C#实现图形区域组合操作的方法

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace advanced_drawing
{
  public partial class Form17 : Form
  {
    public Form17()
    {
      InitializeComponent();
    }
    private void Form17_Paint(object sender, PaintEventArgs e)
    {
      Rectangle regionRect = new Rectangle(20, 20, 100, 100);
      e.Graphics.DrawRectangle(Pens.Black, regionRect);
      RectangleF unionRect = new RectangleF(90, 30, 100, 100);
      e.Graphics.DrawRectangle(Pens.Red, Rectangle.Round(unionRect));
      Region myRegion = new Region(regionRect);
      //myRegion.Union(unionRect);
      //myRegion.Intersect(unionRect);
      //myRegion.Exclude(unionRect);
      //myRegion.Complement(unionRect);
      myRegion.Xor(unionRect);
      SolidBrush myBrush = new SolidBrush(Color.Blue);
      e.Graphics.FillRegion(myBrush, myRegion);
    }
  }
}