Line data Source code
1 :
2 : /* pngrtran.c - transforms the data in a row for PNG readers
3 : *
4 : * Last changed in libpng 1.6.29 [March 16, 2017]
5 : * Copyright (c) 1998-2002,2004,2006-2017 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 0 : png_set_crc_action(png_structrp png_ptr, int crit_action, int ancil_action)
26 : {
27 : png_debug(1, "in png_set_crc_action");
28 :
29 0 : if (png_ptr == NULL)
30 0 : return;
31 :
32 : /* Tell libpng how we react to CRC errors in critical chunks */
33 0 : switch (crit_action)
34 : {
35 : case PNG_CRC_NO_CHANGE: /* Leave setting as is */
36 0 : 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 0 : 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 0 : 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 0 : png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
79 0 : png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
80 0 : 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_TRANSFORMS_SUPPORTED
92 : /* Is it OK to set a transformation now? Only if png_start_read_image or
93 : * png_read_update_info have not been called. It is not necessary for the IHDR
94 : * to have been read in all cases; the need_IHDR parameter allows for this
95 : * check too.
96 : */
97 : static int
98 89 : png_rtran_ok(png_structrp png_ptr, int need_IHDR)
99 : {
100 89 : if (png_ptr != NULL)
101 : {
102 89 : if ((png_ptr->flags & PNG_FLAG_ROW_INIT) != 0)
103 0 : png_app_error(png_ptr,
104 : "invalid after png_start_read_image or png_read_update_info");
105 :
106 89 : else if (need_IHDR && (png_ptr->mode & PNG_HAVE_IHDR) == 0)
107 0 : png_app_error(png_ptr, "invalid before the PNG header has been read");
108 :
109 : else
110 : {
111 : /* Turn on failure to initialize correctly for all transforms. */
112 89 : png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
113 :
114 89 : return 1; /* Ok */
115 : }
116 : }
117 :
118 0 : return 0; /* no png_error possible! */
119 : }
120 : #endif
121 :
122 : #ifdef PNG_READ_BACKGROUND_SUPPORTED
123 : /* Handle alpha and tRNS via a background color */
124 : void PNGFAPI
125 : png_set_background_fixed(png_structrp png_ptr,
126 : png_const_color_16p background_color, int background_gamma_code,
127 : int need_expand, png_fixed_point background_gamma)
128 : {
129 : png_debug(1, "in png_set_background_fixed");
130 :
131 : if (png_rtran_ok(png_ptr, 0) == 0 || background_color == NULL)
132 : return;
133 :
134 : if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
135 : {
136 : png_warning(png_ptr, "Application must supply a known background gamma");
137 : return;
138 : }
139 :
140 : png_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA;
141 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
142 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
143 :
144 : png_ptr->background = *background_color;
145 : png_ptr->background_gamma = background_gamma;
146 : png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
147 : if (need_expand != 0)
148 : png_ptr->transformations |= PNG_BACKGROUND_EXPAND;
149 : else
150 : png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
151 : }
152 :
153 : # ifdef PNG_FLOATING_POINT_SUPPORTED
154 : void PNGAPI
155 : png_set_background(png_structrp png_ptr,
156 : png_const_color_16p background_color, int background_gamma_code,
157 : int need_expand, double background_gamma)
158 : {
159 : png_set_background_fixed(png_ptr, background_color, background_gamma_code,
160 : need_expand, png_fixed(png_ptr, background_gamma, "png_set_background"));
161 : }
162 : # endif /* FLOATING_POINT */
163 : #endif /* READ_BACKGROUND */
164 :
165 : /* Scale 16-bit depth files to 8-bit depth. If both of these are set then the
166 : * one that pngrtran does first (scale) happens. This is necessary to allow the
167 : * TRANSFORM and API behavior to be somewhat consistent, and it's simpler.
168 : */
169 : #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
170 : void PNGAPI
171 0 : png_set_scale_16(png_structrp png_ptr)
172 : {
173 : png_debug(1, "in png_set_scale_16");
174 :
175 0 : if (png_rtran_ok(png_ptr, 0) == 0)
176 0 : return;
177 :
178 0 : png_ptr->transformations |= PNG_SCALE_16_TO_8;
179 : }
180 : #endif
181 :
182 : #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
183 : /* Chop 16-bit depth files to 8-bit depth */
184 : void PNGAPI
185 : png_set_strip_16(png_structrp png_ptr)
186 : {
187 : png_debug(1, "in png_set_strip_16");
188 :
189 : if (png_rtran_ok(png_ptr, 0) == 0)
190 : return;
191 :
192 : png_ptr->transformations |= PNG_16_TO_8;
193 : }
194 : #endif
195 :
196 : #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
197 : void PNGAPI
198 : png_set_strip_alpha(png_structrp png_ptr)
199 : {
200 : png_debug(1, "in png_set_strip_alpha");
201 :
202 : if (png_rtran_ok(png_ptr, 0) == 0)
203 : return;
204 :
205 : png_ptr->transformations |= PNG_STRIP_ALPHA;
206 : }
207 : #endif
208 :
209 : #if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED)
210 : static png_fixed_point
211 46 : translate_gamma_flags(png_structrp png_ptr, png_fixed_point output_gamma,
212 : int is_screen)
213 : {
214 : /* Check for flag values. The main reason for having the old Mac value as a
215 : * flag is that it is pretty near impossible to work out what the correct
216 : * value is from Apple documentation - a working Mac system is needed to
217 : * discover the value!
218 : */
219 46 : if (output_gamma == PNG_DEFAULT_sRGB ||
220 : output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB)
221 : {
222 : /* If there is no sRGB support this just sets the gamma to the standard
223 : * sRGB value. (This is a side effect of using this function!)
224 : */
225 : # ifdef PNG_READ_sRGB_SUPPORTED
226 0 : png_ptr->flags |= PNG_FLAG_ASSUME_sRGB;
227 : # else
228 : PNG_UNUSED(png_ptr)
229 : # endif
230 0 : if (is_screen != 0)
231 0 : output_gamma = PNG_GAMMA_sRGB;
232 : else
233 0 : output_gamma = PNG_GAMMA_sRGB_INVERSE;
234 : }
235 :
236 46 : else if (output_gamma == PNG_GAMMA_MAC_18 ||
237 : output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18)
238 : {
239 0 : if (is_screen != 0)
240 0 : output_gamma = PNG_GAMMA_MAC_OLD;
241 : else
242 0 : output_gamma = PNG_GAMMA_MAC_INVERSE;
243 : }
244 :
245 46 : return output_gamma;
246 : }
247 :
248 : # ifdef PNG_FLOATING_POINT_SUPPORTED
249 : static png_fixed_point
250 46 : convert_gamma_value(png_structrp png_ptr, double output_gamma)
251 : {
252 : /* The following silently ignores cases where fixed point (times 100,000)
253 : * gamma values are passed to the floating point API. This is safe and it
254 : * means the fixed point constants work just fine with the floating point
255 : * API. The alternative would just lead to undetected errors and spurious
256 : * bug reports. Negative values fail inside the _fixed API unless they
257 : * correspond to the flag values.
258 : */
259 46 : if (output_gamma > 0 && output_gamma < 128)
260 46 : output_gamma *= PNG_FP_1;
261 :
262 : /* This preserves -1 and -2 exactly: */
263 46 : output_gamma = floor(output_gamma + .5);
264 :
265 46 : if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN)
266 0 : png_fixed_error(png_ptr, "gamma value");
267 :
268 46 : return (png_fixed_point)output_gamma;
269 : }
270 : # endif
271 : #endif /* READ_ALPHA_MODE || READ_GAMMA */
272 :
273 : #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
274 : void PNGFAPI
275 : png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
276 : png_fixed_point output_gamma)
277 : {
278 : int compose = 0;
279 : png_fixed_point file_gamma;
280 :
281 : png_debug(1, "in png_set_alpha_mode");
282 :
283 : if (png_rtran_ok(png_ptr, 0) == 0)
284 : return;
285 :
286 : output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
287 :
288 : /* Validate the value to ensure it is in a reasonable range. The value
289 : * is expected to be 1 or greater, but this range test allows for some
290 : * viewing correction values. The intent is to weed out users of this API
291 : * who use the inverse of the gamma value accidentally! Since some of these
292 : * values are reasonable this may have to be changed:
293 : *
294 : * 1.6.x: changed from 0.07..3 to 0.01..100 (to accomodate the optimal 16-bit
295 : * gamma of 36, and its reciprocal.)
296 : */
297 : if (output_gamma < 1000 || output_gamma > 10000000)
298 : png_error(png_ptr, "output gamma out of expected range");
299 :
300 : /* The default file gamma is the inverse of the output gamma; the output
301 : * gamma may be changed below so get the file value first:
302 : */
303 : file_gamma = png_reciprocal(output_gamma);
304 :
305 : /* There are really 8 possibilities here, composed of any combination
306 : * of:
307 : *
308 : * premultiply the color channels
309 : * do not encode non-opaque pixels
310 : * encode the alpha as well as the color channels
311 : *
312 : * The differences disappear if the input/output ('screen') gamma is 1.0,
313 : * because then the encoding is a no-op and there is only the choice of
314 : * premultiplying the color channels or not.
315 : *
316 : * png_set_alpha_mode and png_set_background interact because both use
317 : * png_compose to do the work. Calling both is only useful when
318 : * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along
319 : * with a default gamma value. Otherwise PNG_COMPOSE must not be set.
320 : */
321 : switch (mode)
322 : {
323 : case PNG_ALPHA_PNG: /* default: png standard */
324 : /* No compose, but it may be set by png_set_background! */
325 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
326 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
327 : break;
328 :
329 : case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */
330 : compose = 1;
331 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
332 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
333 : /* The output is linear: */
334 : output_gamma = PNG_FP_1;
335 : break;
336 :
337 : case PNG_ALPHA_OPTIMIZED: /* associated, non-opaque pixels linear */
338 : compose = 1;
339 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
340 : png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA;
341 : /* output_gamma records the encoding of opaque pixels! */
342 : break;
343 :
344 : case PNG_ALPHA_BROKEN: /* associated, non-linear, alpha encoded */
345 : compose = 1;
346 : png_ptr->transformations |= PNG_ENCODE_ALPHA;
347 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
348 : break;
349 :
350 : default:
351 : png_error(png_ptr, "invalid alpha mode");
352 : }
353 :
354 : /* Only set the default gamma if the file gamma has not been set (this has
355 : * the side effect that the gamma in a second call to png_set_alpha_mode will
356 : * be ignored.)
357 : */
358 : if (png_ptr->colorspace.gamma == 0)
359 : {
360 : png_ptr->colorspace.gamma = file_gamma;
361 : png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
362 : }
363 :
364 : /* But always set the output gamma: */
365 : png_ptr->screen_gamma = output_gamma;
366 :
367 : /* Finally, if pre-multiplying, set the background fields to achieve the
368 : * desired result.
369 : */
370 : if (compose != 0)
371 : {
372 : /* And obtain alpha pre-multiplication by composing on black: */
373 : memset(&png_ptr->background, 0, (sizeof png_ptr->background));
374 : png_ptr->background_gamma = png_ptr->colorspace.gamma; /* just in case */
375 : png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
376 : png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
377 :
378 : if ((png_ptr->transformations & PNG_COMPOSE) != 0)
379 : png_error(png_ptr,
380 : "conflicting calls to set alpha mode and background");
381 :
382 : png_ptr->transformations |= PNG_COMPOSE;
383 : }
384 : }
385 :
386 : # ifdef PNG_FLOATING_POINT_SUPPORTED
387 : void PNGAPI
388 : png_set_alpha_mode(png_structrp png_ptr, int mode, double output_gamma)
389 : {
390 : png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr,
391 : output_gamma));
392 : }
393 : # endif
394 : #endif
395 :
396 : #ifdef PNG_READ_QUANTIZE_SUPPORTED
397 : /* Dither file to 8-bit. Supply a palette, the current number
398 : * of elements in the palette, the maximum number of elements
399 : * allowed, and a histogram if possible. If the current number
400 : * of colors is greater than the maximum number, the palette will be
401 : * modified to fit in the maximum number. "full_quantize" indicates
402 : * whether we need a quantizing cube set up for RGB images, or if we
403 : * simply are reducing the number of colors in a paletted image.
404 : */
405 :
406 : typedef struct png_dsort_struct
407 : {
408 : struct png_dsort_struct * next;
409 : png_byte left;
410 : png_byte right;
411 : } png_dsort;
412 : typedef png_dsort * png_dsortp;
413 : typedef png_dsort * * png_dsortpp;
414 :
415 : void PNGAPI
416 : png_set_quantize(png_structrp png_ptr, png_colorp palette,
417 : int num_palette, int maximum_colors, png_const_uint_16p histogram,
418 : int full_quantize)
419 : {
420 : png_debug(1, "in png_set_quantize");
421 :
422 : if (png_rtran_ok(png_ptr, 0) == 0)
423 : return;
424 :
425 : png_ptr->transformations |= PNG_QUANTIZE;
426 :
427 : if (full_quantize == 0)
428 : {
429 : int i;
430 :
431 : png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr,
432 : (png_uint_32)((png_uint_32)num_palette * (sizeof (png_byte))));
433 : for (i = 0; i < num_palette; i++)
434 : png_ptr->quantize_index[i] = (png_byte)i;
435 : }
436 :
437 : if (num_palette > maximum_colors)
438 : {
439 : if (histogram != NULL)
440 : {
441 : /* This is easy enough, just throw out the least used colors.
442 : * Perhaps not the best solution, but good enough.
443 : */
444 :
445 : int i;
446 :
447 : /* Initialize an array to sort colors */
448 : png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr,
449 : (png_uint_32)((png_uint_32)num_palette * (sizeof (png_byte))));
450 :
451 : /* Initialize the quantize_sort array */
452 : for (i = 0; i < num_palette; i++)
453 : png_ptr->quantize_sort[i] = (png_byte)i;
454 :
455 : /* Find the least used palette entries by starting a
456 : * bubble sort, and running it until we have sorted
457 : * out enough colors. Note that we don't care about
458 : * sorting all the colors, just finding which are
459 : * least used.
460 : */
461 :
462 : for (i = num_palette - 1; i >= maximum_colors; i--)
463 : {
464 : int done; /* To stop early if the list is pre-sorted */
465 : int j;
466 :
467 : done = 1;
468 : for (j = 0; j < i; j++)
469 : {
470 : if (histogram[png_ptr->quantize_sort[j]]
471 : < histogram[png_ptr->quantize_sort[j + 1]])
472 : {
473 : png_byte t;
474 :
475 : t = png_ptr->quantize_sort[j];
476 : png_ptr->quantize_sort[j] = png_ptr->quantize_sort[j + 1];
477 : png_ptr->quantize_sort[j + 1] = t;
478 : done = 0;
479 : }
480 : }
481 :
482 : if (done != 0)
483 : break;
484 : }
485 :
486 : /* Swap the palette around, and set up a table, if necessary */
487 : if (full_quantize != 0)
488 : {
489 : int j = num_palette;
490 :
491 : /* Put all the useful colors within the max, but don't
492 : * move the others.
493 : */
494 : for (i = 0; i < maximum_colors; i++)
495 : {
496 : if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
497 : {
498 : do
499 : j--;
500 : while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
501 :
502 : palette[i] = palette[j];
503 : }
504 : }
505 : }
506 : else
507 : {
508 : int j = num_palette;
509 :
510 : /* Move all the used colors inside the max limit, and
511 : * develop a translation table.
512 : */
513 : for (i = 0; i < maximum_colors; i++)
514 : {
515 : /* Only move the colors we need to */
516 : if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
517 : {
518 : png_color tmp_color;
519 :
520 : do
521 : j--;
522 : while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
523 :
524 : tmp_color = palette[j];
525 : palette[j] = palette[i];
526 : palette[i] = tmp_color;
527 : /* Indicate where the color went */
528 : png_ptr->quantize_index[j] = (png_byte)i;
529 : png_ptr->quantize_index[i] = (png_byte)j;
530 : }
531 : }
532 :
533 : /* Find closest color for those colors we are not using */
534 : for (i = 0; i < num_palette; i++)
535 : {
536 : if ((int)png_ptr->quantize_index[i] >= maximum_colors)
537 : {
538 : int min_d, k, min_k, d_index;
539 :
540 : /* Find the closest color to one we threw out */
541 : d_index = png_ptr->quantize_index[i];
542 : min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
543 : for (k = 1, min_k = 0; k < maximum_colors; k++)
544 : {
545 : int d;
546 :
547 : d = PNG_COLOR_DIST(palette[d_index], palette[k]);
548 :
549 : if (d < min_d)
550 : {
551 : min_d = d;
552 : min_k = k;
553 : }
554 : }
555 : /* Point to closest color */
556 : png_ptr->quantize_index[i] = (png_byte)min_k;
557 : }
558 : }
559 : }
560 : png_free(png_ptr, png_ptr->quantize_sort);
561 : png_ptr->quantize_sort = NULL;
562 : }
563 : else
564 : {
565 : /* This is much harder to do simply (and quickly). Perhaps
566 : * we need to go through a median cut routine, but those
567 : * don't always behave themselves with only a few colors
568 : * as input. So we will just find the closest two colors,
569 : * and throw out one of them (chosen somewhat randomly).
570 : * [We don't understand this at all, so if someone wants to
571 : * work on improving it, be our guest - AED, GRP]
572 : */
573 : int i;
574 : int max_d;
575 : int num_new_palette;
576 : png_dsortp t;
577 : png_dsortpp hash;
578 :
579 : t = NULL;
580 :
581 : /* Initialize palette index arrays */
582 : png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
583 : (png_uint_32)((png_uint_32)num_palette * (sizeof (png_byte))));
584 : png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
585 : (png_uint_32)((png_uint_32)num_palette * (sizeof (png_byte))));
586 :
587 : /* Initialize the sort array */
588 : for (i = 0; i < num_palette; i++)
589 : {
590 : png_ptr->index_to_palette[i] = (png_byte)i;
591 : png_ptr->palette_to_index[i] = (png_byte)i;
592 : }
593 :
594 : hash = (png_dsortpp)png_calloc(png_ptr, (png_uint_32)(769 *
595 : (sizeof (png_dsortp))));
596 :
597 : num_new_palette = num_palette;
598 :
599 : /* Initial wild guess at how far apart the farthest pixel
600 : * pair we will be eliminating will be. Larger
601 : * numbers mean more areas will be allocated, Smaller
602 : * numbers run the risk of not saving enough data, and
603 : * having to do this all over again.
604 : *
605 : * I have not done extensive checking on this number.
