1 :
2 : /* pngrtran.c - transforms the data in a row for PNG readers
3 : *
4 : * Last changed in libpng 1.5.7 [December 15, 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 : #include "pngpriv.h"
20 :
21 : #ifdef PNG_READ_SUPPORTED
22 :
23 : /* Set the action on getting a CRC error for an ancillary or critical chunk. */
24 : void PNGAPI
25 4 : png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action)
26 : {
27 : png_debug(1, "in png_set_crc_action");
28 :
29 4 : if (png_ptr == NULL)
30 0 : return;
31 :
32 : /* Tell libpng how we react to CRC errors in critical chunks */
33 4 : switch (crit_action)
34 : {
35 : case PNG_CRC_NO_CHANGE: /* Leave setting as is */
36 4 : break;
37 :
38 : case PNG_CRC_WARN_USE: /* Warn/use data */
39 0 : png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
40 0 : png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
41 0 : break;
42 :
43 : case PNG_CRC_QUIET_USE: /* Quiet/use data */
44 0 : png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
45 0 : png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
46 : PNG_FLAG_CRC_CRITICAL_IGNORE;
47 0 : break;
48 :
49 : case PNG_CRC_WARN_DISCARD: /* Not a valid action for critical data */
50 : png_warning(png_ptr,
51 : "Can't discard critical data on CRC error");
52 : case PNG_CRC_ERROR_QUIT: /* Error/quit */
53 :
54 : case PNG_CRC_DEFAULT:
55 : default:
56 0 : png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
57 0 : break;
58 : }
59 :
60 : /* Tell libpng how we react to CRC errors in ancillary chunks */
61 4 : switch (ancil_action)
62 : {
63 : case PNG_CRC_NO_CHANGE: /* Leave setting as is */
64 0 : break;
65 :
66 : case PNG_CRC_WARN_USE: /* Warn/use data */
67 0 : png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
68 0 : png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
69 0 : break;
70 :
71 : case PNG_CRC_QUIET_USE: /* Quiet/use data */
72 0 : png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
73 0 : png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
74 : PNG_FLAG_CRC_ANCILLARY_NOWARN;
75 0 : break;
76 :
77 : case PNG_CRC_ERROR_QUIT: /* Error/quit */
78 4 : png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
79 4 : png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
80 4 : break;
81 :
82 : case PNG_CRC_WARN_DISCARD: /* Warn/discard data */
83 :
84 : case PNG_CRC_DEFAULT:
85 : default:
86 0 : png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
87 0 : break;
88 : }
89 : }
90 :
91 : #ifdef PNG_READ_BACKGROUND_SUPPORTED
92 : /* Handle alpha and tRNS via a background color */
93 : void PNGFAPI
94 : png_set_background_fixed(png_structp png_ptr,
95 : png_const_color_16p background_color, int background_gamma_code,
96 : int need_expand, png_fixed_point background_gamma)
97 : {
98 : png_debug(1, "in png_set_background_fixed");
99 :
100 : if (png_ptr == NULL)
101 : return;
102 :
103 : if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
104 : {
105 : png_warning(png_ptr, "Application must supply a known background gamma");
106 : return;
107 : }
108 :
109 : png_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA;
110 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
111 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
112 :
113 : png_memcpy(&(png_ptr->background), background_color,
114 : png_sizeof(png_color_16));
115 : png_ptr->background_gamma = background_gamma;
116 : png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
117 : if (need_expand)
118 : png_ptr->transformations |= PNG_BACKGROUND_EXPAND;
119 : else
120 : png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
121 : }
122 :
123 : # ifdef PNG_FLOATING_POINT_SUPPORTED
124 : void PNGAPI
125 : png_set_background(png_structp png_ptr,
126 : png_const_color_16p background_color, int background_gamma_code,
127 : int need_expand, double background_gamma)
128 : {
129 : png_set_background_fixed(png_ptr, background_color, background_gamma_code,
130 : need_expand, png_fixed(png_ptr, background_gamma, "png_set_background"));
131 : }
132 : # endif /* FLOATING_POINT */
133 : #endif /* READ_BACKGROUND */
134 :
135 : /* Scale 16-bit depth files to 8-bit depth. If both of these are set then the
136 : * one that pngrtran does first (scale) happens. This is necessary to allow the
137 : * TRANSFORM and API behavior to be somewhat consistent, and it's simpler.
138 : */
139 : #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
140 : void PNGAPI
141 0 : png_set_scale_16(png_structp png_ptr)
142 : {
143 : png_debug(1, "in png_set_scale_16");
144 :
145 0 : if (png_ptr == NULL)
146 0 : return;
147 :
148 0 : png_ptr->transformations |= PNG_SCALE_16_TO_8;
149 : }
150 : #endif
151 :
152 : #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
153 : /* Chop 16-bit depth files to 8-bit depth */
154 : void PNGAPI
155 : png_set_strip_16(png_structp png_ptr)
156 : {
157 : png_debug(1, "in png_set_strip_16");
158 :
159 : if (png_ptr == NULL)
160 : return;
161 :
162 : png_ptr->transformations |= PNG_16_TO_8;
163 : }
164 : #endif
165 :
166 : #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
167 : void PNGAPI
168 : png_set_strip_alpha(png_structp png_ptr)
169 : {
170 : png_debug(1, "in png_set_strip_alpha");
171 :
172 : if (png_ptr == NULL)
173 : return;
174 :
175 : png_ptr->transformations |= PNG_STRIP_ALPHA;
176 : }
177 : #endif
178 :
179 : #if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED)
180 : static png_fixed_point
181 8 : translate_gamma_flags(png_structp png_ptr, png_fixed_point output_gamma,
182 : int is_screen)
183 : {
184 : /* Check for flag values. The main reason for having the old Mac value as a
185 : * flag is that it is pretty near impossible to work out what the correct
186 : * value is from Apple documentation - a working Mac system is needed to
187 : * discover the value!
188 : */
189 8 : if (output_gamma == PNG_DEFAULT_sRGB ||
190 : output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB)
191 : {
192 : /* If there is no sRGB support this just sets the gamma to the standard
193 : * sRGB value. (This is a side effect of using this function!)
194 : */
195 : # ifdef PNG_READ_sRGB_SUPPORTED
196 0 : png_ptr->flags |= PNG_FLAG_ASSUME_sRGB;
197 : # endif
198 0 : if (is_screen)
199 0 : output_gamma = PNG_GAMMA_sRGB;
200 : else
201 0 : output_gamma = PNG_GAMMA_sRGB_INVERSE;
202 : }
203 :
204 8 : else if (output_gamma == PNG_GAMMA_MAC_18 ||
205 : output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18)
206 : {
207 0 : if (is_screen)
208 0 : output_gamma = PNG_GAMMA_MAC_OLD;
209 : else
210 0 : output_gamma = PNG_GAMMA_MAC_INVERSE;
211 : }
212 :
213 8 : return output_gamma;
214 : }
215 :
216 : # ifdef PNG_FLOATING_POINT_SUPPORTED
217 : static png_fixed_point
218 8 : convert_gamma_value(png_structp png_ptr, double output_gamma)
219 : {
220 : /* The following silently ignores cases where fixed point (times 100,000)
221 : * gamma values are passed to the floating point API. This is safe and it
222 : * means the fixed point constants work just fine with the floating point
223 : * API. The alternative would just lead to undetected errors and spurious
224 : * bug reports. Negative values fail inside the _fixed API unless they
225 : * correspond to the flag values.
226 : */
227 8 : if (output_gamma > 0 && output_gamma < 128)
228 8 : output_gamma *= PNG_FP_1;
229 :
230 : /* This preserves -1 and -2 exactly: */
231 8 : output_gamma = floor(output_gamma + .5);
232 :
233 8 : if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN)
234 0 : png_fixed_error(png_ptr, "gamma value");
235 :
236 8 : return (png_fixed_point)output_gamma;
237 : }
238 : # endif
239 : #endif /* READ_ALPHA_MODE || READ_GAMMA */
240 :
241 : #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
242 : void PNGFAPI
243 : png_set_alpha_mode_fixed(png_structp png_ptr, int mode,
244 : png_fixed_point output_gamma)
245 : {
246 : int compose = 0;
247 : png_fixed_point file_gamma;
248 :
249 : png_debug(1, "in png_set_alpha_mode");
250 :
251 : if (png_ptr == NULL)
252 : return;
253 :
254 : output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
255 :
256 : /* Validate the value to ensure it is in a reasonable range. The value
257 : * is expected to be 1 or greater, but this range test allows for some
258 : * viewing correction values. The intent is to weed out users of this API
259 : * who use the inverse of the gamma value accidentally! Since some of these
260 : * values are reasonable this may have to be changed.
261 : */
262 : if (output_gamma < 70000 || output_gamma > 300000)
263 : png_error(png_ptr, "output gamma out of expected range");
264 :
265 : /* The default file gamma is the inverse of the output gamma; the output
266 : * gamma may be changed below so get the file value first:
267 : */
268 : file_gamma = png_reciprocal(output_gamma);
269 :
270 : /* There are really 8 possibilities here, composed of any combination
271 : * of:
272 : *
273 : * premultiply the color channels
274 : * do not encode non-opaque pixels
275 : * encode the alpha as well as the color channels
276 : *
277 : * The differences disappear if the input/output ('screen') gamma is 1.0,
278 : * because then the encoding is a no-op and there is only the choice of
279 : * premultiplying the color channels or not.
280 : *
281 : * png_set_alpha_mode and png_set_background interact because both use
282 : * png_compose to do the work. Calling both is only useful when
283 : * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along
284 : * with a default gamma value. Otherwise PNG_COMPOSE must not be set.
285 : */
286 : switch (mode)
287 : {
288 : case PNG_ALPHA_PNG: /* default: png standard */
289 : /* No compose, but it may be set by png_set_background! */
290 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
291 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
292 : break;
293 :
294 : case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */
295 : compose = 1;
296 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
297 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
298 : /* The output is linear: */
299 : output_gamma = PNG_FP_1;
300 : break;
301 :
302 : case PNG_ALPHA_OPTIMIZED: /* associated, non-opaque pixels linear */
303 : compose = 1;
304 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
305 : png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA;
306 : /* output_gamma records the encoding of opaque pixels! */
307 : break;
308 :
309 : case PNG_ALPHA_BROKEN: /* associated, non-linear, alpha encoded */
310 : compose = 1;
311 : png_ptr->transformations |= PNG_ENCODE_ALPHA;
312 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
313 : break;
314 :
315 : default:
316 : png_error(png_ptr, "invalid alpha mode");
317 : }
318 :
319 : /* Only set the default gamma if the file gamma has not been set (this has
320 : * the side effect that the gamma in a second call to png_set_alpha_mode will
321 : * be ignored.)
322 : */
323 : if (png_ptr->gamma == 0)
324 : png_ptr->gamma = file_gamma;
325 :
326 : /* But always set the output gamma: */
327 : png_ptr->screen_gamma = output_gamma;
328 :
329 : /* Finally, if pre-multiplying, set the background fields to achieve the
330 : * desired result.
331 : */
332 : if (compose)
333 : {
334 : /* And obtain alpha pre-multiplication by composing on black: */
335 : png_memset(&png_ptr->background, 0, sizeof png_ptr->background);
336 : png_ptr->background_gamma = png_ptr->gamma; /* just in case */
337 : png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
338 : png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
339 :
340 : if (png_ptr->transformations & PNG_COMPOSE)
341 : png_error(png_ptr,
342 : "conflicting calls to set alpha mode and background");
343 :
344 : png_ptr->transformations |= PNG_COMPOSE;
345 : }
346 :
347 : /* New API, make sure apps call the correct initializers: */
348 : png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
349 : }
350 :
351 : # ifdef PNG_FLOATING_POINT_SUPPORTED
352 : void PNGAPI
353 : png_set_alpha_mode(png_structp png_ptr, int mode, double output_gamma)
354 : {
355 : png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr,
356 : output_gamma));
357 : }
358 : # endif
359 : #endif
360 :
361 : #ifdef PNG_READ_QUANTIZE_SUPPORTED
362 : /* Dither file to 8-bit. Supply a palette, the current number
363 : * of elements in the palette, the maximum number of elements
364 : * allowed, and a histogram if possible. If the current number
365 : * of colors is greater then the maximum number, the palette will be
366 : * modified to fit in the maximum number. "full_quantize" indicates
367 : * whether we need a quantizing cube set up for RGB images, or if we
368 : * simply are reducing the number of colors in a paletted image.
369 : */
370 :
371 : typedef struct png_dsort_struct
372 : {
373 : struct png_dsort_struct FAR * next;
374 : png_byte left;
375 : png_byte right;
376 : } png_dsort;
377 : typedef png_dsort FAR * png_dsortp;
378 : typedef png_dsort FAR * FAR * png_dsortpp;
379 :
380 : void PNGAPI
381 : png_set_quantize(png_structp png_ptr, png_colorp palette,
382 : int num_palette, int maximum_colors, png_const_uint_16p histogram,
383 : int full_quantize)
384 : {
385 : png_debug(1, "in png_set_quantize");
386 :
387 : if (png_ptr == NULL)
388 : return;
389 :
390 : png_ptr->transformations |= PNG_QUANTIZE;
391 :
392 : if (!full_quantize)
393 : {
394 : int i;
395 :
396 : png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr,
397 : (png_uint_32)(num_palette * png_sizeof(png_byte)));
398 : for (i = 0; i < num_palette; i++)
399 : png_ptr->quantize_index[i] = (png_byte)i;
400 : }
401 :
402 : if (num_palette > maximum_colors)
403 : {
404 : if (histogram != NULL)
405 : {
406 : /* This is easy enough, just throw out the least used colors.
407 : * Perhaps not the best solution, but good enough.
408 : */
409 :
410 : int i;
411 :
412 : /* Initialize an array to sort colors */
413 : png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr,
414 : (png_uint_32)(num_palette * png_sizeof(png_byte)));
415 :
416 : /* Initialize the quantize_sort array */
417 : for (i = 0; i < num_palette; i++)
418 : png_ptr->quantize_sort[i] = (png_byte)i;
419 :
420 : /* Find the least used palette entries by starting a
421 : * bubble sort, and running it until we have sorted
422 : * out enough colors. Note that we don't care about
423 : * sorting all the colors, just finding which are
424 : * least used.
425 : */
426 :
427 : for (i = num_palette - 1; i >= maximum_colors; i--)
428 : {
429 : int done; /* To stop early if the list is pre-sorted */
430 : int j;
431 :
432 : done = 1;
433 : for (j = 0; j < i; j++)
434 : {
435 : if (histogram[png_ptr->quantize_sort[j]]
436 : < histogram[png_ptr->quantize_sort[j + 1]])
437 : {
438 : png_byte t;
439 :
440 : t = png_ptr->quantize_sort[j];
441 : png_ptr->quantize_sort[j] = png_ptr->quantize_sort[j + 1];
442 : png_ptr->quantize_sort[j + 1] = t;
443 : done = 0;
444 : }
445 : }
446 :
447 : if (done)
448 : break;
449 : }
450 :
451 : /* Swap the palette around, and set up a table, if necessary */
452 : if (full_quantize)
453 : {
454 : int j = num_palette;
455 :
456 : /* Put all the useful colors within the max, but don't
457 : * move the others.
458 : */
459 : for (i = 0; i < maximum_colors; i++)
460 : {
461 : if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
462 : {
463 : do
464 : j--;
465 : while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
466 :
467 : palette[i] = palette[j];
468 : }
469 : }
470 : }
471 : else
472 : {
473 : int j = num_palette;
474 :
475 : /* Move all the used colors inside the max limit, and
476 : * develop a translation table.
477 : */
478 : for (i = 0; i < maximum_colors; i++)
479 : {
480 : /* Only move the colors we need to */
481 : if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
482 : {
483 : png_color tmp_color;
484 :
485 : do
486 : j--;
487 : while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
488 :
489 : tmp_color = palette[j];
490 : palette[j] = palette[i];
491 : palette[i] = tmp_color;
492 : /* Indicate where the color went */
493 : png_ptr->quantize_index[j] = (png_byte)i;
494 : png_ptr->quantize_index[i] = (png_byte)j;
495 : }
496 : }
497 :
498 : /* Find closest color for those colors we are not using */
499 : for (i = 0; i < num_palette; i++)
500 : {
501 : if ((int)png_ptr->quantize_index[i] >= maximum_colors)
502 : {
503 : int min_d, k, min_k, d_index;
504 :
505 : /* Find the closest color to one we threw out */
506 : d_index = png_ptr->quantize_index[i];
507 : min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
508 : for (k = 1, min_k = 0; k < maximum_colors; k++)
509 : {
510 : int d;
511 :
512 : d = PNG_COLOR_DIST(palette[d_index], palette[k]);
513 :
514 : if (d < min_d)
515 : {
516 : min_d = d;
517 : min_k = k;
518 : }
519 : }
520 : /* Point to closest color */
521 : png_ptr->quantize_index[i] = (png_byte)min_k;
522 : }
523 : }
524 : }
525 : png_free(png_ptr, png_ptr->quantize_sort);
526 : png_ptr->quantize_sort = NULL;
527 : }
528 : else
529 : {
530 : /* This is much harder to do simply (and quickly). Perhaps
531 : * we need to go through a median cut routine, but those
532 : * don't always behave themselves with only a few colors
533 : * as input. So we will just find the closest two colors,
534 : * and throw out one of them (chosen somewhat randomly).
535 : * [We don't understand this at all, so if someone wants to
536 : * work on improving it, be our guest - AED, GRP]
537 : */
538 : int i;
539 : int max_d;
540 : int num_new_palette;
541 : png_dsortp t;
542 : png_dsortpp hash;
543 :
544 : t = NULL;
545 :
546 : /* Initialize palette index arrays */
547 : png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
548 : (png_uint_32)(num_palette * png_sizeof(png_byte)));
549 : png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
550 : (png_uint_32)(num_palette * png_sizeof(png_byte)));
551 :
552 : /* Initialize the sort array */
553 : for (i = 0; i < num_palette; i++)
554 : {
555 : png_ptr->index_to_palette[i] = (png_byte)i;
556 : png_ptr->palette_to_index[i] = (png_byte)i;
557 : }
558 :
559 : hash = (png_dsortpp)png_calloc(png_ptr, (png_uint_32)(769 *
560 : png_sizeof(png_dsortp)));
561 :
562 : num_new_palette = num_palette;
563 :
564 : /* Initial wild guess at how far apart the farthest pixel
565 : * pair we will be eliminating will be. Larger
566 : * numbers mean more areas will be allocated, Smaller
567 : * numbers run the risk of not saving enough data, and
568 : * having to do this all over again.
569 : *
570 : * I have not done extensive checking on this number.
