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william |
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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 1.2.37 [June 4, 2009] |
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* Copyright (c) 1998-2009 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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#define PNG_INTERNAL |
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#include "png.h" |
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#ifdef PNG_WRITE_SUPPORTED |
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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_structp png_ptr) |
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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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#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) |
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if (png_ptr->transformations & PNG_USER_TRANSFORM) |
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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 function */ |
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(png_ptr, /* png_ptr */ |
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&(png_ptr->row_info), /* row_info: */ |
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/* png_uint_32 width; width of row */ |
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/* png_uint_32 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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#if defined(PNG_WRITE_FILLER_SUPPORTED) |
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if (png_ptr->transformations & PNG_FILLER) |
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png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1, |
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png_ptr->flags); |
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#endif |
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#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) |
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if (png_ptr->transformations & PNG_PACKSWAP) |
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png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1); |
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#endif |
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#if defined(PNG_WRITE_PACK_SUPPORTED) |
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if (png_ptr->transformations & PNG_PACK) |
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png_do_pack(&(png_ptr->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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#if defined(PNG_WRITE_SWAP_SUPPORTED) |
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if (png_ptr->transformations & PNG_SWAP_BYTES) |
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png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1); |
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#endif |
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#if defined(PNG_WRITE_SHIFT_SUPPORTED) |
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if (png_ptr->transformations & PNG_SHIFT) |
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png_do_shift(&(png_ptr->row_info), png_ptr->row_buf + 1, |
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&(png_ptr->shift)); |
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#endif |
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#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) |
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if (png_ptr->transformations & PNG_SWAP_ALPHA) |
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png_do_write_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); |
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#endif |
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#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) |
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if (png_ptr->transformations & PNG_INVERT_ALPHA) |
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png_do_write_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); |
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#endif |
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#if defined(PNG_WRITE_BGR_SUPPORTED) |
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if (png_ptr->transformations & PNG_BGR) |
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png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1); |
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#endif |
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#if defined(PNG_WRITE_INVERT_SUPPORTED) |
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if (png_ptr->transformations & PNG_INVERT_MONO) |
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png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1); |
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#endif |
