1 import Qt 4.7

     2 Rectangle {

     3     id: whiteRect

     4     width: 200 

     5     height: 200

     6     color: "white"

     7     Rectangle {

     8         id: blackRect

     9         objectName: "blackrect"

    10         color: "black"

    11         y: 50

    12         x: 50

    13         width: 100

    14         height: 100

    15         opacity: (whiteRect.width-blackRect.x+whiteRect.height-blackRect.y-199)/200

    16         Text { text: blackRect.opacity}

    17         MouseArea {

    18             objectName: "mouseregion"

    19             anchors.fill: parent

    20             drag.target: blackRect

    21             drag.axis: Drag.XandYAxis

    22             drag.minimumX: 0

    23             drag.maximumX: whiteRect.width-blackRect.width

    24             drag.minimumY: 0

    25             drag.maximumY: whiteRect.height-blackRect.height

    26          }

    27      }

    28  }