The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1 | |
| 2 | /* pngwtran.c - transforms the data in a row for PNG writers |
| 3 | * |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame^] | 4 | * Last changed in libpng 1.2.37 [June 4, 2009] |
| 5 | * Copyright (c) 1998-2009 Glenn Randers-Pehrson |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [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.) |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame^] | 8 | * |
| 9 | * This code is released under the libpng license. |
| 10 | * For conditions of distribution and use, see the disclaimer |
| 11 | * and license in png.h |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 12 | */ |
| 13 | |
| 14 | #define PNG_INTERNAL |
| 15 | #include "png.h" |
| 16 | #ifdef PNG_WRITE_SUPPORTED |
| 17 | |
| 18 | /* Transform the data according to the user's wishes. The order of |
| 19 | * transformations is significant. |
| 20 | */ |
| 21 | void /* PRIVATE */ |
| 22 | png_do_write_transformations(png_structp png_ptr) |
| 23 | { |
The Android Open Source Project | 4215dd1 | 2009-03-09 11:52:12 -0700 | [diff] [blame] | 24 | png_debug(1, "in png_do_write_transformations"); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 25 | |
| 26 | if (png_ptr == NULL) |
| 27 | return; |
| 28 | |
| 29 | #if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) |
| 30 | if (png_ptr->transformations & PNG_USER_TRANSFORM) |
The Android Open Source Project | 4215dd1 | 2009-03-09 11:52:12 -0700 | [diff] [blame] | 31 | if (png_ptr->write_user_transform_fn != NULL) |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame^] | 32 | (*(png_ptr->write_user_transform_fn)) /* User write transform function */ |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [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 |
| 43 | #if defined(PNG_WRITE_FILLER_SUPPORTED) |
| 44 | if (png_ptr->transformations & PNG_FILLER) |
| 45 | png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| 46 | png_ptr->flags); |
| 47 | #endif |
| 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 |
| 52 | #if defined(PNG_WRITE_PACK_SUPPORTED) |
| 53 | if (png_ptr->transformations & PNG_PACK) |
| 54 | png_do_pack(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| 55 | (png_uint_32)png_ptr->bit_depth); |
| 56 | #endif |
| 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 |
| 61 | #if defined(PNG_WRITE_SHIFT_SUPPORTED) |
| 62 | if (png_ptr->transformations & PNG_SHIFT) |
| 63 | png_do_shift(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| 64 | &(png_ptr->shift)); |
| 65 | #endif |
| 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 |
| 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 |
| 74 | #if defined(PNG_WRITE_BGR_SUPPORTED) |
| 75 | if (png_ptr->transformations & PNG_BGR) |
| 76 | png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| 77 | #endif |
| 78 | #if defined(PNG_WRITE_INVERT_SUPPORTED) |
| 79 | if (png_ptr->transformations & PNG_INVERT_MONO) |
| 80 | png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| 81 | #endif |
| 82 | } |
| 83 | |
| 84 | #if defined(PNG_WRITE_PACK_SUPPORTED) |
| 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 | */ |
| 89 | void /* PRIVATE */ |
| 90 | png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth) |
| 91 | { |
The Android Open Source Project | 4215dd1 | 2009-03-09 11:52:12 -0700 | [diff] [blame] | 92 | png_debug(1, "in png_do_pack"); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 93 | if (row_info->bit_depth == 8 && |
| 94 | #if defined(PNG_USELESS_TESTS_SUPPORTED) |
| 95 | row != NULL && row_info != NULL && |
| 96 | #endif |
| 97 | row_info->channels == 1) |
| 98 | { |
| 99 | switch ((int)bit_depth) |
| 100 | { |
| 101 | case 1: |
| 102 | { |
| 103 | png_bytep sp, dp; |
| 104 | int mask, v; |
| 105 | png_uint_32 i; |
| 106 | png_uint_32 row_width = row_info->width; |
| 107 | |
| 108 | sp = row; |
| 109 | dp = row; |
| 110 | mask = 0x80; |
| 111 | v = 0; |
| 112 | |
| 113 | for (i = 0; i < row_width; i++) |
| 114 | { |
| 115 | if (*sp != 0) |
| 116 | v |= mask; |
| 117 | sp++; |
| 118 | if (mask > 1) |
| 119 | mask >>= 1; |
| 120 | else |
| 121 | { |
| 122 | mask = 0x80; |
| 123 | *dp = (png_byte)v; |
| 124 | dp++; |
| 125 | v = 0; |
| 126 | } |
| 127 | } |
| 128 | if (mask != 0x80) |
| 129 | *dp = (png_byte)v; |
| 130 | break; |
| 131 | } |
| 132 | case 2: |
| 133 | { |
| 134 | png_bytep sp, dp; |
| 135 | int shift, v; |
