Polybar tray in i3wm flickering

[Nawot]

Maybe you needed

OS: Manjaro 21.2.1 Qonos
Xgifwallpaper V: 0.3.1
Polybar V: 3.5.7
Picom V: vgit-c4107

What's happened

Hi all!
When xgifwallpaper working the tray of polybar beginning flickering.
If I kill xgifwallpaper that flicker will stop.
Once icons flickers with more intensity, other with less.

This look like this:

[calculon102]

Thank you for your report!

I can confirm this. Reproducible, even without running a compositor, like Picom.

At this first moment, I would suspect the issue in the tray-handling of Polybar. It listens on property-changes for pseudo-transparency, which are updated by xgifwallpaper every frame.

See https://github.com/polybar/polybar/blob/ab915fb724546e7abfcb35cbaf863ce2bca613ec/src/x11/tray_manager.cpp#L1019.

Still strange, that the tray-elements flicker at different intervals.

I leave this issue unclassified, until I have a better understanding of the cause.

[Nawot]

Oh, sorry, I overlooked that some icons sometimes disappear (just not visible, it's clickable) for a long time ~(40s-2m).
Maybe this info help to solve this problem

[Nawot]

I dug into the Polybar code and commented out random code pies. And I discovered that something happening in the refresh_window function. Something wrong when tray clearing.
If I comment out this line that flickering will stop

[calculon102]

Thank you, @Nawot!

Honestly, I don't know what to do about this within xgifwallpaper - at this moment. As far as I understand, every software component behaves correctly:

• xgifwallpaper updates atoms with reference of the background pixmap of the root window for composited windows
• polybar listens to atom changes, redraws itself
• polybar informs the tray-clients to redraw their complete content within the system-tray

This is all as designed... :) But surely leads to lots and lots of events and redraws of several clients within a second. Which (in my current opinion) leads to the effect. The flicker rate of the icons depending on the implementation of the eventual tray-client.

The only thing I could now think of, is to optimize polybar in a way, that a it only redraws the tray window and its client, only when it has a transparent background. That could soften the issue and fix it for you, when using a fully opaque bar-background.

I made a pull-request here: polybar/polybar#2604

You may try the fix youself: https://github.com/calculon102/polybar

I leave this issue open for now, maybe the polybar response gives alternative solutions or ideas.

[Nawot]

Hey! I wanted close this issues, but first I wanted test polybar with you solution. Since I didn't close, means something be wrong.
So, now I builded and installed new version the polybar from the source and flickering there is anyway. I don't know why. I thought that maybe this because my a old laptop is right the veeery old and can't normal rendering. But do you remember that I commented some line and flicker stopped? I don't know why you solution not working for me

[calculon102]

Hey @Nawot, the line you uncommented was a great hint. As a solution it was to broad, would have introduced regressions into polybar.

With the current solution, now pulled into polybar, the flicker should stop, if your bar has no transparency. If there is any, there is still flicker "as designed" - as there is still no solution to that. Honestly I don"t know, if I am able to solve this, at the moment.

For a test, try some solid color like #000000 as background for your bar.

[Nawot]

Alright. I just again will comment the there line and build the polybar while we would find solution. Anyway I not see other errors without this line

[Nawot]

Oh yes, if bg color set's to #00000 flicker stopping

[calculon102]

@Nawot that are great news! As long as you set background-color without transparency, it will not flicker. For example, only using six-digit RGB-hex-values, like #000000.

There is not much more to do here, I guess. For the line you commented in polybar: to reproduce the regression, try changing the wallpaper multiple times while using a compositor and polybar with transparent background. The background of the tray-icons won't be updated, then.