Open CASCADE Technology 7.7.2
Public Member Functions
Geom2d_Parabola Class Reference

Describes a parabola in the plane (2D space). A parabola is defined by its focal length (i.e. the distance between its focus and its apex) and is positioned in the plane with a coordinate system (gp_Ax22d object) where: More...

#include <Geom2d_Parabola.hxx>

Inheritance diagram for Geom2d_Parabola:
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Public Member Functions

 Geom2d_Parabola (const gp_Parab2d &Prb)
 Creates a parabola from a non persistent one.
 
 Geom2d_Parabola (const gp_Ax2d &MirrorAxis, const Standard_Real Focal, const Standard_Boolean Sense=Standard_True)
 Creates a parabola with its "MirrorAxis" and it's focal length "Focal". MirrorAxis is the axis of symmetry of the curve, it is the "XAxis". The "YAxis" is parallel to the directrix of the parabola and is in the direct sense if Sense is True. The "Location" point of "MirrorAxis" is the vertex of the parabola Raised if Focal < 0.0.
 
 Geom2d_Parabola (const gp_Ax22d &Axis, const Standard_Real Focal)
 Creates a parabola with its Axis and it's focal length "Focal". The XDirection of Axis is the axis of symmetry of the curve, it is the "XAxis". The "YAxis" is parallel to the directrix of the parabola. The "Location" point of "Axis" is the vertex of the parabola. Raised if Focal < 0.0.
 
 Geom2d_Parabola (const gp_Ax2d &D, const gp_Pnt2d &F)
 D is the directrix of the parabola and F the focus point. The symmetry axis "XAxis" of the parabola is normal to the directrix and pass through the focus point F, but its "Location" point is the vertex of the parabola. The "YAxis" of the parabola is parallel to D and its "Location" point is the vertex of the parabola.
 
void SetFocal (const Standard_Real Focal)
 Assigns the value Focal to the focal length of this parabola. Exceptions Standard_ConstructionError if Focal is negative.
 
void SetParab2d (const gp_Parab2d &Prb)
 Converts the gp_Parab2d parabola Prb into this parabola.
 
gp_Parab2d Parab2d () const
 Returns the non persistent parabola from gp with the same geometric properties as <me>.
 
Standard_Real ReversedParameter (const Standard_Real U) const override
 Computes the parameter on the reversed parabola for the point of parameter U on this parabola. For a parabola, the returned value is -U.
 
Standard_Real FirstParameter () const override
 Returns RealFirst from Standard.
 
Standard_Real LastParameter () const override
 Returns RealLast from Standard.
 
Standard_Boolean IsClosed () const override
 Returns False.
 
Standard_Boolean IsPeriodic () const override
 Returns False.
 
gp_Ax2d Directrix () const
 The directrix is parallel to the "YAxis" of the parabola. The "Location" point of the directrix is the intersection point between the directrix and the symmetry axis ("XAxis") of the parabola.
 
Standard_Real Eccentricity () const override
 Returns the eccentricity e = 1.0.
 
gp_Pnt2d Focus () const
 Computes the focus of this parabola The focus is on the positive side of the "X Axis" of the local coordinate system of the parabola.
 
Standard_Real Focal () const
 Computes the focal length of this parabola. The focal length is the distance between the apex and the focus of the parabola.
 
Standard_Real Parameter () const
 Computes the parameter of this parabola, which is the distance between its focus and its directrix. This distance is twice the focal length. If P is the parameter of the parabola, the equation of the parabola in its local coordinate system is: Y**2 = 2.*P*X.
 
void D0 (const Standard_Real U, gp_Pnt2d &P) const override
 Returns in P the point of parameter U. If U = 0 the returned point is the origin of the XAxis and the YAxis of the parabola and it is the vertex of the parabola. P = S + F * (U * U * XDir + * U * YDir) where S is the vertex of the parabola, XDir the XDirection and YDir the YDirection of the parabola's local coordinate system.
 
void D1 (const Standard_Real U, gp_Pnt2d &P, gp_Vec2d &V1) const override
 Returns the point P of parameter U and the first derivative V1.
 
void D2 (const Standard_Real U, gp_Pnt2d &P, gp_Vec2d &V1, gp_Vec2d &V2) const override
 Returns the point P of parameter U, the first and second derivatives V1 and V2.
 
void D3 (const Standard_Real U, gp_Pnt2d &P, gp_Vec2d &V1, gp_Vec2d &V2, gp_Vec2d &V3) const override
 Returns the point P of parameter U, the first second and third derivatives V1 V2 and V3.
 
gp_Vec2d DN (const Standard_Real U, const Standard_Integer N) const override
 For the point of parameter U of this parabola, computes the vector corresponding to the Nth derivative. Exceptions Standard_RangeError if N is less than 1.
 
void Transform (const gp_Trsf2d &T) override
 Applies the transformation T to this parabola.
 