| 136 | png_uint_32 i; |
| 137 | png_uint_32 row_width = row_info->width; |
| 138 | |
| 139 | sp = row; |
| 140 | dp = row; |
| 141 | shift = 6; |
| 142 | v = 0; |
| 143 | for (i = 0; i < row_width; i++) |
| 144 | { |
| 145 | png_byte value; |
| 146 | |
| 147 | value = (png_byte)(*sp & 0x03); |
| 148 | v |= (value << shift); |
| 149 | if (shift == 0) |
| 150 | { |
| 151 | shift = 6; |
| 152 | *dp = (png_byte)v; |
| 153 | dp++; |
| 154 | v = 0; |
| 155 | } |
| 156 | else |
| 157 | shift -= 2; |
| 158 | sp++; |
| 159 | } |
| 160 | if (shift != 6) |
| 161 | *dp = (png_byte)v; |
| 162 | break; |
| 163 | } |
| 164 | case 4: |
| 165 | { |
| 166 | png_bytep sp, dp; |
| 167 | int shift, v; |
| 168 | png_uint_32 i; |
| 169 | png_uint_32 row_width = row_info->width; |
| 170 | |
| 171 | sp = row; |
| 172 | dp = row; |
| 173 | shift = 4; |
| 174 | v = 0; |
| 175 | for (i = 0; i < row_width; i++) |
| 176 | { |
| 177 | png_byte value; |
| 178 | |
| 179 | value = (png_byte)(*sp & 0x0f); |
| 180 | v |= (value << shift); |
| 181 | |
| 182 | if (shift == 0) |
| 183 | { |
| 184 | shift = 4; |
| 185 | *dp = (png_byte)v; |
| 186 | dp++; |
| 187 | v = 0; |
| 188 | } |
| 189 | else |
| 190 | shift -= 4; |
| 191 | |
| 192 | sp++; |
| 193 | } |
| 194 | if (shift != 4) |
| 195 | *dp = (png_byte)v; |
| 196 | break; |
| 197 | } |
| 198 | } |
| 199 | row_info->bit_depth = (png_byte)bit_depth; |
| 200 | row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels); |
| 201 | row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, |
| 202 | row_info->width); |
| 203 | } |
| 204 | } |
| 205 | #endif |
| 206 | |
| 207 | #if defined(PNG_WRITE_SHIFT_SUPPORTED) |
| 208 | /* Shift pixel values to take advantage of whole range. Pass the |
| 209 | * true number of bits in bit_depth. The row should be packed |
| 210 | * according to row_info->bit_depth. Thus, if you had a row of |
| 211 | * bit depth 4, but the pixels only had values from 0 to 7, you |
| 212 | * would pass 3 as bit_depth, and this routine would translate the |
| 213 | * data to 0 to 15. |
| 214 | */ |
| 215 | void /* PRIVATE */ |
| 216 | png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth) |
| 217 | { |
The Android Open Source Project | 4215dd1 | 2009-03-09 11:52:12 -0700 | [diff] [blame] | 218 | png_debug(1, "in png_do_shift"); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 219 | #if defined(PNG_USELESS_TESTS_SUPPORTED) |
| 220 | if (row != NULL && row_info != NULL && |
| 221 | #else |
| 222 | if ( |
| 223 | #endif |
| 224 | row_info->color_type != PNG_COLOR_TYPE_PALETTE) |
| 225 | { |
| 226 | int shift_start[4], shift_dec[4]; |
| 227 | int channels = 0; |
| 228 | |
| 229 | if (row_info->color_type & PNG_COLOR_MASK_COLOR) |
| 230 | { |
| 231 | shift_start[channels] = row_info->bit_depth - bit_depth->red; |
| 232 | shift_dec[channels] = bit_depth->red; |
| 233 | channels++; |
| 234 | shift_start[channels] = row_info->bit_depth - bit_depth->green; |
| 235 | shift_dec[channels] = bit_depth->green; |
| 236 | channels++; |
| 237 | shift_start[channels] = row_info->bit_depth - bit_depth->blue; |
| 238 | shift_dec[channels] = bit_depth->blue; |
| 239 | channels++; |
| 240 | } |
| 241 | else |
| 242 | { |
| 243 | shift_start[channels] = row_info->bit_depth - bit_depth->gray; |
| 244 | shift_dec[channels] = bit_depth->gray; |
| 245 | channels++; |
| 246 | } |
| 247 | if (row_info->color_type & PNG_COLOR_MASK_ALPHA) |
| 248 | { |
| 249 | shift_start[channels] = row_info->bit_depth - bit_depth->alpha; |
| 250 | shift_dec[channels] = bit_depth->alpha; |
| 251 | channels++; |
| 252 | } |
| 253 | |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame^] | 254 | /* With low row depths, could only be grayscale, so one channel */ |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 255 | if (row_info->bit_depth < 8) |
| 256 | { |
| 257 | png_bytep bp = row; |
| 258 | png_uint_32 i; |
| 259 | png_byte mask; |
| 260 | png_uint_32 row_bytes = row_info->rowbytes; |
| 261 | |
| 262 | if (bit_depth->gray == 1 && row_info->bit_depth == 2) |
| 263 | mask = 0x55; |
| 264 | else if (row_info->bit_depth == 4 && bit_depth->gray == 3) |
| 265 | mask = 0x11; |
| 266 | else |
| 267 | mask = 0xff; |
| 268 | |
| 269 | for (i = 0; i < row_bytes; i++, bp++) |
| 270 | { |
| 271 | png_uint_16 v; |
| 272 | int j; |
| 273 | |
| 274 | v = *bp; |
| 275 | *bp = 0; |
| 276 | for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0]) |
| 277 | { |
| 278 | if (j > 0) |
