2 /* pngvalid.c - validate libpng by constructing then reading png files.
4 * Copyright (c) 2021 Cosmin Truta
5 * Copyright (c) 2014-2017 John Cunningham Bowler
7 * This code is released under the libpng license.
8 * For conditions of distribution and use, see the disclaimer
12 * This is a C program that is intended to be linked against libpng. It
13 * generates bitmaps internally, stores them as PNG files (using the
14 * sequential write code) then reads them back (using the sequential
15 * read code) and validates that the result has the correct data.
17 * The program can be modified and extended to test the correctness of
18 * transformations performed by libpng.
21 #define _POSIX_SOURCE 1
22 #define _ISOC99_SOURCE 1 /* For floating point */
23 #define _GNU_SOURCE 1 /* For the floating point exception extension */
24 #define _BSD_SOURCE 1 /* For the floating point exception extension */
25 #define _DEFAULT_SOURCE 1 /* For the floating point exception extension */
30 #if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
34 #ifdef HAVE_FEENABLEEXCEPT /* from config.h, if included */
39 # define FE_DIVBYZERO 0
45 # define FE_OVERFLOW 0
48 /* Define the following to use this test against your installed libpng, rather
49 * than the one being built here:
51 #ifdef PNG_FREESTANDING_TESTS
54 # include "../../png.h"
57 #ifdef PNG_ZLIB_HEADER
58 # include PNG_ZLIB_HEADER
60 # include <zlib.h> /* For crc32 */
63 /* 1.6.1 added support for the configure test harness, which uses 77 to indicate
64 * a skipped test, in earlier versions we need to succeed on a skipped test, so:
66 #if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
72 /* pngvalid requires write support and one of the fixed or floating point APIs.
74 #if defined(PNG_WRITE_SUPPORTED) &&\
75 (defined(PNG_FIXED_POINT_SUPPORTED) || defined(PNG_FLOATING_POINT_SUPPORTED))
77 #if PNG_LIBPNG_VER < 10500
78 /* This deliberately lacks the const. */
79 typedef png_byte *png_const_bytep;
81 /* This is copied from 1.5.1 png.h: */
82 #define PNG_INTERLACE_ADAM7_PASSES 7
83 #define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
84 #define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
85 #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
86 #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
87 #define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
88 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
89 #define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
90 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
91 #define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
92 (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
93 #define PNG_COL_FROM_PASS_COL(xIn, pass) \
94 (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
95 #define PNG_PASS_MASK(pass,off) ( \
96 ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
97 ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
98 #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
99 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
100 #define PNG_COL_IN_INTERLACE_PASS(x, pass) \
101 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
103 /* These are needed too for the default build: */
104 #define PNG_WRITE_16BIT_SUPPORTED
105 #define PNG_READ_16BIT_SUPPORTED
107 /* This comes from pnglibconf.h after 1.5: */
108 #define PNG_FP_1 100000
109 #define PNG_GAMMA_THRESHOLD_FIXED\
110 ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
113 #if PNG_LIBPNG_VER < 10600
114 /* 1.6.0 constifies many APIs, the following exists to allow pngvalid to be
115 * compiled against earlier versions.
117 # define png_const_structp png_structp
120 #ifndef RELEASE_BUILD
121 /* RELEASE_BUILD is true for releases and release candidates: */
122 # define RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
125 # define debugonly(something)
126 #else /* !RELEASE_BUILD */
127 # define debugonly(something) something
128 #endif /* !RELEASE_BUILD */
130 #include <float.h> /* For floating point constants */
131 #include <stdlib.h> /* For malloc */
132 #include <string.h> /* For memcpy, memset */
133 #include <math.h> /* For floor */
135 /* Convenience macros. */
136 #define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
137 #define CHUNK_IHDR CHUNK(73,72,68,82)
138 #define CHUNK_PLTE CHUNK(80,76,84,69)
139 #define CHUNK_IDAT CHUNK(73,68,65,84)
140 #define CHUNK_IEND CHUNK(73,69,78,68)
141 #define CHUNK_cHRM CHUNK(99,72,82,77)
142 #define CHUNK_gAMA CHUNK(103,65,77,65)
143 #define CHUNK_sBIT CHUNK(115,66,73,84)
144 #define CHUNK_sRGB CHUNK(115,82,71,66)
146 /* Unused formal parameter errors are removed using the following macro which is
147 * expected to have no bad effects on performance.
150 # if defined(__GNUC__) || defined(_MSC_VER)
151 # define UNUSED(param) (void)param;
153 # define UNUSED(param)
157 /***************************** EXCEPTION HANDLING *****************************/
158 #ifdef PNG_FREESTANDING_TESTS
159 # include <cexcept.h>
161 # include "../visupng/cexcept.h"
165 # define this not_the_cpp_this
166 # define new not_the_cpp_new
167 # define voidcast(type, value) static_cast<type>(value)
169 # define voidcast(type, value) (value)
170 #endif /* __cplusplus */
173 define_exception_type(struct png_store*);
175 /* The following are macros to reduce typing everywhere where the well known
176 * name 'the_exception_context' must be defined.
178 #define anon_context(ps) struct exception_context *the_exception_context = \
179 &(ps)->exception_context
180 #define context(ps,fault) anon_context(ps); png_store *fault
182 /* This macro returns the number of elements in an array as an (unsigned int),
183 * it is necessary to avoid the inability of certain versions of GCC to use
184 * the value of a compile-time constant when performing range checks. It must
185 * be passed an array name.
187 #define ARRAY_SIZE(a) ((unsigned int)((sizeof (a))/(sizeof (a)[0])))
189 /* GCC BUG 66447 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66447) requires
190 * some broken GCC versions to be fixed up to avoid invalid whining about auto
191 * variables that are *not* changed within the scope of a setjmp being changed.
193 * Feel free to extend the list of broken versions.
195 #define is_gnu(major,minor)\
196 (defined __GNUC__) && __GNUC__ == (major) && __GNUC_MINOR__ == (minor)
197 #define is_gnu_patch(major,minor,patch)\
198 is_gnu(major,minor) && __GNUC_PATCHLEVEL__ == 0
199 /* For the moment just do it always; all versions of GCC seem to be broken: */
201 const void * volatile make_volatile_for_gnu;
202 # define gnu_volatile(x) make_volatile_for_gnu = &x;
203 #else /* !GNUC broken versions */
204 # define gnu_volatile(x)
205 #endif /* !GNUC broken versions */
207 /******************************* UTILITIES ************************************/
208 /* Error handling is particularly problematic in production code - error
209 * handlers often themselves have bugs which lead to programs that detect
210 * minor errors crashing. The following functions deal with one very
211 * common class of errors in error handlers - attempting to format error or
212 * warning messages into buffers that are too small.
214 static size_t safecat(char *buffer, size_t bufsize, size_t pos,
217 while (pos < bufsize && cat != NULL && *cat != 0)
218 buffer[pos++] = *cat++;
227 static size_t safecatn(char *buffer, size_t bufsize, size_t pos, int n)
230 sprintf(number, "%d", n);
231 return safecat(buffer, bufsize, pos, number);
234 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
235 static size_t safecatd(char *buffer, size_t bufsize, size_t pos, double d,
239 sprintf(number, "%.*f", precision, d);
240 return safecat(buffer, bufsize, pos, number);
244 static const char invalid[] = "invalid";
245 static const char sep[] = ": ";
247 static const char *colour_types[8] =
249 "grayscale", invalid, "truecolour", "indexed-colour",
250 "grayscale with alpha", invalid, "truecolour with alpha", invalid
253 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
254 /* Convert a double precision value to fixed point. */
255 static png_fixed_point
258 d = floor(d * PNG_FP_1 + .5);
259 return (png_fixed_point)d;
261 #endif /* PNG_READ_SUPPORTED */
263 /* Generate random bytes. This uses a boring repeatable algorithm and it
264 * is implemented here so that it gives the same set of numbers on every
265 * architecture. It's a linear congruential generator (Knuth or Sedgewick
266 * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
267 * Hill, "The Art of Electronics" (Pseudo-Random Bit Sequences and Noise
271 make_random_bytes(png_uint_32* seed, void* pv, size_t size)
273 png_uint_32 u0 = seed[0], u1 = seed[1];
274 png_bytep bytes = voidcast(png_bytep, pv);
276 /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
277 * bit-20. The top 1 bit is in u1, the bottom 32 are in u0.
280 for (i=0; i<size; ++i)
282 /* First generate 8 new bits then shift them in at the end. */
283 png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
288 *bytes++ = (png_byte)u;
296 make_four_random_bytes(png_uint_32* seed, png_bytep bytes)
298 make_random_bytes(seed, bytes, 4);
301 #if defined PNG_READ_SUPPORTED || defined PNG_WRITE_tRNS_SUPPORTED ||\
302 defined PNG_WRITE_FILTER_SUPPORTED
304 randomize(void *pv, size_t size)
306 static png_uint_32 random_seed[2] = {0x56789abc, 0xd};
307 make_random_bytes(random_seed, pv, size);
310 #define R8(this) randomize(&(this), sizeof (this))
312 #ifdef PNG_READ_SUPPORTED
317 randomize(b1, sizeof b1);
326 randomize(b2, sizeof b2);
327 return png_get_uint_16(b2);
330 #if defined PNG_READ_RGB_TO_GRAY_SUPPORTED ||\
331 defined PNG_READ_FILLER_SUPPORTED
336 randomize(b4, sizeof b4);
337 return png_get_uint_32(b4);
339 #endif /* READ_FILLER || READ_RGB_TO_GRAY */
341 #endif /* READ || WRITE_tRNS || WRITE_FILTER */
343 #if defined PNG_READ_TRANSFORMS_SUPPORTED ||\
344 defined PNG_WRITE_FILTER_SUPPORTED
346 random_mod(unsigned int max)
348 return random_u16() % max; /* 0 .. max-1 */
350 #endif /* READ_TRANSFORMS || WRITE_FILTER */
352 #if (defined PNG_READ_RGB_TO_GRAY_SUPPORTED) ||\
353 (defined PNG_READ_FILLER_SUPPORTED)
357 return random_byte() & 1;
359 #endif /* READ_RGB_TO_GRAY || READ_FILLER */
361 /* A numeric ID based on PNG file characteristics. The 'do_interlace' field
362 * simply records whether pngvalid did the interlace itself or whether it
363 * was done by libpng. Width and height must be less than 256. 'palette' is an
364 * index of the palette to use for formats with a palette otherwise a boolean
365 * indicating if a tRNS chunk was generated.
367 #define FILEID(col, depth, palette, interlace, width, height, do_interlace) \
368 ((png_uint_32)((col) + ((depth)<<3) + ((palette)<<8) + ((interlace)<<13) + \
369 (((do_interlace)!=0)<<15) + ((width)<<16) + ((height)<<24)))
371 #define COL_FROM_ID(id) ((png_byte)((id)& 0x7U))
372 #define DEPTH_FROM_ID(id) ((png_byte)(((id) >> 3) & 0x1fU))
373 #define PALETTE_FROM_ID(id) (((id) >> 8) & 0x1f)
374 #define INTERLACE_FROM_ID(id) ((png_byte)(((id) >> 13) & 0x3))
375 #define DO_INTERLACE_FROM_ID(id) ((int)(((id)>>15) & 1))
376 #define WIDTH_FROM_ID(id) (((id)>>16) & 0xff)
377 #define HEIGHT_FROM_ID(id) (((id)>>24) & 0xff)
379 /* Utility to construct a standard name for a standard image. */
381 standard_name(char *buffer, size_t bufsize, size_t pos, png_byte colour_type,
382 int bit_depth, unsigned int npalette, int interlace_type,
383 png_uint_32 w, png_uint_32 h, int do_interlace)
385 pos = safecat(buffer, bufsize, pos, colour_types[colour_type]);
386 if (colour_type == 3) /* must have a palette */
388 pos = safecat(buffer, bufsize, pos, "[");
389 pos = safecatn(buffer, bufsize, pos, npalette);
390 pos = safecat(buffer, bufsize, pos, "]");
393 else if (npalette != 0)
394 pos = safecat(buffer, bufsize, pos, "+tRNS");
396 pos = safecat(buffer, bufsize, pos, " ");
397 pos = safecatn(buffer, bufsize, pos, bit_depth);
398 pos = safecat(buffer, bufsize, pos, " bit");
400 if (interlace_type != PNG_INTERLACE_NONE)
402 pos = safecat(buffer, bufsize, pos, " interlaced");
404 pos = safecat(buffer, bufsize, pos, "(pngvalid)");
406 pos = safecat(buffer, bufsize, pos, "(libpng)");
411 pos = safecat(buffer, bufsize, pos, " ");
412 pos = safecatn(buffer, bufsize, pos, w);
413 pos = safecat(buffer, bufsize, pos, "x");
414 pos = safecatn(buffer, bufsize, pos, h);
421 standard_name_from_id(char *buffer, size_t bufsize, size_t pos, png_uint_32 id)
423 return standard_name(buffer, bufsize, pos, COL_FROM_ID(id),
424 DEPTH_FROM_ID(id), PALETTE_FROM_ID(id), INTERLACE_FROM_ID(id),
425 WIDTH_FROM_ID(id), HEIGHT_FROM_ID(id), DO_INTERLACE_FROM_ID(id));
428 /* Convenience API and defines to list valid formats. Note that 16 bit read and
429 * write support is required to do 16 bit read tests (we must be able to make a
430 * 16 bit image to test!)
432 #ifdef PNG_WRITE_16BIT_SUPPORTED
433 # define WRITE_BDHI 4
434 # ifdef PNG_READ_16BIT_SUPPORTED
439 # define WRITE_BDHI 3
445 /* The following defines the number of different palettes to generate for
446 * each log bit depth of a colour type 3 standard image.
448 #define PALETTE_COUNT(bit_depth) ((bit_depth) > 4 ? 1U : 16U)
451 next_format(png_bytep colour_type, png_bytep bit_depth,
452 unsigned int* palette_number, int low_depth_gray, int tRNS)
465 if (*colour_type < 4/*no alpha channel*/)
467 /* Add multiple palettes for colour type 3, one image with tRNS
468 * and one without for other non-alpha formats:
470 unsigned int pn = ++*palette_number;
471 png_byte ct = *colour_type;
473 if (((ct == 0/*GRAY*/ || ct/*RGB*/ == 2) && tRNS && pn < 2) ||
474 (ct == 3/*PALETTE*/ && pn < PALETTE_COUNT(*bit_depth)))
477 /* No: next bit depth */
481 *bit_depth = (png_byte)(*bit_depth << 1);
483 /* Palette images are restricted to 8 bit depth */
486 || (*colour_type != 3 && *bit_depth <= 16)
491 /* Move to the next color type, or return 0 at the end. */
492 switch (*colour_type)
519 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
521 sample(png_const_bytep row, png_byte colour_type, png_byte bit_depth,
522 png_uint_32 x, unsigned int sample_index, int swap16, int littleendian)
524 png_uint_32 bit_index, result;
526 /* Find a sample index for the desired sample: */
530 if ((colour_type & 1) == 0) /* !palette */
536 bit_index += x; /* Alpha channel */
538 /* Multiple channels; select one: */
539 if (colour_type & (2+4))
540 bit_index += sample_index * bit_depth;
543 /* Return the sample from the row as an integer. */
544 row += bit_index >> 3;
550 else if (bit_depth > 8)
553 return (*++row << 8) + result;
555 return (result << 8) + *++row;
558 /* Less than 8 bits per sample. By default PNG has the big end of
559 * the egg on the left of the screen, but if littleendian is set
560 * then the big end is on the right.
565 bit_index = 8-bit_index-bit_depth;
567 return (result >> bit_index) & ((1U<<bit_depth)-1);
569 #endif /* PNG_READ_TRANSFORMS_SUPPORTED */
571 /* Copy a single pixel, of a given size, from one buffer to another -
572 * while this is basically bit addressed there is an implicit assumption
573 * that pixels 8 or more bits in size are byte aligned and that pixels
574 * do not otherwise cross byte boundaries. (This is, so far as I know,
575 * universally true in bitmap computer graphics. [JCB 20101212])
577 * NOTE: The to and from buffers may be the same.
580 pixel_copy(png_bytep toBuffer, png_uint_32 toIndex,
581 png_const_bytep fromBuffer, png_uint_32 fromIndex, unsigned int pixelSize,
584 /* Assume we can multiply by 'size' without overflow because we are
585 * just working in a single buffer.
587 toIndex *= pixelSize;
588 fromIndex *= pixelSize;
589 if (pixelSize < 8) /* Sub-byte */
591 /* Mask to select the location of the copied pixel: */
592 unsigned int destMask = ((1U<<pixelSize)-1) <<
593 (littleendian ? toIndex&7 : 8-pixelSize-(toIndex&7));
594 /* The following read the entire pixels and clears the extra: */
595 unsigned int destByte = toBuffer[toIndex >> 3] & ~destMask;
596 unsigned int sourceByte = fromBuffer[fromIndex >> 3];
598 /* Don't rely on << or >> supporting '0' here, just in case: */
602 if (fromIndex > 0) sourceByte >>= fromIndex;
603 if ((toIndex & 7) > 0) sourceByte <<= toIndex & 7;
608 if (fromIndex > 0) sourceByte <<= fromIndex;
609 if ((toIndex & 7) > 0) sourceByte >>= toIndex & 7;
612 toBuffer[toIndex >> 3] = (png_byte)(destByte | (sourceByte & destMask));
614 else /* One or more bytes */
615 memmove(toBuffer+(toIndex>>3), fromBuffer+(fromIndex>>3), pixelSize>>3);
618 #ifdef PNG_READ_SUPPORTED
619 /* Copy a complete row of pixels, taking into account potential partial
623 row_copy(png_bytep toBuffer, png_const_bytep fromBuffer, unsigned int bitWidth,
626 memcpy(toBuffer, fromBuffer, bitWidth >> 3);
628 if ((bitWidth & 7) != 0)
632 toBuffer += bitWidth >> 3;
633 fromBuffer += bitWidth >> 3;
635 mask = 0xff << (bitWidth & 7);
637 mask = 0xff >> (bitWidth & 7);
638 *toBuffer = (png_byte)((*toBuffer & mask) | (*fromBuffer & ~mask));
642 /* Compare pixels - they are assumed to start at the first byte in the
646 pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width)
648 #if PNG_LIBPNG_VER < 10506
649 if (memcmp(pa, pb, bit_width>>3) == 0)
653 if ((bit_width & 7) == 0) return 0;
655 /* Ok, any differences? */
656 p = pa[bit_width >> 3];
657 p ^= pb[bit_width >> 3];
659 if (p == 0) return 0;
661 /* There are, but they may not be significant, remove the bits
662 * after the end (the low order bits in PNG.)
667 if (p == 0) return 0;
670 /* From libpng-1.5.6 the overwrite should be fixed, so compare the trailing
673 if (memcmp(pa, pb, (bit_width+7)>>3) == 0)
677 /* Return the index of the changed byte. */
679 png_uint_32 where = 0;
681 while (pa[where] == pb[where]) ++where;
685 #endif /* PNG_READ_SUPPORTED */
687 /*************************** BASIC PNG FILE WRITING ***************************/
688 /* A png_store takes data from the sequential writer or provides data
689 * to the sequential reader. It can also store the result of a PNG
690 * write for later retrieval.
692 #define STORE_BUFFER_SIZE 500 /* arbitrary */
693 typedef struct png_store_buffer
695 struct png_store_buffer* prev; /* NOTE: stored in reverse order */
696 png_byte buffer[STORE_BUFFER_SIZE];
699 #define FILE_NAME_SIZE 64
701 typedef struct store_palette_entry /* record of a single palette entry */
707 } store_palette_entry, store_palette[256];
709 typedef struct png_store_file
711 struct png_store_file* next; /* as many as you like... */
712 char name[FILE_NAME_SIZE];
713 unsigned int IDAT_bits; /* Number of bits in IDAT size */
714 png_uint_32 IDAT_size; /* Total size of IDAT data */
715 png_uint_32 id; /* must be correct (see FILEID) */
716 size_t datacount; /* In this (the last) buffer */
717 png_store_buffer data; /* Last buffer in file */
718 int npalette; /* Number of entries in palette */
719 store_palette_entry* palette; /* May be NULL */
722 /* The following is a pool of memory allocated by a single libpng read or write
725 typedef struct store_pool
727 struct png_store *store; /* Back pointer */
728 struct store_memory *list; /* List of allocated memory */
729 png_byte mark[4]; /* Before and after data */
731 /* Statistics for this run. */
732 png_alloc_size_t max; /* Maximum single allocation */
733 png_alloc_size_t current; /* Current allocation */
734 png_alloc_size_t limit; /* Highest current allocation */
735 png_alloc_size_t total; /* Total allocation */
737 /* Overall statistics (retained across successive runs). */
738 png_alloc_size_t max_max;
739 png_alloc_size_t max_limit;
740 png_alloc_size_t max_total;
743 typedef struct png_store
745 /* For cexcept.h exception handling - simply store one of these;
746 * the context is a self pointer but it may point to a different
747 * png_store (in fact it never does in this program.)
749 struct exception_context
752 unsigned int verbose :1;
753 unsigned int treat_warnings_as_errors :1;
754 unsigned int expect_error :1;
755 unsigned int expect_warning :1;
756 unsigned int saw_warning :1;
757 unsigned int speed :1;
758 unsigned int progressive :1; /* use progressive read */
759 unsigned int validated :1; /* used as a temporary flag */
762 int noptions; /* number of options below: */
764 unsigned char option; /* option number, 0..30 */
765 unsigned char setting; /* setting (unset,invalid,on,off) */
767 char test[128]; /* Name of test */
771 png_uint_32 chunklen; /* Length of chunk+overhead (chunkpos >= 8) */
772 png_uint_32 chunktype;/* Type of chunk (valid if chunkpos >= 4) */
773 png_uint_32 chunkpos; /* Position in chunk */
774 png_uint_32 IDAT_size;/* Accumulated IDAT size in .new */
775 unsigned int IDAT_bits;/* Cache of the file store value */
778 png_structp pread; /* Used to read a saved file */
780 png_store_file* current; /* Set when reading */
781 png_store_buffer* next; /* Set when reading */
782 size_t readpos; /* Position in *next */
783 png_byte* image; /* Buffer for reading interlaced images */
784 size_t cb_image; /* Size of this buffer */
785 size_t cb_row; /* Row size of the image(s) */
787 png_uint_32 IDAT_len; /* Used when re-chunking IDAT chunks */
788 png_uint_32 IDAT_pos; /* Used when re-chunking IDAT chunks */
789 png_uint_32 image_h; /* Number of rows in a single image */
790 store_pool read_memory_pool;
793 png_store_file* saved;
794 png_structp pwrite; /* Used when writing a new file */
796 size_t writepos; /* Position in .new */
797 char wname[FILE_NAME_SIZE];
798 png_store_buffer new; /* The end of the new PNG file being written. */
799 store_pool write_memory_pool;
800 store_palette_entry* palette;
804 /* Initialization and cleanup */
806 store_pool_mark(png_bytep mark)
808 static png_uint_32 store_seed[2] = { 0x12345678, 1};
810 make_four_random_bytes(store_seed, mark);
813 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
814 /* Use this for random 32 bit values; this function makes sure the result is
826 store_pool_mark(mark);
827 result = png_get_uint_32(mark);
833 #endif /* PNG_READ_SUPPORTED */
836 store_pool_init(png_store *ps, store_pool *pool)
838 memset(pool, 0, sizeof *pool);
842 pool->max = pool->current = pool->limit = pool->total = 0;
843 pool->max_max = pool->max_limit = pool->max_total = 0;
844 store_pool_mark(pool->mark);
848 store_init(png_store* ps)
850 memset(ps, 0, sizeof *ps);
851 init_exception_context(&ps->exception_context);
852 store_pool_init(ps, &ps->read_memory_pool);
853 store_pool_init(ps, &ps->write_memory_pool);
855 ps->treat_warnings_as_errors = 0;
856 ps->expect_error = 0;
857 ps->expect_warning = 0;
862 ps->nerrors = ps->nwarnings = 0;
865 ps->saved = ps->current = NULL;
887 store_freebuffer(png_store_buffer* psb)
891 store_freebuffer(psb->prev);
898 store_freenew(png_store *ps)
900 store_freebuffer(&ps->new);
907 if (ps->palette != NULL)
916 store_storenew(png_store *ps)
918 png_store_buffer *pb;
920 pb = voidcast(png_store_buffer*, malloc(sizeof *pb));
923 png_error(ps->pwrite, "store new: OOM");
931 store_freefile(png_store_file **ppf)
935 store_freefile(&(*ppf)->next);
937 store_freebuffer(&(*ppf)->data);
938 (*ppf)->datacount = 0;
939 if ((*ppf)->palette != NULL)
941 free((*ppf)->palette);
942 (*ppf)->palette = NULL;
943 (*ppf)->npalette = 0;
951 bits_of(png_uint_32 num)
953 /* Return the number of bits in 'num' */
956 if (num & 0xffff0000U) b += 16U, num >>= 16;
957 if (num & 0xff00U) b += 8U, num >>= 8;
958 if (num & 0xf0U) b += 4U, num >>= 4;
959 if (num & 0xcU) b += 2U, num >>= 2;
960 if (num & 0x2U) ++b, num >>= 1;
963 return b; /* 0..32 */
966 /* Main interface to file storage, after writing a new PNG file (see the API
967 * below) call store_storefile to store the result with the given name and id.
970 store_storefile(png_store *ps, png_uint_32 id)
974 if (ps->chunkpos != 0U || ps->chunktype != 0U || ps->chunklen != 0U ||
976 png_error(ps->pwrite, "storefile: incomplete write");
978 pf = voidcast(png_store_file*, malloc(sizeof *pf));
980 png_error(ps->pwrite, "storefile: OOM");
981 safecat(pf->name, sizeof pf->name, 0, ps->wname);
984 pf->datacount = ps->writepos;
985 pf->IDAT_size = ps->IDAT_size;
986 pf->IDAT_bits = bits_of(ps->IDAT_size);
987 /* Because the IDAT always has zlib header stuff this must be true: */
988 if (pf->IDAT_bits == 0U)
989 png_error(ps->pwrite, "storefile: 0 sized IDAT");
996 pf->palette = ps->palette;
997 pf->npalette = ps->npalette;
1002 pf->next = ps->saved;
1006 /* Generate an error message (in the given buffer) */
1008 store_message(png_store *ps, png_const_structp pp, char *buffer, size_t bufsize,
1009 size_t pos, const char *msg)
1011 if (pp != NULL && pp == ps->pread)
1013 /* Reading a file */
1014 pos = safecat(buffer, bufsize, pos, "read: ");
1016 if (ps->current != NULL)
1018 pos = safecat(buffer, bufsize, pos, ps->current->name);
1019 pos = safecat(buffer, bufsize, pos, sep);
1023 else if (pp != NULL && pp == ps->pwrite)
1025 /* Writing a file */
1026 pos = safecat(buffer, bufsize, pos, "write: ");
1027 pos = safecat(buffer, bufsize, pos, ps->wname);
1028 pos = safecat(buffer, bufsize, pos, sep);
1033 /* Neither reading nor writing (or a memory error in struct delete) */
1034 pos = safecat(buffer, bufsize, pos, "pngvalid: ");
1037 if (ps->test[0] != 0)
1039 pos = safecat(buffer, bufsize, pos, ps->test);
1040 pos = safecat(buffer, bufsize, pos, sep);
1042 pos = safecat(buffer, bufsize, pos, msg);
1046 /* Verbose output to the error stream: */
1048 store_verbose(png_store *ps, png_const_structp pp, png_const_charp prefix,
1049 png_const_charp message)
1054 fputs(prefix, stderr);
1056 (void)store_message(ps, pp, buffer, sizeof buffer, 0, message);
1057 fputs(buffer, stderr);
1058 fputc('\n', stderr);
1061 /* Log an error or warning - the relevant count is always incremented. */
1063 store_log(png_store* ps, png_const_structp pp, png_const_charp message,
1066 /* The warning is copied to the error buffer if there are no errors and it is
1067 * the first warning. The error is copied to the error buffer if it is the
1068 * first error (overwriting any prior warnings).
1070 if (is_error ? (ps->nerrors)++ == 0 :
1071 (ps->nwarnings)++ == 0 && ps->nerrors == 0)
1072 store_message(ps, pp, ps->error, sizeof ps->error, 0, message);
1075 store_verbose(ps, pp, is_error ? "error: " : "warning: ", message);
1078 #ifdef PNG_READ_SUPPORTED
1079 /* Internal error function, called with a png_store but no libpng stuff. */
1081 internal_error(png_store *ps, png_const_charp message)
1083 store_log(ps, NULL, message, 1 /* error */);
1085 /* And finally throw an exception. */
1087 struct exception_context *the_exception_context = &ps->exception_context;
1091 #endif /* PNG_READ_SUPPORTED */
1093 /* Functions to use as PNG callbacks. */
1094 static void PNGCBAPI
1095 store_error(png_structp ppIn, png_const_charp message) /* PNG_NORETURN */
1097 png_const_structp pp = ppIn;
1098 png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
1100 if (!ps->expect_error)
1101 store_log(ps, pp, message, 1 /* error */);
1103 /* And finally throw an exception. */
1105 struct exception_context *the_exception_context = &ps->exception_context;
1110 static void PNGCBAPI
1111 store_warning(png_structp ppIn, png_const_charp message)
1113 png_const_structp pp = ppIn;
1114 png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
1116 if (!ps->expect_warning)
1117 store_log(ps, pp, message, 0 /* warning */);
1119 ps->saw_warning = 1;
1122 /* These somewhat odd functions are used when reading an image to ensure that
1123 * the buffer is big enough, the png_structp is for errors.
1125 /* Return a single row from the correct image. */
1127 store_image_row(const png_store* ps, png_const_structp pp, int nImage,
1130 size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2;
1132 if (ps->image == NULL)
1133 png_error(pp, "no allocated image");
1135 if (coffset + ps->cb_row + 3 > ps->cb_image)
1136 png_error(pp, "image too small");
1138 return ps->image + coffset;
1142 store_image_free(png_store *ps, png_const_structp pp)
1144 if (ps->image != NULL)
1146 png_bytep image = ps->image;
1148 if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
1151 png_error(pp, "png_store image overwrite (1)");
1153 store_log(ps, NULL, "png_store image overwrite (2)", 1);
1164 store_ensure_image(png_store *ps, png_const_structp pp, int nImages,
1165 size_t cbRow, png_uint_32 cRows)
1167 size_t cb = nImages * cRows * (cbRow + 5);
1169 if (ps->cb_image < cb)
1173 store_image_free(ps, pp);
1175 /* The buffer is deliberately mis-aligned. */
1176 image = voidcast(png_bytep, malloc(cb+2));
1179 /* Called from the startup - ignore the error for the moment. */
1183 png_error(pp, "OOM allocating image buffer");
1186 /* These magic tags are used to detect overwrites above. */
1195 /* We have an adequate sized image; lay out the rows. There are 2 bytes at
1196 * the start and three at the end of each (this ensures that the row
1197 * alignment starts out odd - 2+1 and changes for larger images on each row.)
1200 ps->image_h = cRows;
1202 /* For error checking, the whole buffer is set to 10110010 (0xb2 - 178).
1203 * This deliberately doesn't match the bits in the size test image which are
1204 * outside the image; these are set to 0xff (all 1). To make the row
1205 * comparison work in the 'size' test case the size rows are pre-initialized
1206 * to the same value prior to calling 'standard_row'.
1208 memset(ps->image, 178, cb);
1210 /* Then put in the marks. */
1211 while (--nImages >= 0)
1215 for (y=0; y<cRows; ++y)
1217 png_bytep row = store_image_row(ps, pp, nImages, y);
1229 #ifdef PNG_READ_SUPPORTED
1231 store_image_check(const png_store* ps, png_const_structp pp, int iImage)
1233 png_const_bytep image = ps->image;
1235 if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
1236 png_error(pp, "image overwrite");
1239 size_t cbRow = ps->cb_row;
1240 png_uint_32 rows = ps->image_h;
1242 image += iImage * (cbRow+5) * ps->image_h;
1244 image += 2; /* skip image first row markers */
1246 for (; rows > 0; --rows)
1248 if (image[-2] != 190 || image[-1] != 239)
1249 png_error(pp, "row start overwritten");
1251 if (image[cbRow] != 222 || image[cbRow+1] != 173 ||
1252 image[cbRow+2] != 17)
1253 png_error(pp, "row end overwritten");
1259 #endif /* PNG_READ_SUPPORTED */
1262 valid_chunktype(png_uint_32 chunktype)
1264 /* Each byte in the chunk type must be in one of the ranges 65..90, 97..122
1265 * (both inclusive), so:
1271 unsigned int c = chunktype & 0xffU;
1273 if (!((c >= 65U && c <= 90U) || (c >= 97U && c <= 122U)))
1279 return 1; /* It's valid */
1282 static void PNGCBAPI
1283 store_write(png_structp ppIn, png_bytep pb, size_t st)
1285 png_const_structp pp = ppIn;
1286 png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
1287 size_t writepos = ps->writepos;
1288 png_uint_32 chunkpos = ps->chunkpos;
1289 png_uint_32 chunktype = ps->chunktype;
1290 png_uint_32 chunklen = ps->chunklen;
1292 if (ps->pwrite != pp)
1293 png_error(pp, "store state damaged");
1295 /* Technically this is legal, but in practice libpng never writes more than
1296 * the maximum chunk size at once so if it happens something weird has
1297 * changed inside libpng (probably).
1299 if (st > 0x7fffffffU)
1300 png_error(pp, "unexpected write size");
1302 /* Now process the bytes to be written. Do this in units of the space in the
1303 * output (write) buffer or, at the start 4 bytes for the chunk type and
1304 * length limited in any case by the amount of data.
1308 if (writepos >= STORE_BUFFER_SIZE)
1309 store_storenew(ps), writepos = 0;
1315 chunklen = (chunklen << 8) + b;
1316 ps->new.buffer[writepos++] = b;
1320 else if (chunkpos < 8)
1324 chunktype = (chunktype << 8) + b;
1325 ps->new.buffer[writepos++] = b;
1327 if (++chunkpos == 8)
1329 chunklen &= 0xffffffffU;
1330 if (chunklen > 0x7fffffffU)
1331 png_error(pp, "chunk length too great");
1333 chunktype &= 0xffffffffU;
1334 if (chunktype == CHUNK_IDAT)
1336 if (chunklen > ~ps->IDAT_size)
1337 png_error(pp, "pngvalid internal image too large");
1339 ps->IDAT_size += chunklen;
1342 else if (!valid_chunktype(chunktype))
1343 png_error(pp, "invalid chunk type");
1345 chunklen += 12; /* for header and CRC */
1349 else /* chunkpos >= 8 */
1353 if (cb > STORE_BUFFER_SIZE - writepos)
1354 cb = STORE_BUFFER_SIZE - writepos;
1356 if (cb > chunklen - chunkpos/* bytes left in chunk*/)
1357 cb = (size_t)/*SAFE*/(chunklen - chunkpos);
1359 memcpy(ps->new.buffer + writepos, pb, cb);
1360 chunkpos += (png_uint_32)/*SAFE*/cb;
1365 if (chunkpos >= chunklen) /* must be equal */
1366 chunkpos = chunktype = chunklen = 0;
1368 } /* while (st > 0) */
1370 ps->writepos = writepos;
1371 ps->chunkpos = chunkpos;
1372 ps->chunktype = chunktype;
1373 ps->chunklen = chunklen;
1376 static void PNGCBAPI
1377 store_flush(png_structp ppIn)
1379 UNUSED(ppIn) /*DOES NOTHING*/
1382 #ifdef PNG_READ_SUPPORTED
1384 store_read_buffer_size(png_store *ps)
1386 /* Return the bytes available for read in the current buffer. */
1387 if (ps->next != &ps->current->data)
1388 return STORE_BUFFER_SIZE;
1390 return ps->current->datacount;
1393 /* Return total bytes available for read. */
1395 store_read_buffer_avail(png_store *ps)
1397 if (ps->current != NULL && ps->next != NULL)
1399 png_store_buffer *next = &ps->current->data;
1400 size_t cbAvail = ps->current->datacount;
1402 while (next != ps->next && next != NULL)
1405 cbAvail += STORE_BUFFER_SIZE;
1408 if (next != ps->next)
1409 png_error(ps->pread, "buffer read error");
1411 if (cbAvail > ps->readpos)
1412 return cbAvail - ps->readpos;
1419 store_read_buffer_next(png_store *ps)
1421 png_store_buffer *pbOld = ps->next;
1422 png_store_buffer *pbNew = &ps->current->data;
1425 while (pbNew != NULL && pbNew->prev != pbOld)
1426 pbNew = pbNew->prev;
1435 png_error(ps->pread, "buffer lost");
1438 return 0; /* EOF or error */
1441 /* Need separate implementation and callback to allow use of the same code
1442 * during progressive read, where the io_ptr is set internally by libpng.
1445 store_read_imp(png_store *ps, png_bytep pb, size_t st)
1447 if (ps->current == NULL || ps->next == NULL)
1448 png_error(ps->pread, "store state damaged");
1452 size_t cbAvail = store_read_buffer_size(ps) - ps->readpos;
1456 if (cbAvail > st) cbAvail = st;
1457 memcpy(pb, ps->next->buffer + ps->readpos, cbAvail);
1460 ps->readpos += cbAvail;
1463 else if (!store_read_buffer_next(ps))
1464 png_error(ps->pread, "read beyond end of file");
1469 store_read_chunk(png_store *ps, png_bytep pb, size_t max, size_t min)
1471 png_uint_32 chunklen = ps->chunklen;
1472 png_uint_32 chunktype = ps->chunktype;
1473 png_uint_32 chunkpos = ps->chunkpos;
1478 if (chunkpos >= chunklen) /* end of last chunk */
1482 /* Read the header of the next chunk: */
1483 store_read_imp(ps, buffer, 8U);
1484 chunklen = png_get_uint_32(buffer) + 12U;
1485 chunktype = png_get_uint_32(buffer+4U);
1486 chunkpos = 0U; /* Position read so far */
1489 if (chunktype == CHUNK_IDAT)
1491 png_uint_32 IDAT_pos = ps->IDAT_pos;
1492 png_uint_32 IDAT_len = ps->IDAT_len;
1493 png_uint_32 IDAT_size = ps->IDAT_size;
1495 /* The IDAT headers are constructed here; skip the input header. */
1499 if (IDAT_pos == IDAT_len)
1501 png_byte random = random_byte();
1503 /* Make a new IDAT chunk, if IDAT_len is 0 this is the first IDAT,
1504 * if IDAT_size is 0 this is the end. At present this is set up
1505 * using a random number so that there is a 25% chance before
1506 * the start of the first IDAT chunk being 0 length.
1508 if (IDAT_len == 0U) /* First IDAT */
1510 switch (random & 3U)
1512 case 0U: IDAT_len = 12U; break; /* 0 bytes */
1513 case 1U: IDAT_len = 13U; break; /* 1 byte */
1514 default: IDAT_len = random_u32();
1515 IDAT_len %= IDAT_size;
1516 IDAT_len += 13U; /* 1..IDAT_size bytes */
1521 else if (IDAT_size == 0U) /* all IDAT data read */
1523 /* The last (IDAT) chunk should be positioned at the CRC now: */
1524 if (chunkpos != chunklen-4U)
1525 png_error(ps->pread, "internal: IDAT size mismatch");
1527 /* The only option here is to add a zero length IDAT, this
1528 * happens 25% of the time. Because of the check above
1529 * chunklen-4U-chunkpos must be zero, we just need to skip the
1532 if ((random & 3U) == 0U)
1533 IDAT_len = 12U; /* Output another 0 length IDAT */
1537 /* End of IDATs, skip the CRC to make the code above load the
1538 * next chunk header next time round.
1542 store_read_imp(ps, buffer, 4U);
1544 ps->IDAT_pos = IDAT_pos;
1545 ps->IDAT_len = IDAT_len;
1547 continue; /* Read the next chunk */
1553 /* Middle of IDATs, use 'random' to determine the number of bits
1554 * to use in the IDAT length.
1556 IDAT_len = random_u32();
1557 IDAT_len &= (1U << (1U + random % ps->IDAT_bits)) - 1U;
1558 if (IDAT_len > IDAT_size)
1559 IDAT_len = IDAT_size;
1560 IDAT_len += 12U; /* zero bytes may occur */
1564 ps->IDAT_crc = 0x35af061e; /* Ie: crc32(0UL, "IDAT", 4) */
1565 } /* IDAT_pos == IDAT_len */
1567 if (IDAT_pos < 8U) /* Return the header */ do
1578 shift = 3U & IDAT_pos;
1582 b >>= 8U*(3U-shift);
1586 while (--st > 0 && IDAT_pos < 8);
1588 else if (IDAT_pos < IDAT_len - 4U) /* I.e not the CRC */
1590 if (chunkpos < chunklen-4U)
1592 uInt avail = (uInt)-1;
1594 if (avail > (IDAT_len-4U) - IDAT_pos)
1595 avail = (uInt)/*SAFE*/((IDAT_len-4U) - IDAT_pos);
1598 avail = (uInt)/*SAFE*/st;
1600 if (avail > (chunklen-4U) - chunkpos)
1601 avail = (uInt)/*SAFE*/((chunklen-4U) - chunkpos);
1603 store_read_imp(ps, pb, avail);
1604 ps->IDAT_crc = crc32(ps->IDAT_crc, pb, avail);
1605 pb += (size_t)/*SAFE*/avail;
1606 st -= (size_t)/*SAFE*/avail;
1607 chunkpos += (png_uint_32)/*SAFE*/avail;
1608 IDAT_size -= (png_uint_32)/*SAFE*/avail;
1609 IDAT_pos += (png_uint_32)/*SAFE*/avail;
1612 else /* skip the input CRC */
1616 store_read_imp(ps, buffer, 4U);
1621 else /* IDAT crc */ do
1623 uLong b = ps->IDAT_crc;
1624 unsigned int shift = (IDAT_len - IDAT_pos); /* 4..1 */
1628 b >>= 8U*(shift-1U);
1632 while (--st > 0 && IDAT_pos < IDAT_len);
1634 ps->IDAT_pos = IDAT_pos;
1635 ps->IDAT_len = IDAT_len;
1636 ps->IDAT_size = IDAT_size;
1641 /* If there is still some pending IDAT data after the IDAT chunks have
1642 * been processed there is a problem:
1644 if (ps->IDAT_len > 0 && ps->IDAT_size > 0)
1645 png_error(ps->pread, "internal: missing IDAT data");
1647 if (chunktype == CHUNK_IEND && ps->IDAT_len == 0U)
1648 png_error(ps->pread, "internal: missing IDAT");
1650 if (chunkpos < 8U) /* Return the header */ do
1661 shift = 3U & chunkpos;
1665 b >>= 8U*(3U-shift);
1669 while (--st > 0 && chunkpos < 8);
1671 else /* Return chunk bytes, including the CRC */
1675 if (avail > chunklen - chunkpos)
1676 avail = (size_t)/*SAFE*/(chunklen - chunkpos);
1678 store_read_imp(ps, pb, avail);
1681 chunkpos += (png_uint_32)/*SAFE*/avail;
1683 /* Check for end of chunk and end-of-file; don't try to read a new
1684 * chunk header at this point unless instructed to do so by 'min'.
