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annotate libs/libpng/pngwtran.c @ 14:06dc8b9b4f89

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added libimago, libjpeg and libpng
author John Tsiombikas <nuclear@member.fsf.org>
date Sun, 07 Jun 2015 17:25:49 +0300
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children
rev   line source
nuclear@14 1
nuclear@14 2 /* pngwtran.c - transforms the data in a row for PNG writers
nuclear@14 3 *
nuclear@14 4 * Last changed in libpng 1.2.9 April 14, 2006
nuclear@14 5 * For conditions of distribution and use, see copyright notice in png.h
nuclear@14 6 * Copyright (c) 1998-2006 Glenn Randers-Pehrson
nuclear@14 7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
nuclear@14 8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
nuclear@14 9 */
nuclear@14 10
nuclear@14 11 #define PNG_INTERNAL
nuclear@14 12 #include "png.h"
nuclear@14 13 #ifdef PNG_WRITE_SUPPORTED
nuclear@14 14
nuclear@14 15 /* Transform the data according to the user's wishes. The order of
nuclear@14 16 * transformations is significant.
nuclear@14 17 */
nuclear@14 18 void /* PRIVATE */
nuclear@14 19 png_do_write_transformations(png_structp png_ptr)
nuclear@14 20 {
nuclear@14 21 png_debug(1, "in png_do_write_transformations\n");
nuclear@14 22
nuclear@14 23 if (png_ptr == NULL)
nuclear@14 24 return;
nuclear@14 25
nuclear@14 26 #if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
nuclear@14 27 if (png_ptr->transformations & PNG_USER_TRANSFORM)
nuclear@14 28 if (png_ptr->write_user_transform_fn != NULL)
nuclear@14 29 (*(png_ptr->write_user_transform_fn)) /* user write transform function */
nuclear@14 30 (png_ptr, /* png_ptr */
nuclear@14 31 &(png_ptr->row_info), /* row_info: */
nuclear@14 32 /* png_uint_32 width; width of row */
nuclear@14 33 /* png_uint_32 rowbytes; number of bytes in row */
nuclear@14 34 /* png_byte color_type; color type of pixels */
nuclear@14 35 /* png_byte bit_depth; bit depth of samples */
nuclear@14 36 /* png_byte channels; number of channels (1-4) */
nuclear@14 37 /* png_byte pixel_depth; bits per pixel (depth*channels) */
nuclear@14 38 png_ptr->row_buf + 1); /* start of pixel data for row */
nuclear@14 39 #endif
nuclear@14 40 #if defined(PNG_WRITE_FILLER_SUPPORTED)
nuclear@14 41 if (png_ptr->transformations & PNG_FILLER)
nuclear@14 42 png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
nuclear@14 43 png_ptr->flags);
nuclear@14 44 #endif
nuclear@14 45 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED)
nuclear@14 46 if (png_ptr->transformations & PNG_PACKSWAP)
nuclear@14 47 png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
nuclear@14 48 #endif
nuclear@14 49 #if defined(PNG_WRITE_PACK_SUPPORTED)
nuclear@14 50 if (png_ptr->transformations & PNG_PACK)
nuclear@14 51 png_do_pack(&(png_ptr->row_info), png_ptr->row_buf + 1,
nuclear@14 52 (png_uint_32)png_ptr->bit_depth);
nuclear@14 53 #endif
nuclear@14 54 #if defined(PNG_WRITE_SWAP_SUPPORTED)
nuclear@14 55 if (png_ptr->transformations & PNG_SWAP_BYTES)
