+
+static png_voidp MallocFunc(png_structp png_ptr, LocalPngAllocSize size) {
+  (void)png_ptr;
+  if (size != (size_t)size) return NULL;
+  if (!ImgIoUtilCheckSizeArgumentsOverflow(size, 1)) return NULL;
+  return (png_voidp)malloc((size_t)size);
+}
+
+static void FreeFunc(png_structp png_ptr, png_voidp ptr) {
+  (void)png_ptr;
+  free(ptr);
+}
+
+// Converts the NULL terminated 'hexstring' which contains 2-byte character
+// representations of hex values to raw data.
+// 'hexstring' may contain values consisting of [A-F][a-f][0-9] in pairs,
+// e.g., 7af2..., separated by any number of newlines.
+// 'expected_length' is the anticipated processed size.
+// On success the raw buffer is returned with its length equivalent to
+// 'expected_length'. NULL is returned if the processed length is less than
+// 'expected_length' or any character aside from those above is encountered.
+// The returned buffer must be freed by the caller.
+static uint8_t* HexStringToBytes(const char* hexstring,
+                                 size_t expected_length) {
+  const char* src = hexstring;
+  size_t actual_length = 0;
+  uint8_t* const raw_data = (uint8_t*)malloc(expected_length);
+  uint8_t* dst;
+
+  if (raw_data == NULL) return NULL;
+
+  for (dst = raw_data; actual_length < expected_length && *src != '\0'; ++src) {
+    char* end;
+    char val[3];
+    if (*src == '\n') continue;
+    val[0] = *src++;
+    val[1] = *src;
+    val[2] = '\0';
+    *dst++ = (uint8_t)strtol(val, &end, 16);
+    if (end != val + 2) break;
+    ++actual_length;
+  }
+
+  if (actual_length != expected_length) {
+    free(raw_data);
+    return NULL;
+  }
+  return raw_data;
+}
+
+static int ProcessRawProfile(const char* profile, size_t profile_len,
+                             MetadataPayload* const payload) {
+  const char* src = profile;
+  char* end;
+  int expected_length;
+
+  if (profile == NULL || profile_len == 0) return 0;
+
+  // ImageMagick formats 'raw profiles' as
+  // '\n<name>\n<length>(%8lu)\n<hex payload>\n'.
+  if (*src != '\n') {
+    fprintf(stderr, "Malformed raw profile, expected '\\n' got '\\x%.2X'\n",
+            *src);
+    return 0;
+  }
+  ++src;
+  // skip the profile name and extract the length.
+  while (*src != '\0' && *src++ != '\n') {}
+  expected_length = (int)strtol(src, &end, 10);
+  if (*end != '\n') {
+    fprintf(stderr, "Malformed raw profile, expected '\\n' got '\\x%.2X'\n",
+            *end);
+    return 0;
+  }
+  ++end;
+
+  // 'end' now points to the profile payload.
+  payload->bytes = HexStringToBytes(end, expected_length);
+  if (payload->bytes == NULL) return 0;
+  payload->size = expected_length;
+  return 1;
+}
+
+static const struct {
+  const char* name;
+  int (*process)(const char* profile, size_t profile_len,
+                 MetadataPayload* const payload);
+  size_t storage_offset;
+} kPNGMetadataMap[] = {
+  // https://exiftool.org/TagNames/PNG.html#TextualData
+  // See also: ExifTool on CPAN.
+  { "Raw profile type exif", ProcessRawProfile, METADATA_OFFSET(exif) },
+  { "Raw profile type xmp",  ProcessRawProfile, METADATA_OFFSET(xmp) },
+  // Exiftool puts exif data in APP1 chunk, too.
+  { "Raw profile type APP1", ProcessRawProfile, METADATA_OFFSET(exif) },
+  // XMP Specification Part 3, Section 3 #PNG
+  { "XML:com.adobe.xmp",     MetadataCopy,      METADATA_OFFSET(xmp) },
+  { NULL, NULL, 0 },
+};
+
+// Looks for metadata at both the beginning and end of the PNG file, giving
+// preference to the head.
+// Returns true on success. The caller must use MetadataFree() on 'metadata' in
+// all cases.
+static int ExtractMetadataFromPNG(png_structp png,
+                                  png_infop const head_info,
+                                  png_infop const end_info,
+                                  Metadata* const metadata) {
+  int p;
+
+  for (p = 0; p < 2; ++p)  {
+    png_infop const info = (p == 0) ? head_info : end_info;
+    png_textp text = NULL;
+    const png_uint_32 num = png_get_text(png, info, &text, NULL);
+    png_uint_32 i;
+    // Look for EXIF / XMP metadata.
+    for (i = 0; i < num; ++i, ++text) {
+      int j;
+      for (j = 0; kPNGMetadataMap[j].name != NULL; ++j) {
+        if (!strcmp(text->key, kPNGMetadataMap[j].name)) {
+          MetadataPayload* const payload =
+              (MetadataPayload*)((uint8_t*)metadata +
+                                 kPNGMetadataMap[j].storage_offset);
+          png_size_t text_length;
+          switch (text->compression) {
+#ifdef PNG_iTXt_SUPPORTED
+            case PNG_ITXT_COMPRESSION_NONE:
+            case PNG_ITXT_COMPRESSION_zTXt:
+              text_length = text->itxt_length;
+              break;
+#endif
+            case PNG_TEXT_COMPRESSION_NONE:
+            case PNG_TEXT_COMPRESSION_zTXt:
+            default:
+              text_length = text->text_length;
+              break;
+          }
+          if (payload->bytes != NULL) {
+            fprintf(stderr, "Ignoring additional '%s'\n", text->key);
+          } else if (!kPNGMetadataMap[j].process(text->text, text_length,
+                                                 payload)) {
+            fprintf(stderr, "Failed to process: '%s'\n", text->key);
+            return 0;
+          }
+          break;
+        }
+      }
+    }
+    // Look for an ICC profile.
+    {
+      png_charp name;
+      int comp_type;
+#if LOCAL_PNG_PREREQ(1,5)
+      png_bytep profile;
+#else
+      png_charp profile;
+#endif
+      png_uint_32 len;
+
+      if (png_get_iCCP(png, info,
+                       &name, &comp_type, &profile, &len) == PNG_INFO_iCCP) {
+        if (!MetadataCopy((const char*)profile, len, &metadata->iccp)) return 0;
+      }
+    }
+  }
+  return 1;
+}
+
+typedef struct {
+  const uint8_t* data;
+  size_t data_size;
+  png_size_t offset;
+} PNGReadContext;
+
+static void ReadFunc(png_structp png_ptr, png_bytep data, png_size_t length) {
+  PNGReadContext* const ctx = (PNGReadContext*)png_get_io_ptr(png_ptr);
+  if (ctx->data_size - ctx->offset < length) {
+    png_error(png_ptr, "ReadFunc: invalid read length (overflow)!");
+  }
+  memcpy(data, ctx->data + ctx->offset, length);
+  ctx->offset += length;
+}
+
+int ReadPNG(const uint8_t* const data, size_t data_size,
+            struct WebPPicture* const pic,
+            int keep_alpha, struct Metadata* const metadata) {
+  volatile png_structp png = NULL;
+  volatile png_infop info = NULL;
+  volatile png_infop end_info = NULL;
+  PNGReadContext context = { NULL, 0, 0 };
+  int color_type, bit_depth, interlaced;
+  int num_channels;
+  int num_passes;
+  int p;
+  volatile int ok = 0;
+  png_uint_32 width, height, y;
+  int64_t stride;
+  uint8_t* volatile rgb = NULL;
+
+  if (data == NULL || data_size == 0 || pic == NULL) return 0;
+
+  context.data = data;
+  context.data_size = data_size;
+
+  png = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL,
+                                 NULL, MallocFunc, FreeFunc);
+  if (png == NULL) goto End;
+
+  png_set_error_fn(png, 0, error_function, NULL);
+  if (setjmp(png_jmpbuf(png))) {
+ Error:
+    MetadataFree(metadata);
+    goto End;
+  }
+
+#if LOCAL_PNG_PREREQ(1,5) || \
+    (LOCAL_PNG_PREREQ(1,4) && PNG_LIBPNG_VER_RELEASE >= 1)
+  // If it looks like the bitstream is going to need more memory than libpng's
+  // internal limit (default: 8M), try to (reasonably) raise it.
+  if (data_size > png_get_chunk_malloc_max(png) && data_size < (1u << 24)) {
+    png_set_chunk_malloc_max(png, data_size);
+  }
+#endif
+
+  info = png_create_info_struct(png);
+  if (info == NULL) goto Error;
+  end_info = png_create_info_struct(png);
+  if (end_info == NULL) goto Error;
+
+  png_set_read_fn(png, &context, ReadFunc);
+  png_read_info(png, info);
+  if (!png_get_IHDR(png, info,
+                    &width, &height, &bit_depth, &color_type, &interlaced,
+                    NULL, NULL)) goto Error;
+
+  png_set_strip_16(png);
+  png_set_packing(png);
+  if (color_type == PNG_COLOR_TYPE_PALETTE) {
+    png_set_palette_to_rgb(png);
+  }
+  if (color_type == PNG_COLOR_TYPE_GRAY ||
+      color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
+    if (bit_depth < 8) {
+      png_set_expand_gray_1_2_4_to_8(png);
+    }
+    png_set_gray_to_rgb(png);
+  }
+  if (png_get_valid(png, info, PNG_INFO_tRNS)) {
+    png_set_tRNS_to_alpha(png);
+  }
+
+  // Apply gamma correction if needed.
+  {
+    double image_gamma = 1 / 2.2, screen_gamma = 2.2;
+    int srgb_intent;
+    if (png_get_sRGB(png, info, &srgb_intent) ||
+        png_get_gAMA(png, info, &image_gamma)) {
+      png_set_gamma(png, screen_gamma, image_gamma);
+    }
+  }
+
+  if (!keep_alpha) {
+    png_set_strip_alpha(png);
+  }
+
+  num_passes = png_set_interlace_handling(png);
+  png_read_update_info(png, info);
+
+  num_channels = png_get_channels(png, info);
+  if (num_channels != 3 && num_channels != 4) {
+    goto Error;
+  }
+  stride = (int64_t)num_channels * width * sizeof(*rgb);
+  if (stride != (int)stride ||
+      !ImgIoUtilCheckSizeArgumentsOverflow(stride, height)) {
+    goto Error;
+  }
+
+  rgb = (uint8_t*)malloc((size_t)stride * height);
+  if (rgb == NULL) goto Error;
+  for (p = 0; p < num_passes; ++p) {
+    png_bytep row = rgb;
+    for (y = 0; y < height; ++y) {
+      png_read_rows(png, &row, NULL, 1);
+      row += stride;
+    }
+  }
+  png_read_end(png, end_info);
+
+  if (metadata != NULL &&
+      !ExtractMetadataFromPNG(png, info, end_info, metadata)) {
+    fprintf(stderr, "Error extracting PNG metadata!\n");
+    goto Error;
+  }
+
+  pic->width = (int)width;
+  pic->height = (int)height;
+  ok = (num_channels == 4) ? WebPPictureImportRGBA(pic, rgb, (int)stride)
+                           : WebPPictureImportRGB(pic, rgb, (int)stride);
+
+  if (!ok) {
+    goto Error;
+  }
+
+ End:
+  if (png != NULL) {
+    png_destroy_read_struct((png_structpp)&png,
+                            (png_infopp)&info, (png_infopp)&end_info);
+  }
+  free(rgb);
+  return ok;
+}
+#else  // !WEBP_HAVE_PNG
+int ReadPNG(const uint8_t* const data, size_t data_size,
+            struct WebPPicture* const pic,
+            int keep_alpha, struct Metadata* const metadata) {
+  (void)data;
+  (void)data_size;
+  (void)pic;
+  (void)keep_alpha;
+  (void)metadata;
+  fprintf(stderr, "PNG support not compiled. Please install the libpng "
+          "development package before building.\n");
+  return 0;
+}
+#endif  // WEBP_HAVE_PNG
+
+// -----------------------------------------------------------------------------
--- a/external/libwebp/libwebp/imageio/pngdec.h
+++ b/external/libwebp/libwebp/imageio/pngdec.h
@@ -0,0 +1,37 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// PNG decode.
+
+#ifndef WEBP_IMAGEIO_PNGDEC_H_
+#define WEBP_IMAGEIO_PNGDEC_H_
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+// Reads a PNG from 'data', returning the decoded output in 'pic'.
+// Output is RGBA or YUVA, depending on pic->use_argb value.
+// If 'keep_alpha' is true and the PNG has an alpha channel, the output is RGBA
+// or YUVA. Otherwise, alpha channel is dropped and output is RGB or YUV.
+// Returns true on success.
+int ReadPNG(const uint8_t* const data, size_t data_size,
+            struct WebPPicture* const pic,
+            int keep_alpha, struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_PNGDEC_H_
--- a/external/libwebp/libwebp/imageio/pnmdec.c
+++ b/external/libwebp/libwebp/imageio/pnmdec.c
@@ -0,0 +1,301 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// (limited) PNM decoder
+
+#include "./pnmdec.h"
+
+#include <assert.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "webp/encode.h"
+#include "./imageio_util.h"
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#define snprintf _snprintf
+#endif
+
+typedef enum {
+  WIDTH_FLAG      = 1 << 0,
+  HEIGHT_FLAG     = 1 << 1,
+  DEPTH_FLAG      = 1 << 2,
+  MAXVAL_FLAG     = 1 << 3,
+  TUPLE_FLAG      = 1 << 4,
+  ALL_NEEDED_FLAGS = WIDTH_FLAG | HEIGHT_FLAG | DEPTH_FLAG | MAXVAL_FLAG
+} PNMFlags;
+
+typedef struct {
+  const uint8_t* data;
+  size_t data_size;
+  int width, height;
+  int bytes_per_px;
+  int depth;          // 1 (grayscale), 2 (grayscale + alpha), 3 (rgb), 4 (rgba)
+  int max_value;
+  int type;           // 5, 6 or 7
+  int seen_flags;
+} PNMInfo;
+
+// -----------------------------------------------------------------------------
+// PNM decoding
+
+#define MAX_LINE_SIZE 1024
+static const size_t kMinPNMHeaderSize = 3;
+
+static size_t ReadLine(const uint8_t* const data, size_t off, size_t data_size,
+                       char out[MAX_LINE_SIZE + 1], size_t* const out_size) {
+  size_t i = 0;
+  *out_size = 0;
+ redo:
+  for (i = 0; i < MAX_LINE_SIZE && off < data_size; ++i) {
+    out[i] = data[off++];
+    if (out[i] == '\n') break;
+  }
+  if (off < data_size) {
+    if (i == 0) goto redo;         // empty line
+    if (out[0] == '#') goto redo;  // skip comment
+  }
+  out[i] = 0;   // safety sentinel
+  *out_size = i;
+  return off;
+}
+
+static size_t FlagError(const char flag[]) {
+  fprintf(stderr, "PAM header error: flags '%s' already seen.\n", flag);
+  return 0;
+}
+
+// inspired from http://netpbm.sourceforge.net/doc/pam.html
+static size_t ReadPAMFields(PNMInfo* const info, size_t off) {
+  char out[MAX_LINE_SIZE + 1];
+  size_t out_size;
+  int tmp;
+  int expected_depth = -1;
+  assert(info != NULL);
+  while (1) {
+    off = ReadLine(info->data, off, info->data_size, out, &out_size);
+    if (off == 0) return 0;
+    if (sscanf(out, "WIDTH %d", &tmp) == 1) {
+      if (info->seen_flags & WIDTH_FLAG) return FlagError("WIDTH");
+      info->seen_flags |= WIDTH_FLAG;
+      info->width = tmp;
+    } else if (sscanf(out, "HEIGHT %d", &tmp) == 1) {
+      if (info->seen_flags & HEIGHT_FLAG) return FlagError("HEIGHT");
+      info->seen_flags |= HEIGHT_FLAG;
+      info->height = tmp;
+    } else if (sscanf(out, "DEPTH %d", &tmp) == 1) {
+      if (info->seen_flags & DEPTH_FLAG) return FlagError("DEPTH");
+      info->seen_flags |= DEPTH_FLAG;
+      info->depth = tmp;
+    } else if (sscanf(out, "MAXVAL %d", &tmp) == 1) {
+      if (info->seen_flags & MAXVAL_FLAG) return FlagError("MAXVAL");
+      info->seen_flags |= MAXVAL_FLAG;
+      info->max_value = tmp;
+    } else if (!strcmp(out, "TUPLTYPE RGB_ALPHA")) {
+      expected_depth = 4;
+      info->seen_flags |= TUPLE_FLAG;
+    } else if (!strcmp(out, "TUPLTYPE RGB")) {
+      expected_depth = 3;
+      info->seen_flags |= TUPLE_FLAG;
+    } else if (!strcmp(out, "TUPLTYPE GRAYSCALE_ALPHA")) {
+      expected_depth = 2;
+      info->seen_flags |= TUPLE_FLAG;
+    } else if (!strcmp(out, "TUPLTYPE GRAYSCALE")) {
+      expected_depth = 1;
+      info->seen_flags |= TUPLE_FLAG;
+    } else if (!strcmp(out, "ENDHDR")) {
+      break;
+    } else {
+      static const char kEllipsis[] = " ...";
+      const size_t kLen = strlen(kEllipsis) + 1;  // +1 = trailing \0
+      int i;
+      if (out_size > 20) snprintf(out + 20 - kLen, kLen, kEllipsis);
+      for (i = 0; i < (int)strlen(out); ++i) {
+        // isprint() might trigger a "char-subscripts" warning if given a char.
