2010.04.26 18:39 "[Tiff] Bug in tif_print.c for
TIFFTAG_REFERENCEBLACKWHITE", by Edward Lam
Thread
2010.04.26 20:59 "Re: [Tiff] Bug in tif_print.c for TIFFTAG_REFERENCEBLACKWHITE", by Olivier Paquet
On Mon, Apr 26, 2010 at 4:12 PM, Edward Lam <edward@sidefx.com> wrote:
Edward Lam wrote:
I have an 6-Bit RGBA image and using tiffinfo on it gives: >Er, I meant 8-bit here of course.
I also noticed another problem with the number of expected floats for TIFFTAG_REFERENCEBLACKWHITE in the documentation for TIFFSetField:
http://libtiff.maptools.org/man/TIFFSetField.3tiff.html
where it says:
> 2*SamplesPerPixel
That's also what the TIFF spec says in appendix A. Of course, other mentions of the tag specify 6 float. The spec also says:
The ordering of pairs is the same as those for pixel components of
the PhotometricInterpretation type. ReferenceBlackWhite can be applied
to images with a PhotometricInterpretation value of RGB or YCbCr.
ReferenceBlackWhite is not used with other PhotometricInterpretation values.
Which implies the tag will only ever have 6 values as both RGB and YCbCr have 3 components. libtiff always reads/writes 6 floats so it is definitely wrong to try to display 8 values.
Are there any objections to hardcoding the output of 6 values?
Olivier