https://bugs.kde.org/show_bug.cgi?id=489016
Bug ID: 489016
Summary: [wayland] Showing and hiding titlebar and frames on a
scaled display will cause XWayland windows to move
diagonally by about 1px every time
Classification: Plasma
Product: kwin
Version: 6.1.0
Platform: Other
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: decorations
Assignee: kwin-bugs-n...@kde.org
Reporter: eamonn...@protonmail.com
Target Milestone: ---
SUMMARY
Toggling the window titlebar and frames of an XWayland application on a scaled
display (I am using 150% scaling on my PC and 140% scaling on my laptop), such
as by using a shortcut that you can hold down to repeat. will cause the window
to shift diagonally by about 1px each time. In my testing this has cause the
window to either move diagonally up and to the left, or diagonally down and to
the right, but other combinations may exist as well. I am not sure what
influences the direction that the windows move, perhaps however the coordinates
are being rounded.
This *only* affects XWayland applications and only if they are windowed and not
maximised. A maximised XWayland application (such as Steam) or a fullscreen
XWayland application (such as a game) is not impacted by this.
Holding down the shortcut is not required for this, but it is the fastest way
to toggle the window decorations and to see visually the movement.
It is worth noting that I only found one XWayland application that was
unaffected, and that was the Steam Client. I thought that maybe this only
affected Qt-based XWayland windows then, but games running via Wine also
exhibit this behaviour (games are my most common XWayland use-case which is the
only reason I mention them).
I could be wrong but perhaps this is related to some fractional scaling
weirdness and the rounding of pixels (which should be fixed with
fractional-scale-v2)? Possibly related in that case: Bug 459373.
STEPS TO REPRODUCE
1. Have an XWayland that has a traditional titlebar and frame, such as the
Dolphin File Manager running with XWayland using `QT_QPA_PLATFORM=xcb dolphin`
a. You can verify when a program is using XWayland with xeyes
2. Have a keyboard shortcut bound to toggle the Window Titlebar and Frame (can
be set under Shortcuts -> KWin -> "Toggle Window Titlebar and Frame")
3. Put the window onto a scaled display.
4. Hide the titlebar and frame, the shortcut will cause the window to drift
OBSERVED RESULT
Many XWayland windows will drift by about 1px each time if you toggle their
window decorations. There is at least one exception, the Steam Client, but
every other tested XWayland window did exhibit this behaviour (including some
KDE apps like Dolphin forced to run with XWayland)
EXPECTED RESULT
XWayland windows should not drift and should behave the same as Wayland
windows.
SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.9.5 Linux Zen
KDE Plasma Version: 6.1.0
KDE Frameworks Version: 6.3.0
Qt Version: 6.7.1
ADDITIONAL INFORMATION
Did not test X11 to see if this is just a bug with X11 in general and not spe
--
You are receiving this mail because:
You are watching all bug changes.