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} |
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#if defined(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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void /* PRIVATE */ |
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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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#if defined(PNG_USELESS_TESTS_SUPPORTED) |
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row != NULL && row_info != NULL && |
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#endif |
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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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int shift, 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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int shift, 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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} |
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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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#if defined(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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void /* PRIVATE */ |
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png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth) |
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{ |
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png_debug(1, "in png_do_shift"); |
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#if defined(PNG_USELESS_TESTS_SUPPORTED) |
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if (row != NULL && row_info != NULL && |
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#else |
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if ( |
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#endif |
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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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int channels = 0; |
| 228 |
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if (row_info->color_type & PNG_COLOR_MASK_COLOR) |
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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++; |
| 240 |
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} |
| 241 |
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else |
| 242 |
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{ |
| 243 |
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shift_start[channels] = row_info->bit_depth - bit_depth->gray; |
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shift_dec[channels] = bit_depth->gray; |
| 245 |
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channels++; |
| 246 |
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} |
| 247 |
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if (row_info->color_type & PNG_COLOR_MASK_ALPHA) |
| 248 |
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{ |
| 249 |
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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++; |
| 252 |
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} |
| 253 |
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| 254 |
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/* With low row depths, could only be grayscale, so one channel */ |
| 255 |
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if (row_info->bit_depth < 8) |
| 256 |
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{ |
| 257 |
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png_bytep bp = row; |
| 258 |
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png_uint_32 i; |
| 259 |
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png_byte mask; |
| 260 |
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png_uint_32 row_bytes = row_info->rowbytes; |
| 261 |
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| 262 |
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if (bit_depth->gray == 1 && row_info->bit_depth == 2) |
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mask = 0x55; |
| 264 |
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else if (row_info->bit_depth == 4 && bit_depth->gray == 3) |
| 265 |
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mask = 0x11; |
| 266 |
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else |
| 267 |
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mask = 0xff; |
| 268 |
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| 269 |
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for (i = 0; i < row_bytes; i++, bp++) |
| 270 |
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{ |
| 271 |
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png_uint_16 v; |
| 272 |
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int j; |
| 273 |
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| 274 |