nuclear@14 56 png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
nuclear@14 57 #endif
nuclear@14 58 #if defined(PNG_WRITE_SHIFT_SUPPORTED)
nuclear@14 59 if (png_ptr->transformations & PNG_SHIFT)
nuclear@14 60 png_do_shift(&(png_ptr->row_info), png_ptr->row_buf + 1,
nuclear@14 61 &(png_ptr->shift));
nuclear@14 62 #endif
nuclear@14 63 #if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
nuclear@14 64 if (png_ptr->transformations & PNG_SWAP_ALPHA)
nuclear@14 65 png_do_write_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
nuclear@14 66 #endif
nuclear@14 67 #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
nuclear@14 68 if (png_ptr->transformations & PNG_INVERT_ALPHA)
nuclear@14 69 png_do_write_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
nuclear@14 70 #endif
nuclear@14 71 #if defined(PNG_WRITE_BGR_SUPPORTED)
nuclear@14 72 if (png_ptr->transformations & PNG_BGR)
nuclear@14 73 png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
nuclear@14 74 #endif
nuclear@14 75 #if defined(PNG_WRITE_INVERT_SUPPORTED)
nuclear@14 76 if (png_ptr->transformations & PNG_INVERT_MONO)
nuclear@14 77 png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
nuclear@14 78 #endif
nuclear@14 79 }
nuclear@14 80
nuclear@14 81 #if defined(PNG_WRITE_PACK_SUPPORTED)
nuclear@14 82 /* Pack pixels into bytes. Pass the true bit depth in bit_depth. The
nuclear@14 83 * row_info bit depth should be 8 (one pixel per byte). The channels
nuclear@14 84 * should be 1 (this only happens on grayscale and paletted images).
nuclear@14 85 */
nuclear@14 86 void /* PRIVATE */
nuclear@14 87 png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
nuclear@14 88 {
nuclear@14 89 png_debug(1, "in png_do_pack\n");
nuclear@14 90 if (row_info->bit_depth == 8 &&
nuclear@14 91 #if defined(PNG_USELESS_TESTS_SUPPORTED)
nuclear@14 92 row != NULL && row_info != NULL &&
nuclear@14 93 #endif
nuclear@14 94 row_info->channels == 1)
nuclear@14 95 {
nuclear@14 96 switch ((int)bit_depth)
nuclear@14 97 {
nuclear@14 98 case 1:
nuclear@14 99 {
nuclear@14 100 png_bytep sp, dp;
nuclear@14 101 int mask, v;
nuclear@14 102 png_uint_32 i;
nuclear@14 103 png_uint_32 row_width = row_info->width;
nuclear@14 104
nuclear@14 105 sp = row;
nuclear@14 106 dp = row;
nuclear@14 107 mask = 0x80;
nuclear@14 108 v = 0;
nuclear@14 109
nuclear@14 110 for (i = 0; i < row_width; i++)
nuclear@14 111 {
nuclear@14 112 if (*sp != 0)
nuclear@14 113 v |= mask;
nuclear@14 114 sp++;
nuclear@14 115 if (mask > 1)
nuclear@14 116 mask >>= 1;
nuclear@14 117 else
nuclear@14 118 {
nuclear@14 119 mask = 0x80;
nuclear@14 120 *dp = (png_byte)v;
nuclear@14 121 dp++;
nuclear@14 122 v = 0;
nuclear@14 123 }
nuclear@14 124 }
nuclear@14 125 if (mask != 0x80)
nuclear@14 126 *dp = (png_byte)v;
nuclear@14 127 break;
nuclear@14 128 }
nuclear@14 129 case 2:
nuclear@14 130 {
nuclear@14 131 png_bytep sp, dp;
nuclear@14 132 int shift, v;
nuclear@14 133 png_uint_32 i;
nuclear@14 134 png_uint_32 row_width = row_info->width;
nuclear@14 135
nuclear@14 136 sp = row;
nuclear@14 137 dp = row;