1686 if (chunkpos >= chunklen && max-st >= min &&
1687 store_read_buffer_avail(ps) == 0)
1694 ps->chunklen = chunklen;
1695 ps->chunktype = chunktype;
1696 ps->chunkpos = chunkpos;
1698 return st; /* space left */
1701 static void PNGCBAPI
1702 store_read(png_structp ppIn, png_bytep pb, size_t st)
1704 png_const_structp pp = ppIn;
1705 png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
1707 if (ps == NULL || ps->pread != pp)
1708 png_error(pp, "bad store read call");
1710 store_read_chunk(ps, pb, st, st);
1714 store_progressive_read(png_store *ps, png_structp pp, png_infop pi)
1716 if (ps->pread != pp || ps->current == NULL || ps->next == NULL)
1717 png_error(pp, "store state damaged (progressive)");
1719 /* This is another Horowitz and Hill random noise generator. In this case
1720 * the aim is to stress the progressive reader with truly horrible variable
1721 * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
1722 * is generated. We could probably just count from 1 to 32767 and get as
1725 while (store_read_buffer_avail(ps) > 0)
1727 static png_uint_32 noise = 2;
1729 png_byte buffer[512];
1731 /* Generate 15 more bits of stuff: */
1732 noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
1734 cb -= store_read_chunk(ps, buffer, cb, 1);
1735 png_process_data(pp, pi, buffer, cb);
1738 #endif /* PNG_READ_SUPPORTED */
1740 /* The caller must fill this in: */
1741 static store_palette_entry *
1742 store_write_palette(png_store *ps, int npalette)
1744 if (ps->pwrite == NULL)
1745 store_log(ps, NULL, "attempt to write palette without write stream", 1);
1747 if (ps->palette != NULL)
1748 png_error(ps->pwrite, "multiple store_write_palette calls");
1750 /* This function can only return NULL if called with '0'! */
1753 ps->palette = voidcast(store_palette_entry*, malloc(npalette *
1754 sizeof *ps->palette));
1756 if (ps->palette == NULL)
1757 png_error(ps->pwrite, "store new palette: OOM");
1759 ps->npalette = npalette;
1765 #ifdef PNG_READ_SUPPORTED
1766 static store_palette_entry *
1767 store_current_palette(png_store *ps, int *npalette)
1769 /* This is an internal error (the call has been made outside a read
1772 if (ps->current == NULL)
1774 store_log(ps, ps->pread, "no current stream for palette", 1);
1778 /* The result may be null if there is no palette. */
1779 *npalette = ps->current->npalette;
1780 return ps->current->palette;
1782 #endif /* PNG_READ_SUPPORTED */
1784 /***************************** MEMORY MANAGEMENT*** ***************************/
1785 #ifdef PNG_USER_MEM_SUPPORTED
1786 /* A store_memory is simply the header for an allocated block of memory. The
1787 * pointer returned to libpng is just after the end of the header block, the
1788 * allocated memory is followed by a second copy of the 'mark'.
1790 typedef struct store_memory
1792 store_pool *pool; /* Originating pool */
1793 struct store_memory *next; /* Singly linked list */
1794 png_alloc_size_t size; /* Size of memory allocated */
1795 png_byte mark[4]; /* ID marker */
1798 /* Handle a fatal error in memory allocation. This calls png_error if the
1799 * libpng struct is non-NULL, else it outputs a message and returns. This means
1800 * that a memory problem while libpng is running will abort (png_error) the
1801 * handling of particular file while one in cleanup (after the destroy of the
1802 * struct has returned) will simply keep going and free (or attempt to free)
1806 store_pool_error(png_store *ps, png_const_structp pp, const char *msg)
1811 /* Else we have to do it ourselves. png_error eventually calls store_log,
1812 * above. store_log accepts a NULL png_structp - it just changes what gets
1813 * output by store_message.
1815 store_log(ps, pp, msg, 1 /* error */);
1819 store_memory_free(png_const_structp pp, store_pool *pool, store_memory *memory)
1821 /* Note that pp may be NULL (see store_pool_delete below), the caller has
1822 * found 'memory' in pool->list *and* unlinked this entry, so this is a valid
1823 * pointer (for sure), but the contents may have been trashed.
1825 if (memory->pool != pool)
1826 store_pool_error(pool->store, pp, "memory corrupted (pool)");
1828 else if (memcmp(memory->mark, pool->mark, sizeof memory->mark) != 0)
1829 store_pool_error(pool->store, pp, "memory corrupted (start)");
1831 /* It should be safe to read the size field now. */
1834 png_alloc_size_t cb = memory->size;
1837 store_pool_error(pool->store, pp, "memory corrupted (size)");
1839 else if (memcmp((png_bytep)(memory+1)+cb, pool->mark, sizeof pool->mark)
1841 store_pool_error(pool->store, pp, "memory corrupted (end)");
1843 /* Finally give the library a chance to find problems too: */
1846 pool->current -= cb;
1853 store_pool_delete(png_store *ps, store_pool *pool)
1855 if (pool->list != NULL)
1857 fprintf(stderr, "%s: %s %s: memory lost (list follows):\n", ps->test,
1858 pool == &ps->read_memory_pool ? "read" : "write",
1859 pool == &ps->read_memory_pool ? (ps->current != NULL ?
1860 ps->current->name : "unknown file") : ps->wname);
1865 store_memory *next = pool->list;
1866 pool->list = next->next;
1869 fprintf(stderr, "\t%lu bytes @ %p\n",
1870 (unsigned long)next->size, (const void*)(next+1));
1871 /* The NULL means this will always return, even if the memory is
1874 store_memory_free(NULL, pool, next);
1876 while (pool->list != NULL);
1879 /* And reset the other fields too for the next time. */
1880 if (pool->max > pool->max_max) pool->max_max = pool->max;
1882 if (pool->current != 0) /* unexpected internal error */
1883 fprintf(stderr, "%s: %s %s: memory counter mismatch (internal error)\n",
1884 ps->test, pool == &ps->read_memory_pool ? "read" : "write",
1885 pool == &ps->read_memory_pool ? (ps->current != NULL ?
1886 ps->current->name : "unknown file") : ps->wname);
1889 if (pool->limit > pool->max_limit)
1890 pool->max_limit = pool->limit;
1894 if (pool->total > pool->max_total)
1895 pool->max_total = pool->total;
1899 /* Get a new mark too. */
1900 store_pool_mark(pool->mark);
1903 /* The memory callbacks: */
1904 static png_voidp PNGCBAPI
1905 store_malloc(png_structp ppIn, png_alloc_size_t cb)
1907 png_const_structp pp = ppIn;
1908 store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
1909 store_memory *new = voidcast(store_memory*, malloc(cb + (sizeof *new) +
1910 (sizeof pool->mark)));
1917 pool->current += cb;
1919 if (pool->current > pool->limit)
1920 pool->limit = pool->current;
1925 memcpy(new->mark, pool->mark, sizeof new->mark);
1926 memcpy((png_byte*)(new+1) + cb, pool->mark, sizeof pool->mark);
1928 new->next = pool->list;
1935 /* NOTE: the PNG user malloc function cannot use the png_ptr it is passed
1936 * other than to retrieve the allocation pointer! libpng calls the
1937 * store_malloc callback in two basic cases:
1939 * 1) From png_malloc; png_malloc will do a png_error itself if NULL is
1941 * 2) From png_struct or png_info structure creation; png_malloc is
1942 * to return so cleanup can be performed.
1944 * To handle this store_malloc can log a message, but can't do anything
1947 store_log(pool->store, pp, "out of memory", 1 /* is_error */);
1953 static void PNGCBAPI
1954 store_free(png_structp ppIn, png_voidp memory)
1956 png_const_structp pp = ppIn;
1957 store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
1958 store_memory *this = voidcast(store_memory*, memory), **test;
1960 /* Because libpng calls store_free with a dummy png_struct when deleting
1961 * png_struct or png_info via png_destroy_struct_2 it is necessary to check
1962 * the passed in png_structp to ensure it is valid, and not pass it to
1963 * png_error if it is not.
1965 if (pp != pool->store->pread && pp != pool->store->pwrite)
1968 /* First check that this 'memory' really is valid memory - it must be in the
1969 * pool list. If it is, use the shared memory_free function to free it.
1972 for (test = &pool->list; *test != this; test = &(*test)->next)
1976 store_pool_error(pool->store, pp, "bad pointer to free");
1981 /* Unlink this entry, *test == this. */
1984 store_memory_free(pp, pool, this);
1986 #endif /* PNG_USER_MEM_SUPPORTED */
1988 /* Setup functions. */
1989 /* Cleanup when aborting a write or after storing the new file. */
1991 store_write_reset(png_store *ps)
1993 if (ps->pwrite != NULL)
1998 png_destroy_write_struct(&ps->pwrite, &ps->piwrite);
2002 /* memory corruption: continue. */
2009 /* And make sure that all the memory has been freed - this will output
2010 * spurious errors in the case of memory corruption above, but this is safe.
2012 # ifdef PNG_USER_MEM_SUPPORTED
2013 store_pool_delete(ps, &ps->write_memory_pool);
2019 /* The following is the main write function, it returns a png_struct and,
2020 * optionally, a png_info suitable for writiing a new PNG file. Use
2021 * store_storefile above to record this file after it has been written. The
2022 * returned libpng structures as destroyed by store_write_reset above.
2025 set_store_for_write(png_store *ps, png_infopp ppi, const char *name)
2031 if (ps->pwrite != NULL)
2032 png_error(ps->pwrite, "write store already in use");
2034 store_write_reset(ps);
2035 safecat(ps->wname, sizeof ps->wname, 0, name);
2037 /* Don't do the slow memory checks if doing a speed test, also if user
2038 * memory is not supported we can't do it anyway.
2040 # ifdef PNG_USER_MEM_SUPPORTED
2042 ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING,
2043 ps, store_error, store_warning, &ps->write_memory_pool,
2044 store_malloc, store_free);
2048 ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
2049 ps, store_error, store_warning);
2051 png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
2053 # ifdef PNG_SET_OPTION_SUPPORTED
2056 for (opt=0; opt<ps->noptions; ++opt)
2057 if (png_set_option(ps->pwrite, ps->options[opt].option,
2058 ps->options[opt].setting) == PNG_OPTION_INVALID)
2059 png_error(ps->pwrite, "png option invalid");
2064 *ppi = ps->piwrite = png_create_info_struct(ps->pwrite);
2073 /* Cleanup when finished reading (either due to error or in the success case).
2074 * This routine exists even when there is no read support to make the code
2075 * tidier (avoid a mass of ifdefs) and so easier to maintain.
2078 store_read_reset(png_store *ps)
2080 # ifdef PNG_READ_SUPPORTED
2081 if (ps->pread != NULL)
2086 png_destroy_read_struct(&ps->pread, &ps->piread, NULL);
2090 /* error already output: continue */
2098 # ifdef PNG_USER_MEM_SUPPORTED
2099 /* Always do this to be safe. */
2100 store_pool_delete(ps, &ps->read_memory_pool);
2114 #ifdef PNG_READ_SUPPORTED
2116 store_read_set(png_store *ps, png_uint_32 id)
2118 png_store_file *pf = ps->saved;
2126 ps->IDAT_size = pf->IDAT_size;
2127 ps->IDAT_bits = pf->IDAT_bits; /* just a cache */
2131 store_read_buffer_next(ps);
2140 char msg[FILE_NAME_SIZE+64];
2142 pos = standard_name_from_id(msg, sizeof msg, 0, id);
2143 pos = safecat(msg, sizeof msg, pos, ": file not found");
2144 png_error(ps->pread, msg);
2148 /* The main interface for reading a saved file - pass the id number of the file
2149 * to retrieve. Ids must be unique or the earlier file will be hidden. The API
2150 * returns a png_struct and, optionally, a png_info. Both of these will be
2151 * destroyed by store_read_reset above.
2154 set_store_for_read(png_store *ps, png_infopp ppi, png_uint_32 id,
2157 /* Set the name for png_error */
2158 safecat(ps->test, sizeof ps->test, 0, name);
2160 if (ps->pread != NULL)
2161 png_error(ps->pread, "read store already in use");
2163 store_read_reset(ps);
2165 /* Both the create APIs can return NULL if used in their default mode
2166 * (because there is no other way of handling an error because the jmp_buf
2167 * by default is stored in png_struct and that has not been allocated!)
2168 * However, given that store_error works correctly in these circumstances
2169 * we don't ever expect NULL in this program.
2171 # ifdef PNG_USER_MEM_SUPPORTED
2173 ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps,
2174 store_error, store_warning, &ps->read_memory_pool, store_malloc,
2179 ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps, store_error,
2182 if (ps->pread == NULL)
2184 struct exception_context *the_exception_context = &ps->exception_context;
2186 store_log(ps, NULL, "png_create_read_struct returned NULL (unexpected)",
2192 # ifdef PNG_SET_OPTION_SUPPORTED
2195 for (opt=0; opt<ps->noptions; ++opt)
2196 if (png_set_option(ps->pread, ps->options[opt].option,
2197 ps->options[opt].setting) == PNG_OPTION_INVALID)
2198 png_error(ps->pread, "png option invalid");
2202 store_read_set(ps, id);
2205 *ppi = ps->piread = png_create_info_struct(ps->pread);
2209 #endif /* PNG_READ_SUPPORTED */
2211 /* The overall cleanup of a store simply calls the above then removes all the
2212 * saved files. This does not delete the store itself.
2215 store_delete(png_store *ps)
2217 store_write_reset(ps);
2218 store_read_reset(ps);
2219 store_freefile(&ps->saved);
2220 store_image_free(ps, NULL);
2223 /*********************** PNG FILE MODIFICATION ON READ ************************/
2224 /* Files may be modified on read. The following structure contains a complete
2225 * png_store together with extra members to handle modification and a special
2226 * read callback for libpng. To use this the 'modifications' field must be set
2227 * to a list of png_modification structures that actually perform the
2228 * modification, otherwise a png_modifier is functionally equivalent to a
2229 * png_store. There is a special read function, set_modifier_for_read, which
2230 * replaces set_store_for_read.
2232 typedef enum modifier_state
2234 modifier_start, /* Initial value */
2235 modifier_signature, /* Have a signature */
2236 modifier_IHDR /* Have an IHDR */
2239 typedef struct CIE_color
2241 /* A single CIE tristimulus value, representing the unique response of a
2242 * standard observer to a variety of light spectra. The observer recognizes
2243 * all spectra that produce this response as the same color, therefore this
2244 * is effectively a description of a color.
2249 typedef struct color_encoding
2251 /* A description of an (R,G,B) encoding of color (as defined above); this
2252 * includes the actual colors of the (R,G,B) triples (1,0,0), (0,1,0) and
2253 * (0,0,1) plus an encoding value that is used to encode the linear
2254 * components R, G and B to give the actual values R^gamma, G^gamma and
2255 * B^gamma that are stored.
2257 double gamma; /* Encoding (file) gamma of space */
2258 CIE_color red, green, blue; /* End points */
2261 #ifdef PNG_READ_SUPPORTED
2262 #if defined PNG_READ_TRANSFORMS_SUPPORTED && defined PNG_READ_cHRM_SUPPORTED
2264 chromaticity_x(CIE_color c)
2266 return c.X / (c.X + c.Y + c.Z);
2270 chromaticity_y(CIE_color c)
2272 return c.Y / (c.X + c.Y + c.Z);
2276 white_point(const color_encoding *encoding)
2280 white.X = encoding->red.X + encoding->green.X + encoding->blue.X;
2281 white.Y = encoding->red.Y + encoding->green.Y + encoding->blue.Y;
2282 white.Z = encoding->red.Z + encoding->green.Z + encoding->blue.Z;
2286 #endif /* READ_TRANSFORMS && READ_cHRM */
2288 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2290 normalize_color_encoding(color_encoding *encoding)
2292 const double whiteY = encoding->red.Y + encoding->green.Y +
2297 encoding->red.X /= whiteY;
2298 encoding->red.Y /= whiteY;
2299 encoding->red.Z /= whiteY;
2300 encoding->green.X /= whiteY;
2301 encoding->green.Y /= whiteY;
2302 encoding->green.Z /= whiteY;
2303 encoding->blue.X /= whiteY;
2304 encoding->blue.Y /= whiteY;
2305 encoding->blue.Z /= whiteY;
2310 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
2312 safecat_color_encoding(char *buffer, size_t bufsize, size_t pos,
2313 const color_encoding *e, double encoding_gamma)
2317 if (encoding_gamma != 0)
2318 pos = safecat(buffer, bufsize, pos, "(");
2319 pos = safecat(buffer, bufsize, pos, "R(");
2320 pos = safecatd(buffer, bufsize, pos, e->red.X, 4);
2321 pos = safecat(buffer, bufsize, pos, ",");
2322 pos = safecatd(buffer, bufsize, pos, e->red.Y, 4);
2323 pos = safecat(buffer, bufsize, pos, ",");
2324 pos = safecatd(buffer, bufsize, pos, e->red.Z, 4);
2325 pos = safecat(buffer, bufsize, pos, "),G(");
2326 pos = safecatd(buffer, bufsize, pos, e->green.X, 4);
2327 pos = safecat(buffer, bufsize, pos, ",");
2328 pos = safecatd(buffer, bufsize, pos, e->green.Y, 4);
2329 pos = safecat(buffer, bufsize, pos, ",");
2330 pos = safecatd(buffer, bufsize, pos, e->green.Z, 4);
2331 pos = safecat(buffer, bufsize, pos, "),B(");
2332 pos = safecatd(buffer, bufsize, pos, e->blue.X, 4);
2333 pos = safecat(buffer, bufsize, pos, ",");
2334 pos = safecatd(buffer, bufsize, pos, e->blue.Y, 4);
2335 pos = safecat(buffer, bufsize, pos, ",");
2336 pos = safecatd(buffer, bufsize, pos, e->blue.Z, 4);
2337 pos = safecat(buffer, bufsize, pos, ")");
2338 if (encoding_gamma != 0)
2339 pos = safecat(buffer, bufsize, pos, ")");
2342 if (encoding_gamma != 0)
2344 pos = safecat(buffer, bufsize, pos, "^");
2345 pos = safecatd(buffer, bufsize, pos, encoding_gamma, 5);
2350 #endif /* READ_TRANSFORMS */
2351 #endif /* PNG_READ_SUPPORTED */
2353 typedef struct png_modifier
2355 png_store this; /* I am a png_store */
2356 struct png_modification *modifications; /* Changes to make */
2358 modifier_state state; /* My state */
2360 /* Information from IHDR: */
2361 png_byte bit_depth; /* From IHDR */
2362 png_byte colour_type; /* From IHDR */
2364 /* While handling PLTE, IDAT and IEND these chunks may be pended to allow
2365 * other chunks to be inserted.
2367 png_uint_32 pending_len;
2368 png_uint_32 pending_chunk;
2372 unsigned int ngammas;
2373 unsigned int ngamma_tests; /* Number of gamma tests to run*/
2374 double current_gamma; /* 0 if not set */
2375 const color_encoding *encodings;
2376 unsigned int nencodings;
2377 const color_encoding *current_encoding; /* If an encoding has been set */
2378 unsigned int encoding_counter; /* For iteration */
2379 int encoding_ignored; /* Something overwrote it */
2381 /* Control variables used to iterate through possible encodings, the
2382 * following must be set to 0 and tested by the function that uses the
2383 * png_modifier because the modifier only sets it to 1 (true.)
2385 unsigned int repeat :1; /* Repeat this transform test. */
2386 unsigned int test_uses_encoding :1;
2388 /* Lowest sbit to test (pre-1.7 libpng fails for sbit < 8) */
2391 /* Error control - these are the limits on errors accepted by the gamma tests
2394 double maxout8; /* Maximum output value error */
2395 double maxabs8; /* Absolute sample error 0..1 */
2396 double maxcalc8; /* Absolute sample error 0..1 */
2397 double maxpc8; /* Percentage sample error 0..100% */
2398 double maxout16; /* Maximum output value error */
2399 double maxabs16; /* Absolute sample error 0..1 */
2400 double maxcalc16;/* Absolute sample error 0..1 */
2401 double maxcalcG; /* Absolute sample error 0..1 */
2402 double maxpc16; /* Percentage sample error 0..100% */
2404 /* This is set by transforms that need to allow a higher limit, it is an
2405 * internal check on pngvalid to ensure that the calculated error limits are
2406 * not ridiculous; without this it is too easy to make a mistake in pngvalid
2407 * that allows any value through.
2409 * NOTE: this is not checked in release builds.
2411 double limit; /* limit on error values, normally 4E-3 */
2413 /* Log limits - values above this are logged, but not necessarily
2416 double log8; /* Absolute error in 8 bits to log */
2417 double log16; /* Absolute error in 16 bits to log */
2419 /* Logged 8 and 16 bit errors ('output' values): */
2420 double error_gray_2;
2421 double error_gray_4;
2422 double error_gray_8;
2423 double error_gray_16;
2424 double error_color_8;
2425 double error_color_16;
2426 double error_indexed;
2429 /* Whether to call png_read_update_info, not png_read_start_image, and how
2430 * many times to call it.
2432 int use_update_info;
2434 /* Whether or not to interlace. */
2435 int interlace_type :9; /* int, but must store '1' */
2437 /* Run the standard tests? */
2438 unsigned int test_standard :1;
2440 /* Run the odd-sized image and interlace read/write tests? */
2441 unsigned int test_size :1;
2443 /* Run tests on reading with a combination of transforms, */
2444 unsigned int test_transform :1;
2445 unsigned int test_tRNS :1; /* Includes tRNS images */
2447 /* When to use the use_input_precision option, this controls the gamma
2448 * validation code checks. If set any value that is within the transformed
2449 * range input-.5 to input+.5 will be accepted, otherwise the value must be
2450 * within the normal limits. It should not be necessary to set this; the
2451 * result should always be exact within the permitted error limits.
2453 unsigned int use_input_precision :1;
2454 unsigned int use_input_precision_sbit :1;
2455 unsigned int use_input_precision_16to8 :1;
2457 /* If set assume that the calculation bit depth is set by the input
2458 * precision, not the output precision.
2460 unsigned int calculations_use_input_precision :1;
2462 /* If set assume that the calculations are done in 16 bits even if the sample
2465 unsigned int assume_16_bit_calculations :1;
2467 /* Which gamma tests to run: */
2468 unsigned int test_gamma_threshold :1;
2469 unsigned int test_gamma_transform :1; /* main tests */
2470 unsigned int test_gamma_sbit :1;
2471 unsigned int test_gamma_scale16 :1;
2472 unsigned int test_gamma_background :1;
2473 unsigned int test_gamma_alpha_mode :1;
2474 unsigned int test_gamma_expand16 :1;
2475 unsigned int test_exhaustive :1;
2477 /* Whether or not to run the low-bit-depth grayscale tests. This fails on
2478 * gamma images in some cases because of gross inaccuracies in the grayscale
2479 * gamma handling for low bit depth.
2481 unsigned int test_lbg :1;
2482 unsigned int test_lbg_gamma_threshold :1;
2483 unsigned int test_lbg_gamma_transform :1;
2484 unsigned int test_lbg_gamma_sbit :1;
2485 unsigned int test_lbg_gamma_composition :1;
2487 unsigned int log :1; /* Log max error */
2489 /* Buffer information, the buffer size limits the size of the chunks that can
2490 * be modified - they must fit (including header and CRC) into the buffer!
2492 size_t flush; /* Count of bytes to flush */
2493 size_t buffer_count; /* Bytes in buffer */
2494 size_t buffer_position; /* Position in buffer */
2495 png_byte buffer[1024];
2498 /* This returns true if the test should be stopped now because it has already
2499 * failed and it is running silently.
2501 static int fail(png_modifier *pm)
2503 return !pm->log && !pm->this.verbose && (pm->this.nerrors > 0 ||
2504 (pm->this.treat_warnings_as_errors && pm->this.nwarnings > 0));
2508 modifier_init(png_modifier *pm)
2510 memset(pm, 0, sizeof *pm);
2511 store_init(&pm->this);
2512 pm->modifications = NULL;
2513 pm->state = modifier_start;
2516 pm->ngamma_tests = 0;
2518 pm->current_gamma = 0;
2521 pm->current_encoding = 0;
2522 pm->encoding_counter = 0;
2523 pm->encoding_ignored = 0;
2525 pm->test_uses_encoding = 0;
2526 pm->maxout8 = pm->maxpc8 = pm->maxabs8 = pm->maxcalc8 = 0;
2527 pm->maxout16 = pm->maxpc16 = pm->maxabs16 = pm->maxcalc16 = 0;
2530 pm->log8 = pm->log16 = 0; /* Means 'off' */
2531 pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
2532 pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
2533 pm->error_indexed = 0;
2534 pm->use_update_info = 0;
2535 pm->interlace_type = PNG_INTERLACE_NONE;
2536 pm->test_standard = 0;
2538 pm->test_transform = 0;
2539 # ifdef PNG_WRITE_tRNS_SUPPORTED
2544 pm->use_input_precision = 0;
2545 pm->use_input_precision_sbit = 0;
2546 pm->use_input_precision_16to8 = 0;
2547 pm->calculations_use_input_precision = 0;
2548 pm->assume_16_bit_calculations = 0;
2549 pm->test_gamma_threshold = 0;
2550 pm->test_gamma_transform = 0;
2551 pm->test_gamma_sbit = 0;
2552 pm->test_gamma_scale16 = 0;
2553 pm->test_gamma_background = 0;
2554 pm->test_gamma_alpha_mode = 0;
2555 pm->test_gamma_expand16 = 0;
2557 pm->test_lbg_gamma_threshold = 1;
2558 pm->test_lbg_gamma_transform = 1;
2559 pm->test_lbg_gamma_sbit = 1;
2560 pm->test_lbg_gamma_composition = 1;
2561 pm->test_exhaustive = 0;
2564 /* Rely on the memset for all the other fields - there are no pointers */
2567 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
2569 /* This controls use of checks that explicitly know how libpng digitizes the
2570 * samples in calculations; setting this circumvents simple error limit checking
2571 * in the rgb_to_gray check, replacing it with an exact copy of the libpng 1.5
2574 #define DIGITIZE PNG_LIBPNG_VER < 10700
2576 /* If pm->calculations_use_input_precision is set then operations will happen
2577 * with the precision of the input, not the precision of the output depth.
2579 * If pm->assume_16_bit_calculations is set then even 8 bit calculations use 16
2580 * bit precision. This only affects those of the following limits that pertain
2581 * to a calculation - not a digitization operation - unless the following API is
2584 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2586 static double digitize(double value, int depth, int do_round)
2588 /* 'value' is in the range 0 to 1, the result is the same value rounded to a
2589 * multiple of the digitization factor - 8 or 16 bits depending on both the
2590 * sample depth and the 'assume' setting. Digitization is normally by
2591 * rounding and 'do_round' should be 1, if it is 0 the digitized value will
2594 unsigned int digitization_factor = (1U << depth) - 1;
2596 /* Limiting the range is done as a convenience to the caller - it's easier to
2597 * do it once here than every time at the call site.
2602 else if (value >= 1)
2605 value *= digitization_factor;
2606 if (do_round) value += .5;
2607 return floor(value)/digitization_factor;
2610 #endif /* RGB_TO_GRAY */
2612 #ifdef PNG_READ_GAMMA_SUPPORTED
2613 static double abserr(const png_modifier *pm, int in_depth, int out_depth)
2615 /* Absolute error permitted in linear values - affected by the bit depth of
2618 if (pm->assume_16_bit_calculations ||
2619 (pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2620 return pm->maxabs16;
2625 static double calcerr(const png_modifier *pm, int in_depth, int out_depth)
2627 /* Error in the linear composition arithmetic - only relevant when
2628 * composition actually happens (0 < alpha < 1).
2630 if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2631 return pm->maxcalc16;
2632 else if (pm->assume_16_bit_calculations)
2633 return pm->maxcalcG;
2635 return pm->maxcalc8;
2638 static double pcerr(const png_modifier *pm, int in_depth, int out_depth)
2640 /* Percentage error permitted in the linear values. Note that the specified
2641 * value is a percentage but this routine returns a simple number.
2643 if (pm->assume_16_bit_calculations ||
2644 (pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2645 return pm->maxpc16 * .01;
2647 return pm->maxpc8 * .01;
2650 /* Output error - the error in the encoded value. This is determined by the
2651 * digitization of the output so can be +/-0.5 in the actual output value. In
2652 * the expand_16 case with the current code in libpng the expand happens after
2653 * all the calculations are done in 8 bit arithmetic, so even though the output
2654 * depth is 16 the output error is determined by the 8 bit calculation.
2656 * This limit is not determined by the bit depth of internal calculations.
2658 * The specified parameter does *not* include the base .5 digitization error but
2661 static double outerr(const png_modifier *pm, int in_depth, int out_depth)
2663 /* There is a serious error in the 2 and 4 bit grayscale transform because
2664 * the gamma table value (8 bits) is simply shifted, not rounded, so the
2665 * error in 4 bit grayscale gamma is up to the value below. This is a hack
2666 * to allow pngvalid to succeed:
2668 * TODO: fix this in libpng
2676 if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2677 return pm->maxout16;
2679 /* This is the case where the value was calculated at 8-bit precision then
2680 * scaled to 16 bits.
2682 else if (out_depth == 16)
2683 return pm->maxout8 * 257;
2689 /* This does the same thing as the above however it returns the value to log,
2690 * rather than raising a warning. This is useful for debugging to track down
2691 * exactly what set of parameters cause high error values.
2693 static double outlog(const png_modifier *pm, int in_depth, int out_depth)
2695 /* The command line parameters are either 8 bit (0..255) or 16 bit (0..65535)
2696 * and so must be adjusted for low bit depth grayscale:
2700 if (pm->log8 == 0) /* switched off */
2704 return pm->log8 / 255 * ((1<<out_depth)-1);
2709 if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2717 /* This is the case where the value was calculated at 8-bit precision then
2718 * scaled to 16 bits.
2723 return pm->log8 * 257;
2726 /* This complements the above by providing the appropriate quantization for the
2727 * final value. Normally this would just be quantization to an integral value,
2728 * but in the 8 bit calculation case it's actually quantization to a multiple of
2731 static int output_quantization_factor(const png_modifier *pm, int in_depth,
2734 if (out_depth == 16 && in_depth != 16 &&
2735 pm->calculations_use_input_precision)
2740 #endif /* PNG_READ_GAMMA_SUPPORTED */
2742 /* One modification structure must be provided for each chunk to be modified (in
2743 * fact more than one can be provided if multiple separate changes are desired
2744 * for a single chunk.) Modifications include adding a new chunk when a
2745 * suitable chunk does not exist.
2747 * The caller of modify_fn will reset the CRC of the chunk and record 'modified'
2748 * or 'added' as appropriate if the modify_fn returns 1 (true). If the
2749 * modify_fn is NULL the chunk is simply removed.
2751 typedef struct png_modification
2753 struct png_modification *next;
2756 /* If the following is NULL all matching chunks will be removed: */
2757 int (*modify_fn)(struct png_modifier *pm,
2758 struct png_modification *me, int add);
2760 /* If the following is set to PLTE, IDAT or IEND and the chunk has not been
2761 * found and modified (and there is a modify_fn) the modify_fn will be called
2762 * to add the chunk before the relevant chunk.
2765 unsigned int modified :1; /* Chunk was modified */
2766 unsigned int added :1; /* Chunk was added */
2767 unsigned int removed :1; /* Chunk was removed */
2771 modification_reset(png_modification *pmm)
2778 modification_reset(pmm->next);
2783 modification_init(png_modification *pmm)
2785 memset(pmm, 0, sizeof *pmm);
2788 pmm->modify_fn = NULL;
2790 modification_reset(pmm);
2793 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2795 modifier_current_encoding(const png_modifier *pm, color_encoding *ce)
2797 if (pm->current_encoding != 0)
2798 *ce = *pm->current_encoding;
2801 memset(ce, 0, sizeof *ce);
2803 ce->gamma = pm->current_gamma;
2807 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
2809 safecat_current_encoding(char *buffer, size_t bufsize, size_t pos,
2810 const png_modifier *pm)
2812 pos = safecat_color_encoding(buffer, bufsize, pos, pm->current_encoding,
2815 if (pm->encoding_ignored)
2816 pos = safecat(buffer, bufsize, pos, "[overridden]");
2822 /* Iterate through the usefully testable color encodings. An encoding is one
2825 * 1) Nothing (no color space, no gamma).
2826 * 2) Just a gamma value from the gamma array (including 1.0)
2827 * 3) A color space from the encodings array with the corresponding gamma.
2828 * 4) The same, but with gamma 1.0 (only really useful with 16 bit calculations)
2830 * The iterator selects these in turn, the randomizer selects one at random,
2831 * which is used depends on the setting of the 'test_exhaustive' flag. Notice
2832 * that this function changes the colour space encoding so it must only be
2833 * called on completion of the previous test. This is what 'modifier_reset'
2836 * After the function has been called the 'repeat' flag will still be set; the
2837 * caller of modifier_reset must reset it at the start of each run of the test!
2840 modifier_total_encodings(const png_modifier *pm)
2842 return 1 + /* (1) nothing */
2843 pm->ngammas + /* (2) gamma values to test */
2844 pm->nencodings + /* (3) total number of encodings */
2845 /* The following test only works after the first time through the
2846 * png_modifier code because 'bit_depth' is set when the IHDR is read.
2847 * modifier_reset, below, preserves the setting until after it has called
2848 * the iterate function (also below.)
2850 * For this reason do not rely on this function outside a call to
2853 ((pm->bit_depth == 16 || pm->assume_16_bit_calculations) ?
2854 pm->nencodings : 0); /* (4) encodings with gamma == 1.0 */
2858 modifier_encoding_iterate(png_modifier *pm)
2860 if (!pm->repeat && /* Else something needs the current encoding again. */
2861 pm->test_uses_encoding) /* Some transform is encoding dependent */
2863 if (pm->test_exhaustive)
2865 if (++pm->encoding_counter >= modifier_total_encodings(pm))
2866 pm->encoding_counter = 0; /* This will stop the repeat */
2871 /* Not exhaustive - choose an encoding at random; generate a number in
2872 * the range 1..(max-1), so the result is always non-zero:
2874 if (pm->encoding_counter == 0)
2875 pm->encoding_counter = random_mod(modifier_total_encodings(pm)-1)+1;
2877 pm->encoding_counter = 0;
2880 if (pm->encoding_counter > 0)
2884 else if (!pm->repeat)
2885 pm->encoding_counter = 0;
2889 modifier_reset(png_modifier *pm)
2891 store_read_reset(&pm->this);
2893 pm->pending_len = pm->pending_chunk = 0;
2894 pm->flush = pm->buffer_count = pm->buffer_position = 0;
2895 pm->modifications = NULL;
2896 pm->state = modifier_start;
2897 modifier_encoding_iterate(pm);
2898 /* The following must be set in the next run. In particular
2899 * test_uses_encodings must be set in the _ini function of each transform
2900 * that looks at the encodings. (Not the 'add' function!)
2902 pm->test_uses_encoding = 0;
2903 pm->current_gamma = 0;
2904 pm->current_encoding = 0;
2905 pm->encoding_ignored = 0;
2906 /* These only become value after IHDR is read: */
2907 pm->bit_depth = pm->colour_type = 0;
2910 /* The following must be called before anything else to get the encoding set up
2911 * on the modifier. In particular it must be called before the transform init
2912 * functions are called.
2915 modifier_set_encoding(png_modifier *pm)
2917 /* Set the encoding to the one specified by the current encoding counter,
2918 * first clear out all the settings - this corresponds to an encoding_counter
2921 pm->current_gamma = 0;
2922 pm->current_encoding = 0;
2923 pm->encoding_ignored = 0; /* not ignored yet - happens in _ini functions. */
2925 /* Now, if required, set the gamma and encoding fields. */
2926 if (pm->encoding_counter > 0)
2928 /* The gammas[] array is an array of screen gammas, not encoding gammas,
2929 * so we need the inverse:
2931 if (pm->encoding_counter <= pm->ngammas)
2932 pm->current_gamma = 1/pm->gammas[pm->encoding_counter-1];
2936 unsigned int i = pm->encoding_counter - pm->ngammas;
2938 if (i >= pm->nencodings)
2940 i %= pm->nencodings;
2941 pm->current_gamma = 1; /* Linear, only in the 16 bit case */
2945 pm->current_gamma = pm->encodings[i].gamma;
2947 pm->current_encoding = pm->encodings + i;
2952 /* Enquiry functions to find out what is set. Notice that there is an implicit
2953 * assumption below that the first encoding in the list is the one for sRGB.
2956 modifier_color_encoding_is_sRGB(const png_modifier *pm)
2958 return pm->current_encoding != 0 && pm->current_encoding == pm->encodings &&
2959 pm->current_encoding->gamma == pm->current_gamma;
2963 modifier_color_encoding_is_set(const png_modifier *pm)
2965 return pm->current_gamma != 0;
2968 /* The guts of modification are performed during a read. */
2970 modifier_crc(png_bytep buffer)
2972 /* Recalculate the chunk CRC - a complete chunk must be in
2973 * the buffer, at the start.
2975 uInt datalen = png_get_uint_32(buffer);
2976 uLong crc = crc32(0, buffer+4, datalen+4);
2977 /* The cast to png_uint_32 is safe because a crc32 is always a 32 bit value.
2979 png_save_uint_32(buffer+datalen+8, (png_uint_32)crc);
2983 modifier_setbuffer(png_modifier *pm)
2985 modifier_crc(pm->buffer);
2986 pm->buffer_count = png_get_uint_32(pm->buffer)+12;
2987 pm->buffer_position = 0;
2990 /* Separate the callback into the actual implementation (which is passed the
2991 * png_modifier explicitly) and the callback, which gets the modifier from the
2995 modifier_read_imp(png_modifier *pm, png_bytep pb, size_t st)
3000 png_uint_32 len, chunk;
3001 png_modification *mod;
3003 if (pm->buffer_position >= pm->buffer_count) switch (pm->state)
3005 static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
3006 case modifier_start:
3007 store_read_chunk(&pm->this, pm->buffer, 8, 8); /* signature. */
3008 pm->buffer_count = 8;
3009 pm->buffer_position = 0;
3011 if (memcmp(pm->buffer, sign, 8) != 0)
3012 png_error(pm->this.pread, "invalid PNG file signature");
3013 pm->state = modifier_signature;
3016 case modifier_signature:
3017 store_read_chunk(&pm->this, pm->buffer, 13+12, 13+12); /* IHDR */
3018 pm->buffer_count = 13+12;
3019 pm->buffer_position = 0;
3021 if (png_get_uint_32(pm->buffer) != 13 ||
3022 png_get_uint_32(pm->buffer+4) != CHUNK_IHDR)
3023 png_error(pm->this.pread, "invalid IHDR");
3025 /* Check the list of modifiers for modifications to the IHDR. */
3026 mod = pm->modifications;
3029 if (mod->chunk == CHUNK_IHDR && mod->modify_fn &&
3030 (*mod->modify_fn)(pm, mod, 0))
3033 modifier_setbuffer(pm);
3036 /* Ignore removal or add if IHDR! */
3040 /* Cache information from the IHDR (the modified one.) */
3041 pm->bit_depth = pm->buffer[8+8];
3042 pm->colour_type = pm->buffer[8+8+1];
3044 pm->state = modifier_IHDR;
3050 /* Read a new chunk and process it until we see PLTE, IDAT or
3051 * IEND. 'flush' indicates that there is still some data to
3052 * output from the preceding chunk.
3054 if ((cb = pm->flush) > 0)
3056 if (cb > st) cb = st;
3058 store_read_chunk(&pm->this, pb, cb, cb);
3061 if (st == 0) return;
3064 /* No more bytes to flush, read a header, or handle a pending
3067 if (pm->pending_chunk != 0)
3069 png_save_uint_32(pm->buffer, pm->pending_len);
3070 png_save_uint_32(pm->buffer+4, pm->pending_chunk);
3071 pm->pending_len = 0;
3072 pm->pending_chunk = 0;
3075 store_read_chunk(&pm->this, pm->buffer, 8, 8);
3077 pm->buffer_count = 8;
3078 pm->buffer_position = 0;
3080 /* Check for something to modify or a terminator chunk. */
3081 len = png_get_uint_32(pm->buffer);
3082 chunk = png_get_uint_32(pm->buffer+4);
3084 /* Terminators first, they may have to be delayed for added
3087 if (chunk == CHUNK_PLTE || chunk == CHUNK_IDAT ||
3088 chunk == CHUNK_IEND)
3090 mod = pm->modifications;
3094 if ((mod->add == chunk ||
3095 (mod->add == CHUNK_PLTE && chunk == CHUNK_IDAT)) &&
3096 mod->modify_fn != NULL && !mod->modified && !mod->added)
3098 /* Regardless of what the modify function does do not run
3103 if ((*mod->modify_fn)(pm, mod, 1 /*add*/))
3105 /* Reset the CRC on a new chunk */
3106 if (pm->buffer_count > 0)
3107 modifier_setbuffer(pm);
3111 pm->buffer_position = 0;
3115 /* The buffer has been filled with something (we assume)
3116 * so output this. Pend the current chunk.
3118 pm->pending_len = len;
3119 pm->pending_chunk = chunk;
3120 break; /* out of while */
3127 /* Don't do any further processing if the buffer was modified -
3128 * otherwise the code will end up modifying a chunk that was
3132 break; /* out of switch */
3135 /* If we get to here then this chunk may need to be modified. To
3136 * do this it must be less than 1024 bytes in total size, otherwise
3137 * it just gets flushed.
3139 if (len+12 <= sizeof pm->buffer)
3141 size_t s = len+12-pm->buffer_count;
3142 store_read_chunk(&pm->this, pm->buffer+pm->buffer_count, s, s);
3143 pm->buffer_count = len+12;
3145 /* Check for a modification, else leave it be. */
3146 mod = pm->modifications;
3149 if (mod->chunk == chunk)
3151 if (mod->modify_fn == NULL)
3153 /* Remove this chunk */
3154 pm->buffer_count = pm->buffer_position = 0;
3156 break; /* Terminate the while loop */
3159 else if ((*mod->modify_fn)(pm, mod, 0))
3162 /* The chunk may have been removed: */
3163 if (pm->buffer_count == 0)
3165 pm->buffer_position = 0;
3168 modifier_setbuffer(pm);
3177 pm->flush = len+12 - pm->buffer_count; /* data + crc */
3179 /* Take the data from the buffer (if there is any). */
3183 /* Here to read from the modifier buffer (not directly from
3184 * the store, as in the flush case above.)
3186 cb = pm->buffer_count - pm->buffer_position;
3191 memcpy(pb, pm->buffer + pm->buffer_position, cb);
3194 pm->buffer_position += cb;
3199 static void PNGCBAPI
3200 modifier_read(png_structp ppIn, png_bytep pb, size_t st)
3202 png_const_structp pp = ppIn;
3203 png_modifier *pm = voidcast(png_modifier*, png_get_io_ptr(pp));
3205 if (pm == NULL || pm->this.pread != pp)
3206 png_error(pp, "bad modifier_read call");
3208 modifier_read_imp(pm, pb, st);
3211 /* Like store_progressive_read but the data is getting changed as we go so we
3212 * need a local buffer.
3215 modifier_progressive_read(png_modifier *pm, png_structp pp, png_infop pi)
3217 if (pm->this.pread != pp || pm->this.current == NULL ||
3218 pm->this.next == NULL)
3219 png_error(pp, "store state damaged (progressive)");
3221 /* This is another Horowitz and Hill random noise generator. In this case
3222 * the aim is to stress the progressive reader with truly horrible variable
3223 * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
3224 * is generated. We could probably just count from 1 to 32767 and get as
3229 static png_uint_32 noise = 1;
3231 png_byte buffer[512];
3233 /* Generate 15 more bits of stuff: */
3234 noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
3237 /* Check that this number of bytes are available (in the current buffer.)
