SDL_DisplayFormatAlpha -- Convert a surface to the display format


#include "SDL.h"

SDL_Surface *SDL_DisplayFormatAlpha(SDL_Surface *surface);


This function takes a surface and copies it to a new surface of the pixel format and colors of the video framebuffer plus an alpha channel, suitable for fast blitting onto the display surface. It calls SDL_ConvertSurface.

If you want to take advantage of hardware colorkey or alpha blit acceleration, you should set the colorkey and alpha value before calling this function.

This function can be used to convert a colorkey to an alpha channel, if the SDL_SRCCOLORKEY flag is set on the surface. The generated surface will then be transparent (alpha=0) where the pixels match the colorkey, and opaque (alpha=255) elsewhere.

Of course, the video surface must be initialised using SDL_SetVideoMode before this function is called, or it will segfault.

Return Value

Returns a copy of surface converted to the display format. This surface must be freed using SDL_FreeSurface. If the conversion fails or runs out of memory, it returns NULL

See Also

SDL_ConvertSurface, SDL_SetAlpha, SDL_SetColorKey, SDL_DisplayFormat, SDL_Surface

SDL_DisplayFormatAlpha (last edited 2009-06-15 23:11:23 by 82-171-113-142)