571 : */
572 : max_d = 96;
573 :
574 : while (num_new_palette > maximum_colors)
575 : {
576 : for (i = 0; i < num_new_palette - 1; i++)
577 : {
578 : int j;
579 :
580 : for (j = i + 1; j < num_new_palette; j++)
581 : {
582 : int d;
583 :
584 : d = PNG_COLOR_DIST(palette[i], palette[j]);
585 :
586 : if (d <= max_d)
587 : {
588 :
589 : t = (png_dsortp)png_malloc_warn(png_ptr,
590 : (png_uint_32)(png_sizeof(png_dsort)));
591 :
592 : if (t == NULL)
593 : break;
594 :
595 : t->next = hash[d];
596 : t->left = (png_byte)i;
597 : t->right = (png_byte)j;
598 : hash[d] = t;
599 : }
600 : }
601 : if (t == NULL)
602 : break;
603 : }
604 :
605 : if (t != NULL)
606 : for (i = 0; i <= max_d; i++)
607 : {
608 : if (hash[i] != NULL)
609 : {
610 : png_dsortp p;
611 :
612 : for (p = hash[i]; p; p = p->next)
613 : {
614 : if ((int)png_ptr->index_to_palette[p->left]
615 : < num_new_palette &&
616 : (int)png_ptr->index_to_palette[p->right]
617 : < num_new_palette)
618 : {
619 : int j, next_j;
620 :
621 : if (num_new_palette & 0x01)
622 : {
623 : j = p->left;
624 : next_j = p->right;
625 : }
626 : else
627 : {
628 : j = p->right;
629 : next_j = p->left;
630 : }
631 :
632 : num_new_palette--;
633 : palette[png_ptr->index_to_palette[j]]
634 : = palette[num_new_palette];
635 : if (!full_quantize)
636 : {
637 : int k;
638 :
639 : for (k = 0; k < num_palette; k++)
640 : {
641 : if (png_ptr->quantize_index[k] ==
642 : png_ptr->index_to_palette[j])
643 : png_ptr->quantize_index[k] =
644 : png_ptr->index_to_palette[next_j];
645 :
646 : if ((int)png_ptr->quantize_index[k] ==
647 : num_new_palette)
648 : png_ptr->quantize_index[k] =
649 : png_ptr->index_to_palette[j];
650 : }
651 : }
652 :
653 : png_ptr->index_to_palette[png_ptr->palette_to_index
654 : [num_new_palette]] = png_ptr->index_to_palette[j];
655 :
656 : png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
657 : = png_ptr->palette_to_index[num_new_palette];
658 :
659 : png_ptr->index_to_palette[j] =
660 : (png_byte)num_new_palette;
661 :
662 : png_ptr->palette_to_index[num_new_palette] =
663 : (png_byte)j;
664 : }
665 : if (num_new_palette <= maximum_colors)
666 : break;
667 : }
668 : if (num_new_palette <= maximum_colors)
669 : break;
670 : }
671 : }
672 :
673 : for (i = 0; i < 769; i++)
674 : {
675 : if (hash[i] != NULL)
676 : {
677 : png_dsortp p = hash[i];
678 : while (p)
679 : {
680 : t = p->next;
681 : png_free(png_ptr, p);
682 : p = t;
683 : }
684 : }
685 : hash[i] = 0;
686 : }
687 : max_d += 96;
688 : }
689 : png_free(png_ptr, hash);
690 : png_free(png_ptr, png_ptr->palette_to_index);
691 : png_free(png_ptr, png_ptr->index_to_palette);
692 : png_ptr->palette_to_index = NULL;
693 : png_ptr->index_to_palette = NULL;
694 : }
695 : num_palette = maximum_colors;
696 : }
697 : if (png_ptr->palette == NULL)
698 : {
699 : png_ptr->palette = palette;
700 : }
701 : png_ptr->num_palette = (png_uint_16)num_palette;
702 :
703 : if (full_quantize)
704 : {
705 : int i;
706 : png_bytep distance;
707 : int total_bits = PNG_QUANTIZE_RED_BITS + PNG_QUANTIZE_GREEN_BITS +
708 : PNG_QUANTIZE_BLUE_BITS;
709 : int num_red = (1 << PNG_QUANTIZE_RED_BITS);
710 : int num_green = (1 << PNG_QUANTIZE_GREEN_BITS);
711 : int num_blue = (1 << PNG_QUANTIZE_BLUE_BITS);
712 : png_size_t num_entries = ((png_size_t)1 << total_bits);
713 :
714 : png_ptr->palette_lookup = (png_bytep)png_calloc(png_ptr,
715 : (png_uint_32)(num_entries * png_sizeof(png_byte)));
716 :
717 : distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries *
718 : png_sizeof(png_byte)));
719 :
720 : png_memset(distance, 0xff, num_entries * png_sizeof(png_byte));
721 :
722 : for (i = 0; i < num_palette; i++)
723 : {
724 : int ir, ig, ib;
725 : int r = (palette[i].red >> (8 - PNG_QUANTIZE_RED_BITS));
726 : int g = (palette[i].green >> (8 - PNG_QUANTIZE_GREEN_BITS));
727 : int b = (palette[i].blue >> (8 - PNG_QUANTIZE_BLUE_BITS));
728 :
729 : for (ir = 0; ir < num_red; ir++)
730 : {
731 : /* int dr = abs(ir - r); */
732 : int dr = ((ir > r) ? ir - r : r - ir);
733 : int index_r = (ir << (PNG_QUANTIZE_BLUE_BITS +
734 : PNG_QUANTIZE_GREEN_BITS));
735 :
736 : for (ig = 0; ig < num_green; ig++)
737 : {
738 : /* int dg = abs(ig - g); */
739 : int dg = ((ig > g) ? ig - g : g - ig);
740 : int dt = dr + dg;
741 : int dm = ((dr > dg) ? dr : dg);
742 : int index_g = index_r | (ig << PNG_QUANTIZE_BLUE_BITS);
743 :
744 : for (ib = 0; ib < num_blue; ib++)
745 : {
746 : int d_index = index_g | ib;
747 : /* int db = abs(ib - b); */
748 : int db = ((ib > b) ? ib - b : b - ib);
749 : int dmax = ((dm > db) ? dm : db);
750 : int d = dmax + dt + db;
751 :
752 : if (d < (int)distance[d_index])
753 : {
754 : distance[d_index] = (png_byte)d;
755 : png_ptr->palette_lookup[d_index] = (png_byte)i;
756 : }
757 : }
758 : }
759 : }
760 : }
761 :
762 : png_free(png_ptr, distance);
763 : }
764 : }
765 : #endif /* PNG_READ_QUANTIZE_SUPPORTED */
766 :
767 : #ifdef PNG_READ_GAMMA_SUPPORTED
768 : void PNGFAPI
769 4 : png_set_gamma_fixed(png_structp png_ptr, png_fixed_point scrn_gamma,
770 : png_fixed_point file_gamma)
771 : {
772 : png_debug(1, "in png_set_gamma_fixed");
773 :
774 4 : if (png_ptr == NULL)
775 0 : return;
776 :
777 : /* New in libpng-1.5.4 - reserve particular negative values as flags. */
778 4 : scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/);
779 4 : file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/);
780 :
781 : #if PNG_LIBPNG_VER >= 10600
782 : /* Checking the gamma values for being >0 was added in 1.5.4 along with the
783 : * premultiplied alpha support; this actually hides an undocumented feature
784 : * of the previous implementation which allowed gamma processing to be
785 : * disabled in background handling. There is no evidence (so far) that this
786 : * was being used; however, png_set_background itself accepted and must still
787 : * accept '0' for the gamma value it takes, because it isn't always used.
788 : *
789 : * Since this is an API change (albeit a very minor one that removes an
790 : * undocumented API feature) it will not be made until libpng-1.6.0.
791 : */
792 : if (file_gamma <= 0)
793 : png_error(png_ptr, "invalid file gamma in png_set_gamma");
794 :
795 : if (scrn_gamma <= 0)
796 : png_error(png_ptr, "invalid screen gamma in png_set_gamma");
797 : #endif
798 :
799 : /* Set the gamma values unconditionally - this overrides the value in the PNG
800 : * file if a gAMA chunk was present. png_set_alpha_mode provides a
801 : * different, easier, way to default the file gamma.
802 : */
803 4 : png_ptr->gamma = file_gamma;
804 4 : png_ptr->screen_gamma = scrn_gamma;
805 : }
806 :
807 : # ifdef PNG_FLOATING_POINT_SUPPORTED
808 : void PNGAPI
809 4 : png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
810 : {
811 4 : png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma),
812 : convert_gamma_value(png_ptr, file_gamma));
813 4 : }
814 : # endif /* FLOATING_POINT_SUPPORTED */
815 : #endif /* READ_GAMMA */
816 :
817 : #ifdef PNG_READ_EXPAND_SUPPORTED
818 : /* Expand paletted images to RGB, expand grayscale images of
819 : * less than 8-bit depth to 8-bit depth, and expand tRNS chunks
820 : * to alpha channels.
821 : */
822 : void PNGAPI
823 0 : png_set_expand(png_structp png_ptr)
824 : {
825 : png_debug(1, "in png_set_expand");
826 :
827 0 : if (png_ptr == NULL)
828 0 : return;
829 :
830 0 : png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
831 0 : png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
832 : }
833 :
834 : /* GRR 19990627: the following three functions currently are identical
835 : * to png_set_expand(). However, it is entirely reasonable that someone
836 : * might wish to expand an indexed image to RGB but *not* expand a single,
837 : * fully transparent palette entry to a full alpha channel--perhaps instead
838 : * convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
839 : * the transparent color with a particular RGB value, or drop tRNS entirely.
840 : * IOW, a future version of the library may make the transformations flag
841 : * a bit more fine-grained, with separate bits for each of these three
842 : * functions.
843 : *
844 : * More to the point, these functions make it obvious what libpng will be
845 : * doing, whereas "expand" can (and does) mean any number of things.
846 : *
847 : * GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified
848 : * to expand only the sample depth but not to expand the tRNS to alpha
849 : * and its name was changed to png_set_expand_gray_1_2_4_to_8().
850 : */
851 :
852 : /* Expand paletted images to RGB. */
853 : void PNGAPI
854 0 : png_set_palette_to_rgb(png_structp png_ptr)
855 : {
856 : png_debug(1, "in png_set_palette_to_rgb");
857 :
858 0 : if (png_ptr == NULL)
859 0 : return;
860 :
861 0 : png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
862 0 : png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
863 : }
864 :
865 : /* Expand grayscale images of less than 8-bit depth to 8 bits. */
866 : void PNGAPI
867 4 : png_set_expand_gray_1_2_4_to_8(png_structp png_ptr)
868 : {
869 : png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
870 :
871 4 : if (png_ptr == NULL)
872 0 : return;
873 :
874 4 : png_ptr->transformations |= PNG_EXPAND;
875 4 : png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
876 : }
877 :
878 :
879 :
880 : /* Expand tRNS chunks to alpha channels. */
881 : void PNGAPI
882 0 : png_set_tRNS_to_alpha(png_structp png_ptr)
883 : {
884 : png_debug(1, "in png_set_tRNS_to_alpha");
885 :
886 0 : png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
887 0 : png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
888 0 : }
889 : #endif /* defined(PNG_READ_EXPAND_SUPPORTED) */
890 :
891 : #ifdef PNG_READ_EXPAND_16_SUPPORTED
892 : /* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise
893 : * it may not work correctly.)
894 : */
895 : void PNGAPI
896 : png_set_expand_16(png_structp png_ptr)
897 : {
898 : png_debug(1, "in png_set_expand_16");
899 :
900 : if (png_ptr == NULL)
901 : return;
902 :
903 : png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
904 : png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
905 :
906 : /* New API, make sure apps call the correct initializers: */
907 : png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
908 : }
909 : #endif
910 :
911 : #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
912 : void PNGAPI
913 4 : png_set_gray_to_rgb(png_structp png_ptr)
914 : {
915 : png_debug(1, "in png_set_gray_to_rgb");
916 :
917 4 : if (png_ptr != NULL)
918 : {
919 : /* Because rgb must be 8 bits or more: */
920 4 : png_set_expand_gray_1_2_4_to_8(png_ptr);
921 4 : png_ptr->transformations |= PNG_GRAY_TO_RGB;
922 4 : png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
923 : }
924 4 : }
925 : #endif
926 :
927 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
928 : void PNGFAPI
929 : png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action,
930 : png_fixed_point red, png_fixed_point green)
931 : {
932 : png_debug(1, "in png_set_rgb_to_gray");
933 :
934 : if (png_ptr == NULL)
935 : return;
936 :
937 : switch(error_action)
938 : {
939 : case PNG_ERROR_ACTION_NONE:
940 : png_ptr->transformations |= PNG_RGB_TO_GRAY;
941 : break;
942 :
943 : case PNG_ERROR_ACTION_WARN:
944 : png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
945 : break;
946 :
947 : case PNG_ERROR_ACTION_ERROR:
948 : png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
949 : break;
950 :
951 : default:
952 : png_error(png_ptr, "invalid error action to rgb_to_gray");
953 : break;
954 : }
955 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
956 : #ifdef PNG_READ_EXPAND_SUPPORTED
957 : png_ptr->transformations |= PNG_EXPAND;
958 : #else
959 : {
960 : png_warning(png_ptr,
961 : "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED");
962 :
963 : png_ptr->transformations &= ~PNG_RGB_TO_GRAY;
964 : }
965 : #endif
966 : {
967 : if (red >= 0 && green >= 0 && red + green <= PNG_FP_1)
968 : {
969 : png_uint_16 red_int, green_int;
970 :
971 : /* NOTE: this calculation does not round, but this behavior is retained
972 : * for consistency, the inaccuracy is very small. The code here always
973 : * overwrites the coefficients, regardless of whether they have been
974 : * defaulted or set already.
975 : */
976 : red_int = (png_uint_16)(((png_uint_32)red*32768)/100000);
977 : green_int = (png_uint_16)(((png_uint_32)green*32768)/100000);
978 :
979 : png_ptr->rgb_to_gray_red_coeff = red_int;
980 : png_ptr->rgb_to_gray_green_coeff = green_int;
981 : png_ptr->rgb_to_gray_coefficients_set = 1;
982 : }
983 :
984 : else
985 : {
986 : if (red >= 0 && green >= 0)
987 : png_warning(png_ptr,
988 : "ignoring out of range rgb_to_gray coefficients");
989 :
990 : /* Use the defaults, from the cHRM chunk if set, else the historical
991 : * values which are close to the sRGB/HDTV/ITU-Rec 709 values. See
992 : * png_do_rgb_to_gray for more discussion of the values. In this case
993 : * the coefficients are not marked as 'set' and are not overwritten if
994 : * something has already provided a default.
995 : */
996 : if (png_ptr->rgb_to_gray_red_coeff == 0 &&
997 : png_ptr->rgb_to_gray_green_coeff == 0)
998 : {
999 : png_ptr->rgb_to_gray_red_coeff = 6968;
1000 : png_ptr->rgb_to_gray_green_coeff = 23434;
1001 : /* png_ptr->rgb_to_gray_blue_coeff = 2366; */
1002 : }
1003 : }
1004 : }
1005 : }
1006 :
1007 : #ifdef PNG_FLOATING_POINT_SUPPORTED
1008 : /* Convert a RGB image to a grayscale of the same width. This allows us,
1009 : * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
1010 : */
1011 :
1012 : void PNGAPI
1013 : png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red,
1014 : double green)
1015 : {
1016 : if (png_ptr == NULL)
1017 : return;
1018 :
1019 : png_set_rgb_to_gray_fixed(png_ptr, error_action,
1020 : png_fixed(png_ptr, red, "rgb to gray red coefficient"),
1021 : png_fixed(png_ptr, green, "rgb to gray green coefficient"));
1022 : }
1023 : #endif /* FLOATING POINT */
1024 :
1025 : #endif
1026 :
1027 : #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
1028 : defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
1029 : void PNGAPI
1030 : png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
1031 : read_user_transform_fn)
1032 : {
1033 : png_debug(1, "in png_set_read_user_transform_fn");
1034 :
1035 : if (png_ptr == NULL)
1036 : return;
1037 :
1038 : #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1039 : png_ptr->transformations |= PNG_USER_TRANSFORM;
1040 : png_ptr->read_user_transform_fn = read_user_transform_fn;
1041 : #endif
1042 : }
1043 : #endif
1044 :
1045 : #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1046 : #ifdef PNG_READ_GAMMA_SUPPORTED
1047 : /* In the case of gamma transformations only do transformations on images where
1048 : * the [file] gamma and screen_gamma are not close reciprocals, otherwise it
1049 : * slows things down slightly, and also needlessly introduces small errors.
1050 : */
1051 : static int /* PRIVATE */
1052 4 : png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma)
1053 : {
1054 : /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
1055 : * correction as a difference of the overall transform from 1.0
1056 : *
1057 : * We want to compare the threshold with s*f - 1, if we get
1058 : * overflow here it is because of wacky gamma values so we
1059 : * turn on processing anyway.
1060 : */
1061 : png_fixed_point gtest;
1062 8 : return !png_muldiv(>est, screen_gamma, file_gamma, PNG_FP_1) ||
1063 4 : png_gamma_significant(gtest);
1064 : }
1065 : #endif
1066 :
1067 : /* Initialize everything needed for the read. This includes modifying
1068 : * the palette.
1069 : */
1070 :
1071 : /*For the moment 'png_init_palette_transformations' and
1072 : * 'png_init_rgb_transformations' only do some flag canceling optimizations.
1073 : * The intent is that these two routines should have palette or rgb operations
1074 : * extracted from 'png_init_read_transformations'.
1075 : */
1076 : static void /* PRIVATE */
1077 0 : png_init_palette_transformations(png_structp png_ptr)
1078 : {
1079 : /* Called to handle the (input) palette case. In png_do_read_transformations
1080 : * the first step is to expand the palette if requested, so this code must
1081 : * take care to only make changes that are invariant with respect to the
1082 : * palette expansion, or only do them if there is no expansion.
1083 : *
1084 : * STRIP_ALPHA has already been handled in the caller (by setting num_trans
1085 : * to 0.)
1086 : */
1087 0 : int input_has_alpha = 0;
1088 0 : int input_has_transparency = 0;
1089 :
1090 0 : if (png_ptr->num_trans > 0)
1091 : {
1092 : int i;
1093 :
1094 : /* Ignore if all the entries are opaque (unlikely!) */
1095 0 : for (i=0; i<png_ptr->num_trans; ++i)
1096 0 : if (png_ptr->trans_alpha[i] == 255)
1097 0 : continue;
1098 0 : else if (png_ptr->trans_alpha[i] == 0)
1099 0 : input_has_transparency = 1;
1100 : else
1101 0 : input_has_alpha = 1;
1102 : }
1103 :
1104 : /* If no alpha we can optimize. */
1105 0 : if (!input_has_alpha)
1106 : {
1107 : /* Any alpha means background and associative alpha processing is
1108 : * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA
1109 : * and ENCODE_ALPHA are irrelevant.
1110 : */
1111 0 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
1112 0 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
1113 :
1114 0 : if (!input_has_transparency)
1115 0 : png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
1116 : }
1117 :
1118 : #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
1119 : /* png_set_background handling - deals with the complexity of whether the
1120 : * background color is in the file format or the screen format in the case
1121 : * where an 'expand' will happen.
1122 : */
1123 :
1124 : /* The following code cannot be entered in the alpha pre-multiplication case
1125 : * because PNG_BACKGROUND_EXPAND is cancelled below.
1126 : */
1127 : if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
1128 : (png_ptr->transformations & PNG_EXPAND))
1129 : {
1130 : {
1131 : png_ptr->background.red =
1132 : png_ptr->palette[png_ptr->background.index].red;
1133 : png_ptr->background.green =
1134 : png_ptr->palette[png_ptr->background.index].green;
1135 : png_ptr->background.blue =
1136 : png_ptr->palette[png_ptr->background.index].blue;
1137 :
1138 : #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1139 : if (png_ptr->transformations & PNG_INVERT_ALPHA)
1140 : {
1141 : if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
1142 : {
1143 : /* Invert the alpha channel (in tRNS) unless the pixels are
1144 : * going to be expanded, in which case leave it for later
1145 : */
1146 : int i, istop = png_ptr->num_trans;
1147 :
1148 : for (i=0; i<istop; i++)
1149 : png_ptr->trans_alpha[i] = (png_byte)(255 -
1150 : png_ptr->trans_alpha[i]);
1151 : }
1152 : }
1153 : #endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */
1154 : }
1155 : } /* background expand and (therefore) no alpha association. */
1156 : #endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
1157 0 : }
1158 :
1159 : static void /* PRIVATE */
1160 4 : png_init_rgb_transformations(png_structp png_ptr)
1161 : {
1162 : /* Added to libpng-1.5.4: check the color type to determine whether there
1163 : * is any alpha or transparency in the image and simply cancel the
1164 : * background and alpha mode stuff if there isn't.
1165 : */
1166 4 : int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0;
1167 4 : int input_has_transparency = png_ptr->num_trans > 0;
1168 :
1169 : /* If no alpha we can optimize. */
1170 4 : if (!input_has_alpha)
1171 : {
1172 : /* Any alpha means background and associative alpha processing is
1173 : * required, however if the alpha is 0 or 1 throughout OPTIIMIZE_ALPHA
1174 : * and ENCODE_ALPHA are irrelevant.
1175 : */
1176 : # ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1177 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
1178 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
1179 : # endif
1180 :
1181 1 : if (!input_has_transparency)
1182 1 : png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
1183 : }
1184 :
1185 : #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
1186 : /* png_set_background handling - deals with the complexity of whether the
1187 : * background color is in the file format or the screen format in the case
1188 : * where an 'expand' will happen.
1189 : */
1190 :
1191 : /* The following code cannot be entered in the alpha pre-multiplication case
1192 : * because PNG_BACKGROUND_EXPAND is cancelled below.
1193 : */
1194 : if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
1195 : (png_ptr->transformations & PNG_EXPAND) &&
1196 : !(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
1197 : /* i.e., GRAY or GRAY_ALPHA */
1198 : {
1199 : {
1200 : /* Expand background and tRNS chunks */
1201 : int gray = png_ptr->background.gray;
1202 : int trans_gray = png_ptr->trans_color.gray;
1203 :
1204 : switch (png_ptr->bit_depth)
1205 : {
1206 : case 1:
1207 : gray *= 0xff;
1208 : trans_gray *= 0xff;
1209 : break;
1210 :
1211 : case 2:
1212 : gray *= 0x55;
1213 : trans_gray *= 0x55;
1214 : break;
1215 :
1216 : case 4:
1217 : gray *= 0x11;
1218 : trans_gray *= 0x11;
1219 : break;
1220 :
1221 : default:
1222 :
1223 : case 8:
1224 : /* Already 8 bits, fall through */
1225 :
1226 : case 16:
1227 : /* Already a full 16 bits */
1228 : break;
1229 : }
1230 :
1231 : png_ptr->background.red = png_ptr->background.green =
1232 : png_ptr->background.blue = (png_uint_16)gray;
1233 :
1234 : if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
1235 : {
1236 : png_ptr->trans_color.red = png_ptr->trans_color.green =
1237 : png_ptr->trans_color.blue = (png_uint_16)trans_gray;
1238 : }
1239 : }
1240 : } /* background expand and (therefore) no alpha association. */
1241 : #endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */
1242 4 : }
1243 :
1244 : void /* PRIVATE */
1245 4 : png_init_read_transformations(png_structp png_ptr)
1246 : {
1247 : png_debug(1, "in png_init_read_transformations");
1248 :
1249 : /* This internal function is called from png_read_start_row in pngrutil.c
1250 : * and it is called before the 'rowbytes' calculation is done, so the code
1251 : * in here can change or update the transformations flags.
1252 : *
1253 : * First do updates that do not depend on the details of the PNG image data
1254 : * being processed.
1255 : */
1256 :
1257 : #ifdef PNG_READ_GAMMA_SUPPORTED
1258 : /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds
1259 : * png_set_alpha_mode and this is another source for a default file gamma so
1260 : * the test needs to be performed later - here. In addition prior to 1.5.4
1261 : * the tests were repeated for the PALETTE color type here - this is no
1262 : * longer necessary (and doesn't seem to have been necessary before.)
1263 : */
1264 : {
1265 : /* The following temporary indicates if overall gamma correction is
1266 : * required.
1267 : */
1268 4 : int gamma_correction = 0;
1269 :
1270 4 : if (png_ptr->gamma != 0) /* has been set */
1271 : {
1272 4 : if (png_ptr->screen_gamma != 0) /* screen set too */
1273 4 : gamma_correction = png_gamma_threshold(png_ptr->gamma,
1274 : png_ptr->screen_gamma);
1275 :
1276 : else
1277 : /* Assume the output matches the input; a long time default behavior
1278 : * of libpng, although the standard has nothing to say about this.
1279 : */
1280 0 : png_ptr->screen_gamma = png_reciprocal(png_ptr->gamma);
1281 : }
1282 :
1283 0 : else if (png_ptr->screen_gamma != 0)
1284 : /* The converse - assume the file matches the screen, note that this
1285 : * perhaps undesireable default can (from 1.5.4) be changed by calling
1286 : * png_set_alpha_mode (even if the alpha handling mode isn't required
1287 : * or isn't changed from the default.)
