1155 lines
32 KiB
C
1155 lines
32 KiB
C
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/* pngwutil.c - utilities to write a png file
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libpng 1.0 beta 2 - version 0.88
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For conditions of distribution and use, see copyright notice in png.h
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Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
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January 25, 1996
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*/
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#define PNG_INTERNAL
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#include "png.h"
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/* place a 32 bit number into a buffer in png byte order. We work
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with unsigned numbers for convenience, you may have to cast
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signed numbers (if you use any, most png data is unsigned). */
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void
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png_save_uint_32(png_bytep buf, png_uint_32 i)
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{
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buf[0] = (png_byte)((i >> 24) & 0xff);
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buf[1] = (png_byte)((i >> 16) & 0xff);
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buf[2] = (png_byte)((i >> 8) & 0xff);
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buf[3] = (png_byte)(i & 0xff);
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}
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/* place a 16 bit number into a buffer in png byte order */
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void
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png_save_uint_16(png_bytep buf, png_uint_16 i)
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{
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buf[0] = (png_byte)((i >> 8) & 0xff);
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buf[1] = (png_byte)(i & 0xff);
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}
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/* write a 32 bit number */
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void
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png_write_uint_32(png_structp png_ptr, png_uint_32 i)
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{
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png_byte buf[4];
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buf[0] = (png_byte)((i >> 24) & 0xff);
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buf[1] = (png_byte)((i >> 16) & 0xff);
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buf[2] = (png_byte)((i >> 8) & 0xff);
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buf[3] = (png_byte)(i & 0xff);
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png_write_data(png_ptr, buf, 4);
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}
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/* write a 16 bit number */
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void
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png_write_uint_16(png_structp png_ptr, png_uint_16 i)
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{
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png_byte buf[2];
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buf[0] = (png_byte)((i >> 8) & 0xff);
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buf[1] = (png_byte)(i & 0xff);
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png_write_data(png_ptr, buf, 2);
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}
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/* Write a png chunk all at once. The type is an array of ASCII characters
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representing the chunk name. The array must be at least 4 bytes in
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length, and does not need to be null terminated. To be safe, pass the
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pre-defined chunk names here, and if you need a new one, define it
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where the others are defined. The length is the length of the data.
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All the data must be present. If that is not possible, use the
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png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
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functions instead. */
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void
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png_write_chunk(png_structp png_ptr, png_bytep type,
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png_bytep data, png_uint_32 length)
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{
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/* write length */
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png_write_uint_32(png_ptr, length);
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/* write chunk name */
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png_write_data(png_ptr, type, (png_uint_32)4);
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/* reset the crc and run the chunk name over it */
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png_reset_crc(png_ptr);
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png_calculate_crc(png_ptr, type, (png_uint_32)4);
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/* write the data and update the crc */
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if (length)
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{
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png_calculate_crc(png_ptr, data, length);
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png_write_data(png_ptr, data, length);
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}
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/* write the crc */
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png_write_uint_32(png_ptr, ~png_ptr->crc);
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}
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/* Write the start of a png chunk. The type is the chunk type.
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The total_length is the sum of the lengths of all the data you will be
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passing in png_write_chunk_data() */
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void
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png_write_chunk_start(png_structp png_ptr, png_bytep type,
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png_uint_32 total_length)
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{
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/* write the length */
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png_write_uint_32(png_ptr, total_length);
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/* write the chunk name */
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png_write_data(png_ptr, type, (png_uint_32)4);
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/* reset the crc and run it over the chunk name */
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png_reset_crc(png_ptr);
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png_calculate_crc(png_ptr, type, (png_uint_32)4);
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}
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/* write the data of a png chunk started with png_write_chunk_start().
