DOKK / manpages / debian 13 / libsdl3-doc / SDL_SetWindowShape.3.en
SDL_SetWindowShape(3) SDL3 FUNCTIONS SDL_SetWindowShape(3)

SDL_SetWindowShape - Set the shape of a transparent window.

Defined in SDL3/SDL_video.h

#include "SDL3/SDL.h"
bool SDL_SetWindowShape(SDL_Window *window, SDL_Surface *shape);

This sets the alpha channel of a transparent window and any fully transparent areas are also transparent to mouse clicks. If you are using something besides the SDL render API, then you are responsible for drawing the alpha channel of the window to match the shape alpha channel to get consistent cross-platform results.

The shape is copied inside this function, so you can free it afterwards. If your shape surface changes, you should call

SDL_SetWindowShape () again to update the window. This is an expensive operation, so should be done sparingly.

The window must have been created with the

SDL_WINDOW_TRANSPARENT
flag.

the window.
the surface representing the shape of the window, or NULL to remove any current shape.

Returns true on success or false on failure; call

SDL_GetError () for more information.

This function should only be called on the main thread.

This function is available since SDL 3.2.0.

SDL 3.2.10 Simple Directmedia Layer