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[devel] Re-initialize the zlib compressor before compressing non-IDAT chunks.

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Glenn Randers-Pehrson
2011-03-31 20:14:29 -05:00
parent dcc3505c7b
commit 6b3d50b2cd
9 changed files with 239 additions and 91 deletions
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82
pngwrite.c
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@@ -1,7 +1,7 @@
/* pngwrite.c - general routines to write a PNG file
*
* Last changed in libpng 1.5.1 [February 3, 2011]
* Last changed in libpng 1.5.3 [(PENDING RELEASE)]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -1491,6 +1491,86 @@ png_set_compression_method(png_structp png_ptr, int method)
png_ptr->zlib_method = method;
}
/* The following were added to libpng-1.5.2 */
#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION
void PNGAPI
png_set_text_compression_level(png_structp png_ptr, int level)
{
png_debug(1, "in png_set_text_compression_level");
if (png_ptr == NULL)
return;
png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_LEVEL;
png_ptr->zlib_text_level = level;
}
void PNGAPI
png_set_text_compression_mem_level(png_structp png_ptr, int mem_level)
{
png_debug(1, "in png_set_text_compression_mem_level");
if (png_ptr == NULL)
return;
png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL;
png_ptr->zlib_text_mem_level = mem_level;
}
void PNGAPI
png_set_text_compression_strategy(png_structp png_ptr, int strategy)
{
png_debug(1, "in png_set_text_compression_strategy");
if (png_ptr == NULL)
return;
png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_STRATEGY;
png_ptr->zlib_text_strategy = strategy;
}
void PNGAPI
png_set_text_compression_window_bits(png_structp png_ptr, int window_bits)
{
if (png_ptr == NULL)
return;
if (window_bits > 15)
png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
else if (window_bits < 8)
png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
#ifndef WBITS_8_OK
/* Avoid libpng bug with 256-byte windows */
if (window_bits == 8)
{
png_warning(png_ptr, "Text compression window is being reset to 512");
window_bits = 9;
}
#endif
png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS;
png_ptr->zlib_text_window_bits = window_bits;
}
void PNGAPI
png_set_text_compression_method(png_structp png_ptr, int method)
{
png_debug(1, "in png_set_text_compression_method");
if (png_ptr == NULL)
return;
if (method != 8)
png_warning(png_ptr, "Only compression method 8 is supported by PNG");
png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_METHOD;
png_ptr->zlib_text_method = method;
}
#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
/* end of API added to libpng-1.5.2 */
void PNGAPI
png_set_write_status_fn(png_structp png_ptr, png_write_status_ptr write_row_fn)
{