DRAFT |
SDL_SetColorKey
Use this function to set the color key (transparent pixel) in a blittable surface *???and enable or disable RLE blit acceleration???*.
Syntax
int SDL_SetColorKey(SDL_Surface* surface,
int flag,
Uint32 key)
Function Parameters
surface |
the surface / SDL_Surface to update |
flag |
non-zero to enable colorkey, 0 to disable colorkey; see [[#Remarks|Remarks]] for details |
key |
the transparent pixel in the native surface format |
Return Value
Returns 0 on success, or -1 if the surface is not valid; call SDL_GetError() for more information.
Code Examples
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Remarks
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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.
There are several instances of surface here where it is unclear whether it should be bolded as the param.
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 drawn 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. SDL_DisplayFormat is not in 1.3.
If flag is 0, this function clears any current color key.
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