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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_Ellipse_HeaderFile 0018 #define _Geom2d_Ellipse_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_Elips2d; 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_Ellipse; 0035 DEFINE_STANDARD_HANDLE(Geom2d_Ellipse, Geom2d_Conic) 0036 0037 //! Describes an ellipse in the plane (2D space). 0038 //! An ellipse is defined by its major and minor radii and, 0039 //! as with any conic curve, is positioned in the plane 0040 //! with a coordinate system (gp_Ax22d object) where: 0041 //! - the origin is the center of the ellipse, 0042 //! - the "X Direction" defines the major axis, and 0043 //! - the "Y Direction" defines the minor axis. 0044 //! This coordinate system is the local coordinate system of the ellipse. 0045 //! The orientation (direct or indirect) of the local 0046 //! coordinate system gives an explicit orientation to the 0047 //! ellipse, determining the direction in which the 0048 //! parameter increases along the ellipse. 0049 //! The Geom2d_Ellipse ellipse is parameterized by an angle: 0050 //! P(U) = O + MajorRad*Cos(U)*XDir + MinorRad*Sin(U)*YDir 0051 //! where: 0052 //! - P is the point of parameter U, 0053 //! - O, XDir and YDir are respectively the origin, "X 0054 //! Direction" and "Y Direction" of its local coordinate system, 0055 //! - MajorRad and MinorRad are the major and 0056 //! minor radii of the ellipse. 0057 //! The "X Axis" of the local coordinate system therefore 0058 //! defines the origin of the parameter of the ellipse. 0059 //! An ellipse is a closed and periodic curve. The period 0060 //! is 2.*Pi and the parameter range is [ 0,2.*Pi [. 0061 //! See Also 0062 //! GCE2d_MakeEllipse which provides functions for 0063 //! more complex ellipse constructions 0064 //! gp_Ax22d 0065 //! gp_Elips2d for an equivalent, non-parameterized data structure 0066 class Geom2d_Ellipse : public Geom2d_Conic 0067 { 0068 0069 public: 0070 0071 0072 0073 //! Creates an ellipse by conversion of the gp_Elips2d ellipse E. 0074 Standard_EXPORT Geom2d_Ellipse(const gp_Elips2d& E); 0075 0076 //! Creates an ellipse defined by its major and minor radii, 0077 //! MajorRadius and MinorRadius, and positioned 0078 //! in the plane by its major axis MajorAxis; the 0079 //! center of the ellipse is the origin of MajorAxis 0080 //! and the unit vector of MajorAxis is the "X 0081 //! Direction" of the local coordinate system of the 0082 //! ellipse; this coordinate system is direct if Sense 0083 //! is true (default value) or indirect if Sense is false. 0084 //! Warnings : 0085 //! It is not forbidden to create an ellipse with MajorRadius = 0086 //! MinorRadius. 0087 //! Exceptions 0088 //! Standard_ConstructionError if: 0089 //! - MajorRadius is less than MinorRadius, or 0090 //! - MinorRadius is less than 0. 0091 Standard_EXPORT Geom2d_Ellipse(const gp_Ax2d& MajorAxis, const Standard_Real MajorRadius, const Standard_Real MinorRadius, const Standard_Boolean Sense = Standard_True); 0092 0093 //! Creates an ellipse defined by its major and minor radii, 0094 //! MajorRadius and MinorRadius, where the 0095 //! coordinate system Axis locates the ellipse and 0096 //! defines its orientation in the plane such that: 0097 //! - the center of the ellipse is the origin of Axis, 0098 //! - the "X Direction" of Axis defines the major 0099 //! axis of the ellipse, 0100 //! - the "Y Direction" of Axis defines the minor 0101 //! axis of the ellipse, 0102 //! - the orientation of Axis (direct or indirect) 0103 //! gives the orientation of the ellipse. 