Bug 485063

Summary: When resizing Gwenview with a fractional screen scale factor, images lose vertical/horizontal lines of pixels
Product: [Applications] gwenview Reporter: nyanpasu64 <nyanpasu64>
Component: generalAssignee: Gwenview Bugs <gwenview-bugs-null>
Status: RESOLVED WORKSFORME    
Severity: normal CC: idontfeelcomfygivingyoumyemail
Priority: NOR    
Version First Reported In: 24.02.1   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Screenshot of Gwenview with missing pixels in the image shown at 100%.

Description nyanpasu64 2024-04-05 06:15:19 UTC 
Created attachment 168169 [details]
Screenshot of Gwenview with missing pixels in the image shown at 100%.

SUMMARY
When I open Gwenview on a monitor set to a fractional scale factor, images shown at 100% are often missing rows/columns of pixels.

STEPS TO REPRODUCE
1. Set a monitor to a fractional scale factor (eg. 125% or 150%). The issue occurs on both X11 and Wayland. On X11, the same result happens with a font scale factor (though this didn't cause issues on KDE 5/Qt5).
2. Open an image on that monitor (most visible with screenshots).
3. Resize the window to make missing pixels appear and disappear.

OBSERVED RESULT
Rows and columns of the image disappear.
- You'll probably want to start with a screenshot taken on X11, because Bug 483876 causes Spectacle itself to capture blurry images of Gwenview. This also prevents me from taking a picture of this bug on Wayland.

EXPECTED RESULT
The image is shown pixel-perfectly on-screen.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.0.3
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.3
Kernel Version: 6.7.4-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 5600X 6-Core Processor
Memory: 15.5 GiB of RAM
Graphics Processor: AMD Radeon RX 570 Series
Manufacturer: Gigabyte Technology Co., Ltd.
Product Name: B550M DS3H

ADDITIONAL INFORMATION
Comment 1 A Linux User 2025-08-22 19:02:01 UTC 
Cannot reproduce on Wayland, Gwenview 25.08, 150% scaling.
Comment 2 A Linux User 2025-08-22 19:02:18 UTC 
Is this still an issue for you?
Comment 3 nyanpasu64 2025-08-25 03:36:09 UTC 
The bug no longer seems to appear on Wayland after logging out/in at 125% scale? Though I'm on a different machine than last time.

Operating System: Fedora Linux 42
KDE Plasma Version: 6.4.4
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.1
Kernel Version: 6.15.10-200.fc42.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-8559U CPU @ 2.70GHz
Memory: 16 GiB of RAM (15.5 GiB usable)
Graphics Processor: Intel® Iris® Plus Graphics 655
Manufacturer: Intel(R) Client Systems
Product Name: NUC8i7BEH
System Version: J72992-303