Decoration artifact on hovering

[kupiqu]

Please see the attached screenshot:

No idea where these artifacts come from. They seem to happen randomly, always on hovering, and then stay there. This happens for both active and inactive windows. The number of buttons affected seems quite random too, sometimes they affect just one button (like in the screenshot), sometimes 2 or 3 consecutive buttons.

It could be an upstream bug in breeze, kwin or qt, but somehow I failed to reproduce the issue in breeze.

[tsujan]

Can't reproduce, although I only use BreezeEnhanced.

Are you sure you've compiled it against the same version of KWin? V5.14 shouldn't be compiled with older KWin versions.

[tsujan]

@trmdi Sorry to bother you! Can you reproduce this issue?

[kupiqu]

Yes, I compile BreezeEnhanced against plasma 5.14

It may be driver dependent, perhaps?

[tsujan]

It may be driver dependent, perhaps?

I don't think so.

Is button spacing 6px in your case? Maybe you could attach ~/.config/breezerc as a zip file here for me to test it later.

[kupiqu]

[Common]
OutlineCloseButton=false
ShadowStrength=89

[Style]
ScrollBarAddLineButtons=0
ScrollBarSubLineButtons=0
WindowDragMode=WD_MINIMAL

[Windeco]
ButtonHPadding=4
ButtonSpacing=0
DrawBackgroundGradient=false
DrawSizeGrip=false
DrawTitleBarSeparator=false
TitleAlignment=AlignRight
TitleBarFont=Cabin [IMPA],10,-1,5,50,0,0,0,0,0
matchColorForTitleBar=false

[tsujan]

Thanks! I'll test it as soon as I find some time -- being very busy right now.

[kupiqu]

thank you

[tsujan]

I tested with your configuration but everything was OK. I wasn't able to find anything in the code that might cause the problem you described: ~90% of the code is that of Breeze and a simple animation shouldn't cause this. If your driver had a problem, you would see similar effects elsewhere (do you?).

So, for now, the only things that come to my mind are that you might want (1) to test with another KDE color scheme or (2) to recompile BreezeEnhanced and restart KWin.

I'll keep this open to see if others encounter it or if something else comes to my mind.

[trmdi]

Sorry, I don't see any problem with that screenshot ???

[tsujan]

A part of the background of the button at the middle is transparent. I've never seen that here.

[trmdi]

Do you mean the blue border around the middle buton ? I've never seen that too.
@kupiqu Did you try turning off the vsync or change the openGL version in SystemSetting > Compositor?

[tsujan]

Do you mean the blue border around the middle buton ? I've never seen that too.

Yes. I think if there is a problem with grahic driver or vsync, @kupiqu should see similar issues in other places too.

[kupiqu]

I think it may be driver-dependent, although I didn't notice any issue elsewhere. Changing Vsync didn't help, neither modifying the OpenGL version, but I don't see the artifacts when I instead use XRender.

It all seems to indicate this is an upstream issue, so think I'll close the issue for now while I explore the root cause further...

Thank you @tsujan and @trmdi for your feedback!

[ripefig]

@tsujan I can reproduce this. This happens when the blur desktop effect is enabled and happens more frequently when you use window shading. Shade a window (I have unshade on hover too) and you should see this. I have Open GL 2.0 and integrated graphics.

Maybe make a version without transparency? That seems to be cause.

[tsujan]

@ripefig, thanks for your feedback! Now, I really think this may be related to the graphic driver/settings because I've NEVER seen it here. I can't think of anything in BreezeEnhanced that might cause it: the animation was already there; I just made use of it. But the quality of the blur effect is highly dependent on the graphic driver/settings.

That being said, I keep it in mind. Please let me know if it disappears with a KDE/KWin upgrade or a change in graphic driver/settings.

[kupiqu]

I really think this may be related to the graphic driver

I agree

EDIT: Or a bug in the graphic driver, or a bug in kwin

[tsujan]

or a bug in kwin

That's quite possible. In 2017, I couldn't use KWin because it was so lagging, while I had a powerful computer. I reported the problem but no solution was found. A year later, the problem was completely gone after multiple upgrades. Since then, I use nothing but KWin.

