Change the API to supply/return channel count and colorspace info

This commit is contained in:
Dominic Szablewski 2021-11-27 18:36:17 +01:00
parent 697abf6696
commit ff542c2ae6
4 changed files with 137 additions and 68 deletions

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@ -10,11 +10,14 @@ More info at https://phoboslab.org/log/2021/11/qoi-fast-lossless-image-compressi
⚠️ Please note that this library is not yet ready to deal with untrusted input. ⚠️ Please note that this library is not yet ready to deal with untrusted input.
⚠️ 2021.11.27 the specification for QOI has changed to accomodate some ⚠️ 2021.11.27 the specification for QOI has changed to accomodate some
concerns with the format. These specification changes are **not yet reflected in concerns with the format. If you are working on a QOI implementation, please
the code here**. If you are working on a QOI implementation, please refer to refer to
[#37 The QOI File Format Specification](https://github.com/phoboslab/qoi/issues/37) [#37 The QOI File Format Specification](https://github.com/phoboslab/qoi/issues/37)
for the details. for the details.
These specification changes are ~~not yet reflected in the code here~~
reflected in qoi.h now.
## Why? ## Why?

154
qoi.h
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@ -45,12 +45,21 @@ than stbi_image or libpng.
#define QOI_IMPLEMENTATION #define QOI_IMPLEMENTATION
#include "qoi.h" #include "qoi.h"
// Load and decode a QOI image from the file system into a 32bbp RGBA buffer // Encode and store an RGBA buffer to the file system. The qoi_desc describes
int width, height; // the input pixel data.
void *rgba_pixels = qoi_read("image.qoi", &width, &height, 4); qoi_write("image_new.qoi", rgba_pixels, &(qoi_desc){
.width = 1920,
.height = 1080,
.channels = 4,
.colorspace = QOI_SRGB
});
// Load and decode a QOI image from the file system into a 32bbp RGBA buffer.
// The qoi_desc struct will be filled with the width, height, number of channels
// and colorspace read from the file header.
qoi_desc desc;
void *rgba_pixels = qoi_read("image.qoi", &desc, 4);
// Encode and store an RGBA buffer to the file system
qoi_write("image_new.qoi", rgba_pixels, width, height, 4);
-- Documentation -- Documentation
@ -166,48 +175,75 @@ to check for an overrun once per decode loop iteration.
extern "C" { extern "C" {
#endif #endif
// A pointer to qoi_desc struct has to be supplied to all of qoi's functions. It
// describes either the input format (for qoi_write, qoi_encode), or is filled
// with the description read from the file header (for qoi_read, qoi_decode).
// The colorspace in this qoi_desc is a bitmap with 0000rgba where a 0-bit
// indicates sRGB and a 1-bit indicates linear colorspace for each channel. You
// may use one of the predefined constants: QOI_SRGB, QOI_SRGB_LINEAR_ALPHA or
// QOI_LINEAR. The colorspace is purely informative. It will be saved to the
// file header, but does not affect en-/decoding in any way.
#define QOI_SRGB 0x00
#define QOI_SRGB_LINEAR_ALPHA 0x01
#define QOI_LINEAR 0x0f
typedef struct {
unsigned int width;
unsigned int height;
unsigned char channels;
unsigned char colorspace;
} qoi_desc;
#ifndef QOI_NO_STDIO #ifndef QOI_NO_STDIO
// Encode raw RGB or RGBA pixels into a QOI image write it to the file system. // Encode raw RGB or RGBA pixels into a QOI image and write it to the file
// w and h denote the the width and height of the pixel data. channels must be // system. The qoi_desc struct must be filled with the image width, height,
// either 3 for RGB data or 4 for RGBA. // number of channels (3 = RGB, 4 = RGBA) and the colorspace.
// The function returns 0 on failure (invalid parameters, or fopen or malloc // The function returns 0 on failure (invalid parameters, or fopen or malloc
// failed) or the number of bytes written on success. // failed) or the number of bytes written on success.
int qoi_write(const char *filename, const void *data, int w, int h, int channels); int qoi_write(const char *filename, const void *data, const qoi_desc *desc);
// Read and decode a QOI image from the file system into either raw RGB // Read and decode a QOI image from the file system. If channels is 0, the
// (channels=3) or RGBA (channels=4) pixel data. // number of channels from the file header is used. If channels is 3 or 4 the
// output format will be forced into this number of channels.
