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Diffstat (limited to 'Build/source/libs/libpng/libpng-1.6.18/contrib/libtests/pngstest.c')
-rw-r--r-- | Build/source/libs/libpng/libpng-1.6.18/contrib/libtests/pngstest.c | 3853 |
1 files changed, 3853 insertions, 0 deletions
diff --git a/Build/source/libs/libpng/libpng-1.6.18/contrib/libtests/pngstest.c b/Build/source/libs/libpng/libpng-1.6.18/contrib/libtests/pngstest.c new file mode 100644 index 00000000000..5a080b46edd --- /dev/null +++ b/Build/source/libs/libpng/libpng-1.6.18/contrib/libtests/pngstest.c @@ -0,0 +1,3853 @@ +/*- + * pngstest.c + * + * Copyright (c) 2013-2015 John Cunningham Bowler + * + * Last changed in libpng 1.6.18 [July 23, 2015] + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + * Test for the PNG 'simplified' APIs. + */ +#define _ISOC90_SOURCE 1 +#define MALLOC_CHECK_ 2/*glibc facility: turn on debugging*/ + +#include <stddef.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include <errno.h> +#include <ctype.h> +#include <math.h> + +#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H) +# include <config.h> +#endif + +/* Define the following to use this test against your installed libpng, rather + * than the one being built here: + */ +#ifdef PNG_FREESTANDING_TESTS +# include <png.h> +#else +# include "../../png.h" +#endif + +#ifdef PNG_SIMPLIFIED_READ_SUPPORTED /* Else nothing can be done */ +#include "../tools/sRGB.h" + +/* KNOWN ISSUES + * + * These defines switch on alternate algorithms for format conversions to match + * the current libpng implementation; they are set to allow pngstest to pass + * even though libpng is producing answers that are not as correct as they + * should be. + */ +#define ALLOW_UNUSED_GPC 0 + /* If true include unused static GPC functions and declare an external array + * of them to hide the fact that they are unused. This is for development + * use while testing the correct function to use to take into account libpng + * misbehavior, such as using a simple power law to correct sRGB to linear. + */ + +/* The following is to support direct compilation of this file as C++ */ +#ifdef __cplusplus +# define voidcast(type, value) static_cast<type>(value) +# define aligncastconst(type, value) \ + static_cast<type>(static_cast<const void*>(value)) +#else +# define voidcast(type, value) (value) +# define aligncastconst(type, value) ((const void*)(value)) +#endif /* __cplusplus */ + +/* During parallel runs of pngstest each temporary file needs a unique name, + * this is used to permit uniqueness using a command line argument which can be + * up to 22 characters long. + */ +static char tmpf[23] = "TMP"; + +/* Generate random bytes. This uses a boring repeatable algorithm and it + * is implemented here so that it gives the same set of numbers on every + * architecture. It's a linear congruential generator (Knuth or Sedgewick + * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and + * Hill, "The Art of Electronics". + */ +static void +make_random_bytes(png_uint_32* seed, void* pv, size_t size) +{ + png_uint_32 u0 = seed[0], u1 = seed[1]; + png_bytep bytes = voidcast(png_bytep, pv); + + /* There are thirty three bits, the next bit in the sequence is bit-33 XOR + * bit-20. The top 1 bit is in u1, the bottom 32 are in u0. + */ + size_t i; + for (i=0; i<size; ++i) + { + /* First generate 8 new bits then shift them in at the end. */ + png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff; + u1 <<= 8; + u1 |= u0 >> 24; + u0 <<= 8; + u0 |= u; + *bytes++ = (png_byte)u; + } + + seed[0] = u0; + seed[1] = u1; +} + +static void +random_color(png_colorp color) +{ + static png_uint_32 color_seed[2] = { 0x12345678, 0x9abcdef }; + make_random_bytes(color_seed, color, sizeof *color); +} + +/* Math support - neither Cygwin nor Visual Studio have C99 support and we need + * a predictable rounding function, so make one here: + */ +static double +closestinteger(double x) +{ + return floor(x + .5); +} + +/* Cast support: remove GCC whines. */ +static png_byte +u8d(double d) +{ + d = closestinteger(d); + return (png_byte)d; +} + +static png_uint_16 +u16d(double d) +{ + d = closestinteger(d); + return (png_uint_16)d; +} + +/* sRGB support: use exact calculations rounded to the nearest int, see the + * fesetround() call in main(). sRGB_to_d optimizes the 8 to 16-bit conversion. + */ +static double sRGB_to_d[256]; +static double g22_to_d[256]; + +static void +init_sRGB_to_d(void) +{ + int i; + + sRGB_to_d[0] = 0; + for (i=1; i<255; ++i) + sRGB_to_d[i] = linear_from_sRGB(i/255.); + sRGB_to_d[255] = 1; + + g22_to_d[0] = 0; + for (i=1; i<255; ++i) + g22_to_d[i] = pow(i/255., 1/.45455); + g22_to_d[255] = 1; +} + +static png_byte +sRGB(double linear /*range 0.0 .. 1.0*/) +{ + return u8d(255 * sRGB_from_linear(linear)); +} + +static png_byte +isRGB(int fixed_linear) +{ + return sRGB(fixed_linear / 65535.); +} + +#if 0 /* not used */ +static png_byte +unpremultiply(int component, int alpha) +{ + if (alpha <= component) + return 255; /* Arbitrary, but consistent with the libpng code */ + + else if (alpha >= 65535) + return isRGB(component); + + else + return sRGB((double)component / alpha); +} +#endif + +static png_uint_16 +ilinear(int fixed_srgb) +{ + return u16d(65535 * sRGB_to_d[fixed_srgb]); +} + +static png_uint_16 +ilineara(int fixed_srgb, int alpha) +{ + return u16d((257 * alpha) * sRGB_to_d[fixed_srgb]); +} + +static png_uint_16 +ilinear_g22(int fixed_srgb) +{ + return u16d(65535 * g22_to_d[fixed_srgb]); +} + +#if ALLOW_UNUSED_GPC +static png_uint_16 +ilineara_g22(int fixed_srgb, int alpha) +{ + return u16d((257 * alpha) * g22_to_d[fixed_srgb]); +} +#endif + +static double +YfromRGBint(int ir, int ig, int ib) +{ + double r = ir; + double g = ig; + double b = ib; + return YfromRGB(r, g, b); +} + +#if 0 /* unused */ +/* The error that results from using a 2.2 power law in place of the correct + * sRGB transform, given an 8-bit value which might be either sRGB or power-law. + */ +static int +power_law_error8(int value) +{ + if (value > 0 && value < 255) + { + double vd = value / 255.; + double e = fabs( + pow(sRGB_to_d[value], 1/2.2) - sRGB_from_linear(pow(vd, 2.2))); + + /* Always allow an extra 1 here for rounding errors */ + e = 1+floor(255 * e); + return (int)e; + } + + return 0; +} + +static int error_in_sRGB_roundtrip = 56; /* by experiment */ +static int +power_law_error16(int value) +{ + if (value > 0 && value < 65535) + { + /* Round trip the value through an 8-bit representation but using + * non-matching to/from conversions. + */ + double vd = value / 65535.; + double e = fabs( + pow(sRGB_from_linear(vd), 2.2) - linear_from_sRGB(pow(vd, 1/2.2))); + + /* Always allow an extra 1 here for rounding errors */ + e = error_in_sRGB_roundtrip+floor(65535 * e); + return (int)e; + } + + return 0; +} + +static int +compare_8bit(int v1, int v2, int error_limit, int multiple_algorithms) +{ + int e = abs(v1-v2); + int ev1, ev2; + + if (e <= error_limit) + return 1; + + if (!multiple_algorithms) + return 0; + + ev1 = power_law_error8(v1); + if (e <= ev1) + return 1; + + ev2 = power_law_error8(v2); + if (e <= ev2) + return 1; + + return 0; +} + +static int +compare_16bit(int v1, int v2, int error_limit, int multiple_algorithms) +{ + int e = abs(v1-v2); + int ev1, ev2; + + if (e <= error_limit) + return 1; + + /* "multiple_algorithms" in this case means that a color-map has been + * involved somewhere, so we can deduce that the values were forced to 8-bit + * (like the via_linear case for 8-bit.) + */ + if (!multiple_algorithms) + return 0; + + ev1 = power_law_error16(v1); + if (e <= ev1) + return 1; + + ev2 = power_law_error16(v2); + if (e <= ev2) + return 1; + + return 0; +} +#endif /* unused */ + +#define READ_FILE 1 /* else memory */ +#define USE_STDIO 2 /* else use file name */ +#define STRICT 4 /* fail on warnings too */ +#define VERBOSE 8 +#define KEEP_TMPFILES 16 /* else delete temporary files */ +#define KEEP_GOING 32 +#define ACCUMULATE 64 +#define FAST_WRITE 128 +#define sRGB_16BIT 256 + +static void +print_opts(png_uint_32 opts) +{ + if (opts & READ_FILE) + printf(" --file"); + if (opts & USE_STDIO) + printf(" --stdio"); + if (opts & STRICT) + printf(" --strict"); + if (opts & VERBOSE) + printf(" --verbose"); + if (opts & KEEP_TMPFILES) + printf(" --preserve"); + if (opts & KEEP_GOING) + printf(" --keep-going"); + if (opts & ACCUMULATE) + printf(" --accumulate"); + if (!(opts & FAST_WRITE)) /* --fast is currently the default */ + printf(" --slow"); + if (opts & sRGB_16BIT) + printf(" --sRGB-16bit"); +} + +#define FORMAT_NO_CHANGE 0x80000000 /* additional flag */ + +/* A name table for all the formats - defines the format of the '+' arguments to + * pngstest. + */ +#define FORMAT_COUNT 64 +#define FORMAT_MASK 0x3f +static PNG_CONST char * PNG_CONST format_names[FORMAT_COUNT] = +{ + "sRGB-gray", + "sRGB-gray+alpha", + "sRGB-rgb", + "sRGB-rgb+alpha", + "linear-gray", + "linear-gray+alpha", + "linear-rgb", + "linear-rgb+alpha", + + "color-mapped-sRGB-gray", + "color-mapped-sRGB-gray+alpha", + "color-mapped-sRGB-rgb", + "color-mapped-sRGB-rgb+alpha", + "color-mapped-linear-gray", + "color-mapped-linear-gray+alpha", + "color-mapped-linear-rgb", + "color-mapped-linear-rgb+alpha", + + "sRGB-gray", + "sRGB-gray+alpha", + "sRGB-bgr", + "sRGB-bgr+alpha", + "linear-gray", + "linear-gray+alpha", + "linear-bgr", + "linear-bgr+alpha", + + "color-mapped-sRGB-gray", + "color-mapped-sRGB-gray+alpha", + "color-mapped-sRGB-bgr", + "color-mapped-sRGB-bgr+alpha", + "color-mapped-linear-gray", + "color-mapped-linear-gray+alpha", + "color-mapped-linear-bgr", + "color-mapped-linear-bgr+alpha", + + "sRGB-gray", + "alpha+sRGB-gray", + "sRGB-rgb", + "alpha+sRGB-rgb", + "linear-gray", + "alpha+linear-gray", + "linear-rgb", + "alpha+linear-rgb", + + "color-mapped-sRGB-gray", + "color-mapped-alpha+sRGB-gray", + "color-mapped-sRGB-rgb", + "color-mapped-alpha+sRGB-rgb", + "color-mapped-linear-gray", + "color-mapped-alpha+linear-gray", + "color-mapped-linear-rgb", + "color-mapped-alpha+linear-rgb", + + "sRGB-gray", + "alpha+sRGB-gray", + "sRGB-bgr", + "alpha+sRGB-bgr", + "linear-gray", + "alpha+linear-gray", + "linear-bgr", + "alpha+linear-bgr", + + "color-mapped-sRGB-gray", + "color-mapped-alpha+sRGB-gray", + "color-mapped-sRGB-bgr", + "color-mapped-alpha+sRGB-bgr", + "color-mapped-linear-gray", + "color-mapped-alpha+linear-gray", + "color-mapped-linear-bgr", + "color-mapped-alpha+linear-bgr", +}; + +/* Decode an argument to a format number. */ +static png_uint_32 +formatof(const char *arg) +{ + char *ep; + unsigned long format = strtoul(arg, &ep, 0); + + if (ep > arg && *ep == 0 && format < FORMAT_COUNT) + return (png_uint_32)format; + + else for (format=0; format < FORMAT_COUNT; ++format) + { + if (strcmp(format_names[format], arg) == 0) + return (png_uint_32)format; + } + + fprintf(stderr, "pngstest: format name '%s' invalid\n", arg); + return FORMAT_COUNT; +} + +/* Bitset/test functions for formats */ +#define FORMAT_SET_COUNT (FORMAT_COUNT / 32) +typedef struct +{ + png_uint_32 bits[FORMAT_SET_COUNT]; +} +format_list; + +static void format_init(format_list *pf) +{ + int i; + for (i=0; i<FORMAT_SET_COUNT; ++i) + pf->bits[i] = 0; /* All off */ +} + +#if 0 /* currently unused */ +static void format_clear(format_list *pf) +{ + int i; + for (i=0; i<FORMAT_SET_COUNT; ++i) + pf->bits[i] = 0; +} +#endif + +static int format_is_initial(format_list *pf) +{ + int i; + for (i=0; i<FORMAT_SET_COUNT; ++i) + if (pf->bits[i] != 0) + return 0; + + return 1; +} + +static int format_set(format_list *pf, png_uint_32 format) +{ + if (format < FORMAT_COUNT) + return pf->bits[format >> 5] |= ((png_uint_32)1) << (format & 31); + + return 0; +} + +#if 0 /* currently unused */ +static int format_unset(format_list *pf, png_uint_32 format) +{ + if (format < FORMAT_COUNT) + return pf->bits[format >> 5] &= ~((png_uint_32)1) << (format & 31); + + return 0; +} +#endif + +static int format_isset(format_list *pf, png_uint_32 format) +{ + return format < FORMAT_COUNT && + (pf->bits[format >> 5] & (((png_uint_32)1) << (format & 31))) != 0; +} + +static void format_default(format_list *pf, int redundant) +{ + if (redundant) + { + int i; + + /* set everything, including flags that are pointless */ + for (i=0; i<FORMAT_SET_COUNT; ++i) + pf->bits[i] = ~(png_uint_32)0; + } + + else + { + png_uint_32 f; + + for (f=0; f<FORMAT_COUNT; ++f) + { + /* Eliminate redundant and unsupported settings. */ +# ifdef PNG_FORMAT_BGR_SUPPORTED + /* BGR is meaningless if no color: */ + if ((f & PNG_FORMAT_FLAG_COLOR) == 0 && + (f & PNG_FORMAT_FLAG_BGR) != 0) +# else + if ((f & 0x10U/*HACK: fixed value*/) != 0) +# endif + continue; + + /* AFIRST is meaningless if no alpha: */ +# ifdef PNG_FORMAT_AFIRST_SUPPORTED + if ((f & PNG_FORMAT_FLAG_ALPHA) == 0 && + (f & PNG_FORMAT_FLAG_AFIRST) != 0) +# else + if ((f & 0x20U/*HACK: fixed value*/) != 0) +# endif + continue; + + format_set(pf, f); + } + } +} + +/* THE Image STRUCTURE */ +/* The super-class of a png_image, contains the decoded image plus the input + * data necessary to re-read the file with a different format. + */ +typedef struct +{ + png_image image; + png_uint_32 opts; + const char *file_name; + int stride_extra; + FILE *input_file; + png_voidp input_memory; + png_size_t input_memory_size; + png_bytep buffer; + ptrdiff_t stride; + png_size_t bufsize; + png_size_t allocsize; + char tmpfile_name[32]; + png_uint_16 colormap[256*4]; +} +Image; + +/* Initializer: also sets the permitted error limit for 16-bit operations. */ +static void +newimage(Image *image) +{ + memset(image, 0, sizeof *image); +} + +/* Reset the image to be read again - only needs to rewind the FILE* at present. + */ +static void +resetimage(Image *image) +{ + if (image->input_file != NULL) + rewind(image->input_file); +} + +/* Free the image buffer; the buffer is re-used on a re-read, this is just for + * cleanup. + */ +static void +freebuffer(Image *image) +{ + if (image->buffer) free(image->buffer); + image->buffer = NULL; + image->bufsize = 0; + image->allocsize = 0; +} + +/* Delete function; cleans out all the allocated data and the temporary file in + * the image. + */ +static void +freeimage(Image *image) +{ + freebuffer(image); + png_image_free(&image->image); + + if (image->input_file != NULL) + { + fclose(image->input_file); + image->input_file = NULL; + } + + if (image->input_memory != NULL) + { + free(image->input_memory); + image->input_memory = NULL; + image->input_memory_size = 0; + } + + if (image->tmpfile_name[0] != 0 && (image->opts & KEEP_TMPFILES) == 0) + { + (void)remove(image->tmpfile_name); + image->tmpfile_name[0] = 0; + } +} + +/* This is actually a re-initializer; allows an image structure to be re-used by + * freeing everything that relates to an old image. + */ +static void initimage(Image *image, png_uint_32 opts, const char *file_name, + int stride_extra) +{ + freeimage(image); + memset(&image->image, 0, sizeof image->image); + image->opts = opts; + image->file_name = file_name; + image->stride_extra = stride_extra; +} + +/* Make sure the image buffer is big enough; allows re-use of the buffer if the + * image is re-read. + */ +#define BUFFER_INIT8 73 +static void +allocbuffer(Image *image) +{ + png_size_t size = PNG_IMAGE_BUFFER_SIZE(image->image, image->stride); + + if (size+32 > image->bufsize) + { + freebuffer(image); + image->buffer = voidcast(png_bytep, malloc(size+32)); + if (image->buffer == NULL) + { + fflush(stdout); + fprintf(stderr, + "simpletest: out of memory allocating %lu(+32) byte buffer\n", + (unsigned long)size); + exit(1); + } + image->bufsize = size+32; + } + + memset(image->buffer, 95, image->bufsize); + memset(image->buffer+16, BUFFER_INIT8, size); + image->allocsize = size; +} + +/* Make sure 16 bytes match the given byte. */ +static int +check16(png_const_bytep bp, int b) +{ + int i = 16; + + do + if (*bp != b) return 1; + while (--i); + + return 0; +} + +/* Check for overwrite in the image buffer. */ +static void +checkbuffer(Image *image, const char *arg) +{ + if (check16(image->buffer, 95)) + { + fflush(stdout); + fprintf(stderr, "%s: overwrite at start of image buffer\n", arg); + exit(1); + } + + if (check16(image->buffer+16+image->allocsize, 95)) + { + fflush(stdout); + fprintf(stderr, "%s: overwrite at end of image buffer\n", arg); + exit(1); + } +} + +/* ERROR HANDLING */ +/* Log a terminal error, also frees the libpng part of the image if necessary. + */ +static int +logerror(Image *image, const char *a1, const char *a2, const char *a3) +{ + fflush(stdout); + if (image->image.warning_or_error) + fprintf(stderr, "%s%s%s: %s\n", a1, a2, a3, image->image.message); + + else + fprintf(stderr, "%s%s%s\n", a1, a2, a3); + + if (image->image.opaque != NULL) + { + fprintf(stderr, "%s: image opaque pointer non-NULL on error\n", + image->file_name); + png_image_free(&image->image); + } + + return 0; +} + +/* Log an error and close a file (just a utility to do both things in one + * function call.) + */ +static int +logclose(Image *image, FILE *f, const char *name, const char *operation) +{ + int e = errno; + + fclose(f); + return logerror(image, name, operation, strerror(e)); +} + +/* Make sure the png_image has been freed - validates that libpng is doing what + * the spec says and freeing the image. + */ +static int +checkopaque(Image *image) +{ + if (image->image.opaque != NULL) + { + png_image_free(&image->image); + return logerror(image, image->file_name, ": opaque not NULL", ""); + } + + else if (image->image.warning_or_error != 0 && (image->opts & STRICT) != 0) + return logerror(image, image->file_name, " --strict", ""); + + else + return 1; +} + +/* IMAGE COMPARISON/CHECKING */ +/* Compare the pixels of two images, which should be the same but aren't. The + * images must have been checked for a size match. + */ +typedef struct +{ + /* The components, for grayscale images the gray value is in 'g' and if alpha + * is not present 'a' is set to 255 or 65535 according to format. + */ + int r, g, b, a; +} Pixel; + +typedef struct +{ + /* The background as the original sRGB 8-bit value converted to the final + * integer format and as a double precision linear value in the range 0..1 + * for with partially transparent pixels. + */ + int ir, ig, ib; + double dr, dg, db; /* linear r,g,b scaled to 0..1 */ +} Background; + +/* Basic image formats; control the data but not the layout thereof. */ +#define BASE_FORMATS\ + (PNG_FORMAT_FLAG_ALPHA|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_LINEAR) + +/* Read a Pixel from a buffer. The code below stores the correct routine for + * the format in a function pointer, these are the routines: + */ +static void +gp_g8(Pixel *p, png_const_voidp pb) +{ + png_const_bytep pp = voidcast(png_const_bytep, pb); + + p->r = p->g = p->b = pp[0]; + p->a = 255; +} + +static void +gp_ga8(Pixel *p, png_const_voidp pb) +{ + png_const_bytep pp = voidcast(png_const_bytep, pb); + + p->r = p->g = p->b = pp[0]; + p->a = pp[1]; +} + +#ifdef PNG_FORMAT_AFIRST_SUPPORTED +static void +gp_ag8(Pixel *p, png_const_voidp pb) +{ + png_const_bytep pp = voidcast(png_const_bytep, pb); + + p->r = p->g = p->b = pp[1]; + p->a = pp[0]; +} +#endif + +static void +gp_rgb8(Pixel *p, png_const_voidp pb) +{ + png_const_bytep pp = voidcast(png_const_bytep, pb); + + p->r = pp[0]; + p->g = pp[1]; + p->b = pp[2]; + p->a = 255; +} + +#ifdef PNG_FORMAT_BGR_SUPPORTED +static void +gp_bgr8(Pixel *p, png_const_voidp pb) +{ + png_const_bytep pp = voidcast(png_const_bytep, pb); + + p->r = pp[2]; + p->g = pp[1]; + p->b = pp[0]; + p->a = 255; +} +#endif + +static void +gp_rgba8(Pixel *p, png_const_voidp pb) +{ + png_const_bytep pp = voidcast(png_const_bytep, pb); + + p->r = pp[0]; + p->g = pp[1]; + p->b = pp[2]; + p->a = pp[3]; +} + +#ifdef PNG_FORMAT_BGR_SUPPORTED +static void +gp_bgra8(Pixel *p, png_const_voidp pb) +{ + png_const_bytep pp = voidcast(png_const_bytep, pb); + + p->r = pp[2]; + p->g = pp[1]; + p->b = pp[0]; + p->a = pp[3]; +} +#endif + +#ifdef PNG_FORMAT_AFIRST_SUPPORTED +static void +gp_argb8(Pixel *p, png_const_voidp pb) +{ + png_const_bytep pp = voidcast(png_const_bytep, pb); + + p->r = pp[1]; + p->g = pp[2]; + p->b = pp[3]; + p->a = pp[0]; +} +#endif + +#if defined(PNG_FORMAT_AFIRST_SUPPORTED) && defined(PNG_FORMAT_BGR_SUPPORTED) +static void +gp_abgr8(Pixel *p, png_const_voidp pb) +{ + png_const_bytep pp = voidcast(png_const_bytep, pb); + + p->r = pp[3]; + p->g = pp[2]; + p->b = pp[1]; + p->a = pp[0]; +} +#endif + +static void +gp_g16(Pixel *p, png_const_voidp pb) +{ + png_const_uint_16p pp = voidcast(png_const_uint_16p, pb); + + p->r = p->g = p->b = pp[0]; + p->a = 65535; +} + +static void +gp_ga16(Pixel *p, png_const_voidp pb) +{ + png_const_uint_16p pp = voidcast(png_const_uint_16p, pb); + + p->r = p->g = p->b = pp[0]; + p->a = pp[1]; +} + +#ifdef PNG_FORMAT_AFIRST_SUPPORTED +static void +gp_ag16(Pixel *p, png_const_voidp pb) +{ + png_const_uint_16p pp = voidcast(png_const_uint_16p, pb); + + p->r = p->g = p->b = pp[1]; + p->a = pp[0]; +} +#endif + +static void +gp_rgb16(Pixel *p, png_const_voidp pb) +{ + png_const_uint_16p pp = voidcast(png_const_uint_16p, pb); + + p->r = pp[0]; + p->g = pp[1]; + p->b = pp[2]; + p->a = 65535; +} + +#ifdef PNG_FORMAT_BGR_SUPPORTED +static void +gp_bgr16(Pixel *p, png_const_voidp pb) +{ + png_const_uint_16p pp = voidcast(png_const_uint_16p, pb); + + p->r = pp[2]; + p->g = pp[1]; + p->b = pp[0]; + p->a = 65535; +} +#endif + +static void +gp_rgba16(Pixel *p, png_const_voidp pb) +{ + png_const_uint_16p pp = voidcast(png_const_uint_16p, pb); + + p->r = pp[0]; + p->g = pp[1]; + p->b = pp[2]; + p->a = pp[3]; +} + +#ifdef PNG_FORMAT_BGR_SUPPORTED +static void +gp_bgra16(Pixel *p, png_const_voidp pb) +{ + png_const_uint_16p pp = voidcast(png_const_uint_16p, pb); + + p->r = pp[2]; + p->g = pp[1]; + p->b = pp[0]; + p->a = pp[3]; +} +#endif + +#ifdef PNG_FORMAT_AFIRST_SUPPORTED +static void +gp_argb16(Pixel *p, png_const_voidp pb) +{ + png_const_uint_16p pp = voidcast(png_const_uint_16p, pb); + + p->r = pp[1]; + p->g = pp[2]; + p->b = pp[3]; + p->a = pp[0]; +} +#endif + +#if defined(PNG_FORMAT_AFIRST_SUPPORTED) && defined(PNG_FORMAT_BGR_SUPPORTED) +static void +gp_abgr16(Pixel *p, png_const_voidp pb) +{ + png_const_uint_16p pp = voidcast(png_const_uint_16p, pb); + + p->r = pp[3]; + p->g = pp[2]; + p->b = pp[1]; + p->a = pp[0]; +} +#endif + +/* Given a format, return the correct one of the above functions. */ +static void (* +get_pixel(png_uint_32 format))(Pixel *p, png_const_voidp pb) +{ + /* The color-map flag is irrelevant here - the caller of the function + * returned must either pass the buffer or, for a color-mapped image, the + * correct entry in the color-map. + */ + if (format & PNG_FORMAT_FLAG_LINEAR) + { + if (format & PNG_FORMAT_FLAG_COLOR) + { +# ifdef PNG_FORMAT_BGR_SUPPORTED + if (format & PNG_FORMAT_FLAG_BGR) + { + if (format & PNG_FORMAT_FLAG_ALPHA) + { +# ifdef PNG_FORMAT_AFIRST_SUPPORTED + if (format & PNG_FORMAT_FLAG_AFIRST) + return gp_abgr16; + + else +# endif + return gp_bgra16; + } + + else + return gp_bgr16; + } + + else +# endif + { + if (format & PNG_FORMAT_FLAG_ALPHA) + { +# ifdef PNG_FORMAT_AFIRST_SUPPORTED + if (format & PNG_FORMAT_FLAG_AFIRST) + return gp_argb16; + + else +# endif + return gp_rgba16; + } + + else + return gp_rgb16; + } + } + + else + { + if (format & PNG_FORMAT_FLAG_ALPHA) + { +# ifdef PNG_FORMAT_AFIRST_SUPPORTED + if (format & PNG_FORMAT_FLAG_AFIRST) + return gp_ag16; + + else +# endif + return gp_ga16; + } + + else + return gp_g16; + } + } + + else + { + if (format & PNG_FORMAT_FLAG_COLOR) + { +# ifdef PNG_FORMAT_BGR_SUPPORTED + if (format & PNG_FORMAT_FLAG_BGR) + { + if (format & PNG_FORMAT_FLAG_ALPHA) + { +# ifdef PNG_FORMAT_AFIRST_SUPPORTED + if (format & PNG_FORMAT_FLAG_AFIRST) + return gp_abgr8; + + else +# endif + return gp_bgra8; + } + + else + return gp_bgr8; + } + + else +# endif + { + if (format & PNG_FORMAT_FLAG_ALPHA) + { +# ifdef PNG_FORMAT_AFIRST_SUPPORTED + if (format & PNG_FORMAT_FLAG_AFIRST) + return