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TKG3d
Geom


Geom_Ellipse Class Reference

Describes an ellipse in 3D space.
An ellipse is defined by its major and minor radii and,
as with any conic curve, is positioned in space with a
right-handed coordinate system (gp_Ax2 object) where:
- the origin is the center of the ellipse,
- the "X Direction" defines the major axis, and
- the "Y Direction" defines the minor axis.
The origin, "X Direction" and "Y Direction" of this
coordinate system define the plane of the ellipse. The
coordinate system is the local coordinate system of the ellipse.
The "main Direction" of this coordinate system is the
vector normal to the plane of the ellipse. The axis, of
which the origin and unit vector are respectively the
origin and "main Direction" of the local coordinate
system, is termed the "Axis" or "main Axis" of the ellipse.
The "main Direction" of the local coordinate system
gives an explicit orientation to the ellipse (definition of
the trigonometric sense), determining the direction in
which the parameter increases along the ellipse.
The Geom_Ellipse ellipse is parameterized by an angle:
P(U) = O + MajorRad*Cos(U)*XDir + MinorRad*Sin(U)*YDir
where:
- P is the point of parameter U,
- O, XDir and YDir are respectively the origin, "X <br> Direction" and "Y Direction" of its local coordinate system,
- MajorRad and MinorRad are the major and minor radii of the ellipse.
The "X Axis" of the local coordinate system therefore
defines the origin of the parameter of the ellipse.
An ellipse is a closed and periodic curve. The period
is 2.*Pi and the parameter range is [ 0, 2.*Pi [.
.

#include <Geom_Ellipse.hxx>

Inheritance diagram for Geom_Ellipse:

Inheritance graph
[legend]

Public Member Functions

Standard_EXPORT Geom_Ellipse (const gp_Elips &E)
 Constructs an ellipse by conversion of the gp_Elips ellipse E.
.
Standard_EXPORT Geom_Ellipse (const gp_Ax2 &A2, const Standard_Real MajorRadius, const Standard_Real MinorRadius)
 Constructs an ellipse
defined by its major and minor radii, MajorRadius
and MinorRadius, where A2 locates the ellipse
and defines its orientation in 3D space such that:
- the center of the ellipse is the origin of A2,
- the "X Direction" of A2 defines the major axis
of the ellipse, i.e. the major radius
MajorRadius is measured along this axis,
- the "Y Direction" of A2 defines the minor axis
of the ellipse, i.e. the minor radius
MinorRadius is measured along this axis,
- A2 is the local coordinate system of the ellipse.
Exceptions
Standard_ConstructionError if:
- MajorRadius is less than MinorRadius, or
- MinorRadius is less than 0.
Warning The Geom package does not prevent the
construction of an ellipse where MajorRadius and
MinorRadius are equal.
.
Standard_EXPORT void SetElips (const gp_Elips &E)
 Converts the gp_Elips ellipse E into this ellipse.
.
Standard_EXPORT void SetMajorRadius (const Standard_Real MajorRadius)
 Assigns a value to the major radius of this ellipse.
ConstructionError raised if MajorRadius < MinorRadius.
.
Standard_EXPORT void SetMinorRadius (const Standard_Real MinorRadius)
 Assigns a value to the minor radius of this ellipse.
ConstructionError raised if MajorRadius < MinorRadius or if MinorRadius < 0.
.
Standard_EXPORT gp_Elips Elips () const
 returns the non transient ellipse from gp with the same