3238 * (This doesn't quite work - the modifier might delete a chunk; unlikely
3239 * but possible, it doesn't happen at present because the modifier only
3240 * adds chunks to standard images.)
3242 cbAvail = store_read_buffer_avail(&pm->this);
3243 if (pm->buffer_count > pm->buffer_position)
3244 cbAvail += pm->buffer_count - pm->buffer_position;
3248 /* Check for EOF: */
3255 modifier_read_imp(pm, buffer, cb);
3256 png_process_data(pp, pi, buffer, cb);
3259 /* Check the invariants at the end (if this fails it's a problem in this
3262 if (pm->buffer_count > pm->buffer_position ||
3263 pm->this.next != &pm->this.current->data ||
3264 pm->this.readpos < pm->this.current->datacount)
3265 png_error(pp, "progressive read implementation error");
3268 /* Set up a modifier. */
3270 set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id,
3273 /* Do this first so that the modifier fields are cleared even if an error
3274 * happens allocating the png_struct. No allocation is done here so no
3275 * cleanup is required.
3277 pm->state = modifier_start;
3279 pm->colour_type = 255;
3281 pm->pending_len = 0;
3282 pm->pending_chunk = 0;
3284 pm->buffer_count = 0;
3285 pm->buffer_position = 0;
3287 return set_store_for_read(&pm->this, ppi, id, name);
3291 /******************************** MODIFICATIONS *******************************/
3292 /* Standard modifications to add chunks. These do not require the _SUPPORTED
3293 * macros because the chunks can be there regardless of whether this specific
3294 * libpng supports them.
3296 typedef struct gama_modification
3298 png_modification this;
3299 png_fixed_point gamma;
3300 } gama_modification;
3303 gama_modify(png_modifier *pm, png_modification *me, int add)
3306 /* This simply dumps the given gamma value into the buffer. */
3307 png_save_uint_32(pm->buffer, 4);
3308 png_save_uint_32(pm->buffer+4, CHUNK_gAMA);
3309 png_save_uint_32(pm->buffer+8, ((gama_modification*)me)->gamma);
3314 gama_modification_init(gama_modification *me, png_modifier *pm, double gammad)
3318 modification_init(&me->this);
3319 me->this.chunk = CHUNK_gAMA;
3320 me->this.modify_fn = gama_modify;
3321 me->this.add = CHUNK_PLTE;
3323 me->gamma = (png_fixed_point)g;
3324 me->this.next = pm->modifications;
3325 pm->modifications = &me->this;
3328 typedef struct chrm_modification
3330 png_modification this;
3331 const color_encoding *encoding;
3332 png_fixed_point wx, wy, rx, ry, gx, gy, bx, by;
3333 } chrm_modification;
3336 chrm_modify(png_modifier *pm, png_modification *me, int add)
3339 /* As with gAMA this just adds the required cHRM chunk to the buffer. */
3340 png_save_uint_32(pm->buffer , 32);
3341 png_save_uint_32(pm->buffer+ 4, CHUNK_cHRM);
3342 png_save_uint_32(pm->buffer+ 8, ((chrm_modification*)me)->wx);
3343 png_save_uint_32(pm->buffer+12, ((chrm_modification*)me)->wy);
3344 png_save_uint_32(pm->buffer+16, ((chrm_modification*)me)->rx);
3345 png_save_uint_32(pm->buffer+20, ((chrm_modification*)me)->ry);
3346 png_save_uint_32(pm->buffer+24, ((chrm_modification*)me)->gx);
3347 png_save_uint_32(pm->buffer+28, ((chrm_modification*)me)->gy);
3348 png_save_uint_32(pm->buffer+32, ((chrm_modification*)me)->bx);
3349 png_save_uint_32(pm->buffer+36, ((chrm_modification*)me)->by);
3354 chrm_modification_init(chrm_modification *me, png_modifier *pm,
3355 const color_encoding *encoding)
3357 CIE_color white = white_point(encoding);
3359 /* Original end points: */
3360 me->encoding = encoding;
3362 /* Chromaticities (in fixed point): */
3363 me->wx = fix(chromaticity_x(white));
3364 me->wy = fix(chromaticity_y(white));
3366 me->rx = fix(chromaticity_x(encoding->red));
3367 me->ry = fix(chromaticity_y(encoding->red));
3368 me->gx = fix(chromaticity_x(encoding->green));
3369 me->gy = fix(chromaticity_y(encoding->green));
3370 me->bx = fix(chromaticity_x(encoding->blue));
3371 me->by = fix(chromaticity_y(encoding->blue));
3373 modification_init(&me->this);
3374 me->this.chunk = CHUNK_cHRM;
3375 me->this.modify_fn = chrm_modify;
3376 me->this.add = CHUNK_PLTE;
3377 me->this.next = pm->modifications;
3378 pm->modifications = &me->this;
3381 typedef struct srgb_modification
3383 png_modification this;
3385 } srgb_modification;
3388 srgb_modify(png_modifier *pm, png_modification *me, int add)
3391 /* As above, ignore add and just make a new chunk */
3392 png_save_uint_32(pm->buffer, 1);
3393 png_save_uint_32(pm->buffer+4, CHUNK_sRGB);
3394 pm->buffer[8] = ((srgb_modification*)me)->intent;
3399 srgb_modification_init(srgb_modification *me, png_modifier *pm, png_byte intent)
3401 modification_init(&me->this);
3402 me->this.chunk = CHUNK_sBIT;
3404 if (intent <= 3) /* if valid, else *delete* sRGB chunks */
3406 me->this.modify_fn = srgb_modify;
3407 me->this.add = CHUNK_PLTE;
3408 me->intent = intent;
3413 me->this.modify_fn = 0;
3418 me->this.next = pm->modifications;
3419 pm->modifications = &me->this;
3422 #ifdef PNG_READ_GAMMA_SUPPORTED
3423 typedef struct sbit_modification
3425 png_modification this;
3427 } sbit_modification;
3430 sbit_modify(png_modifier *pm, png_modification *me, int add)
3432 png_byte sbit = ((sbit_modification*)me)->sbit;
3433 if (pm->bit_depth > sbit)
3436 switch (pm->colour_type)
3456 png_error(pm->this.pread,
3457 "unexpected colour type in sBIT modification");
3460 png_save_uint_32(pm->buffer, cb);
3461 png_save_uint_32(pm->buffer+4, CHUNK_sBIT);
3464 (pm->buffer+8)[--cb] = sbit;
3470 /* Remove the sBIT chunk */
3471 pm->buffer_count = pm->buffer_position = 0;
3475 return 0; /* do nothing */
3479 sbit_modification_init(sbit_modification *me, png_modifier *pm, png_byte sbit)
3481 modification_init(&me->this);
3482 me->this.chunk = CHUNK_sBIT;
3483 me->this.modify_fn = sbit_modify;
3484 me->this.add = CHUNK_PLTE;
3486 me->this.next = pm->modifications;
3487 pm->modifications = &me->this;
3489 #endif /* PNG_READ_GAMMA_SUPPORTED */
3490 #endif /* PNG_READ_TRANSFORMS_SUPPORTED */
3492 /***************************** STANDARD PNG FILES *****************************/
3493 /* Standard files - write and save standard files. */
3494 /* There are two basic forms of standard images. Those which attempt to have
3495 * all the possible pixel values (not possible for 16bpp images, but a range of
3496 * values are produced) and those which have a range of image sizes. The former
3497 * are used for testing transforms, in particular gamma correction and bit
3498 * reduction and increase. The latter are reserved for testing the behavior of
3499 * libpng with respect to 'odd' image sizes - particularly small images where
3500 * rows become 1 byte and interlace passes disappear.
3502 * The first, most useful, set are the 'transform' images, the second set of
3503 * small images are the 'size' images.
3505 * The transform files are constructed with rows which fit into a 1024 byte row
3506 * buffer. This makes allocation easier below. Further regardless of the file
3507 * format every row has 128 pixels (giving 1024 bytes for 64bpp formats).
3509 * Files are stored with no gAMA or sBIT chunks, with a PLTE only when needed
3510 * and with an ID derived from the colour type, bit depth and interlace type
3511 * as above (FILEID). The width (128) and height (variable) are not stored in
3512 * the FILEID - instead the fields are set to 0, indicating a transform file.
3514 * The size files ar constructed with rows a maximum of 128 bytes wide, allowing
3515 * a maximum width of 16 pixels (for the 64bpp case.) They also have a maximum
3516 * height of 16 rows. The width and height are stored in the FILEID and, being
3517 * non-zero, indicate a size file.
3519 * Because the PNG filter code is typically the largest CPU consumer within
3520 * libpng itself there is a tendency to attempt to optimize it. This results in
3521 * special case code which needs to be validated. To cause this to happen the
3522 * 'size' images are made to use each possible filter, in so far as this is
3523 * possible for smaller images.
3525 * For palette image (colour type 3) multiple transform images are stored with
3526 * the same bit depth to allow testing of more colour combinations -
3527 * particularly important for testing the gamma code because libpng uses a
3528 * different code path for palette images. For size images a single palette is
3532 /* Make a 'standard' palette. Because there are only 256 entries in a palette
3533 * (maximum) this actually makes a random palette in the hope that enough tests
3534 * will catch enough errors. (Note that the same palette isn't produced every
3535 * time for the same test - it depends on what previous tests have been run -
3536 * but a given set of arguments to pngvalid will always produce the same palette
3537 * at the same test! This is why pseudo-random number generators are useful for
3540 * The store must be open for write when this is called, otherwise an internal
3541 * error will occur. This routine contains its own magic number seed, so the
3542 * palettes generated don't change if there are intervening errors (changing the
3543 * calls to the store_mark seed.)
3545 static store_palette_entry *
3546 make_standard_palette(png_store* ps, int npalette, int do_tRNS)
3548 static png_uint_32 palette_seed[2] = { 0x87654321, 9 };
3551 png_byte values[256][4];
3553 /* Always put in black and white plus the six primary and secondary colors.
3557 values[i][1] = (png_byte)((i&1) ? 255U : 0U);
3558 values[i][2] = (png_byte)((i&2) ? 255U : 0U);
3559 values[i][3] = (png_byte)((i&4) ? 255U : 0U);
3562 /* Then add 62 grays (one quarter of the remaining 256 slots). */
3565 png_byte random_bytes[4];
3568 need[0] = 0; /*got black*/
3569 memset(need+1, 1, (sizeof need)-2); /*need these*/
3570 need[255] = 0; /*but not white*/
3578 make_four_random_bytes(palette_seed, random_bytes);
3582 b = random_bytes[--j];
3592 /* Finally add 192 colors at random - don't worry about matches to things we
3593 * already have, chance is less than 1/65536. Don't worry about grays,
3594 * chance is the same, so we get a duplicate or extra gray less than 1 time
3598 make_four_random_bytes(palette_seed, values[i]);
3600 /* Fill in the alpha values in the first byte. Just use all possible values
3601 * (0..255) in an apparently random order:
3604 store_palette_entry *palette;
3605 png_byte selector[4];
3607 make_four_random_bytes(palette_seed, selector);
3610 for (i=0; i<256; ++i)
3611 values[i][0] = (png_byte)(i ^ selector[0]);
3614 for (i=0; i<256; ++i)
3615 values[i][0] = 255; /* no transparency/tRNS chunk */
3617 /* 'values' contains 256 ARGB values, but we only need 'npalette'.
3618 * 'npalette' will always be a power of 2: 2, 4, 16 or 256. In the low
3619 * bit depth cases select colors at random, else it is difficult to have
3620 * a set of low bit depth palette test with any chance of a reasonable
3621 * range of colors. Do this by randomly permuting values into the low
3622 * 'npalette' entries using an XOR mask generated here. This also
3623 * permutes the npalette == 256 case in a potentially useful way (there is
3624 * no relationship between palette index and the color value therein!)
3626 palette = store_write_palette(ps, npalette);
3628 for (i=0; i<npalette; ++i)
3630 palette[i].alpha = values[i ^ selector[1]][0];
3631 palette[i].red = values[i ^ selector[1]][1];
3632 palette[i].green = values[i ^ selector[1]][2];
3633 palette[i].blue = values[i ^ selector[1]][3];
3640 /* Initialize a standard palette on a write stream. The 'do_tRNS' argument
3641 * indicates whether or not to also set the tRNS chunk.
3643 /* TODO: the png_structp here can probably be 'const' in the future */
3645 init_standard_palette(png_store *ps, png_structp pp, png_infop pi, int npalette,
3648 store_palette_entry *ppal = make_standard_palette(ps, npalette, do_tRNS);
3652 png_color palette[256];
3654 /* Set all entries to detect overread errors. */
3655 for (i=0; i<npalette; ++i)
3657 palette[i].red = ppal[i].red;
3658 palette[i].green = ppal[i].green;
3659 palette[i].blue = ppal[i].blue;
3662 /* Just in case fill in the rest with detectable values: */
3664 palette[i].red = palette[i].green = palette[i].blue = 42;
3666 png_set_PLTE(pp, pi, palette, npalette);
3674 /* Set all the entries, but skip trailing opaque entries */
3675 for (i=j=0; i<npalette; ++i)
3676 if ((tRNS[i] = ppal[i].alpha) < 255)
3679 /* Fill in the remainder with a detectable value: */
3683 #ifdef PNG_WRITE_tRNS_SUPPORTED
3685 png_set_tRNS(pp, pi, tRNS, j, 0/*color*/);
3690 #ifdef PNG_WRITE_tRNS_SUPPORTED
3692 set_random_tRNS(png_structp pp, png_infop pi, png_byte colour_type,
3695 /* To make this useful the tRNS color needs to match at least one pixel.
3696 * Random values are fine for gray, including the 16-bit case where we know
3697 * that the test image contains all the gray values. For RGB we need more
3698 * method as only 65536 different RGB values are generated.
3701 png_uint_16 mask = (png_uint_16)((1U << bit_depth)-1);
3703 R8(tRNS); /* makes unset fields random */
3705 if (colour_type & 2/*RGB*/)
3709 tRNS.red = random_u16();
3710 tRNS.green = random_u16();
3711 tRNS.blue = tRNS.red ^ tRNS.green;
3717 else /* bit_depth == 16 */
3719 tRNS.red = random_u16();
3720 tRNS.green = (png_uint_16)(tRNS.red * 257);
3721 tRNS.blue = (png_uint_16)(tRNS.green * 17);
3727 tRNS.gray = random_u16();
3731 png_set_tRNS(pp, pi, NULL, 0, &tRNS);
3735 /* The number of passes is related to the interlace type. There was no libpng
3736 * API to determine this prior to 1.5, so we need an inquiry function:
3739 npasses_from_interlace_type(png_const_structp pp, int interlace_type)
3741 switch (interlace_type)
3744 png_error(pp, "invalid interlace type");
3746 case PNG_INTERLACE_NONE:
3749 case PNG_INTERLACE_ADAM7:
3750 return PNG_INTERLACE_ADAM7_PASSES;
3755 bit_size(png_const_structp pp, png_byte colour_type, png_byte bit_depth)
3757 switch (colour_type)
3759 default: png_error(pp, "invalid color type");
3761 case 0: return bit_depth;
3763 case 2: return 3*bit_depth;
3765 case 3: return bit_depth;
3767 case 4: return 2*bit_depth;
3769 case 6: return 4*bit_depth;
3773 #define TRANSFORM_WIDTH 128U
3774 #define TRANSFORM_ROWMAX (TRANSFORM_WIDTH*8U)
3775 #define SIZE_ROWMAX (16*8U) /* 16 pixels, max 8 bytes each - 128 bytes */
3776 #define STANDARD_ROWMAX TRANSFORM_ROWMAX /* The larger of the two */
3777 #define SIZE_HEIGHTMAX 16 /* Maximum range of size images */
3780 transform_rowsize(png_const_structp pp, png_byte colour_type,
3783 return (TRANSFORM_WIDTH * bit_size(pp, colour_type, bit_depth)) / 8;
3786 /* transform_width(pp, colour_type, bit_depth) current returns the same number
3787 * every time, so just use a macro:
3789 #define transform_width(pp, colour_type, bit_depth) TRANSFORM_WIDTH
3792 transform_height(png_const_structp pp, png_byte colour_type, png_byte bit_depth)
3794 switch (bit_size(pp, colour_type, bit_depth))
3799 return 1; /* Total of 128 pixels */
3802 return 2; /* Total of 256 pixels/bytes */
3805 return 512; /* Total of 65536 pixels */
3809 return 512; /* 65536 pixels */
3813 return 2048;/* 4 x 65536 pixels. */
3814 # define TRANSFORM_HEIGHTMAX 2048
3817 return 0; /* Error, will be caught later */
3821 #ifdef PNG_READ_SUPPORTED
3822 /* The following can only be defined here, now we have the definitions
3823 * of the transform image sizes.
3826 standard_width(png_const_structp pp, png_uint_32 id)
3828 png_uint_32 width = WIDTH_FROM_ID(id);
3832 width = transform_width(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
3838 standard_height(png_const_structp pp, png_uint_32 id)
3840 png_uint_32 height = HEIGHT_FROM_ID(id);
3843 height = transform_height(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
3849 standard_rowsize(png_const_structp pp, png_uint_32 id)
3851 png_uint_32 width = standard_width(pp, id);
3853 /* This won't overflow: */
3854 width *= bit_size(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
3855 return (width + 7) / 8;
3857 #endif /* PNG_READ_SUPPORTED */
3860 transform_row(png_const_structp pp, png_byte buffer[TRANSFORM_ROWMAX],
3861 png_byte colour_type, png_byte bit_depth, png_uint_32 y)
3863 png_uint_32 v = y << 7;
3866 switch (bit_size(pp, colour_type, bit_depth))
3869 while (i<128/8) buffer[i] = (png_byte)(v & 0xff), v += 17, ++i;
3873 while (i<128/4) buffer[i] = (png_byte)(v & 0xff), v += 33, ++i;
3877 while (i<128/2) buffer[i] = (png_byte)(v & 0xff), v += 65, ++i;
3881 /* 256 bytes total, 128 bytes in each row set as follows: */
3882 while (i<128) buffer[i] = (png_byte)(v & 0xff), ++v, ++i;
3886 /* Generate all 65536 pixel values in order, which includes the 8 bit
3887 * GA case as well as the 16 bit G case.
3891 buffer[2*i] = (png_byte)((v>>8) & 0xff);
3892 buffer[2*i+1] = (png_byte)(v & 0xff);
3900 /* 65535 pixels, but rotate the values. */
3903 /* Three bytes per pixel, r, g, b, make b by r^g */
3904 buffer[3*i+0] = (png_byte)((v >> 8) & 0xff);
3905 buffer[3*i+1] = (png_byte)(v & 0xff);
3906 buffer[3*i+2] = (png_byte)(((v >> 8) ^ v) & 0xff);
3914 /* 65535 pixels, r, g, b, a; just replicate */
3917 buffer[4*i+0] = (png_byte)((v >> 8) & 0xff);
3918 buffer[4*i+1] = (png_byte)(v & 0xff);
3919 buffer[4*i+2] = (png_byte)((v >> 8) & 0xff);
3920 buffer[4*i+3] = (png_byte)(v & 0xff);
3928 /* y is maximum 2047, giving 4x65536 pixels, make 'r' increase by 1 at
3929 * each pixel, g increase by 257 (0x101) and 'b' by 0x1111:
3933 png_uint_32 t = v++;
3934 buffer[6*i+0] = (png_byte)((t >> 8) & 0xff);
3935 buffer[6*i+1] = (png_byte)(t & 0xff);
3937 buffer[6*i+2] = (png_byte)((t >> 8) & 0xff);
3938 buffer[6*i+3] = (png_byte)(t & 0xff);
3940 buffer[6*i+4] = (png_byte)((t >> 8) & 0xff);
3941 buffer[6*i+5] = (png_byte)(t & 0xff);
3948 /* As above in the 32 bit case. */
3951 png_uint_32 t = v++;
3952 buffer[8*i+0] = (png_byte)((t >> 8) & 0xff);
3953 buffer[8*i+1] = (png_byte)(t & 0xff);
3954 buffer[8*i+4] = (png_byte)((t >> 8) & 0xff);
3955 buffer[8*i+5] = (png_byte)(t & 0xff);
3957 buffer[8*i+2] = (png_byte)((t >> 8) & 0xff);
3958 buffer[8*i+3] = (png_byte)(t & 0xff);
3959 buffer[8*i+6] = (png_byte)((t >> 8) & 0xff);
3960 buffer[8*i+7] = (png_byte)(t & 0xff);
3969 png_error(pp, "internal error");
3972 /* This is just to do the right cast - could be changed to a function to check
3973 * 'bd' but there isn't much point.
3975 #define DEPTH(bd) ((png_byte)(1U << (bd)))
3977 /* This is just a helper for compiling on minimal systems with no write
3978 * interlacing support. If there is no write interlacing we can't generate test
3979 * cases with interlace:
3981 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
3982 # define INTERLACE_LAST PNG_INTERLACE_LAST
3983 # define check_interlace_type(type) ((void)(type))
3984 # define set_write_interlace_handling(pp,type) png_set_interlace_handling(pp)
3985 # define do_own_interlace 0
3986 #elif PNG_LIBPNG_VER < 10700
3987 # define set_write_interlace_handling(pp,type) (1)
3989 check_interlace_type(int const interlace_type)
3991 /* Prior to 1.7.0 libpng does not support the write of an interlaced image
3992 * unless PNG_WRITE_INTERLACING_SUPPORTED, even with do_interlace so the
3993 * code here does the pixel interlace itself, so:
3995 if (interlace_type != PNG_INTERLACE_NONE)
3997 /* This is an internal error - --interlace tests should be skipped, not
4000 fprintf(stderr, "pngvalid: no interlace support\n");
4004 # define INTERLACE_LAST (PNG_INTERLACE_NONE+1)
4005 # define do_own_interlace 0
4006 #else /* libpng 1.7+ */
4007 # define set_write_interlace_handling(pp,type)\
4008 npasses_from_interlace_type(pp,type)
4009 # define check_interlace_type(type) ((void)(type))
4010 # define INTERLACE_LAST PNG_INTERLACE_LAST
4011 # define do_own_interlace 1
4012 #endif /* WRITE_INTERLACING tests */
4014 #if PNG_LIBPNG_VER >= 10700 || defined PNG_WRITE_INTERLACING_SUPPORTED
4015 # define CAN_WRITE_INTERLACE 1
4017 # define CAN_WRITE_INTERLACE 0
4020 /* Do the same thing for read interlacing; this controls whether read tests do
4021 * their own de-interlace or use libpng.
4023 #ifdef PNG_READ_INTERLACING_SUPPORTED
4024 # define do_read_interlace 0
4025 #else /* no libpng read interlace support */
4026 # define do_read_interlace 1
4028 /* The following two routines use the PNG interlace support macros from
4029 * png.h to interlace or deinterlace rows.
4032 interlace_row(png_bytep buffer, png_const_bytep imageRow,
4033 unsigned int pixel_size, png_uint_32 w, int pass, int littleendian)
4035 png_uint_32 xin, xout, xstep;
4037 /* Note that this can, trivially, be optimized to a memcpy on pass 7, the
4038 * code is presented this way to make it easier to understand. In practice
4039 * consult the code in the libpng source to see other ways of doing this.
4041 * It is OK for buffer and imageRow to be identical, because 'xin' moves
4042 * faster than 'xout' and we copy up.
4044 xin = PNG_PASS_START_COL(pass);
4045 xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
4047 for (xout=0; xin<w; xin+=xstep)
4049 pixel_copy(buffer, xout, imageRow, xin, pixel_size, littleendian);
4054 #ifdef PNG_READ_SUPPORTED
4056 deinterlace_row(png_bytep buffer, png_const_bytep row,
4057 unsigned int pixel_size, png_uint_32 w, int pass, int littleendian)
4059 /* The inverse of the above, 'row' is part of row 'y' of the output image,
4060 * in 'buffer'. The image is 'w' wide and this is pass 'pass', distribute
4061 * the pixels of row into buffer and return the number written (to allow
4062 * this to be checked).
4064 png_uint_32 xin, xout, xstep;
4066 xout = PNG_PASS_START_COL(pass);
4067 xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
4069 for (xin=0; xout<w; xout+=xstep)
4071 pixel_copy(buffer, xout, row, xin, pixel_size, littleendian);
4075 #endif /* PNG_READ_SUPPORTED */
4077 /* Make a standardized image given an image colour type, bit depth and
4078 * interlace type. The standard images have a very restricted range of
4079 * rows and heights and are used for testing transforms rather than image
4080 * layout details. See make_size_images below for a way to make images
4081 * that test odd sizes along with the libpng interlace handling.
4083 #ifdef PNG_WRITE_FILTER_SUPPORTED
4085 choose_random_filter(png_structp pp, int start)
4087 /* Choose filters randomly except that on the very first row ensure that
4088 * there is at least one previous row filter.
4090 int filters = PNG_ALL_FILTERS & random_mod(256U);
4092 /* There may be no filters; skip the setting. */
4095 if (start && filters < PNG_FILTER_UP)
4096 filters |= PNG_FILTER_UP;
4098 png_set_filter(pp, 0/*method*/, filters);
4101 #else /* !WRITE_FILTER */
4102 # define choose_random_filter(pp, start) ((void)0)
4103 #endif /* !WRITE_FILTER */
4106 make_transform_image(png_store* const ps, png_byte const colour_type,
4107 png_byte const bit_depth, unsigned int palette_number,
4108 int interlace_type, png_const_charp name)
4112 check_interlace_type(interlace_type);
4117 png_structp pp = set_store_for_write(ps, &pi, name);
4120 /* In the event of a problem return control to the Catch statement below
4121 * to do the clean up - it is not possible to 'return' directly from a Try
4127 w = transform_width(pp, colour_type, bit_depth);
4128 h = transform_height(pp, colour_type, bit_depth);
4130 png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
4131 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
4133 #ifdef PNG_TEXT_SUPPORTED
4134 # if defined(PNG_READ_zTXt_SUPPORTED) && defined(PNG_WRITE_zTXt_SUPPORTED)
4135 # define TEXT_COMPRESSION PNG_TEXT_COMPRESSION_zTXt
4137 # define TEXT_COMPRESSION PNG_TEXT_COMPRESSION_NONE
4140 static char key[] = "image name"; /* must be writeable */
4143 char copy[FILE_NAME_SIZE];
4145 /* Use a compressed text string to test the correct interaction of text
4146 * compression and IDAT compression.
4148 text.compression = TEXT_COMPRESSION;
4150 /* Yuck: the text must be writable! */
4151 pos = safecat(copy, sizeof copy, 0, ps->wname);
4153 text.text_length = pos;
4154 text.itxt_length = 0;
4158 png_set_text(pp, pi, &text, 1);
4162 if (colour_type == 3) /* palette */
4163 init_standard_palette(ps, pp, pi, 1U << bit_depth, 1/*do tRNS*/);
4165 # ifdef PNG_WRITE_tRNS_SUPPORTED
4166 else if (palette_number)
4167 set_random_tRNS(pp, pi, colour_type, bit_depth);
4170 png_write_info(pp, pi);
4172 if (png_get_rowbytes(pp, pi) !=
4173 transform_rowsize(pp, colour_type, bit_depth))
4174 png_error(pp, "transform row size incorrect");
4178 /* Somewhat confusingly this must be called *after* png_write_info
4179 * because if it is called before, the information in *pp has not been
4180 * updated to reflect the interlaced image.
4182 int npasses = set_write_interlace_handling(pp, interlace_type);
4185 if (npasses != npasses_from_interlace_type(pp, interlace_type))
4186 png_error(pp, "write: png_set_interlace_handling failed");
4188 for (pass=0; pass<npasses; ++pass)
4192 /* do_own_interlace is a pre-defined boolean (a #define) which is
4193 * set if we have to work out the interlaced rows here.
4197 png_byte buffer[TRANSFORM_ROWMAX];
4199 transform_row(pp, buffer, colour_type, bit_depth, y);
4201 # if do_own_interlace
4202 /* If do_own_interlace *and* the image is interlaced we need a
4203 * reduced interlace row; this may be reduced to empty.
4205 if (interlace_type == PNG_INTERLACE_ADAM7)
4207 /* The row must not be written if it doesn't exist, notice
4208 * that there are two conditions here, either the row isn't
4209 * ever in the pass or the row would be but isn't wide
4210 * enough to contribute any pixels. In fact the wPass test
4211 * can be used to skip the whole y loop in this case.
4213 if (PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
4214 PNG_PASS_COLS(w, pass) > 0)
4215 interlace_row(buffer, buffer,
4216 bit_size(pp, colour_type, bit_depth), w, pass,
4217 0/*data always bigendian*/);
4221 # endif /* do_own_interlace */
4223 choose_random_filter(pp, pass == 0 && y == 0);
4224 png_write_row(pp, buffer);
4229 #ifdef PNG_TEXT_SUPPORTED
4231 static char key[] = "end marker";
4232 static char comment[] = "end";
4235 /* Use a compressed text string to test the correct interaction of text
4236 * compression and IDAT compression.
4238 text.compression = TEXT_COMPRESSION;
4240 text.text = comment;
4241 text.text_length = (sizeof comment)-1;
4242 text.itxt_length = 0;
4246 png_set_text(pp, pi, &text, 1);
4250 png_write_end(pp, pi);
4252 /* And store this under the appropriate id, then clean up. */
4253 store_storefile(ps, FILEID(colour_type, bit_depth, palette_number,
4254 interlace_type, 0, 0, 0));
4256 store_write_reset(ps);
4261 /* Use the png_store returned by the exception. This may help the compiler
4262 * because 'ps' is not used in this branch of the setjmp. Note that fault
4263 * and ps will always be the same value.
4265 store_write_reset(fault);
4270 make_transform_images(png_modifier *pm)
4272 png_byte colour_type = 0;
4273 png_byte bit_depth = 0;
4274 unsigned int palette_number = 0;
4276 /* This is in case of errors. */
4277 safecat(pm->this.test, sizeof pm->this.test, 0, "make standard images");
4279 /* Use next_format to enumerate all the combinations we test, including
4280 * generating multiple low bit depth palette images. Non-A images (palette
4281 * and direct) are created with and without tRNS chunks.
4283 while (next_format(&colour_type, &bit_depth, &palette_number, 1, 1))
4287 for (interlace_type = PNG_INTERLACE_NONE;
4288 interlace_type < INTERLACE_LAST; ++interlace_type)
4290 char name[FILE_NAME_SIZE];
4292 standard_name(name, sizeof name, 0, colour_type, bit_depth,
4293 palette_number, interlace_type, 0, 0, do_own_interlace);
4294 make_transform_image(&pm->this, colour_type, bit_depth, palette_number,
4295 interlace_type, name);
4300 /* Build a single row for the 'size' test images; this fills in only the
4301 * first bit_width bits of the sample row.
4304 size_row(png_byte buffer[SIZE_ROWMAX], png_uint_32 bit_width, png_uint_32 y)
4306 /* height is in the range 1 to 16, so: */
4307 y = ((y & 1) << 7) + ((y & 2) << 6) + ((y & 4) << 5) + ((y & 8) << 4);
4308 /* the following ensures bits are set in small images: */
4311 while (bit_width >= 8)
4312 *buffer++ = (png_byte)y++, bit_width -= 8;
4314 /* There may be up to 7 remaining bits, these go in the most significant
4319 png_uint_32 mask = (1U<<(8-bit_width))-1;
4320 *buffer = (png_byte)((*buffer & mask) | (y & ~mask));
4325 make_size_image(png_store* const ps, png_byte const colour_type,
4326 png_byte const bit_depth, int const interlace_type,
4327 png_uint_32 const w, png_uint_32 const h,
4328 int const do_interlace)
4332 check_interlace_type(interlace_type);
4338 unsigned int pixel_size;
4340 /* Make a name and get an appropriate id for the store: */
4341 char name[FILE_NAME_SIZE];
4342 png_uint_32 id = FILEID(colour_type, bit_depth, 0/*palette*/,
4343 interlace_type, w, h, do_interlace);
4345 standard_name_from_id(name, sizeof name, 0, id);
4346 pp = set_store_for_write(ps, &pi, name);
4348 /* In the event of a problem return control to the Catch statement below
4349 * to do the clean up - it is not possible to 'return' directly from a Try
4355 png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
4356 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
4358 #ifdef PNG_TEXT_SUPPORTED
4360 static char key[] = "image name"; /* must be writeable */
4363 char copy[FILE_NAME_SIZE];
4365 /* Use a compressed text string to test the correct interaction of text
4366 * compression and IDAT compression.
4368 text.compression = TEXT_COMPRESSION;
4370 /* Yuck: the text must be writable! */
4371 pos = safecat(copy, sizeof copy, 0, ps->wname);
4373 text.text_length = pos;
4374 text.itxt_length = 0;
4378 png_set_text(pp, pi, &text, 1);
4382 if (colour_type == 3) /* palette */
4383 init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
4385 png_write_info(pp, pi);
4387 /* Calculate the bit size, divide by 8 to get the byte size - this won't
4388 * overflow because we know the w values are all small enough even for
4389 * a system where 'unsigned int' is only 16 bits.
4391 pixel_size = bit_size(pp, colour_type, bit_depth);
4392 if (png_get_rowbytes(pp, pi) != ((w * pixel_size) + 7) / 8)
4393 png_error(pp, "size row size incorrect");
4397 int npasses = npasses_from_interlace_type(pp, interlace_type);
4400 png_byte image[16][SIZE_ROWMAX];
4402 /* To help consistent error detection make the parts of this buffer
4403 * that aren't set below all '1':
4405 memset(image, 0xff, sizeof image);
4407 if (!do_interlace &&
4408 npasses != set_write_interlace_handling(pp, interlace_type))
4409 png_error(pp, "write: png_set_interlace_handling failed");
4411 /* Prepare the whole image first to avoid making it 7 times: */
4413 size_row(image[y], w * pixel_size, y);
4415 for (pass=0; pass<npasses; ++pass)
4417 /* The following two are for checking the macros: */
4418 png_uint_32 wPass = PNG_PASS_COLS(w, pass);
4420 /* If do_interlace is set we don't call png_write_row for every
4421 * row because some of them are empty. In fact, for a 1x1 image,
4422 * most of them are empty!
4426 png_const_bytep row = image[y];
4427 png_byte tempRow[SIZE_ROWMAX];
4429 /* If do_interlace *and* the image is interlaced we
4430 * need a reduced interlace row; this may be reduced
4433 if (do_interlace && interlace_type == PNG_INTERLACE_ADAM7)
4435 /* The row must not be written if it doesn't exist, notice
4436 * that there are two conditions here, either the row isn't
4437 * ever in the pass or the row would be but isn't wide
4438 * enough to contribute any pixels. In fact the wPass test
4439 * can be used to skip the whole y loop in this case.
4441 if (PNG_ROW_IN_INTERLACE_PASS(y, pass) && wPass > 0)
4443 /* Set to all 1's for error detection (libpng tends to
4444 * set unset things to 0).
4446 memset(tempRow, 0xff, sizeof tempRow);
4447 interlace_row(tempRow, row, pixel_size, w, pass,
4448 0/*data always bigendian*/);
4455 # ifdef PNG_WRITE_FILTER_SUPPORTED
4456 /* Only get to here if the row has some pixels in it, set the
4457 * filters to 'all' for the very first row and thereafter to a
4458 * single filter. It isn't well documented, but png_set_filter
4459 * does accept a filter number (per the spec) as well as a bit
4462 * The code now uses filters at random, except that on the first
4463 * row of an image it ensures that a previous row filter is in
4464 * the set so that libpng allocates the row buffer.
4467 int filters = 8 << random_mod(PNG_FILTER_VALUE_LAST);
4469 if (pass == 0 && y == 0 &&
4470 (filters < PNG_FILTER_UP || w == 1U))
4471 filters |= PNG_FILTER_UP;
4473 png_set_filter(pp, 0/*method*/, filters);
4477 png_write_row(pp, row);
4482 #ifdef PNG_TEXT_SUPPORTED
4484 static char key[] = "end marker";
4485 static char comment[] = "end";
4488 /* Use a compressed text string to test the correct interaction of text
4489 * compression and IDAT compression.
4491 text.compression = TEXT_COMPRESSION;
4493 text.text = comment;
4494 text.text_length = (sizeof comment)-1;
4495 text.itxt_length = 0;
4499 png_set_text(pp, pi, &text, 1);
4503 png_write_end(pp, pi);
4505 /* And store this under the appropriate id, then clean up. */
4506 store_storefile(ps, id);
4508 store_write_reset(ps);
4513 /* Use the png_store returned by the exception. This may help the compiler
4514 * because 'ps' is not used in this branch of the setjmp. Note that fault
4515 * and ps will always be the same value.
4517 store_write_reset(fault);
4522 make_size(png_store* const ps, png_byte const colour_type, int bdlo,
4525 for (; bdlo <= bdhi; ++bdlo)
4529 for (width = 1; width <= 16; ++width)
4533 for (height = 1; height <= 16; ++height)
4535 /* The four combinations of DIY interlace and interlace or not -
4536 * no interlace + DIY should be identical to no interlace with
4539 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
4541 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
4543 # ifdef PNG_WRITE_INTERLACING_SUPPORTED
4544 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
4547 # if CAN_WRITE_INTERLACE
4548 /* 1.7.0 removes the hack that prevented app write of an interlaced
4549 * image if WRITE_INTERLACE was not supported
4551 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
4560 make_size_images(png_store *ps)
4562 /* This is in case of errors. */
4563 safecat(ps->test, sizeof ps->test, 0, "make size images");
4565 /* Arguments are colour_type, low bit depth, high bit depth
4567 make_size(ps, 0, 0, WRITE_BDHI);
4568 make_size(ps, 2, 3, WRITE_BDHI);
4569 make_size(ps, 3, 0, 3 /*palette: max 8 bits*/);
4570 make_size(ps, 4, 3, WRITE_BDHI);
4571 make_size(ps, 6, 3, WRITE_BDHI);
4574 #ifdef PNG_READ_SUPPORTED
4575 /* Return a row based on image id and 'y' for checking: */
4577 standard_row(png_const_structp pp, png_byte std[STANDARD_ROWMAX],
4578 png_uint_32 id, png_uint_32 y)
4580 if (WIDTH_FROM_ID(id) == 0)
4581 transform_row(pp, std, COL_FROM_ID(id), DEPTH_FROM_ID(id), y);
4583 size_row(std, WIDTH_FROM_ID(id) * bit_size(pp, COL_FROM_ID(id),
4584 DEPTH_FROM_ID(id)), y);
4586 #endif /* PNG_READ_SUPPORTED */
4588 /* Tests - individual test cases */
4589 /* Like 'make_standard' but errors are deliberately introduced into the calls
4590 * to ensure that they get detected - it should not be possible to write an
4591 * invalid image with libpng!
4593 /* TODO: the 'set' functions can probably all be made to take a
4594 * png_const_structp rather than a modifiable one.
4596 #ifdef PNG_WARNINGS_SUPPORTED
4598 sBIT0_error_fn(png_structp pp, png_infop pi)
4600 /* 0 is invalid... */
4602 bad.red = bad.green = bad.blue = bad.gray = bad.alpha = 0;
4603 png_set_sBIT(pp, pi, &bad);
4607 sBIT_error_fn(png_structp pp, png_infop pi)
4612 if (png_get_color_type(pp, pi) == PNG_COLOR_TYPE_PALETTE)
4616 bit_depth = png_get_bit_depth(pp, pi);
4618 /* Now we know the bit depth we can easily generate an invalid sBIT entry */
4619 bad.red = bad.green = bad.blue = bad.gray = bad.alpha =
4620 (png_byte)(bit_depth+1);
4621 png_set_sBIT(pp, pi, &bad);
4626 void (*fn)(png_structp, png_infop);
4628 unsigned int warning :1; /* the error is a warning... */
4631 /* no warnings makes these errors undetectable prior to 1.7.0 */
4632 { sBIT0_error_fn, "sBIT(0): failed to detect error",
4633 PNG_LIBPNG_VER < 10700 },
4635 { sBIT_error_fn, "sBIT(too big): failed to detect error",
4636 PNG_LIBPNG_VER < 10700 },
4640 make_error(png_store* const ps, png_byte const colour_type,
4641 png_byte bit_depth, int interlace_type, int test, png_const_charp name)
4645 check_interlace_type(interlace_type);
4650 png_structp pp = set_store_for_write(ps, &pi, name);
4657 w = transform_width(pp, colour_type, bit_depth);
4659 h = transform_height(pp, colour_type, bit_depth);
4661 png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
4662 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
4664 if (colour_type == 3) /* palette */
4665 init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
4667 /* Time for a few errors; these are in various optional chunks, the
4668 * standard tests test the standard chunks pretty well.
4670 # define exception__prev exception_prev_1
4671 # define exception__env exception_env_1
4674 gnu_volatile(exception__prev)
4676 /* Expect this to throw: */
4677 ps->expect_error = !error_test[test].warning;
4678 ps->expect_warning = error_test[test].warning;
4679 ps->saw_warning = 0;
4680 error_test[test].fn(pp, pi);
4682 /* Normally the error is only detected here: */
4683 png_write_info(pp, pi);
4685 /* And handle the case where it was only a warning: */
4686 if (ps->expect_warning && ps->saw_warning)
4689 /* If we get here there is a problem, we have success - no error or
4690 * no warning - when we shouldn't have success. Log an error.
4692 store_log(ps, pp, error_test[test].msg, 1 /*error*/);
4696 { /* expected exit */
4698 #undef exception__prev
4699 #undef exception__env
4701 /* And clear these flags */
4702 ps->expect_warning = 0;
4704 if (ps->expect_error)
4705 ps->expect_error = 0;
4709 /* Now write the whole image, just to make sure that the detected, or
4710 * undetected, error has not created problems inside libpng. This
4711 * doesn't work if there was a png_error in png_write_info because that
4712 * can abort before PLTE was written.
4714 if (png_get_rowbytes(pp, pi) !=
4715 transform_rowsize(pp, colour_type, bit_depth))
4716 png_error(pp, "row size incorrect");
4720 int npasses = set_write_interlace_handling(pp, interlace_type);
4723 if (npasses != npasses_from_interlace_type(pp, interlace_type))
4724 png_error(pp, "write: png_set_interlace_handling failed");
4726 for (pass=0; pass<npasses; ++pass)
4732 png_byte buffer[TRANSFORM_ROWMAX];
4734 transform_row(pp, buffer, colour_type, bit_depth, y);
4736 # if do_own_interlace
4737 /* If do_own_interlace *and* the image is interlaced we
4738 * need a reduced interlace row; this may be reduced to
4741 if (interlace_type == PNG_INTERLACE_ADAM7)
4743 /* The row must not be written if it doesn't exist,
4744 * notice that there are two conditions here, either the
4745 * row isn't ever in the pass or the row would be but
4746 * isn't wide enough to contribute any pixels. In fact
4747 * the wPass test can be used to skip the whole y loop
4750 if (PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
4751 PNG_PASS_COLS(w, pass) > 0)
4752 interlace_row(buffer, buffer,
4753 bit_size(pp, colour_type, bit_depth), w, pass,
4754 0/*data always bigendian*/);
4758 # endif /* do_own_interlace */
4760 png_write_row(pp, buffer);
4763 } /* image writing */
4765 png_write_end(pp, pi);
4768 /* The following deletes the file that was just written. */
4769 store_write_reset(ps);
4774 store_write_reset(fault);
4779 make_errors(png_modifier* const pm, png_byte const colour_type,
4780 int bdlo, int const bdhi)
4782 for (; bdlo <= bdhi; ++bdlo)
4786 for (interlace_type = PNG_INTERLACE_NONE;
4787 interlace_type < INTERLACE_LAST; ++interlace_type)
4790 char name[FILE_NAME_SIZE];
4792 standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
4793 interlace_type, 0, 0, do_own_interlace);
4795 for (test=0; test<ARRAY_SIZE(error_test); ++test)
4797 make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
4806 return 1; /* keep going */
4808 #endif /* PNG_WARNINGS_SUPPORTED */
4811 perform_error_test(png_modifier *pm)
4813 #ifdef PNG_WARNINGS_SUPPORTED /* else there are no cases that work! */
4814 /* Need to do this here because we just write in this test. */
4815 safecat(pm->this.test, sizeof pm->this.test, 0, "error test");
4817 if (!make_errors(pm, 0, 0, WRITE_BDHI))
4820 if (!make_errors(pm, 2, 3, WRITE_BDHI))
4823 if (!make_errors(pm, 3, 0, 3))
4826 if (!make_errors(pm, 4, 3, WRITE_BDHI))
4829 if (!make_errors(pm, 6, 3, WRITE_BDHI))
4836 /* This is just to validate the internal PNG formatting code - if this fails
4837 * then the warning messages the library outputs will probably be garbage.
