annotate docs/man3/SDL_GetRGBA.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
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e5bc29de3f0a Updated from the SDL Documentation Project
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1 .TH "SDL_GetRGBA" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference"
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2 .SH "NAME"
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3 SDL_GetRGBA \- Get RGBA values from a pixel in the specified pixel format\&.
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4 .SH "SYNOPSIS"
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5 .PP
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6 \fB#include "SDL\&.h"
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7 .sp
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8 \fBvoid \fBSDL_GetRGBA\fP\fR(\fBUint32 pixel, SDL_PixelFormat *fmt, Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a\fR);
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9 .SH "DESCRIPTION"
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10 .PP
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11 Get RGBA component values from a pixel stored in the specified pixel format\&.
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12 .PP
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13 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])\&.
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14 .PP
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15 If the surface has no alpha component, the alpha will be returned as 0xff (100% opaque)\&.
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16 .SH "SEE ALSO"
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17 .PP
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18 \fISDL_GetRGB\fR, \fISDL_MapRGB\fR, \fISDL_MapRGBA\fR, \fISDL_PixelFormat\fR
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19 .\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01