// The function either returns NULL on failure (invalid data, or malloc or fopen // The function either returns NULL on failure (invalid data, or malloc or fopen
// failed) or a pointer to the decoded pixels. On success out_w and out_h will // failed) or a pointer to the decoded pixels. On success, the qoi_desc struct
// be set to the width and height of the decoded image. // will be filled with the description from the file header.
// The returned pixel data should be free()d after use. // The returned pixel data should be free()d after use.
void *qoi_read(const char *filename, int *out_w, int *out_h, int channels); void *qoi_read(const char *filename, qoi_desc *desc, int channels);
#endif // QOI_NO_STDIO #endif // QOI_NO_STDIO
// Encode raw RGB or RGBA pixels into a QOI image in memory. w and h denote the // Encode raw RGB or RGBA pixels into a QOI image in memory.
// width and height of the pixel data. channels must be either 3 for RGB data
// or 4 for RGBA.
// The function either returns NULL on failure (invalid parameters or malloc // The function either returns NULL on failure (invalid parameters or malloc
// failed) or a pointer to the encoded data on success. On success the out_len // failed) or a pointer to the encoded data on success. On success the out_len
// is set to the size in bytes of the encoded data. // is set to the size in bytes of the encoded data.
// The returned qoi data should be free()d after user. // The returned qoi data should be free()d after user.
void *qoi_encode(const void *data, int w, int h, int channels, int *out_len); void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len);
// Decode a QOI image from memory into either raw RGB (channels=3) or RGBA // Decode a QOI image from memory.
// (channels=4) pixel data.
// The function either returns NULL on failure (invalid parameters or malloc // The function either returns NULL on failure (invalid parameters or malloc
// failed) or a pointer to the decoded pixels. On success out_w and out_h will // failed) or a pointer to the decoded pixels. On success, the qoi_desc struct
// be set to the width and height of the decoded image. // is filled with the description from the file header.
// The returned pixel data should be free()d after use. // The returned pixel data should be free()d after use.
void *qoi_decode(const void *data, int size, int *out_w, int *out_h, int channels); void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels);
#ifdef __cplusplus #ifdef __cplusplus
} }
@ -265,17 +301,20 @@ unsigned int qoi_read_32(const unsigned char *bytes, int *p) {
return (a << 24) | (b << 16) | (c << 8) | d; return (a << 24) | (b << 16) | (c << 8) | d;
} }
void *qoi_encode(const void *data, int w, int h, int channels, int *out_len) { void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len) {
if ( if (
data == NULL || out_len == NULL || data == NULL || out_len == NULL || desc == NULL ||
w <= 0 || w >= (1 << 16) || desc->width == 0 || desc->height == 0 ||
h <= 0 || h >= (1 << 16) || desc->channels < 3 || desc->channels > 4 ||
channels < 3 || channels > 4 (desc->colorspace & 0xf0) != 0
) { ) {
return NULL; return NULL;
} }
int max_size = w * h * (channels + 1) + QOI_HEADER_SIZE + QOI_PADDING; int max_size =
desc->width * desc->height * (desc->channels + 1) +
QOI_HEADER_SIZE + QOI_PADDING;
int p = 0; int p = 0;
unsigned char *bytes = QOI_MALLOC(max_size); unsigned char *bytes = QOI_MALLOC(max_size);
if (!bytes) { if (!bytes) {
@ -283,10 +322,11 @@ void *qoi_encode(const void *data, int w, int h, int channels, int *out_len) {
} }
qoi_write_32(bytes, &p, QOI_MAGIC); qoi_write_32(bytes, &p, QOI_MAGIC);
qoi_write_32(bytes, &p, w); qoi_write_32(bytes, &p, desc->width);
qoi_write_32(bytes, &p, h); qoi_write_32(bytes, &p, desc->height);
