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[devel] Fix pngvalid.c with ACCURATE_SCALE

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and update scripts/pnglibconf.h.prebuilt
This commit is contained in:
John Bowler
2011-06-22 23:13:01 -05:00
committed by Glenn Randers-Pehrson
parent 5bcd0a8c14
commit fcd7c13ffd
4 changed files with 62 additions and 56 deletions
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79
pngvalid.c
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@@ -6732,47 +6732,48 @@ gamma_component_validate(PNG_CONST char *name, PNG_CONST validate_info *vi,
* This is only done for older libpng versions when the 'inaccurate'
* (chop) method of scaling was used.
*/
# if !PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED && \
PNG_LIBPNG_VER < 10504
/* This may be required for other components in the future, but
* at present the presence of gamma correction effectively
* prevents the errors in the component scaling (I don't quite
* understand why, but since it's better this way I care not to
* ask, JB 20110419.)
*/
if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
vi->sbit + vi->isbit_shift == 16)
{
tmp = ((id >> 8) - .5)/255;
if (tmp > 0)
# ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
# if PNG_LIBPNG_VER < 10504
/* This may be required for other components in the future,
* but at present the presence of gamma correction effectively
* prevents the errors in the component scaling (I don't quite
* understand why, but since it's better this way I care not
* to ask, JB 20110419.)
*/
if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
vi->sbit + vi->isbit_shift == 16)
{
is_lo = ceil(outmax * tmp - vi->maxout_total);
if (is_lo < 0) is_lo = 0;
tmp = ((id >> 8) - .5)/255;
if (tmp > 0)
{
is_lo = ceil(outmax * tmp - vi->maxout_total);
if (is_lo < 0) is_lo = 0;
}
else
is_lo = 0;
tmp = ((id >> 8) + .5)/255;
if (tmp < 1)
{
is_hi = floor(outmax * tmp + vi->maxout_total);
if (is_hi > outmax) is_hi = outmax;
}
else
is_hi = outmax;
if (!(od < is_lo || od > is_hi))
{
if (encoded_error < vi->outlog)
return i;
pass = "within 8 bit limits:\n";
}
}
else
is_lo = 0;
tmp = ((id >> 8) + .5)/255;
if (tmp < 1)
{
is_hi = floor(outmax * tmp + vi->maxout_total);
if (is_hi > outmax) is_hi = outmax;
}
else
is_hi = outmax;
if (!(od < is_lo || od > is_hi))
{
if (encoded_error < vi->outlog)
return i;
pass = "within 8 bit limits:\n";
}
}
# endif
# endif
}
else /* !use_input_precision */