图片重画

1.           /// <summary>
           /// 重写控件绘画事件, b缓冲图片,g,缓冲图片的Graphics
           /// </summary>
           /// <param name="e"></param>
           protected override void OnPaint(PaintEventArgs e)
           {
               g.Clear(this.BackColor);
               // 将要绘画的线画到缓冲图片上
               e.Graphics.DrawImage(b, new Point(0, 0)); // 重绘数据缓冲图像
           }
   
           /// <summary>
           /// 重写大小改变事件
           /// </summary>
           /// <param name="e"></param>
           protected override void OnSizeChanged(EventArgs e)
           {
               if (this.Width != 0 || this.Height != 0)
               {
                   b = new Bitmap(this.Width, this.Height);
                   g = Graphics.FromImage(btp);
                   base.OnSizeChanged(e);
               }
           }
   
           /// <summary>
           /// 重写绘画背景事件
           /// </summary>
           /// <param name="e"></param>
           protected override void OnPaintBackground(PaintEventArgs e)
           {
             // 一定要空实现
           }
   
2. 图片的背景、
3. 图片的全景