Hidden BusyIndicator still running in the background, How stop it completely (Qt 6.5)

majorRonk

        BusyIndicator {
           id: busyIndicator

           width: 120
           height: 120

           anchors.horizontalCenter: rootImage.horizontalCenter
           anchors.top: rootImage.top
           anchors.topMargin: 70

           visible: root.visible
        }

I try to set visible and/or running of the BusyIndicator to false but somehow its still running in the background and using a lot of cpu although its hidden.

Problem disappears when i manually minimize and maximize the app window.

I found an old thread and a bugfix with similar problem. But the customized BusyIndicator didnt fix the problem for me.
https://codereview.qt-project.org/c/qt/qtdeclarative/+/594118
https://forum.qt.io/topic/122897/what-causes-qsgrenderthread-to-have-constant-cpu-usage-on-a-static-scene

Is there any solution for Qt 6.5?

majorRonk

Other question:
Is it possible to access the animator property inside of the BusyIndicator and f.e. stop it ? (i guess its a RotationAnimator)

J.Hilk

BusyIndicator should have a "running" property. Set that to false

https://doc.qt.io/qt-6/qml-qtquick-controls-busyindicator.html#running-prop

Ronel_qtmaster

@majorRonk it still runs because BusyIndicator is running by default.
so just use
running: false
visible: false

majorRonk

As i said, setting running or visible to false does not solve the problem.

I have a QQuickItem (repeating drawing image of a vnc client) which starts after the animation ends.
I tested animators like RotationAnimator and ScaleAnimator.
Both continue to slow down my application,
even after i set running to false and the parent item's visibility is set to false.

Somehow its gone, when i minimize and maximize the mainwindow once.
I don't know why.
I'm working on Ubuntu 22.04, Qt 6.5.4

I had good experiences with replacing animations with FrameAnimation, but its hard to implement the same behaviour as in BusyIndicator.

J.Hilk

I somehow doubt that, setting running to false should stop the animation no matter what.

However if you really need a workaround, pack the BusyIndicator in a Loader and deactivate the loader. That will definitely destroy the object instance. If you still have issues after that, the problem is somewhere else in your code

majorRonk

@J.Hilk
I dynamically create and destroy Busyindicator with Loader by setting sourceComponent to undefined and this does not fix it...

Here some output for qt.scenegraph:

qt.scenegraph.general - debug - threaded render loop
qt.scenegraph.general - debug - Using sg animation driver
qt.scenegraph.general - debug - Animation Driver: using vsync: 16.67 ms
qt.scenegraph.general - debug - Using sg animation driver
qt.scenegraph.general - debug - Animation Driver: using vsync: 16.67 ms
qt.scenegraph.general - debug - Creating QRhi with backend OpenGL for window 0x61b18376bca0 (wflags 0x1)
qt.scenegraph.general - debug - Created QRhi 0x72b70c0049d0 for window 0x61b18376bca0
qt.scenegraph.general - debug - MSAA sample count for the swapchain is 1. Alpha channel requested = no.
qt.scenegraph.general - debug - rhi texture atlas dimensions: 1024x1024
qt.scenegraph.general - debug - animation driver switched to timer mode
qt.scenegraph.general - debug - Using sg animation driver
qt.scenegraph.general - debug - animation driver switched to vsync mode

I don't know if the animation driver timer/vsync mode switch has something to do with it?

majorRonk

This post is deleted!

majorRonk

I think a found what caused the slow performance.
In the same window i'm drawing a FrameAnimation
which is continously moving rectangle from left to right.
Actually its not a big computation.

Its strange, because i have already replaced a slower SequentialAnimation with this FrameAnimation. Which improves the performance.
Now i found out it still affects my application together with this BusyIndicator.

Still don't know why its only starting to work again after i minimize and maximize the window....

edit:

After i disable vsync with qputenv("QSG_NO_VSYNC", "0") it works again.