Bug 258663

Summary:	Shadows opacity doesn't change with window opacity.
Product:	[Plasma] kwin	Reporter:	tony <lorefice2>
Component:	compositing	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED FIXED
Severity:	normal
Priority:	NOR
Version:	4.3.2
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:
Attachments:	screenshot that shows the problem

Description tony 2010-12-03 11:26:05 UTC

Created attachment 54027 [details]
screenshot that shows the problem

Version:           4.3.2 (using KDE 4.5.4) 
OS:                Linux

When a decoration doesn't provides it's own shadows or the user set it to use the shadows from the shadow effects, the shadow is always visible, even if the window is fully translucent.
The problem is evident using xrender backend (the shadow is fully visible), but is partially triggered when using opengl backend; in that case only the part of tha shadow that is not covered from the window itself remains visible.

Reproducible: Didn't try

Steps to Reproduce:
- Activate desktop effects and set xrender backend

- Activate shadow effect,set the shadow opacity to a high value (90...100) just to make the problem evident and set the shadow color to black.

- Choose a window decoration that doesn't provides it's own shadows, like plastic.

- open a window

- change the window opacity to a very low value

Actual Results:  
- With xrender backend you will see a black block instead of the window
- with poengl backend you will see a black square on the window edges


Expected Results:  
the shadow should follow the window alpha value

Video that shows the problem 
http://www.youtube.com/watch?v=ZY5j2Losdgo

Comment 1 Thomas Lübking 2010-12-03 14:34:12 UTC

built in shadows are imperformant and partially broken, try this replacement.
http://kde-apps.org/content/show.php/BeShadowed?content=121607

reminds me that we'll have to finally decide on the further shadow strategy (entirely deco or external) for 4.7

Comment 2 Martin Flöser 2011-01-31 22:06:20 UTC

Git commit 3b8984d630cc6dc655a171fa9c0f7e74e9ee3c61 by Martin Gr����lin.
Pushed by graesslin into branch 'graesslin/kwin-cleanup'.

Remove Shadow Effect.

The shadow effect is known to be broken since at least 4.5.
It is unfortunately in a state which makes it difficult to maintain
and the architecture has some serious drawbacks. Therefore it is the
best solution to replace the effect with a new and better
implementation. For more information about the new implementation
please see the discussion on KWin mailinglist:
http://lists.kde.org/?l=kwin&m=129607406517609&w=2

This also "fixes" all existing bug reports about the shadow effect.
Most of the bugs will really be fixed when the new shadow system is
implemented, if not it is a new bug and a new report should be created
for it.

Please excuse that we go this unnormal approach to mark bugs as
fixed with code removal.
BUG: 164084
BUG: 160948
BUG: 189241
BUG: 229164
BUG: 258663
BUG: 216709
BUG: 243890
FIXED-IN: 4.7.0

M  +0    -1    kwin/effects/CMakeLists.txt     
M  +0    -7    kwin/effects/configs_builtins.cpp     
D  +0    -31   kwin/effects/shadow/CMakeLists.txt     
D  +0    -786  kwin/effects/shadow/shadow.cpp     
D  +0    -166  kwin/effects/shadow/shadow.desktop     [TRAILING SPACE] [TRAILING SPACE]
D  +0    -102  kwin/effects/shadow/shadow.h     
D  +0    -128  kwin/effects/shadow/shadow_config.cpp     
D  +0    -91   kwin/effects/shadow/shadow_config.desktop     
D  +0    -57   kwin/effects/shadow/shadow_config.h     
D  +0    -258  kwin/effects/shadow/shadow_config.ui     
D  +0    -70   kwin/effects/shadow/shadow_helper.h     
M  +0    -4    kwin/kcmkwin/kwincompositing/main.cpp     
M  +9    -20   kwin/kcmkwin/kwincompositing/main.ui     

http://commits.kde.org/a5d5b61a/3b8984d630cc6dc655a171fa9c0f7e74e9ee3c61