debian man page for sdl_displayformatalpha

SDL_DisplayFormatAlpha(3)					 SDL API Reference					 SDL_DisplayFormatAlpha(3)

NAME
       SDL_DisplayFormatAlpha - Convert a surface to the display format

SYNOPSIS
       #include "SDL.h"

       SDL_Surface *SDL_DisplayFormatAlpha(SDL_Surface *surface);

DESCRIPTION
       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 colourkey to an alpha channel, if the SDL_SRCCOLORKEY flag is set on the surface. The generated sur-
       face will then be transparent (alpha=0) where the pixels match the colourkey, and opaque (alpha=255) elsewhere.

RETURN VALUE
       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
							      Tue 11 Sep 2001, 23:01					 SDL_DisplayFormatAlpha(3)