1 .TH "SDL_DisplayFormatAlpha" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 

     2 .SH "NAME"

     3 SDL_DisplayFormatAlpha \- Convert a surface to the display format

     4 .SH "SYNOPSIS"

     5 .PP

     6 \fB#include "SDL\&.h"

     7 .sp

     8 \fBSDL_Surface *\fBSDL_DisplayFormatAlpha\fP\fR(\fBSDL_Surface *surface\fR);

     9 .SH "DESCRIPTION"

    10 .PP

    11 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

    12 .PP

    13 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\&.

    14 .PP

    15 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\&.

    16 .SH "RETURN VALUE"

    17 .PP

    18 If the conversion fails or runs out of memory, it returns \fBNULL\fR

    19 .SH "SEE ALSO"

    20 .PP

    21 \fISDL_ConvertSurface\fR, \fISDL_SetAlpha\fR, \fISDL_SetColorKey\fR, \fISDL_DisplayFormat\fR, \fISDL_Surface\fR

    22 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01