/// <summary>
        /// Starts this handler
        /// </summary>
        /// <param name="c">controller class</param>
        /// <param name="sensor">kinect sensor</param>
        public override void Start(Controller c, KinectSensor sensor)
        {
            controller = c;
            provider   = new PencilProvider(controller);
            provider.changeCursorToHand();
            if (sensor != null)
            {
                //load reader and register frame arrived delegate (listener)
                reader = sensor.BodyFrameSource.OpenReader();
                reader.FrameArrived += Reader_FrameArrived;

                coordinateMapper = sensor.CoordinateMapper;

                drawer            = controller.Ui.CanvasDrawer;
                drawer.controller = this.controller;
                drawer.provider   = this.provider;
            }
        }
        /// <summary>
        /// Starts this handler
        /// </summary>
        /// <param name="c">controller class</param>
        /// <param name="sensor">kinect sensor</param>
        public override void Start(Controller c, KinectSensor sensor)
        {
            controller = c;
            provider = new PencilProvider(controller);
            provider.changeCursorToHand();
            if (sensor != null)
            {
                //load reader and register frame arrived delegate (listener)
                reader = sensor.BodyFrameSource.OpenReader();
                reader.FrameArrived += Reader_FrameArrived;

                coordinateMapper = sensor.CoordinateMapper;

                drawer = controller.Ui.CanvasDrawer;
                drawer.controller = this.controller;
                drawer.provider = this.provider;

            }
        }