Bug 505440 - Plasma popups flash gray when opening or closing over a monochrome background
Summary: Plasma popups flash gray when opening or closing over a monochrome background
Status: RESOLVED FIXED
Alias: None
Product: kwin
Classification: Plasma
Component: effects-overview (other bugs)
Version First Reported In: 6.4.80
Platform: Other Linux
: NOR minor
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords: regression
Depends on:
Blocks:
 
Reported: 2025-06-10 16:02 UTC by Nate Graham
Modified: 2025-07-28 12:59 UTC (History)
0 users

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


Attachments
Dark flashing when opening and closing (3.26 MB, video/webm)
2025-06-10 16:02 UTC, Nate Graham
Details

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Description Nate Graham 2025-06-10 16:02:05 UTC
Created attachment 182153 [details]
Dark flashing when opening and closing

After https://invent.kde.org/plasma/kwin/-/merge_requests/6838 was merged, when any Plasma popup (notification, OSD, panel widget, ToolTipArea) open or closes above a gray, black, or non-colorful background, it flashes gray for a moment, which is somewhat ugly and visually jarring.

See attached screen recording.
Comment 1 Vlad Zahorodnii 2025-06-11 07:10:01 UTC
Git commit 57d2671bb5427dab959ca57b27fb8f78000eb7e6 by Vlad Zahorodnii.
Committed on 11/06/2025 at 07:09.
Pushed by vladz into branch 'master'.

plugins/blur: Make background flash less strong

With the current modulation curve, the background can be more opaque
than the window. Since the contrast effect raises the brightness a bit,
it can result in a flash if the window has dark contents.

This patch changes the modulation curve to `alpha ** 2`, so the
background contents is less strong. There is still a bit of flashing
but it's barely noticeable now. The only downside of this change is
that windows can lose their "background" faster when they are animated,
but in my testing, it is not a really noticeable issue.

M  +1    -3    src/plugins/blur/blur.cpp

https://invent.kde.org/plasma/kwin/-/commit/57d2671bb5427dab959ca57b27fb8f78000eb7e6
Comment 2 Vlad Zahorodnii 2025-07-28 12:59:39 UTC
Git commit 41bdcc52c3d501e352509c5dd19a9cc8d0bc4417 by Vlad Zahorodnii.
Committed on 28/07/2025 at 11:24.
Pushed by vladz into branch 'master'.

plugins/blur: Make background flash less strong

With the current modulation curve, the background can be more opaque
than the window. Since the contrast effect raises the brightness a bit,
it can result in a flash if the window has dark contents.

This patch changes the modulation curve to `alpha ** 2`, so the
background contents is less strong. There is still a bit of flashing
but it's barely noticeable now. The only downside of this change is
that windows can lose their "background" faster when they are animated,
but in my testing, it is not a really noticeable issue.
(cherry picked from commit 57d2671bb5427dab959ca57b27fb8f78000eb7e6)

M  +1    -3    src/plugins/blur/blur.cpp

https://invent.kde.org/plasma/kwin-x11/-/commit/41bdcc52c3d501e352509c5dd19a9cc8d0bc4417