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Date: Tue, 12 Aug 2003 14:26:19 +0200 (MEST) From: "Mattias Engdeg?rd" Subject: bug in SDL_GetRGB/GetRGBA There's an embarrassing bug in GetRGB/GetRGBA which apparently has been there for years. It incorrectly converts colours with < 8 bits/channel. It came to my attention today in #sdl. What it does now is (for each channel): rv = (pixel & fmt->Rmask) >> fmt->Rshift; *r = (rv << fmt->Rloss) + (rv >> (8 - fmt->Rloss)); which is wrong; the last line should be *r = (rv << fmt->Rloss) + (rv >> (8 - (fmt->Rloss << 1)));
author Sam Lantinga <slouken@libsdl.org>
date Tue, 12 Aug 2003 15:17:20 +0000
parents e5bc29de3f0a
children 546f7c1eb755
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.TH "SDL_Color" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_Color\- Format independent color description
.SH "STRUCTURE DEFINITION"
.PP
.nf
\f(CWtypedef struct{
  Uint8 r;
  Uint8 g;
  Uint8 b;
  Uint8 unused;
} SDL_Color;\fR
.fi
.PP
.SH "STRUCTURE DATA"
.TP 20
\fBr\fR
Red intensity
.TP 20
\fBg\fR
Green intensity
.TP 20
\fBb\fR
Blue intensity
.TP 20
\fBunused\fR
Unused
.SH "DESCRIPTION"
.PP
\fBSDL_Color\fR describes a color in a format independent way\&. You can convert a \fBSDL_Color\fR to a pixel value for a certain pixel format using \fI\fBSDL_MapRGB\fP\fR\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_PixelFormat\fR\fR, \fI\fBSDL_SetColors\fP\fR, \fI\fBSDL_Palette\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01