1 // Copyright (c) 1995-1999 Matra Datavision
2 // Copyright (c) 1999-2014 OPEN CASCADE SAS
3 //
4 // This file is part of Open CASCADE Technology software library.
5 //
6 // This library is free software; you can redistribute it and/or modify it under
7 // the terms of the GNU Lesser General Public License version 2.1 as published
8 // by the Free Software Foundation, with special exception defined in the file
9 // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
10 // distribution for complete text of the license and disclaimer of any warranty.
11 //
12 // Alternatively, this file may be used under the terms of Open CASCADE
13 // commercial license or contractual agreement.
14
15 //JCV 16/10/91
16
17 #include <Convert_EllipseToBSplineCurve.hxx>
18 #include <gp.hxx>
19 #include <gp_Ax2d.hxx>
20 #include <gp_Dir2d.hxx>
21 #include <gp_Elips2d.hxx>
22 #include <gp_Trsf2d.hxx>
23 #include <Precision.hxx>
24 #include <Standard_DomainError.hxx>
25 #include <TColgp_Array1OfPnt2d.hxx>
26 #include <TColgp_HArray1OfPnt2d.hxx>
27 #include <TColStd_Array1OfReal.hxx>
28 #include <TColStd_HArray1OfInteger.hxx>
29 #include <TColStd_HArray1OfReal.hxx>
30
31 //Attention :
32 //To avoid use of persistent tables in the fields
33 //the tables are dimensioned to the maximum (TheNbKnots and TheNbPoles)
34 //that correspond to the full circle. For an arc of circle there is a
35 //need of less poles and nodes, that is why the fields
36 //nbKnots and nbPoles are present and updated in the
37 //constructor of an arc of B-spline circle to take into account
38 //the real number of poles and nodes.
39 // parameterization :
40 // Reference : Rational B-spline for Curve and Surface Representation
41 // Wayne Tiller CADG September 1983
42 // x(t) = (1 - t^2) / (1 + t^2)
43 // y(t) = 2 t / (1 + t^2)
44 // then t = Sqrt(2) u / ((Sqrt(2) - 2) u + 2)
45 // => u = 2 t / (Sqrt(2) + (2 - Sqrt(2)) t)
46 //=======================================================================
47 //function : Convert_EllipseToBSplineCurve
48 //purpose : this constructs a periodic Ellipse
49 //=======================================================================
Convert_EllipseToBSplineCurve(const gp_Elips2d & E,const Convert_ParameterisationType Parameterisation)50 Convert_EllipseToBSplineCurve::Convert_EllipseToBSplineCurve
51 (const gp_Elips2d& E, const Convert_ParameterisationType Parameterisation)
52 :Convert_ConicToBSplineCurve(0,0,0){
53
54 Standard_Integer ii ;
55
56 Standard_Real R,
57 r,
58 value ;
59 Handle(TColStd_HArray1OfReal) CosNumeratorPtr,
60 SinNumeratorPtr ;
61
62
63 R = E.MajorRadius();
64 r = E.MinorRadius();
65
66
67 if (Parameterisation != Convert_TgtThetaOver2 &&
68 Parameterisation != Convert_RationalC1) {
69 // If BuildCosAndSin cannot manage the periodicity
70 // => trim on 0,2*PI
71 isperiodic = Standard_False;
72 Convert_ConicToBSplineCurve::
73 BuildCosAndSin(Parameterisation,
74 0, 2*M_PI,
75 CosNumeratorPtr,
76 SinNumeratorPtr,
77 weights,
78 degree,
79 knots,
80 mults) ;
81 }
82 else {
83 isperiodic = Standard_True;
84 Convert_ConicToBSplineCurve::
85 BuildCosAndSin(Parameterisation,
86 CosNumeratorPtr,
87 SinNumeratorPtr,
88 weights,
89 degree,
90 knots,
91 mults);
92 }
93
94 nbPoles = CosNumeratorPtr->Length();
95 nbKnots = knots->Length();
96
97 poles =
98 new TColgp_HArray1OfPnt2d(1,nbPoles) ;
99
100
101 gp_Dir2d Ox = E.XAxis().Direction();
102 gp_Dir2d Oy = E.YAxis().Direction();
103 gp_Trsf2d Trsf;
104 Trsf.SetTransformation( E.XAxis(), gp::OX2d());
105 if ( Ox.X() * Oy.Y() - Ox.Y() * Oy.X() > 0.0e0) {
106 value = r ;
107 }
108 else {
109 value = -r ;
110 }
111
112 // Replace the bspline in the mark of the circle.
113 // and calculate the weight of the bspline.
114
115 for (ii = 1; ii <= nbPoles ; ii++) {
116 poles->ChangeArray1()(ii).SetCoord(1, R * CosNumeratorPtr->Value(ii)) ;
117 poles->ChangeArray1()(ii).SetCoord(2, value * SinNumeratorPtr->Value(ii)) ;
118 poles->ChangeArray1()(ii).Transform( Trsf);
119 }
120
121 }
122 //=======================================================================
123 //function : Convert_EllipseToBSplineCurve
124 //purpose : this constructs a non periodic Ellipse
125 //=======================================================================
126
Convert_EllipseToBSplineCurve(const gp_Elips2d & E,const Standard_Real UFirst,const Standard_Real ULast,const Convert_ParameterisationType Parameterisation)127 Convert_EllipseToBSplineCurve::Convert_EllipseToBSplineCurve
128 (const gp_Elips2d& E,
129 const Standard_Real UFirst,
130 const Standard_Real ULast,
131 const Convert_ParameterisationType Parameterisation)
132 :Convert_ConicToBSplineCurve(0,0,0)
133 {
134 #ifndef No_Exception
135 Standard_Real Tol = Precision::PConfusion();
136 Standard_Real delta = ULast - UFirst;
137 #endif
138 Standard_DomainError_Raise_if( (delta > (2*M_PI+Tol)) || (delta <= 0.0e0),
139 "Convert_EllipseToBSplineCurve");
140 Standard_Integer ii;
141 Standard_Real R, r, value;
142 Handle(TColStd_HArray1OfReal) CosNumeratorPtr, SinNumeratorPtr;
143
144 R = E.MajorRadius();
145 r = E.MinorRadius();
146
147 isperiodic = Standard_False;
148 Convert_ConicToBSplineCurve::BuildCosAndSin(Parameterisation,
149 UFirst,
150 ULast,
151 CosNumeratorPtr,
152 SinNumeratorPtr,
153 weights,
154 degree,
155 knots,
156 mults) ;
157
158 nbPoles = CosNumeratorPtr->Length();
159 nbKnots = knots->Length();
160
161 poles = new TColgp_HArray1OfPnt2d(1,nbPoles) ;
162
163 gp_Dir2d Ox = E.XAxis().Direction();
164 gp_Dir2d Oy = E.YAxis().Direction();
165 gp_Trsf2d Trsf;
166 Trsf.SetTransformation( E.XAxis(), gp::OX2d());
167 if ( Ox.X() * Oy.Y() - Ox.Y() * Oy.X() > 0.0e0) {
168 value = r ;
169 }
170 else {
171 value = -r ;
172 }
173
174 // Replace the bspline in the mark of the circle.
175 // and calculate the weight of the bspline.
176
177 for (ii = 1; ii <= nbPoles ; ii++) {
178 poles->ChangeArray1()(ii).SetCoord(1, R * CosNumeratorPtr->Value(ii)) ;
179 poles->ChangeArray1()(ii).SetCoord(2, value * SinNumeratorPtr->Value(ii)) ;
180 poles->ChangeArray1()(ii).Transform( Trsf);
181 }
182
183 }
184
185