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Note that multiple calls to this function are allowed, and that the
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sum of the lengths from these calls *must* add up to the total_length
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given to png_write_chunk_start() */
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void
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png_write_chunk_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
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{
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/* write the data, and run the crc over it */
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if (length)
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{
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png_calculate_crc(png_ptr, data, length);
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png_write_data(png_ptr, data, length);
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}
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}
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/* finish a chunk started with png_write_chunk_start() */
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void
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png_write_chunk_end(png_structp png_ptr)
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{
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/* write the crc */
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png_write_uint_32(png_ptr, ~png_ptr->crc);
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}
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/* simple function to write the signature */
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void
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png_write_sig(png_structp png_ptr)
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{
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/* write the 8 byte signature */
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png_write_data(png_ptr, png_sig, (png_uint_32)8);
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}
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/* Write the IHDR chunk, and update the png_struct with the necessary
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information. Note that the rest of this code depends upon this
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information being correct. */
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void
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png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
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int bit_depth, int color_type, int compression_type, int filter_type,
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int interlace_type)
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{
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png_byte buf[13]; /* buffer to store the IHDR info */
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/* pack the header information into the buffer */
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png_save_uint_32(buf, width);
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png_save_uint_32(buf + 4, height);
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buf[8] = (png_byte)bit_depth;
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buf[9] = (png_byte)color_type;
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buf[10] = (png_byte)compression_type;
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buf[11] = (png_byte)filter_type;
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buf[12] = (png_byte)interlace_type;
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/* save off the relevent information */
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png_ptr->bit_depth = (png_byte)bit_depth;
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png_ptr->color_type = (png_byte)color_type;
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png_ptr->interlaced = (png_byte)interlace_type;
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png_ptr->width = width;
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png_ptr->height = height;
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switch (color_type)
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{
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case 0:
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case 3:
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png_ptr->channels = 1;
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break;
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case 2:
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png_ptr->channels = 3;
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break;
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case 4:
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png_ptr->channels = 2;
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break;
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case 6:
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png_ptr->channels = 4;
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break;
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}
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png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
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png_ptr->rowbytes = ((width * (png_uint_32)png_ptr->pixel_depth + 7) >> 3);
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/* set the usr info, so any transformations can modify it */
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png_ptr->usr_width = png_ptr->width;
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png_ptr->usr_bit_depth = png_ptr->bit_depth;
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png_ptr->usr_channels = png_ptr->channels;
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/* write the chunk */
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png_write_chunk(png_ptr, png_IHDR, buf, (png_uint_32)13);
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/* initialize zlib with png info */
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png_ptr->zstream = (z_stream *)png_malloc(png_ptr, sizeof (z_stream));
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png_ptr->zstream->zalloc = png_zalloc;
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png_ptr->zstream->zfree = png_zfree;
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png_ptr->zstream->opaque = (voidpf)png_ptr;
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if (!png_ptr->do_custom_filter)
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{
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if (png_ptr->color_type == 3 || png_ptr->bit_depth < 8)
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png_ptr->do_filter = 0;
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else
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png_ptr->do_filter = 1;
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}
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if (!png_ptr->zlib_custom_strategy)
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{
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if (png_ptr->do_filter)
