Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 1 | |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 2 | /* pngwtran.c - transforms the data in a row for PNG writers |
Glenn Randers-Pehrson | b6ce43d | 1998-01-01 07:13:13 -0600 | [diff] [blame] | 3 | * |
Glenn Randers-Pehrson | bfbf865 | 2009-06-26 21:46:52 -0500 | [diff] [blame^] | 4 | * Last changed in libpng 1.4.0 [June 27, 2009] |
Glenn Randers-Pehrson | 79134c6 | 2009-02-14 10:32:18 -0600 | [diff] [blame] | 5 | * Copyright (c) 1998-2009 Glenn Randers-Pehrson |
Glenn Randers-Pehrson | d436672 | 2000-06-04 14:29:29 -0500 | [diff] [blame] | 6 | * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) |
| 7 | * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) |
Glenn Randers-Pehrson | 3e61d79 | 2009-06-24 09:31:28 -0500 | [diff] [blame] | 8 | * |
Glenn Randers-Pehrson | bfbf865 | 2009-06-26 21:46:52 -0500 | [diff] [blame^] | 9 | * This code is released under the libpng license. |
Glenn Randers-Pehrson | c332bbc | 2009-06-25 13:43:50 -0500 | [diff] [blame] | 10 | * For conditions of distribution and use, see the disclaimer |
Glenn Randers-Pehrson | 037023b | 2009-06-24 10:27:36 -0500 | [diff] [blame] | 11 | * and license in png.h |
Glenn Randers-Pehrson | b6ce43d | 1998-01-01 07:13:13 -0600 | [diff] [blame] | 12 | */ |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 13 | |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 14 | #include "png.h" |
Glenn Randers-Pehrson | 3097f61 | 2001-05-07 14:52:45 -0500 | [diff] [blame] | 15 | #ifdef PNG_WRITE_SUPPORTED |
Glenn Randers-Pehrson | beb572e | 2006-08-19 13:59:24 -0500 | [diff] [blame] | 16 | #include "pngpriv.h" |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 17 | |
Glenn Randers-Pehrson | 345bc27 | 1998-06-14 14:43:31 -0500 | [diff] [blame] | 18 | /* Transform the data according to the user's wishes. The order of |
Glenn Randers-Pehrson | b6ce43d | 1998-01-01 07:13:13 -0600 | [diff] [blame] | 19 | * transformations is significant. |
| 20 | */ |
Glenn Randers-Pehrson | 7529457 | 2000-05-06 14:09:57 -0500 | [diff] [blame] | 21 | void /* PRIVATE */ |
Guy Schalnat | 6d76471 | 1995-12-19 03:22:19 -0600 | [diff] [blame] | 22 | png_do_write_transformations(png_structp png_ptr) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 23 | { |
Glenn Randers-Pehrson | 51650b8 | 2008-08-05 07:44:42 -0500 | [diff] [blame] | 24 | png_debug(1, "in png_do_write_transformations"); |
Glenn Randers-Pehrson | 08a3343 | 1998-03-07 06:06:55 -0600 | [diff] [blame] | 25 | |
Glenn Randers-Pehrson | 166c5a3 | 1999-12-10 09:43:02 -0600 | [diff] [blame] | 26 | if (png_ptr == NULL) |
| 27 | return; |
| 28 | |
Glenn Randers-Pehrson | 08a3343 | 1998-03-07 06:06:55 -0600 | [diff] [blame] | 29 | #if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) |
| 30 | if (png_ptr->transformations & PNG_USER_TRANSFORM) |
Glenn Randers-Pehrson | 145f5c8 | 2008-07-10 09:13:13 -0500 | [diff] [blame] | 31 | if (png_ptr->write_user_transform_fn != NULL) |
Glenn Randers-Pehrson | 4bb4d01 | 2009-05-20 12:45:29 -0500 | [diff] [blame] | 32 | (*(png_ptr->write_user_transform_fn)) /* User write transform function */ |
Glenn Randers-Pehrson | 08a3343 | 1998-03-07 06:06:55 -0600 | [diff] [blame] | 33 | (png_ptr, /* png_ptr */ |
| 34 | &(png_ptr->row_info), /* row_info: */ |
| 35 | /* png_uint_32 width; width of row */ |
| 36 | /* png_uint_32 rowbytes; number of bytes in row */ |
| 37 | /* png_byte color_type; color type of pixels */ |
| 38 | /* png_byte bit_depth; bit depth of samples */ |
| 39 | /* png_byte channels; number of channels (1-4) */ |
| 40 | /* png_byte pixel_depth; bits per pixel (depth*channels) */ |
| 41 | png_ptr->row_buf + 1); /* start of pixel data for row */ |
| 42 | #endif |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 43 | #if defined(PNG_WRITE_FILLER_SUPPORTED) |
Glenn Randers-Pehrson | 73b029f | 2004-11-26 17:28:09 -0600 | [diff] [blame] | 44 | if (png_ptr->transformations & PNG_FILLER) |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 45 | png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1, |
