QML Flickable Issues - qt

Question

I need a horizontal controller consisting of a background and moving thumb-stick. It requires the following behaviours:
Initially centred, the thumb-stick can drag to the left or right within the background bounds.
When the drag is released, the thumb-stick re-centres itself.
If a part of the background is touched, the thumb-stick jumps to the touch.
If the touch is released, the thumb-stick re-centres itself.
If a drag is made following the touch, the thumb-stick will drag from the touched position.
Problems:
On touch, the thumb-stick jumps to the TouchPoint as required. However if a drag immediately follows the touch, the thumb-stick jumps back to the position it was in before the touch, before initiating the drag.
If the thumb-stick is dragged to the right and released, it immediately jumps back to centre as required. If it is dragged to the left boundary, there is a delay before it jumps back to centre.
Running the below code illustrates the controller working and the problems:
import QtQuick 2.0
Item {
id: horizontalController
width: 300
height: 100
Rectangle {
id: controllerBackground
width: (parent.width / 3) * 2
height: parent.height
anchors.centerIn: parent
color: "white"
}
Flickable
{
id: controllerFlick
width: parent.width / 3 * 2
height: parent.height
anchors.centerIn: parent
contentX: width / 4
contentWidth: bounds.width
contentHeight: bounds.height
boundsBehavior: Flickable.StopAtBounds
onMovementEnded: {
contentX = width / 4
}
MultiPointTouchArea{
id: controllerTouchArea
enabled: true
anchors.fill: bounds
touchPoints: TouchPoint {id: controllerTouchPoint }
onPressed: {
controllerFlick.contentX = Math.min(Math.max(controllerBackground.width - controllerTouchPoint.x,0),controllerBackground.width / 2)
}
onReleased: {
controllerFlick.contentX = controllerFlick.width / 4
}
}
Item{
id: bounds
width: controllerFlick.width * 1.5
height: controllerFlick.height
Rectangle {
id: image
width: parent.width / 3
height: parent.height
anchors.centerIn: parent
color: "red"
}
}
}
}