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v = *bp; |
| 275 |
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*bp = 0; |
| 276 |
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for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0]) |
| 277 |
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{ |
| 278 |
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if (j > 0) |
| 279 |
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*bp |= (png_byte)((v << j) & 0xff); |
| 280 |
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else |
| 281 |
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*bp |= (png_byte)((v >> (-j)) & mask); |
| 282 |
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} |
| 283 |
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} |
| 284 |
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} |
| 285 |
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else if (row_info->bit_depth == 8) |
| 286 |
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{ |
| 287 |
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png_bytep bp = row; |
| 288 |
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png_uint_32 i; |
| 289 |
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png_uint_32 istop = channels * row_info->width; |
| 290 |
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| 291 |
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for (i = 0; i < istop; i++, bp++) |
| 292 |
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{ |
| 293 |
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| 294 |
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png_uint_16 v; |
| 295 |
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int j; |
| 296 |
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int c = (int)(i%channels); |
| 297 |
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| 298 |
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v = *bp; |
| 299 |
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*bp = 0; |
| 300 |
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for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c]) |
| 301 |
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{ |
| 302 |
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if (j > 0) |
| 303 |
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*bp |= (png_byte)((v << j) & 0xff); |
| 304 |
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else |
| 305 |
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*bp |= (png_byte)((v >> (-j)) & 0xff); |
| 306 |
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} |
| 307 |
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} |
| 308 |
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} |
| 309 |
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else |
| 310 |
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{ |
| 311 |
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png_bytep bp; |
| 312 |
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png_uint_32 i; |
| 313 |
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png_uint_32 istop = channels * row_info->width; |
| 314 |
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| 315 |
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for (bp = row, i = 0; i < istop; i++) |
| 316 |
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{ |
| 317 |
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int c = (int)(i%channels); |
| 318 |
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png_uint_16 value, v; |
| 319 |
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int j; |
| 320 |
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| 321 |
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v = (png_uint_16)(((png_uint_16)(*bp) << 8) + *(bp + 1)); |
| 322 |
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value = 0; |
| 323 |
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for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c]) |
| 324 |
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{ |
| 325 |
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if (j > 0) |
| 326 |
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value |= (png_uint_16)((v << j) & (png_uint_16)0xffff); |
| 327 |
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else |
| 328 |
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value |= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff); |
| 329 |
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} |
| 330 |
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*bp++ = (png_byte)(value >> 8); |
| 331 |
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*bp++ = (png_byte)(value & 0xff); |
| 332 |
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} |
| 333 |
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} |
| 334 |
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} |
| 335 |
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} |
