练习使用GDI函数绘出基本几何元素，如点、线、矩形、圆、椭圆、多边形、圆弧等、并能够用颜色填充；练习使用GDI函数显示图像；-Practice using GDI functions to draw basic geometry elements such as points, lines, rectangles, circles, ellipses, polygons, arcs, etc., and can be filled with colors　practice using GDI functions to display images