NAME¶
SDL_SetColorKey - Sets the color key (transparent pixel) in a blittable surface
and RLE acceleration.
SYNOPSIS¶
#include "SDL.h"
int SDL_SetColorKey(
SDL_Surface *surface, Uint32 flag,
Uint32 key);
DESCRIPTION¶
Sets the color key (transparent pixel) in a blittable surface and enables or
disables RLE blit acceleration.
RLE acceleration can substantially speed up blitting of images with large
horizontal runs of transparent pixels (i.e., pixels that match the
key
value). The
key must be of the same pixel format as the
surface,
SDL_MapRGB is often useful for obtaining an acceptable
value.
If
flag is
SDL_SRCCOLORKEY then
key is the transparent
pixel value in the source image of a blit.
If
flag is OR'd with
SDL_RLEACCEL then the surface will be draw
using RLE acceleration when drawn with
SDL_BlitSurface. The surface
will actually be encoded for RLE acceleration the first time
SDL_BlitSurface or
SDL_DisplayFormat is called on the surface.
If
flag is 0, this function clears any current color key.
RETURN VALUE¶
This function returns
0, or
-1 if there was an error.
SEE ALSO¶
SDL_BlitSurface,
SDL_DisplayFormat,
SDL_MapRGB,
SDL_SetAlpha