Qml滑块样式，在滑块句柄前后分配不同的凹槽颜色

import QtQuick 2.0

Slider {
    id: slider
    width: 200
    height: 40
    from: 0
    to: 100
    value: 50

    style: SliderStyle {
        groove: Rectangle {
            implicitWidth: 200
            implicitHeight: 10
            color: "lightgray"
        }

        handle: Rectangle {
            width: 20
            height: 20
            color: slider.value < 50 ? "green" : "red"
            radius: 10
        }
    }
}