using System;
using System.Windows;
using System.Windows.Media;

public class MyDrawingVisual : DrawingVisual
{
    public void DrawEllipseWithHole()
    {
        using (DrawingContext drawingContext = RenderOpen())
        {
            // 創(chuàng)建外部大圓的EllipseGeometry
            EllipseGeometry outerEllipse = new EllipseGeometry(new Point(150, 150), 200, 200);

            // 創(chuàng)建內(nèi)部小圓的EllipseGeometry
            EllipseGeometry innerEllipse = new EllipseGeometry(new Point(150, 150), 100, 100);

            // 創(chuàng)建一個(gè)GeometryGroup，并將外部大圓和內(nèi)部小圓添加到其中
            GeometryGroup geometryGroup = new GeometryGroup();
            geometryGroup.FillRule = FillRule.EvenOdd; // 設(shè)置FillRule為EvenOdd以處理排除區(qū)域
            geometryGroup.Children.Add(outerEllipse);
            geometryGroup.Children.Add(innerEllipse);

            // 使用Geometry.Combine方法將內(nèi)部小圓的Geometry設(shè)置為Exclude模式，從而在最終的Geometry中去除中心的圓形區(qū)域
            geometryGroup = new GeometryGroup();
            geometryGroup.FillRule = FillRule.EvenOdd; // 設(shè)置FillRule為EvenOdd以處理排除區(qū)域
            geometryGroup.Children.Add(outerEllipse);
            geometryGroup.Children.Add(innerEllipse);

            geometryGroup = Geometry.Combine(geometryGroup, innerEllipse, GeometryCombineMode.Exclude, null);

            // 使用GeometryGroup繪制圓環(huán)
            drawingContext.DrawGeometry(Brushes.Blue, null, geometryGroup);
        }
    }
}

public class MainWindow : Window
{
    public MainWindow()
    {
        // 創(chuàng)建一個(gè)畫布
        DrawingVisual drawingVisual = new MyDrawingVisual();

        // 創(chuàng)建主窗口內(nèi)容
        ((MyDrawingVisual)drawingVisual).DrawEllipseWithHole();

        // 創(chuàng)建一個(gè)Image對(duì)象，用于顯示繪制的圖像
        Image imageControl = new Image();

        // 使用DrawingVisual對(duì)象創(chuàng)建一個(gè)DrawingImage
        DrawingImage drawingImage = new DrawingImage(drawingVisual.Drawing);

        // 將DrawingImage設(shè)置為Image控件的源
        imageControl.Source = drawingImage;

        // 將Image添加到主窗口中
        Content = imageControl;
    }
}

// 在這里調(diào)用主窗口
public class Program
{
    [STAThread]
    public static void Main(string[] args)
    {
        MainWindow mainWindow = new MainWindow();
        mainWindow.ShowDialog();
    }
}