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0001 // Created on: 1993-03-24 0002 // Created by: JCV 0003 // Copyright (c) 1993-1999 Matra Datavision 0004 // Copyright (c) 1999-2014 OPEN CASCADE SAS 0005 // 0006 // This file is part of Open CASCADE Technology software library. 0007 // 0008 // This library is free software; you can redistribute it and/or modify it under 0009 // the terms of the GNU Lesser General Public License version 2.1 as published 0010 // by the Free Software Foundation, with special exception defined in the file 0011 // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT 0012 // distribution for complete text of the license and disclaimer of any warranty. 0013 // 0014 // Alternatively, this file may be used under the terms of Open CASCADE 0015 // commercial license or contractual agreement. 0016 0017 #ifndef _Geom2d_Parabola_HeaderFile 0018 #define _Geom2d_Parabola_HeaderFile 0019 0020 #include <Standard.hxx> 0021 #include <Standard_Type.hxx> 0022 0023 #include <Geom2d_Conic.hxx> 0024 #include <Standard_Integer.hxx> 0025 class gp_Parab2d; 0026 class gp_Ax2d; 0027 class gp_Ax22d; 0028 class gp_Pnt2d; 0029 class gp_Vec2d; 0030 class gp_Trsf2d; 0031 class Geom2d_Geometry; 0032 0033 0034 class Geom2d_Parabola; 0035 DEFINE_STANDARD_HANDLE(Geom2d_Parabola, Geom2d_Conic) 0036 0037 //! Describes a parabola in the plane (2D space). 0038 //! A parabola is defined by its focal length (i.e. the 0039 //! distance between its focus and its apex) and is 0040 //! positioned in the plane with a coordinate system 0041 //! (gp_Ax22d object) where: 0042 //! - the origin is the apex of the parabola, and 0043 //! - the "X Axis" defines the axis of symmetry; the 0044 //! parabola is on the positive side of this axis. 0045 //! This coordinate system is the local coordinate 0046 //! system of the parabola. 0047 //! The orientation (direct or indirect) of the local 0048 //! coordinate system gives an explicit orientation to the 0049 //! parabola, determining the direction in which the 0050 //! parameter increases along the parabola. 0051 //! The Geom_Parabola parabola is parameterized as follows: 0052 //! P(U) = O + U*U/(4.*F)*XDir + U*YDir, where: 0053 //! - P is the point of parameter U, 0054 //! - O, XDir and YDir are respectively the origin, "X 0055 //! Direction" and "Y Direction" of its local coordinate system, 0056 //! - F is the focal length of the parabola. 0057 //! The parameter of the parabola is therefore its Y 0058 //! coordinate in the local coordinate system, with the "X 0059 //! Axis" of the local coordinate system defining the 0060 //! origin of the parameter. 0061 //! The parameter range is ] -infinite,+infinite [. 0062 class Geom2d_Parabola : public Geom2d_Conic 0063 { 0064 0065 public: 0066 0067 0068 //! Creates a parabola from a non persistent one. 0069 Standard_EXPORT Geom2d_Parabola(const gp_Parab2d& Prb); 0070 0071 0072 //! Creates a parabola with its "MirrorAxis" and it's focal 0073 //! length "Focal". 0074 //! MirrorAxis is the axis of symmetry of the curve, it is the 0075 //! "XAxis". The "YAxis" is parallel to the directrix of the 0076 //! parabola and is in the direct sense if Sense is True. 0077 //! The "Location" point of "MirrorAxis" is the vertex of the parabola 0078 //! Raised if Focal < 0.0 0079 Standard_EXPORT Geom2d_Parabola(const gp_Ax2d& MirrorAxis, const Standard_Real Focal, const Standard_Boolean Sense = Standard_True); 0080 0081 0082 //! Creates a parabola with its Axis and it's focal 0083 //! length "Focal". 0084 //! The XDirection of Axis is the axis of symmetry of the curve, 0085 //! it is the "XAxis". The "YAxis" is parallel to the directrix of the 0086 //! parabola. The "Location" point of "Axis" is the vertex 0087 //! of the parabola. 0088 //! Raised if Focal < 0.0 0089 Standard_EXPORT Geom2d_Parabola(const gp_Ax22d& Axis, const Standard_Real Focal); 0090 0091 0092 //! D is the directrix of the parabola and F the focus point. 0093 //! The symmetry axis "XAxis" of the parabola is normal to the 0094 //! directrix and pass through the focus point F, but its 0095 //! "Location" point is the vertex of the parabola. 0096 //! The "YAxis" of the parabola is parallel to D and its "Location" 0097 //! point is the vertex of the parabola. 0098 Standard_EXPORT Geom2d_Parabola(const gp_Ax2d& D, const gp_Pnt2d& F); 0099 0100 //! Assigns the value Focal to the focal length of this parabola. 0101 //! Exceptions Standard_ConstructionError if Focal is negative. 0102 Standard_EXPORT void SetFocal (const Standard_Real Focal); 0103 0104 //! Converts the gp_Parab2d parabola Prb into this parabola. 0105 Standard_EXPORT void SetParab2d (const gp_Parab2d& Prb); 0106 0107 0108 //! Returns the non persistent parabola from gp with the same 0109 //! geometric properties as <me>. 0110 Standard_EXPORT gp_Parab2d Parab2d() const; 0111 0112 //! Computes the parameter on the reversed parabola 0113 //! for the point of parameter U on this parabola. 