| 1 | |
| 2 | /* pngwtran.c - transforms the data in a row for PNG writers |
| 3 | * |
| 4 | * libpng 1.0.3 - January 14, 1999 |
| 5 | * For conditions of distribution and use, see copyright notice in png.h |
| 6 | * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc. |
| 7 | * Copyright (c) 1996, 1997 Andreas Dilger |
| 8 | * Copyright (c) 1998, 1999 Glenn Randers-Pehrson |
| 9 | */ |
| 10 | |
| 11 | #define PNG_INTERNAL |
| 12 | #include "png.h" |
| 13 | |
| 14 | /* Transform the data according to the user's wishes. The order of |
| 15 | * transformations is significant. |
| 16 | */ |
| 17 | void |
| 18 | png_do_write_transformations(png_structp png_ptr) |
| 19 | { |
| 20 | png_debug(1, "in png_do_write_transformations\n"); |
| 21 | |
| 22 | #if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) |
| 23 | if (png_ptr->transformations & PNG_USER_TRANSFORM) |
| 24 | if(png_ptr->write_user_transform_fn != NULL) |
| 25 | (*(png_ptr->write_user_transform_fn)) /* user write transform function */ |
| 26 | (png_ptr, /* png_ptr */ |
| 27 | &(png_ptr->row_info), /* row_info: */ |
| 28 | /* png_uint_32 width; width of row */ |
| 29 | /* png_uint_32 rowbytes; number of bytes in row */ |
| 30 | /* png_byte color_type; color type of pixels */ |
| 31 | /* png_byte bit_depth; bit depth of samples */ |
| 32 | /* png_byte channels; number of channels (1-4) */ |
| 33 | /* png_byte pixel_depth; bits per pixel (depth*channels) */ |
| 34 | png_ptr->row_buf + 1); /* start of pixel data for row */ |
| 35 | #endif |
| 36 | #if defined(PNG_WRITE_FILLER_SUPPORTED) |
| 37 | if (png_ptr->transformations & PNG_FILLER) |
| 38 | png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| 39 | png_ptr->flags); |
| 40 | #endif |
| 41 | #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) |
| 42 | if (png_ptr->transformations & PNG_PACKSWAP) |
| 43 | png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| 44 | #endif |
| 45 | #if defined(PNG_WRITE_PACK_SUPPORTED) |
| 46 | if (png_ptr->transformations & PNG_PACK) |
| 47 | png_do_pack(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| 48 | (png_uint_32)png_ptr->bit_depth); |
| 49 | #endif |
| 50 | #if defined(PNG_WRITE_SWAP_SUPPORTED) |
| 51 | if (png_ptr->transformations & PNG_SWAP_BYTES) |
| 52 | png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| 53 | #endif |
| 54 | #if defined(PNG_WRITE_SHIFT_SUPPORTED) |
| 55 | if (png_ptr->transformations & PNG_SHIFT) |
| 56 | png_do_shift(&(png_ptr->row_info), png_ptr->row_buf + 1, |
| 57 | &(png_ptr->shift)); |
| 58 | #endif |
| 59 | #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) |
| 60 | if (png_ptr->transformations & PNG_INVERT_ALPHA) |
| 61 | png_do_write_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| 62 | #endif |
| 63 | #if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) |
| 64 | if (png_ptr->transformations & PNG_SWAP_ALPHA) |
| 65 | png_do_write_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| 66 | #endif |
| 67 | #if defined(PNG_WRITE_BGR_SUPPORTED) |
| 68 | if (png_ptr->transformations & PNG_BGR) |
| 69 | png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| 70 | #endif |
| 71 | #if defined(PNG_WRITE_INVERT_SUPPORTED) |
| 72 | if (png_ptr->transformations & PNG_INVERT_MONO) |
| 73 | png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1); |
| 74 | #endif |
| 75 | } |
