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Diffstat (limited to 'Build/source/libs/libpng/libpng-1.6.2/contrib/tools/makesRGB.c')
-rw-r--r--Build/source/libs/libpng/libpng-1.6.2/contrib/tools/makesRGB.c430
1 files changed, 0 insertions, 430 deletions
diff --git a/Build/source/libs/libpng/libpng-1.6.2/contrib/tools/makesRGB.c b/Build/source/libs/libpng/libpng-1.6.2/contrib/tools/makesRGB.c
deleted file mode 100644
index e66c9f1576b..00000000000
--- a/Build/source/libs/libpng/libpng-1.6.2/contrib/tools/makesRGB.c
+++ /dev/null
@@ -1,430 +0,0 @@
-/* makesRGB.c -- build sRGB-to-linear and linear-to-sRGB conversion tables
- *
- * Last changed in libpng 1.6.0 [February 14, 2013]
- *
- * COPYRIGHT: Written by John Cunningham Bowler, 2013.
- * To the extent possible under law, the author has waived all copyright and
- * related or neighboring rights to this work. This work is published from:
- * United States.
- *
- * Make a table to convert 8-bit sRGB encoding values into the closest 16-bit
- * linear value.
- *
- * Make two tables to take a linear value scaled to 255*65535 and return an
- * approximation to the 8-bit sRGB encoded value. Calculate the error in these
- * tables and display it.
- */
-#define _C99_SOURCE 1
-#include <stdio.h>
-#include <math.h>
-#include <stdlib.h>
-
-/* pngpriv.h includes the definition of 'PNG_sRGB_FROM_LINEAR' which is required
- * to verify the actual code.
- */
-#include "../../pngpriv.h"
-
-#include "sRGB.h"
-
-/* The tables are declared 'const' in pngpriv.h, so this redefines the tables to
- * be used.
- */
-#define png_sRGB_table sRGB_table
-#define png_sRGB_base sRGB_base
-#define png_sRGB_delta sRGB_delta
-
-static png_uint_16 png_sRGB_table[256];
-static png_uint_16 png_sRGB_base[512];
-static png_byte png_sRGB_delta[512];
-
-static const unsigned int max_input = 255*65535;
-
-double
-fsRGB(double l)
-{
- return sRGB_from_linear(l/max_input);
-}
-
-double
-sRGB(unsigned int i)
-{
- return fsRGB(i);
-}
-
-double
-finvsRGB(unsigned int i)
-{
- return 65535 * linear_from_sRGB(i/255.);
-}
-
-png_uint_16
-invsRGB(unsigned int i)
-{
- unsigned int x = nearbyint(finvsRGB(i));
-
- if (x > 65535)
- {
- fprintf(stderr, "invsRGB(%u) overflows to %u\n", i, x);
- exit(1);
- }
-
- return (png_uint_16)x;
-}
-
-int
-main(int argc, char **argv)
-{
- unsigned int i, i16, ibase;
- double min_error = 0;
- double max_error = 0;
- double min_error16 = 0;
- double max_error16 = 0;
- double adjust;
- double adjust_lo = 0.4, adjust_hi = 0.6, adjust_mid = 0.5;
- unsigned int ec_lo = 0, ec_hi = 0, ec_mid = 0;
- unsigned int error_count = 0;
- unsigned int error_count16 = 0;
- int test_only = 0;
-
- if (argc > 1)
- test_only = strcmp("--test", argv[1]) == 0;
-
- /* Initialize the encoding table first. */
- for (i=0; i<256; ++i)
- {
- png_sRGB_table[i] = invsRGB(i);
- }
-
- /* Now work out the decoding tables (this is where the error comes in because
- * there are 512 set points and 512 straight lines between them.)