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png_ptr->zlib_strategy = Z_FILTERED;
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else
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png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;
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}
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if (!png_ptr->zlib_custom_level)
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png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;
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if (!png_ptr->zlib_custom_mem_level)
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png_ptr->zlib_mem_level = 8;
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if (!png_ptr->zlib_custom_window_bits)
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png_ptr->zlib_window_bits = 15;
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if (!png_ptr->zlib_custom_method)
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png_ptr->zlib_method = 8;
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deflateInit2(png_ptr->zstream, png_ptr->zlib_level,
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png_ptr->zlib_method,
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png_ptr->zlib_window_bits,
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png_ptr->zlib_mem_level,
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png_ptr->zlib_strategy);
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png_ptr->zstream->next_out = png_ptr->zbuf;
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png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
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}
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/* write the palette. We are careful not to trust png_color to be in the
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correct order for PNG, so people can redefine it to any convient
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structure. */
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void
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png_write_PLTE(png_structp png_ptr, png_colorp palette, int number)
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{
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int i;
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png_colorp pal_ptr;
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png_byte buf[3];
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png_write_chunk_start(png_ptr, png_PLTE, number * 3);
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for (i = 0, pal_ptr = palette;
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i < number;
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i++, pal_ptr++)
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{
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buf[0] = pal_ptr->red;
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buf[1] = pal_ptr->green;
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buf[2] = pal_ptr->blue;
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png_write_chunk_data(png_ptr, buf, (png_uint_32)3);
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}
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png_write_chunk_end(png_ptr);
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}
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/* write an IDAT chunk */
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void
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png_write_IDAT(png_structp png_ptr, png_bytep data, png_uint_32 length)
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{
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png_write_chunk(png_ptr, png_IDAT, data, length);
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}
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/* write an IEND chunk */
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void
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png_write_IEND(png_structp png_ptr)
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{
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png_write_chunk(png_ptr, png_IEND, NULL, (png_uint_32)0);
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}
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#if defined(PNG_WRITE_gAMA_SUPPORTED)
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/* write a gAMA chunk */
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void
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png_write_gAMA(png_structp png_ptr, double gamma)
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{
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png_uint_32 igamma;
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png_byte buf[4];
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/* gamma is saved in 1/100,000ths */
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igamma = (png_uint_32)(gamma * 100000.0 + 0.5);
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png_save_uint_32(buf, igamma);
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png_write_chunk(png_ptr, png_gAMA, buf, (png_uint_32)4);
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}
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#endif
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#if defined(PNG_WRITE_sBIT_SUPPORTED)
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/* write the sBIT chunk */
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void
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png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
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{
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png_byte buf[4];
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int size;
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/* make sure we don't depend upon the order of PNG_COLOR_8 */
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if (color_type & PNG_COLOR_MASK_COLOR)
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{
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buf[0] = sbit->red;
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buf[1] = sbit->green;
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buf[2] = sbit->blue;
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size = 3;
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}
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else
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{
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buf[0] = sbit->gray;
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size = 1;
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}
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if (color_type & PNG_COLOR_MASK_ALPHA)
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{
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buf[size++] = sbit->alpha;
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}
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png_write_chunk(png_ptr, png_sBIT, buf, (png_uint_32)size);
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}
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#endif
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#if defined(PNG_WRITE_cHRM_SUPPORTED)
