mirror of
https://git.code.sf.net/p/libpng/code.git
synced 2025-07-10 18:04:09 +02:00
[libpng17] Removed some duplicated code from png.c and contrib/tools/scale.c
and changed some png_warning() calls to png_app_error() calls in pngwutil.c
This commit is contained in:
John Bowler
Glenn Randers-Pehrson
parent
b4e241559e
commit
0cf9c7d63d
@ -205,244 +205,6 @@ main(int argc, const char **argv)
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}
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if (argc < 2+firstsrc)
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usage(argv[0]);
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target = strtoul(argv[firstsrc++], 0, 0);
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if (target == 0) usage(argv[0]);
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for (i=firstsrc; i<argc; ++i)
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{
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unsigned long source = strtoul(argv[i], 0, 0);
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if (source == 0) usage(argv[0]);
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if (!find(denominator ? source : target, denominator ? target : source,
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maxshift ? 0 : 1+code, -1))
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err = 1;
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if (minshift > shift) shift = minshift;
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}
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if (maxshift) for (i=firstsrc; i<argc; ++i)
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{
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unsigned long source = strtoul(argv[i], 0, 0);
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if (!find(denominator ? source : target, denominator ? target : source,
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code ? 4 : 1, shift))
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err = 1;
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}
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/* Just an exit code - the printout above lists the problem */
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return err;
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}
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/* Given a target range and a source range work out an expression to scale from
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* the source to the target of the form:
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*
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* (number * mult + add)>>16
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*
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* The command arguments are:
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*
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* scale target source
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*
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* and the program works out a pair of numbers, mult and add, that evaluate:
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*
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* number * target
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* round( --------------- )
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* source
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*
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* exactly for number in the range 0..source
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*/
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#define _ISOC99_SOURCE 1
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <math.h>
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static double minerr;
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static unsigned long minmult, minadd, minshift;
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static long mindelta;
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static int
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test(unsigned long target, unsigned long source, unsigned long mult,
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long add, unsigned long shift, long delta)
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{
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unsigned long i;
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double maxerr = 0;
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double rs = (double)target/source;
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for (i=0; i<=source; ++i)
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{
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unsigned long t = i*mult+add;
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double err = fabs((t >> shift) - i*rs);
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if (err > minerr)
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return 0;
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if (err > maxerr)
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maxerr = err;
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}
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if (maxerr < minerr)
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{
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minerr = maxerr;
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minmult = mult;
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minadd = add;
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minshift = shift;
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mindelta = delta;
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}
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return maxerr < .5;
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}
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static int
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dotest(unsigned long target, unsigned long source, unsigned long mult,
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long add, unsigned long shift, long delta, int print)
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{
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if (test(target, source, mult, add, shift, delta))
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{
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if (print & 4)
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printf(" {%11lu,%6ld /* >>%lu */ }, /* %lu/%lu */\n",
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mult, add, shift, target, source);
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else if (print & 2)
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printf(" {%11lu,%6ld,%3lu }, /* %lu/%lu */\n",
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mult, add, shift, target, source);
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else if (print)
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printf("number * %lu/%lu = (number * %lu + %ld) >> %lu [delta %ld]\n",
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target, source, mult, add, shift, delta);
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return 1;
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}
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return 0;
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}
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static int
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find(unsigned long target, unsigned long source, int print, int fixshift)
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{
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unsigned long shift = 0;
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unsigned long shiftlim = 0;
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/* In the final math the sum is at most (source*mult+add) >> shift, so:
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*
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* source*mult+add < 1<<32
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* mult < (1<<32)/source
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*
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* but:
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*
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* mult = (target<<shift)/source
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*
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* so:
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*
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* (target<<shift) < (1<<32)
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*/
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if (fixshift < 0)
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while ((target<<shiftlim) < 0x80000000U) ++shiftlim;
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else
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shift = shiftlim = (unsigned long)fixshift;
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minerr = 1E8;
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for (; shift<=shiftlim; ++shift)
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{
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unsigned long mult = ((target<<shift) + (source>>1)) / source;
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long delta;
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long limit = 1; /* seems to be sufficient */
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long add, start, end;
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end = 1<<shift;
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start = -end;
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for (add=start; add<=end; ++add)
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if (dotest(target,source,mult,add,shift,0,print))
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return 1;
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for (delta=1; delta<=limit; ++delta)
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{
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# if 0
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fprintf(stderr, "%lu/%lu: shift %lu, delta %lu\n", target, source,
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shift, delta);
