42cf5bc1 |
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> |
28 | class Geom2d_Curve; |
29 | class Standard_ConstructionError; |
30 | class Standard_RangeError; |
31 | class Standard_NoSuchObject; |
32 | class Geom2d_UndefinedDerivative; |
33 | class Geom2d_UndefinedValue; |
34 | class Standard_NotImplemented; |
35 | class gp_Pnt2d; |
36 | class gp_Vec2d; |
37 | class gp_Trsf2d; |
38 | class Geom2d_Geometry; |
39 | |
40 | |
41 | class Geom2d_OffsetCurve; |
42 | DEFINE_STANDARD_HANDLE(Geom2d_OffsetCurve, Geom2d_Curve) |
43 | |
44 | |
45 | //! This class implements the basis services for the creation, |
46 | //! edition, modification and evaluation of planar offset curve. |
47 | //! The offset curve is obtained by offsetting by distance along |
48 | //! the normal to a basis curve defined in 2D space. |
49 | //! The offset curve in this package can be a self intersecting |
50 | //! curve even if the basis curve does not self-intersect. |
51 | //! The self intersecting portions are not deleted at the |
52 | //! construction time. |
53 | //! An offset curve is a curve at constant distance (Offset) from a |
54 | //! basis curve and the offset curve takes its parametrization from |
55 | //! the basis curve. The Offset curve is in the direction of the |
56 | //! normal to the basis curve N. |
57 | //! The distance offset may be positive or negative to indicate the |
58 | //! preferred side of the curve : |
59 | //! . distance offset >0 => the curve is in the direction of N |
60 | //! . distance offset >0 => the curve is in the direction of - N |
61 | //! On the Offset curve : |
62 | //! Value(u) = BasisCurve.Value(U) + (Offset * (T ^ Z)) / ||T ^ Z|| |
63 | //! where T is the tangent vector to the basis curve and Z the |
64 | //! direction of the normal vector to the plane of the curve, |
65 | //! N = T ^ Z defines the offset direction and should not have |
66 | //! null length. |
67 | //! |
68 | //! Warnings : |
69 | //! In this package we suppose that the continuity of the offset |
70 | //! curve is one degree less than the continuity of the |
71 | //! basis curve and we don't check that at any point ||T^Z|| != 0.0 |
72 | //! |
73 | //! So to evaluate the curve it is better to check that the offset |
74 | //! curve is well defined at any point because an exception could |
75 | //! be raised. The check is not done in this package at the creation |
76 | //! of the offset curve because the control needs the use of an |
77 | //! algorithm which cannot be implemented in this package. |
78 | //! The OffsetCurve is closed if the first point and the last point |
79 | //! are the same (The distance between these two points is lower or |
80 | //! equal to the Resolution sea package gp) . The OffsetCurve can be |
81 | //! closed even if the basis curve is not closed. |
82 | class Geom2d_OffsetCurve : public Geom2d_Curve |
83 | { |
84 | |
85 | public: |
86 | |
87 | |
88 | //! Constructs a curve offset from the basis curve C, |
89 | //! where Offset is the distance between the offset |
90 | //! curve and the basis curve at any point. |
91 | //! A point on the offset curve is built by measuring the |
92 | //! offset value along a normal vector at a point on C. |
93 | //! This normal vector is obtained by rotating the |
94 | //! vector tangential to C at 90 degrees in the |
95 | //! anti-trigonometric sense. The side of C on which |
96 | //! the offset value is measured is indicated by this |
97 | //! normal vector if Offset is positive, or in the inverse |
98 | //! sense if Offset is negative. |
99 | //! If isNotCheckC0 = TRUE checking if basis curve has C0-continuity |
100 | //! is not made. |
101 | //! Warnings : |
102 | //! In this package the entities are not shared. The OffsetCurve is |
103 | //! built with a copy of the curve C. So when C is modified the |
104 | //! OffsetCurve is not modified |
105 | //! Warning! if isNotCheckC0 = false, |
106 | //! ConstructionError raised if the basis curve C is not at least C1. |
107 | //! No check is done to know if ||V^Z|| != 0.0 at any point. |
108 | Standard_EXPORT Geom2d_OffsetCurve(const Handle(Geom2d_Curve)& C, const Standard_Real Offset, const Standard_Boolean isNotCheckC0 = Standard_False); |
109 | |
110 | //! Changes the direction of parametrization of <me>. |
111 | //! As a result: |
112 | //! - the basis curve is reversed, |
113 | //! - the start point of the initial curve becomes the end |
114 | //! point of the reversed curve, |
115 | //! - the end point of the initial curve becomes the start |
116 | //! point of the reversed curve, and |
117 | //! - the first and last parameters are recomputed. |
118 | Standard_EXPORT void Reverse(); |
119 | |
120 | //! Computes the parameter on the reversed curve for |
