Re: tiff:photometric and CCITT compression

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Am 12.10.23 um 15:29 schrieb Bob Friesenhahn:
> On Wed, 11 Oct 2023, frechefuchs via Graphicsmagick-help wrote:
>>
>> To be sure, you mean removing the code that disables CCITT compression
>> if minis/black/ is requested?
> 
> Yes, since that is what you said was causing the issue.

Ha, that's right – in a way.  Because, I was far from expecting
uncommenting that code is all that is needed. :-)  Apparently, all the
necessary machinery to write 'minisblack' CCITT images is already in
place.  Which makes sense, in hindsight.

I can confirm that the attached patch enables GM to write CCITT encoded
TIFF files with photometric interpretation 'minisblack'.  I've done
tests with Group3 and 4 compression with stripped and tiled images.  No
suspicious behaviour in any image viewer.  Also, read-in the files by GM
again, without a problem.  tiffinfo looks good.  Processing GM output
with tiff2pdf (libtiff) and tifftopnm (netpbm), the output also looks good.

Tested with GraphicsMagick 1.4 snapshot-20231008 Q16 on Ubuntu 20.04.

Best,
fux
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