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occt/src/Geom2dConvert/Geom2dConvert_BSplineCurveToBezierCurve.hxx

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// Created on: 1993-03-24
// Created by: DUB
// Copyright (c) 1993-1999 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 _Geom2dConvert_BSplineCurveToBezierCurve_HeaderFile
#define _Geom2dConvert_BSplineCurveToBezierCurve_HeaderFile
#include <Standard.hxx>
#include <Standard_DefineAlloc.hxx>
#include <Standard_Handle.hxx>
#include <Standard_Real.hxx>
#include <Standard_Integer.hxx>
#include <TColGeom2d_Array1OfBezierCurve.hxx>
#include <TColStd_Array1OfReal.hxx>
class Geom2d_BSplineCurve;
class Geom2d_BezierCurve;
//! An algorithm to convert a BSpline curve into a series
//! of adjacent Bezier curves.
//! A BSplineCurveToBezierCurve object provides a framework for:
//! - defining the BSpline curve to be converted
//! - implementing the construction algorithm, and
//! - consulting the results.
//! References :
//! Generating the Bezier points of B-spline curves and surfaces
//! (Wolfgang Bohm) CAD volume 13 number 6 november 1981
class Geom2dConvert_BSplineCurveToBezierCurve
{
public:
DEFINE_STANDARD_ALLOC
//! Computes all the data needed to convert
//! - the BSpline curve BasisCurve, into a series of adjacent Bezier arcs.
//! The result consists of a series of BasisCurve arcs
//! limited by points corresponding to knot values of the curve.
//! Use the available interrogation functions to ascertain
//! the number of computed Bezier arcs, and then to
//! construct each individual Bezier curve (or all Bezier curves).
//! Note: ParametricTolerance is not used.
Standard_EXPORT Geom2dConvert_BSplineCurveToBezierCurve(const Handle(Geom2d_BSplineCurve)& BasisCurve);
//! Computes all the data needed to convert
//! the portion of the BSpline curve BasisCurve
//! limited by the two parameter values U1 and U2
//! for Example if there is a Knot Uk and
//! Uk < U < Uk + ParametricTolerance/2 the last curve
//! corresponds to the span [Uk-1, Uk] and not to [Uk, Uk+1]
//! The result consists of a series of BasisCurve arcs
//! limited by points corresponding to knot values of the curve.
//! Use the available interrogation functions to ascertain
//! the number of computed Bezier arcs, and then to
//! construct each individual Bezier curve (or all Bezier curves).
//! Note: ParametricTolerance is not used.
//! Raises DomainError if U1 or U2 are out of the parametric bounds of the basis
//! curve [FirstParameter, LastParameter]. The Tolerance criterion
//! is ParametricTolerance.
//! Raised if Abs (U2 - U1) <= ParametricTolerance.
Standard_EXPORT Geom2dConvert_BSplineCurveToBezierCurve(const Handle(Geom2d_BSplineCurve)& BasisCurve, const Standard_Real U1, const Standard_Real U2, const Standard_Real ParametricTolerance);
//! Constructs and returns the Bezier curve of index
//! Index to the table of adjacent Bezier arcs
//! computed by this algorithm.
//! This Bezier curve has the same orientation as the
//! BSpline curve analyzed in this framework.
//! Exceptions
//! Standard_OutOfRange if Index is less than 1 or
//! greater than the number of adjacent Bezier arcs
//! computed by this algorithm.
Standard_EXPORT Handle(Geom2d_BezierCurve) Arc (const Standard_Integer Index);
//! Constructs all the Bezier curves whose data is
//! computed by this algorithm and loads these curves
//! into the Curves table.
//! The Bezier curves have the same orientation as the
//! BSpline curve analyzed in this framework.
//! Exceptions
//! Standard_DimensionError if the Curves array was
//! not created with the following bounds:
//! - 1 , and
//! - the number of adjacent Bezier arcs computed by
//! this algorithm (as given by the function NbArcs).
Standard_EXPORT void Arcs (TColGeom2d_Array1OfBezierCurve& Curves);
//! This methode returns the bspline's knots associated to
//! the converted arcs
//! Raises DimensionError if the length of Curves is not equal to
//! NbArcs + 1
Standard_EXPORT void Knots (TColStd_Array1OfReal& TKnots) const;
//! Returns the number of BezierCurve arcs.
//! If at the creation time you have decomposed the basis curve
//! between the parametric values UFirst, ULast the number of
//! BezierCurve arcs depends on the number of knots included inside
//! the interval [UFirst, ULast].
//! If you have decomposed the whole basis B-spline curve the number
//! of BezierCurve arcs NbArcs is equal to the number of knots less
//! one.
Standard_EXPORT Standard_Integer NbArcs() const;
protected:
private:
Handle(Geom2d_BSplineCurve) myCurve;
};
#endif // _Geom2dConvert_BSplineCurveToBezierCurve_HeaderFile