| 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 |