纯MFC做的放大镜小例子，VC6,VS2010可以编译运行，支持自定义，支持当前鼠标位置放大，和当前放大窗口位置放大，圆形窗口，双缓冲绘图，有悬浮透明提示窗口，改变了传统的放大镜的实现　　按ESC或双击放大镜可退出程序-The the pure MFC do the magnifying glass small example, VC6, VS2010 can compile and run support custom support current mouse position zoom zoom zoom window position and the current round window, double-buffered graphics, suspended transparent prompt window, change the traditional magnifying glass press ESC or double-click the magnifying glass to exit the program