https://bugs.kde.org/show_bug.cgi?id=523864
Bug ID: 523864
Summary: Stylus cannot start strokes on GNOME/Wayland unless
XWayland is bypassed (QT_QPA_PLATFORM=wayland) — no
tip-down event received
Classification: Applications
Product: krita
Version First 5.3.3
Reported In:
Platform: Ubuntu
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: Tablets (tablet issues are only very rarely bugs in
Krita!)
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
SUMMARY
On GNOME/Wayland, Krita picks up stylus motion and pressure through
XWayland, but never gets a tip-down/press event — so you can move the
cursor with the pen, but can't actually start a stroke. Forcing native
Wayland with QT_QPA_PLATFORM=wayland fixes it completely. This looks like
the same XWayland-default issue discussed in bug 379174, but that report
is 9 years old and covers several different symptoms (Art Pen rotation,
general tablet support, etc.), so I'm filing this separately with a
focused, easily reproducible case.
STEPS TO REPRODUCE
1. Run a GNOME/Wayland session (Ubuntu 26.04 — note that the GNOME-on-Xorg
session doesn't exist anymore on this release).
2. Launch Krita normally.
3. Touch the tablet with the stylus and try to draw on a canvas.
OBSERVED RESULT
- The cursor stays a normal system arrow instead of switching to Krita's
brush cursor.
- Tablet Tester shows no tablet events at all when drawing with the
stylus alone.
- The stylus moves the cursor fine, but can't start a stroke.
- Workaround I found: if I hold down the left mouse button first, and
then touch the tablet with the stylus, Krita immediately starts drawing
with full pressure sensitivity. Releasing the mouse button stops the
stroke right away. This suggests Krita is receiving motion and pressure
from the stylus via XWayland, but not a proper tip-down event, unless a
real mouse button is already held down.
EXPECTED RESULT
The stylus alone should be able to start and end strokes, same as it does
in other applications on the same machine.
SOFTWARE/OS VERSIONS
- Ubuntu 26.04 LTS, GNOME (Wayland-only; GNOME-on-Xorg was removed
upstream starting with GNOME 49)
- Reproduced on Krita 5.3.3 (AppImage), Krita 5.2.x (Snap), Krita 6.0
(stable), and Krita 6 Beta — so this isn't tied to one specific version
- Tablet: XP-Pen Deco 01 v2, USB ID 28bd:0002
- evtest confirms the kernel sees everything correctly (BTN_TOUCH,
ABS_PRESSURE, ABS_X/Y, tilt)
- The vendor's own XP-Pen driver test area receives stylus input just
fine, and Xournal++ handles the same stylus correctly out of the box —
so the tablet, driver, and kernel side all seem fine
ADDITIONAL INFORMATION
Running `QT_QPA_PLATFORM=wayland krita` fixes the issue completely for
me — tablet cursor shows up, Tablet Tester picks up events, and drawing
works with full pressure, no need to hold the mouse button anymore.
This lines up with a June 2026 comment on bug 379174 from a Wacom rep,
who ran into the same XWayland-default root cause (in their case it broke
Art Pen rotation) and used the same fix.
Since Ubuntu 26.04 (and other GNOME 49+ distros) dropped the
GNOME-on-Xorg session entirely, "just switch to Xorg" isn't really an
option for GNOME users anymore, which makes proper native Wayland tablet
support more important going forward.
Would it make sense for Krita to default to QT_QPA_PLATFORM=wayland on
Wayland sessions where the native Qt Wayland plugin is available, instead
of defaulting to XWayland?
SEE ALSO
https://bugs.kde.org/show_bug.cgi?id=379174
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