silverlight 画图InkPresenter

 <UserControl x:Class="SilverlightTest.PolygonTest"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     xmlns:controls="clr-namespace:Custom.Controls;assembly=Custom.Controls"
     mc:Ignorable="d"
     d:DesignHeight="" d:DesignWidth="">

     <Canvas x:Name="LayoutRoot" Width="" Height="">
         <Canvas.Background>
             <ImageBrush ImageSource="/SilverlightTest;component/Images/map.png" Stretch="None" />
         </Canvas.Background>

         <Rectangle Margin="" Stroke="Black" Width="" Height="" />
         <InkPresenter x:Name="MyIP" Width="" Height="" Margin="" MouseLeftButtonDown="MyIP_MouseLeftButtonDown"
                       LostMouseCapture="MyIP_LostMouseCapture" MouseMove="MyIP_MouseMove" Background="Transparent" Opacity="">
         </InkPresenter>
         <!--<Polygon MouseEnter="OnMouseEnter" MouseLeave="OnMouseLeave" Fill="#FF000000" Opacity="0.5" Visibility="Visible" StrokeThickness="" Stroke="#FF222935"
                  Points="219,122 221,124 221,128 221,132 221,135 221,138 221,141 221,145 221,148 221,151 221,154
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         <!-- ,, -->
     </Canvas>
 </UserControl>

using System.Windows;
using System.Windows.Controls;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Shapes;

namespace SilverlightTest
{
    public partial class PolygonTest : UserControl
    {
        Stroke NewStroke;

        public PolygonTest()
        {
            InitializeComponent();
            SetBoundary();
        }

        private void OnMouseEnter(object sender, System.Windows.Input.MouseEventArgs e)
        {
            Polygon pl = sender as Polygon;
            if (pl == null) return;
            SetProperty(pl, , );
        }

        private void OnMouseLeave(object sender, System.Windows.Input.MouseEventArgs e)
        {
            Polygon pl = sender as Polygon;
            if (pl == null) return;
            SetProperty(pl, 0.5, );
        }

        private void SetProperty(Polygon pl, double opacity, double thickness)
        {
            pl.Opacity = opacity;
            pl.StrokeThickness = thickness;
        }

        private void SetBoundary()
        {
            RectangleGeometry MyRectangleGeometry = new RectangleGeometry();
            MyRectangleGeometry.Rect = new Rect(, , MyIP.ActualWidth, MyIP.ActualHeight);
            MyIP.Clip = MyRectangleGeometry;
        }

        private void MyIP_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
        {
            MyIP.CaptureMouse();
            StylusPointCollection MyStylusPointCollection = new StylusPointCollection();
            MyStylusPointCollection.Add(e.StylusDevice.GetStylusPoints(MyIP));
            NewStroke = new Stroke(MyStylusPointCollection);
            MyIP.Strokes.Add(NewStroke);
        }

        private void MyIP_LostMouseCapture(object sender, System.Windows.Input.MouseEventArgs e)
        {
            string str = string.Empty;
            int index = ;
            foreach (var item in NewStroke.StylusPoints)
            {
                if (index %  == )
                    str += item.X.ToString() + "," + item.Y.ToString() + " ";
                index++;
            }
            str = str.Trim();
            MessageBox.Show(str);
            NewStroke = null;
        }

        private void MyIP_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
        {
            if (NewStroke != null)
                NewStroke.StylusPoints.Add(e.StylusDevice.GetStylusPoints(MyIP));
        }
    }
}