Bug 459219 - VLC scales wrong when on secondary screen when using "Apply scaling themselves"
Summary: VLC scales wrong when on secondary screen when using "Apply scaling themselves"
Status: RESOLVED WORKSFORME
Alias: None
Product: kwin
Classification: Plasma
Component: wayland-generic (other bugs)
Version First Reported In: git master
Platform: openSUSE Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2022-09-16 15:32 UTC by postix
Modified: 2022-10-16 04:55 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:


Attachments
Screen recording (762.72 KB, video/x-matroska)
2022-09-16 15:32 UTC, postix
Details
kWin Support Info (7.20 KB, text/plain)
2022-09-16 15:33 UTC, postix
Details
Screenshot: VLC with vale unset (242.87 KB, image/png)
2022-09-16 16:02 UTC, postix
Details

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Description postix 2022-09-16 15:32:57 UTC
Created attachment 152110 [details]
Screen recording

STEPS TO REPRODUCE
0. Two screens (2k@100% + 4k@200% primary)
1. Legacy Applications (X11): Apply scaling themselves
2. Open VLC with `QT_SCREEN_SCALE_FACTORS=2 /usr/bin/vlc` on the primary screen
3. Move it to the secondary screen

OBSERVED RESULT
The VLC window looks fine as expected while dragging it to the secondary screen, but once dropped there, it scales too small (like 0.5 for the @100% screen). Please see the screen recording.

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20220914
KDE Plasma Version: 5.26.80
KDE Frameworks Version: 5.98.0
Qt Version: 5.15.5
Kernel Version: 5.19.8-1-default (64-bit)
Graphics Platform: Wayland
Graphics Processor: AMD Radeon RX 580 Series
Comment 1 postix 2022-09-16 15:33:09 UTC
Created attachment 152111 [details]
kWin Support Info
Comment 2 David Edmundson 2022-09-16 15:38:38 UTC
Looks like VLC is trying to be too clever. 

With the value unset what does VLC do? Also what happens on real X11.
Comment 3 postix 2022-09-16 16:02:11 UTC
Created attachment 152117 [details]
Screenshot: VLC with vale unset

(In reply to David Edmundson from comment #2)
> With the value unset what does VLC do? 
Its UI buttons scale too small and it looks the very same on both screen.

> Also what happens on real X11.
Will check that too.
Comment 4 postix 2022-09-16 19:04:35 UTC
> Also what happens on real X11.
Not sure how I gonna test this, because when basically do 
`source ~/development/kde/build/kde/workspace/kwin/prefix.sh && dbus-run-session  ~/development/kde/local/bin/startplasma-x11`
it won't start the plasma session saying
> $DISPLAY is not set or cannot connect to the X server

The var is indeed unset, but setting it to e.g. :0 did resolve it. Maybe I will test it with KDE Neon Unstable instead later.
Comment 5 Bug Janitor Service 2022-10-01 04:49:08 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 6 Bug Janitor Service 2022-10-16 04:55:42 UTC
This bug has been in NEEDSINFO status with no change for at least
30 days. The bug is now closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!