tomato-testing/external/sdl/SDL/docs/README-wayland.md

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Wayland

Wayland is a replacement for the X11 window system protocol and architecture and is favored over X11 by default in SDL3 for communicating with desktop compositors. It works well for the majority of applications, however, applications may encounter limitations or behavior that is different from other windowing systems.

Common issues:

Window decorations are missing, or the decorations look strange

  • On some desktops (i.e. GNOME), Wayland applications use a library called libdecor to provide window decorations. If this library is not installed, the decorations will be missing. This library uses plugins to generate different decoration styles, and if a plugin to generate native-looking decorations is not installed (i.e. the GTK plugin), the decorations will not appear to be 'native'.

Windows do not appear immediately after creation

  • Wayland requires that the application initially present a buffer before the window becomes visible. Additionally, applications must have an event loop and processes messages on a regular basis, or the application can appear unresponsive to both the user and desktop compositor.

SDL_SetWindowPosition() doesn't work on non-popup windows

  • Wayland does not allow toplevel windows to position themselves programmatically.

Retrieving the global mouse cursor position when the cursor is outside a window doesn't work

  • Wayland only provides applications with the cursor position within the borders of the application windows. Querying the global position when an application window does not have mouse focus returns 0,0 as the actual cursor position is unknown. In most cases, applications don't actually need the global cursor position and should use the window-relative coordinates as provided by the mouse movement event or from SDL_GetMouseState() instead.

Warping the global mouse cursor position via SDL_WarpMouseGlobal() doesn't work

  • For security reasons, Wayland does not allow warping the global mouse cursor position.