view docs/man3/SDL_SetColorKey.3 @ 4388:1524d3237820 SDL-1.2

Fixed bug #896 John Popplewell 2009-12-08 23:05:50 PST Originally reported by AKFoerster on the mailing list. Error decoding UTF8 Russian text to UTF-16LE on Windows, but specifically on platforms without iconv support (the default on Windows). Valid UTF8 characters are flagged as being overlong and then substituted by the UNKNOWN_UNICODE character. After studying the testiconv.c example program, reading the RFCs and putting some printf statements in SDL_iconv.c the problem is in a test for 'Maximum overlong sequences', specifically 4.2.1, which is carried out by the following code: } else if ( p[0] >= 0xC0 ) { if ( (p[0] & 0xE0) != 0xC0 ) { /* Skip illegal sequences return SDL_ICONV_EILSEQ; */ ch = UNKNOWN_UNICODE; } else { if ( (p[0] & 0xCE) == 0xC0 ) { <<<<<<<< here overlong = SDL_TRUE; } ch = (Uint32)(p[0] & 0x1F); left = 1; } } else { Here is the 2-byte encoding of a character in range 00000080 - 000007FF 110xxxxx 10xxxxxx The line in question is supposed to be checking for an overlong sequence which would be less than 11000001 10111111 which should be represented as a single byte. BUT, the mask value (0xCE) is wrong, it isn't checking the top-most bit: 11000001 value 11001110 mask (incorrect) ^ and should be (0xDE): 11000001 value 11011110 mask (correct) making the above code: } else if ( p[0] >= 0xC0 ) { if ( (p[0] & 0xE0) != 0xC0 ) { /* Skip illegal sequences return SDL_ICONV_EILSEQ; */ ch = UNKNOWN_UNICODE; } else { if ( (p[0] & 0xDE) == 0xC0 ) { <<<<<<<< here overlong = SDL_TRUE; } ch = (Uint32)(p[0] & 0x1F); left = 1; } } else { I can supply a test program and/or a patch if required, best regards, John Popplewell
author Sam Lantinga <slouken@libsdl.org>
date Fri, 11 Dec 2009 08:00:57 +0000
parents 1238da4a7112
children
line wrap: on
line source

.TH "SDL_SetColorKey" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_SetColorKey \- Sets the color key (transparent pixel) in a blittable surface and RLE acceleration\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_SetColorKey\fP\fR(\fBSDL_Surface *surface, Uint32 flag, Uint32 key\fR);
.SH "DESCRIPTION"
.PP
 Sets the color key (transparent pixel) in a blittable surface and enables or disables RLE blit acceleration\&.
.PP
RLE acceleration can substantially speed up blitting of images with large horizontal runs of transparent pixels (i\&.e\&., pixels that match the \fBkey\fR value)\&. The \fBkey\fR must be of the same pixel format as the \fBsurface\fR, \fI\fBSDL_MapRGB\fP\fR is often useful for obtaining an acceptable value\&.
.PP
If \fBflag\fR is \fBSDL_SRCCOLORKEY\fP then \fBkey\fR is the transparent pixel value in the source image of a blit\&.
.PP
If \fBflag\fR is OR\&'d with \fBSDL_RLEACCEL\fP then the surface will be draw using RLE acceleration when drawn with \fISDL_BlitSurface\fR\&. The surface will actually be encoded for RLE acceleration the first time \fISDL_BlitSurface\fR or \fISDL_DisplayFormat\fR is called on the surface\&.
.PP
If \fBflag\fR is 0, this function clears any current color key\&.
.SH "RETURN VALUE"
.PP
This function returns \fB0\fR, or \fB-1\fR if there was an error\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_BlitSurface\fP\fR, \fI\fBSDL_DisplayFormat\fP\fR, \fI\fBSDL_MapRGB\fP\fR, \fI\fBSDL_SetAlpha\fP\fR
.\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01