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TKG2d
Geom2d


Geom2d_Circle Class Reference

Describes a circle in the plane (2D space).
A circle is defined by its radius and, as with any conic
curve, is positioned in the plane with a coordinate
system (gp_Ax22d object) where the origin is the
center of the circle.
The coordinate system is the local coordinate
system of the circle.
The orientation (direct or indirect) of the local
coordinate system gives an explicit orientation to the
circle, determining the direction in which the
parameter increases along the circle.
The Geom2d_Circle circle is parameterized by an angle:
P(U) = O + R*Cos(U)*XDir + R*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,
- R is the radius of the circle.
The "X Axis" of the local coordinate system therefore
defines the origin of the parameter of the circle. The
parameter is the angle with this "X Direction".
A circle is a closed and periodic curve. The period is
2.*Pi and the parameter range is [ 0,2.*Pi [.
See Also
GCE2d_MakeCircle which provides functions for
more complex circle constructions
gp_Ax22d and gp_Circ2d for an equivalent, non-parameterized data structure.
.

#include <Geom2d_Circle.hxx>

Inheritance diagram for Geom2d_Circle:

Inheritance graph
[legend]

Public Member Functions

Standard_EXPORT Geom2d_Circle (const gp_Circ2d &C)
 Constructs a circle by conversion of the gp_Circ2d circle C.
.
Standard_EXPORT Geom2d_Circle (const gp_Ax2d &A, const Standard_Real Radius, const Standard_Boolean Sense=Standard_True)
 Constructs a circle of radius Radius, whose center is the origin of axis
A; A is the "X Axis" of the local coordinate system
of the circle; this coordinate system is direct if
Sense is true (default value) or indirect if Sense is false.
Note: It is possible to create a circle where Radius is equal to 0.0.
Exceptions Standard_ConstructionError if Radius is negative.
.
Standard_EXPORT Geom2d_Circle (const gp_Ax22d &A, const Standard_Real Radius)
 Constructs a circle
of radius Radius, where the coordinate system A
locates the circle and defines its orientation in the plane such that:
- the center of the circle is the origin of A,
- the orientation (direct or indirect) of A gives the
orientation of the circle.
.
Standard_EXPORT void SetCirc2d (const gp_Circ2d &C)
 Converts the gp_Circ2d circle C into this circle.
.
Standard_EXPORT void SetRadius (const Standard_Real R)
Standard_EXPORT gp_Circ2d Circ2d () const
 Returns the non persistent circle from gp with the same
geometric properties as <me>.
.
Standard_EXPORT Standard_Real Radius () const
 Returns the radius of this circle.
.
Standard_EXPORT Standard_Real ReversedParameter (const Standard_Real U) const
 Computes the parameter on the reversed circle for
the point of parameter U on this circle.
For a circle, the returned value is: 2.*Pi - U.
.
Standard_EXPORT Standard_Real Eccentricity () const
 Returns 0., which is the eccentricity of any circle.
.
Standard_EXPORT Standard_Real FirstParameter () const
 Returns 0.0
.
Standard_EXPORT Standard_Real LastParameter () const
 Returns 2*PI.
.
Standard_EXPORT Standard_Boolean IsClosed () const
 returns True.

Standard_EXPORT Standard_Boolean IsPeriodic () const
 returns True. The period of a circle is 2.*Pi.

Standard_EXPORT void D0 (const Standard_Real U, gp_Pnt2d &P) const
 Returns in P the point of parameter U.
P = C + R * Cos (U) * XDir + R * Sin (U) * YDir
where C is the center of the circle , XDir the XDirection and
YDir the YDirection of the circle's local coordinate system.
.
Standard_EXPORT void D1 (const Standard_Real U, gp_Pnt2d &P, gp_Vec2d &V1) const
 Returns the point P of parameter U and the first derivative V1.
.
Standard_EXPORT void D2 (const Standard_Real U, gp_Pnt2d &P, gp_Vec2d &V1, gp_Vec2d &V2) const
 Returns the point P of parameter U, the first and second
derivatives V1 and V2.
.
Standard_EXPORT void D3 (const Standard_Real U, gp_Pnt2d &P, gp_Vec2d &V1, gp_Vec2d &V2, gp_Vec2d &V3) const
 Returns the point P of parameter u, the first second and third
derivatives V1 V2 and V3.
.
Standard_EXPORT gp_Vec2d DN (const Standard_Real U, const Standard_Integer N) const
 For the point of parameter U of this circle, computes
the vector corresponding to the Nth derivative.
Exceptions: Standard_RangeError if N is less than 1.
.
Standard_EXPORT void Transform (const gp_Trsf2d &T)
 Applies the transformation T to this circle.
.
Standard_EXPORT Handle_Geom2d_Geometry Copy () const
 Creates a new object which is a copy of this circle.
.
Standard_EXPORT const Handle (Standard_Type)&DynamicType() const

