Bug 398648

Summary: Magic Lamp minimize doesn't apply Blur
Product: [Plasma] kwin Reporter: Kristopher Ives <kristopher.ives>
Component: effects-variousAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED INTENTIONAL    
Severity: normal    
Priority: NOR    
Version First Reported In: 5.13.90   
Target Milestone: ---   
Platform: Neon   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Kristopher Ives 2018-09-15 01:23:48 UTC 
When using Magic Lamp minimize effect the Blur effect disappears during the animation in Konsole.

How to reproduce bug:

1. Enable Magic Lamp minimize effect
2. Enable Blur desktop effect
3. Use Breeze with Blur option
4. Open Konsole
5. Minimize Konsole

What happens:

Blur goes away.

What should happen:

Blur should stay while the Magic Lamp minimize animation plays.
Comment 1 Vlad Zahorodnii 2018-09-15 06:50:57 UTC 
Technically, that's not possible.

The blur effect operates on rectangular region, while the Magic lamp effect transforms windows.

Sorry, I mark it as WONTFIX.
Comment 2 Vlad Zahorodnii 2018-09-15 07:30:52 UTC 
Okay, maybe, it's possible to blur background behind transformed windows. I think the stencil test would be useful in this case.
Comment 3 Vlad Zahorodnii 2018-09-15 10:56:36 UTC 
Well, no, it's not possible.

* Windows have to specify what region KWin has to blur (e.g. blur behind a sidebar, etc);
* If a window has been transformed, KWin has somehow to transform the region too;
* ... and here lies the root of the problem: effects are free to add and remove windows quads, rotate them, etc. So, given the list of window quads, the Blur effect can't figure out what transformation has been apply to them.