606 : */
607 : max_d = 96;
608 :
609 : while (num_new_palette > maximum_colors)
610 : {
611 : for (i = 0; i < num_new_palette - 1; i++)
612 : {
613 : int j;
614 :
615 : for (j = i + 1; j < num_new_palette; j++)
616 : {
617 : int d;
618 :
619 : d = PNG_COLOR_DIST(palette[i], palette[j]);
620 :
621 : if (d <= max_d)
622 : {
623 :
624 : t = (png_dsortp)png_malloc_warn(png_ptr,
625 : (png_uint_32)(sizeof (png_dsort)));
626 :
627 : if (t == NULL)
628 : break;
629 :
630 : t->next = hash[d];
631 : t->left = (png_byte)i;
632 : t->right = (png_byte)j;
633 : hash[d] = t;
634 : }
635 : }
636 : if (t == NULL)
637 : break;
638 : }
639 :
640 : if (t != NULL)
641 : for (i = 0; i <= max_d; i++)
642 : {
643 : if (hash[i] != NULL)
644 : {
645 : png_dsortp p;
646 :
647 : for (p = hash[i]; p; p = p->next)
648 : {
649 : if ((int)png_ptr->index_to_palette[p->left]
650 : < num_new_palette &&
651 : (int)png_ptr->index_to_palette[p->right]
652 : < num_new_palette)
653 : {
654 : int j, next_j;
655 :
656 : if (num_new_palette & 0x01)
657 : {
658 : j = p->left;
659 : next_j = p->right;
660 : }
661 : else
662 : {
663 : j = p->right;
664 : next_j = p->left;
665 : }
666 :
667 : num_new_palette--;
668 : palette[png_ptr->index_to_palette[j]]
669 : = palette[num_new_palette];
670 : if (full_quantize == 0)
671 : {
672 : int k;
673 :
674 : for (k = 0; k < num_palette; k++)
675 : {
676 : if (png_ptr->quantize_index[k] ==
677 : png_ptr->index_to_palette[j])
678 : png_ptr->quantize_index[k] =
679 : png_ptr->index_to_palette[next_j];
680 :
681 : if ((int)png_ptr->quantize_index[k] ==
682 : num_new_palette)
683 : png_ptr->quantize_index[k] =
684 : png_ptr->index_to_palette[j];
685 : }
686 : }
687 :
688 : png_ptr->index_to_palette[png_ptr->palette_to_index
689 : [num_new_palette]] = png_ptr->index_to_palette[j];
690 :
691 : png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
692 : = png_ptr->palette_to_index[num_new_palette];
693 :
694 : png_ptr->index_to_palette[j] =
695 : (png_byte)num_new_palette;
696 :
697 : png_ptr->palette_to_index[num_new_palette] =
698 : (png_byte)j;
699 : }
700 : if (num_new_palette <= maximum_colors)
701 : break;
702 : }
703 : if (num_new_palette <= maximum_colors)
704 : break;
705 : }
706 : }
707 :
708 : for (i = 0; i < 769; i++)
709 : {
710 : if (hash[i] != NULL)
711 : {
712 : png_dsortp p = hash[i];
713 : while (p)
714 : {
715 : t = p->next;
716 : png_free(png_ptr, p);
717 : p = t;
718 : }
719 : }
720 : hash[i] = 0;
721 : }
722 : max_d += 96;
723 : }
724 : png_free(png_ptr, hash);
725 : png_free(png_ptr, png_ptr->palette_to_index);
726 : png_free(png_ptr, png_ptr->index_to_palette);
727 : png_ptr->palette_to_index = NULL;
728 : png_ptr->index_to_palette = NULL;
729 : }
730 : num_palette = maximum_colors;
731 : }
732 : if (png_ptr->palette == NULL)
733 : {
734 : png_ptr->palette = palette;
735 : }
736 : png_ptr->num_palette = (png_uint_16)num_palette;
737 :
738 : if (full_quantize != 0)
739 : {
740 : int i;
741 : png_bytep distance;
742 : int total_bits = PNG_QUANTIZE_RED_BITS + PNG_QUANTIZE_GREEN_BITS +
743 : PNG_QUANTIZE_BLUE_BITS;
744 : int num_red = (1 << PNG_QUANTIZE_RED_BITS);
745 : int num_green = (1 << PNG_QUANTIZE_GREEN_BITS);
746 : int num_blue = (1 << PNG_QUANTIZE_BLUE_BITS);
747 : png_size_t num_entries = ((png_size_t)1 << total_bits);
748 :
749 : png_ptr->palette_lookup = (png_bytep)png_calloc(png_ptr,
750 : (png_uint_32)(num_entries * (sizeof (png_byte))));
751 :
752 : distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries *
753 : (sizeof (png_byte))));
754 :
755 : memset(distance, 0xff, num_entries * (sizeof (png_byte)));
756 :
757 : for (i = 0; i < num_palette; i++)
758 : {
759 : int ir, ig, ib;
760 : int r = (palette[i].red >> (8 - PNG_QUANTIZE_RED_BITS));
761 : int g = (palette[i].green >> (8 - PNG_QUANTIZE_GREEN_BITS));
762 : int b = (palette[i].blue >> (8 - PNG_QUANTIZE_BLUE_BITS));
763 :
764 : for (ir = 0; ir < num_red; ir++)
765 : {
766 : /* int dr = abs(ir - r); */
767 : int dr = ((ir > r) ? ir - r : r - ir);
768 : int index_r = (ir << (PNG_QUANTIZE_BLUE_BITS +
769 : PNG_QUANTIZE_GREEN_BITS));
770 :
771 : for (ig = 0; ig < num_green; ig++)
772 : {
773 : /* int dg = abs(ig - g); */
774 : int dg = ((ig > g) ? ig - g : g - ig);
775 : int dt = dr + dg;
776 : int dm = ((dr > dg) ? dr : dg);
777 : int index_g = index_r | (ig << PNG_QUANTIZE_BLUE_BITS);
778 :
779 : for (ib = 0; ib < num_blue; ib++)
780 : {
781 : int d_index = index_g | ib;
782 : /* int db = abs(ib - b); */
783 : int db = ((ib > b) ? ib - b : b - ib);
784 : int dmax = ((dm > db) ? dm : db);
785 : int d = dmax + dt + db;
786 :
787 : if (d < (int)distance[d_index])
788 : {
789 : distance[d_index] = (png_byte)d;
790 : png_ptr->palette_lookup[d_index] = (png_byte)i;
791 : }
792 : }
793 : }
794 : }
795 : }
796 :
797 : png_free(png_ptr, distance);
798 : }
799 : }
800 : #endif /* READ_QUANTIZE */
801 :
802 : #ifdef PNG_READ_GAMMA_SUPPORTED
803 : void PNGFAPI
804 23 : png_set_gamma_fixed(png_structrp png_ptr, png_fixed_point scrn_gamma,
805 : png_fixed_point file_gamma)
806 : {
807 : png_debug(1, "in png_set_gamma_fixed");
808 :
809 23 : if (png_rtran_ok(png_ptr, 0) == 0)
810 0 : return;
811 :
812 : /* New in libpng-1.5.4 - reserve particular negative values as flags. */
813 23 : scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/);
814 23 : file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/);
815 :
816 : /* Checking the gamma values for being >0 was added in 1.5.4 along with the
817 : * premultiplied alpha support; this actually hides an undocumented feature
818 : * of the previous implementation which allowed gamma processing to be
819 : * disabled in background handling. There is no evidence (so far) that this
820 : * was being used; however, png_set_background itself accepted and must still
821 : * accept '0' for the gamma value it takes, because it isn't always used.
822 : *
823 : * Since this is an API change (albeit a very minor one that removes an
824 : * undocumented API feature) the following checks were only enabled in
825 : * libpng-1.6.0.
826 : */
827 23 : if (file_gamma <= 0)
828 0 : png_error(png_ptr, "invalid file gamma in png_set_gamma");
829 :
830 23 : if (scrn_gamma <= 0)
831 0 : png_error(png_ptr, "invalid screen gamma in png_set_gamma");
832 :
833 : /* Set the gamma values unconditionally - this overrides the value in the PNG
834 : * file if a gAMA chunk was present. png_set_alpha_mode provides a
835 : * different, easier, way to default the file gamma.
836 : */
837 23 : png_ptr->colorspace.gamma = file_gamma;
838 23 : png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
839 23 : png_ptr->screen_gamma = scrn_gamma;
840 : }
841 :
842 : # ifdef PNG_FLOATING_POINT_SUPPORTED
843 : void PNGAPI
844 23 : png_set_gamma(png_structrp png_ptr, double scrn_gamma, double file_gamma)
845 : {
846 23 : png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma),
847 : convert_gamma_value(png_ptr, file_gamma));
848 23 : }
849 : # endif /* FLOATING_POINT */
850 : #endif /* READ_GAMMA */
851 :
852 : #ifdef PNG_READ_EXPAND_SUPPORTED
853 : /* Expand paletted images to RGB, expand grayscale images of
854 : * less than 8-bit depth to 8-bit depth, and expand tRNS chunks
855 : * to alpha channels.
856 : */
857 : void PNGAPI
858 4 : png_set_expand(png_structrp png_ptr)
859 : {
860 : png_debug(1, "in png_set_expand");
861 :
862 4 : if (png_rtran_ok(png_ptr, 0) == 0)
863 0 : return;
864 :
865 4 : png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
866 : }
867 :
868 : /* GRR 19990627: the following three functions currently are identical
869 : * to png_set_expand(). However, it is entirely reasonable that someone
870 : * might wish to expand an indexed image to RGB but *not* expand a single,
871 : * fully transparent palette entry to a full alpha channel--perhaps instead
872 : * convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
873 : * the transparent color with a particular RGB value, or drop tRNS entirely.
874 : * IOW, a future version of the library may make the transformations flag
875 : * a bit more fine-grained, with separate bits for each of these three
876 : * functions.
877 : *
878 : * More to the point, these functions make it obvious what libpng will be
879 : * doing, whereas "expand" can (and does) mean any number of things.
880 : *
881 : * GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified
882 : * to expand only the sample depth but not to expand the tRNS to alpha
883 : * and its name was changed to png_set_expand_gray_1_2_4_to_8().
884 : */
885 :
886 : /* Expand paletted images to RGB. */
887 : void PNGAPI
888 0 : png_set_palette_to_rgb(png_structrp png_ptr)
889 : {
890 : png_debug(1, "in png_set_palette_to_rgb");
891 :
892 0 : if (png_rtran_ok(png_ptr, 0) == 0)
893 0 : return;
894 :
895 0 : png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
896 : }
897 :
898 : /* Expand grayscale images of less than 8-bit depth to 8 bits. */
899 : void PNGAPI
900 31 : png_set_expand_gray_1_2_4_to_8(png_structrp png_ptr)
901 : {
902 : png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
903 :
904 31 : if (png_rtran_ok(png_ptr, 0) == 0)
905 0 : return;
906 :
907 31 : png_ptr->transformations |= PNG_EXPAND;
908 : }
909 :
910 : /* Expand tRNS chunks to alpha channels. */
911 : void PNGAPI
912 0 : png_set_tRNS_to_alpha(png_structrp png_ptr)
913 : {
914 : png_debug(1, "in png_set_tRNS_to_alpha");
915 :
916 0 : if (png_rtran_ok(png_ptr, 0) == 0)
917 0 : return;
918 :
919 0 : png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
920 : }
921 : #endif /* READ_EXPAND */
922 :
923 : #ifdef PNG_READ_EXPAND_16_SUPPORTED
924 : /* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise
925 : * it may not work correctly.)
926 : */
927 : void PNGAPI
928 : png_set_expand_16(png_structrp png_ptr)
929 : {
930 : png_debug(1, "in png_set_expand_16");
931 :
932 : if (png_rtran_ok(png_ptr, 0) == 0)
933 : return;
934 :
935 : png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
936 : }
937 : #endif
938 :
939 : #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
940 : void PNGAPI
941 31 : png_set_gray_to_rgb(png_structrp png_ptr)
942 : {
943 : png_debug(1, "in png_set_gray_to_rgb");
944 :
945 31 : if (png_rtran_ok(png_ptr, 0) == 0)
946 0 : return;
947 :
948 : /* Because rgb must be 8 bits or more: */
949 31 : png_set_expand_gray_1_2_4_to_8(png_ptr);
950 31 : png_ptr->transformations |= PNG_GRAY_TO_RGB;
951 : }
952 : #endif
953 :
954 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
955 : void PNGFAPI
956 : png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,
957 : png_fixed_point red, png_fixed_point green)
958 : {
959 : png_debug(1, "in png_set_rgb_to_gray");
960 :
961 : /* Need the IHDR here because of the check on color_type below. */
962 : /* TODO: fix this */
963 : if (png_rtran_ok(png_ptr, 1) == 0)
964 : return;
965 :
966 : switch (error_action)
967 : {
968 : case PNG_ERROR_ACTION_NONE:
969 : png_ptr->transformations |= PNG_RGB_TO_GRAY;
970 : break;
971 :
972 : case PNG_ERROR_ACTION_WARN:
973 : png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
974 : break;
975 :
976 : case PNG_ERROR_ACTION_ERROR:
977 : png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
978 : break;
979 :
980 : default:
981 : png_error(png_ptr, "invalid error action to rgb_to_gray");
982 : }
983 :
984 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
985 : #ifdef PNG_READ_EXPAND_SUPPORTED
986 : png_ptr->transformations |= PNG_EXPAND;
987 : #else
988 : {
989 : /* Make this an error in 1.6 because otherwise the application may assume
990 : * that it just worked and get a memory overwrite.
991 : */
992 : png_error(png_ptr,
993 : "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED");
994 :
995 : /* png_ptr->transformations &= ~PNG_RGB_TO_GRAY; */
996 : }
997 : #endif
998 : {
999 : if (red >= 0 && green >= 0 && red + green <= PNG_FP_1)
1000 : {
1001 : png_uint_16 red_int, green_int;
1002 :
1003 : /* NOTE: this calculation does not round, but this behavior is retained
1004 : * for consistency; the inaccuracy is very small. The code here always
1005 : * overwrites the coefficients, regardless of whether they have been
1006 : * defaulted or set already.
1007 : */
1008 : red_int = (png_uint_16)(((png_uint_32)red*32768)/100000);
1009 : green_int = (png_uint_16)(((png_uint_32)green*32768)/100000);
1010 :
1011 : png_ptr->rgb_to_gray_red_coeff = red_int;
1012 : png_ptr->rgb_to_gray_green_coeff = green_int;
1013 : png_ptr->rgb_to_gray_coefficients_set = 1;
1014 : }
1015 :
1016 : else
1017 : {
1018 : if (red >= 0 && green >= 0)
1019 : png_app_warning(png_ptr,
1020 : "ignoring out of range rgb_to_gray coefficients");
1021 :
1022 : /* Use the defaults, from the cHRM chunk if set, else the historical
1023 : * values which are close to the sRGB/HDTV/ITU-Rec 709 values. See
1024 : * png_do_rgb_to_gray for more discussion of the values. In this case
1025 : * the coefficients are not marked as 'set' and are not overwritten if
1026 : * something has already provided a default.
1027 : */
1028 : if (png_ptr->rgb_to_gray_red_coeff == 0 &&
1029 : png_ptr->rgb_to_gray_green_coeff == 0)
1030 : {
1031 : png_ptr->rgb_to_gray_red_coeff = 6968;
1032 : png_ptr->rgb_to_gray_green_coeff = 23434;
1033 : /* png_ptr->rgb_to_gray_blue_coeff = 2366; */
1034 : }
1035 : }
1036 : }
1037 : }
1038 :
1039 : #ifdef PNG_FLOATING_POINT_SUPPORTED
1040 : /* Convert a RGB image to a grayscale of the same width. This allows us,
1041 : * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
1042 : */
1043 :
1044 : void PNGAPI
1045 : png_set_rgb_to_gray(png_structrp png_ptr, int error_action, double red,
1046 : double green)
1047 : {
1048 : png_set_rgb_to_gray_fixed(png_ptr, error_action,
1049 : png_fixed(png_ptr, red, "rgb to gray red coefficient"),
1050 : png_fixed(png_ptr, green, "rgb to gray green coefficient"));
1051 : }
1052 : #endif /* FLOATING POINT */
1053 :
1054 : #endif /* RGB_TO_GRAY */
1055 :
1056 : #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
1057 : defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
1058 : void PNGAPI
1059 : png_set_read_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
1060 : read_user_transform_fn)
1061 : {
1062 : png_debug(1, "in png_set_read_user_transform_fn");
1063 :
1064 : #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
1065 : png_ptr->transformations |= PNG_USER_TRANSFORM;
1066 : png_ptr->read_user_transform_fn = read_user_transform_fn;
1067 : #endif
1068 : }
1069 : #endif
1070 :
1071 : #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1072 : #ifdef PNG_READ_GAMMA_SUPPORTED
1073 : /* In the case of gamma transformations only do transformations on images where
1074 : * the [file] gamma and screen_gamma are not close reciprocals, otherwise it
1075 : * slows things down slightly, and also needlessly introduces small errors.
1076 : */
1077 : static int /* PRIVATE */
1078 23 : png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma)
1079 : {
1080 : /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
1081 : * correction as a difference of the overall transform from 1.0
1082 : *
1083 : * We want to compare the threshold with s*f - 1, if we get
1084 : * overflow here it is because of wacky gamma values so we
1085 : * turn on processing anyway.
1086 : */
1087 : png_fixed_point gtest;
1088 46 : return !png_muldiv(>est, screen_gamma, file_gamma, PNG_FP_1) ||
1089 23 : png_gamma_significant(gtest);
1090 : }
1091 : #endif
1092 :
1093 : /* Initialize everything needed for the read. This includes modifying
1094 : * the palette.
1095 : */
1096 :
1097 : /* For the moment 'png_init_palette_transformations' and
1098 : * 'png_init_rgb_transformations' only do some flag canceling optimizations.
1099 : * The intent is that these two routines should have palette or rgb operations
1100 : * extracted from 'png_init_read_transformations'.
1101 : */
1102 : static void /* PRIVATE */
1103 2 : png_init_palette_transformations(png_structrp png_ptr)
1104 : {
1105 : /* Called to handle the (input) palette case. In png_do_read_transformations
1106 : * the first step is to expand the palette if requested, so this code must
1107 : * take care to only make changes that are invariant with respect to the
1108 : * palette expansion, or only do them if there is no expansion.
1109 : *
1110 : * STRIP_ALPHA has already been handled in the caller (by setting num_trans
1111 : * to 0.)
1112 : */
1113 2 : int input_has_alpha = 0;
1114 2 : int input_has_transparency = 0;
1115 :
1116 2 : if (png_ptr->num_trans > 0)
1117 : {
1118 : int i;
1119 :
1120 : /* Ignore if all the entries are opaque (unlikely!) */
1121 4 : for (i=0; i<png_ptr->num_trans; ++i)
1122 : {
1123 2 : if (png_ptr->trans_alpha[i] == 255)
1124 0 : continue;
1125 2 : else if (png_ptr->trans_alpha[i] == 0)
1126 2 : input_has_transparency = 1;
1127 : else
1128 : {
1129 0 : input_has_transparency = 1;
1130 0 : input_has_alpha = 1;
1131 0 : break;
1132 : }
1133 : }
1134 : }
1135 :
1136 : /* If no alpha we can optimize. */
1137 2 : if (input_has_alpha == 0)
1138 : {
1139 : /* Any alpha means background and associative alpha processing is
1140 : * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA
1141 : * and ENCODE_ALPHA are irrelevant.
1142 : */
1143 2 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
1144 2 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
1145 :
1146 2 : if (input_has_transparency == 0)
1147 0 : png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
1148 : }
1149 :
1150 : #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
1151 : /* png_set_background handling - deals with the complexity of whether the
1152 : * background color is in the file format or the screen format in the case
1153 : * where an 'expand' will happen.
1154 : */
1155 :
1156 : /* The following code cannot be entered in the alpha pre-multiplication case
1157 : * because PNG_BACKGROUND_EXPAND is cancelled below.
1158 : */
1159 : if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
1160 : (png_ptr->transformations & PNG_EXPAND) != 0)
1161 : {
1162 : {
1163 : png_ptr->background.red =
1164 : png_ptr->palette[png_ptr->background.index].red;
1165 : png_ptr->background.green =
1166 : png_ptr->palette[png_ptr->background.index].green;
1167 : png_ptr->background.blue =
1168 : png_ptr->palette[png_ptr->background.index].blue;
1169 :
1170 : #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
1171 : if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
1172 : {
1173 : if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
1174 : {
1175 : /* Invert the alpha channel (in tRNS) unless the pixels are
1176 : * going to be expanded, in which case leave it for later
1177 : */
1178 : int i, istop = png_ptr->num_trans;
1179 :
1180 : for (i=0; i<istop; i++)
1181 : png_ptr->trans_alpha[i] = (png_byte)(255 -
1182 : png_ptr->trans_alpha[i]);
1183 : }
1184 : }
1185 : #endif /* READ_INVERT_ALPHA */
1186 : }
1187 : } /* background expand and (therefore) no alpha association. */
1188 : #endif /* READ_EXPAND && READ_BACKGROUND */
1189 2 : }
1190 :
1191 : static void /* PRIVATE */
1192 29 : png_init_rgb_transformations(png_structrp png_ptr)
1193 : {
1194 : /* Added to libpng-1.5.4: check the color type to determine whether there
1195 : * is any alpha or transparency in the image and simply cancel the
1196 : * background and alpha mode stuff if there isn't.
1197 : */
1198 29 : int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0;
1199 29 : int input_has_transparency = png_ptr->num_trans > 0;
1200 :
1201 : /* If no alpha we can optimize. */
1202 29 : if (input_has_alpha == 0)
1203 : {
1204 : /* Any alpha means background and associative alpha processing is
1205 : * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA
1206 : * and ENCODE_ALPHA are irrelevant.
1207 : */
1208 : # ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1209 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
1210 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
1211 : # endif
1212 :
1213 0 : if (input_has_transparency == 0)
1214 0 : png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
1215 : }
1216 :
1217 : #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
1218 : /* png_set_background handling - deals with the complexity of whether the
1219 : * background color is in the file format or the screen format in the case
1220 : * where an 'expand' will happen.
1221 : */
1222 :
1223 : /* The following code cannot be entered in the alpha pre-multiplication case
1224 : * because PNG_BACKGROUND_EXPAND is cancelled below.
1225 : */
1226 : if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
1227 : (png_ptr->transformations & PNG_EXPAND) != 0 &&
1228 : (png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
1229 : /* i.e., GRAY or GRAY_ALPHA */
1230 : {
1231 : {
1232 : /* Expand background and tRNS chunks */
1233 : int gray = png_ptr->background.gray;
1234 : int trans_gray = png_ptr->trans_color.gray;
1235 :
1236 : switch (png_ptr->bit_depth)
1237 : {
1238 : case 1:
1239 : gray *= 0xff;
1240 : trans_gray *= 0xff;
1241 : break;
1242 :
1243 : case 2:
1244 : gray *= 0x55;
1245 : trans_gray *= 0x55;
1246 : break;
1247 :
1248 : case 4:
1249 : gray *= 0x11;
1250 : trans_gray *= 0x11;
1251 : break;
1252 :
1253 : default:
1254 :
1255 : case 8:
1256 : /* FALL THROUGH (Already 8 bits) */
1257 :
1258 : case 16:
1259 : /* Already a full 16 bits */
1260 : break;
1261 : }
1262 :
1263 : png_ptr->background.red = png_ptr->background.green =
1264 : png_ptr->background.blue = (png_uint_16)gray;
1265 :
1266 : if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
1267 : {
1268 : png_ptr->trans_color.red = png_ptr->trans_color.green =
1269 : png_ptr->trans_color.blue = (png_uint_16)trans_gray;
1270 : }
1271 : }
1272 : } /* background expand and (therefore) no alpha association. */
1273 : #endif /* READ_EXPAND && READ_BACKGROUND */
1274 29 : }
1275 :
1276 : void /* PRIVATE */
1277 31 : png_init_read_transformations(png_structrp png_ptr)
1278 : {
1279 : png_debug(1, "in png_init_read_transformations");
1280 :
1281 : /* This internal function is called from png_read_start_row in pngrutil.c
1282 : * and it is called before the 'rowbytes' calculation is done, so the code
1283 : * in here can change or update the transformations flags.
1284 : *
1285 : * First do updates that do not depend on the details of the PNG image data
1286 : * being processed.
1287 : */
1288 :
1289 : #ifdef PNG_READ_GAMMA_SUPPORTED
1290 : /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds
1291 : * png_set_alpha_mode and this is another source for a default file gamma so
1292 : * the test needs to be performed later - here. In addition prior to 1.5.4
1293 : * the tests were repeated for the PALETTE color type here - this is no
1294 : * longer necessary (and doesn't seem to have been necessary before.)
