SUMMARY DigiKam cannot create xmp for xcf when using Adjust Time Date. Configure - digiKam Write to sidecar files is set Write to XMP sidecar for read-only item only. Adjust Time Date gives an error - Failed to update file timestamp. STEPS TO REPRODUCE 1. xcf and using Adjust Time Date 2. 3. OBSERVED RESULT XMP file not created. EXPECTED RESULT SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: (available in About System) KDE Plasma Version: KDE Frameworks Version: Qt Version: ADDITIONAL INFORMATION
The problem with XCF files is specific. The Time Adjust Tool must be able to read metadata beforehand. With XCF files from Gimp-2.10 and newer this fails with Exiv2. ExifTool can help us here in the future. A sidecar must first exist as a workaround. Write a tag or rating in the XCF image. Now with a sidecar, the Time Adjust Tool will also work. Maik
Maik, It will be safe later to use Exiftool wrapper with TimeAdjust plugin. There is already a method to import metadata from file with ExifTool to Exiv2 container (.exv). Like this, changes to write in the plugin will be very limited. https://invent.kde.org/graphics/digikam/-/blob/master/core/libs/metadataengine/exiftool/exiftoolparser.h#L127 The inverse is not yet fully ready to use : https://invent.kde.org/graphics/digikam/-/blob/master/core/libs/metadataengine/exiftool/exiftoolparser.h#L144 To apply changes for non present tags in target, or for existing tags work as expected. It miss a rule to check the difference between original and target EXV container to list tags to remove in target file. It's a little bit complicated as EXV container cannot be used to list rules to drop tags. parsing the differences between 2 EXV files is easy, but the dropped Exiv2 tags list must be translated to ExifTool syntax. This last stage is a little bit complicated. Gilles
@hannesj@hot.ee digiKam 8.0.0 is out. This entry still valid with this release ? Best regards Gilles Caulier
The problem persists because ExifTool can only read and not write the Gimp XCF files. Sidecars must currently be used for XCF files. Maik
Well it's clear. As Maik explain in comment #4, XCF metadata is in read only with ExifTool. If you want to see this behavior changed in the future, report is UPSTREAM problem to ExifTool team.