ArcofCircle2D ArcofCircle2D ArcofCircle2D calculateCircleCenter calculateStartandEndPoint copy getCenterPoint getDirection getEndAngle getEndPoint getExtrema getLength getMidPoint getRadius getStartAngle getStartPoint isClockWise isClosed isInArc mCenterPoint mClockWise mEndAngle mEndPoint mRadius mSecondPoint mStartAngle mStartPoint setCenterPoint setDirection setEndAngle setRadius setStartAngle

getStartAngle() double getStartAngle ( ) const 获取起始角度 获取二维圆弧起始角度