1295 : */
1296 : {
1297 : /* The following temporary indicates if overall gamma correction is
1298 : * required.
1299 : */
1300 31 : int gamma_correction = 0;
1301 :
1302 31 : if (png_ptr->colorspace.gamma != 0) /* has been set */
1303 : {
1304 31 : if (png_ptr->screen_gamma != 0) /* screen set too */
1305 23 : gamma_correction = png_gamma_threshold(png_ptr->colorspace.gamma,
1306 : png_ptr->screen_gamma);
1307 :
1308 : else
1309 : /* Assume the output matches the input; a long time default behavior
1310 : * of libpng, although the standard has nothing to say about this.
1311 : */
1312 8 : png_ptr->screen_gamma = png_reciprocal(png_ptr->colorspace.gamma);
1313 : }
1314 :
1315 0 : else if (png_ptr->screen_gamma != 0)
1316 : /* The converse - assume the file matches the screen, note that this
1317 : * perhaps undesireable default can (from 1.5.4) be changed by calling
1318 : * png_set_alpha_mode (even if the alpha handling mode isn't required
1319 : * or isn't changed from the default.)
1320 : */
1321 0 : png_ptr->colorspace.gamma = png_reciprocal(png_ptr->screen_gamma);
1322 :
1323 : else /* neither are set */
1324 : /* Just in case the following prevents any processing - file and screen
1325 : * are both assumed to be linear and there is no way to introduce a
1326 : * third gamma value other than png_set_background with 'UNIQUE', and,
1327 : * prior to 1.5.4
1328 : */
1329 0 : png_ptr->screen_gamma = png_ptr->colorspace.gamma = PNG_FP_1;
1330 :
1331 : /* We have a gamma value now. */
1332 31 : png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
1333 :
1334 : /* Now turn the gamma transformation on or off as appropriate. Notice
1335 : * that PNG_GAMMA just refers to the file->screen correction. Alpha
1336 : * composition may independently cause gamma correction because it needs
1337 : * linear data (e.g. if the file has a gAMA chunk but the screen gamma
1338 : * hasn't been specified.) In any case this flag may get turned off in
1339 : * the code immediately below if the transform can be handled outside the
1340 : * row loop.
1341 : */
1342 31 : if (gamma_correction != 0)
1343 0 : png_ptr->transformations |= PNG_GAMMA;
1344 :
1345 : else
1346 31 : png_ptr->transformations &= ~PNG_GAMMA;
1347 : }
1348 : #endif
1349 :
1350 : /* Certain transformations have the effect of preventing other
1351 : * transformations that happen afterward in png_do_read_transformations;
1352 : * resolve the interdependencies here. From the code of
1353 : * png_do_read_transformations the order is:
1354 : *
1355 : * 1) PNG_EXPAND (including PNG_EXPAND_tRNS)
1356 : * 2) PNG_STRIP_ALPHA (if no compose)
1357 : * 3) PNG_RGB_TO_GRAY
1358 : * 4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY
1359 : * 5) PNG_COMPOSE
1360 : * 6) PNG_GAMMA
1361 : * 7) PNG_STRIP_ALPHA (if compose)
1362 : * 8) PNG_ENCODE_ALPHA
1363 : * 9) PNG_SCALE_16_TO_8
1364 : * 10) PNG_16_TO_8
1365 : * 11) PNG_QUANTIZE (converts to palette)
1366 : * 12) PNG_EXPAND_16
1367 : * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY
1368 : * 14) PNG_INVERT_MONO
1369 : * 15) PNG_INVERT_ALPHA
1370 : * 16) PNG_SHIFT
1371 : * 17) PNG_PACK
1372 : * 18) PNG_BGR
1373 : * 19) PNG_PACKSWAP
1374 : * 20) PNG_FILLER (includes PNG_ADD_ALPHA)
1375 : * 21) PNG_SWAP_ALPHA
1376 : * 22) PNG_SWAP_BYTES
1377 : * 23) PNG_USER_TRANSFORM [must be last]
1378 : */
1379 : #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
1380 : if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
1381 : (png_ptr->transformations & PNG_COMPOSE) == 0)
1382 : {
1383 : /* Stripping the alpha channel happens immediately after the 'expand'
1384 : * transformations, before all other transformation, so it cancels out
1385 : * the alpha handling. It has the side effect negating the effect of
1386 : * PNG_EXPAND_tRNS too:
1387 : */
1388 : png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA |
1389 : PNG_EXPAND_tRNS);
1390 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
1391 :
1392 : /* Kill the tRNS chunk itself too. Prior to 1.5.4 this did not happen
1393 : * so transparency information would remain just so long as it wasn't
1394 : * expanded. This produces unexpected API changes if the set of things
1395 : * that do PNG_EXPAND_tRNS changes (perfectly possible given the
1396 : * documentation - which says ask for what you want, accept what you
1397 : * get.) This makes the behavior consistent from 1.5.4:
1398 : */
1399 : png_ptr->num_trans = 0;
1400 : }
1401 : #endif /* STRIP_ALPHA supported, no COMPOSE */
1402 :
1403 : #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
1404 : /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
1405 : * settings will have no effect.
1406 : */
1407 : if (png_gamma_significant(png_ptr->screen_gamma) == 0)
1408 : {
1409 : png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
1410 : png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
1411 : }
1412 : #endif
1413 :
1414 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1415 : /* Make sure the coefficients for the rgb to gray conversion are set
1416 : * appropriately.
1417 : */
1418 : if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
1419 : png_colorspace_set_rgb_coefficients(png_ptr);
1420 : #endif
1421 :
1422 : #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
1423 : #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
1424 : /* Detect gray background and attempt to enable optimization for
1425 : * gray --> RGB case.
1426 : *
1427 : * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
1428 : * RGB_ALPHA (in which case need_expand is superfluous anyway), the
1429 : * background color might actually be gray yet not be flagged as such.
1430 : * This is not a problem for the current code, which uses
1431 : * PNG_BACKGROUND_IS_GRAY only to decide when to do the
1432 : * png_do_gray_to_rgb() transformation.
1433 : *
1434 : * TODO: this code needs to be revised to avoid the complexity and
1435 : * interdependencies. The color type of the background should be recorded in
1436 : * png_set_background, along with the bit depth, then the code has a record
1437 : * of exactly what color space the background is currently in.
1438 : */
1439 : if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0)
1440 : {
1441 : /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
1442 : * the file was grayscale the background value is gray.
1443 : */
1444 : if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
1445 : png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
1446 : }
1447 :
1448 : else if ((png_ptr->transformations & PNG_COMPOSE) != 0)
1449 : {
1450 : /* PNG_COMPOSE: png_set_background was called with need_expand false,
1451 : * so the color is in the color space of the output or png_set_alpha_mode
1452 : * was called and the color is black. Ignore RGB_TO_GRAY because that
1453 : * happens before GRAY_TO_RGB.
1454 : */
1455 : if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
1456 : {
1457 : if (png_ptr->background.red == png_ptr->background.green &&
1458 : png_ptr->background.red == png_ptr->background.blue)
1459 : {
1460 : png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
1461 : png_ptr->background.gray = png_ptr->background.red;
1462 : }
1463 : }
1464 : }
1465 : #endif /* READ_EXPAND && READ_BACKGROUND */
1466 : #endif /* READ_GRAY_TO_RGB */
1467 :
1468 : /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations
1469 : * can be performed directly on the palette, and some (such as rgb to gray)
1470 : * can be optimized inside the palette. This is particularly true of the
1471 : * composite (background and alpha) stuff, which can be pretty much all done
1472 : * in the palette even if the result is expanded to RGB or gray afterward.
1473 : *
1474 : * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and
1475 : * earlier and the palette stuff is actually handled on the first row. This
1476 : * leads to the reported bug that the palette returned by png_get_PLTE is not
1477 : * updated.
1478 : */
1479 31 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1480 2 : png_init_palette_transformations(png_ptr);
1481 :
1482 : else
1483 29 : png_init_rgb_transformations(png_ptr);
1484 :
1485 : #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
1486 : defined(PNG_READ_EXPAND_16_SUPPORTED)
1487 : if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
1488 : (png_ptr->transformations & PNG_COMPOSE) != 0 &&
1489 : (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
1490 : png_ptr->bit_depth != 16)
1491 : {
1492 : /* TODO: fix this. Because the expand_16 operation is after the compose
1493 : * handling the background color must be 8, not 16, bits deep, but the
1494 : * application will supply a 16-bit value so reduce it here.
1495 : *
1496 : * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at
1497 : * present, so that case is ok (until do_expand_16 is moved.)
1498 : *
1499 : * NOTE: this discards the low 16 bits of the user supplied background
1500 : * color, but until expand_16 works properly there is no choice!
1501 : */
1502 : # define CHOP(x) (x)=((png_uint_16)PNG_DIV257(x))
1503 : CHOP(png_ptr->background.red);
1504 : CHOP(png_ptr->background.green);
1505 : CHOP(png_ptr->background.blue);
1506 : CHOP(png_ptr->background.gray);
1507 : # undef CHOP
1508 : }
1509 : #endif /* READ_BACKGROUND && READ_EXPAND_16 */
1510 :
1511 : #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
1512 : (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
1513 : defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
1514 : if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) != 0 &&
1515 : (png_ptr->transformations & PNG_COMPOSE) != 0 &&
1516 : (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
1517 : png_ptr->bit_depth == 16)
1518 : {
1519 : /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
1520 : * component this will also happen after PNG_COMPOSE and so the background
1521 : * color must be pre-expanded here.
1522 : *
1523 : * TODO: fix this too.
1524 : */
1525 : png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257);
1526 : png_ptr->background.green =
1527 : (png_uint_16)(png_ptr->background.green * 257);
1528 : png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257);
1529 : png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257);
1530 : }
1531 : #endif
1532 :
1533 : /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the
1534 : * background support (see the comments in scripts/pnglibconf.dfa), this
1535 : * allows pre-multiplication of the alpha channel to be implemented as
1536 : * compositing on black. This is probably sub-optimal and has been done in
1537 : * 1.5.4 betas simply to enable external critique and testing (i.e. to
1538 : * implement the new API quickly, without lots of internal changes.)
1539 : */
1540 :
1541 : #ifdef PNG_READ_GAMMA_SUPPORTED
1542 : # ifdef PNG_READ_BACKGROUND_SUPPORTED
1543 : /* Includes ALPHA_MODE */
1544 : png_ptr->background_1 = png_ptr->background;
1545 : # endif
1546 :
1547 : /* This needs to change - in the palette image case a whole set of tables are
1548 : * built when it would be quicker to just calculate the correct value for
1549 : * each palette entry directly. Also, the test is too tricky - why check
1550 : * PNG_RGB_TO_GRAY if PNG_GAMMA is not set? The answer seems to be that
1551 : * PNG_GAMMA is cancelled even if the gamma is known? The test excludes the
1552 : * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction
1553 : * the gamma tables will not be built even if composition is required on a
1554 : * gamma encoded value.
1555 : *
1556 : * In 1.5.4 this is addressed below by an additional check on the individual
1557 : * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
1558 : * tables.
1559 : */
1560 62 : if ((png_ptr->transformations & PNG_GAMMA) != 0 ||
1561 31 : ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0 &&
1562 0 : (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
1563 31 : png_gamma_significant(png_ptr->screen_gamma) != 0)) ||
1564 31 : ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
1565 0 : (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
1566 0 : png_gamma_significant(png_ptr->screen_gamma) != 0
1567 : # ifdef PNG_READ_BACKGROUND_SUPPORTED
1568 : || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE &&
1569 : png_gamma_significant(png_ptr->background_gamma) != 0)
1570 : # endif
1571 31 : )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
1572 0 : png_gamma_significant(png_ptr->screen_gamma) != 0))
1573 : {
1574 0 : png_build_gamma_table(png_ptr, png_ptr->bit_depth);
1575 :
1576 : #ifdef PNG_READ_BACKGROUND_SUPPORTED
1577 : if ((png_ptr->transformations & PNG_COMPOSE) != 0)
1578 : {
1579 : /* Issue a warning about this combination: because RGB_TO_GRAY is
1580 : * optimized to do the gamma transform if present yet do_background has
1581 : * to do the same thing if both options are set a
1582 : * double-gamma-correction happens. This is true in all versions of
1583 : * libpng to date.
1584 : */
1585 : if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
1586 : png_warning(png_ptr,
1587 : "libpng does not support gamma+background+rgb_to_gray");
1588 :
1589 : if ((png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) != 0)
1590 : {
1591 : /* We don't get to here unless there is a tRNS chunk with non-opaque
1592 : * entries - see the checking code at the start of this function.
1593 : */
1594 : png_color back, back_1;
1595 : png_colorp palette = png_ptr->palette;
1596 : int num_palette = png_ptr->num_palette;
1597 : int i;
1598 : if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
1599 : {
1600 :
1601 : back.red = png_ptr->gamma_table[png_ptr->background.red];
1602 : back.green = png_ptr->gamma_table[png_ptr->background.green];
1603 : back.blue = png_ptr->gamma_table[png_ptr->background.blue];
1604 :
1605 : back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
1606 : back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
1607 : back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
1608 : }
1609 : else
1610 : {
1611 : png_fixed_point g, gs;
1612 :
1613 : switch (png_ptr->background_gamma_type)
1614 : {
1615 : case PNG_BACKGROUND_GAMMA_SCREEN:
1616 : g = (png_ptr->screen_gamma);
1617 : gs = PNG_FP_1;
1618 : break;
1619 :
1620 : case PNG_BACKGROUND_GAMMA_FILE:
1621 : g = png_reciprocal(png_ptr->colorspace.gamma);
1622 : gs = png_reciprocal2(png_ptr->colorspace.gamma,
1623 : png_ptr->screen_gamma);
1624 : break;
1625 :
1626 : case PNG_BACKGROUND_GAMMA_UNIQUE:
1627 : g = png_reciprocal(png_ptr->background_gamma);
1628 : gs = png_reciprocal2(png_ptr->background_gamma,
1629 : png_ptr->screen_gamma);
1630 : break;
1631 : default:
1632 : g = PNG_FP_1; /* back_1 */
1633 : gs = PNG_FP_1; /* back */
1634 : break;
1635 : }
1636 :
1637 : if (png_gamma_significant(gs) != 0)
1638 : {
1639 : back.red = png_gamma_8bit_correct(png_ptr->background.red,
1640 : gs);
1641 : back.green = png_gamma_8bit_correct(png_ptr->background.green,
1642 : gs);
1643 : back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
1644 : gs);
1645 : }
1646 :
1647 : else
1648 : {
1649 : back.red = (png_byte)png_ptr->background.red;
1650 : back.green = (png_byte)png_ptr->background.green;
1651 : back.blue = (png_byte)png_ptr->background.blue;
1652 : }
1653 :
1654 : if (png_gamma_significant(g) != 0)
1655 : {
1656 : back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
1657 : g);
1658 : back_1.green = png_gamma_8bit_correct(
1659 : png_ptr->background.green, g);
1660 : back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
1661 : g);
1662 : }
1663 :
1664 : else
1665 : {
1666 : back_1.red = (png_byte)png_ptr->background.red;
1667 : back_1.green = (png_byte)png_ptr->background.green;
1668 : back_1.blue = (png_byte)png_ptr->background.blue;
1669 : }
1670 : }
1671 :
1672 : for (i = 0; i < num_palette; i++)
1673 : {
1674 : if (i < (int)png_ptr->num_trans &&
1675 : png_ptr->trans_alpha[i] != 0xff)
1676 : {
1677 : if (png_ptr->trans_alpha[i] == 0)
1678 : {
1679 : palette[i] = back;
1680 : }
1681 : else /* if (png_ptr->trans_alpha[i] != 0xff) */
1682 : {
1683 : png_byte v, w;
1684 :
1685 : v = png_ptr->gamma_to_1[palette[i].red];
1686 : png_composite(w, v, png_ptr->trans_alpha[i], back_1.red);
1687 : palette[i].red = png_ptr->gamma_from_1[w];
1688 :
1689 : v = png_ptr->gamma_to_1[palette[i].green];
1690 : png_composite(w, v, png_ptr->trans_alpha[i], back_1.green);
1691 : palette[i].green = png_ptr->gamma_from_1[w];
1692 :
1693 : v = png_ptr->gamma_to_1[palette[i].blue];
1694 : png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue);
1695 : palette[i].blue = png_ptr->gamma_from_1[w];
1696 : }
1697 : }
1698 : else
1699 : {
1700 : palette[i].red = png_ptr->gamma_table[palette[i].red];
1701 : palette[i].green = png_ptr->gamma_table[palette[i].green];
1702 : palette[i].blue = png_ptr->gamma_table[palette[i].blue];
1703 : }
1704 : }
1705 :
1706 : /* Prevent the transformations being done again.
1707 : *
1708 : * NOTE: this is highly dubious; it removes the transformations in
1709 : * place. This seems inconsistent with the general treatment of the
1710 : * transformations elsewhere.
1711 : */
1712 : png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA);
1713 : } /* color_type == PNG_COLOR_TYPE_PALETTE */
1714 :
1715 : /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
1716 : else /* color_type != PNG_COLOR_TYPE_PALETTE */
1717 : {
1718 : int gs_sig, g_sig;
1719 : png_fixed_point g = PNG_FP_1; /* Correction to linear */
1720 : png_fixed_point gs = PNG_FP_1; /* Correction to screen */
1721 :
1722 : switch (png_ptr->background_gamma_type)
1723 : {
1724 : case PNG_BACKGROUND_GAMMA_SCREEN:
1725 : g = png_ptr->screen_gamma;
1726 : /* gs = PNG_FP_1; */
1727 : break;
1728 :
1729 : case PNG_BACKGROUND_GAMMA_FILE:
1730 : g = png_reciprocal(png_ptr->colorspace.gamma);
1731 : gs = png_reciprocal2(png_ptr->colorspace.gamma,
1732 : png_ptr->screen_gamma);
1733 : break;
1734 :
1735 : case PNG_BACKGROUND_GAMMA_UNIQUE:
1736 : g = png_reciprocal(png_ptr->background_gamma);
1737 : gs = png_reciprocal2(png_ptr->background_gamma,
1738 : png_ptr->screen_gamma);
1739 : break;
1740 :
1741 : default:
1742 : png_error(png_ptr, "invalid background gamma type");
1743 : }
1744 :
1745 : g_sig = png_gamma_significant(g);
1746 : gs_sig = png_gamma_significant(gs);
1747 :
1748 : if (g_sig != 0)
1749 : png_ptr->background_1.gray = png_gamma_correct(png_ptr,
1750 : png_ptr->background.gray, g);
1751 :
1752 : if (gs_sig != 0)
1753 : png_ptr->background.gray = png_gamma_correct(png_ptr,
1754 : png_ptr->background.gray, gs);
1755 :
1756 : if ((png_ptr->background.red != png_ptr->background.green) ||
1757 : (png_ptr->background.red != png_ptr->background.blue) ||
1758 : (png_ptr->background.red != png_ptr->background.gray))
1759 : {
1760 : /* RGB or RGBA with color background */
1761 : if (g_sig != 0)
1762 : {
1763 : png_ptr->background_1.red = png_gamma_correct(png_ptr,
1764 : png_ptr->background.red, g);
1765 :
1766 : png_ptr->background_1.green = png_gamma_correct(png_ptr,
1767 : png_ptr->background.green, g);
1768 :
1769 : png_ptr->background_1.blue = png_gamma_correct(png_ptr,
1770 : png_ptr->background.blue, g);
1771 : }
1772 :
1773 : if (gs_sig != 0)
1774 : {
1775 : png_ptr->background.red = png_gamma_correct(png_ptr,
1776 : png_ptr->background.red, gs);
1777 :
1778 : png_ptr->background.green = png_gamma_correct(png_ptr,
1779 : png_ptr->background.green, gs);
1780 :
1781 : png_ptr->background.blue = png_gamma_correct(png_ptr,
1782 : png_ptr->background.blue, gs);
1783 : }
1784 : }
1785 :
1786 : else
1787 : {
1788 : /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
1789 : png_ptr->background_1.red = png_ptr->background_1.green
1790 : = png_ptr->background_1.blue = png_ptr->background_1.gray;
1791 :
1792 : png_ptr->background.red = png_ptr->background.green
1793 : = png_ptr->background.blue = png_ptr->background.gray;
1794 : }
1795 :
1796 : /* The background is now in screen gamma: */
1797 : png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN;
1798 : } /* color_type != PNG_COLOR_TYPE_PALETTE */
1799 : }/* png_ptr->transformations & PNG_BACKGROUND */
1800 :
1801 : else
1802 : /* Transformation does not include PNG_BACKGROUND */
1803 : #endif /* READ_BACKGROUND */
1804 0 : if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
1805 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
1806 : /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
1807 : && ((png_ptr->transformations & PNG_EXPAND) == 0 ||
1808 : (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
1809 : #endif
1810 : )
1811 : {
1812 0 : png_colorp palette = png_ptr->palette;
1813 0 : int num_palette = png_ptr->num_palette;
1814 : int i;
1815 :
1816 : /* NOTE: there are other transformations that should probably be in
1817 : * here too.
