Su, I am confident that the problem must be in this new code, which is written by a developer who has not worked with TIFF before. The developer has now updated his libtiff to 4.5.1 and is able to reproduce the problems. The code may be viewed at https://foss.heptapod.net/graphicsmagick/graphicsmagick/-/blob/branch/default/coders/tiff.c and is bracketed in 'EXPERIMENTAL_EXIF_TAGS' ifdefs.
If you are aware of a remedy, then it would be appreciated. Bob On Thu, Dec 28, 2023 at 1:15 PM Sulau via Tiff <[email protected]> wrote: > Hi Bob, > > would it be possible to share the submitted code, how the TIFF IFD and the > EXIF IFD are handled. > Are the error reported below from GraphicsMagick? How to reproduce this > error? > Then I could have a look. > > Handling such "Customer IFDs" was always a tricky thing, because the TIFF > IFD has to be written and re-read from file several times and IFDs have to > be switched in the correct way, especially for multi-image TIFF. Some > hints > about that could be found in the comments of custom_dir_EXIF_231.c and at > https://libtiff.gitlab.io/libtiff/functions/TIFFCustomDirectory.html > > And between 4.5.0 and 4.5.1 we speed up moving between IFDs for TIFF files > having a huge number of IFDs (images) and handling of sub-IFDs. > > Regards > Su > > > -----Ursprüngliche Nachricht----- > Von: Tiff [mailto:[email protected]] Im Auftrag von Bob > Friesenhahn via Tiff > Gesendet: Mittwoch, 20. Dezember 2023 23:07 > An: Tiff List <[email protected]> > Betreff: [Tiff] EXIF tag writing fails starting with libtiff 4.5.1? > > Recently a volunteer submitted code to GraphicsMagick's TIFF writer to > create an EXIF subifd. When I tested this, it did not work for me. > I was using latest libtiff from git. > > I did some investigating and found that the code works for libtiff > 4.4.0 and 4.5.0 but fails starting with 4.5.1. Is anyone aware of changes > which might cause the issue (or detect a problem which was not detected > before)? > > The test case writes three identical images in order, each with an > identical > EXIF IFD. > > The final errors reported are: > > 15:49:49 0:0.005317 0.000u 2345878 tiff.c/AddExifFields/4510/Coder: > Extracted tag from EXIF 11ah, Field 5, Long2 1, val 17895 XResolution > 15:49:49 0:0.005443 0.000u 2345878 tiff.c/TIFFWriteErrors/975/Coder: > Ignored: Error fetching directory link. (TIFFRewriteDirectory) > 15:49:49 0:0.005476 0.000u 2345878 tiff.c/TIFFWriteErrors/975/Coder: > Ignored: Error fetching directory link. (TIFFRewriteDirectory) > 15:49:49 0:0.006473 0.000u 2345878 tiff.c/WriteTIFFImage/6687/Coder: > Removed broken output file "input_truecolor.tiff" > 15:49:49 0:0.006495 0.000u 2345878 > constitute.c/WriteImage/2325/Coder: Returned from "TIFF" encoder, Failed > ./utilities/gm convert: TIFF directory is missing required "ImageLength" > field. (MissingRequired). > > Bob > -- > Bob Friesenhahn > [email protected], http://www.simplesystems.org/users/bfriesen/ > GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ > Public Key, http://www.simplesystems.org/users/bfriesen/public-key.txt > _______________________________________________ > Tiff mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/tiff > > _______________________________________________ > Tiff mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/tiff >
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