121 | //! the point of parameter U on this offset curve. |
122 | Standard_EXPORT Standard_Real ReversedParameter (const Standard_Real U) const; |
123 | |
124 | //! Changes this offset curve by assigning C as the |
125 | //! basis curve from which it is built. |
126 | //! If isNotCheckC0 = TRUE checking if basis curve has C0-continuity |
127 | //! is not made. |
128 | //! Exceptions |
129 | //! if isNotCheckC0 = false, |
130 | //! Standard_ConstructionError if the curve C is not at least "C1" continuous. |
131 | Standard_EXPORT void SetBasisCurve (const Handle(Geom2d_Curve)& C, const Standard_Boolean isNotCheckC0 = Standard_False); |
132 | |
133 | //! Changes this offset curve by assigning D as the offset value. |
134 | Standard_EXPORT void SetOffsetValue (const Standard_Real D); |
135 | |
136 | //! Returns the basis curve of this offset curve. The basis curve can be an offset curve. |
137 | Standard_EXPORT Handle(Geom2d_Curve) BasisCurve() const; |
138 | |
139 | |
140 | //! Continuity of the Offset curve : |
141 | //! C0 : only geometric continuity, |
142 | //! C1 : continuity of the first derivative all along the Curve, |
143 | //! C2 : continuity of the second derivative all along the Curve, |
144 | //! C3 : continuity of the third derivative all along the Curve, |
145 | //! G1 : tangency continuity all along the Curve, |
146 | //! G2 : curvature continuity all along the Curve, |
147 | //! CN : the order of continuity is infinite. |
148 | //! Warnings : |
149 | //! Returns the continuity of the basis curve - 1. |
150 | //! The offset curve must have a unique normal direction defined |
151 | //! at any point. |
152 | //! Value and derivatives |
153 | //! |
154 | //! Warnings : |
155 | //! The exception UndefinedValue or UndefinedDerivative is |
156 | //! raised if it is not possible to compute a unique offset |
157 | //! direction. |
158 | //! If T is the first derivative with not null length and |
159 | //! Z the direction normal to the plane of the curve, the |
160 | //! relation ||T(U) ^ Z|| != 0 must be satisfied to evaluate |
161 | //! the offset curve. |
162 | //! No check is done at the creation time and we suppose |
163 | //! in this package that the offset curve is well defined. |
164 | Standard_EXPORT GeomAbs_Shape Continuity() const; |
165 | |
166 | //! Warning! this should not be called |
167 | //! if the basis curve is not at least C1. Nevertheless |
168 | //! if used on portion where the curve is C1, it is OK |
169 | Standard_EXPORT void D0 (const Standard_Real U, gp_Pnt2d& P) const; |
170 | |
171 | //! Warning! this should not be called |
172 | //! if the continuity of the basis curve is not C2. |
173 | //! Nevertheless, it's OK to use it on portion |
174 | //! where the curve is C2 |
175 | Standard_EXPORT void D1 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1) const; |
176 | |
177 | //! Warning! This should not be called |
178 | //! if the continuity of the basis curve is not C3. |
179 | //! Nevertheless, it's OK to use it on portion |
180 | //! where the curve is C3 |
181 | Standard_EXPORT void D2 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1, gp_Vec2d& V2) const; |
182 | |
183 | //! Warning! This should not be called |
184 | //! if the continuity of the basis curve is not C4. |
185 | //! Nevertheless, it's OK to use it on portion |
186 | //! where the curve is C4 |
187 | Standard_EXPORT void D3 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1, gp_Vec2d& V2, gp_Vec2d& V3) const; |
188 | |
189 | //! The returned vector gives the value of the derivative |
190 | //! for the order of derivation N. |
191 | //! Warning! this should not be called |
192 | //! raises UndefunedDerivative if the continuity of the basis curve is not CN+1. |
193 | //! Nevertheless, it's OK to use it on portion |
194 | //! where the curve is CN+1 |
195 | //! raises RangeError if N < 1. |
196 | //! raises NotImplemented if N > 3. |
197 | //! The following functions compute the value and derivatives |
198 | //! on the offset curve and returns the derivatives on the |
199 | //! basis curve too. |
200 | //! The computation of the value and derivatives on the basis |
201 | //! curve are used to evaluate the offset curve |
202 | //! Warnings : |
203 | //! The exception UndefinedValue or UndefinedDerivative is |
204 | //! raised if it is not possible to compute a unique offset direction. |
205 | Standard_EXPORT gp_Vec2d DN (const Standard_Real U, const Standard_Integer N) const; |
206 | |
207 | //! Warning! this should not be called |
208 | //! if the basis curve is not at least C1. Nevertheless |
209 | //! if used on portion where the curve is C1, it is OK |
