图形学的一个小型Vcad绘图程序，可以绘制直线，园，园弧，椭圆，可以直线剪裁，填充，还可以绘制Btz曲线-Graphics of a small Vcad drawing program, you can draw a straight line, park, park, arc, ellipse, straight line tailoring, filling, can also draw Btz curve