Bug 483359

Summary:	UI Glitches on Mouse/Tablet movements under Plasma 6 Wayland
Product:	[Applications] krita	Reporter:	HPetrus <haigpetrus>
Component:	General	Assignee:	Krita Bugs <krita-bugs-null>
Status:	RESOLVED LATER
Severity:	normal	CC:	halla, mobile.harvey, nicolas.fella
Priority:	NOR	Keywords:	qt6
Version First Reported In:	5.2.2
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description HPetrus 2024-03-12 17:29:34 UTC

SUMMARY
***
UI Glitches on Mouse/Tablet movements under Plasma 6 Wayland.  Cursor doesn't conform to brush shape outline.  The UI glitches out and flashes on most movements using either mouse or tablet.  * Can't confirm if the behaviour is the same on any other brand of graphics card, other than Nvidia.
***


STEPS TO REPRODUCE
1. Log in to a Plasma 6 Wayland session
2. Start Krita 5.2.2 and create a new canvas to paint on
3. Move the stylus/mouse around and watch the UI glitch out

OBSERVED RESULT
Overall UI glitches/flashes and cursor appears to be either a text cursor or other unrelated cursor.

EXPECTED RESULT
Stable UI and accurate cursor, as set in settings.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma:  6.0.1
(available in About System)
KDE Plasma Version:  6.7.9-arch1-1 (64-bit)/6.0.1
KDE Frameworks Version:  6.0.0
Qt Version: 6.6.2

ADDITIONAL INFORMATION
This happens on all Nvidia+Wayland combos QT6.  Cannot confirm that this bug is the same on other GPU combos.

Comment 1 Nicolas Fella 2024-03-12 18:19:31 UTC

This is likely caused by https://gitlab.freedesktop.org/xorg/xserver/-/issues/1317, i.e. an NVidia driver problem

Comment 2 HPetrus 2024-03-12 19:43:23 UTC

(In reply to Nicolas Fella from comment #1)
> This is likely caused by
> https://gitlab.freedesktop.org/xorg/xserver/-/issues/1317, i.e. an NVidia
> driver problem

I tried disabling glamor with the environment variable.  It didn't do the trick, unfortunately.  Not sure this is the problem.  Feels more like a QT5 and Wayland issue, but I can't be sure.

Comment 3 HPetrus 2024-03-17 04:13:29 UTC

Is there a specific way to apply XWAYLAND_NO_GLAMOR=1 before running krita as an appimage, other than export XWAYLAND_NO_GLAMOR=1?

I ask because when I do it this way, it makes no difference whatsoever.

Comment 4 Nick 2024-03-19 16:51:27 UTC

Tried this on Neon on a stock Thinkpad (Intel graphics) and cannot see this issue. Possibly NVIDIA specific?

Comment 5 HPetrus 2024-03-23 04:09:07 UTC

(In reply to Nick from comment #4)
> Tried this on Neon on a stock Thinkpad (Intel graphics) and cannot see this
> issue. Possibly NVIDIA specific?

Most definitely Nvidia specific.  Works on my AMD GPUs without real problems (thus far).  However, adding the NVidia XWAYLAND_NO_GLAMOR=1 environment variable doesn't seem to help at all, as some posts have recommended as a solution.  I'm using the appimage of Krita 5.2.2.  Does the environment variable have to be set in a different way than the usual methods?  Either way, only Krita is doing this.  All other apps are glitch-free in the UI.

Comment 6 Nick 2024-03-23 06:55:45 UTC

Ok. I’m hoping someone with an NVIDIA card can try to duplicate this one to confirm.

Comment 7 Halla Rempt 2024-03-23 19:08:56 UTC

Krita only works with xwayland: there is no native wayland support yet, and probably won't be until we port Krita to Qt6.

Comment 8 Nicolas Fella 2024-03-23 19:25:34 UTC

But the reporter (and anyone else reporting bugs about using Krita on Plasma Wayland) is already using Krita in XWayland mode.

In fact https://gitlab.freedesktop.org/xorg/xserver/-/issues/1317 affects most/all XWayland apps on Nvidia, it wouldn't manifest if Krita was running in Wayland native mode.

I perfectly understand that running Wayland-native is out of scope for now, but you can't just dismiss any report from Wayland users by default

Comment 9 Halla Rempt 2024-03-24 09:42:21 UTC

Resolved/later isn't a dismissal; it means we will look into this at a later date.