Canvas emits paint signal when invisible

import QtQuick 2.0

Canvas {
    id: canvas
    visible: false
    height: 200
    NumberAnimation on width {
        from: 200
        to: 300
        duration: 500
    }
    Timer {
        interval: 300
        running: true
        onTriggered: canvas.visible = true
    }
    onPaint: {
        print("Painting; Visible:" + canvas.visible)
    }
}