C#画笔Pen保存和恢复图形对象的设置方法

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Drawing2D;
namespace WindowsApplication2
{
  public partial class Form11 : Form
  {
    public Form11()
    {
      InitializeComponent();
    }
    private void button1_Click(object sender, EventArgs e)
    {
      LinearGradientBrush brush = new LinearGradientBrush(this.ClientRectangle, Color.Empty, Color.Empty, 100);
      ColorBlend blend = new ColorBlend();
      blend.Colors = new Color[] { Color.Red, Color.Green, Color.Blue };
      blend.Positions = new float[] { 0, .5f, 1 };
      brush.InterpolationColors = blend;
      Pen pen5 = new Pen(brush);
      Graphics g5 = this.CreateGraphics();
      Point[] p = new Point[] { new Point(0, 0), new Point(100, 100), new Point(50, 100), new Point(200, 100) };
      GraphicsState old = g5.Save();
      g5.SmoothingMode = SmoothingMode.AntiAlias;
      g5.Restore(old);
      g5.DrawCurve(pen5,p);
    }
  }
}