1
2 /* pngstest.c
3 *
4 * Copyright (c) 2021 Cosmin Truta
5 * Copyright (c) 2013-2017 John Cunningham Bowler
6 *
7 * This code is released under the libpng license.
8 * For conditions of distribution and use, see the disclaimer
9 * and license in png.h
10 *
11 * Test for the PNG 'simplified' APIs.
12 */
13
14 #define _ISOC90_SOURCE 1
15 #define MALLOC_CHECK_ 2 /*glibc facility: turn on debugging*/
16
17 #include <stddef.h>
18 #include <stdlib.h>
19 #include <string.h>
20 #include <stdio.h>
21 #include <errno.h>
22 #include <ctype.h>
23 #include <math.h>
24
25 #if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
26 # include <config.h>
27 #endif
28
29 /* Define the following to use this test against your installed libpng, rather
30 * than the one being built here:
31 */
32 #ifdef PNG_FREESTANDING_TESTS
33 # include <png.h>
34 #else
35 # include "../../png.h"
36 #endif
37
38 /* 1.6.1 added support for the configure test harness, which uses 77 to indicate
39 * a skipped test, in earlier versions we need to succeed on a skipped test, so:
40 */
41 #if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
42 # define SKIP 77
43 #else
44 # define SKIP 0
45 #endif
46
47 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED /* Else nothing can be done */
48 #include "../tools/sRGB.h"
49
50 /* KNOWN ISSUES
51 *
52 * These defines switch on alternate algorithms for format conversions to match
53 * the current libpng implementation; they are set to allow pngstest to pass
54 * even though libpng is producing answers that are not as correct as they
55 * should be.
56 */
57 #define ALLOW_UNUSED_GPC 0
58 /* If true include unused static GPC functions and declare an external array
59 * of them to hide the fact that they are unused. This is for development
60 * use while testing the correct function to use to take into account libpng
61 * misbehavior, such as using a simple power law to correct sRGB to linear.
62 */
63
64 /* The following is to support direct compilation of this file as C++ */
65 #ifdef __cplusplus
66 # define voidcast(type, value) static_cast<type>(value)
67 # define aligncastconst(type, value) \
68 static_cast<type>(static_cast<const void*>(value))
69 #else
70 # define voidcast(type, value) (value)
71 # define aligncastconst(type, value) ((const void*)(value))
72 #endif /* __cplusplus */
73
74 /* During parallel runs of pngstest each temporary file needs a unique name,
75 * this is used to permit uniqueness using a command line argument which can be
76 * up to 22 characters long.
77 */
78 static char tmpf[23] = "TMP";
79
80 /* Generate random bytes. This uses a boring repeatable algorithm and it
81 * is implemented here so that it gives the same set of numbers on every
82 * architecture. It's a linear congruential generator (Knuth or Sedgewick
83 * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
84 * Hill, "The Art of Electronics".
85 */
86 static void
87 make_random_bytes(png_uint_32* seed, void* pv, size_t size)
88 {
89 png_uint_32 u0 = seed[0], u1 = seed[1];
90 png_bytep bytes = voidcast(png_bytep, pv);
91
92 /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
93 * bit-20. The top 1 bit is in u1, the bottom 32 are in u0.
94 */
95 size_t i;
96 for (i=0; i<size; ++i)
97 {
98 /* First generate 8 new bits then shift them in at the end. */
99 png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
100 u1 <<= 8;
101 u1 |= u0 >> 24;
102 u0 <<= 8;
103 u0 |= u;
104 *bytes++ = (png_byte)u;
105 }
106
107 seed[0] = u0;
108 seed[1] = u1;
109 }
110
111 static png_uint_32 color_seed[2];
112
113 static void
114 reseed(void)
115 {
116 color_seed[0] = 0x12345678U;
117 color_seed[1] = 0x9abcdefU;
118 }
119
120 static void
121 random_color(png_colorp color)
122 {
123 make_random_bytes(color_seed, color, sizeof *color);
124 }
125
126 /* Math support - neither Cygwin nor Visual Studio have C99 support and we need
127 * a predictable rounding function, so make one here:
128 */
129 static double
130 closestinteger(double x)
131 {
132 return floor(x + .5);
133 }
134
135 /* Cast support: remove GCC whines. */
136 static png_byte
137 u8d(double d)
138 {
139 d = closestinteger(d);
140 return (png_byte)d;
141 }
142
143 static png_uint_16
144 u16d(double d)
145 {
146 d = closestinteger(d);
147 return (png_uint_16)d;
148 }
149
150 /* sRGB support: use exact calculations rounded to the nearest int, see the
151 * fesetround() call in main(). sRGB_to_d optimizes the 8 to 16-bit conversion.
152 */
153 static double sRGB_to_d[256];
154 static double g22_to_d[256];
155
156 static void
157 init_sRGB_to_d(void)
158 {
159 int i;
160
161 sRGB_to_d[0] = 0;
162 for (i=1; i<255; ++i)
163 sRGB_to_d[i] = linear_from_sRGB(i/255.);
164 sRGB_to_d[255] = 1;
165
166 g22_to_d[0] = 0;
167 for (i=1; i<255; ++i)
168 g22_to_d[i] = pow(i/255., 1/.45455);
169 g22_to_d[255] = 1;
170 }
171
172 static png_byte
173 sRGB(double linear /*range 0.0 .. 1.0*/)
174 {
175 return u8d(255 * sRGB_from_linear(linear));
176 }
177
178 static png_byte
179 isRGB(int fixed_linear)
180 {
181 return sRGB(fixed_linear / 65535.);
182 }
183
184 #if 0 /* not used */
185 static png_byte
186 unpremultiply(int component, int alpha)
187 {
188 if (alpha <= component)
189 return 255; /* Arbitrary, but consistent with the libpng code */
190
191 else if (alpha >= 65535)
192 return isRGB(component);
193
194 else
195 return sRGB((double)component / alpha);
196 }
197 #endif
198
199 static png_uint_16
200 ilinear(int fixed_srgb)
201 {
202 return u16d(65535 * sRGB_to_d[fixed_srgb]);
203 }
204
205 static png_uint_16
206 ilineara(int fixed_srgb, int alpha)
207 {
208 return u16d((257 * alpha) * sRGB_to_d[fixed_srgb]);
209 }
210
211 static png_uint_16
212 ilinear_g22(int fixed_srgb)
213 {
214 return u16d(65535 * g22_to_d[fixed_srgb]);
215 }
216
217 #if ALLOW_UNUSED_GPC
218 static png_uint_16
219 ilineara_g22(int fixed_srgb, int alpha)
220 {
221 return u16d((257 * alpha) * g22_to_d[fixed_srgb]);
222 }
223 #endif
224
225 static double
226 YfromRGBint(int ir, int ig, int ib)
227 {
228 double r = ir;
229 double g = ig;
230 double b = ib;
231 return YfromRGB(r, g, b);
232 }
233
234 #if 0 /* unused */
235 /* The error that results from using a 2.2 power law in place of the correct
236 * sRGB transform, given an 8-bit value which might be either sRGB or power-law.
237 */
238 static int
239 power_law_error8(int value)
240 {
241 if (value > 0 && value < 255)
242 {
243 double vd = value / 255.;
244 double e = fabs(
245 pow(sRGB_to_d[value], 1/2.2) - sRGB_from_linear(pow(vd, 2.2)));
246
247 /* Always allow an extra 1 here for rounding errors */
248 e = 1+floor(255 * e);
249 return (int)e;
250 }
251
252 return 0;
253 }
254
255 static int error_in_sRGB_roundtrip = 56; /* by experiment */
256 static int
257 power_law_error16(int value)
258 {
259 if (value > 0 && value < 65535)
260 {
261 /* Round trip the value through an 8-bit representation but using
262 * non-matching to/from conversions.
263 */
264 double vd = value / 65535.;
265 double e = fabs(
266 pow(sRGB_from_linear(vd), 2.2) - linear_from_sRGB(pow(vd, 1/2.2)));
267
268 /* Always allow an extra 1 here for rounding errors */
269 e = error_in_sRGB_roundtrip+floor(65535 * e);
270 return (int)e;
271 }
272
273 return 0;
274 }
275
276 static int
277 compare_8bit(int v1, int v2, int error_limit, int multiple_algorithms)
278 {
279 int e = abs(v1-v2);
280 int ev1, ev2;
281
282 if (e <= error_limit)
283 return 1;
284
285 if (!multiple_algorithms)
286 return 0;
287
288 ev1 = power_law_error8(v1);
289 if (e <= ev1)
290 return 1;
291
292 ev2 = power_law_error8(v2);
293 if (e <= ev2)
294 return 1;
295
296 return 0;
297 }
298
299 static int
300 compare_16bit(int v1, int v2, int error_limit, int multiple_algorithms)
301 {
302 int e = abs(v1-v2);
303 int ev1, ev2;
304
305 if (e <= error_limit)
306 return 1;
307
308 /* "multiple_algorithms" in this case means that a color-map has been
309 * involved somewhere, so we can deduce that the values were forced to 8-bit
310 * (like the via_linear case for 8-bit.)
311 */
312 if (!multiple_algorithms)
313 return 0;
314
315 ev1 = power_law_error16(v1);
316 if (e <= ev1)
317 return 1;
318
319 ev2 = power_law_error16(v2);
320 if (e <= ev2)
321 return 1;
322
323 return 0;
324 }
325 #endif /* unused */
326
327 #define USE_FILE 1 /* else memory */
328 #define USE_STDIO 2 /* else use file name */
329 #define STRICT 4 /* fail on warnings too */
330 #define VERBOSE 8
331 #define KEEP_TMPFILES 16 /* else delete temporary files */
332 #define KEEP_GOING 32
333 #define ACCUMULATE 64
334 #define FAST_WRITE 128
335 #define sRGB_16BIT 256
336 #define NO_RESEED 512 /* do not reseed on each new file */
337 #define GBG_ERROR 1024 /* do not ignore the gamma+background_rgb_to_gray
338 * libpng warning. */
339
340 static void
341 print_opts(png_uint_32 opts)
342 {
343 if (opts & USE_FILE)
344 printf(" --file");
345 if (opts & USE_STDIO)
346 printf(" --stdio");
347 if (!(opts & STRICT))
348 printf(" --nostrict");
349 if (opts & VERBOSE)
350 printf(" --verbose");
351 if (opts & KEEP_TMPFILES)
352 printf(" --preserve");
353 if (opts & KEEP_GOING)
354 printf(" --keep-going");
355 if (opts & ACCUMULATE)
356 printf(" --accumulate");
357 if (!(opts & FAST_WRITE)) /* --fast is currently the default */
358 printf(" --slow");
359 if (opts & sRGB_16BIT)
360 printf(" --sRGB-16bit");
361 if (opts & NO_RESEED)
362 printf(" --noreseed");
363 #if PNG_LIBPNG_VER < 10700 /* else on by default */
364 if (opts & GBG_ERROR)
365 printf(" --fault-gbg-warning");
366 #endif
367 }
368
369 #define FORMAT_NO_CHANGE 0x80000000 /* additional flag */
370
371 /* A name table for all the formats - defines the format of the '+' arguments to
372 * pngstest.
373 */
374 #define FORMAT_COUNT 64
375 #define FORMAT_MASK 0x3f
376 static const char * const format_names[FORMAT_COUNT] =
377 {
378 "sRGB-gray",
379 "sRGB-gray+alpha",
380 "sRGB-rgb",
381 "sRGB-rgb+alpha",
382 "linear-gray",
383 "linear-gray+alpha",
384 "linear-rgb",
385 "linear-rgb+alpha",
386
387 "color-mapped-sRGB-gray",
388 "color-mapped-sRGB-gray+alpha",
389 "color-mapped-sRGB-rgb",
390 "color-mapped-sRGB-rgb+alpha",
391 "color-mapped-linear-gray",
392 "color-mapped-linear-gray+alpha",
393 "color-mapped-linear-rgb",
394 "color-mapped-linear-rgb+alpha",
395
396 "sRGB-gray",
397 "sRGB-gray+alpha",
398 "sRGB-bgr",
399 "sRGB-bgr+alpha",
400 "linear-gray",
401 "linear-gray+alpha",
402 "linear-bgr",
403 "linear-bgr+alpha",
404
405 "color-mapped-sRGB-gray",
406 "color-mapped-sRGB-gray+alpha",
407 "color-mapped-sRGB-bgr",
408 "color-mapped-sRGB-bgr+alpha",
409 "color-mapped-linear-gray",
410 "color-mapped-linear-gray+alpha",
411 "color-mapped-linear-bgr",
412 "color-mapped-linear-bgr+alpha",
413
414 "sRGB-gray",
415 "alpha+sRGB-gray",
416 "sRGB-rgb",
417 "alpha+sRGB-rgb",
418 "linear-gray",
419 "alpha+linear-gray",
420 "linear-rgb",
421 "alpha+linear-rgb",
422
423 "color-mapped-sRGB-gray",
424 "color-mapped-alpha+sRGB-gray",
425 "color-mapped-sRGB-rgb",
426 "color-mapped-alpha+sRGB-rgb",
427 "color-mapped-linear-gray",
428 "color-mapped-alpha+linear-gray",
429 "color-mapped-linear-rgb",
430 "color-mapped-alpha+linear-rgb",
431
432 "sRGB-gray",
433 "alpha+sRGB-gray",
434 "sRGB-bgr",
435 "alpha+sRGB-bgr",
436 "linear-gray",
437 "alpha+linear-gray",
438 "linear-bgr",
439 "alpha+linear-bgr",
440
441 "color-mapped-sRGB-gray",
442 "color-mapped-alpha+sRGB-gray",
443 "color-mapped-sRGB-bgr",
444 "color-mapped-alpha+sRGB-bgr",
445 "color-mapped-linear-gray",
446 "color-mapped-alpha+linear-gray",
447 "color-mapped-linear-bgr",
448 "color-mapped-alpha+linear-bgr",
449 };
450
451 /* Decode an argument to a format number. */
452 static png_uint_32
453 formatof(const char *arg)
454 {
455 char *ep;
456 unsigned long format = strtoul(arg, &ep, 0);
457
458 if (ep > arg && *ep == 0 && format < FORMAT_COUNT)
459 return (png_uint_32)format;
460
461 else for (format=0; format < FORMAT_COUNT; ++format)
462 {
463 if (strcmp(format_names[format], arg) == 0)
464 return (png_uint_32)format;
465 }
466
467 fprintf(stderr, "pngstest: format name '%s' invalid\n", arg);
468 return FORMAT_COUNT;
469 }
470
471 /* Bitset/test functions for formats */
472 #define FORMAT_SET_COUNT (FORMAT_COUNT / 32)
473 typedef struct
474 {
475 png_uint_32 bits[FORMAT_SET_COUNT];
476 }
477 format_list;
478
479 static void format_init(format_list *pf)
480 {
481 int i;
482 for (i=0; i<FORMAT_SET_COUNT; ++i)
483 pf->bits[i] = 0; /* All off */
484 }
485
486 #if 0 /* currently unused */
487 static void format_clear(format_list *pf)
488 {
489 int i;
490 for (i=0; i<FORMAT_SET_COUNT; ++i)
491 pf->bits[i] = 0;
492 }
493 #endif
494
495 static int format_is_initial(format_list *pf)
496 {
497 int i;
498 for (i=0; i<FORMAT_SET_COUNT; ++i)
499 if (pf->bits[i] != 0)
500 return 0;
501
502 return 1;
503 }
504
505 static int format_set(format_list *pf, png_uint_32 format)
506 {
507 if (format < FORMAT_COUNT)
508 return pf->bits[format >> 5] |= ((png_uint_32)1) << (format & 31);
509
510 return 0;
511 }
512
513 #if 0 /* currently unused */
514 static int format_unset(format_list *pf, png_uint_32 format)
515 {
516 if (format < FORMAT_COUNT)
517 return pf->bits[format >> 5] &= ~((png_uint_32)1) << (format & 31);
518
519 return 0;
520 }
521 #endif
522
523 static int format_isset(format_list *pf, png_uint_32 format)
524 {
525 return format < FORMAT_COUNT &&
526 (pf->bits[format >> 5] & (((png_uint_32)1) << (format & 31))) != 0;
527 }
528
529 static void format_default(format_list *pf, int redundant)
530 {
531 if (redundant)
532 {
533 int i;
534
535 /* set everything, including flags that are pointless */
536 for (i=0; i<FORMAT_SET_COUNT; ++i)
537 pf->bits[i] = ~(png_uint_32)0;
538 }
539
540 else
541 {
542 png_uint_32 f;
543
544 for (f=0; f<FORMAT_COUNT; ++f)
545 {
546 /* Eliminate redundant and unsupported settings. */
547 # ifdef PNG_FORMAT_BGR_SUPPORTED
548 /* BGR is meaningless if no color: */
549 if ((f & PNG_FORMAT_FLAG_COLOR) == 0 &&
550 (f & PNG_FORMAT_FLAG_BGR) != 0)
551 # else
552 if ((f & 0x10U/*HACK: fixed value*/) != 0)
553 # endif
554 continue;
555
556 /* AFIRST is meaningless if no alpha: */
557 # ifdef PNG_FORMAT_AFIRST_SUPPORTED
558 if ((f & PNG_FORMAT_FLAG_ALPHA) == 0 &&
559 (f & PNG_FORMAT_FLAG_AFIRST) != 0)
560 # else
561 if ((f & 0x20U/*HACK: fixed value*/) != 0)
562 # endif
563 continue;
564
565 format_set(pf, f);
566 }
567 }
568 }
569
570 /* THE Image STRUCTURE */
571 /* The super-class of a png_image, contains the decoded image plus the input
572 * data necessary to re-read the file with a different format.