1288 : */
1289 0 : png_ptr->gamma = png_reciprocal(png_ptr->screen_gamma);
1290 :
1291 : else /* neither are set */
1292 : /* Just in case the following prevents any processing - file and screen
1293 : * are both assumed to be linear and there is no way to introduce a
1294 : * third gamma value other than png_set_background with 'UNIQUE', and,
1295 : * prior to 1.5.4
1296 : */
1297 0 : png_ptr->screen_gamma = png_ptr->gamma = PNG_FP_1;
1298 :
1299 : /* Now turn the gamma transformation on or off as appropriate. Notice
1300 : * that PNG_GAMMA just refers to the file->screen correction. Alpha
1301 : * composition may independently cause gamma correction because it needs
1302 : * linear data (e.g. if the file has a gAMA chunk but the screen gamma
1303 : * hasn't been specified.) In any case this flag may get turned off in
1304 : * the code immediately below if the transform can be handled outside the
1305 : * row loop.
1306 : */
1307 4 : if (gamma_correction)
1308 0 : png_ptr->transformations |= PNG_GAMMA;
1309 :
1310 : else
1311 4 : png_ptr->transformations &= ~PNG_GAMMA;
1312 : }
1313 : #endif
1314 :
1315 : /* Certain transformations have the effect of preventing other
1316 : * transformations that happen afterward in png_do_read_transformations,
1317 : * resolve the interdependencies here. From the code of
1318 : * png_do_read_transformations the order is:
1319 : *
1320 : * 1) PNG_EXPAND (including PNG_EXPAND_tRNS)
1321 : * 2) PNG_STRIP_ALPHA (if no compose)
1322 : * 3) PNG_RGB_TO_GRAY
1323 : * 4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY
1324 : * 5) PNG_COMPOSE
1325 : * 6) PNG_GAMMA
1326 : * 7) PNG_STRIP_ALPHA (if compose)
1327 : * 8) PNG_ENCODE_ALPHA
1328 : * 9) PNG_SCALE_16_TO_8
1329 : * 10) PNG_16_TO_8
1330 : * 11) PNG_QUANTIZE (converts to palette)
1331 : * 12) PNG_EXPAND_16
1332 : * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY
1333 : * 14) PNG_INVERT_MONO
1334 : * 15) PNG_SHIFT
1335 : * 16) PNG_PACK
1336 : * 17) PNG_BGR
1337 : * 18) PNG_PACKSWAP
1338 : * 19) PNG_FILLER (includes PNG_ADD_ALPHA)
1339 : * 20) PNG_INVERT_ALPHA
1340 : * 21) PNG_SWAP_ALPHA
1341 : * 22) PNG_SWAP_BYTES
1342 : * 23) PNG_USER_TRANSFORM [must be last]
1343 : */
1344 : #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1345 : if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
1346 : !(png_ptr->transformations & PNG_COMPOSE))
1347 : {
1348 : /* Stripping the alpha channel happens immediately after the 'expand'
1349 : * transformations, before all other transformation, so it cancels out
1350 : * the alpha handling. It has the side effect negating the effect of
1351 : * PNG_EXPAND_tRNS too:
1352 : */
1353 : png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA |
1354 : PNG_EXPAND_tRNS);
1355 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
1356 :
1357 : /* Kill the tRNS chunk itself too. Prior to 1.5.4 this did not happen
1358 : * so transparency information would remain just so long as it wasn't
1359 : * expanded. This produces unexpected API changes if the set of things
1360 : * that do PNG_EXPAND_tRNS changes (perfectly possible given the
1361 : * documentation - which says ask for what you want, accept what you
1362 : * get.) This makes the behavior consistent from 1.5.4:
1363 : */
1364 : png_ptr->num_trans = 0;
1365 : }
1366 : #endif /* STRIP_ALPHA supported, no COMPOSE */
1367 :
1368 : #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1369 : /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
1370 : * settings will have no effect.
1371 : */
1372 : if (!png_gamma_significant(png_ptr->screen_gamma))
1373 : {
1374 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
1375 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
1376 : }
1377 : #endif
1378 :
1379 : #if defined(PNG_READ_EXPAND_SUPPORTED) && \
1380 : defined(PNG_READ_BACKGROUND_SUPPORTED) && \
1381 : defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
1382 : /* Detect gray background and attempt to enable optimization for
1383 : * gray --> RGB case.
1384 : *
1385 : * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
1386 : * RGB_ALPHA (in which case need_expand is superfluous anyway), the
1387 : * background color might actually be gray yet not be flagged as such.
1388 : * This is not a problem for the current code, which uses
1389 : * PNG_BACKGROUND_IS_GRAY only to decide when to do the
1390 : * png_do_gray_to_rgb() transformation.
1391 : *
1392 : * TODO: this code needs to be revised to avoid the complexity and
1393 : * interdependencies. The color type of the background should be recorded in
1394 : * png_set_background, along with the bit depth, then the code has a record
1395 : * of exactly what color space the background is currently in.
1396 : */
1397 : if (png_ptr->transformations & PNG_BACKGROUND_EXPAND)
1398 : {
1399 : /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
1400 : * the file was grayscale the background value is gray.
1401 : */
1402 : if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
1403 : png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
1404 : }
1405 :
1406 : else if (png_ptr->transformations & PNG_COMPOSE)
1407 : {
1408 : /* PNG_COMPOSE: png_set_background was called with need_expand false,
1409 : * so the color is in the color space of the output or png_set_alpha_mode
1410 : * was called and the color is black. Ignore RGB_TO_GRAY because that
1411 : * happens before GRAY_TO_RGB.
1412 : */
1413 : if (png_ptr->transformations & PNG_GRAY_TO_RGB)
1414 : {
1415 : if (png_ptr->background.red == png_ptr->background.green &&
1416 : png_ptr->background.red == png_ptr->background.blue)
1417 : {
1418 : png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
1419 : png_ptr->background.gray = png_ptr->background.red;
1420 : }
1421 : }
1422 : }
1423 : #endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED (etc) */
1424 :
1425 : /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations
1426 : * can be performed directly on the palette, and some (such as rgb to gray)
1427 : * can be optimized inside the palette. This is particularly true of the
1428 : * composite (background and alpha) stuff, which can be pretty much all done
1429 : * in the palette even if the result is expanded to RGB or gray afterward.
1430 : *
1431 : * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and
1432 : * earlier and the palette stuff is actually handled on the first row. This
1433 : * leads to the reported bug that the palette returned by png_get_PLTE is not
1434 : * updated.
1435 : */
1436 4 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1437 0 : png_init_palette_transformations(png_ptr);
1438 :
1439 : else
1440 4 : png_init_rgb_transformations(png_ptr);
1441 :
1442 : #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
1443 : defined(PNG_READ_EXPAND_16_SUPPORTED)
1444 : if ((png_ptr->transformations & PNG_EXPAND_16) &&
1445 : (png_ptr->transformations & PNG_COMPOSE) &&
1446 : !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
1447 : png_ptr->bit_depth != 16)
1448 : {
1449 : /* TODO: fix this. Because the expand_16 operation is after the compose
1450 : * handling the background color must be 8, not 16, bits deep, but the
1451 : * application will supply a 16-bit value so reduce it here.
1452 : *
1453 : * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at
1454 : * present, so that case is ok (until do_expand_16 is moved.)
1455 : *
1456 : * NOTE: this discards the low 16 bits of the user supplied background
1457 : * color, but until expand_16 works properly there is no choice!
1458 : */
1459 : # define CHOP(x) (x)=((png_uint_16)(((png_uint_32)(x)*255+32895) >> 16))
1460 : CHOP(png_ptr->background.red);
1461 : CHOP(png_ptr->background.green);
1462 : CHOP(png_ptr->background.blue);
1463 : CHOP(png_ptr->background.gray);
1464 : # undef CHOP
1465 : }
1466 : #endif /* PNG_READ_BACKGROUND_SUPPORTED && PNG_READ_EXPAND_16_SUPPORTED */
1467 :
1468 : #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
1469 : (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
1470 : defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
1471 : if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) &&
1472 : (png_ptr->transformations & PNG_COMPOSE) &&
1473 : !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
1474 : png_ptr->bit_depth == 16)
1475 : {
1476 : /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
1477 : * component this will also happen after PNG_COMPOSE and so the background
1478 : * color must be pre-expanded here.
1479 : *
1480 : * TODO: fix this too.
1481 : */
1482 : png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257);
1483 : png_ptr->background.green =
1484 : (png_uint_16)(png_ptr->background.green * 257);
1485 : png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257);
1486 : png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257);
1487 : }
1488 : #endif
1489 :
1490 : /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the
1491 : * background support (see the comments in scripts/pnglibconf.dfa), this
1492 : * allows pre-multiplication of the alpha channel to be implemented as
1493 : * compositing on black. This is probably sub-optimal and has been done in
1494 : * 1.5.4 betas simply to enable external critique and testing (i.e. to
1495 : * implement the new API quickly, without lots of internal changes.)
1496 : */
1497 :
1498 : #ifdef PNG_READ_GAMMA_SUPPORTED
1499 : # ifdef PNG_READ_BACKGROUND_SUPPORTED
1500 : /* Includes ALPHA_MODE */
1501 : png_ptr->background_1 = png_ptr->background;
1502 : # endif
1503 :
1504 : /* This needs to change - in the palette image case a whole set of tables are
1505 : * built when it would be quicker to just calculate the correct value for
1506 : * each palette entry directly. Also, the test is too tricky - why check
1507 : * PNG_RGB_TO_GRAY if PNG_GAMMA is not set? The answer seems to be that
1508 : * PNG_GAMMA is cancelled even if the gamma is known? The test excludes the
1509 : * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction
1510 : * the gamma tables will not be built even if composition is required on a
1511 : * gamma encoded value.
1512 : *
1513 : * In 1.5.4 this is addressed below by an additional check on the individual
1514 : * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
1515 : * tables.
1516 : */
1517 4 : if ((png_ptr->transformations & PNG_GAMMA)
1518 4 : || ((png_ptr->transformations & PNG_RGB_TO_GRAY)
1519 0 : && (png_gamma_significant(png_ptr->gamma) ||
1520 0 : png_gamma_significant(png_ptr->screen_gamma)))
1521 4 : || ((png_ptr->transformations & PNG_COMPOSE)
1522 0 : && (png_gamma_significant(png_ptr->gamma)
1523 0 : || png_gamma_significant(png_ptr->screen_gamma)
1524 : # ifdef PNG_READ_BACKGROUND_SUPPORTED
1525 : || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE
1526 : && png_gamma_significant(png_ptr->background_gamma))
1527 : # endif
1528 4 : )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA)
1529 0 : && png_gamma_significant(png_ptr->screen_gamma))
1530 : )
1531 : {
1532 0 : png_build_gamma_table(png_ptr, png_ptr->bit_depth);
1533 :
1534 : #ifdef PNG_READ_BACKGROUND_SUPPORTED
1535 : if (png_ptr->transformations & PNG_COMPOSE)
1536 : {
1537 : /* Issue a warning about this combination: because RGB_TO_GRAY is
1538 : * optimized to do the gamma transform if present yet do_background has
1539 : * to do the same thing if both options are set a
1540 : * double-gamma-correction happens. This is true in all versions of
1541 : * libpng to date.
1542 : */
1543 : if (png_ptr->transformations & PNG_RGB_TO_GRAY)
1544 : png_warning(png_ptr,
1545 : "libpng does not support gamma+background+rgb_to_gray");
1546 :
1547 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1548 : {
1549 : /* We don't get to here unless there is a tRNS chunk with non-opaque
1550 : * entries - see the checking code at the start of this function.
1551 : */
1552 : png_color back, back_1;
1553 : png_colorp palette = png_ptr->palette;
1554 : int num_palette = png_ptr->num_palette;
1555 : int i;
1556 : if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
1557 : {
1558 :
1559 : back.red = png_ptr->gamma_table[png_ptr->background.red];
1560 : back.green = png_ptr->gamma_table[png_ptr->background.green];
1561 : back.blue = png_ptr->gamma_table[png_ptr->background.blue];
1562 :
1563 : back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
1564 : back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
1565 : back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
1566 : }
1567 : else
1568 : {
1569 : png_fixed_point g, gs;
1570 :
1571 : switch (png_ptr->background_gamma_type)
1572 : {
1573 : case PNG_BACKGROUND_GAMMA_SCREEN:
1574 : g = (png_ptr->screen_gamma);
1575 : gs = PNG_FP_1;
1576 : break;
1577 :
1578 : case PNG_BACKGROUND_GAMMA_FILE:
1579 : g = png_reciprocal(png_ptr->gamma);
1580 : gs = png_reciprocal2(png_ptr->gamma,
1581 : png_ptr->screen_gamma);
1582 : break;
1583 :
1584 : case PNG_BACKGROUND_GAMMA_UNIQUE:
1585 : g = png_reciprocal(png_ptr->background_gamma);
1586 : gs = png_reciprocal2(png_ptr->background_gamma,
1587 : png_ptr->screen_gamma);
1588 : break;
1589 : default:
1590 : g = PNG_FP_1; /* back_1 */
1591 : gs = PNG_FP_1; /* back */
1592 : break;
1593 : }
1594 :
1595 : if (png_gamma_significant(gs))
1596 : {
1597 : back.red = png_gamma_8bit_correct(png_ptr->background.red,
1598 : gs);
1599 : back.green = png_gamma_8bit_correct(png_ptr->background.green,
1600 : gs);
1601 : back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
1602 : gs);
1603 : }
1604 :
1605 : else
1606 : {
1607 : back.red = (png_byte)png_ptr->background.red;
1608 : back.green = (png_byte)png_ptr->background.green;
1609 : back.blue = (png_byte)png_ptr->background.blue;
1610 : }
1611 :
1612 : if (png_gamma_significant(g))
1613 : {
1614 : back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
1615 : g);
1616 : back_1.green = png_gamma_8bit_correct(
1617 : png_ptr->background.green, g);
1618 : back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
1619 : g);
1620 : }
1621 :
1622 : else
1623 : {
1624 : back_1.red = (png_byte)png_ptr->background.red;
1625 : back_1.green = (png_byte)png_ptr->background.green;
1626 : back_1.blue = (png_byte)png_ptr->background.blue;
1627 : }
1628 : }
1629 :
1630 : for (i = 0; i < num_palette; i++)
1631 : {
1632 : if (i < (int)png_ptr->num_trans &&
1633 : png_ptr->trans_alpha[i] != 0xff)
1634 : {
1635 : if (png_ptr->trans_alpha[i] == 0)
1636 : {
1637 : palette[i] = back;
1638 : }
1639 : else /* if (png_ptr->trans_alpha[i] != 0xff) */
1640 : {
1641 : png_byte v, w;
1642 :
1643 : v = png_ptr->gamma_to_1[palette[i].red];
1644 : png_composite(w, v, png_ptr->trans_alpha[i], back_1.red);
1645 : palette[i].red = png_ptr->gamma_from_1[w];
1646 :
1647 : v = png_ptr->gamma_to_1[palette[i].green];
1648 : png_composite(w, v, png_ptr->trans_alpha[i], back_1.green);
1649 : palette[i].green = png_ptr->gamma_from_1[w];
1650 :
1651 : v = png_ptr->gamma_to_1[palette[i].blue];
1652 : png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue);
1653 : palette[i].blue = png_ptr->gamma_from_1[w];
1654 : }
1655 : }
1656 : else
1657 : {
1658 : palette[i].red = png_ptr->gamma_table[palette[i].red];
1659 : palette[i].green = png_ptr->gamma_table[palette[i].green];
1660 : palette[i].blue = png_ptr->gamma_table[palette[i].blue];
1661 : }
1662 : }
1663 :
1664 : /* Prevent the transformations being done again.
1665 : *
1666 : * NOTE: this is highly dubious; it removes the transformations in
1667 : * place. This seems inconsistent with the general treatment of the
1668 : * transformations elsewhere.
1669 : */
1670 : png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA);
1671 : } /* color_type == PNG_COLOR_TYPE_PALETTE */
1672 :
1673 : /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
1674 : else /* color_type != PNG_COLOR_TYPE_PALETTE */
1675 : {
1676 : int gs_sig, g_sig;
1677 : png_fixed_point g = PNG_FP_1; /* Correction to linear */
1678 : png_fixed_point gs = PNG_FP_1; /* Correction to screen */
1679 :
1680 : switch (png_ptr->background_gamma_type)
1681 : {
1682 : case PNG_BACKGROUND_GAMMA_SCREEN:
1683 : g = png_ptr->screen_gamma;
1684 : /* gs = PNG_FP_1; */
1685 : break;
1686 :
1687 : case PNG_BACKGROUND_GAMMA_FILE:
1688 : g = png_reciprocal(png_ptr->gamma);
1689 : gs = png_reciprocal2(png_ptr->gamma, png_ptr->screen_gamma);
1690 : break;
1691 :
1692 : case PNG_BACKGROUND_GAMMA_UNIQUE:
1693 : g = png_reciprocal(png_ptr->background_gamma);
1694 : gs = png_reciprocal2(png_ptr->background_gamma,
1695 : png_ptr->screen_gamma);
1696 : break;
1697 :
1698 : default:
1699 : png_error(png_ptr, "invalid background gamma type");
1700 : }
1701 :
1702 : g_sig = png_gamma_significant(g);
1703 : gs_sig = png_gamma_significant(gs);
1704 :
1705 : if (g_sig)
1706 : png_ptr->background_1.gray = png_gamma_correct(png_ptr,
1707 : png_ptr->background.gray, g);
1708 :
1709 : if (gs_sig)
1710 : png_ptr->background.gray = png_gamma_correct(png_ptr,
1711 : png_ptr->background.gray, gs);
1712 :
1713 : if ((png_ptr->background.red != png_ptr->background.green) ||
1714 : (png_ptr->background.red != png_ptr->background.blue) ||
1715 : (png_ptr->background.red != png_ptr->background.gray))
1716 : {
1717 : /* RGB or RGBA with color background */
1718 : if (g_sig)
1719 : {
1720 : png_ptr->background_1.red = png_gamma_correct(png_ptr,
1721 : png_ptr->background.red, g);
1722 :
1723 : png_ptr->background_1.green = png_gamma_correct(png_ptr,
1724 : png_ptr->background.green, g);
1725 :
1726 : png_ptr->background_1.blue = png_gamma_correct(png_ptr,
1727 : png_ptr->background.blue, g);
1728 : }
1729 :
1730 : if (gs_sig)
1731 : {
1732 : png_ptr->background.red = png_gamma_correct(png_ptr,
1733 : png_ptr->background.red, gs);
1734 :
1735 : png_ptr->background.green = png_gamma_correct(png_ptr,
1736 : png_ptr->background.green, gs);
1737 :
1738 : png_ptr->background.blue = png_gamma_correct(png_ptr,
1739 : png_ptr->background.blue, gs);
1740 : }
1741 : }
1742 :
1743 : else
1744 : {
1745 : /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
1746 : png_ptr->background_1.red = png_ptr->background_1.green
1747 : = png_ptr->background_1.blue = png_ptr->background_1.gray;
1748 :
1749 : png_ptr->background.red = png_ptr->background.green
1750 : = png_ptr->background.blue = png_ptr->background.gray;
1751 : }
1752 :
1753 : /* The background is now in screen gamma: */
1754 : png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN;
1755 : } /* color_type != PNG_COLOR_TYPE_PALETTE */
1756 : }/* png_ptr->transformations & PNG_BACKGROUND */
1757 :
1758 : else
1759 : /* Transformation does not include PNG_BACKGROUND */
1760 : #endif /* PNG_READ_BACKGROUND_SUPPORTED */
1761 0 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
1762 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1763 : /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
1764 : && ((png_ptr->transformations & PNG_EXPAND) == 0 ||
1765 : (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
1766 : #endif
1767 : )
1768 : {
1769 0 : png_colorp palette = png_ptr->palette;
1770 0 : int num_palette = png_ptr->num_palette;
1771 : int i;
1772 :
1773 : /*NOTE: there are other transformations that should probably be in here
1774 : * too.
1775 : */
1776 0 : for (i = 0; i < num_palette; i++)
1777 : {
1778 0 : palette[i].red = png_ptr->gamma_table[palette[i].red];
1779 0 : palette[i].green = png_ptr->gamma_table[palette[i].green];
1780 0 : palette[i].blue = png_ptr->gamma_table[palette[i].blue];
1781 : }
1782 :
1783 : /* Done the gamma correction. */
1784 0 : png_ptr->transformations &= ~PNG_GAMMA;
1785 : } /* color_type == PALETTE && !PNG_BACKGROUND transformation */
1786 : }
1787 : #ifdef PNG_READ_BACKGROUND_SUPPORTED
1788 : else
1789 : #endif
1790 : #endif /* PNG_READ_GAMMA_SUPPORTED */
1791 :
1792 : #ifdef PNG_READ_BACKGROUND_SUPPORTED
1793 : /* No GAMMA transformation (see the hanging else 4 lines above) */
1794 : if ((png_ptr->transformations & PNG_COMPOSE) &&
1795 : (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
1796 : {
1797 : int i;
1798 : int istop = (int)png_ptr->num_trans;
1799 : png_color back;
1800 : png_colorp palette = png_ptr->palette;
1801 :
1802 : back.red = (png_byte)png_ptr->background.red;
1803 : back.green = (png_byte)png_ptr->background.green;
1804 : back.blue = (png_byte)png_ptr->background.blue;
1805 :
1806 : for (i = 0; i < istop; i++)
1807 : {
1808 : if (png_ptr->trans_alpha[i] == 0)
1809 : {
1810 : palette[i] = back;
1811 : }
1812 :
1813 : else if (png_ptr->trans_alpha[i] != 0xff)
1814 : {
1815 : /* The png_composite() macro is defined in png.h */
1816 : png_composite(palette[i].red, palette[i].red,
1817 : png_ptr->trans_alpha[i], back.red);
1818 :
1819 : png_composite(palette[i].green, palette[i].green,
1820 : png_ptr->trans_alpha[i], back.green);
1821 :
1822 : png_composite(palette[i].blue, palette[i].blue,
1823 : png_ptr->trans_alpha[i], back.blue);
1824 : }
1825 : }
1826 :
1827 : png_ptr->transformations &= ~PNG_COMPOSE;
1828 : }
1829 : #endif /* PNG_READ_BACKGROUND_SUPPORTED */
1830 :
1831 : #ifdef PNG_READ_SHIFT_SUPPORTED
1832 : if ((png_ptr->transformations & PNG_SHIFT) &&
1833 : (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
1834 : {
1835 : int i;
1836 : int istop = png_ptr->num_palette;
1837 : int shift = 8 - png_ptr->sig_bit.red;
1838 :
1839 : /* significant bits can be in the range 1 to 7 for a meaninful result, if
1840 : * the number of significant bits is 0 then no shift is done (this is an
1841 : * error condition which is silently ignored.)
