以CDC类的成员函数为基础，完成了一个基本几何图形绘制和效果填充的类CShape.实现的具体图形绘制有三种：1.几何轮廓绘制。2.单色几何图形的填充。3.颜色渐变填充。-To CDC class member functions, based on the completion of a basic geometric shapes drawn and effectiveness of the class filled CShape. To achieve a specific graphics