- */
- for (;;)
- {
- if (ec_lo == 0)
- adjust = adjust_lo;
-
- else if (ec_hi == 0)
- adjust = adjust_hi;
-
- else if (ec_mid == 0)
- adjust = adjust_mid;
-
- else if (ec_mid < ec_hi)
- adjust = (adjust_mid + adjust_hi)/2;
-
- else if (ec_mid < ec_lo)
- adjust = (adjust_mid + adjust_lo)/2;
-
- else
- {
- fprintf(stderr, "not reached: %u .. %u .. %u\n", ec_lo, ec_mid, ec_hi);
- exit(1);
- }
-
- /* Calculate the table using the current 'adjust' */
- for (i=0; i<=511; ++i)
- {
- double lo = 255 * sRGB(i << 15);
- double hi = 255 * sRGB((i+1) << 15);
- unsigned int calc;
-
- calc = nearbyint((lo+adjust) * 256);
- if (calc > 65535)
- {
- fprintf(stderr, "table[%d][0]: overflow %08x (%d)\n", i, calc,
- calc);
- exit(1);
- }
- png_sRGB_base[i] = calc;
-
- calc = nearbyint((hi-lo) * 32);
- if (calc > 255)
- {
- fprintf(stderr, "table[%d][1]: overflow %08x (%d)\n", i, calc,
- calc);
- exit(1);
- }
- png_sRGB_delta[i] = calc;
- }
-
- /* Check the 16-bit linear values alone: */
- error_count16 = 0;
- for (i16=0; i16 <= 65535; ++i16)
- {
- unsigned int i = 255*i16;
- unsigned int iexact = nearbyint(255*sRGB(i));
- unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
-
- if (icalc != iexact)
- ++error_count16;
- }
-
- /* Now try changing the adjustment. */
- if (ec_lo == 0)
- ec_lo = error_count16;
-
- else if (ec_hi == 0)
- ec_hi = error_count16;
-
- else if (ec_mid == 0)
- {
- ec_mid = error_count16;
- printf("/* initial error counts: %u .. %u .. %u */\n", ec_lo, ec_mid,
- ec_hi);
- }
-
- else if (error_count16 < ec_mid)
- {
- printf("/* adjust (mid ): %f: %u -> %u */\n", adjust, ec_mid,
- error_count16);
- ec_mid = error_count16;
- adjust_mid = adjust;
- }
-
- else if (adjust < adjust_mid && error_count16 < ec_lo)
- {
- printf("/* adjust (low ): %f: %u -> %u */\n", adjust, ec_lo,
- error_count16);
- ec_lo = error_count16;
- adjust_lo = adjust;
- }
-
- else if (adjust > adjust_mid && error_count16 < ec_hi)
- {
- printf("/* adjust (high): %f: %u -> %u */\n", adjust, ec_hi,
- error_count16);
- ec_hi = error_count16;
- adjust_hi = adjust;
- }
-
- else
- {
- adjust = adjust_mid;
- printf("/* adjust: %f: %u */\n", adjust, ec_mid);
- break;
- }
- }
-
- /* For each entry in the table try to adjust it to minimize the error count
- * in that entry. Each entry corresponds to 128 input values.
- */
- for (ibase=0; ibase<65536; ibase+=128)
- {
- png_uint_16 base = png_sRGB_base[ibase >> 7], trybase = base, ob=base;
- png_byte delta = png_sRGB_delta[ibase >> 7], trydelta = delta, od=delta;
- unsigned int ecbase = 0, eco;
-
- for (;;)
- {
- png_sRGB_base[ibase >> 7] = trybase;
- png_sRGB_delta[ibase >> 7] = trydelta;
-
- /* Check the 16-bit linear values alone: */
- error_count16 = 0;
- for (i16=ibase; i16 < ibase+128; ++i16)
- {
- unsigned int i = 255*i16;
- unsigned int iexact = nearbyint(255*sRGB(i));
- unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
-
- if (icalc != iexact)
- ++error_count16;
- }
-
- if (error_count16 == 0)
- break;
-
- if (ecbase == 0)
- {
- eco = ecbase = error_count16;
- ++trybase; /* First test */
- }
-
- else if (error_count16 < ecbase)
- {
- if (trybase > base)
- {
- base = trybase;
- ++trybase;
- }
- else if (trybase < base)
- {
- base = trybase;
- --trybase;
- }
- else if (trydelta > delta)
- {
- delta = trydelta;
- ++trydelta;
- }
- else if (trydelta < delta)
- {
- delta = trydelta;
- --trydelta;
- }
- else
- {
- fprintf(stderr, "makesRGB: impossible\n");
- exit(1);
- }
- ecbase = error_count16;
- }
-
- else
- {
- if (trybase > base)
- trybase = base-1;
- else if (trybase < base)
- {
- trybase = base;
- ++trydelta;
- }
- else if (trydelta > delta)
- trydelta = delta-1;
- else if (trydelta < delta)
- break; /* end of tests */
- }
- }
-
- png_sRGB_base[ibase >> 7] = base;
- png_sRGB_delta[ibase >> 7] = delta;
- if (base != ob || delta != od)
- {
- printf("/* table[%u]={%u,%u} -> {%u,%u} %u -> %u errors */\n",
- ibase>>7, ob, od, base, delta, eco, ecbase);
- }
- else if (0)
- printf("/* table[%u]={%u,%u} %u errors */\n", ibase>>7, ob, od,
- ecbase);
- }
-
- /* Only do the full (slow) test at the end: */
- min_error = -.4999;
- max_error = .4999;
- error_count = 0;
-
- for (i=0; i <= max_input; ++i)
- {
- unsigned int iexact = nearbyint(255*sRGB(i));
- unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
-
- if (icalc != iexact)
- {
- double err = 255*sRGB(i) - icalc;
-
- if (err > (max_error+.001) || err < (min_error-.001))
- {
- printf(
- "/* 0x%08x: exact: %3d, got: %3d [tables: %08x, %08x] (%f) */\n",
- i, iexact, icalc, png_sRGB_base[i>>15],
- png_sRGB_delta[i>>15], err);
- }
-
- ++error_count;
- if (err > max_error)
- max_error = err;
- else if (err < min_error)
- min_error = err;
- }
- }
-
- /* Re-check the 16-bit cases too, including the warning if there is an error
- * bigger than 1.
