双缓冲原理以及双缓冲原理的实例

何谓“双缓冲”？它的基本原理就是：

先在内存中开辟一块虚拟画布，然后将所有需要画的图形先画在这块“虚拟画布”上，最后在一次性将整块画布画到真正的窗体上。

因为所有的单个图形的绘制都不是真正的调用显示系统来“画”，所以不会占用显示系统的开销，极大的提高的绘图效率。

实例1：

        #region 正常绘图
        /// <summary>
        /// 正常绘图
        /// </summary>
        private void NormalDraw()
        {
            DateTime t1 = DateTime.Now;
            Graphics g = this.CreateGraphics();
            Brush brush = null;

            bool flag = true;
            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);
                }
            }
            DateTime t2 = DateTime.Now;
            TimeSpan sp = t2 - t1;
            float per = 1000 / (sp.Milliseconds == 0 ? 1 : sp.Milliseconds);
            this.label1.Text = "速度：" + per.ToString() + "帧/秒";
        }
        #endregion

实例2：

        #region 启用双缓冲的绘图
        /// <summary>
        /// 启用双缓冲的绘图
        /// </summary>
        private void EnableDoubleBuffer()
        {
            DateTime t1 = DateTime.Now;

            Bitmap bmp = new Bitmap(6000, 6000);    //在内存中建立一块画布
            Graphics g = Graphics.FromImage(bmp);   //获取这块内存画布的Graphics引用：
            Brush brush = null;

            bool flag = true;
            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 < 600; j++)
            {
                for (int i = 0; i < 600; i++)
                {
                    //在这块内存画布上绘图
                    g.FillEllipse(brush, i * 10, j * 10, 10, 10);
                }
            }

            //将内存画布画到窗口中
            this.CreateGraphics().DrawImage(bmp, 0, 0);

            DateTime t2 = DateTime.Now;
            TimeSpan sp = t2 - t1;
            float per = 1000 / (sp.Milliseconds == 0 ? 1 : sp.Milliseconds);
            this.label1.Text = "速度：" + per.ToString() + "帧/秒";
        }
        #endregion

以上虽然可以模拟双缓冲原理，但是会出现画图的时候内存占用过高，优化方案如下：

        /// <summary>
        /// 优化双缓冲绘图
        /// 内存占用很小
        /// </summary>
        private void DoubleBufferDrawOptimize()
        {
            DateTime t1 = DateTime.Now;

            //在内存中建立一块画布,使用using 语法及时释放资源，避免画图对象没有及时回收导致内存飙升
            using (Bitmap bmp = new Bitmap(6000, 6000))
            {
                //获取这块内存画布的Graphics引用,对画布也要及时回收资源，
                using (Graphics g = Graphics.FromImage(bmp))
                {
                    Brush brush = null;

                    bool flag = true;
                    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 < 600; j++)
                    {
                        for (int i = 0; i < 600; i++)
                        {
                            //在这块内存画布上绘图
                            g.FillEllipse(brush, i * 10, j * 10, 10, 10);
                        }
                    }
                    //将内存画布画到窗口中
                    this.CreateGraphics().DrawImage(bmp, 0, 0);
                }
            }

            DateTime t2 = DateTime.Now;
            TimeSpan sp = t2 - t1;
            float per = 1000 / (sp.Milliseconds == 0 ? 1 : sp.Milliseconds);
            this.label1.Text = "速度：" + per.ToString() + "帧/秒";
        }

此代码是从别的技术群下载的群文件看到的，具有借鉴意义。

实例代码：http://files.cnblogs.com/files/wgx0428/Winfrom%E5%8F%8C%E7%BC%93%E5%86%B2%E7%BB%98%E5%9B%BE.zip