+        if (!isprint((int)out[i])) out[i] = ' ';
+      }
+      fprintf(stderr, "PAM header error: unrecognized entry [%s]\n", out);
+      return 0;
+    }
+  }
+  if (!(info->seen_flags & ALL_NEEDED_FLAGS)) {
+    fprintf(stderr, "PAM header error: missing tags%s%s%s%s\n",
+            (info->seen_flags & WIDTH_FLAG) ? "" : " WIDTH",
+            (info->seen_flags & HEIGHT_FLAG) ? "" : " HEIGHT",
+            (info->seen_flags & DEPTH_FLAG) ? "" : " DEPTH",
+            (info->seen_flags & MAXVAL_FLAG) ? "" : " MAXVAL");
+    return 0;
+  }
+  if (expected_depth != -1 && info->depth != expected_depth) {
+    fprintf(stderr, "PAM header error: expected DEPTH %d but got DEPTH %d\n",
+            expected_depth, info->depth);
+    return 0;
+  }
+  return off;
+}
+
+static size_t ReadHeader(PNMInfo* const info) {
+  size_t off = 0;
+  char out[MAX_LINE_SIZE + 1];
+  size_t out_size;
+  if (info == NULL) return 0;
+  if (info->data == NULL || info->data_size < kMinPNMHeaderSize) return 0;
+
+  info->width = info->height = 0;
+  info->type = -1;
+  info->seen_flags = 0;
+  info->bytes_per_px = 0;
+  info->depth = 0;
+  info->max_value = 0;
+
+  off = ReadLine(info->data, off, info->data_size, out, &out_size);
+  if (off == 0 || sscanf(out, "P%d", &info->type) != 1) return 0;
+  if (info->type == 7) {
+    off = ReadPAMFields(info, off);
+  } else {
+    off = ReadLine(info->data, off, info->data_size, out, &out_size);
+    if (off == 0 || sscanf(out, "%d %d", &info->width, &info->height) != 2) {
+      return 0;
+    }
+    off = ReadLine(info->data, off, info->data_size, out, &out_size);
+    if (off == 0 || sscanf(out, "%d", &info->max_value) != 1) return 0;
+
+    // finish initializing missing fields
+    info->depth = (info->type == 5) ? 1 : 3;
+  }
+  // perform some basic numerical validation
+  if (info->width <= 0 || info->height <= 0 ||
+      info->type <= 0 || info->type >= 9 ||
+      info->depth <= 0 || info->depth > 4 ||
+      info->max_value <= 0 || info->max_value >= 65536) {
+    return 0;
+  }
+  info->bytes_per_px = info->depth * (info->max_value > 255 ? 2 : 1);
+  return off;
+}
+
+int ReadPNM(const uint8_t* const data, size_t data_size,
+            WebPPicture* const pic, int keep_alpha,
+            struct Metadata* const metadata) {
+  int ok = 0;
+  int i, j;
+  uint64_t stride, pixel_bytes, sample_size, depth;
+  uint8_t* rgb = NULL, *tmp_rgb;
+  size_t offset;
+  PNMInfo info;
+
+  info.data = data;
+  info.data_size = data_size;
+  offset = ReadHeader(&info);
+  if (offset == 0) {
+    fprintf(stderr, "Error parsing PNM header.\n");
+    goto End;
+  }
+
+  if (info.type < 5 || info.type > 7) {
+    fprintf(stderr, "Unsupported P%d PNM format.\n", info.type);
+    goto End;
+  }
+
+  // Some basic validations.
+  if (pic == NULL) goto End;
+  if (info.width > WEBP_MAX_DIMENSION || info.height > WEBP_MAX_DIMENSION) {
+    fprintf(stderr, "Invalid %dx%d dimension for PNM\n",
+                    info.width, info.height);
+    goto End;
+  }
+
+  pixel_bytes = (uint64_t)info.width * info.height * info.bytes_per_px;
+  if (data_size < offset + pixel_bytes) {
+    fprintf(stderr, "Truncated PNM file (P%d).\n", info.type);
+    goto End;
+  }
+  sample_size = (info.max_value > 255) ? 2 : 1;
+  // final depth
+  depth = (info.depth == 1 || info.depth == 3 || !keep_alpha) ? 3 : 4;
+  stride = depth * info.width;
+  if (stride != (size_t)stride ||
+      !ImgIoUtilCheckSizeArgumentsOverflow(stride, info.height)) {
+    goto End;
+  }
+
+  rgb = (uint8_t*)malloc((size_t)stride * info.height);
+  if (rgb == NULL) goto End;
+
+  // Convert input.
+  // We only optimize for the sample_size=1, max_value=255, depth=1 case.
+  tmp_rgb = rgb;
+  for (j = 0; j < info.height; ++j) {
+    const uint8_t* in = data + offset;
+    offset += info.bytes_per_px * info.width;
+    assert(offset <= data_size);
+    if (info.max_value == 255 && info.depth >= 3) {
+      // RGB or RGBA
+      if (info.depth == 3 || keep_alpha) {
+        memcpy(tmp_rgb, in, info.depth * info.width * sizeof(*in));
+      } else {
+        assert(info.depth == 4 && !keep_alpha);
+        for (i = 0; i < info.width; ++i) {
+          tmp_rgb[3 * i + 0] = in[4 * i + 0];
+          tmp_rgb[3 * i + 1] = in[4 * i + 1];
+          tmp_rgb[3 * i + 2] = in[4 * i + 2];
+        }
+      }
+    } else {
+      // Unoptimized case, we need to handle non-trivial operations:
+      //   * convert 16b to 8b (if max_value > 255)
+      //   * rescale to [0..255] range (if max_value != 255)
+      //   * drop the alpha channel (if keep_alpha is false)
+      const uint32_t round = info.max_value / 2;
+      int k = 0;
+      for (i = 0; i < info.width * info.depth; ++i) {
+        uint32_t v = (sample_size == 2) ? 256u * in[2 * i + 0] + in[2 * i + 1]
+                   : in[i];
+        if (info.max_value != 255) v = (v * 255u + round) / info.max_value;
+        if (v > 255u) v = 255u;
+        if (info.depth > 2) {
+          if (!keep_alpha && info.depth == 4 && (i % 4) == 3) {
+            // skip alpha
+          } else {
+            tmp_rgb[k] = v;
+            k += 1;
+          }
+        } else if (info.depth == 1 || (i % 2) == 0) {
+          tmp_rgb[k + 0] = tmp_rgb[k + 1] = tmp_rgb[k + 2] = v;
+          k += 3;
+        } else if (keep_alpha && info.depth == 2) {
+          tmp_rgb[k] = v;
+          k += 1;
+        } else {
+          // skip alpha
+        }
+      }
+    }
+    tmp_rgb += stride;
+  }
+
+  // WebP conversion.
+  pic->width = info.width;
+  pic->height = info.height;
+  ok = (depth == 4) ? WebPPictureImportRGBA(pic, rgb, (int)stride)
+                    : WebPPictureImportRGB(pic, rgb, (int)stride);
+  if (!ok) goto End;
+
+  ok = 1;
+ End:
+  free((void*)rgb);
+
+  (void)metadata;
+  (void)keep_alpha;
+  return ok;
+}
+
+// -----------------------------------------------------------------------------
--- a/external/libwebp/libwebp/imageio/pnmdec.h
+++ b/external/libwebp/libwebp/imageio/pnmdec.h
@@ -0,0 +1,37 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// partial PNM format decoder (ppm/pgm)
+
+#ifndef WEBP_IMAGEIO_PNMDEC_H_
+#define WEBP_IMAGEIO_PNMDEC_H_
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+// Reads a PNM file from 'data', returning the decoded output in 'pic'.
+// The output is RGB or YUV depending on pic->use_argb value.
+// Returns true on success.
+// 'metadata' has no effect, but is kept for coherence with other signatures
+// for image readers.
+int ReadPNM(const uint8_t* const data, size_t data_size,
+            struct WebPPicture* const pic, int keep_alpha,
+            struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_PNMDEC_H_
--- a/external/libwebp/libwebp/imageio/tiffdec.c
+++ b/external/libwebp/libwebp/imageio/tiffdec.c
@@ -0,0 +1,293 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// TIFF decode.
+
+#include "./tiffdec.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+
+#ifdef WEBP_HAVE_TIFF
+#include <tiffio.h>
+
+#include "webp/encode.h"
+#include "./imageio_util.h"
+#include "./metadata.h"
+
+static const struct {
+  ttag_t tag;
+  size_t storage_offset;
+} kTIFFMetadataMap[] = {
+  { TIFFTAG_ICCPROFILE, METADATA_OFFSET(iccp) },
+  { TIFFTAG_XMLPACKET,  METADATA_OFFSET(xmp) },
+  { 0, 0 },
+};
+
+// Returns true on success. The caller must use MetadataFree() on 'metadata' in
+// all cases.
+static int ExtractMetadataFromTIFF(TIFF* const tif, Metadata* const metadata) {
+  int i;
+  toff_t exif_ifd_offset;
+
+  for (i = 0; kTIFFMetadataMap[i].tag != 0; ++i) {
+    MetadataPayload* const payload =
+        (MetadataPayload*)((uint8_t*)metadata +
+                           kTIFFMetadataMap[i].storage_offset);
+    void* tag_data;
+    uint32_t tag_data_len;
+
+    if (TIFFGetField(tif, kTIFFMetadataMap[i].tag, &tag_data_len, &tag_data) &&
+        !MetadataCopy((const char*)tag_data, tag_data_len, payload)) {
+      return 0;
+    }
+  }
+
+  // TODO(jzern): To extract the raw EXIF directory some parsing of it would be
+  // necessary to determine the overall size. In addition, value offsets in
+  // individual directory entries may need to be updated as, depending on the
+  // type, they are file based.
+  // Exif 2.2 Section 4.6.2 Tag Structure
+  // TIFF Revision 6.0 Part 1 Section 2 TIFF Structure #Image File Directory
+  if (TIFFGetField(tif, TIFFTAG_EXIFIFD, &exif_ifd_offset)) {
+    fprintf(stderr, "Warning: EXIF extraction from TIFF is unsupported.\n");
+  }
+  return 1;
+}
+
+// Ad-hoc structure to supply read-from-memory functionalities.
+typedef struct {
+  const uint8_t* data;
+  toff_t size;
+  toff_t pos;
+} MyData;
+
+static int MyClose(thandle_t opaque) {
+  (void)opaque;
+  return 0;
+}
+
+static toff_t MySize(thandle_t opaque) {
+  const MyData* const my_data = (MyData*)opaque;
+  return my_data->size;
+}
+
+static toff_t MySeek(thandle_t opaque, toff_t offset, int whence) {
+  MyData* const my_data = (MyData*)opaque;
+  offset += (whence == SEEK_CUR) ? my_data->pos
+          : (whence == SEEK_SET) ? 0
+          : my_data->size;
+  if (offset > my_data->size) return (toff_t)-1;
+  my_data->pos = offset;
+  return offset;
+}
+
+static int MyMapFile(thandle_t opaque, void** base, toff_t* size) {
+  (void)opaque;
+  (void)base;
+  (void)size;
+  return 0;
+}
+static void MyUnmapFile(thandle_t opaque, void* base, toff_t size) {
+  (void)opaque;
+  (void)base;
+  (void)size;
+}
+
+static tsize_t MyRead(thandle_t opaque, void* dst, tsize_t size) {
+  MyData* const my_data = (MyData*)opaque;
+  if (my_data->pos + size > my_data->size) {
+    size = (tsize_t)(my_data->size - my_data->pos);
+  }
+  if (size > 0) {
+    memcpy(dst, my_data->data + my_data->pos, size);
+    my_data->pos += size;
+  }
+  return size;
+}
+
+// Unmultiply Argb data. Taken from dsp/alpha_processing
+// (we don't want to force a dependency to a libdspdec library).