bytes[p++] = channels; bytes[p++] = desc->channels;
bytes[p++] = 0; // TODO: accept a colorspace as a parameter to this function bytes[p++] = desc->colorspace;
const unsigned char *pixels = (const unsigned char *)data; const unsigned char *pixels = (const unsigned char *)data;
@ -295,11 +335,11 @@ void *qoi_encode(const void *data, int w, int h, int channels, int *out_len) {
int run = 0; int run = 0;
qoi_rgba_t px_prev = {.rgba = {.r = 0, .g = 0, .b = 0, .a = 255}}; qoi_rgba_t px_prev = {.rgba = {.r = 0, .g = 0, .b = 0, .a = 255}};
qoi_rgba_t px = px_prev; qoi_rgba_t px = px_prev;
int px_len = w * h * channels; int px_len = desc->width * desc->height * desc->channels;
int px_end = px_len - channels; int px_end = px_len - desc->channels;
for (int px_pos = 0; px_pos < px_len; px_pos += channels) { for (int px_pos = 0; px_pos < px_len; px_pos += desc->channels) {
if (channels == 4) { if (desc->channels == 4) {
px = *(qoi_rgba_t *)(pixels + px_pos); px = *(qoi_rgba_t *)(pixels + px_pos);
} }
else { else {
@ -382,8 +422,12 @@ void *qoi_encode(const void *data, int w, int h, int channels, int *out_len) {
return bytes; return bytes;
} }
void *qoi_decode(const void *data, int size, int *out_w, int *out_h, int channels) { void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels) {
if (channels < 3 || channels > 4 || size < QOI_HEADER_SIZE + QOI_PADDING) { if (
data == NULL || desc == NULL ||
(channels != 0 && channels != 3 && channels != 4) ||
size < QOI_HEADER_SIZE + QOI_PADDING
) {
return NULL; return NULL;
} }
@ -391,20 +435,24 @@ void *qoi_decode(const void *data, int size, int *out_w, int *out_h, int channel
int p = 0; int p = 0;
unsigned int header_magic = qoi_read_32(bytes, &p); unsigned int header_magic = qoi_read_32(bytes, &p);
unsigned int header_w = qoi_read_32(bytes, &p); desc->width = qoi_read_32(bytes, &p);
unsigned int header_h = qoi_read_32(bytes, &p); desc->height = qoi_read_32(bytes, &p);
unsigned int header_channels = bytes[p++]; desc->channels = bytes[p++];
unsigned int header_colorspace = bytes[p++]; desc->colorspace = bytes[p++];
if ( if (
header_w == 0 || header_h == 0 || desc->width == 0 || desc->height == 0 ||
header_channels < 3 || header_channels > 4 || desc->channels < 3 || desc->channels > 4 ||
header_magic != QOI_MAGIC header_magic != QOI_MAGIC
) { ) {
return NULL; return NULL;
} }
int px_len = header_w * header_h * channels; if (channels == 0) {
channels = desc->channels;
}
int px_len = desc->width * desc->height * channels;
unsigned char *pixels = QOI_MALLOC(px_len); unsigned char *pixels = QOI_MALLOC(px_len);
if (!pixels) { if (!pixels) {
return NULL; return NULL;
@ -471,17 +519,15 @@ void *qoi_decode(const void *data, int size, int *out_w, int *out_h, int channel
} }
} }
*out_w = header_w;
*out_h = header_h;
return pixels; return pixels;
} }
#ifndef QOI_NO_STDIO #ifndef QOI_NO_STDIO
#include <stdio.h> #include <stdio.h>
int qoi_write(const char *filename, const void *data, int w, int h, int channels) { int qoi_write(const char *filename, const void *data, const qoi_desc *desc) {
int size; int size;
void *encoded = qoi_encode(data, w, h, channels, &size); void *encoded = qoi_encode(data, desc, &size);
if (!encoded) { if (!encoded) {
return 0; return 0;
} }
@ -498,7 +544,7 @@ int qoi_write(const char *filename, const void *data, int w, int h, int channels
return size; return size;
} }
void *qoi_read(const char *filename, int *out_w, int *out_h, int channels) { void *qoi_read(const char *filename, qoi_desc *desc, int channels) {
FILE *f = fopen(filename, "rb"); FILE *f = fopen(filename, "rb");
if (!f) { if (!f) {
return NULL; return NULL;
@ -516,7 +562,7 @@ void *qoi_read(const char *filename, int *out_w, int *out_h, int channels) {
