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1 | // Created on: 1993-03-24 |
2 | // Created by: Philippe DAUTRY |
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_OffsetCurve_HeaderFile |
18 | #define _Geom2d_OffsetCurve_HeaderFile |
19 | |
20 | #include <Standard.hxx> |
21 | #include <Standard_Type.hxx> |
22 | |
23 | #include <Standard_Real.hxx> |
24 | #include <GeomAbs_Shape.hxx> |
25 | #include <Geom2d_Curve.hxx> |
26 | #include <Standard_Boolean.hxx> |
27 | #include <Standard_Integer.hxx> |
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28 | #include <Geom2dEvaluator_OffsetCurve.hxx> |
29 | |
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30 | class Geom2d_Curve; |
31 | class Standard_ConstructionError; |
32 | class Standard_RangeError; |
33 | class Standard_NoSuchObject; |
34 | class Geom2d_UndefinedDerivative; |
35 | class Geom2d_UndefinedValue; |
36 | class Standard_NotImplemented; |
37 | class gp_Pnt2d; |
38 | class gp_Vec2d; |
39 | class gp_Trsf2d; |
40 | class Geom2d_Geometry; |
41 | |
42 | |
43 | class Geom2d_OffsetCurve; |
44 | DEFINE_STANDARD_HANDLE(Geom2d_OffsetCurve, Geom2d_Curve) |
45 | |
46 | |
47 | //! This class implements the basis services for the creation, |
48 | //! edition, modification and evaluation of planar offset curve. |
49 | //! The offset curve is obtained by offsetting by distance along |
50 | //! the normal to a basis curve defined in 2D space. |
51 | //! The offset curve in this package can be a self intersecting |
52 | //! curve even if the basis curve does not self-intersect. |
53 | //! The self intersecting portions are not deleted at the |
54 | //! construction time. |
55 | //! An offset curve is a curve at constant distance (Offset) from a |
56 | //! basis curve and the offset curve takes its parametrization from |
57 | //! the basis curve. The Offset curve is in the direction of the |
58 | //! normal to the basis curve N. |
59 | //! The distance offset may be positive or negative to indicate the |
60 | //! preferred side of the curve : |
61 | //! . distance offset >0 => the curve is in the direction of N |
62 | //! . distance offset >0 => the curve is in the direction of - N |
63 | //! On the Offset curve : |
64 | //! Value(u) = BasisCurve.Value(U) + (Offset * (T ^ Z)) / ||T ^ Z|| |
65 | //! where T is the tangent vector to the basis curve and Z the |
66 | //! direction of the normal vector to the plane of the curve, |
67 | //! N = T ^ Z defines the offset direction and should not have |
68 | //! null length. |
69 | //! |
70 | //! Warnings : |
71 | //! In this package we suppose that the continuity of the offset |
72 | //! curve is one degree less than the continuity of the |
73 | //! basis curve and we don't check that at any point ||T^Z|| != 0.0 |
74 | //! |
75 | //! So to evaluate the curve it is better to check that the offset |
76 | //! curve is well defined at any point because an exception could |
77 | //! be raised. The check is not done in this package at the creation |
78 | //! of the offset curve because the control needs the use of an |
79 | //! algorithm which cannot be implemented in this package. |
80 | //! The OffsetCurve is closed if the first point and the last point |
81 | //! are the same (The distance between these two points is lower or |
82 | //! equal to the Resolution sea package gp) . The OffsetCurve can be |
83 | //! closed even if the basis curve is not closed. |
84 | class Geom2d_OffsetCurve : public Geom2d_Curve |
85 | { |
86 | |
87 | public: |
88 | |
89 | |
90 | //! Constructs a curve offset from the basis curve C, |
91 | //! where Offset is the distance between the offset |
92 | //! curve and the basis curve at any point. |
93 | //! A point on the offset curve is built by measuring the |
94 | //! offset value along a normal vector at a point on C. |
95 | //! This normal vector is obtained by rotating the |
96 | //! vector tangential to C at 90 degrees in the |
97 | //! anti-trigonometric sense. The side of C on which |
98 | //! the offset value is measured is indicated by this |
99 | //! normal vector if Offset is positive, or in the inverse |
100 | //! sense if Offset is negative. |
101 | //! If isNotCheckC0 = TRUE checking if basis curve has C0-continuity |
102 | //! is not made. |
103 | //! Warnings : |
104 | //! In this package the entities are not shared. The OffsetCurve is |
105 | //! built with a copy of the curve C. So when C is modified the |
106 | //! OffsetCurve is not modified |
107 | //! Warning! if isNotCheckC0 = false, |
108 | //! ConstructionError raised if the basis curve C is not at least C1. |
109 | //! No check is done to know if ||V^Z|| != 0.0 at any point. |
110 | Standard_EXPORT Geom2d_OffsetCurve(const Handle(Geom2d_Curve)& C, const Standard_Real Offset, const Standard_Boolean isNotCheckC0 = Standard_False); |
111 | |
112 | //! Changes the direction of parametrization of <me>. |
113 | //! As a result: |
114 | //! - the basis curve is reversed, |
115 | //! - the start point of the initial curve becomes the end |
116 | //! point of the reversed curve, |
117 | //! - the end point of the initial curve becomes the start |
118 | //! point of the reversed curve, and |
119 | //! - the first and last parameters are recomputed. |
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120 | Standard_EXPORT void Reverse() Standard_OVERRIDE; |