[kupiqu]

That's quite possible. In 2017, I couldn't use KWin because it was so lagging, while I had a powerful computer. I reported the problem but no solution was found. A year later, the problem was completely gone after multiple upgrades. Since then, I use nothing but KWin.

Reminder to ourselves (/me and @ripefig): we should check this out in wayland...

[kupiqu]

Reminder to ourselves (/me and @ripefig): we should check this out in wayland...

I do think it's a kwin bug, no need to go wayland actually, because exactly the same animations in the applet-window-buttons never create such artifacts

[kupiqu]

I filled a bug in kde about this:
https://bugs.kde.org/show_bug.cgi?id=401492

[trmdi]

But I guess it would be very difficult to make they test 3rd party plugins. Furthermore, not everyone has this bug. You have to find a reliable way to reproduce it.

[kupiqu]

well, I guess it depends on how much evidence we report suggesting that the issue is in kwin (even though it is hidden by the fact that vanilla breeze does not have button animations), and mentioning about plasma, where the same animations work fine seems to indicate so.

[trmdi]

@kupiqu @ripefig
Did you try some workarounds in this? https://wiki.archlinux.org/index.php/intel_graphics#Troubleshooting

Also, there is a note there:

Note: Some (Debian & Ubuntu, Fedora, KDE) recommend not installing the xf86-video-intel driver, and instead falling back on the modesetting driver for fourth generation and newer GPUs.

[kupiqu]

But I guess it would be very difficult to make they test 3rd plugins. Furthermore, not everyone has this bug. You have to find a reliable way to reproduce it.

I can reproduce it all the time in my system. To reproduce it, you need intel+opengl, but yes, most likely not all intel+opengl cause the artifacts. Added more info to kde bug...

[kupiqu]

Did you try some workarounds in this? https://wiki.archlinux.org/index.php/intel_graphics#Troubleshooting

I took a look but that is incompatible with xserver-xorg-video-intel-native-modesetting, that is i915 integrated with the linux kernel which seems to be recommended by ubuntu and intel

I did upgrade the kernel from 4.15 to 4.18 to see if there was any improvement, but no luck

[trmdi]

I took a look but that is incompatible with xserver-xorg-video-intel-native-modesetting, that is i915 integrated with the linux kernel which seems to be recommended by ubuntu and intel

I did upgrade the kernel from 4.15 to 4.18 to see if there was any improvement, but no luck

Did you try xserver-xorg-video-intel instead of the recommended one?
(I'm not sure about the name, but I mean the non-modesetting one)

[kupiqu]

Did you try xserver-xorg-video-intel instead of the recommended one?

No, I didn't want to mess with it. At least not at this time... But I may try it out, will see.

[trmdi]

Did you try xserver-xorg-video-intel instead of the recommended one?

No, I didn't want to mess with it. At least not at this time...

I've just checked, I'm using it.

[kupiqu]

I've just checked, I'm using it.

Which one, Kernel or Xorg?

[ripefig]

@tsujan
The problem is gone after upgrading the rendering backend to OpenGL 3.1. I've only experienced this bug on OpenGL 2.0

[kupiqu]

The problem is gone after upgrading the rendering backend to OpenGL 3.1. I've only experienced this bug on OpenGL 2.0

Not in my case I suffer it in both. Try kwin --replace and check it again.

EDIT: Only workaround for me is using 'uxa', no other workaround has fixed the issue for me.

[tsujan]

The problem is gone after upgrading the rendering backend to OpenGL 3.1

Apparently, different systems need different settings. I'm happy with modesetting and OpenGL 3.1 when it comes to KWin. But when I used Compiz-reloaded (on LXQt), I needed the Intel driver and DRI2, maybe because Compiz-reloaded's code was old.

[ripefig]

@kupiqu @tsujan. Yeah, I lies OpenGL 3 causes the same problem, just less frequently.

The artifact is probably caused by the transparency feature (which I have turned off). The little artifacts are actually transparent and blurred. The whole problem seems to go away if blur effect is disabled or if your switch to regular breeze, which doesn't support transparency.