+#define MFIX 24    // 24bit fixed-point arithmetic
+#define HALF ((1u << MFIX) >> 1)
+
+static uint32_t Unmult(uint8_t x, uint32_t mult) {
+  const uint32_t v = (x * mult + HALF) >> MFIX;
+  return (v > 255u) ? 255u : v;
+}
+
+static WEBP_INLINE uint32_t GetScale(uint32_t a) {
+  return (255u << MFIX) / a;
+}
+
+#undef MFIX
+#undef HALF
+
+static void MultARGBRow(uint8_t* ptr, int width) {
+  int x;
+  for (x = 0; x < width; ++x, ptr += 4) {
+    const uint32_t alpha = ptr[3];
+    if (alpha < 255) {
+      if (alpha == 0) {   // alpha == 0
+        ptr[0] = ptr[1] = ptr[2] = 0;
+      } else {
+        const uint32_t scale = GetScale(alpha);
+        ptr[0] = Unmult(ptr[0], scale);
+        ptr[1] = Unmult(ptr[1], scale);
+        ptr[2] = Unmult(ptr[2], scale);
+      }
+    }
+  }
+}
+
+int ReadTIFF(const uint8_t* const data, size_t data_size,
+             WebPPicture* const pic, int keep_alpha,
+             Metadata* const metadata) {
+  MyData my_data = { data, (toff_t)data_size, 0 };
+  TIFF* tif;
+  uint32_t image_width, image_height, tile_width, tile_height;
+  uint64_t stride;
+  uint16_t samples_per_px = 0;
+  uint16_t extra_samples = 0;
+  uint16_t* extra_samples_ptr = NULL;
+  uint32_t* raster;
+  int64_t alloc_size;
+  int ok = 0;
+  tdir_t dircount;
+
+  if (data == NULL || data_size == 0 || data_size > INT_MAX || pic == NULL) {
+    return 0;
+  }
+
+  tif = TIFFClientOpen("Memory", "r", &my_data,
+                       MyRead, MyRead, MySeek, MyClose,
+                       MySize, MyMapFile, MyUnmapFile);
+  if (tif == NULL) {
+    fprintf(stderr, "Error! Cannot parse TIFF file\n");
+    return 0;
+  }
+
+  dircount = TIFFNumberOfDirectories(tif);
+  if (dircount > 1) {
+    fprintf(stderr, "Warning: multi-directory TIFF files are not supported.\n"
+                    "Only the first will be used, %d will be ignored.\n",
+                    dircount - 1);
+  }
+  if (!TIFFGetFieldDefaulted(tif, TIFFTAG_SAMPLESPERPIXEL, &samples_per_px)) {
+    fprintf(stderr, "Error! Cannot retrieve TIFF samples-per-pixel info.\n");
+    goto End;
+  }
+  if (!(samples_per_px == 1 || samples_per_px == 3 || samples_per_px == 4)) {
+    goto End;  // not supported
+  }
+
+  if (!(TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &image_width) &&
+        TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &image_height))) {
+    fprintf(stderr, "Error! Cannot retrieve TIFF image dimensions.\n");
+    goto End;
+  }
+  stride = (uint64_t)image_width * sizeof(*raster);
+  if (!ImgIoUtilCheckSizeArgumentsOverflow(stride, image_height)) {
+    fprintf(stderr, "Error! TIFF image dimension (%d x %d) is too large.\n",
+            image_width, image_height);
+    goto End;
+  }
+
+  // According to spec, a tile can be bigger than the image. However it should
+  // be a multiple of 16 and not way too large, so check that it's not more
+  // than twice the image size, for dimensions above some arbitrary minimum
+  // 32. We also check that they respect WebP's dimension and memory limit.
+  // Note that a tile can be 6byte/px in some cases. Here we assume
+  // 4byte/px with sizeof(*raster), to be conservative.
+  if (TIFFGetField(tif, TIFFTAG_TILEWIDTH, &tile_width) &&
+      TIFFGetField(tif, TIFFTAG_TILELENGTH, &tile_height)) {
+    if ((tile_width > 32 && tile_width / 2 > image_width) ||
+        (tile_height > 32 && tile_height / 2 > image_height) ||
+        !ImgIoUtilCheckSizeArgumentsOverflow(
+            (uint64_t)tile_width * sizeof(*raster), tile_height)) {
+      fprintf(stderr, "Error! TIFF tile dimension (%d x %d) is too large.\n",
+              tile_width, tile_height);
+      goto End;
+    }
+  }
+
+  if (samples_per_px > 3 && !TIFFGetField(tif, TIFFTAG_EXTRASAMPLES,
+                                          &extra_samples, &extra_samples_ptr)) {
+    fprintf(stderr, "Error! Cannot retrieve TIFF ExtraSamples info.\n");
+    goto End;
+  }
+
+  // _Tiffmalloc uses a signed type for size.
+  alloc_size = (int64_t)(stride * image_height);
+  if (alloc_size < 0 || alloc_size != (tsize_t)alloc_size) goto End;
+
+  raster = (uint32_t*)_TIFFmalloc((tsize_t)alloc_size);
+  if (raster != NULL) {
+    if (TIFFReadRGBAImageOriented(tif, image_width, image_height, raster,
+                                  ORIENTATION_TOPLEFT, 1)) {
+      pic->width = image_width;
+      pic->height = image_height;
+      // TIFF data is ABGR
+#ifdef WORDS_BIGENDIAN
+      TIFFSwabArrayOfLong(raster, image_width * image_height);
+#endif
+      // if we have an alpha channel, we must un-multiply from rgbA to RGBA
+      if (extra_samples == 1 && extra_samples_ptr != NULL &&
+          extra_samples_ptr[0] == EXTRASAMPLE_ASSOCALPHA) {
+        uint32_t y;
+        uint8_t* tmp = (uint8_t*)raster;
+        for (y = 0; y < image_height; ++y) {
+          MultARGBRow(tmp, image_width);
+          tmp += stride;
+        }
+      }
+      ok = keep_alpha
+         ? WebPPictureImportRGBA(pic, (const uint8_t*)raster, (int)stride)
+         : WebPPictureImportRGBX(pic, (const uint8_t*)raster, (int)stride);
+    }
+    _TIFFfree(raster);
+  } else {
+    fprintf(stderr, "Error allocating TIFF RGBA memory!\n");
+  }
+
+  if (ok) {
+    if (metadata != NULL) {
+      ok = ExtractMetadataFromTIFF(tif, metadata);
+      if (!ok) {
+        fprintf(stderr, "Error extracting TIFF metadata!\n");
+        MetadataFree(metadata);
+        WebPPictureFree(pic);
+      }
+    }
+  }
+ End:
+  TIFFClose(tif);
+  return ok;
+}
+#else  // !WEBP_HAVE_TIFF
+int ReadTIFF(const uint8_t* const data, size_t data_size,
+             struct WebPPicture* const pic, int keep_alpha,
+             struct Metadata* const metadata) {
+  (void)data;
+  (void)data_size;
+  (void)pic;
+  (void)keep_alpha;
+  (void)metadata;
+  fprintf(stderr, "TIFF support not compiled. Please install the libtiff "
+          "development package before building.\n");
+  return 0;
+}
+#endif  // WEBP_HAVE_TIFF
+
+// -----------------------------------------------------------------------------
--- a/external/libwebp/libwebp/imageio/tiffdec.h
+++ b/external/libwebp/libwebp/imageio/tiffdec.h
@@ -0,0 +1,37 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// TIFF decode.
+
+#ifndef WEBP_IMAGEIO_TIFFDEC_H_
+#define WEBP_IMAGEIO_TIFFDEC_H_
+
+#include "webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+// Reads a TIFF from 'data', returning the decoded output in 'pic'.
+// Output is RGBA or YUVA, depending on pic->use_argb value.
+// If 'keep_alpha' is true and the TIFF has an alpha channel, the output is RGBA
+// or YUVA. Otherwise, alpha channel is dropped and output is RGB or YUV.
+// Returns true on success.
+int ReadTIFF(const uint8_t* const data, size_t data_size,
+             struct WebPPicture* const pic, int keep_alpha,
+             struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_TIFFDEC_H_
--- a/external/libwebp/libwebp/imageio/webpdec.c
+++ b/external/libwebp/libwebp/imageio/webpdec.c
@@ -0,0 +1,244 @@
+// Copyright 2014 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// WebP decode.
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "./webpdec.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "webp/decode.h"
+#include "webp/demux.h"
+#include "webp/encode.h"
+#include "../examples/unicode.h"
+#include "./imageio_util.h"
+#include "./metadata.h"
+
+//------------------------------------------------------------------------------
+// WebP decoding
+
+static const char* const kStatusMessages[VP8_STATUS_NOT_ENOUGH_DATA + 1] = {
+  "OK", "OUT_OF_MEMORY", "INVALID_PARAM", "BITSTREAM_ERROR",
+  "UNSUPPORTED_FEATURE", "SUSPENDED", "USER_ABORT", "NOT_ENOUGH_DATA"
+};
+
+static void PrintAnimationWarning(const WebPDecoderConfig* const config) {
+  if (config->input.has_animation) {
+    fprintf(stderr,
+            "Error! Decoding of an animated WebP file is not supported.\n"
+            "       Use webpmux to extract the individual frames or\n"
+            "       vwebp to view this image.\n");
+  }
+}
+
+void PrintWebPError(const char* const in_file, int status) {
+  WFPRINTF(stderr, "Decoding of %s failed.\n", (const W_CHAR*)in_file);
+  fprintf(stderr, "Status: %d", status);
+  if (status >= VP8_STATUS_OK && status <= VP8_STATUS_NOT_ENOUGH_DATA) {
+    fprintf(stderr, "(%s)", kStatusMessages[status]);
+  }
+  fprintf(stderr, "\n");
+}
+
+int LoadWebP(const char* const in_file,
+             const uint8_t** data, size_t* data_size,
+             WebPBitstreamFeatures* bitstream) {
+  VP8StatusCode status;
+  WebPBitstreamFeatures local_features;
+  if (!ImgIoUtilReadFile(in_file, data, data_size)) return 0;
+
+  if (bitstream == NULL) {
+    bitstream = &local_features;
+  }
+
+  status = WebPGetFeatures(*data, *data_size, bitstream);
+  if (status != VP8_STATUS_OK) {
+    WebPFree((void*)*data);
+    *data = NULL;
+    *data_size = 0;
+    PrintWebPError(in_file, status);
+    return 0;
+  }
+  return 1;
+}
+
+//------------------------------------------------------------------------------
+
+VP8StatusCode DecodeWebP(const uint8_t* const data, size_t data_size,
+                         WebPDecoderConfig* const config) {
+  if (config == NULL) return VP8_STATUS_INVALID_PARAM;
+  PrintAnimationWarning(config);
+  return WebPDecode(data, data_size, config);
+}
+
+VP8StatusCode DecodeWebPIncremental(
+    const uint8_t* const data, size_t data_size,
+    WebPDecoderConfig* const config) {
+  VP8StatusCode status = VP8_STATUS_OK;
+  if (config == NULL) return VP8_STATUS_INVALID_PARAM;
+
+  PrintAnimationWarning(config);
+
+  // Decoding call.
+  {
+    WebPIDecoder* const idec = WebPIDecode(data, data_size, config);
+    if (idec == NULL) {
+      fprintf(stderr, "Failed during WebPIDecode().\n");
+      return VP8_STATUS_OUT_OF_MEMORY;
+    } else {
+      status = WebPIUpdate(idec, data, data_size);
+      WebPIDelete(idec);
+    }
+  }
+  return status;
+}
+
+// -----------------------------------------------------------------------------
+// Metadata
+
+static int ExtractMetadata(const uint8_t* const data, size_t data_size,
+                           Metadata* const metadata) {
+  WebPData webp_data = { data, data_size };
+  WebPDemuxer* const demux = WebPDemux(&webp_data);
+  WebPChunkIterator chunk_iter;
+  uint32_t flags;
+
+  if (demux == NULL) return 0;
+  assert(metadata != NULL);
+
+  flags = WebPDemuxGetI(demux, WEBP_FF_FORMAT_FLAGS);
+
+  if ((flags & ICCP_FLAG) && WebPDemuxGetChunk(demux, "ICCP", 1, &chunk_iter)) {
+    MetadataCopy((const char*)chunk_iter.chunk.bytes, chunk_iter.chunk.size,
+                 &metadata->iccp);
+    WebPDemuxReleaseChunkIterator(&chunk_iter);
+  }
+  if ((flags & EXIF_FLAG) && WebPDemuxGetChunk(demux, "EXIF", 1, &chunk_iter)) {
+    MetadataCopy((const char*)chunk_iter.chunk.bytes, chunk_iter.chunk.size,
+                 &metadata->exif);
+    WebPDemuxReleaseChunkIterator(&chunk_iter);
+  }
+  if ((flags & XMP_FLAG) && WebPDemuxGetChunk(demux, "XMP ", 1, &chunk_iter)) {
+    MetadataCopy((const char*)chunk_iter.chunk.bytes, chunk_iter.chunk.size,
+                 &metadata->xmp);
+    WebPDemuxReleaseChunkIterator(&chunk_iter);
+  }
+  WebPDemuxDelete(demux);
+  return 1;
+}
+
+// -----------------------------------------------------------------------------
+
+int ReadWebP(const uint8_t* const data, size_t data_size,
+             WebPPicture* const pic,
+             int keep_alpha, Metadata* const metadata) {
+  int ok = 0;
+  VP8StatusCode status = VP8_STATUS_OK;
+  WebPDecoderConfig config;
+  WebPDecBuffer* const output_buffer = &config.output;
+  WebPBitstreamFeatures* const bitstream = &config.input;
+
+  if (data == NULL || data_size == 0 || pic == NULL) return 0;
+
+  if (!WebPInitDecoderConfig(&config)) {
+    fprintf(stderr, "Library version mismatch!\n");
+    return 0;
+  }
+
+  status = WebPGetFeatures(data, data_size, bitstream);
+  if (status != VP8_STATUS_OK) {
+    PrintWebPError("input data", status);
+    return 0;
+  }
+
+  do {
+    const int has_alpha = keep_alpha && bitstream->has_alpha;
+    uint64_t stride;
+    pic->width = bitstream->width;
+    pic->height = bitstream->height;
+    if (pic->use_argb) {
+      stride = (uint64_t)bitstream->width * 4;
+    } else {
+      stride = (uint64_t)bitstream->width * (has_alpha ? 5 : 3) / 2;
+      pic->colorspace = has_alpha ? WEBP_YUV420A : WEBP_YUV420;
+    }
+
+    if (!ImgIoUtilCheckSizeArgumentsOverflow(stride, bitstream->height)) {
+      status = VP8_STATUS_OUT_OF_MEMORY;
+      break;
+    }
+
+    ok = WebPPictureAlloc(pic);
+    if (!ok) {
+      status = VP8_STATUS_OUT_OF_MEMORY;
+      break;
+    }
+    if (pic->use_argb) {
+#ifdef WORDS_BIGENDIAN
+      output_buffer->colorspace = MODE_ARGB;
+#else
+      output_buffer->colorspace = MODE_BGRA;
+#endif
+      output_buffer->u.RGBA.rgba = (uint8_t*)pic->argb;
+      output_buffer->u.RGBA.stride = pic->argb_stride * sizeof(uint32_t);
+      output_buffer->u.RGBA.size = output_buffer->u.RGBA.stride * pic->height;
+    } else {
+      output_buffer->colorspace = has_alpha ? MODE_YUVA : MODE_YUV;
+      output_buffer->u.YUVA.y = pic->y;
+      output_buffer->u.YUVA.u = pic->u;
+      output_buffer->u.YUVA.v = pic->v;
+      output_buffer->u.YUVA.a = has_alpha ? pic->a : NULL;
+      output_buffer->u.YUVA.y_stride = pic->y_stride;
+      output_buffer->u.YUVA.u_stride = pic->uv_stride;
+      output_buffer->u.YUVA.v_stride = pic->uv_stride;
+      output_buffer->u.YUVA.a_stride = has_alpha ? pic->a_stride : 0;
+      output_buffer->u.YUVA.y_size = pic->height * pic->y_stride;
+      output_buffer->u.YUVA.u_size = (pic->height + 1) / 2 * pic->uv_stride;
+      output_buffer->u.YUVA.v_size = (pic->height + 1) / 2 * pic->uv_stride;
+      output_buffer->u.YUVA.a_size = pic->height * pic->a_stride;
+    }
+    output_buffer->is_external_memory = 1;
+
+    status = DecodeWebP(data, data_size, &config);
+    ok = (status == VP8_STATUS_OK);
+    if (ok && !keep_alpha && pic->use_argb) {
+      // Need to wipe out the alpha value, as requested.
