Android QML canvas performance issue

[MartinD]

I use Qt 5.7.1 on Android.

My app contains some QML animations. They run smoothly until I use QML canvas in my app:

    Canvas {
        id: canvas
        onPaint: {
            var ctx = getContext("2d");
            ctx.reset();
        }
    }

    Timer {
            interval: 100; running: true; repeat: true
            onTriggered: canvas.requestPaint();
        }

The canvas paint method does nothing, only resets context.

This code causes my app not to run smoothly. Is there a bug in QML canvas or is there something bad in my code?

[jsulm]

@MartinD said in Android QML canvas performance issue:

canvas.requestPaint()

why do you need to call it?

[MartinD]

@jsulm There is additional code in my app - I need to redraw canvas when some property changes. But that's important. I don't think requesting canvas to paint and resetting it should block GUI thread.

[jsulm]

@MartinD said in Android QML canvas performance issue:

I need to redraw canvas when some property changes

Why don't you redraw when those properties change instead of doing it via timer?