Bug 481322 - When switching tasks, "Hightlight Window" effect isn't ideal for maximized windows
Summary: When switching tasks, "Hightlight Window" effect isn't ideal for maximized wi...
Status: CONFIRMED
Alias: None
Product: kwin
Classification: Plasma
Component: effects-various (show other bugs)
Version: 6.2.2
Platform: Other Linux
: NOR minor
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords: usability
: 493138 (view as bug list)
Depends on:
Blocks:
 
Reported: 2024-02-14 13:36 UTC by Yevhen Popok
Modified: 2024-10-23 16:37 UTC (History)
2 users (show)

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


Attachments
Screencast demonstrating flickering with the Hightlight Window effect (1.22 MB, video/webm)
2024-02-14 13:36 UTC, Yevhen Popok
Details
1-Fade ignores window in focus | 2-Except when both are in focus. (2.69 MB, video/mp4)
2024-09-17 01:21 UTC, Fernando M. Muniz
Details

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Description Yevhen Popok 2024-02-14 13:36:31 UTC
Created attachment 165819 [details]
Screencast demonstrating flickering with the Hightlight Window effect

SUMMARY
"Highlight Window" effect makes possible to hightlight windows while hovering over taskbar entries. When user selects some window (by hover over taskbar window entry or by switching with tasks with Alt+Tab), other windows temporally hide, so user can focus on a particular window.  "Highlight Window" doesn't hide other elements (e.g. desktop, panel, widgets), and this effect works really well when user has a only floating windows.
However,  when user switches between maximized window, there's always a distracting side effect. For a very short time highlighted window becomes semi-transparent so user sees desktop, then window becomes opaque again.

STEPS TO REPRODUCE (please also see screencast in attachment)
1. Open and maximize several windows
2. Press and hold "Alt" key
3. While holding "Alt", slowly press "Tab" several times to switch between windows

OBSERVED RESULT
After temporal switch to the Task Switcher task, there's a brief flickering (highlighted window becomes semi-transparrent showing desktop)

EXPECTED RESULT
I don't need to briefly see desktop when I switch to the maximized window.
I also think that option to not hide other window might improve experience with tiled windows for some users.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma:  Fedora Kinoite Rawhide (40)
KDE Plasma Version: 5.93.0
KDE Frameworks Version: 5.249.0
Qt Version: 6.6.1

ADDITIONAL INFORMATION
It's not Plasma 6 or Wayland regression. I have the same issue on Plasma 5.27
Also, as you can see from the screencast, highlight of the taskbar entries can be smoother sometimes. There's still some unwanted flickering but transition goes from the window below, not from desktop (as in the case with the Task Switcher).
Comment 1 Nate Graham 2024-02-15 17:09:27 UTC
Agreed, the effect isn't really ideal for large maximized windows.
Comment 2 Zamundaaa 2024-09-16 19:55:14 UTC
*** Bug 493138 has been marked as a duplicate of this bug. ***
Comment 3 Fernando M. Muniz 2024-09-17 01:21:48 UTC
Created attachment 173748 [details]
1-Fade ignores window in focus | 2-Except when both are in focus.

Reposting my issue since it's a bit different.

As the attachment shows, when only one window is in focus (tomato), and you hover the mouse over an window not in focus (potato), for some odd reason the fade effect roughly flashes your desktop, then the window starts fading in.
In the later part, when both windows are in focus, the fade effect works smoothly between them.

Not only its visually inconsistent, it could cause a headache if you have photosensitivity.
I believe the issue is that the fade effect ignores window in focus when another is not in focus, thus flashing the desktop as failsafe.
Comment 4 Fernando M. Muniz 2024-09-26 16:35:53 UTC
To better explain the last part; I believe that the effect is for some reason not noticing that there are open or maximized windows in sight, so it just shows the desktop are during the effect. 

I believe that making the effect recognize and show the windows that are in front of the desktop (or maximized) during the effect would solve this issue.
Comment 5 Fernando M. Muniz 2024-09-26 17:04:45 UTC
The effect recognizes windows in focus, but ignores the ones that aren't in focus but are visibly in front of the desktop.