1
2 /* pngrtran.c - transforms the data in a row for PNG readers
3 *
4 * Last changed in libpng 1.2.45 [July 7, 2011]
5 * Copyright (c) 1998-2011 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
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
12 *
13 * This file contains functions optionally called by an application
14 * in order to tell libpng how to handle data when reading a PNG.
15 * Transformations that are used in both reading and writing are
16 * in pngtrans.c.
17 */
18
19 #define PNG_INTERNAL
20 #define PNG_NO_PEDANTIC_WARNINGS
21 #include "png.h"
22 #ifdef PNG_READ_SUPPORTED
23
24 /* Set the action on getting a CRC error for an ancillary or critical chunk. */
25 void PNGAPI
png_set_crc_action(png_structp png_ptr,int crit_action,int ancil_action)26 png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action)
27 {
28 png_debug(1, "in png_set_crc_action");
29
30 if (png_ptr == NULL)
31 return;
32
33 /* Tell libpng how we react to CRC errors in critical chunks */
34 switch (crit_action)
35 {
36 case PNG_CRC_NO_CHANGE: /* Leave setting as is */
37 break;
38
39 case PNG_CRC_WARN_USE: /* Warn/use data */
40 png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
41 png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
42 break;
43
44 case PNG_CRC_QUIET_USE: /* Quiet/use data */
45 png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
46 png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
47 PNG_FLAG_CRC_CRITICAL_IGNORE;
48 break;
49
50 case PNG_CRC_WARN_DISCARD: /* Not a valid action for critical data */
51 png_warning(png_ptr,
52 "Can't discard critical data on CRC error.");
53 case PNG_CRC_ERROR_QUIT: /* Error/quit */
54
55 case PNG_CRC_DEFAULT:
56 default:
57 png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
58 break;
59 }
60
61 /* Tell libpng how we react to CRC errors in ancillary chunks */
62 switch (ancil_action)
63 {
64 case PNG_CRC_NO_CHANGE: /* Leave setting as is */
65 break;
66
67 case PNG_CRC_WARN_USE: /* Warn/use data */
68 png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
69 png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
70 break;
71
72 case PNG_CRC_QUIET_USE: /* Quiet/use data */
73 png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
74 png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
75 PNG_FLAG_CRC_ANCILLARY_NOWARN;
76 break;
77
78 case PNG_CRC_ERROR_QUIT: /* Error/quit */
79 png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
80 png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
81 break;
82
83 case PNG_CRC_WARN_DISCARD: /* Warn/discard data */
84
85 case PNG_CRC_DEFAULT:
86 default:
87 png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
88 break;
89 }
90 }
91
92 #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
93 defined(PNG_FLOATING_POINT_SUPPORTED)
94 /* Handle alpha and tRNS via a background color */
95 void PNGAPI
png_set_background(png_structp png_ptr,png_color_16p background_color,int background_gamma_code,int need_expand,double background_gamma)96 png_set_background(png_structp png_ptr,
97 png_color_16p background_color, int background_gamma_code,
98 int need_expand, double background_gamma)
99 {
100 png_debug(1, "in png_set_background");
101
102 if (png_ptr == NULL)
103 return;
104 if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
105 {
106 png_warning(png_ptr, "Application must supply a known background gamma");
107 return;
108 }
109
110 png_ptr->transformations |= PNG_BACKGROUND;
111 png_memcpy(&(png_ptr->background), background_color,
112 png_sizeof(png_color_16));
113 png_ptr->background_gamma = (float)background_gamma;
114 png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
115 png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0);
116 }
117 #endif
118
119 #ifdef PNG_READ_16_TO_8_SUPPORTED
120 /* Strip 16 bit depth files to 8 bit depth */
121 void PNGAPI
png_set_strip_16(png_structp png_ptr)122 png_set_strip_16(png_structp png_ptr)
123 {
124 png_debug(1, "in png_set_strip_16");
125
126 if (png_ptr == NULL)
127 return;
128 png_ptr->transformations |= PNG_16_TO_8;
129 }
130 #endif
131
132 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
133 void PNGAPI
png_set_strip_alpha(png_structp png_ptr)134 png_set_strip_alpha(png_structp png_ptr)
135 {
136 png_debug(1, "in png_set_strip_alpha");
137
138 if (png_ptr == NULL)
139 return;
140 png_ptr->flags |= PNG_FLAG_STRIP_ALPHA;
141 }
142 #endif
143
144 #ifdef PNG_READ_DITHER_SUPPORTED
145 /* Dither file to 8 bit. Supply a palette, the current number
146 * of elements in the palette, the maximum number of elements
147 * allowed, and a histogram if possible. If the current number
148 * of colors is greater then the maximum number, the palette will be
149 * modified to fit in the maximum number. "full_dither" indicates
150 * whether we need a dithering cube set up for RGB images, or if we
151 * simply are reducing the number of colors in a paletted image.
152 */
153
154 typedef struct png_dsort_struct
155 {
156 struct png_dsort_struct FAR * next;
157 png_byte left;
158 png_byte right;
159 } png_dsort;
160 typedef png_dsort FAR * png_dsortp;
161 typedef png_dsort FAR * FAR * png_dsortpp;
162
163 void PNGAPI
png_set_dither(png_structp png_ptr,png_colorp palette,int num_palette,int maximum_colors,png_uint_16p histogram,int full_dither)164 png_set_dither(png_structp png_ptr, png_colorp palette,
165 int num_palette, int maximum_colors, png_uint_16p histogram,
166 int full_dither)
167 {
168 png_debug(1, "in png_set_dither");
169
170 if (png_ptr == NULL)
171 return;
172 png_ptr->transformations |= PNG_DITHER;
173
174 if (!full_dither)
175 {
176 int i;
177
178 png_ptr->dither_index = (png_bytep)png_malloc(png_ptr,
179 (png_uint_32)(num_palette * png_sizeof(png_byte)));
180 for (i = 0; i < num_palette; i++)
181 png_ptr->dither_index[i] = (png_byte)i;
182 }
183
184 if (num_palette > maximum_colors)
185 {
186 if (histogram != NULL)
187 {
188 /* This is easy enough, just throw out the least used colors.
189 * Perhaps not the best solution, but good enough.
190 */
191
192 int i;
193
194 /* Initialize an array to sort colors */
195 png_ptr->dither_sort = (png_bytep)png_malloc(png_ptr,
196 (png_uint_32)(num_palette * png_sizeof(png_byte)));
197
198 /* Initialize the dither_sort array */
199 for (i = 0; i < num_palette; i++)
200 png_ptr->dither_sort[i] = (png_byte)i;
201
202 /* Find the least used palette entries by starting a
203 * bubble sort, and running it until we have sorted
204 * out enough colors. Note that we don't care about
205 * sorting all the colors, just finding which are
206 * least used.
207 */
208
209 for (i = num_palette - 1; i >= maximum_colors; i--)
210 {
211 int done; /* To stop early if the list is pre-sorted */
212 int j;
213
214 done = 1;
215 for (j = 0; j < i; j++)
216 {
217 if (histogram[png_ptr->dither_sort[j]]
218 < histogram[png_ptr->dither_sort[j + 1]])
219 {
220 png_byte t;
221
222 t = png_ptr->dither_sort[j];
223 png_ptr->dither_sort[j] = png_ptr->dither_sort[j + 1];
224 png_ptr->dither_sort[j + 1] = t;
225 done = 0;
226 }
227 }
228 if (done)
229 break;
230 }
231
232 /* Swap the palette around, and set up a table, if necessary */
233 if (full_dither)
234 {
235 int j = num_palette;
236
237 /* Put all the useful colors within the max, but don't
238 * move the others.
239 */
240 for (i = 0; i < maximum_colors; i++)
241 {
242 if ((int)png_ptr->dither_sort[i] >= maximum_colors)
243 {
244 do
245 j--;
246 while ((int)png_ptr->dither_sort[j] >= maximum_colors);
247 palette[i] = palette[j];
248 }
249 }
250 }
251 else
252 {
253 int j = num_palette;
254
255 /* Move all the used colors inside the max limit, and
256 * develop a translation table.
257 */
258 for (i = 0; i < maximum_colors; i++)
259 {
260 /* Only move the colors we need to */
261 if ((int)png_ptr->dither_sort[i] >= maximum_colors)
262 {
263 png_color tmp_color;
264
265 do
266 j--;
267 while ((int)png_ptr->dither_sort[j] >= maximum_colors);
268
269 tmp_color = palette[j];
270 palette[j] = palette[i];
271 palette[i] = tmp_color;
272 /* Indicate where the color went */
273 png_ptr->dither_index[j] = (png_byte)i;
274 png_ptr->dither_index[i] = (png_byte)j;
275 }
276 }
277
278 /* Find closest color for those colors we are not using */
279 for (i = 0; i < num_palette; i++)
280 {
281 if ((int)png_ptr->dither_index[i] >= maximum_colors)
282 {
283 int min_d, k, min_k, d_index;
284
285 /* Find the closest color to one we threw out */
286 d_index = png_ptr->dither_index[i];
287 min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
288 for (k = 1, min_k = 0; k < maximum_colors; k++)
289 {
290 int d;
291
292 d = PNG_COLOR_DIST(palette[d_index], palette[k]);
293
294 if (d < min_d)
295 {
296 min_d = d;
297 min_k = k;
298 }
299 }
300 /* Point to closest color */
301 png_ptr->dither_index[i] = (png_byte)min_k;
302 }
303 }
304 }
305 png_free(png_ptr, png_ptr->dither_sort);
306 png_ptr->dither_sort = NULL;
307 }
308 else
309 {
310 /* This is much harder to do simply (and quickly). Perhaps
311 * we need to go through a median cut routine, but those
312 * don't always behave themselves with only a few colors
313 * as input. So we will just find the closest two colors,
314 * and throw out one of them (chosen somewhat randomly).
315 * [We don't understand this at all, so if someone wants to
316 * work on improving it, be our guest - AED, GRP]
317 */
318 int i;
319 int max_d;
320 int num_new_palette;
321 png_dsortp t;
322 png_dsortpp hash;
323
324 t = NULL;
325
326 /* Initialize palette index arrays */
327 png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
328 (png_uint_32)(num_palette * png_sizeof(png_byte)));
329 png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
330 (png_uint_32)(num_palette * png_sizeof(png_byte)));
331
332 /* Initialize the sort array */
333 for (i = 0; i < num_palette; i++)
334 {
335 png_ptr->index_to_palette[i] = (png_byte)i;
336 png_ptr->palette_to_index[i] = (png_byte)i;
337 }
338
339 hash = (png_dsortpp)png_calloc(png_ptr, (png_uint_32)(769 *
340 png_sizeof(png_dsortp)));
341
342 num_new_palette = num_palette;
343
344 /* Initial wild guess at how far apart the farthest pixel
345 * pair we will be eliminating will be. Larger
346 * numbers mean more areas will be allocated, Smaller
347 * numbers run the risk of not saving enough data, and
348 * having to do this all over again.
349 *
350 * I have not done extensive checking on this number.
351 */
352 max_d = 96;
353
354 while (num_new_palette > maximum_colors)
355 {
356 for (i = 0; i < num_new_palette - 1; i++)
357 {
358 int j;
359
360 for (j = i + 1; j < num_new_palette; j++)
361 {
362 int d;
363
364 d = PNG_COLOR_DIST(palette[i], palette[j]);
365
366 if (d <= max_d)
367 {
368
369 t = (png_dsortp)png_malloc_warn(png_ptr,
370 (png_uint_32)(png_sizeof(png_dsort)));
371 if (t == NULL)
372 break;
373 t->next = hash[d];
374 t->left = (png_byte)i;
375 t->right = (png_byte)j;
376 hash[d] = t;
377 }
378 }
379 if (t == NULL)
380 break;
381 }
382
383 if (t != NULL)
384 for (i = 0; i <= max_d; i++)
385 {
386 if (hash[i] != NULL)
387 {
388 png_dsortp p;
389
390 for (p = hash[i]; p; p = p->next)
391 {
392 if ((int)png_ptr->index_to_palette[p->left]
393 < num_new_palette &&
394 (int)png_ptr->index_to_palette[p->right]
395 < num_new_palette)
396 {
397 int j, next_j;
398
399 if (num_new_palette & 0x01)
400 {
401 j = p->left;
402 next_j = p->right;
403 }
404 else
405 {
406 j = p->right;
407 next_j = p->left;
408 }
409
410 num_new_palette--;
411 palette[png_ptr->index_to_palette[j]]
412 = palette[num_new_palette];
413 if (!full_dither)
414 {
415 int k;
416
417 for (k = 0; k < num_palette; k++)
418 {
419 if (png_ptr->dither_index[k] ==
420 png_ptr->index_to_palette[j])
421 png_ptr->dither_index[k] =
422 png_ptr->index_to_palette[next_j];
423 if ((int)png_ptr->dither_index[k] ==
424 num_new_palette)
425 png_ptr->dither_index[k] =
426 png_ptr->index_to_palette[j];
427 }
428 }
429
430 png_ptr->index_to_palette[png_ptr->palette_to_index
431 [num_new_palette]] = png_ptr->index_to_palette[j];
432 png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
433 = png_ptr->palette_to_index[num_new_palette];
434
435 png_ptr->index_to_palette[j] =
436 (png_byte)num_new_palette;
437 png_ptr->palette_to_index[num_new_palette] =
438 (png_byte)j;
439 }
440 if (num_new_palette <= maximum_colors)
441 break;
442 }
443 if (num_new_palette <= maximum_colors)
444 break;
445 }
446 }
447
448 for (i = 0; i < 769; i++)
449 {
450 if (hash[i] != NULL)
451 {
452 png_dsortp p = hash[i];
453 while (p)
454 {
455 t = p->next;
456 png_free(png_ptr, p);
457 p = t;
458 }
459 }
460 hash[i] = 0;
461 }
462 max_d += 96;
463 }
464 png_free(png_ptr, hash);
465 png_free(png_ptr, png_ptr->palette_to_index);
466 png_free(png_ptr, png_ptr->index_to_palette);
467 png_ptr->palette_to_index = NULL;
468 png_ptr->index_to_palette = NULL;
469 }
470 num_palette = maximum_colors;
471 }
472 if (png_ptr->palette == NULL)
473 {
474 png_ptr->palette = palette;
475 }
476 png_ptr->num_palette = (png_uint_16)num_palette;
477
478 if (full_dither)
479 {
480 int i;
481 png_bytep distance;
482 int total_bits = PNG_DITHER_RED_BITS + PNG_DITHER_GREEN_BITS +
483 PNG_DITHER_BLUE_BITS;
484 int num_red = (1 << PNG_DITHER_RED_BITS);
485 int num_green = (1 << PNG_DITHER_GREEN_BITS);
486 int num_blue = (1 << PNG_DITHER_BLUE_BITS);
487 png_size_t num_entries = ((png_size_t)1 << total_bits);
488
489 png_ptr->palette_lookup = (png_bytep )png_calloc(png_ptr,
490 (png_uint_32)(num_entries * png_sizeof(png_byte)));
491
492 distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries *
493 png_sizeof(png_byte)));
494 png_memset(distance, 0xff, num_entries * png_sizeof(png_byte));
495
496 for (i = 0; i < num_palette; i++)
497 {
498 int ir, ig, ib;
499 int r = (palette[i].red >> (8 - PNG_DITHER_RED_BITS));
500 int g = (palette[i].green >> (8 - PNG_DITHER_GREEN_BITS));
501 int b = (palette[i].blue >> (8 - PNG_DITHER_BLUE_BITS));
502
503 for (ir = 0; ir < num_red; ir++)
504 {
505 /* int dr = abs(ir - r); */
506 int dr = ((ir > r) ? ir - r : r - ir);
507 int index_r = (ir << (PNG_DITHER_BLUE_BITS +
508 PNG_DITHER_GREEN_BITS));
509
510 for (ig = 0; ig < num_green; ig++)
511 {
512 /* int dg = abs(ig - g); */
513 int dg = ((ig > g) ? ig - g : g - ig);
514 int dt = dr + dg;
515 int dm = ((dr > dg) ? dr : dg);
516 int index_g = index_r | (ig << PNG_DITHER_BLUE_BITS);
517
518 for (ib = 0; ib < num_blue; ib++)
519 {
520 int d_index = index_g | ib;
521 /* int db = abs(ib - b); */
522 int db = ((ib > b) ? ib - b : b - ib);
523 int dmax = ((dm > db) ? dm : db);
524 int d = dmax + dt + db;
525
526 if (d < (int)distance[d_index])
527 {
528 distance[d_index] = (png_byte)d;
529 png_ptr->palette_lookup[d_index] = (png_byte)i;
530 }
531 }
532 }
533 }
534 }
535
536 png_free(png_ptr, distance);
537 }
538 }
539 #endif
540
541 #if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
542 /* Transform the image from the file_gamma to the screen_gamma. We
543 * only do transformations on images where the file_gamma and screen_gamma
544 * are not close reciprocals, otherwise it slows things down slightly, and
545 * also needlessly introduces small errors.
546 *
547 * We will turn off gamma transformation later if no semitransparent entries
548 * are present in the tRNS array for palette images. We can't do it here
549 * because we don't necessarily have the tRNS chunk yet.
550 */
551 void PNGAPI
png_set_gamma(png_structp png_ptr,double scrn_gamma,double file_gamma)552 png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
553 {
554 png_debug(1, "in png_set_gamma");
555
556 if (png_ptr == NULL)
557 return;
558
559 if ((fabs(scrn_gamma * file_gamma - 1.0) > PNG_GAMMA_THRESHOLD) ||
560 (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) ||
561 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
562 png_ptr->transformations |= PNG_GAMMA;
563 png_ptr->gamma = (float)file_gamma;
564 png_ptr->screen_gamma = (float)scrn_gamma;
565 }
566 #endif
567
568 #ifdef PNG_READ_EXPAND_SUPPORTED
569 /* Expand paletted images to RGB, expand grayscale images of
570 * less than 8-bit depth to 8-bit depth, and expand tRNS chunks
571 * to alpha channels.
572 */
573 void PNGAPI
png_set_expand(png_structp png_ptr)574 png_set_expand(png_structp png_ptr)
575 {
576 png_debug(1, "in png_set_expand");
577
578 if (png_ptr == NULL)
579 return;
580
581 png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
582 png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
583 }
584
585 /* GRR 19990627: the following three functions currently are identical
586 * to png_set_expand(). However, it is entirely reasonable that someone
587 * might wish to expand an indexed image to RGB but *not* expand a single,
588 * fully transparent palette entry to a full alpha channel--perhaps instead
589 * convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
590 * the transparent color with a particular RGB value, or drop tRNS entirely.
