1 // Created on: 1993-03-10
3 // Copyright (c) 1993-1999 Matra Datavision
4 // Copyright (c) 1999-2014 OPEN CASCADE SAS
6 // This file is part of Open CASCADE Technology software library.
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.
14 // Alternatively, this file may be used under the terms of Open CASCADE
15 // commercial license or contractual agreement.
17 #ifndef _Geom_Conic_HeaderFile
18 #define _Geom_Conic_HeaderFile
21 #include <Geom_Curve.hxx>
24 DEFINE_STANDARD_HANDLE(Geom_Conic, Geom_Curve)
26 //! The abstract class Conic describes the common
27 //! behavior of conic curves in 3D space and, in
28 //! particular, their general characteristics. The Geom
29 //! package provides four concrete classes of conics:
30 //! Geom_Circle, Geom_Ellipse, Geom_Hyperbola and Geom_Parabola.
31 //! A conic is positioned in space with a right-handed
32 //! coordinate system (gp_Ax2 object), where:
33 //! - the origin is the center of the conic (or the apex in
34 //! the case of a parabola),
35 //! - the origin, "X Direction" and "Y Direction" define the
36 //! plane of the conic.
37 //! This coordinate system is the local coordinate
38 //! system of the conic.
39 //! The "main Direction" of this coordinate system is the
40 //! vector normal to the plane of the conic. The axis, of
41 //! which the origin and unit vector are respectively the
42 //! origin and "main Direction" of the local coordinate
43 //! system, is termed the "Axis" or "main Axis" of the conic.
44 //! The "main Direction" of the local coordinate system
45 //! gives an explicit orientation to the conic, determining
46 //! the direction in which the parameter increases along
47 //! the conic. The "X Axis" of the local coordinate system
48 //! also defines the origin of the parameter of the conic.
49 class Geom_Conic : public Geom_Curve
53 //! Changes the orientation of the conic's plane. The normal
54 //! axis to the plane is A1. The XAxis and the YAxis are recomputed.
56 //! raised if the A1 is parallel to the XAxis of the conic.
57 void SetAxis (const gp_Ax1& theA1) { pos.SetAxis(theA1); }
59 //! changes the location point of the conic.
60 void SetLocation (const gp_Pnt& theP) { pos.SetLocation(theP); }
62 //! changes the local coordinate system of the conic.
63 void SetPosition (const gp_Ax2& theA2) { pos = theA2; }
65 //! Returns the "main Axis" of this conic. This axis is
66 //! normal to the plane of the conic.
67 const gp_Ax1& Axis() const { return pos.Axis(); }
69 //! Returns the location point of the conic.
70 //! For the circle, the ellipse and the hyperbola it is the center of
71 //! the conic. For the parabola it is the Apex of the parabola.
72 const gp_Pnt& Location() const { return pos.Location(); }
74 //! Returns the local coordinates system of the conic.
75 //! The main direction of the Axis2Placement is normal to the
76 //! plane of the conic. The X direction of the Axis2placement
77 //! is in the plane of the conic and corresponds to the origin
78 //! for the conic's parametric value u.
79 const gp_Ax2& Position() const { return pos; }
81 //! Returns the eccentricity value of the conic e.
82 //! e = 0 for a circle
83 //! 0 < e < 1 for an ellipse (e = 0 if MajorRadius = MinorRadius)
84 //! e > 1 for a hyperbola
85 //! e = 1 for a parabola
87 //! Standard_DomainError in the case of a hyperbola if
88 //! its major radius is null.
89 virtual Standard_Real Eccentricity() const = 0;
91 //! Returns the XAxis of the conic.
92 //! This axis defines the origin of parametrization of the conic.
93 //! This axis is perpendicular to the Axis of the conic.
94 //! This axis and the Yaxis define the plane of the conic.
95 Standard_EXPORT gp_Ax1 XAxis() const;
98 //! Returns the YAxis of the conic.
99 //! The YAxis is perpendicular to the Xaxis.
100 //! This axis and the Xaxis define the plane of the conic.
101 Standard_EXPORT gp_Ax1 YAxis() const;
104 //! Reverses the direction of parameterization of <me>.
105 //! The local coordinate system of the conic is modified.
106 Standard_EXPORT void Reverse() Standard_OVERRIDE;
108 //! Returns the parameter on the reversed curve for
109 //! the point of parameter U on <me>.
110 Standard_EXPORT virtual Standard_Real ReversedParameter (const Standard_Real U) const Standard_OVERRIDE = 0;
112 //! The continuity of the conic is Cn.
113 Standard_EXPORT GeomAbs_Shape Continuity() const Standard_OVERRIDE;
117 Standard_EXPORT Standard_Boolean IsCN (const Standard_Integer N) const Standard_OVERRIDE;
119 DEFINE_STANDARD_RTTIEXT(Geom_Conic,Geom_Curve)
125 #endif // _Geom_Conic_HeaderFile