Standard_Real TransformedParameter (const Standard_Real U, const gp_Trsf2d &T) const override
 Computes the parameter on the transformed parabola, for the point of parameter U on this parabola. For a parabola, the returned value is equal to U multiplied by the scale factor of transformation T.
 
Standard_Real ParametricTransformation (const gp_Trsf2d &T) const override
 Returns a coefficient to compute the parameter on the transformed curve for the transform of the point on <me>.
 
Handle< Geom2d_GeometryCopy () const override
 Creates a new object, which is a copy of this parabola.
 
virtual void DumpJson (Standard_OStream &theOStream, Standard_Integer theDepth=-1) const override
 Dumps the content of me into the stream.
 
- Public Member Functions inherited from Geom2d_Conic
void SetAxis (const gp_Ax22d &theA)
 Modifies this conic, redefining its local coordinate system partially, by assigning theA as its axis.
 
void SetXAxis (const gp_Ax2d &theAX)
 Assigns the origin and unit vector of axis theA to the origin of the local coordinate system of this conic and X Direction. The other unit vector of the local coordinate system of this conic is recomputed normal to theA, without changing the orientation of the local coordinate system (right-handed or left-handed).
 
void SetYAxis (const gp_Ax2d &theAY)
 Assigns the origin and unit vector of axis theA to the origin of the local coordinate system of this conic and Y Direction. The other unit vector of the local coordinate system of this conic is recomputed normal to theA, without changing the orientation of the local coordinate system (right-handed or left-handed).
 
void SetLocation (const gp_Pnt2d &theP)
 Modifies this conic, redefining its local coordinate system partially, by assigning theP as its origin.
 
gp_Ax2d XAxis () const
 Returns the "XAxis" of the conic. This axis defines the origin of parametrization of the conic. This axis and the "Yaxis" define the local coordinate system of the conic. -C++: return const&.
 
gp_Ax2d YAxis () const
 Returns the "YAxis" of the conic. The "YAxis" is perpendicular to the "Xaxis".
 
virtual Standard_Real Eccentricity () const =0
 returns the eccentricity value of the conic e. e = 0 for a circle 0 < e < 1 for an ellipse (e = 0 if MajorRadius = MinorRadius) e > 1 for a hyperbola e = 1 for a parabola
 
const gp_Pnt2dLocation () const
 Returns the location point of the conic. For the circle, the ellipse and the hyperbola it is the center of the conic. For the parabola it is the vertex of the parabola.
 
const gp_Ax22dPosition () const
 Returns the local coordinates system of the conic.
 
void Reverse () override
 Reverses the direction of parameterization of <me>. The local coordinate system of the conic is modified.
 
virtual Standard_Real ReversedParameter (const Standard_Real U) const override=0
 Returns the parameter on the reversed curve for the point of parameter U on <me>.
 
GeomAbs_Shape Continuity () const override
 Returns GeomAbs_CN which is the global continuity of any conic.
 
Standard_Boolean IsCN (const Standard_Integer N) const override
 Returns True, the order of continuity of a conic is infinite.
 
virtual void DumpJson (Standard_OStream &theOStream, Standard_Integer theDepth=-1) const override
 Dumps the content of me into the stream.
 
