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new update from Scott

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This commit is contained in:
Frank Warmerdam 2001-09-24 19:54:36 +00:00
parent 19ebdba611
commit d3daae9697
1 changed files with 28 additions and 11 deletions
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39
libtiff/tif_ojpeg.c
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@ -1552,6 +1552,18 @@ OJPEGVSetField(register TIFF *tif,ttag_t tag,va_list ap)
switch (tag)
{
# ifdef COLORIMETRY_SUPPORT
/* If a "ReferenceBlackWhite" TIFF tag appears in the file explicitly, undo
any modified default definition that we might have installed below, then
install the real one.
*/
case TIFFTAG_REFERENCEBLACKWHITE : if (td->td_refblackwhite)
{
_TIFFfree(td->td_refblackwhite);
td->td_refblackwhite = 0;
};
# endif /* COLORIMETRY_SUPPORT */
default : return
(*sp->vsetparent)(tif,tag,ap);
# ifdef COLORIMETRY_SUPPORT
@ -1569,20 +1581,25 @@ OJPEGVSetField(register TIFF *tif,ttag_t tag,va_list ap)
"PhotometricInterpretation" tag should always appear before an optional
"ReferenceBlackWhite" tag. So, we slyly peek ahead when we discover the
desired photometry, by installing modified black and white reference
levels. We install a pointer to a statically-allocated array, which
lets it be overridden without "dangling" memory references, and which
should be reasonably safe since most client applications treat this data
as "read only".
levels.
*/
case TIFFTAG_PHOTOMETRIC:
case TIFFTAG_PHOTOMETRIC :
if ( (v32 = (*sp->vsetparent)(tif,tag,ap))
&& td->td_photometric == PHOTOMETRIC_YCBCR )
{
static float refbw[6]={0,255,128,255,128,255};
&& td->td_photometric == PHOTOMETRIC_YCBCR
)
if (td->td_refblackwhite = _TIFFmalloc(6*sizeof(float)))
{ register long top = 1 << td->td_bitspersample;
td->td_refblackwhite = _TIFFmalloc(sizeof(float)*6);
_TIFFmemcpy( td->td_refblackwhite, refbw, sizeof(float)*6 );
};
td->td_refblackwhite[0] = 0;
td->td_refblackwhite[1] = td->td_refblackwhite[3] =
td->td_refblackwhite[5] = top - 1;
td->td_refblackwhite[2] = td->td_refblackwhite[4] = top >> 1;
}
else
{
TIFFError(tif->tif_name,"Cannot define default reference black and white levels");
v32 = 0;
};
return v32;
# endif /* COLORIMETRY_SUPPORT */