nuclear@14 138 shift = 6;
nuclear@14 139 v = 0;
nuclear@14 140 for (i = 0; i < row_width; i++)
nuclear@14 141 {
nuclear@14 142 png_byte value;
nuclear@14 143
nuclear@14 144 value = (png_byte)(*sp & 0x03);
nuclear@14 145 v |= (value << shift);
nuclear@14 146 if (shift == 0)
nuclear@14 147 {
nuclear@14 148 shift = 6;
nuclear@14 149 *dp = (png_byte)v;
nuclear@14 150 dp++;
nuclear@14 151 v = 0;
nuclear@14 152 }
nuclear@14 153 else
nuclear@14 154 shift -= 2;
nuclear@14 155 sp++;
nuclear@14 156 }
nuclear@14 157 if (shift != 6)
nuclear@14 158 *dp = (png_byte)v;
nuclear@14 159 break;
nuclear@14 160 }
nuclear@14 161 case 4:
nuclear@14 162 {
nuclear@14 163 png_bytep sp, dp;
nuclear@14 164 int shift, v;
nuclear@14 165 png_uint_32 i;
nuclear@14 166 png_uint_32 row_width = row_info->width;
nuclear@14 167
nuclear@14 168 sp = row;
nuclear@14 169 dp = row;
nuclear@14 170 shift = 4;
nuclear@14 171 v = 0;
nuclear@14 172 for (i = 0; i < row_width; i++)
nuclear@14 173 {
nuclear@14 174 png_byte value;
nuclear@14 175
nuclear@14 176 value = (png_byte)(*sp & 0x0f);
nuclear@14 177 v |= (value << shift);
nuclear@14 178
nuclear@14 179 if (shift == 0)
nuclear@14 180 {
nuclear@14 181 shift = 4;
nuclear@14 182 *dp = (png_byte)v;
nuclear@14 183 dp++;
nuclear@14 184 v = 0;
nuclear@14 185 }
nuclear@14 186 else
nuclear@14 187 shift -= 4;
nuclear@14 188
nuclear@14 189 sp++;
nuclear@14 190 }
nuclear@14 191 if (shift != 4)
nuclear@14 192 *dp = (png_byte)v;
nuclear@14 193 break;
nuclear@14 194 }
nuclear@14 195 }
nuclear@14 196 row_info->bit_depth = (png_byte)bit_depth;
nuclear@14 197 row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
nuclear@14 198 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
nuclear@14 199 row_info->width);
nuclear@14 200 }
nuclear@14 201 }
nuclear@14 202 #endif
nuclear@14 203
nuclear@14 204 #if defined(PNG_WRITE_SHIFT_SUPPORTED)
nuclear@14 205 /* Shift pixel values to take advantage of whole range. Pass the
nuclear@14 206 * true number of bits in bit_depth. The row should be packed
nuclear@14 207 * according to row_info->bit_depth. Thus, if you had a row of
nuclear@14 208 * bit depth 4, but the pixels only had values from 0 to 7, you
nuclear@14 209 * would pass 3 as bit_depth, and this routine would translate the
nuclear@14 210 * data to 0 to 15.
nuclear@14 211 */
nuclear@14 212 void /* PRIVATE */
nuclear@14 213 png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
nuclear@14 214 {
nuclear@14 215 png_debug(1, "in png_do_shift\n");
nuclear@14 216 #if defined(PNG_USELESS_TESTS_SUPPORTED)
nuclear@14 217 if (row != NULL && row_info != NULL &&
nuclear@14 218 #else
nuclear@14 219 if (
nuclear@14 220 #endif
nuclear@14 221 row_info->color_type != PNG_COLOR_TYPE_PALETTE)
nuclear@14 222 {
nuclear@14 223 int shift_start[4], shift_dec[4];
nuclear@14 224 int channels = 0;
nuclear@14 225
nuclear@14 226 if (row_info->color_type & PNG_COLOR_MASK_COLOR)
nuclear@14 227 {
nuclear@14 228 shift_start[channels] = row_info->bit_depth - bit_depth->red;
nuclear@14 229 shift_dec[channels] = bit_depth->red;
