Properties of PinchHandler's centroid are all empty

import QtQuick 2.12
import QtQuick.Window 2.2

Window {
    id: window
    objectName: "window"
    width: 600
    height: 800
    visible: true

    Rectangle {
        id: rect
        anchors.fill: parent
        color: "blue"

        PinchHandler {
            id: handler
            target: null//rect
            onScaleChanged: {
                print(scale, centroid.position, centroid.pressPosition, centroid.sceneGrabPosition, centroid.scenePosition, centroid.scenePressPosition)
            }
        }
    }
}