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# endif
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for (add=start; add<=end; ++add)
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{
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if (dotest(target, source, mult-delta, add, shift, -delta, print))
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return 1;
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if (dotest(target, source, mult+delta, add, shift, delta, print))
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return 1;
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}
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}
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}
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if (print & 4)
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printf(" {%11lu,%6ld /* >>%lu */ }, /* %lu/%lu ERROR: .5+%g*/\n",
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minmult, minadd, minshift, target, source, minerr-.5);
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else if (print & 2)
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printf(" {%11lu,%6ld,%3lu }, /* %lu/%lu ERROR: .5+%g*/\n",
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minmult, minadd, minshift, target, source, minerr-.5);
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else if (print)
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printf(
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"number * %lu/%lu ~= (number * %lu + %ld) >> %lu +/-.5+%g [delta %ld]\n",
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target, source, minmult, minadd, minshift, minerr-.5, mindelta);
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return 0;
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}
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static void
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usage(const char *prog)
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{
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fprintf(stderr,
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"usage: %s {--denominator|--maxshift|--code} target {source}\n"
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" For each 'source' prints 'mult' and 'add' such that:\n\n"
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" (number * mult + add) >> 16 = round(number*target/source)\n\n"
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" for all integer values of number in the range 0..source.\n\n"
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" --denominator: swap target and source (specify a single source first\n"
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" and follow with multiple targets.)\n"
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" --maxshift: find the lowest shift value that works for all the\n"
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" repeated 'source' values\n"
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" --code: output C code for array/structure initialization\n",
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prog);
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exit(1);
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}
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int
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main(int argc, const char **argv)
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{
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int i, err = 0, maxshift = 0, firstsrc = 1, code = 0, denominator = 0;
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unsigned long target, shift = 0;
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while (argc > 1)
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{
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if (strcmp(argv[firstsrc], "--maxshift") == 0)
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{
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maxshift = 1;
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++firstsrc;
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}
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else if (strcmp(argv[firstsrc], "--code") == 0)
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{
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code = 1;
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++firstsrc;
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}
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else if (strcmp(argv[firstsrc], "--denominator") == 0)
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{
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denominator = 1;
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++firstsrc;
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}
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else
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break;
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}
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if (argc < 2+firstsrc)
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usage(argv[0]);
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16
png.c
16
png.c
@ -253,22 +253,6 @@ png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
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create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
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# endif
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/* Added at libpng-1.2.6 */
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# ifdef PNG_USER_LIMITS_SUPPORTED
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create_struct.user_width_max = PNG_USER_WIDTH_MAX;
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create_struct.user_height_max = PNG_USER_HEIGHT_MAX;
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# ifdef PNG_USER_CHUNK_CACHE_MAX
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/* Added at libpng-1.2.43 and 1.4.0 */
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create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
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# endif
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# ifdef PNG_USER_CHUNK_MALLOC_MAX
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/* Added at libpng-1.2.43 and 1.4.1 */
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create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
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# endif
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# endif
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/* The following two API calls simply set fields in png_struct, so it is safe
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* to do them now even though error handling is not yet set up.
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*/
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13
pngwutil.c
13
pngwutil.c
@ -1427,11 +1427,8 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
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{
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if (num_trans <= 0 || num_trans > png_ptr->num_palette)
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{
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/* This is an error which can only be reliably detected late, change to
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* a png_app_warning here so that it will fail in debug. It should be
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* a png_app_error.
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*/
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png_app_warning(png_ptr,
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/* This is an error which can only be reliably detected late. */
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png_app_error(png_ptr,
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"Invalid number of transparent colors specified");
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return;
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}
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@ -1447,7 +1444,7 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
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if (tran->gray >= (1 << png_ptr->bit_depth))
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{
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/* This can no longer happen because it is checked in png_set_tRNS */
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png_warning(png_ptr,
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png_app_error(png_ptr,
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"Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
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return;
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@ -1470,7 +1467,7 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
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#endif
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{
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/* Also checked in png_set_tRNS */
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png_warning(png_ptr,
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png_app_error(png_ptr,
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"Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
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return;
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}
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@ -1481,7 +1478,7 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
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else
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{
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/* Checked in png_set_tRNS */
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png_warning(png_ptr, "Can't write tRNS with an alpha channel");
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png_app_error(png_ptr, "Can't write tRNS with an alpha channel");
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}
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}
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#endif
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