- Public Member Functions inherited from Geom2d_Curve
virtual void Reverse ()=0
 Changes the direction of parametrization of <me>. The "FirstParameter" and the "LastParameter" are not changed but the orientation of the curve is modified. If the curve is bounded the StartPoint of the initial curve becomes the EndPoint of the reversed curve and the EndPoint of the initial curve becomes the StartPoint of the reversed curve.
 
virtual Standard_Real ReversedParameter (const Standard_Real U) const =0
 Computes the parameter on the reversed curve for the point of parameter U on this curve. Note: The point of parameter U on this curve is identical to the point of parameter ReversedParameter(U) on the reversed curve.
 
virtual Standard_Real TransformedParameter (const Standard_Real U, const gp_Trsf2d &T) const
 Computes the parameter on the curve transformed by T for the point of parameter U on this curve. Note: this function generally returns U but it can be redefined (for example, on a line).
 
virtual Standard_Real ParametricTransformation (const gp_Trsf2d &T) const
 Returns the coefficient required to compute the parametric transformation of this curve when transformation T is applied. This coefficient is the ratio between the parameter of a point on this curve and the parameter of the transformed point on the new curve transformed by T. Note: this function generally returns 1. but it can be redefined (for example, on a line).
 
Handle< Geom2d_CurveReversed () const
 Creates a reversed duplicate Changes the orientation of this curve. The first and last parameters are not changed, but the parametric direction of the curve is reversed. If the curve is bounded:
 
virtual Standard_Real FirstParameter () const =0
 Returns the value of the first parameter. Warnings : It can be RealFirst or RealLast from package Standard if the curve is infinite.
 
virtual Standard_Real LastParameter () const =0
 Value of the last parameter. Warnings : It can be RealFirst or RealLast from package Standard if the curve is infinite.
 
virtual Standard_Boolean IsClosed () const =0
 Returns true if the curve is closed. Examples : Some curves such as circle are always closed, others such as line are never closed (by definition). Some Curves such as OffsetCurve can be closed or not. These curves are considered as closed if the distance between the first point and the last point of the curve is lower or equal to the Resolution from package gp which is a fixed criterion independent of the application.
 
virtual Standard_Boolean IsPeriodic () const =0
 Returns true if the parameter of the curve is periodic. It is possible only if the curve is closed and if the following relation is satisfied : for each parametric value U the distance between the point P(u) and the point P (u + T) is lower or equal to Resolution from package gp, T is the period and must be a constant. There are three possibilities : . the curve is never periodic by definition (SegmentLine) . the curve is always periodic by definition (Circle) . the curve can be defined as periodic (BSpline). In this case a function SetPeriodic allows you to give the shape of the curve. The general rule for this case is : if a curve can be periodic or not the default periodicity set is non periodic and you have to turn (explicitly) the curve into a periodic curve if you want the curve to be periodic.
 
virtual Standard_Real Period () const
 Returns the period of this curve. raises if the curve is not periodic.
 
virtual GeomAbs_Shape Continuity () const =0
 It is the global continuity of the curve : C0 : only geometric continuity, C1 : continuity of the first derivative all along the Curve, C2 : continuity of the second derivative all along the Curve, C3 : continuity of the third derivative all along the Curve, G1 : tangency continuity all along the Curve, G2 : curvature continuity all along the Curve, CN : the order of continuity is infinite.
 
virtual Standard_Boolean IsCN (const Standard_Integer N) const =0
 Returns true if the degree of continuity of this curve is at least N. Exceptions Standard_RangeError if N is less than 0.
 
virtual void D0 (const Standard_Real U, gp_Pnt2d &P) const =0
 Returns in P the point of parameter U. If the curve is periodic then the returned point is P(U) with U = Ustart + (U - Uend) where Ustart and Uend are the parametric bounds of the curve.
 
virtual void D1 (const Standard_Real U, gp_Pnt2d &P, gp_Vec2d &V1) const =0
 Returns the point P of parameter U and the first derivative V1. Raised if the continuity of the curve is not C1.
 
virtual void D2 (const Standard_Real U, gp_Pnt2d &P, gp_Vec2d &V1, gp_Vec2d &V2) const =0
 Returns the point P of parameter U, the first and second derivatives V1 and V2. Raised if the continuity of the curve is not C2.
 
virtual void D3 (const Standard_Real U, gp_Pnt2d &P, gp_Vec2d &V1, gp_Vec2d &V2, gp_Vec2d &V3) const =0
 Returns the point P of parameter U, the first, the second and the third derivative. Raised if the continuity of the curve is not C3.
 
virtual gp_Vec2d DN (const Standard_Real U, const Standard_Integer N) const =0
 For the point of parameter U of this curve, computes the vector corresponding to the Nth derivative. Exceptions StdFail_UndefinedDerivative if:
 
gp_Pnt2d Value (const Standard_Real U) const
 Computes the point of parameter U on <me>. If the curve is periodic then the returned point is P(U) with U = Ustart + (U - Uend) where Ustart and Uend are the parametric bounds of the curve.
 
virtual void DumpJson (Standard_OStream &theOStream, Standard_Integer theDepth=-1) const override
 Dumps the content of me into the stream.
 
