577 lines
15 KiB
C
577 lines
15 KiB
C
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/* pngwtran.c - transforms the data in a row for PNG writers
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*
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* Last changed in libpng 1.6.35 [July 15, 2018]
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* Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
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* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
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* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
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*
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* This code is released under the libpng license.
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* For conditions of distribution and use, see the disclaimer
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* and license in png.h
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*/
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#include "pngpriv.h"
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#ifdef PNG_WRITE_SUPPORTED
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#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
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#ifdef PNG_WRITE_PACK_SUPPORTED
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/* Pack pixels into bytes. Pass the true bit depth in bit_depth. The
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* row_info bit depth should be 8 (one pixel per byte). The channels
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* should be 1 (this only happens on grayscale and paletted images).
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*/
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static void
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png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
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{
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png_debug(1, "in png_do_pack");
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if (row_info->bit_depth == 8 &&
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row_info->channels == 1)
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{
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switch ((int)bit_depth)
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{
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case 1:
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{
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png_bytep sp, dp;
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int mask, v;
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png_uint_32 i;
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png_uint_32 row_width = row_info->width;
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sp = row;
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dp = row;
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mask = 0x80;
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v = 0;
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for (i = 0; i < row_width; i++)
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{
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if (*sp != 0)
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v |= mask;
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sp++;
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if (mask > 1)
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mask >>= 1;
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else
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{
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mask = 0x80;
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*dp = (png_byte)v;
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dp++;
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v = 0;
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}
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}
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if (mask != 0x80)
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*dp = (png_byte)v;
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break;
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}
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case 2:
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{
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png_bytep sp, dp;
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unsigned int shift;
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int v;
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png_uint_32 i;
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png_uint_32 row_width = row_info->width;
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sp = row;
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dp = row;
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shift = 6;
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v = 0;
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for (i = 0; i < row_width; i++)
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{
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png_byte value;
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value = (png_byte)(*sp & 0x03);
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v |= (value << shift);
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if (shift == 0)
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{
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shift = 6;
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*dp = (png_byte)v;
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dp++;
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v = 0;
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}
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else
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shift -= 2;
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sp++;
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}
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if (shift != 6)
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*dp = (png_byte)v;
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break;
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}
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case 4:
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{
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png_bytep sp, dp;
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unsigned int shift;
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int v;
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png_uint_32 i;
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png_uint_32 row_width = row_info->width;
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sp = row;
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dp = row;
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shift = 4;
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v = 0;
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for (i = 0; i < row_width; i++)
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{
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png_byte value;
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value = (png_byte)(*sp & 0x0f);
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v |= (value << shift);
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if (shift == 0)
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{
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shift = 4;
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*dp = (png_byte)v;
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dp++;
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v = 0;
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}
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else
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shift -= 4;
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sp++;
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}
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if (shift != 4)
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*dp = (png_byte)v;
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break;
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}
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default:
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break;
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}
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row_info->bit_depth = (png_byte)bit_depth;
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row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
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row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
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row_info->width);
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}
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}
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#endif
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#ifdef PNG_WRITE_SHIFT_SUPPORTED
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/* Shift pixel values to take advantage of whole range. Pass the
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* true number of bits in bit_depth. The row should be packed
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* according to row_info->bit_depth. Thus, if you had a row of
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* bit depth 4, but the pixels only had values from 0 to 7, you
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* would pass 3 as bit_depth, and this routine would translate the
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* data to 0 to 15.