573 */
574 typedef struct
575 {
576 png_image image;
577 png_uint_32 opts;
578 const char *file_name;
579 int stride_extra;
580 FILE *input_file;
581 png_voidp input_memory;
582 size_t input_memory_size;
583 png_bytep buffer;
584 ptrdiff_t stride;
585 size_t bufsize;
586 size_t allocsize;
587 char tmpfile_name[32];
588 png_uint_16 colormap[256*4];
589 }
590 Image;
591
592 /* Initializer: also sets the permitted error limit for 16-bit operations. */
593 static void
594 newimage(Image *image)
595 {
596 memset(image, 0, sizeof *image);
597 }
598
599 /* Reset the image to be read again - only needs to rewind the FILE* at present.
600 */
601 static void
602 resetimage(Image *image)
603 {
604 if (image->input_file != NULL)
605 rewind(image->input_file);
606 }
607
608 /* Free the image buffer; the buffer is re-used on a re-read, this is just for
609 * cleanup.
610 */
611 static void
612 freebuffer(Image *image)
613 {
614 if (image->buffer) free(image->buffer);
615 image->buffer = NULL;
616 image->bufsize = 0;
617 image->allocsize = 0;
618 }
619
620 /* Delete function; cleans out all the allocated data and the temporary file in
621 * the image.
622 */
623 static void
624 freeimage(Image *image)
625 {
626 freebuffer(image);
627 png_image_free(&image->image);
628
629 if (image->input_file != NULL)
630 {
631 fclose(image->input_file);
632 image->input_file = NULL;
633 }
634
635 if (image->input_memory != NULL)
636 {
637 free(image->input_memory);
638 image->input_memory = NULL;
639 image->input_memory_size = 0;
640 }
641
642 if (image->tmpfile_name[0] != 0 && (image->opts & KEEP_TMPFILES) == 0)
643 {
644 (void)remove(image->tmpfile_name);
645 image->tmpfile_name[0] = 0;
646 }
647 }
648
649 /* This is actually a re-initializer; allows an image structure to be re-used by
650 * freeing everything that relates to an old image.
651 */
652 static void initimage(Image *image, png_uint_32 opts, const char *file_name,
653 int stride_extra)
654 {
655 freeimage(image);
656 memset(&image->image, 0, sizeof image->image);
657 image->opts = opts;
658 image->file_name = file_name;
659 image->stride_extra = stride_extra;
660 }
661
662 /* Make sure the image buffer is big enough; allows re-use of the buffer if the
663 * image is re-read.
664 */
665 #define BUFFER_INIT8 73
666 static void
667 allocbuffer(Image *image)
668 {
669 size_t size = PNG_IMAGE_BUFFER_SIZE(image->image, image->stride);
670
671 if (size+32 > image->bufsize)
672 {
673 freebuffer(image);
674 image->buffer = voidcast(png_bytep, malloc(size+32));
675 if (image->buffer == NULL)
676 {
677 fflush(stdout);
678 fprintf(stderr,
679 "simpletest: out of memory allocating %lu(+32) byte buffer\n",
680 (unsigned long)size);
681 exit(1);
682 }
683 image->bufsize = size+32;
684 }
685
686 memset(image->buffer, 95, image->bufsize);
687 memset(image->buffer+16, BUFFER_INIT8, size);
688 image->allocsize = size;
689 }
690
691 /* Make sure 16 bytes match the given byte. */
692 static int
693 check16(png_const_bytep bp, int b)
694 {
695 int i = 16;
696
697 do
698 if (*bp != b) return 1;
699 while (--i);
700
701 return 0;
702 }
703
704 /* Check for overwrite in the image buffer. */
705 static void
706 checkbuffer(Image *image, const char *arg)
707 {
708 if (check16(image->buffer, 95))
709 {
710 fflush(stdout);
711 fprintf(stderr, "%s: overwrite at start of image buffer\n", arg);
712 exit(1);
713 }
714
715 if (check16(image->buffer+16+image->allocsize, 95))
716 {
717 fflush(stdout);
718 fprintf(stderr, "%s: overwrite at end of image buffer\n", arg);
719 exit(1);
720 }
721 }
722
723 /* ERROR HANDLING */
724 /* Log a terminal error, also frees the libpng part of the image if necessary.
725 */
726 static int
727 logerror(Image *image, const char *a1, const char *a2, const char *a3)
728 {
729 fflush(stdout);
730 if (image->image.warning_or_error)
731 fprintf(stderr, "%s%s%s: %s\n", a1, a2, a3, image->image.message);
732
733 else
734 fprintf(stderr, "%s%s%s\n", a1, a2, a3);
735
736 if (image->image.opaque != NULL)
737 {
738 fprintf(stderr, "%s: image opaque pointer non-NULL on error\n",
739 image->file_name);
740 png_image_free(&image->image);
741 }
742
743 return 0;
744 }
745
746 /* Log an error and close a file (just a utility to do both things in one
747 * function call.)
748 */
749 static int
750 logclose(Image *image, FILE *f, const char *name, const char *operation)
751 {
752 int e = errno;
753
754 fclose(f);
755 return logerror(image, name, operation, strerror(e));
756 }
757
758 /* Make sure the png_image has been freed - validates that libpng is doing what
759 * the spec says and freeing the image.
760 */
761 static int
762 checkopaque(Image *image)
763 {
764 if (image->image.opaque != NULL)
765 {
766 png_image_free(&image->image);
767 return logerror(image, image->file_name, ": opaque not NULL", "");
768 }
769
770 /* Separate out the gamma+background_rgb_to_gray warning because it may
771 * produce opaque component errors:
772 */
773 else if (image->image.warning_or_error != 0 &&
774 (strcmp(image->image.message,
775 "libpng does not support gamma+background+rgb_to_gray") == 0 ?
776 (image->opts & GBG_ERROR) != 0 : (image->opts & STRICT) != 0))
777 return logerror(image, image->file_name, (image->opts & GBG_ERROR) != 0 ?
778 " --fault-gbg-warning" : " --strict", "");
779
780 else
781 return 1;
782 }
783
784 /* IMAGE COMPARISON/CHECKING */
785 /* Compare the pixels of two images, which should be the same but aren't. The
786 * images must have been checked for a size match.
787 */
788 typedef struct
789 {
790 /* The components, for grayscale images the gray value is in 'g' and if alpha
791 * is not present 'a' is set to 255 or 65535 according to format.
792 */
793 int r, g, b, a;
794 } Pixel;
795
796 typedef struct
797 {
798 /* The background as the original sRGB 8-bit value converted to the final
799 * integer format and as a double precision linear value in the range 0..1
800 * for with partially transparent pixels.
801 */
802 int ir, ig, ib;
803 double dr, dg, db; /* linear r,g,b scaled to 0..1 */
804 } Background;
805
806 /* Basic image formats; control the data but not the layout thereof. */
807 #define BASE_FORMATS\
808 (PNG_FORMAT_FLAG_ALPHA|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_LINEAR)
809
810 /* Read a Pixel from a buffer. The code below stores the correct routine for
811 * the format in a function pointer, these are the routines:
812 */
813 static void
814 gp_g8(Pixel *p, png_const_voidp pb)
815 {
816 png_const_bytep pp = voidcast(png_const_bytep, pb);
817
818 p->r = p->g = p->b = pp[0];
819 p->a = 255;
820 }
821
822 static void
823 gp_ga8(Pixel *p, png_const_voidp pb)
824 {
825 png_const_bytep pp = voidcast(png_const_bytep, pb);
826
827 p->r = p->g = p->b = pp[0];
828 p->a = pp[1];
829 }
830
831 #ifdef PNG_FORMAT_AFIRST_SUPPORTED
832 static void
833 gp_ag8(Pixel *p, png_const_voidp pb)
834 {
835 png_const_bytep pp = voidcast(png_const_bytep, pb);
836
837 p->r = p->g = p->b = pp[1];
838 p->a = pp[0];
839 }
840 #endif
841
842 static void
843 gp_rgb8(Pixel *p, png_const_voidp pb)
844 {
845 png_const_bytep pp = voidcast(png_const_bytep, pb);
846
847 p->r = pp[0];
848 p->g = pp[1];
849 p->b = pp[2];
850 p->a = 255;
851 }
852
853 #ifdef PNG_FORMAT_BGR_SUPPORTED
854 static void
855 gp_bgr8(Pixel *p, png_const_voidp pb)
856 {
857 png_const_bytep pp = voidcast(png_const_bytep, pb);
858
859 p->r = pp[2];
860 p->g = pp[1];
861 p->b = pp[0];
862 p->a = 255;
863 }
864 #endif
865
866 static void
867 gp_rgba8(Pixel *p, png_const_voidp pb)
868 {
869 png_const_bytep pp = voidcast(png_const_bytep, pb);
870
871 p->r = pp[0];
872 p->g = pp[1];
873 p->b = pp[2];
874 p->a = pp[3];
875 }
876
877 #ifdef PNG_FORMAT_BGR_SUPPORTED
878 static void
879 gp_bgra8(Pixel *p, png_const_voidp pb)
880 {
881 png_const_bytep pp = voidcast(png_const_bytep, pb);
882
883 p->r = pp[2];
884 p->g = pp[1];
885 p->b = pp[0];
886 p->a = pp[3];
887 }
888 #endif
889
890 #ifdef PNG_FORMAT_AFIRST_SUPPORTED
891 static void
892 gp_argb8(Pixel *p, png_const_voidp pb)
893 {
894 png_const_bytep pp = voidcast(png_const_bytep, pb);
895
896 p->r = pp[1];
897 p->g = pp[2];
898 p->b = pp[3];
899 p->a = pp[0];
900 }
901 #endif
902
903 #if defined(PNG_FORMAT_AFIRST_SUPPORTED) && defined(PNG_FORMAT_BGR_SUPPORTED)
904 static void
905 gp_abgr8(Pixel *p, png_const_voidp pb)
906 {
907 png_const_bytep pp = voidcast(png_const_bytep, pb);
908
909 p->r = pp[3];
910 p->g = pp[2];
911 p->b = pp[1];
912 p->a = pp[0];
913 }
914 #endif
915
916 static void
917 gp_g16(Pixel *p, png_const_voidp pb)
918 {
919 png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
920
921 p->r = p->g = p->b = pp[0];
922 p->a = 65535;
923 }
924
925 static void
926 gp_ga16(Pixel *p, png_const_voidp pb)
927 {
928 png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
929
930 p->r = p->g = p->b = pp[0];
931 p->a = pp[1];
932 }
933
934 #ifdef PNG_FORMAT_AFIRST_SUPPORTED
935 static void
936 gp_ag16(Pixel *p, png_const_voidp pb)
937 {
938 png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
939
940 p->r = p->g = p->b = pp[1];
941 p->a = pp[0];
942 }
943 #endif
944
945 static void
946 gp_rgb16(Pixel *p, png_const_voidp pb)
947 {
948 png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
949
950 p->r = pp[0];
951 p->g = pp[1];
952 p->b = pp[2];
953 p->a = 65535;
954 }
955
956 #ifdef PNG_FORMAT_BGR_SUPPORTED
957 static void
958 gp_bgr16(Pixel *p, png_const_voidp pb)
959 {
960 png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
961
962 p->r = pp[2];
963 p->g = pp[1];
964 p->b = pp[0];
965 p->a = 65535;
966 }
967 #endif
968
969 static void
970 gp_rgba16(Pixel *p, png_const_voidp pb)
971 {
972 png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
973
974 p->r = pp[0];
975 p->g = pp[1];
976 p->b = pp[2];
977 p->a = pp[3];
978 }
979
980 #ifdef PNG_FORMAT_BGR_SUPPORTED
981 static void
982 gp_bgra16(Pixel *p, png_const_voidp pb)
983 {
984 png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
985
986 p->r = pp[2];
987 p->g = pp[1];
988 p->b = pp[0];
989 p->a = pp[3];
990 }
991 #endif
992
993 #ifdef PNG_FORMAT_AFIRST_SUPPORTED
994 static void
995 gp_argb16(Pixel *p, png_const_voidp pb)
996 {
997 png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
998
999 p->r = pp[1];
1000 p->g = pp[2];
1001 p->b = pp[3];
1002 p->a = pp[0];
1003 }
1004 #endif
1005
1006 #if defined(PNG_FORMAT_AFIRST_SUPPORTED) && defined(PNG_FORMAT_BGR_SUPPORTED)
1007 static void
1008 gp_abgr16(Pixel *p, png_const_voidp pb)
1009 {
1010 png_const_uint_16p pp = voidcast(png_const_uint_16p, pb);
1011
1012 p->r = pp[3];
1013 p->g = pp[2];
1014 p->b = pp[1];
1015 p->a = pp[0];
1016 }
1017 #endif
1018
1019 /* Given a format, return the correct one of the above functions. */
1020 static void (*
1021 get_pixel(png_uint_32 format))(Pixel *p, png_const_voidp pb)
1022 {
1023 /* The color-map flag is irrelevant here - the caller of the function
1024 * returned must either pass the buffer or, for a color-mapped image, the
1025 * correct entry in the color-map.