| 279 | *bp |= (png_byte)((v << j) & 0xff); |
| 280 | else |
| 281 | *bp |= (png_byte)((v >> (-j)) & mask); |
| 282 | } |
| 283 | } |
| 284 | } |
| 285 | else if (row_info->bit_depth == 8) |
| 286 | { |
| 287 | png_bytep bp = row; |
| 288 | png_uint_32 i; |
| 289 | png_uint_32 istop = channels * row_info->width; |
| 290 | |
| 291 | for (i = 0; i < istop; i++, bp++) |
| 292 | { |
| 293 | |
| 294 | png_uint_16 v; |
| 295 | int j; |
| 296 | int c = (int)(i%channels); |
| 297 | |
| 298 | v = *bp; |
| 299 | *bp = 0; |
| 300 | for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c]) |
| 301 | { |
| 302 | if (j > 0) |
| 303 | *bp |= (png_byte)((v << j) & 0xff); |
| 304 | else |
| 305 | *bp |= (png_byte)((v >> (-j)) & 0xff); |
| 306 | } |
| 307 | } |
| 308 | } |
| 309 | else |
| 310 | { |
| 311 | png_bytep bp; |
| 312 | png_uint_32 i; |
| 313 | png_uint_32 istop = channels * row_info->width; |
| 314 | |
| 315 | for (bp = row, i = 0; i < istop; i++) |
| 316 | { |
| 317 | int c = (int)(i%channels); |
| 318 | png_uint_16 value, v; |
| 319 | int j; |
| 320 | |
| 321 | v = (png_uint_16)(((png_uint_16)(*bp) << 8) + *(bp + 1)); |
| 322 | value = 0; |
| 323 | for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c]) |
| 324 | { |
| 325 | if (j > 0) |
| 326 | value |= (png_uint_16)((v << j) & (png_uint_16)0xffff); |
| 327 | else |
| 328 | value |= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff); |
| 329 | } |
| 330 | *bp++ = (png_byte)(value >> 8); |
| 331 | *bp++ = (png_byte)(value & 0xff); |
| 332 | } |
| 333 | } |
| 334 | } |
| 335 | } |
| 336 | #endif |
| 337 | |
| 338 | #if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) |
| 339 | void /* PRIVATE */ |
| 340 | png_do_write_swap_alpha(png_row_infop row_info, png_bytep row) |
| 341 | { |
The Android Open Source Project | 4215dd1 | 2009-03-09 11:52:12 -0700 | [diff] [blame] | 342 | png_debug(1, "in png_do_write_swap_alpha"); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 343 | #if defined(PNG_USELESS_TESTS_SUPPORTED) |
| 344 | if (row != NULL && row_info != NULL) |
| 345 | #endif |
| 346 | { |
| 347 | if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| 348 | { |
| 349 | /* This converts from ARGB to RGBA */ |
| 350 | if (row_info->bit_depth == 8) |
| 351 | { |
| 352 | png_bytep sp, dp; |
| 353 | png_uint_32 i; |
| 354 | png_uint_32 row_width = row_info->width; |
| 355 | for (i = 0, sp = dp = row; i < row_width; i++) |
| 356 | { |
| 357 | png_byte save = *(sp++); |
| 358 | *(dp++) = *(sp++); |
| 359 | *(dp++) = *(sp++); |
| 360 | *(dp++) = *(sp++); |
| 361 | *(dp++) = save; |
| 362 | } |
| 363 | } |
| 364 | /* This converts from AARRGGBB to RRGGBBAA */ |
| 365 | else |
| 366 | { |
| 367 | png_bytep sp, dp; |
| 368 | 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 | { |
The Android Open Source Project | 4215dd1 | 2009-03-09 11:52:12 -0700 | [diff] [blame] | 430 | png_debug(1, "in png_do_write_invert_alpha"); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 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 | { |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame^] | 445 | /* Does nothing |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 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 | { |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame^] | 463 | /* Does nothing |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 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 | { |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame^] | 501 | /* Does nothing |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 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) |
Patrick Scott | a0bb96c | 2009-07-22 11:50:02 -0400 | [diff] [blame^] | 516 | /* Undoes intrapixel differencing */ |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 517 | void /* PRIVATE */ |
| 518 | png_do_write_intrapixel(png_row_infop row_info, png_bytep row) |
| 519 | { |
The Android Open Source Project | 4215dd1 | 2009-03-09 11:52:12 -0700 | [diff] [blame] | 520 | png_debug(1, "in png_do_write_intrapixel"); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 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); |
The Android Open Source Project | 4215dd1 | 2009-03-09 11:52:12 -0700 | [diff] [blame] | 564 | png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL); |
| 565 | png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 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 */ |