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/* write the cHRM chunk */
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void
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png_write_cHRM ( png_structp png_ptr, double white_x, double white_y,
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double red_x, double red_y, double green_x, double green_y,
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double blue_x, double blue_y)
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{
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png_uint_32 itemp;
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png_byte buf[32];
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/* each value is saved int 1/100,000ths */
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itemp = (png_uint_32)(white_x * 100000.0 + 0.5);
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png_save_uint_32(buf, itemp);
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itemp = (png_uint_32)(white_y * 100000.0 + 0.5);
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png_save_uint_32(buf + 4, itemp);
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itemp = (png_uint_32)(red_x * 100000.0 + 0.5);
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png_save_uint_32(buf + 8, itemp);
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itemp = (png_uint_32)(red_y * 100000.0 + 0.5);
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png_save_uint_32(buf + 12, itemp);
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itemp = (png_uint_32)(green_x * 100000.0 + 0.5);
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png_save_uint_32(buf + 16, itemp);
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itemp = (png_uint_32)(green_y * 100000.0 + 0.5);
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png_save_uint_32(buf + 20, itemp);
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itemp = (png_uint_32)(blue_x * 100000.0 + 0.5);
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png_save_uint_32(buf + 24, itemp);
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itemp = (png_uint_32)(blue_y * 100000.0 + 0.5);
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png_save_uint_32(buf + 28, itemp);
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png_write_chunk(png_ptr, png_cHRM, buf, (png_uint_32)32);
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}
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#endif
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#if defined(PNG_WRITE_tRNS_SUPPORTED)
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/* write the tRNS chunk */
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void
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png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
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int num_trans, int color_type)
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{
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png_byte buf[6];
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if (color_type == PNG_COLOR_TYPE_PALETTE)
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{
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/* write the chunk out as it is */
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png_write_chunk(png_ptr, png_tRNS, trans, (png_uint_32)num_trans);
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}
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else if (color_type == PNG_COLOR_TYPE_GRAY)
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{
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/* one 16 bit value */
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png_save_uint_16(buf, tran->gray);
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png_write_chunk(png_ptr, png_tRNS, buf, (png_uint_32)2);
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}
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else if (color_type == PNG_COLOR_TYPE_RGB)
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{
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/* three 16 bit values */
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png_save_uint_16(buf, tran->red);
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png_save_uint_16(buf + 2, tran->green);
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png_save_uint_16(buf + 4, tran->blue);
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png_write_chunk(png_ptr, png_tRNS, buf, (png_uint_32)6);
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}
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}
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#endif
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#if defined(PNG_WRITE_bKGD_SUPPORTED)
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/* write the background chunk */
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void
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png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
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{
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png_byte buf[6];
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if (color_type == PNG_COLOR_TYPE_PALETTE)
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{
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buf[0] = back->index;
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png_write_chunk(png_ptr, png_bKGD, buf, (png_uint_32)1);
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}
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else if (color_type & PNG_COLOR_MASK_COLOR)
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{
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png_save_uint_16(buf, back->red);
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png_save_uint_16(buf + 2, back->green);
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png_save_uint_16(buf + 4, back->blue);
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png_write_chunk(png_ptr, png_bKGD, buf, (png_uint_32)6);
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}
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else
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{
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png_save_uint_16(buf, back->gray);
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png_write_chunk(png_ptr, png_bKGD, buf, (png_uint_32)2);
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}
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}
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#endif
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#if defined(PNG_WRITE_hIST_SUPPORTED)
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/* write the histogram */
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void
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png_write_hIST(png_structp png_ptr, png_uint_16p hist, int number)
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{
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int i;
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png_byte buf[3];
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png_write_chunk_start(png_ptr, png_hIST, (png_uint_32)(number * 2));
