WPF HitTestResult

using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApp81
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        List<Visual> visualsList = new List<Visual>();
        public MainWindow()
        {
            InitializeComponent();
            Title = "Hosting DrawingVisuals";
            Width = 300;
            Height = 350;

            DrawingVisual bodyVisual = new DrawingVisual();
            DrawingVisual eyesVisual = new DrawingVisual();
            DrawingVisual mouthVisual = new DrawingVisual();

            using (DrawingContext dc = bodyVisual.RenderOpen())
            {
                dc.DrawGeometry(Brushes.Blue, null, Geometry.Parse(@"M 240,250 
                C 200, 375 200,250 175,200
                C 100, 400 100,250 100,200
                C 0,350 0,250 30,130
                C 75,0 100,0 150,0
                C 200,0 250,0 250,150 Z"));
            }

            using (DrawingContext dc = eyesVisual.RenderOpen())
            {
                dc.DrawEllipse(Brushes.Black, new Pen(Brushes.White, 10),
                    new Point(95, 95), 15, 15);
                dc.DrawEllipse(Brushes.Black, new Pen(Brushes.White, 10),
                    new Point(170, 105), 15, 15);
            }

            using (DrawingContext dc = mouthVisual.RenderOpen())
            {
                Pen p = new Pen(Brushes.Black, 10);
                p.StartLineCap = PenLineCap.Round;
                p.EndLineCap = PenLineCap.Round;
                dc.DrawLine(p, new Point(75, 160), new Point(175, 150));
            }

            visualsList.Add(bodyVisual);
            visualsList.Add(eyesVisual);
            visualsList.Add(mouthVisual);

            foreach (Visual vl in visualsList)
            {
                AddVisualChild(vl);
                AddLogicalChild(vl);
            }

        }


        protected override int VisualChildrenCount
        {
            get
            {
                return visualsList.Count;
            }
        }

        protected override Visual GetVisualChild(int index)
        {
            if (index < 0 || index >= visualsList.Count)
            {
                throw new ArgumentOutOfRangeException("index");
            }
            return visualsList[index];
        }

        protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)
        {
            base.OnMouseLeftButtonDown(e);

            Point location=e.GetPosition(this);

            HitTestResult result=VisualTreeHelper.HitTest(this, location);
            if(result.VisualHit.GetType()==typeof(DrawingVisual))
            {
                DrawingVisual dv=result.VisualHit as DrawingVisual;
                if(dv.Transform==null)
                {
                    dv.Transform = new RotateTransform();
                }
                (dv.Transform as RotateTransform).Angle++;
            }             
        }

        private HitTestResultBehavior HitTestCallback(HitTestResult result)
        {
            if(result.VisualHit.GetType()== typeof(HitTestResult))
            {
                DrawingVisual dv=result.VisualHit as DrawingVisual;
                if(dv.Transform==null)
                {
                    dv.Transform = new RotateTransform();
                }
                (dv.Transform as RotateTransform).Angle++;
            }
            return HitTestResultBehavior.Continue;
        }

        protected override void OnMouseRightButtonDown(MouseButtonEventArgs e)
        {
            base.OnMouseRightButtonDown(e);
            Point location = e.GetPosition(this);
            HitTestResult result = VisualTreeHelper.HitTest(this, location);
            if (result.VisualHit.GetType() == typeof(DrawingVisual))
            {
                DrawingVisual dv = result.VisualHit as DrawingVisual;
                if (dv.Transform == null)
                {
                    dv.Transform = new RotateTransform();
                }
                (dv.Transform as RotateTransform).Angle--;
            }
        }
    }
}