| 76 | |
| 77 | #if defined(PNG_WRITE_PACK_SUPPORTED) |
| 78 | /* Pack pixels into bytes. Pass the true bit depth in bit_depth. The |
| 79 | * row_info bit depth should be 8 (one pixel per byte). The channels |
| 80 | * should be 1 (this only happens on grayscale and paletted images). |
| 81 | */ |
| 82 | void |
| 83 | png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth) |
| 84 | { |
| 85 | png_debug(1, "in png_do_pack\n"); |
| 86 | if (row_info->bit_depth == 8 && |
| 87 | #if defined(PNG_USELESS_TESTS_SUPPORTED) |
| 88 | row != NULL && row_info != NULL && |
| 89 | #endif |
| 90 | row_info->channels == 1) |
| 91 | { |
| 92 | switch ((int)bit_depth) |
| 93 | { |
| 94 | case 1: |
| 95 | { |
| 96 | png_bytep sp, dp; |
| 97 | int mask, v; |
| 98 | png_uint_32 i; |
| 99 | png_uint_32 row_width = row_info->width; |
| 100 | |
| 101 | sp = row; |
| 102 | dp = row; |
| 103 | mask = 0x80; |
| 104 | v = 0; |
| 105 | |
| 106 | for (i = 0; i < row_width; i++) |
| 107 | { |
| 108 | if (*sp != 0) |
| 109 | v |= mask; |
| 110 | sp++; |
| 111 | if (mask > 1) |
| 112 | mask >>= 1; |
| 113 | else |
| 114 | { |
| 115 | mask = 0x80; |
| 116 | *dp = (png_byte)v; |
| 117 | dp++; |
| 118 | v = 0; |
| 119 | } |
| 120 | } |
| 121 | if (mask != 0x80) |
| 122 | *dp = (png_byte)v; |
| 123 | break; |
| 124 | } |
| 125 | case 2: |
| 126 | { |
| 127 | png_bytep sp, dp; |
| 128 | int shift, v; |
| 129 | png_uint_32 i; |
| 130 | png_uint_32 row_width = row_info->width; |
| 131 | |
| 132 | sp = row; |
| 133 | dp = row; |
| 134 | shift = 6; |
| 135 | v = 0; |
| 136 | for (i = 0; i < row_width; i++) |
| 137 | { |
| 138 | png_byte value; |
| 139 | |
| 140 | value = (png_byte)(*sp & 0x3); |
| 141 | v |= (value << shift); |
| 142 | if (shift == 0) |
| 143 | { |
| 144 | shift = 6; |
| 145 | *dp = (png_byte)v; |
| 146 | dp++; |
| 147 | v = 0; |
| 148 | } |
| 149 | else |
| 150 | shift -= 2; |
| 151 | sp++; |
| 152 | } |
| 153 | if (shift != 6) |
| 154 | *dp = (png_byte)v; |
| 155 | break; |
| 156 | } |
| 157 | case 4: |
| 158 | { |
| 159 | png_bytep sp, dp; |
| 160 | int shift, v; |
| 161 | png_uint_32 i; |
| 162 | png_uint_32 row_width = row_info->width; |
| 163 | |
| 164 | sp = row; |
| 165 | dp = row; |
| 166 | shift = 4; |
| 167 | v = 0; |
| 168 | for (i = 0; i < row_width; i++) |
| 169 | { |
| 170 | png_byte value; |
| 171 | |
| 172 | value = (png_byte)(*sp & 0xf); |
| 173 | v |= (value << shift); |
| 174 | |
| 175 | if (shift == 0) |
| 176 | { |
| 177 | shift = 4; |
| 178 | *dp = (png_byte)v; |
| 179 | dp++; |
| 180 | v = 0; |
| 181 | } |
| 182 | else |
| 183 | shift -= 4; |
| 184 | |
| 185 | sp++; |
| 186 | } |
| 187 | if (shift != 4) |
| 188 | *dp = (png_byte)v; |
| 189 | break; |
| 190 | } |
| 191 | } |
| 192 | row_info->bit_depth = (png_byte)bit_depth; |
| 193 | row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels); |
| 194 | row_info->rowbytes = |
| 195 | ((row_info->width * row_info->pixel_depth + 7) >> 3); |
| 196 | } |
| 197 | } |
| 198 | #endif |
| 199 | |
| 200 | #if defined(PNG_WRITE_SHIFT_SUPPORTED) |
| 201 | /* Shift pixel values to take advantage of whole range. Pass the |
| 202 | * true number of bits in bit_depth. The row should be packed |
| 203 | * according to row_info->bit_depth. Thus, if you had a row of |
| 204 | * bit depth 4, but the pixels only had values from 0 to 7, you |