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for (i = 0; i < number; i++)
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{
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png_save_uint_16(buf, hist[i]);
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png_write_chunk_data(png_ptr, buf, (png_uint_32)2);
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}
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png_write_chunk_end(png_ptr);
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}
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#endif
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#if defined(PNG_WRITE_tEXt_SUPPORTED)
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/* write a tEXt chunk */
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void
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png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
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png_uint_32 text_len)
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{
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int key_len;
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key_len = png_strlen(key);
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/* make sure we count the 0 after the key */
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png_write_chunk_start(png_ptr, png_tEXt,
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(png_uint_32)(key_len + text_len + 1));
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/* key has an 0 at the end. How nice */
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png_write_chunk_data(png_ptr, (png_bytep )key, (png_uint_32)(key_len + 1));
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if (text && text_len)
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png_write_chunk_data(png_ptr, (png_bytep )text, (png_uint_32)text_len);
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png_write_chunk_end(png_ptr);
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}
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#endif
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#if defined(PNG_WRITE_zTXt_SUPPORTED)
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/* write a compressed chunk */
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void
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png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
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png_uint_32 text_len, int compression)
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{
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int key_len;
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char buf[1];
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int i, ret;
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png_charpp output_ptr = NULL; /* array of pointers to output */
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int num_output_ptr = 0; /* number of output pointers used */
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int max_output_ptr = 0; /* size of output_ptr */
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key_len = png_strlen(key);
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/* we can't write the chunk until we find out how much data we have,
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which means we need to run the compresser first, and save the
|
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output. This shouldn't be a problem, as the vast majority of
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comments should be reasonable, but we will set up an array of
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malloced pointers to be sure. */
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/* set up the compression buffers */
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png_ptr->zstream->avail_in = (uInt)text_len;
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png_ptr->zstream->next_in = (Bytef *)text;
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png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
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png_ptr->zstream->next_out = (Bytef *)png_ptr->zbuf;
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/* this is the same compression loop as in png_write_row() */
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do
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{
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/* compress the data */
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ret = deflate(png_ptr->zstream, Z_NO_FLUSH);
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if (ret != Z_OK)
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{
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/* error */
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if (png_ptr->zstream->msg)
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|
png_error(png_ptr, png_ptr->zstream->msg);
|
|
else
|
|
png_error(png_ptr, "zlib error");
|
|
}
|
|
/* check to see if we need more room */
|
|
if (!png_ptr->zstream->avail_out && png_ptr->zstream->avail_in)
|
|
{
|
|
/* make sure the output array has room */
|
|
if (num_output_ptr >= max_output_ptr)
|
|
{
|
|
png_uint_32 old_max;
|
|
|
|
old_max = max_output_ptr;
|
|
max_output_ptr = num_output_ptr + 4;
|
|
if (output_ptr)
|
|
{
|
|
png_charpp old_ptr;
|
|
|
|
old_ptr = output_ptr;
|
|
output_ptr = (png_charpp)png_large_malloc(png_ptr,
|
|
max_output_ptr * sizeof (png_charpp));
|
|
png_memcpy(output_ptr, old_ptr,
|
|
(png_size_t)(old_max * sizeof (png_charp)));
|
|
png_large_free(png_ptr, old_ptr);
|
|
}
|
|
else
|
|
output_ptr = (png_charpp)png_large_malloc(png_ptr,
|
|
max_output_ptr * sizeof (png_charp));
|
|
}
|
|
|
|
/* save the data */
|
|
output_ptr[num_output_ptr] = png_large_malloc(png_ptr,
|
|
png_ptr->zbuf_size);
|
|
png_memcpy(output_ptr[num_output_ptr], png_ptr->zbuf,
|
|
(png_size_t)png_ptr->zbuf_size);
|
|
num_output_ptr++;
|
|
|
|
/* and reset the buffer */
|
|
png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
|
|
png_ptr->zstream->next_out = png_ptr->zbuf;
|
|
}
|
|
/* continue until we don't have anymore to compress */
|
|
} while (png_ptr->zstream->avail_in);
|
|
|
|
/* finish the compression */
|
|
do
|
|
{
|
|
/* tell zlib we are finished */
|
|
ret = deflate(png_ptr->zstream, Z_FINISH);
|
|
if (ret != Z_OK && ret != Z_STREAM_END)
|
|
{
|
|
/* we got an error */
|
|
if (png_ptr->zstream->msg)
|
|
png_error(png_ptr, png_ptr->zstream->msg);
|
|
else
|
|
png_error(png_ptr, "zlib error");
|
|
}
|
|
|
|
/* check to see if we need more room */
|
|
if (!png_ptr->zstream->avail_out && ret == Z_OK)
|
|
{
|
|
/* check to make sure our output array has room */
|
|
if (num_output_ptr >= max_output_ptr)
|
|
{
|
|
png_uint_32 old_max;
|
|
|
|
old_max = max_output_ptr;
|
|
max_output_ptr = num_output_ptr + 4;
|
|
if (output_ptr)
|
|
{
|
|
png_charpp old_ptr;
|
|
|
|
old_ptr = output_ptr;
|
|
output_ptr = (png_charpp)png_large_malloc(png_ptr,
|
|
max_output_ptr * sizeof (png_charpp));
|
|
png_memcpy(output_ptr, old_ptr,
|
|
(png_size_t)(old_max * sizeof (png_charp)));
|
|
png_large_free(png_ptr, old_ptr);
|
|
}
|
|
else
|
|
output_ptr = (png_charpp)png_large_malloc(png_ptr,
|
|
max_output_ptr * sizeof (png_charp));
|
|
}