+      int x, y;
+      uint32_t* argb = pic->argb;
+      for (y = 0; y < pic->height; ++y) {
+        for (x = 0; x < pic->width; ++x) argb[x] |= 0xff000000u;
+        argb += pic->argb_stride;
+      }
+    }
+  } while (0);   // <- so we can 'break' out of the loop
+
+  if (status != VP8_STATUS_OK) {
+    PrintWebPError("input data", status);
+    ok = 0;
+  }
+
+  WebPFreeDecBuffer(output_buffer);
+
+  if (ok && metadata != NULL) {
+    ok = ExtractMetadata(data, data_size, metadata);
+    if (!ok) {
+      PrintWebPError("metadata", VP8_STATUS_BITSTREAM_ERROR);
+    }
+  }
+  if (!ok) WebPPictureFree(pic);
+  return ok;
+}
+
+// -----------------------------------------------------------------------------
--- a/external/libwebp/libwebp/imageio/webpdec.h
+++ b/external/libwebp/libwebp/imageio/webpdec.h
@@ -0,0 +1,67 @@
+// Copyright 2014 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// WebP decode.
+
+#ifndef WEBP_IMAGEIO_WEBPDEC_H_
+#define WEBP_IMAGEIO_WEBPDEC_H_
+
+#include "webp/decode.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+//------------------------------------------------------------------------------
+// WebP decoding
+
+// Prints an informative error message regarding decode failure of 'in_file'.
+// 'status' is treated as a VP8StatusCode and if valid will be printed as a
+// text string.
+void PrintWebPError(const char* const in_file, int status);
+
+// Reads a WebP from 'in_file', returning the contents and size in 'data' and
+// 'data_size'. If not NULL, 'bitstream' is populated using WebPGetFeatures().
+// Returns true on success.
+int LoadWebP(const char* const in_file,
+             const uint8_t** data, size_t* data_size,
+             WebPBitstreamFeatures* bitstream);
+
+// Decodes the WebP contained in 'data'.
+// 'config' is a structure previously initialized by WebPInitDecoderConfig().
+// 'config->output' should have the desired colorspace selected.
+// Returns the decoder status. On success 'config->output' will contain the
+// decoded picture.
+VP8StatusCode DecodeWebP(const uint8_t* const data, size_t data_size,
+                         WebPDecoderConfig* const config);
+
+// Same as DecodeWebP(), but using the incremental decoder.
+VP8StatusCode DecodeWebPIncremental(
+    const uint8_t* const data, size_t data_size,
+    WebPDecoderConfig* const config);
+
+//------------------------------------------------------------------------------
+
+// Decodes a WebP contained in 'data', returning the decoded output in 'pic'.
+// Output is RGBA or YUVA, depending on pic->use_argb value.
+// If 'keep_alpha' is true and the WebP has an alpha channel, the output is RGBA
+// or YUVA. Otherwise, alpha channel is dropped and output is RGB or YUV.
+// Returns true on success.
+int ReadWebP(const uint8_t* const data, size_t data_size,
+             struct WebPPicture* const pic,
+             int keep_alpha, struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_WEBPDEC_H_
--- a/external/libwebp/libwebp/imageio/wicdec.c
+++ b/external/libwebp/libwebp/imageio/wicdec.c
@@ -0,0 +1,413 @@
+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Windows Imaging Component (WIC) decode.
+
+#include "./wicdec.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+#ifdef HAVE_WINCODEC_H
+#ifdef __MINGW32__
+#define INITGUID  // Without this GUIDs are declared extern and fail to link
+#endif
+#define CINTERFACE
+#define COBJMACROS
+#define _WIN32_IE 0x500  // Workaround bug in shlwapi.h when compiling C++
+                         // code with COBJMACROS.
+#include <ole2.h>  // CreateStreamOnHGlobal()
+#include <shlwapi.h>
+#include <tchar.h>
+#include <windows.h>
+#include <wincodec.h>
+
+#include "../examples/unicode.h"
+#include "./imageio_util.h"
+#include "./metadata.h"
+#include "webp/encode.h"
+
+#define IFS(fn)                                                     \
+  do {                                                              \
+    if (SUCCEEDED(hr)) {                                            \
+      hr = (fn);                                                    \
+      if (FAILED(hr)) fprintf(stderr, #fn " failed %08lx\n", hr);   \
+    }                                                               \
+  } while (0)
+
+// modified version of DEFINE_GUID from guiddef.h.
+#define WEBP_DEFINE_GUID(name, l, w1, w2, b1, b2, b3, b4, b5, b6, b7, b8) \
+  static const GUID name = \
+      { l, w1, w2, { b1, b2,  b3,  b4,  b5,  b6,  b7,  b8 } }
+
+#ifdef __cplusplus
+#define MAKE_REFGUID(x) (x)
+#else
+#define MAKE_REFGUID(x) &(x)
+#endif
+
+typedef struct WICFormatImporter {
+  const GUID* pixel_format;
+  int bytes_per_pixel;
+  int (*import)(WebPPicture* const, const uint8_t* const, int);
+} WICFormatImporter;
+
+// From Microsoft SDK 7.0a -- wincodec.h
+// Create local copies for compatibility when building against earlier
+// versions of the SDK.
+WEBP_DEFINE_GUID(GUID_WICPixelFormat24bppBGR_,
+                 0x6fddc324, 0x4e03, 0x4bfe,
+                 0xb1, 0x85, 0x3d, 0x77, 0x76, 0x8d, 0xc9, 0x0c);
+WEBP_DEFINE_GUID(GUID_WICPixelFormat24bppRGB_,
+                 0x6fddc324, 0x4e03, 0x4bfe,
+                 0xb1, 0x85, 0x3d, 0x77, 0x76, 0x8d, 0xc9, 0x0d);
+WEBP_DEFINE_GUID(GUID_WICPixelFormat32bppBGRA_,
+                 0x6fddc324, 0x4e03, 0x4bfe,
+                 0xb1, 0x85, 0x3d, 0x77, 0x76, 0x8d, 0xc9, 0x0f);
+WEBP_DEFINE_GUID(GUID_WICPixelFormat32bppRGBA_,
+                 0xf5c7ad2d, 0x6a8d, 0x43dd,
+                 0xa7, 0xa8, 0xa2, 0x99, 0x35, 0x26, 0x1a, 0xe9);
+WEBP_DEFINE_GUID(GUID_WICPixelFormat64bppBGRA_,
+                 0x1562ff7c, 0xd352, 0x46f9,
+                 0x97, 0x9e, 0x42, 0x97, 0x6b, 0x79, 0x22, 0x46);
+WEBP_DEFINE_GUID(GUID_WICPixelFormat64bppRGBA_,
+                 0x6fddc324, 0x4e03, 0x4bfe,
+                 0xb1, 0x85, 0x3d, 0x77, 0x76, 0x8d, 0xc9, 0x16);
+
+static HRESULT OpenInputStream(const char* filename, IStream** stream) {
+  HRESULT hr = S_OK;
+  if (!WSTRCMP(filename, "-")) {
+    const uint8_t* data = NULL;
+    size_t data_size = 0;
+    const int ok = ImgIoUtilReadFile(filename, &data, &data_size);
+    if (ok) {
+      HGLOBAL image = GlobalAlloc(GMEM_MOVEABLE, data_size);
+      if (image != NULL) {
+        void* const image_mem = GlobalLock(image);
+        if (image_mem != NULL) {
+          memcpy(image_mem, data, data_size);
+          GlobalUnlock(image);
+          IFS(CreateStreamOnHGlobal(image, TRUE, stream));
+        } else {
+          hr = E_FAIL;
+        }
+      } else {
+        hr = E_OUTOFMEMORY;
+      }
+      free((void*)data);
+    } else {
+      hr = E_FAIL;
+    }
+  } else {
+    IFS(SHCreateStreamOnFile((const LPTSTR)filename, STGM_READ, stream));
+  }
+
+  if (FAILED(hr)) {
+    _ftprintf(stderr, _T("Error opening input file %s (%08lx)\n"),
+              (const LPTSTR)filename, hr);
+  }
+  return hr;
+}
+
+// -----------------------------------------------------------------------------
+// Metadata processing
+
+// Stores the first non-zero sized color profile from 'frame' to 'iccp'.
+// Returns an HRESULT to indicate success or failure. The caller is responsible
+// for freeing 'iccp->bytes' in either case.
+static HRESULT ExtractICCP(IWICImagingFactory* const factory,
+                           IWICBitmapFrameDecode* const frame,
+                           MetadataPayload* const iccp) {
+  HRESULT hr = S_OK;
+  UINT i, count;
+  IWICColorContext** color_contexts;
+
+  IFS(IWICBitmapFrameDecode_GetColorContexts(frame, 0, NULL, &count));
+  if (FAILED(hr) || count == 0) {
+    // Treat unsupported operation as a non-fatal error. See crbug.com/webp/506.
+    return (hr == WINCODEC_ERR_UNSUPPORTEDOPERATION) ? S_OK : hr;
+  }
+
+  color_contexts = (IWICColorContext**)calloc(count, sizeof(*color_contexts));
+  if (color_contexts == NULL) return E_OUTOFMEMORY;
+  for (i = 0; SUCCEEDED(hr) && i < count; ++i) {
+    IFS(IWICImagingFactory_CreateColorContext(factory, &color_contexts[i]));
+  }
+
+  if (SUCCEEDED(hr)) {
+    UINT num_color_contexts;
+    IFS(IWICBitmapFrameDecode_GetColorContexts(frame,
+                                               count, color_contexts,
+                                               &num_color_contexts));
+    assert(FAILED(hr) || num_color_contexts <= count);
+    for (i = 0; SUCCEEDED(hr) && i < num_color_contexts; ++i) {
+      WICColorContextType type;
+      IFS(IWICColorContext_GetType(color_contexts[i], &type));
+      if (SUCCEEDED(hr) && type == WICColorContextProfile) {
+        UINT size;
+        IFS(IWICColorContext_GetProfileBytes(color_contexts[i],
+                                             0, NULL, &size));
+        if (SUCCEEDED(hr) && size > 0) {
+          iccp->bytes = (uint8_t*)malloc(size);
+          if (iccp->bytes == NULL) {
+            hr = E_OUTOFMEMORY;
+            break;
+          }
+          iccp->size = size;
+          IFS(IWICColorContext_GetProfileBytes(color_contexts[i],
+                                               (UINT)iccp->size, iccp->bytes,
+                                               &size));
+          if (SUCCEEDED(hr) && size != iccp->size) {
+            fprintf(stderr, "Warning! ICC profile size (%u) != expected (%u)\n",
+                    size, (uint32_t)iccp->size);
+            iccp->size = size;
+          }
+          break;
+        }
+      }
+    }
+  }
+  for (i = 0; i < count; ++i) {
+    if (color_contexts[i] != NULL) IUnknown_Release(color_contexts[i]);
+  }
+  free(color_contexts);
+  return hr;
+}
+
+static HRESULT ExtractMetadata(IWICImagingFactory* const factory,
+                               IWICBitmapFrameDecode* const frame,
+                               Metadata* const metadata) {
+  // TODO(jzern): add XMP/EXIF extraction.
+  const HRESULT hr = ExtractICCP(factory, frame, &metadata->iccp);
+  if (FAILED(hr)) MetadataFree(metadata);
+  return hr;
+}
+
+// -----------------------------------------------------------------------------
+
+static int HasPalette(GUID pixel_format) {
+  return (IsEqualGUID(MAKE_REFGUID(pixel_format),
+                      MAKE_REFGUID(GUID_WICPixelFormat1bppIndexed)) ||
+          IsEqualGUID(MAKE_REFGUID(pixel_format),
+                      MAKE_REFGUID(GUID_WICPixelFormat2bppIndexed)) ||
+          IsEqualGUID(MAKE_REFGUID(pixel_format),
+                      MAKE_REFGUID(GUID_WICPixelFormat4bppIndexed)) ||
+          IsEqualGUID(MAKE_REFGUID(pixel_format),
+                      MAKE_REFGUID(GUID_WICPixelFormat8bppIndexed)));
+}
+
+static int HasAlpha(IWICImagingFactory* const factory,
+                    IWICBitmapDecoder* const decoder,
+                    IWICBitmapFrameDecode* const frame,
+                    GUID pixel_format) {
+  int has_alpha;
+  if (HasPalette(pixel_format)) {
+    IWICPalette* frame_palette = NULL;
+    IWICPalette* global_palette = NULL;
+    BOOL frame_palette_has_alpha = FALSE;
+    BOOL global_palette_has_alpha = FALSE;
+
+    // A palette may exist at the frame or container level,
+    // check IWICPalette::HasAlpha() for both if present.
+    if (SUCCEEDED(IWICImagingFactory_CreatePalette(factory, &frame_palette)) &&
+        SUCCEEDED(IWICBitmapFrameDecode_CopyPalette(frame, frame_palette))) {
+      IWICPalette_HasAlpha(frame_palette, &frame_palette_has_alpha);
+    }
+    if (SUCCEEDED(IWICImagingFactory_CreatePalette(factory, &global_palette)) &&
+        SUCCEEDED(IWICBitmapDecoder_CopyPalette(decoder, global_palette))) {
+      IWICPalette_HasAlpha(global_palette, &global_palette_has_alpha);
+    }
+    has_alpha = frame_palette_has_alpha || global_palette_has_alpha;
+
+    if (frame_palette != NULL) IUnknown_Release(frame_palette);
+    if (global_palette != NULL) IUnknown_Release(global_palette);
+  } else {
+    has_alpha = IsEqualGUID(MAKE_REFGUID(pixel_format),
+                            MAKE_REFGUID(GUID_WICPixelFormat32bppRGBA_)) ||
+                IsEqualGUID(MAKE_REFGUID(pixel_format),
+                            MAKE_REFGUID(GUID_WICPixelFormat32bppBGRA_)) ||
+                IsEqualGUID(MAKE_REFGUID(pixel_format),
+                            MAKE_REFGUID(GUID_WICPixelFormat64bppRGBA_)) ||
+                IsEqualGUID(MAKE_REFGUID(pixel_format),
+                            MAKE_REFGUID(GUID_WICPixelFormat64bppBGRA_));
+  }
+  return has_alpha;
+}
+
+int ReadPictureWithWIC(const char* const filename,
+                       WebPPicture* const pic, int keep_alpha,
+                       Metadata* const metadata) {
+  // From Microsoft SDK 6.0a -- ks.h
+  // Define a local copy to avoid link errors under mingw.
