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[devel] Fix and clarify LEGACY 16-to-8 scaling.

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John Bowler 2011-06-13 20:50:42 -05:00 committed by Glenn Randers-Pehrson
parent 97039baa88
commit 74945f2f04
2 changed files with 7 additions and 7 deletions
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10
pngrtran.c
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@ -1,7 +1,7 @@
/* pngrtran.c - transforms the data in a row for PNG readers /* pngrtran.c - transforms the data in a row for PNG readers
* *
* Last changed in libpng 1.5.3 [(PENDING RELEASE)] * Last changed in libpng 1.5.4 [(PENDING RELEASE)]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson * Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@ -2499,17 +2499,17 @@ png_do_chop(png_row_infop row_info, png_bytep row)
* (V * 255 + 32895) >> 16 * (V * 255 + 32895) >> 16
*/ */
#ifdef PNG_LEGACY_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
*dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0);
#else
png_int_32 tmp = *sp++; /* must be signed! */ png_int_32 tmp = *sp++; /* must be signed! */
#ifdef PNG_LEGACY_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
tmp += (((int)*sp++ - tmp) > 128) ? 1 : 0;
#else
# ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED # ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24; tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24;
# else # else
sp++; sp++;
# endif # endif
*dp++ = (png_byte)tmp;
#endif #endif
*dp++ = (png_byte)tmp;
} }
row_info->bit_depth = 8; row_info->bit_depth = 8;

4
pngtest.c
View File

@ -1,7 +1,7 @@
/* pngtest.c - a simple test program to test libpng /* pngtest.c - a simple test program to test libpng
* *
* Last changed in libpng 1.5.3 [(PENDING RELEASE)] * Last changed in libpng 1.5.4 [(PENDING RELEASE)]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson * Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@ -1794,4 +1794,4 @@ main(int argc, char *argv[])
} }
/* Generate a compiler error if there is an old png.h in the search path. */ /* Generate a compiler error if there is an old png.h in the search path. */
typedef png_libpng_version_1_5_4beta01 Your_png_h_is_not_version_1_5_4beta01; typedef png_libpng_version_1_5_4beta02 Your_png_h_is_not_version_1_5_4beta02;