| 205 | * would pass 3 as bit_depth, and this routine would translate the |
| 206 | * data to 0 to 15. |
| 207 | */ |
| 208 | void |
| 209 | png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth) |
| 210 | { |
| 211 | png_debug(1, "in png_do_shift\n"); |
| 212 | #if defined(PNG_USELESS_TESTS_SUPPORTED) |
| 213 | if (row != NULL && row_info != NULL && |
| 214 | #else |
| 215 | if ( |
| 216 | #endif |
| 217 | row_info->color_type != PNG_COLOR_TYPE_PALETTE) |
| 218 | { |
| 219 | int shift_start[4], shift_dec[4]; |
| 220 | int channels = 0; |
| 221 | |
| 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 | |
| 247 | /* with low row depths, could only be grayscale, so one channel */ |
| 248 | if (row_info->bit_depth < 8) |
| 249 | { |
| 250 | png_bytep bp = row; |
| 251 | png_uint_32 i; |
| 252 | png_byte mask; |
| 253 | png_uint_32 row_bytes = row_info->rowbytes; |
| 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 | |
| 262 | for (i = 0; i < row_bytes; i++, bp++) |
| 263 | { |
| 264 | png_uint_16 v; |
| 265 | int j; |
| 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 | { |
| 280 | png_bytep bp = row; |
| 281 | png_uint_32 i; |
| 282 | png_uint_32 istop = channels * row_info->width; |
| 283 | |
| 284 | for (i = 0; i < istop; i++, bp++) |
| 285 | { |
| 286 | |
| 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]) |
| 294 | { |
| 295 | if (j > 0) |
| 296 | *bp |= (png_byte)((v << j) & 0xff); |
| 297 | else |
| 298 | *bp |= (png_byte)((v >> (-j)) & 0xff); |
| 299 | } |
| 300 | } |
| 301 | } |
| 302 | else |
| 303 | { |
| 304 | png_bytep bp; |
| 305 | png_uint_32 i; |
| 306 | png_uint_32 istop = channels * row_info->width; |
| 307 | |
| 308 | for (bp = row, i = 0; i < istop; i++) |
| 309 | { |
| 310 | int c = (int)(i%channels); |
| 311 | png_uint_16 value, v; |
| 312 | int j; |
| 313 | |
| 314 | v = ((png_uint_16)(*bp) << 8) + *(bp + 1); |
| 315 | value = 0; |
| 316 | for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c]) |
| 317 | { |
| 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); |
| 322 | } |
| 323 | *bp++ = (png_byte)(value >> 8); |
| 324 | *bp++ = (png_byte)(value & 0xff); |
| 325 | } |
| 326 | } |
| 327 | } |
| 328 | } |
| 329 | #endif |
| 330 | |
| 331 | #if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) |
| 332 | void |
| 333 | png_do_write_swap_alpha(png_row_infop row_info, png_bytep row) |
| 334 | { |
| 335 | png_debug(1, "in png_do_write_swap_alpha\n"); |
| 336 | #if defined(PNG_USELESS_TESTS_SUPPORTED) |
| 337 | if (row != NULL && row_info != NULL) |
| 338 | #endif |
| 339 | { |
| 340 | if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| 341 | { |
| 342 | /* This converts from ARGB to RGBA */ |
| 343 | if (row_info->bit_depth == 8) |
| 344 | { |
| 345 | png_bytep sp, dp; |
| 346 | png_uint_32 i; |
| 347 | png_uint_32 row_width = row_info->width; |
| 348 | for (i = 0, sp = dp = row; i < row_width; i++) |
| 349 | { |
| 350 | png_byte save = *(sp++); |
| 351 | *(dp++) = *(sp++); |
| 352 | *(dp++) = *(sp++); |
| 353 | *(dp++) = *(sp++); |
| 354 | *(dp++) = save; |
| 355 | } |
| 356 | } |
| 357 | /* This converts from AARRGGBB to RRGGBBAA */ |
| 358 | else |
| 359 | { |
| 360 | png_bytep sp, dp; |
| 361 | png_uint_32 i; |
| 362 | png_uint_32 row_width = row_info->width; |
| 363 | |
| 364 | for (i = 0, sp = dp = row; i < row_width; i++) |