+  WEBP_DEFINE_GUID(GUID_NULL_, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
+  static const WICFormatImporter kAlphaFormatImporters[] = {
+    { &GUID_WICPixelFormat32bppBGRA_, 4, WebPPictureImportBGRA },
+    { &GUID_WICPixelFormat32bppRGBA_, 4, WebPPictureImportRGBA },
+    { NULL, 0, NULL },
+  };
+  static const WICFormatImporter kNonAlphaFormatImporters[] = {
+    { &GUID_WICPixelFormat24bppBGR_, 3, WebPPictureImportBGR },
+    { &GUID_WICPixelFormat24bppRGB_, 3, WebPPictureImportRGB },
+    { NULL, 0, NULL },
+  };
+  HRESULT hr = S_OK;
+  IWICBitmapFrameDecode* frame = NULL;
+  IWICFormatConverter* converter = NULL;
+  IWICImagingFactory* factory = NULL;
+  IWICBitmapDecoder* decoder = NULL;
+  IStream* stream = NULL;
+  UINT frame_count = 0;
+  UINT width = 0, height = 0;
+  BYTE* rgb = NULL;
+  WICPixelFormatGUID src_pixel_format = GUID_WICPixelFormatUndefined;
+  const WICFormatImporter* importer = NULL;
+  GUID src_container_format = GUID_NULL_;
+  // From Windows Kits\10\Include\10.0.19041.0\um\wincodec.h
+  WEBP_DEFINE_GUID(GUID_ContainerFormatWebp_,
+                   0xe094b0e2, 0x67f2, 0x45b3,
+                   0xb0, 0xea, 0x11, 0x53, 0x37, 0xca, 0x7c, 0xf3);
+  static const GUID* kAlphaContainers[] = {
+    &GUID_ContainerFormatBmp,
+    &GUID_ContainerFormatPng,
+    &GUID_ContainerFormatTiff,
+    &GUID_ContainerFormatWebp_,
+    NULL
+  };
+  int has_alpha = 0;
+  int64_t stride;
+
+  if (filename == NULL || pic == NULL) return 0;
+
+  IFS(CoInitialize(NULL));
+  IFS(CoCreateInstance(MAKE_REFGUID(CLSID_WICImagingFactory), NULL,
+                       CLSCTX_INPROC_SERVER,
+                       MAKE_REFGUID(IID_IWICImagingFactory),
+                       (LPVOID*)&factory));
+  if (hr == REGDB_E_CLASSNOTREG) {
+    fprintf(stderr,
+            "Couldn't access Windows Imaging Component (are you running "
+            "Windows XP SP3 or newer?). Most formats not available. "
+            "Use -s for the available YUV input.\n");
+  }
+  // Prepare for image decoding.
+  IFS(OpenInputStream(filename, &stream));
+  IFS(IWICImagingFactory_CreateDecoderFromStream(
+          factory, stream, NULL,
+          WICDecodeMetadataCacheOnDemand, &decoder));
+  IFS(IWICBitmapDecoder_GetFrameCount(decoder, &frame_count));
+  if (SUCCEEDED(hr)) {
+    if (frame_count == 0) {
+      fprintf(stderr, "No frame found in input file.\n");
+      hr = E_FAIL;
+    } else if (frame_count > 1) {
+      // WIC will be tried before native WebP decoding so avoid duplicating the
+      // error message.
+      hr = E_FAIL;
+    }
+  }
+  IFS(IWICBitmapDecoder_GetFrame(decoder, 0, &frame));
+  IFS(IWICBitmapFrameDecode_GetPixelFormat(frame, &src_pixel_format));
+  IFS(IWICBitmapDecoder_GetContainerFormat(decoder, &src_container_format));
+
+  if (SUCCEEDED(hr) && keep_alpha) {
+    const GUID** guid;
+    for (guid = kAlphaContainers; *guid != NULL; ++guid) {
+      if (IsEqualGUID(MAKE_REFGUID(src_container_format),
+                      MAKE_REFGUID(**guid))) {
+        has_alpha = HasAlpha(factory, decoder, frame, src_pixel_format);
+        break;
+      }
+    }
+  }
+
+  // Prepare for pixel format conversion (if necessary).
+  IFS(IWICImagingFactory_CreateFormatConverter(factory, &converter));
+
+  for (importer = has_alpha ? kAlphaFormatImporters : kNonAlphaFormatImporters;
+       hr == S_OK && importer->import != NULL; ++importer) {
+    BOOL can_convert;
+    const HRESULT cchr = IWICFormatConverter_CanConvert(
+        converter,
+        MAKE_REFGUID(src_pixel_format),
+        MAKE_REFGUID(*importer->pixel_format),
+        &can_convert);
+    if (SUCCEEDED(cchr) && can_convert) break;
+  }
+  if (importer->import == NULL) hr = E_FAIL;
+
+  IFS(IWICFormatConverter_Initialize(converter, (IWICBitmapSource*)frame,
+                                     importer->pixel_format,
+                                     WICBitmapDitherTypeNone,
+                                     NULL, 0.0, WICBitmapPaletteTypeCustom));
+
+  // Decode.
+  IFS(IWICFormatConverter_GetSize(converter, &width, &height));
+  stride = (int64_t)importer->bytes_per_pixel * width * sizeof(*rgb);
+  if (stride != (int)stride ||
+      !ImgIoUtilCheckSizeArgumentsOverflow(stride, height)) {
+    hr = E_FAIL;
+  }
+
+  if (SUCCEEDED(hr)) {
+    rgb = (BYTE*)malloc((size_t)stride * height);
+    if (rgb == NULL)
+      hr = E_OUTOFMEMORY;
+  }
+  IFS(IWICFormatConverter_CopyPixels(converter, NULL,
+                                     (UINT)stride, (UINT)stride * height, rgb));
+
+  // WebP conversion.
+  if (SUCCEEDED(hr)) {
+    int ok;
+    pic->width = width;
+    pic->height = height;
+    pic->use_argb = 1;    // For WIC, we always force to argb
+    ok = importer->import(pic, rgb, (int)stride);
+    if (!ok) hr = E_FAIL;
+  }
+  if (SUCCEEDED(hr)) {
+    if (metadata != NULL) {
+      hr = ExtractMetadata(factory, frame, metadata);
+      if (FAILED(hr)) {
+        fprintf(stderr, "Error extracting image metadata using WIC!\n");
+      }
+    }
+  }
+
+  // Cleanup.
+  if (converter != NULL) IUnknown_Release(converter);
+  if (frame != NULL) IUnknown_Release(frame);
+  if (decoder != NULL) IUnknown_Release(decoder);
+  if (factory != NULL) IUnknown_Release(factory);
+  if (stream != NULL) IUnknown_Release(stream);
+  free(rgb);
+  return SUCCEEDED(hr);
+}
+#else  // !HAVE_WINCODEC_H
+int ReadPictureWithWIC(const char* const filename,
+                       struct WebPPicture* const pic, int keep_alpha,
+                       struct Metadata* const metadata) {
+  (void)filename;
+  (void)pic;
+  (void)keep_alpha;
+  (void)metadata;
+  fprintf(stderr, "Windows Imaging Component (WIC) support not compiled. "
+                  "Visual Studio and mingw-w64 builds support WIC. Make sure "
+                  "wincodec.h detection is working correctly if using autoconf "
+                  "and HAVE_WINCODEC_H is defined before building.\n");
+  return 0;
+}
+#endif  // HAVE_WINCODEC_H
+
+// -----------------------------------------------------------------------------
--- a/external/libwebp/libwebp/imageio/wicdec.h
+++ b/external/libwebp/libwebp/imageio/wicdec.h
@@ -0,0 +1,34 @@
+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Windows Imaging Component (WIC) decode.
+
+#ifndef WEBP_IMAGEIO_WICDEC_H_
+#define WEBP_IMAGEIO_WICDEC_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct Metadata;
+struct WebPPicture;
+
+// Reads an image from 'filename', returning the decoded output in 'pic'.
+// If 'keep_alpha' is true and the image has an alpha channel, the output is
+// RGBA otherwise it will be RGB. pic->use_argb is always forced to true.
+// Returns true on success.
+int ReadPictureWithWIC(const char* const filename,
+                       struct WebPPicture* const pic, int keep_alpha,
+                       struct Metadata* const metadata);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_IMAGEIO_WICDEC_H_
--- a/external/libwebp/libwebp/infra/common.sh
+++ b/external/libwebp/libwebp/infra/common.sh
@@ -0,0 +1,106 @@
+# Copyright (c) 2021, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#
+#   * Neither the name of Google nor the names of its contributors may
+#     be used to endorse or promote products derived from this software
+#     without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+log_err() {
+  echo "[$(date +'%Y-%m-%dT%H:%M:%S%z')]: $*" >&2
+}
+
+#######################################
+# Create build directory. Build directory will be deleted if it exists.
+# Arguments:
+#   None.
+# Returns:
+#   mkdir result.
+#######################################
+make_build_dir() {
+  if [[ "$#" -ne 1 ]]; then
+    return 1
+  fi
+
+  local build_dir
+  build_dir="$1"
+  rm -rf "${build_dir}"
+  mkdir -p "${build_dir}"
+}
+
+#######################################
+# Cleanup files from the build directory.
+# Globals:
+#   LIBWEBP_ROOT repository's root path.
+# Arguments:
+#   $1 build directory.
+#######################################
+cleanup() {
+  # $1 is not completely removed to allow for binary artifacts to be
+  # extracted.
+  find "${1:?"Build directory not defined"}" \
+    \( -name "*.[ao]" -o -name "*.l[ao]" \) -exec rm -f {} +
+}
+
+#######################################
+# Setup ccache for toolchain.
+# Globals:
+#   PATH
+# Arguments:
+#   None.
+#######################################
+setup_ccache() {
+  if [[ -x "$(command -v ccache)" ]]; then
+    export CCACHE_CPP2=yes
+    export PATH="/usr/lib/ccache:${PATH}"
+  fi
+}
+
+#######################################
+# Detects whether test block should be run in the current test shard.
+# Globals:
+#   TEST_TOTAL_SHARDS: Valid range: [1, N]. Defaults to 1.
+#   TEST_SHARD_INDEX: Valid range: [0, TEST_TOTAL_SHARDS). Defaults to 0.
+#   libwebp_test_id: current test number; incremented with each call.
+# Arguments:
+#   None
+# Returns:
+#   true if the shard is active
+#   false if the shard is inactive
+#######################################
+shard_should_run() {
+  TEST_TOTAL_SHARDS=${TEST_TOTAL_SHARDS:=1}
+  TEST_SHARD_INDEX=${TEST_SHARD_INDEX:=0}
+  libwebp_test_id=${libwebp_test_id:=-1}
+  : $((libwebp_test_id += 1))
+
+  if [[ "${TEST_SHARD_INDEX}" -lt 0 ||
+    "${TEST_SHARD_INDEX}" -ge "${TEST_TOTAL_SHARDS}" ]]; then
+    log_err "Invalid TEST_SHARD_INDEX (${TEST_SHARD_INDEX})!" \
+      "Expected [0, ${TEST_TOTAL_SHARDS})."
+  fi
+
+  [[ "$((libwebp_test_id % TEST_TOTAL_SHARDS))" -eq "${TEST_SHARD_INDEX}" ]]
+}
--- a/external/libwebp/libwebp/infra/compile.sh
+++ b/external/libwebp/libwebp/infra/compile.sh
@@ -0,0 +1,401 @@
+#!/bin/bash
+# Copyright (c) 2021, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#
+#   * Neither the name of Google nor the names of its contributors may
+#     be used to endorse or promote products derived from this software
+#     without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+set -xe
+LIBWEBP_ROOT="$(realpath "$(dirname "$0")/..")"
+WORKSPACE=${WORKSPACE:-"$(mktemp -d -t webp.XXX)"}
+
+# shellcheck source=infra/common.sh
+source "${LIBWEBP_ROOT}/infra/common.sh"
+
+usage() {
+  cat << EOF
+Usage: compile.sh BUILD_TYPE TARGET
+Options:
+BUILD_TYPE  supported build type: (shared, static, static-debug)
+TARGET      supported target platforms:
+              aarch64-linux-clang
+              aarch64-linux-gnu
+              arm-linux-gnueabi
+              arm-neon-linux-gnueabi
+              cmake
+              cmake-aarch64
+              cmake-arm
+              cmake-clang
+              disable-near-lossless
+              disable-sse4.1
+              disable-stats
+              force-aligned-32
+              force-aligned-64
+              gradle
+              i686-linux-asan
+              i686-linux-clang
+              i686-linux-gnu
+              i686-w64-mingw32
+              mips2el-linux-gnu
+              mips32dspr2el-linux-gnu
+              mips32eb-linux-gnu
+              mips32el-linux-gnu
+              mips32r2el-linux-gnu
+              mips32r5el-linux-gnu
+              mips64r2el-linux-gnu
+              mips64r6el-linux-gnu
+              native
+              reduce-csp
+              reduce-size
+              reduce-size-disable-stats
+              visibility-default-gnu
+              visibility-hidden-clang
+              visibility-hidden-gnu
+              wasm
+              x86_64-linux-clang
+              x86_64-linux-gnu
+              x86_64-linux-msan
+              x86_64-w64-mingw32
+Environment variables:
+WORKSPACE   directory where the build is done
+EOF
+}
+
+################################################################################
+echo "Building libwebp in ${WORKSPACE}"