1842 : */
1843 : if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
1844 : {
1845 : int component = png_ptr->palette[i].red;
1846 :
1847 : component >>= shift;
1848 : png_ptr->palette[i].red = (png_byte)component;
1849 : }
1850 :
1851 : shift = 8 - png_ptr->sig_bit.green;
1852 : if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
1853 : {
1854 : int component = png_ptr->palette[i].green;
1855 :
1856 : component >>= shift;
1857 : png_ptr->palette[i].green = (png_byte)component;
1858 : }
1859 :
1860 : shift = 8 - png_ptr->sig_bit.blue;
1861 : if (shift > 0 && shift < 8) for (i=0; i<istop; ++i)
1862 : {
1863 : int component = png_ptr->palette[i].blue;
1864 :
1865 : component >>= shift;
1866 : png_ptr->palette[i].blue = (png_byte)component;
1867 : }
1868 : }
1869 : #endif /* PNG_READ_SHIFT_SUPPORTED */
1870 4 : }
1871 :
1872 : /* Modify the info structure to reflect the transformations. The
1873 : * info should be updated so a PNG file could be written with it,
1874 : * assuming the transformations result in valid PNG data.
1875 : */
1876 : void /* PRIVATE */
1877 4 : png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
1878 : {
1879 : png_debug(1, "in png_read_transform_info");
1880 :
1881 : #ifdef PNG_READ_EXPAND_SUPPORTED
1882 4 : if (png_ptr->transformations & PNG_EXPAND)
1883 : {
1884 4 : if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1885 : {
1886 : /* This check must match what actually happens in
1887 : * png_do_expand_palette; if it ever checks the tRNS chunk to see if
1888 : * it is all opaque we must do the same (at present it does not.)
1889 : */
1890 0 : if (png_ptr->num_trans > 0)
1891 0 : info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
1892 :
1893 : else
1894 0 : info_ptr->color_type = PNG_COLOR_TYPE_RGB;
1895 :
1896 0 : info_ptr->bit_depth = 8;
1897 0 : info_ptr->num_trans = 0;
1898 : }
1899 : else
1900 : {
1901 4 : if (png_ptr->num_trans)
1902 : {
1903 0 : if (png_ptr->transformations & PNG_EXPAND_tRNS)
1904 0 : info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
1905 : }
1906 4 : if (info_ptr->bit_depth < 8)
1907 0 : info_ptr->bit_depth = 8;
1908 :
1909 4 : info_ptr->num_trans = 0;
1910 : }
1911 : }
1912 : #endif
1913 :
1914 : #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
1915 : defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1916 : /* The following is almost certainly wrong unless the background value is in
1917 : * the screen space!
1918 : */
1919 : if (png_ptr->transformations & PNG_COMPOSE)
1920 : info_ptr->background = png_ptr->background;
1921 : #endif
1922 :
1923 : #ifdef PNG_READ_GAMMA_SUPPORTED
1924 : /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4),
1925 : * however it seems that the code in png_init_read_transformations, which has
1926 : * been called before this from png_read_update_info->png_read_start_row
1927 : * sometimes does the gamma transform and cancels the flag.
1928 : */
1929 4 : info_ptr->gamma = png_ptr->gamma;
1930 : #endif
1931 :
1932 4 : if (info_ptr->bit_depth == 16)
1933 : {
1934 : # ifdef PNG_READ_16BIT_SUPPORTED
1935 : # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1936 0 : if (png_ptr->transformations & PNG_SCALE_16_TO_8)
1937 0 : info_ptr->bit_depth = 8;
1938 : # endif
1939 :
1940 : # ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1941 : if (png_ptr->transformations & PNG_16_TO_8)
1942 : info_ptr->bit_depth = 8;
1943 : # endif
1944 :
1945 : # else
1946 : /* No 16 bit support: force chopping 16-bit input down to 8, in this case
1947 : * the app program can chose if both APIs are available by setting the
1948 : * correct scaling to use.
1949 : */
1950 : # ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1951 : /* For compatibility with previous versions use the strip method by
1952 : * default. This code works because if PNG_SCALE_16_TO_8 is already
1953 : * set the code below will do that in preference to the chop.
1954 : */
1955 : png_ptr->transformations |= PNG_16_TO_8;
1956 : info_ptr->bit_depth = 8;
1957 : # else
1958 :
1959 : # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1960 : png_ptr->transformations |= PNG_SCALE_16_TO_8;
1961 : info_ptr->bit_depth = 8;
1962 : # else
1963 :
1964 : CONFIGURATION ERROR: you must enable at least one 16 to 8 method
1965 : # endif
1966 : # endif
1967 : #endif /* !READ_16BIT_SUPPORTED */
1968 : }
1969 :
1970 : #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1971 4 : if (png_ptr->transformations & PNG_GRAY_TO_RGB)
1972 4 : info_ptr->color_type = (png_byte)(info_ptr->color_type |
1973 : PNG_COLOR_MASK_COLOR);
1974 : #endif
1975 :
1976 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1977 : if (png_ptr->transformations & PNG_RGB_TO_GRAY)
1978 : info_ptr->color_type = (png_byte)(info_ptr->color_type &
1979 : ~PNG_COLOR_MASK_COLOR);
1980 : #endif
1981 :
1982 : #ifdef PNG_READ_QUANTIZE_SUPPORTED
1983 : if (png_ptr->transformations & PNG_QUANTIZE)
1984 : {
1985 : if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
1986 : (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
1987 : png_ptr->palette_lookup && info_ptr->bit_depth == 8)
1988 : {
1989 : info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
1990 : }
1991 : }
1992 : #endif
1993 :
1994 : #ifdef PNG_READ_EXPAND_16_SUPPORTED
1995 : if (png_ptr->transformations & PNG_EXPAND_16 && info_ptr->bit_depth == 8 &&
1996 : info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
1997 : {
1998 : info_ptr->bit_depth = 16;
1999 : }
2000 : #endif
2001 :
2002 : #ifdef PNG_READ_PACK_SUPPORTED
2003 : if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
2004 : info_ptr->bit_depth = 8;
2005 : #endif
2006 :
2007 4 : if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
2008 0 : info_ptr->channels = 1;
2009 :
2010 4 : else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
2011 4 : info_ptr->channels = 3;
2012 :
2013 : else
2014 0 : info_ptr->channels = 1;
2015 :
2016 : #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
2017 : if (png_ptr->transformations & PNG_STRIP_ALPHA)
2018 : {
2019 : info_ptr->color_type = (png_byte)(info_ptr->color_type &
2020 : ~PNG_COLOR_MASK_ALPHA);
2021 : info_ptr->num_trans = 0;
2022 : }
2023 : #endif
2024 :
2025 4 : if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
2026 3 : info_ptr->channels++;
2027 :
2028 : #ifdef PNG_READ_FILLER_SUPPORTED
2029 : /* STRIP_ALPHA and FILLER allowed: MASK_ALPHA bit stripped above */
2030 : if ((png_ptr->transformations & PNG_FILLER) &&
2031 : ((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
2032 : (info_ptr->color_type == PNG_COLOR_TYPE_GRAY)))
2033 : {
2034 : info_ptr->channels++;
2035 : /* If adding a true alpha channel not just filler */
2036 : if (png_ptr->transformations & PNG_ADD_ALPHA)
2037 : info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
2038 : }
2039 : #endif
2040 :
2041 : #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
2042 : defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
2043 : if (png_ptr->transformations & PNG_USER_TRANSFORM)
2044 : {
2045 : if (info_ptr->bit_depth < png_ptr->user_transform_depth)
2046 : info_ptr->bit_depth = png_ptr->user_transform_depth;
2047 :
2048 : if (info_ptr->channels < png_ptr->user_transform_channels)
2049 : info_ptr->channels = png_ptr->user_transform_channels;
2050 : }
2051 : #endif
2052 :
2053 8 : info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
2054 4 : info_ptr->bit_depth);
2055 :
2056 4 : info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
2057 :
2058 : /* Adding in 1.5.4: cache the above value in png_struct so that we can later
2059 : * check in png_rowbytes that the user buffer won't get overwritten. Note
2060 : * that the field is not always set - if png_read_update_info isn't called
2061 : * the application has to either not do any transforms or get the calculation
2062 : * right itself.
2063 : */
2064 4 : png_ptr->info_rowbytes = info_ptr->rowbytes;
2065 :
2066 : #ifndef PNG_READ_EXPAND_SUPPORTED
2067 : if (png_ptr)
2068 : return;
2069 : #endif
2070 4 : }
2071 :
2072 : /* Transform the row. The order of transformations is significant,
2073 : * and is very touchy. If you add a transformation, take care to
2074 : * decide how it fits in with the other transformations here.
2075 : */
2076 : void /* PRIVATE */
2077 195 : png_do_read_transformations(png_structp png_ptr, png_row_infop row_info)
2078 : {
2079 : png_debug(1, "in png_do_read_transformations");
2080 :
2081 195 : if (png_ptr->row_buf == NULL)
2082 : {
2083 : /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
2084 : * error is incredibly rare and incredibly easy to debug without this
2085 : * information.
2086 : */
2087 0 : png_error(png_ptr, "NULL row buffer");
2088 : }
2089 :
2090 : /* The following is debugging; prior to 1.5.4 the code was never compiled in;
2091 : * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
2092 : * PNG_WARN_UNINITIALIZED_ROW removed. In 1.5 the new flag is set only for
2093 : * selected new APIs to ensure that there is no API change.
2094 : */
2095 195 : if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
2096 0 : !(png_ptr->flags & PNG_FLAG_ROW_INIT))
2097 : {
2098 : /* Application has failed to call either png_read_start_image() or
2099 : * png_read_update_info() after setting transforms that expand pixels.
2100 : * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
2101 : */
2102 0 : png_error(png_ptr, "Uninitialized row");
2103 : }
2104 :
2105 : #ifdef PNG_READ_EXPAND_SUPPORTED
2106 195 : if (png_ptr->transformations & PNG_EXPAND)
2107 : {
2108 195 : if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
2109 : {
2110 0 : png_do_expand_palette(row_info, png_ptr->row_buf + 1,
2111 0 : png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
2112 : }
2113 :
2114 : else
2115 : {
2116 195 : if (png_ptr->num_trans &&
2117 0 : (png_ptr->transformations & PNG_EXPAND_tRNS))
2118 0 : png_do_expand(row_info, png_ptr->row_buf + 1,
2119 0 : &(png_ptr->trans_color));
2120 :
2121 : else
2122 195 : png_do_expand(row_info, png_ptr->row_buf + 1,
2123 : NULL);
2124 : }
2125 : }
2126 : #endif
2127 :
2128 : #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
2129 : if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
2130 : !(png_ptr->transformations & PNG_COMPOSE) &&
2131 : (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
2132 : row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
2133 : png_do_strip_channel(row_info, png_ptr->row_buf + 1,
2134 : 0 /* at_start == false, because SWAP_ALPHA happens later */);
2135 : #endif
2136 :
2137 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2138 : if (png_ptr->transformations & PNG_RGB_TO_GRAY)
2139 : {
2140 : int rgb_error =
2141 : png_do_rgb_to_gray(png_ptr, row_info,
2142 : png_ptr->row_buf + 1);
2143 :
2144 : if (rgb_error)
2145 : {
2146 : png_ptr->rgb_to_gray_status=1;
2147 : if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
2148 : PNG_RGB_TO_GRAY_WARN)
2149 : png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
2150 :
2151 : if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
2152 : PNG_RGB_TO_GRAY_ERR)
2153 : png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
2154 : }
2155 : }
2156 : #endif
2157 :
2158 : /* From Andreas Dilger e-mail to png-implement, 26 March 1998:
2159 : *
2160 : * In most cases, the "simple transparency" should be done prior to doing
2161 : * gray-to-RGB, or you will have to test 3x as many bytes to check if a
2162 : * pixel is transparent. You would also need to make sure that the
2163 : * transparency information is upgraded to RGB.
2164 : *
2165 : * To summarize, the current flow is:
2166 : * - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
2167 : * with background "in place" if transparent,
2168 : * convert to RGB if necessary
2169 : * - Gray + alpha -> composite with gray background and remove alpha bytes,
2170 : * convert to RGB if necessary
2171 : *
2172 : * To support RGB backgrounds for gray images we need:
2173 : * - Gray + simple transparency -> convert to RGB + simple transparency,
2174 : * compare 3 or 6 bytes and composite with
2175 : * background "in place" if transparent
2176 : * (3x compare/pixel compared to doing
2177 : * composite with gray bkgrnd)
2178 : * - Gray + alpha -> convert to RGB + alpha, composite with background and
2179 : * remove alpha bytes (3x float
2180 : * operations/pixel compared with composite
2181 : * on gray background)
2182 : *
2183 : * Greg's change will do this. The reason it wasn't done before is for
2184 : * performance, as this increases the per-pixel operations. If we would check
2185 : * in advance if the background was gray or RGB, and position the gray-to-RGB
2186 : * transform appropriately, then it would save a lot of work/time.
2187 : */
2188 :
2189 : #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
2190 : /* If gray -> RGB, do so now only if background is non-gray; else do later
2191 : * for performance reasons
2192 : */
2193 390 : if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
2194 195 : !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
2195 195 : png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
2196 : #endif
2197 :
2198 : #if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
2199 : (defined PNG_READ_ALPHA_MODE_SUPPORTED)
2200 : if (png_ptr->transformations & PNG_COMPOSE)
2201 : png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
2202 : #endif
2203 :
2204 : #ifdef PNG_READ_GAMMA_SUPPORTED
2205 195 : if ((png_ptr->transformations & PNG_GAMMA) &&
2206 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2207 : /* Because RGB_TO_GRAY does the gamma transform. */
2208 : !(png_ptr->transformations & PNG_RGB_TO_GRAY) &&
2209 : #endif
2210 : #if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
2211 : (defined PNG_READ_ALPHA_MODE_SUPPORTED)
2212 : /* Because PNG_COMPOSE does the gamma transform if there is something to
2213 : * do (if there is an alpha channel or transparency.)
2214 : */
2215 : !((png_ptr->transformations & PNG_COMPOSE) &&
2216 : ((png_ptr->num_trans != 0) ||
2217 : (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
2218 : #endif
2219 : /* Because png_init_read_transformations transforms the palette, unless
2220 : * RGB_TO_GRAY will do the transform.
2221 : */
2222 0 : (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
2223 0 : png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
2224 : #endif
2225 :
2226 : #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
2227 : if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
2228 : (png_ptr->transformations & PNG_COMPOSE) &&
2229 : (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
2230 : row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
2231 : png_do_strip_channel(row_info, png_ptr->row_buf + 1,
2232 : 0 /* at_start == false, because SWAP_ALPHA happens later */);
2233 : #endif
2234 :
2235 : #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
2236 : if ((png_ptr->transformations & PNG_ENCODE_ALPHA) &&
2237 : (row_info->color_type & PNG_COLOR_MASK_ALPHA))
2238 : png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
2239 : #endif
2240 :
2241 : #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
2242 195 : if (png_ptr->transformations & PNG_SCALE_16_TO_8)
2243 0 : png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
2244 : #endif
2245 :
2246 : #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
2247 : /* There is no harm in doing both of these because only one has any effect,
2248 : * by putting the 'scale' option first if the app asks for scale (either by
2249 : * calling the API or in a TRANSFORM flag) this is what happens.
2250 : */
2251 : if (png_ptr->transformations & PNG_16_TO_8)
2252 : png_do_chop(row_info, png_ptr->row_buf + 1);
2253 : #endif
2254 :
2255 : #ifdef PNG_READ_QUANTIZE_SUPPORTED
2256 : if (png_ptr->transformations & PNG_QUANTIZE)
2257 : {
2258 : png_do_quantize(row_info, png_ptr->row_buf + 1,
2259 : png_ptr->palette_lookup, png_ptr->quantize_index);
2260 :
2261 : if (row_info->rowbytes == 0)
2262 : png_error(png_ptr, "png_do_quantize returned rowbytes=0");
2263 : }
2264 : #endif /* PNG_READ_QUANTIZE_SUPPORTED */
2265 :
2266 : #ifdef PNG_READ_EXPAND_16_SUPPORTED
2267 : /* Do the expansion now, after all the arithmetic has been done. Notice
2268 : * that previous transformations can handle the PNG_EXPAND_16 flag if this
2269 : * is efficient (particularly true in the case of gamma correction, where
2270 : * better accuracy results faster!)
2271 : */
2272 : if (png_ptr->transformations & PNG_EXPAND_16)
2273 : png_do_expand_16(row_info, png_ptr->row_buf + 1);
2274 : #endif
2275 :
2276 : #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
2277 : /*NOTE: moved here in 1.5.4 (from much later in this list.) */
2278 390 : if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
2279 195 : (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
2280 0 : png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
2281 : #endif
2282 :
2283 : #ifdef PNG_READ_INVERT_SUPPORTED
2284 : if (png_ptr->transformations & PNG_INVERT_MONO)
2285 : png_do_invert(row_info, png_ptr->row_buf + 1);
2286 : #endif
2287 :
2288 : #ifdef PNG_READ_SHIFT_SUPPORTED
2289 : if (png_ptr->transformations & PNG_SHIFT)
2290 : png_do_unshift(row_info, png_ptr->row_buf + 1,
2291 : &(png_ptr->shift));
2292 : #endif
2293 :
2294 : #ifdef PNG_READ_PACK_SUPPORTED
2295 : if (png_ptr->transformations & PNG_PACK)
2296 : png_do_unpack(row_info, png_ptr->row_buf + 1);
2297 : #endif
2298 :
2299 : #ifdef PNG_READ_BGR_SUPPORTED
2300 : if (png_ptr->transformations & PNG_BGR)
2301 : png_do_bgr(row_info, png_ptr->row_buf + 1);
2302 : #endif
2303 :
2304 : #ifdef PNG_READ_PACKSWAP_SUPPORTED
2305 : if (png_ptr->transformations & PNG_PACKSWAP)
2306 : png_do_packswap(row_info, png_ptr->row_buf + 1);
2307 : #endif
2308 :
2309 : #ifdef PNG_READ_FILLER_SUPPORTED
2310 : if (png_ptr->transformations & PNG_FILLER)
2311 : png_do_read_filler(row_info, png_ptr->row_buf + 1,
2312 : (png_uint_32)png_ptr->filler, png_ptr->flags);
2313 : #endif
2314 :
2315 : #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
2316 : if (png_ptr->transformations & PNG_INVERT_ALPHA)
2317 : png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
2318 : #endif
2319 :
2320 : #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
2321 : if (png_ptr->transformations & PNG_SWAP_ALPHA)
2322 : png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
2323 : #endif
2324 :
2325 : #ifdef PNG_READ_16BIT_SUPPORTED
2326 : #ifdef PNG_READ_SWAP_SUPPORTED
2327 : if (png_ptr->transformations & PNG_SWAP_BYTES)
2328 : png_do_swap(row_info, png_ptr->row_buf + 1);
2329 : #endif
2330 : #endif
2331 :
2332 : #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
2333 : if (png_ptr->transformations & PNG_USER_TRANSFORM)
2334 : {
2335 : if (png_ptr->read_user_transform_fn != NULL)
2336 : (*(png_ptr->read_user_transform_fn)) /* User read transform function */
2337 : (png_ptr, /* png_ptr */
2338 : row_info, /* row_info: */
2339 : /* png_uint_32 width; width of row */
2340 : /* png_size_t rowbytes; number of bytes in row */
2341 : /* png_byte color_type; color type of pixels */
2342 : /* png_byte bit_depth; bit depth of samples */
2343 : /* png_byte channels; number of channels (1-4) */
2344 : /* png_byte pixel_depth; bits per pixel (depth*channels) */
2345 : png_ptr->row_buf + 1); /* start of pixel data for row */
2346 : #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
2347 : if (png_ptr->user_transform_depth)
2348 : row_info->bit_depth = png_ptr->user_transform_depth;
2349 :
2350 : if (png_ptr->user_transform_channels)
2351 : row_info->channels = png_ptr->user_transform_channels;
2352 : #endif
2353 : row_info->pixel_depth = (png_byte)(row_info->bit_depth *
2354 : row_info->channels);
2355 :
2356 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
2357 : }
2358 : #endif
2359 195 : }
2360 :
2361 : #ifdef PNG_READ_PACK_SUPPORTED
2362 : /* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
2363 : * without changing the actual values. Thus, if you had a row with
2364 : * a bit depth of 1, you would end up with bytes that only contained
2365 : * the numbers 0 or 1. If you would rather they contain 0 and 255, use
2366 : * png_do_shift() after this.