4840 perform_formatting_test(png_store *ps)
4842 #ifdef PNG_TIME_RFC1123_SUPPORTED
4843 /* The handle into the formatting code is the RFC1123 support; this test does
4844 * nothing if that is compiled out.
4850 png_const_charp correct = "29 Aug 2079 13:53:60 +0000";
4851 png_const_charp result;
4852 # if PNG_LIBPNG_VER >= 10600
4853 char timestring[29];
4858 pp = set_store_for_write(ps, NULL, "libpng formatting test");
4864 /* Arbitrary settings: */
4870 pt.second = 60; /* a leap second */
4872 # if PNG_LIBPNG_VER < 10600
4873 result = png_convert_to_rfc1123(pp, &pt);
4875 if (png_convert_to_rfc1123_buffer(timestring, &pt))
4876 result = timestring;
4883 png_error(pp, "png_convert_to_rfc1123 failed");
4885 if (strcmp(result, correct) != 0)
4890 pos = safecat(msg, sizeof msg, pos, "png_convert_to_rfc1123(");
4891 pos = safecat(msg, sizeof msg, pos, correct);
4892 pos = safecat(msg, sizeof msg, pos, ") returned: '");
4893 pos = safecat(msg, sizeof msg, pos, result);
4894 pos = safecat(msg, sizeof msg, pos, "'");
4899 store_write_reset(ps);
4904 store_write_reset(fault);
4911 #ifdef PNG_READ_SUPPORTED
4912 /* Because we want to use the same code in both the progressive reader and the
4913 * sequential reader it is necessary to deal with the fact that the progressive
4914 * reader callbacks only have one parameter (png_get_progressive_ptr()), so this
4915 * must contain all the test parameters and all the local variables directly
4916 * accessible to the sequential reader implementation.
4918 * The technique adopted is to reinvent part of what Dijkstra termed a
4919 * 'display'; an array of pointers to the stack frames of enclosing functions so
4920 * that a nested function definition can access the local (C auto) variables of
4921 * the functions that contain its definition. In fact C provides the first
4922 * pointer (the local variables - the stack frame pointer) and the last (the
4923 * global variables - the BCPL global vector typically implemented as global
4924 * addresses), this code requires one more pointer to make the display - the
4925 * local variables (and function call parameters) of the function that actually
4926 * invokes either the progressive or sequential reader.
4928 * Perhaps confusingly this technique is confounded with classes - the
4929 * 'standard_display' defined here is sub-classed as the 'gamma_display' below.
4930 * A gamma_display is a standard_display, taking advantage of the ANSI-C
4931 * requirement that the pointer to the first member of a structure must be the
4932 * same as the pointer to the structure. This allows us to reuse standard_
4933 * functions in the gamma test code; something that could not be done with
4936 typedef struct standard_display
4938 png_store* ps; /* Test parameters (passed to the function) */
4939 png_byte colour_type;
4941 png_byte red_sBIT; /* Input data sBIT values. */
4942 png_byte green_sBIT;
4944 png_byte alpha_sBIT;
4945 png_byte interlace_type;
4946 png_byte filler; /* Output has a filler */
4947 png_uint_32 id; /* Calculated file ID */
4948 png_uint_32 w; /* Width of image */
4949 png_uint_32 h; /* Height of image */
4950 int npasses; /* Number of interlaced passes */
4951 png_uint_32 pixel_size; /* Width of one pixel in bits */
4952 png_uint_32 bit_width; /* Width of output row in bits */
4953 size_t cbRow; /* Bytes in a row of the output image */
4954 int do_interlace; /* Do interlacing internally */
4955 int littleendian; /* App (row) data is little endian */
4956 int is_transparent; /* Transparency information was present. */
4957 int has_tRNS; /* color type GRAY or RGB with a tRNS chunk. */
4958 int speed; /* Doing a speed test */
4959 int use_update_info;/* Call update_info, not start_image */
4965 } transparent; /* The transparent color, if set. */
4966 int npalette; /* Number of entries in the palette. */
4972 standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id,
4973 int do_interlace, int use_update_info)
4975 memset(dp, 0, sizeof *dp);
4978 dp->colour_type = COL_FROM_ID(id);
4979 dp->bit_depth = DEPTH_FROM_ID(id);
4980 if (dp->bit_depth < 1 || dp->bit_depth > 16)
4981 internal_error(ps, "internal: bad bit depth");
4982 if (dp->colour_type == 3)
4983 dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT = 8;
4985 dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT =
4987 dp->interlace_type = INTERLACE_FROM_ID(id);
4988 check_interlace_type(dp->interlace_type);
4990 /* All the rest are filled in after the read_info: */
4997 dp->do_interlace = do_interlace;
4998 dp->littleendian = 0;
4999 dp->is_transparent = 0;
5000 dp->speed = ps->speed;
5001 dp->use_update_info = use_update_info;
5003 /* Preset the transparent color to black: */
5004 memset(&dp->transparent, 0, sizeof dp->transparent);
5005 /* Preset the palette to full intensity/opaque throughout: */
5006 memset(dp->palette, 0xff, sizeof dp->palette);
5009 /* Initialize the palette fields - this must be done later because the palette
5010 * comes from the particular png_store_file that is selected.
5013 standard_palette_init(standard_display *dp)
5015 store_palette_entry *palette = store_current_palette(dp->ps, &dp->npalette);
5017 /* The remaining entries remain white/opaque. */
5018 if (dp->npalette > 0)
5020 int i = dp->npalette;
5021 memcpy(dp->palette, palette, i * sizeof *palette);
5023 /* Check for a non-opaque palette entry: */
5025 if (palette[i].alpha < 255)
5029 /* GCC can't handle the more obviously optimizable version. */
5031 dp->is_transparent = 1;
5033 dp->is_transparent = 0;
5035 dp->is_transparent = (i >= 0);
5040 /* Utility to read the palette from the PNG file and convert it into
5041 * store_palette format. This returns 1 if there is any transparency in the
5042 * palette (it does not check for a transparent colour in the non-palette case.)
5045 read_palette(store_palette palette, int *npalette, png_const_structp pp,
5049 png_bytep trans_alpha;
5055 if (png_get_PLTE(pp, pi, &pal, npalette) & PNG_INFO_PLTE)
5059 if (i <= 0 || i > 256)
5060 png_error(pp, "validate: invalid PLTE count");
5064 palette[i].red = pal[i].red;
5065 palette[i].green = pal[i].green;
5066 palette[i].blue = pal[i].blue;
5069 /* Mark the remainder of the entries with a flag value (other than
5070 * white/opaque which is the flag value stored above.)
5072 memset(palette + *npalette, 126, (256-*npalette) * sizeof *palette);
5075 else /* !png_get_PLTE */
5077 if (*npalette != (-1))
5078 png_error(pp, "validate: invalid PLTE result");
5079 /* But there is no palette, so record this: */
5081 memset(palette, 113, sizeof (store_palette));
5085 num = 2; /* force error below */
5086 if ((png_get_tRNS(pp, pi, &trans_alpha, &num, 0) & PNG_INFO_tRNS) != 0 &&
5087 (trans_alpha != NULL || num != 1/*returns 1 for a transparent color*/) &&
5088 /* Oops, if a palette tRNS gets expanded png_read_update_info (at least so
5089 * far as 1.5.4) does not remove the trans_alpha pointer, only num_trans,
5090 * so in the above call we get a success, we get a pointer (who knows what
5091 * to) and we get num_trans == 0:
5093 !(trans_alpha != NULL && num == 0)) /* TODO: fix this in libpng. */
5097 /* Any of these are crash-worthy - given the implementation of
5098 * png_get_tRNS up to 1.5 an app won't crash if it just checks the
5099 * result above and fails to check that the variables it passed have
5100 * actually been filled in! Note that if the app were to pass the
5101 * last, png_color_16p, variable too it couldn't rely on this.
5103 if (trans_alpha == NULL || num <= 0 || num > 256 || num > *npalette)
5104 png_error(pp, "validate: unexpected png_get_tRNS (palette) result");
5106 for (i=0; i<num; ++i)
5107 palette[i].alpha = trans_alpha[i];
5109 for (num=*npalette; i<num; ++i)
5110 palette[i].alpha = 255;
5113 palette[i].alpha = 33; /* flag value */
5115 return 1; /* transparency */
5120 /* No palette transparency - just set the alpha channel to opaque. */
5123 for (i=0, num=*npalette; i<num; ++i)
5124 palette[i].alpha = 255;
5127 palette[i].alpha = 55; /* flag value */
5129 return 0; /* no transparency */
5133 /* Utility to validate the palette if it should not have changed (the
5134 * non-transform case).
5137 standard_palette_validate(standard_display *dp, png_const_structp pp,
5141 store_palette palette;
5143 if (read_palette(palette, &npalette, pp, pi) != dp->is_transparent)
5144 png_error(pp, "validate: palette transparency changed");
5146 if (npalette != dp->npalette)
5151 pos = safecat(msg, sizeof msg, pos, "validate: palette size changed: ");
5152 pos = safecatn(msg, sizeof msg, pos, dp->npalette);
5153 pos = safecat(msg, sizeof msg, pos, " -> ");
5154 pos = safecatn(msg, sizeof msg, pos, npalette);
5159 int i = npalette; /* npalette is aliased */
5162 if (palette[i].red != dp->palette[i].red ||
5163 palette[i].green != dp->palette[i].green ||
5164 palette[i].blue != dp->palette[i].blue ||
5165 palette[i].alpha != dp->palette[i].alpha)
5166 png_error(pp, "validate: PLTE or tRNS chunk changed");
5170 /* By passing a 'standard_display' the progressive callbacks can be used
5171 * directly by the sequential code, the functions suffixed "_imp" are the
5172 * implementations, the functions without the suffix are the callbacks.
5174 * The code for the info callback is split into two because this callback calls
5175 * png_read_update_info or png_start_read_image and what gets called depends on
5176 * whether the info needs updating (we want to test both calls in pngvalid.)
5179 standard_info_part1(standard_display *dp, png_structp pp, png_infop pi)
5181 if (png_get_bit_depth(pp, pi) != dp->bit_depth)
5182 png_error(pp, "validate: bit depth changed");
5184 if (png_get_color_type(pp, pi) != dp->colour_type)
5185 png_error(pp, "validate: color type changed");
5187 if (png_get_filter_type(pp, pi) != PNG_FILTER_TYPE_BASE)
5188 png_error(pp, "validate: filter type changed");
5190 if (png_get_interlace_type(pp, pi) != dp->interlace_type)
5191 png_error(pp, "validate: interlacing changed");
5193 if (png_get_compression_type(pp, pi) != PNG_COMPRESSION_TYPE_BASE)
5194 png_error(pp, "validate: compression type changed");
5196 dp->w = png_get_image_width(pp, pi);
5198 if (dp->w != standard_width(pp, dp->id))
5199 png_error(pp, "validate: image width changed");
5201 dp->h = png_get_image_height(pp, pi);
5203 if (dp->h != standard_height(pp, dp->id))
5204 png_error(pp, "validate: image height changed");
5206 /* Record (but don't check at present) the input sBIT according to the colour
5210 png_color_8p sBIT = 0;
5212 if (png_get_sBIT(pp, pi, &sBIT) & PNG_INFO_sBIT)
5214 int sBIT_invalid = 0;
5217 png_error(pp, "validate: unexpected png_get_sBIT result");
5219 if (dp->colour_type & PNG_COLOR_MASK_COLOR)
5221 if (sBIT->red == 0 || sBIT->red > dp->bit_depth)
5224 dp->red_sBIT = sBIT->red;
5226 if (sBIT->green == 0 || sBIT->green > dp->bit_depth)
5229 dp->green_sBIT = sBIT->green;
5231 if (sBIT->blue == 0 || sBIT->blue > dp->bit_depth)
5234 dp->blue_sBIT = sBIT->blue;
5239 if (sBIT->gray == 0 || sBIT->gray > dp->bit_depth)
5242 dp->blue_sBIT = dp->green_sBIT = dp->red_sBIT = sBIT->gray;
5245 /* All 8 bits in tRNS for a palette image are significant - see the
5248 if (dp->colour_type & PNG_COLOR_MASK_ALPHA)
5250 if (sBIT->alpha == 0 || sBIT->alpha > dp->bit_depth)
5253 dp->alpha_sBIT = sBIT->alpha;
5257 png_error(pp, "validate: sBIT value out of range");
5261 /* Important: this is validating the value *before* any transforms have been
5262 * put in place. It doesn't matter for the standard tests, where there are
5263 * no transforms, but it does for other tests where rowbytes may change after
5264 * png_read_update_info.
5266 if (png_get_rowbytes(pp, pi) != standard_rowsize(pp, dp->id))
5267 png_error(pp, "validate: row size changed");
5269 /* Validate the colour type 3 palette (this can be present on other color
5272 standard_palette_validate(dp, pp, pi);
5274 /* In any case always check for a transparent color (notice that the
5275 * colour type 3 case must not give a successful return on the get_tRNS call
5276 * with these arguments!)
5279 png_color_16p trans_color = 0;
5281 if (png_get_tRNS(pp, pi, 0, 0, &trans_color) & PNG_INFO_tRNS)
5283 if (trans_color == 0)
5284 png_error(pp, "validate: unexpected png_get_tRNS (color) result");
5286 switch (dp->colour_type)
5289 dp->transparent.red = dp->transparent.green = dp->transparent.blue =
5295 dp->transparent.red = trans_color->red;
5296 dp->transparent.green = trans_color->green;
5297 dp->transparent.blue = trans_color->blue;
5302 /* Not expected because it should result in the array case
5305 png_error(pp, "validate: unexpected png_get_tRNS result");
5309 png_error(pp, "validate: invalid tRNS chunk with alpha image");
5314 /* Read the number of passes - expected to match the value used when
5315 * creating the image (interlaced or not). This has the side effect of
5316 * turning on interlace handling (if do_interlace is not set.)
5318 dp->npasses = npasses_from_interlace_type(pp, dp->interlace_type);
5319 if (!dp->do_interlace)
5321 # ifdef PNG_READ_INTERLACING_SUPPORTED
5322 if (dp->npasses != png_set_interlace_handling(pp))
5323 png_error(pp, "validate: file changed interlace type");
5324 # else /* !READ_INTERLACING */
5325 /* This should never happen: the relevant tests (!do_interlace) should
5328 if (dp->npasses > 1)
5329 png_error(pp, "validate: no libpng interlace support");
5330 # endif /* !READ_INTERLACING */
5333 /* Caller calls png_read_update_info or png_start_read_image now, then calls
5338 /* This must be called *after* the png_read_update_info call to get the correct
5339 * 'rowbytes' value, otherwise png_get_rowbytes will refer to the untransformed
5343 standard_info_part2(standard_display *dp, png_const_structp pp,
5344 png_const_infop pi, int nImages)
5346 /* Record cbRow now that it can be found. */
5348 png_byte ct = png_get_color_type(pp, pi);
5349 png_byte bd = png_get_bit_depth(pp, pi);
5351 if (bd >= 8 && (ct == PNG_COLOR_TYPE_RGB || ct == PNG_COLOR_TYPE_GRAY) &&
5353 ct |= 4; /* handle filler as faked alpha channel */
5355 dp->pixel_size = bit_size(pp, ct, bd);
5357 dp->bit_width = png_get_image_width(pp, pi) * dp->pixel_size;
5358 dp->cbRow = png_get_rowbytes(pp, pi);
5360 /* Validate the rowbytes here again. */
5361 if (dp->cbRow != (dp->bit_width+7)/8)
5362 png_error(pp, "bad png_get_rowbytes calculation");
5364 /* Then ensure there is enough space for the output image(s). */
5365 store_ensure_image(dp->ps, pp, nImages, dp->cbRow, dp->h);
5369 standard_info_imp(standard_display *dp, png_structp pp, png_infop pi,
5372 /* Note that the validation routine has the side effect of turning on
5373 * interlace handling in the subsequent code.
5375 standard_info_part1(dp, pp, pi);
5377 /* And the info callback has to call this (or png_read_update_info - see
5378 * below in the png_modifier code for that variant.
5380 if (dp->use_update_info)
5382 /* For debugging the effect of multiple calls: */
5383 int i = dp->use_update_info;
5385 png_read_update_info(pp, pi);
5389 png_start_read_image(pp);
5391 /* Validate the height, width and rowbytes plus ensure that sufficient buffer
5392 * exists for decoding the image.
5394 standard_info_part2(dp, pp, pi, nImages);
5397 static void PNGCBAPI
5398 standard_info(png_structp pp, png_infop pi)
5400 standard_display *dp = voidcast(standard_display*,
5401 png_get_progressive_ptr(pp));
5403 /* Call with nImages==1 because the progressive reader can only produce one
5406 standard_info_imp(dp, pp, pi, 1 /*only one image*/);
5409 static void PNGCBAPI
5410 progressive_row(png_structp ppIn, png_bytep new_row, png_uint_32 y, int pass)
5412 png_const_structp pp = ppIn;
5413 const standard_display *dp = voidcast(standard_display*,
5414 png_get_progressive_ptr(pp));
5416 /* When handling interlacing some rows will be absent in each pass, the
5417 * callback still gets called, but with a NULL pointer. This is checked
5418 * in the 'else' clause below. We need our own 'cbRow', but we can't call
5419 * png_get_rowbytes because we got no info structure.
5421 if (new_row != NULL)
5425 /* In the case where the reader doesn't do the interlace it gives
5426 * us the y in the sub-image:
5428 if (dp->do_interlace && dp->interlace_type == PNG_INTERLACE_ADAM7)
5430 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
5431 /* Use this opportunity to validate the png 'current' APIs: */
5432 if (y != png_get_current_row_number(pp))
5433 png_error(pp, "png_get_current_row_number is broken");
5435 if (pass != png_get_current_pass_number(pp))
5436 png_error(pp, "png_get_current_pass_number is broken");
5437 #endif /* USER_TRANSFORM_INFO */
5439 y = PNG_ROW_FROM_PASS_ROW(y, pass);
5442 /* Validate this just in case. */
5444 png_error(pp, "invalid y to progressive row callback");
5446 row = store_image_row(dp->ps, pp, 0, y);
5448 /* Combine the new row into the old: */
5449 #ifdef PNG_READ_INTERLACING_SUPPORTED
5450 if (dp->do_interlace)
5451 #endif /* READ_INTERLACING */
5453 if (dp->interlace_type == PNG_INTERLACE_ADAM7)
5454 deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass,
5457 row_copy(row, new_row, dp->pixel_size * dp->w, dp->littleendian);
5459 #ifdef PNG_READ_INTERLACING_SUPPORTED
5461 png_progressive_combine_row(pp, row, new_row);
5462 #endif /* PNG_READ_INTERLACING_SUPPORTED */
5465 else if (dp->interlace_type == PNG_INTERLACE_ADAM7 &&
5466 PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
5467 PNG_PASS_COLS(dp->w, pass) > 0)
5468 png_error(pp, "missing row in progressive de-interlacing");
5472 sequential_row(standard_display *dp, png_structp pp, png_infop pi,
5473 int iImage, int iDisplay)
5475 int npasses = dp->npasses;
5476 int do_interlace = dp->do_interlace &&
5477 dp->interlace_type == PNG_INTERLACE_ADAM7;
5478 png_uint_32 height = standard_height(pp, dp->id);
5479 png_uint_32 width = standard_width(pp, dp->id);
5480 const png_store* ps = dp->ps;
5483 for (pass=0; pass<npasses; ++pass)
5486 png_uint_32 wPass = PNG_PASS_COLS(width, pass);
5488 for (y=0; y<height; ++y)
5492 /* wPass may be zero or this row may not be in this pass.
5493 * png_read_row must not be called in either case.
5495 if (wPass > 0 && PNG_ROW_IN_INTERLACE_PASS(y, pass))
5497 /* Read the row into a pair of temporary buffers, then do the
5498 * merge here into the output rows.
5500 png_byte row[STANDARD_ROWMAX], display[STANDARD_ROWMAX];
5502 /* The following aids (to some extent) error detection - we can
5503 * see where png_read_row wrote. Use opposite values in row and
5504 * display to make this easier. Don't use 0xff (which is used in
5505 * the image write code to fill unused bits) or 0 (which is a
5506 * likely value to overwrite unused bits with).
5508 memset(row, 0xc5, sizeof row);
5509 memset(display, 0x5c, sizeof display);
5511 png_read_row(pp, row, display);
5514 deinterlace_row(store_image_row(ps, pp, iImage, y), row,
5515 dp->pixel_size, dp->w, pass, dp->littleendian);
5518 deinterlace_row(store_image_row(ps, pp, iDisplay, y), display,
5519 dp->pixel_size, dp->w, pass, dp->littleendian);
5524 iImage >= 0 ? store_image_row(ps, pp, iImage, y) : NULL,
5525 iDisplay >= 0 ? store_image_row(ps, pp, iDisplay, y) : NULL);
5529 /* And finish the read operation (only really necessary if the caller wants
5530 * to find additional data in png_info from chunks after the last IDAT.)
5532 png_read_end(pp, pi);
5535 #ifdef PNG_TEXT_SUPPORTED
5537 standard_check_text(png_const_structp pp, png_const_textp tp,
5538 png_const_charp keyword, png_const_charp text)
5541 size_t pos = safecat(msg, sizeof msg, 0, "text: ");
5544 pos = safecat(msg, sizeof msg, pos, keyword);
5545 pos = safecat(msg, sizeof msg, pos, ": ");
5548 if (tp->compression != TEXT_COMPRESSION)
5552 sprintf(buf, "compression [%d->%d], ", TEXT_COMPRESSION,
5554 pos = safecat(msg, sizeof msg, pos, buf);
5557 if (tp->key == NULL || strcmp(tp->key, keyword) != 0)
5559 pos = safecat(msg, sizeof msg, pos, "keyword \"");
5560 if (tp->key != NULL)
5562 pos = safecat(msg, sizeof msg, pos, tp->key);
5563 pos = safecat(msg, sizeof msg, pos, "\", ");
5567 pos = safecat(msg, sizeof msg, pos, "null, ");
5570 if (tp->text == NULL)
5571 pos = safecat(msg, sizeof msg, pos, "text lost, ");
5575 if (tp->text_length != strlen(text))
5578 sprintf(buf, "text length changed[%lu->%lu], ",
5579 (unsigned long)strlen(text), (unsigned long)tp->text_length);
5580 pos = safecat(msg, sizeof msg, pos, buf);
5583 if (strcmp(tp->text, text) != 0)
5585 pos = safecat(msg, sizeof msg, pos, "text becomes \"");
5586 pos = safecat(msg, sizeof msg, pos, tp->text);
5587 pos = safecat(msg, sizeof msg, pos, "\" (was \"");
5588 pos = safecat(msg, sizeof msg, pos, text);
5589 pos = safecat(msg, sizeof msg, pos, "\"), ");
5593 if (tp->itxt_length != 0)
5594 pos = safecat(msg, sizeof msg, pos, "iTXt length set, ");
5596 if (tp->lang != NULL)
5598 pos = safecat(msg, sizeof msg, pos, "iTXt language \"");
5599 pos = safecat(msg, sizeof msg, pos, tp->lang);
5600 pos = safecat(msg, sizeof msg, pos, "\", ");
5603 if (tp->lang_key != NULL)
5605 pos = safecat(msg, sizeof msg, pos, "iTXt keyword \"");
5606 pos = safecat(msg, sizeof msg, pos, tp->lang_key);
5607 pos = safecat(msg, sizeof msg, pos, "\", ");
5612 msg[pos-2] = '\0'; /* Remove the ", " at the end */
5618 standard_text_validate(standard_display *dp, png_const_structp pp,
5619 png_infop pi, int check_end)
5621 png_textp tp = NULL;
5622 png_uint_32 num_text = png_get_text(pp, pi, &tp, NULL);
5624 if (num_text == 2 && tp != NULL)
5626 standard_check_text(pp, tp, "image name", dp->ps->current->name);
5628 /* This exists because prior to 1.5.18 the progressive reader left the
5629 * png_struct z_stream unreset at the end of the image, so subsequent
5630 * attempts to use it simply returns Z_STREAM_END.
5633 standard_check_text(pp, tp+1, "end marker", "end");
5640 sprintf(msg, "expected two text items, got %lu",
5641 (unsigned long)num_text);
5646 # define standard_text_validate(dp,pp,pi,check_end) ((void)0)
5650 standard_row_validate(standard_display *dp, png_const_structp pp,
5651 int iImage, int iDisplay, png_uint_32 y)
5654 png_byte std[STANDARD_ROWMAX];
5656 /* The row must be pre-initialized to the magic number here for the size
5659 memset(std, 178, sizeof std);
5660 standard_row(pp, std, dp->id, y);
5662 /* At the end both the 'row' and 'display' arrays should end up identical.
5663 * In earlier passes 'row' will be partially filled in, with only the pixels
5664 * that have been read so far, but 'display' will have those pixels
5665 * replicated to fill the unread pixels while reading an interlaced image.
5668 (where = pixel_cmp(std, store_image_row(dp->ps, pp, iImage, y),
5669 dp->bit_width)) != 0)
5672 sprintf(msg, "PNG image row[%lu][%d] changed from %.2x to %.2x",
5673 (unsigned long)y, where-1, std[where-1],
5674 store_image_row(dp->ps, pp, iImage, y)[where-1]);
5678 if (iDisplay >= 0 &&
5679 (where = pixel_cmp(std, store_image_row(dp->ps, pp, iDisplay, y),
5680 dp->bit_width)) != 0)
5683 sprintf(msg, "display row[%lu][%d] changed from %.2x to %.2x",
5684 (unsigned long)y, where-1, std[where-1],
5685 store_image_row(dp->ps, pp, iDisplay, y)[where-1]);
5691 standard_image_validate(standard_display *dp, png_const_structp pp, int iImage,
5697 store_image_check(dp->ps, pp, iImage);
5700 store_image_check(dp->ps, pp, iDisplay);
5702 for (y=0; y<dp->h; ++y)
5703 standard_row_validate(dp, pp, iImage, iDisplay, y);
5705 /* This avoids false positives if the validation code is never called! */
5706 dp->ps->validated = 1;
5709 static void PNGCBAPI
5710 standard_end(png_structp ppIn, png_infop pi)
5712 png_const_structp pp = ppIn;
5713 standard_display *dp = voidcast(standard_display*,
5714 png_get_progressive_ptr(pp));
5718 /* Validate the image - progressive reading only produces one variant for
5719 * interlaced images.
5721 standard_text_validate(dp, pp, pi,
5722 PNG_LIBPNG_VER >= 10518/*check_end: see comments above*/);
5723 standard_image_validate(dp, pp, 0, -1);
5726 /* A single test run checking the standard image to ensure it is not damaged. */
5728 standard_test(png_store* const psIn, png_uint_32 const id,
5729 int do_interlace, int use_update_info)
5732 context(psIn, fault);
5734 /* Set up the display (stack frame) variables from the arguments to the
5735 * function and initialize the locals that are filled in later.
5737 standard_display_init(&d, psIn, id, do_interlace, use_update_info);
5739 /* Everything is protected by a Try/Catch. The functions called also
5740 * typically have local Try/Catch blocks.
5747 /* Get a png_struct for reading the image. This will throw an error if it
5748 * fails, so we don't need to check the result.
5750 pp = set_store_for_read(d.ps, &pi, d.id,
5751 d.do_interlace ? (d.ps->progressive ?
5752 "pngvalid progressive deinterlacer" :
5753 "pngvalid sequential deinterlacer") : (d.ps->progressive ?
5754 "progressive reader" : "sequential reader"));
5756 /* Initialize the palette correctly from the png_store_file. */
5757 standard_palette_init(&d);
5759 /* Introduce the correct read function. */
5760 if (d.ps->progressive)
5762 png_set_progressive_read_fn(pp, &d, standard_info, progressive_row,
5765 /* Now feed data into the reader until we reach the end: */
5766 store_progressive_read(d.ps, pp, pi);
5770 /* Note that this takes the store, not the display. */
5771 png_set_read_fn(pp, d.ps, store_read);
5773 /* Check the header values: */
5774 png_read_info(pp, pi);
5776 /* The code tests both versions of the images that the sequential
5777 * reader can produce.
5779 standard_info_imp(&d, pp, pi, 2 /*images*/);
5781 /* Need the total bytes in the image below; we can't get to this point
5782 * unless the PNG file values have been checked against the expected
5786 sequential_row(&d, pp, pi, 0, 1);
5788 /* After the last pass loop over the rows again to check that the
5793 standard_text_validate(&d, pp, pi, 1/*check_end*/);
5794 standard_image_validate(&d, pp, 0, 1);
5797 d.ps->validated = 1;
5801 /* Check for validation. */
5802 if (!d.ps->validated)
5803 png_error(pp, "image read failed silently");
5805 /* Successful completion. */
5809 d.ps = fault; /* make sure this hasn't been clobbered. */
5811 /* In either case clean up the store. */
5812 store_read_reset(d.ps);
5816 test_standard(png_modifier* const pm, png_byte const colour_type,
5817 int bdlo, int const bdhi)
5819 for (; bdlo <= bdhi; ++bdlo)
5823 for (interlace_type = PNG_INTERLACE_NONE;
5824 interlace_type < INTERLACE_LAST; ++interlace_type)
5826 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
5827 0/*palette*/, interlace_type, 0, 0, 0), do_read_interlace,
5828 pm->use_update_info);
5835 return 1; /* keep going */
5839 perform_standard_test(png_modifier *pm)
5841 /* Test each colour type over the valid range of bit depths (expressed as
5842 * log2(bit_depth) in turn, stop as soon as any error is detected.
5844 if (!test_standard(pm, 0, 0, READ_BDHI))
5847 if (!test_standard(pm, 2, 3, READ_BDHI))
5850 if (!test_standard(pm, 3, 0, 3))
5853 if (!test_standard(pm, 4, 3, READ_BDHI))
5856 if (!test_standard(pm, 6, 3, READ_BDHI))
5861 /********************************** SIZE TESTS ********************************/
5863 test_size(png_modifier* const pm, png_byte const colour_type,
5864 int bdlo, int const bdhi)
5866 /* Run the tests on each combination.
5868 * NOTE: on my 32 bit x86 each of the following blocks takes
5869 * a total of 3.5 seconds if done across every combo of bit depth
5870 * width and height. This is a waste of time in practice, hence the
5871 * hinc and winc stuff:
5873 static const png_byte hinc[] = {1, 3, 11, 1, 5};
5874 static const png_byte winc[] = {1, 9, 5, 7, 1};
5875 int save_bdlo = bdlo;
5877 for (; bdlo <= bdhi; ++bdlo)
5881 for (h=1; h<=16; h+=hinc[bdlo])
5883 for (w=1; w<=16; w+=winc[bdlo])
5885 /* First test all the 'size' images against the sequential
5886 * reader using libpng to deinterlace (where required.) This
5887 * validates the write side of libpng. There are four possibilities
5890 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
5891 0/*palette*/, PNG_INTERLACE_NONE, w, h, 0), 0/*do_interlace*/,
5892 pm->use_update_info);
5897 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
5898 0/*palette*/, PNG_INTERLACE_NONE, w, h, 1), 0/*do_interlace*/,
5899 pm->use_update_info);
5904 /* Now validate the interlaced read side - do_interlace true,
5905 * in the progressive case this does actually make a difference
5906 * to the code used in the non-interlaced case too.
5908 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
5909 0/*palette*/, PNG_INTERLACE_NONE, w, h, 0), 1/*do_interlace*/,
5910 pm->use_update_info);
5915 # if CAN_WRITE_INTERLACE
5916 /* Validate the pngvalid code itself: */
5917 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
5918 0/*palette*/, PNG_INTERLACE_ADAM7, w, h, 1), 1/*do_interlace*/,
5919 pm->use_update_info);
5928 /* Now do the tests of libpng interlace handling, after we have made sure
5929 * that the pngvalid version works:
5931 for (bdlo = save_bdlo; bdlo <= bdhi; ++bdlo)
5935 for (h=1; h<=16; h+=hinc[bdlo])
5937 for (w=1; w<=16; w+=winc[bdlo])
5939 # ifdef PNG_READ_INTERLACING_SUPPORTED
5940 /* Test with pngvalid generated interlaced images first; we have
5941 * already verify these are ok (unless pngvalid has self-consistent
5942 * read/write errors, which is unlikely), so this detects errors in
5943 * the read side first:
5945 # if CAN_WRITE_INTERLACE
5946 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
5947 0/*palette*/, PNG_INTERLACE_ADAM7, w, h, 1), 0/*do_interlace*/,
5948 pm->use_update_info);
5953 # endif /* READ_INTERLACING */
5955 # ifdef PNG_WRITE_INTERLACING_SUPPORTED
5956 /* Test the libpng write side against the pngvalid read side: */
5957 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
5958 0/*palette*/, PNG_INTERLACE_ADAM7, w, h, 0), 1/*do_interlace*/,
5959 pm->use_update_info);
5965 # ifdef PNG_READ_INTERLACING_SUPPORTED
5966 # ifdef PNG_WRITE_INTERLACING_SUPPORTED
5967 /* Test both together: */
5968 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo),
5969 0/*palette*/, PNG_INTERLACE_ADAM7, w, h, 0), 0/*do_interlace*/,
5970 pm->use_update_info);
5975 # endif /* READ_INTERLACING */
5980 return 1; /* keep going */
5984 perform_size_test(png_modifier *pm)
5986 /* Test each colour type over the valid range of bit depths (expressed as
5987 * log2(bit_depth) in turn, stop as soon as any error is detected.
5989 if (!test_size(pm, 0, 0, READ_BDHI))
5992 if (!test_size(pm, 2, 3, READ_BDHI))
5995 /* For the moment don't do the palette test - it's a waste of time when
5996 * compared to the grayscale test.
5999 if (!test_size(pm, 3, 0, 3))
6003 if (!test_size(pm, 4, 3, READ_BDHI))
6006 if (!test_size(pm, 6, 3, READ_BDHI))
6011 /******************************* TRANSFORM TESTS ******************************/
6012 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
6013 /* A set of tests to validate libpng image transforms. The possibilities here
6014 * are legion because the transforms can be combined in a combinatorial
6015 * fashion. To deal with this some measure of restraint is required, otherwise
6016 * the tests would take forever.
6018 typedef struct image_pixel
6020 /* A local (pngvalid) representation of a PNG pixel, in all its
6023 unsigned int red, green, blue, alpha; /* For non-palette images. */
6024 unsigned int palette_index; /* For a palette image. */
6025 png_byte colour_type; /* As in the spec. */
6026 png_byte bit_depth; /* Defines bit size in row */
6027 png_byte sample_depth; /* Scale of samples */
6028 unsigned int have_tRNS :1; /* tRNS chunk may need processing */
6029 unsigned int swap_rgb :1; /* RGB swapped to BGR */
6030 unsigned int alpha_first :1; /* Alpha at start, not end */
6031 unsigned int alpha_inverted :1; /* Alpha channel inverted */
6032 unsigned int mono_inverted :1; /* Gray channel inverted */
6033 unsigned int swap16 :1; /* Byte swap 16-bit components */
6034 unsigned int littleendian :1; /* High bits on right */
6035 unsigned int sig_bits :1; /* Pixel shifted (sig bits only) */
6037 /* For checking the code calculates double precision floating point values
6038 * along with an error value, accumulated from the transforms. Because an
6039 * sBIT setting allows larger error bounds (indeed, by the spec, apparently
6040 * up to just less than +/-1 in the scaled value) the *lowest* sBIT for each
6041 * channel is stored. This sBIT value is folded in to the stored error value
6042 * at the end of the application of the transforms to the pixel.
6044 * If sig_bits is set above the red, green, blue and alpha values have been
6045 * scaled so they only contain the significant bits of the component values.
6047 double redf, greenf, bluef, alphaf;
6048 double rede, greene, bluee, alphae;
6049 png_byte red_sBIT, green_sBIT, blue_sBIT, alpha_sBIT;
6052 /* Shared utility function, see below. */
6054 image_pixel_setf(image_pixel *this, unsigned int rMax, unsigned int gMax,
6055 unsigned int bMax, unsigned int aMax)
6057 this->redf = this->red / (double)rMax;
6058 this->greenf = this->green / (double)gMax;
6059 this->bluef = this->blue / (double)bMax;
6060 this->alphaf = this->alpha / (double)aMax;
6062 if (this->red < rMax)
6063 this->rede = this->redf * DBL_EPSILON;
6066 if (this->green < gMax)
6067 this->greene = this->greenf * DBL_EPSILON;
6070 if (this->blue < bMax)
6071 this->bluee = this->bluef * DBL_EPSILON;
6074 if (this->alpha < aMax)
6075 this->alphae = this->alphaf * DBL_EPSILON;
6080 /* Initialize the structure for the next pixel - call this before doing any
6081 * transforms and call it for each pixel since all the fields may need to be
6085 image_pixel_init(image_pixel *this, png_const_bytep row, png_byte colour_type,
6086 png_byte bit_depth, png_uint_32 x, store_palette palette,
6087 const image_pixel *format /*from pngvalid transform of input*/)
6089 png_byte sample_depth =
6090 (png_byte)(colour_type == PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth);
6091 unsigned int max = (1U<<sample_depth)-1;
6092 int swap16 = (format != 0 && format->swap16);
6093 int littleendian = (format != 0 && format->littleendian);
6094 int sig_bits = (format != 0 && format->sig_bits);
6096 /* Initially just set everything to the same number and the alpha to opaque.
6097 * Note that this currently assumes a simple palette where entry x has colour
6100 this->palette_index = this->red = this->green = this->blue =
6101 sample(row, colour_type, bit_depth, x, 0, swap16, littleendian);
6103 this->red_sBIT = this->green_sBIT = this->blue_sBIT = this->alpha_sBIT =
6106 /* Then override as appropriate: */
6107 if (colour_type == 3) /* palette */
6109 /* This permits the caller to default to the sample value. */
6112 unsigned int i = this->palette_index;
6114 this->red = palette[i].red;
6115 this->green = palette[i].green;
6116 this->blue = palette[i].blue;
6117 this->alpha = palette[i].alpha;
6121 else /* not palette */
6125 if ((colour_type & 4) != 0 && format != 0 && format->alpha_first)
6127 this->alpha = this->red;
6128 /* This handles the gray case for 'AG' pixels */
6129 this->palette_index = this->red = this->green = this->blue =
6130 sample(row, colour_type, bit_depth, x, 1, swap16, littleendian);
6134 if (colour_type & 2)
6136 /* Green is second for both BGR and RGB: */
6137 this->green = sample(row, colour_type, bit_depth, x, ++i, swap16,
6140 if (format != 0 && format->swap_rgb) /* BGR */
6141 this->red = sample(row, colour_type, bit_depth, x, ++i, swap16,
6144 this->blue = sample(row, colour_type, bit_depth, x, ++i, swap16,
6148 else /* grayscale */ if (format != 0 && format->mono_inverted)
6149 this->red = this->green = this->blue = this->red ^ max;
6151 if ((colour_type & 4) != 0) /* alpha */
6153 if (format == 0 || !format->alpha_first)
6154 this->alpha = sample(row, colour_type, bit_depth, x, ++i, swap16,
6157 if (format != 0 && format->alpha_inverted)
6162 /* Calculate the scaled values, these are simply the values divided by
6163 * 'max' and the error is initialized to the double precision epsilon value
6164 * from the header file.
6166 image_pixel_setf(this,
6167 sig_bits ? (1U << format->red_sBIT)-1 : max,
6168 sig_bits ? (1U << format->green_sBIT)-1 : max,
6169 sig_bits ? (1U << format->blue_sBIT)-1 : max,
6170 sig_bits ? (1U << format->alpha_sBIT)-1 : max);
6172 /* Store the input information for use in the transforms - these will
6173 * modify the information.
6175 this->colour_type = colour_type;
6176 this->bit_depth = bit_depth;
6177 this->sample_depth = sample_depth;
6178 this->have_tRNS = 0;
6180 this->alpha_first = 0;
6181 this->alpha_inverted = 0;
6182 this->mono_inverted = 0;
6184 this->littleendian = 0;
6188 #if defined PNG_READ_EXPAND_SUPPORTED || defined PNG_READ_GRAY_TO_RGB_SUPPORTED\
6189 || defined PNG_READ_EXPAND_SUPPORTED || defined PNG_READ_EXPAND_16_SUPPORTED\
6190 || defined PNG_READ_BACKGROUND_SUPPORTED
6191 /* Convert a palette image to an rgb image. This necessarily converts the tRNS
6192 * chunk at the same time, because the tRNS will be in palette form. The way
6193 * palette validation works means that the original palette is never updated,
6194 * instead the image_pixel value from the row contains the RGB of the
6195 * corresponding palette entry and *this* is updated. Consequently this routine
6196 * only needs to change the colour type information.
6199 image_pixel_convert_PLTE(image_pixel *this)
6201 if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
6203 if (this->have_tRNS)
6205 this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
6206 this->have_tRNS = 0;
6209 this->colour_type = PNG_COLOR_TYPE_RGB;
6211 /* The bit depth of the row changes at this point too (notice that this is
6212 * the row format, not the sample depth, which is separate.)
6214 this->bit_depth = 8;
6218 /* Add an alpha channel; this will import the tRNS information because tRNS is
6219 * not valid in an alpha image. The bit depth will invariably be set to at
6220 * least 8 prior to 1.7.0. Palette images will be converted to alpha (using
6221 * the above API). With png_set_background the alpha channel is never expanded
6222 * but this routine is used by pngvalid to simplify code; 'for_background'
6226 image_pixel_add_alpha(image_pixel *this, const standard_display *display,
6229 if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
6230 image_pixel_convert_PLTE(this);
6232 if ((this->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
6234 if (this->colour_type == PNG_COLOR_TYPE_GRAY)
6236 # if PNG_LIBPNG_VER < 10700
6237 if (!for_background && this->bit_depth < 8)
6238 this->bit_depth = this->sample_depth = 8;
6241 if (this->have_tRNS)
6243 /* After 1.7 the expansion of bit depth only happens if there is a
6244 * tRNS chunk to expand at this point.
6246 # if PNG_LIBPNG_VER >= 10700
6247 if (!for_background && this->bit_depth < 8)
6248 this->bit_depth = this->sample_depth = 8;
6251 this->have_tRNS = 0;
6253 /* Check the input, original, channel value here against the
6254 * original tRNS gray chunk valie.