int bytes_read = fread(data, 1, size, f); int bytes_read = fread(data, 1, size, f);
fclose(f); fclose(f);
void *pixels = qoi_decode(data, bytes_read, out_w, out_h, channels); void *pixels = qoi_decode(data, bytes_read, desc, channels);
QOI_FREE(data); QOI_FREE(data);
return pixels; return pixels;
} }

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@ -350,7 +350,12 @@ benchmark_result_t benchmark_image(const char *path, int runs) {
// Load the encoded PNG, encoded QOI and raw pixels into memory // Load the encoded PNG, encoded QOI and raw pixels into memory
void *pixels = (void *)stbi_load(path, &w, &h, NULL, 4); void *pixels = (void *)stbi_load(path, &w, &h, NULL, 4);
void *encoded_png = fload(path, &encoded_png_size); void *encoded_png = fload(path, &encoded_png_size);
void *encoded_qoi = qoi_encode(pixels, w, h, 4, &encoded_qoi_size); void *encoded_qoi = qoi_encode(pixels, &(qoi_desc){
.width = w,
.height = h,
.channels = 4,
.colorspace = QOI_SRGB
}, &encoded_qoi_size);
if (!pixels || !encoded_qoi || !encoded_png) { if (!pixels || !encoded_qoi || !encoded_png) {
ERROR("Error decoding %s\n", path); ERROR("Error decoding %s\n", path);
@ -377,8 +382,8 @@ benchmark_result_t benchmark_image(const char *path, int runs) {
}); });
BENCHMARK_FN(runs, res.qoi.decode_time, { BENCHMARK_FN(runs, res.qoi.decode_time, {
int dec_w, dec_h; qoi_desc desc;
void *dec_p = qoi_decode(encoded_qoi, encoded_qoi_size, &dec_w, &dec_h, 4); void *dec_p = qoi_decode(encoded_qoi, encoded_qoi_size, &desc, 4);
free(dec_p); free(dec_p);
}); });
@ -400,7 +405,12 @@ benchmark_result_t benchmark_image(const char *path, int runs) {
BENCHMARK_FN(runs, res.qoi.encode_time, { BENCHMARK_FN(runs, res.qoi.encode_time, {
int enc_size; int enc_size;
void *enc_p = qoi_encode(pixels, w, h, 4, &enc_size); void *enc_p = qoi_encode(pixels, &(qoi_desc){
.width = w,
.height = h,
.channels = 4,
.colorspace = QOI_SRGB
}, &enc_size);
res.qoi.size = enc_size; res.qoi.size = enc_size;
free(enc_p); free(enc_p);
}); });

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@ -48,20 +48,24 @@ SOFTWARE.
int main(int argc, char **argv) { int main(int argc, char **argv) {
if (argc < 3) { if (argc < 3) {
printf("Usage: qoiconv infile outfile\n"); printf("Usage: qoiconv <infile> <outfile>\n");
printf("Examples:\n"); printf("Examples:\n");
printf(" qoiconv image.png image.qoi\n"); printf(" qoiconv input.png output.qoi\n");
printf(" qoiconv image.qoi image.png\n"); printf(" qoiconv input.qoi output.png\n");
exit(1); exit(1);
} }
void *pixels = NULL; void *pixels = NULL;
int w, h; int w, h, channels;
if (STR_ENDS_WITH(argv[1], ".png")) { if (STR_ENDS_WITH(argv[1], ".png")) {
pixels = (void *)stbi_load(argv[1], &w, &h, NULL, 4); pixels = (void *)stbi_load(argv[1], &w, &h, &channels, 0);
} }
else if (STR_ENDS_WITH(argv[1], ".qoi")) { else if (STR_ENDS_WITH(argv[1], ".qoi")) {
pixels = qoi_read(argv[1], &w, &h, 4); qoi_desc desc;
pixels = qoi_read(argv[1], &desc, 0);
channels = desc.channels;
w = desc.width;
h = desc.height;
} }
if (pixels == NULL) { if (pixels == NULL) {
@ -71,10 +75,15 @@ int main(int argc, char **argv) {
int encoded = 0; int encoded = 0;
if (STR_ENDS_WITH(argv[2], ".png")) { if (STR_ENDS_WITH(argv[2], ".png")) {
encoded = stbi_write_png(argv[2], w, h, 4, pixels, 0); encoded = stbi_write_png(argv[2], w, h, channels, pixels, 0);
} }
else if (STR_ENDS_WITH(argv[2], ".qoi")) { else if (STR_ENDS_WITH(argv[2], ".qoi")) {
encoded = qoi_write(argv[2], pixels, w, h, 4); encoded = qoi_write(argv[2], pixels, &(qoi_desc){
.width = w,
.height = h,
.channels = channels,
.colorspace = QOI_SRGB
});
} }
if (!encoded) { if (!encoded) {
@ -82,5 +91,6 @@ int main(int argc, char **argv) {
exit(1); exit(1);
} }
free(pixels);
return 0; return 0;
} }