gp_argb8; + + else +# endif + return gp_rgba8; + } + + else + return gp_rgb8; + } + } + + else + { + if (format & PNG_FORMAT_FLAG_ALPHA) + { +# ifdef PNG_FORMAT_AFIRST_SUPPORTED + if (format & PNG_FORMAT_FLAG_AFIRST) + return gp_ag8; + + else +# endif + return gp_ga8; + } + + else + return gp_g8; + } + } +} + +/* Convertion between pixel formats. The code above effectively eliminates the + * component ordering changes leaving three basic changes: + * + * 1) Remove an alpha channel by pre-multiplication or compositing on a + * background color. (Adding an alpha channel is a no-op.) + * + * 2) Remove color by mapping to grayscale. (Grayscale to color is a no-op.) + * + * 3) Convert between 8-bit and 16-bit components. (Both directtions are + * relevant.) + * + * This gives the following base format conversion matrix: + * + * OUT: ----- 8-bit ----- ----- 16-bit ----- + * IN G GA RGB RGBA G GA RGB RGBA + * 8 G . . . . lin lin lin lin + * 8 GA bckg . bckc . pre' pre pre' pre + * 8 RGB g8 g8 . . glin glin lin lin + * 8 RGBA g8b g8 bckc . gpr' gpre pre' pre + * 16 G sRGB sRGB sRGB sRGB . . . . + * 16 GA b16g unpg b16c unpc A . A . + * 16 RGB sG sG sRGB sRGB g16 g16 . . + * 16 RGBA gb16 sGp cb16 sCp g16 g16' A . + * + * 8-bit to 8-bit: + * bckg: composite on gray background + * bckc: composite on color background + * g8: convert sRGB components to sRGB grayscale + * g8b: convert sRGB components to grayscale and composite on gray background + * + * 8-bit to 16-bit: + * lin: make sRGB components linear, alpha := 65535 + * pre: make sRGB components linear and premultiply by alpha (scale alpha) + * pre': as 'pre' but alpha := 65535 + * glin: make sRGB components linear, convert to grayscale, alpha := 65535 + * gpre: make sRGB components grayscale and linear and premultiply by alpha + * gpr': as 'gpre' but alpha := 65535 + * + * 16-bit to 8-bit: + * sRGB: convert linear components to sRGB, alpha := 255 + * unpg: unpremultiply gray component and convert to sRGB (scale alpha) + * unpc: unpremultiply color components and convert to sRGB (scale alpha) + * b16g: composite linear onto gray background and convert the result to sRGB + * b16c: composite linear onto color background and convert the result to sRGB + * sG: convert linear RGB to sRGB grayscale + * sGp: unpremultiply RGB then convert to sRGB grayscale + * sCp: unpremultiply RGB then convert to sRGB + * gb16: composite linear onto background and convert to sRGB grayscale + * (order doesn't matter, the composite and grayscale operations permute) + * cb16: composite linear onto background and convert to sRGB + * + * 16-bit to 16-bit: + * A: set alpha to 65535 + * g16: convert linear RGB to linear grayscale (alpha := 65535) + * g16': as 'g16' but alpha is unchanged + */ +/* Simple copy: */ +static void +gpc_noop(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + out->r = in->r; + out->g = in->g; + out->b = in->b; + out->a = in->a; +} + +#if ALLOW_UNUSED_GPC +static void +gpc_nop8(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + if (in->a == 0) + out->r = out->g = out->b = 255; + + else + { + out->r = in->r; + out->g = in->g; + out->b = in->b; + } + + out->a = in->a; +} +#endif + +#if ALLOW_UNUSED_GPC +static void +gpc_nop6(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + if (in->a == 0) + out->r = out->g = out->b = 65535; + + else + { + out->r = in->r; + out->g = in->g; + out->b = in->b; + } + + out->a = in->a; +} +#endif + +/* 8-bit to 8-bit conversions */ +/* bckg: composite on gray background */ +static void +gpc_bckg(Pixel *out, const Pixel *in, const Background *back) +{ + if (in->a <= 0) + out->r = out->g = out->b = back->ig; + + else if (in->a >= 255) + out->r = out->g = out->b = in->g; + + else + { + double a = in->a / 255.; + + out->r = out->g = out->b = sRGB(sRGB_to_d[in->g] * a + back->dg * (1-a)); + } + + out->a = 255; +} + +/* bckc: composite on color background */ +static void +gpc_bckc(Pixel *out, const Pixel *in, const Background *back) +{ + if (in->a <= 0) + { + out->r = back->ir; + out->g = back->ig; + out->b = back->ib; + } + + else if (in->a >= 255) + { + out->r = in->r; + out->g = in->g; + out->b = in->b; + } + + else + { + double a = in->a / 255.; + + out->r = sRGB(sRGB_to_d[in->r] * a + back->dr * (1-a)); + out->g = sRGB(sRGB_to_d[in->g] * a + back->dg * (1-a)); + out->b = sRGB(sRGB_to_d[in->b] * a + back->db * (1-a)); + } + + out->a = 255; +} + +/* g8: convert sRGB components to sRGB grayscale */ +static void +gpc_g8(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + if (in->r == in->g && in->g == in->b) + out->r = out->g = out->b = in->g; + + else + out->r = out->g = out->b = + sRGB(YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b])); + + out->a = in->a; +} + +/* g8b: convert sRGB components to grayscale and composite on gray background */ +static void +gpc_g8b(Pixel *out, const Pixel *in, const Background *back) +{ + if (in->a <= 0) + out->r = out->g = out->b = back->ig; + + else if (in->a >= 255) + { + if (in->r == in->g && in->g == in->b) + out->r = out->g = out->b = in->g; + + else + out->r = out->g = out->b = sRGB(YfromRGB( + sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b])); + } + + else + { + double a = in->a/255.; + + out->r = out->g = out->b = sRGB(a * YfromRGB(sRGB_to_d[in->r], + sRGB_to_d[in->g], sRGB_to_d[in->b]) + back->dg * (1-a)); + } + + out->a = 255; +} + +/* 8-bit to 16-bit conversions */ +/* lin: make sRGB components linear, alpha := 65535 */ +static void +gpc_lin(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + out->r = ilinear(in->r); + + if (in->g == in->r) + { + out->g = out->r; + + if (in->b == in->r) + out->b = out->r; + + else + out->b = ilinear(in->b); + } + + else + { + out->g = ilinear(in->g); + + if (in->b == in->r) + out->b = out->r; + + else if (in->b == in->g) + out->b = out->g; + + else + out->b = ilinear(in->b); + } + + out->a = 65535; +} + +/* pre: make sRGB components linear and premultiply by alpha (scale alpha) */ +static void +gpc_pre(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + out->r = ilineara(in->r, in->a); + + if (in->g == in->r) + { + out->g = out->r; + + if (in->b == in->r) + out->b = out->r; + + else + out->b = ilineara(in->b, in->a); + } + + else + { + out->g = ilineara(in->g, in->a); + + if (in->b == in->r) + out->b = out->r; + + else if (in->b == in->g) + out->b = out->g; + + else + out->b = ilineara(in->b, in->a); + } + + out->a = in->a * 257; +} + +/* pre': as 'pre' but alpha := 65535 */ +static void +gpc_preq(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + out->r = ilineara(in->r, in->a); + + if (in->g == in->r) + { + out->g = out->r; + + if (in->b == in->r) + out->b = out->r; + + else + out->b = ilineara(in->b, in->a); + } + + else + { + out->g = ilineara(in->g, in->a); + + if (in->b == in->r) + out->b = out->r; + + else if (in->b == in->g) + out->b = out->g; + + else + out->b = ilineara(in->b, in->a); + } + + out->a = 65535; +} + +/* glin: make sRGB components linear, convert to grayscale, alpha := 65535 */ +static void +gpc_glin(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + if (in->r == in->g && in->g == in->b) + out->r = out->g = out->b = ilinear(in->g); + + else + out->r = out->g = out->b = u16d(65535 * + YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b])); + + out->a = 65535; +} + +/* gpre: make sRGB components grayscale and linear and premultiply by alpha */ +static void +gpc_gpre(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + if (in->r == in->g && in->g == in->b) + out->r = out->g = out->b = ilineara(in->g, in->a); + + else + out->r = out->g = out->b = u16d(in->a * 257 * + YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b])); + + out->a = 257 * in->a; +} + +/* gpr': as 'gpre' but alpha := 65535 */ +static void +gpc_gprq(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + if (in->r == in->g && in->g == in->b) + out->r = out->g = out->b = ilineara(in->g, in->a); + + else + out->r = out->g = out->b = u16d(in->a * 257 * + YfromRGB(sRGB_to_d[in->r], sRGB_to_d[in->g], sRGB_to_d[in->b])); + + out->a = 65535; +} + +/* 8-bit to 16-bit conversions for gAMA 45455 encoded values */ +/* Lin: make gAMA 45455 components linear, alpha := 65535 */ +static void +gpc_Lin(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + out->r = ilinear_g22(in->r); + + if (in->g == in->r) + { + out->g = out->r; + + if (in->b == in->r) + out->b = out->r; + + else + out->b = ilinear_g22(in->b); + } + + else + { + out->g = ilinear_g22(in->g); + + if (in->b == in->r) + out->b = out->r; + + else if (in->b == in->g) + out->b = out->g; + + else + out->b = ilinear_g22(in->b); + } + + out->a = 65535; +} + +#if ALLOW_UNUSED_GPC +/* Pre: make gAMA 45455 components linear and premultiply by alpha (scale alpha) + */ +static void +gpc_Pre(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + out->r = ilineara_g22(in->r, in->a); + + if (in->g == in->r) + { + out->g = out->r; + + if (in->b == in->r) + out->b = out->r; + + else + out->b = ilineara_g22(in->b, in->a); + } + + else + { + out->g = ilineara_g22(in->g, in->a); + + if (in->b == in->r) + out->b = out->r; + + else if (in->b == in->g) + out->b = out->g; + + else + out->b = ilineara_g22(in->b, in->a); + } + + out->a = in->a * 257; +} +#endif + +#if ALLOW_UNUSED_GPC +/* Pre': as 'Pre' but alpha := 65535 */ +static void +gpc_Preq(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + out->r = ilineara_g22(in->r, in->a); + + if (in->g == in->r) + { + out->g = out->r; + + if (in->b == in->r) + out->b = out->r; + + else + out->b = ilineara_g22(in->b, in->a); + } + + else + { + out->g = ilineara_g22(in->g, in->a); + + if (in->b == in->r) + out->b = out->r; + + else if (in->b == in->g) + out->b = out->g; + + else + out->b = ilineara_g22(in->b, in->a); + } + + out->a = 65535; +} +#endif + +#if ALLOW_UNUSED_GPC +/* Glin: make gAMA 45455 components linear, convert to grayscale, alpha := 65535 + */ +static void +gpc_Glin(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + if (in->r == in->g && in->g == in->b) + out->r = out->g = out->b = ilinear_g22(in->g); + + else + out->r = out->g = out->b = u16d(65535 * + YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b])); + + out->a = 65535; +} +#endif + +#if ALLOW_UNUSED_GPC +/* Gpre: make gAMA 45455 components grayscale and linear and premultiply by + * alpha. + */ +static void +gpc_Gpre(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + if (in->r == in->g && in->g == in->b) + out->r = out->g = out->b = ilineara_g22(in->g, in->a); + + else + out->r = out->g = out->b = u16d(in->a * 257 * + YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b])); + + out->a = 257 * in->a; +} +#endif + +#if ALLOW_UNUSED_GPC +/* Gpr': as 'Gpre' but alpha := 65535 */ +static void +gpc_Gprq(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + if (in->r == in->g && in->g == in->b) + out->r = out->g = out->b = ilineara_g22(in->g, in->a); + + else + out->r = out->g = out->b = u16d(in->a * 257 * + YfromRGB(g22_to_d[in->r], g22_to_d[in->g], g22_to_d[in->b])); + + out->a = 65535; +} +#endif + +/* 16-bit to 8-bit conversions */ +/* sRGB: convert linear components to sRGB, alpha := 255 */ +static void +gpc_sRGB(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + out->r = isRGB(in->r); + + if (in->g == in->r) + { + out->g = out->r; + + if (in->b == in->r) + out->b = out->r; + + else + out->b = isRGB(in->b); + } + + else + { + out->g = isRGB(in->g); + + if (in->b == in->r) + out->b = out->r; + + else if (in->b == in->g) + out->b = out->g; + + else + out->b = isRGB(in->b); + } + + out->a = 255; +} + +/* unpg: unpremultiply gray component and convert to sRGB (scale alpha) */ +static void +gpc_unpg(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + if (in->a <= 128) + { + out->r = out->g = out->b = 255; + out->a = 0; + } + + else + { + out->r = out->g = out->b = sRGB((double)in->g / in->a); + out->a = u8d(in->a / 257.); + } +} + +/* unpc: unpremultiply color components and convert to sRGB (scale alpha) */ +static void +gpc_unpc(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + if (in->a <= 128) + { + out->r = out->g = out->b = 255; + out->a = 0; + } + + else + { + out->r = sRGB((double)in->r / in->a); + out->g = sRGB((double)in->g / in->a); + out->b = sRGB((double)in->b / in->a); + out->a = u8d(in->a / 257.); + } +} + +/* b16g: composite linear onto gray background and convert the result to sRGB */ +static void +gpc_b16g(Pixel *out, const Pixel *in, const Background *back) +{ + if (in->a <= 0) + out->r = out->g = out->b = back->ig; + + else + { + double a = in->a/65535.; + double a1 = 1-a; + + a /= 65535; + out->r = out->g = out->b = sRGB(in->g * a + back->dg * a1); + } + + out->a = 255; +} + +/* b16c: composite linear onto color background and convert the result to sRGB*/ +static void +gpc_b16c(Pixel *out, const Pixel *in, const Background *back) +{ + if (in->a <= 0) + { + out->r = back->ir; + out->g = back->ig; + out->b = back->ib; + } + + else + { + double a = in->a/65535.; + double a1 = 1-a; + + a /= 65535; + out->r = sRGB(in->r * a + back->dr * a1); + out->g = sRGB(in->g * a + back->dg * a1); + out->b = sRGB(in->b * a + back->db * a1); + } + + out->a = 255; +} + +/* sG: convert linear RGB to sRGB grayscale */ +static void +gpc_sG(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + out->r = out->g = out->b = sRGB(YfromRGBint(in->r, in->g, in->b)/65535); + out->a = 255; +} + +/* sGp: unpremultiply RGB then convert to sRGB grayscale */ +static void +gpc_sGp(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + if (in->a <= 128) + { + out->r = out->g = out->b = 255; + out->a = 0; + } + + else + { + out->r = out->g = out->b = sRGB(YfromRGBint(in->r, in->g, in->b)/in->a); + out->a = u8d(in->a / 257.); + } +} + +/* sCp: unpremultiply RGB then convert to sRGB */ +static void +gpc_sCp(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + + if (in->a <= 128) + { + out->r = out->g = out->b = 255; + out->a = 0; + } + + else + { + out->r = sRGB((double)in->r / in->a); + out->g = sRGB((double)in->g / in->a); + out->b = sRGB((double)in->b / in->a); + out->a = u8d(in->a / 257.); + } +} + +/* gb16: composite linear onto background and convert to sRGB grayscale */ +/* (order doesn't matter, the composite and grayscale operations permute) */ +static void +gpc_gb16(Pixel *out, const Pixel *in, const Background *back) +{ + if (in->a <= 0) + out->r = out->g = out->b = back->ig; + + else if (in->a >= 65535) + out->r = out->g = out->b = isRGB(in->g); + + else + { + double a = in->a / 65535.; + double a1 = 1-a; + + a /= 65535; + out->r = out->g = out->b = sRGB(in->g * a + back->dg * a1); + } + + out->a = 255; +} + +/* cb16: composite linear onto background and convert to sRGB */ +static void +gpc_cb16(Pixel *out, const Pixel *in, const Background *back) +{ + if (in->a <= 0) + { + out->r = back->ir; + out->g = back->ig; + out->b = back->ib; + } + + else if (in->a >= 65535) + { + out->r = isRGB(in->r); + out->g = isRGB(in->g); + out->b = isRGB(in->b); + } + + else + { + double a = in->a / 65535.; + double a1 = 1-a; + + a /= 65535; + out->r = sRGB(in->r * a + back->dr * a1); + out->g = sRGB(in->g * a + back->dg * a1); + out->b = sRGB(in->b * a + back->db * a1); + } + + out->a = 255; +} + +/* 16-bit to 16-bit conversions */ +/* A: set alpha to 65535 */ +static void +gpc_A(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + out->r = in->r; + out->g = in->g; + out->b = in->b; + out->a = 65535; +} + +/* g16: convert linear RGB to linear grayscale (alpha := 65535) */ +static void +gpc_g16(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + out->r = out->g = out->b = u16d(YfromRGBint(in->r, in->g, in->b)); + out->a = 65535; +} + +/* g16': as 'g16' but alpha is unchanged */ +static void +gpc_g16q(Pixel *out, const Pixel *in, const Background *back) +{ + (void)back; + out->r = out->g = out->b = u16d(YfromRGBint(in->r, in->g, in->b)); + out->a = in->a; +} + +#if ALLOW_UNUSED_GPC +/* Unused functions (to hide them from GCC unused function warnings) */ +void (* const gpc_unused[]) + (Pixel *out, const Pixel *in, const Background *back) = +{ + gpc_Pre, gpc_Preq, gpc_Glin, gpc_Gpre, gpc_Gprq, gpc_nop8, gpc_nop6 +}; +#endif + +/* OUT: ----- 8-bit ----- ----- 16-bit ----- + * IN G GA RGB RGBA G GA RGB RGBA + * 8 G . . . . lin lin lin lin + * 8 GA bckg . bckc . pre' pre pre' pre + * 8 RGB g8 g8 . . glin glin lin lin + * 8 RGBA g8b g8 bckc . gpr' gpre pre' pre + * 16 G sRGB sRGB sRGB sRGB . . . . + * 16 GA b16g unpg b16c unpc A . A . + * 16 RGB sG sG sRGB sRGB g16 g16 . . + * 16 RGBA gb16 sGp cb16 sCp g16 g16' A . + * + * The matrix is held in an array indexed thus: + * + * gpc_fn[out_format & BASE_FORMATS][in_format & BASE_FORMATS]; + */ +/* This will produce a compile time error if the FORMAT_FLAG values don't + * match the above matrix! + */ +#if PNG_FORMAT_FLAG_ALPHA == 1 && PNG_FORMAT_FLAG_COLOR == 2 &&\ + PNG_FORMAT_FLAG_LINEAR == 4 +static void (* const gpc_fn[8/*in*/][8/*out*/]) + (Pixel *out, const Pixel *in, const Background *back) = +{ +/*out: G-8 GA-8 RGB-8 RGBA-8 G-16 GA-16 RGB-16 RGBA-16 */ + {gpc_noop,gpc_noop,gpc_noop,gpc_noop, gpc_Lin, gpc_Lin, gpc_Lin, gpc_Lin }, + {gpc_bckg,gpc_noop,gpc_bckc,gpc_noop, gpc_preq,gpc_pre, gpc_preq,gpc_pre }, + {gpc_g8, gpc_g8, gpc_noop,gpc_noop, gpc_glin,gpc_glin,gpc_lin, gpc_lin }, + {gpc_g8b, gpc_g8, gpc_bckc,gpc_noop, gpc_gprq,gpc_gpre,gpc_preq,gpc_pre }, + {gpc_sRGB,gpc_sRGB,gpc_sRGB,gpc_sRGB, gpc_noop,gpc_noop,gpc_noop,gpc_noop}, + {gpc_b16g,gpc_unpg,gpc_b16c,gpc_unpc, gpc_A, gpc_noop,gpc_A, gpc_noop}, + {gpc_sG, gpc_sG, gpc_sRGB,gpc_sRGB, gpc_g16, gpc_g16, gpc_noop,gpc_noop}, + {gpc_gb16,gpc_sGp, gpc_cb16,gpc_sCp, gpc_g16, gpc_g16q,gpc_A, gpc_noop} +}; + +/* The array is repeated for the cases where both the input and output are color + * mapped because then different algorithms are used. + */ +static void (* const gpc_fn_colormapped[8/*in*/][8/*out*/]) + (Pixel *out, const Pixel *in, const Background *back) = +{ +/*out: G-8 GA-8 RGB-8 RGBA-8 G-16 GA-16 RGB-16 RGBA-16 */ + {gpc_noop,gpc_noop,gpc_noop,gpc_noop, gpc_lin, gpc_lin, gpc_lin, gpc_lin }, + {gpc_bckg,gpc_noop,gpc_bckc,gpc_noop, gpc_preq,gpc_pre, gpc_preq,gpc_pre }, + {gpc_g8, gpc_g8, gpc_noop,gpc_noop, gpc_glin,gpc_glin,gpc_lin, gpc_lin }, + {gpc_g8b, gpc_g8, gpc_bckc,gpc_noop, gpc_gprq,gpc_gpre,gpc_preq,gpc_pre }, + {gpc_sRGB,gpc_sRGB,gpc_sRGB,gpc_sRGB, gpc_noop,gpc_noop,gpc_noop,gpc_noop}, + {gpc_b16g,gpc_unpg,gpc_b16c,gpc_unpc, gpc_A, gpc_noop,gpc_A, gpc_noop}, + {gpc_sG, gpc_sG, gpc_sRGB,gpc_sRGB, gpc_g16, gpc_g16, gpc_noop,gpc_noop}, + {gpc_gb16,gpc_sGp, gpc_cb16,gpc_sCp, gpc_g16, gpc_g16q,gpc_A, gpc_noop} +}; + +/* The error arrays record the error in the same matrix; 64 entries, however + * the different algorithms used in libpng for colormap and direct conversions + * mean that four separate matrices are used (for each combination of + * colormapped and direct.) + * + * In some cases the conversion between sRGB formats goes via a linear + * intermediate; an sRGB to linear conversion (as above) is followed by a simple + * linear to sRGB step with no other conversions. This is done by a separate + * error array from an arbitrary 'in' format to one of the four basic outputs + * (since final output is always sRGB not colormapped). + * + * These arrays may be modified if the --accumulate flag is set during the run; + * then instead of logging errors they are simply added in. + * + * The three entries are currently for transparent, partially transparent and + * opaque input pixel values. Notice that alpha should be exact in each case. + * + * Errors in alpha should only occur when converting from a direct format + * to a colormapped format, when alpha is effectively smashed (so large + * errors can occur.) There should be no error in the '0' and 'opaque' + * values. The fourth entry in the array is used for the alpha error (and it + * should always be zero for the 'via linear' case since this is never color + * mapped.) + * + * Mapping to a colormap smashes the colors, it is necessary to have separate + * values for these cases because they are much larger; it is very much + * impossible to obtain a reasonable result, these are held in + * gpc_error_to_colormap. + */ +#if PNG_FORMAT_FLAG_COLORMAP == 8 /* extra check also required */ +/* START MACHINE GENERATED */ +static png_uint_16 gpc_error[16/*in*/][16/*out*/][4/*a*/] = +{ + { /* input: sRGB-gray */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 372, 0 }, { 0, 0, 372, 0 }, { 0, 0, 372, 0 }, { 0, 0, 372, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: sRGB-gray+alpha */ + { 0, 18, 0, 0 }, { 0, 0, 0, 0 }, { 0, 20, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: sRGB-rgb */ + { 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 893, 0 }, { 0, 0, 893, 0 }, { 0, 0, 811, 0 }, { 0, 0, 811, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: sRGB-rgb+alpha */ + { 0, 4, 13, 0 }, { 0, 14, 13, 0 }, { 0, 19, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 832, 764, 0 }, { 0, 832, 764, 0 }, { 0, 897, 788, 0 }, { 0, 897, 788, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: linear-gray */ + { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: linear-gray+alpha */ + { 0, 74, 9, 0 }, { 0, 20, 9, 0 }, { 0, 74, 9, 0 }, { 0, 20, 9, 0 }, + { 0, 0, 0, 0 }, { 0, 1, 0, 0 }, { 0, 0, 0, 0 }, { 0, 1, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: linear-rgb */ + { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, + { 0, 0, 4, 0 }, { 0, 0, 4, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: linear-rgb+alpha */ + { 0, 126, 143, 0 }, { 0, 9, 7, 0 }, { 0, 74, 9, 0 }, { 0, 16, 9, 0 }, + { 0, 4, 4, 0 }, { 0, 5, 4, 0 }, { 0, 0, 0, 0 }, { 0, 1, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: color-mapped-sRGB-gray */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: color-mapped-sRGB-gray+alpha */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: color-mapped-sRGB-rgb */ + { 0, 0, 13, 0 }, { 0, 0, 13, 0 }, { 0, 0, 8, 0 }, { 0, 0, 8, 0 }, + { 0, 0, 673, 0 }, { 0, 0, 673, 0 }, { 0, 0, 674, 0 }, { 0, 0, 674, 0 }, + { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 460, 0 }, { 0, 0, 460, 0 }, { 0, 0, 263, 0 }, { 0, 0, 263, 0 } + }, { /* input: color-mapped-sRGB-rgb+alpha */ + { 0, 6, 8, 0 }, { 0, 7, 8, 0 }, { 0, 75, 8, 0 }, { 0, 9, 8, 0 }, + { 0, 585, 427, 0 }, { 0, 585, 427, 0 }, { 0, 717, 409, 0 }, { 0, 717, 409, 0 }, + { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 13323, 460, 0 }, { 0, 334, 460, 0 }, { 0, 16480, 263, 0 }, { 0, 243, 263, 0 } + }, { /* input: color-mapped-linear-gray */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 282, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: color-mapped-linear-gray+alpha */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 253, 282, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: color-mapped-linear-rgb */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 265, 0 }, { 0, 0, 0, 0 } + }, { /* input: color-mapped-linear-rgb+alpha */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 243, 265, 0 } + } +}; +static png_uint_16 gpc_error_via_linear[16][4/*out*/][4] = +{ + { /* input: sRGB-gray */ + { 0, 0, 7, 0 }, { 0, 0, 7, 0 }, { 0, 0, 7, 0 }, { 0, 0, 7, 0 } + }, { /* input: sRGB-gray+alpha */ + { 0, 15, 15, 0 }, { 0, 186, 15, 0 }, { 0, 15, 15, 0 }, { 0, 186, 15, 0 } + }, { /* input: sRGB-rgb */ + { 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 15, 0 }, { 0, 0, 15, 0 } + }, { /* input: sRGB-rgb+alpha */ + { 0, 12, 14, 0 }, { 0, 180, 14, 0 }, { 0, 14, 15, 0 }, { 0, 186, 15, 0 } + }, { /* input: linear-gray */ + { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 } + }, { /* input: linear-gray+alpha */ + { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 } + }, { /* input: linear-rgb */ + { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 }, { 0, 0, 1, 0 } + }, { /* input: linear-rgb+alpha */ + { 0, 1, 1, 0 }, { 0, 8, 1, 0 }, { 0, 1, 1, 0 }, { 0, 1, 1, 0 } + }, { /* input: color-mapped-sRGB-gray */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: color-mapped-sRGB-gray+alpha */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: color-mapped-sRGB-rgb */ + { 0, 0, 13, 0 }, { 0, 0, 13, 0 }, { 0, 0, 14, 0 }, { 0, 0, 14, 0 } + }, { /* input: color-mapped-sRGB-rgb+alpha */ + { 0, 4, 8, 0 }, { 0, 9, 8, 0 }, { 0, 8, 3, 0 }, { 0, 32, 3, 0 } + }, { /* input: color-mapped-linear-gray */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: color-mapped-linear-gray+alpha */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: color-mapped-linear-rgb */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + }, { /* input: color-mapped-linear-rgb+alpha */ + { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 }, { 0, 0, 0, 0 } + } +}; +static png_uint_16 gpc_error_to_colormap[8/*i*/][8/*o*/][4] = +{ + { /* input: sRGB-gray */ + { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, { 0, 0, 9, 0 }, + { 0, 0, 560, 0 }, { 0, 0, 560, 0 }, { 0, 0, 560, 0 }, { 0, 0, 560, 0 } + }, { /* input: sRGB-gray+alpha */ + { 0, 19, 2, 0 }, { 0, 255, 2, 25 }, { 0, 88, 2, 0 }, { 0, 255, 2, 25 }, + { 0, 1012, 745, 0 }, { 0, 16026, 745, 6425 }, { 0, 1012, 745, 0 }, { 0, 16026, 745, 6425 } + }, { /* input: sRGB-rgb */ + { 0, 0, 19, 0 }, { 0, 0, 19, 0 }, { 0, 0, 25, 0 }, { 0, 0, 25, 0 }, + { 0, 0, 937, 0 }, { 0, 0, 937, 0 }, { 0, 0, 13677, 0 }, { 0, 0, 13677, 0 } + }, { /* input: sRGB-rgb+alpha */ + { 0, 63, 77, 0 }, { 0, 255, 19, 25 }, { 0, 220, 25, 0 }, { 0, 255, 25, 67 }, + { 0, 17534, 18491, 0 }, { 0, 15614, 2824, 6425 }, { 0, 14019, 13677, 0 }, { 0, 48573, 13677, 17219 } + }, { /* input: linear-gray */ + { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, + { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 }, { 0, 0, 18817, 0 } + }, { /* input: linear-gray+alpha */ + { 0, 74, 74, 0 }, { 0, 255, 74, 25 }, { 0, 97, 74, 0 }, { 0, 255, 74, 25 }, + { 0, 18919, 18907, 0 }, { 0, 24549, 18907, 6552 }, { 0, 18919, 18907, 0 }, { 0, 24549, 18907, 6552 } + }, { /* input: linear-rgb */ + { 0, 0, 73, 0 }, { 0, 0, 73, 0 }, { 0, 0, 98, 0 }, { 0, 0, 98, 0 }, + { 0, 0, 18664, 0 }, { 0, 0, 18664, 0 }, { 0, 0, 24998, 0 }, { 0, 0, 24998, 0 } + }, { /* input: linear-rgb+alpha */ + { 0, 181, 196, 0 }, { 0, 255, 61, 25 }, { 206, 187, 98, 0 }, { 0, 255, 98, 67 }, + { 0, 18141, 18137, 0 }, { 0, 17494, 17504, 6553 }, { 0, 24979, 24992, 0 }, { 0, 46509, 24992, 17347 } + } +}; +/* END MACHINE GENERATED */ +#endif /* COLORMAP flag check */ +#endif /* flag checks */ + +typedef struct +{ + /* Basic pixel information: */ + Image* in_image; /* Input image */ + const Image* out_image; /* Output image */ + + /* 'background' is the value passed to the gpc_ routines, it may be NULL if + * it should not be used (*this* program has an error if it crashes as a + * result!) + */ + Background background_color; + const Background* background; + + /* Precalculated values: */ + int in_opaque; /* Value of input alpha that is opaque */ + int is_palette; /* Sample values come from the palette */ + int accumulate; /* Accumlate component errors (don't log) */ + int output_8bit; /* Output is 8 bit (else 16 bit) */ + + void (*in_gp)(Pixel*, png_const_voidp); + void (*out_gp)(Pixel*, png_const_voidp); + + void (*transform)(Pixel *out, const Pixel *in, const Background *back); + /* A function to perform the required transform */ + + void (*from_linear)(Pixel *out, const Pixel *in, const Background *back); + /* For 'via_linear' transforms the final, from linear, step, else NULL */ + + png_uint_16 error[4]; + /* Three error values for transparent, partially transparent and opaque + * input pixels (in turn). + */ + + png_uint_16 *error_ptr; + /* Where these are stored in the static array (for 'accumulate') */ +} +Transform; + +/* Return a 'transform' as above for the given format conversion. */ +static void +transform_from_formats(Transform *result, Image *in_image, + const Image *out_image, png_const_colorp background, int via_linear) +{ + png_uint_32 in_format, out_format; + png_uint_32 in_base, out_base; + + memset(result, 0, sizeof *result); + + /* Store the original images for error messages */ + result->in_image = in_image; + result->out_image = out_image; + + in_format = in_image->image.format; + out_format = out_image->image.format; + + if (in_format & PNG_FORMAT_FLAG_LINEAR) + result->in_opaque = 65535; + else + result->in_opaque = 255; + + result->output_8bit = (out_format & PNG_FORMAT_FLAG_LINEAR) == 0; + + result->is_palette = 0; /* set by caller if required */ + result->accumulate = (in_image->opts & ACCUMULATE) != 0; + + /* The loaders (which need the ordering information) */ + result->in_gp = get_pixel(in_format); + result->out_gp = get_pixel(out_format); + + /* Remove the ordering information: */ + in_format &= BASE_FORMATS | PNG_FORMAT_FLAG_COLORMAP; + in_base = in_format & BASE_FORMATS; + out_format &= BASE_FORMATS | PNG_FORMAT_FLAG_COLORMAP; + out_base = out_format & BASE_FORMATS; + + if (via_linear) + { + /* Check for an error in this program: */ + if (out_format & (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLORMAP)) + { + fprintf(stderr, "internal transform via linear error 0x%x->0x%x\n", + in_format, out_format); + exit(1); + } + + result->transform = gpc_fn[in_base][out_base | PNG_FORMAT_FLAG_LINEAR]; + result->from_linear = gpc_fn[out_base | PNG_FORMAT_FLAG_LINEAR][out_base]; + result->error_ptr = gpc_error_via_linear[in_format][out_format]; + } + + else if (~in_format & out_format & PNG_FORMAT_FLAG_COLORMAP) + { + /* The input is not colormapped but the output is, the errors will + * typically be large (only the grayscale-no-alpha case permits preserving + * even 8-bit values.) + */ + result->transform = gpc_fn[in_base][out_base]; + result->from_linear = NULL; + result->error_ptr = gpc_error_to_colormap[in_base][out_base]; + } + + else + { + /* The caller handles the colormap->pixel value conversion, so the + * transform function just gets a pixel value, however because libpng + * currently contains a different implementation for mapping a colormap if + * both input and output are colormapped we need different conversion + * functions to deal with errors in the libpng implementation. + */ + if (in_format & out_format & PNG_FORMAT_FLAG_COLORMAP) + result->transform = gpc_fn_colormapped[in_base][out_base]; + else + result->transform = gpc_fn[in_base][out_base]; + result->from_linear = NULL; + result->error_ptr = gpc_error[in_format][out_format]; + } + + /* Follow the libpng simplified API rules to work out what to pass to the gpc + * routines as a background value, if one is not required pass NULL so that + * this program crashes in the even of a programming error. + */ + result->background = NULL; /* default: not required */ + + /* Rule 1: background only need be supplied if alpha is to be removed */ + if (in_format & ~out_format & PNG_FORMAT_FLAG_ALPHA) + { + /* The input value is 'NULL' to use the background and (otherwise) an sRGB + * background color (to use a solid color). The code above uses a fixed + * byte value, BUFFER_INIT8, for buffer even for 16-bit output. For + * linear (16-bit) output the sRGB background color is ignored; the + * composition is always on the background (so BUFFER_INIT8 * 257), except + * that for the colormap (i.e. linear colormapped output) black is used. + */ + result->background = &result->background_color; + + if (out_format & PNG_FORMAT_FLAG_LINEAR || via_linear) + { + if (out_format & PNG_FORMAT_FLAG_COLORMAP) + { + result->background_color.ir = + result->background_color.ig = + result->background_color.ib = 0; + result->background_color.dr = + result->background_color.dg = + result->background_color.db = 0; + } + + else + { + result->background_color.ir = + result->background_color.ig = + result->background_color.ib = BUFFER_INIT8 * 257; + result->background_color.dr = + result->background_color.dg = + result->background_color.db = 0; + } + } + + else /* sRGB output */ + { + if (background != NULL) + { + if (out_format & PNG_FORMAT_FLAG_COLOR) + { + result->background_color.ir = background->red; + result->background_color.ig = background->green; + result->background_color.ib = background->blue; + /* TODO: sometimes libpng uses the power law conversion here, how + * to handle this? + */ + result->background_color.dr = sRGB_to_d[background->red]; + result->background_color.dg = sRGB_to_d[background->green]; + result->background_color.db = sRGB_to_d[background->blue]; + } + + else /* grayscale: libpng only looks at 'g' */ + { + result->background_color.ir = + result->background_color.ig = + result->background_color.ib = background->green; + /* TODO: sometimes libpng uses the power law conversion here, how + * to handle this? + */ + result->background_color.dr = + result->background_color.dg = + result->background_color.db = sRGB_to_d[background->green]; + } + } + + else if ((out_format & PNG_FORMAT_FLAG_COLORMAP) == 0) + { + result->background_color.ir = + result->background_color.ig = + result->background_color.ib = BUFFER_INIT8; + /* TODO: sometimes libpng uses the power law conversion here, how + * to handle this? + */ + result->background_color.dr = + result->background_color.dg = + result->background_color.db = sRGB_to_d[BUFFER_INIT8]; + } + + /* Else the output is colormapped and a background color must be + * provided; if pngstest crashes then that is a bug in this program + * (though libpng should png_error as well.) + */ + else + result->background = NULL; + } + } + + if (result->background == NULL) + { + result->background_color.ir = + result->background_color.ig = + result->background_color.ib = -1; /* not used */ + result->background_color.dr = + result->background_color.dg = + result->background_color.db = 1E30; /* not used */ + } + + + /* Copy the error values into the Transform: */ + result->error[0] = result->error_ptr[0]; + result->error[1] = result->error_ptr[1]; + result->error[2] = result->error_ptr[2]; + result->error[3] = result->error_ptr[3]; +} + + +/* Compare two pixels. + * + * OLD error values: +static int error_to_linear = 811; * by experiment * +static int error_to_linear_grayscale = 424; * by experiment * +static int error_to_sRGB = 6; * by experiment * +static int error_to_sRGB_grayscale = 17; * libpng error by calculation + + 2 by experiment * +static int error_in_compose = 2; * by experiment * +static int error_in_premultiply = 1; + * + * The following is *just* the result of a round trip from 8-bit sRGB to linear + * then back to 8-bit sRGB when it is done by libpng. There are two problems: + * + * 1) libpng currently uses a 2.2 power law with no linear segment, this results + * in instability in the low values and even with 16-bit precision sRGB(1) ends + * up mapping to sRGB(0) as a result of rounding in the 16-bit representation. + * This gives an error of 1 in the handling of value 1 only. + * + * 2) libpng currently uses an intermediate 8-bit linear value in gamma + * correction of 8-bit values. This results in many more errors, the worse of + * which is mapping sRGB(14) to sRGB(0). + * + * The general 'error_via_linear' is more complex because of pre-multiplication, + * this compounds the 8-bit errors according to the alpha value of the pixel. + * As a result 256 values are pre-calculated for error_via_linear. + */ +#if 0 +static int error_in_libpng_gamma; +static int error_via_linear[256]; /* Indexed by 8-bit alpha */ + +static void +init_error_via_linear(void) +{ + int alpha; + + error_via_linear[0] = 255; /* transparent pixel */ + + for (alpha=1; alpha<=255; ++alpha) + { + /* 16-bit values less than 128.5 get rounded to 8-bit 0 and so the worst + * case error arises with 16-bit 128.5, work out what sRGB + * (non-associated) value generates 128.5; any value less than this is + * going to map to 0, so the worst error is floor(value). + * + * Note that errors are considerably higher (more than a factor of 2) + * because libpng uses a simple power law for sRGB data at present. + * + * Add .1 for arithmetic errors inside libpng. + */ + double v = floor(255*pow(.5/*(128.5 * 255 / 65535)*/ / alpha, 1/2.2)+.1); + + error_via_linear[alpha] = (int)v; + } + + /* This is actually 14.99, but, despite the closeness to 15, 14 seems to work + * ok in this case. + */ + error_in_libpng_gamma = 14; +} +#endif + +static void +print_pixel(char string[64], const Pixel *pixel, png_uint_32 format) +{ + switch (format & (PNG_FORMAT_FLAG_ALPHA|PNG_FORMAT_FLAG_COLOR)) + { + case 0: + sprintf(string, "%s(%d)", format_names[format], pixel->g); + break; + + case PNG_FORMAT_FLAG_ALPHA: + sprintf(string, "%s(%d,%d)", format_names[format], pixel->g, + pixel->a); + break; + + case PNG_FORMAT_FLAG_COLOR: + sprintf(string, "%s(%d,%d,%d)", format_names[format], + pixel->r, pixel->g, pixel->b); + break; + + case PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA: + sprintf(string, "%s(%d,%d,%d,%d)", format_names[format], + pixel->r, pixel->g, pixel->b, pixel->a); + break; + + default: + sprintf(string, "invalid-format"); + break; + } +} + +static int +logpixel(const Transform *transform, png_uint_32 x, png_uint_32 y, + const Pixel *in, const Pixel *calc, const Pixel *out, const char *reason) +{ + const png_uint_32 in_format = transform->in_image->image.format; + const png_uint_32 out_format = transform->out_image->image.format; + + png_uint_32 back_format = out_format & ~PNG_FORMAT_FLAG_ALPHA; + const char *via_linear = ""; + + char pixel_in[64], pixel_calc[64], pixel_out[64], pixel_loc[64]; + char background_info[100]; + + print_pixel(pixel_in, in, in_format); + print_pixel(pixel_calc, calc, out_format); + print_pixel(pixel_out, out, out_format); + + if (transform->is_palette) + sprintf(pixel_loc, "palette: %lu", (unsigned long)y); + else + sprintf(pixel_loc, "%lu,%lu", (unsigned long)x, (unsigned long)y); + + if (transform->from_linear != NULL) + { + via_linear = " (via linear)"; + /* And as a result the *read* format which did any background processing + * was itself linear, so the background color information is also + * linear. + */ + back_format |= PNG_FORMAT_FLAG_LINEAR; + } + + if (transform->background != NULL) + { + Pixel back; + char pixel_back[64]; + + back.r = transform->background->ir; + back.g = transform->background->ig; + back.b = transform->background->ib; + back.a = -1; /* not used */ + + print_pixel(pixel_back, &back, back_format); + sprintf(background_info, " on background %s", pixel_back); + } + + else + background_info[0] = 0; + + if (transform->in_image->file_name != transform->out_image->file_name) + { + char error_buffer[512]; + sprintf(error_buffer, + "(%s) %s error%s:\n %s%s ->\n %s\n not: %s.\n" + "Use --preserve and examine: ", pixel_loc, reason, via_linear, + pixel_in, background_info, pixel_out, pixel_calc); + return logerror(transform->in_image, transform->in_image->file_name, + error_buffer, transform->out_image->file_name); + } + + else + { + char error_buffer[512]; + sprintf(error_buffer, + "(%s) %s error%s:\n %s%s ->\n %s\n not: %s.\n" + " The error happened when reading the original file with this format.", + pixel_loc, reason, via_linear, pixel_in, background_info, pixel_out, + pixel_calc); + return logerror(transform->in_image, transform->in_image->file_name, + error_buffer, ""); + } +} + +static int +cmppixel(Transform *transform, png_const_voidp in, png_const_voidp out, + png_uint_32 x, png_uint_32 y/*or palette index*/) +{ + int maxerr; + png_const_charp errmsg; + Pixel pixel_in, pixel_calc, pixel_out; + + transform->in_gp(&pixel_in, in); + + if (transform->from_linear == NULL) + transform->transform(&pixel_calc, &pixel_in, transform->background); + + else + { + transform->transform(&pixel_out, &pixel_in, transform->background); + transform->from_linear(&pixel_calc, &pixel_out, NULL); + } + + transform->out_gp(&pixel_out, out); + + /* Eliminate the case where the input and output values match exactly. */ + if (pixel_calc.a == pixel_out.a && pixel_calc.r == pixel_out.r && + pixel_calc.g == pixel_out.g && pixel_calc.b == pixel_out.b) + return 1; + + /* Eliminate the case where the output pixel is transparent and the output + * is 8-bit - any component values are valid. Don't check the input alpha + * here to also skip the 16-bit small alpha cases. + */ + if (transform->output_8bit && pixel_calc.a == 0 && pixel_out.a == 0) + return 1; + + /* Check for alpha errors first; an alpha error can damage the components too + * so avoid spurious checks on components if one is found. + */ + errmsg = NULL; + { + int err_a = abs(pixel_calc.a-pixel_out.a); + + if (err_a > transform->error[3]) + { + /* If accumulating check the components too */ + if (transform->accumulate) + transform->error[3] = (png_uint_16)err_a; + + else + errmsg = "alpha"; + } + } + + /* Now if *either* of the output alphas are 0 but alpha is within tolerance + * eliminate the 8-bit component comparison. + */ + if (errmsg == NULL && transform->output_8bit && + (pixel_calc.a == 0 || pixel_out.a == 0)) + return 1; + + if (errmsg == NULL) /* else just signal an alpha error */ + { + int err_r = abs(pixel_calc.r - pixel_out.r); + int err_g = abs(pixel_calc.g - pixel_out.g); + int err_b = abs(pixel_calc.b - pixel_out.b); + int limit; + + if ((err_r | err_g | err_b) == 0) + return 1; /* exact match */ + + /* Mismatch on a component, check the input alpha */ + if (pixel_in.a >= transform->in_opaque) + { + errmsg = "opaque component"; + limit = 2; /* opaque */ + } + + else if (pixel_in.a > 0) + { + errmsg = "alpha component"; + limit = 1; /* partially transparent */ + } + + else + { + errmsg = "transparent component (background)"; + limit = 0; /* transparent */ + } + + maxerr = err_r; + if (maxerr < err_g) maxerr = err_g; + if (maxerr < err_b) maxerr = err_b; + + if (maxerr <= transform->error[limit]) + return 1; /* within the error limits */ + + /* Handle a component mis-match; log it, just return an error code, or + * accumulate it. + */ + if (transform->accumulate) + { + transform->error[limit] = (png_uint_16)maxerr; + return 1; /* to cause the caller to keep going */ + } + } + + /* Failure to match and not accumulating, so the error must be logged. */ + return logpixel(transform, x, y, &pixel_in, &pixel_calc, &pixel_out, errmsg); +} + +static png_byte +component_loc(png_byte loc[4], png_uint_32 format) +{ + /* Given a format return the number of channels and the location of + * each channel. + * + * The mask 'loc' contains the component offset of the channels in the + * following order. Note that if 'format' is grayscale the entries 1-3 must + * all contain the location of the gray channel. + * + * 0: alpha + * 1: red or gray + * 2: green or gray + * 3: blue or gray + */ + png_byte channels; + + if (format & PNG_FORMAT_FLAG_COLOR) + { + channels = 3; + + loc[2] = 1; + +# ifdef PNG_FORMAT_BGR_SUPPORTED + if (format & PNG_FORMAT_FLAG_BGR) + { + loc[1] = 2; + loc[3] = 0; + } + + else +# endif + { + loc[1] = 0; + loc[3] = 2; + } + } + + else + { + channels = 1; + loc[1] = loc[2] = loc[3] = 0; + } + + if (format & PNG_FORMAT_FLAG_ALPHA) + { +# ifdef PNG_FORMAT_AFIRST_SUPPORTED + if (format & PNG_FORMAT_FLAG_AFIRST) + { + loc[0] = 0; + ++loc[1]; + ++loc[2]; + ++loc[3]; + } + + else +# endif + loc[0] = channels; + + ++channels; + } + + else + loc[0] = 4; /* not present */ + + return channels; +} + +/* Compare two images, the original 'a', which was written out then read back in + * to * give image 'b'. The formats may have been changed. + */ +static int +compare_two_images(Image *a, Image *b, int via_linear, + png_const_colorp background) +{ + ptrdiff_t stridea = a->stride; + ptrdiff_t strideb = b->stride; + png_const_bytep rowa = a->buffer+16; + png_const_bytep rowb = b->buffer+16; + const png_uint_32 width = a->image.width; + const png_uint_32 height = a->image.height; + const png_uint_32 formata = a->image.format; + const png_uint_32 formatb = b->image.format; + const unsigned int a_sample = PNG_IMAGE_SAMPLE_SIZE(formata); + const unsigned int b_sample = PNG_IMAGE_SAMPLE_SIZE(formatb); + int alpha_added, alpha_removed; + int bchannels; + int btoa[4]; + png_uint_32 y; + Transform tr; + + /* This should never happen: */ + if (width != b->image.width || height != b->image.height) + return logerror(a, a->file_name, ": width x height changed: ", + b->file_name); + + /* Set up the background and the transform */ + transform_from_formats(&tr, a, b, background, via_linear); + + /* Find the first row and inter-row space. */ + if (!(formata & PNG_FORMAT_FLAG_COLORMAP) && + (formata & PNG_FORMAT_FLAG_LINEAR)) + stridea *= 2; + + if (!(formatb & PNG_FORMAT_FLAG_COLORMAP) && + (formatb & PNG_FORMAT_FLAG_LINEAR)) + strideb *= 2; + + if (stridea < 0) rowa += (height-1) * (-stridea); + if (strideb < 0) rowb += (height-1) * (-strideb); + + /* First shortcut the two colormap case by comparing the image data; if it + * matches then we expect the colormaps to match, although this is not + * absolutely necessary for an image match. If the colormaps fail to match + * then there is a problem in libpng. + */ + if (formata & formatb & PNG_FORMAT_FLAG_COLORMAP) + { + /* Only check colormap entries that actually exist; */ + png_const_bytep ppa, ppb; + int match; + png_byte in_use[256], amax = 0, bmax = 0; + + memset(in_use, 0, sizeof in_use); + + ppa = rowa; + ppb = rowb; + + /* Do this the slow way to accumulate the 'in_use' flags, don't break out + * of the loop until the end; this validates the color-mapped data to + * ensure all pixels are valid color-map indexes. + */ + for (y=0, match=1; y<height && match; ++y, ppa += stridea, ppb += strideb) + { + png_uint_32 x; + + for (x=0; x<width; ++x) + { + png_byte bval = ppb[x]; + png_byte aval = ppa[x]; + + if (bval > bmax) + bmax = bval; + + if (bval != aval) + match = 0; + + in_use[aval] = 1; + if (aval > amax) + amax = aval; + } + } + + /* If the buffers match then the colormaps must too. */ + if (match) + { + /* Do the color-maps match, entry by entry? Only check the 'in_use' + * entries. An error here should be logged as a color-map error. + */ + png_const_bytep a_cmap = (png_const_bytep)a->colormap; + png_const_bytep b_cmap = (png_const_bytep)b->colormap; + int result = 1; /* match by default */ + + /* This is used in logpixel to get the error message correct. */ + tr.is_palette = 1; + + for (y=0; y<256; ++y, a_cmap += a_sample, b_cmap += b_sample) + if (in_use[y]) + { + /* The colormap entries should be valid, but because libpng doesn't + * do any checking at present the original image may contain invalid + * pixel values. These cause an error here (at present) unless + * accumulating errors in which case the program just ignores them. + */ + if (y >= a->image.colormap_entries) + { + if ((a->opts & ACCUMULATE) == 0) + { + char pindex[9]; + sprintf(pindex, "%lu[%lu]", (unsigned long)y, + (unsigned long)a->image.colormap_entries); + logerror(a, a->file_name, ": bad pixel index: ", pindex); + } + result = 0; + } + + else if (y >= b->image.colormap_entries) + { + if ((b->opts & ACCUMULATE) == 0) + { + char pindex[9]; + sprintf(pindex, "%lu[%lu]", (unsigned long)y, + (unsigned long)b->image.colormap_entries); + logerror(b, b->file_name, ": bad pixel index: ", pindex); + } + result = 0; + } + + /* All the mismatches are logged here; there can only be 256! */ + else if (!cmppixel(&tr, a_cmap, b_cmap, 0, y)) + result = 0; + } + + /* If reqested copy the error values back from the Transform. */ + if (a->opts & ACCUMULATE) + { + tr.error_ptr[0] = tr.error[0]; + tr.error_ptr[1] = tr.error[1]; + tr.error_ptr[2] = tr.error[2]; + tr.error_ptr[3] = tr.error[3]; + result = 1; /* force a continue */ + } + + return result; + } + + /* else the image buffers don't match pixel-wise so compare sample values + * instead, but first validate that the pixel indexes are in range (but + * only if not accumulating, when the error is ignored.) + */ + else if ((a->opts & ACCUMULATE) == 0) + { + /* Check the original image first, + * TODO: deal with input images with bad pixel values? + */ + if (amax >= a->image.colormap_entries) + { + char pindex[9]; + sprintf(pindex, "%d[%lu]", amax, + (unsigned long)a->image.colormap_entries); + return logerror(a, a->file_name, ": bad pixel index: ", pindex); + } + + else if (bmax >= b->image.colormap_entries) + { + char pindex[9]; + sprintf(pindex, "%d[%lu]", bmax, + (unsigned long)b->image.colormap_entries); + return logerror(b, b->file_name, ": bad pixel index: ", pindex); + } + } + } + + /* We can directly compare pixel values without the need to use the read + * or transform support (i.e. a memory compare) if: + * + * 1) The bit depth has not changed. + * 2) RGB to grayscale has not been done (the reverse is ok; we just compare + * the three RGB values to the original grayscale.) + * 3) An alpha channel has not been removed from an 8-bit format, or the + * 8-bit alpha value of the pixel was 255 (opaque). + * + * If an alpha channel has been *added* then it must have the relevant opaque + * value (255 or 65535). + * + * The fist two the tests (in the order given above) (using the boolean + * equivalence !a && !b == !