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1 | // Created on: 1993-03-24 |
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 _Geom2d_Curve_HeaderFile |
18 | #define _Geom2d_Curve_HeaderFile |
19 | |
20 | #include <Standard.hxx> |
21 | #include <Standard_Type.hxx> |
22 | |
23 | #include <Geom2d_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 Geom2d_UndefinedDerivative; |
31 | class Geom2d_UndefinedValue; |
32 | class gp_Trsf2d; |
33 | class gp_Pnt2d; |
34 | class gp_Vec2d; |
35 | |
36 | |
37 | class Geom2d_Curve; |
38 | DEFINE_STANDARD_HANDLE(Geom2d_Curve, Geom2d_Geometry) |
39 | |
40 | //! The abstract class Curve describes the common |
41 | //! behavior of curves in 2D space. The Geom2d |
42 | //! package provides numerous concrete classes of |
43 | //! derived curves, including lines, circles, conics, Bezier |
44 | //! or BSpline curves, etc. |
45 | //! The main characteristic of these curves is that they |
46 | //! are parameterized. The Geom2d_Curve class shows: |
47 | //! - how to work with the parametric equation of a |
48 | //! curve in order to calculate the point of parameter |
49 | //! u, together with the vector tangent and the |
50 | //! derivative 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 |
61 | //! explicitly states so. |
62 | //! Warning |
63 | //! The Geom2d package does not prevent the |
64 | //! construction of curves with null length or curves which |
65 | //! self-intersect. |
66 | class Geom2d_Curve : public Geom2d_Geometry |
67 | { |
68 | |
69 | public: |
70 | |
71 | |
72 | |
73 | //! Changes the direction of parametrization of <me>. |
74 | //! The "FirstParameter" and the "LastParameter" are not changed |
75 | //! but the orientation of the curve is modified. If the curve |
76 | //! is bounded the StartPoint of the initial curve becomes the |
77 | //! EndPoint of the reversed curve and the EndPoint of the initial |
78 | //! curve becomes the StartPoint of the reversed curve. |
79 | Standard_EXPORT virtual void Reverse() = 0; |
80 | |
81 | //! Computes the parameter on the reversed curve for |
82 | //! the point of parameter U on this curve. |
83 | //! Note: The point of parameter U on this curve is |
84 | //! identical to the point of parameter |
85 | //! ReversedParameter(U) on the reversed curve. |
86 | Standard_EXPORT virtual Standard_Real ReversedParameter (const Standard_Real U) const = 0; |
87 | |
88 | //! Computes the parameter on the curve transformed by |
89 | //! T for the point of parameter U on this curve. |
90 | //! Note: this function generally returns U but it can be |
91 | //! redefined (for example, on a line). |
92 | Standard_EXPORT virtual Standard_Real TransformedParameter (const Standard_Real U, const gp_Trsf2d& T) const; |
93 | |
94 | //! Returns the coefficient required to compute the |
95 | //! parametric transformation of this curve when |
96 | //! transformation T is applied. This coefficient is the |
97 | //! ratio between the parameter of a point on this curve |
98 | //! and the parameter of the transformed point on the |
99 | //! new curve transformed by T. |
100 | //! Note: this function generally returns 1. but it can be |
101 | //! redefined (for example, on a line). |
102 | Standard_EXPORT virtual Standard_Real ParametricTransformation (const gp_Trsf2d& T) const; |
103 | |
104 | //! Creates a reversed duplicate Changes the orientation of this curve. The first and |
105 | //! last parameters are not changed, but the parametric |
106 | //! direction of the curve is reversed. |
107 | //! If the curve is bounded: |
108 | //! - the start point of the initial curve becomes the end |
109 | //! point of the reversed curve, and |
110 | //! - the end point of the initial curve becomes the start |
111 | //! point of the reversed curve. |
112 | //! - Reversed creates a new curve. |
113 | Standard_EXPORT Handle(Geom2d_Curve) Reversed() const; |
114 | |
115 | //! Returns the value of the first parameter. |
116 | //! Warnings : |
117 | //! It can be RealFirst or RealLast from package Standard |
118 | //! if the curve is infinite |
119 | Standard_EXPORT virtual Standard_Real FirstParameter() const = 0; |
120 | |
121 | //! Value of the last parameter. |
122 | //! Warnings : |
123 | //! It can be RealFirst or RealLast from package Standard |
124 | //! if the curve is infinite |
125 | Standard_EXPORT virtual Standard_Real LastParameter() const = 0; |
126 | |
127 | //! Returns true if the curve is closed. |
128 | //! Examples : |
129 | //! Some curves such as circle are always closed, others such as line |
130 | //! are never closed (by definition). |
131 | //! Some Curves such as OffsetCurve can be closed or not. These curves |
132 | //! are considered as closed if the distance between the first point |
133 | //! and the last point of the curve is lower or equal to the Resolution |
134 | //! from package gp wich is a fixed criterion independant of the |
135 | //! application. |
136 | Standard_EXPORT virtual Standard_Boolean IsClosed() const = 0; |
137 | |
138 | |