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121 | |
122 | //! Computes the parameter on the reversed curve for |
123 | //! the point of parameter U on this offset curve. |
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124 | Standard_EXPORT Standard_Real ReversedParameter (const Standard_Real U) const Standard_OVERRIDE; |
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125 | |
126 | //! Changes this offset curve by assigning C as the |
127 | //! basis curve from which it is built. |
128 | //! If isNotCheckC0 = TRUE checking if basis curve has C0-continuity |
129 | //! is not made. |
130 | //! Exceptions |
131 | //! if isNotCheckC0 = false, |
132 | //! Standard_ConstructionError if the curve C is not at least "C1" continuous. |
133 | Standard_EXPORT void SetBasisCurve (const Handle(Geom2d_Curve)& C, const Standard_Boolean isNotCheckC0 = Standard_False); |
134 | |
135 | //! Changes this offset curve by assigning D as the offset value. |
136 | Standard_EXPORT void SetOffsetValue (const Standard_Real D); |
137 | |
138 | //! Returns the basis curve of this offset curve. The basis curve can be an offset curve. |
139 | Standard_EXPORT Handle(Geom2d_Curve) BasisCurve() const; |
140 | |
141 | |
142 | //! Continuity of the Offset curve : |
143 | //! C0 : only geometric continuity, |
144 | //! C1 : continuity of the first derivative all along the Curve, |
145 | //! C2 : continuity of the second derivative all along the Curve, |
146 | //! C3 : continuity of the third derivative all along the Curve, |
147 | //! G1 : tangency continuity all along the Curve, |
148 | //! G2 : curvature continuity all along the Curve, |
149 | //! CN : the order of continuity is infinite. |
150 | //! Warnings : |
151 | //! Returns the continuity of the basis curve - 1. |
152 | //! The offset curve must have a unique normal direction defined |
153 | //! at any point. |
154 | //! Value and derivatives |
155 | //! |
156 | //! Warnings : |
157 | //! The exception UndefinedValue or UndefinedDerivative is |
158 | //! raised if it is not possible to compute a unique offset |
159 | //! direction. |
160 | //! If T is the first derivative with not null length and |
161 | //! Z the direction normal to the plane of the curve, the |
162 | //! relation ||T(U) ^ Z|| != 0 must be satisfied to evaluate |
163 | //! the offset curve. |
164 | //! No check is done at the creation time and we suppose |
165 | //! in this package that the offset curve is well defined. |
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166 | Standard_EXPORT GeomAbs_Shape Continuity() const Standard_OVERRIDE; |
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167 | |
168 | //! Warning! this should not be called |
169 | //! if the basis curve is not at least C1. Nevertheless |
170 | //! if used on portion where the curve is C1, it is OK |
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171 | Standard_EXPORT void D0 (const Standard_Real U, gp_Pnt2d& P) const Standard_OVERRIDE; |
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172 | |
173 | //! Warning! this should not be called |
174 | //! if the continuity of the basis curve is not C2. |
175 | //! Nevertheless, it's OK to use it on portion |
176 | //! where the curve is C2 |
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177 | Standard_EXPORT void D1 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1) const Standard_OVERRIDE; |
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178 | |
179 | //! Warning! This should not be called |
180 | //! if the continuity of the basis curve is not C3. |
181 | //! Nevertheless, it's OK to use it on portion |
182 | //! where the curve is C3 |
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183 | Standard_EXPORT void D2 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1, gp_Vec2d& V2) const Standard_OVERRIDE; |
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184 | |
185 | //! Warning! This should not be called |
186 | //! if the continuity of the basis curve is not C4. |
187 | //! Nevertheless, it's OK to use it on portion |
188 | //! where the curve is C4 |
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189 | Standard_EXPORT void D3 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1, gp_Vec2d& V2, gp_Vec2d& V3) const Standard_OVERRIDE; |
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190 | |
191 | //! The returned vector gives the value of the derivative |
192 | //! for the order of derivation N. |
193 | //! Warning! this should not be called |
194 | //! raises UndefunedDerivative if the continuity of the basis curve is not CN+1. |
195 | //! Nevertheless, it's OK to use it on portion |
196 | //! where the curve is CN+1 |
197 | //! raises RangeError if N < 1. |
198 | //! raises NotImplemented if N > 3. |
199 | //! The following functions compute the value and derivatives |
200 | //! on the offset curve and returns the derivatives on the |
201 | //! basis curve too. |
202 | //! The computation of the value and derivatives on the basis |
203 | //! curve are used to evaluate the offset curve |
204 | //! Warnings : |
205 | //! The exception UndefinedValue or UndefinedDerivative is |
206 | //! raised if it is not possible to compute a unique offset direction. |
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207 | Standard_EXPORT gp_Vec2d DN (const Standard_Real U, const Standard_Integer N) const Standard_OVERRIDE; |
