1 // Created on: 1993-03-24
3 // Copyright (c) 1993-1999 Matra Datavision
4 // Copyright (c) 1999-2014 OPEN CASCADE SAS
6 // This file is part of Open CASCADE Technology software library.
8 // This library is free software; you can redistribute it and/or modify it under
9 // the terms of the GNU Lesser General Public License version 2.1 as published
10 // by the Free Software Foundation, with special exception defined in the file
11 // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
12 // distribution for complete text of the license and disclaimer of any warranty.
14 // Alternatively, this file may be used under the terms of Open CASCADE
15 // commercial license or contractual agreement.
17 #ifndef _Geom2dConvert_BSplineCurveToBezierCurve_HeaderFile
18 #define _Geom2dConvert_BSplineCurveToBezierCurve_HeaderFile
20 #include <Standard.hxx>
21 #include <Standard_DefineAlloc.hxx>
22 #include <Standard_Handle.hxx>
24 #include <Standard_Real.hxx>
25 #include <Standard_Integer.hxx>
26 #include <TColGeom2d_Array1OfBezierCurve.hxx>
27 #include <TColStd_Array1OfReal.hxx>
28 class Geom2d_BSplineCurve;
29 class Standard_DimensionError;
30 class Standard_DomainError;
31 class Standard_OutOfRange;
32 class Geom2d_BezierCurve;
35 //! An algorithm to convert a BSpline curve into a series
36 //! of adjacent Bezier curves.
37 //! A BSplineCurveToBezierCurve object provides a framework for:
38 //! - defining the BSpline curve to be converted
39 //! - implementing the construction algorithm, and
40 //! - consulting the results.
42 //! Generating the Bezier points of B-spline curves and surfaces
43 //! (Wolfgang Bohm) CAD volume 13 number 6 november 1981
44 class Geom2dConvert_BSplineCurveToBezierCurve
51 //! Computes all the data needed to convert
52 //! - the BSpline curve BasisCurve, into a series of adjacent Bezier arcs.
53 //! The result consists of a series of BasisCurve arcs
54 //! limited by points corresponding to knot values of the curve.
55 //! Use the available interrogation functions to ascertain
56 //! the number of computed Bezier arcs, and then to
57 //! construct each individual Bezier curve (or all Bezier curves).
58 //! Note: ParametricTolerance is not used.
59 Standard_EXPORT Geom2dConvert_BSplineCurveToBezierCurve(const Handle(Geom2d_BSplineCurve)& BasisCurve);
61 //! Computes all the data needed to convert
62 //! the portion of the BSpline curve BasisCurve
63 //! limited by the two parameter values U1 and U2
64 //! for Example if there is a Knot Uk and
65 //! Uk < U < Uk + ParametricTolerance/2 the last curve
66 //! corresponds to the span [Uk-1, Uk] and not to [Uk, Uk+1]
67 //! The result consists of a series of BasisCurve arcs
68 //! limited by points corresponding to knot values of the curve.
69 //! Use the available interrogation functions to ascertain
70 //! the number of computed Bezier arcs, and then to
71 //! construct each individual Bezier curve (or all Bezier curves).
72 //! Note: ParametricTolerance is not used.
73 //! Raises DomainError if U1 or U2 are out of the parametric bounds of the basis
74 //! curve [FirstParameter, LastParameter]. The Tolerance criterion
75 //! is ParametricTolerance.
76 //! Raised if Abs (U2 - U1) <= ParametricTolerance.
77 Standard_EXPORT Geom2dConvert_BSplineCurveToBezierCurve(const Handle(Geom2d_BSplineCurve)& BasisCurve, const Standard_Real U1, const Standard_Real U2, const Standard_Real ParametricTolerance);
79 //! Constructs and returns the Bezier curve of index
80 //! Index to the table of adjacent Bezier arcs
81 //! computed by this algorithm.
82 //! This Bezier curve has the same orientation as the
83 //! BSpline curve analyzed in this framework.
85 //! Standard_OutOfRange if Index is less than 1 or
86 //! greater than the number of adjacent Bezier arcs
87 //! computed by this algorithm.
88 Standard_EXPORT Handle(Geom2d_BezierCurve) Arc (const Standard_Integer Index);
90 //! Constructs all the Bezier curves whose data is
91 //! computed by this algorithm and loads these curves
92 //! into the Curves table.
93 //! The Bezier curves have the same orientation as the
94 //! BSpline curve analyzed in this framework.
96 //! Standard_DimensionError if the Curves array was
97 //! not created with the following bounds:
99 //! - the number of adjacent Bezier arcs computed by
100 //! this algorithm (as given by the function NbArcs).
101 Standard_EXPORT void Arcs (TColGeom2d_Array1OfBezierCurve& Curves);
103 //! This methode returns the bspline's knots associated to
104 //! the converted arcs
105 //! Raises DimensionError if the length of Curves is not equal to
107 Standard_EXPORT void Knots (TColStd_Array1OfReal& TKnots) const;
110 //! Returns the number of BezierCurve arcs.
111 //! If at the creation time you have decomposed the basis curve
112 //! between the parametric values UFirst, ULast the number of
113 //! BezierCurve arcs depends on the number of knots included inside
114 //! the interval [UFirst, ULast].
115 //! If you have decomposed the whole basis B-spline curve the number
116 //! of BezierCurve arcs NbArcs is equal to the number of knots less
118 Standard_EXPORT Standard_Integer NbArcs() const;
133 Handle(Geom2d_BSplineCurve) myCurve;
144 #endif // _Geom2dConvert_BSplineCurveToBezierCurve_HeaderFile