(This is the documentation for SDL3, which is under heavy development and the API is changing! SDL2 is the current stable version!)

SDL_SetSurfaceColorKey

Set the color key (transparent pixel) in a surface.

Header File

Syntax

int SDL_SetSurfaceColorKey(SDL_Surface *surface, int flag, Uint32 key);

Function Parameters

surface	the SDL_Surface structure to update
flag	SDL_TRUE to enable color key, SDL_FALSE to disable color key
key	the transparent pixel

Return Value

Returns 0 on success or a negative error code on failure; call SDL_GetError() for more information.

Remarks

The color key defines a pixel value that will be treated as transparent in a blit. For example, one can use this to specify that cyan pixels should be considered transparent, and therefore not rendered.

It is a pixel of the format used by the surface, as generated by SDL_MapRGB().

RLE acceleration can substantially speed up blitting of images with large horizontal runs of transparent pixels. See SDL_SetSurfaceRLE() for details.

Version

This function is available since SDL 3.0.0.