【转】C# GDI+ 图像的双缓存技术

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 DoubleBuffer
{
    public partial class Form1 : Form
    {
        bool flag = true;
        Brush brush;
        public Form1()
        {
            InitializeComponent();
        }

        private void timerTest_Tick(object sender, EventArgs e)
        {
            if (rbYes.Checked)//默认
            {
                BasicDraw();
            }
            if(rbUser.Checked)//自己实现双缓冲原理
                UseMyImage();
            if (rbManual.Checked)//手动管理双缓冲
            {
                UseDoubleBuffer();
            }
            
         }
        private void BasicDraw()
        {
            DateTime t1 = DateTime.Now;
            Graphics g = this.CreateGraphics();
            Draw(g);
            DateTime t2 = DateTime.Now;
            TimeSpan sp = t2 - t1;
            float per = 1000 / sp.Milliseconds;
            lbSpeed.Text = "速度：" + per.ToString() + "帧/秒";
        }
        private void UseMyImage()
        {
            DateTime t1 = DateTime.Now;
            Bitmap bmp = new Bitmap(600, 600);
            Graphics g = Graphics.FromImage(bmp);
            Draw(g);
            this.CreateGraphics().DrawImage(bmp, 0, 0);
            DateTime t2 = DateTime.Now;
            TimeSpan sp = t2 - t1;
            float per = 1000 / sp.Milliseconds;
            lbSpeed.Text = "速度：" + per.ToString() + "帧/秒";
        }
        private void UseDoubleBuffer()
        {
            BufferedGraphicsContext currentContext = BufferedGraphicsManager.Current;
            BufferedGraphics myBuffer = currentContext.Allocate(this.CreateGraphics(), this.DisplayRectangle);
            DateTime t1 = DateTime.Now;
            Graphics g = myBuffer.Graphics;
            g.Clear(Button.DefaultBackColor);
            Draw(g);
            myBuffer.Render();
            DateTime t2 = DateTime.Now;
            TimeSpan sp = t2 - t1;
            float per = 1000 / sp.Milliseconds;
            lbSpeed.Text = "速度：" + per.ToString() + "帧/秒";
            myBuffer.Dispose(); 

        }
        private void Draw(Graphics g)
        {
            if (flag)
            {
                brush = new LinearGradientBrush(new PointF(0.0f, 0.0f),
                    new PointF(700.0f, 300.0f), Color.Red, Color.Blue);
                flag = false;
            }
            else
            {
                brush = new LinearGradientBrush(new PointF(0.0f, 0.0f),
                    new PointF(700.0f, 300.0f), Color.Blue, Color.Red);
                flag = true;
            }
            for (int j = 0; j < 60; j++)
            {
                for (int i = 0; i < 60; i++)
                {
                    g.FillEllipse(brush, i * 10, j * 10, 10, 10);
                }
            }
        }

        private void btnStart_Click(object sender, EventArgs e)
        {
            timerTest.Enabled = true;
        }

        private void btnStop_Click(object sender, EventArgs e)
        {
            timerTest.Enabled = false;
        }
    }
}