2367 : */
2368 : void /* PRIVATE */
2369 : png_do_unpack(png_row_infop row_info, png_bytep row)
2370 : {
2371 : png_debug(1, "in png_do_unpack");
2372 :
2373 : if (row_info->bit_depth < 8)
2374 : {
2375 : png_uint_32 i;
2376 : png_uint_32 row_width=row_info->width;
2377 :
2378 : switch (row_info->bit_depth)
2379 : {
2380 : case 1:
2381 : {
2382 : png_bytep sp = row + (png_size_t)((row_width - 1) >> 3);
2383 : png_bytep dp = row + (png_size_t)row_width - 1;
2384 : png_uint_32 shift = 7 - (int)((row_width + 7) & 0x07);
2385 : for (i = 0; i < row_width; i++)
2386 : {
2387 : *dp = (png_byte)((*sp >> shift) & 0x01);
2388 :
2389 : if (shift == 7)
2390 : {
2391 : shift = 0;
2392 : sp--;
2393 : }
2394 :
2395 : else
2396 : shift++;
2397 :
2398 : dp--;
2399 : }
2400 : break;
2401 : }
2402 :
2403 : case 2:
2404 : {
2405 :
2406 : png_bytep sp = row + (png_size_t)((row_width - 1) >> 2);
2407 : png_bytep dp = row + (png_size_t)row_width - 1;
2408 : png_uint_32 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
2409 : for (i = 0; i < row_width; i++)
2410 : {
2411 : *dp = (png_byte)((*sp >> shift) & 0x03);
2412 :
2413 : if (shift == 6)
2414 : {
2415 : shift = 0;
2416 : sp--;
2417 : }
2418 :
2419 : else
2420 : shift += 2;
2421 :
2422 : dp--;
2423 : }
2424 : break;
2425 : }
2426 :
2427 : case 4:
2428 : {
2429 : png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
2430 : png_bytep dp = row + (png_size_t)row_width - 1;
2431 : png_uint_32 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
2432 : for (i = 0; i < row_width; i++)
2433 : {
2434 : *dp = (png_byte)((*sp >> shift) & 0x0f);
2435 :
2436 : if (shift == 4)
2437 : {
2438 : shift = 0;
2439 : sp--;
2440 : }
2441 :
2442 : else
2443 : shift = 4;
2444 :
2445 : dp--;
2446 : }
2447 : break;
2448 : }
2449 :
2450 : default:
2451 : break;
2452 : }
2453 : row_info->bit_depth = 8;
2454 : row_info->pixel_depth = (png_byte)(8 * row_info->channels);
2455 : row_info->rowbytes = row_width * row_info->channels;
2456 : }
2457 : }
2458 : #endif
2459 :
2460 : #ifdef PNG_READ_SHIFT_SUPPORTED
2461 : /* Reverse the effects of png_do_shift. This routine merely shifts the
2462 : * pixels back to their significant bits values. Thus, if you have
2463 : * a row of bit depth 8, but only 5 are significant, this will shift
2464 : * the values back to 0 through 31.
2465 : */
2466 : void /* PRIVATE */
2467 : png_do_unshift(png_row_infop row_info, png_bytep row,
2468 : png_const_color_8p sig_bits)
2469 : {
2470 : int color_type;
2471 :
2472 : png_debug(1, "in png_do_unshift");
2473 :
2474 : /* The palette case has already been handled in the _init routine. */
2475 : color_type = row_info->color_type;
2476 :
2477 : if (color_type != PNG_COLOR_TYPE_PALETTE)
2478 : {
2479 : int shift[4];
2480 : int channels = 0;
2481 : int bit_depth = row_info->bit_depth;
2482 :
2483 : if (color_type & PNG_COLOR_MASK_COLOR)
2484 : {
2485 : shift[channels++] = bit_depth - sig_bits->red;
2486 : shift[channels++] = bit_depth - sig_bits->green;
2487 : shift[channels++] = bit_depth - sig_bits->blue;
2488 : }
2489 :
2490 : else
2491 : {
2492 : shift[channels++] = bit_depth - sig_bits->gray;
2493 : }
2494 :
2495 : if (color_type & PNG_COLOR_MASK_ALPHA)
2496 : {
2497 : shift[channels++] = bit_depth - sig_bits->alpha;
2498 : }
2499 :
2500 : {
2501 : int c, have_shift;
2502 :
2503 : for (c = have_shift = 0; c < channels; ++c)
2504 : {
2505 : /* A shift of more than the bit depth is an error condition but it
2506 : * gets ignored here.
2507 : */
2508 : if (shift[c] <= 0 || shift[c] >= bit_depth)
2509 : shift[c] = 0;
2510 :
2511 : else
2512 : have_shift = 1;
2513 : }
2514 :
2515 : if (!have_shift)
2516 : return;
2517 : }
2518 :
2519 : switch (bit_depth)
2520 : {
2521 : default:
2522 : /* Must be 1bpp gray: should not be here! */
2523 : /* NOTREACHED */
2524 : break;
2525 :
2526 : case 2:
2527 : /* Must be 2bpp gray */
2528 : /* assert(channels == 1 && shift[0] == 1) */
2529 : {
2530 : png_bytep bp = row;
2531 : png_bytep bp_end = bp + row_info->rowbytes;
2532 :
2533 : while (bp < bp_end)
2534 : {
2535 : int b = (*bp >> 1) & 0x55;
2536 : *bp++ = (png_byte)b;
2537 : }
2538 : break;
2539 : }
2540 :
2541 : case 4:
2542 : /* Must be 4bpp gray */
2543 : /* assert(channels == 1) */
2544 : {
2545 : png_bytep bp = row;
2546 : png_bytep bp_end = bp + row_info->rowbytes;
2547 : int gray_shift = shift[0];
2548 : int mask = 0xf >> gray_shift;
2549 :
2550 : mask |= mask << 4;
2551 :
2552 : while (bp < bp_end)
2553 : {
2554 : int b = (*bp >> gray_shift) & mask;
2555 : *bp++ = (png_byte)b;
2556 : }
2557 : break;
2558 : }
2559 :
2560 : case 8:
2561 : /* Single byte components, G, GA, RGB, RGBA */
2562 : {
2563 : png_bytep bp = row;
2564 : png_bytep bp_end = bp + row_info->rowbytes;
2565 : int channel = 0;
2566 :
2567 : while (bp < bp_end)
2568 : {
2569 : int b = *bp >> shift[channel];
2570 : if (++channel >= channels)
2571 : channel = 0;
2572 : *bp++ = (png_byte)b;
2573 : }
2574 : break;
2575 : }
2576 :
2577 : #ifdef PNG_READ_16BIT_SUPPORTED
2578 : case 16:
2579 : /* Double byte components, G, GA, RGB, RGBA */
2580 : {
2581 : png_bytep bp = row;
2582 : png_bytep bp_end = bp + row_info->rowbytes;
2583 : int channel = 0;
2584 :
2585 : while (bp < bp_end)
2586 : {
2587 : int value = (bp[0] << 8) + bp[1];
2588 :
2589 : value >>= shift[channel];
2590 : if (++channel >= channels)
2591 : channel = 0;
2592 : *bp++ = (png_byte)(value >> 8);
2593 : *bp++ = (png_byte)(value & 0xff);
2594 : }
2595 : break;
2596 : }
2597 : #endif
2598 : }
2599 : }
2600 : }
2601 : #endif
2602 :
2603 : #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
2604 : /* Scale rows of bit depth 16 down to 8 accurately */
2605 : void /* PRIVATE */
2606 0 : png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
2607 : {
2608 : png_debug(1, "in png_do_scale_16_to_8");
2609 :
2610 0 : if (row_info->bit_depth == 16)
2611 : {
2612 0 : png_bytep sp = row; /* source */
2613 0 : png_bytep dp = row; /* destination */
2614 0 : png_bytep ep = sp + row_info->rowbytes; /* end+1 */
2615 :
2616 0 : while (sp < ep)
2617 : {
2618 : /* The input is an array of 16 bit components, these must be scaled to
2619 : * 8 bits each. For a 16 bit value V the required value (from the PNG
2620 : * specification) is:
2621 : *
2622 : * (V * 255) / 65535
2623 : *
2624 : * This reduces to round(V / 257), or floor((V + 128.5)/257)
2625 : *
2626 : * Represent V as the two byte value vhi.vlo. Make a guess that the
2627 : * result is the top byte of V, vhi, then the correction to this value
2628 : * is:
2629 : *
2630 : * error = floor(((V-vhi.vhi) + 128.5) / 257)
2631 : * = floor(((vlo-vhi) + 128.5) / 257)
2632 : *
2633 : * This can be approximated using integer arithmetic (and a signed
2634 : * shift):
2635 : *
2636 : * error = (vlo-vhi+128) >> 8;
2637 : *
2638 : * The approximate differs from the exact answer only when (vlo-vhi) is
2639 : * 128; it then gives a correction of +1 when the exact correction is
2640 : * 0. This gives 128 errors. The exact answer (correct for all 16 bit
2641 : * input values) is:
2642 : *
2643 : * error = (vlo-vhi+128)*65535 >> 24;
2644 : *
2645 : * An alternative arithmetic calculation which also gives no errors is:
2646 : *
2647 : * (V * 255 + 32895) >> 16
2648 : */
2649 :
2650 0 : png_int_32 tmp = *sp++; /* must be signed! */
2651 0 : tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24;
2652 0 : *dp++ = (png_byte)tmp;
2653 : }
2654 :
2655 0 : row_info->bit_depth = 8;
2656 0 : row_info->pixel_depth = (png_byte)(8 * row_info->channels);
2657 0 : row_info->rowbytes = row_info->width * row_info->channels;
2658 : }
2659 0 : }
2660 : #endif
2661 :
2662 : #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
2663 : void /* PRIVATE */
2664 : /* Simply discard the low byte. This was the default behavior prior
2665 : * to libpng-1.5.4.
2666 : */
2667 : png_do_chop(png_row_infop row_info, png_bytep row)
2668 : {
2669 : png_debug(1, "in png_do_chop");
2670 :
2671 : if (row_info->bit_depth == 16)
2672 : {
2673 : png_bytep sp = row; /* source */
2674 : png_bytep dp = row; /* destination */
2675 : png_bytep ep = sp + row_info->rowbytes; /* end+1 */
2676 :
2677 : while (sp < ep)
2678 : {
2679 : *dp++ = *sp;
2680 : sp += 2; /* skip low byte */
2681 : }
2682 :
2683 : row_info->bit_depth = 8;
2684 : row_info->pixel_depth = (png_byte)(8 * row_info->channels);
2685 : row_info->rowbytes = row_info->width * row_info->channels;
2686 : }
2687 : }
2688 : #endif
2689 :
2690 : #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
2691 : void /* PRIVATE */
2692 : png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
2693 : {
2694 : png_debug(1, "in png_do_read_swap_alpha");
2695 :
2696 : {
2697 : png_uint_32 row_width = row_info->width;
2698 : if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
2699 : {
2700 : /* This converts from RGBA to ARGB */
2701 : if (row_info->bit_depth == 8)
2702 : {
2703 : png_bytep sp = row + row_info->rowbytes;
2704 : png_bytep dp = sp;
2705 : png_byte save;
2706 : png_uint_32 i;
2707 :
2708 : for (i = 0; i < row_width; i++)
2709 : {
2710 : save = *(--sp);
2711 : *(--dp) = *(--sp);
2712 : *(--dp) = *(--sp);
2713 : *(--dp) = *(--sp);
2714 : *(--dp) = save;
2715 : }
2716 : }
2717 :
2718 : #ifdef PNG_READ_16BIT_SUPPORTED
2719 : /* This converts from RRGGBBAA to AARRGGBB */
2720 : else
2721 : {
2722 : png_bytep sp = row + row_info->rowbytes;
2723 : png_bytep dp = sp;
2724 : png_byte save[2];
2725 : png_uint_32 i;
2726 :
2727 : for (i = 0; i < row_width; i++)
2728 : {
2729 : save[0] = *(--sp);
2730 : save[1] = *(--sp);
2731 : *(--dp) = *(--sp);
2732 : *(--dp) = *(--sp);
2733 : *(--dp) = *(--sp);
2734 : *(--dp) = *(--sp);
2735 : *(--dp) = *(--sp);
2736 : *(--dp) = *(--sp);
2737 : *(--dp) = save[0];
2738 : *(--dp) = save[1];
2739 : }
2740 : }
2741 : #endif
2742 : }
2743 :
2744 : else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
2745 : {
2746 : /* This converts from GA to AG */
2747 : if (row_info->bit_depth == 8)
2748 : {
2749 : png_bytep sp = row + row_info->rowbytes;
2750 : png_bytep dp = sp;
2751 : png_byte save;
2752 : png_uint_32 i;
2753 :
2754 : for (i = 0; i < row_width; i++)
2755 : {
2756 : save = *(--sp);
2757 : *(--dp) = *(--sp);
2758 : *(--dp) = save;
2759 : }
2760 : }
2761 :
2762 : #ifdef PNG_READ_16BIT_SUPPORTED
2763 : /* This converts from GGAA to AAGG */
2764 : else
2765 : {
2766 : png_bytep sp = row + row_info->rowbytes;
2767 : png_bytep dp = sp;
2768 : png_byte save[2];
2769 : png_uint_32 i;
2770 :
2771 : for (i = 0; i < row_width; i++)
2772 : {
2773 : save[0] = *(--sp);
2774 : save[1] = *(--sp);
2775 : *(--dp) = *(--sp);
2776 : *(--dp) = *(--sp);
2777 : *(--dp) = save[0];
2778 : *(--dp) = save[1];
2779 : }
2780 : }
2781 : #endif
2782 : }
2783 : }
2784 : }
2785 : #endif
2786 :
2787 : #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
2788 : void /* PRIVATE */
2789 : png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
2790 : {
2791 : png_uint_32 row_width;
2792 : png_debug(1, "in png_do_read_invert_alpha");
2793 :
2794 : row_width = row_info->width;
2795 : if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
2796 : {
2797 : if (row_info->bit_depth == 8)
2798 : {
2799 : /* This inverts the alpha channel in RGBA */
2800 : png_bytep sp = row + row_info->rowbytes;
2801 : png_bytep dp = sp;
2802 : png_uint_32 i;
2803 :
2804 : for (i = 0; i < row_width; i++)
2805 : {
2806 : *(--dp) = (png_byte)(255 - *(--sp));
2807 :
2808 : /* This does nothing:
2809 : *(--dp) = *(--sp);
2810 : *(--dp) = *(--sp);
2811 : *(--dp) = *(--sp);
2812 : We can replace it with:
2813 : */
2814 : sp-=3;
2815 : dp=sp;
2816 : }
2817 : }
2818 :
2819 : #ifdef PNG_READ_16BIT_SUPPORTED
2820 : /* This inverts the alpha channel in RRGGBBAA */
2821 : else
2822 : {
2823 : png_bytep sp = row + row_info->rowbytes;
2824 : png_bytep dp = sp;
2825 : png_uint_32 i;
2826 :
2827 : for (i = 0; i < row_width; i++)
2828 : {
2829 : *(--dp) = (png_byte)(255 - *(--sp));
2830 : *(--dp) = (png_byte)(255 - *(--sp));
2831 :
2832 : /* This does nothing:
2833 : *(--dp) = *(--sp);
2834 : *(--dp) = *(--sp);
2835 : *(--dp) = *(--sp);
2836 : *(--dp) = *(--sp);
2837 : *(--dp) = *(--sp);
2838 : *(--dp) = *(--sp);
2839 : We can replace it with:
2840 : */
2841 : sp-=6;
2842 : dp=sp;
2843 : }
2844 : }
2845 : #endif
2846 : }
2847 : else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
2848 : {
2849 : if (row_info->bit_depth == 8)
2850 : {
2851 : /* This inverts the alpha channel in GA */
2852 : png_bytep sp = row + row_info->rowbytes;
2853 : png_bytep dp = sp;
2854 : png_uint_32 i;
2855 :
2856 : for (i = 0; i < row_width; i++)
2857 : {
2858 : *(--dp) = (png_byte)(255 - *(--sp));
2859 : *(--dp) = *(--sp);
2860 : }
2861 : }
2862 :
2863 : #ifdef PNG_READ_16BIT_SUPPORTED
2864 : else
2865 : {
2866 : /* This inverts the alpha channel in GGAA */
2867 : png_bytep sp = row + row_info->rowbytes;
2868 : png_bytep dp = sp;
2869 : png_uint_32 i;
2870 :
2871 : for (i = 0; i < row_width; i++)
2872 : {
2873 : *(--dp) = (png_byte)(255 - *(--sp));
2874 : *(--dp) = (png_byte)(255 - *(--sp));
2875 : /*
2876 : *(--dp) = *(--sp);
2877 : *(--dp) = *(--sp);
2878 : */
2879 : sp-=2;
2880 : dp=sp;
2881 : }
2882 : }
2883 : #endif
2884 : }
2885 : }
2886 : #endif
2887 :
2888 : #ifdef PNG_READ_FILLER_SUPPORTED
2889 : /* Add filler channel if we have RGB color */
2890 : void /* PRIVATE */
2891 : png_do_read_filler(png_row_infop row_info, png_bytep row,
2892 : png_uint_32 filler, png_uint_32 flags)
2893 : {
2894 : png_uint_32 i;
2895 : png_uint_32 row_width = row_info->width;
2896 :
2897 : #ifdef PNG_READ_16BIT_SUPPORTED
2898 : png_byte hi_filler = (png_byte)((filler>>8) & 0xff);
2899 : #endif
2900 : png_byte lo_filler = (png_byte)(filler & 0xff);
2901 :
2902 : png_debug(1, "in png_do_read_filler");
2903 :
2904 : if (
2905 : row_info->color_type == PNG_COLOR_TYPE_GRAY)
2906 : {
2907 : if (row_info->bit_depth == 8)
2908 : {
2909 : if (flags & PNG_FLAG_FILLER_AFTER)
2910 : {
2911 : /* This changes the data from G to GX */
2912 : png_bytep sp = row + (png_size_t)row_width;
2913 : png_bytep dp = sp + (png_size_t)row_width;
2914 : for (i = 1; i < row_width; i++)
2915 : {
2916 : *(--dp) = lo_filler;
2917 : *(--dp) = *(--sp);
2918 : }
2919 : *(--dp) = lo_filler;
2920 : row_info->channels = 2;
2921 : row_info->pixel_depth = 16;
2922 : row_info->rowbytes = row_width * 2;
2923 : }
2924 :
2925 : else
2926 : {
2927 : /* This changes the data from G to XG */
2928 : png_bytep sp = row + (png_size_t)row_width;
2929 : png_bytep dp = sp + (png_size_t)row_width;
2930 : for (i = 0; i < row_width; i++)
2931 : {
2932 : *(--dp) = *(--sp);
2933 : *(--dp) = lo_filler;
2934 : }
2935 : row_info->channels = 2;
2936 : row_info->pixel_depth = 16;
2937 : row_info->rowbytes = row_width * 2;
2938 : }
2939 : }
2940 :
2941 : #ifdef PNG_READ_16BIT_SUPPORTED
2942 : else if (row_info->bit_depth == 16)
2943 : {
2944 : if (flags & PNG_FLAG_FILLER_AFTER)
2945 : {
2946 : /* This changes the data from GG to GGXX */
2947 : png_bytep sp = row + (png_size_t)row_width * 2;
2948 : png_bytep dp = sp + (png_size_t)row_width * 2;
2949 : for (i = 1; i < row_width; i++)
2950 : {
2951 : *(--dp) = hi_filler;
2952 : *(--dp) = lo_filler;
2953 : *(--dp) = *(--sp);
2954 : *(--dp) = *(--sp);
2955 : }
2956 : *(--dp) = hi_filler;
2957 : *(--dp) = lo_filler;
2958 : row_info->channels = 2;
2959 : row_info->pixel_depth = 32;
2960 : row_info->rowbytes = row_width * 4;
2961 : }
2962 :
2963 : else
2964 : {
2965 : /* This changes the data from GG to XXGG */
2966 : png_bytep sp = row + (png_size_t)row_width * 2;
2967 : png_bytep dp = sp + (png_size_t)row_width * 2;