Glenn Randers-Pehrson | 4093607 | 2004-11-20 11:18:40 -0600 | [diff] [blame] | 46 | png_ptr->flags); |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 47 | #endif |
Glenn Randers-Pehrson | 46f61e2 | 1998-01-30 21:45:12 -0600 | [diff] [blame] | 48 | #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) |
| 49 | if (png_ptr->transformations & PNG_PACKSWAP) |
| 50 | png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| 51 | #endif |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 52 | #if defined(PNG_WRITE_PACK_SUPPORTED) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 53 | if (png_ptr->transformations & PNG_PACK) |
| 54 | png_do_pack(&(png_ptr->row_info), png_ptr->row_buf + 1, |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 55 | (png_uint_32)png_ptr->bit_depth); |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 56 | #endif |
Glenn Randers-Pehrson | 5c6aeb2 | 1998-12-29 11:47:59 -0600 | [diff] [blame] | 57 | #if defined(PNG_WRITE_SWAP_SUPPORTED) |
| 58 | if (png_ptr->transformations & PNG_SWAP_BYTES) |
| 59 | png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| 60 | #endif |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 61 | #if defined(PNG_WRITE_SHIFT_SUPPORTED) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 62 | if (png_ptr->transformations & PNG_SHIFT) |
| 63 | png_do_shift(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| 64 | &(png_ptr->shift)); |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 65 | #endif |
Glenn Randers-Pehrson | cbe52d8 | 1998-02-28 07:00:24 -0600 | [diff] [blame] | 66 | #if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) |
| 67 | if (png_ptr->transformations & PNG_SWAP_ALPHA) |
| 68 | png_do_write_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| 69 | #endif |
Glenn Randers-Pehrson | 9c3ab68 | 2006-02-20 22:09:05 -0600 | [diff] [blame] | 70 | #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) |
| 71 | if (png_ptr->transformations & PNG_INVERT_ALPHA) |
| 72 | png_do_write_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| 73 | #endif |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 74 | #if defined(PNG_WRITE_BGR_SUPPORTED) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 75 | if (png_ptr->transformations & PNG_BGR) |
| 76 | png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1); |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 77 | #endif |
| 78 | #if defined(PNG_WRITE_INVERT_SUPPORTED) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 79 | if (png_ptr->transformations & PNG_INVERT_MONO) |
| 80 | png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1); |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 81 | #endif |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 82 | } |
| 83 | |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 84 | #if defined(PNG_WRITE_PACK_SUPPORTED) |
Glenn Randers-Pehrson | b6ce43d | 1998-01-01 07:13:13 -0600 | [diff] [blame] | 85 | /* Pack pixels into bytes. Pass the true bit depth in bit_depth. The |
| 86 | * row_info bit depth should be 8 (one pixel per byte). The channels |
| 87 | * should be 1 (this only happens on grayscale and paletted images). |
| 88 | */ |
Glenn Randers-Pehrson | 7529457 | 2000-05-06 14:09:57 -0500 | [diff] [blame] | 89 | void /* PRIVATE */ |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 90 | png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 91 | { |
Glenn Randers-Pehrson | 51650b8 | 2008-08-05 07:44:42 -0500 | [diff] [blame] | 92 | png_debug(1, "in png_do_pack"); |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 93 | if (row_info->bit_depth == 8 && |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 94 | row_info->channels == 1) |
| 95 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 96 | switch ((int)bit_depth) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 97 | { |
| 98 | case 1: |