| 365 | { |
| 366 | png_byte save[2]; |
| 367 | save[0] = *(sp++); |
| 368 | save[1] = *(sp++); |
| 369 | *(dp++) = *(sp++); |
| 370 | *(dp++) = *(sp++); |
| 371 | *(dp++) = *(sp++); |
| 372 | *(dp++) = *(sp++); |
| 373 | *(dp++) = *(sp++); |
| 374 | *(dp++) = *(sp++); |
| 375 | *(dp++) = save[0]; |
| 376 | *(dp++) = save[1]; |
| 377 | } |
| 378 | } |
| 379 | } |
| 380 | else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) |
| 381 | { |
| 382 | /* This converts from AG to GA */ |
| 383 | if (row_info->bit_depth == 8) |
| 384 | { |
| 385 | png_bytep sp, dp; |
| 386 | png_uint_32 i; |
| 387 | png_uint_32 row_width = row_info->width; |
| 388 | |
| 389 | for (i = 0, sp = dp = row; i < row_width; i++) |
| 390 | { |
| 391 | png_byte save = *(sp++); |
| 392 | *(dp++) = *(sp++); |
| 393 | *(dp++) = save; |
| 394 | } |
| 395 | } |
| 396 | /* This converts from AAGG to GGAA */ |
| 397 | else |
| 398 | { |
| 399 | png_bytep sp, dp; |
| 400 | png_uint_32 i; |
| 401 | png_uint_32 row_width = row_info->width; |
| 402 | |
| 403 | for (i = 0, sp = dp = row; i < row_width; i++) |
| 404 | { |
| 405 | png_byte save[2]; |
| 406 | save[0] = *(sp++); |
| 407 | save[1] = *(sp++); |
| 408 | *(dp++) = *(sp++); |
| 409 | *(dp++) = *(sp++); |
| 410 | *(dp++) = save[0]; |
| 411 | *(dp++) = save[1]; |
| 412 | } |
| 413 | } |
| 414 | } |
| 415 | } |
| 416 | } |
| 417 | #endif |
| 418 | |
| 419 | #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) |
| 420 | void |
| 421 | png_do_write_invert_alpha(png_row_infop row_info, png_bytep row) |
| 422 | { |
| 423 | png_debug(1, "in png_do_write_invert_alpha\n"); |
| 424 | #if defined(PNG_USELESS_TESTS_SUPPORTED) |
| 425 | if (row != NULL && row_info != NULL) |
| 426 | #endif |
| 427 | { |
| 428 | if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| 429 | { |
| 430 | /* This inverts the alpha channel in RGBA */ |
| 431 | if (row_info->bit_depth == 8) |
| 432 | { |
| 433 | png_bytep sp, dp; |
| 434 | png_uint_32 i; |
| 435 | png_uint_32 row_width = row_info->width; |
| 436 | for (i = 0, sp = dp = row; i < row_width; i++) |
| 437 | { |
| 438 | *(dp++) = *(sp++); |
| 439 | *(dp++) = *(sp++); |
| 440 | *(dp++) = *(sp++); |
| 441 | *(dp++) = 255 - *(sp++); |
| 442 | } |
| 443 | } |
| 444 | /* This inverts the alpha channel in RRGGBBAA */ |
| 445 | else |
| 446 | { |
| 447 | png_bytep sp, dp; |
| 448 | png_uint_32 i; |
| 449 | png_uint_32 row_width = row_info->width; |
| 450 | |
| 451 | for (i = 0, sp = dp = row; i < row_width; i++) |
| 452 | { |
| 453 | *(dp++) = *(sp++); |
| 454 | *(dp++) = *(sp++); |
| 455 | *(dp++) = *(sp++); |
| 456 | *(dp++) = *(sp++); |
| 457 | *(dp++) = *(sp++); |
| 458 | *(dp++) = *(sp++); |
| 459 | *(dp++) = 255 - *(sp++); |
| 460 | *(dp++) = 255 - *(sp++); |
| 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; |
| 470 | png_uint_32 i; |
| 471 | png_uint_32 row_width = row_info->width; |
| 472 | |
| 473 | for (i = 0, sp = dp = row; i < row_width; i++) |
| 474 | { |
| 475 | *(dp++) = *(sp++); |
| 476 | *(dp++) = 255 - *(sp++); |
| 477 | } |
| 478 | } |
| 479 | /* This inverts the alpha channel in GGAA */ |
| 480 | else |
| 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++) = *(sp++); |
| 490 | *(dp++) = 255 - *(sp++); |
| 491 | *(dp++) = 255 - *(sp++); |
| 492 | } |
| 493 | } |
| 494 | } |
| 495 | } |
| 496 | } |
| 497 | #endif |