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*/
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static void
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png_do_shift(png_row_infop row_info, png_bytep row,
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png_const_color_8p bit_depth)
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{
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png_debug(1, "in png_do_shift");
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if (row_info->color_type != PNG_COLOR_TYPE_PALETTE)
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{
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int shift_start[4], shift_dec[4];
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unsigned int channels = 0;
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if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
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{
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shift_start[channels] = row_info->bit_depth - bit_depth->red;
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shift_dec[channels] = bit_depth->red;
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channels++;
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shift_start[channels] = row_info->bit_depth - bit_depth->green;
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shift_dec[channels] = bit_depth->green;
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channels++;
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shift_start[channels] = row_info->bit_depth - bit_depth->blue;
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shift_dec[channels] = bit_depth->blue;
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channels++;
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}
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else
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{
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shift_start[channels] = row_info->bit_depth - bit_depth->gray;
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shift_dec[channels] = bit_depth->gray;
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channels++;
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}
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if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
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{
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shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
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shift_dec[channels] = bit_depth->alpha;
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channels++;
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}
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/* With low row depths, could only be grayscale, so one channel */
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if (row_info->bit_depth < 8)
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{
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png_bytep bp = row;
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size_t i;
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unsigned int mask;
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size_t row_bytes = row_info->rowbytes;
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if (bit_depth->gray == 1 && row_info->bit_depth == 2)
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mask = 0x55;
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else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
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mask = 0x11;
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else
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mask = 0xff;
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for (i = 0; i < row_bytes; i++, bp++)
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{
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int j;
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unsigned int v, out;
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v = *bp;
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out = 0;
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for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
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{
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if (j > 0)
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out |= v << j;
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else
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out |= (v >> (-j)) & mask;
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}
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*bp = (png_byte)(out & 0xff);
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}
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}
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else if (row_info->bit_depth == 8)
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{
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png_bytep bp = row;
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png_uint_32 i;
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png_uint_32 istop = channels * row_info->width;
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for (i = 0; i < istop; i++, bp++)
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{
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const unsigned int c = i%channels;
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int j;
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unsigned int v, out;
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v = *bp;
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out = 0;
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for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
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{
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if (j > 0)
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out |= v << j;
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else
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out |= v >> (-j);
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}
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*bp = (png_byte)(out & 0xff);
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}
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}
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else
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{
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png_bytep bp;
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png_uint_32 i;
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png_uint_32 istop = channels * row_info->width;
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for (bp = row, i = 0; i < istop; i++)
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{
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const unsigned int c = i%channels;
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int j;
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unsigned int value, v;
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v = png_get_uint_16(bp);
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value = 0;
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for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
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{
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if (j > 0)
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value |= v << j;
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else
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value |= v >> (-j);
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}
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*bp++ = (png_byte)((value >> 8) & 0xff);
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*bp++ = (png_byte)(value & 0xff);
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}
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}
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}
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}
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#endif
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#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
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static void
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png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
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{
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png_debug(1, "in png_do_write_swap_alpha");
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{
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if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
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{
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if (row_info->bit_depth == 8)
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{
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/* This converts from ARGB to RGBA */
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png_bytep sp, dp;
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png_uint_32 i;
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png_uint_32 row_width = row_info->width;
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for (i = 0, sp = dp = row; i < row_width; i++)
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{
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png_byte save = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = save;
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}
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}
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#ifdef PNG_WRITE_16BIT_SUPPORTED
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else
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{
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/* This converts from AARRGGBB to RRGGBBAA */
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png_bytep sp, dp;
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png_uint_32 i;
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png_uint_32 row_width = row_info->width;
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for (i = 0, sp = dp = row; i < row_width; i++)
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{
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png_byte save[2];
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save[0] = *(sp++);
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save[1] = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = save[0];
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*(dp++) = save[1];
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}
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}
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#endif /* WRITE_16BIT */
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}
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else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
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{
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if (row_info->bit_depth == 8)
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{
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/* This converts from AG to GA */
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png_bytep sp, dp;
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png_uint_32 i;
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png_uint_32 row_width = row_info->width;
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for (i = 0, sp = dp = row; i < row_width; i++)
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{
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png_byte save = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = save;
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}
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}
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#ifdef PNG_WRITE_16BIT_SUPPORTED
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else
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{
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/* This converts from AAGG to GGAA */
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png_bytep sp, dp;