| 99 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 100 | png_bytep sp, dp; |
| 101 | int mask, v; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 102 | png_uint_32 i; |
| 103 | png_uint_32 row_width = row_info->width; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 104 | |
| 105 | sp = row; |
| 106 | dp = row; |
| 107 | mask = 0x80; |
| 108 | v = 0; |
Glenn Randers-Pehrson | 5c6aeb2 | 1998-12-29 11:47:59 -0600 | [diff] [blame] | 109 | |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 110 | for (i = 0; i < row_width; i++) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 111 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 112 | if (*sp != 0) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 113 | v |= mask; |
| 114 | sp++; |
| 115 | if (mask > 1) |
| 116 | mask >>= 1; |
| 117 | else |
| 118 | { |
| 119 | mask = 0x80; |
Guy Schalnat | b2e01bd | 1996-01-26 01:38:47 -0600 | [diff] [blame] | 120 | *dp = (png_byte)v; |
| 121 | dp++; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 122 | v = 0; |
| 123 | } |
| 124 | } |
| 125 | if (mask != 0x80) |
Guy Schalnat | b2e01bd | 1996-01-26 01:38:47 -0600 | [diff] [blame] | 126 | *dp = (png_byte)v; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 127 | break; |
| 128 | } |
| 129 | case 2: |
| 130 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 131 | png_bytep sp, dp; |
| 132 | int shift, v; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 133 | png_uint_32 i; |
| 134 | png_uint_32 row_width = row_info->width; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 135 | |
| 136 | sp = row; |
| 137 | dp = row; |
| 138 | shift = 6; |
| 139 | v = 0; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 140 | for (i = 0; i < row_width; i++) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 141 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 142 | png_byte value; |
| 143 | |
Glenn Randers-Pehrson | 61c32d9 | 2000-02-04 23:40:16 -0600 | [diff] [blame] | 144 | value = (png_byte)(*sp & 0x03); |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 145 | v |= (value << shift); |
| 146 | if (shift == 0) |
| 147 | { |
| 148 | shift = 6; |
Guy Schalnat | b2e01bd | 1996-01-26 01:38:47 -0600 | [diff] [blame] | 149 | *dp = (png_byte)v; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 150 | dp++; |
| 151 | v = 0; |
| 152 | } |
| 153 | else |
| 154 | shift -= 2; |
| 155 | sp++; |
| 156 | } |
| 157 | if (shift != 6) |
Guy Schalnat | b2e01bd | 1996-01-26 01:38:47 -0600 | [diff] [blame] | 158 | *dp = (png_byte)v; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 159 | break; |
| 160 | } |
| 161 | case 4: |
| 162 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 163 | png_bytep sp, dp; |
| 164 | int shift, v; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 165 | png_uint_32 i; |
| 166 | png_uint_32 row_width = row_info->width; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 167 | |
| 168 | sp = row; |
| 169 | dp = row; |
| 170 | shift = 4; |
| 171 | v = 0; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 172 | for (i = 0; i < row_width; i++) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 173 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 174 | png_byte value; |
| 175 | |
Glenn Randers-Pehrson | 61c32d9 | 2000-02-04 23:40:16 -0600 | [diff] [blame] | 176 | value = (png_byte)(*sp & 0x0f); |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 177 | v |= (value << shift); |
| 178 | |
| 179 | if (shift == 0) |
| 180 | { |
| 181 | shift = 4; |
Guy Schalnat | b2e01bd | 1996-01-26 01:38:47 -0600 | [diff] [blame] | 182 | *dp = (png_byte)v; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 183 | dp++; |
| 184 | v = 0; |
| 185 | } |
| 186 | else |
| 187 | shift -= 4; |
| 188 | |
| 189 | sp++; |
| 190 | } |
| 191 | if (shift != 4) |
Guy Schalnat | b2e01bd | 1996-01-26 01:38:47 -0600 | [diff] [blame] | 192 | *dp = (png_byte)v; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 193 | break; |
| 194 | } |
