MFC双缓冲实现闪烁的处理，先把要画的图画到内存位图，最后再一次性刷到屏幕-process of double cache

利用了双缓冲技术在MFC对话框上进行高性能绘图,有效还解决了闪烁问题，给出了设计思路和代码实现。-Using double buffering technology in the MFC dialog box for high-performance graphics, effective also solved the flicker problem, given the design ideas and code to achieve.