+
+if [[ ! -d "${WORKSPACE}" ]]; then
+  log_err "${WORKSPACE} directory does not exist"
+  exit 1
+fi
+
+BUILD_TYPE=${1:?"Build type not defined.$(
+  echo
+  usage
+)"}
+TARGET=${2:?"Target not defined.$(
+  echo
+  usage
+)"}
+readonly BUILD_DIR="${WORKSPACE}/build-${BUILD_TYPE}"
+
+trap 'cleanup ${BUILD_DIR}' EXIT
+make_build_dir "${BUILD_DIR}"
+
+config_flags=()
+case "${BUILD_TYPE}" in
+  shared*) ;;  # Valid BUILD_TYPE but no setup required
+  static*) config_flags+=("--disable-shared") ;;
+  experimental) config_flags+=("--enable-experimental") ;;
+  *)
+    log_err "Invalid BUILD_TYPE"
+    usage
+    exit 1
+    ;;
+esac
+
+if grep -m 1 -q "enable-asserts" "${LIBWEBP_ROOT}/configure.ac"; then
+  config_flags+=("--enable-asserts")
+fi
+
+case "${TARGET}" in
+  aarch64-linux-clang)
+    TARGET="aarch64-linux-gnu"
+    CC="clang"
+    CC="${CC} --target=aarch64-linux-gnu"
+    export CC
+    export CFLAGS="-isystem /usr/aarch64-linux-gnu/include"
+    ;;
+  arm-linux-gnueabi)
+    export CFLAGS="-O3 -march=armv7-a -mfloat-abi=softfp -ftree-vectorize"
+    ;;
+  arm-neon-linux-gnueabi)
+    TARGET="arm-linux-gnueabi"
+    CFLAGS="-O3 -march=armv7-a -mfpu=neon -mfloat-abi=softfp -ftree-vectorize"
+    export CFLAGS
+    ;;
+  mips2el-linux-gnu)
+    export CFLAGS="-EL -O2 -mips2"
+    TARGET="mipsel-linux-gnu"
+    ;;
+  mips32el-linux-gnu)
+    export CFLAGS="-EL -O2 -mips32"
+    TARGET="mipsel-linux-gnu"
+    ;;
+  mips32r2el-linux-gnu)
+    export CFLAGS="-EL -O2 -mips32r2"
+    TARGET="mipsel-linux-gnu"
+    ;;
+  mips32dspr2el-linux-gnu)
+    export CFLAGS="-EL -O2 -mdspr2"
+    TARGET="mipsel-linux-gnu"
+    ;;
+  mips32r5el-linux-gnu)
+    export CFLAGS="-EL -O2 -mips32r5 -mmsa"
+    TARGET="mipsel-linux-gnu"
+    ;;
+  mips32eb-linux-gnu)
+    export CFLAGS="-EB -O2 -mips32"
+    TARGET="mips-linux-gnu"
+    ;;
+  mips64r2el-linux-gnu)
+    export CFLAGS="-EL -O2 -mips64r2 -mabi=64"
+    TARGET="mips64el-linux-gnuabi64"
+    ;;
+  mips64r6el-linux-gnu)
+    export CFLAGS="-EL -O2 -mips64r6 -mabi=64 -mmsa"
+    TARGET="mips-img-linux-gnu"
+    ;;
+  i686-linux-gnu)
+    export CC="gcc -m32"
+    ;;
+  i686-linux-clang)
+    TARGET="i686-linux-gnu"
+    export CC="clang -m32"
+    ;;
+  i686-linux-asan)
+    TARGET="i686-linux-gnu"
+    export CC="clang -m32 -fsanitize=address"
+    ;;
+  i686-linux-msan)
+    TARGET="i686-linux-gnu"
+    export CC="clang -m32 -fsanitize=memory"
+    ;;
+  x86_64-linux-clang)
+    TARGET="x86_64-linux-gnu"
+    export CC=clang
+    ;;
+  x86_64-linux-msan)
+    TARGET="x86_64-linux-gnu"
+    export CC="clang -fsanitize=memory"
+    ;;
+  force-aligned-32)
+    config_flags+=("--enable-aligned")
+    TARGET="i686-linux-gnu"
+    export CC="gcc -m32"
+    ;;
+  force-aligned-64)
+    config_flags+=("--enable-aligned")
+    TARGET="x86_64-linux-gnu"
+    ;;
+  visibility-default-*)
+    export CFLAGS="-O2 -g -fvisibility=default"
+    TARGET="x86_64-linux-gnu"
+    ;;
+  visibility-hidden-*)
+    export CFLAGS="-O2 -g -fvisibility=hidden"
+    if [[ "${TARGET}" = "visibility-hidden-clang" ]]; then
+      export CC=clang
+    fi
+    TARGET="x86_64-linux-gnu"
+    ;;
+  disable-sse4.1)
+    grep "${TARGET}" "${LIBWEBP_ROOT}/configure.ac" || exit 0
+    config_flags+=("--${TARGET}")
+    TARGET="x86_64-linux-gnu"
+    ;;
+  disable-near-lossless)
+    grep "${TARGET}" "${LIBWEBP_ROOT}/configure.ac" || exit 0
+    config_flags+=("--${TARGET}")
+    TARGET="x86_64-linux-gnu"
+    ;;
+  disable-stats)
+    git -C "${LIBWEBP_ROOT}" grep WEBP_DISABLE_STATS || exit 0
+    export CFLAGS="-O2 -g -DWEBP_DISABLE_STATS"
+    TARGET="x86_64-linux-gnu"
+    ;;
+  reduce-size)
+    git -C "${LIBWEBP_ROOT}" grep WEBP_REDUCE_SIZE || exit 0
+    export CFLAGS="-O2 -g -DWEBP_REDUCE_SIZE"
+    TARGET="x86_64-linux-gnu"
+    ;;
+  reduce-size-disable-stats)
+    git -C "${LIBWEBP_ROOT}" grep -e WEBP_DISABLE_STATS -e WEBP_REDUCE_SIZE \
+      || exit 0
+    export CFLAGS="-O2 -g -DWEBP_DISABLE_STATS -DWEBP_REDUCE_SIZE"
+    TARGET="x86_64-linux-gnu"
+    ;;
+  reduce-csp)
+    git -C "${LIBWEBP_ROOT}" grep WEBP_REDUCE_CSP || exit 0
+    export CFLAGS="-O2 -g -DWEBP_REDUCE_CSP"
+    TARGET="x86_64-linux-gnu"
+    ;;
+  x86_64-linux-gnu | *mingw32 | aarch64*) ;;  # Default target configuration
+  # non-configure based builds
+  native)
+    setup_ccache
+    # exercise makefile.unix then quit
+    make -C "${LIBWEBP_ROOT}" -f makefile.unix -j all
+    for tgt in extras examples/anim_diff; do
+      grep -q -m 1 "${tgt}" "${LIBWEBP_ROOT}/makefile.unix" \
+        && make -C "${LIBWEBP_ROOT}" -f makefile.unix -j "${tgt}"
+    done
+    [[ -d "${LIBWEBP_ROOT}/tests/fuzzer" ]] \
+      && make -j -C "${LIBWEBP_ROOT}/tests/fuzzer" -f makefile.unix
+    exit 0
+    ;;
+  cmake*)
+    setup_ccache
+    # exercise cmake then quit
+    opts=()
+    case "${TARGET}" in
+      cmake-clang)
+        opts+=("-DCMAKE_C_COMPILER=clang")
+        ;;
+      cmake-arm)
+        opts+=("-DCMAKE_C_COMPILER=arm-linux-gnueabi-gcc")
+        case "${GERRIT_BRANCH:-}" in
+          portable-intrinsics | 0.6.1) exit 0 ;;
+          *) ;;  # Skip configuration
+        esac
+        ;;
+      cmake-aarch64)
+        opts+=("-DCMAKE_C_COMPILER=aarch64-linux-gnu-gcc")
+        case "${GERRIT_BRANCH:-}" in
+          portable-intrinsics | 0.6.1) exit 0 ;;
+          *) ;;  # Skip configuration
+        esac
+        ;;
+      *) ;;  # Skip configuration
+    esac
+    case "${BUILD_TYPE}" in
+      static*)
+        opts+=("-DBUILD_SHARED_LIBS=OFF")
+        ;;
+      experimental)
+        opts+=("-DWEBP_EXPERIMENTAL_FEATURES=ON" "-DBUILD_SHARED_LIBS=ON")
+        ;;
+      *)
+        opts+=("-DBUILD_SHARED_LIBS=ON")
+        ;;
+    esac
+    case "${BUILD_TYPE}" in
+      *debug) opts+=("-DCMAKE_BUILD_TYPE=Debug") ;;
+      *) opts+=("-DCMAKE_BUILD_TYPE=RelWithDebInfo") ;;
+    esac
+    cd "${BUILD_DIR}"
+    opts+=("-DWEBP_BUILD_CWEBP=ON" "-DWEBP_BUILD_DWEBP=ON")
+    grep -m 1 -q WEBP_BUILD_GIF2WEBP "${LIBWEBP_ROOT}/CMakeLists.txt" \
+      && opts+=("-DWEBP_BUILD_GIF2WEBP=ON")
+    grep -m 1 -q WEBP_BUILD_IMG2WEBP "${LIBWEBP_ROOT}/CMakeLists.txt" \
+      && opts+=("-DWEBP_BUILD_IMG2WEBP=ON")
+    cmake "${opts[@]}" "${LIBWEBP_ROOT}"
+    make VERBOSE=1 -j
+    case "${BUILD_TYPE}" in
+      static)
+        mkdir -p examples
+        cp [cd]webp examples
+        ;;
+      *) ;;  # Skip configuration.
+    esac
+
+    grep "install" "${LIBWEBP_ROOT}/CMakeLists.txt" || exit 0
+
+    make DESTDIR="${BUILD_DIR}/webp-install" install/strip
+    mkdir tmp
+    cd tmp
+    cat > CMakeLists.txt << EOF
+cmake_minimum_required(VERSION 2.8.7)
+
+project(libwebp C)
+
+find_package(WebP)
+if (NOT WebP_FOUND)
+  message(FATAL_ERROR "WebP package not found")
+endif ()
+message("WebP_FOUND: \${WebP_FOUND}")
+message("WebP_INCLUDE_DIRS: \${WebP_INCLUDE_DIRS}")
+message("WebP_LIBRARIES: \${WebP_LIBRARIES}")
+message("WEBP_INCLUDE_DIRS: \${WEBP_INCLUDE_DIRS}")
+message("WEBP_LIBRARIES: \${WEBP_LIBRARIES}")
+EOF
+    cmake . "${opts[@]}" \
+      "-DCMAKE_PREFIX_PATH=${BUILD_DIR}/webp-install/usr/local"
+    exit 0
+    ;;
+  gradle)
+    setup_ccache
+    # exercise gradle then quit
+    [[ -f "${LIBWEBP_ROOT}/gradlew" ]] || exit 0
+
+    cd "${BUILD_DIR}"
+    # TODO -g / --gradle-user-home could be used if there's a race between jobs
+    "${LIBWEBP_ROOT}/gradlew" -p "${LIBWEBP_ROOT}" buildAllExecutables
+    exit 0
+    ;;
+  wasm)
+    grep -m 1 -q WEBP_ENABLE_WASM "${LIBWEBP_ROOT}/CMakeLists.txt" || exit 0
+    opts+=("-DCMAKE_C_COMPILER=clang" "-DWEBP_ENABLE_WASM=ON")
+    opts+=("-DWEBP_BUILD_CWEBP=ON" "-DWEBP_BUILD_DWEBP=ON")
+    case "${BUILD_TYPE}" in
+      *debug) opts+=("-DCMAKE_BUILD_TYPE=Debug") ;;
+      *) opts+=("-DCMAKE_BUILD_TYPE=RelWithDebInfo") ;;
+    esac
+    cd "${BUILD_DIR}"
+    cmake "${opts[@]}" "${LIBWEBP_ROOT}"
+    make VERBOSE=1 -j
+    mkdir examples
+    case "${BUILD_TYPE}" in
+      static)
+        mkdir -p examples
+        cp [cd]webp examples
+        ;;
+      *) ;;  # Skip configuration
+    esac
+    exit 0
+    ;;
+  *)
+    log_err "Invalid TARGET"
+    usage
+    exit 1
+    ;;
+esac
+
+case "${TARGET}" in
+  *mingw32) ;;  # Skip configuration
+  *)
+    case "${TARGET}-${CC}" in
+      static-debug-gcc* | static-debug-)
+        CFLAGS="${CFLAGS} -fprofile-arcs -ftest-coverage -O0 -g"
+        CXXFLAGS="${CXXFLAGS} -fprofile-arcs -ftest-coverage -O0 -g"
+        export CFLAGS CXXFLAGS
+        ;;
+      *) ;;  # This case should not be reached.
+    esac
+    ;;
+esac
+
+setup_ccache
+
+cd "${LIBWEBP_ROOT}"
+./autogen.sh
+
+cd "${BUILD_DIR}"
+"${LIBWEBP_ROOT}/configure" \
+  --host "${TARGET}" --build "$("${LIBWEBP_ROOT}/config.guess")" \
+  --enable-everything "${config_flags[@]}"
+make -j V=1
--- a/external/libwebp/libwebp/infra/compile_android.sh
+++ b/external/libwebp/libwebp/infra/compile_android.sh
@@ -0,0 +1,224 @@
+#!/bin/bash
+# Copyright (c) 2021, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#
+#   * Neither the name of Google nor the names of its contributors may
+#     be used to endorse or promote products derived from this software
+#     without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+set -xe
+LIBWEBP_ROOT="$(realpath "$(dirname "$0")/..")"
+readonly LIBWEBP_ROOT
+readonly WORKSPACE=${WORKSPACE:-"$(mktemp -d -t webp.android.XXX)"}
+# shellcheck source=infra/common.sh
+source "${LIBWEBP_ROOT}/infra/common.sh"
+
+usage() {
+  cat << EOF
+Usage: $(basename "$0") BUILD_TYPE APP_ABI
+Options:
+BUILD_TYPE  supported build types:
+              static
+              static-debug
+              shared
+              shared-debug
+APP_ABI     supported application binary interfaces:
+              armeabi-v7a
+              arm64-v8a
+              x86
+              x86_64
+Environment variables:
+WORKSPACE   directory where the build is done.
+ANDROID_NDK_DIR directory where the android ndk tools are.
+EOF
+}
+
+################################################################################
+echo "Building libwebp for Android in ${WORKSPACE}"
+
+if [[ ! -d "${WORKSPACE}" ]]; then
+  log_err "${WORKSPACE} directory does not exist."
+  exit 1
+fi
+
+readonly BUILD_TYPE=${1:?"BUILD_TYPE is not defined.$(
+  echo
+  usage
+)"}
+readonly APP_ABI=${2:?"APP_ABI not defined.$(
+  echo
+  usage
+)"}
+readonly ANDROID_NDK_DIR=${ANDROID_NDK_DIR:?"ANDROID_NDK_DIR is not defined.$(
+  echo
+  usage
+)"}
+readonly BUILD_DIR="${WORKSPACE}/build-${BUILD_TYPE}"
+readonly STANDALONE_ANDROID_DIR="${WORKSPACE}/android"
+
+if [[ ! -x "${ANDROID_NDK_DIR}/ndk-build" ]]; then
+  log_err "unable to find ndk-build in ANDROID_NDK_DIR: ${ANDROID_NDK_DIR}."
+  exit 1
+fi
+
+CFLAGS=
+LDFLAGS=
+opts=()
+case "${BUILD_TYPE}" in
+  *debug)
+    readonly APP_OPTIM="debug"
+    CFLAGS="-O0 -g"
+    opts+=("--enable-asserts")
+    ;;
+  static* | shared*)
+    readonly APP_OPTIM="release"
+    CFLAGS="-O2 -g"
+    ;;
+  *)
+    usage
+    exit 1
+    ;;
+esac
+
+case "${BUILD_TYPE}" in
+  shared*) readonly SHARED="1" ;;
+  *)
+    readonly SHARED="0"
+    CFLAGS="${CFLAGS} -fPIE"
+    LDFLAGS="${LDFLAGS} -Wl,-pie"
+    opts+=("--disable-shared")
+    ;;
+esac
+
+# Create a fresh build directory
+make_build_dir "${BUILD_DIR}"
+cd "${BUILD_DIR}"
+ln -s "${LIBWEBP_ROOT}" jni
+
+"${ANDROID_NDK_DIR}/ndk-build" -j2 \
+  APP_ABI="${APP_ABI}" \
+  APP_OPTIM="${APP_OPTIM}" \
+  ENABLE_SHARED="${SHARED}"
+
+cd "${LIBWEBP_ROOT}"
+./autogen.sh
+
+case "${APP_ABI}" in
+  armeabi*) arch="arm" ;;
+  arm64*) arch="arm64" ;;
+  *) arch="${APP_ABI}" ;;
+esac
+# TODO(b/185520507): remove this and use the binaries from
+# toolchains/llvm/prebuilt/ directly.