591 * IOW, a future version of the library may make the transformations flag
592 * a bit more fine-grained, with separate bits for each of these three
593 * functions.
594 *
595 * More to the point, these functions make it obvious what libpng will be
596 * doing, whereas "expand" can (and does) mean any number of things.
597 *
598 * GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified
599 * to expand only the sample depth but not to expand the tRNS to alpha
600 * and its name was changed to png_set_expand_gray_1_2_4_to_8().
601 */
602
603 /* Expand paletted images to RGB. */
604 void PNGAPI
png_set_palette_to_rgb(png_structp png_ptr)605 png_set_palette_to_rgb(png_structp png_ptr)
606 {
607 png_debug(1, "in png_set_palette_to_rgb");
608
609 if (png_ptr == NULL)
610 return;
611
612 png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
613 png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
614 }
615
616 #ifndef PNG_1_0_X
617 /* Expand grayscale images of less than 8-bit depth to 8 bits. */
618 void PNGAPI
png_set_expand_gray_1_2_4_to_8(png_structp png_ptr)619 png_set_expand_gray_1_2_4_to_8(png_structp png_ptr)
620 {
621 png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
622
623 if (png_ptr == NULL)
624 return;
625
626 png_ptr->transformations |= PNG_EXPAND;
627 png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
628 }
629 #endif
630
631 #if defined(PNG_1_0_X) || defined(PNG_1_2_X)
632 /* Expand grayscale images of less than 8-bit depth to 8 bits. */
633 /* Deprecated as of libpng-1.2.9 */
634 void PNGAPI
png_set_gray_1_2_4_to_8(png_structp png_ptr)635 png_set_gray_1_2_4_to_8(png_structp png_ptr)
636 {
637 png_debug(1, "in png_set_gray_1_2_4_to_8");
638
639 if (png_ptr == NULL)
640 return;
641
642 png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
643 }
644 #endif
645
646
647 /* Expand tRNS chunks to alpha channels. */
648 void PNGAPI
png_set_tRNS_to_alpha(png_structp png_ptr)649 png_set_tRNS_to_alpha(png_structp png_ptr)
650 {
651 png_debug(1, "in png_set_tRNS_to_alpha");
652
653 png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
654 png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
655 }
656 #endif /* defined(PNG_READ_EXPAND_SUPPORTED) */
657
658 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
659 void PNGAPI
png_set_gray_to_rgb(png_structp png_ptr)660 png_set_gray_to_rgb(png_structp png_ptr)
661 {
662 png_debug(1, "in png_set_gray_to_rgb");
663
664 png_ptr->transformations |= PNG_GRAY_TO_RGB;
665 png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
666 }
667 #endif
668
669 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
670 #ifdef PNG_FLOATING_POINT_SUPPORTED
671 /* Convert a RGB image to a grayscale of the same width. This allows us,
672 * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
673 */
674
675 void PNGAPI
png_set_rgb_to_gray(png_structp png_ptr,int error_action,double red,double green)676 png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red,
677 double green)
678 {
679 int red_fixed, green_fixed;
680 if (png_ptr == NULL)
681 return;
682 if (red > 21474.83647 || red < -21474.83648 ||
683 green > 21474.83647 || green < -21474.83648)
684 {
685 png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients");
686 red_fixed = -1;
687 green_fixed = -1;
688 }
689 else
690 {
691 red_fixed = (int)((float)red*100000.0 + 0.5);
692 green_fixed = (int)((float)green*100000.0 + 0.5);
693 }
694 png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed);
695 }
696 #endif
697
698 void PNGAPI
png_set_rgb_to_gray_fixed(png_structp png_ptr,int error_action,png_fixed_point red,png_fixed_point green)699 png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action,
700 png_fixed_point red, png_fixed_point green)
701 {
702 png_debug(1, "in png_set_rgb_to_gray");
703
704 if (png_ptr == NULL)
705 return;
706
707 switch(error_action)
708 {
709 case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY;
710 break;
711
712 case 2: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
713 break;
714
715 case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
716 }
717 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
718 #ifdef PNG_READ_EXPAND_SUPPORTED
719 png_ptr->transformations |= PNG_EXPAND;
720 #else
721 {
722 png_warning(png_ptr,
723 "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED.");
724 png_ptr->transformations &= ~PNG_RGB_TO_GRAY;
725 }
726 #endif
727 {
728 png_uint_16 red_int, green_int;
729 if (red < 0 || green < 0)
730 {
731 red_int = 6968; /* .212671 * 32768 + .5 */
732 green_int = 23434; /* .715160 * 32768 + .5 */
733 }
734 else if (red + green < 100000L)
735 {
736 red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L);
737 green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L);
738 }
739 else
740 {
741 png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients");
742 red_int = 6968;
743 green_int = 23434;
744 }
745 png_ptr->rgb_to_gray_red_coeff = red_int;
746 png_ptr->rgb_to_gray_green_coeff = green_int;
747 png_ptr->rgb_to_gray_blue_coeff =
748 (png_uint_16)(32768 - red_int - green_int);
749 }
750 }
751 #endif
752
753 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
754 defined(PNG_LEGACY_SUPPORTED) || \
755 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
756 void PNGAPI
png_set_read_user_transform_fn(png_structp png_ptr,png_user_transform_ptr read_user_transform_fn)757 png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
758 read_user_transform_fn)
759 {
760 png_debug(1, "in png_set_read_user_transform_fn");
761
762 if (png_ptr == NULL)
763 return;
764
765 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
766 png_ptr->transformations |= PNG_USER_TRANSFORM;
767 png_ptr->read_user_transform_fn = read_user_transform_fn;
768 #endif
769 #ifdef PNG_LEGACY_SUPPORTED
770 if (read_user_transform_fn)
771 png_warning(png_ptr,
772 "This version of libpng does not support user transforms");
773 #endif
774 }
775 #endif
776
777 /* Initialize everything needed for the read. This includes modifying
778 * the palette.
779 */
780 void /* PRIVATE */
png_init_read_transformations(png_structp png_ptr)781 png_init_read_transformations(png_structp png_ptr)
782 {
783 png_debug(1, "in png_init_read_transformations");
784
785 #ifdef PNG_USELESS_TESTS_SUPPORTED
786 if (png_ptr != NULL)
787 #endif
788 {
789 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
790 defined(PNG_READ_SHIFT_SUPPORTED) || \
791 defined(PNG_READ_GAMMA_SUPPORTED)
792 int color_type = png_ptr->color_type;
793 #endif
794
795 #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
796
797 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
798 /* Detect gray background and attempt to enable optimization
799 * for gray --> RGB case
800 *
801 * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
802 * RGB_ALPHA (in which case need_expand is superfluous anyway), the
803 * background color might actually be gray yet not be flagged as such.
804 * This is not a problem for the current code, which uses
805 * PNG_BACKGROUND_IS_GRAY only to decide when to do the
806 * png_do_gray_to_rgb() transformation.
807 */
808 if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
809 !(color_type & PNG_COLOR_MASK_COLOR))
810 {
811 png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
812 } else if ((png_ptr->transformations & PNG_BACKGROUND) &&
813 !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
814 (png_ptr->transformations & PNG_GRAY_TO_RGB) &&
815 png_ptr->background.red == png_ptr->background.green &&
816 png_ptr->background.red == png_ptr->background.blue)
817 {
818 png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
819 png_ptr->background.gray = png_ptr->background.red;
820 }
821 #endif
822
823 if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
824 (png_ptr->transformations & PNG_EXPAND))
825 {
826 if (!(color_type & PNG_COLOR_MASK_COLOR)) /* i.e., GRAY or GRAY_ALPHA */
827 {
828 /* Expand background and tRNS chunks */
829 switch (png_ptr->bit_depth)
830 {
831 case 1:
832 png_ptr->background.gray *= (png_uint_16)0xff;
833 png_ptr->background.red = png_ptr->background.green
834 = png_ptr->background.blue = png_ptr->background.gray;
835 if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
836 {
837 png_ptr->trans_values.gray *= (png_uint_16)0xff;
838 png_ptr->trans_values.red = png_ptr->trans_values.green
839 = png_ptr->trans_values.blue = png_ptr->trans_values.gray;
840 }
841 break;
842
843 case 2:
844 png_ptr->background.gray *= (png_uint_16)0x55;
845 png_ptr->background.red = png_ptr->background.green
846 = png_ptr->background.blue = png_ptr->background.gray;
847 if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
848 {
849 png_ptr->trans_values.gray *= (png_uint_16)0x55;
850 png_ptr->trans_values.red = png_ptr->trans_values.green
851 = png_ptr->trans_values.blue = png_ptr->trans_values.gray;
852 }
853 break;
854
855 case 4:
856 png_ptr->background.gray *= (png_uint_16)0x11;
857 png_ptr->background.red = png_ptr->background.green
858 = png_ptr->background.blue = png_ptr->background.gray;
859 if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
860 {
861 png_ptr->trans_values.gray *= (png_uint_16)0x11;
862 png_ptr->trans_values.red = png_ptr->trans_values.green
863 = png_ptr->trans_values.blue = png_ptr->trans_values.gray;
864 }
865 break;
866
867 case 8:
868
869 case 16:
870 png_ptr->background.red = png_ptr->background.green
871 = png_ptr->background.blue = png_ptr->background.gray;
872 break;
873 }
874 }
875 else if (color_type == PNG_COLOR_TYPE_PALETTE)
876 {
877 png_ptr->background.red =
878 png_ptr->palette[png_ptr->background.index].red;
879 png_ptr->background.green =
880 png_ptr->palette[png_ptr->background.index].green;
881 png_ptr->background.blue =
882 png_ptr->palette[png_ptr->background.index].blue;
883
884 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
885 if (png_ptr->transformations & PNG_INVERT_ALPHA)
886 {
887 #ifdef PNG_READ_EXPAND_SUPPORTED
888 if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
889 #endif
890 {
891 /* Invert the alpha channel (in tRNS) unless the pixels are
892 * going to be expanded, in which case leave it for later
893 */
894 int i, istop;
895 istop=(int)png_ptr->num_trans;
896 for (i=0; i<istop; i++)
897 png_ptr->trans[i] = (png_byte)(255 - png_ptr->trans[i]);
898 }
899 }
900 #endif
901
902 }
903 }
904 #endif
905
906 #if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
907 png_ptr->background_1 = png_ptr->background;
908 #endif
909 #if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
910
911 if ((color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->num_trans != 0)
912 && (fabs(png_ptr->screen_gamma * png_ptr->gamma - 1.0)
913 < PNG_GAMMA_THRESHOLD))
914 {
915 int i, k;
916 k=0;
917 for (i=0; i<png_ptr->num_trans; i++)
918 {
919 if (png_ptr->trans[i] != 0 && png_ptr->trans[i] != 0xff)
920 k=1; /* Partial transparency is present */
921 }
922 if (k == 0)
923 png_ptr->transformations &= ~PNG_GAMMA;
924 }
925
926 if ((png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) &&
927 png_ptr->gamma != 0.0)
928 {
929 png_build_gamma_table(png_ptr);
930
931 #ifdef PNG_READ_BACKGROUND_SUPPORTED
932 if (png_ptr->transformations & PNG_BACKGROUND)
933 {
934 if (color_type == PNG_COLOR_TYPE_PALETTE)
935 {
936 /* Could skip if no transparency */
937 png_color back, back_1;
938 png_colorp palette = png_ptr->palette;
939 int num_palette = png_ptr->num_palette;
940 int i;
941 if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
942 {
943 back.red = png_ptr->gamma_table[png_ptr->background.red];
944 back.green = png_ptr->gamma_table[png_ptr->background.green];
945 back.blue = png_ptr->gamma_table[png_ptr->background.blue];
946
947 back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
948 back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
949 back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
950 }
951 else
952 {
953 double g, gs;
954
955 switch (png_ptr->background_gamma_type)
956 {
957 case PNG_BACKGROUND_GAMMA_SCREEN:
958 g = (png_ptr->screen_gamma);
959 gs = 1.0;
960 break;
961
962 case PNG_BACKGROUND_GAMMA_FILE:
963 g = 1.0 / (png_ptr->gamma);
964 gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
965 break;
966
967 case PNG_BACKGROUND_GAMMA_UNIQUE:
968 g = 1.0 / (png_ptr->background_gamma);
969 gs = 1.0 / (png_ptr->background_gamma *
970 png_ptr->screen_gamma);
971 break;
972 default:
973 g = 1.0; /* back_1 */
974 gs = 1.0; /* back */
975 }
976
977 if ( fabs(gs - 1.0) < PNG_GAMMA_THRESHOLD)
978 {
979 back.red = (png_byte)png_ptr->background.red;
980 back.green = (png_byte)png_ptr->background.green;
981 back.blue = (png_byte)png_ptr->background.blue;
982 }
983 else
984 {
985 back.red = (png_byte)(pow(
986 (double)png_ptr->background.red/255, gs) * 255.0 + .5);
987 back.green = (png_byte)(pow(
988 (double)png_ptr->background.green/255, gs) * 255.0
989 + .5);
990 back.blue = (png_byte)(pow(
991 (double)png_ptr->background.blue/255, gs) * 255.0 + .5);
992 }
993
994 back_1.red = (png_byte)(pow(
995 (double)png_ptr->background.red/255, g) * 255.0 + .5);
996 back_1.green = (png_byte)(pow(
997 (double)png_ptr->background.green/255, g) * 255.0 + .5);
998 back_1.blue = (png_byte)(pow(
999 (double)png_ptr->background.blue/255, g) * 255.0 + .5);
1000 }
1001 for (i = 0; i < num_palette; i++)
1002 {
1003 if (i < (int)png_ptr->num_trans && png_ptr->trans[i] != 0xff)
1004 {
1005 if (png_ptr->trans[i] == 0)
1006 {
1007 palette[i] = back;
1008 }
1009 else /* if (png_ptr->trans[i] != 0xff) */
1010 {
1011 png_byte v, w;
1012
1013 v = png_ptr->gamma_to_1[palette[i].red];
1014 png_composite(w, v, png_ptr->trans[i], back_1.red);
1015 palette[i].red = png_ptr->gamma_from_1[w];
1016
1017 v = png_ptr->gamma_to_1[palette[i].green];
1018 png_composite(w, v, png_ptr->trans[i], back_1.green);
1019 palette[i].green = png_ptr->gamma_from_1[w];
1020
1021 v = png_ptr->gamma_to_1[palette[i].blue];
1022 png_composite(w, v, png_ptr->trans[i], back_1.blue);
1023 palette[i].blue = png_ptr->gamma_from_1[w];
1024 }
1025 }
1026 else
1027 {
1028 palette[i].red = png_ptr->gamma_table[palette[i].red];
1029 palette[i].green = png_ptr->gamma_table[palette[i].green];
1030 palette[i].blue = png_ptr->gamma_table[palette[i].blue];
1031 }
1032 }
1033 /* Prevent the transformations being done again, and make sure
1034 * that the now spurious alpha channel is stripped - the code
1035 * has just reduced background composition and gamma correction
1036 * to a simple alpha channel strip.