nuclear@14 230 channels++;
nuclear@14 231 shift_start[channels] = row_info->bit_depth - bit_depth->green;
nuclear@14 232 shift_dec[channels] = bit_depth->green;
nuclear@14 233 channels++;
nuclear@14 234 shift_start[channels] = row_info->bit_depth - bit_depth->blue;
nuclear@14 235 shift_dec[channels] = bit_depth->blue;
nuclear@14 236 channels++;
nuclear@14 237 }
nuclear@14 238 else
nuclear@14 239 {
nuclear@14 240 shift_start[channels] = row_info->bit_depth - bit_depth->gray;
nuclear@14 241 shift_dec[channels] = bit_depth->gray;
nuclear@14 242 channels++;
nuclear@14 243 }
nuclear@14 244 if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
nuclear@14 245 {
nuclear@14 246 shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
nuclear@14 247 shift_dec[channels] = bit_depth->alpha;
nuclear@14 248 channels++;
nuclear@14 249 }
nuclear@14 250
nuclear@14 251 /* with low row depths, could only be grayscale, so one channel */
nuclear@14 252 if (row_info->bit_depth < 8)
nuclear@14 253 {
nuclear@14 254 png_bytep bp = row;
nuclear@14 255 png_uint_32 i;
nuclear@14 256 png_byte mask;
nuclear@14 257 png_uint_32 row_bytes = row_info->rowbytes;
nuclear@14 258
nuclear@14 259 if (bit_depth->gray == 1 && row_info->bit_depth == 2)
nuclear@14 260 mask = 0x55;
nuclear@14 261 else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
nuclear@14 262 mask = 0x11;
nuclear@14 263 else
nuclear@14 264 mask = 0xff;
nuclear@14 265
nuclear@14 266 for (i = 0; i < row_bytes; i++, bp++)
nuclear@14 267 {
nuclear@14 268 png_uint_16 v;
nuclear@14 269 int j;
nuclear@14 270
nuclear@14 271 v = *bp;
nuclear@14 272 *bp = 0;
nuclear@14 273 for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
nuclear@14 274 {
nuclear@14 275 if (j > 0)
nuclear@14 276 *bp |= (png_byte)((v << j) & 0xff);
nuclear@14 277 else
nuclear@14 278 *bp |= (png_byte)((v >> (-j)) & mask);
nuclear@14 279 }
nuclear@14 280 }
nuclear@14 281 }
nuclear@14 282 else if (row_info->bit_depth == 8)
nuclear@14 283 {
nuclear@14 284 png_bytep bp = row;
nuclear@14 285 png_uint_32 i;
nuclear@14 286 png_uint_32 istop = channels * row_info->width;
nuclear@14 287
nuclear@14 288 for (i = 0; i < istop; i++, bp++)
nuclear@14 289 {
nuclear@14 290
nuclear@14 291 png_uint_16 v;
nuclear@14 292 int j;
nuclear@14 293 int c = (int)(i%channels);
nuclear@14 294
nuclear@14 295 v = *bp;
nuclear@14 296 *bp = 0;
nuclear@14 297 for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
nuclear@14 298 {
nuclear@14 299 if (j > 0)
nuclear@14 300 *bp |= (png_byte)((v << j) & 0xff);
nuclear@14 301 else
nuclear@14 302 *bp |= (png_byte)((v >> (-j)) & 0xff);
nuclear@14 303 }
nuclear@14 304 }
nuclear@14 305 }
nuclear@14 306 else
nuclear@14 307 {
nuclear@14 308 png_bytep bp;
nuclear@14 309 png_uint_32 i;
nuclear@14 310 png_uint_32 istop = channels * row_info->width;
nuclear@14 311
nuclear@14 312 for (bp = row, i = 0; i < istop; i++)
nuclear@14 313 {
nuclear@14 314 int c = (int)(i%channels);
nuclear@14 315 png_uint_16 value, v;
nuclear@14 316 int j;
nuclear@14 317