2968 : for (i = 0; i < row_width; i++)
2969 : {
2970 : *(--dp) = *(--sp);
2971 : *(--dp) = *(--sp);
2972 : *(--dp) = hi_filler;
2973 : *(--dp) = lo_filler;
2974 : }
2975 : row_info->channels = 2;
2976 : row_info->pixel_depth = 32;
2977 : row_info->rowbytes = row_width * 4;
2978 : }
2979 : }
2980 : #endif
2981 : } /* COLOR_TYPE == GRAY */
2982 : else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
2983 : {
2984 : if (row_info->bit_depth == 8)
2985 : {
2986 : if (flags & PNG_FLAG_FILLER_AFTER)
2987 : {
2988 : /* This changes the data from RGB to RGBX */
2989 : png_bytep sp = row + (png_size_t)row_width * 3;
2990 : png_bytep dp = sp + (png_size_t)row_width;
2991 : for (i = 1; i < row_width; i++)
2992 : {
2993 : *(--dp) = lo_filler;
2994 : *(--dp) = *(--sp);
2995 : *(--dp) = *(--sp);
2996 : *(--dp) = *(--sp);
2997 : }
2998 : *(--dp) = lo_filler;
2999 : row_info->channels = 4;
3000 : row_info->pixel_depth = 32;
3001 : row_info->rowbytes = row_width * 4;
3002 : }
3003 :
3004 : else
3005 : {
3006 : /* This changes the data from RGB to XRGB */
3007 : png_bytep sp = row + (png_size_t)row_width * 3;
3008 : png_bytep dp = sp + (png_size_t)row_width;
3009 : for (i = 0; i < row_width; i++)
3010 : {
3011 : *(--dp) = *(--sp);
3012 : *(--dp) = *(--sp);
3013 : *(--dp) = *(--sp);
3014 : *(--dp) = lo_filler;
3015 : }
3016 : row_info->channels = 4;
3017 : row_info->pixel_depth = 32;
3018 : row_info->rowbytes = row_width * 4;
3019 : }
3020 : }
3021 :
3022 : #ifdef PNG_READ_16BIT_SUPPORTED
3023 : else if (row_info->bit_depth == 16)
3024 : {
3025 : if (flags & PNG_FLAG_FILLER_AFTER)
3026 : {
3027 : /* This changes the data from RRGGBB to RRGGBBXX */
3028 : png_bytep sp = row + (png_size_t)row_width * 6;
3029 : png_bytep dp = sp + (png_size_t)row_width * 2;
3030 : for (i = 1; i < row_width; i++)
3031 : {
3032 : *(--dp) = hi_filler;
3033 : *(--dp) = lo_filler;
3034 : *(--dp) = *(--sp);
3035 : *(--dp) = *(--sp);
3036 : *(--dp) = *(--sp);
3037 : *(--dp) = *(--sp);
3038 : *(--dp) = *(--sp);
3039 : *(--dp) = *(--sp);
3040 : }
3041 : *(--dp) = hi_filler;
3042 : *(--dp) = lo_filler;
3043 : row_info->channels = 4;
3044 : row_info->pixel_depth = 64;
3045 : row_info->rowbytes = row_width * 8;
3046 : }
3047 :
3048 : else
3049 : {
3050 : /* This changes the data from RRGGBB to XXRRGGBB */
3051 : png_bytep sp = row + (png_size_t)row_width * 6;
3052 : png_bytep dp = sp + (png_size_t)row_width * 2;
3053 : for (i = 0; i < row_width; i++)
3054 : {
3055 : *(--dp) = *(--sp);
3056 : *(--dp) = *(--sp);
3057 : *(--dp) = *(--sp);
3058 : *(--dp) = *(--sp);
3059 : *(--dp) = *(--sp);
3060 : *(--dp) = *(--sp);
3061 : *(--dp) = hi_filler;
3062 : *(--dp) = lo_filler;
3063 : }
3064 :
3065 : row_info->channels = 4;
3066 : row_info->pixel_depth = 64;
3067 : row_info->rowbytes = row_width * 8;
3068 : }
3069 : }
3070 : #endif
3071 : } /* COLOR_TYPE == RGB */
3072 : }
3073 : #endif
3074 :
3075 : #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
3076 : /* Expand grayscale files to RGB, with or without alpha */
3077 : void /* PRIVATE */
3078 195 : png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
3079 : {
3080 : png_uint_32 i;
3081 195 : png_uint_32 row_width = row_info->width;
3082 :
3083 : png_debug(1, "in png_do_gray_to_rgb");
3084 :
3085 390 : if (row_info->bit_depth >= 8 &&
3086 195 : !(row_info->color_type & PNG_COLOR_MASK_COLOR))
3087 : {
3088 0 : if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
3089 : {
3090 0 : if (row_info->bit_depth == 8)
3091 : {
3092 : /* This changes G to RGB */
3093 0 : png_bytep sp = row + (png_size_t)row_width - 1;
3094 0 : png_bytep dp = sp + (png_size_t)row_width * 2;
3095 0 : for (i = 0; i < row_width; i++)
3096 : {
3097 0 : *(dp--) = *sp;
3098 0 : *(dp--) = *sp;
3099 0 : *(dp--) = *(sp--);
3100 : }
3101 : }
3102 :
3103 : else
3104 : {
3105 : /* This changes GG to RRGGBB */
3106 0 : png_bytep sp = row + (png_size_t)row_width * 2 - 1;
3107 0 : png_bytep dp = sp + (png_size_t)row_width * 4;
3108 0 : for (i = 0; i < row_width; i++)
3109 : {
3110 0 : *(dp--) = *sp;
3111 0 : *(dp--) = *(sp - 1);
3112 0 : *(dp--) = *sp;
3113 0 : *(dp--) = *(sp - 1);
3114 0 : *(dp--) = *(sp--);
3115 0 : *(dp--) = *(sp--);
3116 : }
3117 : }
3118 : }
3119 :
3120 0 : else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
3121 : {
3122 0 : if (row_info->bit_depth == 8)
3123 : {
3124 : /* This changes GA to RGBA */
3125 0 : png_bytep sp = row + (png_size_t)row_width * 2 - 1;
3126 0 : png_bytep dp = sp + (png_size_t)row_width * 2;
3127 0 : for (i = 0; i < row_width; i++)
3128 : {
3129 0 : *(dp--) = *(sp--);
3130 0 : *(dp--) = *sp;
3131 0 : *(dp--) = *sp;
3132 0 : *(dp--) = *(sp--);
3133 : }
3134 : }
3135 :
3136 : else
3137 : {
3138 : /* This changes GGAA to RRGGBBAA */
3139 0 : png_bytep sp = row + (png_size_t)row_width * 4 - 1;
3140 0 : png_bytep dp = sp + (png_size_t)row_width * 4;
3141 0 : for (i = 0; i < row_width; i++)
3142 : {
3143 0 : *(dp--) = *(sp--);
3144 0 : *(dp--) = *(sp--);
3145 0 : *(dp--) = *sp;
3146 0 : *(dp--) = *(sp - 1);
3147 0 : *(dp--) = *sp;
3148 0 : *(dp--) = *(sp - 1);
3149 0 : *(dp--) = *(sp--);
3150 0 : *(dp--) = *(sp--);
3151 : }
3152 : }
3153 : }
3154 0 : row_info->channels = (png_byte)(row_info->channels + 2);
3155 0 : row_info->color_type |= PNG_COLOR_MASK_COLOR;
3156 0 : row_info->pixel_depth = (png_byte)(row_info->channels *
3157 0 : row_info->bit_depth);
3158 0 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
3159 : }
3160 195 : }
3161 : #endif
3162 :
3163 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
3164 : /* Reduce RGB files to grayscale, with or without alpha
3165 : * using the equation given in Poynton's ColorFAQ of 1998-01-04 at
3166 : * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008 but
3167 : * versions dated 1998 through November 2002 have been archived at
3168 : * http://web.archive.org/web/20000816232553/http://www.inforamp.net/
3169 : * ~poynton/notes/colour_and_gamma/ColorFAQ.txt )
3170 : * Charles Poynton poynton at poynton.com
3171 : *
3172 : * Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
3173 : *
3174 : * which can be expressed with integers as
3175 : *
3176 : * Y = (6969 * R + 23434 * G + 2365 * B)/32768
3177 : *
3178 : * Poynton's current link (as of January 2003 through July 2011):
3179 : * <http://www.poynton.com/notes/colour_and_gamma/>
3180 : * has changed the numbers slightly:
3181 : *
3182 : * Y = 0.2126*R + 0.7152*G + 0.0722*B
3183 : *
3184 : * which can be expressed with integers as
3185 : *
3186 : * Y = (6966 * R + 23436 * G + 2366 * B)/32768
3187 : *
3188 : * Historically, however, libpng uses numbers derived from the ITU-R Rec 709
3189 : * end point chromaticities and the D65 white point. Depending on the
3190 : * precision used for the D65 white point this produces a variety of different
3191 : * numbers, however if the four decimal place value used in ITU-R Rec 709 is
3192 : * used (0.3127,0.3290) the Y calculation would be:
3193 : *
3194 : * Y = (6968 * R + 23435 * G + 2366 * B)/32768
3195 : *
3196 : * While this is correct the rounding results in an overflow for white, because
3197 : * the sum of the rounded coefficients is 32769, not 32768. Consequently
3198 : * libpng uses, instead, the closest non-overflowing approximation:
3199 : *
3200 : * Y = (6968 * R + 23434 * G + 2366 * B)/32768
3201 : *
3202 : * Starting with libpng-1.5.5, if the image being converted has a cHRM chunk
3203 : * (including an sRGB chunk) then the chromaticities are used to calculate the
3204 : * coefficients. See the chunk handling in pngrutil.c for more information.
3205 : *
3206 : * In all cases the calculation is to be done in a linear colorspace. If no
3207 : * gamma information is available to correct the encoding of the original RGB
3208 : * values this results in an implicit assumption that the original PNG RGB
3209 : * values were linear.
3210 : *
3211 : * Other integer coefficents can be used via png_set_rgb_to_gray(). Because
3212 : * the API takes just red and green coefficients the blue coefficient is
3213 : * calculated to make the sum 32768. This will result in different rounding
3214 : * to that used above.
3215 : */
3216 : int /* PRIVATE */
3217 : png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
3218 :
3219 : {
3220 : int rgb_error = 0;
3221 :
3222 : png_debug(1, "in png_do_rgb_to_gray");
3223 :
3224 : if (!(row_info->color_type & PNG_COLOR_MASK_PALETTE) &&
3225 : (row_info->color_type & PNG_COLOR_MASK_COLOR))
3226 : {
3227 : PNG_CONST png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
3228 : PNG_CONST png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
3229 : PNG_CONST png_uint_32 bc = 32768 - rc - gc;
3230 : PNG_CONST png_uint_32 row_width = row_info->width;
3231 : PNG_CONST int have_alpha =
3232 : (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0;
3233 :
3234 : if (row_info->bit_depth == 8)
3235 : {
3236 : #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
3237 : /* Notice that gamma to/from 1 are not necessarily inverses (if
3238 : * there is an overall gamma correction). Prior to 1.5.5 this code
3239 : * checked the linearized values for equality; this doesn't match
3240 : * the documentation, the original values must be checked.
3241 : */
3242 : if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
3243 : {
3244 : png_bytep sp = row;
3245 : png_bytep dp = row;
3246 : png_uint_32 i;
3247 :
3248 : for (i = 0; i < row_width; i++)
3249 : {
3250 : png_byte red = *(sp++);
3251 : png_byte green = *(sp++);
3252 : png_byte blue = *(sp++);
3253 :
3254 : if (red != green || red != blue)
3255 : {
3256 : red = png_ptr->gamma_to_1[red];
3257 : green = png_ptr->gamma_to_1[green];
3258 : blue = png_ptr->gamma_to_1[blue];
3259 :
3260 : rgb_error |= 1;
3261 : *(dp++) = png_ptr->gamma_from_1[
3262 : (rc*red + gc*green + bc*blue + 16384)>>15];
3263 : }
3264 :
3265 : else
3266 : {
3267 : /* If there is no overall correction the table will not be
3268 : * set.
3269 : */
3270 : if (png_ptr->gamma_table != NULL)
3271 : red = png_ptr->gamma_table[red];
3272 :
3273 : *(dp++) = red;
3274 : }
3275 :
3276 : if (have_alpha)
3277 : *(dp++) = *(sp++);
3278 : }
3279 : }
3280 : else
3281 : #endif
3282 : {
3283 : png_bytep sp = row;
3284 : png_bytep dp = row;
3285 : png_uint_32 i;
3286 :
3287 : for (i = 0; i < row_width; i++)
3288 : {
3289 : png_byte red = *(sp++);
3290 : png_byte green = *(sp++);
3291 : png_byte blue = *(sp++);
3292 :
3293 : if (red != green || red != blue)
3294 : {
3295 : rgb_error |= 1;
3296 : /*NOTE: this is the historical approach which simply
3297 : * truncates the results.
3298 : */
3299 : *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
3300 : }
3301 :
3302 : else
3303 : *(dp++) = red;
3304 :
3305 : if (have_alpha)
3306 : *(dp++) = *(sp++);
3307 : }
3308 : }
3309 : }
3310 :
3311 : else /* RGB bit_depth == 16 */
3312 : {
3313 : #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
3314 : if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL)
3315 : {
3316 : png_bytep sp = row;
3317 : png_bytep dp = row;
3318 : png_uint_32 i;
3319 :
3320 : for (i = 0; i < row_width; i++)
3321 : {
3322 : png_uint_16 red, green, blue, w;
3323 :
3324 : red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
3325 : green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
3326 : blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
3327 :
3328 : if (red == green && red == blue)
3329 : {
3330 : if (png_ptr->gamma_16_table != NULL)
3331 : w = png_ptr->gamma_16_table[(red&0xff)
3332 : >> png_ptr->gamma_shift][red>>8];
3333 :
3334 : else
3335 : w = red;
3336 : }
3337 :
3338 : else
3339 : {
3340 : png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff)
3341 : >> png_ptr->gamma_shift][red>>8];
3342 : png_uint_16 green_1 =
3343 : png_ptr->gamma_16_to_1[(green&0xff) >>
3344 : png_ptr->gamma_shift][green>>8];
3345 : png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff)
3346 : >> png_ptr->gamma_shift][blue>>8];
3347 : png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1
3348 : + bc*blue_1 + 16384)>>15);
3349 : w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
3350 : png_ptr->gamma_shift][gray16 >> 8];
3351 : rgb_error |= 1;
3352 : }
3353 :
3354 : *(dp++) = (png_byte)((w>>8) & 0xff);
3355 : *(dp++) = (png_byte)(w & 0xff);
3356 :
3357 : if (have_alpha)
3358 : {
3359 : *(dp++) = *(sp++);
3360 : *(dp++) = *(sp++);
3361 : }
3362 : }
3363 : }
3364 : else
3365 : #endif
3366 : {
3367 : png_bytep sp = row;
3368 : png_bytep dp = row;
3369 : png_uint_32 i;
3370 :
3371 : for (i = 0; i < row_width; i++)
3372 : {
3373 : png_uint_16 red, green, blue, gray16;
3374 :
3375 : red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
3376 : green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
3377 : blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2;
3378 :
3379 : if (red != green || red != blue)
3380 : rgb_error |= 1;
3381 :
3382 : /* From 1.5.5 in the 16 bit case do the accurate conversion even
3383 : * in the 'fast' case - this is because this is where the code
3384 : * ends up when handling linear 16 bit data.
3385 : */
3386 : gray16 = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
3387 : 15);
3388 : *(dp++) = (png_byte)((gray16>>8) & 0xff);
3389 : *(dp++) = (png_byte)(gray16 & 0xff);
3390 :
3391 : if (have_alpha)
3392 : {
3393 : *(dp++) = *(sp++);
3394 : *(dp++) = *(sp++);
3395 : }
3396 : }
3397 : }
3398 : }
3399 :
3400 : row_info->channels = (png_byte)(row_info->channels - 2);
3401 : row_info->color_type = (png_byte)(row_info->color_type &
3402 : ~PNG_COLOR_MASK_COLOR);
3403 : row_info->pixel_depth = (png_byte)(row_info->channels *
3404 : row_info->bit_depth);
3405 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
3406 : }
3407 : return rgb_error;
3408 : }
3409 : #endif
3410 : #endif /* PNG_READ_TRANSFORMS_SUPPORTED */
3411 :
3412 : #ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
3413 : /* Build a grayscale palette. Palette is assumed to be 1 << bit_depth
3414 : * large of png_color. This lets grayscale images be treated as
3415 : * paletted. Most useful for gamma correction and simplification
3416 : * of code. This API is not used internally.
3417 : */
3418 : void PNGAPI
3419 : png_build_grayscale_palette(int bit_depth, png_colorp palette)
3420 : {
3421 : int num_palette;
3422 : int color_inc;
3423 : int i;
3424 : int v;
3425 :
3426 : png_debug(1, "in png_do_build_grayscale_palette");
3427 :
3428 : if (palette == NULL)
3429 : return;
3430 :
3431 : switch (bit_depth)
3432 : {
3433 : case 1:
3434 : num_palette = 2;
3435 : color_inc = 0xff;
3436 : break;
3437 :
3438 : case 2:
3439 : num_palette = 4;
3440 : color_inc = 0x55;
3441 : break;
3442 :
3443 : case 4:
3444 : num_palette = 16;
3445 : color_inc = 0x11;
3446 : break;
3447 :
3448 : case 8:
3449 : num_palette = 256;
3450 : color_inc = 1;
3451 : break;
3452 :
3453 : default:
3454 : num_palette = 0;
3455 : color_inc = 0;
3456 : break;
3457 : }
3458 :
3459 : for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
3460 : {
3461 : palette[i].red = (png_byte)v;
3462 : palette[i].green = (png_byte)v;
3463 : palette[i].blue = (png_byte)v;
3464 : }
3465 : }
3466 : #endif
3467 :
3468 :
3469 : #ifdef PNG_READ_TRANSFORMS_SUPPORTED
3470 : #if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
3471 : (defined PNG_READ_ALPHA_MODE_SUPPORTED)
3472 : /* Replace any alpha or transparency with the supplied background color.
3473 : * "background" is already in the screen gamma, while "background_1" is
3474 : * at a gamma of 1.0. Paletted files have already been taken care of.
