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0001 // Created on: 1993-03-24 0002 // Created by: DUB 0003 // Copyright (c) 1993-1999 Matra Datavision 0004 // Copyright (c) 1999-2014 OPEN CASCADE SAS 0005 // 0006 // This file is part of Open CASCADE Technology software library. 0007 // 0008 // This library is free software; you can redistribute it and/or modify it under 0009 // the terms of the GNU Lesser General Public License version 2.1 as published 0010 // by the Free Software Foundation, with special exception defined in the file 0011 // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT 0012 // distribution for complete text of the license and disclaimer of any warranty. 0013 // 0014 // Alternatively, this file may be used under the terms of Open CASCADE 0015 // commercial license or contractual agreement. 0016 0017 #ifndef _Geom2dConvert_BSplineCurveToBezierCurve_HeaderFile 0018 #define _Geom2dConvert_BSplineCurveToBezierCurve_HeaderFile 0019 0020 #include <Standard.hxx> 0021 #include <Standard_DefineAlloc.hxx> 0022 #include <Standard_Handle.hxx> 0023 0024 #include <Standard_Integer.hxx> 0025 #include <TColGeom2d_Array1OfBezierCurve.hxx> 0026 #include <TColStd_Array1OfReal.hxx> 0027 class Geom2d_BSplineCurve; 0028 class Geom2d_BezierCurve; 0029 0030 //! An algorithm to convert a BSpline curve into a series 0031 //! of adjacent Bezier curves. 0032 //! A BSplineCurveToBezierCurve object provides a framework for: 0033 //! - defining the BSpline curve to be converted 0034 //! - implementing the construction algorithm, and 0035 //! - consulting the results. 0036 //! References : 0037 //! Generating the Bezier points of B-spline curves and surfaces 0038 //! (Wolfgang Bohm) CAD volume 13 number 6 november 1981 0039 class Geom2dConvert_BSplineCurveToBezierCurve 0040 { 0041 public: 0042 DEFINE_STANDARD_ALLOC 0043 0044 //! Computes all the data needed to convert 0045 //! - the BSpline curve BasisCurve, into a series of adjacent Bezier arcs. 0046 //! The result consists of a series of BasisCurve arcs 0047 //! limited by points corresponding to knot values of the curve. 0048 //! Use the available interrogation functions to ascertain 0049 //! the number of computed Bezier arcs, and then to 0050 //! construct each individual Bezier curve (or all Bezier curves). 0051 //! Note: ParametricTolerance is not used. 0052 Standard_EXPORT Geom2dConvert_BSplineCurveToBezierCurve( 0053 const Handle(Geom2d_BSplineCurve)& BasisCurve); 0054 0055 //! Computes all the data needed to convert 0056 //! the portion of the BSpline curve BasisCurve 0057 //! limited by the two parameter values U1 and U2 0058 //! for Example if there is a Knot Uk and 0059 //! Uk < U < Uk + ParametricTolerance/2 the last curve 0060 //! corresponds to the span [Uk-1, Uk] and not to [Uk, Uk+1] 0061 //! The result consists of a series of BasisCurve arcs 0062 //! limited by points corresponding to knot values of the curve. 0063 //! Use the available interrogation functions to ascertain 0064 //! the number of computed Bezier arcs, and then to 0065 //! construct each individual Bezier curve (or all Bezier curves). 0066 //! Note: ParametricTolerance is not used. 0067 //! Raises DomainError if U1 or U2 are out of the parametric bounds of the basis 0068 //! curve [FirstParameter, LastParameter]. The Tolerance criterion 0069 //! is ParametricTolerance. 0070 //! Raised if Abs (U2 - U1) <= ParametricTolerance. 0071 Standard_EXPORT Geom2dConvert_BSplineCurveToBezierCurve( 0072 const Handle(Geom2d_BSplineCurve)& BasisCurve, 0073 const Standard_Real U1, 0074 const Standard_Real U2, 0075 const Standard_Real ParametricTolerance); 0076 0077 //! Constructs and returns the Bezier curve of index 0078 //! Index to the table of adjacent Bezier arcs 0079 //! computed by this algorithm. 0080 //! This Bezier curve has the same orientation as the 0081 //! BSpline curve analyzed in this framework. 0082 //! Exceptions 0083 //! Standard_OutOfRange if Index is less than 1 or 0084 //! greater than the number of adjacent Bezier arcs 0085 //! computed by this algorithm. 0086 Standard_EXPORT Handle(Geom2d_BezierCurve) Arc(const Standard_Integer Index); 0087 0088 //! Constructs all the Bezier curves whose data is 0089 //! computed by this algorithm and loads these curves 0090 //! into the Curves table. 0091 //! The Bezier curves have the same orientation as the 0092 //! BSpline curve analyzed in this framework. 0093 //! Exceptions 0094 //! Standard_DimensionError if the Curves array was 0095 //! not created with the following bounds: 0096 //! - 1 , and 0097 //! - the number of adjacent Bezier arcs computed by 0098 //! this algorithm (as given by the function NbArcs). 0099 Standard_EXPORT void Arcs(TColGeom2d_Array1OfBezierCurve& Curves); 0100 0101 //! This methode returns the bspline's knots associated to 0102 //! the converted arcs 0103 //! Raises DimensionError if the length of Curves is not equal to 0104 //! NbArcs + 1 0105 Standard_EXPORT void Knots(TColStd_Array1OfReal& TKnots) const; 0106 0107 //! Returns the number of BezierCurve arcs. 0108 //! If at the creation time you have decomposed the basis curve 0109 //! between the parametric values UFirst, ULast the number of 0110 //! BezierCurve arcs depends on the number of knots included inside 0111 //! the interval [UFirst, ULast]. 0112 //! If you have decomposed the whole basis B-spline curve the number 0113 //! of BezierCurve arcs NbArcs is equal to the number of knots less 0114 //! one. 0115 Standard_EXPORT Standard_Integer NbArcs() const; 0116 0117 protected: 0118 private: 0119 Handle(Geom2d_BSplineCurve) myCurve; 0120 }; 0121 0122 #endif // _Geom2dConvert_BSplineCurveToBezierCurve_HeaderFile
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