| 195 | } |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 196 | row_info->bit_depth = (png_byte)bit_depth; |
| 197 | row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels); |
Glenn Randers-Pehrson | 272489d | 2004-08-04 06:34:52 -0500 | [diff] [blame] | 198 | row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, |
| 199 | row_info->width); |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 200 | } |
| 201 | } |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 202 | #endif |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 203 | |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 204 | #if defined(PNG_WRITE_SHIFT_SUPPORTED) |
Glenn Randers-Pehrson | b6ce43d | 1998-01-01 07:13:13 -0600 | [diff] [blame] | 205 | /* Shift pixel values to take advantage of whole range. Pass the |
| 206 | * true number of bits in bit_depth. The row should be packed |
| 207 | * according to row_info->bit_depth. Thus, if you had a row of |
| 208 | * bit depth 4, but the pixels only had values from 0 to 7, you |
| 209 | * would pass 3 as bit_depth, and this routine would translate the |
| 210 | * data to 0 to 15. |
| 211 | */ |
Glenn Randers-Pehrson | 7529457 | 2000-05-06 14:09:57 -0500 | [diff] [blame] | 212 | void /* PRIVATE */ |
Guy Schalnat | 6d76471 | 1995-12-19 03:22:19 -0600 | [diff] [blame] | 213 | png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 214 | { |
Glenn Randers-Pehrson | 51650b8 | 2008-08-05 07:44:42 -0500 | [diff] [blame] | 215 | png_debug(1, "in png_do_shift"); |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 216 | if ( |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 217 | row_info->color_type != PNG_COLOR_TYPE_PALETTE) |
| 218 | { |
| 219 | int shift_start[4], shift_dec[4]; |
Glenn Randers-Pehrson | d0dce40 | 1998-05-09 10:02:29 -0500 | [diff] [blame] | 220 | int channels = 0; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 221 | |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 222 | if (row_info->color_type & PNG_COLOR_MASK_COLOR) |
| 223 | { |
| 224 | shift_start[channels] = row_info->bit_depth - bit_depth->red; |
| 225 | shift_dec[channels] = bit_depth->red; |
| 226 | channels++; |
| 227 | shift_start[channels] = row_info->bit_depth - bit_depth->green; |
| 228 | shift_dec[channels] = bit_depth->green; |
| 229 | channels++; |
| 230 | shift_start[channels] = row_info->bit_depth - bit_depth->blue; |
| 231 | shift_dec[channels] = bit_depth->blue; |
| 232 | channels++; |
| 233 | } |
| 234 | else |
| 235 | { |
| 236 | shift_start[channels] = row_info->bit_depth - bit_depth->gray; |
| 237 | shift_dec[channels] = bit_depth->gray; |
| 238 | channels++; |
| 239 | } |
| 240 | if (row_info->color_type & PNG_COLOR_MASK_ALPHA) |
| 241 | { |
| 242 | shift_start[channels] = row_info->bit_depth - bit_depth->alpha; |
| 243 | shift_dec[channels] = bit_depth->alpha; |
| 244 | channels++; |
| 245 | } |
| 246 | |
Glenn Randers-Pehrson | 4bb4d01 | 2009-05-20 12:45:29 -0500 | [diff] [blame] | 247 | /* With low row depths, could only be grayscale, so one channel */ |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 248 | if (row_info->bit_depth < 8) |
| 249 | { |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 250 | png_bytep bp = row; |
| 251 | png_uint_32 i; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 252 | png_byte mask; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 253 | png_uint_32 row_bytes = row_info->rowbytes; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 254 | |
| 255 | if (bit_depth->gray == 1 && row_info->bit_depth == 2) |
| 256 | mask = 0x55; |
| 257 | else if (row_info->bit_depth == 4 && bit_depth->gray == 3) |
| 258 | mask = 0x11; |
| 259 | else |
| 260 | mask = 0xff; |
| 261 | |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 262 | for (i = 0; i < row_bytes; i++, bp++) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 263 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 264 | png_uint_16 v; |
| 265 | int j; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 266 | |
