5 property int xv:(knob.x-(width-knob.width)/2)*(200/(width-knob.width))
6 property int yv:(knob.y-(height-knob.height)/2)*(200/(height-knob.height))
12 x:parent.width/2-width/2
13 y:parent.width/2-height/2
17 anchors.centerIn:parent
29 drag.maximumX:parent.width-knob.width
30 drag.maximumY:parent.height-knob.height
32 onReleased:{knob.x=parent.width/2-knob.width/2;knob.y=parent.height/2-knob.height/2