Created attachment 102876 [details] original file scanned from a newspaper Running on Mageia 6 Cauldron (development) $ gwenview --version org.kde.gwenview 16.11.90 Look at the attached images: Original.jpg is original file scanned from a newspaper. Rotated.jpg is saved from gwenview after having rotated original right. You see the leftmost text character column is chopped off, and then added rightmost (and it looks like that part it is mirrored)
Created attachment 102877 [details] rotated in gwenview and saved
Note: Error it is not visible in gwenview right after rotation - only when reading back the saved file, so it seem error comes when saving?
Downstream bug, Mageia: https://bugs.mageia.org/show_bug.cgi?id=19986
Still valid Gwenview Version 16.12.3
Still valid. Also tested on a fresh Mageia 6 install this morning, now on i586. Kolourpaint and Showfoto handles the rotation OK.
Confirmed on gwenview from git master, it does cut writing off and move the image data.
Created attachment 140451 [details] JPEG photo where this issue occurs I believe I'm running into the same issue. When using the Rotate Left or Rotate Right buttons on certain JPEGs, the saved image has 8 pixel rows shifted to the opposite edge upon reopening. I'm using Manjaro with the optional kde-unstable repo packages, Gwenview is currently versioned at 21.04.3.r6650.gb292af50-1. I'm attaching a photo that causes the problem on my end, see if you can reproduce it.
I discovered this issue in current Gwenview a while ago. I use this feature a lot when editing screenshots from my android phone. It happens often, but not for every single image I edit and I haven’t found out yet why that is. Looking at a binary diff of an image and its rotated version, I noticed that the content is completely different. Is Gwenview actually recompressing the whole image‽ I’ve always assumed that it would only change the appropriate orientation tag, because recompression is a bad idea for jpeg in any case. :( Operating System: Arch Linux KDE Plasma Version: 5.23.5 KDE Frameworks Version: 5.90.0 Qt Version: 5.15.2 Kernel Version: 5.16.5-arch1-1 (64-bit) Graphics Platform: X11 Processors: 4 × Intel® Core™ i5-4590 CPU @ 3.30GHz Memory: 31.0 GiB of RAM Graphics Processor: Mesa DRI Intel® HD Graphics 4600
Thank you for the bug report. Unfortunately we were not able to get to it yet. Can we ask you to please check if this is still an issue with Gwenview 25.08.0 (the latest released version)?
Created attachment 184717 [details] Original on left, rotated on right. Yes it is, I just tried it with 25.08.0 on Arch. The amount of “rolling” is actually bigger now than when I first noticed the issue.
Good you follow this up, both developer and tester! Regarding the method to rotate, comment #8, I think id would be a good featue to add a control of weather rotation should only change the orientation tag, or actually rotate the image. That is because I have found some applications/devices do not handle rotation tag correctly, and sometimes it is set wrong.