| 336 |
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#endif |
| 337 |
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| 338 |
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#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) |
| 339 |
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void /* PRIVATE */ |
| 340 |
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png_do_write_swap_alpha(png_row_infop row_info, png_bytep row) |
| 341 |
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{ |
| 342 |
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png_debug(1, "in png_do_write_swap_alpha"); |
| 343 |
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#if defined(PNG_USELESS_TESTS_SUPPORTED) |
| 344 |
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if (row != NULL && row_info != NULL) |
| 345 |
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#endif |
| 346 |
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{ |
| 347 |
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if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| 348 |
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{ |
| 349 |
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/* This converts from ARGB to RGBA */ |
| 350 |
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if (row_info->bit_depth == 8) |
| 351 |
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{ |
| 352 |
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png_bytep sp, dp; |
| 353 |
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png_uint_32 i; |
| 354 |
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png_uint_32 row_width = row_info->width; |
| 355 |
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for (i = 0, sp = dp = row; i < row_width; i++) |
| 356 |
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{ |
| 357 |
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png_byte save = *(sp++); |
| 358 |
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*(dp++) = *(sp++); |
| 359 |
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*(dp++) = *(sp++); |
| 360 |
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*(dp++) = *(sp++); |
| 361 |
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*(dp++) = save; |
| 362 |
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} |
| 363 |
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} |
| 364 |
|
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/* This converts from AARRGGBB to RRGGBBAA */ |
| 365 |
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else |
| 366 |
|
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{ |
| 367 |
|
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png_bytep sp, dp; |
| 368 |
|
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png_uint_32 i; |
| 369 |
|
|
png_uint_32 row_width = row_info->width; |
| 370 |
|
|
|
| 371 |
|
|
for (i = 0, sp = dp = row; i < row_width; i++) |
| 372 |
|
|
{ |
| 373 |
|
|
png_byte save[2]; |
| 374 |
|
|
save[0] = *(sp++); |
| 375 |
|
|
save[1] = *(sp++); |
| 376 |
|
|
*(dp++) = *(sp++); |
| 377 |
|
|
*(dp++) = *(sp++); |
| 378 |
|
|
*(dp++) = *(sp++); |
| 379 |
|
|
*(dp++) = *(sp++); |
| 380 |
|
|
*(dp++) = *(sp++); |
| 381 |
|
|
*(dp++) = *(sp++); |
| 382 |
|
|
*(dp++) = save[0]; |
| 383 |
|
|
*(dp++) = save[1]; |
| 384 |
|
|
} |
| 385 |
|
|
} |
| 386 |
|
|
} |
| 387 |
|
|
else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) |
| 388 |
|
|
{ |
| 389 |
|
|
/* This converts from AG to GA */ |
| 390 |
|
|
if (row_info->bit_depth == 8) |
| 391 |
|
|
{ |
| 392 |
|
|
png_bytep sp, dp; |
| 393 |
|
|
png_uint_32 i; |
| 394 |
|
|
png_uint_32 row_width = row_info->width; |
| 395 |
|
|
|
| 396 |
|
|
for (i = 0, sp = dp = row; i < row_width; i++) |
| 397 |
|
|
{ |
| 398 |
|
|
png_byte save = *(sp++); |
| 399 |
|
|
*(dp++) = *(sp++); |
| 400 |
|
|
*(dp++) = save; |
| 401 |
|
|
} |
| 402 |
|
|
} |
| 403 |
|
|
/* This converts from AAGG to GGAA */ |
| 404 |
|
|
else |
| 405 |
|
|
{ |
| 406 |
|
|
png_bytep sp, dp; |
| 407 |
|
|
png_uint_32 i; |
| 408 |
|
|
png_uint_32 row_width = row_info->width; |
| 409 |
|
|
|
| 410 |
|
|
for (i = 0, sp = dp = row; i < row_width; i++) |
| 411 |
|
|
{ |
| 412 |
|
|
png_byte save[2]; |
| 413 |
|
|
save[0] = *(sp++); |
| 414 |
|
|
save[1] = *(sp++); |
| 415 |
|
|
*(dp++) = *(sp++); |
| 416 |
|
|
*(dp++) = *(sp++); |
| 417 |
|
|
*(dp++) = save[0]; |
| 418 |
|
|
*(dp++) = save[1]; |
| 419 |
|
|
} |
| 420 |
|
|
} |
| 421 |
|
|
} |
| 422 |
|
|
} |
| 423 |
|
|
} |
| 424 |
|
|
#endif |
| 425 |
|
|
|
| 426 |
|
|
#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) |
| 427 |
|
|
void /* PRIVATE */ |
| 428 |
|
|
png_do_write_invert_alpha(png_row_infop row_info, png_bytep row) |
| 429 |
|
|
{ |
| 430 |
|
|
png_debug(1, "in png_do_write_invert_alpha"); |
| 431 |
|
|
#if defined(PNG_USELESS_TESTS_SUPPORTED) |
| 432 |
|
|
if (row != NULL && row_info != NULL) |
| 433 |
|
|
#endif |
| 434 |
|
|
{ |
| 435 |
|
|