nuclear@14 318 v = (png_uint_16)(((png_uint_16)(*bp) << 8) + *(bp + 1));
nuclear@14 319 value = 0;
nuclear@14 320 for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
nuclear@14 321 {
nuclear@14 322 if (j > 0)
nuclear@14 323 value |= (png_uint_16)((v << j) & (png_uint_16)0xffff);
nuclear@14 324 else
nuclear@14 325 value |= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff);
nuclear@14 326 }
nuclear@14 327 *bp++ = (png_byte)(value >> 8);
nuclear@14 328 *bp++ = (png_byte)(value & 0xff);
nuclear@14 329 }
nuclear@14 330 }
nuclear@14 331 }
nuclear@14 332 }
nuclear@14 333 #endif
nuclear@14 334
nuclear@14 335 #if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
nuclear@14 336 void /* PRIVATE */
nuclear@14 337 png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
nuclear@14 338 {
nuclear@14 339 png_debug(1, "in png_do_write_swap_alpha\n");
nuclear@14 340 #if defined(PNG_USELESS_TESTS_SUPPORTED)
nuclear@14 341 if (row != NULL && row_info != NULL)
nuclear@14 342 #endif
nuclear@14 343 {
nuclear@14 344 if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
nuclear@14 345 {
nuclear@14 346 /* This converts from ARGB to RGBA */
nuclear@14 347 if (row_info->bit_depth == 8)
nuclear@14 348 {
nuclear@14 349 png_bytep sp, dp;
nuclear@14 350 png_uint_32 i;
nuclear@14 351 png_uint_32 row_width = row_info->width;
nuclear@14 352 for (i = 0, sp = dp = row; i < row_width; i++)
nuclear@14 353 {
nuclear@14 354 png_byte save = *(sp++);
nuclear@14 355 *(dp++) = *(sp++);
nuclear@14 356 *(dp++) = *(sp++);
nuclear@14 357 *(dp++) = *(sp++);
nuclear@14 358 *(dp++) = save;
nuclear@14 359 }
nuclear@14 360 }
nuclear@14 361 /* This converts from AARRGGBB to RRGGBBAA */
nuclear@14 362 else
nuclear@14 363 {
nuclear@14 364 png_bytep sp, dp;
nuclear@14 365 png_uint_32 i;
nuclear@14 366 png_uint_32 row_width = row_info->width;
nuclear@14 367
nuclear@14 368 for (i = 0, sp = dp = row; i < row_width; i++)
nuclear@14 369 {
nuclear@14 370 png_byte save[2];
nuclear@14 371 save[0] = *(sp++);
nuclear@14 372 save[1] = *(sp++);
nuclear@14 373 *(dp++) = *(sp++);
nuclear@14 374 *(dp++) = *(sp++);
nuclear@14 375 *(dp++) = *(sp++);
nuclear@14 376 *(dp++) = *(sp++);
nuclear@14 377 *(dp++) = *(sp++);
nuclear@14 378 *(dp++) = *(sp++);
nuclear@14 379 *(dp++) = save[0];
nuclear@14 380 *(dp++) = save[1];
nuclear@14 381 }
nuclear@14 382 }
nuclear@14 383 }
nuclear@14 384 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
nuclear@14 385 {
nuclear@14 386 /* This converts from AG to GA */
nuclear@14 387 if (row_info->bit_depth == 8)
nuclear@14 388 {
nuclear@14 389 png_bytep sp, dp;
nuclear@14 390 png_uint_32 i;
nuclear@14 391 png_uint_32 row_width = row_info->width;
nuclear@14 392
nuclear@14 393 for (i = 0, sp = dp = row; i < row_width; i++)
nuclear@14 394 {
nuclear@14 395 png_byte save = *(sp++);
nuclear@14 396 *(dp++) = *(sp++);
nuclear@14 397 *(dp++) = save;
nuclear@14 398 }
nuclear@14 399 }
nuclear@14 400 /* This converts from AAGG to GGAA */
nuclear@14 401 else
nuclear@14 402 {
nuclear@14 403 png_bytep sp, dp;
