2017.05.02 12:56 "Re: [Tiff] Interesting change/problem in LibTiff 4.0.7 with unsupported compressions", by Michael Shiels
Just wondering if anyone has thoughts on this problem. Once I posted it doesn't' seem to have made it into the archive which means maybe it didn't get through at all??
This is a interesting situation since most people don't expect an error just from enumerating the directory and reading the tags. Maybe a warning would be more appropriate specifically for an inability to detail out the compression specific tags maybe??
Thanks.
Mike
From: tiff-bounces@lists.maptools.org [mailto:tiff-bounces@lists.maptools.org] On Behalf Of Michael | Shiels [ MaS \ Software \ Inc ]
Sent: Friday, April 28, 2017 4:38 PM
To: tiff@lists.maptools.org
Subject: [Tiff] Interesting change/problem in LibTiff 4.0.7 with unsupported compressions
I found a decent change in the behavior of Libtiff - after I updated from
the 3.5.6/3.5.7 era to the most recent (yes 15 year jump!!)
Specifically this piece of code - basically ends up tripping an error if the
compression is not compiled/activated in the code. So you can't even
peruse/move through a file without tripping an error.
/*
* An opportunity for compression mode dependent tag fixup
*/
(*tif->tif_fixuptags)(tif);
Our engine specifically watches for errors and assumes it's pretty fatal -
when really it's kinda benign - UNLESS I want to extract the image data
itself, right??
Surely that should be pretty benign to just enumerate through a TIFF - even
if you don't support the compression of each page??
Mike