3475 : */
3476 : void /* PRIVATE */
3477 : png_do_compose(png_row_infop row_info, png_bytep row, png_structp png_ptr)
3478 : {
3479 : #ifdef PNG_READ_GAMMA_SUPPORTED
3480 : png_const_bytep gamma_table = png_ptr->gamma_table;
3481 : png_const_bytep gamma_from_1 = png_ptr->gamma_from_1;
3482 : png_const_bytep gamma_to_1 = png_ptr->gamma_to_1;
3483 : png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table;
3484 : png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1;
3485 : png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1;
3486 : int gamma_shift = png_ptr->gamma_shift;
3487 : #endif
3488 :
3489 : png_bytep sp;
3490 : png_uint_32 i;
3491 : png_uint_32 row_width = row_info->width;
3492 : int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0;
3493 : int shift;
3494 :
3495 : png_debug(1, "in png_do_compose");
3496 :
3497 : {
3498 : switch (row_info->color_type)
3499 : {
3500 : case PNG_COLOR_TYPE_GRAY:
3501 : {
3502 : switch (row_info->bit_depth)
3503 : {
3504 : case 1:
3505 : {
3506 : sp = row;
3507 : shift = 7;
3508 : for (i = 0; i < row_width; i++)
3509 : {
3510 : if ((png_uint_16)((*sp >> shift) & 0x01)
3511 : == png_ptr->trans_color.gray)
3512 : {
3513 : *sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
3514 : *sp |= (png_byte)(png_ptr->background.gray << shift);
3515 : }
3516 :
3517 : if (!shift)
3518 : {
3519 : shift = 7;
3520 : sp++;
3521 : }
3522 :
3523 : else
3524 : shift--;
3525 : }
3526 : break;
3527 : }
3528 :
3529 : case 2:
3530 : {
3531 : #ifdef PNG_READ_GAMMA_SUPPORTED
3532 : if (gamma_table != NULL)
3533 : {
3534 : sp = row;
3535 : shift = 6;
3536 : for (i = 0; i < row_width; i++)
3537 : {
3538 : if ((png_uint_16)((*sp >> shift) & 0x03)
3539 : == png_ptr->trans_color.gray)
3540 : {
3541 : *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
3542 : *sp |= (png_byte)(png_ptr->background.gray << shift);
3543 : }
3544 :
3545 : else
3546 : {
3547 : png_byte p = (png_byte)((*sp >> shift) & 0x03);
3548 : png_byte g = (png_byte)((gamma_table [p | (p << 2) |
3549 : (p << 4) | (p << 6)] >> 6) & 0x03);
3550 : *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
3551 : *sp |= (png_byte)(g << shift);
3552 : }
3553 :
3554 : if (!shift)
3555 : {
3556 : shift = 6;
3557 : sp++;
3558 : }
3559 :
3560 : else
3561 : shift -= 2;
3562 : }
3563 : }
3564 :
3565 : else
3566 : #endif
3567 : {
3568 : sp = row;
3569 : shift = 6;
3570 : for (i = 0; i < row_width; i++)
3571 : {
3572 : if ((png_uint_16)((*sp >> shift) & 0x03)
3573 : == png_ptr->trans_color.gray)
3574 : {
3575 : *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
3576 : *sp |= (png_byte)(png_ptr->background.gray << shift);
3577 : }
3578 :
3579 : if (!shift)
3580 : {
3581 : shift = 6;
3582 : sp++;
3583 : }
3584 :
3585 : else
3586 : shift -= 2;
3587 : }
3588 : }
3589 : break;
3590 : }
3591 :
3592 : case 4:
3593 : {
3594 : #ifdef PNG_READ_GAMMA_SUPPORTED
3595 : if (gamma_table != NULL)
3596 : {
3597 : sp = row;
3598 : shift = 4;
3599 : for (i = 0; i < row_width; i++)
3600 : {
3601 : if ((png_uint_16)((*sp >> shift) & 0x0f)
3602 : == png_ptr->trans_color.gray)
3603 : {
3604 : *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
3605 : *sp |= (png_byte)(png_ptr->background.gray << shift);
3606 : }
3607 :
3608 : else
3609 : {
3610 : png_byte p = (png_byte)((*sp >> shift) & 0x0f);
3611 : png_byte g = (png_byte)((gamma_table[p |
3612 : (p << 4)] >> 4) & 0x0f);
3613 : *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
3614 : *sp |= (png_byte)(g << shift);
3615 : }
3616 :
3617 : if (!shift)
3618 : {
3619 : shift = 4;
3620 : sp++;
3621 : }
3622 :
3623 : else
3624 : shift -= 4;
3625 : }
3626 : }
3627 :
3628 : else
3629 : #endif
3630 : {
3631 : sp = row;
3632 : shift = 4;
3633 : for (i = 0; i < row_width; i++)
3634 : {
3635 : if ((png_uint_16)((*sp >> shift) & 0x0f)
3636 : == png_ptr->trans_color.gray)
3637 : {
3638 : *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
3639 : *sp |= (png_byte)(png_ptr->background.gray << shift);
3640 : }
3641 :
3642 : if (!shift)
3643 : {
3644 : shift = 4;
3645 : sp++;
3646 : }
3647 :
3648 : else
3649 : shift -= 4;
3650 : }
3651 : }
3652 : break;
3653 : }
3654 :
3655 : case 8:
3656 : {
3657 : #ifdef PNG_READ_GAMMA_SUPPORTED
3658 : if (gamma_table != NULL)
3659 : {
3660 : sp = row;
3661 : for (i = 0; i < row_width; i++, sp++)
3662 : {
3663 : if (*sp == png_ptr->trans_color.gray)
3664 : *sp = (png_byte)png_ptr->background.gray;
3665 :
3666 : else
3667 : *sp = gamma_table[*sp];
3668 : }
3669 : }
3670 : else
3671 : #endif
3672 : {
3673 : sp = row;
3674 : for (i = 0; i < row_width; i++, sp++)
3675 : {
3676 : if (*sp == png_ptr->trans_color.gray)
3677 : *sp = (png_byte)png_ptr->background.gray;
3678 : }
3679 : }
3680 : break;
3681 : }
3682 :
3683 : case 16:
3684 : {
3685 : #ifdef PNG_READ_GAMMA_SUPPORTED
3686 : if (gamma_16 != NULL)
3687 : {
3688 : sp = row;
3689 : for (i = 0; i < row_width; i++, sp += 2)
3690 : {
3691 : png_uint_16 v;
3692 :
3693 : v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3694 :
3695 : if (v == png_ptr->trans_color.gray)
3696 : {
3697 : /* Background is already in screen gamma */
3698 : *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff);
3699 : *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
3700 : }
3701 :
3702 : else
3703 : {
3704 : v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
3705 : *sp = (png_byte)((v >> 8) & 0xff);
3706 : *(sp + 1) = (png_byte)(v & 0xff);
3707 : }
3708 : }
3709 : }
3710 : else
3711 : #endif
3712 : {
3713 : sp = row;
3714 : for (i = 0; i < row_width; i++, sp += 2)
3715 : {
3716 : png_uint_16 v;
3717 :
3718 : v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3719 :
3720 : if (v == png_ptr->trans_color.gray)
3721 : {
3722 : *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff);
3723 : *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
3724 : }
3725 : }
3726 : }
3727 : break;
3728 : }
3729 :
3730 : default:
3731 : break;
3732 : }
3733 : break;
3734 : }
3735 :
3736 : case PNG_COLOR_TYPE_RGB:
3737 : {
3738 : if (row_info->bit_depth == 8)
3739 : {
3740 : #ifdef PNG_READ_GAMMA_SUPPORTED
3741 : if (gamma_table != NULL)
3742 : {
3743 : sp = row;
3744 : for (i = 0; i < row_width; i++, sp += 3)
3745 : {
3746 : if (*sp == png_ptr->trans_color.red &&
3747 : *(sp + 1) == png_ptr->trans_color.green &&
3748 : *(sp + 2) == png_ptr->trans_color.blue)
3749 : {
3750 : *sp = (png_byte)png_ptr->background.red;
3751 : *(sp + 1) = (png_byte)png_ptr->background.green;
3752 : *(sp + 2) = (png_byte)png_ptr->background.blue;
3753 : }
3754 :
3755 : else
3756 : {
3757 : *sp = gamma_table[*sp];
3758 : *(sp + 1) = gamma_table[*(sp + 1)];
3759 : *(sp + 2) = gamma_table[*(sp + 2)];
3760 : }
3761 : }
3762 : }
3763 : else
3764 : #endif
3765 : {
3766 : sp = row;
3767 : for (i = 0; i < row_width; i++, sp += 3)
3768 : {
3769 : if (*sp == png_ptr->trans_color.red &&
3770 : *(sp + 1) == png_ptr->trans_color.green &&
3771 : *(sp + 2) == png_ptr->trans_color.blue)
3772 : {
3773 : *sp = (png_byte)png_ptr->background.red;
3774 : *(sp + 1) = (png_byte)png_ptr->background.green;
3775 : *(sp + 2) = (png_byte)png_ptr->background.blue;
3776 : }
3777 : }
3778 : }
3779 : }
3780 : else /* if (row_info->bit_depth == 16) */
3781 : {
3782 : #ifdef PNG_READ_GAMMA_SUPPORTED
3783 : if (gamma_16 != NULL)
3784 : {
3785 : sp = row;
3786 : for (i = 0; i < row_width; i++, sp += 6)
3787 : {
3788 : png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3789 :
3790 : png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
3791 : + *(sp + 3));
3792 :
3793 : png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
3794 : + *(sp + 5));
3795 :
3796 : if (r == png_ptr->trans_color.red &&
3797 : g == png_ptr->trans_color.green &&
3798 : b == png_ptr->trans_color.blue)
3799 : {
3800 : /* Background is already in screen gamma */
3801 : *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
3802 : *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
3803 : *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff);
3804 : *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff);
3805 : *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff);
3806 : *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
3807 : }
3808 :
3809 : else
3810 : {
3811 : png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
3812 : *sp = (png_byte)((v >> 8) & 0xff);
3813 : *(sp + 1) = (png_byte)(v & 0xff);
3814 :
3815 : v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
3816 : *(sp + 2) = (png_byte)((v >> 8) & 0xff);
3817 : *(sp + 3) = (png_byte)(v & 0xff);
3818 :
3819 : v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
3820 : *(sp + 4) = (png_byte)((v >> 8) & 0xff);
3821 : *(sp + 5) = (png_byte)(v & 0xff);
3822 : }
3823 : }
3824 : }
3825 :
3826 : else
3827 : #endif
3828 : {
3829 : sp = row;
3830 : for (i = 0; i < row_width; i++, sp += 6)
3831 : {
3832 : png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3833 :
3834 : png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
3835 : + *(sp + 3));
3836 :
3837 : png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
3838 : + *(sp + 5));
3839 :
3840 : if (r == png_ptr->trans_color.red &&
3841 : g == png_ptr->trans_color.green &&
3842 : b == png_ptr->trans_color.blue)
3843 : {
3844 : *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
3845 : *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
3846 : *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff);
3847 : *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff);
3848 : *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff);
3849 : *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
3850 : }
3851 : }
3852 : }
3853 : }
3854 : break;
3855 : }
3856 :
3857 : case PNG_COLOR_TYPE_GRAY_ALPHA:
3858 : {
3859 : if (row_info->bit_depth == 8)
3860 : {
3861 : #ifdef PNG_READ_GAMMA_SUPPORTED
3862 : if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
3863 : gamma_table != NULL)
3864 : {
3865 : sp = row;
3866 : for (i = 0; i < row_width; i++, sp += 2)
3867 : {
3868 : png_uint_16 a = *(sp + 1);
3869 :
3870 : if (a == 0xff)
3871 : *sp = gamma_table[*sp];
3872 :
3873 : else if (a == 0)
3874 : {
3875 : /* Background is already in screen gamma */
3876 : *sp = (png_byte)png_ptr->background.gray;
3877 : }
3878 :
3879 : else
3880 : {
3881 : png_byte v, w;
3882 :
3883 : v = gamma_to_1[*sp];
3884 : png_composite(w, v, a, png_ptr->background_1.gray);
3885 : if (!optimize)
3886 : w = gamma_from_1[w];
3887 : *sp = w;
3888 : }
3889 : }
3890 : }
3891 : else
3892 : #endif
3893 : {
3894 : sp = row;
3895 : for (i = 0; i < row_width; i++, sp += 2)
3896 : {
3897 : png_byte a = *(sp + 1);
3898 :
3899 : if (a == 0)
3900 : *sp = (png_byte)png_ptr->background.gray;
3901 :
3902 : else if (a < 0xff)
3903 : png_composite(*sp, *sp, a, png_ptr->background_1.gray);
3904 : }
3905 : }
3906 : }
3907 : else /* if (png_ptr->bit_depth == 16) */
3908 : {
3909 : #ifdef PNG_READ_GAMMA_SUPPORTED
3910 : if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
3911 : gamma_16_to_1 != NULL)
3912 : {
3913 : sp = row;
3914 : for (i = 0; i < row_width; i++, sp += 4)
3915 : {
3916 : png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
3917 : + *(sp + 3));
3918 :
3919 : if (a == (png_uint_16)0xffff)
3920 : {
3921 : png_uint_16 v;
3922 :
3923 : v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
3924 : *sp = (png_byte)((v >> 8) & 0xff);
3925 : *(sp + 1) = (png_byte)(v & 0xff);
3926 : }
3927 :
3928 : else if (a == 0)
3929 : {
3930 : /* Background is already in screen gamma */
3931 : *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff);
3932 : *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
3933 : }
3934 :
3935 : else
3936 : {
3937 : png_uint_16 g, v, w;
3938 :
3939 : g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
3940 : png_composite_16(v, g, a, png_ptr->background_1.gray);
3941 : if (optimize)
3942 : w = v;
3943 : else
3944 : w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
3945 : *sp = (png_byte)((w >> 8) & 0xff);
3946 : *(sp + 1) = (png_byte)(w & 0xff);
3947 : }
3948 : }
3949 : }
3950 : else
3951 : #endif
3952 : {
3953 : sp = row;
3954 : for (i = 0; i < row_width; i++, sp += 4)
3955 : {
3956 : png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
3957 : + *(sp + 3));
3958 :
3959 : if (a == 0)
3960 : {
3961 : *sp = (png_byte)((png_ptr->background.gray >> 8) & 0xff);
3962 : *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
3963 : }
3964 :
3965 : else if (a < 0xffff)
3966 : {
3967 : png_uint_16 g, v;
3968 :
3969 : g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3970 : png_composite_16(v, g, a, png_ptr->background_1.gray);
3971 : *sp = (png_byte)((v >> 8) & 0xff);
3972 : *(sp + 1) = (png_byte)(v & 0xff);
3973 : }
3974 : }
3975 : }
3976 : }
3977 : break;
3978 : }
3979 :
3980 : case PNG_COLOR_TYPE_RGB_ALPHA:
3981 : {
3982 : if (row_info->bit_depth == 8)
3983 : {
3984 : #ifdef PNG_READ_GAMMA_SUPPORTED
3985 : if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
3986 : gamma_table != NULL)
3987 : {
3988 : sp = row;
3989 : for (i = 0; i < row_width; i++, sp += 4)
3990 : {
3991 : png_byte a = *(sp + 3);
3992 :
3993 : if (a == 0xff)
3994 : {
3995 : *sp = gamma_table[*sp];
3996 : *(sp + 1) = gamma_table[*(sp + 1)];
3997 : *(sp + 2) = gamma_table[*(sp + 2)];
3998 : }
3999 :
4000 : else if (a == 0)
4001 : {
4002 : /* Background is already in screen gamma */
4003 : *sp = (png_byte)png_ptr->background.red;
4004 : *(sp + 1) = (png_byte)png_ptr->background.green;
4005 : *(sp + 2) = (png_byte)png_ptr->background.blue;
4006 : }
4007 :
4008 : else
4009 : {
4010 : png_byte v, w;
4011 :
4012 : v = gamma_to_1[*sp];
4013 : png_composite(w, v, a, png_ptr->background_1.red);
4014 : if (!optimize) w = gamma_from_1[w];
4015 : *sp = w;
4016 :
4017 : v = gamma_to_1[*(sp + 1)];
4018 : png_composite(w, v, a, png_ptr->background_1.green);
4019 : if (!optimize) w = gamma_from_1[w];
4020 : *(sp + 1) = w;
4021 :
4022 : v = gamma_to_1[*(sp + 2)];
4023 : png_composite(w, v, a, png_ptr->background_1.blue);
4024 : if (!optimize) w = gamma_from_1[w];
4025 : *(sp + 2) = w;
4026 : }
4027 : }
4028 : }
4029 : else
4030 : #endif
4031 : {
4032 : sp = row;
4033 : for (i = 0; i < row_width; i++, sp += 4)
4034 : {
4035 : png_byte a = *(sp + 3);
4036 :
4037 : if (a == 0)
4038 : {
4039 : *sp = (png_byte)png_ptr->background.red;
4040 : *(sp + 1) = (png_byte)png_ptr->background.green;
4041 : *(sp + 2) = (png_byte)png_ptr->background.blue;
4042 : }
4043 :
4044 : else if (a < 0xff)
4045 : {
4046 : png_composite(*sp, *sp, a, png_ptr->background.red);
4047 :
4048 : png_composite(*(sp + 1), *(sp + 1), a,
4049 : png_ptr->background.green);
4050 :
4051 : png_composite(*(sp + 2), *(sp + 2), a,
4052 : png_ptr->background.blue);
4053 : }
4054 : }
4055 : }
4056 : }
4057 : else /* if (row_info->bit_depth == 16) */
4058 : {
4059 : #ifdef PNG_READ_GAMMA_SUPPORTED
4060 : if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
4061 : gamma_16_to_1 != NULL)
4062 : {
4063 : sp = row;
4064 : for (i = 0; i < row_width; i++, sp += 8)
4065 : {
4066 : png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
4067 : << 8) + (png_uint_16)(*(sp + 7)));
4068 :
4069 : if (a == (png_uint_16)0xffff)
4070 : {
4071 : png_uint_16 v;
4072 :
4073 : v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
4074 : *sp = (png_byte)((v >> 8) & 0xff);
4075 : *(sp + 1) = (png_byte)(v & 0xff);
4076 :
4077 : v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
4078 : *(sp + 2) = (png_byte)((v >> 8) & 0xff);
4079 : *(sp + 3) = (png_byte)(v & 0xff);
4080 :
4081 : v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
4082 : *(sp + 4) = (png_byte)((v >> 8) & 0xff);
4083 : *(sp + 5) = (png_byte)(v & 0xff);
4084 : }
4085 :
4086 : else if (a == 0)
4087 : {
4088 : /* Background is already in screen gamma */
4089 : *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
4090 : *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
4091 : *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff);
4092 : *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff);
4093 : *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff);
4094 : *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
4095 : }
4096 :
4097 : else
4098 : {
4099 : png_uint_16 v, w;
4100 :
4101 : v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
4102 : png_composite_16(w, v, a, png_ptr->background_1.red);
4103 : if (!optimize)
4104 : w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
4105 : *sp = (png_byte)((w >> 8) & 0xff);
4106 : *(sp + 1) = (png_byte)(w & 0xff);
4107 :
4108 : v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
4109 : png_composite_16(w, v, a, png_ptr->background_1.green);
4110 : if (!optimize)
4111 : w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
4112 :
4113 : *(sp + 2) = (png_byte)((w >> 8) & 0xff);
4114 : *(sp + 3) = (png_byte)(w & 0xff);
4115 :
4116 : v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
4117 : png_composite_16(w, v, a, png_ptr->background_1.blue);
4118 : if (!optimize)
4119 : w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
4120 :
4121 : *(sp + 4) = (png_byte)((w >> 8) & 0xff);
4122 : *(sp + 5) = (png_byte)(w & 0xff);
4123 : }
4124 : }
4125 : }
4126 :
4127 : else
4128 : #endif
4129 : {
4130 : sp = row;
4131 : for (i = 0; i < row_width; i++, sp += 8)
4132 : {
4133 : png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
4134 : << 8) + (png_uint_16)(*(sp + 7)));
4135 :
4136 : if (a == 0)
4137 : {
4138 : *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
4139 : *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
4140 : *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) & 0xff);
4141 : *(sp + 3) = (png_byte)(png_ptr->background.green & 0xff);
4142 : *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) & 0xff);
4143 : *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
4144 : }
4145 :
4146 : else if (a < 0xffff)
4147 : {
4148 : png_uint_16 v;
4149 :
4150 : png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
4151 : png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
4152 : + *(sp + 3));
4153 : png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
4154 : + *(sp + 5));
4155 :
4156 : png_composite_16(v, r, a, png_ptr->background.red);
4157 : *sp = (png_byte)((v >> 8) & 0xff);
4158 : *(sp + 1) = (png_byte)(v & 0xff);
4159 :
4160 : png_composite_16(v, g, a, png_ptr->background.green);
4161 : *(sp + 2) = (png_byte)((v >> 8) & 0xff);
4162 : *(sp + 3) = (png_byte)(v & 0xff);
4163 :
4164 : png_composite_16(v, b, a, png_ptr->background.blue);
4165 : *(sp + 4) = (png_byte)((v >> 8) & 0xff);
4166 : *(sp + 5) = (png_byte)(v & 0xff);
4167 : }
4168 : }
4169 : }
4170 : }
4171 : break;
4172 : }
4173 :
4174 : default:
4175 : break;
4176 : }
4177 : }
4178 : }
4179 : #endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_READ_ALPHA_MODE_SUPPORTED */
4180 :
4181 : #ifdef PNG_READ_GAMMA_SUPPORTED
4182 : /* Gamma correct the image, avoiding the alpha channel. Make sure
4183 : * you do this after you deal with the transparency issue on grayscale
4184 : * or RGB images. If your bit depth is 8, use gamma_table, if it
4185 : * is 16, use gamma_16_table and gamma_shift. Build these with
4186 : * build_gamma_table().
4187 : */
4188 : void /* PRIVATE */
4189 0 : png_do_gamma(png_row_infop row_info, png_bytep row, png_structp png_ptr)
4190 : {
4191 0 : png_const_bytep gamma_table = png_ptr->gamma_table;
4192 0 : png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table;
4193 0 : int gamma_shift = png_ptr->gamma_shift;
4194 :
4195 : png_bytep sp;
4196 : png_uint_32 i;
4197 0 : png_uint_32 row_width=row_info->width;
4198 :
4199 : png_debug(1, "in png_do_gamma");
4200 :
4201 0 : if (((row_info->bit_depth <= 8 && gamma_table != NULL) ||
4202 0 : (row_info->bit_depth == 16 && gamma_16_table != NULL)))
4203 : {
4204 0 : switch (row_info->color_type)
4205 : {
4206 : case PNG_COLOR_TYPE_RGB:
4207 : {
4208 0 : if (row_info->bit_depth == 8)
4209 : {
4210 0 : sp = row;
4211 0 : for (i = 0; i < row_width; i++)
4212 : {
4213 0 : *sp = gamma_table[*sp];
4214 0 : sp++;
4215 0 : *sp = gamma_table[*sp];
4216 0 : sp++;
4217 0 : *sp = gamma_table[*sp];
4218 0 : sp++;
4219 : }
4220 : }
4221 :
4222 : else /* if (row_info->bit_depth == 16) */
4223 : {
4224 0 : sp = row;
4225 0 : for (i = 0; i < row_width; i++)
4226 : {
4227 : png_uint_16 v;
4228 :
4229 0 : v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4230 0 : *sp = (png_byte)((v >> 8) & 0xff);
4231 0 : *(sp + 1) = (png_byte)(v & 0xff);
4232 0 : sp += 2;
4233 :
4234 0 : v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4235 0 : *sp = (png_byte)((v >> 8) & 0xff);
4236 0 : *(sp + 1) = (png_byte)(v & 0xff);
4237 0 : sp += 2;
4238 :
4239 0 : v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4240 0 : *sp = (png_byte)((v >> 8) & 0xff);
4241 0 : *(sp + 1) = (png_byte)(v & 0xff);
4242 0 : sp += 2;
4243 : }
4244 : }
4245 0 : break;
4246 : }
4247 :
4248 : case PNG_COLOR_TYPE_RGB_ALPHA:
4249 : {
4250 0 : if (row_info->bit_depth == 8)
4251 : {
4252 0 : sp = row;
4253 0 : for (i = 0; i < row_width; i++)
4254 : {
4255 0 : *sp = gamma_table[*sp];
4256 0 : sp++;
4257 :
4258 0 : *sp = gamma_table[*sp];
4259 0 : sp++;
4260 :
4261 0 : *sp = gamma_table[*sp];
4262 0 : sp++;
4263 :
4264 0 : sp++;
4265 : }
4266 : }
4267 :
4268 : else /* if (row_info->bit_depth == 16) */
4269 : {
4270 0 : sp = row;
4271 0 : for (i = 0; i < row_width; i++)
4272 : {
4273 0 : png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4274 0 : *sp = (png_byte)((v >> 8) & 0xff);
4275 0 : *(sp + 1) = (png_byte)(v & 0xff);
4276 0 : sp += 2;
4277 :
4278 0 : v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4279 0 : *sp = (png_byte)((v >> 8) & 0xff);
4280 0 : *(sp + 1) = (png_byte)(v & 0xff);
4281 0 : sp += 2;
4282 :
4283 0 : v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4284 0 : *sp = (png_byte)((v >> 8) & 0xff);
4285 0 : *(sp + 1) = (png_byte)(v & 0xff);
4286 0 : sp += 4;
4287 : }
4288 : }
4289 0 : break;
4290 : }
4291 :
4292 : case PNG_COLOR_TYPE_GRAY_ALPHA:
4293 : {
4294 0 : if (row_info->bit_depth == 8)
4295 : {
4296 0 : sp = row;
4297 0 : for (i = 0; i < row_width; i++)
4298 : {
4299 0 : *sp = gamma_table[*sp];
4300 0 : sp += 2;
4301 : }
4302 : }
4303 :
4304 : else /* if (row_info->bit_depth == 16) */
4305 : {
4306 0 : sp = row;
4307 0 : for (i = 0; i < row_width; i++)
4308 : {
4309 0 : png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4310 0 : *sp = (png_byte)((v >> 8) & 0xff);
4311 0 : *(sp + 1) = (png_byte)(v & 0xff);
4312 0 : sp += 4;
4313 : }
4314 : }
4315 0 : break;
4316 : }
4317 :
4318 : case PNG_COLOR_TYPE_GRAY:
4319 : {
4320 0 : if (row_info->bit_depth == 2)
4321 : {
4322 0 : sp = row;
4323 0 : for (i = 0; i < row_width; i += 4)
4324 : {
4325 0 : int a = *sp & 0xc0;
4326 0 : int b = *sp & 0x30;
4327 0 : int c = *sp & 0x0c;
4328 0 : int d = *sp & 0x03;
4329 :
4330 0 : *sp = (png_byte)(
4331 0 : ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)]) ) & 0xc0)|
4332 0 : ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
4333 0 : ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
4334 0 : ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
4335 0 : sp++;
4336 : }
4337 : }
4338 :
4339 0 : if (row_info->bit_depth == 4)
4340 : {
4341 0 : sp = row;
4342 0 : for (i = 0; i < row_width; i += 2)
4343 : {
4344 0 : int msb = *sp & 0xf0;
4345 0 : int lsb = *sp & 0x0f;
4346 :
4347 0 : *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
4348 0 : | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
4349 0 : sp++;
4350 : }
4351 : }
4352 :
4353 0 : else if (row_info->bit_depth == 8)
4354 : {
4355 0 : sp = row;
4356 0 : for (i = 0; i < row_width; i++)
4357 : {
4358 0 : *sp = gamma_table[*sp];
4359 0 : sp++;
4360 : }
4361 : }
4362 :
4363 0 : else if (row_info->bit_depth == 16)
4364 : {
4365 0 : sp = row;
4366 0 : for (i = 0; i < row_width; i++)
4367 : {
4368 0 : png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4369 0 : *sp = (png_byte)((v >> 8) & 0xff);
4370 0 : *(sp + 1) = (png_byte)(v & 0xff);
4371 0 : sp += 2;
4372 : }
4373 : }
4374 0 : break;
4375 : }
4376 :
4377 : default:
4378 0 : break;
4379 : }
4380 : }
4381 0 : }
4382 : #endif
4383 :
4384 : #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
4385 : /* Encode the alpha channel to the output gamma (the input channel is always
4386 : * linear.) Called only with color types that have an alpha channel. Needs the
4387 : * from_1 tables.