1026 */
1027 if (format & PNG_FORMAT_FLAG_LINEAR)
1028 {
1029 if (format & PNG_FORMAT_FLAG_COLOR)
1030 {
1031 # ifdef PNG_FORMAT_BGR_SUPPORTED
1032 if (format & PNG_FORMAT_FLAG_BGR)
1033 {
1034 if (format & PNG_FORMAT_FLAG_ALPHA)
1035 {
1036 # ifdef PNG_FORMAT_AFIRST_SUPPORTED
1037 if (format & PNG_FORMAT_FLAG_AFIRST)
1038 return gp_abgr16;
1039
1040 else
1041 # endif
1042 return gp_bgra16;
1043 }
1044
1045 else
1046 return gp_bgr16;
1047 }
1048
1049 else
1050 # endif
1051 {
1052 if (format & PNG_FORMAT_FLAG_ALPHA)
1053 {
1054 # ifdef PNG_FORMAT_AFIRST_SUPPORTED
1055 if (format & PNG_FORMAT_FLAG_AFIRST)
1056 return gp_argb16;
1057
1058 else
1059 # endif
1060 return gp_rgba16;
1061 }
1062
1063 else
1064 return gp_rgb16;
1065 }
1066 }
1067
1068 else
1069 {
1070 if (format & PNG_FORMAT_FLAG_ALPHA)
1071 {
1072 # ifdef PNG_FORMAT_AFIRST_SUPPORTED
1073 if (format & PNG_FORMAT_FLAG_AFIRST)
1074 return gp_ag16;
1075
1076 else
1077 # endif
1078 return gp_ga16;
1079 }
1080
1081 else
1082 return gp_g16;
1083 }
1084 }
1085
1086 else
1087 {
1088 if (format & PNG_FORMAT_FLAG_COLOR)
1089 {
1090 # ifdef PNG_FORMAT_BGR_SUPPORTED
1091 if (format & PNG_FORMAT_FLAG_BGR)
1092 {
1093 if (format & PNG_FORMAT_FLAG_ALPHA)
1094 {
1095 # ifdef PNG_FORMAT_AFIRST_SUPPORTED
1096 if (format & PNG_FORMAT_FLAG_AFIRST)
1097 return gp_abgr8;
1098
1099 else
1100 # endif
1101 return gp_bgra8;
1102 }
1103
1104 else
1105 return gp_bgr8;
1106 }
1107
1108 else
1109 # endif
1110 {
1111 if (format & PNG_FORMAT_FLAG_ALPHA)
1112 {
1113 # ifdef PNG_FORMAT_AFIRST_SUPPORTED
1114 if (format & PNG_FORMAT_FLAG_AFIRST)
1115 return gp_argb8;
1116
1117 else
1118 # endif
1119 return gp_rgba8;
1120 }
1121
1122 else
1123 return gp_rgb8;
1124 }
1125 }
1126
1127 else
1128 {
1129 if (format & PNG_FORMAT_FLAG_ALPHA)
1130 {
1131 # ifdef PNG_FORMAT_AFIRST_SUPPORTED
1132 if (format & PNG_FORMAT_FLAG_AFIRST)
1133 return gp_ag8;
1134
1135 else
1136 # endif
1137 return gp_ga8;
1138 }
1139
1140 else
1141 return gp_g8;
1142 }
1143 }
1144 }
1145
1146 /* Conversion between pixel formats. The code above effectively eliminates the
1147 * component ordering changes leaving three basic changes:
1148 *
1149 * 1) Remove an alpha channel by pre-multiplication or compositing on a
1150 * background color. (Adding an alpha channel is a no-op.)
1151 *
1152 * 2) Remove color by mapping to grayscale. (Grayscale to color is a no-op.)
1153 *
1154 * 3) Convert between 8-bit and 16-bit components. (Both directions are
1155 * relevant.)
1156 *
1157 * This gives the following base format conversion matrix:
1158 *
1159 * OUT: ----- 8-bit ----- ----- 16-bit -----
1160 * IN G GA RGB RGBA G GA RGB RGBA
1161 * 8 G . . . . lin lin lin lin
1162 * 8 GA bckg . bckc . pre' pre pre' pre
1163 * 8 RGB g8 g8 . . glin glin lin lin
1164 * 8 RGBA g8b g8 bckc . gpr' gpre pre' pre
1165 * 16 G sRGB sRGB sRGB sRGB . . . .
1166 * 16 GA b16g unpg b16c unpc A . A .
1167 * 16 RGB sG sG sRGB sRGB g16 g16 . .
1168 * 16 RGBA gb16 sGp cb16 sCp g16 g16' A .
1169 *
1170 * 8-bit to 8-bit:
1171 * bckg: composite on gray background
1172 * bckc: composite on color background
1173 * g8: convert sRGB components to sRGB grayscale
1174 * g8b: convert sRGB components to grayscale and composite on gray background
1175 *
1176 * 8-bit to 16-bit:
1177 * lin: make sRGB components linear, alpha := 65535
1178 * pre: make sRGB components linear and premultiply by alpha (scale alpha)
1179 * pre': as 'pre' but alpha := 65535
1180 * glin: make sRGB components linear, convert to grayscale, alpha := 65535
1181 * gpre: make sRGB components grayscale and linear and premultiply by alpha
1182 * gpr': as 'gpre' but alpha := 65535
1183 *
1184 * 16-bit to 8-bit:
1185 * sRGB: convert linear components to sRGB, alpha := 255
1186 * unpg: unpremultiply gray component and convert to sRGB (scale alpha)
1187 * unpc: unpremultiply color components and convert to sRGB (scale alpha)
1188 * b16g: composite linear onto gray background and convert the result to sRGB
1189 * b16c: composite linear onto color background and convert the result to sRGB
1190 * sG: convert linear RGB to sRGB grayscale
1191 * sGp: unpremultiply RGB then convert to sRGB grayscale
1192 * sCp: unpremultiply RGB then convert to sRGB
1193 * gb16: composite linear onto background and convert to sRGB grayscale
1194 * (order doesn't matter, the composite and grayscale operations permute)
1195 * cb16: composite linear onto background and convert to sRGB
1196 *
1197 * 16-bit to 16-bit:
1198 * A: set alpha to 65535
1199 * g16: convert linear RGB to linear grayscale (alpha := 65535)
1200 * g16': as 'g16' but alpha is unchanged
1201 */
1202 /* Simple copy: */
1203 static void
1204 gpc_noop(Pixel *out, const Pixel *in, const Background *back)
1205 {
1206 (void)back;
1207 out->r = in->r;
1208 out->g = in->g;
1209 out->b = in->b;
1210 out->a = in->a;
1211 }
1212
1213 #if ALLOW_UNUSED_GPC
1214 static void
1215 gpc_nop8(Pixel *out, const Pixel *in, const Background *back)
1216 {
1217 (void)back;
1218 if (in->a == 0)
1219 out->r = out->g = out->b = 255;
1220
1221 else
1222 {
1223 out->r = in->r;
1224 out->g = in->g;
1225 out->b = in->b;
1226 }
1227
1228 out->a = in->a;
1229 }
1230 #endif
1231
1232 #if ALLOW_UNUSED_GPC
1233 static void
1234 gpc_nop6(Pixel *out, const Pixel *in, const Background *back)
1235 {
1236 (void)back;
1237 if (in->a == 0)
1238 out->r = out->g = out->b = 65535;
1239
1240 else
1241 {
1242 out->r = in->r;
1243 out->g = in->g;
1244 out->b = in->b;
1245 }
1246
1247 out->a = in->a;
1248 }
1249 #endif
1250
1251 /* 8-bit to 8-bit conversions */
1252 /* bckg: composite on gray background */
1253 static void
1254 gpc_bckg(Pixel *out, const Pixel *in, const Background *back)
1255 {
1256 if (in->a <= 0)
1257 out->r = out->g = out->b = back->ig;
1258
1259 else if (in->a >= 255)
1260 out->r = out->g = out->b = in->g;
1261
1262 else
1263 {
1264 double a = in->a / 255.;
1265
1266 out->r = out->g = out->b = sRGB(sRGB_to_d[in->g] * a + back->dg * (1-a));
1267 }
1268
1269 out->a = 255;
1270 }
1271
1272 /* bckc: composite on color background */
1273 static void
1274 gpc_bckc(Pixel *out, const Pixel *in, const Background *back)
1275 {
1276 if (in->a <= 0)
1277 {
1278 out->r = back->ir;
1279 out->g = back->ig;
1280 out->b = back->ib;
1281 }
1282
1283 else if (in->a >= 255)
1284 {
1285 out->r = in->r;
1286 out->g = in->g;
1287 out->b = in->b;
1288 }
1289
1290 else
1291 {
1292 double a = in->a / 255.;
1293
1294 out->r = sRGB(sRGB_to_d[in->r] * a + back->dr * (1-a));
1295 out->g = sRGB(sRGB_to_d[in->g] * a + back->dg * (1-a));
1296 out->b = sRGB(sRGB_to_d[in->b] * a + back->db * (1-a));
1297 }
1298
1299 out->a = 255;
1300 }
1301
1302 /* g8: convert sRGB components to sRGB grayscale */
1303 static void
1304 gpc_g8(Pixel *out, const Pixel *in, const Background *back)
1305 {
1306 (void)back;
1307
1308 if (in->r == in->g && in->g == in->b)
1309 out->r = out->g = out->b = in->g;
1310
1311 else
1312 out->r = out->g = out->b =
1313 sRGB(YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
1314
1315 out->a = in->a;
1316 }
1317
1318 /* g8b: convert sRGB components to grayscale and composite on gray background */
1319 static void
1320 gpc_g8b(Pixel *out, const Pixel *in, const Background *back)
1321 {
1322 if (in->a <= 0)
1323 out->r = out->g = out->b = back->ig;
1324
1325 else if (in->a >= 255)
1326 {
1327 if (in->r == in->g && in->g == in->b)
1328 out->r = out->g = out->b = in->g;
1329
1330 else
1331 out->r = out->g = out->b = sRGB(YfromRGB(
1332 sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
1333 }
1334
1335 else
1336 {
1337 double a = in->a/255.;
1338
1339 out->r = out->g = out->b = sRGB(a * YfromRGB(sRGB_to_d[in->r],
1340 sRGB_to_d[in->g], sRGB_to_d[in->b]) + back->dg * (1-a));
1341 }
1342
1343 out->a = 255;
1344 }
1345
1346 /* 8-bit to 16-bit conversions */
1347 /* lin: make sRGB components linear, alpha := 65535 */
1348 static void
1349 gpc_lin(Pixel *out, const Pixel *in, const Background *back)
1350 {
1351 (void)back;
1352
1353 out->r = ilinear(in->r);
1354
1355 if (in->g == in->r)
1356 {
1357 out->g = out->r;
1358
1359 if (in->b == in->r)
1360 out->b = out->r;
1361
1362 else
1363 out->b = ilinear(in->b);
1364 }
1365
1366 else
1367 {
1368 out->g = ilinear(in->g);
1369
1370 if (in->b == in->r)
1371 out->b = out->r;
1372
1373 else if (in->b == in->g)
1374 out->b = out->g;
1375
1376 else
1377 out->b = ilinear(in->b);
1378 }
1379
1380 out->a = 65535;
1381 }
1382
1383 /* pre: make sRGB components linear and premultiply by alpha (scale alpha) */
1384 static void
1385 gpc_pre(Pixel *out, const Pixel *in, const Background *back)
1386 {
1387 (void)back;
1388
1389 out->r = ilineara(in->r, in->a);
1390
1391 if (in->g == in->r)
1392 {
1393 out->g = out->r;
1394
1395 if (in->b == in->r)
1396 out->b = out->r;
1397
1398 else
1399 out->b = ilineara(in->b, in->a);
1400 }
1401
1402 else
1403 {
1404 out->g = ilineara(in->g, in->a);
1405
1406 if (in->b == in->r)
1407 out->b = out->r;
1408
1409 else if (in->b == in->g)
1410 out->b = out->g;
1411
1412 else
1413 out->b = ilineara(in->b, in->a);
1414 }
1415
1416 out->a = in->a * 257;
1417 }
1418
1419 /* pre': as 'pre' but alpha := 65535 */
1420 static void
1421 gpc_preq(Pixel *out, const Pixel *in, const Background *back)
1422 {
1423 (void)back;
1424
1425 out->r = ilineara(in->r, in->a);
1426
1427 if (in->g == in->r)
1428 {
1429 out->g = out->r;
1430
1431 if (in->b == in->r)
1432 out->b = out->r;
1433
1434 else
1435 out->b = ilineara(in->b, in->a);
1436 }
1437
1438 else
1439 {
1440 out->g = ilineara(in->g, in->a);
1441
1442 if (in->b == in->r)
1443 out->b = out->r;
1444
1445 else if (in->b == in->g)
1446 out->b = out->g;
1447
1448 else
1449 out->b = ilineara(in->b, in->a);
1450 }
1451
1452 out->a = 65535;
1453 }
1454
1455 /* glin: make sRGB components linear, convert to grayscale, alpha := 65535 */
1456 static void
1457 gpc_glin(Pixel *out, const Pixel *in, const Background *back)
1458 {
1459 (void)back;
1460
1461 if (in->r == in->g && in->g == in->b)
1462 out->r = out->g = out->b = ilinear(in->g);
1463
1464 else
1465 out->r = out->g = out->b = u16d(65535 *
1466 YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
1467
1468 out->a = 65535;
1469 }
1470
1471 /* gpre: make sRGB components grayscale and linear and premultiply by alpha */
1472 static void
1473 gpc_gpre(Pixel *out, const Pixel *in, const Background *back)
1474 {
1475 (void)back;
1476
1477 if (in->r == in->g && in->g == in->b)
1478 out->r = out->g = out->b = ilineara(in->g, in->a);
1479
1480 else
1481 out->r = out->g = out->b = u16d(in->a * 257 *
1482 YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
1483
1484 out->a = 257 * in->a;
1485 }
1486
1487 /* gpr': as 'gpre' but alpha := 65535 */
1488 static void
1489 gpc_gprq(Pixel *out, const Pixel *in, const Background *back)
1490 {
1491 (void)back;
1492
1493 if (in->r == in->g && in->g == in->b)
1494 out->r = out->g = out->b = ilineara(in->g, in->a);
1495
1496 else
1497 out->r = out->g = out->b = u16d(in->a * 257 *
1498 YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b]));
1499
1500 out->a = 65535;
1501 }
1502
1503 /* 8-bit to 16-bit conversions for gAMA 45455 encoded values */
1504 /* Lin: make gAMA 45455 components linear, alpha := 65535 */
1505 static void
1506 gpc_Lin(Pixel *out, const Pixel *in, const Background *back)
1507 {
1508 (void)back;
1509
1510 out->r = ilinear_g22(in->r);
1511
1512 if (in->g == in->r)
1513 {
1514 out->g = out->r;
1515
1516 if (in->b == in->r)
1517 out->b = out->r;
1518
1519 else
1520 out->b = ilinear_g22(in->b);
1521 }
1522
1523 else
1524 {
1525 out->g = ilinear_g22(in->g);
1526
1527 if (in->b == in->r)
1528 out->b = out->r;
1529
1530 else if (in->b == in->g)
1531 out->b = out->g;
1532
1533 else
1534 out->b = ilinear_g22(in->b);
1535 }
1536
1537 out->a = 65535;
1538 }
1539
1540 #if ALLOW_UNUSED_GPC
1541 /* Pre: make gAMA 45455 components linear and premultiply by alpha (scale alpha)
1542 */
1543 static void
1544 gpc_Pre(Pixel *out, const Pixel *in, const Background *back)
1545 {
1546 (void)back;
1547
1548 out->r = ilineara_g22(in->r, in->a);
1549
1550 if (in->g == in->r)
1551 {
1552 out->g = out->r;
1553
1554 if (in->b == in->r)
1555 out->b = out->r;
1556
1557 else
1558 out->b = ilineara_g22(in->b, in->a);
1559 }
1560
1561 else
1562 {
1563 out->g = ilineara_g22(in->g, in->a);
1564
1565 if (in->b == in->r)
1566 out->b = out->r;
1567
1568 else if (in->b == in->g)
1569 out->b = out->g;
1570
1571 else
1572 out->b = ilineara_g22(in->b, in->a);
1573 }
1574
1575 out->a = in->a * 257;
1576 }
1577 #endif
1578
1579 #if ALLOW_UNUSED_GPC
1580 /* Pre': as 'Pre' but alpha := 65535 */
1581 static void
1582 gpc_Preq(Pixel *out, const Pixel *in, const Background *back)
1583 {
1584 (void)back;
1585
1586 out->r = ilineara_g22(in->r, in->a);
1587
1588 if (in->g == in->r)
1589 {
1590 out->g = out->r;
1591
1592 if (in->b == in->r)
1593 out->b = out->r;
1594
1595 else
1596 out->b = ilineara_g22(in->b, in->a);
1597 }
1598
1599 else
1600 {
1601 out->g = ilineara_g22(in->g, in->a);
1602
1603 if (in->b == in->r)
1604 out->b = out->r;
1605
1606 else if (in->b == in->g)
1607 out->b = out->g;
1608
1609 else
1610 out->b = ilineara_g22(in->b, in->a);
1611 }
1612
1613 out->a = 65535;
1614 }
1615 #endif
1616
1617 #if ALLOW_UNUSED_GPC
1618 /* Glin: make gAMA 45455 components linear, convert to grayscale, alpha := 65535
1619 */
1620 static void
1621 gpc_Glin(Pixel *out, const Pixel *in, const Background *back)
1622 {
1623 (void)back;
1624
1625 if (in->r == in->g && in->g == in->b)
1626 out->r = out->g = out->b = ilinear_g22(in->g);
1627
1628 else
1629 out->r = out->g = out->b = u16d(65535 *
1630 YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b]));
1631
1632 out->a = 65535;
1633 }
1634 #endif
1635
1636 #if ALLOW_UNUSED_GPC
1637 /* Gpre: make gAMA 45455 components grayscale and linear and premultiply by
1638 * alpha.