nuclear@14 404 png_uint_32 i;
nuclear@14 405 png_uint_32 row_width = row_info->width;
nuclear@14 406
nuclear@14 407 for (i = 0, sp = dp = row; i < row_width; i++)
nuclear@14 408 {
nuclear@14 409 png_byte save[2];
nuclear@14 410 save[0] = *(sp++);
nuclear@14 411 save[1] = *(sp++);
nuclear@14 412 *(dp++) = *(sp++);
nuclear@14 413 *(dp++) = *(sp++);
nuclear@14 414 *(dp++) = save[0];
nuclear@14 415 *(dp++) = save[1];
nuclear@14 416 }
nuclear@14 417 }
nuclear@14 418 }
nuclear@14 419 }
nuclear@14 420 }
nuclear@14 421 #endif
nuclear@14 422
nuclear@14 423 #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
nuclear@14 424 void /* PRIVATE */
nuclear@14 425 png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
nuclear@14 426 {
nuclear@14 427 png_debug(1, "in png_do_write_invert_alpha\n");
nuclear@14 428 #if defined(PNG_USELESS_TESTS_SUPPORTED)
nuclear@14 429 if (row != NULL && row_info != NULL)
nuclear@14 430 #endif
nuclear@14 431 {
nuclear@14 432 if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
nuclear@14 433 {
nuclear@14 434 /* This inverts the alpha channel in RGBA */
nuclear@14 435 if (row_info->bit_depth == 8)
nuclear@14 436 {
nuclear@14 437 png_bytep sp, dp;
nuclear@14 438 png_uint_32 i;
nuclear@14 439 png_uint_32 row_width = row_info->width;
nuclear@14 440 for (i = 0, sp = dp = row; i < row_width; i++)
nuclear@14 441 {
nuclear@14 442 /* does nothing
nuclear@14 443 *(dp++) = *(sp++);
nuclear@14 444 *(dp++) = *(sp++);
nuclear@14 445 *(dp++) = *(sp++);
nuclear@14 446 */
nuclear@14 447 sp+=3; dp = sp;
nuclear@14 448 *(dp++) = (png_byte)(255 - *(sp++));
nuclear@14 449 }
nuclear@14 450 }
nuclear@14 451 /* This inverts the alpha channel in RRGGBBAA */
nuclear@14 452 else
nuclear@14 453 {
nuclear@14 454 png_bytep sp, dp;
nuclear@14 455 png_uint_32 i;
nuclear@14 456 png_uint_32 row_width = row_info->width;
nuclear@14 457
nuclear@14 458 for (i = 0, sp = dp = row; i < row_width; i++)
nuclear@14 459 {
nuclear@14 460 /* does nothing
nuclear@14 461 *(dp++) = *(sp++);
nuclear@14 462 *(dp++) = *(sp++);
nuclear@14 463 *(dp++) = *(sp++);
nuclear@14 464 *(dp++) = *(sp++);
nuclear@14 465 *(dp++) = *(sp++);
nuclear@14 466 *(dp++) = *(sp++);
nuclear@14 467 */
nuclear@14 468 sp+=6; dp = sp;
nuclear@14 469 *(dp++) = (png_byte)(255 - *(sp++));
nuclear@14 470 *(dp++) = (png_byte)(255 - *(sp++));
nuclear@14 471 }
nuclear@14 472 }
nuclear@14 473 }
nuclear@14 474 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
nuclear@14 475 {
nuclear@14 476 /* This inverts the alpha channel in GA */
nuclear@14 477 if (row_info->bit_depth == 8)
nuclear@14 478 {
nuclear@14 479 png_bytep sp, dp;
nuclear@14 480 png_uint_32 i;
nuclear@14 481 png_uint_32 row_width = row_info->width;
nuclear@14 482
nuclear@14 483 for (i = 0, sp = dp = row; i < row_width; i++)
nuclear@14 484 {
nuclear@14 485 *(dp++) = *(sp++);
nuclear@14 486 *(dp++) = (png_byte)(255 - *(sp++));
nuclear@14 487 }
nuclear@14 488 }
nuclear@14 489 /* This inverts the alpha channel in GGAA */
nuclear@14 490 else
nuclear@14 491 {