210 | Standard_EXPORT void Value (const Standard_Real U, gp_Pnt2d& P, gp_Pnt2d& Pbasis, gp_Vec2d& V1basis) const; |
211 | |
212 | //! Warning! this should not be called |
213 | //! if the continuity of the basis curve is not C1. |
214 | //! Nevertheless, it's OK to use it on portion |
215 | //! where the curve is C1 |
216 | Standard_EXPORT void D1 (const Standard_Real U, gp_Pnt2d& P, gp_Pnt2d& Pbasis, gp_Vec2d& V1, gp_Vec2d& V1basis, gp_Vec2d& V2basis) const; |
217 | |
218 | //! Warning! this should not be called |
219 | //! if the continuity of the basis curve is not C3. |
220 | //! Nevertheless, it's OK to use it on portion |
221 | //! where the curve is C3 |
222 | Standard_EXPORT void D2 (const Standard_Real U, gp_Pnt2d& P, gp_Pnt2d& Pbasis, gp_Vec2d& V1, gp_Vec2d& V2, gp_Vec2d& V1basis, gp_Vec2d& V2basis, gp_Vec2d& V3basis) const; |
223 | |
224 | Standard_EXPORT Standard_Real FirstParameter() const; |
225 | |
226 | //! Returns the value of the first or last parameter of this |
227 | //! offset curve. The first parameter corresponds to the |
228 | //! start point of the curve. The last parameter |
229 | //! corresponds to the end point. |
230 | //! Note: the first and last parameters of this offset curve |
231 | //! are also the ones of its basis curve. |
232 | Standard_EXPORT Standard_Real LastParameter() const; |
233 | |
234 | //! Returns the offset value of this offset curve. |
235 | Standard_EXPORT Standard_Real Offset() const; |
236 | |
237 | |
238 | //! Returns True if the distance between the start point |
239 | //! and the end point of the curve is lower or equal to |
240 | //! Resolution from package gp. |
241 | Standard_EXPORT Standard_Boolean IsClosed() const; |
242 | |
243 | //! Is the order of continuity of the curve N ? |
244 | //! Warnings : |
245 | //! This method answer True if the continuity of the basis curve |
246 | //! is N + 1. We suppose in this class that a normal direction |
247 | //! to the basis curve (used to compute the offset curve) is |
248 | //! defined at any point on the basis curve. |
249 | //! Raised if N < 0. |
250 | Standard_EXPORT Standard_Boolean IsCN (const Standard_Integer N) const; |
251 | |
252 | //! Is the parametrization of a curve is periodic ? |
253 | //! If the basis curve is a circle or an ellipse the corresponding |
254 | //! OffsetCurve is periodic. If the basis curve can't be periodic |
255 | //! (for example BezierCurve) the OffsetCurve can't be periodic. |
256 | Standard_EXPORT Standard_Boolean IsPeriodic() const; |
257 | |
258 | //! Returns the period of this offset curve, i.e. the period |
259 | //! of the basis curve of this offset curve. |
260 | //! Exceptions |
261 | //! Standard_NoSuchObject if the basis curve is not periodic. |
262 | Standard_EXPORT virtual Standard_Real Period() const Standard_OVERRIDE; |
263 | |
264 | //! Applies the transformation T to this offset curve. |
265 | //! Note: the basis curve is also modified. |
266 | Standard_EXPORT void Transform (const gp_Trsf2d& T); |
267 | |
268 | //! Returns the parameter on the transformed curve for |
269 | //! the transform of the point of parameter U on <me>. |
270 | //! |
271 | //! me->Transformed(T)->Value(me->TransformedParameter(U,T)) |
272 | //! |
273 | //! is the same point as |
274 | //! |
275 | //! me->Value(U).Transformed(T) |
276 | //! |
277 | //! This methods calls the basis curve method. |
278 | Standard_EXPORT virtual Standard_Real TransformedParameter (const Standard_Real U, const gp_Trsf2d& T) const Standard_OVERRIDE; |
279 | |
280 | //! Returns a coefficient to compute the parameter on |
281 | //! the transformed curve for the transform of the |
282 | //! point on <me>. |
283 | //! |
284 | //! Transformed(T)->Value(U * ParametricTransformation(T)) |
285 | //! |
286 | //! is the same point as |
287 | //! |
288 | //! Value(U).Transformed(T) |
289 | //! |
290 | //! This methods calls the basis curve method. |
291 | Standard_EXPORT virtual Standard_Real ParametricTransformation (const gp_Trsf2d& T) const Standard_OVERRIDE; |
292 | |
293 | //! Creates a new object, which is a copy of this offset curve. |
294 | Standard_EXPORT Handle(Geom2d_Geometry) Copy() const; |
295 | |
296 | //! Returns continuity of the basis curve. |
297 | Standard_EXPORT GeomAbs_Shape GetBasisCurveContinuity() const; |
298 | |
299 | |
300 | |
301 | |
302 | DEFINE_STANDARD_RTTI(Geom2d_OffsetCurve,Geom2d_Curve) |
303 | |
304 | protected: |
305 | |
306 | |
307 | |
308 | |
309 | private: |
310 | |
311 | |
312 | Handle(Geom2d_Curve) basisCurve; |
313 | Standard_Real offsetValue; |
314 | GeomAbs_Shape myBasisCurveContinuity; |
315 | |
316 | |
317 | }; |
318 | |
319 | |
320 | |
321 | |
322 | |
323 | |
324 | |
325 | #endif // _Geom2d_OffsetCurve_HeaderFile |