0104 //! Warnings : 0105 //! It is not forbidden to create an ellipse with MajorRadius = 0106 //! MinorRadius. 0107 //! Exceptions 0108 //! Standard_ConstructionError if: 0109 //! - MajorRadius is less than MinorRadius, or 0110 //! - MinorRadius is less than 0. 0111 Standard_EXPORT Geom2d_Ellipse(const gp_Ax22d& Axis, const Standard_Real MajorRadius, const Standard_Real MinorRadius); 0112 0113 //! Converts the gp_Elips2d ellipse E into this ellipse. 0114 Standard_EXPORT void SetElips2d (const gp_Elips2d& E); 0115 0116 //! Assigns a value to the major radius of this ellipse. 0117 //! Exceptions 0118 //! Standard_ConstructionError if: 0119 //! - the major radius of this ellipse becomes less than 0120 //! the minor radius, or 0121 //! - MinorRadius is less than 0. 0122 Standard_EXPORT void SetMajorRadius (const Standard_Real MajorRadius); 0123 0124 //! Assigns a value to the minor radius of this ellipse. 0125 //! Exceptions 0126 //! Standard_ConstructionError if: 0127 //! - the major radius of this ellipse becomes less than 0128 //! the minor radius, or 0129 //! - MinorRadius is less than 0. 0130 Standard_EXPORT void SetMinorRadius (const Standard_Real MinorRadius); 0131 0132 //! Converts this ellipse into a gp_Elips2d ellipse. 0133 Standard_EXPORT gp_Elips2d Elips2d() const; 0134 0135 //! Computes the parameter on the reversed ellipse for 0136 //! the point of parameter U on this ellipse. 0137 //! For an ellipse, the returned value is: 2.*Pi - U. 0138 Standard_EXPORT Standard_Real ReversedParameter (const Standard_Real U) const Standard_OVERRIDE; 0139 0140 //! Computes the directrices of this ellipse. 0141 //! This directrix is the line normal to the XAxis of the ellipse 0142 //! in the local plane (Z = 0) at a distance d = MajorRadius / e 0143 //! from the center of the ellipse, where e is the eccentricity of 0144 //! the ellipse. 0145 //! This line is parallel to the "YAxis". The intersection point 0146 //! between directrix1 and the "XAxis" is the "Location" point 0147 //! of the directrix1. This point is on the positive side of 0148 //! the "XAxis". 0149 //! Raises ConstructionError if Eccentricity = 0.0. (The ellipse degenerates 0150 //! into a circle) 0151 Standard_EXPORT gp_Ax2d Directrix1() const; 0152 0153 0154 //! This line is obtained by the symmetrical transformation 0155 //! of "Directrix1" with respect to the "YAxis" of the ellipse. 0156 //! Raises ConstructionError if Eccentricity = 0.0. (The ellipse degenerates into a 0157 //! circle). 0158 Standard_EXPORT gp_Ax2d Directrix2() const; 0159 0160 0161 //! Returns the eccentricity of the ellipse between 0.0 and 1.0 0162 //! If f is the distance between the center of the ellipse and 0163 //! the Focus1 then the eccentricity e = f / MajorRadius. 0164 //! Returns 0 if MajorRadius = 0 0165 Standard_EXPORT Standard_Real Eccentricity() const Standard_OVERRIDE; 0166 0167 0168 //! Computes the focal distance. The focal distance is the distance between the center 0169 //! and a focus of the ellipse. 0170 Standard_EXPORT Standard_Real Focal() const; 0171 0172 0173 //! Returns the first focus of the ellipse. This focus is on the 0174 //! positive side of the "XAxis" of the ellipse. 0175 Standard_EXPORT gp_Pnt2d Focus1() const; 0176 0177 0178 //! Returns the second focus of the ellipse. This focus is on 0179 //! the negative side of the "XAxis" of the ellipse. 