1639 */
1640 static void
1641 gpc_Gpre(Pixel *out, const Pixel *in, const Background *back)
1642 {
1643 (void)back;
1644
1645 if (in->r == in->g && in->g == in->b)
1646 out->r = out->g = out->b = ilineara_g22(in->g, in->a);
1647
1648 else
1649 out->r = out->g = out->b = u16d(in->a * 257 *
1650 YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b]));
1651
1652 out->a = 257 * in->a;
1653 }
1654 #endif
1655
1656 #if ALLOW_UNUSED_GPC
1657 /* Gpr': as 'Gpre' but alpha := 65535 */
1658 static void
1659 gpc_Gprq(Pixel *out, const Pixel *in, const Background *back)
1660 {
1661 (void)back;
1662
1663 if (in->r == in->g && in->g == in->b)
1664 out->r = out->g = out->b = ilineara_g22(in->g, in->a);
1665
1666 else
1667 out->r = out->g = out->b = u16d(in->a * 257 *
1668 YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b]));
1669
1670 out->a = 65535;
1671 }
1672 #endif
1673
1674 /* 16-bit to 8-bit conversions */
1675 /* sRGB: convert linear components to sRGB, alpha := 255 */
1676 static void
1677 gpc_sRGB(Pixel *out, const Pixel *in, const Background *back)
1678 {
1679 (void)back;
1680
1681 out->r = isRGB(in->r);
1682
1683 if (in->g == in->r)
1684 {
1685 out->g = out->r;
1686
1687 if (in->b == in->r)
1688 out->b = out->r;
1689
1690 else
1691 out->b = isRGB(in->b);
1692 }
1693
1694 else
1695 {
1696 out->g = isRGB(in->g);
1697
1698 if (in->b == in->r)
1699 out->b = out->r;
1700
1701 else if (in->b == in->g)
1702 out->b = out->g;
1703
1704 else
1705 out->b = isRGB(in->b);
1706 }
1707
1708 out->a = 255;
1709 }
1710
1711 /* unpg: unpremultiply gray component and convert to sRGB (scale alpha) */
1712 static void
1713 gpc_unpg(Pixel *out, const Pixel *in, const Background *back)
1714 {
1715 (void)back;
1716
1717 if (in->a <= 128)
1718 {
1719 out->r = out->g = out->b = 255;
1720 out->a = 0;
1721 }
1722
1723 else
1724 {
1725 out->r = out->g = out->b = sRGB((double)in->g / in->a);
1726 out->a = u8d(in->a / 257.);
1727 }
1728 }
1729
1730 /* unpc: unpremultiply color components and convert to sRGB (scale alpha) */
1731 static void
1732 gpc_unpc(Pixel *out, const Pixel *in, const Background *back)
1733 {
1734 (void)back;
1735
1736 if (in->a <= 128)
1737 {
1738 out->r = out->g = out->b = 255;
1739 out->a = 0;
1740 }
1741
1742 else
1743 {
1744 out->r = sRGB((double)in->r / in->a);
1745 out->g = sRGB((double)in->g / in->a);
1746 out->b = sRGB((double)in->b / in->a);
1747 out->a = u8d(in->a / 257.);
1748 }
1749 }
1750
1751 /* b16g: composite linear onto gray background and convert the result to sRGB */
1752 static void
1753 gpc_b16g(Pixel *out, const Pixel *in, const Background *back)
1754 {
1755 if (in->a <= 0)
1756 out->r = out->g = out->b = back->ig;
1757
1758 else
1759 {
1760 double a = in->a/65535.;
1761 double a1 = 1-a;
1762
1763 a /= 65535;
1764 out->r = out->g = out->b = sRGB(in->g * a + back->dg * a1);
1765 }
1766
1767 out->a = 255;
1768 }
1769
1770 /* b16c: composite linear onto color background and convert the result to sRGB*/
1771 static void
1772 gpc_b16c(Pixel *out, const Pixel *in, const Background *back)
1773 {
1774 if (in->a <= 0)
1775 {
1776 out->r = back->ir;
1777 out->g = back->ig;
1778 out->b = back->ib;
1779 }
1780
1781 else
1782 {
1783 double a = in->a/65535.;
1784 double a1 = 1-a;
1785
1786 a /= 65535;
1787 out->r = sRGB(in->r * a + back->dr * a1);
1788 out->g = sRGB(in->g * a + back->dg * a1);
1789 out->b = sRGB(in->b * a + back->db * a1);
1790 }
1791
1792 out->a = 255;
1793 }
1794
1795 /* sG: convert linear RGB to sRGB grayscale */
1796 static void
1797 gpc_sG(Pixel *out, const Pixel *in, const Background *back)
1798 {
1799 (void)back;
1800
1801 out->r = out->g = out->b = sRGB(YfromRGBint(in->r, in->g, in->b)/65535);
1802 out->a = 255;
1803 }
1804
1805 /* sGp: unpremultiply RGB then convert to sRGB grayscale */
1806 static void
1807 gpc_sGp(Pixel *out, const Pixel *in, const Background *back)
1808 {
1809 (void)back;
1810
1811 if (in->a <= 128)
1812 {
1813 out->r = out->g = out->b = 255;
1814 out->a = 0;
1815 }
1816
1817 else
1818 {
1819 out->r = out->g = out->b = sRGB(YfromRGBint(in->r, in->g, in->b)/in->a);
1820 out->a = u8d(in->a / 257.);
1821 }
1822 }
1823
1824 /* sCp: unpremultiply RGB then convert to sRGB */
1825 static void
1826 gpc_sCp(Pixel *out, const Pixel *in, const Background *back)
1827 {
1828 (void)back;
1829
1830 if (in->a <= 128)
1831 {
1832 out->r = out->g = out->b = 255;
1833 out->a = 0;
1834 }
1835
1836 else
1837 {
1838 out->r = sRGB((double)in->r / in->a);
1839 out->g = sRGB((double)in->g / in->a);
1840 out->b = sRGB((double)in->b / in->a);
1841 out->a = u8d(in->a / 257.);
1842 }
1843 }
1844
1845 /* gb16: composite linear onto background and convert to sRGB grayscale */
1846 /* (order doesn't matter, the composite and grayscale operations permute) */
1847 static void
1848 gpc_gb16(Pixel *out, const Pixel *in, const Background *back)
1849 {
1850 if (in->a <= 0)
1851 out->r = out->g = out->b = back->ig;
1852
1853 else if (in->a >= 65535)
1854 out->r = out->g = out->b = isRGB(in->g);
1855
1856 else
1857 {
1858 double a = in->a / 65535.;
1859 double a1 = 1-a;
1860
1861 a /= 65535;
1862 out->r = out->g = out->b = sRGB(in->g * a + back->dg * a1);
1863 }
1864
1865 out->a = 255;
1866 }
1867
1868 /* cb16: composite linear onto background and convert to sRGB */
1869 static void
1870 gpc_cb16(Pixel *out, const Pixel *in, const Background *back)
1871 {
1872 if (in->a <= 0)
1873 {
1874 out->r = back->ir;
1875 out->g = back->ig;
1876 out->b = back->ib;
1877 }
1878
1879 else if (in->a >= 65535)
1880 {
1881 out->r = isRGB(in->r);
1882 out->g = isRGB(in->g);
1883 out->b = isRGB(in->b);
1884 }
1885
1886 else
1887 {
1888 double a = in->a / 65535.;
1889 double a1 = 1-a;
1890
1891 a /= 65535;
1892 out->r = sRGB(in->r * a + back->dr * a1);
1893 out->g = sRGB(in->g * a + back->dg * a1);
1894 out->b = sRGB(in->b * a + back->db * a1);
1895 }
1896
1897 out->a = 255;
1898 }
1899
1900 /* 16-bit to 16-bit conversions */
1901 /* A: set alpha to 65535 */
1902 static void
1903 gpc_A(Pixel *out, const Pixel *in, const Background *back)
1904 {
1905 (void)back;
1906 out->r = in->r;
1907 out->g = in->g;
1908 out->b = in->b;
1909 out->a = 65535;
1910 }
1911
1912 /* g16: convert linear RGB to linear grayscale (alpha := 65535) */
1913 static void
1914 gpc_g16(Pixel *out, const Pixel *in, const Background *back)
1915 {
1916 (void)back;
1917 out->r = out->g = out->b = u16d(YfromRGBint(in->r, in->g, in->b));
1918 out->a = 65535;
1919 }
1920
1921 /* g16': as 'g16' but alpha is unchanged */
1922 static void
1923 gpc_g16q(Pixel *out, const Pixel *in, const Background *back)
1924 {
1925 (void)back;
1926 out->r = out->g = out->b = u16d(YfromRGBint(in->r, in->g, in->b));
1927 out->a = in->a;
1928 }
1929
1930 #if ALLOW_UNUSED_GPC
1931 /* Unused functions (to hide them from GCC unused function warnings) */
1932 void (* const gpc_unused[])
1933 (Pixel *out, const Pixel *in, const Background *back) =
1934 {
1935 gpc_Pre, gpc_Preq, gpc_Glin, gpc_Gpre, gpc_Gprq, gpc_nop8, gpc_nop6
1936 };
1937 #endif
1938
1939 /* OUT: ----- 8-bit ----- ----- 16-bit -----
1940 * IN G GA RGB RGBA G GA RGB RGBA
1941 * 8 G . . . . lin lin lin lin
1942 * 8 GA bckg . bckc . pre' pre pre' pre
1943 * 8 RGB g8 g8 . . glin glin lin lin
1944 * 8 RGBA g8b g8 bckc . gpr' gpre pre' pre
1945 * 16 G sRGB sRGB sRGB sRGB . . . .
1946 * 16 GA b16g unpg b16c unpc A . A .
1947 * 16 RGB sG sG sRGB sRGB g16 g16 . .
1948 * 16 RGBA gb16 sGp cb16 sCp g16 g16' A .
1949 *
1950 * The matrix is held in an array indexed thus:
1951 *
1952 * gpc_fn[out_format & BASE_FORMATS][in_format & BASE_FORMATS];
1953 */
1954 /* This will produce a compile time error if the FORMAT_FLAG values don't
1955 * match the above matrix!
1956 */
1957 #if PNG_FORMAT_FLAG_ALPHA == 1 && PNG_FORMAT_FLAG_COLOR == 2 &&\
1958 PNG_FORMAT_FLAG_LINEAR == 4
1959 static void (* const gpc_fn[8/*in*/][8/*out*/])
1960 (Pixel *out, const Pixel *in, const Background *back) =
1961 {
1962 /*out: G-8 GA-8 RGB-8 RGBA-8 G-16 GA-16 RGB-16 RGBA-16 */
1963 {gpc_noop,gpc_noop,gpc_noop,gpc_noop, gpc_Lin, gpc_Lin, gpc_Lin, gpc_Lin },
1964 {gpc_bckg,gpc_noop,gpc_bckc,gpc_noop, gpc_preq,gpc_pre, gpc_preq,gpc_pre },
1965 {gpc_g8, gpc_g8, gpc_noop,gpc_noop, gpc_glin,gpc_glin,gpc_lin, gpc_lin },
1966 {gpc_g8b, gpc_g8, gpc_bckc,gpc_noop, gpc_gprq,gpc_gpre,gpc_preq,gpc_pre },
1967 {gpc_sRGB,gpc_sRGB,gpc_sRGB,gpc_sRGB, gpc_noop,gpc_noop,gpc_noop,gpc_noop},
1968 {gpc_b16g,gpc_unpg,gpc_b16c,gpc_unpc, gpc_A, gpc_noop,gpc_A, gpc_noop},
1969 {gpc_sG, gpc_sG, gpc_sRGB,gpc_sRGB, gpc_g16, gpc_g16, gpc_noop,gpc_noop},
1970 {gpc_gb16,gpc_sGp, gpc_cb16,gpc_sCp, gpc_g16, gpc_g16q,gpc_A, gpc_noop}
1971 };
1972
1973 /* The array is repeated for the cases where both the input and output are color
1974 * mapped because then different algorithms are used.
1975 */
1976 static void (* const gpc_fn_colormapped[8/*in*/][8/*out*/])
1977 (Pixel *out, const Pixel *in, const Background *back) =
1978 {
1979 /*out: G-8 GA-8 RGB-8 RGBA-8 G-16 GA-16 RGB-16 RGBA-16 */
1980 {gpc_noop,gpc_noop,gpc_noop,gpc_noop, gpc_lin, gpc_lin, gpc_lin, gpc_lin },
1981 {gpc_bckg,gpc_noop,gpc_bckc,gpc_noop, gpc_preq,gpc_pre, gpc_preq,gpc_pre },
1982 {gpc_g8, gpc_g8, gpc_noop,gpc_noop, gpc_glin,gpc_glin,gpc_lin, gpc_lin },
1983 {gpc_g8b, gpc_g8, gpc_bckc,gpc_noop, gpc_gprq,gpc_gpre,gpc_preq,gpc_pre },
1984 {gpc_sRGB,gpc_sRGB,gpc_sRGB,gpc_sRGB, gpc_noop,gpc_noop,gpc_noop,gpc_noop},
1985 {gpc_b16g,gpc_unpg,gpc_b16c,gpc_unpc, gpc_A, gpc_noop,gpc_A, gpc_noop},
1986 {gpc_sG, gpc_sG, gpc_sRGB,gpc_sRGB, gpc_g16, gpc_g16, gpc_noop,gpc_noop},
1987 {gpc_gb16,gpc_sGp, gpc_cb16,gpc_sCp, gpc_g16, gpc_g16q,gpc_A, gpc_noop}
1988 };
1989
1990 /* The error arrays record the error in the same matrix; 64 entries, however
1991 * the different algorithms used in libpng for colormap and direct conversions
1992 * mean that four separate matrices are used (for each combination of
1993 * colormapped and direct.)
1994 *
1995 * In some cases the conversion between sRGB formats goes via a linear
1996 * intermediate; an sRGB to linear conversion (as above) is followed by a simple
1997 * linear to sRGB step with no other conversions. This is done by a separate
1998 * error array from an arbitrary 'in' format to one of the four basic outputs
1999 * (since final output is always sRGB not colormapped).
2000 *
2001 * These arrays may be modified if the --accumulate flag is set during the run;
2002 * then instead of logging errors they are simply added in.
2003 *
2004 * The three entries are currently for transparent, partially transparent and
2005 * opaque input pixel values. Notice that alpha should be exact in each case.
2006 *
2007 * Errors in alpha should only occur when converting from a direct format
2008 * to a colormapped format, when alpha is effectively smashed (so large
2009 * errors can occur.) There should be no error in the '0' and 'opaque'
2010 * values. The fourth entry in the array is used for the alpha error (and it
2011 * should always be zero for the 'via linear' case since this is never color
2012 * mapped.)
2013 *
2014 * Mapping to a colormap smashes the colors, it is necessary to have separate
2015 * values for these cases because they are much larger; it is very much
2016 * impossible to obtain a reasonable result, these are held in
2017 * gpc_error_to_colormap.
