用C#编写的一个用于数学二维函数作图的控件，支持直角坐标系及极坐标系，并能够将所作图形保存为图片。提供控件源代码以及测试程序。-A C# control for 2D mathematical functions plotting, support for Cartesian and polar coordinates, and the graphic can be saved as a picture. Provides source code and testing program.