0180 Standard_EXPORT gp_Pnt2d Focus2() const; 0181 0182 //! Returns the major radius of this ellipse. 0183 Standard_EXPORT Standard_Real MajorRadius() const; 0184 0185 //! Returns the minor radius of this ellipse. 0186 Standard_EXPORT Standard_Real MinorRadius() const; 0187 0188 0189 //! Computes the parameter of this ellipse. This value is 0190 //! given by the formula p = (1 - e * e) * MajorRadius where e is the eccentricity 0191 //! of the ellipse. 0192 //! Returns 0 if MajorRadius = 0 0193 Standard_EXPORT Standard_Real Parameter() const; 0194 0195 //! Returns the value of the first parameter of this 0196 //! ellipse. This is 0.0, which gives the start point of this ellipse. 0197 //! The start point and end point of an ellipse are coincident. 0198 Standard_EXPORT Standard_Real FirstParameter() const Standard_OVERRIDE; 0199 0200 //! Returns the value of the last parameter of this 0201 //! ellipse. This is 2.*Pi, which gives the end point of this ellipse. 0202 //! The start point and end point of an ellipse are coincident. 0203 Standard_EXPORT Standard_Real LastParameter() const Standard_OVERRIDE; 0204 0205 //! return True. 0206 Standard_EXPORT Standard_Boolean IsClosed() const Standard_OVERRIDE; 0207 0208 //! return True. 0209 Standard_EXPORT Standard_Boolean IsPeriodic() const Standard_OVERRIDE; 0210 0211 //! Returns in P the point of parameter U. 0212 //! P = C + MajorRadius * Cos (U) * XDir + MinorRadius * Sin (U) * YDir 0213 //! where C is the center of the ellipse , XDir the direction of 0214 //! the "XAxis" and "YDir" the "YAxis" of the ellipse. 0215 Standard_EXPORT void D0 (const Standard_Real U, gp_Pnt2d& P) const Standard_OVERRIDE; 0216 0217 Standard_EXPORT void D1 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1) const Standard_OVERRIDE; 0218 0219 0220 //! Returns the point P of parameter U. The vectors V1 and V2 0221 //! are the first and second derivatives at this point. 0222 Standard_EXPORT void D2 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1, gp_Vec2d& V2) const Standard_OVERRIDE; 0223 0224 0225 //! Returns the point P of parameter U, the first second and 0226 //! third derivatives V1 V2 and V3. 0227 Standard_EXPORT void D3 (const Standard_Real U, gp_Pnt2d& P, gp_Vec2d& V1, gp_Vec2d& V2, gp_Vec2d& V3) const Standard_OVERRIDE; 0228 0229 //! For the point of parameter U of this ellipse, 0230 //! computes the vector corresponding to the Nth derivative. 0231 //! Exceptions Standard_RangeError if N is less than 1. 0232 Standard_EXPORT gp_Vec2d DN (const Standard_Real U, const Standard_Integer N) const Standard_OVERRIDE; 0233 0234 //! Applies the transformation T to this ellipse. 0235 Standard_EXPORT void Transform (const gp_Trsf2d& T) Standard_OVERRIDE; 0236 0237 //! Creates a new object which is a copy of this ellipse. 0238 Standard_EXPORT Handle(Geom2d_Geometry) Copy() const Standard_OVERRIDE; 0239 0240 //! Dumps the content of me into the stream 0241 Standard_EXPORT virtual void DumpJson (Standard_OStream& theOStream, Standard_Integer theDepth = -1) const Standard_OVERRIDE; 0242 0243 0244 0245 0246 DEFINE_STANDARD_RTTIEXT(Geom2d_Ellipse,Geom2d_Conic) 0247 0248 protected: 0249 0250 0251 0252 0253 private: 0254 0255 0256 Standard_Real majorRadius; 0257 Standard_Real minorRadius; 0258 0259 0260 }; 0261 0262 0263 0264 0265 0266 0267 0268 #endif // _Geom2d_Ellipse_HeaderFile
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