1818 : */
1819 0 : for (i = 0; i < num_palette; i++)
1820 : {
1821 0 : palette[i].red = png_ptr->gamma_table[palette[i].red];
1822 0 : palette[i].green = png_ptr->gamma_table[palette[i].green];
1823 0 : palette[i].blue = png_ptr->gamma_table[palette[i].blue];
1824 : }
1825 :
1826 : /* Done the gamma correction. */
1827 0 : png_ptr->transformations &= ~PNG_GAMMA;
1828 : } /* color_type == PALETTE && !PNG_BACKGROUND transformation */
1829 : }
1830 : #ifdef PNG_READ_BACKGROUND_SUPPORTED
1831 : else
1832 : #endif
1833 : #endif /* READ_GAMMA */
1834 :
1835 : #ifdef PNG_READ_BACKGROUND_SUPPORTED
1836 : /* No GAMMA transformation (see the hanging else 4 lines above) */
1837 : if ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
1838 : (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
1839 : {
1840 : int i;
1841 : int istop = (int)png_ptr->num_trans;
1842 : png_color back;
1843 : png_colorp palette = png_ptr->palette;
1844 :
1845 : back.red = (png_byte)png_ptr->background.red;
1846 : back.green = (png_byte)png_ptr->background.green;
1847 : back.blue = (png_byte)png_ptr->background.blue;
1848 :
1849 : for (i = 0; i < istop; i++)
1850 : {
1851 : if (png_ptr->trans_alpha[i] == 0)
1852 : {
1853 : palette[i] = back;
1854 : }
1855 :
1856 : else if (png_ptr->trans_alpha[i] != 0xff)
1857 : {
1858 : /* The png_composite() macro is defined in png.h */
1859 : png_composite(palette[i].red, palette[i].red,
1860 : png_ptr->trans_alpha[i], back.red);
1861 :
1862 : png_composite(palette[i].green, palette[i].green,
1863 : png_ptr->trans_alpha[i], back.green);
1864 :
1865 : png_composite(palette[i].blue, palette[i].blue,
1866 : png_ptr->trans_alpha[i], back.blue);
1867 : }
1868 : }
1869 :
1870 : png_ptr->transformations &= ~PNG_COMPOSE;
1871 : }
1872 : #endif /* READ_BACKGROUND */
1873 :
1874 : #ifdef PNG_READ_SHIFT_SUPPORTED
1875 : if ((png_ptr->transformations & PNG_SHIFT) != 0 &&
1876 : (png_ptr->transformations & PNG_EXPAND) == 0 &&
1877 : (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
1878 : {
1879 : int i;
1880 : int istop = png_ptr->num_palette;
1881 : int shift = 8 - png_ptr->sig_bit.red;
1882 :
1883 : png_ptr->transformations &= ~PNG_SHIFT;
1884 :
1885 : /* significant bits can be in the range 1 to 7 for a meaninful result, if
1886 : * the number of significant bits is 0 then no shift is done (this is an
1887 : * error condition which is silently ignored.)
1888 : */
1889 : if (shift > 0 && shift < 8)
1890 : for (i=0; i<istop; ++i)
1891 : {
1892 : int component = png_ptr->palette[i].red;
1893 :
1894 : component >>= shift;
1895 : png_ptr->palette[i].red = (png_byte)component;
1896 : }
1897 :
1898 : shift = 8 - png_ptr->sig_bit.green;
1899 : if (shift > 0 && shift < 8)
1900 : for (i=0; i<istop; ++i)
1901 : {
1902 : int component = png_ptr->palette[i].green;
1903 :
1904 : component >>= shift;
1905 : png_ptr->palette[i].green = (png_byte)component;
1906 : }
1907 :
1908 : shift = 8 - png_ptr->sig_bit.blue;
1909 : if (shift > 0 && shift < 8)
1910 : for (i=0; i<istop; ++i)
1911 : {
1912 : int component = png_ptr->palette[i].blue;
1913 :
1914 : component >>= shift;
1915 : png_ptr->palette[i].blue = (png_byte)component;
1916 : }
1917 : }
1918 : #endif /* READ_SHIFT */
1919 31 : }
1920 :
1921 : /* Modify the info structure to reflect the transformations. The
1922 : * info should be updated so a PNG file could be written with it,
1923 : * assuming the transformations result in valid PNG data.
1924 : */
1925 : void /* PRIVATE */
1926 31 : png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
1927 : {
1928 : png_debug(1, "in png_read_transform_info");
1929 :
1930 : #ifdef PNG_READ_EXPAND_SUPPORTED
1931 31 : if ((png_ptr->transformations & PNG_EXPAND) != 0)
1932 : {
1933 31 : if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
1934 : {
1935 : /* This check must match what actually happens in
1936 : * png_do_expand_palette; if it ever checks the tRNS chunk to see if
1937 : * it is all opaque we must do the same (at present it does not.)
1938 : */
1939 2 : if (png_ptr->num_trans > 0)
1940 2 : info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
1941 :
1942 : else
1943 0 : info_ptr->color_type = PNG_COLOR_TYPE_RGB;
1944 :
1945 2 : info_ptr->bit_depth = 8;
1946 2 : info_ptr->num_trans = 0;
1947 :
1948 2 : if (png_ptr->palette == NULL)
1949 0 : png_error (png_ptr, "Palette is NULL in indexed image");
1950 : }
1951 : else
1952 : {
1953 29 : if (png_ptr->num_trans != 0)
1954 : {
1955 0 : if ((png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
1956 0 : info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
1957 : }
1958 29 : if (info_ptr->bit_depth < 8)
1959 0 : info_ptr->bit_depth = 8;
1960 :
1961 29 : info_ptr->num_trans = 0;
1962 : }
1963 : }
1964 : #endif
1965 :
1966 : #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
1967 : defined(PNG_READ_ALPHA_MODE_SUPPORTED)
1968 : /* The following is almost certainly wrong unless the background value is in
1969 : * the screen space!
1970 : */
1971 : if ((png_ptr->transformations & PNG_COMPOSE) != 0)
1972 : info_ptr->background = png_ptr->background;
1973 : #endif
1974 :
1975 : #ifdef PNG_READ_GAMMA_SUPPORTED
1976 : /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4),
1977 : * however it seems that the code in png_init_read_transformations, which has
1978 : * been called before this from png_read_update_info->png_read_start_row
1979 : * sometimes does the gamma transform and cancels the flag.
1980 : *
1981 : * TODO: this looks wrong; the info_ptr should end up with a gamma equal to
1982 : * the screen_gamma value. The following probably results in weirdness if
1983 : * the info_ptr is used by the app after the rows have been read.
1984 : */
1985 31 : info_ptr->colorspace.gamma = png_ptr->colorspace.gamma;
1986 : #endif
1987 :
1988 31 : if (info_ptr->bit_depth == 16)
1989 : {
1990 : # ifdef PNG_READ_16BIT_SUPPORTED
1991 : # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
1992 0 : if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
1993 0 : info_ptr->bit_depth = 8;
1994 : # endif
1995 :
1996 : # ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
1997 : if ((png_ptr->transformations & PNG_16_TO_8) != 0)
1998 : info_ptr->bit_depth = 8;
1999 : # endif
2000 :
2001 : # else
2002 : /* No 16-bit support: force chopping 16-bit input down to 8, in this case
2003 : * the app program can chose if both APIs are available by setting the
2004 : * correct scaling to use.
2005 : */
2006 : # ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
2007 : /* For compatibility with previous versions use the strip method by
2008 : * default. This code works because if PNG_SCALE_16_TO_8 is already
2009 : * set the code below will do that in preference to the chop.
2010 : */
2011 : png_ptr->transformations |= PNG_16_TO_8;
2012 : info_ptr->bit_depth = 8;
2013 : # else
2014 :
2015 : # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
2016 : png_ptr->transformations |= PNG_SCALE_16_TO_8;
2017 : info_ptr->bit_depth = 8;
2018 : # else
2019 :
2020 : CONFIGURATION ERROR: you must enable at least one 16 to 8 method
2021 : # endif
2022 : # endif
2023 : #endif /* !READ_16BIT */
2024 : }
2025 :
2026 : #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
2027 31 : if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
2028 31 : info_ptr->color_type = (png_byte)(info_ptr->color_type |
2029 : PNG_COLOR_MASK_COLOR);
2030 : #endif
2031 :
2032 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2033 : if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
2034 : info_ptr->color_type = (png_byte)(info_ptr->color_type &
2035 : ~PNG_COLOR_MASK_COLOR);
2036 : #endif
2037 :
2038 : #ifdef PNG_READ_QUANTIZE_SUPPORTED
2039 : if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
2040 : {
2041 : if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
2042 : (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
2043 : png_ptr->palette_lookup != 0 && info_ptr->bit_depth == 8)
2044 : {
2045 : info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
2046 : }
2047 : }
2048 : #endif
2049 :
2050 : #ifdef PNG_READ_EXPAND_16_SUPPORTED
2051 : if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
2052 : info_ptr->bit_depth == 8 &&
2053 : info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
2054 : {
2055 : info_ptr->bit_depth = 16;
2056 : }
2057 : #endif
2058 :
2059 : #ifdef PNG_READ_PACK_SUPPORTED
2060 : if ((png_ptr->transformations & PNG_PACK) != 0 &&
2061 : (info_ptr->bit_depth < 8))
2062 : info_ptr->bit_depth = 8;
2063 : #endif
2064 :
2065 31 : if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
2066 0 : info_ptr->channels = 1;
2067 :
2068 31 : else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
2069 31 : info_ptr->channels = 3;
2070 :
2071 : else
2072 0 : info_ptr->channels = 1;
2073 :
2074 : #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
2075 : if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0)
2076 : {
2077 : info_ptr->color_type = (png_byte)(info_ptr->color_type &
2078 : ~PNG_COLOR_MASK_ALPHA);
2079 : info_ptr->num_trans = 0;
2080 : }
2081 : #endif
2082 :
2083 31 : if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
2084 31 : info_ptr->channels++;
2085 :
2086 : #ifdef PNG_READ_FILLER_SUPPORTED
2087 : /* STRIP_ALPHA and FILLER allowed: MASK_ALPHA bit stripped above */
2088 : if ((png_ptr->transformations & PNG_FILLER) != 0 &&
2089 : (info_ptr->color_type == PNG_COLOR_TYPE_RGB ||
2090 : info_ptr->color_type == PNG_COLOR_TYPE_GRAY))
2091 : {
2092 : info_ptr->channels++;
2093 : /* If adding a true alpha channel not just filler */
2094 : if ((png_ptr->transformations & PNG_ADD_ALPHA) != 0)
2095 : info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
2096 : }
2097 : #endif
2098 :
2099 : #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
2100 : defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
2101 : if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
2102 : {
2103 : if (png_ptr->user_transform_depth != 0)
2104 : info_ptr->bit_depth = png_ptr->user_transform_depth;
2105 :
2106 : if (png_ptr->user_transform_channels != 0)
2107 : info_ptr->channels = png_ptr->user_transform_channels;
2108 : }
2109 : #endif
2110 :
2111 62 : info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
2112 31 : info_ptr->bit_depth);
2113 :
2114 31 : info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
2115 :
2116 : /* Adding in 1.5.4: cache the above value in png_struct so that we can later
2117 : * check in png_rowbytes that the user buffer won't get overwritten. Note
2118 : * that the field is not always set - if png_read_update_info isn't called
2119 : * the application has to either not do any transforms or get the calculation
2120 : * right itself.
2121 : */
2122 31 : png_ptr->info_rowbytes = info_ptr->rowbytes;
2123 :
2124 : #ifndef PNG_READ_EXPAND_SUPPORTED
2125 : if (png_ptr != NULL)
2126 : return;
2127 : #endif
2128 31 : }
2129 :
2130 : #ifdef PNG_READ_PACK_SUPPORTED
2131 : /* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
2132 : * without changing the actual values. Thus, if you had a row with
2133 : * a bit depth of 1, you would end up with bytes that only contained
2134 : * the numbers 0 or 1. If you would rather they contain 0 and 255, use
2135 : * png_do_shift() after this.
2136 : */
2137 : static void
2138 : png_do_unpack(png_row_infop row_info, png_bytep row)
2139 : {
2140 : png_debug(1, "in png_do_unpack");
2141 :
2142 : if (row_info->bit_depth < 8)
2143 : {
2144 : png_uint_32 i;
2145 : png_uint_32 row_width=row_info->width;
2146 :
2147 : switch (row_info->bit_depth)
2148 : {
2149 : case 1:
2150 : {
2151 : png_bytep sp = row + (png_size_t)((row_width - 1) >> 3);
2152 : png_bytep dp = row + (png_size_t)row_width - 1;
2153 : png_uint_32 shift = 7U - ((row_width + 7U) & 0x07);
2154 : for (i = 0; i < row_width; i++)
2155 : {
2156 : *dp = (png_byte)((*sp >> shift) & 0x01);
2157 :
2158 : if (shift == 7)
2159 : {
2160 : shift = 0;
2161 : sp--;
2162 : }
2163 :
2164 : else
2165 : shift++;
2166 :
2167 : dp--;
2168 : }
2169 : break;
2170 : }
2171 :
2172 : case 2:
2173 : {
2174 :
2175 : png_bytep sp = row + (png_size_t)((row_width - 1) >> 2);
2176 : png_bytep dp = row + (png_size_t)row_width - 1;
2177 : png_uint_32 shift = ((3U - ((row_width + 3U) & 0x03)) << 1);
2178 : for (i = 0; i < row_width; i++)
2179 : {
2180 : *dp = (png_byte)((*sp >> shift) & 0x03);
2181 :
2182 : if (shift == 6)
2183 : {
2184 : shift = 0;
2185 : sp--;
2186 : }
2187 :
2188 : else
2189 : shift += 2;
2190 :
2191 : dp--;
2192 : }
2193 : break;
2194 : }
2195 :
2196 : case 4:
2197 : {
2198 : png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
2199 : png_bytep dp = row + (png_size_t)row_width - 1;
2200 : png_uint_32 shift = ((1U - ((row_width + 1U) & 0x01)) << 2);
2201 : for (i = 0; i < row_width; i++)
2202 : {
2203 : *dp = (png_byte)((*sp >> shift) & 0x0f);
2204 :
2205 : if (shift == 4)
2206 : {
2207 : shift = 0;
2208 : sp--;
2209 : }
2210 :
2211 : else
2212 : shift = 4;
2213 :
2214 : dp--;
2215 : }
2216 : break;
2217 : }
2218 :
2219 : default:
2220 : break;
2221 : }
2222 : row_info->bit_depth = 8;
2223 : row_info->pixel_depth = (png_byte)(8 * row_info->channels);
2224 : row_info->rowbytes = row_width * row_info->channels;
2225 : }
2226 : }
2227 : #endif
2228 :
2229 : #ifdef PNG_READ_SHIFT_SUPPORTED
2230 : /* Reverse the effects of png_do_shift. This routine merely shifts the
2231 : * pixels back to their significant bits values. Thus, if you have
2232 : * a row of bit depth 8, but only 5 are significant, this will shift
2233 : * the values back to 0 through 31.
2234 : */
2235 : static void
2236 : png_do_unshift(png_row_infop row_info, png_bytep row,
2237 : png_const_color_8p sig_bits)
2238 : {
2239 : int color_type;
2240 :
2241 : png_debug(1, "in png_do_unshift");
2242 :
2243 : /* The palette case has already been handled in the _init routine. */
2244 : color_type = row_info->color_type;
2245 :
2246 : if (color_type != PNG_COLOR_TYPE_PALETTE)
2247 : {
2248 : int shift[4];
2249 : int channels = 0;
2250 : int bit_depth = row_info->bit_depth;
2251 :
2252 : if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
2253 : {
2254 : shift[channels++] = bit_depth - sig_bits->red;
2255 : shift[channels++] = bit_depth - sig_bits->green;
2256 : shift[channels++] = bit_depth - sig_bits->blue;
2257 : }
2258 :
2259 : else
2260 : {
2261 : shift[channels++] = bit_depth - sig_bits->gray;
2262 : }
2263 :
2264 : if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
2265 : {
2266 : shift[channels++] = bit_depth - sig_bits->alpha;
2267 : }
2268 :
2269 : {
2270 : int c, have_shift;
2271 :
2272 : for (c = have_shift = 0; c < channels; ++c)
2273 : {
2274 : /* A shift of more than the bit depth is an error condition but it
2275 : * gets ignored here.
2276 : */
2277 : if (shift[c] <= 0 || shift[c] >= bit_depth)
2278 : shift[c] = 0;
2279 :
2280 : else
2281 : have_shift = 1;
2282 : }
2283 :
2284 : if (have_shift == 0)
2285 : return;
2286 : }
2287 :
2288 : switch (bit_depth)
2289 : {
2290 : default:
2291 : /* Must be 1bpp gray: should not be here! */
2292 : /* NOTREACHED */
2293 : break;
2294 :
2295 : case 2:
2296 : /* Must be 2bpp gray */
2297 : /* assert(channels == 1 && shift[0] == 1) */
2298 : {
2299 : png_bytep bp = row;
2300 : png_bytep bp_end = bp + row_info->rowbytes;
2301 :
2302 : while (bp < bp_end)
2303 : {
2304 : int b = (*bp >> 1) & 0x55;
2305 : *bp++ = (png_byte)b;
2306 : }
2307 : break;
2308 : }
2309 :
2310 : case 4:
2311 : /* Must be 4bpp gray */
2312 : /* assert(channels == 1) */
2313 : {
2314 : png_bytep bp = row;
2315 : png_bytep bp_end = bp + row_info->rowbytes;
2316 : int gray_shift = shift[0];
2317 : int mask = 0xf >> gray_shift;
2318 :
2319 : mask |= mask << 4;
2320 :
2321 : while (bp < bp_end)
2322 : {
2323 : int b = (*bp >> gray_shift) & mask;
2324 : *bp++ = (png_byte)b;
2325 : }
2326 : break;
2327 : }
2328 :
2329 : case 8:
2330 : /* Single byte components, G, GA, RGB, RGBA */
2331 : {
2332 : png_bytep bp = row;
2333 : png_bytep bp_end = bp + row_info->rowbytes;
2334 : int channel = 0;
2335 :
2336 : while (bp < bp_end)
2337 : {
2338 : int b = *bp >> shift[channel];
2339 : if (++channel >= channels)
2340 : channel = 0;
2341 : *bp++ = (png_byte)b;
2342 : }
2343 : break;
2344 : }
2345 :
2346 : #ifdef PNG_READ_16BIT_SUPPORTED
2347 : case 16:
2348 : /* Double byte components, G, GA, RGB, RGBA */
2349 : {
2350 : png_bytep bp = row;
2351 : png_bytep bp_end = bp + row_info->rowbytes;
2352 : int channel = 0;
2353 :
2354 : while (bp < bp_end)
2355 : {
2356 : int value = (bp[0] << 8) + bp[1];
2357 :
2358 : value >>= shift[channel];
2359 : if (++channel >= channels)
2360 : channel = 0;
2361 : *bp++ = (png_byte)(value >> 8);
2362 : *bp++ = (png_byte)value;
2363 : }
2364 : break;
2365 : }
2366 : #endif
2367 : }
2368 : }
2369 : }
2370 : #endif
2371 :
2372 : #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
2373 : /* Scale rows of bit depth 16 down to 8 accurately */
2374 : static void
2375 0 : png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
2376 : {
2377 : png_debug(1, "in png_do_scale_16_to_8");
2378 :
2379 0 : if (row_info->bit_depth == 16)
2380 : {
2381 0 : png_bytep sp = row; /* source */
2382 0 : png_bytep dp = row; /* destination */
2383 0 : png_bytep ep = sp + row_info->rowbytes; /* end+1 */
2384 :
2385 0 : while (sp < ep)
2386 : {
2387 : /* The input is an array of 16-bit components, these must be scaled to
2388 : * 8 bits each. For a 16-bit value V the required value (from the PNG
2389 : * specification) is:
2390 : *
2391 : * (V * 255) / 65535
2392 : *
2393 : * This reduces to round(V / 257), or floor((V + 128.5)/257)
2394 : *
2395 : * Represent V as the two byte value vhi.vlo. Make a guess that the
2396 : * result is the top byte of V, vhi, then the correction to this value
2397 : * is:
2398 : *
2399 : * error = floor(((V-vhi.vhi) + 128.5) / 257)
2400 : * = floor(((vlo-vhi) + 128.5) / 257)
2401 : *
2402 : * This can be approximated using integer arithmetic (and a signed
2403 : * shift):
2404 : *
2405 : * error = (vlo-vhi+128) >> 8;
2406 : *
2407 : * The approximate differs from the exact answer only when (vlo-vhi) is
2408 : * 128; it then gives a correction of +1 when the exact correction is
2409 : * 0. This gives 128 errors. The exact answer (correct for all 16-bit
2410 : * input values) is:
2411 : *
2412 : * error = (vlo-vhi+128)*65535 >> 24;
2413 : *
2414 : * An alternative arithmetic calculation which also gives no errors is:
2415 : *
2416 : * (V * 255 + 32895) >> 16
2417 : */
2418 :
2419 0 : png_int_32 tmp = *sp++; /* must be signed! */
2420 0 : tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24;
2421 0 : *dp++ = (png_byte)tmp;
2422 : }
2423 :
2424 0 : row_info->bit_depth = 8;
2425 0 : row_info->pixel_depth = (png_byte)(8 * row_info->channels);
2426 0 : row_info->rowbytes = row_info->width * row_info->channels;
2427 : }
2428 0 : }
2429 : #endif
2430 :
2431 : #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
2432 : static void
2433 : /* Simply discard the low byte. This was the default behavior prior
2434 : * to libpng-1.5.4.