| 267 | v = *bp; |
| 268 | *bp = 0; |
| 269 | for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0]) |
| 270 | { |
| 271 | if (j > 0) |
| 272 | *bp |= (png_byte)((v << j) & 0xff); |
| 273 | else |
| 274 | *bp |= (png_byte)((v >> (-j)) & mask); |
| 275 | } |
| 276 | } |
| 277 | } |
| 278 | else if (row_info->bit_depth == 8) |
| 279 | { |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 280 | png_bytep bp = row; |
| 281 | png_uint_32 i; |
Glenn Randers-Pehrson | d0dce40 | 1998-05-09 10:02:29 -0500 | [diff] [blame] | 282 | png_uint_32 istop = channels * row_info->width; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 283 | |
Glenn Randers-Pehrson | d0dce40 | 1998-05-09 10:02:29 -0500 | [diff] [blame] | 284 | for (i = 0; i < istop; i++, bp++) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 285 | { |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 286 | |
Glenn Randers-Pehrson | d0dce40 | 1998-05-09 10:02:29 -0500 | [diff] [blame] | 287 | png_uint_16 v; |
| 288 | int j; |
| 289 | int c = (int)(i%channels); |
| 290 | |
| 291 | v = *bp; |
| 292 | *bp = 0; |
| 293 | for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c]) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 294 | { |
Glenn Randers-Pehrson | d0dce40 | 1998-05-09 10:02:29 -0500 | [diff] [blame] | 295 | if (j > 0) |
| 296 | *bp |= (png_byte)((v << j) & 0xff); |
| 297 | else |
| 298 | *bp |= (png_byte)((v >> (-j)) & 0xff); |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 299 | } |
| 300 | } |
| 301 | } |
| 302 | else |
| 303 | { |
Guy Schalnat | 6d76471 | 1995-12-19 03:22:19 -0600 | [diff] [blame] | 304 | png_bytep bp; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 305 | png_uint_32 i; |
Glenn Randers-Pehrson | d0dce40 | 1998-05-09 10:02:29 -0500 | [diff] [blame] | 306 | png_uint_32 istop = channels * row_info->width; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 307 | |
Glenn Randers-Pehrson | d0dce40 | 1998-05-09 10:02:29 -0500 | [diff] [blame] | 308 | for (bp = row, i = 0; i < istop; i++) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 309 | { |
Glenn Randers-Pehrson | d0dce40 | 1998-05-09 10:02:29 -0500 | [diff] [blame] | 310 | int c = (int)(i%channels); |
| 311 | png_uint_16 value, v; |
| 312 | int j; |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 313 | |
Glenn Randers-Pehrson | 860ab2b | 1999-10-14 07:43:10 -0500 | [diff] [blame] | 314 | v = (png_uint_16)(((png_uint_16)(*bp) << 8) + *(bp + 1)); |
Glenn Randers-Pehrson | d0dce40 | 1998-05-09 10:02:29 -0500 | [diff] [blame] | 315 | value = 0; |
| 316 | for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c]) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 317 | { |
Glenn Randers-Pehrson | d0dce40 | 1998-05-09 10:02:29 -0500 | [diff] [blame] | 318 | if (j > 0) |
| 319 | value |= (png_uint_16)((v << j) & (png_uint_16)0xffff); |
| 320 | else |
| 321 | value |= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff); |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 322 | } |
Glenn Randers-Pehrson | d0dce40 | 1998-05-09 10:02:29 -0500 | [diff] [blame] | 323 | *bp++ = (png_byte)(value >> 8); |
| 324 | *bp++ = (png_byte)(value & 0xff); |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 325 | } |
| 326 | } |
| 327 | } |
| 328 | } |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 329 | #endif |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 330 | |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 331 | #if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) |
Glenn Randers-Pehrson | 7529457 | 2000-05-06 14:09:57 -0500 | [diff] [blame] | 332 | void /* PRIVATE */ |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 333 | png_do_write_swap_alpha(png_row_infop row_info, png_bytep row) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 334 | { |
