| Summary: | Desktop background can be seen while alt+tab-ing between maximized windows | ||
|---|---|---|---|
| Product: | [Plasma] kwin | Reporter: | Albert Astals Cid <aacid> |
| Component: | general | Assignee: | KWin default assignee <kwin-bugs-null> |
| Status: | REPORTED --- | ||
| Severity: | normal | CC: | nate, sandro.jaeckel, wazhai |
| Priority: | NOR | ||
| Version First Reported In: | 5.24.0 | ||
| Target Milestone: | --- | ||
| Platform: | Other | ||
| OS: | Linux | ||
| Latest Commit: | Version Fixed/Implemented In: | ||
| Sentry Crash Report: | |||
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Description
Albert Astals Cid
2022-02-10 22:12:20 UTC
Qt 5.15.kde obviously, sorry for the mental-slip Can you post the output of `qdbus org.kde.KWin /KWin supportInformation`? Can't reproduce it myself. On this computer i can reproduce it *VERY* easily https://ghostbin.com/RULuW/raw (alt-tabbing and alt+shift-tabbing between konsole and firefox will make it happen say 30% of the time). On my other (faster/newer laptop https://ghostbin.com/EFiEo/raw ) I can see it sometimes, but much less often, maybe it's a driver/CPU speed issue? I'm going to try with a much slower one now. Also make sure you use the Plasma 5.24 background, it being so distinctively black and red in places defenitely helps realizing "this should not be here" Does this happen with other task switchers, e.g. breeze? Does kwin also print any warnings in the logs? Yes, it also happens with the breeze switcher. This is what i get from a "clean" kwin_x11 --replace https://ghostbin.com/49Iw5/raw I don't get "new" debug/warnings when the issue happens. As a baseline i disabled the compositor (Alt+Shift+F12) and this problem doesn't happen anymore Cannot reproduce at all on Wayland. I'm not sure it's a regression, this may have been happening for a while, just the new wallpaper is much more intense so seeing it is much more distracting. On Matrix we tracked it to the "highlight window" effect Vlad said if you switch from window A to B, the highlight window effect (enabled by "show selected window" in system settings) will start two animations A: opacity goes from 1 to 0 B: opacity goes from 0 to 1 so desktop background can sneak through And suggested that maybe the highlight window effect could start 0 -> 1 animation first and delay 1 -> 0 animation I'll try to see if i can make that happen and test it myself, though the code in https://invent.kde.org/plasma/kwin/-/blob/master/src/effects/highlightwindow/highlightwindow.cpp is not as easy to understand as i'd like ^_^ After discussing on Matrix, parallel cross fading will always result in this, needs to be sequential, but I don't have enough understanding of the code to be able to work on that, so someone else needs to tackle this. kbroulik: if you have two items ontop of each other with opacity < 1 you will always see through ahiemstra: combining opacity is more like averaging their values rather than adding them up generally, for cross fade animations what you want to do is have the original image at opacity 1 until the end and fade the new image from 0 to 1 on top of that |