2018 */
2019 #if PNG_FORMAT_FLAG_COLORMAP == 8 /* extra check also required */
2020 # include "pngstest-errors.h" /* machine generated */
2021 #endif /* COLORMAP flag check */
2022 #endif /* flag checks */
2023
2024 typedef struct
2025 {
2026 /* Basic pixel information: */
2027 Image* in_image; /* Input image */
2028 const Image* out_image; /* Output image */
2029
2030 /* 'background' is the value passed to the gpc_ routines, it may be NULL if
2031 * it should not be used (*this* program has an error if it crashes as a
2032 * result!)
2033 */
2034 Background background_color;
2035 const Background* background;
2036
2037 /* Precalculated values: */
2038 int in_opaque; /* Value of input alpha that is opaque */
2039 int is_palette; /* Sample values come from the palette */
2040 int accumulate; /* Accumulate component errors (don't log) */
2041 int output_8bit; /* Output is 8-bit (else 16-bit) */
2042
2043 void (*in_gp)(Pixel*, png_const_voidp);
2044 void (*out_gp)(Pixel*, png_const_voidp);
2045
2046 void (*transform)(Pixel *out, const Pixel *in, const Background *back);
2047 /* A function to perform the required transform */
2048
2049 void (*from_linear)(Pixel *out, const Pixel *in, const Background *back);
2050 /* For 'via_linear' transforms the final, from linear, step, else NULL */
2051
2052 png_uint_16 error[4];
2053 /* Three error values for transparent, partially transparent and opaque
2054 * input pixels (in turn).
2055 */
2056
2057 png_uint_16 *error_ptr;
2058 /* Where these are stored in the static array (for 'accumulate') */
2059 }
2060 Transform;
2061
2062 /* Return a 'transform' as above for the given format conversion. */
2063 static void
2064 transform_from_formats(Transform *result, Image *in_image,
2065 const Image *out_image, png_const_colorp background, int via_linear)
2066 {
2067 png_uint_32 in_format, out_format;
2068 png_uint_32 in_base, out_base;
2069
2070 memset(result, 0, sizeof *result);
2071
2072 /* Store the original images for error messages */
2073 result->in_image = in_image;
2074 result->out_image = out_image;
2075
2076 in_format = in_image->image.format;
2077 out_format = out_image->image.format;
2078
2079 if (in_format & PNG_FORMAT_FLAG_LINEAR)
2080 result->in_opaque = 65535;
2081 else
2082 result->in_opaque = 255;
2083
2084 result->output_8bit = (out_format & PNG_FORMAT_FLAG_LINEAR) == 0;
2085
2086 result->is_palette = 0; /* set by caller if required */
2087 result->accumulate = (in_image->opts & ACCUMULATE) != 0;
2088
2089 /* The loaders (which need the ordering information) */
2090 result->in_gp = get_pixel(in_format);
2091 result->out_gp = get_pixel(out_format);
2092
2093 /* Remove the ordering information: */
2094 in_format &= BASE_FORMATS | PNG_FORMAT_FLAG_COLORMAP;
2095 in_base = in_format & BASE_FORMATS;
2096 out_format &= BASE_FORMATS | PNG_FORMAT_FLAG_COLORMAP;
2097 out_base = out_format & BASE_FORMATS;
2098
2099 if (via_linear)
2100 {
2101 /* Check for an error in this program: */
2102 if (out_format & (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLORMAP))
2103 {
2104 fprintf(stderr, "internal transform via linear error 0x%x->0x%x\n",
2105 in_format, out_format);
2106 exit(1);
2107 }
2108
2109 result->transform = gpc_fn[in_base][out_base | PNG_FORMAT_FLAG_LINEAR];
2110 result->from_linear = gpc_fn[out_base | PNG_FORMAT_FLAG_LINEAR][out_base];
2111 result->error_ptr = gpc_error_via_linear[in_format][out_format];
2112 }
2113
2114 else if (~in_format & out_format & PNG_FORMAT_FLAG_COLORMAP)
2115 {
2116 /* The input is not colormapped but the output is, the errors will
2117 * typically be large (only the grayscale-no-alpha case permits preserving
2118 * even 8-bit values.)
2119 */
2120 result->transform = gpc_fn[in_base][out_base];
2121 result->from_linear = NULL;
2122 result->error_ptr = gpc_error_to_colormap[in_base][out_base];
2123 }
2124
2125 else
2126 {
2127 /* The caller handles the colormap->pixel value conversion, so the
2128 * transform function just gets a pixel value, however because libpng
2129 * currently contains a different implementation for mapping a colormap if
2130 * both input and output are colormapped we need different conversion
2131 * functions to deal with errors in the libpng implementation.
2132 */
2133 if (in_format & out_format & PNG_FORMAT_FLAG_COLORMAP)
2134 result->transform = gpc_fn_colormapped[in_base][out_base];
2135 else
2136 result->transform = gpc_fn[in_base][out_base];
2137 result->from_linear = NULL;
2138 result->error_ptr = gpc_error[in_format][out_format];
2139 }
2140
2141 /* Follow the libpng simplified API rules to work out what to pass to the gpc
2142 * routines as a background value, if one is not required pass NULL so that
2143 * this program crashes in the even of a programming error.
2144 */
2145 result->background = NULL; /* default: not required */
2146
2147 /* Rule 1: background only need be supplied if alpha is to be removed */
2148 if (in_format & ~out_format & PNG_FORMAT_FLAG_ALPHA)
2149 {
2150 /* The input value is 'NULL' to use the background and (otherwise) an sRGB
2151 * background color (to use a solid color). The code above uses a fixed
2152 * byte value, BUFFER_INIT8, for buffer even for 16-bit output. For
2153 * linear (16-bit) output the sRGB background color is ignored; the
2154 * composition is always on the background (so BUFFER_INIT8 * 257), except
2155 * that for the colormap (i.e. linear colormapped output) black is used.
2156 */
2157 result->background = &result->background_color;
2158
2159 if (out_format & PNG_FORMAT_FLAG_LINEAR || via_linear)
2160 {
2161 if (out_format & PNG_FORMAT_FLAG_COLORMAP)
2162 {
2163 result->background_color.ir =
2164 result->background_color.ig =
2165 result->background_color.ib = 0;
2166 result->background_color.dr =
2167 result->background_color.dg =
2168 result->background_color.db = 0;
2169 }
2170
2171 else
2172 {
2173 result->background_color.ir =
2174 result->background_color.ig =
2175 result->background_color.ib = BUFFER_INIT8 * 257;
2176 result->background_color.dr =
2177 result->background_color.dg =
2178 result->background_color.db = 0;
2179 }
2180 }
2181
2182 else /* sRGB output */
2183 {
2184 if (background != NULL)
2185 {
2186 if (out_format & PNG_FORMAT_FLAG_COLOR)
2187 {
2188 result->background_color.ir = background->red;
2189 result->background_color.ig = background->green;
2190 result->background_color.ib = background->blue;
2191 /* TODO: sometimes libpng uses the power law conversion here, how
2192 * to handle this?
2193 */
2194 result->background_color.dr = sRGB_to_d[background->red];
2195 result->background_color.dg = sRGB_to_d[background->green];
2196 result->background_color.db = sRGB_to_d[background->blue];
2197 }
2198
2199 else /* grayscale: libpng only looks at 'g' */
2200 {
2201 result->background_color.ir =
2202 result->background_color.ig =
2203 result->background_color.ib = background->green;
2204 /* TODO: sometimes libpng uses the power law conversion here, how
2205 * to handle this?
2206 */
2207 result->background_color.dr =
2208 result->background_color.dg =
2209 result->background_color.db = sRGB_to_d[background->green];
2210 }
2211 }
2212
2213 else if ((out_format & PNG_FORMAT_FLAG_COLORMAP) == 0)
2214 {
2215 result->background_color.ir =
2216 result->background_color.ig =
2217 result->background_color.ib = BUFFER_INIT8;
2218 /* TODO: sometimes libpng uses the power law conversion here, how
2219 * to handle this?
2220 */
2221 result->background_color.dr =
2222 result->background_color.dg =
2223 result->background_color.db = sRGB_to_d[BUFFER_INIT8];
2224 }
2225
2226 /* Else the output is colormapped and a background color must be
2227 * provided; if pngstest crashes then that is a bug in this program
2228 * (though libpng should png_error as well.)
2229 */
2230 else
2231 result->background = NULL;
2232 }
2233 }
2234
2235 if (result->background == NULL)
2236 {
2237 result->background_color.ir =
2238 result->background_color.ig =
2239 result->background_color.ib = -1; /* not used */
2240 result->background_color.dr =
2241 result->background_color.dg =
2242 result->background_color.db = 1E30; /* not used */
2243 }
2244
2245
2246 /* Copy the error values into the Transform: */
2247 result->error[0] = result->error_ptr[0];
2248 result->error[1] = result->error_ptr[1];
2249 result->error[2] = result->error_ptr[2];
2250 result->error[3] = result->error_ptr[3];
2251 }
2252
2253
2254 /* Compare two pixels.
2255 *
2256 * OLD error values:
2257 static int error_to_linear = 811; * by experiment *
2258 static int error_to_linear_grayscale = 424; * by experiment *
2259 static int error_to_sRGB = 6; * by experiment *
2260 static int error_to_sRGB_grayscale = 17; * libpng error by calculation +
2261 2 by experiment *
2262 static int error_in_compose = 2; * by experiment *
2263 static int error_in_premultiply = 1;
2264 *
2265 * The following is *just* the result of a round trip from 8-bit sRGB to linear
2266 * then back to 8-bit sRGB when it is done by libpng. There are two problems:
2267 *
2268 * 1) libpng currently uses a 2.2 power law with no linear segment, this results
2269 * in instability in the low values and even with 16-bit precision sRGB(1) ends
2270 * up mapping to sRGB(0) as a result of rounding in the 16-bit representation.
2271 * This gives an error of 1 in the handling of value 1 only.
2272 *
2273 * 2) libpng currently uses an intermediate 8-bit linear value in gamma
2274 * correction of 8-bit values. This results in many more errors, the worse of
2275 * which is mapping sRGB(14) to sRGB(0).
2276 *
2277 * The general 'error_via_linear' is more complex because of pre-multiplication,
2278 * this compounds the 8-bit errors according to the alpha value of the pixel.
2279 * As a result 256 values are pre-calculated for error_via_linear.
2280 */
2281 #if 0
2282 static int error_in_libpng_gamma;
2283 static int error_via_linear[256]; /* Indexed by 8-bit alpha */
2284
2285 static void
2286 init_error_via_linear(void)
2287 {
2288 int alpha;
2289
2290 error_via_linear[0] = 255; /* transparent pixel */
2291
2292 for (alpha=1; alpha<=255; ++alpha)
2293 {
2294 /* 16-bit values less than 128.5 get rounded to 8-bit 0 and so the worst
2295 * case error arises with 16-bit 128.5, work out what sRGB
2296 * (non-associated) value generates 128.5; any value less than this is
2297 * going to map to 0, so the worst error is floor(value).
2298 *
2299 * Note that errors are considerably higher (more than a factor of 2)
2300 * because libpng uses a simple power law for sRGB data at present.
2301 *
2302 * Add .1 for arithmetic errors inside libpng.
2303 */
2304 double v = floor(255*pow(.5/*(128.5 * 255 / 65535)*/ / alpha, 1/2.2)+.1);
2305
2306 error_via_linear[alpha] = (int)v;
2307 }
2308
2309 /* This is actually 14.99, but, despite the closeness to 15, 14 seems to work
2310 * ok in this case.
2311 */
2312 error_in_libpng_gamma = 14;
2313 }
2314 #endif
2315
2316 static void
2317 print_pixel(char string[64], const Pixel *pixel, png_uint_32 format)
2318 {
2319 switch (format & (PNG_FORMAT_FLAG_ALPHA|PNG_FORMAT_FLAG_COLOR))
2320 {
2321 case 0:
2322 sprintf(string, "%s(%d)", format_names[format], pixel->g);
2323 break;
2324
2325 case PNG_FORMAT_FLAG_ALPHA:
2326 sprintf(string, "%s(%d,%d)", format_names[format], pixel->g,
2327 pixel->a);
2328 break;
2329
2330 case PNG_FORMAT_FLAG_COLOR:
2331 sprintf(string, "%s(%d,%d,%d)", format_names[format],
2332 pixel->r, pixel->g, pixel->b);
2333 break;
2334
2335 case PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA:
2336 sprintf(string, "%s(%d,%d,%d,%d)", format_names[format],
2337 pixel->r, pixel->g, pixel->b, pixel->a);
2338 break;
2339
2340 default:
2341 sprintf(string, "invalid-format");
2342 break;
2343 }
2344 }
2345
2346 static int
2347 logpixel(const Transform *transform, png_uint_32 x, png_uint_32 y,
2348 const Pixel *in, const Pixel *calc, const Pixel *out, const char *reason)
2349 {
2350 png_uint_32 in_format = transform->in_image->image.format;
2351 png_uint_32 out_format = transform->out_image->image.format;
2352
2353 png_uint_32 back_format = out_format & ~PNG_FORMAT_FLAG_ALPHA;
2354 const char *via_linear = "";
2355
2356 char pixel_in[64], pixel_calc[64], pixel_out[64], pixel_loc[64];
2357 char background_info[100];
2358
2359 print_pixel(pixel_in, in, in_format);
2360 print_pixel(pixel_calc, calc, out_format);
2361 print_pixel(pixel_out, out, out_format);
2362
2363 if (transform->is_palette)
2364 sprintf(pixel_loc, "palette: %lu", (unsigned long)y);
2365 else
2366 sprintf(pixel_loc, "%lu,%lu", (unsigned long)x, (unsigned long)y);
2367
2368 if (transform->from_linear != NULL)
2369 {
2370 via_linear = " (via linear)";
2371 /* And as a result the *read* format which did any background processing
2372 * was itself linear, so the background color information is also
2373 * linear.
2374 */
2375 back_format |= PNG_FORMAT_FLAG_LINEAR;
2376 }
2377
2378 if (transform->background != NULL)
2379 {
2380 Pixel back;
2381 char pixel_back[64];
2382
2383 back.r = transform->background->ir;
2384 back.g = transform->background->ig;
2385 back.b = transform->background->ib;
2386 back.a = -1; /* not used */
2387
2388 print_pixel(pixel_back, &back, back_format);
2389 sprintf(background_info, " on background %s", pixel_back);
2390 }
2391
2392 else
2393 background_info[0] = 0;
2394
2395 if (transform->in_image->file_name != transform->out_image->file_name)
2396 {
2397 char error_buffer[512];
2398 sprintf(error_buffer,
2399 "(%s) %s error%s:\n %s%s ->\n %s\n not: %s.\n"
2400 "Use --preserve and examine: ", pixel_loc, reason, via_linear,
2401 pixel_in, background_info, pixel_out, pixel_calc);
2402 return logerror(transform->in_image, transform->in_image->file_name,
2403 error_buffer, transform->out_image->file_name);
2404 }
2405
2406 else
2407 {
2408 char error_buffer[512];
2409 sprintf(error_buffer,
2410 "(%s) %s error%s:\n %s%s ->\n %s\n not: %s.\n"
2411 " The error happened when reading the original file with this format.",
2412 pixel_loc, reason, via_linear, pixel_in, background_info, pixel_out,
2413 pixel_calc);
2414 return logerror(transform->in_image, transform->in_image->file_name,
2415 error_buffer, "");
2416 }
2417 }
2418
2419 static int
2420 cmppixel(Transform *transform, png_const_voidp in, png_const_voidp out,
2421 png_uint_32 x, png_uint_32 y/*or palette index*/)
2422 {
2423 int maxerr;
2424 png_const_charp errmsg;
2425 Pixel pixel_in, pixel_calc, pixel_out;
2426
2427 transform->in_gp(&pixel_in, in);
2428
2429 if (transform->from_linear == NULL)
2430 transform->transform(&pixel_calc, &pixel_in, transform->background);
2431
2432 else
2433 {
2434 transform->transform(&pixel_out, &pixel_in, transform->background);
2435 transform->from_linear(&pixel_calc, &pixel_out, NULL);
2436 }
2437
2438 transform->out_gp(&pixel_out, out);
2439
2440 /* Eliminate the case where the input and output values match exactly. */
2441 if (pixel_calc.a == pixel_out.a && pixel_calc.r == pixel_out.r &&
2442 pixel_calc.g == pixel_out.g && pixel_calc.b == pixel_out.b)
2443 return 1;
2444
2445 /* Eliminate the case where the output pixel is transparent and the output
2446 * is 8-bit - any component values are valid. Don't check the input alpha
2447 * here to also skip the 16-bit small alpha cases.