|
|
|
|
/* save off the data */
|
|
output_ptr[num_output_ptr] = png_large_malloc(png_ptr,
|
|
png_ptr->zbuf_size);
|
|
png_memcpy(output_ptr[num_output_ptr], png_ptr->zbuf,
|
|
(png_size_t)png_ptr->zbuf_size);
|
|
num_output_ptr++;
|
|
|
|
/* and reset the buffer pointers */
|
|
png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
|
|
png_ptr->zstream->next_out = png_ptr->zbuf;
|
|
}
|
|
} while (ret != Z_STREAM_END);
|
|
|
|
/* text length is number of buffers plus last buffer */
|
|
text_len = png_ptr->zbuf_size * num_output_ptr;
|
|
if (png_ptr->zstream->avail_out < png_ptr->zbuf_size)
|
|
text_len += (png_uint_32)(png_ptr->zbuf_size -
|
|
png_ptr->zstream->avail_out);
|
|
|
|
/* write start of chunk */
|
|
png_write_chunk_start(png_ptr, png_zTXt,
|
|
(png_uint_32)(key_len + text_len + 2));
|
|
/* write key */
|
|
png_write_chunk_data(png_ptr, (png_bytep )key, (png_uint_32)(key_len + 1));
|
|
buf[0] = (png_byte)compression;
|
|
/* write compression */
|
|
png_write_chunk_data(png_ptr, (png_bytep )buf, (png_uint_32)1);
|
|
|
|
/* write saved output buffers, if any */
|
|
for (i = 0; i < num_output_ptr; i++)
|
|
{
|
|
png_write_chunk_data(png_ptr, (png_bytep )output_ptr[i], png_ptr->zbuf_size);
|
|
png_large_free(png_ptr, output_ptr[i]);
|
|
}
|
|
if (max_output_ptr)
|
|
png_large_free(png_ptr, output_ptr);
|
|
/* write anything left in zbuf */
|
|
if (png_ptr->zstream->avail_out < png_ptr->zbuf_size)
|
|
png_write_chunk_data(png_ptr, png_ptr->zbuf,
|
|
png_ptr->zbuf_size - png_ptr->zstream->avail_out);
|
|
/* close the chunk */
|
|
png_write_chunk_end(png_ptr);
|
|
|
|
/* reset zlib for another zTXt or the image data */
|
|
deflateReset(png_ptr->zstream);
|
|
}
|
|
#endif
|
|
|
|
#if defined(PNG_WRITE_pHYs_SUPPORTED)
|
|
/* write the pHYs chunk */
|
|
void
|
|
png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
|
|
png_uint_32 y_pixels_per_unit,
|
|
int unit_type)
|
|
{
|
|
png_byte buf[9];
|
|
|
|
png_save_uint_32(buf, x_pixels_per_unit);
|
|
png_save_uint_32(buf + 4, y_pixels_per_unit);
|
|
buf[8] = (png_byte)unit_type;
|
|
|
|
png_write_chunk(png_ptr, png_pHYs, buf, (png_uint_32)9);
|
|
}
|
|
#endif
|
|
|
|
#if defined(PNG_WRITE_oFFs_SUPPORTED)
|
|
/* write the oFFs chunk */
|
|
void
|
|
png_write_oFFs(png_structp png_ptr, png_uint_32 x_offset,
|
|
png_uint_32 y_offset,
|
|
int unit_type)
|
|
{
|
|
png_byte buf[9];
|
|
|
|
png_save_uint_32(buf, x_offset);
|
|
png_save_uint_32(buf + 4, y_offset);
|
|
buf[8] = (png_byte)unit_type;
|
|
|
|
png_write_chunk(png_ptr, png_oFFs, buf, (png_uint_32)9);
|
|
}
|
|
#endif
|
|
|
|
#if defined(PNG_WRITE_tIME_SUPPORTED)
|
|
/* write the tIME chunk. Use either png_convert_from_struct_tm()
|
|
or png_convert_from_time_t(), or fill in the structure yourself */
|
|
void
|
|
png_write_tIME(png_structp png_ptr, png_timep mod_time)
|
|
{
|
|
png_byte buf[7];
|
|
|
|
png_save_uint_16(buf, mod_time->year);
|
|
buf[2] = mod_time->month;
|
|
buf[3] = mod_time->day;
|
|
buf[4] = mod_time->hour;
|
|
buf[5] = mod_time->minute;
|
|
buf[6] = mod_time->second;
|
|
|
|
png_write_chunk(png_ptr, png_tIME, buf, (png_uint_32)7);
|
|
}
|
|
#endif
|
|
|
|
/* initializes the row writing capability of libpng */
|
|
void
|
|
png_write_start_row(png_structp png_ptr)
|
|
{
|
|
/* set up row buffer */
|
|
png_ptr->row_buf = (png_bytep )png_large_malloc(png_ptr,
|
|
(((png_uint_32)png_ptr->usr_channels *
|
|
(png_uint_32)png_ptr->usr_bit_depth *
|
|
png_ptr->width + 7) >> 3) + 1);
|
|
/* set up filtering buffers, if filtering */
|
|
if (png_ptr->do_filter)
|
|
{
|
|
png_ptr->prev_row = (png_bytep )png_large_malloc(png_ptr,
|
|
png_ptr->rowbytes + 1);
|
|
png_memset(png_ptr->prev_row, 0, (png_size_t)png_ptr->rowbytes + 1);
|
|
png_ptr->save_row = (png_bytep )png_large_malloc(png_ptr,
|
|
png_ptr->rowbytes + 1);
|
|
png_memset(png_ptr->save_row, 0, (png_size_t)png_ptr->rowbytes + 1);
|
|
}
|
|
|
|
/* if interlaced, we need to set up width and height of pass */
|
|
if (png_ptr->interlaced)
|
|
{
|
|
if (!(png_ptr->transformations & PNG_INTERLACE))
|
|
{
|
|
png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
|
|
png_pass_ystart[0]) / png_pass_yinc[0];
|
|
png_ptr->usr_width = (png_ptr->width +
|
|
png_pass_inc[0] - 1 -
|
|
png_pass_start[0]) /
|
|
png_pass_inc[0];
|
|
}
|
|
else
|
|
{
|
|
png_ptr->num_rows = png_ptr->height;
|
|
png_ptr->usr_width = png_ptr->width;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
png_ptr->num_rows = png_ptr->height;
|
|
png_ptr->usr_width = png_ptr->width;
|
|
}
|
|
png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
|
|
png_ptr->zstream->next_out = png_ptr->zbuf;
|
|
}
|
|
|
|
/* Internal use only. Called when finished processing a row of data */
|
|
void
|
|
png_write_finish_row(png_structp png_ptr)
|
|
{
|
|
int ret;
|
|
|
|
/* next row */
|
|
png_ptr->row_number++;
|
|
/* see if we are done */
|
|
if (png_ptr->row_number < png_ptr->num_rows)
|
|
return;
|
|
|
|
/* if interlaced, go to next pass */
|
|
if (png_ptr->interlaced)
|
|
{
|
|
png_ptr->row_number = 0;
|
|
if (png_ptr->transformations & PNG_INTERLACE)
|
|
{
|
|
png_ptr->pass++;
|
|
}
|
|
else
|
|
{
|
|
/* loop until we find a non-zero width or height pass */
|
|
do
|
|
{
|
|
png_ptr->pass++;
|
|
if (png_ptr->pass >= 7)
|
|
break;
|
|
png_ptr->usr_width = (png_ptr->width +
|
|
png_pass_inc[png_ptr->pass] - 1 -
|
|
png_pass_start[png_ptr->pass]) /
|
|
png_pass_inc[png_ptr->pass];
|
|
png_ptr->num_rows = (png_ptr->height +
|
|
png_pass_yinc[png_ptr->pass] - 1 -
|
|
png_pass_ystart[png_ptr->pass]) /
|
|
png_pass_yinc[png_ptr->pass];
|
|
if (png_ptr->transformations & PNG_INTERLACE)
|
|
break;
|
|
} while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
|
|
|
|
}
|
|
|
|
/* reset filter row */
|
|
if (png_ptr->prev_row)
|
|
png_memset(png_ptr->prev_row, 0, (png_size_t)png_ptr->rowbytes + 1);
|
|
/* if we have more data to get, go get it */
|
|
if (png_ptr->pass < 7)
|
|
return;
|
|
}
|
|
|
|
/* if we get here, we've just written the last row, so we need
|
|
to flush the compressor */
|
|
do
|
|
{
|
|
/* tell the compressor we are done */
|
|
ret = deflate(png_ptr->zstream, Z_FINISH);
|
|
/* check for an error */
|
|
if (ret != Z_OK && ret != Z_STREAM_END)
|
|
{
|
|
if (png_ptr->zstream->msg)
|
|
png_error(png_ptr, png_ptr->zstream->msg);
|
|
else
|
|
png_error(png_ptr, "zlib error");
|
|
}
|
|
/* check to see if we need more room */
|
|
if (!png_ptr->zstream->avail_out && ret == Z_OK)
|
|
{
|
|
png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
|
|
png_ptr->zstream->next_out = png_ptr->zbuf;
|
|
png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
|
|
}
|
|
} while (ret != Z_STREAM_END);
|
|
|
|
/* write any extra space */
|
|
if (png_ptr->zstream->avail_out < png_ptr->zbuf_size)
|
|
{
|
|
png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
|
|
png_ptr->zstream->avail_out);
|
|
}
|
|
|
|
deflateReset(png_ptr->zstream);
|
|
}
|
|
|
|
#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
|
|
/* pick out the correct pixels for the interlace pass.
|
|
|
|
The basic idea here is to go through the row with a source
|
|
pointer and a destination pointer (sp and dp), and copy the
|
|
correct pixels for the pass. As the row gets compacted,
|
|
sp will always be >= dp, so we should never overwrite anything.
|
|
See the default: case for the easiest code to understand.