2435 : */
2436 : png_do_chop(png_row_infop row_info, png_bytep row)
2437 : {
2438 : png_debug(1, "in png_do_chop");
2439 :
2440 : if (row_info->bit_depth == 16)
2441 : {
2442 : png_bytep sp = row; /* source */
2443 : png_bytep dp = row; /* destination */
2444 : png_bytep ep = sp + row_info->rowbytes; /* end+1 */
2445 :
2446 : while (sp < ep)
2447 : {
2448 : *dp++ = *sp;
2449 : sp += 2; /* skip low byte */
2450 : }
2451 :
2452 : row_info->bit_depth = 8;
2453 : row_info->pixel_depth = (png_byte)(8 * row_info->channels);
2454 : row_info->rowbytes = row_info->width * row_info->channels;
2455 : }
2456 : }
2457 : #endif
2458 :
2459 : #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
2460 : static void
2461 : png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
2462 : {
2463 : png_debug(1, "in png_do_read_swap_alpha");
2464 :
2465 : {
2466 : png_uint_32 row_width = row_info->width;
2467 : if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
2468 : {
2469 : /* This converts from RGBA to ARGB */
2470 : if (row_info->bit_depth == 8)
2471 : {
2472 : png_bytep sp = row + row_info->rowbytes;
2473 : png_bytep dp = sp;
2474 : png_byte save;
2475 : png_uint_32 i;
2476 :
2477 : for (i = 0; i < row_width; i++)
2478 : {
2479 : save = *(--sp);
2480 : *(--dp) = *(--sp);
2481 : *(--dp) = *(--sp);
2482 : *(--dp) = *(--sp);
2483 : *(--dp) = save;
2484 : }
2485 : }
2486 :
2487 : #ifdef PNG_READ_16BIT_SUPPORTED
2488 : /* This converts from RRGGBBAA to AARRGGBB */
2489 : else
2490 : {
2491 : png_bytep sp = row + row_info->rowbytes;
2492 : png_bytep dp = sp;
2493 : png_byte save[2];
2494 : png_uint_32 i;
2495 :
2496 : for (i = 0; i < row_width; i++)
2497 : {
2498 : save[0] = *(--sp);
2499 : save[1] = *(--sp);
2500 : *(--dp) = *(--sp);
2501 : *(--dp) = *(--sp);
2502 : *(--dp) = *(--sp);
2503 : *(--dp) = *(--sp);
2504 : *(--dp) = *(--sp);
2505 : *(--dp) = *(--sp);
2506 : *(--dp) = save[0];
2507 : *(--dp) = save[1];
2508 : }
2509 : }
2510 : #endif
2511 : }
2512 :
2513 : else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
2514 : {
2515 : /* This converts from GA to AG */
2516 : if (row_info->bit_depth == 8)
2517 : {
2518 : png_bytep sp = row + row_info->rowbytes;
2519 : png_bytep dp = sp;
2520 : png_byte save;
2521 : png_uint_32 i;
2522 :
2523 : for (i = 0; i < row_width; i++)
2524 : {
2525 : save = *(--sp);
2526 : *(--dp) = *(--sp);
2527 : *(--dp) = save;
2528 : }
2529 : }
2530 :
2531 : #ifdef PNG_READ_16BIT_SUPPORTED
2532 : /* This converts from GGAA to AAGG */
2533 : else
2534 : {
2535 : png_bytep sp = row + row_info->rowbytes;
2536 : png_bytep dp = sp;
2537 : png_byte save[2];
2538 : png_uint_32 i;
2539 :
2540 : for (i = 0; i < row_width; i++)
2541 : {
2542 : save[0] = *(--sp);
2543 : save[1] = *(--sp);
2544 : *(--dp) = *(--sp);
2545 : *(--dp) = *(--sp);
2546 : *(--dp) = save[0];
2547 : *(--dp) = save[1];
2548 : }
2549 : }
2550 : #endif
2551 : }
2552 : }
2553 : }
2554 : #endif
2555 :
2556 : #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
2557 : static void
2558 : png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
2559 : {
2560 : png_uint_32 row_width;
2561 : png_debug(1, "in png_do_read_invert_alpha");
2562 :
2563 : row_width = row_info->width;
2564 : if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
2565 : {
2566 : if (row_info->bit_depth == 8)
2567 : {
2568 : /* This inverts the alpha channel in RGBA */
2569 : png_bytep sp = row + row_info->rowbytes;
2570 : png_bytep dp = sp;
2571 : png_uint_32 i;
2572 :
2573 : for (i = 0; i < row_width; i++)
2574 : {
2575 : *(--dp) = (png_byte)(255 - *(--sp));
2576 :
2577 : /* This does nothing:
2578 : *(--dp) = *(--sp);
2579 : *(--dp) = *(--sp);
2580 : *(--dp) = *(--sp);
2581 : We can replace it with:
2582 : */
2583 : sp-=3;
2584 : dp=sp;
2585 : }
2586 : }
2587 :
2588 : #ifdef PNG_READ_16BIT_SUPPORTED
2589 : /* This inverts the alpha channel in RRGGBBAA */
2590 : else
2591 : {
2592 : png_bytep sp = row + row_info->rowbytes;
2593 : png_bytep dp = sp;
2594 : png_uint_32 i;
2595 :
2596 : for (i = 0; i < row_width; i++)
2597 : {
2598 : *(--dp) = (png_byte)(255 - *(--sp));
2599 : *(--dp) = (png_byte)(255 - *(--sp));
2600 :
2601 : /* This does nothing:
2602 : *(--dp) = *(--sp);
2603 : *(--dp) = *(--sp);
2604 : *(--dp) = *(--sp);
2605 : *(--dp) = *(--sp);
2606 : *(--dp) = *(--sp);
2607 : *(--dp) = *(--sp);
2608 : We can replace it with:
2609 : */
2610 : sp-=6;
2611 : dp=sp;
2612 : }
2613 : }
2614 : #endif
2615 : }
2616 : else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
2617 : {
2618 : if (row_info->bit_depth == 8)
2619 : {
2620 : /* This inverts the alpha channel in GA */
2621 : png_bytep sp = row + row_info->rowbytes;
2622 : png_bytep dp = sp;
2623 : png_uint_32 i;
2624 :
2625 : for (i = 0; i < row_width; i++)
2626 : {
2627 : *(--dp) = (png_byte)(255 - *(--sp));
2628 : *(--dp) = *(--sp);
2629 : }
2630 : }
2631 :
2632 : #ifdef PNG_READ_16BIT_SUPPORTED
2633 : else
2634 : {
2635 : /* This inverts the alpha channel in GGAA */
2636 : png_bytep sp = row + row_info->rowbytes;
2637 : png_bytep dp = sp;
2638 : png_uint_32 i;
2639 :
2640 : for (i = 0; i < row_width; i++)
2641 : {
2642 : *(--dp) = (png_byte)(255 - *(--sp));
2643 : *(--dp) = (png_byte)(255 - *(--sp));
2644 : /*
2645 : *(--dp) = *(--sp);
2646 : *(--dp) = *(--sp);
2647 : */
2648 : sp-=2;
2649 : dp=sp;
2650 : }
2651 : }
2652 : #endif
2653 : }
2654 : }
2655 : #endif
2656 :
2657 : #ifdef PNG_READ_FILLER_SUPPORTED
2658 : /* Add filler channel if we have RGB color */
2659 : static void
2660 : png_do_read_filler(png_row_infop row_info, png_bytep row,
2661 : png_uint_32 filler, png_uint_32 flags)
2662 : {
2663 : png_uint_32 i;
2664 : png_uint_32 row_width = row_info->width;
2665 :
2666 : #ifdef PNG_READ_16BIT_SUPPORTED
2667 : png_byte hi_filler = (png_byte)(filler>>8);
2668 : #endif
2669 : png_byte lo_filler = (png_byte)filler;
2670 :
2671 : png_debug(1, "in png_do_read_filler");
2672 :
2673 : if (
2674 : row_info->color_type == PNG_COLOR_TYPE_GRAY)
2675 : {
2676 : if (row_info->bit_depth == 8)
2677 : {
2678 : if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
2679 : {
2680 : /* This changes the data from G to GX */
2681 : png_bytep sp = row + (png_size_t)row_width;
2682 : png_bytep dp = sp + (png_size_t)row_width;
2683 : for (i = 1; i < row_width; i++)
2684 : {
2685 : *(--dp) = lo_filler;
2686 : *(--dp) = *(--sp);
2687 : }
2688 : *(--dp) = lo_filler;
2689 : row_info->channels = 2;
2690 : row_info->pixel_depth = 16;
2691 : row_info->rowbytes = row_width * 2;
2692 : }
2693 :
2694 : else
2695 : {
2696 : /* This changes the data from G to XG */
2697 : png_bytep sp = row + (png_size_t)row_width;
2698 : png_bytep dp = sp + (png_size_t)row_width;
2699 : for (i = 0; i < row_width; i++)
2700 : {
2701 : *(--dp) = *(--sp);
2702 : *(--dp) = lo_filler;
2703 : }
2704 : row_info->channels = 2;
2705 : row_info->pixel_depth = 16;
2706 : row_info->rowbytes = row_width * 2;
2707 : }
2708 : }
2709 :
2710 : #ifdef PNG_READ_16BIT_SUPPORTED
2711 : else if (row_info->bit_depth == 16)
2712 : {
2713 : if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
2714 : {
2715 : /* This changes the data from GG to GGXX */
2716 : png_bytep sp = row + (png_size_t)row_width * 2;
2717 : png_bytep dp = sp + (png_size_t)row_width * 2;
2718 : for (i = 1; i < row_width; i++)
2719 : {
2720 : *(--dp) = lo_filler;
2721 : *(--dp) = hi_filler;
2722 : *(--dp) = *(--sp);
2723 : *(--dp) = *(--sp);
2724 : }
2725 : *(--dp) = lo_filler;
2726 : *(--dp) = hi_filler;
2727 : row_info->channels = 2;
2728 : row_info->pixel_depth = 32;
2729 : row_info->rowbytes = row_width * 4;
2730 : }
2731 :
2732 : else
2733 : {
2734 : /* This changes the data from GG to XXGG */
2735 : png_bytep sp = row + (png_size_t)row_width * 2;
2736 : png_bytep dp = sp + (png_size_t)row_width * 2;
2737 : for (i = 0; i < row_width; i++)
2738 : {
2739 : *(--dp) = *(--sp);
2740 : *(--dp) = *(--sp);
2741 : *(--dp) = lo_filler;
2742 : *(--dp) = hi_filler;
2743 : }
2744 : row_info->channels = 2;
2745 : row_info->pixel_depth = 32;
2746 : row_info->rowbytes = row_width * 4;
2747 : }
2748 : }
2749 : #endif
2750 : } /* COLOR_TYPE == GRAY */
2751 : else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
2752 : {
2753 : if (row_info->bit_depth == 8)
2754 : {
2755 : if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
2756 : {
2757 : /* This changes the data from RGB to RGBX */
2758 : png_bytep sp = row + (png_size_t)row_width * 3;
2759 : png_bytep dp = sp + (png_size_t)row_width;
2760 : for (i = 1; i < row_width; i++)
2761 : {
2762 : *(--dp) = lo_filler;
2763 : *(--dp) = *(--sp);
2764 : *(--dp) = *(--sp);
2765 : *(--dp) = *(--sp);
2766 : }
2767 : *(--dp) = lo_filler;
2768 : row_info->channels = 4;
2769 : row_info->pixel_depth = 32;
2770 : row_info->rowbytes = row_width * 4;
2771 : }
2772 :
2773 : else
2774 : {
2775 : /* This changes the data from RGB to XRGB */
2776 : png_bytep sp = row + (png_size_t)row_width * 3;
2777 : png_bytep dp = sp + (png_size_t)row_width;
2778 : for (i = 0; i < row_width; i++)
2779 : {
2780 : *(--dp) = *(--sp);
2781 : *(--dp) = *(--sp);
2782 : *(--dp) = *(--sp);
2783 : *(--dp) = lo_filler;
2784 : }
2785 : row_info->channels = 4;
2786 : row_info->pixel_depth = 32;
2787 : row_info->rowbytes = row_width * 4;
2788 : }
2789 : }
2790 :
2791 : #ifdef PNG_READ_16BIT_SUPPORTED
2792 : else if (row_info->bit_depth == 16)
2793 : {
2794 : if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
2795 : {
2796 : /* This changes the data from RRGGBB to RRGGBBXX */
2797 : png_bytep sp = row + (png_size_t)row_width * 6;
2798 : png_bytep dp = sp + (png_size_t)row_width * 2;
2799 : for (i = 1; i < row_width; i++)
2800 : {
2801 : *(--dp) = lo_filler;
2802 : *(--dp) = hi_filler;
2803 : *(--dp) = *(--sp);
2804 : *(--dp) = *(--sp);
2805 : *(--dp) = *(--sp);
2806 : *(--dp) = *(--sp);
2807 : *(--dp) = *(--sp);
2808 : *(--dp) = *(--sp);
2809 : }
2810 : *(--dp) = lo_filler;
2811 : *(--dp) = hi_filler;
2812 : row_info->channels = 4;
2813 : row_info->pixel_depth = 64;
2814 : row_info->rowbytes = row_width * 8;
2815 : }
2816 :
2817 : else
2818 : {
2819 : /* This changes the data from RRGGBB to XXRRGGBB */
2820 : png_bytep sp = row + (png_size_t)row_width * 6;
2821 : png_bytep dp = sp + (png_size_t)row_width * 2;
2822 : for (i = 0; i < row_width; i++)
2823 : {
2824 : *(--dp) = *(--sp);
2825 : *(--dp) = *(--sp);
2826 : *(--dp) = *(--sp);
2827 : *(--dp) = *(--sp);
2828 : *(--dp) = *(--sp);
2829 : *(--dp) = *(--sp);
2830 : *(--dp) = lo_filler;
2831 : *(--dp) = hi_filler;
2832 : }
2833 :
2834 : row_info->channels = 4;
2835 : row_info->pixel_depth = 64;
2836 : row_info->rowbytes = row_width * 8;
2837 : }
2838 : }
2839 : #endif
2840 : } /* COLOR_TYPE == RGB */
2841 : }
2842 : #endif
2843 :
2844 : #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
2845 : /* Expand grayscale files to RGB, with or without alpha */
2846 : static void
2847 1538 : png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
2848 : {
2849 : png_uint_32 i;
2850 1538 : png_uint_32 row_width = row_info->width;
2851 :
2852 : png_debug(1, "in png_do_gray_to_rgb");
2853 :
2854 3076 : if (row_info->bit_depth >= 8 &&
2855 1538 : (row_info->color_type & PNG_COLOR_MASK_COLOR) == 0)
2856 : {
2857 40 : if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
2858 : {
2859 0 : if (row_info->bit_depth == 8)
2860 : {
2861 : /* This changes G to RGB */
2862 0 : png_bytep sp = row + (png_size_t)row_width - 1;
2863 0 : png_bytep dp = sp + (png_size_t)row_width * 2;
2864 0 : for (i = 0; i < row_width; i++)
2865 : {
2866 0 : *(dp--) = *sp;
2867 0 : *(dp--) = *sp;
2868 0 : *(dp--) = *(sp--);
2869 : }
2870 : }
2871 :
2872 : else
2873 : {
2874 : /* This changes GG to RRGGBB */
2875 0 : png_bytep sp = row + (png_size_t)row_width * 2 - 1;
2876 0 : png_bytep dp = sp + (png_size_t)row_width * 4;
2877 0 : for (i = 0; i < row_width; i++)
2878 : {
2879 0 : *(dp--) = *sp;
2880 0 : *(dp--) = *(sp - 1);
2881 0 : *(dp--) = *sp;
2882 0 : *(dp--) = *(sp - 1);
2883 0 : *(dp--) = *(sp--);
2884 0 : *(dp--) = *(sp--);
2885 : }
2886 : }
2887 : }
2888 :
2889 40 : else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
2890 : {
2891 40 : if (row_info->bit_depth == 8)
2892 : {
2893 : /* This changes GA to RGBA */
2894 40 : png_bytep sp = row + (png_size_t)row_width * 2 - 1;
2895 40 : png_bytep dp = sp + (png_size_t)row_width * 2;
2896 4840 : for (i = 0; i < row_width; i++)
2897 : {
2898 4800 : *(dp--) = *(sp--);
2899 4800 : *(dp--) = *sp;
2900 4800 : *(dp--) = *sp;
2901 4800 : *(dp--) = *(sp--);
2902 : }
2903 : }
2904 :
2905 : else
2906 : {
2907 : /* This changes GGAA to RRGGBBAA */
2908 0 : png_bytep sp = row + (png_size_t)row_width * 4 - 1;
2909 0 : png_bytep dp = sp + (png_size_t)row_width * 4;
2910 0 : for (i = 0; i < row_width; i++)
2911 : {
2912 0 : *(dp--) = *(sp--);
2913 0 : *(dp--) = *(sp--);
2914 0 : *(dp--) = *sp;
2915 0 : *(dp--) = *(sp - 1);
2916 0 : *(dp--) = *sp;
2917 0 : *(dp--) = *(sp - 1);
2918 0 : *(dp--) = *(sp--);
2919 0 : *(dp--) = *(sp--);
2920 : }
2921 : }
2922 : }
2923 40 : row_info->channels = (png_byte)(row_info->channels + 2);
2924 40 : row_info->color_type |= PNG_COLOR_MASK_COLOR;
2925 80 : row_info->pixel_depth = (png_byte)(row_info->channels *
2926 40 : row_info->bit_depth);
2927 40 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
2928 : }
2929 1538 : }
2930 : #endif
2931 :
2932 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2933 : /* Reduce RGB files to grayscale, with or without alpha
2934 : * using the equation given in Poynton's ColorFAQ of 1998-01-04 at
2935 : * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008 but
2936 : * versions dated 1998 through November 2002 have been archived at
2937 : * http://web.archive.org/web/20000816232553/http://www.inforamp.net/
2938 : * ~poynton/notes/colour_and_gamma/ColorFAQ.txt )
2939 : * Charles Poynton poynton at poynton.com
2940 : *
2941 : * Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
2942 : *
2943 : * which can be expressed with integers as
2944 : *
2945 : * Y = (6969 * R + 23434 * G + 2365 * B)/32768
2946 : *
2947 : * Poynton's current link (as of January 2003 through July 2011):
2948 : * <http://www.poynton.com/notes/colour_and_gamma/>
2949 : * has changed the numbers slightly:
2950 : *
2951 : * Y = 0.2126*R + 0.7152*G + 0.0722*B
2952 : *
2953 : * which can be expressed with integers as
2954 : *
2955 : * Y = (6966 * R + 23436 * G + 2366 * B)/32768
2956 : *
2957 : * Historically, however, libpng uses numbers derived from the ITU-R Rec 709
2958 : * end point chromaticities and the D65 white point. Depending on the
2959 : * precision used for the D65 white point this produces a variety of different
2960 : * numbers, however if the four decimal place value used in ITU-R Rec 709 is
2961 : * used (0.3127,0.3290) the Y calculation would be:
2962 : *
2963 : * Y = (6968 * R + 23435 * G + 2366 * B)/32768
2964 : *
2965 : * While this is correct the rounding results in an overflow for white, because
2966 : * the sum of the rounded coefficients is 32769, not 32768. Consequently
2967 : * libpng uses, instead, the closest non-overflowing approximation:
2968 : *
2969 : * Y = (6968 * R + 23434 * G + 2366 * B)/32768
2970 : *
2971 : * Starting with libpng-1.5.5, if the image being converted has a cHRM chunk
2972 : * (including an sRGB chunk) then the chromaticities are used to calculate the
2973 : * coefficients. See the chunk handling in pngrutil.c for more information.
2974 : *
2975 : * In all cases the calculation is to be done in a linear colorspace. If no
2976 : * gamma information is available to correct the encoding of the original RGB
2977 : * values this results in an implicit assumption that the original PNG RGB
2978 : * values were linear.
2979 : *
2980 : * Other integer coefficents can be used via png_set_rgb_to_gray(). Because
2981 : * the API takes just red and green coefficients the blue coefficient is
2982 : * calculated to make the sum 32768. This will result in different rounding
2983 : * to that used above.
2984 : */
2985 : static int
2986 : png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
2987 :
2988 : {
2989 : int rgb_error = 0;
2990 :
2991 : png_debug(1, "in png_do_rgb_to_gray");
2992 :
2993 : if ((row_info->color_type & PNG_COLOR_MASK_PALETTE) == 0 &&
2994 : (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
2995 : {
2996 : PNG_CONST png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
2997 : PNG_CONST png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
2998 : PNG_CONST png_uint_32 bc = 32768 - rc - gc;
2999 : PNG_CONST png_uint_32 row_width = row_info->width;
3000 : PNG_CONST int have_alpha =
3001 : (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0;
3002 :
3003 : if (row_info->bit_depth == 8)
3004 : {
3005 : #ifdef PNG_READ_GAMMA_SUPPORTED
3006 : /* Notice that gamma to/from 1 are not necessarily inverses (if
3007 : * there is an overall gamma correction). Prior to 1.5.5 this code
3008 : * checked the linearized values for equality; this doesn't match
3009 : * the documentation, the original values must be checked.
3010 : */
3011 : if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
3012 : {
3013 : png_bytep sp = row;
3014 : png_bytep dp = row;
3015 : png_uint_32 i;
3016 :
3017 : for (i = 0; i < row_width; i++)
3018 : {
3019 : png_byte red = *(sp++);
3020 : png_byte green = *(sp++);
3021 : png_byte blue = *(sp++);
3022 :
3023 : if (red != green || red != blue)
3024 : {
3025 : red = png_ptr->gamma_to_1[red];
3026 : green = png_ptr->gamma_to_1[green];
3027 : blue = png_ptr->gamma_to_1[blue];
3028 :
3029 : rgb_error |= 1;
3030 : *(dp++) = png_ptr->gamma_from_1[
3031 : (rc*red + gc*green + bc*blue + 16384)>>15];
3032 : }
3033 :
3034 : else
3035 : {
3036 : /* If there is no overall correction the table will not be
3037 : * set.
