Hi all. A little while ago I did some testing on gwenview and found that image data gets lost when rotating an image. I'd like to confirm the issue, so if someone could test it on their system and report the results to the bug I opened, it would be very much appreaciated.

https://bugs.kde.org/show_bug.cgi?id=328282

Recently, I looked through the code to see if I could find where the issue is, but not without any luck. (I'm not that good at understanding code.)

I also looked through the code for digikam, as that app does not destroy data when rotating an image. There I did see an option to simply set the orientation tag, rather then actually modifying the image. Perhaps something similiar would work in gwenview, though that would not help to preserve data when other types of image modifications were made.

What is likely happening is that a new image file is being created and being filled with the newly modified image data, prior to that file being used to replace the existing one. This would result in the metadata being lost, unless it was explicitly copied over. To fix this bug, you would need to identify the metadata and explicitly copy it into the new file - assuming that is what the code is actually doing.