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.TH "SDL_DisplayFormatAlpha" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference"
SDL_DisplayFormatAlpha \- Convert a surface to the display format
\fB#include "SDL\&.h"
\fBSDL_Surface *\fBSDL_DisplayFormatAlpha\fP\fR(\fBSDL_Surface *surface\fR);
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 \fISDL_ConvertSurface\fR
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 \fBSDL_SRCCOLORKEY\fP flag is set on the surface\&. The generated surface will then be transparent (alpha=0) where the pixels match the colourkey, and opaque (alpha=255) elsewhere\&.
If the conversion fails or runs out of memory, it returns \fBNULL\fR
\fISDL_ConvertSurface\fR, \fISDL_SetAlpha\fR, \fISDL_SetColorKey\fR, \fISDL_DisplayFormat\fR, \fISDL_Surface\fR
.\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01