C#仿简单的CAD矢量绘图源码.重点是模仿了CAD的矢量绘图功能，实现了画直线，长方形，圆形、选择线条颜色，线条粗细、移动以及清除等操作，还可以保存。-C# imitate a simple CAD vector graphics source. Focus on imitation of the CAD vector graphics to achieve a draw line, rectangle, circle, select the line color, line thickness