|
|
*/
|
|
void
|
|
png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
|
|
{
|
|
/* we don't have to do anything on the last pass (6) */
|
|
if (row && row_info && pass < 6)
|
|
{
|
|
/* each pixel depth is handled seperately */
|
|
switch (row_info->pixel_depth)
|
|
{
|
|
case 1:
|
|
{
|
|
png_bytep sp;
|
|
png_bytep dp;
|
|
int shift;
|
|
int d;
|
|
int value;
|
|
png_uint_32 i;
|
|
|
|
dp = row;
|
|
d = 0;
|
|
shift = 7;
|
|
for (i = png_pass_start[pass];
|
|
i < row_info->width;
|
|
i += png_pass_inc[pass])
|
|
{
|
|
sp = row + (png_size_t)(i >> 3);
|
|
value = (int)(*sp >> (7 - (int)(i & 7))) & 0x1;
|
|
d |= (value << shift);
|
|
|
|
if (shift == 0)
|
|
{
|
|
shift = 7;
|
|
*dp++ = (png_byte)d;
|
|
d = 0;
|
|
}
|
|
else
|
|
shift--;
|
|
|
|
}
|
|
if (shift != 7)
|
|
*dp = (png_byte)d;
|
|
break;
|
|
}
|
|
case 2:
|
|
{
|
|
png_bytep sp;
|
|
png_bytep dp;
|
|
int shift;
|
|
int d;
|
|
int value;
|
|
png_uint_32 i;
|
|
|
|
dp = row;
|
|
shift = 6;
|
|
d = 0;
|
|
for (i = png_pass_start[pass];
|
|
i < row_info->width;
|
|
i += png_pass_inc[pass])
|
|
{
|
|
sp = row + (png_size_t)(i >> 2);
|
|
value = (*sp >> ((3 - (int)(i & 3)) << 1)) & 0x3;
|
|
d |= (value << shift);
|
|
|
|
if (shift == 0)
|
|
{
|
|
shift = 6;
|
|
*dp++ = (png_byte)d;
|
|
d = 0;
|
|
}
|
|
else
|
|
shift -= 2;
|
|
}
|
|
if (shift != 6)
|
|
*dp = (png_byte)d;
|
|
break;
|
|
}
|
|
case 4:
|
|
{
|
|
png_bytep sp;
|
|
png_bytep dp;
|
|
int shift;
|
|
int d;
|
|
int value;
|
|
png_uint_32 i;
|
|
|
|
dp = row;
|
|
shift = 4;
|
|
d = 0;
|
|
for (i = png_pass_start[pass];
|
|
i < row_info->width;
|
|
i += png_pass_inc[pass])
|
|
{
|
|
sp = row + (png_size_t)(i >> 1);
|
|
value = (*sp >> ((1 - (int)(i & 1)) << 2)) & 0xf;
|
|
d |= (value << shift);
|
|
|
|
if (shift == 0)
|
|
{
|
|
shift = 4;
|
|
*dp++ = (png_byte)d;
|
|
d = 0;
|
|
}
|
|
else
|
|
shift -= 4;
|
|
}
|
|
if (shift != 4)
|
|
*dp = (png_byte)d;
|
|
break;
|
|
}
|
|
default:
|
|
{
|
|
png_bytep sp;
|
|
png_bytep dp;
|
|
png_uint_32 i;
|
|
int pixel_bytes;
|
|
|
|
/* start at the beginning */
|
|
dp = row;
|
|
/* find out how many bytes each pixel takes up */
|
|
pixel_bytes = (row_info->pixel_depth >> 3);
|
|
/* loop through the row, only looking at the pixels that
|
|
matter */
|
|
for (i = png_pass_start[pass];
|
|
i < row_info->width;
|
|
i += png_pass_inc[pass])
|
|
{
|
|
/* find out where the original pixel is */
|
|
sp = row + (png_size_t)(i * pixel_bytes);
|
|
/* move the pixel */
|
|
if (dp != sp)
|
|
png_memcpy(dp, sp, pixel_bytes);
|
|
/* next pixel */
|
|
dp += pixel_bytes;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
/* set new row width */
|
|
row_info->width = (row_info->width +
|
|
png_pass_inc[pass] - 1 -
|
|
png_pass_start[pass]) /
|
|
png_pass_inc[pass];
|
|
row_info->rowbytes = ((row_info->width *
|
|
row_info->pixel_depth + 7) >> 3);
|
|
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* this filters the row. Both row and prev_row have space at the
|
|
first byte for the filter byte. */
|
|
void
|
|
png_write_filter_row(png_row_infop row_info, png_bytep row,
|
|
png_bytep prev_row)
|
|
{
|
|
int minf, bpp;
|
|
png_uint_32 i, v;
|
|
png_uint_32 s0, s1, s2, s3, s4, mins;
|
|
png_bytep rp, pp, cp, lp;
|
|
|
|
/* find out how many bytes offset each pixel is */
|
|
bpp = (row_info->pixel_depth + 7) / 8;
|
|
if (bpp < 1)
|
|
bpp = 1;
|
|
|
|
/* the prediction method we use is to find which method provides
|
|
the smallest value when summing the abs of the distances from
|
|
zero using anything >= 128 as negitive numbers. */
|
|
s0 = s1 = s2 = s3 = s4 = 0;
|
|
|
|
for (i = 0, rp = row + 1, pp = prev_row + 1, lp = row + 1 - bpp,
|
|
cp = prev_row + 1 - bpp;
|
|