- Public Member Functions inherited from Geom2d_Geometry
void Mirror (const gp_Pnt2d &P)
 Performs the symmetrical transformation of a Geometry with respect to the point P which is the center of the symmetry and assigns the result to this geometric object.
 
void Mirror (const gp_Ax2d &A)
 Performs the symmetrical transformation of a Geometry with respect to an axis placement which is the axis of the symmetry.
 
void Rotate (const gp_Pnt2d &P, const Standard_Real Ang)
 Rotates a Geometry. 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)
 Scales a Geometry. S is the scaling value.
 
void Translate (const gp_Vec2d &V)
 Translates a Geometry. V is the vector of the translation.
 
void Translate (const gp_Pnt2d &P1, const gp_Pnt2d &P2)
 Translates a Geometry from the point P1 to the point P2.
 
virtual void Transform (const gp_Trsf2d &T)=0
 Transformation of a geometric object. This tansformation can be a translation, a rotation, a symmetry, a scaling or a complex transformation obtained by combination of the previous elementaries transformations. (see class Transformation of the package Geom2d). The following transformations have the same properties as the previous ones but they don't modified the object itself. A copy of the object is returned.
 
Handle< Geom2d_GeometryMirrored (const gp_Pnt2d &P) const
 
Handle< Geom2d_GeometryMirrored (const gp_Ax2d &A) const
 
Handle< Geom2d_GeometryRotated (const gp_Pnt2d &P, const Standard_Real Ang) const
 
Handle< Geom2d_GeometryScaled (const gp_Pnt2d &P, const Standard_Real S) const
 
Handle< Geom2d_GeometryTransformed (const gp_Trsf2d &T) const
 
Handle< Geom2d_GeometryTranslated (const gp_Vec2d &V) const
 
Handle< Geom2d_GeometryTranslated (const gp_Pnt2d &P1, const gp_Pnt2d &P2) const
 
virtual Handle< Geom2d_GeometryCopy () const =0
 
virtual void DumpJson (Standard_OStream &theOStream, Standard_Integer theDepth=-1) const
 Dumps the content of me into the stream.
 
- Public Member Functions inherited from Standard_Transient
 Standard_Transient ()
 Empty constructor.
 
 Standard_Transient (const Standard_Transient &)
 Copy constructor – does nothing.
 
Standard_Transientoperator= (const Standard_Transient &)
 Assignment operator, needed to avoid copying reference counter.
 
virtual ~Standard_Transient ()
 Destructor must be virtual.
 
virtual void Delete () const
 Memory deallocator for transient classes.
 
virtual const opencascade::handle< Standard_Type > & DynamicType () const
 Returns a type descriptor about this object.
 
Standard_Boolean IsInstance (const opencascade::handle< Standard_Type > &theType) const
 Returns a true value if this is an instance of Type.
 
Standard_Boolean IsInstance (const Standard_CString theTypeName) const
 Returns a true value if this is an instance of TypeName.
 
Standard_Boolean IsKind (const opencascade::handle< Standard_Type > &theType) const
 Returns true if this is an instance of Type or an instance of any class that inherits from Type. Note that multiple inheritance is not supported by OCCT RTTI mechanism.
 
Standard_Boolean IsKind (const Standard_CString theTypeName) const
 Returns true if this is an instance of TypeName or an instance of any class that inherits from TypeName. Note that multiple inheritance is not supported by OCCT RTTI mechanism.
 
Standard_TransientThis () const
 Returns non-const pointer to this object (like const_cast). For protection against creating handle to objects allocated in stack or call from constructor, it will raise exception Standard_ProgramError if reference counter is zero.
 
Standard_Integer GetRefCount () const
 Get the reference counter of this object.
 
void IncrementRefCounter () const
 Increments the reference counter of this object.
 