3038 : */
3039 : if (png_ptr->gamma_table != NULL)
3040 : red = png_ptr->gamma_table[red];
3041 :
3042 : *(dp++) = red;
3043 : }
3044 :
3045 : if (have_alpha != 0)
3046 : *(dp++) = *(sp++);
3047 : }
3048 : }
3049 : else
3050 : #endif
3051 : {
3052 : png_bytep sp = row;
3053 : png_bytep dp = row;
3054 : png_uint_32 i;
3055 :
3056 : for (i = 0; i < row_width; i++)
3057 : {
3058 : png_byte red = *(sp++);
3059 : png_byte green = *(sp++);
3060 : png_byte blue = *(sp++);
3061 :
3062 : if (red != green || red != blue)
3063 : {
3064 : rgb_error |= 1;
3065 : /* NOTE: this is the historical approach which simply
3066 : * truncates the results.
3067 : */
3068 : *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
3069 : }
3070 :
3071 : else
3072 : *(dp++) = red;
3073 :
3074 : if (have_alpha != 0)
3075 : *(dp++) = *(sp++);
3076 : }
3077 : }
3078 : }
3079 :
3080 : else /* RGB bit_depth == 16 */
3081 : {
3082 : #ifdef PNG_READ_GAMMA_SUPPORTED
3083 : if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL)
3084 : {
3085 : png_bytep sp = row;
3086 : png_bytep dp = row;
3087 : png_uint_32 i;
3088 :
3089 : for (i = 0; i < row_width; i++)
3090 : {
3091 : png_uint_16 red, green, blue, w;
3092 : png_byte hi,lo;
3093 :
3094 : hi=*(sp)++; lo=*(sp)++; red = (png_uint_16)((hi << 8) | (lo));
3095 : hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
3096 : hi=*(sp)++; lo=*(sp)++; blue = (png_uint_16)((hi << 8) | (lo));
3097 :
3098 : if (red == green && red == blue)
3099 : {
3100 : if (png_ptr->gamma_16_table != NULL)
3101 : w = png_ptr->gamma_16_table[(red & 0xff)
3102 : >> png_ptr->gamma_shift][red >> 8];
3103 :
3104 : else
3105 : w = red;
3106 : }
3107 :
3108 : else
3109 : {
3110 : png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red & 0xff)
3111 : >> png_ptr->gamma_shift][red>>8];
3112 : png_uint_16 green_1 =
3113 : png_ptr->gamma_16_to_1[(green & 0xff) >>
3114 : png_ptr->gamma_shift][green>>8];
3115 : png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue & 0xff)
3116 : >> png_ptr->gamma_shift][blue>>8];
3117 : png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1
3118 : + bc*blue_1 + 16384)>>15);
3119 : w = png_ptr->gamma_16_from_1[(gray16 & 0xff) >>
3120 : png_ptr->gamma_shift][gray16 >> 8];
3121 : rgb_error |= 1;
3122 : }
3123 :
3124 : *(dp++) = (png_byte)((w>>8) & 0xff);
3125 : *(dp++) = (png_byte)(w & 0xff);
3126 :
3127 : if (have_alpha != 0)
3128 : {
3129 : *(dp++) = *(sp++);
3130 : *(dp++) = *(sp++);
3131 : }
3132 : }
3133 : }
3134 : else
3135 : #endif
3136 : {
3137 : png_bytep sp = row;
3138 : png_bytep dp = row;
3139 : png_uint_32 i;
3140 :
3141 : for (i = 0; i < row_width; i++)
3142 : {
3143 : png_uint_16 red, green, blue, gray16;
3144 : png_byte hi,lo;
3145 :
3146 : hi=*(sp)++; lo=*(sp)++; red = (png_uint_16)((hi << 8) | (lo));
3147 : hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
3148 : hi=*(sp)++; lo=*(sp)++; blue = (png_uint_16)((hi << 8) | (lo));
3149 :
3150 : if (red != green || red != blue)
3151 : rgb_error |= 1;
3152 :
3153 : /* From 1.5.5 in the 16-bit case do the accurate conversion even
3154 : * in the 'fast' case - this is because this is where the code
3155 : * ends up when handling linear 16-bit data.
3156 : */
3157 : gray16 = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
3158 : 15);
3159 : *(dp++) = (png_byte)((gray16 >> 8) & 0xff);
3160 : *(dp++) = (png_byte)(gray16 & 0xff);
3161 :
3162 : if (have_alpha != 0)
3163 : {
3164 : *(dp++) = *(sp++);
3165 : *(dp++) = *(sp++);
3166 : }
3167 : }
3168 : }
3169 : }
3170 :
3171 : row_info->channels = (png_byte)(row_info->channels - 2);
3172 : row_info->color_type = (png_byte)(row_info->color_type &
3173 : ~PNG_COLOR_MASK_COLOR);
3174 : row_info->pixel_depth = (png_byte)(row_info->channels *
3175 : row_info->bit_depth);
3176 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
3177 : }
3178 : return rgb_error;
3179 : }
3180 : #endif
3181 :
3182 : #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
3183 : defined(PNG_READ_ALPHA_MODE_SUPPORTED)
3184 : /* Replace any alpha or transparency with the supplied background color.
3185 : * "background" is already in the screen gamma, while "background_1" is
3186 : * at a gamma of 1.0. Paletted files have already been taken care of.
3187 : */
3188 : static void
3189 : png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
3190 : {
3191 : #ifdef PNG_READ_GAMMA_SUPPORTED
3192 : png_const_bytep gamma_table = png_ptr->gamma_table;
3193 : png_const_bytep gamma_from_1 = png_ptr->gamma_from_1;
3194 : png_const_bytep gamma_to_1 = png_ptr->gamma_to_1;
3195 : png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table;
3196 : png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1;
3197 : png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1;
3198 : int gamma_shift = png_ptr->gamma_shift;
3199 : int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0;
3200 : #endif
3201 :
3202 : png_bytep sp;
3203 : png_uint_32 i;
3204 : png_uint_32 row_width = row_info->width;
3205 : int shift;
3206 :
3207 : png_debug(1, "in png_do_compose");
3208 :
3209 : {
3210 : switch (row_info->color_type)
3211 : {
3212 : case PNG_COLOR_TYPE_GRAY:
3213 : {
3214 : switch (row_info->bit_depth)
3215 : {
3216 : case 1:
3217 : {
3218 : sp = row;
3219 : shift = 7;
3220 : for (i = 0; i < row_width; i++)
3221 : {
3222 : if ((png_uint_16)((*sp >> shift) & 0x01)
3223 : == png_ptr->trans_color.gray)
3224 : {
3225 : unsigned int tmp = *sp & (0x7f7f >> (7 - shift));
3226 : tmp |=
3227 : (unsigned int)(png_ptr->background.gray << shift);
3228 : *sp = (png_byte)(tmp & 0xff);
3229 : }
3230 :
3231 : if (shift == 0)
3232 : {
3233 : shift = 7;
3234 : sp++;
3235 : }
3236 :
3237 : else
3238 : shift--;
3239 : }
3240 : break;
3241 : }
3242 :
3243 : case 2:
3244 : {
3245 : #ifdef PNG_READ_GAMMA_SUPPORTED
3246 : if (gamma_table != NULL)
3247 : {
3248 : sp = row;
3249 : shift = 6;
3250 : for (i = 0; i < row_width; i++)
3251 : {
3252 : if ((png_uint_16)((*sp >> shift) & 0x03)
3253 : == png_ptr->trans_color.gray)
3254 : {
3255 : unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
3256 : tmp |=
3257 : (unsigned int)png_ptr->background.gray << shift;
3258 : *sp = (png_byte)(tmp & 0xff);
3259 : }
3260 :
3261 : else
3262 : {
3263 : unsigned int p = (*sp >> shift) & 0x03;
3264 : unsigned int g = (gamma_table [p | (p << 2) |
3265 : (p << 4) | (p << 6)] >> 6) & 0x03;
3266 : unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
3267 : tmp |= (unsigned int)(g << shift);
3268 : *sp = (png_byte)(tmp & 0xff);
3269 : }
3270 :
3271 : if (shift == 0)
3272 : {
3273 : shift = 6;
3274 : sp++;
3275 : }
3276 :
3277 : else
3278 : shift -= 2;
3279 : }
3280 : }
3281 :
3282 : else
3283 : #endif
3284 : {
3285 : sp = row;
3286 : shift = 6;
3287 : for (i = 0; i < row_width; i++)
3288 : {
3289 : if ((png_uint_16)((*sp >> shift) & 0x03)
3290 : == png_ptr->trans_color.gray)
3291 : {
3292 : unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
3293 : tmp |=
3294 : (unsigned int)png_ptr->background.gray << shift;
3295 : *sp = (png_byte)(tmp & 0xff);
3296 : }
3297 :
3298 : if (shift == 0)
3299 : {
3300 : shift = 6;
3301 : sp++;
3302 : }
3303 :
3304 : else
3305 : shift -= 2;
3306 : }
3307 : }
3308 : break;
3309 : }
3310 :
3311 : case 4:
3312 : {
3313 : #ifdef PNG_READ_GAMMA_SUPPORTED
3314 : if (gamma_table != NULL)
3315 : {
3316 : sp = row;
3317 : shift = 4;
3318 : for (i = 0; i < row_width; i++)
3319 : {
3320 : if ((png_uint_16)((*sp >> shift) & 0x0f)
3321 : == png_ptr->trans_color.gray)
3322 : {
3323 : unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
3324 : tmp |=
3325 : (unsigned int)(png_ptr->background.gray << shift);
3326 : *sp = (png_byte)(tmp & 0xff);
3327 : }
3328 :
3329 : else
3330 : {
3331 : unsigned int p = (*sp >> shift) & 0x0f;
3332 : unsigned int g = (gamma_table[p | (p << 4)] >> 4) &
3333 : 0x0f;
3334 : unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
3335 : tmp |= (unsigned int)(g << shift);
3336 : *sp = (png_byte)(tmp & 0xff);
3337 : }
3338 :
3339 : if (shift == 0)
3340 : {
3341 : shift = 4;
3342 : sp++;
3343 : }
3344 :
3345 : else
3346 : shift -= 4;
3347 : }
3348 : }
3349 :
3350 : else
3351 : #endif
3352 : {
3353 : sp = row;
3354 : shift = 4;
3355 : for (i = 0; i < row_width; i++)
3356 : {
3357 : if ((png_uint_16)((*sp >> shift) & 0x0f)
3358 : == png_ptr->trans_color.gray)
3359 : {
3360 : unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
3361 : tmp |=
3362 : (unsigned int)(png_ptr->background.gray << shift);
3363 : *sp = (png_byte)(tmp & 0xff);
3364 : }
3365 :
3366 : if (shift == 0)
3367 : {
3368 : shift = 4;
3369 : sp++;
3370 : }
3371 :
3372 : else
3373 : shift -= 4;
3374 : }
3375 : }
3376 : break;
3377 : }
3378 :
3379 : case 8:
3380 : {
3381 : #ifdef PNG_READ_GAMMA_SUPPORTED
3382 : if (gamma_table != NULL)
3383 : {
3384 : sp = row;
3385 : for (i = 0; i < row_width; i++, sp++)
3386 : {
3387 : if (*sp == png_ptr->trans_color.gray)
3388 : *sp = (png_byte)png_ptr->background.gray;
3389 :
3390 : else
3391 : *sp = gamma_table[*sp];
3392 : }
3393 : }
3394 : else
3395 : #endif
3396 : {
3397 : sp = row;
3398 : for (i = 0; i < row_width; i++, sp++)
3399 : {
3400 : if (*sp == png_ptr->trans_color.gray)
3401 : *sp = (png_byte)png_ptr->background.gray;
3402 : }
3403 : }
3404 : break;
3405 : }
3406 :
3407 : case 16:
3408 : {
3409 : #ifdef PNG_READ_GAMMA_SUPPORTED
3410 : if (gamma_16 != NULL)
3411 : {
3412 : sp = row;
3413 : for (i = 0; i < row_width; i++, sp += 2)
3414 : {
3415 : png_uint_16 v;
3416 :
3417 : v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3418 :
3419 : if (v == png_ptr->trans_color.gray)
3420 : {
3421 : /* Background is already in screen gamma */
3422 : *sp = (png_byte)((png_ptr->background.gray >> 8)
3423 : & 0xff);
3424 : *(sp + 1) = (png_byte)(png_ptr->background.gray
3425 : & 0xff);
3426 : }
3427 :
3428 : else
3429 : {
3430 : v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
3431 : *sp = (png_byte)((v >> 8) & 0xff);
3432 : *(sp + 1) = (png_byte)(v & 0xff);
3433 : }
3434 : }
3435 : }
3436 : else
3437 : #endif
3438 : {
3439 : sp = row;
3440 : for (i = 0; i < row_width; i++, sp += 2)
3441 : {
3442 : png_uint_16 v;
3443 :
3444 : v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3445 :
3446 : if (v == png_ptr->trans_color.gray)
3447 : {
3448 : *sp = (png_byte)((png_ptr->background.gray >> 8)
3449 : & 0xff);
3450 : *(sp + 1) = (png_byte)(png_ptr->background.gray
3451 : & 0xff);
3452 : }
3453 : }
3454 : }
3455 : break;
3456 : }
3457 :
3458 : default:
3459 : break;
3460 : }
3461 : break;
3462 : }
3463 :
3464 : case PNG_COLOR_TYPE_RGB:
3465 : {
3466 : if (row_info->bit_depth == 8)
3467 : {
3468 : #ifdef PNG_READ_GAMMA_SUPPORTED
3469 : if (gamma_table != NULL)
3470 : {
3471 : sp = row;
3472 : for (i = 0; i < row_width; i++, sp += 3)
3473 : {
3474 : if (*sp == png_ptr->trans_color.red &&
3475 : *(sp + 1) == png_ptr->trans_color.green &&
3476 : *(sp + 2) == png_ptr->trans_color.blue)
3477 : {
3478 : *sp = (png_byte)png_ptr->background.red;
3479 : *(sp + 1) = (png_byte)png_ptr->background.green;
3480 : *(sp + 2) = (png_byte)png_ptr->background.blue;
3481 : }
3482 :
3483 : else
3484 : {
3485 : *sp = gamma_table[*sp];
3486 : *(sp + 1) = gamma_table[*(sp + 1)];
3487 : *(sp + 2) = gamma_table[*(sp + 2)];
3488 : }
3489 : }
3490 : }
3491 : else
3492 : #endif
3493 : {
3494 : sp = row;
3495 : for (i = 0; i < row_width; i++, sp += 3)
3496 : {
3497 : if (*sp == png_ptr->trans_color.red &&
3498 : *(sp + 1) == png_ptr->trans_color.green &&
3499 : *(sp + 2) == png_ptr->trans_color.blue)
3500 : {
3501 : *sp = (png_byte)png_ptr->background.red;
3502 : *(sp + 1) = (png_byte)png_ptr->background.green;
3503 : *(sp + 2) = (png_byte)png_ptr->background.blue;
3504 : }
3505 : }
3506 : }
3507 : }
3508 : else /* if (row_info->bit_depth == 16) */
3509 : {
3510 : #ifdef PNG_READ_GAMMA_SUPPORTED
3511 : if (gamma_16 != NULL)
3512 : {
3513 : sp = row;
3514 : for (i = 0; i < row_width; i++, sp += 6)
3515 : {
3516 : png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3517 :
3518 : png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
3519 : + *(sp + 3));
3520 :
3521 : png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
3522 : + *(sp + 5));
3523 :
3524 : if (r == png_ptr->trans_color.red &&
3525 : g == png_ptr->trans_color.green &&
3526 : b == png_ptr->trans_color.blue)
3527 : {
3528 : /* Background is already in screen gamma */
3529 : *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
3530 : *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
3531 : *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
3532 : & 0xff);
3533 : *(sp + 3) = (png_byte)(png_ptr->background.green
3534 : & 0xff);
3535 : *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
3536 : & 0xff);
3537 : *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
3538 : }
3539 :
3540 : else
3541 : {
3542 : png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
3543 : *sp = (png_byte)((v >> 8) & 0xff);
3544 : *(sp + 1) = (png_byte)(v & 0xff);
3545 :
3546 : v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
3547 : *(sp + 2) = (png_byte)((v >> 8) & 0xff);
3548 : *(sp + 3) = (png_byte)(v & 0xff);
3549 :
3550 : v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
3551 : *(sp + 4) = (png_byte)((v >> 8) & 0xff);
3552 : *(sp + 5) = (png_byte)(v & 0xff);
3553 : }
3554 : }
3555 : }
3556 :
3557 : else
3558 : #endif
3559 : {
3560 : sp = row;
3561 : for (i = 0; i < row_width; i++, sp += 6)
3562 : {
3563 : png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3564 :
3565 : png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
3566 : + *(sp + 3));
3567 :
3568 : png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
3569 : + *(sp + 5));
3570 :
3571 : if (r == png_ptr->trans_color.red &&
3572 : g == png_ptr->trans_color.green &&
3573 : b == png_ptr->trans_color.blue)
3574 : {
3575 : *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
3576 : *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
3577 : *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
3578 : & 0xff);
3579 : *(sp + 3) = (png_byte)(png_ptr->background.green
3580 : & 0xff);
3581 : *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
3582 : & 0xff);
3583 : *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
3584 : }
3585 : }
3586 : }
3587 : }
3588 : break;
3589 : }
3590 :
3591 : case PNG_COLOR_TYPE_GRAY_ALPHA:
3592 : {
3593 : if (row_info->bit_depth == 8)
3594 : {
3595 : #ifdef PNG_READ_GAMMA_SUPPORTED
3596 : if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
3597 : gamma_table != NULL)
3598 : {
3599 : sp = row;
3600 : for (i = 0; i < row_width; i++, sp += 2)
3601 : {
3602 : png_uint_16 a = *(sp + 1);
3603 :
3604 : if (a == 0xff)
3605 : *sp = gamma_table[*sp];
3606 :
3607 : else if (a == 0)
3608 : {
3609 : /* Background is already in screen gamma */
3610 : *sp = (png_byte)png_ptr->background.gray;
3611 : }
3612 :
3613 : else
3614 : {
3615 : png_byte v, w;
3616 :
3617 : v = gamma_to_1[*sp];
3618 : png_composite(w, v, a, png_ptr->background_1.gray);
3619 : if (optimize == 0)
3620 : w = gamma_from_1[w];
3621 : *sp = w;
3622 : }
3623 : }
3624 : }
3625 : else
3626 : #endif
3627 : {
3628 : sp = row;
3629 : for (i = 0; i < row_width; i++, sp += 2)
3630 : {
3631 : png_byte a = *(sp + 1);
3632 :
3633 : if (a == 0)
3634 : *sp = (png_byte)png_ptr->background.gray;
3635 :
3636 : else if (a < 0xff)
3637 : png_composite(*sp, *sp, a, png_ptr->background.gray);
3638 : }
3639 : }
3640 : }
3641 : else /* if (png_ptr->bit_depth == 16) */
3642 : {
3643 : #ifdef PNG_READ_GAMMA_SUPPORTED
3644 : if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
3645 : gamma_16_to_1 != NULL)
3646 : {
3647 : sp = row;
3648 : for (i = 0; i < row_width; i++, sp += 4)
3649 : {
3650 : png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
3651 : + *(sp + 3));
3652 :
3653 : if (a == (png_uint_16)0xffff)
3654 : {
3655 : png_uint_16 v;
3656 :
3657 : v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
3658 : *sp = (png_byte)((v >> 8) & 0xff);
3659 : *(sp + 1) = (png_byte)(v & 0xff);
3660 : }
3661 :
3662 : else if (a == 0)
3663 : {
3664 : /* Background is already in screen gamma */
3665 : *sp = (png_byte)((png_ptr->background.gray >> 8)
3666 : & 0xff);
3667 : *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
3668 : }
3669 :
3670 : else
3671 : {
3672 : png_uint_16 g, v, w;
3673 :
3674 : g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
3675 : png_composite_16(v, g, a, png_ptr->background_1.gray);
3676 : if (optimize != 0)
3677 : w = v;
3678 : else
3679 : w = gamma_16_from_1[(v & 0xff) >>
3680 : gamma_shift][v >> 8];
3681 : *sp = (png_byte)((w >> 8) & 0xff);
3682 : *(sp + 1) = (png_byte)(w & 0xff);
3683 : }
3684 : }
3685 : }
3686 : else
3687 : #endif
3688 : {
3689 : sp = row;
3690 : for (i = 0; i < row_width; i++, sp += 4)
3691 : {
3692 : png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
3693 : + *(sp + 3));
3694 :
3695 : if (a == 0)
3696 : {
3697 : *sp = (png_byte)((png_ptr->background.gray >> 8)
3698 : & 0xff);
3699 : *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
3700 : }
3701 :
3702 : else if (a < 0xffff)
3703 : {
3704 : png_uint_16 g, v;
3705 :
3706 : g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3707 : png_composite_16(v, g, a, png_ptr->background.gray);
3708 : *sp = (png_byte)((v >> 8) & 0xff);