4388 : */
4389 : void /* PRIVATE */
4390 : png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structp png_ptr)
4391 : {
4392 : png_uint_32 row_width = row_info->width;
4393 :
4394 : png_debug(1, "in png_do_encode_alpha");
4395 :
4396 : if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
4397 : {
4398 : if (row_info->bit_depth == 8)
4399 : {
4400 : PNG_CONST png_bytep table = png_ptr->gamma_from_1;
4401 :
4402 : if (table != NULL)
4403 : {
4404 : PNG_CONST int step =
4405 : (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2;
4406 :
4407 : /* The alpha channel is the last component: */
4408 : row += step - 1;
4409 :
4410 : for (; row_width > 0; --row_width, row += step)
4411 : *row = table[*row];
4412 :
4413 : return;
4414 : }
4415 : }
4416 :
4417 : else if (row_info->bit_depth == 16)
4418 : {
4419 : PNG_CONST png_uint_16pp table = png_ptr->gamma_16_from_1;
4420 : PNG_CONST int gamma_shift = png_ptr->gamma_shift;
4421 :
4422 : if (table != NULL)
4423 : {
4424 : PNG_CONST int step =
4425 : (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4;
4426 :
4427 : /* The alpha channel is the last component: */
4428 : row += step - 2;
4429 :
4430 : for (; row_width > 0; --row_width, row += step)
4431 : {
4432 : png_uint_16 v;
4433 :
4434 : v = table[*(row + 1) >> gamma_shift][*row];
4435 : *row = (png_byte)((v >> 8) & 0xff);
4436 : *(row + 1) = (png_byte)(v & 0xff);
4437 : }
4438 :
4439 : return;
4440 : }
4441 : }
4442 : }
4443 :
4444 : /* Only get to here if called with a weird row_info; no harm has been done,
4445 : * so just issue a warning.
4446 : */
4447 : png_warning(png_ptr, "png_do_encode_alpha: unexpected call");
4448 : }
4449 : #endif
4450 :
4451 : #ifdef PNG_READ_EXPAND_SUPPORTED
4452 : /* Expands a palette row to an RGB or RGBA row depending
4453 : * upon whether you supply trans and num_trans.
4454 : */
4455 : void /* PRIVATE */
4456 0 : png_do_expand_palette(png_row_infop row_info, png_bytep row,
4457 : png_const_colorp palette, png_const_bytep trans_alpha, int num_trans)
4458 : {
4459 : int shift, value;
4460 : png_bytep sp, dp;
4461 : png_uint_32 i;
4462 0 : png_uint_32 row_width=row_info->width;
4463 :
4464 : png_debug(1, "in png_do_expand_palette");
4465 :
4466 0 : if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
4467 : {
4468 0 : if (row_info->bit_depth < 8)
4469 : {
4470 0 : switch (row_info->bit_depth)
4471 : {
4472 : case 1:
4473 : {
4474 0 : sp = row + (png_size_t)((row_width - 1) >> 3);
4475 0 : dp = row + (png_size_t)row_width - 1;
4476 0 : shift = 7 - (int)((row_width + 7) & 0x07);
4477 0 : for (i = 0; i < row_width; i++)
4478 : {
4479 0 : if ((*sp >> shift) & 0x01)
4480 0 : *dp = 1;
4481 :
4482 : else
4483 0 : *dp = 0;
4484 :
4485 0 : if (shift == 7)
4486 : {
4487 0 : shift = 0;
4488 0 : sp--;
4489 : }
4490 :
4491 : else
4492 0 : shift++;
4493 :
4494 0 : dp--;
4495 : }
4496 0 : break;
4497 : }
4498 :
4499 : case 2:
4500 : {
4501 0 : sp = row + (png_size_t)((row_width - 1) >> 2);
4502 0 : dp = row + (png_size_t)row_width - 1;
4503 0 : shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
4504 0 : for (i = 0; i < row_width; i++)
4505 : {
4506 0 : value = (*sp >> shift) & 0x03;
4507 0 : *dp = (png_byte)value;
4508 0 : if (shift == 6)
4509 : {
4510 0 : shift = 0;
4511 0 : sp--;
4512 : }
4513 :
4514 : else
4515 0 : shift += 2;
4516 :
4517 0 : dp--;
4518 : }
4519 0 : break;
4520 : }
4521 :
4522 : case 4:
4523 : {
4524 0 : sp = row + (png_size_t)((row_width - 1) >> 1);
4525 0 : dp = row + (png_size_t)row_width - 1;
4526 0 : shift = (int)((row_width & 0x01) << 2);
4527 0 : for (i = 0; i < row_width; i++)
4528 : {
4529 0 : value = (*sp >> shift) & 0x0f;
4530 0 : *dp = (png_byte)value;
4531 0 : if (shift == 4)
4532 : {
4533 0 : shift = 0;
4534 0 : sp--;
4535 : }
4536 :
4537 : else
4538 0 : shift += 4;
4539 :
4540 0 : dp--;
4541 : }
4542 0 : break;
4543 : }
4544 :
4545 : default:
4546 0 : break;
4547 : }
4548 0 : row_info->bit_depth = 8;
4549 0 : row_info->pixel_depth = 8;
4550 0 : row_info->rowbytes = row_width;
4551 : }
4552 :
4553 0 : if (row_info->bit_depth == 8)
4554 : {
4555 : {
4556 0 : if (num_trans > 0)
4557 : {
4558 0 : sp = row + (png_size_t)row_width - 1;
4559 0 : dp = row + (png_size_t)(row_width << 2) - 1;
4560 :
4561 0 : for (i = 0; i < row_width; i++)
4562 : {
4563 0 : if ((int)(*sp) >= num_trans)
4564 0 : *dp-- = 0xff;
4565 :
4566 : else
4567 0 : *dp-- = trans_alpha[*sp];
4568 :
4569 0 : *dp-- = palette[*sp].blue;
4570 0 : *dp-- = palette[*sp].green;
4571 0 : *dp-- = palette[*sp].red;
4572 0 : sp--;
4573 : }
4574 0 : row_info->bit_depth = 8;
4575 0 : row_info->pixel_depth = 32;
4576 0 : row_info->rowbytes = row_width * 4;
4577 0 : row_info->color_type = 6;
4578 0 : row_info->channels = 4;
4579 : }
4580 :
4581 : else
4582 : {
4583 0 : sp = row + (png_size_t)row_width - 1;
4584 0 : dp = row + (png_size_t)(row_width * 3) - 1;
4585 :
4586 0 : for (i = 0; i < row_width; i++)
4587 : {
4588 0 : *dp-- = palette[*sp].blue;
4589 0 : *dp-- = palette[*sp].green;
4590 0 : *dp-- = palette[*sp].red;
4591 0 : sp--;
4592 : }
4593 :
4594 0 : row_info->bit_depth = 8;
4595 0 : row_info->pixel_depth = 24;
4596 0 : row_info->rowbytes = row_width * 3;
4597 0 : row_info->color_type = 2;
4598 0 : row_info->channels = 3;
4599 : }
4600 : }
4601 : }
4602 : }
4603 0 : }
4604 :
4605 : /* If the bit depth < 8, it is expanded to 8. Also, if the already
4606 : * expanded transparency value is supplied, an alpha channel is built.
4607 : */
4608 : void /* PRIVATE */
4609 195 : png_do_expand(png_row_infop row_info, png_bytep row,
4610 : png_const_color_16p trans_color)
4611 : {
4612 : int shift, value;
4613 : png_bytep sp, dp;
4614 : png_uint_32 i;
4615 195 : png_uint_32 row_width=row_info->width;
4616 :
4617 : png_debug(1, "in png_do_expand");
4618 :
4619 : {
4620 195 : if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
4621 : {
4622 0 : png_uint_16 gray = (png_uint_16)(trans_color ? trans_color->gray : 0);
4623 :
4624 0 : if (row_info->bit_depth < 8)
4625 : {
4626 0 : switch (row_info->bit_depth)
4627 : {
4628 : case 1:
4629 : {
4630 0 : gray = (png_uint_16)((gray & 0x01) * 0xff);
4631 0 : sp = row + (png_size_t)((row_width - 1) >> 3);
4632 0 : dp = row + (png_size_t)row_width - 1;
4633 0 : shift = 7 - (int)((row_width + 7) & 0x07);
4634 0 : for (i = 0; i < row_width; i++)
4635 : {
4636 0 : if ((*sp >> shift) & 0x01)
4637 0 : *dp = 0xff;
4638 :
4639 : else
4640 0 : *dp = 0;
4641 :
4642 0 : if (shift == 7)
4643 : {
4644 0 : shift = 0;
4645 0 : sp--;
4646 : }
4647 :
4648 : else
4649 0 : shift++;
4650 :
4651 0 : dp--;
4652 : }
4653 0 : break;
4654 : }
4655 :
4656 : case 2:
4657 : {
4658 0 : gray = (png_uint_16)((gray & 0x03) * 0x55);
4659 0 : sp = row + (png_size_t)((row_width - 1) >> 2);
4660 0 : dp = row + (png_size_t)row_width - 1;
4661 0 : shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
4662 0 : for (i = 0; i < row_width; i++)
4663 : {
4664 0 : value = (*sp >> shift) & 0x03;
4665 0 : *dp = (png_byte)(value | (value << 2) | (value << 4) |
4666 0 : (value << 6));
4667 0 : if (shift == 6)
4668 : {
4669 0 : shift = 0;
4670 0 : sp--;
4671 : }
4672 :
4673 : else
4674 0 : shift += 2;
4675 :
4676 0 : dp--;
4677 : }
4678 0 : break;
4679 : }
4680 :
4681 : case 4:
4682 : {
4683 0 : gray = (png_uint_16)((gray & 0x0f) * 0x11);
4684 0 : sp = row + (png_size_t)((row_width - 1) >> 1);
4685 0 : dp = row + (png_size_t)row_width - 1;
4686 0 : shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
4687 0 : for (i = 0; i < row_width; i++)
4688 : {
4689 0 : value = (*sp >> shift) & 0x0f;
4690 0 : *dp = (png_byte)(value | (value << 4));
4691 0 : if (shift == 4)
4692 : {
4693 0 : shift = 0;
4694 0 : sp--;
4695 : }
4696 :
4697 : else
4698 0 : shift = 4;
4699 :
4700 0 : dp--;
4701 : }
4702 0 : break;
4703 : }
4704 :
4705 : default:
4706 0 : break;
4707 : }
4708 :
4709 0 : row_info->bit_depth = 8;
4710 0 : row_info->pixel_depth = 8;
4711 0 : row_info->rowbytes = row_width;
4712 : }
4713 :
4714 0 : if (trans_color != NULL)
4715 : {
4716 0 : if (row_info->bit_depth == 8)
4717 : {
4718 0 : gray = gray & 0xff;
4719 0 : sp = row + (png_size_t)row_width - 1;
4720 0 : dp = row + (png_size_t)(row_width << 1) - 1;
4721 :
4722 0 : for (i = 0; i < row_width; i++)
4723 : {
4724 0 : if (*sp == gray)
4725 0 : *dp-- = 0;
4726 :
4727 : else
4728 0 : *dp-- = 0xff;
4729 :
4730 0 : *dp-- = *sp--;
4731 : }
4732 : }
4733 :
4734 0 : else if (row_info->bit_depth == 16)
4735 : {
4736 0 : png_byte gray_high = (png_byte)((gray >> 8) & 0xff);
4737 0 : png_byte gray_low = (png_byte)(gray & 0xff);
4738 0 : sp = row + row_info->rowbytes - 1;
4739 0 : dp = row + (row_info->rowbytes << 1) - 1;
4740 0 : for (i = 0; i < row_width; i++)
4741 : {
4742 0 : if (*(sp - 1) == gray_high && *(sp) == gray_low)
4743 : {
4744 0 : *dp-- = 0;
4745 0 : *dp-- = 0;
4746 : }
4747 :
4748 : else
4749 : {
4750 0 : *dp-- = 0xff;
4751 0 : *dp-- = 0xff;
4752 : }
4753 :
4754 0 : *dp-- = *sp--;
4755 0 : *dp-- = *sp--;
4756 : }
4757 : }
4758 :
4759 0 : row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
4760 0 : row_info->channels = 2;
4761 0 : row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
4762 0 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
4763 : row_width);
4764 : }
4765 : }
4766 195 : else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_color)
4767 : {
4768 0 : if (row_info->bit_depth == 8)
4769 : {
4770 0 : png_byte red = (png_byte)(trans_color->red & 0xff);
4771 0 : png_byte green = (png_byte)(trans_color->green & 0xff);
4772 0 : png_byte blue = (png_byte)(trans_color->blue & 0xff);
4773 0 : sp = row + (png_size_t)row_info->rowbytes - 1;
4774 0 : dp = row + (png_size_t)(row_width << 2) - 1;
4775 0 : for (i = 0; i < row_width; i++)
4776 : {
4777 0 : if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
4778 0 : *dp-- = 0;
4779 :
4780 : else
4781 0 : *dp-- = 0xff;
4782 :
4783 0 : *dp-- = *sp--;
4784 0 : *dp-- = *sp--;
4785 0 : *dp-- = *sp--;
4786 : }
4787 : }
4788 0 : else if (row_info->bit_depth == 16)
4789 : {
4790 0 : png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
4791 0 : png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
4792 0 : png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
4793 0 : png_byte red_low = (png_byte)(trans_color->red & 0xff);
4794 0 : png_byte green_low = (png_byte)(trans_color->green & 0xff);
4795 0 : png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
4796 0 : sp = row + row_info->rowbytes - 1;
4797 0 : dp = row + (png_size_t)(row_width << 3) - 1;
4798 0 : for (i = 0; i < row_width; i++)
4799 : {
4800 0 : if (*(sp - 5) == red_high &&
4801 0 : *(sp - 4) == red_low &&
4802 0 : *(sp - 3) == green_high &&
4803 0 : *(sp - 2) == green_low &&
4804 0 : *(sp - 1) == blue_high &&
4805 0 : *(sp ) == blue_low)
4806 : {
4807 0 : *dp-- = 0;
4808 0 : *dp-- = 0;
4809 : }
4810 :
4811 : else
4812 : {
4813 0 : *dp-- = 0xff;
4814 0 : *dp-- = 0xff;
4815 : }
4816 :
4817 0 : *dp-- = *sp--;
4818 0 : *dp-- = *sp--;
4819 0 : *dp-- = *sp--;
4820 0 : *dp-- = *sp--;
4821 0 : *dp-- = *sp--;
4822 0 : *dp-- = *sp--;
4823 : }
4824 : }
4825 0 : row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
4826 0 : row_info->channels = 4;
4827 0 : row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
4828 0 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
4829 : }
4830 : }
4831 195 : }
4832 : #endif
4833 :
4834 : #ifdef PNG_READ_EXPAND_16_SUPPORTED
4835 : /* If the bit depth is 8 and the color type is not a palette type expand the
4836 : * whole row to 16 bits. Has no effect otherwise.
4837 : */
4838 : void /* PRIVATE */
4839 : png_do_expand_16(png_row_infop row_info, png_bytep row)
4840 : {
4841 : if (row_info->bit_depth == 8 &&
4842 : row_info->color_type != PNG_COLOR_TYPE_PALETTE)
4843 : {
4844 : /* The row have a sequence of bytes containing [0..255] and we need
4845 : * to turn it into another row containing [0..65535], to do this we
4846 : * calculate:
4847 : *
4848 : * (input / 255) * 65535
4849 : *
4850 : * Which happens to be exactly input * 257 and this can be achieved
4851 : * simply by byte replication in place (copying backwards).
4852 : */
4853 : png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */
4854 : png_byte *dp = sp + row_info->rowbytes; /* destination, end + 1 */
4855 : while (dp > sp)
4856 : dp[-2] = dp[-1] = *--sp, dp -= 2;
4857 :
4858 : row_info->rowbytes *= 2;
4859 : row_info->bit_depth = 16;
4860 : row_info->pixel_depth = (png_byte)(row_info->channels * 16);
4861 : }
4862 : }
4863 : #endif
4864 :
4865 : #ifdef PNG_READ_QUANTIZE_SUPPORTED
4866 : void /* PRIVATE */
4867 : png_do_quantize(png_row_infop row_info, png_bytep row,
4868 : png_const_bytep palette_lookup, png_const_bytep quantize_lookup)
4869 : {
4870 : png_bytep sp, dp;
4871 : png_uint_32 i;
4872 : png_uint_32 row_width=row_info->width;
4873 :
4874 : png_debug(1, "in png_do_quantize");
4875 :
4876 : if (row_info->bit_depth == 8)
4877 : {
4878 : if (row_info->color_type == PNG_COLOR_TYPE_RGB && palette_lookup)
4879 : {
4880 : int r, g, b, p;
4881 : sp = row;
4882 : dp = row;
4883 : for (i = 0; i < row_width; i++)
4884 : {
4885 : r = *sp++;
4886 : g = *sp++;
4887 : b = *sp++;
4888 :
4889 : /* This looks real messy, but the compiler will reduce
4890 : * it down to a reasonable formula. For example, with
4891 : * 5 bits per color, we get:
4892 : * p = (((r >> 3) & 0x1f) << 10) |
4893 : * (((g >> 3) & 0x1f) << 5) |
4894 : * ((b >> 3) & 0x1f);
4895 : */
4896 : p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
4897 : ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
4898 : (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
4899 : (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
4900 : ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
4901 : (PNG_QUANTIZE_BLUE_BITS)) |
4902 : ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
4903 : ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
4904 :
4905 : *dp++ = palette_lookup[p];
4906 : }
4907 :
4908 : row_info->color_type = PNG_COLOR_TYPE_PALETTE;
4909 : row_info->channels = 1;
4910 : row_info->pixel_depth = row_info->bit_depth;
4911 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
4912 : }
4913 :
4914 : else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
4915 : palette_lookup != NULL)
4916 : {
4917 : int r, g, b, p;
4918 : sp = row;
4919 : dp = row;
4920 : for (i = 0; i < row_width; i++)
4921 : {
4922 : r = *sp++;
4923 : g = *sp++;
4924 : b = *sp++;
4925 : sp++;
4926 :
4927 : p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
4928 : ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
4929 : (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
4930 : (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
4931 : ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
4932 : (PNG_QUANTIZE_BLUE_BITS)) |
4933 : ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
4934 : ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
4935 :
4936 : *dp++ = palette_lookup[p];
4937 : }
4938 :
4939 : row_info->color_type = PNG_COLOR_TYPE_PALETTE;
4940 : row_info->channels = 1;
4941 : row_info->pixel_depth = row_info->bit_depth;
4942 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
4943 : }
4944 :
4945 : else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
4946 : quantize_lookup)
4947 : {
4948 : sp = row;
4949 :
4950 : for (i = 0; i < row_width; i++, sp++)
4951 : {
4952 : *sp = quantize_lookup[*sp];
4953 : }
4954 : }
4955 : }
4956 : }
4957 : #endif /* PNG_READ_QUANTIZE_SUPPORTED */
4958 : #endif /* PNG_READ_TRANSFORMS_SUPPORTED */
4959 :
4960 : #ifdef PNG_MNG_FEATURES_SUPPORTED
4961 : /* Undoes intrapixel differencing */
4962 : void /* PRIVATE */
4963 : png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
4964 : {
4965 : png_debug(1, "in png_do_read_intrapixel");
4966 :
4967 : if (
4968 : (row_info->color_type & PNG_COLOR_MASK_COLOR))
4969 : {
4970 : int bytes_per_pixel;
4971 : png_uint_32 row_width = row_info->width;
4972 :
4973 : if (row_info->bit_depth == 8)
4974 : {
4975 : png_bytep rp;
4976 : png_uint_32 i;
4977 :
4978 : if (row_info->color_type == PNG_COLOR_TYPE_RGB)
4979 : bytes_per_pixel = 3;
4980 :
4981 : else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
4982 : bytes_per_pixel = 4;
4983 :
4984 : else
4985 : return;
4986 :
4987 : for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
4988 : {
4989 : *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
4990 : *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
4991 : }
4992 : }
4993 : else if (row_info->bit_depth == 16)
4994 : {
4995 : png_bytep rp;
4996 : png_uint_32 i;
4997 :
4998 : if (row_info->color_type == PNG_COLOR_TYPE_RGB)
4999 : bytes_per_pixel = 6;
5000 :
5001 : else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
5002 : bytes_per_pixel = 8;
5003 :
5004 : else
5005 : return;
5006 :
5007 : for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
5008 : {
5009 : png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
5010 : png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
5011 : png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
5012 : png_uint_32 red = (s0 + s1 + 65536) & 0xffff;
5013 : png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
5014 : *(rp ) = (png_byte)((red >> 8) & 0xff);
5015 : *(rp + 1) = (png_byte)(red & 0xff);
5016 : *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
5017 : *(rp + 5) = (png_byte)(blue & 0xff);
5018 : }
5019 : }
5020 : }
5021 : }
5022 : #endif /* PNG_MNG_FEATURES_SUPPORTED */
5023 : #endif /* PNG_READ_SUPPORTED */
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