1037 */
1038 png_ptr->transformations &= ~PNG_BACKGROUND;
1039 png_ptr->transformations &= ~PNG_GAMMA;
1040 png_ptr->transformations |= PNG_STRIP_ALPHA;
1041 }
1042 /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
1043 else
1044 /* color_type != PNG_COLOR_TYPE_PALETTE */
1045 {
1046 double m = (double)(((png_uint_32)1 << png_ptr->bit_depth) - 1);
1047 double g = 1.0;
1048 double gs = 1.0;
1049
1050 switch (png_ptr->background_gamma_type)
1051 {
1052 case PNG_BACKGROUND_GAMMA_SCREEN:
1053 g = (png_ptr->screen_gamma);
1054 gs = 1.0;
1055 break;
1056
1057 case PNG_BACKGROUND_GAMMA_FILE:
1058 g = 1.0 / (png_ptr->gamma);
1059 gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
1060 break;
1061
1062 case PNG_BACKGROUND_GAMMA_UNIQUE:
1063 g = 1.0 / (png_ptr->background_gamma);
1064 gs = 1.0 / (png_ptr->background_gamma *
1065 png_ptr->screen_gamma);
1066 break;
1067 }
1068
1069 png_ptr->background_1.gray = (png_uint_16)(pow(
1070 (double)png_ptr->background.gray / m, g) * m + .5);
1071 png_ptr->background.gray = (png_uint_16)(pow(
1072 (double)png_ptr->background.gray / m, gs) * m + .5);
1073
1074 if ((png_ptr->background.red != png_ptr->background.green) ||
1075 (png_ptr->background.red != png_ptr->background.blue) ||
1076 (png_ptr->background.red != png_ptr->background.gray))
1077 {
1078 /* RGB or RGBA with color background */
1079 png_ptr->background_1.red = (png_uint_16)(pow(
1080 (double)png_ptr->background.red / m, g) * m + .5);
1081 png_ptr->background_1.green = (png_uint_16)(pow(
1082 (double)png_ptr->background.green / m, g) * m + .5);
1083 png_ptr->background_1.blue = (png_uint_16)(pow(
1084 (double)png_ptr->background.blue / m, g) * m + .5);
1085 png_ptr->background.red = (png_uint_16)(pow(
1086 (double)png_ptr->background.red / m, gs) * m + .5);
1087 png_ptr->background.green = (png_uint_16)(pow(
1088 (double)png_ptr->background.green / m, gs) * m + .5);
1089 png_ptr->background.blue = (png_uint_16)(pow(
1090 (double)png_ptr->background.blue / m, gs) * m + .5);
1091 }
1092 else
1093 {
1094 /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
1095 png_ptr->background_1.red = png_ptr->background_1.green
1096 = png_ptr->background_1.blue = png_ptr->background_1.gray;
1097 png_ptr->background.red = png_ptr->background.green
1098 = png_ptr->background.blue = png_ptr->background.gray;
1099 }
1100 }
1101 }
1102 else
1103 /* Transformation does not include PNG_BACKGROUND */
1104 #endif /* PNG_READ_BACKGROUND_SUPPORTED */
1105 if (color_type == PNG_COLOR_TYPE_PALETTE)
1106 {
1107 png_colorp palette = png_ptr->palette;
1108 int num_palette = png_ptr->num_palette;
1109 int i;
1110
1111 for (i = 0; i < num_palette; i++)
1112 {
1113 palette[i].red = png_ptr->gamma_table[palette[i].red];
1114 palette[i].green = png_ptr->gamma_table[palette[i].green];
1115 palette[i].blue = png_ptr->gamma_table[palette[i].blue];
1116 }
1117
1118 /* Done the gamma correction. */
1119 png_ptr->transformations &= ~PNG_GAMMA;
1120 }
1121 }
1122 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1123 else
1124 #endif
1125 #endif /* PNG_READ_GAMMA_SUPPORTED && PNG_FLOATING_POINT_SUPPORTED */
1126 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1127 /* No GAMMA transformation */
1128 if ((png_ptr->transformations & PNG_BACKGROUND) &&
1129 (color_type == PNG_COLOR_TYPE_PALETTE))
1130 {
1131 int i;
1132 int istop = (int)png_ptr->num_trans;
1133 png_color back;
1134 png_colorp palette = png_ptr->palette;
1135
1136 back.red = (png_byte)png_ptr->background.red;
1137 back.green = (png_byte)png_ptr->background.green;
1138 back.blue = (png_byte)png_ptr->background.blue;
1139
1140 for (i = 0; i < istop; i++)
1141 {
1142 if (png_ptr->trans[i] == 0)
1143 {
1144 palette[i] = back;
1145 }
1146 else if (png_ptr->trans[i] != 0xff)
1147 {
1148 /* The png_composite() macro is defined in png.h */
1149 png_composite(palette[i].red, palette[i].red,
1150 png_ptr->trans[i], back.red);
1151 png_composite(palette[i].green, palette[i].green,
1152 png_ptr->trans[i], back.green);
1153 png_composite(palette[i].blue, palette[i].blue,
1154 png_ptr->trans[i], back.blue);
1155 }
1156 }
1157
1158 /* Handled alpha, still need to strip the channel. */
1159 png_ptr->transformations &= ~PNG_BACKGROUND;
1160 png_ptr->transformations |= PNG_STRIP_ALPHA;
1161 }
1162 #endif /* PNG_READ_BACKGROUND_SUPPORTED */
1163
1164 #ifdef PNG_READ_SHIFT_SUPPORTED
1165 if ((png_ptr->transformations & PNG_SHIFT) &&
1166 (color_type == PNG_COLOR_TYPE_PALETTE))
1167 {
1168 png_uint_16 i;
1169 png_uint_16 istop = png_ptr->num_palette;
1170 int sr = 8 - png_ptr->sig_bit.red;
1171 int sg = 8 - png_ptr->sig_bit.green;
1172 int sb = 8 - png_ptr->sig_bit.blue;
1173
1174 if (sr < 0 || sr > 8)
1175 sr = 0;
1176 if (sg < 0 || sg > 8)
1177 sg = 0;
1178 if (sb < 0 || sb > 8)
1179 sb = 0;
1180 for (i = 0; i < istop; i++)
1181 {
1182 png_ptr->palette[i].red >>= sr;
1183 png_ptr->palette[i].green >>= sg;
1184 png_ptr->palette[i].blue >>= sb;
1185 }
1186 }
1187 #endif /* PNG_READ_SHIFT_SUPPORTED */
1188 }
1189 #if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \
1190 && !defined(PNG_READ_BACKGROUND_SUPPORTED)
1191 if (png_ptr)
1192 return;
1193 #endif
1194 }
1195
1196 /* Modify the info structure to reflect the transformations. The
1197 * info should be updated so a PNG file could be written with it,
1198 * assuming the transformations result in valid PNG data.
1199 */
1200 void /* PRIVATE */
png_read_transform_info(png_structp png_ptr,png_infop info_ptr)1201 png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
1202 {
1203 png_debug(1, "in png_read_transform_info");
1204
1205 #ifdef PNG_READ_EXPAND_SUPPORTED
1206 if (png_ptr->transformations & PNG_EXPAND)
1207 {
1208 if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1209 {
1210 if (png_ptr->num_trans)
1211 info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
1212 else
1213 info_ptr->color_type = PNG_COLOR_TYPE_RGB;
1214 info_ptr->bit_depth = 8;
1215 info_ptr->num_trans = 0;
1216 }
1217 else
1218 {
1219 if (png_ptr->num_trans)
1220 {
1221 if (png_ptr->transformations & PNG_EXPAND_tRNS)
1222 info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
1223 }
1224 if (info_ptr->bit_depth < 8)
1225 info_ptr->bit_depth = 8;
1226 info_ptr->num_trans = 0;
1227 }
1228 }
1229 #endif
1230
1231 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1232 if (png_ptr->transformations & PNG_BACKGROUND)
1233 {
1234 info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
1235 info_ptr->num_trans = 0;
1236 info_ptr->background = png_ptr->background;
1237 }
1238 #endif
1239
1240 #ifdef PNG_READ_GAMMA_SUPPORTED
1241 if (png_ptr->transformations & PNG_GAMMA)
1242 {
1243 #ifdef PNG_FLOATING_POINT_SUPPORTED
1244 info_ptr->gamma = png_ptr->gamma;
1245 #endif
1246 #ifdef PNG_FIXED_POINT_SUPPORTED
1247 info_ptr->int_gamma = png_ptr->int_gamma;
1248 #endif
1249 }
1250 #endif
1251
1252 #ifdef PNG_READ_16_TO_8_SUPPORTED
1253 if ((png_ptr->transformations & PNG_16_TO_8) && (info_ptr->bit_depth == 16))
1254 info_ptr->bit_depth = 8;
1255 #endif
1256
1257 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1258 if (png_ptr->transformations & PNG_GRAY_TO_RGB)
1259 info_ptr->color_type |= PNG_COLOR_MASK_COLOR;
1260 #endif
1261
1262 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1263 if (png_ptr->transformations & PNG_RGB_TO_GRAY)
1264 info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR;
1265 #endif
1266
1267 #ifdef PNG_READ_DITHER_SUPPORTED
1268 if (png_ptr->transformations & PNG_DITHER)
1269 {
1270 if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
1271 (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
1272 png_ptr->palette_lookup && info_ptr->bit_depth == 8)
1273 {
1274 info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
1275 }
1276 }
1277 #endif
1278
1279 #ifdef PNG_READ_PACK_SUPPORTED
1280 if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
1281 info_ptr->bit_depth = 8;
1282 #endif
1283
1284 if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1285 info_ptr->channels = 1;
1286 else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
1287 info_ptr->channels = 3;
1288 else
1289 info_ptr->channels = 1;
1290
1291 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1292 if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)
1293 info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
1294 #endif
1295
1296 if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
1297 info_ptr->channels++;
1298
1299 #ifdef PNG_READ_FILLER_SUPPORTED
1300 /* STRIP_ALPHA and FILLER allowed: MASK_ALPHA bit stripped above */
1301 if ((png_ptr->transformations & PNG_FILLER) &&
1302 ((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
1303 (info_ptr->color_type == PNG_COLOR_TYPE_GRAY)))
1304 {
1305 info_ptr->channels++;
1306 /* If adding a true alpha channel not just filler */
1307 #ifndef PNG_1_0_X
1308 if (png_ptr->transformations & PNG_ADD_ALPHA)
1309 info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
1310 #endif
1311 }
1312 #endif
1313
1314 #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
1315 defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
1316 if (png_ptr->transformations & PNG_USER_TRANSFORM)
1317 {
1318 if (info_ptr->bit_depth < png_ptr->user_transform_depth)
1319 info_ptr->bit_depth = png_ptr->user_transform_depth;
1320 if (info_ptr->channels < png_ptr->user_transform_channels)
1321 info_ptr->channels = png_ptr->user_transform_channels;
1322 }
1323 #endif
1324
1325 info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
1326 info_ptr->bit_depth);
1327
1328 info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
1329
1330 #ifndef PNG_READ_EXPAND_SUPPORTED
1331 if (png_ptr)
1332 return;
1333 #endif
1334 }
1335
1336 /* Transform the row. The order of transformations is significant,
1337 * and is very touchy. If you add a transformation, take care to
1338 * decide how it fits in with the other transformations here.
1339 */
1340 void /* PRIVATE */
png_do_read_transformations(png_structp png_ptr)1341 png_do_read_transformations(png_structp png_ptr)
1342 {
1343 png_debug(1, "in png_do_read_transformations");
1344
1345 if (png_ptr->row_buf == NULL)
1346 {
1347 #if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE)
1348 char msg[50];
1349
1350 png_snprintf2(msg, 50,
1351 "NULL row buffer for row %ld, pass %d", (long)png_ptr->row_number,
1352 png_ptr->pass);
1353 png_error(png_ptr, msg);
1354 #else
1355 png_error(png_ptr, "NULL row buffer");
1356 #endif
1357 }
1358 #ifdef PNG_WARN_UNINITIALIZED_ROW
1359 if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
1360 /* Application has failed to call either png_read_start_image()
1361 * or png_read_update_info() after setting transforms that expand
1362 * pixels. This check added to libpng-1.2.19
1363 */
1364 #if (PNG_WARN_UNINITIALIZED_ROW==1)
1365 png_error(png_ptr, "Uninitialized row");
1366 #else
1367 png_warning(png_ptr, "Uninitialized row");
1368 #endif
1369 #endif
1370
1371 #ifdef PNG_READ_EXPAND_SUPPORTED
1372 if (png_ptr->transformations & PNG_EXPAND)
1373 {
1374 if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE)
1375 {
1376 png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1,
1377 png_ptr->palette, png_ptr->trans, png_ptr->num_trans);
1378 }
1379 else
1380 {
1381 if (png_ptr->num_trans &&
1382 (png_ptr->transformations & PNG_EXPAND_tRNS))
1383 png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
1384 &(png_ptr->trans_values));
1385 else
1386 png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
1387 NULL);
1388 }
1389 }
1390 #endif
1391
1392 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1393 if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)
1394 png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
1395 PNG_FLAG_FILLER_AFTER | (png_ptr->flags & PNG_FLAG_STRIP_ALPHA));
1396 #endif
1397
1398 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1399 if (png_ptr->transformations & PNG_RGB_TO_GRAY)
1400 {
1401 int rgb_error =
1402 png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info),
1403 png_ptr->row_buf + 1);
1404 if (rgb_error)
1405 {
1406 png_ptr->rgb_to_gray_status=1;
1407 if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
1408 PNG_RGB_TO_GRAY_WARN)
1409 png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
1410 if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
1411 PNG_RGB_TO_GRAY_ERR)
1412 png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
1413 }
1414 }
1415 #endif
1416
1417 /* From Andreas Dilger e-mail to png-implement, 26 March 1998:
1418 *
1419 * In most cases, the "simple transparency" should be done prior to doing
1420 * gray-to-RGB, or you will have to test 3x as many bytes to check if a
1421 * pixel is transparent. You would also need to make sure that the
1422 * transparency information is upgraded to RGB.
1423 *
1424 * To summarize, the current flow is:
1425 * - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
1426 * with background "in place" if transparent,
1427 * convert to RGB if necessary
1428 * - Gray + alpha -> composite with gray background and remove alpha bytes,
1429 * convert to RGB if necessary
1430 *
1431 * To support RGB backgrounds for gray images we need:
1432 * - Gray + simple transparency -> convert to RGB + simple transparency,
1433 * compare 3 or 6 bytes and composite with
1434 * background "in place" if transparent
1435 * (3x compare/pixel compared to doing
1436 * composite with gray bkgrnd)
1437 * - Gray + alpha -> convert to RGB + alpha, composite with background and
1438 * remove alpha bytes (3x float
1439 * operations/pixel compared with composite
1440 * on gray background)
1441 *
1442 * Greg's change will do this. The reason it wasn't done before is for
1443 * performance, as this increases the per-pixel operations. If we would check
1444 * in advance if the background was gray or RGB, and position the gray-to-RGB
1445 * transform appropriately, then it would save a lot of work/time.
1446 */
1447
1448 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1449 /* If gray -> RGB, do so now only if background is non-gray; else do later
1450 * for performance reasons
1451 */
1452 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
1453 !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
1454 png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
1455 #endif
1456
1457 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1458 if ((png_ptr->transformations & PNG_BACKGROUND) &&
1459 ((png_ptr->num_trans != 0 ) ||
1460 (png_ptr->color_type & PNG_COLOR_MASK_ALPHA)))
1461 png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1,
1462 &(png_ptr->trans_values), &(png_ptr->background)
1463 #ifdef PNG_READ_GAMMA_SUPPORTED
1464 , &(png_ptr->background_1),
1465 png_ptr->gamma_table, png_ptr->gamma_from_1,
1466 png_ptr->gamma_to_1, png_ptr->gamma_16_table,
1467 png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1,
1468 png_ptr->gamma_shift
1469 #endif
1470 );
1471 #endif
1472
1473 #ifdef PNG_READ_GAMMA_SUPPORTED
1474 if ((png_ptr->transformations & PNG_GAMMA) &&
1475 #ifdef PNG_READ_BACKGROUND_SUPPORTED
1476 !((png_ptr->transformations & PNG_BACKGROUND) &&
1477 ((png_ptr->num_trans != 0) ||
1478 (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
1479 #endif
1480 (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
1481 png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1,
1482 png_ptr->gamma_table, png_ptr->gamma_16_table,
1483 png_ptr->gamma_shift);
1484 #endif
1485
1486 #ifdef PNG_READ_16_TO_8_SUPPORTED
1487 if (png_ptr->transformations & PNG_16_TO_8)
1488 png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1);
1489 #endif
1490
1491 #ifdef PNG_READ_DITHER_SUPPORTED
1492 if (png_ptr->transformations & PNG_DITHER)
1493 {
1494 png_do_dither((png_row_infop)&(png_ptr->row_info), png_ptr->row_buf + 1,
1495 png_ptr->palette_lookup, png_ptr->dither_index);
1496 if (png_ptr->row_info.rowbytes == (png_uint_32)0)
1497 png_error(png_ptr, "png_do_dither returned rowbytes=0");
1498 }
1499 #endif
1500
1501 #ifdef PNG_READ_INVERT_SUPPORTED
1502 if (png_ptr->transformations & PNG_INVERT_MONO)
1503 png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
1504 #endif
1505
1506 #ifdef PNG_READ_SHIFT_SUPPORTED
1507 if (png_ptr->transformations & PNG_SHIFT)
1508 png_do_unshift(&(png_ptr->row_info), png_ptr->row_buf + 1,
1509 &(png_ptr->shift));
1510 #endif
1511
1512 #ifdef PNG_READ_PACK_SUPPORTED
1513 if (png_ptr->transformations & PNG_PACK)
1514 png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1);
1515 #endif
1516
1517 #ifdef PNG_READ_BGR_SUPPORTED
1518 if (png_ptr->transformations & PNG_BGR)
1519 png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
1520 #endif
1521
1522 #ifdef PNG_READ_PACKSWAP_SUPPORTED
1523 if (png_ptr->transformations & PNG_PACKSWAP)
1524 png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
1525 #endif
1526
1527 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1528 /* If gray -> RGB, do so now only if we did not do so above */
1529 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
1530 (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
1531 png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
1532 #endif
1533
1534 #ifdef PNG_READ_FILLER_SUPPORTED
1535 if (png_ptr->transformations & PNG_FILLER)
1536 png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
1537 (png_uint_32)png_ptr->filler, png_ptr->flags);
1538 #endif
1539
1540 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1541 if (png_ptr->transformations & PNG_INVERT_ALPHA)
1542 png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
1543 #endif
1544
1545 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
1546 if (png_ptr->transformations & PNG_SWAP_ALPHA)
1547 png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
1548 #endif
1549
1550 #ifdef PNG_READ_SWAP_SUPPORTED
1551 if (png_ptr->transformations & PNG_SWAP_BYTES)
1552 png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
1553 #endif
1554
1555 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1556 if (png_ptr->transformations & PNG_USER_TRANSFORM)
1557 {
1558 if (png_ptr->read_user_transform_fn != NULL)
1559 (*(png_ptr->read_user_transform_fn)) /* User read transform function */
1560 (png_ptr, /* png_ptr */
1561 &(png_ptr->row_info), /* row_info: */
1562 /* png_uint_32 width; width of row */
1563 /* png_uint_32 rowbytes; number of bytes in row */
1564 /* png_byte color_type; color type of pixels */
1565 /* png_byte bit_depth; bit depth of samples */
1566 /* png_byte channels; number of channels (1-4) */
1567 /* png_byte pixel_depth; bits per pixel (depth*channels) */
1568 png_ptr->row_buf + 1); /* start of pixel data for row */
1569 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
1570 if (png_ptr->user_transform_depth)
1571 png_ptr->row_info.bit_depth = png_ptr->user_transform_depth;
1572 if (png_ptr->user_transform_channels)
1573 png_ptr->row_info.channels = png_ptr->user_transform_channels;
1574 #endif
1575 png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *
1576 png_ptr->row_info.channels);
1577 png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
1578 png_ptr->row_info.width);
1579 }
1580 #endif
1581
1582 }
1583
1584 #ifdef PNG_READ_PACK_SUPPORTED
1585 /* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
1586 * without changing the actual values. Thus, if you had a row with
1587 * a bit depth of 1, you would end up with bytes that only contained
1588 * the numbers 0 or 1. If you would rather they contain 0 and 255, use
1589 * png_do_shift() after this.
