Question

椭圆弧在MxDrawCAD控件下为一个实体类：

class ARXDLL McDbEllipse : public  McDbCurve

即设置椭圆的开始弧度及结束弧度即可，如：

	double PI(3.1415);
	//在X = 200, Y = 200的位置，
	//圆心向X轴偏移长度为10的向量
	//圆心向Y轴偏移长度为10 * 0.2的向量
	//圆弧开始点顺时针转到X轴经过90°，
	//圆弧结束点顺时针转到X轴经过180°的弧
	{
		McDbEllipse * pEnt = new McDbEllipse(McGePoint3d(200, 200, 0),
			McGeVector3d(), McGeVector3d(10, 0, 0), 0.2, PI / 2, PI);
		SetEnt(256, _T("ByLayer"), pEnt);//颜色随层，线型随层
	}
	{
		McDbEllipse * pEnt = new McDbEllipse(McGePoint3d(300, 200, 0),
			McGeVector3d(), McGeVector3d(10, 0, 0), 0.2, PI / 2, PI);
		SetEnt(0, _T("ByBlock"), pEnt);//颜色随块，线型随块
	}
	{
		McDbEllipse * pEnt = new McDbEllipse(McGePoint3d(400, 200, 0),
			McGeVector3d(), McGeVector3d(10, 0, 0), 0.2, PI / 2, PI);
		SetEnt(2, _T("BORDER"), pEnt);//黄色，BORDER线型
	}