Bug 453864

Summary:	Drawing tablet cursor offsets from actual clicking/hovering position when Global Scaling set to anything other than 100%
Product:	[Plasma] kwin	Reporter:	Tyson Tan <tysontanx>
Component:	input	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	nate, xaver.hugl
Priority:	VHI	Keywords:	regression
Version First Reported In:	5.24.5
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Screenshot of graphics tablet cursor offsets from actual clicking position in Dolphin

Description Tyson Tan 2022-05-16 02:50:55 UTC

When I set the Global scaling to anything other than 100%, my drawing tablet's cursor is not where the actual clicking/hovering position is.

For example, I'm using a Cintiq Pro 24, which is a 4K pen display. When I set the global scaling to 125%, the actual clicking/hovering position of my stylus offsets about 10-20cm lower than the cursor on screen.

I began to notice this bug after the lastest KDE/Qt stack update. But I also only changed the global scaling for the firtst time at the same day, so I couldn't be too sure.

The bug is affecting all KDE apps and Plasma system apps, including Dolphin, Konsole, Systemsettings and such. It doesn't affect Krita's the official appimage build.

Operating System: Arch Linux
KDE Plasma Version: 5.24.5
KDE Frameworks Version: 5.94.0
Qt Version: 5.15.4

Comment 1 Nate Graham 2022-05-16 18:32:48 UTC

Are you using the X11 session or the Wayland session?

Comment 2 Tyson Tan 2022-05-17 01:35:07 UTC

X11

Comment 3 Tyson Tan 2022-05-18 06:49:23 UTC

Created attachment 148939 [details]
Screenshot of graphics tablet cursor offsets from actual clicking position in Dolphin

4K screen, 150% scaling. Notice how the cursor offsets from the dragging area.

I tried on a Plasma Wayland session, it did not have this bug, but tablet support is still pretty broken.

Comment 4 Zamundaaa 2022-05-28 11:51:24 UTC

Works fine here.
As KWin doesn't do any input routing on X11 and the Krita build works fine, I assume it must be a Qt bug