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png_uint_32 i;
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png_uint_32 row_width = row_info->width;
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for (i = 0, sp = dp = row; i < row_width; i++)
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{
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png_byte save[2];
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save[0] = *(sp++);
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save[1] = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = save[0];
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*(dp++) = save[1];
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}
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}
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#endif /* WRITE_16BIT */
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}
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}
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}
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#endif
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#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
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static void
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png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
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{
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png_debug(1, "in png_do_write_invert_alpha");
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{
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if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
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{
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if (row_info->bit_depth == 8)
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{
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/* This inverts the alpha channel in RGBA */
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png_bytep sp, dp;
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png_uint_32 i;
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png_uint_32 row_width = row_info->width;
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for (i = 0, sp = dp = row; i < row_width; i++)
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{
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/* Does nothing
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*/
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sp+=3; dp = sp;
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*dp = (png_byte)(255 - *(sp++));
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}
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}
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#ifdef PNG_WRITE_16BIT_SUPPORTED
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else
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{
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/* This inverts the alpha channel in RRGGBBAA */
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png_bytep sp, dp;
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png_uint_32 i;
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png_uint_32 row_width = row_info->width;
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for (i = 0, sp = dp = row; i < row_width; i++)
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{
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/* Does nothing
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*/
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sp+=6; dp = sp;
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*(dp++) = (png_byte)(255 - *(sp++));
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*dp = (png_byte)(255 - *(sp++));
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}
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}
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#endif /* WRITE_16BIT */
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}
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else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
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{
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if (row_info->bit_depth == 8)
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{
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/* This inverts the alpha channel in GA */
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png_bytep sp, dp;
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png_uint_32 i;
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png_uint_32 row_width = row_info->width;
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for (i = 0, sp = dp = row; i < row_width; i++)
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{
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*(dp++) = *(sp++);
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*(dp++) = (png_byte)(255 - *(sp++));
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}
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}
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#ifdef PNG_WRITE_16BIT_SUPPORTED
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else
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{
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/* This inverts the alpha channel in GGAA */
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png_bytep sp, dp;
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png_uint_32 i;
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png_uint_32 row_width = row_info->width;
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for (i = 0, sp = dp = row; i < row_width; i++)
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{
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/* Does nothing
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*(dp++) = *(sp++);
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*(dp++) = *(sp++);
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*/
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sp+=2; dp = sp;
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*(dp++) = (png_byte)(255 - *(sp++));
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*dp = (png_byte)(255 - *(sp++));
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}
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}
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#endif /* WRITE_16BIT */
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}
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}
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}
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#endif
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/* Transform the data according to the user's wishes. The order of
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* transformations is significant.
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*/
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void /* PRIVATE */
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png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
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{
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png_debug(1, "in png_do_write_transformations");
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if (png_ptr == NULL)
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return;
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#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
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if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
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if (png_ptr->write_user_transform_fn != NULL)
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(*(png_ptr->write_user_transform_fn)) /* User write transform
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function */
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(png_ptr, /* png_ptr */
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row_info, /* row_info: */
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/* png_uint_32 width; width of row */
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/* size_t rowbytes; number of bytes in row */
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/* png_byte color_type; color type of pixels */
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/* png_byte bit_depth; bit depth of samples */
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/* png_byte channels; number of channels (1-4) */
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/* png_byte pixel_depth; bits per pixel (depth*channels) */
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png_ptr->row_buf + 1); /* start of pixel data for row */
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#endif
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#ifdef PNG_WRITE_FILLER_SUPPORTED
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if ((png_ptr->transformations & PNG_FILLER) != 0)
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png_do_strip_channel(row_info, png_ptr->row_buf + 1,
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!(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
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#endif
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#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
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if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
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png_do_packswap(row_info, png_ptr->row_buf + 1);
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#endif
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#ifdef PNG_WRITE_PACK_SUPPORTED
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if ((png_ptr->transformations & PNG_PACK) != 0)
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png_do_pack(row_info, png_ptr->row_buf + 1,
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(png_uint_32)png_ptr->bit_depth);
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#endif
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#ifdef PNG_WRITE_SWAP_SUPPORTED
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# ifdef PNG_16BIT_SUPPORTED
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if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
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png_do_swap(row_info, png_ptr->row_buf + 1);
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# endif
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#endif
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#ifdef PNG_WRITE_SHIFT_SUPPORTED
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if ((png_ptr->transformations & PNG_SHIFT) != 0)
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png_do_shift(row_info, png_ptr->row_buf + 1,
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&(png_ptr->shift));
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#endif
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#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
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if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
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png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
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#endif
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#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
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if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
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png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
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#endif
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#ifdef PNG_WRITE_BGR_SUPPORTED
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if ((png_ptr->transformations & PNG_BGR) != 0)
|
|
png_do_bgr(row_info, png_ptr->row_buf + 1);
|
|
#endif
|
|
|
|
#ifdef PNG_WRITE_INVERT_SUPPORTED
|
|
if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
|
|
png_do_invert(row_info, png_ptr->row_buf + 1);
|
|
#endif
|
|
}
|
|
#endif /* WRITE_TRANSFORMS */
|
|
#endif /* WRITE */
|