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Public Member Functions
gp_Parab2d Class Reference

Describes a parabola in the plane (2D space).
A parabola is defined by its focal length (that is, the
distance between its focus and apex) and positioned in
the plane with a coordinate system (a gp_Ax22d object) where:
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#include <gp_Parab2d.hxx>

Public Member Functions

DEFINE_STANDARD_ALLOC gp_Parab2d ()
 Creates an indefinite parabola.

 gp_Parab2d (const gp_Ax2d &MirrorAxis, const Standard_Real Focal, const Standard_Boolean Sense=Standard_True)
 Creates a parabola with its vertex point, its axis of symmetry
("XAxis") and its focal length.
The sense of parametrization is given by Sense.
Warnings : It is possible to have Focal = 0.
Raises ConstructionError if Focal < 0.0

 gp_Parab2d (const gp_Ax22d &A, const Standard_Real Focal)
 Creates a parabola with its vertex point, its axis of symmetry
("XAxis") and its focal length.
The sense of parametrization is given by A.
Warnings : It is possible to have Focal = 0.
Raises ConstructionError if Focal < 0.0

 gp_Parab2d (const gp_Ax2d &D, const gp_Pnt2d &F, const Standard_Boolean Sense=Standard_True)
 Creates a parabola with the directrix and the focus point.
The sense of parametrization is given by Sense.

 gp_Parab2d (const gp_Ax22d &D, const gp_Pnt2d &F)
 Creates a parabola with the directrix and the focus point.
The Sense of parametrization is given by D.

void SetFocal (const Standard_Real Focal)
 Changes the focal distance of the parabola
Warnings : It is possible to have Focal = 0.
Raises ConstructionError if Focal < 0.0

void SetLocation (const gp_Pnt2d &P)
 Changes the "Location" point of the parabola. It is the
vertex of the parabola.

void SetMirrorAxis (const gp_Ax2d &A)
 Modifies this parabola, by redefining its local coordinate system so that
its origin and "X Direction" become those of the axis
MA. The "Y Direction" of the local coordinate system is
then recomputed. The orientation of the local
coordinate system is not modified.

void SetAxis (const gp_Ax22d &A)
 Changes the local coordinate system of the parabola.
The "Location" point of A becomes the vertex of the parabola.

void Coefficients (Standard_Real &A, Standard_Real &B, Standard_Real &C, Standard_Real &D, Standard_Real &E, Standard_Real &F) const
 Computes the coefficients of the implicit equation of the parabola.
A * (X**2) + B * (Y**2) + 2*C*(X*Y) + 2*D*X + 2*E*Y + F = 0.

gp_Ax2d Directrix () const
 Computes the directrix of the parabola.
The directrix is:

Standard_Real Focal () const
 Returns the distance between the vertex and the focus
of the parabola.

gp_Pnt2d Focus () const
 Returns the focus of the parabola.

gp_Pnt2d Location () const
 Returns the vertex of the parabola.

gp_Ax2d MirrorAxis () const
 Returns the symmetry axis of the parabola.
The "Location" point of this axis is the vertex of the parabola.

gp_Ax22d Axis () const
 Returns the local coordinate system of the parabola.
The "Location" point of this axis is the vertex of the parabola.

Standard_Real Parameter () const
 Returns the distance between the focus and the
directrix of the parabola.

void Reverse ()
gp_Parab2d Reversed () const
 Reverses the orientation of the local coordinate system
of this parabola (the "Y Direction" is reversed).
Therefore, the implicit orientation of this parabola is reversed.
Note:

Standard_Boolean IsDirect () const
 Returns true if the local coordinate system is direct
and false in the other case.

void Mirror (const gp_Pnt2d &P)
gp_Parab2d Mirrored (const gp_Pnt2d &P) const
 Performs the symmetrical transformation of a parabola with respect
to the point P which is the center of the symmetry

void Mirror (const gp_Ax2d &A)
gp_Parab2d Mirrored (const gp_Ax2d &A) const
 Performs the symmetrical transformation of a parabola with respect
to an axis placement which is the axis of the symmetry.

void Rotate (const gp_Pnt2d &P, const Standard_Real Ang)
gp_Parab2d Rotated (const gp_Pnt2d &P, const Standard_Real Ang) const
 Rotates a parabola. P is the center of the rotation.
Ang is the angular value of the rotation in radians.

void Scale (const gp_Pnt2d &P, const Standard_Real S)
gp_Parab2d Scaled (const gp_Pnt2d &P, const Standard_Real S) const
 Scales a parabola. S is the scaling value.
If S is negative the direction of the symmetry axis
"XAxis" is reversed and the direction of the "YAxis" too.

void Transform (const gp_Trsf2d &T)
gp_Parab2d Transformed (const gp_Trsf2d &T) const
 Transforms an parabola with the transformation T from class Trsf2d.

void Translate (const gp_Vec2d &V)
gp_Parab2d Translated (const gp_Vec2d &V) const
 Translates a parabola in the direction of the vector V.
The magnitude of the translation is the vector's magnitude.

void Translate (const gp_Pnt2d &P1, const gp_Pnt2d &P2)
gp_Parab2d Translated (const gp_Pnt2d &P1, const gp_Pnt2d &P2) const
 Translates a parabola from the point P1 to the point P2.

const gp_Ax22d_CSFDB_Getgp_Parab2dpos () const
Standard_Real _CSFDB_Getgp_Parab2dfocalLength () const
void _CSFDB_Setgp_Parab2dfocalLength (const Standard_Real p)

Detailed Description


Constructor & Destructor Documentation


Member Function Documentation

  • a line parallel to the "Y Direction" of the local
    coordinate system of this parabola, and
  • located on the negative side of the axis of symmetry,
    at a distance from the apex which is equal to the focal length of this parabola.
    The directrix is returned as an axis (a gp_Ax2d object),
    the origin of which is situated on the "X Axis" of this parabola.
  • Reverse assigns the result to this parabola, while
  • Reversed creates a new one.

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