Bug 406746 - XRender renders some things with too much transparency
Summary: XRender renders some things with too much transparency
Status: RESOLVED NOT A BUG
Alias: None
Product: kwin
Classification: Plasma
Component: compositing (show other bugs)
Version: 5.15.4
Platform: Neon Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-04-21 21:23 UTC by Wyatt Childers
Modified: 2019-04-22 16:49 UTC (History)
1 user (show)

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


Attachments
Calendar displaying with too much transparency (30.71 KB, image/png)
2019-04-22 16:29 UTC, Wyatt Childers
Details
Calendar displaying with the correct amount of transparency (57.94 KB, image/png)
2019-04-22 16:29 UTC, Wyatt Childers
Details

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Description Wyatt Childers 2019-04-21 21:23:54 UTC
SUMMARY
For whatever reason XRender occasionally renders the start menu and other "panel pop-ups" as much more transparent than OpenGL.

STEPS TO REPRODUCE
I don't know exactly how to reproduce this consistently yet, aside from just running under XRender.

OBSERVED RESULT
The "panel pop-ups" are much much more transparent, almost completely so.

EXPECTED RESULT
The "panel pop-ups" should be the same darkness as rendering under OpenGL.

ADDITIONAL INFORMATION
Kernel version: 4.15.0-1024-oem
NVidia binary driver: 415
Comment 1 Vlad Zahorodnii 2019-04-21 21:28:44 UTC
Panels look more opaque because of blur and background constrast effect, both require OpenGL.
Comment 2 Wyatt Childers 2019-04-21 21:35:46 UTC
(In reply to Vlad Zagorodniy from comment #1)
> Panels look more opaque because of blur and background constrast effect,
> both require OpenGL.

I believe there's something else going on here. As an example, when I wrote this bug it was occurring, however, at the present time still using XRender my "panel pop-ups" (I really don't know what to call them haha), are the proper transparency.

It's an intermittent issue.
Comment 3 David Edmundson 2019-04-21 22:20:38 UTC
>Panels look more opaque because of blur and background constrast effect, both require OpenGL.

That's true, but plasmashell does know when blur and contrast effect are running and switch to a different more opaque version. 

If OP has a transparent panel it means something along that path isn't working. Either from kwin, in plasma-framework or in the theme.
Comment 4 Vlad Zahorodnii 2019-04-21 22:36:00 UTC
(In reply to David Edmundson from comment #3)
> That's true, but plasmashell does know when blur and contrast effect are
> running and switch to a different more opaque version. 
Hmm, if compositing is turned off, it makes sense to draw opaque panels. Though I don't think such thinking applies when using XRender rendering backend. What if you actually want transparent panels? :)
Comment 5 Vlad Zahorodnii 2019-04-21 22:36:58 UTC
.. but I agree that such aspects have to be controlled by the desktop theme.
Comment 6 Wyatt Childers 2019-04-21 22:42:59 UTC
(In reply to Vlad Zagorodniy from comment #4)
> (In reply to David Edmundson from comment #3)
> > That's true, but plasmashell does know when blur and contrast effect are
> > running and switch to a different more opaque version. 
> Hmm, if compositing is turned off, it makes sense to draw opaque panels.
> Though I don't think such thinking applies when using XRender rendering
> backend. What if you actually want transparent panels? :)

Well, compositing is enabled, through XRender. I think you're miss understanding a bit.

So, I'm specifically talking about "panel pop-ups"/pop overs (things like clicking on the time to see the dates in the month, the part the pops up when you click the time).

There are 3 cases:
- Composition on working correctly:
  Month view is rendering correctly, with the correct opacity/transparency, just like they would on OpenGL, blurred, and simi transparent. 
- Compositing on but broken:
  Month view is being rendered wayyyy too transparent, almost like a glass theme, rather than breeze. 
- Compositing off: 
  Moth view is 100% opaque, no transparency.

This issue is about the second case, where breeze is being rendered as if it were a glass theme sometimes under XRender, never happens under OpenGL.
Comment 7 David Edmundson 2019-04-21 22:52:39 UTC
Can you include some screenshots.

It'll probably be a plasmashell cache issue.
Comment 8 Wyatt Childers 2019-04-21 23:43:11 UTC
(In reply to David Edmundson from comment #7)
> Can you include some screenshots.
> 
> It'll probably be a plasmashell cache issue.

I'll update the issue with a screenshot of the broken state as soon as it occurs again. 

It's intermittent, and has been occurring for quite some time. I switched to an nvidia card, and then switched to XRender from OpenGL as a workaround for https://bugs.kde.org/show_bug.cgi?id=353983. 

This issue is cosmetic, but annoying lol.
Comment 9 Wyatt Childers 2019-04-22 16:29:20 UTC
Created attachment 119565 [details]
Calendar displaying with too much transparency
Comment 10 Wyatt Childers 2019-04-22 16:29:48 UTC
Created attachment 119566 [details]
Calendar displaying with the correct amount of transparency
Comment 11 Wyatt Childers 2019-04-22 16:31:23 UTC
I've attached two images, one correct, one incorrect. I switched to OpenGL briefly to get the correct look. I feel like I've seen it even more transparent than what it is in the broken image I uploaded, but you can definitely tell there's a rendering discrepancy.
Comment 12 Wyatt Childers 2019-04-22 16:49:59 UTC
(In reply to Vlad Zagorodniy from comment #1)
> Panels look more opaque because of blur and background constrast effect,
> both require OpenGL.

Actually I think your assessment here might be the right one. The variation in darkness I'm noticing might just be in my head/based on what's behind the calendar...

Part of what tricked me I think is my desktop background is dark, so when you have a dark desktop background, and a very bright window the contrast between the panel and the calendar is quite striking. When you have a dark window, the contrast isn't nearly as striking.

Thus the dark window case makes it look like it's working, the light window makes it look like it's broken.

Sorry for wasting your time.