0114 //! For a parabola, the returned value is -U. 0115 Standard_EXPORT Standard_Real ReversedParameter (const Standard_Real U) const Standard_OVERRIDE; 0116 0117 //! Returns RealFirst from Standard. 0118 Standard_EXPORT Standard_Real FirstParameter() const Standard_OVERRIDE; 0119 0120 //! Returns RealLast from Standard. 0121 Standard_EXPORT Standard_Real LastParameter() const Standard_OVERRIDE; 0122 0123 //! Returns False 0124 Standard_EXPORT Standard_Boolean IsClosed() const Standard_OVERRIDE; 0125 0126 //! Returns False 0127 Standard_EXPORT Standard_Boolean IsPeriodic() const Standard_OVERRIDE; 0128 0129 //! The directrix is parallel to the "YAxis" of the parabola. 0130 //! The "Location" point of the directrix is the intersection 0131 //! point between the directrix and the symmetry axis ("XAxis") of the parabola. 0132 Standard_EXPORT gp_Ax2d Directrix() const; 0133 0134 //! Returns the eccentricity e = 1.0 0135 Standard_EXPORT Standard_Real Eccentricity() const Standard_OVERRIDE; 0136 0137 //! Computes the focus of this parabola The focus is on the 0138 //! positive side of the "X Axis" of the local coordinate system of the parabola. 0139 Standard_EXPORT gp_Pnt2d Focus() const; 0140 0141 //! Computes the focal length of this parabola. 0142 //! The focal length is the distance between the apex and the focus of the parabola. 0143 Standard_EXPORT Standard_Real Focal() const; 0144 0145 //! Computes the parameter of this parabola, which is 0146 //! the distance between its focus and its directrix. This 0147 //! distance is twice the focal length. 0148 //! If P is the parameter of the parabola, the equation of 0149 //! the parabola in its local coordinate system is: Y**2 = 2.*P*X. 0150 Standard_EXPORT Standard_Real Parameter() const; 0151 0152 //! Returns in P the point of parameter U. 0153 //! If U = 0 the returned point is the origin of the XAxis and 0154 //! the YAxis of the parabola and it is the vertex of the parabola. 0155 //! P = S + F * (U * U * XDir + * U * YDir) 0156 //! where S is the vertex of the parabola, XDir the XDirection and 0157 //! YDir the YDirection of the parabola's local coordinate system. 0158 Standard_EXPORT void D0 (const Standard_Real U, gp_Pnt2d& P) const Standard_OVERRIDE; 0159 0160 0161 //! Returns the point P of parameter U and the first derivative V1. 0162 Standard_EXPORT void D1 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1) const Standard_OVERRIDE; 0163 0164 0165 //! Returns the point P of parameter U, the first and second 0166 //! derivatives V1 and V2. 0167 Standard_EXPORT void D2 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1, gp_Vec2d& V2) const Standard_OVERRIDE; 0168 0169 0170 //! Returns the point P of parameter U, the first second and third 0171 //! derivatives V1 V2 and V3. 0172 Standard_EXPORT void D3 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1, gp_Vec2d& V2, gp_Vec2d& V3) const Standard_OVERRIDE; 0173 0174 //! For the point of parameter U of this parabola, 0175 //! computes the vector corresponding to the Nth derivative. 0176 //! Exceptions Standard_RangeError if N is less than 1. 0177 Standard_EXPORT gp_Vec2d DN (const Standard_Real U, const Standard_Integer N) const Standard_OVERRIDE; 0178 0179 //! Applies the transformation T to this parabola. 0180 Standard_EXPORT void Transform (const gp_Trsf2d& T) Standard_OVERRIDE; 0181 0182 //! Computes the parameter on the transformed 0183 //! parabola, for the point of parameter U on this parabola. 0184 //! For a parabola, the returned value is equal to U 0185 //! multiplied by the scale factor of transformation T. 0186 Standard_EXPORT Standard_Real TransformedParameter (const Standard_Real U, const gp_Trsf2d& T) const Standard_OVERRIDE; 0187 0188 //! Returns a coefficient to compute the parameter on 0189 //! the transformed curve for the transform of the 0190 //! point on <me>. 0191 //! 0192 //! Transformed(T)->Value(U * ParametricTransformation(T)) 0193 //! 0194 //! is the same point as 0195 //! 0196 //! Value(U).Transformed(T) 0197 //! 0198 //! This methods returns T.ScaleFactor() 0199 Standard_EXPORT Standard_Real ParametricTransformation (const gp_Trsf2d& T) const Standard_OVERRIDE; 0200 0201 //! Creates a new object, which is a copy of this parabola. 0202 Standard_EXPORT Handle(Geom2d_Geometry) Copy() const Standard_OVERRIDE; 0203 0204 //! Dumps the content of me into the stream 0205 Standard_EXPORT virtual void DumpJson (Standard_OStream& theOStream, Standard_Integer theDepth = -1) const Standard_OVERRIDE; 0206 0207 0208 0209 0210 DEFINE_STANDARD_RTTIEXT(Geom2d_Parabola,Geom2d_Conic) 0211 0212 protected: 0213 0214 0215 0216 0217 private: 0218 0219 0220 Standard_Real focalLength; 0221 0222 0223 }; 0224 0225 0226 0227 0228 0229 0230 0231 #endif // _Geom2d_Parabola_HeaderFile
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