用csharp及gdi+实现双缓存画图，解决画图时闪屏，刷新慢的问题，是了解双缓存画图的好东西-Gdi+ with csharp and achieve double-buffer drawing, solving the splash screen when drawing, slow refresh problem is to understand the double buffer drawing a good thing

双缓冲绘制图形，避免刷新时出现闪烁问题。-Double Buffer Drawing graphics