+rm -rf "${STANDALONE_ANDROID_DIR}"
+"${ANDROID_NDK_DIR}/build/tools/make_standalone_toolchain.py" \
+  --api 24 --arch "${arch}" --stl gnustl --install-dir \
+  "${STANDALONE_ANDROID_DIR}"
+export PATH="${STANDALONE_ANDROID_DIR}/bin:${PATH}"
+
+rm -rf "${BUILD_DIR}"
+make_build_dir "${BUILD_DIR}"
+cd "${BUILD_DIR}"
+
+case "${arch}" in
+  arm)
+    host="arm-linux-androideabi"
+    case "${APP_ABI}" in
+      armeabi) ;;
+      armeabi-v7a)
+        CFLAGS="${CFLAGS} -march=armv7-a -mfpu=neon -mfloat-abi=softfp"
+        ;;
+      *) ;;  # No configuration needed
+    esac
+    ;;
+  arm64)
+    host="aarch64-linux-android"
+    ;;
+  x86)
+    host="i686-linux-android"
+    ;;
+  x86_64)
+    host="x86_64-linux-android"
+    ;;
+  *) ;;  # Skip configuration
+esac
+
+setup_ccache
+CC="clang"
+
+"${LIBWEBP_ROOT}/configure" --host "${host}" --build \
+  "$("${LIBWEBP_ROOT}/config.guess")" CC="${CC}" CFLAGS="${CFLAGS}" \
+  LDFLAGS="${LDFLAGS}" "${opts[@]}"
+make -j
+
+if [[ "${GERRIT_REFSPEC:-}" = "refs/heads/portable-intrinsics" ]] \
+  || [[ "${GERRIT_BRANCH:-}" = "portable-intrinsics" ]]; then
+  cd "${WORKSPACE}"
+  rm -rf build && mkdir build
+  cd build
+  standalone="${WORKSPACE}/android"
+  cmake ../libwebp \
+    -DWEBP_BUILD_DWEBP=1 \
+    -DCMAKE_C_COMPILER="${standalone}/bin/clang" \
+    -DCMAKE_PREFIX_PATH="${standalone}/sysroot/usr/lib" \
+    -DCMAKE_C_FLAGS=-fPIE \
+    -DCMAKE_EXE_LINKER_FLAGS=-Wl,-pie \
+    -DCMAKE_BUILD_TYPE=Release \
+    -DWEBP_ENABLE_WASM=1
+  make -j2
+
+  cd "${WORKSPACE}"
+  make_build_dir "${BUILD_DIR}"
+  cd "${BUILD_DIR}"
+  case "${APP_ABI}" in
+    armeabi-v7a | arm64*)
+      cmake "${LIBWEBP_ROOT}" \
+        -DWEBP_BUILD_DWEBP=1 \
+        -DCMAKE_C_COMPILER="${standalone}/bin/clang" \
+        -DCMAKE_PREFIX_PATH="${standalone}/sysroot/usr/lib" \
+        -DCMAKE_C_FLAGS='-fPIE -DENABLE_NEON_BUILTIN_MULHI_INT16X8' \
+        -DCMAKE_EXE_LINKER_FLAGS=-Wl,-pie \
+        -DCMAKE_BUILD_TYPE=Release \
+        -DWEBP_ENABLE_WASM=1
+      make -j2
+      ;;
+    x86*)
+      cmake "${LIBWEBP_ROOT}" \
+        -DWEBP_BUILD_DWEBP=1 \
+        -DCMAKE_C_COMPILER="${standalone}/bin/clang" \
+        -DCMAKE_PREFIX_PATH="${standalone}/sysroot/usr/lib" \
+        -DCMAKE_C_FLAGS='-fPIE -DENABLE_X86_BUILTIN_MULHI_INT16X8' \
+        -DCMAKE_EXE_LINKER_FLAGS=-Wl,-pie \
+        -DCMAKE_BUILD_TYPE=Release \
+        -DWEBP_ENABLE_WASM=1
+      make -j2
+      ;;
+    *)
+      log_err "APP_ABI not supported."
+      exit 1
+      ;;
+  esac
+fi
--- a/external/libwebp/libwebp/infra/compile_js.sh
+++ b/external/libwebp/libwebp/infra/compile_js.sh
@@ -0,0 +1,75 @@
+#!/bin/bash
+# Copyright (c) 2021, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#
+#   * Neither the name of Google nor the names of its contributors may
+#     be used to endorse or promote products derived from this software
+#     without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+set -ex
+
+readonly WORKSPACE="${WORKSPACE:-"$(mktemp -d -t webp.js.XXX)"}"
+readonly BUILD_DIR="${WORKSPACE}/webp_js/"
+readonly LIBWEBP_ROOT="$(realpath "$(dirname "$0")/..")"
+
+# shellcheck source=infra/common.sh
+source "${LIBWEBP_ROOT}/infra/common.sh"
+
+usage() {
+  cat << EOF
+Usage: $(basename "$0")
+Environment variables:
+WORKSPACE directory where the build is done
+EMSDK_DIR directory where emsdk is installed
+EOF
+}
+
+[[ -d "${EMSDK_DIR:?Not defined}" ]] \
+  || (log_err "${EMSDK_DIR} is not a valid directory." && exit 1)
+
+# shellcheck source=/opt/emsdk/emsdk_env.sh
+source "${EMSDK_DIR}/emsdk_env.sh"
+
+readonly EMSCRIPTEN=${EMSCRIPTEN:-"${EMSDK}/upstream/emscripten"}
+readonly \
+  EMSCRIPTEN_CMAKE_FILE="${EMSCRIPTEN}/cmake/Modules/Platform/Emscripten.cmake"
+make_build_dir "${BUILD_DIR}"
+
+pushd "${BUILD_DIR}"
+opts=("-GUnix Makefiles" "-DWEBP_BUILD_WEBP_JS=ON")
+if [[ -z "$(command -v emcmake)" ]]; then
+  opts+=("-DCMAKE_TOOLCHAIN_FILE=${EMSCRIPTEN_CMAKE_FILE}")
+  cmake \
+    "${opts[@]}" \
+    "${LIBWEBP_ROOT}"
+  make -j
+else
+  emcmake cmake \
+    "${opts[@]}" \
+    "${LIBWEBP_ROOT}"
+  emmake make -j
+fi
+popd
--- a/external/libwebp/libwebp/infra/run_static_analysis.sh
+++ b/external/libwebp/libwebp/infra/run_static_analysis.sh
@@ -0,0 +1,98 @@
+#!/bin/bash
+# Copyright (c) 2021, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#   * Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#
+#   * Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in
+#     the documentation and/or other materials provided with the
+#     distribution.
+#
+#   * Neither the name of Google nor the names of its contributors may
+#     be used to endorse or promote products derived from this software
+#     without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+set -xe
+
+LIBWEBP_ROOT="$(realpath "$(dirname "$0")/..")"
+readonly LIBWEBP_ROOT
+readonly WORKSPACE=${WORKSPACE:-"$(mktemp -d -t webp.scanbuild.XXX)"}
+
+# shellcheck source=infra/common.sh
+source "${LIBWEBP_ROOT}/infra/common.sh"
+
+usage() {
+  cat << EOF
+Usage: $(basename "$0") MODE
+Options:
+MODE supported scan modes: (shallow|deep)
+Environment variables:
+WORKSPACE directory where the build is done.
+EOF
+}
+
+#######################################
+# Wrap clang-tools scan-build.
+# Globals:
+#   OUTPUT_DIR target directory where scan-build report is generated.
+#   MODE scan-build mode
+# Arguments:
+#   $* scan-build additional args.
+# Returns:
+#   scan-build retcode
+#######################################
+scan_build() {
+  scan-build -o "${OUTPUT_DIR}" --use-analyzer="$(command -v clang)" \
+    -analyzer-config mode="${MODE}" "$*"
+}
+
+MODE=${1:?"MODE is not specified.$(
+  echo
+  usage
+)"}
+
+readonly OUTPUT_DIR="${WORKSPACE}/output-${MODE}"
+readonly BUILD_DIR="${WORKSPACE}/build"
+
+make_build_dir "${OUTPUT_DIR}"
+make_build_dir "${BUILD_DIR}"
+
+cd "${LIBWEBP_ROOT}"
+./autogen.sh
+
+cd "${BUILD_DIR}"
+grep -m 1 -q 'enable-asserts' "${LIBWEBP_ROOT}/configure.ac" \
+    && args='--enable-asserts'
+scan_build "${LIBWEBP_ROOT}/configure" --enable-everything "${args}"
+scan_build make -j4
+
+index="$(find "${OUTPUT_DIR}" -name index.html)"
+if [[ -f "${index}" ]]; then
+  mv "$(dirname "${index}")/"* "${OUTPUT_DIR}"
+else
+  # make a empty report to wipe out any old bug reports.
+  cat << EOT > "${OUTPUT_DIR}/index.html"
+<html>
+<body>
+No bugs reported.
+</body>
+</html>
+EOT
+fi
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Green Sky	0b46b891c2	add simple quote message context menu	2023-09-01 21:13:36 +02:00
Green Sky	d131b5a02f	add hacky way to load encrypted tox saves	2023-08-28 15:33:36 +02:00
Green Sky	9d9a486537	limit fps to 60 and disable imgui demo window	2023-08-28 14:06:27 +02:00
Green Sky	610ed10011	scope plugin paths	2023-08-20 12:50:58 +02:00
Green Sky	4edab11616	update deps and dont try to load files >50mib as images	2023-08-19 21:42:47 +02:00
Green Sky	6df0417667	update sdl Merge commit '4d48f9d23713d94b861da7b5d41baf2a41334994'	2023-08-12 20:17:29 +02:00
Green Sky	4d48f9d237	Squashed 'external/sdl/SDL/' changes from b8d91252c6..ec0042081e ec0042081e Add .gitattributes file a5d9db0cd0 cmake: build tests for UWP b7889a7389 winrt: use windowsio in non-libc mode ea8757a748 Make testaudiostreamdynamicresample compatible with emscripten 1a7a74fb2e cmake: build emscripten tests as html page 64d570f027 Add minimal http server for emscripten test apps 8e898c4a21 SDL_test does not parse --samples argument 91cd5478be audio: Fix resampler overflowing input buffer. f290c85b22 testaudiocapture: Make sure we convert captured audio to output format. b75c751dfc rwlock: Make generic implmentations work on single-threaded platforms. 80850af7ce The controller update complete events are no longer disabled by default 3f486224a9 Fixed refresh rate calculation for KMSDRM 342ec51131 Fix overflow when doing SDL_sscanf("%hd", ...) 9129e1d557 Fixed crash when setting the default cursor twice 8e99a4f4f5 Undo variable rename be67f0de10 Fixed crashes related to the default cursor on WinRT and KMSDRM 94b3f78c44 Fix out of bound read of 'has_hat' array 94f48f19b0 Use more specific build destinations when creating an xcframework dabd45997e Back out change supporting multiple names for binding elements efe15588d5 Relabel back paddles as left or right be884f0c95 ci: disable visionos.yml by renaming the file ac094d00f5 ci: add workflow_dispatch event to visionos workflow 9be9e2292b build: Consistently use pathlib APIs in cmake/xxd.py a9f6950657 Fixed deadlock shutting down Android sensors d9f09e77f2 Actually make the sensors magical! 690eae7d22 Implement visionOS support e385d6da0a Fixed build warning 6b93e788fa Improved sensor thread-safety 4ee0e5a984 Fixed thread-safety warnings 12deed91f8 Added information on how to enable thread-safety analysis 5735d2b03b coreaudio: Fixed assertion when device fails/quits mid-iteration. 1022fd6e04 testaudio: the test framework opens an audio device at startup; close it. 0714da37a4 audio: Fix audio stream callback calculations when future buffer has space. 917e036f6f MSVC has __declspec(deprecated) 279ff8909f Changed example code to avoid potential divide by zero 8a1afc9b10 Fixed Android not sending controller event timestamps 463c456b98 Fill the correct member with the joystick ID in SDL_EVENT_JOYSTICK_UPDATE_COMPLETE 55cf1abaa6 test: Don't flag testsurround as suitable for non-interactive use a2d594269c Fixed pixel format compatibility with SDL2 79a190aa23 Fixed setting invalid bpp for FOURCC formats in SDL_GetMasksForPixelFormatEnum() 8fdebdd3e0 Sync SDL3 wiki -> header b903ccf945 SDL_rwops read/write functions return size_t again c03f5b4b69 Fixed rounding up in SDL_PrintFloat 75a020aa6b Only query serial number and firmware versions from Sony PS5 controllers fa189d302e Added the Victrix Pro FS for PS4/PS5 to the controller list 26205b659d Fixed PS4/PS5 touchpad for third party controllers 6af0448af9 include: fixed a typo in SDL_RenderGetMetalCommandEncoder docs. f3cb46b083 SDL_thread.h: do not conflict with sdl2-compat::sdl3_include_wrapper.h 080b1dfbdb Revert "Improved fallback for SDL_COMPILE_TIME_ASSERT() (thanks @icculus!)" 9d453daa23 Improved fallback for SDL_COMPILE_TIME_ASSERT() (thanks @icculus!) 1fb2419882 Removed reference to renamed function e7d56dd0b2 audio: Renamed new API SDL_UnpauseAudioDevice to SDL_ResumeAudioDevice. 2b0c0f5b6b Don't pass NULL to strncmp 778e8185cd Fix size of memcpy in SDL_AudioDeviceFormatChangedAlreadyLocked And add diagnostic that allows to find this kind of issue in clang-tidy 4bb426abad Sync SDL3 wiki -> header 3a752ce650 Reapply "Changed 'freesrc' parameter from int to SDL_bool" to SDL_wave.c 2ba03b4db0 fix build after previous commit. 0026adffd4 apply force_align_arg_pointer attribute to correct version of SDL_RunApp 77446e2029 Unaligned stacks on i686-w64-mingw32 may lead to crashes d3bcc3f057 Fixed build errors when OpenGL isn't enabled 35ad68e126 Sync SDL3 wiki -> header 70323a8350 Add a function to display the system menu for a window be5f66c84e testaudio: Fixed soundboard icon, which had a colorkey issue. c0a88930bf Sync SDL3 wiki -> header 18c59cc969 Merge the SDL3 audio subsystem redesign! 99b0e31788 The Steam Controller D-Pad is only pressed when the button is pressed down 103073d694 Set NSBluetoothAlwaysUsageDescription for testcontroller ca02bb6c8c We don't need testdropfile-Info.plist e063f662e9 Enable the controller update complete events 06bea1eb55 Added a gamepad mapping for the G-Shark GS-GP702 5ca3c50bf0 testaudio: Fix compiler warning. 1b1f02c5aa testaudio: Apparently compilers don't like this possibly being NULL now...? 2de9253b6c test: Added testaudio fb3ab3f113 SDL_video.c: move ngage video before offscreen. 843572d993 Don't mark autorelease keys as virtual 648de4f9b8 Fixed duplicate key press/release events on iOS a8abe612ed Only pass keypresses up the responder chain when text input is active c3288d113e Synchronize on-screen keyboard state with text input active state 5fb92ef2f7 Fixed whitespace f5ea6ae18d Revert "Stop beep when running iOS apps on ARM-based Macs" 546508b9b4 Allow test programs to run at full resolution on iPads 68a4bb01e0 Allocate displays as an array of pointers instead of an array of objects 07578fde3d Fixed crash if a display is enumerated twice a509771a87 fix ios CI workflow after commit e4460e897f 72ce76905a The scheme isn't always the same as the framework name (e.g. xmp_lite vs xmp-lite) e4460e897f By default Xcode expects the framework target name to be the name of the project. ac683773dc Added missing tests to the "All" target 7dd56eaafe Removed unnecessary reference to testoverlay-Info.plist e1c7f524ef Reduce the number of times SDL3 is duplicated in the xcframework script 65538011ca Make Xcode targets more specific efe114c300 Revert "Renamed the xcframework target from "SDL.xcframework" to "xcframework"" 73ed1d21a9 Renamed the xcframework target from "SDL.xcframework" to "xcframework" 76b4d8a0d8 Build the Framework instead of a static library for iOS and tvOS d1bf979160 Removed unnecessary setting from the "Create DMG" target c94cb3a5d8 Simplified the Xcode project to a single Framework target ea60474c65 cmake: don't build SDL3-static Apple framework 8f00d7856d Sync SDL3 wiki -> header d4a867a256 Rename SDL_GetPath to SDL_GetUserFolder 71099149b8 Fall back to Xlib if XRandR isn't available b7f32f74ce Note the removal of the SDL_RENDERER_TARGETTEXTURE flag 0eda582160 testaudiostreamdynamicresample: Load sample.wav correctly. 