| /*- |
| * pngstest.c |
| * |
| * Last changed in libpng 1.6.31 [July 27, 2017] |
| * Copyright (c) 2013-2017 John Cunningham Bowler |
| * |
| * 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 |
| |
| /* 1.6.1 added support for the configure test harness, which uses 77 to indicate |
| * a skipped test, in earlier versions we need to succeed on a skipped test, so: |
| */ |
| #if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H) |
| # define SKIP 77 |
| #else |
| # define SKIP 0 |
| #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 png_uint_32 color_seed[2]; |
| |
| static void |
| reseed(void) |
| { |
| color_seed[0] = 0x12345678U; |
| color_seed[1] = 0x9abcdefU; |
| } |
| |
| static void |
| random_color(png_colorp color) |
| { |
| 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 USE_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 |
| #define NO_RESEED 512 /* do not reseed on each new file */ |
| #define GBG_ERROR 1024 /* do not ignore the gamma+background_rgb_to_gray |
| * libpng warning. */ |
| |
| static void |
| print_opts(png_uint_32 opts) |
| { |
| if (opts & USE_FILE) |
| printf(" --file"); |
| if (opts & USE_STDIO) |
| printf(" --stdio"); |
| if (!(opts & STRICT)) |
| printf(" --nostrict"); |
| 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"); |
| if (opts & NO_RESEED) |
| printf(" --noreseed"); |
| #if PNG_LIBPNG_VER < 10700 /* else on by default */ |
| if (opts & GBG_ERROR) |
| printf(" --fault-gbg-warning"); |
| #endif |
| } |
| |
| #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 const char * 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; |
| size_t input_memory_size; |
| png_bytep buffer; |
| ptrdiff_t stride; |
| size_t bufsize; |
| 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) |
| { |
| 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", ""); |
| } |
| |
| /* Separate out the gamma+background_rgb_to_gray warning because it may |
| * produce opaque component errors: |
| */ |
| else if (image->image.warning_or_error != 0 && |
| (strcmp(image->image.message, |
| "libpng does not support gamma+background+rgb_to_gray") == 0 ? |
| (image->opts & GBG_ERROR) != 0 : (image->opts & STRICT) != 0)) |
| return logerror(image, image->file_name, (image->opts & GBG_ERROR) != 0 ? |
| " --fault-gbg-warning" : " --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; |
| } |
| } |
| } |
| |
| /* Conversion 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 */ |
| # include "pngstest-errors.h" /* 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; /* Accumulate 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; |
| png_uint_32 y; |
| Transform tr; |
| int btoa[4]={0,0,0,0}; |
| |
| /* 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) |
| { |
| # ifdef __GNUC__ |
| # define BYTE_CHARS 20 /* 2^32: GCC sprintf warning */ |
| # else |
| # define BYTE_CHARS 3 /* 2^8: real maximum value */ |
| # endif |
| /* Check the original image first, |
| * TODO: deal with input images with bad pixel values? |
| */ |
| if (amax >= a->image.colormap_entries) |
| { |
| char pindex[3+2*BYTE_CHARS]; |
| sprintf(pindex, "%d[%u]", amax, |
| (png_byte)/*SAFE*/a->image.colormap_entries); |
| return logerror(a, a->file_name, ": bad pixel index: ", pindex); |
| } |
| |
| else if (bmax >= b->image.colormap_entries) |
| { |
| char pindex[3+2*BYTE_CHARS]; |
| sprintf(pindex, "%d[%u]", bmax, |
| (png_byte)/*SAFE*/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; |
| /* FALLTHROUGH */ |
| case 3: |
| if (pua[btoa[2]] != pub[2]) break; |
| /* FALLTHROUGH */ |
| case 2: |
| if (pua[btoa[1]] != pub[1]) break; |
| /* FALLTHROUGH */ |
| 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; |
| /* FALLTHROUGH */ |
| case 3: |
| if (psa[btoa[2]] != psb[2]) break; |
| /* FALLTHROUGH */ |
| case 2: |
| if (psa[btoa[1]] != psb[1]) break; |
| /* FALLTHROUGH */ |
| 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 & USE_FILE) || (image->opts & USE_STDIO)) |
| { |
| /* memory or stdio. */ |
| FILE *f = fopen(image->file_name, "rb"); |
| |
| if (f != NULL) |
| { |
| if (image->opts & USE_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 |
|