view docs/man3/SDL_GetRGBA.3 @ 4207:a673f44949d6 SDL-1.2

Fixed bug #562 this patch by Diego Pettenò <flameeyes@gentoo.org> for SDL-1.2: The attached patch applies over latest ~arch SDL version, and allows to use the xinerama support to launch an application full screened on the head "0". The SDL_VIDEO_FULLSCREEN_HEAD environment variable sets the head on which the full screen will be displayed, but if you set it to 0, the code simply ignores it as unset. My patch changes the unset value to -1, so that the 0 value can be used correctly. Without this, trying to get fullscreen on head 0 would get the same result than not having xinerama enabled at all. http://sources.gentoo.org/media-libs/libsdl/files/libsdl-1.2.11-xinerama-head-0.patch SDL-1.3 doesnt seem to have any code like this, but it's still good for SDL-1.2
author Sam Lantinga <slouken@libsdl.org>
date Mon, 21 Sep 2009 07:20:51 +0000
parents 4e3b250c950e
children 1238da4a7112
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.TH "SDL_GetRGBA" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_GetRGBA \- Get RGBA values from a pixel in the specified pixel format\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBvoid \fBSDL_GetRGBA\fP\fR(\fBUint32 pixel, SDL_PixelFormat *fmt, Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a\fR);
.SH "DESCRIPTION"
.PP
Get RGBA component values from a pixel stored in the specified pixel format\&.
.PP
This function uses the entire 8-bit [0\&.\&.255] range when converting color components from pixel formats with less than 8-bits per RGB component (e\&.g\&., a completely white pixel in 16-bit RGB565 format would return [0xff, 0xff, 0xff] not [0xf8, 0xfc, 0xf8])\&.
.PP
If the surface has no alpha component, the alpha will be returned as 0xff (100% opaque)\&.
.SH "SEE ALSO"
.PP
\fISDL_GetRGB\fR, \fISDL_MapRGB\fR, \fISDL_MapRGBA\fR, \fISDL_PixelFormat\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01