| .TH "SDL_DisplayFormatAlpha" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" |
| .SH "NAME" |
| SDL_DisplayFormatAlpha \- Convert a surface to the display format |
| .SH "SYNOPSIS" |
| .PP |
| \fB#include "SDL\&.h" |
| .sp |
| \fBSDL_Surface *\fBSDL_DisplayFormatAlpha\fP\fR(\fBSDL_Surface *surface\fR); |
| .SH "DESCRIPTION" |
| .PP |
| 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 |
| .PP |
| 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\&. |
| .PP |
| 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\&. |
| .SH "RETURN VALUE" |
| .PP |
| If the conversion fails or runs out of memory, it returns \fBNULL\fR |
| .SH "SEE ALSO" |
| .PP |
| \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 |