3709 : *(sp + 1) = (png_byte)(v & 0xff);
3710 : }
3711 : }
3712 : }
3713 : }
3714 : break;
3715 : }
3716 :
3717 : case PNG_COLOR_TYPE_RGB_ALPHA:
3718 : {
3719 : if (row_info->bit_depth == 8)
3720 : {
3721 : #ifdef PNG_READ_GAMMA_SUPPORTED
3722 : if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
3723 : gamma_table != NULL)
3724 : {
3725 : sp = row;
3726 : for (i = 0; i < row_width; i++, sp += 4)
3727 : {
3728 : png_byte a = *(sp + 3);
3729 :
3730 : if (a == 0xff)
3731 : {
3732 : *sp = gamma_table[*sp];
3733 : *(sp + 1) = gamma_table[*(sp + 1)];
3734 : *(sp + 2) = gamma_table[*(sp + 2)];
3735 : }
3736 :
3737 : else if (a == 0)
3738 : {
3739 : /* Background is already in screen gamma */
3740 : *sp = (png_byte)png_ptr->background.red;
3741 : *(sp + 1) = (png_byte)png_ptr->background.green;
3742 : *(sp + 2) = (png_byte)png_ptr->background.blue;
3743 : }
3744 :
3745 : else
3746 : {
3747 : png_byte v, w;
3748 :
3749 : v = gamma_to_1[*sp];
3750 : png_composite(w, v, a, png_ptr->background_1.red);
3751 : if (optimize == 0) w = gamma_from_1[w];
3752 : *sp = w;
3753 :
3754 : v = gamma_to_1[*(sp + 1)];
3755 : png_composite(w, v, a, png_ptr->background_1.green);
3756 : if (optimize == 0) w = gamma_from_1[w];
3757 : *(sp + 1) = w;
3758 :
3759 : v = gamma_to_1[*(sp + 2)];
3760 : png_composite(w, v, a, png_ptr->background_1.blue);
3761 : if (optimize == 0) w = gamma_from_1[w];
3762 : *(sp + 2) = w;
3763 : }
3764 : }
3765 : }
3766 : else
3767 : #endif
3768 : {
3769 : sp = row;
3770 : for (i = 0; i < row_width; i++, sp += 4)
3771 : {
3772 : png_byte a = *(sp + 3);
3773 :
3774 : if (a == 0)
3775 : {
3776 : *sp = (png_byte)png_ptr->background.red;
3777 : *(sp + 1) = (png_byte)png_ptr->background.green;
3778 : *(sp + 2) = (png_byte)png_ptr->background.blue;
3779 : }
3780 :
3781 : else if (a < 0xff)
3782 : {
3783 : png_composite(*sp, *sp, a, png_ptr->background.red);
3784 :
3785 : png_composite(*(sp + 1), *(sp + 1), a,
3786 : png_ptr->background.green);
3787 :
3788 : png_composite(*(sp + 2), *(sp + 2), a,
3789 : png_ptr->background.blue);
3790 : }
3791 : }
3792 : }
3793 : }
3794 : else /* if (row_info->bit_depth == 16) */
3795 : {
3796 : #ifdef PNG_READ_GAMMA_SUPPORTED
3797 : if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
3798 : gamma_16_to_1 != NULL)
3799 : {
3800 : sp = row;
3801 : for (i = 0; i < row_width; i++, sp += 8)
3802 : {
3803 : png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
3804 : << 8) + (png_uint_16)(*(sp + 7)));
3805 :
3806 : if (a == (png_uint_16)0xffff)
3807 : {
3808 : png_uint_16 v;
3809 :
3810 : v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
3811 : *sp = (png_byte)((v >> 8) & 0xff);
3812 : *(sp + 1) = (png_byte)(v & 0xff);
3813 :
3814 : v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
3815 : *(sp + 2) = (png_byte)((v >> 8) & 0xff);
3816 : *(sp + 3) = (png_byte)(v & 0xff);
3817 :
3818 : v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
3819 : *(sp + 4) = (png_byte)((v >> 8) & 0xff);
3820 : *(sp + 5) = (png_byte)(v & 0xff);
3821 : }
3822 :
3823 : else if (a == 0)
3824 : {
3825 : /* Background is already in screen gamma */
3826 : *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
3827 : *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
3828 : *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
3829 : & 0xff);
3830 : *(sp + 3) = (png_byte)(png_ptr->background.green
3831 : & 0xff);
3832 : *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
3833 : & 0xff);
3834 : *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
3835 : }
3836 :
3837 : else
3838 : {
3839 : png_uint_16 v, w;
3840 :
3841 : v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
3842 : png_composite_16(w, v, a, png_ptr->background_1.red);
3843 : if (optimize == 0)
3844 : w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
3845 : 8];
3846 : *sp = (png_byte)((w >> 8) & 0xff);
3847 : *(sp + 1) = (png_byte)(w & 0xff);
3848 :
3849 : v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
3850 : png_composite_16(w, v, a, png_ptr->background_1.green);
3851 : if (optimize == 0)
3852 : w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
3853 : 8];
3854 :
3855 : *(sp + 2) = (png_byte)((w >> 8) & 0xff);
3856 : *(sp + 3) = (png_byte)(w & 0xff);
3857 :
3858 : v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
3859 : png_composite_16(w, v, a, png_ptr->background_1.blue);
3860 : if (optimize == 0)
3861 : w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
3862 : 8];
3863 :
3864 : *(sp + 4) = (png_byte)((w >> 8) & 0xff);
3865 : *(sp + 5) = (png_byte)(w & 0xff);
3866 : }
3867 : }
3868 : }
3869 :
3870 : else
3871 : #endif
3872 : {
3873 : sp = row;
3874 : for (i = 0; i < row_width; i++, sp += 8)
3875 : {
3876 : png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
3877 : << 8) + (png_uint_16)(*(sp + 7)));
3878 :
3879 : if (a == 0)
3880 : {
3881 : *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
3882 : *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
3883 : *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
3884 : & 0xff);
3885 : *(sp + 3) = (png_byte)(png_ptr->background.green
3886 : & 0xff);
3887 : *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
3888 : & 0xff);
3889 : *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
3890 : }
3891 :
3892 : else if (a < 0xffff)
3893 : {
3894 : png_uint_16 v;
3895 :
3896 : png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
3897 : png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
3898 : + *(sp + 3));
3899 : png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
3900 : + *(sp + 5));
3901 :
3902 : png_composite_16(v, r, a, png_ptr->background.red);
3903 : *sp = (png_byte)((v >> 8) & 0xff);
3904 : *(sp + 1) = (png_byte)(v & 0xff);
3905 :
3906 : png_composite_16(v, g, a, png_ptr->background.green);
3907 : *(sp + 2) = (png_byte)((v >> 8) & 0xff);
3908 : *(sp + 3) = (png_byte)(v & 0xff);
3909 :
3910 : png_composite_16(v, b, a, png_ptr->background.blue);
3911 : *(sp + 4) = (png_byte)((v >> 8) & 0xff);
3912 : *(sp + 5) = (png_byte)(v & 0xff);
3913 : }
3914 : }
3915 : }
3916 : }
3917 : break;
3918 : }
3919 :
3920 : default:
3921 : break;
3922 : }
3923 : }
3924 : }
3925 : #endif /* READ_BACKGROUND || READ_ALPHA_MODE */
3926 :
3927 : #ifdef PNG_READ_GAMMA_SUPPORTED
3928 : /* Gamma correct the image, avoiding the alpha channel. Make sure
3929 : * you do this after you deal with the transparency issue on grayscale
3930 : * or RGB images. If your bit depth is 8, use gamma_table, if it
3931 : * is 16, use gamma_16_table and gamma_shift. Build these with
3932 : * build_gamma_table().
3933 : */
3934 : static void
3935 0 : png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
3936 : {
3937 0 : png_const_bytep gamma_table = png_ptr->gamma_table;
3938 0 : png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table;
3939 0 : int gamma_shift = png_ptr->gamma_shift;
3940 :
3941 : png_bytep sp;
3942 : png_uint_32 i;
3943 0 : png_uint_32 row_width=row_info->width;
3944 :
3945 : png_debug(1, "in png_do_gamma");
3946 :
3947 0 : if (((row_info->bit_depth <= 8 && gamma_table != NULL) ||
3948 0 : (row_info->bit_depth == 16 && gamma_16_table != NULL)))
3949 : {
3950 0 : switch (row_info->color_type)
3951 : {
3952 : case PNG_COLOR_TYPE_RGB:
3953 : {
3954 0 : if (row_info->bit_depth == 8)
3955 : {
3956 0 : sp = row;
3957 0 : for (i = 0; i < row_width; i++)
3958 : {
3959 0 : *sp = gamma_table[*sp];
3960 0 : sp++;
3961 0 : *sp = gamma_table[*sp];
3962 0 : sp++;
3963 0 : *sp = gamma_table[*sp];
3964 0 : sp++;
3965 : }
3966 : }
3967 :
3968 : else /* if (row_info->bit_depth == 16) */
3969 : {
3970 0 : sp = row;
3971 0 : for (i = 0; i < row_width; i++)
3972 : {
3973 : png_uint_16 v;
3974 :
3975 0 : v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
3976 0 : *sp = (png_byte)((v >> 8) & 0xff);
3977 0 : *(sp + 1) = (png_byte)(v & 0xff);
3978 0 : sp += 2;
3979 :
3980 0 : v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
3981 0 : *sp = (png_byte)((v >> 8) & 0xff);
3982 0 : *(sp + 1) = (png_byte)(v & 0xff);
3983 0 : sp += 2;
3984 :
3985 0 : v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
3986 0 : *sp = (png_byte)((v >> 8) & 0xff);
3987 0 : *(sp + 1) = (png_byte)(v & 0xff);
3988 0 : sp += 2;
3989 : }
3990 : }
3991 0 : break;
3992 : }
3993 :
3994 : case PNG_COLOR_TYPE_RGB_ALPHA:
3995 : {
3996 0 : if (row_info->bit_depth == 8)
3997 : {
3998 0 : sp = row;
3999 0 : for (i = 0; i < row_width; i++)
4000 : {
4001 0 : *sp = gamma_table[*sp];
4002 0 : sp++;
4003 :
4004 0 : *sp = gamma_table[*sp];
4005 0 : sp++;
4006 :
4007 0 : *sp = gamma_table[*sp];
4008 0 : sp++;
4009 :
4010 0 : sp++;
4011 : }
4012 : }
4013 :
4014 : else /* if (row_info->bit_depth == 16) */
4015 : {
4016 0 : sp = row;
4017 0 : for (i = 0; i < row_width; i++)
4018 : {
4019 0 : png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4020 0 : *sp = (png_byte)((v >> 8) & 0xff);
4021 0 : *(sp + 1) = (png_byte)(v & 0xff);
4022 0 : sp += 2;
4023 :
4024 0 : v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4025 0 : *sp = (png_byte)((v >> 8) & 0xff);
4026 0 : *(sp + 1) = (png_byte)(v & 0xff);
4027 0 : sp += 2;
4028 :
4029 0 : v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4030 0 : *sp = (png_byte)((v >> 8) & 0xff);
4031 0 : *(sp + 1) = (png_byte)(v & 0xff);
4032 0 : sp += 4;
4033 : }
4034 : }
4035 0 : break;
4036 : }
4037 :
4038 : case PNG_COLOR_TYPE_GRAY_ALPHA:
4039 : {
4040 0 : if (row_info->bit_depth == 8)
4041 : {
4042 0 : sp = row;
4043 0 : for (i = 0; i < row_width; i++)
4044 : {
4045 0 : *sp = gamma_table[*sp];
4046 0 : sp += 2;
4047 : }
4048 : }
4049 :
4050 : else /* if (row_info->bit_depth == 16) */
4051 : {
4052 0 : sp = row;
4053 0 : for (i = 0; i < row_width; i++)
4054 : {
4055 0 : png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4056 0 : *sp = (png_byte)((v >> 8) & 0xff);
4057 0 : *(sp + 1) = (png_byte)(v & 0xff);
4058 0 : sp += 4;
4059 : }
4060 : }
4061 0 : break;
4062 : }
4063 :
4064 : case PNG_COLOR_TYPE_GRAY:
4065 : {
4066 0 : if (row_info->bit_depth == 2)
4067 : {
4068 0 : sp = row;
4069 0 : for (i = 0; i < row_width; i += 4)
4070 : {
4071 0 : int a = *sp & 0xc0;
4072 0 : int b = *sp & 0x30;
4073 0 : int c = *sp & 0x0c;
4074 0 : int d = *sp & 0x03;
4075 :
4076 0 : *sp = (png_byte)(
4077 0 : ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)]) ) & 0xc0)|
4078 0 : ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
4079 0 : ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
4080 0 : ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
4081 0 : sp++;
4082 : }
4083 : }
4084 :
4085 0 : if (row_info->bit_depth == 4)
4086 : {
4087 0 : sp = row;
4088 0 : for (i = 0; i < row_width; i += 2)
4089 : {
4090 0 : int msb = *sp & 0xf0;
4091 0 : int lsb = *sp & 0x0f;
4092 :
4093 0 : *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
4094 0 : | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
4095 0 : sp++;
4096 : }
4097 : }
4098 :
4099 0 : else if (row_info->bit_depth == 8)
4100 : {
4101 0 : sp = row;
4102 0 : for (i = 0; i < row_width; i++)
4103 : {
4104 0 : *sp = gamma_table[*sp];
4105 0 : sp++;
4106 : }
4107 : }
4108 :
4109 0 : else if (row_info->bit_depth == 16)
4110 : {
4111 0 : sp = row;
4112 0 : for (i = 0; i < row_width; i++)
4113 : {
4114 0 : png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
4115 0 : *sp = (png_byte)((v >> 8) & 0xff);
4116 0 : *(sp + 1) = (png_byte)(v & 0xff);
4117 0 : sp += 2;
4118 : }
4119 : }
4120 0 : break;
4121 : }
4122 :
4123 : default:
4124 0 : break;
4125 : }
4126 : }
4127 0 : }
4128 : #endif
4129 :
4130 : #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
4131 : /* Encode the alpha channel to the output gamma (the input channel is always
4132 : * linear.) Called only with color types that have an alpha channel. Needs the
4133 : * from_1 tables.
4134 : */
4135 : static void
4136 : png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
4137 : {
4138 : png_uint_32 row_width = row_info->width;
4139 :
4140 : png_debug(1, "in png_do_encode_alpha");
4141 :
4142 : if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
4143 : {
4144 : if (row_info->bit_depth == 8)
4145 : {
4146 : PNG_CONST png_bytep table = png_ptr->gamma_from_1;
4147 :
4148 : if (table != NULL)
4149 : {
4150 : PNG_CONST int step =
4151 : (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2;
4152 :
4153 : /* The alpha channel is the last component: */
4154 : row += step - 1;
4155 :
4156 : for (; row_width > 0; --row_width, row += step)
4157 : *row = table[*row];
4158 :
4159 : return;
4160 : }
4161 : }
4162 :
4163 : else if (row_info->bit_depth == 16)
4164 : {
4165 : PNG_CONST png_uint_16pp table = png_ptr->gamma_16_from_1;
4166 : PNG_CONST int gamma_shift = png_ptr->gamma_shift;
4167 :
4168 : if (table != NULL)
4169 : {
4170 : PNG_CONST int step =
4171 : (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4;
4172 :
4173 : /* The alpha channel is the last component: */
4174 : row += step - 2;
4175 :
4176 : for (; row_width > 0; --row_width, row += step)
4177 : {
4178 : png_uint_16 v;
4179 :
4180 : v = table[*(row + 1) >> gamma_shift][*row];
4181 : *row = (png_byte)((v >> 8) & 0xff);
4182 : *(row + 1) = (png_byte)(v & 0xff);
4183 : }
4184 :
4185 : return;
4186 : }
4187 : }
4188 : }
4189 :
4190 : /* Only get to here if called with a weird row_info; no harm has been done,
4191 : * so just issue a warning.
4192 : */
4193 : png_warning(png_ptr, "png_do_encode_alpha: unexpected call");
4194 : }
4195 : #endif
4196 :
4197 : #ifdef PNG_READ_EXPAND_SUPPORTED
4198 : /* Expands a palette row to an RGB or RGBA row depending
4199 : * upon whether you supply trans and num_trans.
4200 : */
4201 : static void
4202 17 : png_do_expand_palette(png_row_infop row_info, png_bytep row,
4203 : png_const_colorp palette, png_const_bytep trans_alpha, int num_trans)
4204 : {
4205 : int shift, value;
4206 : png_bytep sp, dp;
4207 : png_uint_32 i;
4208 17 : png_uint_32 row_width=row_info->width;
4209 :
4210 : png_debug(1, "in png_do_expand_palette");
4211 :
4212 17 : if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
4213 : {
4214 17 : if (row_info->bit_depth < 8)
4215 : {
4216 0 : switch (row_info->bit_depth)
4217 : {
4218 : case 1:
4219 : {
4220 0 : sp = row + (png_size_t)((row_width - 1) >> 3);
4221 0 : dp = row + (png_size_t)row_width - 1;
4222 0 : shift = 7 - (int)((row_width + 7) & 0x07);
4223 0 : for (i = 0; i < row_width; i++)
4224 : {
4225 0 : if ((*sp >> shift) & 0x01)
4226 0 : *dp = 1;
4227 :
4228 : else
4229 0 : *dp = 0;
4230 :
4231 0 : if (shift == 7)
4232 : {
4233 0 : shift = 0;
4234 0 : sp--;
4235 : }
4236 :
4237 : else
4238 0 : shift++;
4239 :
4240 0 : dp--;
4241 : }
4242 0 : break;
4243 : }
4244 :
4245 : case 2:
4246 : {
4247 0 : sp = row + (png_size_t)((row_width - 1) >> 2);
4248 0 : dp = row + (png_size_t)row_width - 1;
4249 0 : shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
4250 0 : for (i = 0; i < row_width; i++)
4251 : {
4252 0 : value = (*sp >> shift) & 0x03;
4253 0 : *dp = (png_byte)value;
4254 0 : if (shift == 6)
4255 : {
4256 0 : shift = 0;
4257 0 : sp--;
4258 : }
4259 :
4260 : else
4261 0 : shift += 2;
4262 :
4263 0 : dp--;
4264 : }
4265 0 : break;
4266 : }
4267 :
4268 : case 4:
4269 : {
4270 0 : sp = row + (png_size_t)((row_width - 1) >> 1);
4271 0 : dp = row + (png_size_t)row_width - 1;
4272 0 : shift = (int)((row_width & 0x01) << 2);
4273 0 : for (i = 0; i < row_width; i++)
4274 : {
4275 0 : value = (*sp >> shift) & 0x0f;
4276 0 : *dp = (png_byte)value;
4277 0 : if (shift == 4)
4278 : {
4279 0 : shift = 0;
4280 0 : sp--;
4281 : }
4282 :
4283 : else
4284 0 : shift += 4;
4285 :
4286 0 : dp--;
4287 : }
4288 0 : break;
4289 : }
4290 :
4291 : default:
4292 0 : break;
4293 : }
4294 0 : row_info->bit_depth = 8;
4295 0 : row_info->pixel_depth = 8;
4296 0 : row_info->rowbytes = row_width;
4297 : }
4298 :
4299 17 : if (row_info->bit_depth == 8)
4300 : {
4301 : {
4302 17 : if (num_trans > 0)
4303 : {
4304 17 : sp = row + (png_size_t)row_width - 1;
4305 17 : dp = row + ((png_size_t)row_width << 2) - 1;
4306 :
4307 272 : for (i = 0; i < row_width; i++)
4308 : {
4309 255 : if ((int)(*sp) >= num_trans)
4310 28 : *dp-- = 0xff;
4311 :
4312 : else
4313 227 : *dp-- = trans_alpha[*sp];
4314 :
4315 255 : *dp-- = palette[*sp].blue;
4316 255 : *dp-- = palette[*sp].green;
4317 255 : *dp-- = palette[*sp].red;
4318 255 : sp--;
4319 : }
4320 17 : row_info->bit_depth = 8;
4321 17 : row_info->pixel_depth = 32;
4322 17 : row_info->rowbytes = row_width * 4;
4323 17 : row_info->color_type = 6;
4324 17 : row_info->channels = 4;
4325 : }
4326 :
4327 : else
4328 : {
4329 0 : sp = row + (png_size_t)row_width - 1;
4330 0 : dp = row + (png_size_t)(row_width * 3) - 1;
4331 :
4332 0 : for (i = 0; i < row_width; i++)
4333 : {
4334 0 : *dp-- = palette[*sp].blue;
4335 0 : *dp-- = palette[*sp].green;
4336 0 : *dp-- = palette[*sp].red;
4337 0 : sp--;
4338 : }
4339 :
4340 0 : row_info->bit_depth = 8;
4341 0 : row_info->pixel_depth = 24;
4342 0 : row_info->rowbytes = row_width * 3;
4343 0 : row_info->color_type = 2;
4344 0 : row_info->channels = 3;
4345 : }
4346 : }
4347 : }
4348 : }
4349 17 : }
4350 :
4351 : /* If the bit depth < 8, it is expanded to 8. Also, if the already
4352 : * expanded transparency value is supplied, an alpha channel is built.