139 | //! Returns true if the parameter of the curve is periodic. |
140 | //! It is possible only if the curve is closed and if the |
141 | //! following relation is satisfied : |
142 | //! for each parametric value U the distance between the point |
143 | //! P(u) and the point P (u + T) is lower or equal to Resolution |
144 | //! from package gp, T is the period and must be a constant. |
145 | //! There are three possibilities : |
146 | //! . the curve is never periodic by definition (SegmentLine) |
147 | //! . the curve is always periodic by definition (Circle) |
148 | //! . the curve can be defined as periodic (BSpline). In this case |
149 | //! a function SetPeriodic allows you to give the shape of the |
150 | //! curve. The general rule for this case is : if a curve can be |
151 | //! periodic or not the default periodicity set is non periodic |
152 | //! and you have to turn (explicitly) the curve into a periodic |
153 | //! curve if you want the curve to be periodic. |
154 | Standard_EXPORT virtual Standard_Boolean IsPeriodic() const = 0; |
155 | |
156 | //! Returns thne period of this curve. |
157 | //! raises if the curve is not periodic |
158 | Standard_EXPORT virtual Standard_Real Period() const; |
159 | |
160 | |
161 | //! It is the global continuity of the curve : |
162 | //! C0 : only geometric continuity, |
163 | //! C1 : continuity of the first derivative all along the Curve, |
164 | //! C2 : continuity of the second derivative all along the Curve, |
165 | //! C3 : continuity of the third derivative all along the Curve, |
166 | //! G1 : tangency continuity all along the Curve, |
167 | //! G2 : curvature continuity all along the Curve, |
168 | //! CN : the order of continuity is infinite. |
169 | Standard_EXPORT virtual GeomAbs_Shape Continuity() const = 0; |
170 | |
171 | //! Returns true if the degree of continuity of this curve is at least N. |
172 | //! Exceptions Standard_RangeError if N is less than 0. |
173 | Standard_EXPORT virtual Standard_Boolean IsCN (const Standard_Integer N) const = 0; |
174 | |
175 | //! Returns in P the point of parameter U. |
176 | //! If the curve is periodic then the returned point is P(U) with |
177 | //! U = Ustart + (U - Uend) where Ustart and Uend are the |
178 | //! parametric bounds of the curve. |
179 | //! |
180 | //! Raised only for the "OffsetCurve" if it is not possible to |
181 | //! compute the current point. For example when the first |
182 | //! derivative on the basis curve and the offset direction |
183 | //! are parallel. |
184 | Standard_EXPORT virtual void D0 (const Standard_Real U, gp_Pnt2d& P) const = 0; |
185 | |
186 | |
187 | //! Returns the point P of parameter U and the first derivative V1. |
188 | //! Raised if the continuity of the curve is not C1. |
189 | Standard_EXPORT virtual void D1 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1) const = 0; |
190 | |
191 | |
192 | //! Returns the point P of parameter U, the first and second |
193 | //! derivatives V1 and V2. |
194 | //! Raised if the continuity of the curve is not C2. |
195 | Standard_EXPORT virtual void D2 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1, gp_Vec2d& V2) const = 0; |
196 | |
197 | |
198 | //! Returns the point P of parameter U, the first, the second |
199 | //! and the third derivative. |
200 | //! Raised if the continuity of the curve is not C3. |
201 | Standard_EXPORT virtual void D3 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1, gp_Vec2d& V2, gp_Vec2d& V3) const = 0; |
202 | |
203 | //! For the point of parameter U of this curve, computes |
204 | //! the vector corresponding to the Nth derivative. |
205 | //! Exceptions |
206 | //! StdFail_UndefinedDerivative if: |
207 | //! - the continuity of the curve is not "CN", or |
208 | //! - the derivative vector cannot be computed easily; |
209 | //! this is the case with specific types of curve (for |
210 | //! example, a rational BSpline curve where N is greater than 3). |
211 | //! Standard_RangeError if N is less than 1. |
212 | Standard_EXPORT virtual gp_Vec2d DN (const Standard_Real U, const Standard_Integer N) const = 0; |
213 | |
214 | //! Computes the point of parameter U on <me>. |
215 | //! If the curve is periodic then the returned point is P(U) with |
216 | //! U = Ustart + (U - Uend) where Ustart and Uend are the |
217 | //! parametric bounds of the curve. |
218 | //! |
219 | //! it is implemented with D0. |
220 | //! |
221 | //! Raised only for the "OffsetCurve" if it is not possible to |
222 | //! compute the current point. For example when the first |
223 | //! derivative on the basis curve and the offset direction |
224 | //! are parallel. |
225 | Standard_EXPORT gp_Pnt2d Value (const Standard_Real U) const; |
226 | |
227 | |
228 | |
229 | |
230 | DEFINE_STANDARD_RTTI(Geom2d_Curve,Geom2d_Geometry) |
231 | |
232 | protected: |
233 | |
234 | |
235 | |
236 | |
237 | private: |
238 | |
239 | |
240 | |
241 | |
242 | }; |
243 | |
244 | |
245 | |
246 | |
247 | |
248 | |
249 | |
250 | #endif // _Geom2d_Curve_HeaderFile |