view docs/man3/SDL_FillRect.3 @ 688:c0522010bb6d

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
line wrap: on
line source

.TH "SDL_FillRect" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_FillRect\- This function performs a fast fill of the given rectangle with some color
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_FillRect\fP\fR(\fBSDL_Surface *dst, SDL_Rect *dstrect, Uint32 color\fR);
.SH "DESCRIPTION"
.PP
This function performs a fast fill of the given rectangle with \fBcolor\fR\&. If \fBdstrect\fR is \fBNULL\fP, the whole surface will be filled with \fBcolor\fR\&.
.PP
The color should be a pixel of the format used by the surface, and can be generated by the \fISDL_MapRGB\fR or \fISDL_MapRGBA\fR functions\&. If the color value contains an alpha value then the destination is simply "filled" with that alpha information, no blending takes place\&.
.PP
If there is a clip rectangle set on the destination (set via \fISDL_SetClipRect\fR) then this function will clip based on the intersection of the clip rectangle and the \fBdstrect\fR rectangle and the dstrect rectangle will be modified to represent the area actually filled\&.
.SH "RETURN VALUE"
.PP
This function returns \fB0\fR on success, or \fB-1\fR on error\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_MapRGB\fP\fR, \fI\fBSDL_MapRGBA\fP\fR, \fI\fBSDL_BlitSurface\fP\fR, \fI\fBSDL_Rect\fR\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01