1590 */
1591 void /* PRIVATE */
png_do_unpack(png_row_infop row_info,png_bytep row)1592 png_do_unpack(png_row_infop row_info, png_bytep row)
1593 {
1594 png_debug(1, "in png_do_unpack");
1595
1596 #ifdef PNG_USELESS_TESTS_SUPPORTED
1597 if (row != NULL && row_info != NULL && row_info->bit_depth < 8)
1598 #else
1599 if (row_info->bit_depth < 8)
1600 #endif
1601 {
1602 png_uint_32 i;
1603 png_uint_32 row_width=row_info->width;
1604
1605 switch (row_info->bit_depth)
1606 {
1607 case 1:
1608 {
1609 png_bytep sp = row + (png_size_t)((row_width - 1) >> 3);
1610 png_bytep dp = row + (png_size_t)row_width - 1;
1611 png_uint_32 shift = 7 - (int)((row_width + 7) & 0x07);
1612 for (i = 0; i < row_width; i++)
1613 {
1614 *dp = (png_byte)((*sp >> shift) & 0x01);
1615 if (shift == 7)
1616 {
1617 shift = 0;
1618 sp--;
1619 }
1620 else
1621 shift++;
1622
1623 dp--;
1624 }
1625 break;
1626 }
1627
1628 case 2:
1629 {
1630
1631 png_bytep sp = row + (png_size_t)((row_width - 1) >> 2);
1632 png_bytep dp = row + (png_size_t)row_width - 1;
1633 png_uint_32 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
1634 for (i = 0; i < row_width; i++)
1635 {
1636 *dp = (png_byte)((*sp >> shift) & 0x03);
1637 if (shift == 6)
1638 {
1639 shift = 0;
1640 sp--;
1641 }
1642 else
1643 shift += 2;
1644
1645 dp--;
1646 }
1647 break;
1648 }
1649
1650 case 4:
1651 {
1652 png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
1653 png_bytep dp = row + (png_size_t)row_width - 1;
1654 png_uint_32 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
1655 for (i = 0; i < row_width; i++)
1656 {
1657 *dp = (png_byte)((*sp >> shift) & 0x0f);
1658 if (shift == 4)
1659 {
1660 shift = 0;
1661 sp--;
1662 }
1663 else
1664 shift = 4;
1665
1666 dp--;
1667 }
1668 break;
1669 }
1670 }
1671 row_info->bit_depth = 8;
1672 row_info->pixel_depth = (png_byte)(8 * row_info->channels);
1673 row_info->rowbytes = row_width * row_info->channels;
1674 }
1675 }
1676 #endif
1677
1678 #ifdef PNG_READ_SHIFT_SUPPORTED
1679 /* Reverse the effects of png_do_shift. This routine merely shifts the
1680 * pixels back to their significant bits values. Thus, if you have
1681 * a row of bit depth 8, but only 5 are significant, this will shift
1682 * the values back to 0 through 31.
1683 */
1684 void /* PRIVATE */
png_do_unshift(png_row_infop row_info,png_bytep row,png_color_8p sig_bits)1685 png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
1686 {
1687 png_debug(1, "in png_do_unshift");
1688
1689 if (
1690 #ifdef PNG_USELESS_TESTS_SUPPORTED
1691 row != NULL && row_info != NULL && sig_bits != NULL &&
1692 #endif
1693 row_info->color_type != PNG_COLOR_TYPE_PALETTE)
1694 {
1695 int shift[4];
1696 int channels = 0;
1697 int c;
1698 png_uint_16 value = 0;
1699 png_uint_32 row_width = row_info->width;
1700
1701 if (row_info->color_type & PNG_COLOR_MASK_COLOR)
1702 {
1703 shift[channels++] = row_info->bit_depth - sig_bits->red;
1704 shift[channels++] = row_info->bit_depth - sig_bits->green;
1705 shift[channels++] = row_info->bit_depth - sig_bits->blue;
1706 }
1707 else
1708 {
1709 shift[channels++] = row_info->bit_depth - sig_bits->gray;
1710 }
1711 if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
1712 {
1713 shift[channels++] = row_info->bit_depth - sig_bits->alpha;
1714 }
1715
1716 for (c = 0; c < channels; c++)
1717 {
1718 if (shift[c] <= 0)
1719 shift[c] = 0;
1720 else
1721 value = 1;
1722 }
1723
1724 if (!value)
1725 return;
1726
1727 switch (row_info->bit_depth)
1728 {
1729 case 2:
1730 {
1731 png_bytep bp;
1732 png_uint_32 i;
1733 png_uint_32 istop = row_info->rowbytes;
1734
1735 for (bp = row, i = 0; i < istop; i++)
1736 {
1737 *bp >>= 1;
1738 *bp++ &= 0x55;
1739 }
1740 break;
1741 }
1742
1743 case 4:
1744 {
1745 png_bytep bp = row;
1746 png_uint_32 i;
1747 png_uint_32 istop = row_info->rowbytes;
1748 png_byte mask = (png_byte)((((int)0xf0 >> shift[0]) & (int)0xf0) |
1749 (png_byte)((int)0xf >> shift[0]));
1750
1751 for (i = 0; i < istop; i++)
1752 {
1753 *bp >>= shift[0];
1754 *bp++ &= mask;
1755 }
1756 break;
1757 }
1758
1759 case 8:
1760 {
1761 png_bytep bp = row;
1762 png_uint_32 i;
1763 png_uint_32 istop = row_width * channels;
1764
1765 for (i = 0; i < istop; i++)
1766 {
1767 *bp++ >>= shift[i%channels];
1768 }
1769 break;
1770 }
1771
1772 case 16:
1773 {
1774 png_bytep bp = row;
1775 png_uint_32 i;
1776 png_uint_32 istop = channels * row_width;
1777
1778 for (i = 0; i < istop; i++)
1779 {
1780 value = (png_uint_16)((*bp << 8) + *(bp + 1));
1781 value >>= shift[i%channels];
1782 *bp++ = (png_byte)(value >> 8);
1783 *bp++ = (png_byte)(value & 0xff);
1784 }
1785 break;
1786 }
1787 }
1788 }
1789 }
1790 #endif
1791
1792 #ifdef PNG_READ_16_TO_8_SUPPORTED
1793 /* Chop rows of bit depth 16 down to 8 */
1794 void /* PRIVATE */
png_do_chop(png_row_infop row_info,png_bytep row)1795 png_do_chop(png_row_infop row_info, png_bytep row)
1796 {
1797 png_debug(1, "in png_do_chop");
1798
1799 #ifdef PNG_USELESS_TESTS_SUPPORTED
1800 if (row != NULL && row_info != NULL && row_info->bit_depth == 16)
1801 #else
1802 if (row_info->bit_depth == 16)
1803 #endif
1804 {
1805 png_bytep sp = row;
1806 png_bytep dp = row;
1807 png_uint_32 i;
1808 png_uint_32 istop = row_info->width * row_info->channels;
1809
1810 for (i = 0; i<istop; i++, sp += 2, dp++)
1811 {
1812 #ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
1813 /* This does a more accurate scaling of the 16-bit color
1814 * value, rather than a simple low-byte truncation.
1815 *
1816 * What the ideal calculation should be:
1817 * *dp = (((((png_uint_32)(*sp) << 8) |
1818 * (png_uint_32)(*(sp + 1))) * 255 + 127)
1819 * / (png_uint_32)65535L;
1820 *
1821 * GRR: no, I think this is what it really should be:
1822 * *dp = (((((png_uint_32)(*sp) << 8) |
1823 * (png_uint_32)(*(sp + 1))) + 128L)
1824 * / (png_uint_32)257L;
1825 *
1826 * GRR: here's the exact calculation with shifts:
1827 * temp = (((png_uint_32)(*sp) << 8) |
1828 * (png_uint_32)(*(sp + 1))) + 128L;
1829 * *dp = (temp - (temp >> 8)) >> 8;
1830 *
1831 * Approximate calculation with shift/add instead of multiply/divide:
1832 * *dp = ((((png_uint_32)(*sp) << 8) |
1833 * (png_uint_32)((int)(*(sp + 1)) - *sp)) + 128) >> 8;
1834 *
1835 * What we actually do to avoid extra shifting and conversion:
1836 */
1837
1838 *dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0);
1839 #else
1840 /* Simply discard the low order byte */
1841 *dp = *sp;
1842 #endif
1843 }
1844 row_info->bit_depth = 8;
1845 row_info->pixel_depth = (png_byte)(8 * row_info->channels);
1846 row_info->rowbytes = row_info->width * row_info->channels;
1847 }
1848 }
1849 #endif
1850
1851 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
1852 void /* PRIVATE */
png_do_read_swap_alpha(png_row_infop row_info,png_bytep row)1853 png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
1854 {
1855 png_debug(1, "in png_do_read_swap_alpha");
1856
1857 #ifdef PNG_USELESS_TESTS_SUPPORTED
1858 if (row != NULL && row_info != NULL)
1859 #endif
1860 {
1861 png_uint_32 row_width = row_info->width;
1862 if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
1863 {
1864 /* This converts from RGBA to ARGB */
1865 if (row_info->bit_depth == 8)
1866 {
1867 png_bytep sp = row + row_info->rowbytes;
1868 png_bytep dp = sp;
1869 png_byte save;
1870 png_uint_32 i;
1871
1872 for (i = 0; i < row_width; i++)
1873 {
1874 save = *(--sp);
1875 *(--dp) = *(--sp);
1876 *(--dp) = *(--sp);
1877 *(--dp) = *(--sp);
1878 *(--dp) = save;
1879 }
1880 }
1881 /* This converts from RRGGBBAA to AARRGGBB */
1882 else
1883 {
1884 png_bytep sp = row + row_info->rowbytes;
1885 png_bytep dp = sp;
1886 png_byte save[2];
1887 png_uint_32 i;
1888
1889 for (i = 0; i < row_width; i++)
1890 {
1891 save[0] = *(--sp);
1892 save[1] = *(--sp);
1893 *(--dp) = *(--sp);
1894 *(--dp) = *(--sp);
1895 *(--dp) = *(--sp);
1896 *(--dp) = *(--sp);
1897 *(--dp) = *(--sp);
1898 *(--dp) = *(--sp);
1899 *(--dp) = save[0];
1900 *(--dp) = save[1];
1901 }
1902 }
1903 }
1904 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
1905 {
1906 /* This converts from GA to AG */
1907 if (row_info->bit_depth == 8)
1908 {
1909 png_bytep sp = row + row_info->rowbytes;
1910 png_bytep dp = sp;
1911 png_byte save;
1912 png_uint_32 i;
1913
1914 for (i = 0; i < row_width; i++)
1915 {
1916 save = *(--sp);
1917 *(--dp) = *(--sp);
1918 *(--dp) = save;
1919 }
1920 }
1921 /* This converts from GGAA to AAGG */
1922 else
1923 {
1924 png_bytep sp = row + row_info->rowbytes;
1925 png_bytep dp = sp;
1926 png_byte save[2];
1927 png_uint_32 i;
1928
1929 for (i = 0; i < row_width; i++)
1930 {
1931 save[0] = *(--sp);
1932 save[1] = *(--sp);
1933 *(--dp) = *(--sp);
1934 *(--dp) = *(--sp);
1935 *(--dp) = save[0];
1936 *(--dp) = save[1];
1937 }
1938 }
1939 }
1940 }
1941 }
1942 #endif
1943
1944 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1945 void /* PRIVATE */
png_do_read_invert_alpha(png_row_infop row_info,png_bytep row)1946 png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
1947 {
1948 png_debug(1, "in png_do_read_invert_alpha");
1949
1950 #ifdef PNG_USELESS_TESTS_SUPPORTED
1951 if (row != NULL && row_info != NULL)
1952 #endif
1953 {
1954 png_uint_32 row_width = row_info->width;
1955 if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
1956 {
1957 /* This inverts the alpha channel in RGBA */
1958 if (row_info->bit_depth == 8)
1959 {
1960 png_bytep sp = row + row_info->rowbytes;
1961 png_bytep dp = sp;
1962 png_uint_32 i;
1963
1964 for (i = 0; i < row_width; i++)
1965 {
1966 *(--dp) = (png_byte)(255 - *(--sp));
1967
1968 /* This does nothing:
1969 *(--dp) = *(--sp);
1970 *(--dp) = *(--sp);
1971 *(--dp) = *(--sp);
1972 We can replace it with:
1973 */
1974 sp-=3;
1975 dp=sp;
1976 }
1977 }
1978 /* This inverts the alpha channel in RRGGBBAA */
1979 else
1980 {
1981 png_bytep sp = row + row_info->rowbytes;
1982 png_bytep dp = sp;
1983 png_uint_32 i;
1984
1985 for (i = 0; i < row_width; i++)
1986 {
1987 *(--dp) = (png_byte)(255 - *(--sp));
1988 *(--dp) = (png_byte)(255 - *(--sp));
1989
1990 /* This does nothing:
1991 *(--dp) = *(--sp);
1992 *(--dp) = *(--sp);
1993 *(--dp) = *(--sp);
1994 *(--dp) = *(--sp);
1995 *(--dp) = *(--sp);
1996 *(--dp) = *(--sp);
1997 We can replace it with:
1998 */
1999 sp-=6;
2000 dp=sp;
2001 }
2002 }
2003 }
2004 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
2005 {
2006 /* This inverts the alpha channel in GA */
2007 if (row_info->bit_depth == 8)
2008 {
2009 png_bytep sp = row + row_info->rowbytes;
2010 png_bytep dp = sp;
2011 png_uint_32 i;
2012
2013 for (i = 0; i < row_width; i++)
2014 {
2015 *(--dp) = (png_byte)(255 - *(--sp));
2016 *(--dp) = *(--sp);
2017 }
2018 }
2019 /* This inverts the alpha channel in GGAA */
2020 else
2021 {
2022 png_bytep sp = row + row_info->rowbytes;
2023 png_bytep dp = sp;
2024 png_uint_32 i;
2025
2026 for (i = 0; i < row_width; i++)
2027 {
2028 *(--dp) = (png_byte)(255 - *(--sp));
2029 *(--dp) = (png_byte)(255 - *(--sp));
2030 /*
2031 *(--dp) = *(--sp);
2032 *(--dp) = *(--sp);
2033 */
2034 sp-=2;
2035 dp=sp;
2036 }
2037 }
2038 }
2039 }
2040 }
2041 #endif
2042
2043 #ifdef PNG_READ_FILLER_SUPPORTED
2044 /* Add filler channel if we have RGB color */
2045 void /* PRIVATE */
png_do_read_filler(png_row_infop row_info,png_bytep row,png_uint_32 filler,png_uint_32 flags)2046 png_do_read_filler(png_row_infop row_info, png_bytep row,
2047 png_uint_32 filler, png_uint_32 flags)
2048 {
2049 png_uint_32 i;
2050 png_uint_32 row_width = row_info->width;
2051
2052 png_byte hi_filler = (png_byte)((filler>>8) & 0xff);
2053 png_byte lo_filler = (png_byte)(filler & 0xff);
2054
2055 png_debug(1, "in png_do_read_filler");
2056
2057 if (
2058 #ifdef PNG_USELESS_TESTS_SUPPORTED
2059 row != NULL && row_info != NULL &&
2060 #endif
2061 row_info->color_type == PNG_COLOR_TYPE_GRAY)
2062 {
2063 if (row_info->bit_depth == 8)
2064 {
2065 /* This changes the data from G to GX */
2066 if (flags & PNG_FLAG_FILLER_AFTER)
2067 {
2068 png_bytep sp = row + (png_size_t)row_width;
2069 png_bytep dp = sp + (png_size_t)row_width;
2070 for (i = 1; i < row_width; i++)
2071 {
2072 *(--dp) = lo_filler;
2073 *(--dp) = *(--sp);
2074 }
2075 *(--dp) = lo_filler;
2076 row_info->channels = 2;
2077 row_info->pixel_depth = 16;
2078 row_info->rowbytes = row_width * 2;
2079 }
2080 /* This changes the data from G to XG */
2081 else
2082 {
2083 png_bytep sp = row + (png_size_t)row_width;
2084 png_bytep dp = sp + (png_size_t)row_width;
2085 for (i = 0; i < row_width; i++)
2086 {
2087 *(--dp) = *(--sp);
2088 *(--dp) = lo_filler;
2089 }
2090 row_info->channels = 2;
2091 row_info->pixel_depth = 16;
2092 row_info->rowbytes = row_width * 2;
2093 }
2094 }
2095 else if (row_info->bit_depth == 16)
2096 {
2097 /* This changes the data from GG to GGXX */
2098 if (flags & PNG_FLAG_FILLER_AFTER)
2099 {
2100 png_bytep sp = row + (png_size_t)row_width * 2;
2101 png_bytep dp = sp + (png_size_t)row_width * 2;
2102 for (i = 1; i < row_width; i++)
2103 {
2104 *(--dp) = hi_filler;
2105 *(--dp) = lo_filler;
2106 *(--dp) = *(--sp);
2107 *(--dp) = *(--sp);
2108 }
2109 *(--dp) = hi_filler;
2110 *(--dp) = lo_filler;
2111 row_info->channels = 2;
2112 row_info->pixel_depth = 32;
2113 row_info->rowbytes = row_width * 4;
2114 }
2115 /* This changes the data from GG to XXGG */
2116 else
2117 {
2118 png_bytep sp = row + (png_size_t)row_width * 2;
2119 png_bytep dp = sp + (png_size_t)row_width * 2;
2120 for (i = 0; i < row_width; i++)
2121 {
2122 *(--dp) = *(--sp);
2123 *(--dp) = *(--sp);
2124 *(--dp) = hi_filler;
2125 *(--dp) = lo_filler;
2126 }
2127 row_info->channels = 2;
2128 row_info->pixel_depth = 32;
2129 row_info->rowbytes = row_width * 4;
2130 }
2131 }
2132 } /* COLOR_TYPE == GRAY */
2133 else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
2134 {
2135 if (row_info->bit_depth == 8)
2136 {
2137 /* This changes the data from RGB to RGBX */
2138 if (flags & PNG_FLAG_FILLER_AFTER)
2139 {
2140 png_bytep sp = row + (png_size_t)row_width * 3;
2141 png_bytep dp = sp + (png_size_t)row_width;
2142 for (i = 1; i < row_width; i++)
2143 {
2144 *(--dp) = lo_filler;
2145 *(--dp) = *(--sp);
2146 *(--dp) = *(--sp);
2147 *(--dp) = *(--sp);
2148 }
2149 *(--dp) = lo_filler;
2150 row_info->channels = 4;
2151 row_info->pixel_depth = 32;
2152 row_info->rowbytes = row_width * 4;
2153 }
2154 /* This changes the data from RGB to XRGB */
2155 else
2156 {
2157 png_bytep sp = row + (png_size_t)row_width * 3;
2158 png_bytep dp = sp + (png_size_t)row_width;
2159 for (i = 0; i < row_width; i++)
2160 {
2161 *(--dp) = *(--sp);
2162 *(--dp) = *(--sp);
2163 *(--dp) = *(--sp);
2164 *(--dp) = lo_filler;
2165 }
2166 row_info->channels = 4;
2167 row_info->pixel_depth = 32;
2168 row_info->rowbytes = row_width * 4;
2169 }
2170 }
2171 else if (row_info->bit_depth == 16)
2172 {
2173 /* This changes the data from RRGGBB to RRGGBBXX */
2174 if (flags & PNG_FLAG_FILLER_AFTER)
2175 {
2176 png_bytep sp = row + (png_size_t)row_width * 6;
2177 png_bytep dp = sp + (png_size_t)row_width * 2;
2178 for (i = 1; i < row_width; i++)
2179 {
2180 *(--dp) = hi_filler;
2181 *(--dp) = lo_filler;
2182 *(--dp) = *(--sp);
2183 *(--dp) = *(--sp);
2184 *(--dp) = *(--sp);
2185 *(--dp) = *(--sp);
2186 *(--dp) = *(--sp);
2187 *(--dp) = *(--sp);
2188 }
2189 *(--dp) = hi_filler;
2190 *(--dp) = lo_filler;
2191 row_info->channels = 4;
2192 row_info->pixel_depth = 64;
2193 row_info->rowbytes = row_width * 8;
2194 }
2195 /* This changes the data from RRGGBB to XXRRGGBB */
2196 else
2197 {
2198 png_bytep sp = row + (png_size_t)row_width * 6;
2199 png_bytep dp = sp + (png_size_t)row_width * 2;
2200 for (i = 0; i < row_width; i++)
2201 {
2202 *(--dp) = *(--sp);
2203 *(--dp) = *(--sp);
2204 *(--dp) = *(--sp);
2205 *(--dp) = *(--sp);
2206 *(--dp) = *(--sp);
2207 *(--dp) = *(--sp);
2208 *(--dp) = hi_filler;
2209 *(--dp) = lo_filler;
2210 }
2211 row_info->channels = 4;
2212 row_info->pixel_depth = 64;
2213 row_info->rowbytes = row_width * 8;
2214 }
2215 }
2216 } /* COLOR_TYPE == RGB */
2217 }
2218 #endif
2219
2220 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
2221 /* Expand grayscale files to RGB, with or without alpha */
2222 void /* PRIVATE */
png_do_gray_to_rgb(png_row_infop row_info,png_bytep row)2223 png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
2224 {
2225 png_uint_32 i;
2226 png_uint_32 row_width = row_info->width;
2227
2228 png_debug(1, "in png_do_gray_to_rgb");
2229
2230 if (row_info->bit_depth >= 8 &&
2231 #ifdef PNG_USELESS_TESTS_SUPPORTED
2232 row != NULL && row_info != NULL &&
2233 #endif
2234 !(row_info->color_type & PNG_COLOR_MASK_COLOR))
2235 {
2236 if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
2237 {
2238 if (row_info->bit_depth == 8)
2239 {
2240 png_bytep sp = row + (png_size_t)row_width - 1;
2241 png_bytep dp = sp + (png_size_t)row_width * 2;
2242 for (i = 0; i < row_width; i++)
2243 {
2244 *(dp--) = *sp;
2245 *(dp--) = *sp;
2246 *(dp--) = *(sp--);
2247 }
2248 }
2249 else
2250 {
2251 png_bytep sp = row + (png_size_t)row_width * 2 - 1;
2252 png_bytep dp = sp + (png_size_t)row_width * 4;
2253 for (i = 0; i < row_width; i++)
2254 {
2255 *(dp--) = *sp;
2256 *(dp--) = *(sp - 1);
2257 *(dp--) = *sp;
2258 *(dp--) = *(sp - 1);
2259 *(dp--) = *(sp--);
2260 *(dp--) = *(sp--);
2261 }
2262 }
2263 }
2264 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
2265 {
2266 if (row_info->bit_depth == 8)
2267 {
2268 png_bytep sp = row + (png_size_t)row_width * 2 - 1;
2269 png_bytep dp = sp + (png_size_t)row_width * 2;
2270 for (i = 0; i < row_width; i++)
2271 {
2272 *(dp--) = *(sp--);
2273 *(dp--) = *sp;
2274 *(dp--) = *sp;
2275 *(dp--) = *(sp--);
2276 }
2277 }
2278 else
2279 {
2280 png_bytep sp = row + (png_size_t)row_width * 4 - 1;
2281 png_bytep dp = sp + (png_size_t)row_width * 4;
2282 for (i = 0; i < row_width; i++)
2283 {
2284 *(dp--) = *(sp--);
2285 *(dp--) = *(sp--);
2286 *(dp--) = *sp;
2287 *(dp--) = *(sp - 1);
2288 *(dp--) = *sp;
2289 *(dp--) = *(sp - 1);
2290 *(dp--) = *(sp--);
2291 *(dp--) = *(sp--);
2292 }
2293 }
2294 }
2295 row_info->channels += (png_byte)2;
2296 row_info->color_type |= PNG_COLOR_MASK_COLOR;
2297 row_info->pixel_depth = (png_byte)(row_info->channels *
2298 row_info->bit_depth);
2299 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
2300 }
2301 }
2302 #endif
2303
2304 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2305 /* Reduce RGB files to grayscale, with or without alpha
2306 * using the equation given in Poynton's ColorFAQ at
2307 * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008)
2308 * New link:
2309 * <http://www.poynton.com/notes/colour_and_gamma/>
2310 * Charles Poynton poynton at poynton.com
2311 *
2312 * Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
2313 *
2314 * We approximate this with
2315 *
2316 * Y = 0.21268 * R + 0.7151 * G + 0.07217 * B
2317 *
2318 * which can be expressed with integers as
2319 *
2320 * Y = (6969 * R + 23434 * G + 2365 * B)/32768
2321 *
2322 * The calculation is to be done in a linear colorspace.