(a || b)) + */ + if (!(((formata ^ formatb) & PNG_FORMAT_FLAG_LINEAR) | + (formata & (formatb ^ PNG_FORMAT_FLAG_COLOR) & PNG_FORMAT_FLAG_COLOR))) + { + /* Was an alpha channel changed? */ + const png_uint_32 alpha_changed = (formata ^ formatb) & + PNG_FORMAT_FLAG_ALPHA; + + /* Was an alpha channel removed? (The third test.) If so the direct + * comparison is only possible if the input alpha is opaque. + */ + alpha_removed = (formata & alpha_changed) != 0; + + /* Was an alpha channel added? */ + alpha_added = (formatb & alpha_changed) != 0; + + /* The channels may have been moved between input and output, this finds + * out how, recording the result in the btoa array, which says where in + * 'a' to find each channel of 'b'. If alpha was added then btoa[alpha] + * ends up as 4 (and is not used.) + */ + { + int i; + png_byte aloc[4]; + png_byte bloc[4]; + + /* The following are used only if the formats match, except that + * 'bchannels' is a flag for matching formats. btoa[x] says, for each + * channel in b, where to find the corresponding value in a, for the + * bchannels. achannels may be different for a gray to rgb transform + * (a will be 1 or 2, b will be 3 or 4 channels.) + */ + (void)component_loc(aloc, formata); + bchannels = component_loc(bloc, formatb); + + /* Hence the btoa array. */ + for (i=0; i<4; ++i) if (bloc[i] < 4) + btoa[bloc[i]] = aloc[i]; /* may be '4' for alpha */ + + if (alpha_added) + alpha_added = bloc[0]; /* location of alpha channel in image b */ + + else + alpha_added = 4; /* Won't match an image b channel */ + + if (alpha_removed) + alpha_removed = aloc[0]; /* location of alpha channel in image a */ + + else + alpha_removed = 4; + } + } + + else + { + /* Direct compare is not possible, cancel out all the corresponding local + * variables. + */ + bchannels = 0; + alpha_removed = alpha_added = 4; + btoa[3] = btoa[2] = btoa[1] = btoa[0] = 4; /* 4 == not present */ + } + + for (y=0; y<height; ++y, rowa += stridea, rowb += strideb) + { + png_const_bytep ppa, ppb; + png_uint_32 x; + + for (x=0, ppa=rowa, ppb=rowb; x<width; ++x) + { + png_const_bytep psa, psb; + + if (formata & PNG_FORMAT_FLAG_COLORMAP) + psa = (png_const_bytep)a->colormap + a_sample * *ppa++; + else + psa = ppa, ppa += a_sample; + + if (formatb & PNG_FORMAT_FLAG_COLORMAP) + psb = (png_const_bytep)b->colormap + b_sample * *ppb++; + else + psb = ppb, ppb += b_sample; + + /* Do the fast test if possible. */ + if (bchannels) + { + /* Check each 'b' channel against either the corresponding 'a' + * channel or the opaque alpha value, as appropriate. If + * alpha_removed value is set (not 4) then also do this only if the + * 'a' alpha channel (alpha_removed) is opaque; only relevant for + * the 8-bit case. + */ + if (formatb & PNG_FORMAT_FLAG_LINEAR) /* 16-bit checks */ + { + png_const_uint_16p pua = aligncastconst(png_const_uint_16p, psa); + png_const_uint_16p pub = aligncastconst(png_const_uint_16p, psb); + + switch (bchannels) + { + case 4: + if (pua[btoa[3]] != pub[3]) break; + case 3: + if (pua[btoa[2]] != pub[2]) break; + case 2: + if (pua[btoa[1]] != pub[1]) break; + case 1: + if (pua[btoa[0]] != pub[0]) break; + if (alpha_added != 4 && pub[alpha_added] != 65535) break; + continue; /* x loop */ + default: + break; /* impossible */ + } + } + + else if (alpha_removed == 4 || psa[alpha_removed] == 255) + { + switch (bchannels) + { + case 4: + if (psa[btoa[3]] != psb[3]) break; + case 3: + if (psa[btoa[2]] != psb[2]) break; + case 2: + if (psa[btoa[1]] != psb[1]) break; + case 1: + if (psa[btoa[0]] != psb[0]) break; + if (alpha_added != 4 && psb[alpha_added] != 255) break; + continue; /* x loop */ + default: + break; /* impossible */ + } + } + } + + /* If we get to here the fast match failed; do the slow match for this + * pixel. + */ + if (!cmppixel(&tr, psa, psb, x, y) && (a->opts & KEEP_GOING) == 0) + return 0; /* error case */ + } + } + + /* If reqested copy the error values back from the Transform. */ + if (a->opts & ACCUMULATE) + { + tr.error_ptr[0] = tr.error[0]; + tr.error_ptr[1] = tr.error[1]; + tr.error_ptr[2] = tr.error[2]; + tr.error_ptr[3] = tr.error[3]; + } + + return 1; +} + +/* Read the file; how the read gets done depends on which of input_file and + * input_memory have been set. + */ +static int +read_file(Image *image, png_uint_32 format, png_const_colorp background) +{ + memset(&image->image, 0, sizeof image->image); + image->image.version = PNG_IMAGE_VERSION; + + if (image->input_memory != NULL) + { + if (!png_image_begin_read_from_memory(&image->image, image->input_memory, + image->input_memory_size)) + return logerror(image, "memory init: ", image->file_name, ""); + } + +# ifdef PNG_STDIO_SUPPORTED + else if (image->input_file != NULL) + { + if (!png_image_begin_read_from_stdio(&image->image, image->input_file)) + return logerror(image, "stdio init: ", image->file_name, ""); + } + + else + { + if (!png_image_begin_read_from_file(&image->image, image->file_name)) + return logerror(image, "file init: ", image->file_name, ""); + } +# else + else + { + return logerror(image, "unsupported file/stdio init: ", + image->file_name, ""); + } +# endif + + /* This must be set after the begin_read call: */ + if (image->opts & sRGB_16BIT) + image->image.flags |= PNG_IMAGE_FLAG_16BIT_sRGB; + + /* Have an initialized image with all the data we need plus, maybe, an + * allocated file (myfile) or buffer (mybuffer) that need to be freed. + */ + { + int result; + png_uint_32 image_format; + + /* Print both original and output formats. */ + image_format = image->image.format; + + if (image->opts & VERBOSE) + { + printf("%s %lu x %lu %s -> %s", image->file_name, + (unsigned long)image->image.width, + (unsigned long)image->image.height, + format_names[image_format & FORMAT_MASK], + (format & FORMAT_NO_CHANGE) != 0 || image->image.format == format + ? "no change" : format_names[format & FORMAT_MASK]); + + if (background != NULL) + printf(" background(%d,%d,%d)\n", background->red, + background->green, background->blue); + else + printf("\n"); + + fflush(stdout); + } + + /* 'NO_CHANGE' combined with the color-map flag forces the base format + * flags to be set on read to ensure that the original representation is + * not lost in the pass through a colormap format. + */ + if ((format & FORMAT_NO_CHANGE) != 0) + { + if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0 && + (image_format & PNG_FORMAT_FLAG_COLORMAP) != 0) + format = (image_format & ~BASE_FORMATS) | (format & BASE_FORMATS); + + else + format = image_format; + } + + image->image.format = format; + + image->stride = PNG_IMAGE_ROW_STRIDE(image->image) + image->stride_extra; + allocbuffer(image); + + result = png_image_finish_read(&image->image, background, + image->buffer+16, (png_int_32)image->stride, image->colormap); + + checkbuffer(image, image->file_name); + + if (result) + return checkopaque(image); + + else + return logerror(image, image->file_name, ": image read failed", ""); + } +} + +/* Reads from a filename, which must be in image->file_name, but uses + * image->opts to choose the method. The file is always read in its native + * format (the one the simplified API suggests). + */ +static int +read_one_file(Image *image) +{ + if (!(image->opts & READ_FILE) || (image->opts & USE_STDIO)) + { + /* memory or stdio. */ + FILE *f = fopen(image->file_name, "rb"); + + if (f != NULL) + { + if (image->opts & READ_FILE) + image->input_file = f; + + else /* memory */ + { + if (fseek(f, 0, SEEK_END) == 0) + { + long int cb = ftell(f); + + if (cb > 0) + { +#ifndef __COVERITY__ + if ((unsigned long int)cb <= (size_t)~(size_t)0) +#endif + { + png_bytep b = voidcast(png_bytep, malloc((size_t)cb)); + + if (b != NULL) + { + rewind(f); + + if (fread(b, (size_t)cb, 1, f) == 1) + { + fclose(f); + image->input_memory_size = cb; + image->input_memory = b; + } + + else + { + free(b); + return logclose(image, f, image->file_name, + ": read failed: "); + } + } + + else + return logclose(image, f, image->file_name, + ": out of memory: "); + } + + else + return logclose(image, f, image->file_name, + ": file too big for this architecture: "); + /* cb is the length of the file as a (long) and + * this is greater than the maximum amount of + * memory that can be requested from malloc. + */ + } + + else if (cb == 0) + return logclose(image, f, image->file_name, + ": zero length: "); + + else + return logclose(image, f, image->file_name, + ": tell failed: "); + } + + else + return logclose(image, f, image->file_name, ": seek failed: "); + } + } + + else + return logerror(image, image->file_name, ": open failed: ", + strerror(errno)); + } + + return read_file(image, FORMAT_NO_CHANGE, NULL); +} + +#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED +static int +write_one_file(Image *output, Image *image, int convert_to_8bit) +{ + if (image->opts & FAST_WRITE) + image->image.flags |= PNG_IMAGE_FLAG_FAST; + + if (image->opts & USE_STDIO) + { +#ifndef PNG_USE_MKSTEMP + FILE *f = tmpfile(); +#else + /* Experimental. Coverity says tmpfile() is insecure because it + * generates predictable names. + * + * It is possible to satisfy Coverity by using mkstemp(); however, + * any platform supporting mkstemp() undoubtedly has a secure tmpfile() + * implementation as well, and doesn't need the fix. Note that + * the fix won't work on platforms that don't support mkstemp(). + * + * https://www.securecoding.cert.org/confluence/display/c/ + * FIO21-C.