6256 if (this->red == display->transparent.red)
6264 this->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
6267 else if (this->colour_type == PNG_COLOR_TYPE_RGB)
6269 if (this->have_tRNS)
6271 this->have_tRNS = 0;
6273 /* Again, check the exact input values, not the current transformed
6276 if (this->red == display->transparent.red &&
6277 this->green == display->transparent.green &&
6278 this->blue == display->transparent.blue)
6286 this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
6289 /* The error in the alpha is zero and the sBIT value comes from the
6290 * original sBIT data (actually it will always be the original bit depth).
6293 this->alpha_sBIT = display->alpha_sBIT;
6296 #endif /* transforms that need image_pixel_add_alpha */
6298 struct transform_display;
6299 typedef struct image_transform
6301 /* The name of this transform: a string. */
6304 /* Each transform can be disabled from the command line: */
6307 /* The global list of transforms; read only. */
6308 struct image_transform *const list;
6310 /* The global count of the number of times this transform has been set on an
6313 unsigned int global_use;
6315 /* The local count of the number of times this transform has been set. */
6316 unsigned int local_use;
6318 /* The next transform in the list, each transform must call its own next
6319 * transform after it has processed the pixel successfully.
6321 const struct image_transform *next;
6323 /* A single transform for the image, expressed as a series of function
6324 * callbacks and some space for values.
6326 * First a callback to add any required modifications to the png_modifier;
6327 * this gets called just before the modifier is set up for read.
6329 void (*ini)(const struct image_transform *this,
6330 struct transform_display *that);
6332 /* And a callback to set the transform on the current png_read_struct:
6334 void (*set)(const struct image_transform *this,
6335 struct transform_display *that, png_structp pp, png_infop pi);
6337 /* Then a transform that takes an input pixel in one PNG format or another
6338 * and modifies it by a pngvalid implementation of the transform (thus
6339 * duplicating the libpng intent without, we hope, duplicating the bugs
6340 * in the libpng implementation!) The png_structp is solely to allow error
6341 * reporting via png_error and png_warning.
6343 void (*mod)(const struct image_transform *this, image_pixel *that,
6344 png_const_structp pp, const struct transform_display *display);
6346 /* Add this transform to the list and return true if the transform is
6347 * meaningful for this colour type and bit depth - if false then the
6348 * transform should have no effect on the image so there's not a lot of
6351 int (*add)(struct image_transform *this,
6352 const struct image_transform **that, png_byte colour_type,
6353 png_byte bit_depth);
6356 typedef struct transform_display
6358 standard_display this;
6362 const image_transform* transform_list;
6363 unsigned int max_gamma_8;
6365 /* Local variables */
6366 png_byte output_colour_type;
6367 png_byte output_bit_depth;
6370 /* Modifications (not necessarily used.) */
6371 gama_modification gama_mod;
6372 chrm_modification chrm_mod;
6373 srgb_modification srgb_mod;
6374 } transform_display;
6376 /* Set sRGB, cHRM and gAMA transforms as required by the current encoding. */
6378 transform_set_encoding(transform_display *this)
6380 /* Set up the png_modifier '_current' fields then use these to determine how
6381 * to add appropriate chunks.
6383 png_modifier *pm = this->pm;
6385 modifier_set_encoding(pm);
6387 if (modifier_color_encoding_is_set(pm))
6389 if (modifier_color_encoding_is_sRGB(pm))
6390 srgb_modification_init(&this->srgb_mod, pm, PNG_sRGB_INTENT_ABSOLUTE);
6394 /* Set gAMA and cHRM separately. */
6395 gama_modification_init(&this->gama_mod, pm, pm->current_gamma);
6397 if (pm->current_encoding != 0)
6398 chrm_modification_init(&this->chrm_mod, pm, pm->current_encoding);
6403 /* Three functions to end the list: */
6405 image_transform_ini_end(const image_transform *this,
6406 transform_display *that)
6413 image_transform_set_end(const image_transform *this,
6414 transform_display *that, png_structp pp, png_infop pi)
6422 /* At the end of the list recalculate the output image pixel value from the
6423 * double precision values set up by the preceding 'mod' calls:
6426 sample_scale(double sample_value, unsigned int scale)
6428 sample_value = floor(sample_value * scale + .5);
6430 /* Return NaN as 0: */
6431 if (!(sample_value > 0))
6433 else if (sample_value > scale)
6434 sample_value = scale;
6436 return (unsigned int)sample_value;
6440 image_transform_mod_end(const image_transform *this, image_pixel *that,
6441 png_const_structp pp, const transform_display *display)
6443 unsigned int scale = (1U<<that->sample_depth)-1;
6444 int sig_bits = that->sig_bits;
6450 /* At the end recalculate the digitized red green and blue values according
6451 * to the current sample_depth of the pixel.
6453 * The sample value is simply scaled to the maximum, checking for over
6454 * and underflow (which can both happen for some image transforms,
6455 * including simple size scaling, though libpng doesn't do that at present.
6457 that->red = sample_scale(that->redf, scale);
6459 /* This is a bit bogus; really the above calculation should use the red_sBIT
6460 * value, not sample_depth, but because libpng does png_set_shift by just
6461 * shifting the bits we get errors if we don't do it the same way.
6463 if (sig_bits && that->red_sBIT < that->sample_depth)
6464 that->red >>= that->sample_depth - that->red_sBIT;
6466 /* The error value is increased, at the end, according to the lowest sBIT
6467 * value seen. Common sense tells us that the intermediate integer
6468 * representations are no more accurate than +/- 0.5 in the integral values,
6469 * the sBIT allows the implementation to be worse than this. In addition the
6470 * PNG specification actually permits any error within the range (-1..+1),
6471 * but that is ignored here. Instead the final digitized value is compared,
6472 * below to the digitized value of the error limits - this has the net effect
6473 * of allowing (almost) +/-1 in the output value. It's difficult to see how
6474 * any algorithm that digitizes intermediate results can be more accurate.
6476 that->rede += 1./(2*((1U<<that->red_sBIT)-1));
6478 if (that->colour_type & PNG_COLOR_MASK_COLOR)
6480 that->green = sample_scale(that->greenf, scale);
6481 if (sig_bits && that->green_sBIT < that->sample_depth)
6482 that->green >>= that->sample_depth - that->green_sBIT;
6484 that->blue = sample_scale(that->bluef, scale);
6485 if (sig_bits && that->blue_sBIT < that->sample_depth)
6486 that->blue >>= that->sample_depth - that->blue_sBIT;
6488 that->greene += 1./(2*((1U<<that->green_sBIT)-1));
6489 that->bluee += 1./(2*((1U<<that->blue_sBIT)-1));
6493 that->blue = that->green = that->red;
6494 that->bluef = that->greenf = that->redf;
6495 that->bluee = that->greene = that->rede;
6498 if ((that->colour_type & PNG_COLOR_MASK_ALPHA) ||
6499 that->colour_type == PNG_COLOR_TYPE_PALETTE)
6501 that->alpha = sample_scale(that->alphaf, scale);
6502 that->alphae += 1./(2*((1U<<that->alpha_sBIT)-1));
6506 that->alpha = scale; /* opaque */
6507 that->alphaf = 1; /* Override this. */
6508 that->alphae = 0; /* It's exact ;-) */
6511 if (sig_bits && that->alpha_sBIT < that->sample_depth)
6512 that->alpha >>= that->sample_depth - that->alpha_sBIT;
6515 /* Static 'end' structure: */
6516 static image_transform image_transform_end =
6524 image_transform_ini_end,
6525 image_transform_set_end,
6526 image_transform_mod_end,
6527 0 /* never called, I want it to crash if it is! */
6530 /* Reader callbacks and implementations, where they differ from the standard
6534 transform_display_init(transform_display *dp, png_modifier *pm, png_uint_32 id,
6535 const image_transform *transform_list)
6537 memset(dp, 0, sizeof *dp);
6539 /* Standard fields */
6540 standard_display_init(&dp->this, &pm->this, id, do_read_interlace,
6541 pm->use_update_info);
6543 /* Parameter fields */
6545 dp->transform_list = transform_list;
6546 dp->max_gamma_8 = 16;
6548 /* Local variable fields */
6549 dp->output_colour_type = 255; /* invalid */
6550 dp->output_bit_depth = 255; /* invalid */
6551 dp->unpacked = 0; /* not unpacked */
6555 transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
6557 /* Reuse the standard stuff as appropriate. */
6558 standard_info_part1(&dp->this, pp, pi);
6560 /* Now set the list of transforms. */
6561 dp->transform_list->set(dp->transform_list, dp, pp, pi);
6563 /* Update the info structure for these transforms: */
6565 int i = dp->this.use_update_info;
6566 /* Always do one call, even if use_update_info is 0. */
6568 png_read_update_info(pp, pi);
6572 /* And get the output information into the standard_display */
6573 standard_info_part2(&dp->this, pp, pi, 1/*images*/);
6575 /* Plus the extra stuff we need for the transform tests: */
6576 dp->output_colour_type = png_get_color_type(pp, pi);
6577 dp->output_bit_depth = png_get_bit_depth(pp, pi);
6579 /* If png_set_filler is in action then fake the output color type to include
6580 * an alpha channel where appropriate.
6582 if (dp->output_bit_depth >= 8 &&
6583 (dp->output_colour_type == PNG_COLOR_TYPE_RGB ||
6584 dp->output_colour_type == PNG_COLOR_TYPE_GRAY) && dp->this.filler)
6585 dp->output_colour_type |= 4;
6587 /* Validate the combination of colour type and bit depth that we are getting
6588 * out of libpng; the semantics of something not in the PNG spec are, at
6591 switch (dp->output_colour_type)
6593 case PNG_COLOR_TYPE_PALETTE:
6594 if (dp->output_bit_depth > 8) goto error;
6596 case PNG_COLOR_TYPE_GRAY:
6597 if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 ||
6598 dp->output_bit_depth == 4)
6602 if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16)
6610 pos = safecat(message, sizeof message, 0,
6611 "invalid final bit depth: colour type(");
6612 pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
6613 pos = safecat(message, sizeof message, pos, ") with bit depth: ");
6614 pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
6616 png_error(pp, message);
6620 /* Use a test pixel to check that the output agrees with what we expect -
6621 * this avoids running the whole test if the output is unexpected. This also
6622 * checks for internal errors.
6625 image_pixel test_pixel;
6627 memset(&test_pixel, 0, sizeof test_pixel);
6628 test_pixel.colour_type = dp->this.colour_type; /* input */
6629 test_pixel.bit_depth = dp->this.bit_depth;
6630 if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
6631 test_pixel.sample_depth = 8;
6633 test_pixel.sample_depth = test_pixel.bit_depth;
6634 /* Don't need sBIT here, but it must be set to non-zero to avoid
6635 * arithmetic overflows.
6637 test_pixel.have_tRNS = dp->this.is_transparent != 0;
6638 test_pixel.red_sBIT = test_pixel.green_sBIT = test_pixel.blue_sBIT =
6639 test_pixel.alpha_sBIT = test_pixel.sample_depth;
6641 dp->transform_list->mod(dp->transform_list, &test_pixel, pp, dp);
6643 if (test_pixel.colour_type != dp->output_colour_type)
6646 size_t pos = safecat(message, sizeof message, 0, "colour type ");
6648 pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
6649 pos = safecat(message, sizeof message, pos, " expected ");
6650 pos = safecatn(message, sizeof message, pos, test_pixel.colour_type);
6652 png_error(pp, message);
6655 if (test_pixel.bit_depth != dp->output_bit_depth)
6658 size_t pos = safecat(message, sizeof message, 0, "bit depth ");
6660 pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
6661 pos = safecat(message, sizeof message, pos, " expected ");
6662 pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
6664 png_error(pp, message);
6667 /* If both bit depth and colour type are correct check the sample depth.
6669 if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE &&
6670 test_pixel.sample_depth != 8) /* oops - internal error! */
6671 png_error(pp, "pngvalid: internal: palette sample depth not 8");
6672 else if (dp->unpacked && test_pixel.bit_depth != 8)
6673 png_error(pp, "pngvalid: internal: bad unpacked pixel depth");
6674 else if (!dp->unpacked && test_pixel.colour_type != PNG_COLOR_TYPE_PALETTE
6675 && test_pixel.bit_depth != test_pixel.sample_depth)
6678 size_t pos = safecat(message, sizeof message, 0,
6679 "internal: sample depth ");
6681 /* Because unless something has set 'unpacked' or the image is palette
6682 * mapped we expect the transform to keep sample depth and bit depth
6685 pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth);
6686 pos = safecat(message, sizeof message, pos, " expected ");
6687 pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
6689 png_error(pp, message);
6691 else if (test_pixel.bit_depth != dp->output_bit_depth)
6693 /* This could be a libpng error too; libpng has not produced what we
6694 * expect for the output bit depth.
6697 size_t pos = safecat(message, sizeof message, 0,
6698 "internal: bit depth ");
6700 pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
6701 pos = safecat(message, sizeof message, pos, " expected ");
6702 pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
6704 png_error(pp, message);
6709 static void PNGCBAPI
6710 transform_info(png_structp pp, png_infop pi)
6712 transform_info_imp(voidcast(transform_display*, png_get_progressive_ptr(pp)),
6717 transform_range_check(png_const_structp pp, unsigned int r, unsigned int g,
6718 unsigned int b, unsigned int a, unsigned int in_digitized, double in,
6719 unsigned int out, png_byte sample_depth, double err, double limit,
6720 const char *name, double digitization_error)
6722 /* Compare the scaled, digitzed, values of our local calculation (in+-err)
6723 * with the digitized values libpng produced; 'sample_depth' is the actual
6724 * digitization depth of the libpng output colors (the bit depth except for
6725 * palette images where it is always 8.) The check on 'err' is to detect
6726 * internal errors in pngvalid itself.
6728 unsigned int max = (1U<<sample_depth)-1;
6729 double in_min = ceil((in-err)*max - digitization_error);
6730 double in_max = floor((in+err)*max + digitization_error);
6731 if (debugonly(err > limit ||) !(out >= in_min && out <= in_max))
6736 pos = safecat(message, sizeof message, 0, name);
6737 pos = safecat(message, sizeof message, pos, " output value error: rgba(");
6738 pos = safecatn(message, sizeof message, pos, r);
6739 pos = safecat(message, sizeof message, pos, ",");
6740 pos = safecatn(message, sizeof message, pos, g);
6741 pos = safecat(message, sizeof message, pos, ",");
6742 pos = safecatn(message, sizeof message, pos, b);
6743 pos = safecat(message, sizeof message, pos, ",");
6744 pos = safecatn(message, sizeof message, pos, a);
6745 pos = safecat(message, sizeof message, pos, "): ");
6746 pos = safecatn(message, sizeof message, pos, out);
6747 pos = safecat(message, sizeof message, pos, " expected: ");
6748 pos = safecatn(message, sizeof message, pos, in_digitized);
6749 pos = safecat(message, sizeof message, pos, " (");
6750 pos = safecatd(message, sizeof message, pos, (in-err)*max, 3);
6751 pos = safecat(message, sizeof message, pos, "..");
6752 pos = safecatd(message, sizeof message, pos, (in+err)*max, 3);
6753 pos = safecat(message, sizeof message, pos, ")");
6755 png_error(pp, message);
6762 transform_image_validate(transform_display *dp, png_const_structp pp,
6765 /* Constants for the loop below: */
6766 const png_store* const ps = dp->this.ps;
6767 png_byte in_ct = dp->this.colour_type;
6768 png_byte in_bd = dp->this.bit_depth;
6769 png_uint_32 w = dp->this.w;
6770 png_uint_32 h = dp->this.h;
6771 png_byte out_ct = dp->output_colour_type;
6772 png_byte out_bd = dp->output_bit_depth;
6773 png_byte sample_depth =
6774 (png_byte)(out_ct == PNG_COLOR_TYPE_PALETTE ? 8 : out_bd);
6775 png_byte red_sBIT = dp->this.red_sBIT;
6776 png_byte green_sBIT = dp->this.green_sBIT;
6777 png_byte blue_sBIT = dp->this.blue_sBIT;
6778 png_byte alpha_sBIT = dp->this.alpha_sBIT;
6779 int have_tRNS = dp->this.is_transparent;
6780 double digitization_error;
6782 store_palette out_palette;
6787 /* Check for row overwrite errors */
6788 store_image_check(dp->this.ps, pp, 0);
6790 /* Read the palette corresponding to the output if the output colour type
6791 * indicates a palette, otherwise set out_palette to garbage.
6793 if (out_ct == PNG_COLOR_TYPE_PALETTE)
6795 /* Validate that the palette count itself has not changed - this is not
6798 int npalette = (-1);
6800 (void)read_palette(out_palette, &npalette, pp, pi);
6801 if (npalette != dp->this.npalette)
6802 png_error(pp, "unexpected change in palette size");
6804 digitization_error = .5;
6808 png_byte in_sample_depth;
6810 memset(out_palette, 0x5e, sizeof out_palette);
6812 /* use-input-precision means assume that if the input has 8 bit (or less)
6813 * samples and the output has 16 bit samples the calculations will be done
6814 * with 8 bit precision, not 16.
6816 if (in_ct == PNG_COLOR_TYPE_PALETTE || in_bd < 16)
6817 in_sample_depth = 8;
6819 in_sample_depth = in_bd;
6821 if (sample_depth != 16 || in_sample_depth > 8 ||
6822 !dp->pm->calculations_use_input_precision)
6823 digitization_error = .5;
6825 /* Else calculations are at 8 bit precision, and the output actually
6826 * consists of scaled 8-bit values, so scale .5 in 8 bits to the 16 bits:
6829 digitization_error = .5 * 257;
6834 png_const_bytep const pRow = store_image_row(ps, pp, 0, y);
6837 /* The original, standard, row pre-transforms. */
6838 png_byte std[STANDARD_ROWMAX];
6840 transform_row(pp, std, in_ct, in_bd, y);
6842 /* Go through each original pixel transforming it and comparing with what
6843 * libpng did to the same pixel.
6847 image_pixel in_pixel, out_pixel;
6848 unsigned int r, g, b, a;
6850 /* Find out what we think the pixel should be: */
6851 image_pixel_init(&in_pixel, std, in_ct, in_bd, x, dp->this.palette,
6854 in_pixel.red_sBIT = red_sBIT;
6855 in_pixel.green_sBIT = green_sBIT;
6856 in_pixel.blue_sBIT = blue_sBIT;
6857 in_pixel.alpha_sBIT = alpha_sBIT;
6858 in_pixel.have_tRNS = have_tRNS != 0;
6860 /* For error detection, below. */
6866 /* This applies the transforms to the input data, including output
6867 * format operations which must be used when reading the output
6868 * pixel that libpng produces.
6870 dp->transform_list->mod(dp->transform_list, &in_pixel, pp, dp);
6872 /* Read the output pixel and compare it to what we got, we don't
6873 * use the error field here, so no need to update sBIT. in_pixel
6874 * says whether we expect libpng to change the output format.
6876 image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette,
6879 /* We don't expect changes to the index here even if the bit depth is
6882 if (in_ct == PNG_COLOR_TYPE_PALETTE &&
6883 out_ct == PNG_COLOR_TYPE_PALETTE)
6885 if (in_pixel.palette_index != out_pixel.palette_index)
6886 png_error(pp, "unexpected transformed palette index");
6889 /* Check the colours for palette images too - in fact the palette could
6890 * be separately verified itself in most cases.
6892 if (in_pixel.red != out_pixel.red)
6893 transform_range_check(pp, r, g, b, a, in_pixel.red, in_pixel.redf,
6894 out_pixel.red, sample_depth, in_pixel.rede,
6895 dp->pm->limit + 1./(2*((1U<<in_pixel.red_sBIT)-1)), "red/gray",
6896 digitization_error);
6898 if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
6899 in_pixel.green != out_pixel.green)
6900 transform_range_check(pp, r, g, b, a, in_pixel.green,
6901 in_pixel.greenf, out_pixel.green, sample_depth, in_pixel.greene,
6902 dp->pm->limit + 1./(2*((1U<<in_pixel.green_sBIT)-1)), "green",
6903 digitization_error);
6905 if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
6906 in_pixel.blue != out_pixel.blue)
6907 transform_range_check(pp, r, g, b, a, in_pixel.blue, in_pixel.bluef,
6908 out_pixel.blue, sample_depth, in_pixel.bluee,
6909 dp->pm->limit + 1./(2*((1U<<in_pixel.blue_sBIT)-1)), "blue",
6910 digitization_error);
6912 if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0 &&
6913 in_pixel.alpha != out_pixel.alpha)
6914 transform_range_check(pp, r, g, b, a, in_pixel.alpha,
6915 in_pixel.alphaf, out_pixel.alpha, sample_depth, in_pixel.alphae,
6916 dp->pm->limit + 1./(2*((1U<<in_pixel.alpha_sBIT)-1)), "alpha",
6917 digitization_error);
6918 } /* pixel (x) loop */
6919 } /* row (y) loop */
6921 /* Record that something was actually checked to avoid a false positive. */
6922 dp->this.ps->validated = 1;
6925 static void PNGCBAPI
6926 transform_end(png_structp ppIn, png_infop pi)
6928 png_const_structp pp = ppIn;
6929 transform_display *dp = voidcast(transform_display*,
6930 png_get_progressive_ptr(pp));
6932 if (!dp->this.speed)
6933 transform_image_validate(dp, pp, pi);
6935 dp->this.ps->validated = 1;
6938 /* A single test run. */
6940 transform_test(png_modifier *pmIn, png_uint_32 idIn,
6941 const image_transform* transform_listIn, const char * const name)
6943 transform_display d;
6944 context(&pmIn->this, fault);
6946 transform_display_init(&d, pmIn, idIn, transform_listIn);
6953 char full_name[256];
6955 /* Make sure the encoding fields are correct and enter the required
6958 transform_set_encoding(&d);
6960 /* Add any modifications required by the transform list. */
6961 d.transform_list->ini(d.transform_list, &d);
6963 /* Add the color space information, if any, to the name. */
6964 pos = safecat(full_name, sizeof full_name, pos, name);
6965 pos = safecat_current_encoding(full_name, sizeof full_name, pos, d.pm);
6967 /* Get a png_struct for reading the image. */
6968 pp = set_modifier_for_read(d.pm, &pi, d.this.id, full_name);
6969 standard_palette_init(&d.this);
6972 /* Logging (debugging only) */
6976 (void)store_message(&d.pm->this, pp, buffer, sizeof buffer, 0,
6979 fprintf(stderr, "%s\n", buffer);
6983 /* Introduce the correct read function. */
6984 if (d.pm->this.progressive)
6986 /* Share the row function with the standard implementation. */
6987 png_set_progressive_read_fn(pp, &d, transform_info, progressive_row,
6990 /* Now feed data into the reader until we reach the end: */
6991 modifier_progressive_read(d.pm, pp, pi);
6995 /* modifier_read expects a png_modifier* */
6996 png_set_read_fn(pp, d.pm, modifier_read);
6998 /* Check the header values: */
6999 png_read_info(pp, pi);
7001 /* Process the 'info' requirements. Only one image is generated */
7002 transform_info_imp(&d, pp, pi);
7004 sequential_row(&d.this, pp, pi, -1, 0);
7007 transform_image_validate(&d, pp, pi);
7009 d.this.ps->validated = 1;
7012 modifier_reset(d.pm);
7017 modifier_reset(voidcast(png_modifier*,(void*)fault));
7021 /* The transforms: */
7022 #define ITSTRUCT(name) image_transform_##name
7023 #define ITDATA(name) image_transform_data_##name
7024 #define image_transform_ini image_transform_default_ini
7026 static image_transform ITSTRUCT(name) =\
7034 image_transform_ini,\
7035 image_transform_png_set_##name##_set,\
7036 image_transform_png_set_##name##_mod,\
7037 image_transform_png_set_##name##_add\
7039 #define PT ITSTRUCT(end) /* stores the previous transform */
7042 extern void image_transform_default_ini(const image_transform *this,
7043 transform_display *that); /* silence GCC warnings */
7045 void /* private, but almost always needed */
7046 image_transform_default_ini(const image_transform *this,
7047 transform_display *that)
7049 this->next->ini(this->next, that);
7052 #ifdef PNG_READ_BACKGROUND_SUPPORTED
7054 image_transform_default_add(image_transform *this,
7055 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7067 #ifdef PNG_READ_EXPAND_SUPPORTED
7068 /* png_set_palette_to_rgb */
7070 image_transform_png_set_palette_to_rgb_set(const image_transform *this,
7071 transform_display *that, png_structp pp, png_infop pi)
7073 png_set_palette_to_rgb(pp);
7074 this->next->set(this->next, that, pp, pi);
7078 image_transform_png_set_palette_to_rgb_mod(const image_transform *this,
7079 image_pixel *that, png_const_structp pp,
7080 const transform_display *display)
7082 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7083 image_pixel_convert_PLTE(that);
7085 this->next->mod(this->next, that, pp, display);
7089 image_transform_png_set_palette_to_rgb_add(image_transform *this,
7090 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7097 return colour_type == PNG_COLOR_TYPE_PALETTE;
7102 #define PT ITSTRUCT(palette_to_rgb)
7103 #endif /* PNG_READ_EXPAND_SUPPORTED */
7105 #ifdef PNG_READ_EXPAND_SUPPORTED
7106 /* png_set_tRNS_to_alpha */
7108 image_transform_png_set_tRNS_to_alpha_set(const image_transform *this,
7109 transform_display *that, png_structp pp, png_infop pi)
7111 png_set_tRNS_to_alpha(pp);
7113 /* If there was a tRNS chunk that would get expanded and add an alpha
7114 * channel is_transparent must be updated:
7116 if (that->this.has_tRNS)
7117 that->this.is_transparent = 1;
7119 this->next->set(this->next, that, pp, pi);
7123 image_transform_png_set_tRNS_to_alpha_mod(const image_transform *this,
7124 image_pixel *that, png_const_structp pp,
7125 const transform_display *display)
7127 #if PNG_LIBPNG_VER < 10700
7128 /* LIBPNG BUG: this always forces palette images to RGB. */
7129 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7130 image_pixel_convert_PLTE(that);
7133 /* This effectively does an 'expand' only if there is some transparency to
7134 * convert to an alpha channel.
7136 if (that->have_tRNS)
7137 # if PNG_LIBPNG_VER >= 10700
7138 if (that->colour_type != PNG_COLOR_TYPE_PALETTE &&
7139 (that->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
7141 image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
7143 #if PNG_LIBPNG_VER < 10700
7144 /* LIBPNG BUG: otherwise libpng still expands to 8 bits! */
7147 if (that->bit_depth < 8)
7149 if (that->sample_depth < 8)
7150 that->sample_depth = 8;
7154 this->next->mod(this->next, that, pp, display);
7158 image_transform_png_set_tRNS_to_alpha_add(image_transform *this,
7159 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7166 /* We don't know yet whether there will be a tRNS chunk, but we know that
7167 * this transformation should do nothing if there already is an alpha
7168 * channel. In addition, after the bug fix in 1.7.0, there is no longer
7169 * any action on a palette image.
7172 # if PNG_LIBPNG_VER >= 10700
7173 colour_type != PNG_COLOR_TYPE_PALETTE &&
7175 (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
7180 #define PT ITSTRUCT(tRNS_to_alpha)
7181 #endif /* PNG_READ_EXPAND_SUPPORTED */
7183 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
7184 /* png_set_gray_to_rgb */
7186 image_transform_png_set_gray_to_rgb_set(const image_transform *this,
7187 transform_display *that, png_structp pp, png_infop pi)
7189 png_set_gray_to_rgb(pp);
7190 /* NOTE: this doesn't result in tRNS expansion. */
7191 this->next->set(this->next, that, pp, pi);
7195 image_transform_png_set_gray_to_rgb_mod(const image_transform *this,
7196 image_pixel *that, png_const_structp pp,
7197 const transform_display *display)
7199 /* NOTE: we can actually pend the tRNS processing at this point because we
7200 * can correctly recognize the original pixel value even though we have
7201 * mapped the one gray channel to the three RGB ones, but in fact libpng
7202 * doesn't do this, so we don't either.
7204 if ((that->colour_type & PNG_COLOR_MASK_COLOR) == 0 && that->have_tRNS)
7205 image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
7207 /* Simply expand the bit depth and alter the colour type as required. */
7208 if (that->colour_type == PNG_COLOR_TYPE_GRAY)
7210 /* RGB images have a bit depth at least equal to '8' */
7211 if (that->bit_depth < 8)
7212 that->sample_depth = that->bit_depth = 8;
7214 /* And just changing the colour type works here because the green and blue
7215 * channels are being maintained in lock-step with the red/gray:
7217 that->colour_type = PNG_COLOR_TYPE_RGB;
7220 else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
7221 that->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
7223 this->next->mod(this->next, that, pp, display);
7227 image_transform_png_set_gray_to_rgb_add(image_transform *this,
7228 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7235 return (colour_type & PNG_COLOR_MASK_COLOR) == 0;
7240 #define PT ITSTRUCT(gray_to_rgb)
7241 #endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */
7243 #ifdef PNG_READ_EXPAND_SUPPORTED
7244 /* png_set_expand */
7246 image_transform_png_set_expand_set(const image_transform *this,
7247 transform_display *that, png_structp pp, png_infop pi)
7251 if (that->this.has_tRNS)
7252 that->this.is_transparent = 1;
7254 this->next->set(this->next, that, pp, pi);
7258 image_transform_png_set_expand_mod(const image_transform *this,
7259 image_pixel *that, png_const_structp pp,
7260 const transform_display *display)
7262 /* The general expand case depends on what the colour type is: */
7263 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7264 image_pixel_convert_PLTE(that);
7265 else if (that->bit_depth < 8) /* grayscale */
7266 that->sample_depth = that->bit_depth = 8;
7268 if (that->have_tRNS)
7269 image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
7271 this->next->mod(this->next, that, pp, display);
7275 image_transform_png_set_expand_add(image_transform *this,
7276 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7283 /* 'expand' should do nothing for RGBA or GA input - no tRNS and the bit
7284 * depth is at least 8 already.
7286 return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
7291 #define PT ITSTRUCT(expand)
7292 #endif /* PNG_READ_EXPAND_SUPPORTED */
7294 #ifdef PNG_READ_EXPAND_SUPPORTED
7295 /* png_set_expand_gray_1_2_4_to_8
7296 * Pre 1.7.0 LIBPNG BUG: this just does an 'expand'
7299 image_transform_png_set_expand_gray_1_2_4_to_8_set(
7300 const image_transform *this, transform_display *that, png_structp pp,
7303 png_set_expand_gray_1_2_4_to_8(pp);
7304 /* NOTE: don't expect this to expand tRNS */
7305 this->next->set(this->next, that, pp, pi);
7309 image_transform_png_set_expand_gray_1_2_4_to_8_mod(
7310 const image_transform *this, image_pixel *that, png_const_structp pp,
7311 const transform_display *display)
7313 #if PNG_LIBPNG_VER < 10700
7314 image_transform_png_set_expand_mod(this, that, pp, display);
7316 /* Only expand grayscale of bit depth less than 8: */
7317 if (that->colour_type == PNG_COLOR_TYPE_GRAY &&
7318 that->bit_depth < 8)
7319 that->sample_depth = that->bit_depth = 8;
7321 this->next->mod(this->next, that, pp, display);
7322 #endif /* 1.7 or later */
7326 image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this,
7327 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7329 #if PNG_LIBPNG_VER < 10700
7330 return image_transform_png_set_expand_add(this, that, colour_type,
7338 /* This should do nothing unless the color type is gray and the bit depth is
7341 return colour_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8;
7342 #endif /* 1.7 or later */
7345 IT(expand_gray_1_2_4_to_8);
7347 #define PT ITSTRUCT(expand_gray_1_2_4_to_8)
7348 #endif /* PNG_READ_EXPAND_SUPPORTED */
7350 #ifdef PNG_READ_EXPAND_16_SUPPORTED
7351 /* png_set_expand_16 */
7353 image_transform_png_set_expand_16_set(const image_transform *this,
7354 transform_display *that, png_structp pp, png_infop pi)
7356 png_set_expand_16(pp);
7358 /* NOTE: prior to 1.7 libpng does SET_EXPAND as well, so tRNS is expanded. */
7359 # if PNG_LIBPNG_VER < 10700
7360 if (that->this.has_tRNS)
7361 that->this.is_transparent = 1;
7364 this->next->set(this->next, that, pp, pi);
7368 image_transform_png_set_expand_16_mod(const image_transform *this,
7369 image_pixel *that, png_const_structp pp,
7370 const transform_display *display)
7372 /* Expect expand_16 to expand everything to 16 bits as a result of also
7373 * causing 'expand' to happen.
7375 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7376 image_pixel_convert_PLTE(that);
7378 if (that->have_tRNS)
7379 image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
7381 if (that->bit_depth < 16)
7382 that->sample_depth = that->bit_depth = 16;
7384 this->next->mod(this->next, that, pp, display);
7388 image_transform_png_set_expand_16_add(image_transform *this,
7389 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7396 /* expand_16 does something unless the bit depth is already 16. */
7397 return bit_depth < 16;
7402 #define PT ITSTRUCT(expand_16)
7403 #endif /* PNG_READ_EXPAND_16_SUPPORTED */
7405 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED /* API added in 1.5.4 */
7406 /* png_set_scale_16 */
7408 image_transform_png_set_scale_16_set(const image_transform *this,
7409 transform_display *that, png_structp pp, png_infop pi)
7411 png_set_scale_16(pp);
7412 # if PNG_LIBPNG_VER < 10700
7413 /* libpng will limit the gamma table size: */
7414 that->max_gamma_8 = PNG_MAX_GAMMA_8;
7416 this->next->set(this->next, that, pp, pi);
7420 image_transform_png_set_scale_16_mod(const image_transform *this,
7421 image_pixel *that, png_const_structp pp,
7422 const transform_display *display)
7424 if (that->bit_depth == 16)
7426 that->sample_depth = that->bit_depth = 8;
7427 if (that->red_sBIT > 8) that->red_sBIT = 8;
7428 if (that->green_sBIT > 8) that->green_sBIT = 8;
7429 if (that->blue_sBIT > 8) that->blue_sBIT = 8;
7430 if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
7433 this->next->mod(this->next, that, pp, display);
7437 image_transform_png_set_scale_16_add(image_transform *this,
7438 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7445 return bit_depth > 8;
7450 #define PT ITSTRUCT(scale_16)
7451 #endif /* PNG_READ_SCALE_16_TO_8_SUPPORTED (1.5.4 on) */
7453 #ifdef PNG_READ_16_TO_8_SUPPORTED /* the default before 1.5.4 */
7454 /* png_set_strip_16 */
7456 image_transform_png_set_strip_16_set(const image_transform *this,
7457 transform_display *that, png_structp pp, png_infop pi)
7459 png_set_strip_16(pp);
7460 # if PNG_LIBPNG_VER < 10700
7461 /* libpng will limit the gamma table size: */
7462 that->max_gamma_8 = PNG_MAX_GAMMA_8;
7464 this->next->set(this->next, that, pp, pi);
7468 image_transform_png_set_strip_16_mod(const image_transform *this,
7469 image_pixel *that, png_const_structp pp,
7470 const transform_display *display)
7472 if (that->bit_depth == 16)
7474 that->sample_depth = that->bit_depth = 8;
7475 if (that->red_sBIT > 8) that->red_sBIT = 8;
7476 if (that->green_sBIT > 8) that->green_sBIT = 8;
7477 if (that->blue_sBIT > 8) that->blue_sBIT = 8;
7478 if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
7480 /* Prior to 1.5.4 png_set_strip_16 would use an 'accurate' method if this
7481 * configuration option is set. From 1.5.4 the flag is never set and the
7482 * 'scale' API (above) must be used.
7484 # ifdef PNG_READ_ACCURATE_SCALE_SUPPORTED
7485 # if PNG_LIBPNG_VER >= 10504
7486 # error PNG_READ_ACCURATE_SCALE should not be set
7489 /* The strip 16 algorithm drops the low 8 bits rather than calculating
7490 * 1/257, so we need to adjust the permitted errors appropriately:
7491 * Notice that this is only relevant prior to the addition of the
7492 * png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
7495 const double d = (255-128.5)/65535;
7504 this->next->mod(this->next, that, pp, display);
7508 image_transform_png_set_strip_16_add(image_transform *this,
7509 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7516 return bit_depth > 8;
7521 #define PT ITSTRUCT(strip_16)
7522 #endif /* PNG_READ_16_TO_8_SUPPORTED */
7524 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
7525 /* png_set_strip_alpha */
7527 image_transform_png_set_strip_alpha_set(const image_transform *this,
7528 transform_display *that, png_structp pp, png_infop pi)
7530 png_set_strip_alpha(pp);
7531 this->next->set(this->next, that, pp, pi);
7535 image_transform_png_set_strip_alpha_mod(const image_transform *this,
7536 image_pixel *that, png_const_structp pp,
7537 const transform_display *display)
7539 if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
7540 that->colour_type = PNG_COLOR_TYPE_GRAY;
7541 else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
7542 that->colour_type = PNG_COLOR_TYPE_RGB;
7544 that->have_tRNS = 0;
7547 this->next->mod(this->next, that, pp, display);
7551 image_transform_png_set_strip_alpha_add(image_transform *this,
7552 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7559 return (colour_type & PNG_COLOR_MASK_ALPHA) != 0;
7564 #define PT ITSTRUCT(strip_alpha)
7565 #endif /* PNG_READ_STRIP_ALPHA_SUPPORTED */
7567 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
7568 /* png_set_rgb_to_gray(png_structp, int err_action, double red, double green)
7569 * png_set_rgb_to_gray_fixed(png_structp, int err_action, png_fixed_point red,
7570 * png_fixed_point green)
7571 * png_get_rgb_to_gray_status
7573 * The 'default' test here uses values known to be used inside libpng prior to
7580 * These values are being retained for compatibility, along with the somewhat
7581 * broken truncation calculation in the fast-and-inaccurate code path. Older
7582 * versions of libpng will fail the accuracy tests below because they use the
7583 * truncation algorithm everywhere.
7585 #define data ITDATA(rgb_to_gray)
7588 double gamma; /* File gamma to use in processing */
7590 /* The following are the parameters for png_set_rgb_to_gray: */
7591 # ifdef PNG_FLOATING_POINT_SUPPORTED
7593 double green_to_set;
7595 png_fixed_point red_to_set;
7596 png_fixed_point green_to_set;
7599 /* The actual coefficients: */
7600 double red_coefficient;
7601 double green_coefficient;
7602 double blue_coefficient;
7604 /* Set if the coeefficients have been overridden. */
7605 int coefficients_overridden;
7608 #undef image_transform_ini
7609 #define image_transform_ini image_transform_png_set_rgb_to_gray_ini
7611 image_transform_png_set_rgb_to_gray_ini(const image_transform *this,
7612 transform_display *that)
7614 png_modifier *pm = that->pm;
7615 const color_encoding *e = pm->current_encoding;
7619 /* Since we check the encoding this flag must be set: */
7620 pm->test_uses_encoding = 1;
7622 /* If 'e' is not NULL chromaticity information is present and either a cHRM
7623 * or an sRGB chunk will be inserted.
7627 /* Coefficients come from the encoding, but may need to be normalized to a
7628 * white point Y of 1.0
7630 const double whiteY = e->red.Y + e->green.Y + e->blue.Y;
7632 data.red_coefficient = e->red.Y;
7633 data.green_coefficient = e->green.Y;
7634 data.blue_coefficient = e->blue.Y;
7638 data.red_coefficient /= whiteY;
7639 data.green_coefficient /= whiteY;
7640 data.blue_coefficient /= whiteY;
7646 /* The default (built in) coefficients, as above: */
7647 # if PNG_LIBPNG_VER < 10700
7648 data.red_coefficient = 6968 / 32768.;
7649 data.green_coefficient = 23434 / 32768.;
7650 data.blue_coefficient = 2366 / 32768.;
7652 data.red_coefficient = .2126;
7653 data.green_coefficient = .7152;
7654 data.blue_coefficient = .0722;
7658 data.gamma = pm->current_gamma;
7660 /* If not set then the calculations assume linear encoding (implicitly): */
7661 if (data.gamma == 0)
7664 /* The arguments to png_set_rgb_to_gray can override the coefficients implied
7665 * by the color space encoding. If doing exhaustive checks do the override
7666 * in each case, otherwise do it randomly.
7668 if (pm->test_exhaustive)
7670 /* First time in coefficients_overridden is 0, the following sets it to 1,
7671 * so repeat if it is set. If a test fails this may mean we subsequently
7672 * skip a non-override test, ignore that.
7674 data.coefficients_overridden = !data.coefficients_overridden;
7675 pm->repeat = data.coefficients_overridden != 0;
7679 data.coefficients_overridden = random_choice();
7681 if (data.coefficients_overridden)
7683 /* These values override the color encoding defaults, simply use random
7690 data.green_coefficient = total = (ru & 0xffff) / 65535.;
7692 data.red_coefficient = (1 - total) * (ru & 0xffff) / 65535.;
7693 total += data.red_coefficient;
7694 data.blue_coefficient = 1 - total;
7696 # ifdef PNG_FLOATING_POINT_SUPPORTED
7697 data.red_to_set = data.red_coefficient;
7698 data.green_to_set = data.green_coefficient;
7700 data.red_to_set = fix(data.red_coefficient);
7701 data.green_to_set = fix(data.green_coefficient);
7704 /* The following just changes the error messages: */
7705 pm->encoding_ignored = 1;
7710 data.red_to_set = -1;
7711 data.green_to_set = -1;
7714 /* Adjust the error limit in the png_modifier because of the larger errors
7715 * produced in the digitization during the gamma handling.
7717 if (data.gamma != 1) /* Use gamma tables */
7719 if (that->this.bit_depth == 16 || pm->assume_16_bit_calculations)
7721 /* The computations have the form:
7723 * r * rc + g * gc + b * bc
7725 * Each component of which is +/-1/65535 from the gamma_to_1 table
7726 * lookup, resulting in a base error of +/-6. The gamma_from_1
7727 * conversion adds another +/-2 in the 16-bit case and
7728 * +/-(1<<(15-PNG_MAX_GAMMA_8)) in the 8-bit case.
7730 # if PNG_LIBPNG_VER < 10700
7731 if (that->this.bit_depth < 16)
7732 that->max_gamma_8 = PNG_MAX_GAMMA_8;
7734 that->pm->limit += pow(
7735 (that->this.bit_depth == 16 || that->max_gamma_8 > 14 ?
7737 6. + (1<<(15-that->max_gamma_8))
7738 )/65535, data.gamma);
7743 /* Rounding to 8 bits in the linear space causes massive errors which
7744 * will trigger the error check in transform_range_check. Fix that
7745 * here by taking the gamma encoding into account.
7747 * When DIGITIZE is set because a pre-1.7 version of libpng is being
7748 * tested allow a bigger slack.
7750 * NOTE: this number only affects the internal limit check in pngvalid,
7751 * it has no effect on the limits applied to the libpng values.
7754 that->pm->limit += pow( 2.0/255, data.gamma);
7756 that->pm->limit += pow( 1.0/255, data.gamma);
7763 /* With no gamma correction a large error comes from the truncation of the
7764 * calculation in the 8 bit case, allow for that here.
