详细说明了VC中双缓冲绘图的方法，可以提高图形生成质量（当然不是我写的，但对我最近写的一个程序帮助很大，不会侵权吧）-detailed descr iption of VC-buffer mapping method can improve the quality of graphics generation (of course I did not write, but I recently wrote a procedure for the great help, it will not be infringement)