if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| 436 |
|
|
{ |
| 437 |
|
|
/* This inverts the alpha channel in RGBA */ |
| 438 |
|
|
if (row_info->bit_depth == 8) |
| 439 |
|
|
{ |
| 440 |
|
|
png_bytep sp, dp; |
| 441 |
|
|
png_uint_32 i; |
| 442 |
|
|
png_uint_32 row_width = row_info->width; |
| 443 |
|
|
for (i = 0, sp = dp = row; i < row_width; i++) |
| 444 |
|
|
{ |
| 445 |
|
|
/* Does nothing |
| 446 |
|
|
*(dp++) = *(sp++); |
| 447 |
|
|
*(dp++) = *(sp++); |
| 448 |
|
|
*(dp++) = *(sp++); |
| 449 |
|
|
*/ |
| 450 |
|
|
sp+=3; dp = sp; |
| 451 |
|
|
*(dp++) = (png_byte)(255 - *(sp++)); |
| 452 |
|
|
} |
| 453 |
|
|
} |
| 454 |
|
|
/* This inverts the alpha channel in RRGGBBAA */ |
| 455 |
|
|
else |
| 456 |
|
|
{ |
| 457 |
|
|
png_bytep sp, dp; |
| 458 |
|
|
png_uint_32 i; |
| 459 |
|
|
png_uint_32 row_width = row_info->width; |
| 460 |
|
|
|
| 461 |
|
|
for (i = 0, sp = dp = row; i < row_width; i++) |
| 462 |
|
|
{ |
| 463 |
|
|
/* Does nothing |
| 464 |
|
|
*(dp++) = *(sp++); |
| 465 |
|
|
*(dp++) = *(sp++); |
| 466 |
|
|
*(dp++) = *(sp++); |
| 467 |
|
|
*(dp++) = *(sp++); |
| 468 |
|
|
*(dp++) = *(sp++); |
| 469 |
|
|
*(dp++) = *(sp++); |
| 470 |
|
|
*/ |
| 471 |
|
|
sp+=6; dp = sp; |
| 472 |
|
|
*(dp++) = (png_byte)(255 - *(sp++)); |
| 473 |
|
|
*(dp++) = (png_byte)(255 - *(sp++)); |
| 474 |
|
|
} |
| 475 |
|
|
} |
| 476 |
|
|
} |
| 477 |
|
|
else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) |
| 478 |
|
|
{ |
| 479 |
|
|
/* This inverts the alpha channel in GA */ |
| 480 |
|
|
if (row_info->bit_depth == 8) |
| 481 |
|
|
{ |
| 482 |
|
|
png_bytep sp, dp; |
| 483 |
|
|
png_uint_32 i; |
| 484 |
|
|
png_uint_32 row_width = row_info->width; |
| 485 |
|
|
|
| 486 |
|
|
for (i = 0, sp = dp = row; i < row_width; i++) |
| 487 |
|
|
{ |
| 488 |
|
|
*(dp++) = *(sp++); |
| 489 |
|
|
*(dp++) = (png_byte)(255 - *(sp++)); |
| 490 |
|
|
} |
| 491 |
|
|
} |
| 492 |
|
|
/* This inverts the alpha channel in GGAA */ |
| 493 |
|
|
else |
| 494 |
|
|
{ |
| 495 |
|
|
png_bytep sp, dp; |
| 496 |
|
|
png_uint_32 i; |
| 497 |
|
|
png_uint_32 row_width = row_info->width; |
| 498 |
|
|
|
| 499 |
|
|
for (i = 0, sp = dp = row; i < row_width; i++) |
| 500 |
|
|
{ |
| 501 |
|
|
/* Does nothing |
| 502 |
|
|
*(dp++) = *(sp++); |
| 503 |
|
|
*(dp++) = *(sp++); |
| 504 |
|
|
*/ |
| 505 |
|
|
sp+=2; dp = sp; |
| 506 |
|
|
*(dp++) = (png_byte)(255 - *(sp++)); |
| 507 |
|
|
*(dp++) = (png_byte)(255 - *(sp++)); |
| 508 |
|
|
} |
| 509 |
|
|
} |
| 510 |
|
|
} |
| 511 |
|
|
} |
| 512 |
|
|
} |
| 513 |
|
|
#endif |
| 514 |
|
|
|
| 515 |
|
|
#if defined(PNG_MNG_FEATURES_SUPPORTED) |
| 516 |
|
|
/* Undoes intrapixel differencing */ |
| 517 |
|
|
void /* PRIVATE */ |
| 518 |
|
|
png_do_write_intrapixel(png_row_infop row_info, png_bytep row) |
| 519 |
|
|
{ |
| 520 |
|
|
png_debug(1, "in png_do_write_intrapixel"); |
| 521 |
|
|
if ( |
| 522 |
|
|
#if defined(PNG_USELESS_TESTS_SUPPORTED) |
| 523 |
|
|
row != NULL && row_info != NULL && |
| 524 |
|
|
#endif |
| 525 |
|
|
(row_info->color_type & PNG_COLOR_MASK_COLOR)) |
| 526 |
|
|
{ |
| 527 |
|
|
int bytes_per_pixel; |
| 528 |
|
|
png_uint_32 row_width = row_info->width; |
| 529 |
|
|
if (row_info->bit_depth == 8) |
| 530 |
|
|
{ |
| 531 |
|
|
png_bytep rp; |
| 532 |
|
|
png_uint_32 i; |
| 533 |
|
|
|
| 534 |
|
|
if (row_info->color_type == PNG_COLOR_TYPE_RGB) |
| 535 |
|
|
bytes_per_pixel = 3; |
| 536 |
|
|
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| 537 |
|
|
bytes_per_pixel = 4; |
| 538 |
|
|
else |
| 539 |
|
|
return; |
| 540 |
|
|
|
| 541 |
|
|
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) |
| 542 |
|
|
{ |
| 543 |
|
|
*(rp) = (png_byte)((*rp - *(rp+1))&0xff); |
| 544 |
|
|
*(rp+2) = (png_byte)((*(rp+2) - *(rp+1))&0xff); |
| 545 |
|
|
} |
| 546 |
|
|
} |
| 547 |
|
|
else if (row_info->bit_depth == 16) |
| 548 |
|
|
{ |
| 549 |
|
|
png_bytep rp; |
| 550 |
|
|
png_uint_32 i; |
| 551 |
|
|
|
| 552 |
|
|
if (row_info->color_type == PNG_COLOR_TYPE_RGB) |
| 553 |
|
|
bytes_per_pixel = 6; |
| 554 |
|
|
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| 555 |
|
|
bytes_per_pixel = 8; |
| 556 |
|
|
else |
| 557 |
|
|
return; |
| 558 |
|
|
|
| 559 |
|
|
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) |
| 560 |
|
|
{ |
| 561 |
|
|
png_uint_32 s0 = (*(rp ) << 8) | *(rp+1); |
| 562 |
|
|
png_uint_32 s1 = (*(rp+2) << 8) | *(rp+3); |
| 563 |
|
|
png_uint_32 s2 = (*(rp+4) << 8) | *(rp+5); |
| 564 |
|
|
png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL); |
| 565 |
|
|
png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL); |
| 566 |
|
|
*(rp ) = (png_byte)((red >> 8) & 0xff); |
| 567 |
|
|
*(rp+1) = (png_byte)(red & 0xff); |
| 568 |
|
|
*(rp+4) = (png_byte)((blue >> 8) & 0xff); |
| 569 |
|
|
*(rp+5) = (png_byte)(blue & 0xff); |
| 570 |
|
|
} |
| 571 |
|
|
} |
| 572 |
|
|
} |
| 573 |
|
|
} |
| 574 |
|
|
#endif /* PNG_MNG_FEATURES_SUPPORTED */ |
| 575 |
|
|
#endif /* PNG_WRITE_SUPPORTED */ |
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