Smooth repaint

[shkryab]

Hi!
I have elemens hierarchy like this:

RootItem.qml
@
import QtQuick 2.0

Flickable {
    id: flickable
    anchors.fill: parent
    contentHeight: content.height
    contentWidth: content.width

    visibleArea.onYPositionChanged:  item2.internalY = flickable.mapToItem( item2, 0, 20 ).y

    Item {
        id: content
        height:  800
        width: 300
        Column {
            anchors.fill: parent
            Level2 {
                id: item2
                anchors { left: parent.left; right: parent.right }
            }
        }
    }
}

@

Level2.qml
@
import QtQuick 2.0

Rectangle {
height: 800

property int internalY: 0

Level3 {
    anchors.fill: parent
    internalY: parent.internalY + 5
}

}
@

Level3.qml
@
import QtQuick 2.0

Item {
property int internalY: 0

Rectangle {
    id: internal
    height: 20
    width: 20
    anchors { right: parent.right }

    y: internalY + 5
}

}
@

Objective - positioning "internal" element relative to "flickable". In the example above all works fine. But in real project (with a large number of elements) on scrolling the "internal" element doesn't move smoothly. I think this is because the values ​​of properties are set through the event queue. If change all property ("internalY") to alias it is solve the problem. But moving all logic in root element - it's bad idea. Is there another solution?