Standard_EXPORT Standard_Real ReversedParameter (const Standard_Real U) const
 Computes the parameter on the reversed ellipse for
the point of parameter U on this ellipse.
For an ellipse, the returned value is: 2.*Pi - U.
.
Standard_EXPORT gp_Ax1 Directrix1 () const
 This directrix is the line normal to the XAxis of the ellipse
in the local plane (Z = 0) at a distance d = MajorRadius / e
from the center of the ellipse, where e is the eccentricity of
the ellipse.
This line is parallel to the "YAxis". The intersection point
between directrix1 and the "XAxis" is the "Location" point
of the directrix1. This point is on the positive side of
the "XAxis".
//! Raised if Eccentricity = 0.0. (The ellipse degenerates
into a circle)
.
Standard_EXPORT gp_Ax1 Directrix2 () const
 This line is obtained by the symmetrical transformation
of "Directrix1" with respect to the "YAxis" of the ellipse.
Raised if Eccentricity = 0.0. (The ellipse degenerates into a
circle).
.
Standard_EXPORT Standard_Real Eccentricity () const
 Returns the eccentricity of the ellipse between 0.0 and 1.0
If f is the distance between the center of the ellipse and
the Focus1 then the eccentricity e = f / MajorRadius.
Returns 0 if MajorRadius = 0
.
Standard_EXPORT Standard_Real Focal () const
 Computes the focal distance. It is the distance between the
the two focus of the ellipse.
.
Standard_EXPORT gp_Pnt Focus1 () const
 Returns the first focus of the ellipse. This focus is on the
positive side of the "XAxis" of the ellipse.
.
Standard_EXPORT gp_Pnt Focus2 () const
 Returns the second focus of the ellipse. This focus is on
the negative side of the "XAxis" of the ellipse.
.
Standard_EXPORT Standard_Real MajorRadius () const
 Returns the major radius of this ellipse.
.
Standard_EXPORT Standard_Real MinorRadius () const
 Returns the minor radius of this ellipse.
.
Standard_EXPORT Standard_Real Parameter () const
 Returns p = (1 - e * e) * MajorRadius where e is the eccentricity
of the ellipse.
Returns 0 if MajorRadius = 0
.
Standard_EXPORT Standard_Real FirstParameter () const
 Returns the value of the first parameter of this
ellipse. This is respectively:
- 0.0, which gives the start point of this ellipse, or
The start point and end point of an ellipse are coincident.
.
Standard_EXPORT Standard_Real LastParameter () const
 Returns the value of the last parameter of this
ellipse. This is respectively:
- 2.*Pi, which gives the end point of this ellipse.
The start point and end point of an ellipse are coincident.
.
Standard_EXPORT Standard_Boolean IsClosed () const
 return True.

Standard_EXPORT Standard_Boolean IsPeriodic () const
 return True.

Standard_EXPORT void D0 (const Standard_Real U, gp_Pnt &P) const
 Returns in P the point of parameter U.
P = C + MajorRadius * Cos (U) * XDir + MinorRadius * Sin (U) * YDir
where C is the center of the ellipse , XDir the direction of
the "XAxis" and "YDir" the "YAxis" of the ellipse.
.
Standard_EXPORT void D1 (const Standard_Real U, gp_Pnt &P, gp_Vec &V1) const
 Returns the point P of parameter U and the first derivative V1.
//! Raised if the continuity of the curve is not C1.
.
Standard_EXPORT void D2 (const Standard_Real U, gp_Pnt &P, gp_Vec &V1, gp_Vec &V2) const
 Returns the point P of parameter U. The vectors V1 and V2
are the first and second derivatives at this point.
.
Standard_EXPORT void D3 (const Standard_Real U, gp_Pnt &P, gp_Vec &V1, gp_Vec &V2, gp_Vec &V3) const
 Returns the point P of parameter U, the first second and
third derivatives V1 V2 and V3.
.
Standard_EXPORT gp_Vec DN (const Standard_Real U, const Standard_Integer N) const
 For the point of parameter U of this ellipse, computes
the vector corresponding to the Nth derivative.
Exceptions Standard_RangeError if N is less than 1.
.
Standard_EXPORT void Transform (const gp_Trsf &T)
 Applies the transformation T to this ellipse.
.
Standard_EXPORT Handle_Geom_Geometry Copy () const
 Creates a new object which is a copy of this ellipse.
.
Standard_EXPORT const Handle (Standard_Type)&DynamicType() const

Private Attributes

Standard_Real majorRadius
Standard_Real minorRadius

Constructor & Destructor Documentation

Standard_EXPORT Geom_Ellipse::Geom_Ellipse const gp_Elips &  E  ) 
 

Standard_EXPORT Geom_Ellipse::Geom_Ellipse const gp_Ax2 &  A2,
const Standard_Real  MajorRadius,
const Standard_Real  MinorRadius
 


Member Function Documentation

Standard_EXPORT Handle_Geom_Geometry Geom_Ellipse::Copy  )  const [virtual]
 

Implements Geom_Geometry.