87eae9a0a1 aaudio: We need a mixbuf on capture devices, too. fb68e84646 wayland: Fix memory leaks b0edd23c00 testsurround: Log available audio output devices at the start. ae3090c387 androidaudio: Move Init/bootstrap code to bottom of source code. 18fc0db9e5 aaudio: Rearranged source code to match other backends. 2507c1d68b aaudio: Disconnect playing devices if error callback fires. 32a3fc3783 aaudio: Use the callback interface. b49ce86765 audio: Fixed compiler warning on Android NDK. 1c074e8d97 android: Fixed audio device detection. 82ce05ad01 pulseaudio: Be more aggressive with hotplug thread synchronization. 5cbdf1168e androidaudio: Fixed incorrect JNI call (thanks, @madebr!) 660054f3dc include: Correct comment about audio device hotplug events. ab68428a64 aaudio: Fixed for older SDKs and Android releases. 5ff87c6d4a android: Reworked audio backends for SDL3 audio API. 54af687210 testautomation_audio.c: Patched to compile. :/ 5e82090662 testautomation_audio.c: Apparently we aren't updating test code for C99 atm. 7f4488f625 wasapi: More fixes for Clang warnings. 29a0c689c9 wasapi: Patched to compile with Clang. 4aa95c21bc pspaudio: Patched to compile. 9a2a0a1463 ps2audio: Delete errant character that got inserted before previous commit. 2c578bd0d5 qnxaudio: Rewrite for SDL3 audio APIs. 455eef4cd9 audio: Use AtomicAdd for device counts, don't treat as a refcount. 095ea57f94 pspaudio: Patched to compile. d7cf63db67 ps2audio: Patched to compile. 027b9e8787 coreaudio: (maybe) patched to compile on iOS. 4836c2db07 pspaudio: Patched to compile. 86ca412436 n3dsaudio: Patched to compile. 66bcee2ca9 testaudiostreamdynamicresample.c: Fixed MSVC compiler warning. dbf993d358 vitaaudio: patched to compile. 5707e14716 audio: Fix up some things that broke when rebasing the branch against main. 6567285eae SDL_migration.cocci: Fix up SDL_(Pause\|Unpause)Audio. 0b6255551e test: Fixed incorrect SDL_OpenAudioDevice call in testautomation. 107fd941cd vitaaudio: Clean up correctly in CloseDevice. 9fa4a6ef87 netbsdaudio: Minor fix. b0d89868c6 n3dsaudio: Updated (but untested!) for SDL3 audio API. ba27176106 vitaaudio: Untested attempt to move Vita audio to SDL3's audio API. 0b58e96d9e wasapi: Patched WinRT to compile. d6b4f48488 visualc: Turn on multiprocessor compilation. c58d95c343 wasapi: Reworked for new SDL3 audio API, other win32 fixes. dc04f85646 audio: whoops, that should be an int. be0dc630b7 audio: Fixed incorrect assertion 77b3fb06ee directsound: First shot at updating for SDL3 audio API. 4399b71715 audio: Generalize how backends can lookup an SDL_AudioDevice. 2fb122fe46 audio: backends now "find" instead of "obtain" devices by handle. c3f5a5fc72 dummyaudio: SDL3ify style 7d65ff86e2 diskaudio: Adjusted for later SDL3 audio API redesign changes. 4ba9c2eade dummyaudio: Configurable delay, other SDL3 API fixes. fb395d3ad7 sndio: Updated to the SDL3 audio API. 1a55282051 dsp: Some minor logic fixes 6bc85577d7 netbsdaudio: Updated for SDL3 audio API. 0f6e59312b netbsdaudio: Removed email address from source code. 51ae78c0af haikuaudio: Updated for SDL3 audio API. fc7ed18ca1 emscriptenaudio: don't forget to finalize the audio thread 4233c41ce2 pulseaudio: Removed unnecessary variable. a0528cd5ed emscriptenaudio: Updated for SDL3 audio API. 79cc29ba35 wave: Don't check if format->channels > INT_MAX, it's a Uint16. 1bfe97c235 pspaudio: Updated for SDL3 audio API. 121a2dce15 audio: Make sure `device->hidden` is NULL after CloseDevice 3d6ba0cafd ps2audio: Removed free of buffer that hasn't been allocated yet. 00ed6f8827 test: Fixed compiler warnings for unused vars. 6f12f68ec9 ps2audio: SDL3ified the style 4993743a02 ps2audio: Renamed `_this` to `device` 74568cdb2b ps2audio: Updated (but untested) for SDL3 audio API. c83b68ef26 jack: renamed `_this` to `device`. 3f4f004794 audio: Remove an assertion that no longer makes sense. 86243b2589 jack: Use ProvidesOwnCallbackThread. 18906a32b8 jack: First shot at updating for SDL3 audio API. a2b488359e dsp: Removed debug logging 6fd71185cd dsp: Updated for new SDL3 audio API. 3482d1215a alsa: Don't ever block in CaptureFromDevice. 65d296ef1a audio: Use SDL_powerof2 instead of reinventing it. 409b544505 alsa: Updated for new SDL3 audio API 0999a090a7 audio: More tweaking of `device->thread_alive` f94ffd6092 audio: Fixed logic error 4deb2970c9 alsa: Renamed `_this` to `device` 0fb9e4baae audio: Remove no-longer-used SupportsNonPow2Samples c653e57768 coreaudio: rewritten for SDL3 audio redesign! 533777eff5 audio: SDL_sysaudio.h comment conversion. 8473e522e0 audio: unify device thread naming. 258bc9efed audio: PlayDevice now passes the buffer, too, for convenience. e518149d14 audio: Fixed locking in SDL_AudioDeviceDisconnected 22afa5735f audio: FreeDeviceHandle should pass the whole device, for convenience. 9e3c5f93e0 coreaudio: Change `_this` to `device` e969160de0 audio: unset a freed variable to NULL 1fc01b0300 audio: Try to definitely have a default device set up. b60a56d368 audio: take first reported device if no default was specified. a8323ebe68 audio: Better handling of ProvidesOwnCallbackThread backends. 1dffb72c1d pipewire: Hooked up default device change notifications. a93fcf2444 audio: fixed flushed stream reporting bytes but not being able to get them. ad6c1781fc pulseaudio: Minor cleanups. cfc8a0d17d pipewire: First shot at moving to the new SDL3 audio interfaces. 13202642a3 aaudio: Fixed capitialization, plus some minor cleanups. 3e9991b535 audio: Make sure we don't write to a NULL pointer. 943351affb pulseaudio: GetDefaultAudioInfo isn't a thing anymore. 11dfc4d737 test: Update testautomation_audio for SDL3 audio API. 29afc2e42b test: Update testresample for SDL3 audio API. 3a02eecced test: Update testsurround for SDL3 audio API. e1c78718d4 test: testaudiocapture is updated for the SDL3 audio API. f48cb716c2 pulseaudio: a couple minor tweaks. dac25fe9eb audio: Seperate audio capture into Wait/Read operations. 3e10c0005d audio: Capture devices should respect logical device pausing. 7e700531c5 audio: Allow SDL_OpenAudioDevice to accept a NULL spec. bb1cbbd33a test: Update testaudioinfo for SDL3 audio API. 883aee32c5 audio: Let default formats differ for output and capture devices. 62cf24eeb9 pulseaudio: Listen for server events in addition to sources and sinks. 924f370bd7 pulseaudio: Fix deadlock in HotplugThread. 5d4e9e5f80 test: Updated testaudiostreamdynamicresample to SDL3 audio API. f883b9fc64 test: Updated testaudiohotplug to SDL3 audio API. 2be5f726d4 audio: Removed debug logging. 323ecce123 docs: Added migration note about SDL_AUDIODEVICEREMOVED. 47b0321ebf test: Removed loopwavequeue.c; obsolete in SDL3. 0e5a1d4f29 pulseaudio: Removed debug logging. f598626e46 test: loopwave shouldn't use an audiostream callback. eee407caf8 docs: migration guide note that SDL_LoadWAV has a different return type. b03c493fc4 test: Updated testmultiaudio to new SDL3 audio API fe1daf6fb5 audio: Mark disconnected default devices as "zombies". cdd2ba81de audio: Fixed adding new physical devices to a double-linked list. db39cbf208 audio: Allow SDL_GetAudioDeviceFormat() to query the default devices. ee10bab3cd audio: An enormous amount of work on managing default devices. c7a44eea83 audio: Fixed logic error. 089cd87cb5 audio: Make sure device count stays correct as hardware disconnects. e50cb72eb6 docs: Note that audio opening doesn't implicitly init SDL now. 97b2f747d0 docs: Corrections to audio section of README-migration.md 464640440f audio: Added SDL_GetAudioStreamBinding. 01f7b53865 audio: Readded (logical) device pausing. fd4c9f4e11 audio: documentation improvements. 4b78b789a7 audio: Switch SDL_audio.c and SDL_audiocvt.c to C99-ish syntax. d96a1db7d7 audio: Opening via a logical device ID should also track default device. b2e020958f audio: Wrap device access in opening of logical devices. 7ee2459927 audio: Check for unlikely failure case in WAV loaded. 3d65a2cefe audio: Made SDL_LoadWAV a real function, not just a macro. 26525f5fd3 audio: Readd SDL_AudioSpec, but just with format/channels/freq fields. e6aaed7d79 include: Audio is not, and has not been, a raw mixing buffer for a long time. 56b1bc2198 audio: SDL_AudioStream now has callbacks for Get and Put operations. 905c4fff5b audio: First shot at the SDL3 audio subsystem redesign! b221b59995 cmake: add SDL_REVISION option 0500fca00c Add missing break d3f2de7f29 fixed typo in prev. patch. 12b35c6a46 test/testnativecocoa.m: fixed deprecation warnings. e24b3e2fa4 cmake: rename SDL_TEST -> SDL_TEST_LIBRARY da5016d336 cmake: use pkg-config + test compile instead of Find module for detecting rpi deec574ff6 cmake: fix SDL_HIDAPI_LIBUSB f2ae00c1ad Sync SDL3 wiki -> header 41a96c8133 doc: document building of SDL tests with CMake 3174d0b970 Sorted controller list 27b8abb056 Add Steam Deck controller mapping to database. 41d436f0fe Use SetWindowPos to show windows when SDL_HINT_WINDOW_ACTIVATE_WHEN_SHOWN is set to avoid activating the parent window when showing a child window 0dc85f3078 Improved the documentation for the gamepad paddle buttons 2fff999a41 Try to create the dummy mouse cursor after video backend initialization d086d9874d Sync SDL3 wiki -> header bce598addd SDL_pixels.c: Fixed compiler warning on Android NDK. ad0c0d3cde Sync SDL3 wiki -> header f8e8dff7ee tests: Fix automated window grab and positioning tests under Wayland/XWayland 4cffbc3644 Add VS code directory to gitignore 666f81bace Add more endian-specific aliases for 32 bit pixelformats 4749df0a63 Just disable the 4214 warning instead of trying to change the structure definition git-subtree-dir: external/sdl/SDL git-subtree-split: ec0042081ea104d5dd0ee291105210e00a4fe3d9	2023-08-12 20:17:29 +02:00
Green Sky	bd9bbf67d4	small fixes	2023-08-11 12:18:50 +02:00
Green Sky	8cab1307ab	update sub	2023-08-09 11:18:41 +02:00
Green Sky	5bfc429450	small ui refactor + forwarding files	2023-08-06 16:07:50 +02:00
Green Sky	7a7b55bebf	make tox save file selectable (hacky)	2023-08-03 15:03:12 +02:00
Green Sky	b4eda033c6	update plugin version	2023-08-03 13:11:59 +02:00
Green Sky	c9672bf352	add debug start screen ui + can load plugins	2023-08-03 13:05:19 +02:00
Green Sky	5547ff6d2b	also scen media on message creation	2023-08-02 20:58:16 +02:00
Green Sky	ea8cc85c61	update subs for tox reconnection bug fixes	2023-08-02 20:21:06 +02:00
Green Sky	5ecec26731	image inlining working	2023-08-02 19:24:51 +02:00
Green Sky	01fddd19cd	message texture cache + message image loader (no inline images yet)	2023-08-02 16:36:34 +02:00
Green Sky	e362af8271	cleanup texures on cache destruction	2023-08-02 15:37:37 +02:00
Green Sky	2dba4f8fbb	add webp support	2023-08-02 15:06:19 +02:00
Green Sky	bdfe44399a	Merge commit '67653bbe50841153bfeaebcc5792bd8464da9880' as 'external/libwebp/libwebp'	2023-08-02 14:57:22 +02:00
Green Sky	67653bbe50	Squashed 'external/libwebp/libwebp/' content from commit dd7364c3c git-subtree-dir: external/libwebp/libwebp git-subtree-split: dd7364c3cefe0f5c0b3c18c3b1887d353f90fc1f	2023-08-02 14:57:22 +02:00
Green Sky	a144459e8d	add stb image loader (avatar png support)	2023-08-01 20:17:38 +02:00
Green Sky	d725ed8cd0	add stb	2023-08-01 20:13:38 +02:00
Green Sky	87d7eb69af	Merge commit '3cd551098b8dc5a2b55d45a2a63bb9a219d31f2e' as 'external/stb/stb'	2023-08-01 20:11:22 +02:00
Green Sky	3cd551098b	Squashed 'external/stb/stb/' content from commit c39c7023e git-subtree-dir: external/stb/stb git-subtree-split: c39c7023ebb833ce099750fe35509aca5662695e	2023-08-01 20:11:22 +02:00
Green Sky	95b77cb696	add avatar texture handling	2023-08-01 18:25:56 +02:00
Green Sky	2e28ad7bb9	fix missing include	2023-08-01 14:28:28 +02:00
Green Sky	75f78f8c7f	load tox identicons	2023-08-01 13:21:16 +02:00
Green Sky	ef59386e5c	start texture cache for contacts (avatars)	2023-07-31 20:47:22 +02:00
Green Sky	c0b57c30bd	add sdl bmp image loader	2023-07-30 16:00:55 +02:00
Green Sky	42b3866753	start thinking about pasting files	2023-07-30 15:10:26 +02:00
Green Sky	aff239377d	add README.md	2023-07-29 22:50:15 +02:00
Green Sky	3aaa1b0350	try satisfy macintosh	2023-07-29 22:30:36 +02:00
Green Sky	823a4ae189	missing include	2023-07-29 21:51:24 +02:00
Green Sky	40cd04f9dd	fix cross platform file paths to string	2023-07-29 21:25:25 +02:00
Green Sky	6a979d31a0	fix missing includes	2023-07-29 20:58:29 +02:00
Green Sky	56f7db9ae6	msg sorting	2023-07-29 20:51:32 +02:00
Green Sky	d5e2dd2e1f	add auto dirty (save toxfile) + minor stuff	2023-07-29 20:39:31 +02:00
Green Sky	93e5bb867b	invites	2023-07-29 20:07:59 +02:00
Green Sky	4cd295065b	add chat gui, probably works	2023-07-28 18:03:45 +02:00
Green Sky	5a9aacc603	add file selector with sorting	2023-07-27 19:34:47 +02:00
Green Sky	082c4febdf	more setup	2023-07-26 20:09:57 +02:00
Green Sky	a848a01527	add tox client and more setup	2023-07-26 12:55:50 +02:00
Green Sky	3a1c15f313	screen concept	2023-07-26 12:24:18 +02:00
Green Sky	e92c7cbfa0	add exe icon	2023-07-26 02:02:06 +02:00