2323 *
2324 * Other integer coefficents can be used via png_set_rgb_to_gray().
2325 */
2326 int /* PRIVATE */
png_do_rgb_to_gray(png_structp png_ptr,png_row_infop row_info,png_bytep row)2327 png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
2328
2329 {
2330 png_uint_32 i;
2331
2332 png_uint_32 row_width = row_info->width;
2333 int rgb_error = 0;
2334
2335 png_debug(1, "in png_do_rgb_to_gray");
2336
2337 if (
2338 #ifdef PNG_USELESS_TESTS_SUPPORTED
2339 row != NULL && row_info != NULL &&
2340 #endif
2341 (row_info->color_type & PNG_COLOR_MASK_COLOR))
2342 {
2343 png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
2344 png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
2345 png_uint_32 bc = png_ptr->rgb_to_gray_blue_coeff;
2346
2347 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
2348 {
2349 if (row_info->bit_depth == 8)
2350 {
2351 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
2352 if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
2353 {
2354 png_bytep sp = row;
2355 png_bytep dp = row;
2356
2357 for (i = 0; i < row_width; i++)
2358 {
2359 png_byte red = png_ptr->gamma_to_1[*(sp++)];
2360 png_byte green = png_ptr->gamma_to_1[*(sp++)];
2361 png_byte blue = png_ptr->gamma_to_1[*(sp++)];
2362 if (red != green || red != blue)
2363 {
2364 rgb_error |= 1;
2365 *(dp++) = png_ptr->gamma_from_1[
2366 (rc*red + gc*green + bc*blue)>>15];
2367 }
2368 else
2369 *(dp++) = *(sp - 1);
2370 }
2371 }
2372 else
2373 #endif
2374 {
2375 png_bytep sp = row;
2376 png_bytep dp = row;
2377 for (i = 0; i < row_width; i++)
2378 {
2379 png_byte red = *(sp++);
2380 png_byte green = *(sp++);
2381 png_byte blue = *(sp++);
2382 if (red != green || red != blue)
2383 {
2384 rgb_error |= 1;
2385 *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
2386 }
2387 else
2388 *(dp++) = *(sp - 1);
2389 }
2390 }
2391 }
2392
2393 else /* RGB bit_depth == 16 */
2394 {
2395 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
2396 if (png_ptr->gamma_16_to_1 != NULL &&
2397 png_ptr->gamma_16_from_1 != NULL)
2398 {
2399 png_bytep sp = row;
2400 png_bytep dp = row;
2401 for (i = 0; i < row_width; i++)
2402 {
2403 png_uint_16 red, green, blue, w;
2404
2405 red = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
2406 green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
2407 blue = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
2408
2409 if (red == green && red == blue)
2410 w = red;
2411 else
2412 {
2413 png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) >>
2414 png_ptr->gamma_shift][red>>8];
2415 png_uint_16 green_1 =
2416 png_ptr->gamma_16_to_1[(green&0xff) >>
2417 png_ptr->gamma_shift][green>>8];
2418 png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) >>
2419 png_ptr->gamma_shift][blue>>8];
2420 png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1
2421 + bc*blue_1)>>15);
2422 w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
2423 png_ptr->gamma_shift][gray16 >> 8];
2424 rgb_error |= 1;
2425 }
2426
2427 *(dp++) = (png_byte)((w>>8) & 0xff);
2428 *(dp++) = (png_byte)(w & 0xff);
2429 }
2430 }
2431 else
2432 #endif
2433 {
2434 png_bytep sp = row;
2435 png_bytep dp = row;
2436 for (i = 0; i < row_width; i++)
2437 {
2438 png_uint_16 red, green, blue, gray16;
2439
2440 red = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
2441 green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
2442 blue = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
2443
2444 if (red != green || red != blue)
2445 rgb_error |= 1;
2446 gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
2447 *(dp++) = (png_byte)((gray16>>8) & 0xff);
2448 *(dp++) = (png_byte)(gray16 & 0xff);
2449 }
2450 }
2451 }
2452 }
2453 if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
2454 {
2455 if (row_info->bit_depth == 8)
2456 {
2457 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
2458 if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
2459 {
2460 png_bytep sp = row;
2461 png_bytep dp = row;
2462 for (i = 0; i < row_width; i++)
2463 {
2464 png_byte red = png_ptr->gamma_to_1[*(sp++)];
2465 png_byte green = png_ptr->gamma_to_1[*(sp++)];
2466 png_byte blue = png_ptr->gamma_to_1[*(sp++)];
2467 if (red != green || red != blue)
2468 rgb_error |= 1;
2469 *(dp++) = png_ptr->gamma_from_1
2470 [(rc*red + gc*green + bc*blue)>>15];
2471 *(dp++) = *(sp++); /* alpha */
2472 }
2473 }
2474 else
2475 #endif
2476 {
2477 png_bytep sp = row;
2478 png_bytep dp = row;
2479 for (i = 0; i < row_width; i++)
2480 {
2481 png_byte red = *(sp++);
2482 png_byte green = *(sp++);
2483 png_byte blue = *(sp++);
2484 if (red != green || red != blue)
2485 rgb_error |= 1;
2486 *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
2487 *(dp++) = *(sp++); /* alpha */
2488 }
2489 }
2490 }
2491 else /* RGBA bit_depth == 16 */
2492 {
2493 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
2494 if (png_ptr->gamma_16_to_1 != NULL &&
2495 png_ptr->gamma_16_from_1 != NULL)
2496 {
2497 png_bytep sp = row;
2498 png_bytep dp = row;
2499 for (i = 0; i < row_width; i++)
2500 {
2501 png_uint_16 red, green, blue, w;
2502
2503 red = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
2504 green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
2505 blue = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
2506
2507 if (red == green && red == blue)
2508 w = red;
2509 else
2510 {
2511 png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) >>
2512 png_ptr->gamma_shift][red>>8];
2513 png_uint_16 green_1 =
2514 png_ptr->gamma_16_to_1[(green&0xff) >>
2515 png_ptr->gamma_shift][green>>8];
2516 png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) >>
2517 png_ptr->gamma_shift][blue>>8];
2518 png_uint_16 gray16 = (png_uint_16)((rc * red_1
2519 + gc * green_1 + bc * blue_1)>>15);
2520 w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
2521 png_ptr->gamma_shift][gray16 >> 8];
2522 rgb_error |= 1;
2523 }
2524
2525 *(dp++) = (png_byte)((w>>8) & 0xff);
2526 *(dp++) = (png_byte)(w & 0xff);
2527 *(dp++) = *(sp++); /* alpha */
2528 *(dp++) = *(sp++);
2529 }
2530 }
2531 else
2532 #endif
2533 {
2534 png_bytep sp = row;
2535 png_bytep dp = row;
2536 for (i = 0; i < row_width; i++)
2537 {
2538 png_uint_16 red, green, blue, gray16;
2539 red = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
2540 green = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
2541 blue = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
2542 if (red != green || red != blue)
2543 rgb_error |= 1;
2544 gray16 = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
2545 *(dp++) = (png_byte)((gray16>>8) & 0xff);
2546 *(dp++) = (png_byte)(gray16 & 0xff);
2547 *(dp++) = *(sp++); /* alpha */
2548 *(dp++) = *(sp++);
2549 }
2550 }
2551 }
2552 }
2553 row_info->channels -= (png_byte)2;
2554 row_info->color_type &= ~PNG_COLOR_MASK_COLOR;
2555 row_info->pixel_depth = (png_byte)(row_info->channels *
2556 row_info->bit_depth);
2557 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
2558 }
2559 return rgb_error;
2560 }
2561 #endif
2562
2563 /* Build a grayscale palette. Palette is assumed to be 1 << bit_depth
2564 * large of png_color. This lets grayscale images be treated as
2565 * paletted. Most useful for gamma correction and simplification
2566 * of code.
2567 */
2568 void PNGAPI
png_build_grayscale_palette(int bit_depth,png_colorp palette)2569 png_build_grayscale_palette(int bit_depth, png_colorp palette)
2570 {
2571 int num_palette;
2572 int color_inc;
2573 int i;
2574 int v;
2575
2576 png_debug(1, "in png_do_build_grayscale_palette");
2577
2578 if (palette == NULL)
2579 return;
2580
2581 switch (bit_depth)
2582 {
2583 case 1:
2584 num_palette = 2;
2585 color_inc = 0xff;
2586 break;
2587
2588 case 2:
2589 num_palette = 4;
2590 color_inc = 0x55;
2591 break;
2592
2593 case 4:
2594 num_palette = 16;
2595 color_inc = 0x11;
2596 break;
2597
2598 case 8:
2599 num_palette = 256;
2600 color_inc = 1;
2601 break;
2602
2603 default:
2604 num_palette = 0;
2605 color_inc = 0;
2606 break;
2607 }
2608
2609 for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
2610 {
2611 palette[i].red = (png_byte)v;
2612 palette[i].green = (png_byte)v;
2613 palette[i].blue = (png_byte)v;
2614 }
2615 }
2616
2617 /* This function is currently unused. Do we really need it? */
2618 #if defined(PNG_READ_DITHER_SUPPORTED) && \
2619 defined(PNG_CORRECT_PALETTE_SUPPORTED)
2620 void /* PRIVATE */
png_correct_palette(png_structp png_ptr,png_colorp palette,int num_palette)2621 png_correct_palette(png_structp png_ptr, png_colorp palette,
2622 int num_palette)
2623 {
2624 png_debug(1, "in png_correct_palette");
2625
2626 #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
2627 defined(PNG_READ_GAMMA_SUPPORTED) && \
2628 defined(PNG_FLOATING_POINT_SUPPORTED)
2629 if (png_ptr->transformations & (PNG_GAMMA | PNG_BACKGROUND))
2630 {
2631 png_color back, back_1;
2632
2633 if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
2634 {
2635 back.red = png_ptr->gamma_table[png_ptr->background.red];
2636 back.green = png_ptr->gamma_table[png_ptr->background.green];
2637 back.blue = png_ptr->gamma_table[png_ptr->background.blue];
2638
2639 back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
2640 back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
2641 back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
2642 }
2643 else
2644 {
2645 double g;
2646
2647 g = 1.0 / (png_ptr->background_gamma * png_ptr->screen_gamma);
2648
2649 if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_SCREEN
2650 || fabs(g - 1.0) < PNG_GAMMA_THRESHOLD)
2651 {
2652 back.red = png_ptr->background.red;
2653 back.green = png_ptr->background.green;
2654 back.blue = png_ptr->background.blue;
2655 }
2656 else
2657 {
2658 back.red =
2659 (png_byte)(pow((double)png_ptr->background.red/255, g) *
2660 255.0 + 0.5);
2661 back.green =
2662 (png_byte)(pow((double)png_ptr->background.green/255, g) *
2663 255.0 + 0.5);
2664 back.blue =
2665 (png_byte)(pow((double)png_ptr->background.blue/255, g) *
2666 255.0 + 0.5);
2667 }
2668
2669 g = 1.0 / png_ptr->background_gamma;
2670
2671 back_1.red =
2672 (png_byte)(pow((double)png_ptr->background.red/255, g) *
2673 255.0 + 0.5);
2674 back_1.green =
2675 (png_byte)(pow((double)png_ptr->background.green/255, g) *
2676 255.0 + 0.5);
2677 back_1.blue =
2678 (png_byte)(pow((double)png_ptr->background.blue/255, g) *
2679 255.0 + 0.5);
2680 }
2681
2682 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
2683 {
2684 png_uint_32 i;
2685
2686 for (i = 0; i < (png_uint_32)num_palette; i++)
2687 {
2688 if (i < png_ptr->num_trans && png_ptr->trans[i] == 0)
2689 {
2690 palette[i] = back;
2691 }
2692 else if (i < png_ptr->num_trans && png_ptr->trans[i] != 0xff)
2693 {
2694 png_byte v, w;
2695
2696 v = png_ptr->gamma_to_1[png_ptr->palette[i].red];
2697 png_composite(w, v, png_ptr->trans[i], back_1.red);
2698 palette[i].red = png_ptr->gamma_from_1[w];
2699
2700 v = png_ptr->gamma_to_1[png_ptr->palette[i].green];
2701 png_composite(w, v, png_ptr->trans[i], back_1.green);
2702 palette[i].green = png_ptr->gamma_from_1[w];
2703
2704 v = png_ptr->gamma_to_1[png_ptr->palette[i].blue];
2705 png_composite(w, v, png_ptr->trans[i], back_1.blue);
2706 palette[i].blue = png_ptr->gamma_from_1[w];
2707 }
2708 else
2709 {
2710 palette[i].red = png_ptr->gamma_table[palette[i].red];
2711 palette[i].green = png_ptr->gamma_table[palette[i].green];
2712 palette[i].blue = png_ptr->gamma_table[palette[i].blue];
2713 }
2714 }
2715 }
2716 else
2717 {
2718 int i;
2719
2720 for (i = 0; i < num_palette; i++)
2721 {
2722 if (palette[i].red == (png_byte)png_ptr->trans_values.gray)
2723 {
2724 palette[i] = back;
2725 }
2726 else
2727 {
2728 palette[i].red = png_ptr->gamma_table[palette[i].red];
2729 palette[i].green = png_ptr->gamma_table[palette[i].green];
2730 palette[i].blue = png_ptr->gamma_table[palette[i].blue];
2731 }
2732 }
2733 }
2734 }
2735 else
2736 #endif
2737 #ifdef PNG_READ_GAMMA_SUPPORTED
2738 if (png_ptr->transformations & PNG_GAMMA)
2739 {
2740 int i;
2741
2742 for (i = 0; i < num_palette; i++)
2743 {
2744 palette[i].red = png_ptr->gamma_table[palette[i].red];
2745 palette[i].green = png_ptr->gamma_table[palette[i].green];
2746 palette[i].blue = png_ptr->gamma_table[palette[i].blue];
2747 }
2748 }
2749 #ifdef PNG_READ_BACKGROUND_SUPPORTED
2750 else
2751 #endif
2752 #endif
2753 #ifdef PNG_READ_BACKGROUND_SUPPORTED
2754 if (png_ptr->transformations & PNG_BACKGROUND)
2755 {
2756 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
2757 {
2758 png_color back;
2759
2760 back.red = (png_byte)png_ptr->background.red;
2761 back.green = (png_byte)png_ptr->background.green;
2762 back.blue = (png_byte)png_ptr->background.blue;
2763
2764 for (i = 0; i < (int)png_ptr->num_trans; i++)
2765 {
2766 if (png_ptr->trans[i] == 0)
2767 {
2768 palette[i].red = back.red;
2769 palette[i].green = back.green;
2770 palette[i].blue = back.blue;
2771 }
2772 else if (png_ptr->trans[i] != 0xff)
2773 {
2774 png_composite(palette[i].red, png_ptr->palette[i].red,
2775 png_ptr->trans[i], back.red);
2776 png_composite(palette[i].green, png_ptr->palette[i].green,
2777 png_ptr->trans[i], back.green);
2778 png_composite(palette[i].blue, png_ptr->palette[i].blue,
2779 png_ptr->trans[i], back.blue);
2780 }
2781 }
2782 }
2783 else /* Assume grayscale palette (what else could it be?) */
2784 {
2785 int i;
2786
2787 for (i = 0; i < num_palette; i++)
2788 {
2789 if (i == (png_byte)png_ptr->trans_values.gray)
2790 {
2791 palette[i].red = (png_byte)png_ptr->background.red;
2792 palette[i].green = (png_byte)png_ptr->background.green;
2793 palette[i].blue = (png_byte)png_ptr->background.blue;
2794 }
2795 }
2796 }
2797 }
2798 #endif
2799 }
2800 #endif
2801
2802 #ifdef PNG_READ_BACKGROUND_SUPPORTED
2803 /* Replace any alpha or transparency with the supplied background color.