7766 if (that->this.bit_depth != 16 && !pm->assume_16_bit_calculations)
7767 that->pm->limit += 4E-3;
7772 image_transform_png_set_rgb_to_gray_set(const image_transform *this,
7773 transform_display *that, png_structp pp, png_infop pi)
7775 int error_action = 1; /* no error, no defines in png.h */
7777 # ifdef PNG_FLOATING_POINT_SUPPORTED
7778 png_set_rgb_to_gray(pp, error_action, data.red_to_set, data.green_to_set);
7780 png_set_rgb_to_gray_fixed(pp, error_action, data.red_to_set,
7784 # ifdef PNG_READ_cHRM_SUPPORTED
7785 if (that->pm->current_encoding != 0)
7787 /* We have an encoding so a cHRM chunk may have been set; if so then
7788 * check that the libpng APIs give the correct (X,Y,Z) values within
7789 * some margin of error for the round trip through the chromaticity
7792 # ifdef PNG_FLOATING_POINT_SUPPORTED
7793 # define API_function png_get_cHRM_XYZ
7794 # define API_form "FP"
7795 # define API_type double
7796 # define API_cvt(x) (x)
7798 # define API_function png_get_cHRM_XYZ_fixed
7799 # define API_form "fixed"
7800 # define API_type png_fixed_point
7801 # define API_cvt(x) ((double)(x)/PNG_FP_1)
7804 API_type rX, gX, bX;
7805 API_type rY, gY, bY;
7806 API_type rZ, gZ, bZ;
7808 if ((API_function(pp, pi, &rX, &rY, &rZ, &gX, &gY, &gZ, &bX, &bY, &bZ)
7809 & PNG_INFO_cHRM) != 0)
7813 color_encoding e, o;
7815 /* Expect libpng to return a normalized result, but the original
7816 * color space encoding may not be normalized.
7818 modifier_current_encoding(that->pm, &o);
7819 normalize_color_encoding(&o);
7821 /* Sanity check the pngvalid code - the coefficients should match
7822 * the normalized Y values of the encoding unless they were
7825 if (data.red_to_set == -1 && data.green_to_set == -1 &&
7826 (fabs(o.red.Y - data.red_coefficient) > DBL_EPSILON ||
7827 fabs(o.green.Y - data.green_coefficient) > DBL_EPSILON ||
7828 fabs(o.blue.Y - data.blue_coefficient) > DBL_EPSILON))
7829 png_error(pp, "internal pngvalid cHRM coefficient error");
7831 /* Generate a colour space encoding. */
7832 e.gamma = o.gamma; /* not used */
7833 e.red.X = API_cvt(rX);
7834 e.red.Y = API_cvt(rY);
7835 e.red.Z = API_cvt(rZ);
7836 e.green.X = API_cvt(gX);
7837 e.green.Y = API_cvt(gY);
7838 e.green.Z = API_cvt(gZ);
7839 e.blue.X = API_cvt(bX);
7840 e.blue.Y = API_cvt(bY);
7841 e.blue.Z = API_cvt(bZ);
7843 /* This should match the original one from the png_modifier, within
7844 * the range permitted by the libpng fixed point representation.
7847 el = "-"; /* Set to element name with error */
7849 # define CHECK(col,x)\
7851 double err = fabs(o.col.x - e.col.x);\
7855 el = #col "(" #x ")";\
7869 /* Here in both fixed and floating cases to check the values read
7870 * from the cHRm chunk. PNG uses fixed point in the cHRM chunk, so
7871 * we can't expect better than +/-.5E-5 on the result, allow 1E-5.
7878 pos = safecat(buffer, sizeof buffer, pos, API_form);
7879 pos = safecat(buffer, sizeof buffer, pos, " cHRM ");
7880 pos = safecat(buffer, sizeof buffer, pos, el);
7881 pos = safecat(buffer, sizeof buffer, pos, " error: ");
7882 pos = safecatd(buffer, sizeof buffer, pos, maxe, 7);
7883 pos = safecat(buffer, sizeof buffer, pos, " ");
7884 /* Print the color space without the gamma value: */
7885 pos = safecat_color_encoding(buffer, sizeof buffer, pos, &o, 0);
7886 pos = safecat(buffer, sizeof buffer, pos, " -> ");
7887 pos = safecat_color_encoding(buffer, sizeof buffer, pos, &e, 0);
7889 png_error(pp, buffer);
7893 # endif /* READ_cHRM */
7895 this->next->set(this->next, that, pp, pi);
7899 image_transform_png_set_rgb_to_gray_mod(const image_transform *this,
7900 image_pixel *that, png_const_structp pp,
7901 const transform_display *display)
7903 if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0)
7907 # if PNG_LIBPNG_VER < 10700
7908 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7909 image_pixel_convert_PLTE(that);
7912 /* Image now has RGB channels... */
7915 png_modifier *pm = display->pm;
7916 unsigned int sample_depth = that->sample_depth;
7917 unsigned int calc_depth = (pm->assume_16_bit_calculations ? 16 :
7919 unsigned int gamma_depth =
7920 (sample_depth == 16 ?
7921 display->max_gamma_8 :
7922 (pm->assume_16_bit_calculations ?
7923 display->max_gamma_8 :
7927 double rlo, rhi, glo, ghi, blo, bhi, graylo, grayhi;
7929 /* Do this using interval arithmetic, otherwise it is too difficult to
7930 * handle the errors correctly.
7932 * To handle the gamma correction work out the upper and lower bounds
7933 * of the digitized value. Assume rounding here - normally the values
7934 * will be identical after this operation if there is only one
7935 * transform, feel free to delete the png_error checks on this below in
7936 * the future (this is just me trying to ensure it works!)
7938 * Interval arithmetic is exact, but to implement it it must be
7939 * possible to control the floating point implementation rounding mode.
7940 * This cannot be done in ANSI-C, so instead I reduce the 'lo' values
7941 * by DBL_EPSILON and increase the 'hi' values by the same.
7943 # define DD(v,d,r) (digitize(v*(1-DBL_EPSILON), d, r) * (1-DBL_EPSILON))
7944 # define DU(v,d,r) (digitize(v*(1+DBL_EPSILON), d, r) * (1+DBL_EPSILON))
7946 r = rlo = rhi = that->redf;
7948 rlo = DD(rlo, calc_depth, 1/*round*/);
7950 rhi = DU(rhi, calc_depth, 1/*round*/);
7952 g = glo = ghi = that->greenf;
7953 glo -= that->greene;
7954 glo = DD(glo, calc_depth, 1/*round*/);
7955 ghi += that->greene;
7956 ghi = DU(ghi, calc_depth, 1/*round*/);
7958 b = blo = bhi = that->bluef;
7960 blo = DD(blo, calc_depth, 1/*round*/);
7962 bhi = DU(bhi, calc_depth, 1/*round*/);
7964 isgray = r==g && g==b;
7966 if (data.gamma != 1)
7968 const double power = 1/data.gamma;
7969 const double abse = .5/(sample_depth == 16 ? 65535 : 255);
7971 /* If a gamma calculation is done it is done using lookup tables of
7972 * precision gamma_depth, so the already digitized value above may
7973 * need to be further digitized here.
7975 if (gamma_depth != calc_depth)
7977 rlo = DD(rlo, gamma_depth, 0/*truncate*/);
7978 rhi = DU(rhi, gamma_depth, 0/*truncate*/);
7979 glo = DD(glo, gamma_depth, 0/*truncate*/);
7980 ghi = DU(ghi, gamma_depth, 0/*truncate*/);
7981 blo = DD(blo, gamma_depth, 0/*truncate*/);
7982 bhi = DU(bhi, gamma_depth, 0/*truncate*/);
7985 /* 'abse' is the error in the gamma table calculation itself. */
7987 rlo = DD(pow(rlo, power)-abse, calc_depth, 1);
7988 rhi = DU(pow(rhi, power)+abse, calc_depth, 1);
7991 glo = DD(pow(glo, power)-abse, calc_depth, 1);
7992 ghi = DU(pow(ghi, power)+abse, calc_depth, 1);
7995 blo = DD(pow(blo, power)-abse, calc_depth, 1);
7996 bhi = DU(pow(bhi, power)+abse, calc_depth, 1);
7999 /* Now calculate the actual gray values. Although the error in the
8000 * coefficients depends on whether they were specified on the command
8001 * line (in which case truncation to 15 bits happened) or not (rounding
8002 * was used) the maximum error in an individual coefficient is always
8003 * 2/32768, because even in the rounding case the requirement that
8004 * coefficients add up to 32768 can cause a larger rounding error.
8006 * The only time when rounding doesn't occur in 1.5.5 and later is when
8007 * the non-gamma code path is used for less than 16 bit data.
8009 gray = r * data.red_coefficient + g * data.green_coefficient +
8010 b * data.blue_coefficient;
8013 int do_round = data.gamma != 1 || calc_depth == 16;
8014 const double ce = 2. / 32768;
8016 graylo = DD(rlo * (data.red_coefficient-ce) +
8017 glo * (data.green_coefficient-ce) +
8018 blo * (data.blue_coefficient-ce), calc_depth, do_round);
8019 if (graylo > gray) /* always accept the right answer */
8022 grayhi = DU(rhi * (data.red_coefficient+ce) +
8023 ghi * (data.green_coefficient+ce) +
8024 bhi * (data.blue_coefficient+ce), calc_depth, do_round);
8029 /* And invert the gamma. */
8030 if (data.gamma != 1)
8032 const double power = data.gamma;
8034 /* And this happens yet again, shifting the values once more. */
8035 if (gamma_depth != sample_depth)
8037 rlo = DD(rlo, gamma_depth, 0/*truncate*/);
8038 rhi = DU(rhi, gamma_depth, 0/*truncate*/);
8039 glo = DD(glo, gamma_depth, 0/*truncate*/);
8040 ghi = DU(ghi, gamma_depth, 0/*truncate*/);
8041 blo = DD(blo, gamma_depth, 0/*truncate*/);
8042 bhi = DU(bhi, gamma_depth, 0/*truncate*/);
8045 gray = pow(gray, power);
8046 graylo = DD(pow(graylo, power), sample_depth, 1);
8047 grayhi = DU(pow(grayhi, power), sample_depth, 1);
8053 /* Now the error can be calculated.
8055 * If r==g==b because there is no overall gamma correction libpng
8056 * currently preserves the original value.
8059 err = (that->rede + that->greene + that->bluee)/3;
8063 err = fabs(grayhi-gray);
8065 if (fabs(gray - graylo) > err)
8066 err = fabs(graylo-gray);
8069 /* Check that this worked: */
8070 if (err > pm->limit)
8075 pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
8076 pos = safecatd(buffer, sizeof buffer, pos, err, 6);
8077 pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
8078 pos = safecatd(buffer, sizeof buffer, pos, pm->limit, 6);
8079 png_warning(pp, buffer);
8082 #endif /* !RELEASE_BUILD */
8085 # else /* !DIGITIZE */
8087 double r = that->redf;
8088 double re = that->rede;
8089 double g = that->greenf;
8090 double ge = that->greene;
8091 double b = that->bluef;
8092 double be = that->bluee;
8094 # if PNG_LIBPNG_VER < 10700
8095 /* The true gray case involves no math in earlier versions (not
8096 * true, there was some if gamma correction was happening too.)
8098 if (r == g && r == b)
8102 if (err < ge) err = ge;
8103 if (err < be) err = be;
8107 # endif /* before 1.7 */
8108 if (data.gamma == 1)
8110 /* There is no need to do the conversions to and from linear space,
8111 * so the calculation should be a lot more accurate. There is a
8112 * built in error in the coefficients because they only have 15 bits
8113 * and are adjusted to make sure they add up to 32768. This
8114 * involves a integer calculation with truncation of the form:
8116 * ((int)(coefficient * 100000) * 32768)/100000
8118 * This is done to the red and green coefficients (the ones
8119 * provided to the API) then blue is calculated from them so the
8120 * result adds up to 32768. In the worst case this can result in
8121 * a -1 error in red and green and a +2 error in blue. Consequently
8122 * the worst case in the calculation below is 2/32768 error.
8124 * TODO: consider fixing this in libpng by rounding the calculation
8125 * limiting the error to 1/32768.
8127 * Handling this by adding 2/32768 here avoids needing to increase
8128 * the global error limits to take this into account.)
8130 gray = r * data.red_coefficient + g * data.green_coefficient +
8131 b * data.blue_coefficient;
8132 err = re * data.red_coefficient + ge * data.green_coefficient +
8133 be * data.blue_coefficient + 2./32768 + gray * 5 * DBL_EPSILON;
8138 /* The calculation happens in linear space, and this produces much
8139 * wider errors in the encoded space. These are handled here by
8140 * factoring the errors in to the calculation. There are two table
8141 * lookups in the calculation and each introduces a quantization
8142 * error defined by the table size.
8144 png_modifier *pm = display->pm;
8145 double in_qe = (that->sample_depth > 8 ? .5/65535 : .5/255);
8146 double out_qe = (that->sample_depth > 8 ? .5/65535 :
8147 (pm->assume_16_bit_calculations ? .5/(1<<display->max_gamma_8) :
8149 double rhi, ghi, bhi, grayhi;
8150 double g1 = 1/data.gamma;
8152 rhi = r + re + in_qe; if (rhi > 1) rhi = 1;
8153 r -= re + in_qe; if (r < 0) r = 0;
8154 ghi = g + ge + in_qe; if (ghi > 1) ghi = 1;
8155 g -= ge + in_qe; if (g < 0) g = 0;
8156 bhi = b + be + in_qe; if (bhi > 1) bhi = 1;
8157 b -= be + in_qe; if (b < 0) b = 0;
8159 r = pow(r, g1)*(1-DBL_EPSILON); rhi = pow(rhi, g1)*(1+DBL_EPSILON);
8160 g = pow(g, g1)*(1-DBL_EPSILON); ghi = pow(ghi, g1)*(1+DBL_EPSILON);
8161 b = pow(b, g1)*(1-DBL_EPSILON); bhi = pow(bhi, g1)*(1+DBL_EPSILON);
8163 /* Work out the lower and upper bounds for the gray value in the
8164 * encoded space, then work out an average and error. Remove the
8165 * previously added input quantization error at this point.
8167 gray = r * data.red_coefficient + g * data.green_coefficient +
8168 b * data.blue_coefficient - 2./32768 - out_qe;
8173 gray *= (1 - 6 * DBL_EPSILON);
8174 gray = pow(gray, data.gamma) * (1-DBL_EPSILON);
8177 grayhi = rhi * data.red_coefficient + ghi * data.green_coefficient +
8178 bhi * data.blue_coefficient + 2./32768 + out_qe;
8179 grayhi *= (1 + 6 * DBL_EPSILON);
8183 grayhi = pow(grayhi, data.gamma) * (1+DBL_EPSILON);
8185 err = (grayhi - gray) / 2;
8186 gray = (grayhi + gray) / 2;
8189 err = gray * DBL_EPSILON;
8195 /* Validate that the error is within limits (this has caused
8196 * problems before, it's much easier to detect them here.)
8198 if (err > pm->limit)
8203 pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
8204 pos = safecatd(buffer, sizeof buffer, pos, err, 6);
8205 pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
8206 pos = safecatd(buffer, sizeof buffer, pos, pm->limit, 6);
8207 png_warning(pp, buffer);
8210 #endif /* !RELEASE_BUILD */
8213 # endif /* !DIGITIZE */
8215 that->bluef = that->greenf = that->redf = gray;
8216 that->bluee = that->greene = that->rede = err;
8218 /* The sBIT is the minimum of the three colour channel sBITs. */
8219 if (that->red_sBIT > that->green_sBIT)
8220 that->red_sBIT = that->green_sBIT;
8221 if (that->red_sBIT > that->blue_sBIT)
8222 that->red_sBIT = that->blue_sBIT;
8223 that->blue_sBIT = that->green_sBIT = that->red_sBIT;
8225 /* And remove the colour bit in the type: */
8226 if (that->colour_type == PNG_COLOR_TYPE_RGB)
8227 that->colour_type = PNG_COLOR_TYPE_GRAY;
8228 else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
8229 that->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
8232 this->next->mod(this->next, that, pp, display);
8236 image_transform_png_set_rgb_to_gray_add(image_transform *this,
8237 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8244 return (colour_type & PNG_COLOR_MASK_COLOR) != 0;
8250 #define PT ITSTRUCT(rgb_to_gray)
8251 #undef image_transform_ini
8252 #define image_transform_ini image_transform_default_ini
8253 #endif /* PNG_READ_RGB_TO_GRAY_SUPPORTED */
8255 #ifdef PNG_READ_BACKGROUND_SUPPORTED
8256 /* png_set_background(png_structp, png_const_color_16p background_color,
8257 * int background_gamma_code, int need_expand, double background_gamma)
8258 * png_set_background_fixed(png_structp, png_const_color_16p background_color,
8259 * int background_gamma_code, int need_expand,
8260 * png_fixed_point background_gamma)
8262 * This ignores the gamma (at present.)
8264 #define data ITDATA(background)
8265 static image_pixel data;
8268 image_transform_png_set_background_set(const image_transform *this,
8269 transform_display *that, png_structp pp, png_infop pi)
8271 png_byte colour_type, bit_depth;
8272 png_byte random_bytes[8]; /* 8 bytes - 64 bits - the biggest pixel */
8276 /* We need a background colour, because we don't know exactly what transforms
8277 * have been set we have to supply the colour in the original file format and
8278 * so we need to know what that is! The background colour is stored in the
8279 * transform_display.
8283 /* Read the random value, for colour type 3 the background colour is actually
8284 * expressed as a 24bit rgb, not an index.
8286 colour_type = that->this.colour_type;
8287 if (colour_type == 3)
8289 colour_type = PNG_COLOR_TYPE_RGB;
8291 expand = 0; /* passing in an RGB not a pixel index */
8296 if (that->this.has_tRNS)
8297 that->this.is_transparent = 1;
8299 bit_depth = that->this.bit_depth;
8303 image_pixel_init(&data, random_bytes, colour_type,
8304 bit_depth, 0/*x*/, 0/*unused: palette*/, NULL/*format*/);
8306 /* Extract the background colour from this image_pixel, but make sure the
8307 * unused fields of 'back' are garbage.
8311 if (colour_type & PNG_COLOR_MASK_COLOR)
8313 back.red = (png_uint_16)data.red;
8314 back.green = (png_uint_16)data.green;
8315 back.blue = (png_uint_16)data.blue;
8319 back.gray = (png_uint_16)data.red;
8321 #ifdef PNG_FLOATING_POINT_SUPPORTED
8322 png_set_background(pp, &back, PNG_BACKGROUND_GAMMA_FILE, expand, 0);
8324 png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE, expand, 0);
8327 this->next->set(this->next, that, pp, pi);
8331 image_transform_png_set_background_mod(const image_transform *this,
8332 image_pixel *that, png_const_structp pp,
8333 const transform_display *display)
8335 /* Check for tRNS first: */
8336 if (that->have_tRNS && that->colour_type != PNG_COLOR_TYPE_PALETTE)
8337 image_pixel_add_alpha(that, &display->this, 1/*for background*/);
8339 /* This is only necessary if the alpha value is less than 1. */
8340 if (that->alphaf < 1)
8342 /* Now we do the background calculation without any gamma correction. */
8343 if (that->alphaf <= 0)
8345 that->redf = data.redf;
8346 that->greenf = data.greenf;
8347 that->bluef = data.bluef;
8349 that->rede = data.rede;
8350 that->greene = data.greene;
8351 that->bluee = data.bluee;
8353 that->red_sBIT= data.red_sBIT;
8354 that->green_sBIT= data.green_sBIT;
8355 that->blue_sBIT= data.blue_sBIT;
8358 else /* 0 < alpha < 1 */
8360 double alf = 1 - that->alphaf;
8362 that->redf = that->redf * that->alphaf + data.redf * alf;
8363 that->rede = that->rede * that->alphaf + data.rede * alf +
8365 that->greenf = that->greenf * that->alphaf + data.greenf * alf;
8366 that->greene = that->greene * that->alphaf + data.greene * alf +
8368 that->bluef = that->bluef * that->alphaf + data.bluef * alf;
8369 that->bluee = that->bluee * that->alphaf + data.bluee * alf +
8373 /* Remove the alpha type and set the alpha (not in that order.) */
8378 if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
8379 that->colour_type = PNG_COLOR_TYPE_RGB;
8380 else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
8381 that->colour_type = PNG_COLOR_TYPE_GRAY;
8382 /* PNG_COLOR_TYPE_PALETTE is not changed */
8384 this->next->mod(this->next, that, pp, display);
8387 #define image_transform_png_set_background_add image_transform_default_add
8392 #define PT ITSTRUCT(background)
8393 #endif /* PNG_READ_BACKGROUND_SUPPORTED */
8395 /* png_set_quantize(png_structp, png_colorp palette, int num_palette,
8396 * int maximum_colors, png_const_uint_16p histogram, int full_quantize)
8398 * Very difficult to validate this!
8402 /* The data layout transforms are handled by swapping our own channel data,
8403 * necessarily these need to happen at the end of the transform list because the
8404 * semantic of the channels changes after these are executed. Some of these,
8405 * like set_shift and set_packing, can't be done at present because they change
8406 * the layout of the data at the sub-sample level so sample() won't get the
8409 /* png_set_invert_alpha */
8410 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
8411 /* Invert the alpha channel
8413 * png_set_invert_alpha(png_structrp png_ptr)
8416 image_transform_png_set_invert_alpha_set(const image_transform *this,
8417 transform_display *that, png_structp pp, png_infop pi)
8419 png_set_invert_alpha(pp);
8420 this->next->set(this->next, that, pp, pi);
8424 image_transform_png_set_invert_alpha_mod(const image_transform *this,
8425 image_pixel *that, png_const_structp pp,
8426 const transform_display *display)
8428 if (that->colour_type & 4)
8429 that->alpha_inverted = 1;
8431 this->next->mod(this->next, that, pp, display);
8435 image_transform_png_set_invert_alpha_add(image_transform *this,
8436 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8443 /* Only has an effect on pixels with alpha: */
8444 return (colour_type & 4) != 0;
8449 #define PT ITSTRUCT(invert_alpha)
8451 #endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */
8454 #ifdef PNG_READ_BGR_SUPPORTED
8455 /* Swap R,G,B channels to order B,G,R.
8457 * png_set_bgr(png_structrp png_ptr)
8459 * This only has an effect on RGB and RGBA pixels.
8462 image_transform_png_set_bgr_set(const image_transform *this,
8463 transform_display *that, png_structp pp, png_infop pi)
8466 this->next->set(this->next, that, pp, pi);
8470 image_transform_png_set_bgr_mod(const image_transform *this,
8471 image_pixel *that, png_const_structp pp,
8472 const transform_display *display)
8474 if (that->colour_type == PNG_COLOR_TYPE_RGB ||
8475 that->colour_type == PNG_COLOR_TYPE_RGBA)
8478 this->next->mod(this->next, that, pp, display);
8482 image_transform_png_set_bgr_add(image_transform *this,
8483 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8490 return colour_type == PNG_COLOR_TYPE_RGB ||
8491 colour_type == PNG_COLOR_TYPE_RGBA;
8496 #define PT ITSTRUCT(bgr)
8498 #endif /* PNG_READ_BGR_SUPPORTED */
8500 /* png_set_swap_alpha */
8501 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
8502 /* Put the alpha channel first.
8504 * png_set_swap_alpha(png_structrp png_ptr)
8506 * This only has an effect on GA and RGBA pixels.
8509 image_transform_png_set_swap_alpha_set(const image_transform *this,
8510 transform_display *that, png_structp pp, png_infop pi)
8512 png_set_swap_alpha(pp);
8513 this->next->set(this->next, that, pp, pi);
8517 image_transform_png_set_swap_alpha_mod(const image_transform *this,
8518 image_pixel *that, png_const_structp pp,
8519 const transform_display *display)
8521 if (that->colour_type == PNG_COLOR_TYPE_GA ||
8522 that->colour_type == PNG_COLOR_TYPE_RGBA)
8523 that->alpha_first = 1;
8525 this->next->mod(this->next, that, pp, display);
8529 image_transform_png_set_swap_alpha_add(image_transform *this,
8530 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8537 return colour_type == PNG_COLOR_TYPE_GA ||
8538 colour_type == PNG_COLOR_TYPE_RGBA;
8543 #define PT ITSTRUCT(swap_alpha)
8545 #endif /* PNG_READ_SWAP_ALPHA_SUPPORTED */
8548 #ifdef PNG_READ_SWAP_SUPPORTED
8549 /* Byte swap 16-bit components.
8551 * png_set_swap(png_structrp png_ptr)
8554 image_transform_png_set_swap_set(const image_transform *this,
8555 transform_display *that, png_structp pp, png_infop pi)
8558 this->next->set(this->next, that, pp, pi);
8562 image_transform_png_set_swap_mod(const image_transform *this,
8563 image_pixel *that, png_const_structp pp,
8564 const transform_display *display)
8566 if (that->bit_depth == 16)
8569 this->next->mod(this->next, that, pp, display);
8573 image_transform_png_set_swap_add(image_transform *this,
8574 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8581 return bit_depth == 16;
8586 #define PT ITSTRUCT(swap)
8588 #endif /* PNG_READ_SWAP_SUPPORTED */
8590 #ifdef PNG_READ_FILLER_SUPPORTED
8591 /* Add a filler byte to 8-bit Gray or 24-bit RGB images.
8593 * png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags));
8600 #define data ITDATA(filler)
8608 image_transform_png_set_filler_set(const image_transform *this,
8609 transform_display *that, png_structp pp, png_infop pi)
8611 /* Need a random choice for 'before' and 'after' as well as for the
8612 * filler. The 'filler' value has all 32 bits set, but only bit_depth
8613 * will be used. At this point we don't know bit_depth.
8615 data.filler = random_u32();
8616 data.flags = random_choice();
8618 png_set_filler(pp, data.filler, data.flags);
8620 /* The standard display handling stuff also needs to know that
8621 * there is a filler, so set that here.
8623 that->this.filler = 1;
8625 this->next->set(this->next, that, pp, pi);
8629 image_transform_png_set_filler_mod(const image_transform *this,
8630 image_pixel *that, png_const_structp pp,
8631 const transform_display *display)
8633 if (that->bit_depth >= 8 &&
8634 (that->colour_type == PNG_COLOR_TYPE_RGB ||
8635 that->colour_type == PNG_COLOR_TYPE_GRAY))
8637 unsigned int max = (1U << that->bit_depth)-1;
8638 that->alpha = data.filler & max;
8639 that->alphaf = ((double)that->alpha) / max;
8642 /* The filler has been stored in the alpha channel, we must record
8643 * that this has been done for the checking later on, the color
8644 * type is faked to have an alpha channel, but libpng won't report
8645 * this; the app has to know the extra channel is there and this
8646 * was recording in standard_display::filler above.
8648 that->colour_type |= 4; /* alpha added */
8649 that->alpha_first = data.flags == PNG_FILLER_BEFORE;
8652 this->next->mod(this->next, that, pp, display);
8656 image_transform_png_set_filler_add(image_transform *this,
8657 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8662 return bit_depth >= 8 && (colour_type == PNG_COLOR_TYPE_RGB ||
8663 colour_type == PNG_COLOR_TYPE_GRAY);
8669 #define PT ITSTRUCT(filler)
8671 /* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */
8672 /* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
8673 #define data ITDATA(add_alpha)
8681 image_transform_png_set_add_alpha_set(const image_transform *this,
8682 transform_display *that, png_structp pp, png_infop pi)
8684 /* Need a random choice for 'before' and 'after' as well as for the
8685 * filler. The 'filler' value has all 32 bits set, but only bit_depth
8686 * will be used. At this point we don't know bit_depth.
8688 data.filler = random_u32();
8689 data.flags = random_choice();
8691 png_set_add_alpha(pp, data.filler, data.flags);
8692 this->next->set(this->next, that, pp, pi);
8696 image_transform_png_set_add_alpha_mod(const image_transform *this,
8697 image_pixel *that, png_const_structp pp,
8698 const transform_display *display)
8700 if (that->bit_depth >= 8 &&
8701 (that->colour_type == PNG_COLOR_TYPE_RGB ||
8702 that->colour_type == PNG_COLOR_TYPE_GRAY))
8704 unsigned int max = (1U << that->bit_depth)-1;
8705 that->alpha = data.filler & max;
8706 that->alphaf = ((double)that->alpha) / max;
8709 that->colour_type |= 4; /* alpha added */
8710 that->alpha_first = data.flags == PNG_FILLER_BEFORE;
8713 this->next->mod(this->next, that, pp, display);
8717 image_transform_png_set_add_alpha_add(image_transform *this,
8718 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8723 return bit_depth >= 8 && (colour_type == PNG_COLOR_TYPE_RGB ||
8724 colour_type == PNG_COLOR_TYPE_GRAY);
8730 #define PT ITSTRUCT(add_alpha)
8732 #endif /* PNG_READ_FILLER_SUPPORTED */
8734 /* png_set_packing */
8735 #ifdef PNG_READ_PACK_SUPPORTED
8736 /* Use 1 byte per pixel in 1, 2, or 4-bit depth files.
8738 * png_set_packing(png_structrp png_ptr)
8740 * This should only affect grayscale and palette images with less than 8 bits
8744 image_transform_png_set_packing_set(const image_transform *this,
8745 transform_display *that, png_structp pp, png_infop pi)
8747 png_set_packing(pp);
8749 this->next->set(this->next, that, pp, pi);
8753 image_transform_png_set_packing_mod(const image_transform *this,
8754 image_pixel *that, png_const_structp pp,
8755 const transform_display *display)
8757 /* The general expand case depends on what the colour type is,
8758 * low bit-depth pixel values are unpacked into bytes without
8759 * scaling, so sample_depth is not changed.
8761 if (that->bit_depth < 8) /* grayscale or palette */
8762 that->bit_depth = 8;
8764 this->next->mod(this->next, that, pp, display);
8768 image_transform_png_set_packing_add(image_transform *this,
8769 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8776 /* Nothing should happen unless the bit depth is less than 8: */
8777 return bit_depth < 8;
8782 #define PT ITSTRUCT(packing)
8784 #endif /* PNG_READ_PACK_SUPPORTED */
8786 /* png_set_packswap */
8787 #ifdef PNG_READ_PACKSWAP_SUPPORTED
8788 /* Swap pixels packed into bytes; reverses the order on screen so that
8789 * the high order bits correspond to the rightmost pixels.
8791 * png_set_packswap(png_structrp png_ptr)
8794 image_transform_png_set_packswap_set(const image_transform *this,
8795 transform_display *that, png_structp pp, png_infop pi)
8797 png_set_packswap(pp);
8798 that->this.littleendian = 1;
8799 this->next->set(this->next, that, pp, pi);
8803 image_transform_png_set_packswap_mod(const image_transform *this,
8804 image_pixel *that, png_const_structp pp,
8805 const transform_display *display)
8807 if (that->bit_depth < 8)
8808 that->littleendian = 1;
8810 this->next->mod(this->next, that, pp, display);
8814 image_transform_png_set_packswap_add(image_transform *this,
8815 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8822 return bit_depth < 8;
8827 #define PT ITSTRUCT(packswap)
8829 #endif /* PNG_READ_PACKSWAP_SUPPORTED */
8832 /* png_set_invert_mono */
8833 #ifdef PNG_READ_INVERT_MONO_SUPPORTED
8834 /* Invert the gray channel
8836 * png_set_invert_mono(png_structrp png_ptr)
8839 image_transform_png_set_invert_mono_set(const image_transform *this,
8840 transform_display *that, png_structp pp, png_infop pi)
8842 png_set_invert_mono(pp);
8843 this->next->set(this->next, that, pp, pi);
8847 image_transform_png_set_invert_mono_mod(const image_transform *this,
8848 image_pixel *that, png_const_structp pp,
8849 const transform_display *display)
8851 if (that->colour_type & 4)
8852 that->mono_inverted = 1;
8854 this->next->mod(this->next, that, pp, display);
8858 image_transform_png_set_invert_mono_add(image_transform *this,
8859 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8866 /* Only has an effect on pixels with no colour: */
8867 return (colour_type & 2) == 0;
8872 #define PT ITSTRUCT(invert_mono)
8874 #endif /* PNG_READ_INVERT_MONO_SUPPORTED */
8876 #ifdef PNG_READ_SHIFT_SUPPORTED
8877 /* png_set_shift(png_structp, png_const_color_8p true_bits)
8879 * The output pixels will be shifted by the given true_bits
8882 #define data ITDATA(shift)
8883 static png_color_8 data;
8886 image_transform_png_set_shift_set(const image_transform *this,
8887 transform_display *that, png_structp pp, png_infop pi)
8889 /* Get a random set of shifts. The shifts need to do something
8890 * to test the transform, so they are limited to the bit depth
8891 * of the input image. Notice that in the following the 'gray'
8892 * field is randomized independently. This acts as a check that
8893 * libpng does use the correct field.
8895 unsigned int depth = that->this.bit_depth;
8897 data.red = (png_byte)/*SAFE*/(random_mod(depth)+1);
8898 data.green = (png_byte)/*SAFE*/(random_mod(depth)+1);
8899 data.blue = (png_byte)/*SAFE*/(random_mod(depth)+1);
8900 data.gray = (png_byte)/*SAFE*/(random_mod(depth)+1);
8901 data.alpha = (png_byte)/*SAFE*/(random_mod(depth)+1);
8903 png_set_shift(pp, &data);
8904 this->next->set(this->next, that, pp, pi);
8908 image_transform_png_set_shift_mod(const image_transform *this,
8909 image_pixel *that, png_const_structp pp,
8910 const transform_display *display)
8912 /* Copy the correct values into the sBIT fields, libpng does not do
8913 * anything to palette data:
8915 if (that->colour_type != PNG_COLOR_TYPE_PALETTE)
8919 /* The sBIT fields are reset to the values previously sent to
8920 * png_set_shift according to the colour type.
8923 if (that->colour_type & 2) /* RGB channels */
8925 that->red_sBIT = data.red;
8926 that->green_sBIT = data.green;
8927 that->blue_sBIT = data.blue;
8930 else /* One grey channel */
8931 that->red_sBIT = that->green_sBIT = that->blue_sBIT = data.gray;
8933 that->alpha_sBIT = data.alpha;
8936 this->next->mod(this->next, that, pp, display);
8940 image_transform_png_set_shift_add(image_transform *this,
8941 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8948 return colour_type != PNG_COLOR_TYPE_PALETTE;
8953 #define PT ITSTRUCT(shift)
8955 #endif /* PNG_READ_SHIFT_SUPPORTED */
8957 #ifdef THIS_IS_THE_PROFORMA
8959 image_transform_png_set_@_set(const image_transform *this,
8960 transform_display *that, png_structp pp, png_infop pi)
8963 this->next->set(this->next, that, pp, pi);
8967 image_transform_png_set_@_mod(const image_transform *this,
8968 image_pixel *that, png_const_structp pp,
8969 const transform_display *display)
8971 this->next->mod(this->next, that, pp, display);
8975 image_transform_png_set_@_add(image_transform *this,
8976 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8988 /* This may just be 'end' if all the transforms are disabled! */
8989 static image_transform *const image_transform_first = &PT;
8992 transform_enable(const char *name)
8994 /* Everything starts out enabled, so if we see an 'enable' disabled
8995 * everything else the first time round.
8997 static int all_disabled = 0;
8999 image_transform *list = image_transform_first;
9001 while (list != &image_transform_end)
9003 if (strcmp(list->name, name) == 0)
9008 else if (!all_disabled)
9018 fprintf(stderr, "pngvalid: --transform-enable=%s: unknown transform\n",
9025 transform_disable(const char *name)
9027 image_transform *list = image_transform_first;
9029 while (list != &image_transform_end)
9031 if (strcmp(list->name, name) == 0)
9040 fprintf(stderr, "pngvalid: --transform-disable=%s: unknown transform\n",
9046 image_transform_reset_count(void)
9048 image_transform *next = image_transform_first;
9051 while (next != &image_transform_end)
9053 next->local_use = 0;
9059 /* This can only happen if we every have more than 32 transforms (excluding
9060 * the end) in the list.
9062 if (count > 32) abort();
9066 image_transform_test_counter(png_uint_32 counter, unsigned int max)
9068 /* Test the list to see if there is any point contining, given a current
9069 * counter and a 'max' value.
9071 image_transform *next = image_transform_first;
9073 while (next != &image_transform_end)
9075 /* For max 0 or 1 continue until the counter overflows: */
9078 /* Continue if any entry hasn't reacked the max. */
9079 if (max > 1 && next->local_use < max)
9084 return max <= 1 && counter == 0;
9088 image_transform_add(const image_transform **this, unsigned int max,
9089 png_uint_32 counter, char *name, size_t sizeof_name, size_t *pos,
9090 png_byte colour_type, png_byte bit_depth)
9092 for (;;) /* until we manage to add something */
9095 image_transform *list;
9097 /* Find the next counter value, if the counter is zero this is the start
9098 * of the list. This routine always returns the current counter (not the
9099 * next) so it returns 0 at the end and expects 0 at the beginning.
9101 if (counter == 0) /* first time */
9103 image_transform_reset_count();
9107 counter = random_32();
9109 else /* advance the counter */
9113 case 0: ++counter; break;
9114 case 1: counter <<= 1; break;
9115 default: counter = random_32(); break;
9119 /* Now add all these items, if possible */
9120 *this = &image_transform_end;
9121 list = image_transform_first;
9124 /* Go through the whole list adding anything that the counter selects: */
9125 while (list != &image_transform_end)
9127 if ((counter & mask) != 0 && list->enable &&
9128 (max == 0 || list->local_use < max))
9130 /* Candidate to add: */
9131 if (list->add(list, this, colour_type, bit_depth) || max == 0)
9133 /* Added, so add to the name too. */
9134 *pos = safecat(name, sizeof_name, *pos, " +");
9135 *pos = safecat(name, sizeof_name, *pos, list->name);
9140 /* Not useful and max>0, so remove it from *this: */
9144 /* And, since we know it isn't useful, stop it being added again
9147 list->local_use = max;
9155 /* Now if anything was added we have something to do. */
9156 if (*this != &image_transform_end)
9159 /* Nothing added, but was there anything in there to add? */
9160 if (!image_transform_test_counter(counter, max))
9166 perform_transform_test(png_modifier *pm)
9168 png_byte colour_type = 0;
9169 png_byte bit_depth = 0;
9170 unsigned int palette_number = 0;
9172 while (next_format(&colour_type, &bit_depth, &palette_number, pm->test_lbg,
9175 png_uint_32 counter = 0;
9179 base_pos = safecat(name, sizeof name, 0, "transform:");
9183 size_t pos = base_pos;
9184 const image_transform *list = 0;
9186 /* 'max' is currently hardwired to '1'; this should be settable on the
9189 counter = image_transform_add(&list, 1/*max*/, counter,
9190 name, sizeof name, &pos, colour_type, bit_depth);
9195 /* The command line can change this to checking interlaced images. */
9199 transform_test(pm, FILEID(colour_type, bit_depth, palette_number,
9200 pm->interlace_type, 0, 0, 0), list, name);
9209 #endif /* PNG_READ_TRANSFORMS_SUPPORTED */
9211 /********************************* GAMMA TESTS ********************************/
9212 #ifdef PNG_READ_GAMMA_SUPPORTED
9213 /* Reader callbacks and implementations, where they differ from the standard
9216 typedef struct gamma_display
9218 standard_display this;
9223 double screen_gamma;
9224 double background_gamma;
9227 int use_input_precision;
9231 png_color_16 background_color;
9233 /* Local variables */
9239 #define ALPHA_MODE_OFFSET 4
9242 gamma_display_init(gamma_display *dp, png_modifier *pm, png_uint_32 id,
9243 double file_gamma, double screen_gamma, png_byte sbit, int threshold_test,
9244 int use_input_precision, int scale16, int expand16,
9245 int do_background, const png_color_16 *pointer_to_the_background_color,
9246 double background_gamma)
9248 /* Standard fields */
9249 standard_display_init(&dp->this, &pm->this, id, do_read_interlace,
9250 pm->use_update_info);
9252 /* Parameter fields */
9254 dp->file_gamma = file_gamma;
9255 dp->screen_gamma = screen_gamma;
9256 dp->background_gamma = background_gamma;
9258 dp->threshold_test = threshold_test;
9259 dp->use_input_precision = use_input_precision;
9260 dp->scale16 = scale16;
9261 dp->expand16 = expand16;
9262 dp->do_background = do_background;
9263 if (do_background && pointer_to_the_background_color != 0)
9264 dp->background_color = *pointer_to_the_background_color;
9266 memset(&dp->background_color, 0, sizeof dp->background_color);
9268 /* Local variable fields */
9269 dp->maxerrout = dp->maxerrpc = dp->maxerrabs = 0;
9273 gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi)
9275 /* Reuse the standard stuff as appropriate. */
9276 standard_info_part1(&dp->this, pp, pi);
9278 /* If requested strip 16 to 8 bits - this is handled automagically below
9279 * because the output bit depth is read from the library. Note that there
9280 * are interactions with sBIT but, internally, libpng makes sbit at most
9281 * PNG_MAX_GAMMA_8 prior to 1.7 when doing the following.
9284 # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
9285 png_set_scale_16(pp);
9287 /* The following works both in 1.5.4 and earlier versions: */
9288 # ifdef PNG_READ_16_TO_8_SUPPORTED
9289 png_set_strip_16(pp);
9291 png_error(pp, "scale16 (16 to 8 bit conversion) not supported");
9296 # ifdef PNG_READ_EXPAND_16_SUPPORTED
9297 png_set_expand_16(pp);
9299 png_error(pp, "expand16 (8 to 16 bit conversion) not supported");
9302 if (dp->do_background >= ALPHA_MODE_OFFSET)
9304 # ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9306 /* This tests the alpha mode handling, if supported. */
9307 int mode = dp->do_background - ALPHA_MODE_OFFSET;
9309 /* The gamma value is the output gamma, and is in the standard,
9310 * non-inverted, representation. It provides a default for the PNG file
9311 * gamma, but since the file has a gAMA chunk this does not matter.
9313 const double sg = dp->screen_gamma;
9314 # ifndef PNG_FLOATING_POINT_SUPPORTED
9315 png_fixed_point g = fix(sg);
9318 # ifdef PNG_FLOATING_POINT_SUPPORTED
9319 png_set_alpha_mode(pp, mode, sg);
9321 png_set_alpha_mode_fixed(pp, mode, g);
9324 /* However, for the standard Porter-Duff algorithm the output defaults
9325 * to be linear, so if the test requires non-linear output it must be
9328 if (mode == PNG_ALPHA_STANDARD && sg != 1)
9330 # ifdef PNG_FLOATING_POINT_SUPPORTED
9331 png_set_gamma(pp, sg, dp->file_gamma);
9333 png_fixed_point f = fix(dp->file_gamma);
9334 png_set_gamma_fixed(pp, g, f);
9339 png_error(pp, "alpha mode handling not supported");
9345 /* Set up gamma processing. */
9346 # ifdef PNG_FLOATING_POINT_SUPPORTED
9347 png_set_gamma(pp, dp->screen_gamma, dp->file_gamma);
9350 png_fixed_point s = fix(dp->screen_gamma);
9351 png_fixed_point f = fix(dp->file_gamma);
9352 png_set_gamma_fixed(pp, s, f);
9356 if (dp->do_background)
9358 # ifdef PNG_READ_BACKGROUND_SUPPORTED
9359 /* NOTE: this assumes the caller provided the correct background gamma!