Glenn Randers-Pehrson | 51650b8 | 2008-08-05 07:44:42 -0500 | [diff] [blame] | 335 | png_debug(1, "in png_do_write_swap_alpha"); |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 336 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 337 | if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 338 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 339 | /* This converts from ARGB to RGBA */ |
| 340 | if (row_info->bit_depth == 8) |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 341 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 342 | png_bytep sp, dp; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 343 | png_uint_32 i; |
| 344 | png_uint_32 row_width = row_info->width; |
| 345 | for (i = 0, sp = dp = row; i < row_width; i++) |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 346 | { |
Glenn Randers-Pehrson | 896239b | 1998-04-21 15:03:57 -0500 | [diff] [blame] | 347 | png_byte save = *(sp++); |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 348 | *(dp++) = *(sp++); |
| 349 | *(dp++) = *(sp++); |
| 350 | *(dp++) = *(sp++); |
| 351 | *(dp++) = save; |
| 352 | } |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 353 | } |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 354 | /* This converts from AARRGGBB to RRGGBBAA */ |
| 355 | else |
| 356 | { |
| 357 | png_bytep sp, dp; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 358 | png_uint_32 i; |
| 359 | png_uint_32 row_width = row_info->width; |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 360 | |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 361 | for (i = 0, sp = dp = row; i < row_width; i++) |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 362 | { |
Glenn Randers-Pehrson | 896239b | 1998-04-21 15:03:57 -0500 | [diff] [blame] | 363 | png_byte save[2]; |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 364 | save[0] = *(sp++); |
| 365 | save[1] = *(sp++); |
| 366 | *(dp++) = *(sp++); |
| 367 | *(dp++) = *(sp++); |
| 368 | *(dp++) = *(sp++); |
| 369 | *(dp++) = *(sp++); |
| 370 | *(dp++) = *(sp++); |
| 371 | *(dp++) = *(sp++); |
| 372 | *(dp++) = save[0]; |
| 373 | *(dp++) = save[1]; |
| 374 | } |
| 375 | } |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 376 | } |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 377 | else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 378 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 379 | /* This converts from AG to GA */ |
| 380 | if (row_info->bit_depth == 8) |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 381 | { |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 382 | png_bytep sp, dp; |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 383 | png_uint_32 i; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 384 | png_uint_32 row_width = row_info->width; |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 385 | |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 386 | for (i = 0, sp = dp = row; i < row_width; i++) |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 387 | { |
Glenn Randers-Pehrson | 896239b | 1998-04-21 15:03:57 -0500 | [diff] [blame] | 388 | png_byte save = *(sp++); |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 389 | *(dp++) = *(sp++); |
| 390 | *(dp++) = save; |
| 391 | } |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 392 | } |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 393 | /* This converts from AAGG to GGAA */ |
| 394 | else |
| 395 | { |
| 396 | png_bytep sp, dp; |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 397 | png_uint_32 i; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 398 | png_uint_32 row_width = row_info->width; |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 399 | |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 400 | for (i = 0, sp = dp = row; i < row_width; i++) |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 401 | { |
Glenn Randers-Pehrson | 896239b | 1998-04-21 15:03:57 -0500 | [diff] [blame] | 402 | png_byte save[2]; |
Andreas Dilger | 47a0c42 | 1997-05-16 02:46:07 -0500 | [diff] [blame] | 403 | save[0] = *(sp++); |
| 404 | save[1] = *(sp++); |
| 405 | *(dp++) = *(sp++); |