2804 * "background" is already in the screen gamma, while "background_1" is
2805 * at a gamma of 1.0. Paletted files have already been taken care of.
2806 */
2807 void /* PRIVATE */
png_do_background(png_row_infop row_info,png_bytep row,png_color_16p trans_values,png_color_16p background,png_color_16p background_1,png_bytep gamma_table,png_bytep gamma_from_1,png_bytep gamma_to_1,png_uint_16pp gamma_16,png_uint_16pp gamma_16_from_1,png_uint_16pp gamma_16_to_1,int gamma_shift)2808 png_do_background(png_row_infop row_info, png_bytep row,
2809 png_color_16p trans_values, png_color_16p background
2810 #ifdef PNG_READ_GAMMA_SUPPORTED
2811 , png_color_16p background_1,
2812 png_bytep gamma_table, png_bytep gamma_from_1, png_bytep gamma_to_1,
2813 png_uint_16pp gamma_16, png_uint_16pp gamma_16_from_1,
2814 png_uint_16pp gamma_16_to_1, int gamma_shift
2815 #endif
2816 )
2817 {
2818 png_bytep sp, dp;
2819 png_uint_32 i;
2820 png_uint_32 row_width=row_info->width;
2821 int shift;
2822
2823 png_debug(1, "in png_do_background");
2824
2825 if (background != NULL &&
2826 #ifdef PNG_USELESS_TESTS_SUPPORTED
2827 row != NULL && row_info != NULL &&
2828 #endif
2829 (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) ||
2830 (row_info->color_type != PNG_COLOR_TYPE_PALETTE && trans_values)))
2831 {
2832 switch (row_info->color_type)
2833 {
2834 case PNG_COLOR_TYPE_GRAY:
2835 {
2836 switch (row_info->bit_depth)
2837 {
2838 case 1:
2839 {
2840 sp = row;
2841 shift = 7;
2842 for (i = 0; i < row_width; i++)
2843 {
2844 if ((png_uint_16)((*sp >> shift) & 0x01)
2845 == trans_values->gray)
2846 {
2847 *sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
2848 *sp |= (png_byte)(background->gray << shift);
2849 }
2850 if (!shift)
2851 {
2852 shift = 7;
2853 sp++;
2854 }
2855 else
2856 shift--;
2857 }
2858 break;
2859 }
2860
2861 case 2:
2862 {
2863 #ifdef PNG_READ_GAMMA_SUPPORTED
2864 if (gamma_table != NULL)
2865 {
2866 sp = row;
2867 shift = 6;
2868 for (i = 0; i < row_width; i++)
2869 {
2870 if ((png_uint_16)((*sp >> shift) & 0x03)
2871 == trans_values->gray)
2872 {
2873 *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
2874 *sp |= (png_byte)(background->gray << shift);
2875 }
2876 else
2877 {
2878 png_byte p = (png_byte)((*sp >> shift) & 0x03);
2879 png_byte g = (png_byte)((gamma_table [p | (p << 2) |
2880 (p << 4) | (p << 6)] >> 6) & 0x03);
2881 *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
2882 *sp |= (png_byte)(g << shift);
2883 }
2884 if (!shift)
2885 {
2886 shift = 6;
2887 sp++;
2888 }
2889 else
2890 shift -= 2;
2891 }
2892 }
2893 else
2894 #endif
2895 {
2896 sp = row;
2897 shift = 6;
2898 for (i = 0; i < row_width; i++)
2899 {
2900 if ((png_uint_16)((*sp >> shift) & 0x03)
2901 == trans_values->gray)
2902 {
2903 *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
2904 *sp |= (png_byte)(background->gray << shift);
2905 }
2906 if (!shift)
2907 {
2908 shift = 6;
2909 sp++;
2910 }
2911 else
2912 shift -= 2;
2913 }
2914 }
2915 break;
2916 }
2917
2918 case 4:
2919 {
2920 #ifdef PNG_READ_GAMMA_SUPPORTED
2921 if (gamma_table != NULL)
2922 {
2923 sp = row;
2924 shift = 4;
2925 for (i = 0; i < row_width; i++)
2926 {
2927 if ((png_uint_16)((*sp >> shift) & 0x0f)
2928 == trans_values->gray)
2929 {
2930 *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
2931 *sp |= (png_byte)(background->gray << shift);
2932 }
2933 else
2934 {
2935 png_byte p = (png_byte)((*sp >> shift) & 0x0f);
2936 png_byte g = (png_byte)((gamma_table[p |
2937 (p << 4)] >> 4) & 0x0f);
2938 *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
2939 *sp |= (png_byte)(g << shift);
2940 }
2941 if (!shift)
2942 {
2943 shift = 4;
2944 sp++;
2945 }
2946 else
2947 shift -= 4;
2948 }
2949 }
2950 else
2951 #endif
2952 {
2953 sp = row;
2954 shift = 4;
2955 for (i = 0; i < row_width; i++)
2956 {
2957 if ((png_uint_16)((*sp >> shift) & 0x0f)
2958 == trans_values->gray)
2959 {
2960 *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
2961 *sp |= (png_byte)(background->gray << shift);
2962 }
2963 if (!shift)
2964 {
2965 shift = 4;
2966 sp++;
2967 }
2968 else
2969 shift -= 4;
2970 }
2971 }
2972 break;
2973 }
2974
2975 case 8:
2976 {
2977 #ifdef PNG_READ_GAMMA_SUPPORTED
2978 if (gamma_table != NULL)
2979 {
2980 sp = row;
2981 for (i = 0; i < row_width; i++, sp++)
2982 {
2983 if (*sp == trans_values->gray)
2984 {
2985 *sp = (png_byte)background->gray;
2986 }
2987 else
2988 {
2989 *sp = gamma_table[*sp];
2990 }
2991 }
2992 }
2993 else
2994 #endif
2995 {
2996 sp = row;
2997 for (i = 0; i < row_width; i++, sp++)
2998 {
2999 if (*sp == trans_values->gray)
3000 {
3001 *sp = (png_byte)background->gray;
3002 }
3003 }
3004 }
3005 break;
3006 }
3007
3008 case 16:
3009 {
3010 #ifdef PNG_READ_GAMMA_SUPPORTED
3011 if (gamma_16 != NULL)
3012 {
3013 sp = row;
3014 for (i = 0; i < row_width; i++, sp += 2)
3015 {
3016 png_uint_16 v;
3017
3018 v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3019 if (v == trans_values->gray)
3020 {
3021 /* Background is already in screen gamma */
3022 *sp = (png_byte)((background->gray >> 8) & 0xff);
3023 *(sp + 1) = (png_byte)(background->gray & 0xff);
3024 }
3025 else
3026 {
3027 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
3028 *sp = (png_byte)((v >> 8) & 0xff);
3029 *(sp + 1) = (png_byte)(v & 0xff);
3030 }
3031 }
3032 }
3033 else
3034 #endif
3035 {
3036 sp = row;
3037 for (i = 0; i < row_width; i++, sp += 2)
3038 {
3039 png_uint_16 v;
3040
3041 v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3042 if (v == trans_values->gray)
3043 {
3044 *sp = (png_byte)((background->gray >> 8) & 0xff);
3045 *(sp + 1) = (png_byte)(background->gray & 0xff);
3046 }
3047 }
3048 }
3049 break;
3050 }
3051 }
3052 break;
3053 }
3054
3055 case PNG_COLOR_TYPE_RGB:
3056 {
3057 if (row_info->bit_depth == 8)
3058 {
3059 #ifdef PNG_READ_GAMMA_SUPPORTED
3060 if (gamma_table != NULL)
3061 {
3062 sp = row;
3063 for (i = 0; i < row_width; i++, sp += 3)
3064 {
3065 if (*sp == trans_values->red &&
3066 *(sp + 1) == trans_values->green &&
3067 *(sp + 2) == trans_values->blue)
3068 {
3069 *sp = (png_byte)background->red;
3070 *(sp + 1) = (png_byte)background->green;
3071 *(sp + 2) = (png_byte)background->blue;
3072 }
3073 else
3074 {
3075 *sp = gamma_table[*sp];
3076 *(sp + 1) = gamma_table[*(sp + 1)];
3077 *(sp + 2) = gamma_table[*(sp + 2)];
3078 }
3079 }
3080 }
3081 else
3082 #endif
3083 {
3084 sp = row;
3085 for (i = 0; i < row_width; i++, sp += 3)
3086 {
3087 if (*sp == trans_values->red &&
3088 *(sp + 1) == trans_values->green &&
3089 *(sp + 2) == trans_values->blue)
3090 {
3091 *sp = (png_byte)background->red;
3092 *(sp + 1) = (png_byte)background->green;
3093 *(sp + 2) = (png_byte)background->blue;
3094 }
3095 }
3096 }
3097 }
3098 else /* if (row_info->bit_depth == 16) */
3099 {
3100 #ifdef PNG_READ_GAMMA_SUPPORTED
3101 if (gamma_16 != NULL)
3102 {
3103 sp = row;
3104 for (i = 0; i < row_width; i++, sp += 6)
3105 {
3106 png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3107 png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
3108 png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5));
3109 if (r == trans_values->red && g == trans_values->green &&
3110 b == trans_values->blue)
3111 {
3112 /* Background is already in screen gamma */
3113 *sp = (png_byte)((background->red >> 8) & 0xff);
3114 *(sp + 1) = (png_byte)(background->red & 0xff);
3115 *(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
3116 *(sp + 3) = (png_byte)(background->green & 0xff);
3117 *(sp + 4) = (png_byte)((background->blue >> 8) & 0xff);
3118 *(sp + 5) = (png_byte)(background->blue & 0xff);
3119 }
3120 else
3121 {
3122 png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
3123 *sp = (png_byte)((v >> 8) & 0xff);
3124 *(sp + 1) = (png_byte)(v & 0xff);
3125 v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
3126 *(sp + 2) = (png_byte)((v >> 8) & 0xff);
3127 *(sp + 3) = (png_byte)(v & 0xff);
3128 v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
3129 *(sp + 4) = (png_byte)((v >> 8) & 0xff);
3130 *(sp + 5) = (png_byte)(v & 0xff);
3131 }
3132 }
3133 }
3134 else
3135 #endif
3136 {
3137 sp = row;
3138 for (i = 0; i < row_width; i++, sp += 6)
3139 {
3140 png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp+1));
3141 png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
3142 png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5));
3143
3144 if (r == trans_values->red && g == trans_values->green &&
3145 b == trans_values->blue)
3146 {
3147 *sp = (png_byte)((background->red >> 8) & 0xff);
3148 *(sp + 1) = (png_byte)(background->red & 0xff);
3149 *(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
3150 *(sp + 3) = (png_byte)(background->green & 0xff);
3151 *(sp + 4) = (png_byte)((background->blue >> 8) & 0xff);
3152 *(sp + 5) = (png_byte)(background->blue & 0xff);
3153 }
3154 }
3155 }
3156 }
3157 break;
3158 }
3159
3160 case PNG_COLOR_TYPE_GRAY_ALPHA:
3161 {
3162 if (row_info->bit_depth == 8)
3163 {
3164 #ifdef PNG_READ_GAMMA_SUPPORTED
3165 if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
3166 gamma_table != NULL)
3167 {
3168 sp = row;
3169 dp = row;
3170 for (i = 0; i < row_width; i++, sp += 2, dp++)
3171 {
3172 png_uint_16 a = *(sp + 1);
3173
3174 if (a == 0xff)
3175 {
3176 *dp = gamma_table[*sp];
3177 }
3178 else if (a == 0)
3179 {
3180 /* Background is already in screen gamma */
3181 *dp = (png_byte)background->gray;
3182 }
3183 else
3184 {
3185 png_byte v, w;
3186
3187 v = gamma_to_1[*sp];
3188 png_composite(w, v, a, background_1->gray);
3189 *dp = gamma_from_1[w];
3190 }
3191 }
3192 }
3193 else
3194 #endif
3195 {
3196 sp = row;
3197 dp = row;
3198 for (i = 0; i < row_width; i++, sp += 2, dp++)
3199 {
3200 png_byte a = *(sp + 1);
3201
3202 if (a == 0xff)
3203 {
3204 *dp = *sp;
3205 }
3206 #ifdef PNG_READ_GAMMA_SUPPORTED
3207 else if (a == 0)
3208 {
3209 *dp = (png_byte)background->gray;
3210 }
3211 else
3212 {
3213 png_composite(*dp, *sp, a, background_1->gray);
3214 }
3215 #else
3216 *dp = (png_byte)background->gray;
3217 #endif
3218 }
3219 }
3220 }
3221 else /* if (png_ptr->bit_depth == 16) */
3222 {
3223 #ifdef PNG_READ_GAMMA_SUPPORTED
3224 if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
3225 gamma_16_to_1 != NULL)
3226 {
3227 sp = row;
3228 dp = row;
3229 for (i = 0; i < row_width; i++, sp += 4, dp += 2)
3230 {
3231 png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
3232
3233 if (a == (png_uint_16)0xffff)
3234 {
3235 png_uint_16 v;
3236
3237 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
3238 *dp = (png_byte)((v >> 8) & 0xff);
3239 *(dp + 1) = (png_byte)(v & 0xff);
3240 }
3241 #ifdef PNG_READ_GAMMA_SUPPORTED
3242 else if (a == 0)
3243 #else
3244 else
3245 #endif
3246 {
3247 /* Background is already in screen gamma */
3248 *dp = (png_byte)((background->gray >> 8) & 0xff);
3249 *(dp + 1) = (png_byte)(background->gray & 0xff);
3250 }
3251 #ifdef PNG_READ_GAMMA_SUPPORTED
3252 else
3253 {
3254 png_uint_16 g, v, w;
3255
3256 g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
3257 png_composite_16(v, g, a, background_1->gray);
3258 w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
3259 *dp = (png_byte)((w >> 8) & 0xff);
3260 *(dp + 1) = (png_byte)(w & 0xff);
3261 }
3262 #endif
3263 }
3264 }
3265 else
3266 #endif
3267 {
3268 sp = row;
3269 dp = row;
3270 for (i = 0; i < row_width; i++, sp += 4, dp += 2)
3271 {
3272 png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
3273 if (a == (png_uint_16)0xffff)
3274 {
3275 png_memcpy(dp, sp, 2);
3276 }
3277 #ifdef PNG_READ_GAMMA_SUPPORTED
3278 else if (a == 0)
3279 #else
3280 else
3281 #endif
3282 {
3283 *dp = (png_byte)((background->gray >> 8) & 0xff);
3284 *(dp + 1) = (png_byte)(background->gray & 0xff);
3285 }
3286 #ifdef PNG_READ_GAMMA_SUPPORTED
3287 else
3288 {
3289 png_uint_16 g, v;
3290
3291 g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3292 png_composite_16(v, g, a, background_1->gray);
3293 *dp = (png_byte)((v >> 8) & 0xff);
3294 *(dp + 1) = (png_byte)(v & 0xff);
3295 }
3296 #endif
3297 }
3298 }
3299 }
3300 break;
3301 }
3302
3303 case PNG_COLOR_TYPE_RGB_ALPHA:
3304 {
3305 if (row_info->bit_depth == 8)
3306 {
3307 #ifdef PNG_READ_GAMMA_SUPPORTED
3308 if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
3309 gamma_table != NULL)
3310 {
3311 sp = row;
3312 dp = row;
3313 for (i = 0; i < row_width; i++, sp += 4, dp += 3)
3314 {
3315 png_byte a = *(sp + 3);
3316
3317 if (a == 0xff)
3318 {
3319 *dp = gamma_table[*sp];
3320 *(dp + 1) = gamma_table[*(sp + 1)];
3321 *(dp + 2) = gamma_table[*(sp + 2)];
3322 }
3323 else if (a == 0)
3324 {
3325 /* Background is already in screen gamma */
3326 *dp = (png_byte)background->red;
3327 *(dp + 1) = (png_byte)background->green;
3328 *(dp + 2) = (png_byte)background->blue;
3329 }
3330 else
3331 {
3332 png_byte v, w;
3333
3334 v = gamma_to_1[*sp];
3335 png_composite(w, v, a, background_1->red);
3336 *dp = gamma_from_1[w];
3337 v = gamma_to_1[*(sp + 1)];