2448 */
2449 if (transform->output_8bit && pixel_calc.a == 0 && pixel_out.a == 0)
2450 return 1;
2451
2452 /* Check for alpha errors first; an alpha error can damage the components too
2453 * so avoid spurious checks on components if one is found.
2454 */
2455 errmsg = NULL;
2456 {
2457 int err_a = abs(pixel_calc.a-pixel_out.a);
2458
2459 if (err_a > transform->error[3])
2460 {
2461 /* If accumulating check the components too */
2462 if (transform->accumulate)
2463 transform->error[3] = (png_uint_16)err_a;
2464
2465 else
2466 errmsg = "alpha";
2467 }
2468 }
2469
2470 /* Now if *either* of the output alphas are 0 but alpha is within tolerance
2471 * eliminate the 8-bit component comparison.
2472 */
2473 if (errmsg == NULL && transform->output_8bit &&
2474 (pixel_calc.a == 0 || pixel_out.a == 0))
2475 return 1;
2476
2477 if (errmsg == NULL) /* else just signal an alpha error */
2478 {
2479 int err_r = abs(pixel_calc.r - pixel_out.r);
2480 int err_g = abs(pixel_calc.g - pixel_out.g);
2481 int err_b = abs(pixel_calc.b - pixel_out.b);
2482 int limit;
2483
2484 if ((err_r | err_g | err_b) == 0)
2485 return 1; /* exact match */
2486
2487 /* Mismatch on a component, check the input alpha */
2488 if (pixel_in.a >= transform->in_opaque)
2489 {
2490 errmsg = "opaque component";
2491 limit = 2; /* opaque */
2492 }
2493
2494 else if (pixel_in.a > 0)
2495 {
2496 errmsg = "alpha component";
2497 limit = 1; /* partially transparent */
2498 }
2499
2500 else
2501 {
2502 errmsg = "transparent component (background)";
2503 limit = 0; /* transparent */
2504 }
2505
2506 maxerr = err_r;
2507 if (maxerr < err_g) maxerr = err_g;
2508 if (maxerr < err_b) maxerr = err_b;
2509
2510 if (maxerr <= transform->error[limit])
2511 return 1; /* within the error limits */
2512
2513 /* Handle a component mis-match; log it, just return an error code, or
2514 * accumulate it.
2515 */
2516 if (transform->accumulate)
2517 {
2518 transform->error[limit] = (png_uint_16)maxerr;
2519 return 1; /* to cause the caller to keep going */
2520 }
2521 }
2522
2523 /* Failure to match and not accumulating, so the error must be logged. */
2524 return logpixel(transform, x, y, &pixel_in, &pixel_calc, &pixel_out, errmsg);
2525 }
2526
2527 static png_byte
2528 component_loc(png_byte loc[4], png_uint_32 format)
2529 {
2530 /* Given a format return the number of channels and the location of
2531 * each channel.
2532 *
2533 * The mask 'loc' contains the component offset of the channels in the
2534 * following order. Note that if 'format' is grayscale the entries 1-3 must
2535 * all contain the location of the gray channel.
2536 *
2537 * 0: alpha
2538 * 1: red or gray
2539 * 2: green or gray
2540 * 3: blue or gray
2541 */
2542 png_byte channels;
2543
2544 if (format & PNG_FORMAT_FLAG_COLOR)
2545 {
2546 channels = 3;
2547
2548 loc[2] = 1;
2549
2550 # ifdef PNG_FORMAT_BGR_SUPPORTED
2551 if (format & PNG_FORMAT_FLAG_BGR)
2552 {
2553 loc[1] = 2;
2554 loc[3] = 0;
2555 }
2556
2557 else
2558 # endif
2559 {
2560 loc[1] = 0;
2561 loc[3] = 2;
2562 }
2563 }
2564
2565 else
2566 {
2567 channels = 1;
2568 loc[1] = loc[2] = loc[3] = 0;
2569 }
2570
2571 if (format & PNG_FORMAT_FLAG_ALPHA)
2572 {
2573 # ifdef PNG_FORMAT_AFIRST_SUPPORTED
2574 if (format & PNG_FORMAT_FLAG_AFIRST)
2575 {
2576 loc[0] = 0;
2577 ++loc[1];
2578 ++loc[2];
2579 ++loc[3];
2580 }
2581
2582 else
2583 # endif
2584 loc[0] = channels;
2585
2586 ++channels;
2587 }
2588
2589 else
2590 loc[0] = 4; /* not present */
2591
2592 return channels;
2593 }
2594
2595 /* Compare two images, the original 'a', which was written out then read back in
2596 * to * give image 'b'. The formats may have been changed.
2597 */
2598 static int
2599 compare_two_images(Image *a, Image *b, int via_linear,
2600 png_const_colorp background)
2601 {
2602 ptrdiff_t stridea = a->stride;
2603 ptrdiff_t strideb = b->stride;
2604 png_const_bytep rowa = a->buffer+16;
2605 png_const_bytep rowb = b->buffer+16;
2606 png_uint_32 width = a->image.width;
2607 png_uint_32 height = a->image.height;
2608 png_uint_32 formata = a->image.format;
2609 png_uint_32 formatb = b->image.format;
2610 unsigned int a_sample = PNG_IMAGE_SAMPLE_SIZE(formata);
2611 unsigned int b_sample = PNG_IMAGE_SAMPLE_SIZE(formatb);
2612 int alpha_added, alpha_removed;
2613 int bchannels;
2614 png_uint_32 y;
2615 Transform tr;
2616 int btoa[4]={0,0,0,0};
2617
2618 /* This should never happen: */
2619 if (width != b->image.width || height != b->image.height)
2620 return logerror(a, a->file_name, ": width x height changed: ",
2621 b->file_name);
2622
2623 /* Set up the background and the transform */
2624 transform_from_formats(&tr, a, b, background, via_linear);
2625
2626 /* Find the first row and inter-row space. */
2627 if (!(formata & PNG_FORMAT_FLAG_COLORMAP) &&
2628 (formata & PNG_FORMAT_FLAG_LINEAR))
2629 stridea *= 2;
2630
2631 if (!(formatb & PNG_FORMAT_FLAG_COLORMAP) &&
2632 (formatb & PNG_FORMAT_FLAG_LINEAR))
2633 strideb *= 2;
2634
2635 if (stridea < 0) rowa += (height-1) * (-stridea);
2636 if (strideb < 0) rowb += (height-1) * (-strideb);
2637
2638 /* First shortcut the two colormap case by comparing the image data; if it
2639 * matches then we expect the colormaps to match, although this is not
2640 * absolutely necessary for an image match. If the colormaps fail to match
2641 * then there is a problem in libpng.
2642 */
2643 if (formata & formatb & PNG_FORMAT_FLAG_COLORMAP)
2644 {
2645 /* Only check colormap entries that actually exist; */
2646 png_const_bytep ppa, ppb;
2647 int match;
2648 png_byte in_use[256], amax = 0, bmax = 0;
2649
2650 memset(in_use, 0, sizeof in_use);
2651
2652 ppa = rowa;
2653 ppb = rowb;
2654
2655 /* Do this the slow way to accumulate the 'in_use' flags, don't break out
2656 * of the loop until the end; this validates the color-mapped data to
2657 * ensure all pixels are valid color-map indexes.
2658 */
2659 for (y=0, match=1; y<height && match; ++y, ppa += stridea, ppb += strideb)
2660 {
2661 png_uint_32 x;
2662
2663 for (x=0; x<width; ++x)
2664 {
2665 png_byte bval = ppb[x];
2666 png_byte aval = ppa[x];
2667
2668 if (bval > bmax)
2669 bmax = bval;
2670
2671 if (bval != aval)
2672 match = 0;
2673
2674 in_use[aval] = 1;
2675 if (aval > amax)
2676 amax = aval;
2677 }
2678 }
2679
2680 /* If the buffers match then the colormaps must too. */
2681 if (match)
2682 {
2683 /* Do the color-maps match, entry by entry? Only check the 'in_use'
2684 * entries. An error here should be logged as a color-map error.
2685 */
2686 png_const_bytep a_cmap = (png_const_bytep)a->colormap;
2687 png_const_bytep b_cmap = (png_const_bytep)b->colormap;
2688 int result = 1; /* match by default */
2689
2690 /* This is used in logpixel to get the error message correct. */
2691 tr.is_palette = 1;
2692
2693 for (y=0; y<256; ++y, a_cmap += a_sample, b_cmap += b_sample)
2694 if (in_use[y])
2695 {
2696 /* The colormap entries should be valid, but because libpng doesn't
2697 * do any checking at present the original image may contain invalid
2698 * pixel values. These cause an error here (at present) unless
2699 * accumulating errors in which case the program just ignores them.
2700 */
2701 if (y >= a->image.colormap_entries)
2702 {
2703 if ((a->opts & ACCUMULATE) == 0)
2704 {
2705 char pindex[16];
2706 sprintf(pindex, "%lu[%lu]", (unsigned long)y,
2707 (unsigned long)a->image.colormap_entries);
2708 logerror(a, a->file_name, ": bad pixel index: ", pindex);
2709 }
2710 result = 0;
2711 }
2712
2713 else if (y >= b->image.colormap_entries)
2714 {
2715 if ((b->opts & ACCUMULATE) == 0)
2716 {
2717 char pindex[16];
2718 sprintf(pindex, "%lu[%lu]", (unsigned long)y,
2719 (unsigned long)b->image.colormap_entries);
2720 logerror(b, b->file_name, ": bad pixel index: ", pindex);
2721 }
2722 result = 0;
2723 }
2724
2725 /* All the mismatches are logged here; there can only be 256! */
2726 else if (!cmppixel(&tr, a_cmap, b_cmap, 0, y))
2727 result = 0;
2728 }
2729
2730 /* If requested, copy the error values back from the Transform. */
2731 if (a->opts & ACCUMULATE)
2732 {
2733 tr.error_ptr[0] = tr.error[0];
2734 tr.error_ptr[1] = tr.error[1];
2735 tr.error_ptr[2] = tr.error[2];
2736 tr.error_ptr[3] = tr.error[3];
2737 result = 1; /* force a continue */
2738 }
2739
2740 return result;
2741 }
2742
2743 /* else the image buffers don't match pixel-wise so compare sample values
2744 * instead, but first validate that the pixel indexes are in range (but
2745 * only if not accumulating, when the error is ignored.)
2746 */
2747 else if ((a->opts & ACCUMULATE) == 0)
2748 {
2749 # ifdef __GNUC__
2750 # define BYTE_CHARS 20 /* 2^32: GCC sprintf warning */
2751 # else
2752 # define BYTE_CHARS 3 /* 2^8: real maximum value */
2753 # endif
2754 /* Check the original image first,
2755 * TODO: deal with input images with bad pixel values?
2756 */
2757 if (amax >= a->image.colormap_entries)
2758 {
2759 char pindex[3+2*BYTE_CHARS];
2760 sprintf(pindex, "%d[%u]", amax,
2761 (png_byte)/*SAFE*/a->image.colormap_entries);
2762 return logerror(a, a->file_name, ": bad pixel index: ", pindex);
2763 }
2764
2765 else if (bmax >= b->image.colormap_entries)
2766 {
2767 char pindex[3+2*BYTE_CHARS];
2768 sprintf(pindex, "%d[%u]", bmax,
2769 (png_byte)/*SAFE*/b->image.colormap_entries);
2770 return logerror(b, b->file_name, ": bad pixel index: ", pindex);
2771 }
2772 }
2773 }
2774
2775 /* We can directly compare pixel values without the need to use the read
2776 * or transform support (i.e. a memory compare) if:
2777 *
2778 * 1) The bit depth has not changed.
2779 * 2) RGB to grayscale has not been done (the reverse is ok; we just compare
2780 * the three RGB values to the original grayscale.)
2781 * 3) An alpha channel has not been removed from an 8-bit format, or the
2782 * 8-bit alpha value of the pixel was 255 (opaque).
2783 *
2784 * If an alpha channel has been *added* then it must have the relevant opaque
2785 * value (255 or 65535).
2786 *
2787 * The fist two the tests (in the order given above) (using the boolean
2788 * equivalence !a && !b == !(a || b))
2789 */
2790 if (!(((formata ^ formatb) & PNG_FORMAT_FLAG_LINEAR) |
2791 (formata & (formatb ^ PNG_FORMAT_FLAG_COLOR) & PNG_FORMAT_FLAG_COLOR)))
2792 {
2793 /* Was an alpha channel changed? */
2794 png_uint_32 alpha_changed = (formata ^ formatb) & PNG_FORMAT_FLAG_ALPHA;
2795
2796 /* Was an alpha channel removed? (The third test.) If so the direct
2797 * comparison is only possible if the input alpha is opaque.
2798 */
2799 alpha_removed = (formata & alpha_changed) != 0;
2800
2801 /* Was an alpha channel added? */
2802 alpha_added = (formatb & alpha_changed) != 0;
2803
2804 /* The channels may have been moved between input and output, this finds
2805 * out how, recording the result in the btoa array, which says where in
2806 * 'a' to find each channel of 'b'. If alpha was added then btoa[alpha]
2807 * ends up as 4 (and is not used.)
2808 */
2809 {
2810 int i;
2811 png_byte aloc[4];
2812 png_byte bloc[4];
2813
2814 /* The following are used only if the formats match, except that
2815 * 'bchannels' is a flag for matching formats. btoa[x] says, for each
2816 * channel in b, where to find the corresponding value in a, for the
2817 * bchannels. achannels may be different for a gray to rgb transform
2818 * (a will be 1 or 2, b will be 3 or 4 channels.)
2819 */
2820 (void)component_loc(aloc, formata);
2821 bchannels = component_loc(bloc, formatb);
2822
2823 /* Hence the btoa array. */
2824 for (i=0; i<4; ++i)
2825 {
2826 if (bloc[i] < 4)
2827 btoa[bloc[i]] = aloc[i]; /* may be '4' for alpha */
2828 }
2829
2830 if (alpha_added)
2831 alpha_added = bloc[0]; /* location of alpha channel in image b */
2832
2833 else
2834 alpha_added = 4; /* Won't match an image b channel */
2835
2836 if (alpha_removed)
2837 alpha_removed = aloc[0]; /* location of alpha channel in image a */
2838
2839 else
2840 alpha_removed = 4;
2841 }
2842 }
2843
2844 else
2845 {
2846 /* Direct compare is not possible, cancel out all the corresponding local
2847 * variables.
2848 */
2849 bchannels = 0;
2850 alpha_removed = alpha_added = 4;
2851 btoa[3] = btoa[2] = btoa[1] = btoa[0] = 4; /* 4 == not present */
2852 }
2853
2854 for (y=0; y<height; ++y, rowa += stridea, rowb += strideb)
2855 {
2856 png_const_bytep ppa, ppb;
2857 png_uint_32 x;
2858
2859 for (x=0, ppa=rowa, ppb=rowb; x<width; ++x)
2860 {
2861 png_const_bytep psa, psb;
2862
2863 if (formata & PNG_FORMAT_FLAG_COLORMAP)
2864 psa = (png_const_bytep)a->colormap + a_sample * *ppa++;
2865 else
2866 psa = ppa, ppa += a_sample;
2867
2868 if (formatb & PNG_FORMAT_FLAG_COLORMAP)
2869 psb = (png_const_bytep)b->colormap + b_sample * *ppb++;
2870 else
2871 psb = ppb, ppb += b_sample;
2872
2873 /* Do the fast test if possible. */
2874 if (bchannels)
2875 {
2876 /* Check each 'b' channel against either the corresponding 'a'
2877 * channel or the opaque alpha value, as appropriate. If
2878 * alpha_removed value is set (not 4) then also do this only if the
2879 * 'a' alpha channel (alpha_removed) is opaque; only relevant for
2880 * the 8-bit case.