| 406 | *(dp++) = *(sp++); |
| 407 | *(dp++) = save[0]; |
| 408 | *(dp++) = save[1]; |
| 409 | } |
| 410 | } |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 411 | } |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 412 | } |
| 413 | } |
Guy Schalnat | 51f0eb4 | 1995-09-26 05:22:39 -0500 | [diff] [blame] | 414 | #endif |
Guy Schalnat | 0d58058 | 1995-07-20 02:43:20 -0500 | [diff] [blame] | 415 | |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 416 | #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) |
Glenn Randers-Pehrson | 7529457 | 2000-05-06 14:09:57 -0500 | [diff] [blame] | 417 | void /* PRIVATE */ |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 418 | png_do_write_invert_alpha(png_row_infop row_info, png_bytep row) |
| 419 | { |
Glenn Randers-Pehrson | 51650b8 | 2008-08-05 07:44:42 -0500 | [diff] [blame] | 420 | png_debug(1, "in png_do_write_invert_alpha"); |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 421 | { |
| 422 | if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| 423 | { |
| 424 | /* This inverts the alpha channel in RGBA */ |
| 425 | if (row_info->bit_depth == 8) |
| 426 | { |
| 427 | png_bytep sp, dp; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 428 | png_uint_32 i; |
| 429 | png_uint_32 row_width = row_info->width; |
| 430 | for (i = 0, sp = dp = row; i < row_width; i++) |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 431 | { |
Glenn Randers-Pehrson | 4bb4d01 | 2009-05-20 12:45:29 -0500 | [diff] [blame] | 432 | /* Does nothing |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 433 | *(dp++) = *(sp++); |
| 434 | *(dp++) = *(sp++); |
| 435 | *(dp++) = *(sp++); |
Glenn Randers-Pehrson | 9c3ab68 | 2006-02-20 22:09:05 -0600 | [diff] [blame] | 436 | */ |
| 437 | sp+=3; dp = sp; |
Glenn Randers-Pehrson | 860ab2b | 1999-10-14 07:43:10 -0500 | [diff] [blame] | 438 | *(dp++) = (png_byte)(255 - *(sp++)); |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 439 | } |
| 440 | } |
| 441 | /* This inverts the alpha channel in RRGGBBAA */ |
| 442 | else |
| 443 | { |
| 444 | png_bytep sp, dp; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 445 | png_uint_32 i; |
| 446 | png_uint_32 row_width = row_info->width; |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 447 | |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 448 | for (i = 0, sp = dp = row; i < row_width; i++) |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 449 | { |
Glenn Randers-Pehrson | 4bb4d01 | 2009-05-20 12:45:29 -0500 | [diff] [blame] | 450 | /* Does nothing |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 451 | *(dp++) = *(sp++); |
| 452 | *(dp++) = *(sp++); |
| 453 | *(dp++) = *(sp++); |
| 454 | *(dp++) = *(sp++); |
| 455 | *(dp++) = *(sp++); |
| 456 | *(dp++) = *(sp++); |
Glenn Randers-Pehrson | 9c3ab68 | 2006-02-20 22:09:05 -0600 | [diff] [blame] | 457 | */ |
| 458 | sp+=6; dp = sp; |
Glenn Randers-Pehrson | 860ab2b | 1999-10-14 07:43:10 -0500 | [diff] [blame] | 459 | *(dp++) = (png_byte)(255 - *(sp++)); |
| 460 | *(dp++) = (png_byte)(255 - *(sp++)); |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 461 | } |
| 462 | } |
| 463 | } |
| 464 | else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) |
| 465 | { |
| 466 | /* This inverts the alpha channel in GA */ |
| 467 | if (row_info->bit_depth == 8) |
| 468 | { |
| 469 | png_bytep sp, dp; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 470 | png_uint_32 i; |
| 471 | png_uint_32 row_width = row_info->width; |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 472 | |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 473 | for (i = 0, sp = dp = row; i < row_width; i++) |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 474 | { |
| 475 | *(dp++) = *(sp++); |
Glenn Randers-Pehrson | 860ab2b | 1999-10-14 07:43:10 -0500 | [diff] [blame] | 476 | *(dp++) = (png_byte)(255 - *(sp++)); |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 477 | } |
| 478 | } |
| 479 | /* This inverts the alpha channel in GGAA */ |