9361 const double bg = dp->background_gamma;
9362 # ifndef PNG_FLOATING_POINT_SUPPORTED
9363 png_fixed_point g = fix(bg);
9366 # ifdef PNG_FLOATING_POINT_SUPPORTED
9367 png_set_background(pp, &dp->background_color, dp->do_background,
9368 0/*need_expand*/, bg);
9370 png_set_background_fixed(pp, &dp->background_color,
9371 dp->do_background, 0/*need_expand*/, g);
9374 png_error(pp, "png_set_background not supported");
9380 int i = dp->this.use_update_info;
9381 /* Always do one call, even if use_update_info is 0. */
9383 png_read_update_info(pp, pi);
9387 /* Now we may get a different cbRow: */
9388 standard_info_part2(&dp->this, pp, pi, 1 /*images*/);
9391 static void PNGCBAPI
9392 gamma_info(png_structp pp, png_infop pi)
9394 gamma_info_imp(voidcast(gamma_display*, png_get_progressive_ptr(pp)), pp,
9398 /* Validate a single component value - the routine gets the input and output
9399 * sample values as unscaled PNG component values along with a cache of all the
9400 * information required to validate the values.
9402 typedef struct validate_info
9404 png_const_structp pp;
9407 int use_input_precision;
9410 unsigned int sbit_max;
9411 unsigned int isbit_shift;
9412 unsigned int outmax;
9414 double gamma_correction; /* Overall correction required. */
9415 double file_inverse; /* Inverse of file gamma. */
9416 double screen_gamma;
9417 double screen_inverse; /* Inverse of screen gamma. */
9419 double background_red; /* Linear background value, red or gray. */
9420 double background_green;
9421 double background_blue;
9427 double maxout_total; /* Total including quantization error */
9434 init_validate_info(validate_info *vi, gamma_display *dp, png_const_structp pp,
9435 int in_depth, int out_depth)
9437 unsigned int outmax = (1U<<out_depth)-1;
9442 if (dp->sbit > 0 && dp->sbit < in_depth)
9444 vi->sbit = dp->sbit;
9445 vi->isbit_shift = in_depth - dp->sbit;
9450 vi->sbit = (png_byte)in_depth;
9451 vi->isbit_shift = 0;
9454 vi->sbit_max = (1U << vi->sbit)-1;
9456 /* This mimics the libpng threshold test, '0' is used to prevent gamma
9457 * correction in the validation test.
9459 vi->screen_gamma = dp->screen_gamma;
9460 if (fabs(vi->screen_gamma-1) < PNG_GAMMA_THRESHOLD)
9461 vi->screen_gamma = vi->screen_inverse = 0;
9463 vi->screen_inverse = 1/vi->screen_gamma;
9465 vi->use_input_precision = dp->use_input_precision;
9466 vi->outmax = outmax;
9467 vi->maxabs = abserr(dp->pm, in_depth, out_depth);
9468 vi->maxpc = pcerr(dp->pm, in_depth, out_depth);
9469 vi->maxcalc = calcerr(dp->pm, in_depth, out_depth);
9470 vi->maxout = outerr(dp->pm, in_depth, out_depth);
9471 vi->outquant = output_quantization_factor(dp->pm, in_depth, out_depth);
9472 vi->maxout_total = vi->maxout + vi->outquant * .5;
9473 vi->outlog = outlog(dp->pm, in_depth, out_depth);
9475 if ((dp->this.colour_type & PNG_COLOR_MASK_ALPHA) != 0 ||
9476 (dp->this.colour_type == 3 && dp->this.is_transparent) ||
9477 ((dp->this.colour_type == 0 || dp->this.colour_type == 2) &&
9480 vi->do_background = dp->do_background;
9482 if (vi->do_background != 0)
9484 const double bg_inverse = 1/dp->background_gamma;
9487 /* Caller must at least put the gray value into the red channel */
9488 r = dp->background_color.red; r /= outmax;
9489 g = dp->background_color.green; g /= outmax;
9490 b = dp->background_color.blue; b /= outmax;
9493 /* libpng doesn't do this optimization, if we do pngvalid will fail.
9495 if (fabs(bg_inverse-1) >= PNG_GAMMA_THRESHOLD)
9498 r = pow(r, bg_inverse);
9499 g = pow(g, bg_inverse);
9500 b = pow(b, bg_inverse);
9503 vi->background_red = r;
9504 vi->background_green = g;
9505 vi->background_blue = b;
9508 else /* Do not expect any background processing */
9509 vi->do_background = 0;
9511 if (vi->do_background == 0)
9512 vi->background_red = vi->background_green = vi->background_blue = 0;
9514 vi->gamma_correction = 1/(dp->file_gamma*dp->screen_gamma);
9515 if (fabs(vi->gamma_correction-1) < PNG_GAMMA_THRESHOLD)
9516 vi->gamma_correction = 0;
9518 vi->file_inverse = 1/dp->file_gamma;
9519 if (fabs(vi->file_inverse-1) < PNG_GAMMA_THRESHOLD)
9520 vi->file_inverse = 0;
9522 vi->scale16 = dp->scale16;
9525 /* This function handles composition of a single non-alpha component. The
9526 * argument is the input sample value, in the range 0..1, and the alpha value.
9527 * The result is the composed, linear, input sample. If alpha is less than zero
9528 * this is the alpha component and the function should not be called!
9531 gamma_component_compose(int do_background, double input_sample, double alpha,
9532 double background, int *compose)
9534 switch (do_background)
9536 #ifdef PNG_READ_BACKGROUND_SUPPORTED
9537 case PNG_BACKGROUND_GAMMA_SCREEN:
9538 case PNG_BACKGROUND_GAMMA_FILE:
9539 case PNG_BACKGROUND_GAMMA_UNIQUE:
9540 /* Standard PNG background processing. */
9545 input_sample = input_sample * alpha + background * (1-alpha);
9546 if (compose != NULL)
9551 input_sample = background;
9556 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9557 case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
9558 case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
9559 /* The components are premultiplied in either case and the output is
9560 * gamma encoded (to get standard Porter-Duff we expect the output
9561 * gamma to be set to 1.0!)
9563 case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
9564 /* The optimization is that the partial-alpha entries are linear
9565 * while the opaque pixels are gamma encoded, but this only affects the
9572 input_sample *= alpha;
9573 if (compose != NULL)
9584 /* Standard cases where no compositing is done (so the component
9585 * value is already correct.)
9593 return input_sample;
9596 /* This API returns the encoded *input* component, in the range 0..1 */
9598 gamma_component_validate(const char *name, const validate_info *vi,
9599 unsigned int id, unsigned int od,
9600 const double alpha /* <0 for the alpha channel itself */,
9601 const double background /* component background value */)
9603 unsigned int isbit = id >> vi->isbit_shift;
9604 unsigned int sbit_max = vi->sbit_max;
9605 unsigned int outmax = vi->outmax;
9606 int do_background = vi->do_background;
9610 /* First check on the 'perfect' result obtained from the digitized input
9611 * value, id, and compare this against the actual digitized result, 'od'.
9612 * 'i' is the input result in the range 0..1:
9614 i = isbit; i /= sbit_max;
9616 /* Check for the fast route: if we don't do any background composition or if
9617 * this is the alpha channel ('alpha' < 0) or if the pixel is opaque then
9618 * just use the gamma_correction field to correct to the final output gamma.
9620 if (alpha == 1 /* opaque pixel component */ || !do_background
9621 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9622 || do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_PNG
9624 || (alpha < 0 /* alpha channel */
9625 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9626 && do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN
9630 /* Then get the gamma corrected version of 'i' and compare to 'od', any
9631 * error less than .5 is insignificant - just quantization of the output
9632 * value to the nearest digital value (nevertheless the error is still
9633 * recorded - it's interesting ;-)
9635 double encoded_sample = i;
9636 double encoded_error;
9638 /* alpha less than 0 indicates the alpha channel, which is always linear
9640 if (alpha >= 0 && vi->gamma_correction > 0)
9641 encoded_sample = pow(encoded_sample, vi->gamma_correction);
9642 encoded_sample *= outmax;
9644 encoded_error = fabs(od-encoded_sample);
9646 if (encoded_error > vi->dp->maxerrout)
9647 vi->dp->maxerrout = encoded_error;
9649 if (encoded_error < vi->maxout_total && encoded_error < vi->outlog)
9653 /* The slow route - attempt to do linear calculations. */
9654 /* There may be an error, or background processing is required, so calculate
9655 * the actual sample values - unencoded light intensity values. Note that in
9656 * practice these are not completely unencoded because they include a
9657 * 'viewing correction' to decrease or (normally) increase the perceptual
9658 * contrast of the image. There's nothing we can do about this - we don't
9659 * know what it is - so assume the unencoded value is perceptually linear.
9662 double input_sample = i; /* In range 0..1 */
9663 double output, error, encoded_sample, encoded_error;
9664 double es_lo, es_hi;
9665 int compose = 0; /* Set to one if composition done */
9666 int output_is_encoded; /* Set if encoded to screen gamma */
9667 int log_max_error = 1; /* Check maximum error values */
9668 png_const_charp pass = 0; /* Reason test passes (or 0 for fail) */
9670 /* Convert to linear light (with the above caveat.) The alpha channel is
9677 if (vi->file_inverse > 0)
9678 input_sample = pow(input_sample, vi->file_inverse);
9680 /* Handle the compose processing: */
9682 input_sample = gamma_component_compose(do_background, input_sample,
9683 alpha, background, &tcompose);
9689 /* And similarly for the output value, but we need to check the background
9690 * handling to linearize it correctly.
9695 output_is_encoded = vi->screen_gamma > 0;
9697 if (alpha < 0) /* The alpha channel */
9699 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9700 if (do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN)
9703 /* In all other cases the output alpha channel is linear already,
9704 * don't log errors here, they are much larger in linear data.
9706 output_is_encoded = 0;
9711 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9712 else /* A component */
9714 if (do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED &&
9715 alpha < 1) /* the optimized case - linear output */
9717 if (alpha > 0) log_max_error = 0;
9718 output_is_encoded = 0;
9723 if (output_is_encoded)
9724 output = pow(output, vi->screen_gamma);
9726 /* Calculate (or recalculate) the encoded_sample value and repeat the
9727 * check above (unnecessary if we took the fast route, but harmless.)
9729 encoded_sample = input_sample;
9730 if (output_is_encoded)
9731 encoded_sample = pow(encoded_sample, vi->screen_inverse);
9732 encoded_sample *= outmax;
9734 encoded_error = fabs(od-encoded_sample);
9736 /* Don't log errors in the alpha channel, or the 'optimized' case,
9737 * neither are significant to the overall perception.
9739 if (log_max_error && encoded_error > vi->dp->maxerrout)
9740 vi->dp->maxerrout = encoded_error;
9742 if (encoded_error < vi->maxout_total)
9744 if (encoded_error < vi->outlog)
9747 /* Test passed but error is bigger than the log limit, record why the
9750 pass = "less than maxout:\n";
9753 /* i: the original input value in the range 0..1
9755 * pngvalid calculations:
9756 * input_sample: linear result; i linearized and composed, range 0..1
9757 * encoded_sample: encoded result; input_sample scaled to output bit depth
9759 * libpng calculations:
9760 * output: linear result; od scaled to 0..1 and linearized
9761 * od: encoded result from libpng
9764 /* Now we have the numbers for real errors, both absolute values as as a
9765 * percentage of the correct value (output):
9767 error = fabs(input_sample-output);
9769 if (log_max_error && error > vi->dp->maxerrabs)
9770 vi->dp->maxerrabs = error;
9772 /* The following is an attempt to ignore the tendency of quantization to
9773 * dominate the percentage errors for lower result values:
9775 if (log_max_error && input_sample > .5)
9777 double percentage_error = error/input_sample;
9778 if (percentage_error > vi->dp->maxerrpc)
9779 vi->dp->maxerrpc = percentage_error;
9782 /* Now calculate the digitization limits for 'encoded_sample' using the
9783 * 'max' values. Note that maxout is in the encoded space but maxpc and
9784 * maxabs are in linear light space.
9786 * First find the maximum error in linear light space, range 0..1:
9789 double tmp = input_sample * vi->maxpc;
9790 if (tmp < vi->maxabs) tmp = vi->maxabs;
9791 /* If 'compose' is true the composition was done in linear space using
9792 * integer arithmetic. This introduces an extra error of +/- 0.5 (at
9793 * least) in the integer space used. 'maxcalc' records this, taking
9794 * into account the possibility that even for 16 bit output 8 bit space
9795 * may have been used.
9797 if (compose && tmp < vi->maxcalc) tmp = vi->maxcalc;
9799 /* The 'maxout' value refers to the encoded result, to compare with
9800 * this encode input_sample adjusted by the maximum error (tmp) above.
9802 es_lo = encoded_sample - vi->maxout;
9804 if (es_lo > 0 && input_sample-tmp > 0)
9806 double low_value = input_sample-tmp;
9807 if (output_is_encoded)
9808 low_value = pow(low_value, vi->screen_inverse);
9809 low_value *= outmax;
9810 if (low_value < es_lo) es_lo = low_value;
9812 /* Quantize this appropriately: */
9813 es_lo = ceil(es_lo / vi->outquant - .5) * vi->outquant;
9819 es_hi = encoded_sample + vi->maxout;
9821 if (es_hi < outmax && input_sample+tmp < 1)
9823 double high_value = input_sample+tmp;
9824 if (output_is_encoded)
9825 high_value = pow(high_value, vi->screen_inverse);
9826 high_value *= outmax;
9827 if (high_value > es_hi) es_hi = high_value;
9829 es_hi = floor(es_hi / vi->outquant + .5) * vi->outquant;
9836 /* The primary test is that the final encoded value returned by the
9837 * library should be between the two limits (inclusive) that were
9840 if (od >= es_lo && od <= es_hi)
9842 /* The value passes, but we may need to log the information anyway. */
9843 if (encoded_error < vi->outlog)
9847 pass = "within digitization limits:\n";
9851 /* There has been an error in processing, or we need to log this
9854 double is_lo, is_hi;
9856 /* pass is set at this point if either of the tests above would have
9857 * passed. Don't do these additional tests here - just log the
9858 * original [es_lo..es_hi] values.
9860 if (pass == 0 && vi->use_input_precision && vi->dp->sbit)
9862 /* Ok, something is wrong - this actually happens in current libpng
9863 * 16-to-8 processing. Assume that the input value (id, adjusted
9864 * for sbit) can be anywhere between value-.5 and value+.5 - quite a
9865 * large range if sbit is low.
9867 * NOTE: at present because the libpng gamma table stuff has been
9868 * changed to use a rounding algorithm to correct errors in 8-bit
9869 * calculations the precise sbit calculation (a shift) has been
9870 * lost. This can result in up to a +/-1 error in the presence of
9871 * an sbit less than the bit depth.
9873 # if PNG_LIBPNG_VER < 10700
9874 # define SBIT_ERROR .5
9876 # define SBIT_ERROR 1.
9878 double tmp = (isbit - SBIT_ERROR)/sbit_max;
9883 else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
9884 tmp = pow(tmp, vi->file_inverse);
9886 tmp = gamma_component_compose(do_background, tmp, alpha, background,
9889 if (output_is_encoded && tmp > 0 && tmp < 1)
9890 tmp = pow(tmp, vi->screen_inverse);
9892 is_lo = ceil(outmax * tmp - vi->maxout_total);
9897 tmp = (isbit + SBIT_ERROR)/sbit_max;
9902 else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
9903 tmp = pow(tmp, vi->file_inverse);
9905 tmp = gamma_component_compose(do_background, tmp, alpha, background,
9908 if (output_is_encoded && tmp > 0 && tmp < 1)
9909 tmp = pow(tmp, vi->screen_inverse);
9911 is_hi = floor(outmax * tmp + vi->maxout_total);
9916 if (!(od < is_lo || od > is_hi))
9918 if (encoded_error < vi->outlog)
9921 pass = "within input precision limits:\n";
9924 /* One last chance. If this is an alpha channel and the 16to8
9925 * option has been used and 'inaccurate' scaling is used then the
9926 * bit reduction is obtained by simply using the top 8 bits of the
9929 * This is only done for older libpng versions when the 'inaccurate'
9930 * (chop) method of scaling was used.
9932 # ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
9933 # if PNG_LIBPNG_VER < 10504
9934 /* This may be required for other components in the future,
9935 * but at present the presence of gamma correction effectively
9936 * prevents the errors in the component scaling (I don't quite
9937 * understand why, but since it's better this way I care not
9938 * to ask, JB 20110419.)
9940 if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
9941 vi->sbit + vi->isbit_shift == 16)
9943 tmp = ((id >> 8) - .5)/255;
9947 is_lo = ceil(outmax * tmp - vi->maxout_total);
9948 if (is_lo < 0) is_lo = 0;
9954 tmp = ((id >> 8) + .5)/255;
9958 is_hi = floor(outmax * tmp + vi->maxout_total);
9959 if (is_hi > outmax) is_hi = outmax;
9965 if (!(od < is_lo || od > is_hi))
9967 if (encoded_error < vi->outlog)
9970 pass = "within 8 bit limits:\n";
9976 else /* !use_input_precision */
9977 is_lo = es_lo, is_hi = es_hi;
9979 /* Attempt to output a meaningful error/warning message: the message
9980 * output depends on the background/composite operation being performed
9981 * because this changes what parameters were actually used above.
9985 /* Need either 1/255 or 1/65535 precision here; 3 or 6 decimal
9986 * places. Just use outmax to work out which.
9988 int precision = (outmax >= 1000 ? 6 : 3);
9989 int use_input=1, use_background=0, do_compose=0;
9993 pos = safecat(msg, sizeof msg, pos, "\n\t");
9995 /* Set up the various flags, the output_is_encoded flag above
9996 * is also used below. do_compose is just a double check.
9998 switch (do_background)
10000 # ifdef PNG_READ_BACKGROUND_SUPPORTED
10001 case PNG_BACKGROUND_GAMMA_SCREEN:
10002 case PNG_BACKGROUND_GAMMA_FILE:
10003 case PNG_BACKGROUND_GAMMA_UNIQUE:
10004 use_background = (alpha >= 0 && alpha < 1);
10006 # ifdef PNG_READ_ALPHA_MODE_SUPPORTED
10008 case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
10009 case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
10010 case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
10011 # endif /* ALPHA_MODE_SUPPORTED */
10012 do_compose = (alpha > 0 && alpha < 1);
10013 use_input = (alpha != 0);
10020 /* Check the 'compose' flag */
10021 if (compose != do_compose)
10022 png_error(vi->pp, "internal error (compose)");
10024 /* 'name' is the component name */
10025 pos = safecat(msg, sizeof msg, pos, name);
10026 pos = safecat(msg, sizeof msg, pos, "(");
10027 pos = safecatn(msg, sizeof msg, pos, id);
10028 if (use_input || pass != 0/*logging*/)
10032 /* sBIT has reduced the precision of the input: */
10033 pos = safecat(msg, sizeof msg, pos, ", sbit(");
10034 pos = safecatn(msg, sizeof msg, pos, vi->sbit);
10035 pos = safecat(msg, sizeof msg, pos, "): ");
10036 pos = safecatn(msg, sizeof msg, pos, isbit);
10038 pos = safecat(msg, sizeof msg, pos, "/");
10039 /* The output is either "id/max" or "id sbit(sbit): isbit/max" */
10040 pos = safecatn(msg, sizeof msg, pos, vi->sbit_max);
10042 pos = safecat(msg, sizeof msg, pos, ")");
10044 /* A component may have been multiplied (in linear space) by the
10045 * alpha value, 'compose' says whether this is relevant.
10047 if (compose || pass != 0)
10049 /* If any form of composition is being done report our
10050 * calculated linear value here (the code above doesn't record
10051 * the input value before composition is performed, so what
10052 * gets reported is the value after composition.)
10054 if (use_input || pass != 0)
10056 if (vi->file_inverse > 0)
10058 pos = safecat(msg, sizeof msg, pos, "^");
10059 pos = safecatd(msg, sizeof msg, pos, vi->file_inverse, 2);
10063 pos = safecat(msg, sizeof msg, pos, "[linear]");
10065 pos = safecat(msg, sizeof msg, pos, "*(alpha)");
10066 pos = safecatd(msg, sizeof msg, pos, alpha, precision);
10069 /* Now record the *linear* background value if it was used
10070 * (this function is not passed the original, non-linear,
10071 * value but it is contained in the test name.)
10073 if (use_background)
10075 pos = safecat(msg, sizeof msg, pos, use_input ? "+" : " ");
10076 pos = safecat(msg, sizeof msg, pos, "(background)");
10077 pos = safecatd(msg, sizeof msg, pos, background, precision);
10078 pos = safecat(msg, sizeof msg, pos, "*");
10079 pos = safecatd(msg, sizeof msg, pos, 1-alpha, precision);
10083 /* Report the calculated value (input_sample) and the linearized
10084 * libpng value (output) unless this is just a component gamma
10087 if (compose || alpha < 0 || pass != 0)
10089 pos = safecat(msg, sizeof msg, pos,
10090 pass != 0 ? " =\n\t" : " = ");
10091 pos = safecatd(msg, sizeof msg, pos, input_sample, precision);
10092 pos = safecat(msg, sizeof msg, pos, " (libpng: ");
10093 pos = safecatd(msg, sizeof msg, pos, output, precision);
10094 pos = safecat(msg, sizeof msg, pos, ")");
10096 /* Finally report the output gamma encoding, if any. */
10097 if (output_is_encoded)
10099 pos = safecat(msg, sizeof msg, pos, " ^");
10100 pos = safecatd(msg, sizeof msg, pos, vi->screen_inverse, 2);
10101 pos = safecat(msg, sizeof msg, pos, "(to screen) =");
10105 pos = safecat(msg, sizeof msg, pos, " [screen is linear] =");
10108 if ((!compose && alpha >= 0) || pass != 0)
10110 if (pass != 0) /* logging */
10111 pos = safecat(msg, sizeof msg, pos, "\n\t[overall:");
10113 /* This is the non-composition case, the internal linear
10114 * values are irrelevant (though the log below will reveal
10115 * them.) Output a much shorter warning/error message and report
10116 * the overall gamma correction.
10118 if (vi->gamma_correction > 0)
10120 pos = safecat(msg, sizeof msg, pos, " ^");
10121 pos = safecatd(msg, sizeof msg, pos, vi->gamma_correction, 2);
10122 pos = safecat(msg, sizeof msg, pos, "(gamma correction) =");
10126 pos = safecat(msg, sizeof msg, pos,
10127 " [no gamma correction] =");
10130 pos = safecat(msg, sizeof msg, pos, "]");
10133 /* This is our calculated encoded_sample which should (but does
10136 pos = safecat(msg, sizeof msg, pos, pass != 0 ? "\n\t" : " ");
10137 pos = safecatd(msg, sizeof msg, pos, is_lo, 1);
10138 pos = safecat(msg, sizeof msg, pos, " < ");
10139 pos = safecatd(msg, sizeof msg, pos, encoded_sample, 1);
10140 pos = safecat(msg, sizeof msg, pos, " (libpng: ");
10141 pos = safecatn(msg, sizeof msg, pos, od);
10142 pos = safecat(msg, sizeof msg, pos, ")");
10143 pos = safecat(msg, sizeof msg, pos, "/");
10144 pos = safecatn(msg, sizeof msg, pos, outmax);
10145 pos = safecat(msg, sizeof msg, pos, " < ");
10146 pos = safecatd(msg, sizeof msg, pos, is_hi, 1);
10148 if (pass == 0) /* The error condition */
10150 # ifdef PNG_WARNINGS_SUPPORTED
10151 png_warning(vi->pp, msg);
10153 store_warning(vi->pp, msg);
10157 else /* logging this value */
10158 store_verbose(&vi->dp->pm->this, vi->pp, pass, msg);
10167 gamma_image_validate(gamma_display *dp, png_const_structp pp,
10170 /* Get some constants derived from the input and output file formats: */
10171 const png_store* const ps = dp->this.ps;
10172 png_byte in_ct = dp->this.colour_type;
10173 png_byte in_bd = dp->this.bit_depth;
10174 png_uint_32 w = dp->this.w;
10175 png_uint_32 h = dp->this.h;
10176 const size_t cbRow = dp->this.cbRow;
10177 png_byte out_ct = png_get_color_type(pp, pi);
10178 png_byte out_bd = png_get_bit_depth(pp, pi);
10180 /* There are three sources of error, firstly the quantization in the
10181 * file encoding, determined by sbit and/or the file depth, secondly
10182 * the output (screen) gamma and thirdly the output file encoding.
10184 * Since this API receives the screen and file gamma in double
10185 * precision it is possible to calculate an exact answer given an input
10186 * pixel value. Therefore we assume that the *input* value is exact -
10187 * sample/maxsample - calculate the corresponding gamma corrected
10188 * output to the limits of double precision arithmetic and compare with
10189 * what libpng returns.
10191 * Since the library must quantize the output to 8 or 16 bits there is
10192 * a fundamental limit on the accuracy of the output of +/-.5 - this
10193 * quantization limit is included in addition to the other limits
10194 * specified by the parameters to the API. (Effectively, add .5
10197 * The behavior of the 'sbit' parameter is defined by section 12.5
10198 * (sample depth scaling) of the PNG spec. That section forces the
10199 * decoder to assume that the PNG values have been scaled if sBIT is
10202 * png-sample = floor( input-sample * (max-out/max-in) + .5);
10204 * This means that only a subset of the possible PNG values should
10205 * appear in the input. However, the spec allows the encoder to use a
10206 * variety of approximations to the above and doesn't require any
10207 * restriction of the values produced.
10209 * Nevertheless the spec requires that the upper 'sBIT' bits of the
10210 * value stored in a PNG file be the original sample bits.
10211 * Consequently the code below simply scales the top sbit bits by
10212 * (1<<sbit)-1 to obtain an original sample value.
10214 * Because there is limited precision in the input it is arguable that
10215 * an acceptable result is any valid result from input-.5 to input+.5.
10216 * The basic tests below do not do this, however if 'use_input_precision'
10217 * is set a subsequent test is performed above.
10219 unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U;
10222 const store_palette_entry *in_palette = dp->this.palette;
10223 int in_is_transparent = dp->this.is_transparent;
10225 int out_npalette = -1;
10226 int out_is_transparent = 0; /* Just refers to the palette case */
10227 store_palette out_palette;
10230 /* Check for row overwrite errors */
10231 store_image_check(dp->this.ps, pp, 0);
10233 /* Supply the input and output sample depths here - 8 for an indexed image,
10234 * otherwise the bit depth.
10236 init_validate_info(&vi, dp, pp, in_ct==3?8:in_bd, out_ct==3?8:out_bd);
10238 processing = (vi.gamma_correction > 0 && !dp->threshold_test)
10239 || in_bd != out_bd || in_ct != out_ct || vi.do_background;
10240 process_tRNS = dp->this.has_tRNS && vi.do_background;
10242 /* TODO: FIX THIS: MAJOR BUG! If the transformations all happen inside
10243 * the palette there is no way of finding out, because libpng fails to
10244 * update the palette on png_read_update_info. Indeed, libpng doesn't
10245 * even do the required work until much later, when it doesn't have any
10246 * info pointer. Oops. For the moment 'processing' is turned off if
10247 * out_ct is palette.
10249 if (in_ct == 3 && out_ct == 3)
10252 if (processing && out_ct == 3)
10253 out_is_transparent = read_palette(out_palette, &out_npalette, pp, pi);
10255 for (y=0; y<h; ++y)
10257 png_const_bytep pRow = store_image_row(ps, pp, 0, y);
10258 png_byte std[STANDARD_ROWMAX];
10260 transform_row(pp, std, in_ct, in_bd, y);
10266 for (x=0; x<w; ++x)
10268 double alpha = 1; /* serves as a flag value */
10270 /* Record the palette index for index images. */
10271 unsigned int in_index =
10272 in_ct == 3 ? sample(std, 3, in_bd, x, 0, 0, 0) : 256;
10273 unsigned int out_index =
10274 out_ct == 3 ? sample(std, 3, out_bd, x, 0, 0, 0) : 256;
10276 /* Handle input alpha - png_set_background will cause the output
10277 * alpha to disappear so there is nothing to check.
10279 if ((in_ct & PNG_COLOR_MASK_ALPHA) != 0 ||
10280 (in_ct == 3 && in_is_transparent))
10282 unsigned int input_alpha = in_ct == 3 ?
10283 dp->this.palette[in_index].alpha :
10284 sample(std, in_ct, in_bd, x, samples_per_pixel, 0, 0);
10286 unsigned int output_alpha = 65536 /* as a flag value */;
10290 if (out_is_transparent)
10291 output_alpha = out_palette[out_index].alpha;
10294 else if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0)
10295 output_alpha = sample(pRow, out_ct, out_bd, x,
10296 samples_per_pixel, 0, 0);
10298 if (output_alpha != 65536)
10299 alpha = gamma_component_validate("alpha", &vi, input_alpha,
10300 output_alpha, -1/*alpha*/, 0/*background*/);
10302 else /* no alpha in output */
10304 /* This is a copy of the calculation of 'i' above in order to
10305 * have the alpha value to use in the background calculation.
10307 alpha = input_alpha >> vi.isbit_shift;
10308 alpha /= vi.sbit_max;
10312 else if (process_tRNS)
10314 /* alpha needs to be set appropriately for this pixel, it is
10315 * currently 1 and needs to be 0 for an input pixel which matches
10316 * the values in tRNS.
10321 if (sample(std, in_ct, in_bd, x, 0, 0, 0) ==
10322 dp->this.transparent.red)
10327 if (sample(std, in_ct, in_bd, x, 0, 0, 0) ==
10328 dp->this.transparent.red &&
10329 sample(std, in_ct, in_bd, x, 1, 0, 0) ==
10330 dp->this.transparent.green &&
10331 sample(std, in_ct, in_bd, x, 2, 0, 0) ==
10332 dp->this.transparent.blue)
10341 /* Handle grayscale or RGB components. */
10342 if ((in_ct & PNG_COLOR_MASK_COLOR) == 0) /* grayscale */
10343 (void)gamma_component_validate("gray", &vi,
10344 sample(std, in_ct, in_bd, x, 0, 0, 0),
10345 sample(pRow, out_ct, out_bd, x, 0, 0, 0),
10346 alpha/*component*/, vi.background_red);
10347 else /* RGB or palette */
10349 (void)gamma_component_validate("red", &vi,
10350 in_ct == 3 ? in_palette[in_index].red :
10351 sample(std, in_ct, in_bd, x, 0, 0, 0),
10352 out_ct == 3 ? out_palette[out_index].red :
10353 sample(pRow, out_ct, out_bd, x, 0, 0, 0),
10354 alpha/*component*/, vi.background_red);
10356 (void)gamma_component_validate("green", &vi,
10357 in_ct == 3 ? in_palette[in_index].green :
10358 sample(std, in_ct, in_bd, x, 1, 0, 0),
10359 out_ct == 3 ? out_palette[out_index].green :
10360 sample(pRow, out_ct, out_bd, x, 1, 0, 0),
10361 alpha/*component*/, vi.background_green);
10363 (void)gamma_component_validate("blue", &vi,
10364 in_ct == 3 ? in_palette[in_index].blue :
10365 sample(std, in_ct, in_bd, x, 2, 0, 0),
10366 out_ct == 3 ? out_palette[out_index].blue :
10367 sample(pRow, out_ct, out_bd, x, 2, 0, 0),
10368 alpha/*component*/, vi.background_blue);
10373 else if (memcmp(std, pRow, cbRow) != 0)
10377 /* No transform is expected on the threshold tests. */
10378 sprintf(msg, "gamma: below threshold row %lu changed",
10381 png_error(pp, msg);
10383 } /* row (y) loop */
10385 dp->this.ps->validated = 1;
10388 static void PNGCBAPI
10389 gamma_end(png_structp ppIn, png_infop pi)
10391 png_const_structp pp = ppIn;
10392 gamma_display *dp = voidcast(gamma_display*, png_get_progressive_ptr(pp));
10394 if (!dp->this.speed)
10395 gamma_image_validate(dp, pp, pi);
10397 dp->this.ps->validated = 1;
10400 /* A single test run checking a gamma transformation.
10402 * maxabs: maximum absolute error as a fraction
10403 * maxout: maximum output error in the output units
10404 * maxpc: maximum percentage error (as a percentage)
10407 gamma_test(png_modifier *pmIn, png_byte colour_typeIn,
10408 png_byte bit_depthIn, int palette_numberIn,
10409 int interlace_typeIn,
10410 const double file_gammaIn, const double screen_gammaIn,
10411 png_byte sbitIn, int threshold_testIn,
10413 int use_input_precisionIn, int scale16In,
10414 int expand16In, int do_backgroundIn,
10415 const png_color_16 *bkgd_colorIn, double bkgd_gammaIn)
10418 context(&pmIn->this, fault);
10420 gamma_display_init(&d, pmIn, FILEID(colour_typeIn, bit_depthIn,
10421 palette_numberIn, interlace_typeIn, 0, 0, 0),
10422 file_gammaIn, screen_gammaIn, sbitIn,
10423 threshold_testIn, use_input_precisionIn, scale16In,
10424 expand16In, do_backgroundIn, bkgd_colorIn, bkgd_gammaIn);
10430 gama_modification gama_mod;
10431 srgb_modification srgb_mod;
10432 sbit_modification sbit_mod;
10434 /* For the moment don't use the png_modifier support here. */
10435 d.pm->encoding_counter = 0;
10436 modifier_set_encoding(d.pm); /* Just resets everything */
10437 d.pm->current_gamma = d.file_gamma;
10439 /* Make an appropriate modifier to set the PNG file gamma to the
10440 * given gamma value and the sBIT chunk to the given precision.
10442 d.pm->modifications = NULL;
10443 gama_modification_init(&gama_mod, d.pm, d.file_gamma);
10444 srgb_modification_init(&srgb_mod, d.pm, 127 /*delete*/);
10446 sbit_modification_init(&sbit_mod, d.pm, d.sbit);
10448 modification_reset(d.pm->modifications);
10450 /* Get a png_struct for reading the image. */
10451 pp = set_modifier_for_read(d.pm, &pi, d.this.id, name);
10452 standard_palette_init(&d.this);
10454 /* Introduce the correct read function. */
10455 if (d.pm->this.progressive)
10457 /* Share the row function with the standard implementation. */
10458 png_set_progressive_read_fn(pp, &d, gamma_info, progressive_row,
10461 /* Now feed data into the reader until we reach the end: */
10462 modifier_progressive_read(d.pm, pp, pi);
10466 /* modifier_read expects a png_modifier* */
10467 png_set_read_fn(pp, d.pm, modifier_read);
10469 /* Check the header values: */
10470 png_read_info(pp, pi);
10472 /* Process the 'info' requirements. Only one image is generated */
10473 gamma_info_imp(&d, pp, pi);
10475 sequential_row(&d.this, pp, pi, -1, 0);
10478 gamma_image_validate(&d, pp, pi);
10480 d.this.ps->validated = 1;
10483 modifier_reset(d.pm);
10485 if (d.pm->log && !d.threshold_test && !d.this.speed)
10486 fprintf(stderr, "%d bit %s %s: max error %f (%.2g, %2g%%)\n",
10487 d.this.bit_depth, colour_types[d.this.colour_type], name,
10488 d.maxerrout, d.maxerrabs, 100*d.maxerrpc);
10490 /* Log the summary values too. */
10491 if (d.this.colour_type == 0 || d.this.colour_type == 4)
10493 switch (d.this.bit_depth)
10499 if (d.maxerrout > d.pm->error_gray_2)
10500 d.pm->error_gray_2 = d.maxerrout;
10505 if (d.maxerrout > d.pm->error_gray_4)
10506 d.pm->error_gray_4 = d.maxerrout;
10511 if (d.maxerrout > d.pm->error_gray_8)
10512 d.pm->error_gray_8 = d.maxerrout;
10517 if (d.maxerrout > d.pm->error_gray_16)
10518 d.pm->error_gray_16 = d.maxerrout;
10523 png_error(pp, "bad bit depth (internal: 1)");
10527 else if (d.this.colour_type == 2 || d.this.colour_type == 6)
10529 switch (d.this.bit_depth)
10533 if (d.maxerrout > d.pm->error_color_8)
10534 d.pm->error_color_8 = d.maxerrout;
10540 if (d.maxerrout > d.pm->error_color_16)
10541 d.pm->error_color_16 = d.maxerrout;
10546 png_error(pp, "bad bit depth (internal: 2)");
10550 else if (d.this.colour_type == 3)
10552 if (d.maxerrout > d.pm->error_indexed)
10553 d.pm->error_indexed = d.maxerrout;
10558 modifier_reset(voidcast(png_modifier*,(void*)fault));
10561 static void gamma_threshold_test(png_modifier *pm, png_byte colour_type,
10562 png_byte bit_depth, int interlace_type, double file_gamma,
10563 double screen_gamma)
10567 pos = safecat(name, sizeof name, pos, "threshold ");
10568 pos = safecatd(name, sizeof name, pos, file_gamma, 3);
10569 pos = safecat(name, sizeof name, pos, "/");
10570 pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
10572 (void)gamma_test(pm, colour_type, bit_depth, 0/*palette*/, interlace_type,
10573 file_gamma, screen_gamma, 0/*sBIT*/, 1/*threshold test*/, name,
10574 0 /*no input precision*/,
10575 0 /*no scale16*/, 0 /*no expand16*/, 0 /*no background*/, 0 /*hence*/,
10576 0 /*no background gamma*/);
10580 perform_gamma_threshold_tests(png_modifier *pm)
10582 png_byte colour_type = 0;
10583 png_byte bit_depth = 0;
10584 unsigned int palette_number = 0;
10586 /* Don't test more than one instance of each palette - it's pointless, in
10587 * fact this test is somewhat excessive since libpng doesn't make this
10588 * decision based on colour type or bit depth!
10590 * CHANGED: now test two palettes and, as a side effect, images with and
10593 while (next_format(&colour_type, &bit_depth, &palette_number,
10594 pm->test_lbg_gamma_threshold, pm->test_tRNS))
10595 if (palette_number < 2)
10597 double test_gamma = 1.0;
10598 while (test_gamma >= .4)
10600 /* There's little point testing the interlacing vs non-interlacing,
10601 * but this can be set from the command line.
10603 gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
10604 test_gamma, 1/test_gamma);
10608 /* And a special test for sRGB */
10609 gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
10617 static void gamma_transform_test(png_modifier *pm,
10618 png_byte colour_type, png_byte bit_depth,
10619 int palette_number,
10620 int interlace_type, const double file_gamma,
10621 const double screen_gamma, png_byte sbit,
10622 int use_input_precision, int scale16)
10627 if (sbit != bit_depth && sbit != 0)
10629 pos = safecat(name, sizeof name, pos, "sbit(");
10630 pos = safecatn(name, sizeof name, pos, sbit);
10631 pos = safecat(name, sizeof name, pos, ") ");
10635 pos = safecat(name, sizeof name, pos, "gamma ");
10638 pos = safecat(name, sizeof name, pos, "16to8 ");
10640 pos = safecatd(name, sizeof name, pos, file_gamma, 3);
10641 pos = safecat(name, sizeof name, pos, "->");
10642 pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
10644 gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
10645 file_gamma, screen_gamma, sbit, 0, name, use_input_precision,
10646 scale16, pm->test_gamma_expand16, 0 , 0, 0);
10649 static void perform_gamma_transform_tests(png_modifier *pm)
10651 png_byte colour_type = 0;
10652 png_byte bit_depth = 0;
10653 unsigned int palette_number = 0;
10655 while (next_format(&colour_type, &bit_depth, &palette_number,
10656 pm->test_lbg_gamma_transform, pm->test_tRNS))
10660 for (i=0; i<pm->ngamma_tests; ++i)
10662 for (j=0; j<pm->ngamma_tests; ++j)
10666 gamma_transform_test(pm, colour_type, bit_depth, palette_number,
10667 pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
10668 0/*sBIT*/, pm->use_input_precision, 0/*do not scale16*/);
10678 static void perform_gamma_sbit_tests(png_modifier *pm)
10682 /* The only interesting cases are colour and grayscale, alpha is ignored here
10683 * for overall speed. Only bit depths where sbit is less than the bit depth
10686 for (sbit=pm->sbitlow; sbit<(1<<READ_BDHI); ++sbit)
10688 png_byte colour_type = 0, bit_depth = 0;
10689 unsigned int npalette = 0;
10691 while (next_format(&colour_type, &bit_depth, &npalette,
10692 pm->test_lbg_gamma_sbit, pm->test_tRNS))
10693 if ((colour_type & PNG_COLOR_MASK_ALPHA) == 0 &&
10694 ((colour_type == 3 && sbit < 8) ||
10695 (colour_type != 3 && sbit < bit_depth)))
10699 for (i=0; i<pm->ngamma_tests; ++i)
10703 for (j=0; j<pm->ngamma_tests; ++j)
10707 gamma_transform_test(pm, colour_type, bit_depth, npalette,
10708 pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
10709 sbit, pm->use_input_precision_sbit, 0 /*scale16*/);
10720 /* Note that this requires a 16 bit source image but produces 8 bit output, so
10721 * we only need the 16bit write support, but the 16 bit images are only
10722 * generated if DO_16BIT is defined.
10725 static void perform_gamma_scale16_tests(png_modifier *pm)
10727 # ifndef PNG_MAX_GAMMA_8
10728 # define PNG_MAX_GAMMA_8 11
10730 # if defined PNG_MAX_GAMMA_8 || PNG_LIBPNG_VER < 10700
10731 # define SBIT_16_TO_8 PNG_MAX_GAMMA_8
10733 # define SBIT_16_TO_8 16
10735 /* Include the alpha cases here. Note that sbit matches the internal value
10736 * used by the library - otherwise we will get spurious errors from the
10737 * internal sbit style approximation.
10739 * The threshold test is here because otherwise the 16 to 8 conversion will
10740 * proceed *without* gamma correction, and the tests above will fail (but not
10741 * by much) - this could be fixed, it only appears with the -g option.
10744 for (i=0; i<pm->ngamma_tests; ++i)
10746 for (j=0; j<pm->ngamma_tests; ++j)
10749 fabs(pm->gammas[j]/pm->gammas[i]-1) >= PNG_GAMMA_THRESHOLD)
10751 gamma_transform_test(pm, 0, 16, 0, pm->interlace_type,
10752 1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
10753 pm->use_input_precision_16to8, 1 /*scale16*/);
10758 gamma_transform_test(pm, 2, 16, 0, pm->interlace_type,
10759 1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
10760 pm->use_input_precision_16to8, 1 /*scale16*/);
10765 gamma_transform_test(pm, 4, 16, 0, pm->interlace_type,
10766 1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
10767 pm->use_input_precision_16to8, 1 /*scale16*/);
10772 gamma_transform_test(pm, 6, 16, 0, pm->interlace_type,
10773 1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
10774 pm->use_input_precision_16to8, 1 /*scale16*/);
10782 #endif /* 16 to 8 bit conversion */
10784 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
10785 defined(PNG_READ_ALPHA_MODE_SUPPORTED)
10786 static void gamma_composition_test(png_modifier *pm,
10787 png_byte colour_type, png_byte bit_depth,
10788 int palette_number,
10789 int interlace_type, const double file_gamma,
10790 const double screen_gamma,
10791 int use_input_precision, int do_background,
10795 png_const_charp base;
10798 png_color_16 background;
10800 /* Make up a name and get an appropriate background gamma value. */
10801 switch (do_background)
10805 bg = 4; /* should not be used */
10807 case PNG_BACKGROUND_GAMMA_SCREEN:
10808 base = " bckg(Screen):";
10809 bg = 1/screen_gamma;
10811 case PNG_BACKGROUND_GAMMA_FILE:
10812 base = " bckg(File):";
10815 case PNG_BACKGROUND_GAMMA_UNIQUE:
10816 base = " bckg(Unique):";
10817 /* This tests the handling of a unique value, the math is such that the
10818 * value tends to be <1, but is neither screen nor file (even if they
10821 bg = (file_gamma + screen_gamma) / 3;
10823 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
10824 case ALPHA_MODE_OFFSET + PNG_ALPHA_PNG:
10825 base = " alpha(PNG)";
10826 bg = 4; /* should not be used */
10828 case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
10829 base = " alpha(Porter-Duff)";
10830 bg = 4; /* should not be used */
10832 case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
10833 base = " alpha(Optimized)";
10834 bg = 4; /* should not be used */
10836 case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
10837 base = " alpha(Broken)";
10838 bg = 4; /* should not be used */
10843 /* Use random background values - the background is always presented in the
10844 * output space (8 or 16 bit components).
