docs/man3/SDL_DisplayFormatAlpha.3
author Aaron Wishnick <schnarf@gmail.com>
Wed, 18 Jun 2008 04:51:10 +0000
branchgsoc2008_audio_resampling
changeset 2655 b8e736c8a5a8
parent 2283 546f7c1eb755
child 4311 1238da4a7112
permissions -rw-r--r--
Added beginnings of resampling code.
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.TH "SDL_DisplayFormatAlpha" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
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.SH "NAME"
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SDL_DisplayFormatAlpha \- Convert a surface to the display format
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.SH "SYNOPSIS"
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.PP
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\fB#include "SDL\&.h"
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.sp
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\fBSDL_Surface *\fBSDL_DisplayFormatAlpha\fP\fR(\fBSDL_Surface *surface\fR);
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.SH "DESCRIPTION"
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.PP
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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
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.PP
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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\&.
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.PP
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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\&.
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.SH "RETURN VALUE"
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.PP
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If the conversion fails or runs out of memory, it returns \fBNULL\fR
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.SH "SEE ALSO"
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.PP
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\fISDL_ConvertSurface\fR, \fISDL_SetAlpha\fR, \fISDL_SetColorKey\fR, \fISDL_DisplayFormat\fR, \fISDL_Surface\fR
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...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01