4353 : */
4354 : static void
4355 1521 : png_do_expand(png_row_infop row_info, png_bytep row,
4356 : png_const_color_16p trans_color)
4357 : {
4358 : int shift, value;
4359 : png_bytep sp, dp;
4360 : png_uint_32 i;
4361 1521 : png_uint_32 row_width=row_info->width;
4362 :
4363 : png_debug(1, "in png_do_expand");
4364 :
4365 : {
4366 1521 : if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
4367 : {
4368 0 : unsigned int gray = trans_color != NULL ? trans_color->gray : 0;
4369 :
4370 0 : if (row_info->bit_depth < 8)
4371 : {
4372 0 : switch (row_info->bit_depth)
4373 : {
4374 : case 1:
4375 : {
4376 0 : gray = (gray & 0x01) * 0xff;
4377 0 : sp = row + (png_size_t)((row_width - 1) >> 3);
4378 0 : dp = row + (png_size_t)row_width - 1;
4379 0 : shift = 7 - (int)((row_width + 7) & 0x07);
4380 0 : for (i = 0; i < row_width; i++)
4381 : {
4382 0 : if ((*sp >> shift) & 0x01)
4383 0 : *dp = 0xff;
4384 :
4385 : else
4386 0 : *dp = 0;
4387 :
4388 0 : if (shift == 7)
4389 : {
4390 0 : shift = 0;
4391 0 : sp--;
4392 : }
4393 :
4394 : else
4395 0 : shift++;
4396 :
4397 0 : dp--;
4398 : }
4399 0 : break;
4400 : }
4401 :
4402 : case 2:
4403 : {
4404 0 : gray = (gray & 0x03) * 0x55;
4405 0 : sp = row + (png_size_t)((row_width - 1) >> 2);
4406 0 : dp = row + (png_size_t)row_width - 1;
4407 0 : shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
4408 0 : for (i = 0; i < row_width; i++)
4409 : {
4410 0 : value = (*sp >> shift) & 0x03;
4411 0 : *dp = (png_byte)(value | (value << 2) | (value << 4) |
4412 0 : (value << 6));
4413 0 : if (shift == 6)
4414 : {
4415 0 : shift = 0;
4416 0 : sp--;
4417 : }
4418 :
4419 : else
4420 0 : shift += 2;
4421 :
4422 0 : dp--;
4423 : }
4424 0 : break;
4425 : }
4426 :
4427 : case 4:
4428 : {
4429 0 : gray = (gray & 0x0f) * 0x11;
4430 0 : sp = row + (png_size_t)((row_width - 1) >> 1);
4431 0 : dp = row + (png_size_t)row_width - 1;
4432 0 : shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
4433 0 : for (i = 0; i < row_width; i++)
4434 : {
4435 0 : value = (*sp >> shift) & 0x0f;
4436 0 : *dp = (png_byte)(value | (value << 4));
4437 0 : if (shift == 4)
4438 : {
4439 0 : shift = 0;
4440 0 : sp--;
4441 : }
4442 :
4443 : else
4444 0 : shift = 4;
4445 :
4446 0 : dp--;
4447 : }
4448 0 : break;
4449 : }
4450 :
4451 : default:
4452 0 : break;
4453 : }
4454 :
4455 0 : row_info->bit_depth = 8;
4456 0 : row_info->pixel_depth = 8;
4457 0 : row_info->rowbytes = row_width;
4458 : }
4459 :
4460 0 : if (trans_color != NULL)
4461 : {
4462 0 : if (row_info->bit_depth == 8)
4463 : {
4464 0 : gray = gray & 0xff;
4465 0 : sp = row + (png_size_t)row_width - 1;
4466 0 : dp = row + ((png_size_t)row_width << 1) - 1;
4467 :
4468 0 : for (i = 0; i < row_width; i++)
4469 : {
4470 0 : if ((*sp & 0xffU) == gray)
4471 0 : *dp-- = 0;
4472 :
4473 : else
4474 0 : *dp-- = 0xff;
4475 :
4476 0 : *dp-- = *sp--;
4477 : }
4478 : }
4479 :
4480 0 : else if (row_info->bit_depth == 16)
4481 : {
4482 0 : unsigned int gray_high = (gray >> 8) & 0xff;
4483 0 : unsigned int gray_low = gray & 0xff;
4484 0 : sp = row + row_info->rowbytes - 1;
4485 0 : dp = row + (row_info->rowbytes << 1) - 1;
4486 0 : for (i = 0; i < row_width; i++)
4487 : {
4488 0 : if ((*(sp - 1) & 0xffU) == gray_high &&
4489 0 : (*(sp) & 0xffU) == gray_low)
4490 : {
4491 0 : *dp-- = 0;
4492 0 : *dp-- = 0;
4493 : }
4494 :
4495 : else
4496 : {
4497 0 : *dp-- = 0xff;
4498 0 : *dp-- = 0xff;
4499 : }
4500 :
4501 0 : *dp-- = *sp--;
4502 0 : *dp-- = *sp--;
4503 : }
4504 : }
4505 :
4506 0 : row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
4507 0 : row_info->channels = 2;
4508 0 : row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
4509 0 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
4510 : row_width);
4511 : }
4512 : }
4513 1521 : else if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
4514 : trans_color != NULL)
4515 : {
4516 0 : if (row_info->bit_depth == 8)
4517 : {
4518 0 : png_byte red = (png_byte)(trans_color->red & 0xff);
4519 0 : png_byte green = (png_byte)(trans_color->green & 0xff);
4520 0 : png_byte blue = (png_byte)(trans_color->blue & 0xff);
4521 0 : sp = row + (png_size_t)row_info->rowbytes - 1;
4522 0 : dp = row + ((png_size_t)row_width << 2) - 1;
4523 0 : for (i = 0; i < row_width; i++)
4524 : {
4525 0 : if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
4526 0 : *dp-- = 0;
4527 :
4528 : else
4529 0 : *dp-- = 0xff;
4530 :
4531 0 : *dp-- = *sp--;
4532 0 : *dp-- = *sp--;
4533 0 : *dp-- = *sp--;
4534 : }
4535 : }
4536 0 : else if (row_info->bit_depth == 16)
4537 : {
4538 0 : png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
4539 0 : png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
4540 0 : png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
4541 0 : png_byte red_low = (png_byte)(trans_color->red & 0xff);
4542 0 : png_byte green_low = (png_byte)(trans_color->green & 0xff);
4543 0 : png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
4544 0 : sp = row + row_info->rowbytes - 1;
4545 0 : dp = row + ((png_size_t)row_width << 3) - 1;
4546 0 : for (i = 0; i < row_width; i++)
4547 : {
4548 0 : if (*(sp - 5) == red_high &&
4549 0 : *(sp - 4) == red_low &&
4550 0 : *(sp - 3) == green_high &&
4551 0 : *(sp - 2) == green_low &&
4552 0 : *(sp - 1) == blue_high &&
4553 0 : *(sp ) == blue_low)
4554 : {
4555 0 : *dp-- = 0;
4556 0 : *dp-- = 0;
4557 : }
4558 :
4559 : else
4560 : {
4561 0 : *dp-- = 0xff;
4562 0 : *dp-- = 0xff;
4563 : }
4564 :
4565 0 : *dp-- = *sp--;
4566 0 : *dp-- = *sp--;
4567 0 : *dp-- = *sp--;
4568 0 : *dp-- = *sp--;
4569 0 : *dp-- = *sp--;
4570 0 : *dp-- = *sp--;
4571 : }
4572 : }
4573 0 : row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
4574 0 : row_info->channels = 4;
4575 0 : row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
4576 0 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
4577 : }
4578 : }
4579 1521 : }
4580 : #endif
4581 :
4582 : #ifdef PNG_READ_EXPAND_16_SUPPORTED
4583 : /* If the bit depth is 8 and the color type is not a palette type expand the
4584 : * whole row to 16 bits. Has no effect otherwise.
4585 : */
4586 : static void
4587 : png_do_expand_16(png_row_infop row_info, png_bytep row)
4588 : {
4589 : if (row_info->bit_depth == 8 &&
4590 : row_info->color_type != PNG_COLOR_TYPE_PALETTE)
4591 : {
4592 : /* The row have a sequence of bytes containing [0..255] and we need
4593 : * to turn it into another row containing [0..65535], to do this we
4594 : * calculate:
4595 : *
4596 : * (input / 255) * 65535
4597 : *
4598 : * Which happens to be exactly input * 257 and this can be achieved
4599 : * simply by byte replication in place (copying backwards).
4600 : */
4601 : png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */
4602 : png_byte *dp = sp + row_info->rowbytes; /* destination, end + 1 */
4603 : while (dp > sp)
4604 : dp[-2] = dp[-1] = *--sp, dp -= 2;
4605 :
4606 : row_info->rowbytes *= 2;
4607 : row_info->bit_depth = 16;
4608 : row_info->pixel_depth = (png_byte)(row_info->channels * 16);
4609 : }
4610 : }
4611 : #endif
4612 :
4613 : #ifdef PNG_READ_QUANTIZE_SUPPORTED
4614 : static void
4615 : png_do_quantize(png_row_infop row_info, png_bytep row,
4616 : png_const_bytep palette_lookup, png_const_bytep quantize_lookup)
4617 : {
4618 : png_bytep sp, dp;
4619 : png_uint_32 i;
4620 : png_uint_32 row_width=row_info->width;
4621 :
4622 : png_debug(1, "in png_do_quantize");
4623 :
4624 : if (row_info->bit_depth == 8)
4625 : {
4626 : if (row_info->color_type == PNG_COLOR_TYPE_RGB && palette_lookup)
4627 : {
4628 : int r, g, b, p;
4629 : sp = row;
4630 : dp = row;
4631 : for (i = 0; i < row_width; i++)
4632 : {
4633 : r = *sp++;
4634 : g = *sp++;
4635 : b = *sp++;
4636 :
4637 : /* This looks real messy, but the compiler will reduce
4638 : * it down to a reasonable formula. For example, with
4639 : * 5 bits per color, we get:
4640 : * p = (((r >> 3) & 0x1f) << 10) |
4641 : * (((g >> 3) & 0x1f) << 5) |
4642 : * ((b >> 3) & 0x1f);
4643 : */
4644 : p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
4645 : ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
4646 : (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
4647 : (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
4648 : ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
4649 : (PNG_QUANTIZE_BLUE_BITS)) |
4650 : ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
4651 : ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
4652 :
4653 : *dp++ = palette_lookup[p];
4654 : }
4655 :
4656 : row_info->color_type = PNG_COLOR_TYPE_PALETTE;
4657 : row_info->channels = 1;
4658 : row_info->pixel_depth = row_info->bit_depth;
4659 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
4660 : }
4661 :
4662 : else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
4663 : palette_lookup != NULL)
4664 : {
4665 : int r, g, b, p;
4666 : sp = row;
4667 : dp = row;
4668 : for (i = 0; i < row_width; i++)
4669 : {
4670 : r = *sp++;
4671 : g = *sp++;
4672 : b = *sp++;
4673 : sp++;
4674 :
4675 : p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
4676 : ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
4677 : (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
4678 : (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
4679 : ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
4680 : (PNG_QUANTIZE_BLUE_BITS)) |
4681 : ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
4682 : ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
4683 :
4684 : *dp++ = palette_lookup[p];
4685 : }
4686 :
4687 : row_info->color_type = PNG_COLOR_TYPE_PALETTE;
4688 : row_info->channels = 1;
4689 : row_info->pixel_depth = row_info->bit_depth;
4690 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
4691 : }
4692 :
4693 : else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
4694 : quantize_lookup)
4695 : {
4696 : sp = row;
4697 :
4698 : for (i = 0; i < row_width; i++, sp++)
4699 : {
4700 : *sp = quantize_lookup[*sp];
4701 : }
4702 : }
4703 : }
4704 : }
4705 : #endif /* READ_QUANTIZE */
4706 :
4707 : /* Transform the row. The order of transformations is significant,
4708 : * and is very touchy. If you add a transformation, take care to
4709 : * decide how it fits in with the other transformations here.
4710 : */
4711 : void /* PRIVATE */
4712 1538 : png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
4713 : {
4714 : png_debug(1, "in png_do_read_transformations");
4715 :
4716 1538 : if (png_ptr->row_buf == NULL)
4717 : {
4718 : /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
4719 : * error is incredibly rare and incredibly easy to debug without this
4720 : * information.
4721 : */
4722 0 : png_error(png_ptr, "NULL row buffer");
4723 : }
4724 :
4725 : /* The following is debugging; prior to 1.5.4 the code was never compiled in;
4726 : * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
4727 : * PNG_WARN_UNINITIALIZED_ROW removed. In 1.6 the new flag is set only for
4728 : * all transformations, however in practice the ROW_INIT always gets done on
4729 : * demand, if necessary.
4730 : */
4731 3076 : if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
4732 1538 : (png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
4733 : {
4734 : /* Application has failed to call either png_read_start_image() or
4735 : * png_read_update_info() after setting transforms that expand pixels.
4736 : * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
4737 : */
4738 0 : png_error(png_ptr, "Uninitialized row");
4739 : }
4740 :
4741 : #ifdef PNG_READ_EXPAND_SUPPORTED
4742 1538 : if ((png_ptr->transformations & PNG_EXPAND) != 0)
4743 : {
4744 1538 : if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
4745 : {
4746 34 : png_do_expand_palette(row_info, png_ptr->row_buf + 1,
4747 34 : png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
4748 : }
4749 :
4750 : else
4751 : {
4752 1521 : if (png_ptr->num_trans != 0 &&
4753 0 : (png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
4754 0 : png_do_expand(row_info, png_ptr->row_buf + 1,
4755 0 : &(png_ptr->trans_color));
4756 :
4757 : else
4758 1521 : png_do_expand(row_info, png_ptr->row_buf + 1,
4759 : NULL);
4760 : }
4761 : }
4762 : #endif
4763 :
4764 : #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
4765 : if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
4766 : (png_ptr->transformations & PNG_COMPOSE) == 0 &&
4767 : (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
4768 : row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
4769 : png_do_strip_channel(row_info, png_ptr->row_buf + 1,
4770 : 0 /* at_start == false, because SWAP_ALPHA happens later */);
4771 : #endif
4772 :
4773 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
4774 : if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
4775 : {
4776 : int rgb_error =
4777 : png_do_rgb_to_gray(png_ptr, row_info,
4778 : png_ptr->row_buf + 1);
4779 :
4780 : if (rgb_error != 0)
4781 : {
4782 : png_ptr->rgb_to_gray_status=1;
4783 : if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
4784 : PNG_RGB_TO_GRAY_WARN)
4785 : png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
4786 :
4787 : if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
4788 : PNG_RGB_TO_GRAY_ERR)
4789 : png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
4790 : }
4791 : }
4792 : #endif
4793 :
4794 : /* From Andreas Dilger e-mail to png-implement, 26 March 1998:
4795 : *
4796 : * In most cases, the "simple transparency" should be done prior to doing
4797 : * gray-to-RGB, or you will have to test 3x as many bytes to check if a
4798 : * pixel is transparent. You would also need to make sure that the
4799 : * transparency information is upgraded to RGB.
4800 : *
4801 : * To summarize, the current flow is:
4802 : * - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
4803 : * with background "in place" if transparent,
4804 : * convert to RGB if necessary
4805 : * - Gray + alpha -> composite with gray background and remove alpha bytes,
4806 : * convert to RGB if necessary
4807 : *
4808 : * To support RGB backgrounds for gray images we need:
4809 : * - Gray + simple transparency -> convert to RGB + simple transparency,
4810 : * compare 3 or 6 bytes and composite with
4811 : * background "in place" if transparent
4812 : * (3x compare/pixel compared to doing
4813 : * composite with gray bkgrnd)
4814 : * - Gray + alpha -> convert to RGB + alpha, composite with background and
4815 : * remove alpha bytes (3x float
4816 : * operations/pixel compared with composite
4817 : * on gray background)
4818 : *
4819 : * Greg's change will do this. The reason it wasn't done before is for
4820 : * performance, as this increases the per-pixel operations. If we would check
4821 : * in advance if the background was gray or RGB, and position the gray-to-RGB
4822 : * transform appropriately, then it would save a lot of work/time.
4823 : */
4824 :
4825 : #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4826 : /* If gray -> RGB, do so now only if background is non-gray; else do later
4827 : * for performance reasons
4828 : */
4829 3076 : if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
4830 1538 : (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) == 0)
4831 1538 : png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
4832 : #endif
4833 :
4834 : #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
4835 : defined(PNG_READ_ALPHA_MODE_SUPPORTED)
4836 : if ((png_ptr->transformations & PNG_COMPOSE) != 0)
4837 : png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
4838 : #endif
4839 :
4840 : #ifdef PNG_READ_GAMMA_SUPPORTED
4841 1539 : if ((png_ptr->transformations & PNG_GAMMA) != 0 &&
4842 : #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
4843 : /* Because RGB_TO_GRAY does the gamma transform. */
4844 : (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0 &&
4845 : #endif
4846 : #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
4847 : defined(PNG_READ_ALPHA_MODE_SUPPORTED)
4848 : /* Because PNG_COMPOSE does the gamma transform if there is something to
4849 : * do (if there is an alpha channel or transparency.)
4850 : */
4851 : !((png_ptr->transformations & PNG_COMPOSE) != 0 &&
4852 : ((png_ptr->num_trans != 0) ||
4853 : (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)) &&
4854 : #endif
4855 : /* Because png_init_read_transformations transforms the palette, unless
4856 : * RGB_TO_GRAY will do the transform.
4857 : */
4858 0 : (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
4859 0 : png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
4860 : #endif
4861 :
4862 : #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
4863 : if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
4864 : (png_ptr->transformations & PNG_COMPOSE) != 0 &&
4865 : (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
4866 : row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
4867 : png_do_strip_channel(row_info, png_ptr->row_buf + 1,
4868 : 0 /* at_start == false, because SWAP_ALPHA happens later */);
4869 : #endif
4870 :
4871 : #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
4872 : if ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
4873 : (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
4874 : png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
4875 : #endif
4876 :
4877 : #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
4878 1539 : if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
4879 0 : png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
4880 : #endif
4881 :
4882 : #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
4883 : /* There is no harm in doing both of these because only one has any effect,
4884 : * by putting the 'scale' option first if the app asks for scale (either by
4885 : * calling the API or in a TRANSFORM flag) this is what happens.
4886 : */
4887 : if ((png_ptr->transformations & PNG_16_TO_8) != 0)
4888 : png_do_chop(row_info, png_ptr->row_buf + 1);
4889 : #endif
4890 :
4891 : #ifdef PNG_READ_QUANTIZE_SUPPORTED
4892 : if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
4893 : {
4894 : png_do_quantize(row_info, png_ptr->row_buf + 1,
4895 : png_ptr->palette_lookup, png_ptr->quantize_index);
4896 :
4897 : if (row_info->rowbytes == 0)
4898 : png_error(png_ptr, "png_do_quantize returned rowbytes=0");
4899 : }
4900 : #endif /* READ_QUANTIZE */
4901 :
4902 : #ifdef PNG_READ_EXPAND_16_SUPPORTED
4903 : /* Do the expansion now, after all the arithmetic has been done. Notice
4904 : * that previous transformations can handle the PNG_EXPAND_16 flag if this
4905 : * is efficient (particularly true in the case of gamma correction, where
4906 : * better accuracy results faster!)
4907 : */
4908 : if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
4909 : png_do_expand_16(row_info, png_ptr->row_buf + 1);
4910 : #endif
4911 :
4912 : #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
4913 : /* NOTE: moved here in 1.5.4 (from much later in this list.) */
4914 3078 : if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
4915 1539 : (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) != 0)
4916 0 : png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
4917 : #endif
4918 :
4919 : #ifdef PNG_READ_INVERT_SUPPORTED
4920 : if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
4921 : png_do_invert(row_info, png_ptr->row_buf + 1);
4922 : #endif
4923 :
4924 : #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
4925 : if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
4926 : png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
4927 : #endif
4928 :
4929 : #ifdef PNG_READ_SHIFT_SUPPORTED
4930 : if ((png_ptr->transformations & PNG_SHIFT) != 0)
4931 : png_do_unshift(row_info, png_ptr->row_buf + 1,
4932 : &(png_ptr->shift));
4933 : #endif
4934 :
4935 : #ifdef PNG_READ_PACK_SUPPORTED
4936 : if ((png_ptr->transformations & PNG_PACK) != 0)
4937 : png_do_unpack(row_info, png_ptr->row_buf + 1);
4938 : #endif
4939 :
4940 : #ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
4941 : /* Added at libpng-1.5.10 */
4942 : if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
4943 : png_ptr->num_palette_max >= 0)
4944 : png_do_check_palette_indexes(png_ptr, row_info);
4945 : #endif
4946 :
4947 : #ifdef PNG_READ_BGR_SUPPORTED
4948 : if ((png_ptr->transformations & PNG_BGR) != 0)
4949 : png_do_bgr(row_info, png_ptr->row_buf + 1);
4950 : #endif
4951 :
4952 : #ifdef PNG_READ_PACKSWAP_SUPPORTED
4953 : if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
4954 : png_do_packswap(row_info, png_ptr->row_buf + 1);
4955 : #endif
4956 :
4957 : #ifdef PNG_READ_FILLER_SUPPORTED
4958 : if ((png_ptr->transformations & PNG_FILLER) != 0)
4959 : png_do_read_filler(row_info, png_ptr->row_buf + 1,
4960 : (png_uint_32)png_ptr->filler, png_ptr->flags);
4961 : #endif
4962 :
4963 : #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
4964 : if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
4965 : png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
4966 : #endif
4967 :
4968 : #ifdef PNG_READ_16BIT_SUPPORTED
4969 : #ifdef PNG_READ_SWAP_SUPPORTED
4970 : if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
4971 : png_do_swap(row_info, png_ptr->row_buf + 1);
4972 : #endif
4973 : #endif
4974 :
4975 : #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
4976 : if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
4977 : {
4978 : if (png_ptr->read_user_transform_fn != NULL)
4979 : (*(png_ptr->read_user_transform_fn)) /* User read transform function */
4980 : (png_ptr, /* png_ptr */
4981 : row_info, /* row_info: */
4982 : /* png_uint_32 width; width of row */
4983 : /* png_size_t rowbytes; number of bytes in row */
4984 : /* png_byte color_type; color type of pixels */
4985 : /* png_byte bit_depth; bit depth of samples */
4986 : /* png_byte channels; number of channels (1-4) */
4987 : /* png_byte pixel_depth; bits per pixel (depth*channels) */
4988 : png_ptr->row_buf + 1); /* start of pixel data for row */
4989 : #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
4990 : if (png_ptr->user_transform_depth != 0)
4991 : row_info->bit_depth = png_ptr->user_transform_depth;
4992 :
4993 : if (png_ptr->user_transform_channels != 0)
4994 : row_info->channels = png_ptr->user_transform_channels;
4995 : #endif
4996 : row_info->pixel_depth = (png_byte)(row_info->bit_depth *
4997 : row_info->channels);
4998 :
4999 : row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
5000 : }
5001 : #endif
5002 1539 : }
5003 :
5004 : #endif /* READ_TRANSFORMS */
5005 : #endif /* READ */
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