2881 */
2882 if (formatb & PNG_FORMAT_FLAG_LINEAR) /* 16-bit checks */
2883 {
2884 png_const_uint_16p pua = aligncastconst(png_const_uint_16p, psa);
2885 png_const_uint_16p pub = aligncastconst(png_const_uint_16p, psb);
2886
2887 switch (bchannels)
2888 {
2889 case 4:
2890 if (pua[btoa[3]] != pub[3]) break;
2891 /* FALLTHROUGH */
2892 case 3:
2893 if (pua[btoa[2]] != pub[2]) break;
2894 /* FALLTHROUGH */
2895 case 2:
2896 if (pua[btoa[1]] != pub[1]) break;
2897 /* FALLTHROUGH */
2898 case 1:
2899 if (pua[btoa[0]] != pub[0]) break;
2900 if (alpha_added != 4 && pub[alpha_added] != 65535) break;
2901 continue; /* x loop */
2902 default:
2903 break; /* impossible */
2904 }
2905 }
2906
2907 else if (alpha_removed == 4 || psa[alpha_removed] == 255)
2908 {
2909 switch (bchannels)
2910 {
2911 case 4:
2912 if (psa[btoa[3]] != psb[3]) break;
2913 /* FALLTHROUGH */
2914 case 3:
2915 if (psa[btoa[2]] != psb[2]) break;
2916 /* FALLTHROUGH */
2917 case 2:
2918 if (psa[btoa[1]] != psb[1]) break;
2919 /* FALLTHROUGH */
2920 case 1:
2921 if (psa[btoa[0]] != psb[0]) break;
2922 if (alpha_added != 4 && psb[alpha_added] != 255) break;
2923 continue; /* x loop */
2924 default:
2925 break; /* impossible */
2926 }
2927 }
2928 }
2929
2930 /* If we get to here the fast match failed; do the slow match for this
2931 * pixel.
2932 */
2933 if (!cmppixel(&tr, psa, psb, x, y) && (a->opts & KEEP_GOING) == 0)
2934 return 0; /* error case */
2935 }
2936 }
2937
2938 /* If requested, copy the error values back from the Transform. */
2939 if (a->opts & ACCUMULATE)
2940 {
2941 tr.error_ptr[0] = tr.error[0];
2942 tr.error_ptr[1] = tr.error[1];
2943 tr.error_ptr[2] = tr.error[2];
2944 tr.error_ptr[3] = tr.error[3];
2945 }
2946
2947 return 1;
2948 }
2949
2950 /* Read the file; how the read gets done depends on which of input_file and
2951 * input_memory have been set.
2952 */
2953 static int
2954 read_file(Image *image, png_uint_32 format, png_const_colorp background)
2955 {
2956 memset(&image->image, 0, sizeof image->image);
2957 image->image.version = PNG_IMAGE_VERSION;
2958
2959 if (image->input_memory != NULL)
2960 {
2961 if (!png_image_begin_read_from_memory(&image->image, image->input_memory,
2962 image->input_memory_size))
2963 return logerror(image, "memory init: ", image->file_name, "");
2964 }
2965
2966 # ifdef PNG_STDIO_SUPPORTED
2967 else if (image->input_file != NULL)
2968 {
2969 if (!png_image_begin_read_from_stdio(&image->image, image->input_file))
2970 return logerror(image, "stdio init: ", image->file_name, "");
2971 }
2972
2973 else
2974 {
2975 if (!png_image_begin_read_from_file(&image->image, image->file_name))
2976 return logerror(image, "file init: ", image->file_name, "");
2977 }
2978 # else
2979 else
2980 {
2981 return logerror(image, "unsupported file/stdio init: ",
2982 image->file_name, "");
2983 }
2984 # endif
2985
2986 /* This must be set after the begin_read call: */
2987 if (image->opts & sRGB_16BIT)
2988 image->image.flags |= PNG_IMAGE_FLAG_16BIT_sRGB;
2989
2990 /* Have an initialized image with all the data we need plus, maybe, an
2991 * allocated file (myfile) or buffer (mybuffer) that need to be freed.
2992 */
2993 {
2994 int result;
2995 png_uint_32 image_format;
2996
2997 /* Print both original and output formats. */
2998 image_format = image->image.format;
2999
3000 if (image->opts & VERBOSE)
3001 {
3002 printf("%s %lu x %lu %s -> %s", image->file_name,
3003 (unsigned long)image->image.width,
3004 (unsigned long)image->image.height,
3005 format_names[image_format & FORMAT_MASK],
3006 (format & FORMAT_NO_CHANGE) != 0 || image->image.format == format
3007 ? "no change" : format_names[format & FORMAT_MASK]);
3008
3009 if (background != NULL)
3010 printf(" background(%d,%d,%d)\n", background->red,
3011 background->green, background->blue);
3012 else
3013 printf("\n");
3014
3015 fflush(stdout);
3016 }
3017
3018 /* 'NO_CHANGE' combined with the color-map flag forces the base format
3019 * flags to be set on read to ensure that the original representation is
3020 * not lost in the pass through a colormap format.
3021 */
3022 if ((format & FORMAT_NO_CHANGE) != 0)
3023 {
3024 if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0 &&
3025 (image_format & PNG_FORMAT_FLAG_COLORMAP) != 0)
3026 format = (image_format & ~BASE_FORMATS) | (format & BASE_FORMATS);
3027
3028 else
3029 format = image_format;
3030 }
3031
3032 image->image.format = format;
3033
3034 image->stride = PNG_IMAGE_ROW_STRIDE(image->image) + image->stride_extra;
3035 allocbuffer(image);
3036
3037 result = png_image_finish_read(&image->image, background,
3038 image->buffer+16, (png_int_32)image->stride, image->colormap);
3039
3040 checkbuffer(image, image->file_name);
3041
3042 if (result)
3043 return checkopaque(image);
3044
3045 else
3046 return logerror(image, image->file_name, ": image read failed", "");
3047 }
3048 }
3049
3050 /* Reads from a filename, which must be in image->file_name, but uses
3051 * image->opts to choose the method. The file is always read in its native
3052 * format (the one the simplified API suggests).
3053 */
3054 static int
3055 read_one_file(Image *image)
3056 {
3057 if (!(image->opts & USE_FILE) || (image->opts & USE_STDIO))
3058 {
3059 /* memory or stdio. */
3060 FILE *f = fopen(image->file_name, "rb");
3061
3062 if (f != NULL)
3063 {
3064 if (image->opts & USE_FILE)
3065 image->input_file = f;
3066
3067 else /* memory */
3068 {
3069 if (fseek(f, 0, SEEK_END) == 0)
3070 {
3071 long int cb = ftell(f);
3072
3073 if (cb > 0)
3074 {
3075 #ifndef __COVERITY__
3076 if ((unsigned long int)cb <= (size_t)~(size_t)0)
3077 #endif
3078 {
3079 png_bytep b = voidcast(png_bytep, malloc((size_t)cb));
3080
3081 if (b != NULL)
3082 {
3083 rewind(f);
3084
3085 if (fread(b, (size_t)cb, 1, f) == 1)
3086 {
3087 fclose(f);
3088 image->input_memory_size = cb;
3089 image->input_memory = b;
3090 }
3091
3092 else
3093 {
3094 free(b);
3095 return logclose(image, f, image->file_name,
3096 ": read failed: ");
3097 }
3098 }
3099
3100 else
3101 return logclose(image, f, image->file_name,
3102 ": out of memory: ");
3103 }
3104
3105 else
3106 return logclose(image, f, image->file_name,
3107 ": file too big for this architecture: ");
3108 /* cb is the length of the file as a (long) and
3109 * this is greater than the maximum amount of
3110 * memory that can be requested from malloc.
3111 */
3112 }
3113
3114 else if (cb == 0)
3115 return logclose(image, f, image->file_name,
3116 ": zero length: ");
3117
3118 else
3119 return logclose(image, f, image->file_name,
3120 ": tell failed: ");
3121 }
3122
3123 else
3124 return logclose(image, f, image->file_name, ": seek failed: ");
3125 }
3126 }
3127
3128 else
3129 return logerror(image, image->file_name, ": open failed: ",
3130 strerror(errno));
3131 }
3132
3133 return read_file(image, FORMAT_NO_CHANGE, NULL);
3134 }
3135
3136 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
3137 static int
3138 write_one_file(Image *output, Image *image, int convert_to_8bit)
3139 {
3140 if (image->opts & FAST_WRITE)
3141 image->image.flags |= PNG_IMAGE_FLAG_FAST;
3142
3143 if (image->opts & USE_STDIO)
3144 {
3145 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
3146 #ifndef __COVERITY__
3147 FILE *f = tmpfile();
3148 #else
3149 /* Experimental. Coverity says tmpfile() is insecure because it
3150 * generates predictable names.
3151 *
3152 * It is possible to satisfy Coverity by using mkstemp(); however,
3153 * any platform supporting mkstemp() undoubtedly has a secure tmpfile()
3154 * implementation as well, and doesn't need the fix. Note that
3155 * the fix won't work on platforms that don't support mkstemp().
3156 *
3157 * https://www.securecoding.cert.org/confluence/display/c/
3158 * FIO21-C.+Do+not+create+temporary+files+in+shared+directories
3159 * says that most historic implementations of tmpfile() provide
3160 * only a limited number of possible temporary file names
3161 * (usually 26) before file names are recycled. That article also
3162 * provides a secure solution that unfortunately depends upon mkstemp().
3163 */
3164 char tmpfile[] = "pngstest-XXXXXX";
3165 int filedes;
3166 FILE *f;
3167 umask(0177);
3168 filedes = mkstemp(tmpfile);
3169 if (filedes < 0)
3170 f = NULL;
3171 else
3172 {
3173 f = fdopen(filedes,"w+");
3174 /* Hide the filename immediately and ensure that the file does
3175 * not exist after the program ends
3176 */
3177 (void) unlink(tmpfile);
3178 }
3179 #endif
3180
3181 if (f != NULL)
3182 {
3183 if (png_image_write_to_stdio(&image->image, f, convert_to_8bit,
3184 image->buffer+16, (png_int_32)image->stride, image->colormap))
3185 {
3186 if (fflush(f) == 0)
3187 {
3188 rewind(f);
3189 initimage(output, image->opts, "tmpfile", image->stride_extra);
3190 output->input_file = f;
3191 if (!checkopaque(image))
3192 return 0;
3193 }
3194
3195 else
3196 return logclose(image, f, "tmpfile", ": flush: ");
3197 }
3198
3199 else
3200 {
3201 fclose(f);
3202 return logerror(image, "tmpfile", ": write failed", "");
3203 }
3204 }
3205
3206 else
3207 return logerror(image, "tmpfile", ": open: ", strerror(errno));
3208 #else /* SIMPLIFIED_WRITE_STDIO */
3209 return logerror(image, "tmpfile", ": open: unsupported", "");
3210 #endif /* SIMPLIFIED_WRITE_STDIO */
3211 }
3212
3213 else if (image->opts & USE_FILE)
3214 {
3215 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
3216 static unsigned int counter = 0;
3217 char name[32];
3218
3219 sprintf(name, "%s%u.png", tmpf, ++counter);
3220
3221 if (png_image_write_to_file(&image->image, name, convert_to_8bit,
3222 image->buffer+16, (png_int_32)image->stride, image->colormap))
3223 {
3224 initimage(output, image->opts, output->tmpfile_name,
3225 image->stride_extra);
3226 /* Afterwards, or freeimage will delete it! */
3227 strcpy(output->tmpfile_name, name);
3228
3229 if (!checkopaque(image))
3230 return 0;
3231 }
3232
3233 else
3234 return logerror(image, name, ": write failed", "");
3235 #else /* SIMPLIFIED_WRITE_STDIO */
3236 return logerror(image, "stdio", ": open: unsupported", "");
3237 #endif /* SIMPLIFIED_WRITE_STDIO */
3238 }
3239
3240 else /* use memory */
3241 {
3242 png_alloc_size_t size;
3243
3244 if (png_image_write_get_memory_size(image->image, size, convert_to_8bit,
3245 image->buffer+16, (png_int_32)image->stride, image->colormap))
3246 {
3247 /* This is non-fatal but ignoring it was causing serious problems in
3248 * the macro to be ignored:
3249 */
3250 if (size > PNG_IMAGE_PNG_SIZE_MAX(image->image))
3251 return logerror(image, "memory", ": PNG_IMAGE_SIZE_MAX wrong", "");
3252
3253 initimage(output, image->opts, "memory", image->stride_extra);
3254 output->input_memory = malloc(size);
3255
3256 if (output->input_memory != NULL)
3257 {
3258 output->input_memory_size = size;
3259
3260 if (png_image_write_to_memory(&image->image, output->input_memory,
3261 &output->input_memory_size, convert_to_8bit, image->buffer+16,
3262 (png_int_32)image->stride, image->colormap))
3263 {
3264 /* This is also non-fatal but it safes safer to error out anyway:
3265 */
3266 if (size != output->input_memory_size)
3267 return logerror(image, "memory", ": memory size wrong", "");
3268 }
3269
3270 else
3271 return logerror(image, "memory", ": write failed", "");
3272 }
3273
3274 else
3275 return logerror(image, "memory", ": out of memory", "");
3276 }
3277
3278 else
3279 return logerror(image, "memory", ": get size:", "");
3280 }
3281
3282 /* 'output' has an initialized temporary image, read this back in and compare
3283 * this against the original: there should be no change since the original
3284 * format was written unmodified unless 'convert_to_8bit' was specified.
3285 * However, if the original image was color-mapped, a simple read will zap
3286 * the linear, color and maybe alpha flags, this will cause spurious failures
3287 * under some circumstances.
3288 */
3289 if (read_file(output, image->image.format | FORMAT_NO_CHANGE, NULL))
3290 {
3291 png_uint_32 original_format = image->image.format;
3292
3293 if (convert_to_8bit)
3294 original_format &= ~PNG_FORMAT_FLAG_LINEAR;
3295
3296 if ((output->image.format & BASE_FORMATS) !=
3297 (original_format & BASE_FORMATS))
3298 return logerror(image, image->file_name, ": format changed on read: ",
3299 output->file_name);
3300
3301 return compare_two_images(image, output, 0/*via linear*/, NULL);
3302 }
3303
3304 else
3305 return logerror(output, output->tmpfile_name,
3306 ": read of new file failed", "");
3307 }
3308 #endif
3309
3310 static int
3311 testimage(Image *image, png_uint_32 opts, format_list *pf)
3312 {
3313 int result;
3314 Image copy;
3315
3316 /* Copy the original data, stealing it from 'image' */
3317 checkopaque(image);
3318 copy = *image;
3319
3320 copy.opts = opts;
3321 copy.buffer = NULL;
3322 copy.bufsize = 0;
3323 copy.allocsize = 0;
3324
3325 image->input_file = NULL;
3326 image->input_memory = NULL;
3327 image->input_memory_size = 0;
3328 image->tmpfile_name[0] = 0;
3329
3330 {
3331 png_uint_32 counter;
3332 Image output;
3333
3334 newimage(&output);
3335
3336 result = 1;
3337
3338 /* Use the low bit of 'counter' to indicate whether or not to do alpha
3339 * removal with a background color or by composting onto the image; this
3340 * step gets skipped if it isn't relevant
3341 */
3342 for (counter=0; counter<2*FORMAT_COUNT; ++counter)
3343 if (format_isset(pf, counter >> 1))
3344 {
3345 png_uint_32 format = counter >> 1;
3346
3347 png_color background_color;
3348 png_colorp background = NULL;
3349
3350 /* If there is a format change that removes the alpha channel then
3351 * the background is relevant. If the output is 8-bit color-mapped
3352 * then a background color *must* be provided, otherwise there are
3353 * two tests to do - one with a color, the other with NULL. The
3354 * NULL test happens second.