| 480 | else |
| 481 | { |
| 482 | png_bytep sp, dp; |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 483 | png_uint_32 i; |
| 484 | png_uint_32 row_width = row_info->width; |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 485 | |
Glenn Randers-Pehrson | 1d96361 | 1998-05-02 12:52:25 -0500 | [diff] [blame] | 486 | for (i = 0, sp = dp = row; i < row_width; i++) |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 487 | { |
Glenn Randers-Pehrson | 4bb4d01 | 2009-05-20 12:45:29 -0500 | [diff] [blame] | 488 | /* Does nothing |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 489 | *(dp++) = *(sp++); |
| 490 | *(dp++) = *(sp++); |
Glenn Randers-Pehrson | 9c3ab68 | 2006-02-20 22:09:05 -0600 | [diff] [blame] | 491 | */ |
| 492 | sp+=2; dp = sp; |
Glenn Randers-Pehrson | 860ab2b | 1999-10-14 07:43:10 -0500 | [diff] [blame] | 493 | *(dp++) = (png_byte)(255 - *(sp++)); |
| 494 | *(dp++) = (png_byte)(255 - *(sp++)); |
Glenn Randers-Pehrson | c4a2ae6 | 1998-01-16 22:06:18 -0600 | [diff] [blame] | 495 | } |
| 496 | } |
| 497 | } |
| 498 | } |
| 499 | } |
| 500 | #endif |
Glenn Randers-Pehrson | 2ad31ae | 2000-12-15 08:54:42 -0600 | [diff] [blame] | 501 | |
| 502 | #if defined(PNG_MNG_FEATURES_SUPPORTED) |
Glenn Randers-Pehrson | 4bb4d01 | 2009-05-20 12:45:29 -0500 | [diff] [blame] | 503 | /* Undoes intrapixel differencing */ |
Glenn Randers-Pehrson | 2ad31ae | 2000-12-15 08:54:42 -0600 | [diff] [blame] | 504 | void /* PRIVATE */ |
| 505 | png_do_write_intrapixel(png_row_infop row_info, png_bytep row) |
| 506 | { |
Glenn Randers-Pehrson | 51650b8 | 2008-08-05 07:44:42 -0500 | [diff] [blame] | 507 | png_debug(1, "in png_do_write_intrapixel"); |
Glenn Randers-Pehrson | 2ad31ae | 2000-12-15 08:54:42 -0600 | [diff] [blame] | 508 | if ( |
Glenn Randers-Pehrson | 2ad31ae | 2000-12-15 08:54:42 -0600 | [diff] [blame] | 509 | (row_info->color_type & PNG_COLOR_MASK_COLOR)) |
| 510 | { |
| 511 | int bytes_per_pixel; |
| 512 | png_uint_32 row_width = row_info->width; |
| 513 | if (row_info->bit_depth == 8) |
| 514 | { |
| 515 | png_bytep rp; |
| 516 | png_uint_32 i; |
| 517 | |
| 518 | if (row_info->color_type == PNG_COLOR_TYPE_RGB) |
| 519 | bytes_per_pixel = 3; |
| 520 | else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| 521 | bytes_per_pixel = 4; |
| 522 | else |
| 523 | return; |
| 524 | |
| 525 | for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) |
| 526 | { |
| 527 | *(rp) = (png_byte)((*rp - *(rp+1))&0xff); |
| 528 | *(rp+2) = (png_byte)((*(rp+2) - *(rp+1))&0xff); |
| 529 | } |
| 530 | } |
| 531 | else if (row_info->bit_depth == 16) |
| 532 | { |
| 533 | png_bytep rp; |
| 534 | png_uint_32 i; |
| 535 | |
| 536 | if (row_info->color_type == PNG_COLOR_TYPE_RGB) |
| 537 | bytes_per_pixel = 6; |
| 538 | else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| 539 | bytes_per_pixel = 8; |
| 540 | else |
| 541 | return; |
| 542 | |
| 543 | for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) |
| 544 | { |
Glenn Randers-Pehrson | 5b5dcf8 | 2004-07-17 22:45:44 -0500 | [diff] [blame] | 545 | png_uint_32 s0 = (*(rp ) << 8) | *(rp+1); |
| 546 | png_uint_32 s1 = (*(rp+2) << 8) | *(rp+3); |
| 547 | png_uint_32 s2 = (*(rp+4) << 8) | *(rp+5); |
Glenn Randers-Pehrson | 145f5c8 | 2008-07-10 09:13:13 -0500 | [diff] [blame] | 548 | png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL); |
| 549 | png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL); |
Glenn Randers-Pehrson | 5b5dcf8 | 2004-07-17 22:45:44 -0500 | [diff] [blame] | 550 | *(rp ) = (png_byte)((red >> 8) & 0xff); |
| 551 | *(rp+1) = (png_byte)(red & 0xff); |
| 552 | *(rp+4) = (png_byte)((blue >> 8) & 0xff); |
| 553 | *(rp+5) = (png_byte)(blue & 0xff); |
Glenn Randers-Pehrson | 2ad31ae | 2000-12-15 08:54:42 -0600 | [diff] [blame] | 554 | } |
| 555 | } |
| 556 | } |
| 557 | } |
| 558 | #endif /* PNG_MNG_FEATURES_SUPPORTED */ |
Glenn Randers-Pehrson | 3097f61 | 2001-05-07 14:52:45 -0500 | [diff] [blame] | 559 | #endif /* PNG_WRITE_SUPPORTED */ |