- */
- error_count16 = 0;
- max_error16 = 0;
- min_error16 = 0;
- for (i16=0; i16 <= 65535; ++i16)
- {
- unsigned int i = 255*i16;
- unsigned int iexact = nearbyint(255*sRGB(i));
- unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
-
- if (icalc != iexact)
- {
- double err = 255*sRGB(i) - icalc;
-
- ++error_count16;
- if (err > max_error16)
- max_error16 = err;
- else if (err < min_error16)
- min_error16 = err;
-
- if (abs(icalc - iexact) > 1)
- printf(
- "/* 0x%04x: exact: %3d, got: %3d [tables: %08x, %08x] (%f) */\n",
- i16, iexact, icalc, png_sRGB_base[i>>15],
- png_sRGB_delta[i>>15], err);
- }
- }
-
- /* Check the round trip for each 8-bit sRGB value. */
- for (i16=0; i16 <= 255; ++i16)
- {
- unsigned int i = 255 * png_sRGB_table[i16];
- unsigned int iexact = nearbyint(255*sRGB(i));
- unsigned int icalc = PNG_sRGB_FROM_LINEAR(i);
-
- if (i16 != iexact)
- {
- fprintf(stderr, "8-bit rounding error: %d -> %d\n", i16, iexact);
- exit(1);
- }
-
- if (icalc != i16)
- {
- double finv = finvsRGB(i16);
-
- printf("/* 8-bit roundtrip error: %d -> %f -> %d(%f) */\n",
- i16, finv, icalc, fsRGB(255*finv));
- }
- }
-
-
- printf("/* error: %g - %g, %u (%g%%) of readings inexact */\n",
- min_error, max_error, error_count, (100.*error_count)/max_input);
- printf("/* 16-bit error: %g - %g, %u (%g%%) of readings inexact */\n",
- min_error16, max_error16, error_count16, (100.*error_count16)/65535);
-
- if (!test_only)
- {
- printf("PNG_CONST png_uint_16 png_sRGB_table[256] =\n{\n ");
- for (i=0; i<255; )
- {
- do
- {
- printf("%d,", png_sRGB_table[i++]);
- }
- while ((i & 0x7) != 0 && i<255);
- if (i<255) printf("\n ");
- }
- printf("%d\n};\n\n", png_sRGB_table[i]);
-
-
- printf("PNG_CONST png_uint_16 png_sRGB_base[512] =\n{\n ");
- for (i=0; i<511; )
- {
- do
- {
- printf("%d,", png_sRGB_base[i++]);
- }
- while ((i & 0x7) != 0 && i<511);
- if (i<511) printf("\n ");
- }
- printf("%d\n};\n\n", png_sRGB_base[i]);
-
- printf("PNG_CONST png_byte png_sRGB_delta[512] =\n{\n ");
- for (i=0; i<511; )
- {
- do
- {
- printf("%d,", png_sRGB_delta[i++]);
- }
- while ((i & 0xf) != 0 && i<511);
- if (i<511) printf("\n ");
- }
- printf("%d\n};\n\n", png_sRGB_delta[i]);
- }
-
- return 0;
-}