+Do+not+create+temporary+files+in+shared+directories + * says that most historic implementations of tmpfile() provide + * only a limited number of possible temporary file names + * (usually 26) before file names are recycled. That article also + * provides a secure solution that unfortunately depends upon mkstemp(). + */ + char tmpfile[] = "pngstest-XXXXXX"; + int filedes; + FILE *f; + umask(0177); + filedes = mkstemp(tmpfile); + if (filedes < 0) + f = NULL; + else + { + f = fdopen(filedes,"w+"); + /* Hide the filename immediately and ensure that the file does + * not exist after the program ends + */ + (void) unlink(tmpfile); + } +#endif + + if (f != NULL) + { + if (png_image_write_to_stdio(&image->image, f, convert_to_8bit, + image->buffer+16, (png_int_32)image->stride, image->colormap)) + { + if (fflush(f) == 0) + { + rewind(f); + initimage(output, image->opts, "tmpfile", image->stride_extra); + output->input_file = f; + if (!checkopaque(image)) + return 0; + } + + else + return logclose(image, f, "tmpfile", ": flush: "); + } + + else + { + fclose(f); + return logerror(image, "tmpfile", ": write failed", ""); + } + } + + else + return logerror(image, "tmpfile", ": open: ", strerror(errno)); + } + + else + { + static int counter = 0; + char name[32]; + + sprintf(name, "%s%d.png", tmpf, ++counter); + + if (png_image_write_to_file(&image->image, name, convert_to_8bit, + image->buffer+16, (png_int_32)image->stride, image->colormap)) + { + initimage(output, image->opts, output->tmpfile_name, + image->stride_extra); + /* Afterwards, or freeimage will delete it! */ + strcpy(output->tmpfile_name, name); + + if (!checkopaque(image)) + return 0; + } + + else + return logerror(image, name, ": write failed", ""); + } + + /* 'output' has an initialized temporary image, read this back in and compare + * this against the original: there should be no change since the original + * format was written unmodified unless 'convert_to_8bit' was specified. + * However, if the original image was color-mapped, a simple read will zap + * the linear, color and maybe alpha flags, this will cause spurious failures + * under some circumstances. + */ + if (read_file(output, image->image.format | FORMAT_NO_CHANGE, NULL)) + { + png_uint_32 original_format = image->image.format; + + if (convert_to_8bit) + original_format &= ~PNG_FORMAT_FLAG_LINEAR; + + if ((output->image.format & BASE_FORMATS) != + (original_format & BASE_FORMATS)) + return logerror(image, image->file_name, ": format changed on read: ", + output->file_name); + + return compare_two_images(image, output, 0/*via linear*/, NULL); + } + + else + return logerror(output, output->tmpfile_name, + ": read of new file failed", ""); +} +#endif + +static int +testimage(Image *image, png_uint_32 opts, format_list *pf) +{ + int result; + Image copy; + + /* Copy the original data, stealing it from 'image' */ + checkopaque(image); + copy = *image; + + copy.opts = opts; + copy.buffer = NULL; + copy.bufsize = 0; + copy.allocsize = 0; + + image->input_file = NULL; + image->input_memory = NULL; + image->input_memory_size = 0; + image->tmpfile_name[0] = 0; + + { + png_uint_32 counter; + Image output; + + newimage(&output); + + result = 1; + + /* Use the low bit of 'counter' to indicate whether or not to do alpha + * removal with a background color or by composting onto the image; this + * step gets skipped if it isn't relevant + */ + for (counter=0; counter<2*FORMAT_COUNT; ++counter) + if (format_isset(pf, counter >> 1)) + { + png_uint_32 format = counter >> 1; + + png_color background_color; + png_colorp background = NULL; + + /* If there is a format change that removes the alpha channel then + * the background is relevant. If the output is 8-bit color-mapped + * then a background color *must* be provided, otherwise there are + * two tests to do - one with a color, the other with NULL. The + * NULL test happens second. + */ + if ((counter & 1) == 0) + { + if ((format & PNG_FORMAT_FLAG_ALPHA) == 0 && + (image->image.format & PNG_FORMAT_FLAG_ALPHA) != 0) + { + /* Alpha/transparency will be removed, the background is + * relevant: make it a color the first time + */ + random_color(&background_color); + background = &background_color; + + /* BUT if the output is to a color-mapped 8-bit format then + * the background must always be a color, so increment 'counter' + * to skip the NULL test. + */ + if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0 && + (format & PNG_FORMAT_FLAG_LINEAR) == 0) + ++counter; + } + + /* Otherwise an alpha channel is not being eliminated, just leave + * background NULL and skip the (counter & 1) NULL test. + */ + else + ++counter; + } + /* else just use NULL for background */ + + resetimage(©); + copy.opts = opts; /* in case read_file needs to change it */ + + result = read_file(©, format, background); + if (!result) + break; + + /* Make sure the file just read matches the original file. */ + result = compare_two_images(image, ©, 0/*via linear*/, background); + if (!result) + break; + +# ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED + /* Write the *copy* just made to a new file to make sure the write + * side works ok. Check the conversion to sRGB if the copy is + * linear. + */ + output.opts = opts; + result = write_one_file(&output, ©, 0/*convert to 8bit*/); + if (!result) + break; + + /* Validate against the original too; the background is needed here + * as well so that compare_two_images knows what color was used. + */ + result = compare_two_images(image, &output, 0, background); + if (!result) + break; + + if ((format & PNG_FORMAT_FLAG_LINEAR) != 0 && + (format & PNG_FORMAT_FLAG_COLORMAP) == 0) + { + /* 'output' is linear, convert to the corresponding sRGB format. + */ + output.opts = opts; + result = write_one_file(&output, ©, 1/*convert to 8bit*/); + if (!result) + break; + + /* This may involve a conversion via linear; in the ideal world + * this would round-trip correctly, but libpng 1.5.7 is not the + * ideal world so allow a drift (error_via_linear). + * + * 'image' has an alpha channel but 'output' does not then there + * will a strip-alpha-channel operation (because 'output' is + * linear), handle this by composing on black when doing the + * comparison. + */ + result = compare_two_images(image, &output, 1/*via_linear*/, + background); + if (!result) + break; + } +# endif /* PNG_SIMPLIFIED_WRITE_SUPPORTED */ + } + + freeimage(&output); + } + + freeimage(©); + + return result; +} + +static int +test_one_file(const char *file_name, format_list *formats, png_uint_32 opts, + int stride_extra, int log_pass) +{ + int result; + Image image; + + newimage(&image); + initimage(&image, opts, file_name, stride_extra); + result = read_one_file(&image); + if (result) + result = testimage(&image, opts, formats); + freeimage(&image); + + /* Ensure that stderr is flushed into any log file */ + fflush(stderr); + + if (log_pass) + { + if (result) + printf("PASS:"); + + else + printf("FAIL:"); + +# ifndef PNG_SIMPLIFIED_WRITE_SUPPORTED + printf(" (no write)"); +# endif + + print_opts(opts); + printf(" %s\n", file_name); + /* stdout may not be line-buffered if it is piped to a file, so: */ + fflush(stdout); + } + + else if (!result) + exit(1); + + return result; +} + +int +main(int argc, char **argv) +{ + png_uint_32 opts = FAST_WRITE; + format_list formats; + const char *touch = NULL; + int log_pass = 0; + int redundant = 0; + int stride_extra = 0; + int retval = 0; + int c; + + init_sRGB_to_d(); +#if 0 + init_error_via_linear(); +#endif + format_init(&formats); + + for (c=1; c<argc; ++c) + { + const char *arg = argv[c]; + + if (strcmp(arg, "--log") == 0) + log_pass = 1; + else if (strcmp(arg, "--fresh") == 0) + { + memset(gpc_error, 0, sizeof gpc_error); + memset(gpc_error_via_linear, 0, sizeof gpc_error_via_linear); + } + else if (strcmp(arg, "--file") == 0) +# ifdef PNG_STDIO_SUPPORTED + opts |= READ_FILE; +# else + return 77; /* skipped: no support */ +# endif + else if (strcmp(arg, "--memory") == 0) + opts &= ~READ_FILE; + else if (strcmp(arg, "--stdio") == 0) +# ifdef PNG_STDIO_SUPPORTED + opts |= USE_STDIO; +# else + return 77; /* skipped: no support */ +# endif + else if (strcmp(arg, "--name") == 0) + opts &= ~USE_STDIO; + else if (strcmp(arg, "--verbose") == 0) + opts |= VERBOSE; + else if (strcmp(arg, "--quiet") == 0) + opts &= ~VERBOSE; + else if (strcmp(arg, "--preserve") == 0) + opts |= KEEP_TMPFILES; + else if (strcmp(arg, "--nopreserve") == 0) + opts &= ~KEEP_TMPFILES; + else if (strcmp(arg, "--keep-going") == 0) + opts |= KEEP_GOING; + else if (strcmp(arg, "--fast") == 0) + opts |= FAST_WRITE; + else if (strcmp(arg, "--slow") == 0) + opts &= ~FAST_WRITE; + else if (strcmp(arg, "--accumulate") == 0) + opts |= ACCUMULATE; + else if (strcmp(arg, "--redundant") == 0) + redundant = 1; + else if (strcmp(arg, "--stop") == 0) + opts &= ~KEEP_GOING; + else if (strcmp(arg, "--strict") == 0) + opts |= STRICT; + else if (strcmp(arg, "--sRGB-16bit") == 0) + opts |= sRGB_16BIT; + else if (strcmp(arg, "--linear-16bit") == 0) + opts &= ~sRGB_16BIT; + else if (strcmp(arg, "--tmpfile") == 0) + { + if (c+1 < argc) + { + if (strlen(argv[++c]) >= sizeof tmpf) + { + fflush(stdout); + fprintf(stderr, "%s: %s is too long for a temp file prefix\n", + argv[0], argv[c]); + exit(99); + } + + /* Safe: checked above */ + strncpy(tmpf, argv[c], sizeof (tmpf)-1); + } + + else + { + fflush(stdout); + fprintf(stderr, "%s: %s requires a temporary file prefix\n", + argv[0], arg); + exit(99); + } + } + else if (strcmp(arg, "--touch") == 0) + { + if (c+1 < argc) + touch = argv[++c]; + + else + { + fflush(stdout); + fprintf(stderr, "%s: %s requires a file name argument\n", + argv[0], arg); + exit(99); + } + } + else if (arg[0] == '+') + { + png_uint_32 format = formatof(arg+1); + + if (format > FORMAT_COUNT) + exit(99); + + format_set(&formats, format); + } + else if (arg[0] == '-' && arg[1] != 0 && (arg[1] != '0' || arg[2] != 0)) + { + fflush(stdout); + fprintf(stderr, "%s: unknown option: %s\n", argv[0], arg); + exit(99); + } + else + { + if (format_is_initial(&formats)) + format_default(&formats, redundant); + + if (arg[0] == '-') + { + const int term = (arg[1] == '0' ? 0 : '\n'); + unsigned int ich = 0; + + /* Loop reading files, use a static buffer to simplify this and just + * stop if the name gets to long. + */ + static char buffer[4096]; + + do + { + int ch = getchar(); + + /* Don't allow '\0' in file names, and terminate with '\n' or, + * for -0, just '\0' (use -print0 to find to make this work!) + */ + if (ch == EOF || ch == term || ch == 0) + { + buffer[ich] = 0; + + if (ich > 0 && !test_one_file(buffer, &formats, opts, + stride_extra, log_pass)) + retval = 1; + + if (ch == EOF) + break; + + ich = 0; + --ich; /* so that the increment below sets it to 0 again */ + } + + else + buffer[ich] = (char)ch; + } while (++ich < sizeof buffer); + + if (ich) + { + buffer[32] = 0; + buffer[4095] = 0; + fprintf(stderr, "%s...%s: file name too long\n", buffer, + buffer+(4096-32)); + exit(99); + } + } + + else if (!test_one_file(arg, &formats, opts, stride_extra, log_pass)) + retval = 1; + } + } + + if (opts & ACCUMULATE) + { + unsigned int in; + + printf("static png_uint_16 gpc_error[16/*in*/][16/*out*/][4/*a*/] =\n"); + printf("{\n"); + for (in=0; in<16; ++in) + { + unsigned int out; + printf(" { /* input: %s */\n ", format_names[in]); + for (out=0; out<16; ++out) + { + unsigned int alpha; + printf(" {"); + for (alpha=0; alpha<4; ++alpha) + { + printf(" %d", gpc_error[in][out][alpha]); + if (alpha < 3) putchar(','); + } + printf(" }"); + if (out < 15) + { + putchar(','); + if (out % 4 == 3) printf("\n "); + } + } + printf("\n }"); + + if (in < 15) + putchar(','); + else + putchar('\n'); + } + printf("};\n"); + + printf("static png_uint_16 gpc_error_via_linear[16][4/*out*/][4] =\n"); + printf("{\n"); + for (in=0; in<16; ++in) + { + unsigned int out; + printf(" { /* input: %s */\n ", format_names[in]); + for (out=0; out<4; ++out) + { + unsigned int alpha; + printf(" {"); + for (alpha=0; alpha<4; ++alpha) + { + printf(" %d", gpc_error_via_linear[in][out][alpha]); + if (alpha < 3) putchar(','); + } + printf(" }"); + if (out < 3) + putchar(','); + } + printf("\n }"); + + if (in < 15) + putchar(','); + else + putchar('\n'); + } + printf("};\n"); + + printf("static png_uint_16 gpc_error_to_colormap[8/*i*/][8/*o*/][4] =\n"); + printf("{\n"); + for (in=0; in<8; ++in) + { + unsigned int out; + printf(" { /* input: %s */\n ", format_names[in]); + for (out=0; out<8; ++out) + { + unsigned int alpha; + printf(" {"); + for (alpha=0; alpha<4; ++alpha) + { + printf(" %d", gpc_error_to_colormap[in][out][alpha]); + if (alpha < 3) putchar(','); + } + printf(" }"); + if (out < 7) + { + putchar(','); + if (out % 4 == 3) printf("\n "); + } + } + printf("\n }"); + + if (in < 7) + putchar(','); + else + putchar('\n'); + } + printf("};\n"); + } + + if (retval == 0 && touch != NULL) + { + FILE *fsuccess = fopen(touch, "wt"); + + if (fsuccess != NULL) + { + int error = 0; + fprintf(fsuccess, "PNG simple API tests succeeded\n"); + fflush(fsuccess); + error = ferror(fsuccess); + + if (fclose(fsuccess) || error) + { + fflush(stdout); + fprintf(stderr, "%s: write failed\n", touch); + exit(99); + } + } + + else + { + fflush(stdout); + fprintf(stderr, "%s: open failed\n", touch); + exit(99); + } + } + + return retval; +} + +#else /* !PNG_SIMPLIFIED_READ_SUPPORTED */ +int main(void) +{ + fprintf(stderr, "pngstest: no read support in libpng, test skipped\n"); + /* So the test is skipped: */ + return 77; +} +#endif /* PNG_SIMPLIFIED_READ_SUPPORTED */ |