i < bpp; i++, rp++, pp++, lp++, cp++)
|
|
{
|
|
/* check none filter */
|
|
v = *rp;
|
|
if (v < 128)
|
|
s0 += v;
|
|
else
|
|
s0 += 256 - v;
|
|
|
|
/* check up filter */
|
|
v = (png_byte)(((int)*rp - (int)*pp) & 0xff);
|
|
|
|
if (v < 128)
|
|
s2 += v;
|
|
else
|
|
s2 += 256 - v;
|
|
|
|
/* check avg filter */
|
|
v = (png_byte)(((int)*rp - ((int)*pp / 2)) & 0xff);
|
|
|
|
if (v < 128)
|
|
s3 += v;
|
|
else
|
|
s3 += 256 - v;
|
|
}
|
|
|
|
/* some filters are same until we get past bpp */
|
|
s1 = s0;
|
|
s4 = s2;
|
|
|
|
for (; i < row_info->rowbytes; i++, rp++, pp++, lp++, cp++)
|
|
{
|
|
int a, b, c, pa, pb, pc, p;
|
|
|
|
/* check none filter */
|
|
v = *rp;
|
|
if (v < 128)
|
|
s0 += v;
|
|
else
|
|
s0 += 256 - v;
|
|
|
|
/* check sub filter */
|
|
v = (png_byte)(((int)*rp - (int)*lp) & 0xff);
|
|
|
|
if (v < 128)
|
|
s1 += v;
|
|
else
|
|
s1 += 256 - v;
|
|
|
|
/* check up filter */
|
|
v = (png_byte)(((int)*rp - (int)*pp) & 0xff);
|
|
|
|
if (v < 128)
|
|
s2 += v;
|
|
else
|
|
s2 += 256 - v;
|
|
|
|
/* check avg filter */
|
|
v = (png_byte)(((int)*rp - (((int)*pp + (int)*lp) / 2)) & 0xff);
|
|
|
|
if (v < 128)
|
|
s3 += v;
|
|
else
|
|
s3 += 256 - v;
|
|
|
|
/* check paeth filter */
|
|
b = *pp;
|
|
c = *cp;
|
|
a = *lp;
|
|
p = a + b - c;
|
|
pa = abs(p - a);
|
|
pb = abs(p - b);
|
|
pc = abs(p - c);
|
|
|
|
if (pa <= pb && pa <= pc)
|
|
p = a;
|
|
else if (pb <= pc)
|
|
p = b;
|
|
else
|
|
p = c;
|
|
|
|
v = (png_byte)(((int)*rp - p) & 0xff);
|
|
|
|
if (v < 128)
|
|
s4 += v;
|
|
else
|
|
s4 += 256 - v;
|
|
}
|
|
|
|
mins = s0;
|
|
minf = 0;
|
|
|
|
if (s1 < mins)
|
|
{
|
|
mins = s1;
|
|
minf = 1;
|
|
}
|
|
|
|
if (s2 < mins)
|
|
{
|
|
mins = s2;
|
|
minf = 2;
|
|
}
|
|
|
|
if (s3 < mins)
|
|
{
|
|
mins = s3;
|
|
minf = 3;
|
|
}
|
|
|
|
if (s4 < mins)
|
|
{
|
|
minf = 4;
|
|
}
|
|
|
|
/* set filter byte */
|
|
row[0] = (png_byte)minf;
|
|
|
|
/* do filter */
|
|
switch (minf)
|
|
{
|
|
/* sub filter */
|
|
case 1:
|
|
for (i = bpp, rp = row + (png_size_t)row_info->rowbytes,
|
|
lp = row + (png_size_t)row_info->rowbytes - bpp;
|
|
i < row_info->rowbytes; i++, rp--, lp--)
|
|
{
|
|
*rp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
|
|
}
|
|
break;
|
|
/* up filter */
|
|
case 2:
|
|
for (i = 0, rp = row + (png_size_t)row_info->rowbytes,
|
|
pp = prev_row + (png_size_t)row_info->rowbytes;
|
|
i < row_info->rowbytes; i++, rp--, pp--)
|
|
{
|
|
*rp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
|
|
}
|
|
break;
|
|
/* avg filter */
|
|
case 3:
|
|
for (i = row_info->rowbytes,
|
|
rp = row + (png_size_t)row_info->rowbytes,
|
|
pp = prev_row + (png_size_t)row_info->rowbytes,
|
|
lp = row + (png_size_t)row_info->rowbytes - bpp;
|
|
i > bpp; i--, rp--, lp--, pp--)
|
|
{
|
|
*rp = (png_byte)(((int)*rp - (((int)*lp + (int)*pp) /
|
|
2)) & 0xff);
|
|
}
|
|
for (; i > 0; i--, rp--, pp--)
|
|
{
|
|
*rp = (png_byte)(((int)*rp - ((int)*pp / 2)) & 0xff);
|
|
}
|
|
break;
|
|
/* paeth filter */
|
|
case 4:
|
|
for (i = row_info->rowbytes,
|
|
rp = row + (png_size_t)row_info->rowbytes,
|
|
pp = prev_row + (png_size_t)row_info->rowbytes,
|
|
lp = row + (png_size_t)row_info->rowbytes - bpp,
|
|
cp = prev_row + (png_size_t)row_info->rowbytes - bpp;
|
|
i > 0; i--, rp--, lp--, pp--, cp--)
|
|
{
|
|
int a, b, c, pa, pb, pc, p;
|
|
|
|
b = *pp;
|
|
if (i > bpp)
|
|
{
|
|
c = *cp;
|
|
a = *lp;
|
|
}
|
|
else
|
|
{
|
|
a = c = 0;
|
|
}
|
|
p = a + b - c;
|
|
pa = abs(p - a);
|
|
pb = abs(p - b);
|
|
pc = abs(p - c);
|
|
|
|
if (pa <= pb && pa <= pc)
|
|
p = a;
|
|
else if (pb <= pc)
|
|
p = b;
|
|
else
|
|
p = c;
|
|
|
|
*rp = (png_byte)(((int)*rp - p) & 0xff);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|