mfc 实现绘图功能的程序，基于单文档，能够实现线型选择，可以画矩形，椭圆，等等，还可以改变字体的大小。-MFC realize drawing function of the program, based on single document, will be able to realize the linear to choose, can draw rectangular, ellipse,, and so on, can also change the font size.