nuclear@14 492 png_bytep sp, dp;
nuclear@14 493 png_uint_32 i;
nuclear@14 494 png_uint_32 row_width = row_info->width;
nuclear@14 495
nuclear@14 496 for (i = 0, sp = dp = row; i < row_width; i++)
nuclear@14 497 {
nuclear@14 498 /* does nothing
nuclear@14 499 *(dp++) = *(sp++);
nuclear@14 500 *(dp++) = *(sp++);
nuclear@14 501 */
nuclear@14 502 sp+=2; dp = sp;
nuclear@14 503 *(dp++) = (png_byte)(255 - *(sp++));
nuclear@14 504 *(dp++) = (png_byte)(255 - *(sp++));
nuclear@14 505 }
nuclear@14 506 }
nuclear@14 507 }
nuclear@14 508 }
nuclear@14 509 }
nuclear@14 510 #endif
nuclear@14 511
nuclear@14 512 #if defined(PNG_MNG_FEATURES_SUPPORTED)
nuclear@14 513 /* undoes intrapixel differencing */
nuclear@14 514 void /* PRIVATE */
nuclear@14 515 png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
nuclear@14 516 {
nuclear@14 517 png_debug(1, "in png_do_write_intrapixel\n");
nuclear@14 518 if (
nuclear@14 519 #if defined(PNG_USELESS_TESTS_SUPPORTED)
nuclear@14 520 row != NULL && row_info != NULL &&
nuclear@14 521 #endif
nuclear@14 522 (row_info->color_type & PNG_COLOR_MASK_COLOR))
nuclear@14 523 {
nuclear@14 524 int bytes_per_pixel;
nuclear@14 525 png_uint_32 row_width = row_info->width;
nuclear@14 526 if (row_info->bit_depth == 8)
nuclear@14 527 {
nuclear@14 528 png_bytep rp;
nuclear@14 529 png_uint_32 i;
nuclear@14 530
nuclear@14 531 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
nuclear@14 532 bytes_per_pixel = 3;
nuclear@14 533 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
nuclear@14 534 bytes_per_pixel = 4;
nuclear@14 535 else
nuclear@14 536 return;
nuclear@14 537
nuclear@14 538 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
nuclear@14 539 {
nuclear@14 540 *(rp) = (png_byte)((*rp - *(rp+1))&0xff);
nuclear@14 541 *(rp+2) = (png_byte)((*(rp+2) - *(rp+1))&0xff);
nuclear@14 542 }
nuclear@14 543 }
nuclear@14 544 else if (row_info->bit_depth == 16)
nuclear@14 545 {
nuclear@14 546 png_bytep rp;
nuclear@14 547 png_uint_32 i;
nuclear@14 548
nuclear@14 549 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
nuclear@14 550 bytes_per_pixel = 6;
nuclear@14 551 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
nuclear@14 552 bytes_per_pixel = 8;
nuclear@14 553 else
nuclear@14 554 return;
nuclear@14 555
nuclear@14 556 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
nuclear@14 557 {
nuclear@14 558 png_uint_32 s0 = (*(rp ) << 8) | *(rp+1);
nuclear@14 559 png_uint_32 s1 = (*(rp+2) << 8) | *(rp+3);
nuclear@14 560 png_uint_32 s2 = (*(rp+4) << 8) | *(rp+5);
nuclear@14 561 png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL);
nuclear@14 562 png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
nuclear@14 563 *(rp ) = (png_byte)((red >> 8) & 0xff);
nuclear@14 564 *(rp+1) = (png_byte)(red & 0xff);
nuclear@14 565 *(rp+4) = (png_byte)((blue >> 8) & 0xff);
nuclear@14 566 *(rp+5) = (png_byte)(blue & 0xff);
nuclear@14 567 }
nuclear@14 568 }
nuclear@14 569 }
nuclear@14 570 }
nuclear@14 571 #endif /* PNG_MNG_FEATURES_SUPPORTED */
nuclear@14 572 #endif /* PNG_WRITE_SUPPORTED */