3355 */
3356 if ((counter & 1) == 0)
3357 {
3358 if ((format & PNG_FORMAT_FLAG_ALPHA) == 0 &&
3359 (image->image.format & PNG_FORMAT_FLAG_ALPHA) != 0)
3360 {
3361 /* Alpha/transparency will be removed, the background is
3362 * relevant: make it a color the first time
3363 */
3364 random_color(&background_color);
3365 background = &background_color;
3366
3367 /* BUT if the output is to a color-mapped 8-bit format then
3368 * the background must always be a color, so increment 'counter'
3369 * to skip the NULL test.
3370 */
3371 if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0 &&
3372 (format & PNG_FORMAT_FLAG_LINEAR) == 0)
3373 ++counter;
3374 }
3375
3376 /* Otherwise an alpha channel is not being eliminated, just leave
3377 * background NULL and skip the (counter & 1) NULL test.
3378 */
3379 else
3380 ++counter;
3381 }
3382 /* else just use NULL for background */
3383
3384 resetimage(©);
3385 copy.opts = opts; /* in case read_file needs to change it */
3386
3387 result = read_file(©, format, background);
3388 if (!result)
3389 break;
3390
3391 /* Make sure the file just read matches the original file. */
3392 result = compare_two_images(image, ©, 0/*via linear*/, background);
3393 if (!result)
3394 break;
3395
3396 # ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
3397 /* Write the *copy* just made to a new file to make sure the write
3398 * side works ok. Check the conversion to sRGB if the copy is
3399 * linear.
3400 */
3401 output.opts = opts;
3402 result = write_one_file(&output, ©, 0/*convert to 8bit*/);
3403 if (!result)
3404 break;
3405
3406 /* Validate against the original too; the background is needed here
3407 * as well so that compare_two_images knows what color was used.
3408 */
3409 result = compare_two_images(image, &output, 0, background);
3410 if (!result)
3411 break;
3412
3413 if ((format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
3414 (format & PNG_FORMAT_FLAG_COLORMAP) == 0)
3415 {
3416 /* 'output' is linear, convert to the corresponding sRGB format.
3417 */
3418 output.opts = opts;
3419 result = write_one_file(&output, ©, 1/*convert to 8bit*/);
3420 if (!result)
3421 break;
3422
3423 /* This may involve a conversion via linear; in the ideal world
3424 * this would round-trip correctly, but libpng 1.5.7 is not the
3425 * ideal world so allow a drift (error_via_linear).
3426 *
3427 * 'image' has an alpha channel but 'output' does not then there
3428 * will a strip-alpha-channel operation (because 'output' is
3429 * linear), handle this by composing on black when doing the
3430 * comparison.
3431 */
3432 result = compare_two_images(image, &output, 1/*via_linear*/,
3433 background);
3434 if (!result)
3435 break;
3436 }
3437 # endif /* PNG_SIMPLIFIED_WRITE_SUPPORTED */
3438 }
3439
3440 freeimage(&output);
3441 }
3442
3443 freeimage(©);
3444
3445 return result;
3446 }
3447
3448 static int
3449 test_one_file(const char *file_name, format_list *formats, png_uint_32 opts,
3450 int stride_extra, int log_pass)
3451 {
3452 int result;
3453 Image image;
3454
3455 if (!(opts & NO_RESEED))
3456 reseed(); /* ensure that the random numbers don't depend on file order */
3457 newimage(&image);
3458 initimage(&image, opts, file_name, stride_extra);
3459 result = read_one_file(&image);
3460 if (result)
3461 result = testimage(&image, opts, formats);
3462 freeimage(&image);
3463
3464 /* Ensure that stderr is flushed into any log file */
3465 fflush(stderr);
3466
3467 if (log_pass)
3468 {
3469 if (result)
3470 printf("PASS:");
3471
3472 else
3473 printf("FAIL:");
3474
3475 # ifndef PNG_SIMPLIFIED_WRITE_SUPPORTED
3476 printf(" (no write)");
3477 # endif
3478
3479 print_opts(opts);
3480 printf(" %s\n", file_name);
3481 /* stdout may not be line-buffered if it is piped to a file, so: */
3482 fflush(stdout);
3483 }
3484
3485 else if (!result)
3486 exit(1);
3487
3488 return result;
3489 }
3490
3491 int
3492 main(int argc, char **argv)
3493 {
3494 png_uint_32 opts = FAST_WRITE | STRICT;
3495 format_list formats;
3496 const char *touch = NULL;
3497 int log_pass = 0;
3498 int redundant = 0;
3499 int stride_extra = 0;
3500 int retval = 0;
3501 int c;
3502
3503 #if PNG_LIBPNG_VER >= 10700
3504 /* This error should not exist in 1.7 or later: */
3505 opts |= GBG_ERROR;
3506 #endif
3507
3508 init_sRGB_to_d();
3509 #if 0
3510 init_error_via_linear();
3511 #endif
3512 format_init(&formats);
3513 reseed(); /* initialize random number seeds */
3514
3515 for (c=1; c<argc; ++c)
3516 {
3517 const char *arg = argv[c];
3518
3519 if (strcmp(arg, "--log") == 0)
3520 log_pass = 1;
3521 else if (strcmp(arg, "--fresh") == 0)
3522 {
3523 memset(gpc_error, 0, sizeof gpc_error);
3524 memset(gpc_error_via_linear, 0, sizeof gpc_error_via_linear);
3525 }
3526 else if (strcmp(arg, "--file") == 0)
3527 # ifdef PNG_STDIO_SUPPORTED
3528 opts |= USE_FILE;
3529 # else
3530 return SKIP; /* skipped: no support */
3531 # endif
3532 else if (strcmp(arg, "--memory") == 0)
3533 opts &= ~USE_FILE;
3534 else if (strcmp(arg, "--stdio") == 0)
3535 # ifdef PNG_STDIO_SUPPORTED
3536 opts |= USE_STDIO;
3537 # else
3538 return SKIP; /* skipped: no support */
3539 # endif
3540 else if (strcmp(arg, "--name") == 0)
3541 opts &= ~USE_STDIO;
3542 else if (strcmp(arg, "--verbose") == 0)
3543 opts |= VERBOSE;
3544 else if (strcmp(arg, "--quiet") == 0)
3545 opts &= ~VERBOSE;
3546 else if (strcmp(arg, "--preserve") == 0)
3547 opts |= KEEP_TMPFILES;
3548 else if (strcmp(arg, "--nopreserve") == 0)
3549 opts &= ~KEEP_TMPFILES;
3550 else if (strcmp(arg, "--keep-going") == 0)
3551 opts |= KEEP_GOING;
3552 else if (strcmp(arg, "--fast") == 0)
3553 opts |= FAST_WRITE;
3554 else if (strcmp(arg, "--slow") == 0)
3555 opts &= ~FAST_WRITE;
3556 else if (strcmp(arg, "--accumulate") == 0)
3557 opts |= ACCUMULATE;
3558 else if (strcmp(arg, "--redundant") == 0)
3559 redundant = 1;
3560 else if (strcmp(arg, "--stop") == 0)
3561 opts &= ~KEEP_GOING;
3562 else if (strcmp(arg, "--strict") == 0)
3563 opts |= STRICT;
3564 else if (strcmp(arg, "--nostrict") == 0)
3565 opts &= ~STRICT;
3566 else if (strcmp(arg, "--sRGB-16bit") == 0)
3567 opts |= sRGB_16BIT;
3568 else if (strcmp(arg, "--linear-16bit") == 0)
3569 opts &= ~sRGB_16BIT;
3570 else if (strcmp(arg, "--noreseed") == 0)
3571 opts |= NO_RESEED;
3572 else if (strcmp(arg, "--fault-gbg-warning") == 0)
3573 opts |= GBG_ERROR;
3574 else if (strcmp(arg, "--tmpfile") == 0)
3575 {
3576 if (c+1 < argc)
3577 {
3578 if (strlen(argv[++c]) >= sizeof tmpf)
3579 {
3580 fflush(stdout);
3581 fprintf(stderr, "%s: %s is too long for a temp file prefix\n",
3582 argv[0], argv[c]);
3583 exit(99);
3584 }
3585
3586 /* Safe: checked above */
3587 strncpy(tmpf, argv[c], sizeof (tmpf)-1);
3588 }
3589
3590 else
3591 {
3592 fflush(stdout);
3593 fprintf(stderr, "%s: %s requires a temporary file prefix\n",
3594 argv[0], arg);
3595 exit(99);
3596 }
3597 }
3598 else if (strcmp(arg, "--touch") == 0)
3599 {
3600 if (c+1 < argc)
3601 touch = argv[++c];
3602
3603 else
3604 {
3605 fflush(stdout);
3606 fprintf(stderr, "%s: %s requires a file name argument\n",
3607 argv[0], arg);
3608 exit(99);
3609 }
3610 }
3611 else if (arg[0] == '+')
3612 {
3613 png_uint_32 format = formatof(arg+1);
3614
3615 if (format > FORMAT_COUNT)
3616 exit(99);
3617
3618 format_set(&formats, format);
3619 }
3620 else if (arg[0] == '-' && arg[1] != 0 && (arg[1] != '0' || arg[2] != 0))
3621 {
3622 fflush(stdout);
3623 fprintf(stderr, "%s: unknown option: %s\n", argv[0], arg);
3624 exit(99);
3625 }
3626 else
3627 {
3628 if (format_is_initial(&formats))
3629 format_default(&formats, redundant);
3630
3631 if (arg[0] == '-')
3632 {
3633 int term = (arg[1] == '0' ? 0 : '\n');
3634 unsigned int ich = 0;
3635
3636 /* Loop reading files, use a static buffer to simplify this and just
3637 * stop if the name gets to long.
3638 */
3639 static char buffer[4096];
3640
3641 do
3642 {
3643 int ch = getchar();
3644
3645 /* Don't allow '\0' in file names, and terminate with '\n' or,
3646 * for -0, just '\0' (use -print0 to find to make this work!)
3647 */
3648 if (ch == EOF || ch == term || ch == 0)
3649 {
3650 buffer[ich] = 0;
3651
3652 if (ich > 0 && !test_one_file(buffer, &formats, opts,
3653 stride_extra, log_pass))
3654 retval = 1;
3655
3656 if (ch == EOF)
3657 break;
3658
3659 ich = 0;
3660 --ich; /* so that the increment below sets it to 0 again */
3661 }
3662
3663 else
3664 buffer[ich] = (char)ch;
3665 } while (++ich < sizeof buffer);
3666
3667 if (ich)
3668 {
3669 buffer[32] = 0;
3670 buffer[4095] = 0;
3671 fprintf(stderr, "%s...%s: file name too long\n", buffer,
3672 buffer+(4096-32));
3673 exit(99);
3674 }
3675 }
3676
3677 else if (!test_one_file(arg, &formats, opts, stride_extra, log_pass))
3678 retval = 1;
3679 }
3680 }
3681
3682 if (opts & ACCUMULATE)
3683 {
3684 unsigned int in;
3685
3686 printf("/* contrib/libtests/pngstest-errors.h\n");
3687 printf(" *\n");
3688 printf(" * BUILT USING:" PNG_HEADER_VERSION_STRING);
3689 printf(" *\n");
3690 printf(" * This code is released under the libpng license.\n");
3691 printf(" * For conditions of distribution and use, see the disclaimer\n");
3692 printf(" * and license in png.h\n");
3693 printf(" *\n");
3694 printf(" * THIS IS A MACHINE GENERATED FILE: do not edit it directly!\n");
3695 printf(" * Instead run:\n");
3696 printf(" *\n");
3697 printf(" * pngstest --accumulate\n");
3698 printf(" *\n");
3699 printf(" * on as many PNG files as possible; at least PNGSuite and\n");
3700 printf(" * contrib/libtests/testpngs.\n");
3701 printf(" */\n");
3702
3703 printf("static png_uint_16 gpc_error[16/*in*/][16/*out*/][4/*a*/] =\n");
3704 printf("{\n");
3705 for (in=0; in<16; ++in)
3706 {
3707 unsigned int out;
3708 printf(" { /* input: %s */\n ", format_names[in]);
3709 for (out=0; out<16; ++out)
3710 {
3711 unsigned int alpha;
3712 printf(" {");
3713 for (alpha=0; alpha<4; ++alpha)
3714 {
3715 printf(" %d", gpc_error[in][out][alpha]);
3716 if (alpha < 3) putchar(',');
3717 }
3718 printf(" }");
3719 if (out < 15)
3720 {
3721 putchar(',');
3722 if (out % 4 == 3) printf("\n ");
3723 }
3724 }
3725 printf("\n }");
3726
3727 if (in < 15)
3728 putchar(',');
3729 else
3730 putchar('\n');
3731 }
3732 printf("};\n");
3733
3734 printf("static png_uint_16 gpc_error_via_linear[16][4/*out*/][4] =\n");
3735 printf("{\n");
3736 for (in=0; in<16; ++in)
3737 {
3738 unsigned int out;
3739 printf(" { /* input: %s */\n ", format_names[in]);
3740 for (out=0; out<4; ++out)
3741 {
3742 unsigned int alpha;
3743 printf(" {");
3744 for (alpha=0; alpha<4; ++alpha)
3745 {
3746 printf(" %d", gpc_error_via_linear[in][out][alpha]);
3747 if (alpha < 3) putchar(',');
3748 }
3749 printf(" }");
3750 if (out < 3)
3751 putchar(',');
3752 }
3753 printf("\n }");
3754
3755 if (in < 15)
3756 putchar(',');
3757 else
3758 putchar('\n');
3759 }
3760 printf("};\n");
3761
3762 printf("static png_uint_16 gpc_error_to_colormap[8/*i*/][8/*o*/][4] =\n");
3763 printf("{\n");
3764 for (in=0; in<8; ++in)
3765 {
3766 unsigned int out;
3767 printf(" { /* input: %s */\n ", format_names[in]);
3768 for (out=0; out<8; ++out)
3769 {
3770 unsigned int alpha;
3771 printf(" {");
3772 for (alpha=0; alpha<4; ++alpha)
3773 {
3774 printf(" %d", gpc_error_to_colormap[in][out][alpha]);
3775 if (alpha < 3) putchar(',');
3776 }
3777 printf(" }");
3778 if (out < 7)
3779 {
3780 putchar(',');
3781 if (out % 4 == 3) printf("\n ");
3782 }
3783 }
3784 printf("\n }");
3785
3786 if (in < 7)
3787 putchar(',');
3788 else
3789 putchar('\n');
3790 }
3791 printf("};\n");
3792 printf("/* END MACHINE GENERATED */\n");
3793 }
3794
3795 if (retval == 0 && touch != NULL)
3796 {
3797 FILE *fsuccess = fopen(touch, "wt");
3798
3799 if (fsuccess != NULL)
3800 {
3801 int error = 0;
3802 fprintf(fsuccess, "PNG simple API tests succeeded\n");
3803 fflush(fsuccess);
3804 error = ferror(fsuccess);
3805
3806 if (fclose(fsuccess) || error)
3807 {
3808 fflush(stdout);
3809 fprintf(stderr, "%s: write failed\n", touch);
3810 exit(99);
3811 }
3812 }
3813
3814 else
3815 {
3816 fflush(stdout);
3817 fprintf(stderr, "%s: open failed\n", touch);
3818 exit(99);
3819 }
3820 }
3821
3822 return retval;
3823 }
3824
3825 #else /* !PNG_SIMPLIFIED_READ_SUPPORTED */
3826 int main(void)
3827 {
3828 fprintf(stderr, "pngstest: no read support in libpng, test skipped\n");
3829 /* So the test is skipped: */
3830 return SKIP;
3831 }
3832 #endif /* PNG_SIMPLIFIED_READ_SUPPORTED */