BSplineCurve2D BSplineCurve2D BSplineCurve2D copy getDegree getKnots getLength getMultiplicities getPeriodic getPoles getRational isClosed mDegree mKnots mMultiplicities mPeriodic mPoles mRational setDegree setKnots setMultiplicities setPeriodic setPoles setRational ~BSplineCurve2D

isClosed() bool isClosed ( ) virtual 判断是否闭合 true代表闭合，false代表不闭合 实现了 Curve2D. 被 NURBSCurve2D 重载.