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[occt.git] / src / Law / Law_BSplineKnotSplitting.hxx

// Created on: 1997-01-17
// Created by: Philippe MANGIN
// Copyright (c) 1997-1999 Matra Datavision
// Copyright (c) 1999-2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef _Law_BSplineKnotSplitting_HeaderFile
#define _Law_BSplineKnotSplitting_HeaderFile

#include <Standard.hxx>
#include <Standard_DefineAlloc.hxx>
#include <Standard_Handle.hxx>

#include <TColStd_HArray1OfInteger.hxx>
#include <Standard_Integer.hxx>
#include <TColStd_Array1OfInteger.hxx>
class Standard_DimensionError;
class Standard_RangeError;
class Law_BSpline;



//! For a B-spline curve the discontinuities are localised at the
//! knot values and between two knots values the B-spline is
//! infinitely continuously differentiable.
//! At a knot of range index the continuity is equal to :
//! Degree - Mult (Index)   where  Degree is the degree of the
//! basis B-spline functions and Mult the multiplicity of the knot
//! of range Index.
//! If for your computation you need to have B-spline curves with a
//! minima of continuity it can be interesting to know between which
//! knot values, a B-spline curve arc, has a continuity of given order.
//! This algorithm computes the indexes of the knots where you should
//! split the curve, to obtain arcs with a constant continuity given
//! at the construction time. The splitting values are in the range
//! [FirstUKnotValue, LastUKnotValue] (See class B-spline curve from
//! package Geom).
//! If you just want to compute the local derivatives on the curve you
//! don't need to create the B-spline curve arcs, you can use the
//! functions LocalD1, LocalD2, LocalD3, LocalDN of the class
//! BSplineCurve.
class Law_BSplineKnotSplitting 
{
public:

  DEFINE_STANDARD_ALLOC

  

  //! Locates the knot values which correspond to the segmentation of
  //! the curve into arcs with a continuity equal to ContinuityRange.
  //!
  //! Raised if ContinuityRange is not greater or equal zero.
  Standard_EXPORT Law_BSplineKnotSplitting(const Handle(Law_BSpline)& BasisLaw, const Standard_Integer ContinuityRange);
  

  //! Returns the number of knots corresponding to the splitting.
  Standard_EXPORT Standard_Integer NbSplits() const;
  

  //! Returns the indexes of the BSpline curve knots corresponding to
  //! the splitting.
  //!
  //! Raised if the length of SplitValues is not equal to NbSPlit.
  Standard_EXPORT void Splitting (TColStd_Array1OfInteger& SplitValues) const;
  

  //! Returns the index of the knot corresponding to the splitting
  //! of range Index.
  //!
  //! Raised if Index < 1 or Index > NbSplits
  Standard_EXPORT Standard_Integer SplitValue (const Standard_Integer Index) const;




protected:





private:



  Handle(TColStd_HArray1OfInteger) splitIndexes;


};







#endif // _Law_BSplineKnotSplitting_HeaderFile