Private Attributes

Standard_Real radius

Constructor & Destructor Documentation

Standard_EXPORT Geom2d_Circle::Geom2d_Circle const gp_Circ2d &  C  ) 
 

Standard_EXPORT Geom2d_Circle::Geom2d_Circle const gp_Ax2d &  A,
const Standard_Real  Radius,
const Standard_Boolean  Sense = Standard_True
 

Standard_EXPORT Geom2d_Circle::Geom2d_Circle const gp_Ax22d &  A,
const Standard_Real  Radius
 


Member Function Documentation

Standard_EXPORT gp_Circ2d Geom2d_Circle::Circ2d  )  const
 

Standard_EXPORT Handle_Geom2d_Geometry Geom2d_Circle::Copy  )  const [virtual]
 

Implements Geom2d_Geometry.

Standard_EXPORT void Geom2d_Circle::D0 const Standard_Real  U,
gp_Pnt2d &  P
const [virtual]
 

Implements Geom2d_Curve.

Standard_EXPORT void Geom2d_Circle::D1 const Standard_Real  U,
gp_Pnt2d &  P,
gp_Vec2d &  V1
const [virtual]
 

Implements Geom2d_Curve.

Standard_EXPORT void Geom2d_Circle::D2 const Standard_Real  U,
gp_Pnt2d &  P,
gp_Vec2d &  V1,
gp_Vec2d &  V2
const [virtual]
 

Implements Geom2d_Curve.

Standard_EXPORT void Geom2d_Circle::D3 const Standard_Real  U,
gp_Pnt2d &  P,
gp_Vec2d &  V1,
gp_Vec2d &  V2,
gp_Vec2d &  V3
const [virtual]
 

Implements Geom2d_Curve.

Standard_EXPORT gp_Vec2d Geom2d_Circle::DN const Standard_Real  U,
const Standard_Integer  N
const [virtual]
 

Implements Geom2d_Curve.

Standard_EXPORT Standard_Real Geom2d_Circle::Eccentricity  )  const [virtual]
 

Implements Geom2d_Conic.

Standard_EXPORT Standard_Real Geom2d_Circle::FirstParameter  )  const [virtual]
 

Implements Geom2d_Curve.

Standard_EXPORT const Geom2d_Circle::Handle Standard_Type   )  const
 

Reimplemented from Geom2d_Conic.

Standard_EXPORT Standard_Boolean Geom2d_Circle::IsClosed  )  const [virtual]
 

Implements Geom2d_Curve.

Standard_EXPORT Standard_Boolean Geom2d_Circle::IsPeriodic  )  const [virtual]
 

Implements Geom2d_Curve.

Standard_EXPORT Standard_Real Geom2d_Circle::LastParameter  )  const [virtual]
 

Implements Geom2d_Curve.

Standard_EXPORT Standard_Real Geom2d_Circle::Radius  )  const
 

Standard_EXPORT Standard_Real Geom2d_Circle::ReversedParameter const Standard_Real  U  )  const [virtual]
 

Implements Geom2d_Conic.

Standard_EXPORT void Geom2d_Circle::SetCirc2d const gp_Circ2d &  C  ) 
 

Standard_EXPORT void Geom2d_Circle::SetRadius const Standard_Real  R  ) 
 

Standard_EXPORT void Geom2d_Circle::Transform const gp_Trsf2d &  T  )  [virtual]
 

Implements Geom2d_Geometry.


Field Documentation

Standard_Real Geom2d_Circle::radius [private]
 


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