Bug 502322 - Text artifacts in systemmonitor when using fractional HiDPI scaling
Summary: Text artifacts in systemmonitor when using fractional HiDPI scaling
Status: CONFIRMED
Alias: None
Product: plasma-systemmonitor
Classification: Applications
Component: general (other bugs)
Version First Reported In: 6.3.3
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: KSysGuard Developers
URL:
Keywords: wayland-only
Depends on:
Blocks:
 
Reported: 2025-04-02 14:41 UTC by Alex Sh
Modified: 2025-06-15 04:59 UTC (History)
7 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
screenshot of the bug, all screenshots: https://imgur.com/a/XTSEUYO (39.43 KB, image/png)
2025-04-02 14:41 UTC, Alex Sh
Details

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Description Alex Sh 2025-04-02 14:41:42 UTC
Created attachment 179937 [details]
screenshot of the bug, all screenshots: https://imgur.com/a/XTSEUYO

SUMMARY
Text artifacts are on the default main page of the System monitor when I'm using fractional HiDPI scaling

STEPS TO REPRODUCE
1. Set up fractional HiDPI scaling in the System Settings (for me it was 125%)
2. Open System monitor app
3. Look at the main page

OBSERVED RESULT
Text in the "Apps" section is relatively clear, but has some cursed artifacts

EXPECTED RESULT
Text is clear and looks like text in other sections/pages, or like without scaling, or like on X11, or like in other apps.

SOFTWARE/OS VERSIONS

Linux/KDE Plasma: Arch Linux (EndeavourOS)
KDE Plasma Version: 6.3.3
KDE Frameworks Version: 6.12.0
Qt Version: 6.8.3

ADDITIONAL INFORMATION
My GPU is Intel Alder Lake-P GT1 [UHD Graphics], driver: i915. I've experienced this error on Nvidia on older Plasma versions, but at the moment I can't tell if it occurs now on that hardware. I also see similar artifacts in the screenshot creation interface in Spectacle, but they are harder to capture because they don't always show up; and I use Spectacle to create screenshots. I don't know which component this bug relates to, so I chose an application in which I see it and can describe it. Please move it to the appropriate category.
Comment 1 TraceyC 2025-04-02 22:42:02 UTC
Thanks for the bug report, and the screenshots. They make the problem very easy to see.
I'm not able to reproduce this on Plasma 6.3.3 or git-master. I'll leave this open in case someone else can.
Comment 2 Alex Sh 2025-04-04 14:59:08 UTC
See also: bug 501975, bug 502103
Comment 3 TraceyC 2025-04-07 15:52:29 UTC
(In reply to Alex Sh from comment #2)
> See also: bug 501975, bug 502103

Thanks for those. Bug 502103 is a different issue, and is specific to Kolourpaint.

This looks more related to bug 501975 (which is a duplicate of 499289), which is about font rendering on fractionally scaled displays. 
I'm not sure if the text in the System Monitor app is affected in the same way, so I'll leave this open and linked to that other report.
Comment 4 John Kizer 2025-04-13 04:45:44 UTC
Hi - I think I'm reproducing the same bug at 150% scaling, but just to check - if you resize the System Monitor application window, does the text render correctly at some window sizes?
Comment 5 Alex Sh 2025-04-16 10:45:04 UTC
(In reply to John Kizer from comment #4)
> Hi - I think I'm reproducing the same bug at 150% scaling, but just to check
> - if you resize the System Monitor application window, does the text render
> correctly at some window sizes?

Hey! Sorry for the long respond. I've checked: yes, in resized (not maximized) state I don't have these artifacts. When I maximize window — I see it again. I also managed to accidentally start the system monitor once without this problem at all. But, unfortunately, I can't say what this might relate to 🤷‍♂️
Comment 6 John Kizer 2025-04-16 18:41:29 UTC
Thanks - looks like we're experiencing the same issue then :-) And I am using an NVIDIA card currently, so it doesn't seem specific to certain graphics hardware?
Comment 7 Alex J Green 2025-06-01 04:49:30 UTC
(In reply to John Kizer from comment #4)
> Hi - I think I'm reproducing the same bug at 150% scaling, but just to check
> - if you resize the System Monitor application window, does the text render
> correctly at some window sizes?

Hi – from my observations, the issue occurs even without resizing the window. Simply scrolling the content or moving the window slowly causes the fonts to distort.

At 150% scaling, it looks like the pixels aren't aligning properly with their scaled positions – as if they "miss" their enlarged target spots, which creates a distorted or broken appearance in the text rendering. You might want to try moving the window slowly to see if it becomes more noticeable.

It does not depend on hardware.