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208 | |
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209 | //! Returns the value of the first parameter of this |
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210 | //! offset curve. The first parameter corresponds to the |
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211 | //! start point of the curve. |
212 | //! Note: the first and last parameters of this offset curve |
213 | //! are also the ones of its basis curve. |
214 | Standard_EXPORT Standard_Real FirstParameter() const Standard_OVERRIDE; |
215 | |
216 | //! Returns the value of the last parameter of this |
217 | //! offset curve. The last parameter |
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218 | //! corresponds to the end point. |
219 | //! Note: the first and last parameters of this offset curve |
220 | //! are also the ones of its basis curve. |
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221 | Standard_EXPORT Standard_Real LastParameter() const Standard_OVERRIDE; |
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222 | |
223 | //! Returns the offset value of this offset curve. |
224 | Standard_EXPORT Standard_Real Offset() const; |
225 | |
226 | |
227 | //! Returns True if the distance between the start point |
228 | //! and the end point of the curve is lower or equal to |
229 | //! Resolution from package gp. |
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230 | Standard_EXPORT Standard_Boolean IsClosed() const Standard_OVERRIDE; |
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231 | |
232 | //! Is the order of continuity of the curve N ? |
233 | //! Warnings : |
234 | //! This method answer True if the continuity of the basis curve |
235 | //! is N + 1. We suppose in this class that a normal direction |
236 | //! to the basis curve (used to compute the offset curve) is |
237 | //! defined at any point on the basis curve. |
238 | //! Raised if N < 0. |
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239 | Standard_EXPORT Standard_Boolean IsCN (const Standard_Integer N) const Standard_OVERRIDE; |
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240 | |
241 | //! Is the parametrization of a curve is periodic ? |
242 | //! If the basis curve is a circle or an ellipse the corresponding |
243 | //! OffsetCurve is periodic. If the basis curve can't be periodic |
244 | //! (for example BezierCurve) the OffsetCurve can't be periodic. |
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245 | Standard_EXPORT Standard_Boolean IsPeriodic() const Standard_OVERRIDE; |
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246 | |
247 | //! Returns the period of this offset curve, i.e. the period |
248 | //! of the basis curve of this offset curve. |
249 | //! Exceptions |
250 | //! Standard_NoSuchObject if the basis curve is not periodic. |
251 | Standard_EXPORT virtual Standard_Real Period() const Standard_OVERRIDE; |
252 | |
253 | //! Applies the transformation T to this offset curve. |
254 | //! Note: the basis curve is also modified. |
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255 | Standard_EXPORT void Transform (const gp_Trsf2d& T) Standard_OVERRIDE; |
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256 | |
257 | //! Returns the parameter on the transformed curve for |
258 | //! the transform of the point of parameter U on <me>. |
259 | //! |
260 | //! me->Transformed(T)->Value(me->TransformedParameter(U,T)) |
261 | //! |
262 | //! is the same point as |
263 | //! |
264 | //! me->Value(U).Transformed(T) |
265 | //! |
266 | //! This methods calls the basis curve method. |
267 | Standard_EXPORT virtual Standard_Real TransformedParameter (const Standard_Real U, const gp_Trsf2d& T) const Standard_OVERRIDE; |
268 | |
269 | //! Returns a coefficient to compute the parameter on |
270 | //! the transformed curve for the transform of the |
271 | //! point on <me>. |
272 | //! |
273 | //! Transformed(T)->Value(U * ParametricTransformation(T)) |
274 | //! |
275 | //! is the same point as |
276 | //! |
277 | //! Value(U).Transformed(T) |
278 | //! |
279 | //! This methods calls the basis curve method. |
280 | Standard_EXPORT virtual Standard_Real ParametricTransformation (const gp_Trsf2d& T) const Standard_OVERRIDE; |
281 | |
282 | //! Creates a new object, which is a copy of this offset curve. |
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283 | Standard_EXPORT Handle(Geom2d_Geometry) Copy() const Standard_OVERRIDE; |
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284 | |
285 | //! Returns continuity of the basis curve. |
286 | Standard_EXPORT GeomAbs_Shape GetBasisCurveContinuity() const; |
287 | |
288 | |
289 | |
290 | |
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291 | DEFINE_STANDARD_RTTIEXT(Geom2d_OffsetCurve,Geom2d_Curve) |
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292 | |
293 | protected: |
294 | |
295 | |
296 | |
297 | |
298 | private: |
299 | |
300 | |
301 | Handle(Geom2d_Curve) basisCurve; |
302 | Standard_Real offsetValue; |
303 | GeomAbs_Shape myBasisCurveContinuity; |
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304 | Handle(Geom2dEvaluator_OffsetCurve) myEvaluator; |
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305 | |
306 | }; |
307 | |
308 | |
309 | |
310 | |
311 | |
312 | |
313 | |
314 | #endif // _Geom2d_OffsetCurve_HeaderFile |