Bug 480486

Summary:	framerate stutters on thumbnail hover
Product:	[Applications] digikam	Reporter:	digikam
Component:	Thumbs-Album	Assignee:	Digikam Developers <digikam-bugs-null>
Status:	REPORTED ---
Severity:	normal	CC:	metzpinguin
Priority:	NOR
Version First Reported In:	8.2.0
Target Milestone:	---
Platform:	Microsoft Windows
OS:	Microsoft Windows
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description digikam 2024-01-29 12:17:41 UTC

SUMMARY
With a high framerate display (144Hz)  and G-SYNC enabled, mouse pointer movement over thumbnails triggers framerate stuttering for about a second. This only happens when transitioning to a thumbnail. This issue wasn't present in 8.0.0.

STEPS TO REPRODUCE
1. Start digikam and wait for albums to load and any scans to finish
2. In thumbnail or preview windows, hover over the menu or  other sidebars and move the mouse pointer quickly in circles to observe normal mouse smoothness/framerate
3. Move pointer over a thumbnail and move pointer in a circle as before, observe duration of slow framerate
4. Move pointer over another thumbnail moving mouse as before and observe framerate

OBSERVED RESULT
When a thumbnail is first hovered over there is about 1 second of slow framerate before normal framerate returns, this happens for each subsequent thumbnail hover.

EXPECTED RESULT
No framerate loss/shift when hovering between thumbnails

SOFTWARE/OS VERSIONS
Windows:  11 Pro  - Version 10.0.22621 Build 22621
Qt Version:  6.6.0

ADDITIONAL INFORMATION
- Switching to fullscreen vs fullscreen and windowed GSYNC application doesn't make any difference
- Trying to lock the framerate causes brief black frames when hovering between thumbnails
- Albums contain both jpg. and CR3. files
- Does not happen when another window is in the foreground

Comment 1 Maik Qualmann 2024-01-29 12:33:06 UTC

Please test the pre-release digiKam-8.3.0 from here:

https://files.kde.org/digikam/

Also test the new "Force use of software OpenGL rendering" option in the digiKam settings under Miscellaneous-> System.
Please report.

Maik

Comment 2 Maik Qualmann 2024-01-29 12:47:20 UTC

I googled a little, other projects noticed something similar, it is an interaction between G-Sync and the new render engine in Qt6. We will probably not be able to change anything at first, unless you try the software OpenGL option.

Maik

Comment 3 digikam 2024-01-29 13:08:26 UTC

Confirmed that it's still present in 8.3.0.
I tried "Force use of software OpenGL rendering", and also removed the profile in the Nvidia control panel for digikam with no effect.
There doesn't seem to be anything forced in the global Nvidia settings other than having G-sync enabled on fullscreen.

Digikam is still usable, just not as smooth. :)

Comment 4 caulier.gilles 2025-04-11 18:13:48 UTC

Hi,

The 8.7.0 pre-release Windows installer from today have been rebuilt from
scratch with Qt 6.8.3, KDE 6.12, OpenCV 4.11 + CUDA support, Exiv2 0.28.5, ExifTool 13.27, ffmpeg 7, all image codecs updated to last version (jxl, avif, heif, aom, etc.).

Please try with this version to see if your problem still reproducible...

https://files.kde.org/digikam/

Thanks in advance
Best regards

Gilles Caulier