Bug 480021

Summary: With fractional scaling, dragging a wobbly window makes it blurry until the drag is released
Product: [Plasma] kwin Reporter: Nate Graham <nate>
Component: generalAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED DUPLICATE    
Severity: minor CC: d_debnath
Priority: NOR    
Version First Reported In: master   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Screen recording

Description Nate Graham 2024-01-18 22:36:14 UTC
Created attachment 165024 [details]
Screen recording

Today's Plasma 6 Wayland git master.

When a screen is using a fractional scale factor, clicking and dragging on an of its windows makes the windows visibly blurry until the drag is completed. It happens even if you click-and-hold on the window's titlebar and don't drag it anywhere. Screen recording attached.

The DPI of the screen determines how noticeable this is. With a 1080p screen at 110% or 125% scale, the effect is extremely noticeable. With a 4k screen at 225% scale, the effect is almost imperceptible--though still clearly happening if you look closely.

ADDITIONAL INFORMATION
The issues does not happen with integer scale factors such as 100% and 200%.

Fascinatingly, while taking a screen recording, the issue only happens when the window is being actively dragged; it stops reproducing in the simple case where the titlebar is clicked-and-held but the window isn't actually moved.
Comment 1 D. Debnath 2024-01-24 14:33:38 UTC
This appears to be related (according to the developer): https://github.com/matinlotfali/KDE-Rounded-Corners/issues/149
Comment 2 Nate Graham 2024-01-26 14:46:50 UTC
Only happens when the Wobbly Windows effect is active!
Comment 3 Nate Graham 2024-01-26 15:17:00 UTC
Ah, it's a simple recurrence of Bug 461283.

*** This bug has been marked as a duplicate of bug 461283 ***