[ripefig]

@tsujan maybe consider making a version without transparency? that's what causing the bug.

[tsujan]

that's what causing the bug.

Translucency can't cause any bug.

[ripefig]

hmm, but this isn't observed in the breeze decoration. the artifacts are in fact translucent. there is also a little artifact in the corner..

breeze enhanced:

vs

breeze:

[ripefig]

that's with openGL 2/3

[trmdi]

Breeze does have this bug for some people. See the link to KDE Bug Tracker above.

[ripefig]

I have tried it with opengl 2/3, multiple times. never encountered it.

[trmdi]

I have tried it with opengl 2/3, multiple times. never encountered it.

This bug relates a lot to the video driver. But I don't think translucency is the root cause. If it was the root cause, everyone would get the bug. That's not true.

[tsujan]

@ripefig Please read the info gathered on this page, especially #10 (comment) . Saying or explaining the same thing over and over again wouldn't be useful.

As for bugs, their causes are some bad codes that have created them. Telling that translucency is the "cause" doesn't make sense.

[kupiqu]

I guess @ripefig just means it as a workaround until the real root cause is identified and fixed

[kupiqu]

I guess @ripefig just means it as a workaround until the real root cause is identified and fixed

I, for one, didn't experience the issue with vanilla breeze either

[tsujan]

Anyone can disable translucency in the Opacity setting. I won't remove that setting -- a title-bar without translucency is not an option for me.

[kupiqu]

Sure. I don't think anybody asked to remove the feature.

The setting seems not to be enough, which means that either it is not applied all around the code, or that translucency is in fact not triggering the issue, and sth else is doing it.

[tsujan]

@kupiqu After reading your last comment, I found and fixed an issue that was totally unrelated to this. I guess it was an example of what psychologists call "free association" ;)

[tsujan]

Today, I started my old Asus laptop (with broken screen - I use it with an external monitor only for testing Qt apps under gnome-shell) after 3 months to upgrade Manjaro on it and saw the artifacts reported here. Strange! The same programs (except for gnome) and the same driver (modesetting) with two different Intel cards but I've never seen these artifacts on my main laptop (Lenovo). Actually, the artifacts are hard to reproduce on the Asus but, somtimes, I can see them when maximizing windows.

I think the bug is in KWin. KDE had also different behaviors on these two computers a year ago but in the opposite direction: it worked well on the old laptop and bad on the new one. Now, it works like a charm on Lenovo but has this problem on the older Asus!

[trmdi]

the same driver (modesetting) with two different Intel cards

What will happen if you try an older version of the driver ?

[tsujan]

What will happen if you try an older version of the driver ?

Since I start that crappy laptop once in a few months, it isn't worth the effort... I should email it to KDE devs ;)

[trmdi]

Another artifact when I turn on Kwin's wobbly effect.
The line between the title bar and the window will appear when I move the window.

[tsujan]

@trmdi That artifact is VERY old and is visible with all kinds of titlebars. KDE devs never fixed it. Because of it and because the blur effect is disabled while moving, I never use the wobbly effect.

Compiz-reloaded also has this problem with all Emerald engines except for the pixmap engine.

[trmdi]

I would try reporting this bug again, it is a Kwin bug, isn't it? Is it very easy for everyone to reproduce the bug?

[tsujan]

it is a Kwin bug, isn't it?

Definitely.

Is it very easy for everyone to reproduce the bug?

It should be. I've seen it with various computers (mine and others').

Please note that it isn't limited to the wobbly effect or translucent windows. You could see it also when you show the desktop cube. In this screenshot, the cube is shown and rotated a little:

[tsujan]

I pressed the "reopen" button inadvertently, instead of file attachment button... Closed it again

[trmdi]

Kwin devs have looked at my report. You could go there and say something if you want: https://bugs.kde.org/show_bug.cgi?id=402595

[tsujan]

Oh, they made it a duplicate of https://bugs.kde.org/show_bug.cgi?id=257566 ; I had no idea that it was reported in 2011!! You know what that means ;)