Standard_Integer DecrementRefCounter () const
 Decrements the reference counter of this object; returns the decremented value.
 

Additional Inherited Members

- Public Types inherited from Standard_Transient
typedef void base_type
 Returns a type descriptor about this object.
 
- Static Public Member Functions inherited from Standard_Transient
static const char * get_type_name ()
 Returns a type descriptor about this object.
 
static const opencascade::handle< Standard_Type > & get_type_descriptor ()
 Returns type descriptor of Standard_Transient class.
 
- Protected Attributes inherited from Geom2d_Conic
gp_Ax22d pos
 

Detailed Description

Describes a parabola in the plane (2D space). A parabola is defined by its focal length (i.e. the distance between its focus and its apex) and is positioned in the plane with a coordinate system (gp_Ax22d object) where:

Constructor & Destructor Documentation

◆ Geom2d_Parabola() [1/4]

Geom2d_Parabola::Geom2d_Parabola ( const gp_Parab2d Prb)

Creates a parabola from a non persistent one.

◆ Geom2d_Parabola() [2/4]

Geom2d_Parabola::Geom2d_Parabola ( const gp_Ax2d MirrorAxis,
const Standard_Real  Focal,
const Standard_Boolean  Sense = Standard_True 
)

Creates a parabola with its "MirrorAxis" and it's focal length "Focal". MirrorAxis is the axis of symmetry of the curve, it is the "XAxis". The "YAxis" is parallel to the directrix of the parabola and is in the direct sense if Sense is True. The "Location" point of "MirrorAxis" is the vertex of the parabola Raised if Focal < 0.0.

◆ Geom2d_Parabola() [3/4]

Geom2d_Parabola::Geom2d_Parabola ( const gp_Ax22d Axis,
const Standard_Real  Focal 
)

Creates a parabola with its Axis and it's focal length "Focal". The XDirection of Axis is the axis of symmetry of the curve, it is the "XAxis". The "YAxis" is parallel to the directrix of the parabola. The "Location" point of "Axis" is the vertex of the parabola. Raised if Focal < 0.0.

◆ Geom2d_Parabola() [4/4]

Geom2d_Parabola::Geom2d_Parabola ( const gp_Ax2d D,
const gp_Pnt2d F 
)

D is the directrix of the parabola and F the focus point. The symmetry axis "XAxis" of the parabola is normal to the directrix and pass through the focus point F, but its "Location" point is the vertex of the parabola. The "YAxis" of the parabola is parallel to D and its "Location" point is the vertex of the parabola.

Member Function Documentation

◆ Copy()

Handle< Geom2d_Geometry > Geom2d_Parabola::Copy ( ) const
overridevirtual

Creates a new object, which is a copy of this parabola.

Implements Geom2d_Geometry.

◆ D0()

void Geom2d_Parabola::D0 ( const Standard_Real  U,
gp_Pnt2d P 
) const
overridevirtual

Returns in P the point of parameter U. If U = 0 the returned point is the origin of the XAxis and the YAxis of the parabola and it is the vertex of the parabola. P = S + F * (U * U * XDir + * U * YDir) where S is the vertex of the parabola, XDir the XDirection and YDir the YDirection of the parabola's local coordinate system.

Implements Geom2d_Curve.

◆ D1()

void Geom2d_Parabola::D1 ( const Standard_Real  U,
gp_Pnt2d P,
gp_Vec2d V1 
) const
overridevirtual

Returns the point P of parameter U and the first derivative V1.

Implements Geom2d_Curve.

◆ D2()

void Geom2d_Parabola::D2 ( const Standard_Real  U,
gp_Pnt2d P,
gp_Vec2d V1,
gp_Vec2d V2 
) const
overridevirtual

Returns the point P of parameter U, the first and second derivatives V1 and V2.

Implements Geom2d_Curve.

◆ D3()

void Geom2d_Parabola::D3 ( const Standard_Real  U,
gp_Pnt2d P,
gp_Vec2d V1,
gp_Vec2d V2,
gp_Vec2d V3 
) const
overridevirtual

Returns the point P of parameter U, the first second and third derivatives V1 V2 and V3.

Implements Geom2d_Curve.

