RubberBand in qml

stereomatching

I want to crop the Image in qml, like this

"crop":http://www.flickr.com/photos/92283971@N04/9228168345/

The region surrounded by the rectangle is the region I want to crop
Do Qt provide any tools to make this job easier?

@
import QtQuick 2.1
import QtQuick.Controls 1.0
//import QtQuick.Layouts 1.0
//import QtQuick.Dialogs 1.0

Rectangle {
id: root
width: 1200
height: 600

Rectangle{
    anchors.fill: parent

    color: "black"

    Rectangle{
        id: rectDrag

        height: 100
        width: 100

        color: "transparent"
        border.width: 5
        border.color: "green"
        Drag.active: dragArea.drag.active
        radius: 10

        MouseArea {
            id: dragArea
            anchors.fill: parent

            drag.target: parent
        }            
    }
}

}
@

I can drag the rectangle and find out the coordinates of the rectangle
But there are two questions I don't know how to solve

1 : How could I adjust the size of rectDrag by pulling the corners of the rectDrag?
2 : After I select the region, I need to translate the coordinates(region) to the coordinates
of the original image, how could I translate the coordinates after scaling by the
fillMode--Image.PreserveAspectFit?

edit: found Qt offer a rubberband class in c++, maybe I could use it to implement the
rubberband?