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1 | // Created on: 1993-03-10 |
2 | // Created by: JCV |
3 | // Copyright (c) 1993-1999 Matra Datavision |
4 | // Copyright (c) 1999-2014 OPEN CASCADE SAS |
5 | // |
6 | // This file is part of Open CASCADE Technology software library. |
7 | // |
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. |
13 | // |
14 | // Alternatively, this file may be used under the terms of Open CASCADE |
15 | // commercial license or contractual agreement. |
16 | |
17 | #ifndef _Geom_Curve_HeaderFile |
18 | #define _Geom_Curve_HeaderFile |
19 | |
20 | #include <Standard.hxx> |
21 | #include <Standard_Type.hxx> |
22 | |
23 | #include <Geom_Geometry.hxx> |
24 | #include <Standard_Real.hxx> |
25 | #include <Standard_Boolean.hxx> |
26 | #include <GeomAbs_Shape.hxx> |
27 | #include <Standard_Integer.hxx> |
28 | class Standard_RangeError; |
29 | class Standard_NoSuchObject; |
30 | class Geom_UndefinedDerivative; |
31 | class Geom_UndefinedValue; |
32 | class gp_Trsf; |
33 | class gp_Pnt; |
34 | class gp_Vec; |
35 | |
36 | |
37 | class Geom_Curve; |
38 | DEFINE_STANDARD_HANDLE(Geom_Curve, Geom_Geometry) |
39 | |
40 | //! The abstract class Curve describes the common |
41 | //! behavior of curves in 3D space. The Geom package |
42 | //! provides numerous concrete classes of derived |
43 | //! curves, including lines, circles, conics, Bezier or |
44 | //! BSpline curves, etc. |
45 | //! The main characteristic of these curves is that they |
46 | //! are parameterized. The Geom_Curve class shows: |
47 | //! - how to work with the parametric equation of a curve |
48 | //! in order to calculate the point of parameter u, |
49 | //! together with the vector tangent and the derivative |
50 | //! vectors of order 2, 3,..., N at this point; |
51 | //! - how to obtain general information about the curve |
52 | //! (for example, level of continuity, closed |
53 | //! characteristics, periodicity, bounds of the parameter field); |
54 | //! - how the parameter changes when a geometric |
55 | //! transformation is applied to the curve or when the |
56 | //! orientation of the curve is inverted. |
57 | //! All curves must have a geometric continuity: a curve is |
58 | //! at least "C0". Generally, this property is checked at |
59 | //! the time of construction or when the curve is edited. |
60 | //! Where this is not the case, the documentation states so explicitly. |
61 | //! Warning |
62 | //! The Geom package does not prevent the |
63 | //! construction of curves with null length or curves which |
64 | //! self-intersect. |
65 | class Geom_Curve : public Geom_Geometry |
66 | { |
67 | |
68 | public: |
69 | |
70 | |
71 | |
72 | //! Changes the direction of parametrization of <me>. |
73 | //! The "FirstParameter" and the "LastParameter" are not changed |
74 | //! but the orientation of the curve is modified. If the curve |
75 | //! is bounded the StartPoint of the initial curve becomes the |
76 | //! EndPoint of the reversed curve and the EndPoint of the initial |
77 | //! curve becomes the StartPoint of the reversed curve. |
78 | Standard_EXPORT virtual void Reverse() = 0; |
79 | |
80 | //! Returns the parameter on the reversed curve for |
81 | //! the point of parameter U on <me>. |
82 | //! |
83 | //! me->Reversed()->Value(me->ReversedParameter(U)) |
84 | //! |
85 | //! is the same point as |
86 | //! |
87 | //! me->Value(U) |
88 | Standard_EXPORT virtual Standard_Real ReversedParameter (const Standard_Real U) const = 0; |
89 | |
90 | //! Returns the parameter on the transformed curve for |
91 | //! the transform of the point of parameter U on <me>. |
92 | //! |
93 | //! me->Transformed(T)->Value(me->TransformedParameter(U,T)) |
94 | //! |
95 | //! is the same point as |
96 | //! |
97 | //! me->Value(U).Transformed(T) |
98 | //! |
99 | //! This methods returns <U> |
100 | //! |
101 | //! It can be redefined. For example on the Line. |
102 | Standard_EXPORT virtual Standard_Real TransformedParameter (const Standard_Real U, const gp_Trsf& T) const; |
103 | |
104 | //! Returns a coefficient to compute the parameter on |
105 | //! the transformed curve for the transform of the |
106 | //! point on <me>. |
107 | //! |
108 | //! Transformed(T)->Value(U * ParametricTransformation(T)) |
109 | //! |
110 | //! is the same point as |
111 | //! |
112 | //! Value(U).Transformed(T) |
113 | //! |
114 | //! This methods returns 1. |
115 | //! |
116 | //! It can be redefined. For example on the Line. |
117 | Standard_EXPORT virtual Standard_Real ParametricTransformation (const gp_Trsf& T) const; |
118 | |
119 | //! Returns a copy of <me> reversed. |
120 | Standard_EXPORT Handle(Geom_Curve) Reversed() const; |
121 | |
122 | //! Returns the value of the first parameter. |
123 | //! Warnings : |
124 | //! It can be RealFirst from package Standard |
125 | //! if the curve is infinite |
126 | Standard_EXPORT virtual Standard_Real FirstParameter() const = 0; |
127 | |
128 | //! Returns the value of the last parameter. |
129 | //! Warnings : |
130 | //! It can be RealLast from package Standard |
131 | //! if the curve is infinite |
132 | Standard_EXPORT virtual Standard_Real LastParameter() const = 0; |
133 | |
134 | //! Returns true if the curve is closed. |
135 | //! Some curves such as circle are always closed, others such as line |