3338 png_composite(w, v, a, background_1->green);
3339 *(dp + 1) = gamma_from_1[w];
3340 v = gamma_to_1[*(sp + 2)];
3341 png_composite(w, v, a, background_1->blue);
3342 *(dp + 2) = gamma_from_1[w];
3343 }
3344 }
3345 }
3346 else
3347 #endif
3348 {
3349 sp = row;
3350 dp = row;
3351 for (i = 0; i < row_width; i++, sp += 4, dp += 3)
3352 {
3353 png_byte a = *(sp + 3);
3354
3355 if (a == 0xff)
3356 {
3357 *dp = *sp;
3358 *(dp + 1) = *(sp + 1);
3359 *(dp + 2) = *(sp + 2);
3360 }
3361 else if (a == 0)
3362 {
3363 *dp = (png_byte)background->red;
3364 *(dp + 1) = (png_byte)background->green;
3365 *(dp + 2) = (png_byte)background->blue;
3366 }
3367 else
3368 {
3369 png_composite(*dp, *sp, a, background->red);
3370 png_composite(*(dp + 1), *(sp + 1), a,
3371 background->green);
3372 png_composite(*(dp + 2), *(sp + 2), a,
3373 background->blue);
3374 }
3375 }
3376 }
3377 }
3378 else /* if (row_info->bit_depth == 16) */
3379 {
3380 #ifdef PNG_READ_GAMMA_SUPPORTED
3381 if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
3382 gamma_16_to_1 != NULL)
3383 {
3384 sp = row;
3385 dp = row;
3386 for (i = 0; i < row_width; i++, sp += 8, dp += 6)
3387 {
3388 png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
3389 << 8) + (png_uint_16)(*(sp + 7)));
3390 if (a == (png_uint_16)0xffff)
3391 {
3392 png_uint_16 v;
3393
3394 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
3395 *dp = (png_byte)((v >> 8) & 0xff);
3396 *(dp + 1) = (png_byte)(v & 0xff);
3397 v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
3398 *(dp + 2) = (png_byte)((v >> 8) & 0xff);
3399 *(dp + 3) = (png_byte)(v & 0xff);
3400 v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
3401 *(dp + 4) = (png_byte)((v >> 8) & 0xff);
3402 *(dp + 5) = (png_byte)(v & 0xff);
3403 }
3404 else if (a == 0)
3405 {
3406 /* Background is already in screen gamma */
3407 *dp = (png_byte)((background->red >> 8) & 0xff);
3408 *(dp + 1) = (png_byte)(background->red & 0xff);
3409 *(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
3410 *(dp + 3) = (png_byte)(background->green & 0xff);
3411 *(dp + 4) = (png_byte)((background->blue >> 8) & 0xff);
3412 *(dp + 5) = (png_byte)(background->blue & 0xff);
3413 }
3414 else
3415 {
3416 png_uint_16 v, w, x;
3417
3418 v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
3419 png_composite_16(w, v, a, background_1->red);
3420 x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
3421 *dp = (png_byte)((x >> 8) & 0xff);
3422 *(dp + 1) = (png_byte)(x & 0xff);
3423 v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
3424 png_composite_16(w, v, a, background_1->green);
3425 x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
3426 *(dp + 2) = (png_byte)((x >> 8) & 0xff);
3427 *(dp + 3) = (png_byte)(x & 0xff);
3428 v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
3429 png_composite_16(w, v, a, background_1->blue);
3430 x = gamma_16_from_1[(w & 0xff) >> gamma_shift][w >> 8];
3431 *(dp + 4) = (png_byte)((x >> 8) & 0xff);
3432 *(dp + 5) = (png_byte)(x & 0xff);
3433 }
3434 }
3435 }
3436 else
3437 #endif
3438 {
3439 sp = row;
3440 dp = row;
3441 for (i = 0; i < row_width; i++, sp += 8, dp += 6)
3442 {
3443 png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
3444 << 8) + (png_uint_16)(*(sp + 7)));
3445 if (a == (png_uint_16)0xffff)
3446 {
3447 png_memcpy(dp, sp, 6);
3448 }
3449 else if (a == 0)
3450 {
3451 *dp = (png_byte)((background->red >> 8) & 0xff);
3452 *(dp + 1) = (png_byte)(background->red & 0xff);
3453 *(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
3454 *(dp + 3) = (png_byte)(background->green & 0xff);
3455 *(dp + 4) = (png_byte)((background->blue >> 8) & 0xff);
3456 *(dp + 5) = (png_byte)(background->blue & 0xff);
3457 }
3458 else
3459 {
3460 png_uint_16 v;
3461
3462 png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3463 png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
3464 + *(sp + 3));
3465 png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
3466 + *(sp + 5));
3467
3468 png_composite_16(v, r, a, background->red);
3469 *dp = (png_byte)((v >> 8) & 0xff);
3470 *(dp + 1) = (png_byte)(v & 0xff);
3471 png_composite_16(v, g, a, background->green);
3472 *(dp + 2) = (png_byte)((v >> 8) & 0xff);
3473 *(dp + 3) = (png_byte)(v & 0xff);
3474 png_composite_16(v, b, a, background->blue);
3475 *(dp + 4) = (png_byte)((v >> 8) & 0xff);
3476 *(dp + 5) = (png_byte)(v & 0xff);
3477 }
3478 }
3479 }
3480 }
3481 break;
3482 }
3483 }
3484
3485 if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
3486 {
3487 row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;
3488 row_info->channels--;
3489 row_info->pixel_depth = (png_byte)(row_info->channels *
3490 row_info->bit_depth);
3491 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
3492 }
3493 }
3494 }
3495 #endif
3496
3497 #ifdef PNG_READ_GAMMA_SUPPORTED
3498 /* Gamma correct the image, avoiding the alpha channel. Make sure
3499 * you do this after you deal with the transparency issue on grayscale
3500 * or RGB images. If your bit depth is 8, use gamma_table, if it
3501 * is 16, use gamma_16_table and gamma_shift. Build these with
3502 * build_gamma_table().
3503 */
3504 void /* PRIVATE */
png_do_gamma(png_row_infop row_info,png_bytep row,png_bytep gamma_table,png_uint_16pp gamma_16_table,int gamma_shift)3505 png_do_gamma(png_row_infop row_info, png_bytep row,
3506 png_bytep gamma_table, png_uint_16pp gamma_16_table,
3507 int gamma_shift)
3508 {
3509 png_bytep sp;
3510 png_uint_32 i;
3511 png_uint_32 row_width=row_info->width;
3512
3513 png_debug(1, "in png_do_gamma");
3514
3515 if (
3516 #ifdef PNG_USELESS_TESTS_SUPPORTED
3517 row != NULL && row_info != NULL &&
3518 #endif
3519 ((row_info->bit_depth <= 8 && gamma_table != NULL) ||
3520 (row_info->bit_depth == 16 && gamma_16_table != NULL)))
3521 {
3522 switch (row_info->color_type)
3523 {
3524 case PNG_COLOR_TYPE_RGB:
3525 {
3526 if (row_info->bit_depth == 8)
3527 {
3528 sp = row;
3529 for (i = 0; i < row_width; i++)
3530 {
3531 *sp = gamma_table[*sp];
3532 sp++;
3533 *sp = gamma_table[*sp];
3534 sp++;
3535 *sp = gamma_table[*sp];
3536 sp++;
3537 }
3538 }
3539 else /* if (row_info->bit_depth == 16) */
3540 {
3541 sp = row;
3542 for (i = 0; i < row_width; i++)
3543 {
3544 png_uint_16 v;
3545
3546 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
3547 *sp = (png_byte)((v >> 8) & 0xff);
3548 *(sp + 1) = (png_byte)(v & 0xff);
3549 sp += 2;
3550 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
3551 *sp = (png_byte)((v >> 8) & 0xff);
3552 *(sp + 1) = (png_byte)(v & 0xff);
3553 sp += 2;
3554 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
3555 *sp = (png_byte)((v >> 8) & 0xff);
3556 *(sp + 1) = (png_byte)(v & 0xff);
3557 sp += 2;
3558 }
3559 }
3560 break;
3561 }
3562
3563 case PNG_COLOR_TYPE_RGB_ALPHA:
3564 {
3565 if (row_info->bit_depth == 8)
3566 {
3567 sp = row;
3568 for (i = 0; i < row_width; i++)
3569 {
3570 *sp = gamma_table[*sp];
3571 sp++;
3572 *sp = gamma_table[*sp];
3573 sp++;
3574 *sp = gamma_table[*sp];
3575 sp++;
3576 sp++;
3577 }
3578 }
3579 else /* if (row_info->bit_depth == 16) */
3580 {
3581 sp = row;
3582 for (i = 0; i < row_width; i++)
3583 {
3584 png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
3585 *sp = (png_byte)((v >> 8) & 0xff);
3586 *(sp + 1) = (png_byte)(v & 0xff);
3587 sp += 2;
3588 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
3589 *sp = (png_byte)((v >> 8) & 0xff);
3590 *(sp + 1) = (png_byte)(v & 0xff);
3591 sp += 2;
3592 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
3593 *sp = (png_byte)((v >> 8) & 0xff);
3594 *(sp + 1) = (png_byte)(v & 0xff);
3595 sp += 4;
3596 }
3597 }
3598 break;
3599 }
3600
3601 case PNG_COLOR_TYPE_GRAY_ALPHA:
3602 {
3603 if (row_info->bit_depth == 8)
3604 {
3605 sp = row;
3606 for (i = 0; i < row_width; i++)
3607 {
3608 *sp = gamma_table[*sp];
3609 sp += 2;
3610 }
3611 }
3612 else /* if (row_info->bit_depth == 16) */
3613 {
3614 sp = row;
3615 for (i = 0; i < row_width; i++)
3616 {
3617 png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
3618 *sp = (png_byte)((v >> 8) & 0xff);
3619 *(sp + 1) = (png_byte)(v & 0xff);
3620 sp += 4;
3621 }
3622 }
3623 break;
3624 }
3625
3626 case PNG_COLOR_TYPE_GRAY:
3627 {
3628 if (row_info->bit_depth == 2)
3629 {
3630 sp = row;
3631 for (i = 0; i < row_width; i += 4)
3632 {
3633 int a = *sp & 0xc0;
3634 int b = *sp & 0x30;
3635 int c = *sp & 0x0c;
3636 int d = *sp & 0x03;
3637
3638 *sp = (png_byte)(
3639 ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)]) ) & 0xc0)|
3640 ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
3641 ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
3642 ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
3643 sp++;
3644 }
3645 }
3646
3647 if (row_info->bit_depth == 4)
3648 {
3649 sp = row;
3650 for (i = 0; i < row_width; i += 2)
3651 {
3652 int msb = *sp & 0xf0;
3653 int lsb = *sp & 0x0f;
3654
3655 *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
3656 | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
3657 sp++;
3658 }
3659 }
3660
3661 else if (row_info->bit_depth == 8)
3662 {
3663 sp = row;
3664 for (i = 0; i < row_width; i++)
3665 {
3666 *sp = gamma_table[*sp];
3667 sp++;
3668 }
3669 }
3670
3671 else if (row_info->bit_depth == 16)
3672 {
3673 sp = row;
3674 for (i = 0; i < row_width; i++)
3675 {
3676 png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
3677 *sp = (png_byte)((v >> 8) & 0xff);
3678 *(sp + 1) = (png_byte)(v & 0xff);
3679 sp += 2;
3680 }
3681 }
3682 break;
3683 }
3684 }
3685 }
3686 }
3687 #endif
3688
3689 #ifdef PNG_READ_EXPAND_SUPPORTED
3690 /* Expands a palette row to an RGB or RGBA row depending
3691 * upon whether you supply trans and num_trans.
3692 */
3693 void /* PRIVATE */
png_do_expand_palette(png_row_infop row_info,png_bytep row,png_colorp palette,png_bytep trans,int num_trans)3694 png_do_expand_palette(png_row_infop row_info, png_bytep row,
3695 png_colorp palette, png_bytep trans, int num_trans)
3696 {
3697 int shift, value;
3698 png_bytep sp, dp;
3699 png_uint_32 i;
3700 png_uint_32 row_width=row_info->width;
3701
3702 png_debug(1, "in png_do_expand_palette");
3703
3704 if (
3705 #ifdef PNG_USELESS_TESTS_SUPPORTED
3706 row != NULL && row_info != NULL &&
3707 #endif
3708 row_info->color_type == PNG_COLOR_TYPE_PALETTE)
3709 {
3710 if (row_info->bit_depth < 8)
3711 {
3712 switch (row_info->bit_depth)
3713 {
3714 case 1:
3715 {
3716 sp = row + (png_size_t)((row_width - 1) >> 3);
3717 dp = row + (png_size_t)row_width - 1;
3718 shift = 7 - (int)((row_width + 7) & 0x07);
3719 for (i = 0; i < row_width; i++)
3720 {
3721 if ((*sp >> shift) & 0x01)
3722 *dp = 1;
3723 else
3724 *dp = 0;
3725 if (shift == 7)
3726 {
3727 shift = 0;
3728 sp--;
3729 }
3730 else
3731 shift++;
3732
3733 dp--;
3734 }
3735 break;
3736 }
3737
3738 case 2:
3739 {
3740 sp = row + (png_size_t)((row_width - 1) >> 2);
3741 dp = row + (png_size_t)row_width - 1;
3742 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
3743 for (i = 0; i < row_width; i++)
3744 {
3745 value = (*sp >> shift) & 0x03;
3746 *dp = (png_byte)value;
3747 if (shift == 6)
3748 {
3749 shift = 0;
3750 sp--;
3751 }
3752 else
3753 shift += 2;
3754
3755 dp--;
3756 }
3757 break;
3758 }
3759
3760 case 4:
3761 {
3762 sp = row + (png_size_t)((row_width - 1) >> 1);
3763 dp = row + (png_size_t)row_width - 1;
3764 shift = (int)((row_width & 0x01) << 2);
3765 for (i = 0; i < row_width; i++)
3766 {
3767 value = (*sp >> shift) & 0x0f;
3768 *dp = (png_byte)value;
3769 if (shift == 4)
3770 {
3771 shift = 0;
3772 sp--;
3773 }
3774 else
3775 shift += 4;
3776
3777 dp--;
3778 }
3779 break;
3780 }
3781 }
3782 row_info->bit_depth = 8;
3783 row_info->pixel_depth = 8;
3784 row_info->rowbytes = row_width;
3785 }
3786 switch (row_info->bit_depth)
3787 {
3788 case 8:
3789 {
3790 if (trans != NULL)
3791 {
3792 sp = row + (png_size_t)row_width - 1;
3793 dp = row + (png_size_t)(row_width << 2) - 1;
3794
3795 for (i = 0; i < row_width; i++)
3796 {
3797 if ((int)(*sp) >= num_trans)
3798 *dp-- = 0xff;
3799 else
3800 *dp-- = trans[*sp];
3801 *dp-- = palette[*sp].blue;
3802 *dp-- = palette[*sp].green;
3803 *dp-- = palette[*sp].red;
3804 sp--;
3805 }
3806 row_info->bit_depth = 8;
3807 row_info->pixel_depth = 32;
3808 row_info->rowbytes = row_width * 4;
3809 row_info->color_type = 6;
3810 row_info->channels = 4;
3811 }
3812 else
3813 {
3814 sp = row + (png_size_t)row_width - 1;
3815 dp = row + (png_size_t)(row_width * 3) - 1;
3816
3817 for (i = 0; i < row_width; i++)
3818 {
3819 *dp-- = palette[*sp].blue;
3820 *dp-- = palette[*sp].green;
3821 *dp-- = palette[*sp].red;
3822 sp--;
3823 }
3824
3825 row_info->bit_depth = 8;
3826 row_info->pixel_depth = 24;
3827 row_info->rowbytes = row_width * 3;
3828 row_info->color_type = 2;
3829 row_info->channels = 3;
3830 }
3831 break;
3832 }
3833 }
3834 }
3835 }
3836
3837 /* If the bit depth < 8, it is expanded to 8. Also, if the already
3838 * expanded transparency value is supplied, an alpha channel is built.
