SUMMARY When viewing a picture in a maximised window, the transition animation between images is very slow. STEPS TO REPRODUCE 1. Download two *different* sample JPG images from here: https://sample-videos.com/download-sample-jpg-image.php (I used the 15 mb and 30mb sample). 2. Open one of the two downloaded samples in Gwenview. 3. Maximise the windows. 4. Go to the next picture by either clicking on the arrows in the top menu, or by using the keyboard (arrow keys). OBSERVED RESULT The transition animation is not smooth at all. EXPECTED RESULT A smooth transition animation. SOFTWARE/OS VERSIONS Operating System: Fedora Linux 42 KDE Plasma Version: 6.3.5 KDE Frameworks Version: 6.13.0 Qt Version: 6.9.0 ADDITIONAL INFORMATION: - The transition lag is not present when starting gwenview with `QT_QPA_PLATFORM=xcb`. - When using the environment variable mentioned above, it also helps greatly with Bug 430143. - CPU: AMD Ryzen 9 7950X3D - GPU: AMD Sapphire 7900 XTX Nitro+
The workaround mentioned in my first message, `QT_QPA_PLATFORM=xcb`, requires Legacy applications (X11) to be set to: "Scaled by the system" under System Settings -> Display & Monitor .
Thanks for your report and your comment in Bug 430143. So far I wasn't able to reproduce this. Tested in Gwenview 25.04.2 (from Flatpak) and 25.04.2 from 6.4 Beta. I could not exactly reproduce 35% zoom but 36%. Transition from picture to picture is smooth, also to and from the huge pictures. On the next picture it resets the zoom level according to best fit. If you have a different behavior it would help if you could explain how to achieve it. Operating System: Arch Linux KDE Plasma Version: 6.3.91 KDE Frameworks Version: 6.14.0 Qt Version: 6.9.1 Kernel Version: 6.14.10-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 16 × AMD Ryzen 7 5700X3D 8-Core Processor Memory: 32 GiB of RAM (31.3 GiB usable) Graphics Processor: NVIDIA GeForce RTX 2070 SUPER Manufacturer: Micro-Star International Co., Ltd. Product Name: MS-7B85 System Version: 1.0 nvidia-open-dkms 575.57.08-1
I've tried recording a video of the slow transition performance, but due to compression (to stay under the file limit) it's not visible. It seems that on a single monitor setup (2560x1440), the transition animation is a lot slower when scaling is set to 125% or 225% (Applying scaling by themselves under Display & Monitor settings). On 100%, 200% and 300% it's a lot smoother. I notice the same behaviour when it comes to the zoom performance. Changing animations under settings to OpenGL or Software makes no noticeable difference to me. The only thing I can think of is the monitor resolution, as the performance is even worse when connecting a single 3840x2160 monitor. Aside from that, I'm not sure what else is causing different behaviour on my setup. Could it perhaps be the GPU? I'll attach a video of the zoom performance in the next message, as that's visible even with the heavy compression.
Created attachment 182204 [details] Showcase of the zoom performance. Using a single monitor (2560x1440) at 100% scaling.
The video you uploaded was likely intended for bug #430143?
That's correct, I accidentally uploaded it this bug report. Should I upload the recording to Bug 430143?
A video demonstration of this one would be helpful
Created attachment 182291 [details] Showcase of the transition performance. I encoded the video with H.265 instead of H.264, it should be easy to see the slow transition performance now. I've also noticed that switching between pictures is a tad delayed, even with animations set to off.
I can reproduce on my device below - browsing back and forth between two images (both relatively small, ~3 MB), there's a certain window size past which the animation becomes slightly choppy, and below which it feels perfectly smooth (technically maximizing wasn't needed to trigger that change). For what it's worth, on my system the animation performance doesn't differ between Wayland and XWayland. Thanks! Gwenview: 25.07.70 KDE Frameworks: 6.16.0 Qt: Using 6.9.1 and built against 6.9.1 Fedora Linux 42 (KDE Plasma Desktop Edition) (Wayland) Build ABI: x86_64-little_endian-lp64 Kernel: linux 6.14.11-300.fc42.x86_64 KDE Plasma Version: 6.4.80 Processors: 16 × AMD Ryzen 7 7800X3D 8-Core Processor Memory: 32 GiB of RAM (30.4 GiB usable) Graphics Processor 1: NVIDIA GeForce RTX 4070 SUPER