Bug 511170

Summary:	Blur effect when using software brightness is incorrect
Product:	[Plasma] kwin	Reporter:	Błażej Szczygieł <mumei6102>
Component:	effects-various	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED DUPLICATE
Severity:	normal	CC:	pavel23dob, sollacea, xaver.hugl
Priority:	NOR
Version First Reported In:	6.5.0
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Błażej Szczygieł 2025-10-26 17:02:29 UTC

SUMMARY
Blur effect when software brightness is used is incorrect.

STEPS TO REPRODUCE
1. Turn on Blur effect.
2. Disable DDC/CI brightness.
3. Set brightness to very low.

OBSERVED RESULT
Plasma tooltips are brighter or white.

EXPECTED RESULT
Plasma tooltips looks as in 100% brightness, but dimmer.

SOFTWARE/OS VERSIONS
KDE Plasma Version: 6.5.0
KDE Frameworks Version: 6.19
Qt Version: 6.10.0

ADDITIONAL INFORMATION
It's a regressions, on 6.4.5 it looks correctly.  In HDR and 0% brightness tooltips are white and text is also white. On screenshots it looks correctly.

If the blur is enabled and plasma is using basic renderloop, resizing plasma windows flickers to white with full brightness for a short time.

Comment 1 Pavel Dobiáš 2025-10-26 21:06:32 UTC

Same happening for me too.

Comment 2 Zamundaaa 2025-10-27 15:21:24 UTC


*** This bug has been marked as a duplicate of bug 510818 ***

Comment 3 Błażej Szczygieł 2025-11-21 10:47:19 UTC

Still happens in 6.5.3.

Comment 4 Vlad Zahorodnii 2025-11-21 11:12:44 UTC

> It's a regressions, on 6.4.5 it looks correctly

Did you use to disable the background contrast completely in 6.4?

Comment 5 Vlad Zahorodnii 2025-11-21 13:15:26 UTC

Also, out of curiosity, are you in #kwin on matrix? If so, what's your username?

Comment 6 Błażej Szczygieł 2025-11-21 17:06:37 UTC

> Also, out of curiosity, are you in #kwin on matrix? If so, what's your username?

Not yet, I have to finally login there :D

> Did you use to disable the background contrast completely in 6.4?

I don't have 6.4 anymore, but tested on 6.3.6: yeah it seems to be contrast issue - with contrast it's wrong on 6.3, without contrast it's correct (most likely I had contrast turned off in 6.4, too).

Comment 7 Zamundaaa 2025-12-15 12:40:01 UTC

*** Bug 513127 has been marked as a duplicate of this bug. ***

Comment 8 Zamundaaa 2026-01-08 23:53:12 UTC


*** This bug has been marked as a duplicate of bug 502651 ***