3839 */
3840 void /* PRIVATE */
png_do_expand(png_row_infop row_info,png_bytep row,png_color_16p trans_value)3841 png_do_expand(png_row_infop row_info, png_bytep row,
3842 png_color_16p trans_value)
3843 {
3844 int shift, value;
3845 png_bytep sp, dp;
3846 png_uint_32 i;
3847 png_uint_32 row_width=row_info->width;
3848
3849 png_debug(1, "in png_do_expand");
3850
3851 #ifdef PNG_USELESS_TESTS_SUPPORTED
3852 if (row != NULL && row_info != NULL)
3853 #endif
3854 {
3855 if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
3856 {
3857 png_uint_16 gray = (png_uint_16)(trans_value ? trans_value->gray : 0);
3858
3859 if (row_info->bit_depth < 8)
3860 {
3861 switch (row_info->bit_depth)
3862 {
3863 case 1:
3864 {
3865 gray = (png_uint_16)((gray&0x01)*0xff);
3866 sp = row + (png_size_t)((row_width - 1) >> 3);
3867 dp = row + (png_size_t)row_width - 1;
3868 shift = 7 - (int)((row_width + 7) & 0x07);
3869 for (i = 0; i < row_width; i++)
3870 {
3871 if ((*sp >> shift) & 0x01)
3872 *dp = 0xff;
3873 else
3874 *dp = 0;
3875 if (shift == 7)
3876 {
3877 shift = 0;
3878 sp--;
3879 }
3880 else
3881 shift++;
3882
3883 dp--;
3884 }
3885 break;
3886 }
3887
3888 case 2:
3889 {
3890 gray = (png_uint_16)((gray&0x03)*0x55);
3891 sp = row + (png_size_t)((row_width - 1) >> 2);
3892 dp = row + (png_size_t)row_width - 1;
3893 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
3894 for (i = 0; i < row_width; i++)
3895 {
3896 value = (*sp >> shift) & 0x03;
3897 *dp = (png_byte)(value | (value << 2) | (value << 4) |
3898 (value << 6));
3899 if (shift == 6)
3900 {
3901 shift = 0;
3902 sp--;
3903 }
3904 else
3905 shift += 2;
3906
3907 dp--;
3908 }
3909 break;
3910 }
3911
3912 case 4:
3913 {
3914 gray = (png_uint_16)((gray&0x0f)*0x11);
3915 sp = row + (png_size_t)((row_width - 1) >> 1);
3916 dp = row + (png_size_t)row_width - 1;
3917 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
3918 for (i = 0; i < row_width; i++)
3919 {
3920 value = (*sp >> shift) & 0x0f;
3921 *dp = (png_byte)(value | (value << 4));
3922 if (shift == 4)
3923 {
3924 shift = 0;
3925 sp--;
3926 }
3927 else
3928 shift = 4;
3929
3930 dp--;
3931 }
3932 break;
3933 }
3934 }
3935
3936 row_info->bit_depth = 8;
3937 row_info->pixel_depth = 8;
3938 row_info->rowbytes = row_width;
3939 }
3940
3941 if (trans_value != NULL)
3942 {
3943 if (row_info->bit_depth == 8)
3944 {
3945 gray = gray & 0xff;
3946 sp = row + (png_size_t)row_width - 1;
3947 dp = row + (png_size_t)(row_width << 1) - 1;
3948 for (i = 0; i < row_width; i++)
3949 {
3950 if (*sp == gray)
3951 *dp-- = 0;
3952 else
3953 *dp-- = 0xff;
3954 *dp-- = *sp--;
3955 }
3956 }
3957
3958 else if (row_info->bit_depth == 16)
3959 {
3960 png_byte gray_high = (gray >> 8) & 0xff;
3961 png_byte gray_low = gray & 0xff;
3962 sp = row + row_info->rowbytes - 1;
3963 dp = row + (row_info->rowbytes << 1) - 1;
3964 for (i = 0; i < row_width; i++)
3965 {
3966 if (*(sp - 1) == gray_high && *(sp) == gray_low)
3967 {
3968 *dp-- = 0;
3969 *dp-- = 0;
3970 }
3971 else
3972 {
3973 *dp-- = 0xff;
3974 *dp-- = 0xff;
3975 }
3976 *dp-- = *sp--;
3977 *dp-- = *sp--;
3978 }
3979 }
3980
3981 row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
3982 row_info->channels = 2;
3983 row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
3984 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
3985 row_width);
3986 }
3987 }
3988 else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_value)
3989 {
3990 if (row_info->bit_depth == 8)
3991 {
3992 png_byte red = trans_value->red & 0xff;
3993 png_byte green = trans_value->green & 0xff;
3994 png_byte blue = trans_value->blue & 0xff;
3995 sp = row + (png_size_t)row_info->rowbytes - 1;
3996 dp = row + (png_size_t)(row_width << 2) - 1;
3997 for (i = 0; i < row_width; i++)
3998 {
3999 if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
4000 *dp-- = 0;
4001 else
4002 *dp-- = 0xff;
4003 *dp-- = *sp--;
4004 *dp-- = *sp--;
4005 *dp-- = *sp--;
4006 }
4007 }
4008 else if (row_info->bit_depth == 16)
4009 {
4010 png_byte red_high = (trans_value->red >> 8) & 0xff;
4011 png_byte green_high = (trans_value->green >> 8) & 0xff;
4012 png_byte blue_high = (trans_value->blue >> 8) & 0xff;
4013 png_byte red_low = trans_value->red & 0xff;
4014 png_byte green_low = trans_value->green & 0xff;
4015 png_byte blue_low = trans_value->blue & 0xff;
4016 sp = row + row_info->rowbytes - 1;
4017 dp = row + (png_size_t)(row_width << 3) - 1;
4018 for (i = 0; i < row_width; i++)
4019 {
4020 if (*(sp - 5) == red_high &&
4021 *(sp - 4) == red_low &&
4022 *(sp - 3) == green_high &&
4023 *(sp - 2) == green_low &&
4024 *(sp - 1) == blue_high &&
4025 *(sp ) == blue_low)
4026 {
4027 *dp-- = 0;
4028 *dp-- = 0;
4029 }
4030 else
4031 {
4032 *dp-- = 0xff;
4033 *dp-- = 0xff;
4034 }
4035 *dp-- = *sp--;
4036 *dp-- = *sp--;
4037 *dp-- = *sp--;
4038 *dp-- = *sp--;
4039 *dp-- = *sp--;
4040 *dp-- = *sp--;
4041 }
4042 }
4043 row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
4044 row_info->channels = 4;
4045 row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
4046 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
4047 }
4048 }
4049 }
4050 #endif
4051
4052 #ifdef PNG_READ_DITHER_SUPPORTED
4053 void /* PRIVATE */
png_do_dither(png_row_infop row_info,png_bytep row,png_bytep palette_lookup,png_bytep dither_lookup)4054 png_do_dither(png_row_infop row_info, png_bytep row,
4055 png_bytep palette_lookup, png_bytep dither_lookup)
4056 {
4057 png_bytep sp, dp;
4058 png_uint_32 i;
4059 png_uint_32 row_width=row_info->width;
4060
4061 png_debug(1, "in png_do_dither");
4062
4063 #ifdef PNG_USELESS_TESTS_SUPPORTED
4064 if (row != NULL && row_info != NULL)
4065 #endif
4066 {
4067 if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
4068 palette_lookup && row_info->bit_depth == 8)
4069 {
4070 int r, g, b, p;
4071 sp = row;
4072 dp = row;
4073 for (i = 0; i < row_width; i++)
4074 {
4075 r = *sp++;
4076 g = *sp++;
4077 b = *sp++;
4078
4079 /* This looks real messy, but the compiler will reduce
4080 * it down to a reasonable formula. For example, with
4081 * 5 bits per color, we get:
4082 * p = (((r >> 3) & 0x1f) << 10) |
4083 * (((g >> 3) & 0x1f) << 5) |
4084 * ((b >> 3) & 0x1f);
4085 */
4086 p = (((r >> (8 - PNG_DITHER_RED_BITS)) &
4087 ((1 << PNG_DITHER_RED_BITS) - 1)) <<
4088 (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) |
4089 (((g >> (8 - PNG_DITHER_GREEN_BITS)) &
4090 ((1 << PNG_DITHER_GREEN_BITS) - 1)) <<
4091 (PNG_DITHER_BLUE_BITS)) |
4092 ((b >> (8 - PNG_DITHER_BLUE_BITS)) &
4093 ((1 << PNG_DITHER_BLUE_BITS) - 1));
4094
4095 *dp++ = palette_lookup[p];
4096 }
4097 row_info->color_type = PNG_COLOR_TYPE_PALETTE;
4098 row_info->channels = 1;
4099 row_info->pixel_depth = row_info->bit_depth;
4100 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
4101 }
4102 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
4103 palette_lookup != NULL && row_info->bit_depth == 8)
4104 {
4105 int r, g, b, p;
4106 sp = row;
4107 dp = row;
4108 for (i = 0; i < row_width; i++)
4109 {
4110 r = *sp++;
4111 g = *sp++;
4112 b = *sp++;
4113 sp++;
4114
4115 p = (((r >> (8 - PNG_DITHER_RED_BITS)) &
4116 ((1 << PNG_DITHER_RED_BITS) - 1)) <<
4117 (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) |
4118 (((g >> (8 - PNG_DITHER_GREEN_BITS)) &
4119 ((1 << PNG_DITHER_GREEN_BITS) - 1)) <<
4120 (PNG_DITHER_BLUE_BITS)) |
4121 ((b >> (8 - PNG_DITHER_BLUE_BITS)) &
4122 ((1 << PNG_DITHER_BLUE_BITS) - 1));
4123
4124 *dp++ = palette_lookup[p];
4125 }
4126 row_info->color_type = PNG_COLOR_TYPE_PALETTE;
4127 row_info->channels = 1;
4128 row_info->pixel_depth = row_info->bit_depth;
4129 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
4130 }
4131 else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
4132 dither_lookup && row_info->bit_depth == 8)
4133 {
4134 sp = row;
4135 for (i = 0; i < row_width; i++, sp++)
4136 {
4137 *sp = dither_lookup[*sp];
4138 }
4139 }
4140 }
4141 }
4142 #endif
4143
4144 #ifdef PNG_FLOATING_POINT_SUPPORTED
4145 #ifdef PNG_READ_GAMMA_SUPPORTED
4146 static PNG_CONST int png_gamma_shift[] =
4147 {0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0, 0x00};
4148
4149 /* We build the 8- or 16-bit gamma tables here. Note that for 16-bit
4150 * tables, we don't make a full table if we are reducing to 8-bit in
4151 * the future. Note also how the gamma_16 tables are segmented so that
4152 * we don't need to allocate > 64K chunks for a full 16-bit table.
4153 *
4154 * See the PNG extensions document for an integer algorithm for creating
4155 * the gamma tables. Maybe we will implement that here someday.
4156 *
4157 * We should only reach this point if
4158 *
4159 * the file_gamma is known (i.e., the gAMA or sRGB chunk is present,
4160 * or the application has provided a file_gamma)
4161 *
4162 * AND
4163 * {
4164 * the screen_gamma is known
4165 * OR
4166 *
4167 * RGB_to_gray transformation is being performed
4168 * }
4169 *
4170 * AND
4171 * {
4172 * the screen_gamma is different from the reciprocal of the
4173 * file_gamma by more than the specified threshold
4174 *
4175 * OR
4176 *
4177 * a background color has been specified and the file_gamma
4178 * and screen_gamma are not 1.0, within the specified threshold.
4179 * }
4180 */
4181
4182 void /* PRIVATE */
png_build_gamma_table(png_structp png_ptr)4183 png_build_gamma_table(png_structp png_ptr)
4184 {
4185 png_debug(1, "in png_build_gamma_table");
4186
4187 if (png_ptr->bit_depth <= 8)
4188 {
4189 int i;
4190 double g;
4191
4192 if (png_ptr->screen_gamma > .000001)
4193 g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
4194
4195 else
4196 g = 1.0;
4197
4198 png_ptr->gamma_table = (png_bytep)png_malloc(png_ptr,
4199 (png_uint_32)256);
4200
4201 for (i = 0; i < 256; i++)
4202 {
4203 png_ptr->gamma_table[i] = (png_byte)(pow((double)i / 255.0,
4204 g) * 255.0 + .5);
4205 }
4206
4207 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
4208 defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
4209 if (png_ptr->transformations & ((PNG_BACKGROUND) | PNG_RGB_TO_GRAY))
4210 {
4211
4212 g = 1.0 / (png_ptr->gamma);
4213
4214 png_ptr->gamma_to_1 = (png_bytep)png_malloc(png_ptr,
4215 (png_uint_32)256);
4216
4217 for (i = 0; i < 256; i++)
4218 {
4219 png_ptr->gamma_to_1[i] = (png_byte)(pow((double)i / 255.0,
4220 g) * 255.0 + .5);
4221 }
4222
4223
4224 png_ptr->gamma_from_1 = (png_bytep)png_malloc(png_ptr,
4225 (png_uint_32)256);
4226
4227 if (png_ptr->screen_gamma > 0.000001)
4228 g = 1.0 / png_ptr->screen_gamma;
4229
4230 else
4231 g = png_ptr->gamma; /* Probably doing rgb_to_gray */
4232
4233 for (i = 0; i < 256; i++)
4234 {
4235 png_ptr->gamma_from_1[i] = (png_byte)(pow((double)i / 255.0,
4236 g) * 255.0 + .5);
4237
4238 }
4239 }
4240 #endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
4241 }
4242 else
4243 {
4244 double g;
4245 int i, j, shift, num;
4246 int sig_bit;
4247 png_uint_32 ig;
4248
4249 if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
4250 {
4251 sig_bit = (int)png_ptr->sig_bit.red;
4252
4253 if ((int)png_ptr->sig_bit.green > sig_bit)
4254 sig_bit = png_ptr->sig_bit.green;
4255
4256 if ((int)png_ptr->sig_bit.blue > sig_bit)
4257 sig_bit = png_ptr->sig_bit.blue;
4258 }
4259 else
4260 {
4261 sig_bit = (int)png_ptr->sig_bit.gray;
4262 }
4263
4264 if (sig_bit > 0)
4265 shift = 16 - sig_bit;
4266
4267 else
4268 shift = 0;
4269
4270 if (png_ptr->transformations & PNG_16_TO_8)
4271 {
4272 if (shift < (16 - PNG_MAX_GAMMA_8))
4273 shift = (16 - PNG_MAX_GAMMA_8);
4274 }
4275
4276 if (shift > 8)
4277 shift = 8;
4278
4279 if (shift < 0)
4280 shift = 0;
4281
4282 png_ptr->gamma_shift = (png_byte)shift;
4283
4284 num = (1 << (8 - shift));
4285
4286 if (png_ptr->screen_gamma > .000001)
4287 g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
4288 else
4289 g = 1.0;
4290
4291 png_ptr->gamma_16_table = (png_uint_16pp)png_calloc(png_ptr,
4292 (png_uint_32)(num * png_sizeof(png_uint_16p)));
4293
4294 if (png_ptr->transformations & (PNG_16_TO_8 | PNG_BACKGROUND))
4295 {
4296 double fin, fout;
4297 png_uint_32 last, max;
4298
4299 for (i = 0; i < num; i++)
4300 {
4301 png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
4302 (png_uint_32)(256 * png_sizeof(png_uint_16)));
4303 }
4304
4305 g = 1.0 / g;
4306 last = 0;
4307 for (i = 0; i < 256; i++)
4308 {
4309 fout = ((double)i + 0.5) / 256.0;
4310 fin = pow(fout, g);
4311 max = (png_uint_32)(fin * (double)((png_uint_32)num << 8));
4312 while (last <= max)
4313 {
4314 png_ptr->gamma_16_table[(int)(last & (0xff >> shift))]
4315 [(int)(last >> (8 - shift))] = (png_uint_16)(
4316 (png_uint_16)i | ((png_uint_16)i << 8));
4317 last++;
4318 }
4319 }
4320 while (last < ((png_uint_32)num << 8))
4321 {
4322 png_ptr->gamma_16_table[(int)(last & (0xff >> shift))]
4323 [(int)(last >> (8 - shift))] = (png_uint_16)65535L;
4324 last++;
4325 }
4326 }
4327 else
4328 {
4329 for (i = 0; i < num; i++)
4330 {
4331 png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
4332 (png_uint_32)(256 * png_sizeof(png_uint_16)));
4333
4334 ig = (((png_uint_32)i * (png_uint_32)png_gamma_shift[shift]) >> 4);
4335
4336 for (j = 0; j < 256; j++)
4337 {
4338 png_ptr->gamma_16_table[i][j] =
4339 (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
4340 65535.0, g) * 65535.0 + .5);
4341 }
4342 }
4343 }
4344
4345 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
4346 defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
4347 if (png_ptr->transformations & (PNG_BACKGROUND | PNG_RGB_TO_GRAY))
4348 {
4349
4350 g = 1.0 / (png_ptr->gamma);
4351
4352 png_ptr->gamma_16_to_1 = (png_uint_16pp)png_calloc(png_ptr,
4353 (png_uint_32)(num * png_sizeof(png_uint_16p )));
4354
4355 for (i = 0; i < num; i++)
4356 {
4357 png_ptr->gamma_16_to_1[i] = (png_uint_16p)png_malloc(png_ptr,
4358 (png_uint_32)(256 * png_sizeof(png_uint_16)));
4359
4360 ig = (((png_uint_32)i *
4361 (png_uint_32)png_gamma_shift[shift]) >> 4);
4362 for (j = 0; j < 256; j++)
4363 {
4364 png_ptr->gamma_16_to_1[i][j] =
4365 (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
4366 65535.0, g) * 65535.0 + .5);
4367 }
4368 }
4369
4370 if (png_ptr->screen_gamma > 0.000001)
4371 g = 1.0 / png_ptr->screen_gamma;
4372
4373 else
4374 g = png_ptr->gamma; /* Probably doing rgb_to_gray */
4375
4376 png_ptr->gamma_16_from_1 = (png_uint_16pp)png_calloc(png_ptr,
4377 (png_uint_32)(num * png_sizeof(png_uint_16p)));
4378
4379 for (i = 0; i < num; i++)
4380 {
4381 png_ptr->gamma_16_from_1[i] = (png_uint_16p)png_malloc(png_ptr,
4382 (png_uint_32)(256 * png_sizeof(png_uint_16)));
4383
4384 ig = (((png_uint_32)i *
4385 (png_uint_32)png_gamma_shift[shift]) >> 4);
4386
4387 for (j = 0; j < 256; j++)
4388 {
4389 png_ptr->gamma_16_from_1[i][j] =
4390 (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
4391 65535.0, g) * 65535.0 + .5);
4392 }
4393 }
4394 }
4395 #endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
4396 }
4397 }
4398 #endif
4399 /* To do: install integer version of png_build_gamma_table here */
4400 #endif
4401
4402 #ifdef PNG_MNG_FEATURES_SUPPORTED
4403 /* Undoes intrapixel differencing */
4404 void /* PRIVATE */
png_do_read_intrapixel(png_row_infop row_info,png_bytep row)4405 png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
4406 {
4407 png_debug(1, "in png_do_read_intrapixel");
4408
4409 if (
4410 #ifdef PNG_USELESS_TESTS_SUPPORTED
4411 row != NULL && row_info != NULL &&
4412 #endif
4413 (row_info->color_type & PNG_COLOR_MASK_COLOR))
4414 {
4415 int bytes_per_pixel;
4416 png_uint_32 row_width = row_info->width;
4417 if (row_info->bit_depth == 8)
4418 {
4419 png_bytep rp;
4420 png_uint_32 i;
4421
4422 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
4423 bytes_per_pixel = 3;
4424
4425 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4426 bytes_per_pixel = 4;
4427
4428 else
4429 return;
4430
4431 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
4432 {
4433 *(rp) = (png_byte)((256 + *rp + *(rp+1))&0xff);
4434 *(rp+2) = (png_byte)((256 + *(rp+2) + *(rp+1))&0xff);
4435 }
4436 }
4437 else if (row_info->bit_depth == 16)
4438 {
4439 png_bytep rp;
4440 png_uint_32 i;
4441
4442 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
4443 bytes_per_pixel = 6;
4444
4445 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4446 bytes_per_pixel = 8;
4447
4448 else
4449 return;
4450
4451 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
4452 {
4453 png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
4454 png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
4455 png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
4456 png_uint_32 red = (png_uint_32)((s0 + s1 + 65536L) & 0xffffL);
4457 png_uint_32 blue = (png_uint_32)((s2 + s1 + 65536L) & 0xffffL);
4458 *(rp ) = (png_byte)((red >> 8) & 0xff);
4459 *(rp+1) = (png_byte)(red & 0xff);
4460 *(rp+4) = (png_byte)((blue >> 8) & 0xff);
4461 *(rp+5) = (png_byte)(blue & 0xff);
4462 }
4463 }
4464 }
4465 }
4466 #endif /* PNG_MNG_FEATURES_SUPPORTED */
4467 #endif /* PNG_READ_SUPPORTED */
4468