Bug 490420

Summary:	Wrong default scaling factor
Product:	[Plasma] Breeze	Reporter:	robert.kagan3
Component:	Icons	Assignee:	visual-design
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	kainz.a, kde, m
Priority:	NOR
Version First Reported In:	6.1.3
Target Milestone:	---
Platform:	openSUSE
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:
Attachments:	Fusion on the left and Breeze on the right side.png

Description robert.kagan3 2024-07-17 20:44:17 UTC

Created attachment 171745 [details]
Fusion on the left and Breeze on the right side.png

SUMMARY
I am using LXQt and have noticed that the icons appear 1.5 times larger with Breeze compared to Fusion.
I opened an issue on the LXQt GitHub repository, but we suspect that this problem is related to Breeze.

"It should be related to a bug in KDE.

I vaguely remember that, when KDE6 came out, @stefonarch told me that its default scaling was 1.5. Now, Breeze may take it directly from KDE settings (which is a bug), such that, with a scale factor of 2, those icons have a size of 32×2×1.5=96px." (@tsujan)

Issue Link: https://github.com/lxqt/lxqt-panel/issues/2077

STEPS TO REPRODUCE
- I have a 14 inch laptop with a resolution of 3840x2160p, running at 1920x1080p.
- I use the default LXQt session, Fancy Menu and SDDM.
- My font is Roboto Regular 11.
- My font resolution (dpi) is 96.
- My global scaling factor is set to 1.
- QT_SCALE_FACTOR is also set to 1.
- SDDM has the option EnableHiDPI set to false.

OBSERVED RESULT
The icons appear 1.5 times larger with Breeze compared to Fusion.

EXPECTED RESULT
The icons should have the same size.

SOFTWARE/OS VERSIONS
- Breeze: 6.1.3
- LXQt Version: 2.0.0
- Distribution & Version: openSUSE Tumbleweed
- Qt Version: 6.7.2
- liblxqt Version: 2.0.0

ADDITIONAL INFORMATION
See appendix.

Comment 1 David Edmundson 2024-07-18 13:19:22 UTC

The QStyle does define some icon sizes:
QStyle::PM_SmallIconSize
QStyle::PM_LargeIconSize


Nothing seems related to scaling, it's just a different default.