QSR state property changes accept only hardcoded values

SafePicture {
        id: car1
        objectName: "car1"
        //x: 0
        x: (0 -1 + 64) // calculations work here
        y: (0 -1 + 64)
        y: 0
        opacity: 1.0
        width: 64
        height: 64
        color: "#ff0000"
        source: "qrc:/iso-icons/iso_grs_7000_4_1358.dat"

        property int my_x1
        property int my_x2
        my_x1: 100
        my_x2: 200
        states: [
                State {
                    name: "A"
                    PropertyChanges {
                        target: car1
                        x: 100 // this is the only one that works
                        //x: my_x1 // does not work
                        //x: 100 + 100 // does not work
                        y: 0
                        opacity: 0.8
                        color: "#0000ff"
                    }
                },
                State {
                    name: "B"
                    PropertyChanges {
                        target: car1
                        //x: (0 -1 + 64*2)
                        x: my_x2 // so caput
                        //x:128
                        y: 128
                        opacity: 0.8
                        color: "#0000ff"
                    }
                }
        ]