Standard_EXPORT void Geom_Ellipse::D0 const Standard_Real  U,
gp_Pnt &  P
const [virtual]
 

Implements Geom_Curve.

Standard_EXPORT void Geom_Ellipse::D1 const Standard_Real  U,
gp_Pnt &  P,
gp_Vec &  V1
const [virtual]
 

Implements Geom_Curve.

Standard_EXPORT void Geom_Ellipse::D2 const Standard_Real  U,
gp_Pnt &  P,
gp_Vec &  V1,
gp_Vec &  V2
const [virtual]
 

Implements Geom_Curve.

Standard_EXPORT void Geom_Ellipse::D3 const Standard_Real  U,
gp_Pnt &  P,
gp_Vec &  V1,
gp_Vec &  V2,
gp_Vec &  V3
const [virtual]
 

Implements Geom_Curve.

Standard_EXPORT gp_Ax1 Geom_Ellipse::Directrix1  )  const
 

Standard_EXPORT gp_Ax1 Geom_Ellipse::Directrix2  )  const
 

Standard_EXPORT gp_Vec Geom_Ellipse::DN const Standard_Real  U,
const Standard_Integer  N
const [virtual]
 

Implements Geom_Curve.

Standard_EXPORT Standard_Real Geom_Ellipse::Eccentricity  )  const [virtual]
 

Implements Geom_Conic.

Standard_EXPORT gp_Elips Geom_Ellipse::Elips  )  const
 

Standard_EXPORT Standard_Real Geom_Ellipse::FirstParameter  )  const [virtual]
 

Implements Geom_Curve.

Standard_EXPORT Standard_Real Geom_Ellipse::Focal  )  const
 

Standard_EXPORT gp_Pnt Geom_Ellipse::Focus1  )  const
 

Standard_EXPORT gp_Pnt Geom_Ellipse::Focus2  )  const
 

Standard_EXPORT const Geom_Ellipse::Handle Standard_Type   )  const
 

Reimplemented from Geom_Conic.

Standard_EXPORT Standard_Boolean Geom_Ellipse::IsClosed  )  const [virtual]
 

Implements Geom_Curve.

Standard_EXPORT Standard_Boolean Geom_Ellipse::IsPeriodic  )  const [virtual]
 

Implements Geom_Curve.

Standard_EXPORT Standard_Real Geom_Ellipse::LastParameter  )  const [virtual]
 

Implements Geom_Curve.

Standard_EXPORT Standard_Real Geom_Ellipse::MajorRadius  )  const
 

Standard_EXPORT Standard_Real Geom_Ellipse::MinorRadius  )  const
 

Standard_EXPORT Standard_Real Geom_Ellipse::Parameter  )  const
 

Standard_EXPORT Standard_Real Geom_Ellipse::ReversedParameter const Standard_Real  U  )  const [virtual]
 

Implements Geom_Conic.

Standard_EXPORT void Geom_Ellipse::SetElips const gp_Elips &  E  ) 
 

Standard_EXPORT void Geom_Ellipse::SetMajorRadius const Standard_Real  MajorRadius  ) 
 

Standard_EXPORT void Geom_Ellipse::SetMinorRadius const Standard_Real  MinorRadius  ) 
 

Standard_EXPORT void Geom_Ellipse::Transform const gp_Trsf &  T  )  [virtual]
 

Implements Geom_Geometry.


Field Documentation

Standard_Real Geom_Ellipse::majorRadius [private]
 

Standard_Real Geom_Ellipse::minorRadius [private]
 


The documentation for this class was generated from the following file:
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