10846 if (expand_16 || bit_depth == 16)
10848 png_uint_32 r = random_32();
10850 background.red = (png_uint_16)r;
10851 background.green = (png_uint_16)(r >> 16);
10853 background.blue = (png_uint_16)r;
10854 background.gray = (png_uint_16)(r >> 16);
10856 /* In earlier libpng versions, those where DIGITIZE is set, any background
10857 * gamma correction in the expand16 case was done using 8-bit gamma
10858 * correction tables, resulting in larger errors. To cope with those
10859 * cases use a 16-bit background value which will handle this gamma
10863 if (expand_16 && (do_background == PNG_BACKGROUND_GAMMA_UNIQUE ||
10864 do_background == PNG_BACKGROUND_GAMMA_FILE) &&
10865 fabs(bg*screen_gamma-1) > PNG_GAMMA_THRESHOLD)
10867 /* The background values will be looked up in an 8-bit table to do
10868 * the gamma correction, so only select values which are an exact
10869 * match for the 8-bit table entries:
10871 background.red = (png_uint_16)((background.red >> 8) * 257);
10872 background.green = (png_uint_16)((background.green >> 8) * 257);
10873 background.blue = (png_uint_16)((background.blue >> 8) * 257);
10874 background.gray = (png_uint_16)((background.gray >> 8) * 257);
10879 else /* 8 bit colors */
10881 png_uint_32 r = random_32();
10883 background.red = (png_byte)r;
10884 background.green = (png_byte)(r >> 8);
10885 background.blue = (png_byte)(r >> 16);
10886 background.gray = (png_byte)(r >> 24);
10889 background.index = 193; /* rgb(193,193,193) to detect errors */
10891 if (!(colour_type & PNG_COLOR_MASK_COLOR))
10893 /* Because, currently, png_set_background is always called with
10894 * 'need_expand' false in this case and because the gamma test itself
10895 * doesn't cause an expand to 8-bit for lower bit depths the colour must
10896 * be reduced to the correct range.
10899 background.gray &= (png_uint_16)((1U << bit_depth)-1);
10901 /* Grayscale input, we do not convert to RGB (TBD), so we must set the
10902 * background to gray - else libpng seems to fail.
10904 background.red = background.green = background.blue = background.gray;
10907 pos = safecat(name, sizeof name, pos, "gamma ");
10908 pos = safecatd(name, sizeof name, pos, file_gamma, 3);
10909 pos = safecat(name, sizeof name, pos, "->");
10910 pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
10912 pos = safecat(name, sizeof name, pos, base);
10913 if (do_background < ALPHA_MODE_OFFSET)
10915 /* Include the background color and gamma in the name: */
10916 pos = safecat(name, sizeof name, pos, "(");
10917 /* This assumes no expand gray->rgb - the current code won't handle that!
10919 if (colour_type & PNG_COLOR_MASK_COLOR)
10921 pos = safecatn(name, sizeof name, pos, background.red);
10922 pos = safecat(name, sizeof name, pos, ",");
10923 pos = safecatn(name, sizeof name, pos, background.green);
10924 pos = safecat(name, sizeof name, pos, ",");
10925 pos = safecatn(name, sizeof name, pos, background.blue);
10928 pos = safecatn(name, sizeof name, pos, background.gray);
10929 pos = safecat(name, sizeof name, pos, ")^");
10930 pos = safecatd(name, sizeof name, pos, bg, 3);
10933 gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
10934 file_gamma, screen_gamma, 0/*sBIT*/, 0, name, use_input_precision,
10935 0/*strip 16*/, expand_16, do_background, &background, bg);
10940 perform_gamma_composition_tests(png_modifier *pm, int do_background,
10943 png_byte colour_type = 0;
10944 png_byte bit_depth = 0;
10945 unsigned int palette_number = 0;
10947 /* Skip the non-alpha cases - there is no setting of a transparency colour at
10950 * TODO: incorrect; the palette case sets tRNS and, now RGB and gray do,
10951 * however the palette case fails miserably so is commented out below.
10953 while (next_format(&colour_type, &bit_depth, &palette_number,
10954 pm->test_lbg_gamma_composition, pm->test_tRNS))
10955 if ((colour_type & PNG_COLOR_MASK_ALPHA) != 0
10956 #if 0 /* TODO: FIXME */
10957 /*TODO: FIXME: this should work */
10958 || colour_type == 3
10960 || (colour_type != 3 && palette_number != 0))
10964 /* Don't skip the i==j case here - it's relevant. */
10965 for (i=0; i<pm->ngamma_tests; ++i)
10967 for (j=0; j<pm->ngamma_tests; ++j)
10969 gamma_composition_test(pm, colour_type, bit_depth, palette_number,
10970 pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
10971 pm->use_input_precision, do_background, expand_16);
10979 #endif /* READ_BACKGROUND || READ_ALPHA_MODE */
10982 init_gamma_errors(png_modifier *pm)
10984 /* Use -1 to catch tests that were not actually run */
10985 pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = -1.;
10986 pm->error_color_8 = -1.;
10987 pm->error_indexed = -1.;
10988 pm->error_gray_16 = pm->error_color_16 = -1.;
10992 print_one(const char *leader, double err)
10995 printf(" %s %.5f\n", leader, err);
10999 summarize_gamma_errors(png_modifier *pm, png_const_charp who, int low_bit_depth,
11005 printf("\nGamma correction with %s:\n", who);
11008 printf("\nBasic gamma correction:\n");
11012 print_one(" 2 bit gray: ", pm->error_gray_2);
11013 print_one(" 4 bit gray: ", pm->error_gray_4);
11014 print_one(" 8 bit gray: ", pm->error_gray_8);
11015 print_one(" 8 bit color:", pm->error_color_8);
11017 print_one(" indexed: ", pm->error_indexed);
11020 print_one("16 bit gray: ", pm->error_gray_16);
11021 print_one("16 bit color:", pm->error_color_16);
11027 perform_gamma_test(png_modifier *pm, int summary)
11029 /*TODO: remove this*/
11030 /* Save certain values for the temporary overrides below. */
11031 unsigned int calculations_use_input_precision =
11032 pm->calculations_use_input_precision;
11033 # ifdef PNG_READ_BACKGROUND_SUPPORTED
11034 double maxout8 = pm->maxout8;
11037 /* First some arbitrary no-transform tests: */
11038 if (!pm->this.speed && pm->test_gamma_threshold)
11040 perform_gamma_threshold_tests(pm);
11046 /* Now some real transforms. */
11047 if (pm->test_gamma_transform)
11052 printf("Gamma correction error summary\n\n");
11053 printf("The printed value is the maximum error in the pixel values\n");
11054 printf("calculated by the libpng gamma correction code. The error\n");
11055 printf("is calculated as the difference between the output pixel\n");
11056 printf("value (always an integer) and the ideal value from the\n");
11057 printf("libpng specification (typically not an integer).\n\n");
11059 printf("Expect this value to be less than .5 for 8 bit formats,\n");
11060 printf("less than 1 for formats with fewer than 8 bits and a small\n");
11061 printf("number (typically less than 5) for the 16 bit formats.\n");
11062 printf("For performance reasons the value for 16 bit formats\n");
11063 printf("increases when the image file includes an sBIT chunk.\n");
11067 init_gamma_errors(pm);
11068 /*TODO: remove this. Necessary because the current libpng
11069 * implementation works in 8 bits:
11071 if (pm->test_gamma_expand16)
11072 pm->calculations_use_input_precision = 1;
11073 perform_gamma_transform_tests(pm);
11074 if (!calculations_use_input_precision)
11075 pm->calculations_use_input_precision = 0;
11078 summarize_gamma_errors(pm, NULL/*who*/, 1/*low bit depth*/, 1/*indexed*/);
11084 /* The sbit tests produce much larger errors: */
11085 if (pm->test_gamma_sbit)
11087 init_gamma_errors(pm);
11088 perform_gamma_sbit_tests(pm);
11091 summarize_gamma_errors(pm, "sBIT", pm->sbitlow < 8U, 1/*indexed*/);
11097 #ifdef DO_16BIT /* Should be READ_16BIT_SUPPORTED */
11098 if (pm->test_gamma_scale16)
11100 /* The 16 to 8 bit strip operations: */
11101 init_gamma_errors(pm);
11102 perform_gamma_scale16_tests(pm);
11107 printf("\nGamma correction with 16 to 8 bit reduction:\n");
11108 printf(" 16 bit gray: %.5f\n", pm->error_gray_16);
11109 printf(" 16 bit color: %.5f\n", pm->error_color_16);
11118 #ifdef PNG_READ_BACKGROUND_SUPPORTED
11119 if (pm->test_gamma_background)
11121 init_gamma_errors(pm);
11123 /*TODO: remove this. Necessary because the current libpng
11124 * implementation works in 8 bits:
11126 if (pm->test_gamma_expand16)
11128 pm->calculations_use_input_precision = 1;
11129 pm->maxout8 = .499; /* because the 16 bit background is smashed */
11131 perform_gamma_composition_tests(pm, PNG_BACKGROUND_GAMMA_UNIQUE,
11132 pm->test_gamma_expand16);
11133 if (!calculations_use_input_precision)
11134 pm->calculations_use_input_precision = 0;
11135 pm->maxout8 = maxout8;
11138 summarize_gamma_errors(pm, "background", 1, 0/*indexed*/);
11145 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
11146 if (pm->test_gamma_alpha_mode)
11150 init_gamma_errors(pm);
11152 /*TODO: remove this. Necessary because the current libpng
11153 * implementation works in 8 bits:
11155 if (pm->test_gamma_expand16)
11156 pm->calculations_use_input_precision = 1;
11157 for (do_background = ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD;
11158 do_background <= ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN && !fail(pm);
11160 perform_gamma_composition_tests(pm, do_background,
11161 pm->test_gamma_expand16);
11162 if (!calculations_use_input_precision)
11163 pm->calculations_use_input_precision = 0;
11166 summarize_gamma_errors(pm, "alpha mode", 1, 0/*indexed*/);
11173 #endif /* PNG_READ_GAMMA_SUPPORTED */
11174 #endif /* PNG_READ_SUPPORTED */
11176 /* INTERLACE MACRO VALIDATION */
11177 /* This is copied verbatim from the specification, it is simply the pass
11178 * number in which each pixel in each 8x8 tile appears. The array must
11179 * be indexed adam7[y][x] and notice that the pass numbers are based at
11180 * 1, not 0 - the base libpng uses.
11183 png_byte adam7[8][8] =
11185 { 1,6,4,6,2,6,4,6 },
11186 { 7,7,7,7,7,7,7,7 },
11187 { 5,6,5,6,5,6,5,6 },
11188 { 7,7,7,7,7,7,7,7 },
11189 { 3,6,4,6,3,6,4,6 },
11190 { 7,7,7,7,7,7,7,7 },
11191 { 5,6,5,6,5,6,5,6 },
11192 { 7,7,7,7,7,7,7,7 }
11195 /* This routine validates all the interlace support macros in png.h for
11196 * a variety of valid PNG widths and heights. It uses a number of similarly
11197 * named internal routines that feed off the above array.
11200 png_pass_start_row(int pass)
11204 for (y=0; y<8; ++y)
11205 for (x=0; x<8; ++x)
11206 if (adam7[y][x] == pass)
11212 png_pass_start_col(int pass)
11216 for (x=0; x<8; ++x)
11217 for (y=0; y<8; ++y)
11218 if (adam7[y][x] == pass)
11224 png_pass_row_shift(int pass)
11226 int x, y, base=(-1), inc=8;
11228 for (y=0; y<8; ++y)
11230 for (x=0; x<8; ++x)
11232 if (adam7[y][x] == pass)
11236 else if (base == y)
11238 else if (inc == y-base)
11241 inc = y-base, base=y;
11242 else if (inc != y-base)
11243 return 0xff; /* error - more than one 'inc' value! */
11248 if (base == (-1)) return 0xfe; /* error - no row in pass! */
11250 /* The shift is always 1, 2 or 3 - no pass has all the rows! */
11259 /* error - unrecognized 'inc' */
11260 return (inc << 8) + 0xfd;
11264 png_pass_col_shift(int pass)
11266 int x, y, base=(-1), inc=8;
11268 for (x=0; x<8; ++x)
11270 for (y=0; y<8; ++y)
11272 if (adam7[y][x] == pass)
11276 else if (base == x)
11278 else if (inc == x-base)
11281 inc = x-base, base=x;
11282 else if (inc != x-base)
11283 return 0xff; /* error - more than one 'inc' value! */
11288 if (base == (-1)) return 0xfe; /* error - no row in pass! */
11290 /* The shift is always 1, 2 or 3 - no pass has all the rows! */
11293 case 1: return 0; /* pass 7 has all the columns */
11300 /* error - unrecognized 'inc' */
11301 return (inc << 8) + 0xfd;
11305 png_row_from_pass_row(png_uint_32 yIn, int pass)
11307 /* By examination of the array: */
11310 case 0: return yIn * 8;
11311 case 1: return yIn * 8;
11312 case 2: return yIn * 8 + 4;
11313 case 3: return yIn * 4;
11314 case 4: return yIn * 4 + 2;
11315 case 5: return yIn * 2;
11316 case 6: return yIn * 2 + 1;
11320 return 0xff; /* bad pass number */
11324 png_col_from_pass_col(png_uint_32 xIn, int pass)
11326 /* By examination of the array: */
11329 case 0: return xIn * 8;
11330 case 1: return xIn * 8 + 4;
11331 case 2: return xIn * 4;
11332 case 3: return xIn * 4 + 2;
11333 case 4: return xIn * 2;
11334 case 5: return xIn * 2 + 1;
11335 case 6: return xIn;
11339 return 0xff; /* bad pass number */
11343 png_row_in_interlace_pass(png_uint_32 y, int pass)
11345 /* Is row 'y' in pass 'pass'? */
11349 for (x=0; x<8; ++x)
11350 if (adam7[y][x] == pass)
11357 png_col_in_interlace_pass(png_uint_32 x, int pass)
11359 /* Is column 'x' in pass 'pass'? */
11363 for (y=0; y<8; ++y)
11364 if (adam7[y][x] == pass)
11371 png_pass_rows(png_uint_32 height, int pass)
11373 png_uint_32 tiles = height>>3;
11374 png_uint_32 rows = 0;
11379 for (y=0; y<8; ++y)
11381 for (x=0; x<8; ++x)
11383 if (adam7[y][x] == pass)
11386 if (y < height) ++rows;
11387 break; /* i.e. break the 'x', column, loop. */
11396 png_pass_cols(png_uint_32 width, int pass)
11398 png_uint_32 tiles = width>>3;
11399 png_uint_32 cols = 0;
11404 for (x=0; x<8; ++x)
11406 for (y=0; y<8; ++y)
11408 if (adam7[y][x] == pass)
11411 if (x < width) ++cols;
11412 break; /* i.e. break the 'y', row, loop. */
11421 perform_interlace_macro_validation(void)
11423 /* The macros to validate, first those that depend only on pass:
11425 * PNG_PASS_START_ROW(pass)
11426 * PNG_PASS_START_COL(pass)
11427 * PNG_PASS_ROW_SHIFT(pass)
11428 * PNG_PASS_COL_SHIFT(pass)
11432 for (pass=0; pass<7; ++pass)
11434 png_uint_32 m, f, v;
11436 m = PNG_PASS_START_ROW(pass);
11437 f = png_pass_start_row(pass);
11440 fprintf(stderr, "PNG_PASS_START_ROW(%d) = %u != %x\n", pass, m, f);
11444 m = PNG_PASS_START_COL(pass);
11445 f = png_pass_start_col(pass);
11448 fprintf(stderr, "PNG_PASS_START_COL(%d) = %u != %x\n", pass, m, f);
11452 m = PNG_PASS_ROW_SHIFT(pass);
11453 f = png_pass_row_shift(pass);
11456 fprintf(stderr, "PNG_PASS_ROW_SHIFT(%d) = %u != %x\n", pass, m, f);
11460 m = PNG_PASS_COL_SHIFT(pass);
11461 f = png_pass_col_shift(pass);
11464 fprintf(stderr, "PNG_PASS_COL_SHIFT(%d) = %u != %x\n", pass, m, f);
11468 /* Macros that depend on the image or sub-image height too:
11470 * PNG_PASS_ROWS(height, pass)
11471 * PNG_PASS_COLS(width, pass)
11472 * PNG_ROW_FROM_PASS_ROW(yIn, pass)
11473 * PNG_COL_FROM_PASS_COL(xIn, pass)
11474 * PNG_ROW_IN_INTERLACE_PASS(y, pass)
11475 * PNG_COL_IN_INTERLACE_PASS(x, pass)
11479 /* The first two tests overflow if the pass row or column is outside
11480 * the possible range for a 32-bit result. In fact the values should
11481 * never be outside the range for a 31-bit result, but checking for 32
11482 * bits here ensures that if an app uses a bogus pass row or column
11483 * (just so long as it fits in a 32 bit integer) it won't get a
11484 * possibly dangerous overflow.
11486 /* First the base 0 stuff: */
11487 if (v < png_pass_rows(0xFFFFFFFFU, pass))
11489 m = PNG_ROW_FROM_PASS_ROW(v, pass);
11490 f = png_row_from_pass_row(v, pass);
11493 fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
11499 if (v < png_pass_cols(0xFFFFFFFFU, pass))
11501 m = PNG_COL_FROM_PASS_COL(v, pass);
11502 f = png_col_from_pass_col(v, pass);
11505 fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
11511 m = PNG_ROW_IN_INTERLACE_PASS(v, pass);
11512 f = png_row_in_interlace_pass(v, pass);
11515 fprintf(stderr, "PNG_ROW_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
11520 m = PNG_COL_IN_INTERLACE_PASS(v, pass);
11521 f = png_col_in_interlace_pass(v, pass);
11524 fprintf(stderr, "PNG_COL_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
11529 /* Then the base 1 stuff: */
11531 m = PNG_PASS_ROWS(v, pass);
11532 f = png_pass_rows(v, pass);
11535 fprintf(stderr, "PNG_PASS_ROWS(%u, %d) = %u != %x\n",
11540 m = PNG_PASS_COLS(v, pass);
11541 f = png_pass_cols(v, pass);
11544 fprintf(stderr, "PNG_PASS_COLS(%u, %d) = %u != %x\n",
11549 /* Move to the next v - the stepping algorithm starts skipping
11550 * values above 1024.
11554 if (v == PNG_UINT_31_MAX)
11558 if (v >= PNG_UINT_31_MAX)
11559 v = PNG_UINT_31_MAX-1;
11565 /* Test color encodings. These values are back-calculated from the published
11566 * chromaticities. The values are accurate to about 14 decimal places; 15 are
11567 * given. These values are much more accurate than the ones given in the spec,
11568 * which typically don't exceed 4 decimal places. This allows testing of the
11569 * libpng code to its theoretical accuracy of 4 decimal places. (If pngvalid
11570 * used the published errors the 'slack' permitted would have to be +/-.5E-4 or
11573 * The png_modifier code assumes that encodings[0] is sRGB and treats it
11574 * specially: do not change the first entry in this list!
11576 static const color_encoding test_encodings[] =
11578 /* sRGB: must be first in this list! */
11579 /*gamma:*/ { 1/2.2,
11580 /*red: */ { 0.412390799265959, 0.212639005871510, 0.019330818715592 },
11581 /*green:*/ { 0.357584339383878, 0.715168678767756, 0.119194779794626 },
11582 /*blue: */ { 0.180480788401834, 0.072192315360734, 0.950532152249660} },
11583 /* Kodak ProPhoto (wide gamut) */
11584 /*gamma:*/ { 1/1.6 /*approximate: uses 1.8 power law compared to sRGB 2.4*/,
11585 /*red: */ { 0.797760489672303, 0.288071128229293, 0.000000000000000 },
11586 /*green:*/ { 0.135185837175740, 0.711843217810102, 0.000000000000000 },
11587 /*blue: */ { 0.031349349581525, 0.000085653960605, 0.825104602510460} },
11588 /* Adobe RGB (1998) */
11589 /*gamma:*/ { 1/(2+51./256),
11590 /*red: */ { 0.576669042910131, 0.297344975250536, 0.027031361386412 },
11591 /*green:*/ { 0.185558237906546, 0.627363566255466, 0.070688852535827 },
11592 /*blue: */ { 0.188228646234995, 0.075291458493998, 0.991337536837639} },
11593 /* Adobe Wide Gamut RGB */
11594 /*gamma:*/ { 1/(2+51./256),
11595 /*red: */ { 0.716500716779386, 0.258728243040113, 0.000000000000000 },
11596 /*green:*/ { 0.101020574397477, 0.724682314948566, 0.051211818965388 },
11597 /*blue: */ { 0.146774385252705, 0.016589442011321, 0.773892783545073} },
11598 /* Fake encoding which selects just the green channel */
11599 /*gamma:*/ { 1.45/2.2, /* the 'Mac' gamma */
11600 /*red: */ { 0.716500716779386, 0.000000000000000, 0.000000000000000 },
11601 /*green:*/ { 0.101020574397477, 1.000000000000000, 0.051211818965388 },
11602 /*blue: */ { 0.146774385252705, 0.000000000000000, 0.773892783545073} },
11607 * This attempts to trap signals and escape without crashing. It needs a
11608 * context pointer so that it can throw an exception (call longjmp) to recover
11609 * from the condition; this is handled by making the png_modifier used by 'main'
11610 * into a global variable.
11612 static png_modifier pm;
11614 static void signal_handler(int signum)
11620 pos = safecat(msg, sizeof msg, pos, "caught signal: ");
11625 pos = safecat(msg, sizeof msg, pos, "abort");
11629 pos = safecat(msg, sizeof msg, pos, "floating point exception");
11633 pos = safecat(msg, sizeof msg, pos, "illegal instruction");
11637 pos = safecat(msg, sizeof msg, pos, "interrupt");
11641 pos = safecat(msg, sizeof msg, pos, "invalid memory access");
11645 pos = safecat(msg, sizeof msg, pos, "termination request");
11649 pos = safecat(msg, sizeof msg, pos, "unknown ");
11650 pos = safecatn(msg, sizeof msg, pos, signum);
11654 store_log(&pm.this, NULL/*png_structp*/, msg, 1/*error*/);
11656 /* And finally throw an exception so we can keep going, unless this is
11657 * SIGTERM in which case stop now.
11659 if (signum != SIGTERM)
11661 struct exception_context *the_exception_context =
11662 &pm.this.exception_context;
11672 int main(int argc, char **argv)
11674 int summary = 1; /* Print the error summary at the end */
11675 int memstats = 0; /* Print memory statistics at the end */
11677 /* Create the given output file on success: */
11678 const char *touch = NULL;
11680 /* This is an array of standard gamma values (believe it or not I've seen
11681 * every one of these mentioned somewhere.)
11683 * In the following list the most useful values are first!
11686 gammas[]={2.2, 1.0, 2.2/1.45, 1.8, 1.5, 2.4, 2.5, 2.62, 2.9};
11688 /* This records the command and arguments: */
11690 char command[1024];
11692 anon_context(&pm.this);
11694 gnu_volatile(summary)
11695 gnu_volatile(memstats)
11696 gnu_volatile(touch)
11698 /* Add appropriate signal handlers, just the ANSI specified ones: */
11699 signal(SIGABRT, signal_handler);
11700 signal(SIGFPE, signal_handler);
11701 signal(SIGILL, signal_handler);
11702 signal(SIGINT, signal_handler);
11703 signal(SIGSEGV, signal_handler);
11704 signal(SIGTERM, signal_handler);
11706 #ifdef HAVE_FEENABLEEXCEPT
11707 /* Only required to enable FP exceptions on platforms where they start off
11708 * disabled; this is not necessary but if it is not done pngvalid will likely
11709 * end up ignoring FP conditions that other platforms fault.
11711 feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
11714 modifier_init(&pm);
11716 /* Preallocate the image buffer, because we know how big it needs to be,
11717 * note that, for testing purposes, it is deliberately mis-aligned by tag
11718 * bytes either side. All rows have an additional five bytes of padding for
11719 * overwrite checking.
11721 store_ensure_image(&pm.this, NULL, 2, TRANSFORM_ROWMAX, TRANSFORM_HEIGHTMAX);
11723 /* Don't give argv[0], it's normally some horrible libtool string: */
11724 cp = safecat(command, sizeof command, cp, "pngvalid");
11726 /* Default to error on warning: */
11727 pm.this.treat_warnings_as_errors = 1;
11729 /* Default assume_16_bit_calculations appropriately; this tells the checking
11730 * code that 16-bit arithmetic is used for 8-bit samples when it would make a
11733 pm.assume_16_bit_calculations = PNG_LIBPNG_VER >= 10700;
11735 /* Currently 16 bit expansion happens at the end of the pipeline, so the
11736 * calculations are done in the input bit depth not the output.
11740 pm.calculations_use_input_precision = 1U;
11742 /* Store the test gammas */
11743 pm.gammas = gammas;
11744 pm.ngammas = ARRAY_SIZE(gammas);
11745 pm.ngamma_tests = 0; /* default to off */
11747 /* Low bit depth gray images don't do well in the gamma tests, until
11748 * this is fixed turn them off for some gamma cases:
11750 # ifdef PNG_WRITE_tRNS_SUPPORTED
11753 pm.test_lbg = PNG_LIBPNG_VER >= 10600;
11754 pm.test_lbg_gamma_threshold = 1;
11755 pm.test_lbg_gamma_transform = PNG_LIBPNG_VER >= 10600;
11756 pm.test_lbg_gamma_sbit = 1;
11757 pm.test_lbg_gamma_composition = PNG_LIBPNG_VER >= 10700;
11759 /* And the test encodings */
11760 pm.encodings = test_encodings;
11761 pm.nencodings = ARRAY_SIZE(test_encodings);
11763 # if PNG_LIBPNG_VER < 10700
11764 pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */
11769 /* The following allows results to pass if they correspond to anything in the
11770 * transformed range [input-.5,input+.5]; this is is required because of the
11771 * way libpng treats the 16_TO_8 flag when building the gamma tables in
11772 * releases up to 1.6.0.
11774 * TODO: review this
11776 pm.use_input_precision_16to8 = 1U;
11777 pm.use_input_precision_sbit = 1U; /* because libpng now rounds sBIT */
11779 /* Some default values (set the behavior for 'make check' here).
11780 * These values simply control the maximum error permitted in the gamma
11781 * transformations. The practical limits for human perception are described
11782 * below (the setting for maxpc16), however for 8 bit encodings it isn't
11783 * possible to meet the accepted capabilities of human vision - i.e. 8 bit
11784 * images can never be good enough, regardless of encoding.
11786 pm.maxout8 = .1; /* Arithmetic error in *encoded* value */
11787 pm.maxabs8 = .00005; /* 1/20000 */
11788 pm.maxcalc8 = 1./255; /* +/-1 in 8 bits for compose errors */
11789 pm.maxpc8 = .499; /* I.e., .499% fractional error */
11790 pm.maxout16 = .499; /* Error in *encoded* value */
11791 pm.maxabs16 = .00005;/* 1/20000 */
11792 pm.maxcalc16 =1./65535;/* +/-1 in 16 bits for compose errors */
11793 # if PNG_LIBPNG_VER < 10700
11794 pm.maxcalcG = 1./((1<<PNG_MAX_GAMMA_8)-1);
11796 pm.maxcalcG = 1./((1<<16)-1);
11799 /* NOTE: this is a reasonable perceptual limit. We assume that humans can
11800 * perceive light level differences of 1% over a 100:1 range, so we need to
11801 * maintain 1 in 10000 accuracy (in linear light space), which is what the
11802 * following guarantees. It also allows significantly higher errors at
11803 * higher 16 bit values, which is important for performance. The actual
11804 * maximum 16 bit error is about +/-1.9 in the fixed point implementation but
11805 * this is only allowed for values >38149 by the following:
11807 pm.maxpc16 = .005; /* I.e., 1/200% - 1/20000 */
11809 /* Now parse the command line options. */
11810 while (--argc >= 1)
11812 int catmore = 0; /* Set if the argument has an argument. */
11814 /* Record each argument for posterity: */
11815 cp = safecat(command, sizeof command, cp, " ");
11816 cp = safecat(command, sizeof command, cp, *++argv);
11818 if (strcmp(*argv, "-v") == 0)
11819 pm.this.verbose = 1;
11821 else if (strcmp(*argv, "-l") == 0)
11824 else if (strcmp(*argv, "-q") == 0)
11825 summary = pm.this.verbose = pm.log = 0;
11827 else if (strcmp(*argv, "-w") == 0 ||
11828 strcmp(*argv, "--strict") == 0)
11829 pm.this.treat_warnings_as_errors = 1; /* NOTE: this is the default! */
11831 else if (strcmp(*argv, "--nostrict") == 0)
11832 pm.this.treat_warnings_as_errors = 0;
11834 else if (strcmp(*argv, "--speed") == 0)
11835 pm.this.speed = 1, pm.ngamma_tests = pm.ngammas, pm.test_standard = 0,
11838 else if (strcmp(*argv, "--memory") == 0)
11841 else if (strcmp(*argv, "--size") == 0)
11844 else if (strcmp(*argv, "--nosize") == 0)
11847 else if (strcmp(*argv, "--standard") == 0)
11848 pm.test_standard = 1;
11850 else if (strcmp(*argv, "--nostandard") == 0)
11851 pm.test_standard = 0;
11853 else if (strcmp(*argv, "--transform") == 0)
11854 pm.test_transform = 1;
11856 else if (strcmp(*argv, "--notransform") == 0)
11857 pm.test_transform = 0;
11859 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
11860 else if (strncmp(*argv, "--transform-disable=",
11861 sizeof "--transform-disable") == 0)
11863 pm.test_transform = 1;
11864 transform_disable(*argv + sizeof "--transform-disable");
11867 else if (strncmp(*argv, "--transform-enable=",
11868 sizeof "--transform-enable") == 0)
11870 pm.test_transform = 1;
11871 transform_enable(*argv + sizeof "--transform-enable");
11873 #endif /* PNG_READ_TRANSFORMS_SUPPORTED */
11875 else if (strcmp(*argv, "--gamma") == 0)
11877 /* Just do two gamma tests here (2.2 and linear) for speed: */
11878 pm.ngamma_tests = 2U;
11879 pm.test_gamma_threshold = 1;
11880 pm.test_gamma_transform = 1;
11881 pm.test_gamma_sbit = 1;
11882 pm.test_gamma_scale16 = 1;
11883 pm.test_gamma_background = 1; /* composition */
11884 pm.test_gamma_alpha_mode = 1;
11887 else if (strcmp(*argv, "--nogamma") == 0)
11888 pm.ngamma_tests = 0;
11890 else if (strcmp(*argv, "--gamma-threshold") == 0)
11891 pm.ngamma_tests = 2U, pm.test_gamma_threshold = 1;
11893 else if (strcmp(*argv, "--nogamma-threshold") == 0)
11894 pm.test_gamma_threshold = 0;
11896 else if (strcmp(*argv, "--gamma-transform") == 0)
11897 pm.ngamma_tests = 2U, pm.test_gamma_transform = 1;
11899 else if (strcmp(*argv, "--nogamma-transform") == 0)
11900 pm.test_gamma_transform = 0;
11902 else if (strcmp(*argv, "--gamma-sbit") == 0)
11903 pm.ngamma_tests = 2U, pm.test_gamma_sbit = 1;
11905 else if (strcmp(*argv, "--nogamma-sbit") == 0)
11906 pm.test_gamma_sbit = 0;
11908 else if (strcmp(*argv, "--gamma-16-to-8") == 0)
11909 pm.ngamma_tests = 2U, pm.test_gamma_scale16 = 1;
11911 else if (strcmp(*argv, "--nogamma-16-to-8") == 0)
11912 pm.test_gamma_scale16 = 0;
11914 else if (strcmp(*argv, "--gamma-background") == 0)
11915 pm.ngamma_tests = 2U, pm.test_gamma_background = 1;
11917 else if (strcmp(*argv, "--nogamma-background") == 0)
11918 pm.test_gamma_background = 0;
11920 else if (strcmp(*argv, "--gamma-alpha-mode") == 0)
11921 pm.ngamma_tests = 2U, pm.test_gamma_alpha_mode = 1;
11923 else if (strcmp(*argv, "--nogamma-alpha-mode") == 0)
11924 pm.test_gamma_alpha_mode = 0;
11926 else if (strcmp(*argv, "--expand16") == 0)
11927 pm.test_gamma_expand16 = 1;
11929 else if (strcmp(*argv, "--noexpand16") == 0)
11930 pm.test_gamma_expand16 = 0;
11932 else if (strcmp(*argv, "--low-depth-gray") == 0)
11933 pm.test_lbg = pm.test_lbg_gamma_threshold =
11934 pm.test_lbg_gamma_transform = pm.test_lbg_gamma_sbit =
11935 pm.test_lbg_gamma_composition = 1;
11937 else if (strcmp(*argv, "--nolow-depth-gray") == 0)
11938 pm.test_lbg = pm.test_lbg_gamma_threshold =
11939 pm.test_lbg_gamma_transform = pm.test_lbg_gamma_sbit =
11940 pm.test_lbg_gamma_composition = 0;
11942 # ifdef PNG_WRITE_tRNS_SUPPORTED
11943 else if (strcmp(*argv, "--tRNS") == 0)
11947 else if (strcmp(*argv, "--notRNS") == 0)
11950 else if (strcmp(*argv, "--more-gammas") == 0)
11951 pm.ngamma_tests = 3U;
11953 else if (strcmp(*argv, "--all-gammas") == 0)
11954 pm.ngamma_tests = pm.ngammas;
11956 else if (strcmp(*argv, "--progressive-read") == 0)
11957 pm.this.progressive = 1;
11959 else if (strcmp(*argv, "--use-update-info") == 0)
11960 ++pm.use_update_info; /* Can call multiple times */
11962 else if (strcmp(*argv, "--interlace") == 0)
11964 # if CAN_WRITE_INTERLACE
11965 pm.interlace_type = PNG_INTERLACE_ADAM7;
11966 # else /* !CAN_WRITE_INTERLACE */
11967 fprintf(stderr, "pngvalid: no write interlace support\n");
11969 # endif /* !CAN_WRITE_INTERLACE */
11972 else if (strcmp(*argv, "--use-input-precision") == 0)
11973 pm.use_input_precision = 1U;
11975 else if (strcmp(*argv, "--use-calculation-precision") == 0)
11976 pm.use_input_precision = 0;
11978 else if (strcmp(*argv, "--calculations-use-input-precision") == 0)
11979 pm.calculations_use_input_precision = 1U;
11981 else if (strcmp(*argv, "--assume-16-bit-calculations") == 0)
11982 pm.assume_16_bit_calculations = 1U;
11984 else if (strcmp(*argv, "--calculations-follow-bit-depth") == 0)
11985 pm.calculations_use_input_precision =
11986 pm.assume_16_bit_calculations = 0;
11988 else if (strcmp(*argv, "--exhaustive") == 0)
11989 pm.test_exhaustive = 1;
11991 else if (argc > 1 && strcmp(*argv, "--sbitlow") == 0)
11992 --argc, pm.sbitlow = (png_byte)atoi(*++argv), catmore = 1;
11994 else if (argc > 1 && strcmp(*argv, "--touch") == 0)
11995 --argc, touch = *++argv, catmore = 1;
11997 else if (argc > 1 && strncmp(*argv, "--max", 5) == 0)
12001 if (strcmp(5+*argv, "abs8") == 0)
12002 pm.maxabs8 = atof(*++argv);
12004 else if (strcmp(5+*argv, "abs16") == 0)
12005 pm.maxabs16 = atof(*++argv);
12007 else if (strcmp(5+*argv, "calc8") == 0)
12008 pm.maxcalc8 = atof(*++argv);
12010 else if (strcmp(5+*argv, "calc16") == 0)
12011 pm.maxcalc16 = atof(*++argv);
12013 else if (strcmp(5+*argv, "out8") == 0)
12014 pm.maxout8 = atof(*++argv);
12016 else if (strcmp(5+*argv, "out16") == 0)
12017 pm.maxout16 = atof(*++argv);
12019 else if (strcmp(5+*argv, "pc8") == 0)
12020 pm.maxpc8 = atof(*++argv);
12022 else if (strcmp(5+*argv, "pc16") == 0)
12023 pm.maxpc16 = atof(*++argv);
12027 fprintf(stderr, "pngvalid: %s: unknown 'max' option\n", *argv);
12034 else if (strcmp(*argv, "--log8") == 0)
12035 --argc, pm.log8 = atof(*++argv), catmore = 1;
12037 else if (strcmp(*argv, "--log16") == 0)
12038 --argc, pm.log16 = atof(*++argv), catmore = 1;
12040 #ifdef PNG_SET_OPTION_SUPPORTED
12041 else if (strncmp(*argv, "--option=", 9) == 0)
12043 /* Syntax of the argument is <option>:{on|off} */
12044 const char *arg = 9+*argv;
12045 unsigned char option=0, setting=0;
12047 #ifdef PNG_ARM_NEON
12048 if (strncmp(arg, "arm-neon:", 9) == 0)
12049 option = PNG_ARM_NEON, arg += 9;
12053 #ifdef PNG_EXTENSIONS
12054 if (strncmp(arg, "extensions:", 11) == 0)
12055 option = PNG_EXTENSIONS, arg += 11;
12059 #ifdef PNG_MAXIMUM_INFLATE_WINDOW
12060 if (strncmp(arg, "max-inflate-window:", 19) == 0)
12061 option = PNG_MAXIMUM_INFLATE_WINDOW, arg += 19;
12066 fprintf(stderr, "pngvalid: %s: %s: unknown option\n", *argv, arg);
12070 if (strcmp(arg, "off") == 0)
12071 setting = PNG_OPTION_OFF;
12073 else if (strcmp(arg, "on") == 0)
12074 setting = PNG_OPTION_ON;
12079 "pngvalid: %s: %s: unknown setting (use 'on' or 'off')\n",
12084 pm.this.options[pm.this.noptions].option = option;
12085 pm.this.options[pm.this.noptions++].setting = setting;
12087 #endif /* PNG_SET_OPTION_SUPPORTED */
12091 fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv);
12095 if (catmore) /* consumed an extra *argv */
12097 cp = safecat(command, sizeof command, cp, " ");
12098 cp = safecat(command, sizeof command, cp, *argv);
12102 /* If pngvalid is run with no arguments default to a reasonable set of the
12105 if (pm.test_standard == 0 && pm.test_size == 0 && pm.test_transform == 0 &&
12106 pm.ngamma_tests == 0)
12108 /* Make this do all the tests done in the test shell scripts with the same
12109 * parameters, where possible. The limitation is that all the progressive
12110 * read and interlace stuff has to be done in separate runs, so only the
12111 * basic 'standard' and 'size' tests are done.
12113 pm.test_standard = 1;
12115 pm.test_transform = 1;
12116 pm.ngamma_tests = 2U;
12119 if (pm.ngamma_tests > 0 &&
12120 pm.test_gamma_threshold == 0 && pm.test_gamma_transform == 0 &&
12121 pm.test_gamma_sbit == 0 && pm.test_gamma_scale16 == 0 &&
12122 pm.test_gamma_background == 0 && pm.test_gamma_alpha_mode == 0)
12124 pm.test_gamma_threshold = 1;
12125 pm.test_gamma_transform = 1;
12126 pm.test_gamma_sbit = 1;
12127 pm.test_gamma_scale16 = 1;
12128 pm.test_gamma_background = 1;
12129 pm.test_gamma_alpha_mode = 1;
12132 else if (pm.ngamma_tests == 0)
12134 /* Nothing to test so turn everything off: */
12135 pm.test_gamma_threshold = 0;
12136 pm.test_gamma_transform = 0;
12137 pm.test_gamma_sbit = 0;
12138 pm.test_gamma_scale16 = 0;
12139 pm.test_gamma_background = 0;
12140 pm.test_gamma_alpha_mode = 0;
12145 /* Make useful base images */
12146 make_transform_images(&pm);
12148 /* Perform the standard and gamma tests. */
12149 if (pm.test_standard)
12151 perform_interlace_macro_validation();
12152 perform_formatting_test(&pm.this);
12153 # ifdef PNG_READ_SUPPORTED
12154 perform_standard_test(&pm);
12156 perform_error_test(&pm);
12159 /* Various oddly sized images: */
12162 make_size_images(&pm.this);
12163 # ifdef PNG_READ_SUPPORTED
12164 perform_size_test(&pm);
12168 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
12169 /* Combinatorial transforms: */
12170 if (pm.test_transform)
12171 perform_transform_test(&pm);
12172 #endif /* PNG_READ_TRANSFORMS_SUPPORTED */
12174 #ifdef PNG_READ_GAMMA_SUPPORTED
12175 if (pm.ngamma_tests > 0)
12176 perform_gamma_test(&pm, summary);
12182 fprintf(stderr, "pngvalid: test aborted (probably failed in cleanup)\n");
12183 if (!pm.this.verbose)
12185 if (pm.this.error[0] != 0)
12186 fprintf(stderr, "pngvalid: first error: %s\n", pm.this.error);
12188 fprintf(stderr, "pngvalid: run with -v to see what happened\n");
12195 printf("%s: %s (%s point arithmetic)\n",
12196 (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
12197 pm.this.nwarnings)) ? "FAIL" : "PASS",
12199 #if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500
12209 printf("Allocated memory statistics (in bytes):\n"
12210 "\tread %lu maximum single, %lu peak, %lu total\n"
12211 "\twrite %lu maximum single, %lu peak, %lu total\n",
12212 (unsigned long)pm.this.read_memory_pool.max_max,
12213 (unsigned long)pm.this.read_memory_pool.max_limit,
12214 (unsigned long)pm.this.read_memory_pool.max_total,
12215 (unsigned long)pm.this.write_memory_pool.max_max,
12216 (unsigned long)pm.this.write_memory_pool.max_limit,
12217 (unsigned long)pm.this.write_memory_pool.max_total);
12220 /* Do this here to provoke memory corruption errors in memory not directly
12221 * allocated by libpng - not a complete test, but better than nothing.
12223 store_delete(&pm.this);
12225 /* Error exit if there are any errors, and maybe if there are any
12228 if (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
12229 pm.this.nwarnings))
12231 if (!pm.this.verbose)
12232 fprintf(stderr, "pngvalid: %s\n", pm.this.error);
12234 fprintf(stderr, "pngvalid: %d errors, %d warnings\n", pm.this.nerrors,
12235 pm.this.nwarnings);
12240 /* Success case. */
12243 FILE *fsuccess = fopen(touch, "wt");
12245 if (fsuccess != NULL)
12248 fprintf(fsuccess, "PNG validation succeeded\n");
12250 error = ferror(fsuccess);
12252 if (fclose(fsuccess) || error)
12254 fprintf(stderr, "%s: write failed\n", touch);
12261 fprintf(stderr, "%s: open failed\n", touch);
12266 /* This is required because some very minimal configurations do not use it:
12271 #else /* write or low level APIs not supported */
12275 "pngvalid: no low level write support in libpng, all tests skipped\n");
12276 /* So the test is skipped: */