◆ Directrix()

gp_Ax2d Geom2d_Parabola::Directrix ( ) const

The directrix is parallel to the "YAxis" of the parabola. The "Location" point of the directrix is the intersection point between the directrix and the symmetry axis ("XAxis") of the parabola.

◆ DN()

gp_Vec2d Geom2d_Parabola::DN ( const Standard_Real  U,
const Standard_Integer  N 
) const
overridevirtual

For the point of parameter U of this parabola, computes the vector corresponding to the Nth derivative. Exceptions Standard_RangeError if N is less than 1.

Implements Geom2d_Curve.

◆ DumpJson()

virtual void Geom2d_Parabola::DumpJson ( Standard_OStream theOStream,
Standard_Integer  theDepth = -1 
) const
overridevirtual

Dumps the content of me into the stream.

Reimplemented from Geom2d_Conic.

◆ Eccentricity()

Standard_Real Geom2d_Parabola::Eccentricity ( ) const
overridevirtual

Returns the eccentricity e = 1.0.

Implements Geom2d_Conic.

◆ FirstParameter()

Standard_Real Geom2d_Parabola::FirstParameter ( ) const
overridevirtual

Returns RealFirst from Standard.

Implements Geom2d_Curve.

◆ Focal()

Standard_Real Geom2d_Parabola::Focal ( ) const

Computes the focal length of this parabola. The focal length is the distance between the apex and the focus of the parabola.

◆ Focus()

gp_Pnt2d Geom2d_Parabola::Focus ( ) const

Computes the focus of this parabola The focus is on the positive side of the "X Axis" of the local coordinate system of the parabola.

◆ IsClosed()

Standard_Boolean Geom2d_Parabola::IsClosed ( ) const
overridevirtual

Returns False.

Implements Geom2d_Curve.

◆ IsPeriodic()

Standard_Boolean Geom2d_Parabola::IsPeriodic ( ) const
overridevirtual

Returns False.

Implements Geom2d_Curve.

◆ LastParameter()

Standard_Real Geom2d_Parabola::LastParameter ( ) const
overridevirtual

Returns RealLast from Standard.

Implements Geom2d_Curve.

◆ Parab2d()

gp_Parab2d Geom2d_Parabola::Parab2d ( ) const

Returns the non persistent parabola from gp with the same geometric properties as <me>.

◆ Parameter()

Standard_Real Geom2d_Parabola::Parameter ( ) const

Computes the parameter of this parabola, which is the distance between its focus and its directrix. This distance is twice the focal length. If P is the parameter of the parabola, the equation of the parabola in its local coordinate system is: Y**2 = 2.*P*X.

◆ ParametricTransformation()

Standard_Real Geom2d_Parabola::ParametricTransformation ( const gp_Trsf2d T) const
overridevirtual

Returns a coefficient to compute the parameter on the transformed curve for the transform of the point on <me>.

Transformed(T)->Value(U * ParametricTransformation(T))

is the same point as

Value(U).Transformed(T)

This methods returns T.ScaleFactor()

Reimplemented from Geom2d_Curve.

◆ ReversedParameter()

Standard_Real Geom2d_Parabola::ReversedParameter ( const Standard_Real  U) const
overridevirtual

Computes the parameter on the reversed parabola for the point of parameter U on this parabola. For a parabola, the returned value is -U.

Implements Geom2d_Conic.

◆ SetFocal()

void Geom2d_Parabola::SetFocal ( const Standard_Real  Focal)

Assigns the value Focal to the focal length of this parabola. Exceptions Standard_ConstructionError if Focal is negative.

◆ SetParab2d()

void Geom2d_Parabola::SetParab2d ( const gp_Parab2d Prb)

Converts the gp_Parab2d parabola Prb into this parabola.

◆ Transform()

void Geom2d_Parabola::Transform ( const gp_Trsf2d T)
overridevirtual

Applies the transformation T to this parabola.

Implements Geom2d_Geometry.

◆ TransformedParameter()

Standard_Real Geom2d_Parabola::TransformedParameter ( const Standard_Real  U,
const gp_Trsf2d T 
) const
overridevirtual

Computes the parameter on the transformed parabola, for the point of parameter U on this parabola. For a parabola, the returned value is equal to U multiplied by the scale factor of transformation T.

Reimplemented from Geom2d_Curve.


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