136 | //! are never closed (by definition). |
137 | //! Some Curves such as OffsetCurve can be closed or not. These curves |
138 | //! are considered as closed if the distance between the first point |
139 | //! and the last point of the curve is lower or equal to the Resolution |
140 | //! from package gp wich is a fixed criterion independant of the |
141 | //! application. |
142 | Standard_EXPORT virtual Standard_Boolean IsClosed() const = 0; |
143 | |
144 | //! Is the parametrization of the curve periodic ? |
145 | //! It is possible only if the curve is closed and if the |
146 | //! following relation is satisfied : |
147 | //! for each parametric value U the distance between the point |
148 | //! P(u) and the point P (u + T) is lower or equal to Resolution |
149 | //! from package gp, T is the period and must be a constant. |
150 | //! There are three possibilities : |
151 | //! . the curve is never periodic by definition (SegmentLine) |
152 | //! . the curve is always periodic by definition (Circle) |
153 | //! . the curve can be defined as periodic (BSpline). In this case |
154 | //! a function SetPeriodic allows you to give the shape of the |
155 | //! curve. The general rule for this case is : if a curve can be |
156 | //! periodic or not the default periodicity set is non periodic |
157 | //! and you have to turn (explicitly) the curve into a periodic |
158 | //! curve if you want the curve to be periodic. |
159 | Standard_EXPORT virtual Standard_Boolean IsPeriodic() const = 0; |
160 | |
161 | //! Returns the period of this curve. |
162 | //! Exceptions Standard_NoSuchObject if this curve is not periodic. |
163 | Standard_EXPORT virtual Standard_Real Period() const; |
164 | |
165 | //! It is the global continuity of the curve |
166 | //! C0 : only geometric continuity, |
167 | //! C1 : continuity of the first derivative all along the Curve, |
168 | //! C2 : continuity of the second derivative all along the Curve, |
169 | //! C3 : continuity of the third derivative all along the Curve, |
170 | //! G1 : tangency continuity all along the Curve, |
171 | //! G2 : curvature continuity all along the Curve, |
172 | //! CN : the order of continuity is infinite. |
173 | Standard_EXPORT virtual GeomAbs_Shape Continuity() const = 0; |
174 | |
175 | //! Returns true if the degree of continuity of this curve is at least N. |
176 | //! Exceptions - Standard_RangeError if N is less than 0. |
177 | Standard_EXPORT virtual Standard_Boolean IsCN (const Standard_Integer N) const = 0; |
178 | |
179 | //! Returns in P the point of parameter U. |
180 | //! If the curve is periodic then the returned point is P(U) with |
181 | //! U = Ustart + (U - Uend) where Ustart and Uend are the |
182 | //! parametric bounds of the curve. |
183 | //! |
184 | //! Raised only for the "OffsetCurve" if it is not possible to |
185 | //! compute the current point. For example when the first |
186 | //! derivative on the basis curve and the offset direction |
187 | //! are parallel. |
188 | Standard_EXPORT virtual void D0 (const Standard_Real U, gp_Pnt& P) const = 0; |
189 | |
190 | |
191 | //! Returns the point P of parameter U and the first derivative V1. |
192 | //! Raised if the continuity of the curve is not C1. |
193 | Standard_EXPORT virtual void D1 (const Standard_Real U, gp_Pnt& P, gp_Vec& V1) const = 0; |
194 | |
195 | |
196 | //! Returns the point P of parameter U, the first and second |
197 | //! derivatives V1 and V2. |
198 | //! Raised if the continuity of the curve is not C2. |
199 | Standard_EXPORT virtual void D2 (const Standard_Real U, gp_Pnt& P, gp_Vec& V1, gp_Vec& V2) const = 0; |
200 | |
201 | |
202 | //! Returns the point P of parameter U, the first, the second |
203 | //! and the third derivative. |
204 | //! Raised if the continuity of the curve is not C3. |
205 | Standard_EXPORT virtual void D3 (const Standard_Real U, gp_Pnt& P, gp_Vec& V1, gp_Vec& V2, gp_Vec& V3) const = 0; |
206 | |
207 | |
208 | //! The returned vector gives the value of the derivative for the |
209 | //! order of derivation N. |
210 | //! Raised if the continuity of the curve is not CN. |
211 | //! |
212 | //! Raised if the derivative cannot be computed |
213 | //! easily. e.g. rational bspline and n > 3. |
214 | //! Raised if N < 1. |
215 | Standard_EXPORT virtual gp_Vec DN (const Standard_Real U, const Standard_Integer N) const = 0; |
216 | |
217 | //! Computes the point of parameter U on <me>. |
218 | //! If the curve is periodic then the returned point is P(U) with |
219 | //! U = Ustart + (U - Uend) where Ustart and Uend are the |
220 | //! parametric bounds of the curve. |
221 | //! it is implemented with D0. |
222 | //! |
223 | //! Raised only for the "OffsetCurve" if it is not possible to |
224 | //! compute the current point. For example when the first |
225 | //! derivative on the basis curve and the offset direction are parallel. |
226 | Standard_EXPORT gp_Pnt Value (const Standard_Real U) const; |
227 | |
228 | |
229 | |
230 | |
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231 | DEFINE_STANDARD_RTTIEXT(Geom_Curve,Geom_Geometry) |
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232 | |
233 | protected: |
234 | |
235 | |
236 | |
237 | |
238 | private: |
239 | |
240 | |
241 | |
242 | |
243 | }; |
244 | |
245 | |
246 | |
247 | |
248 | |
249 | |
250 | |
251 | #endif // _Geom_Curve_HeaderFile |