path: root/src/gp/gp_Parab2d.cdl

---Copyright:   Matra Datavision 1991

class Parab2d   from gp   inherits Storable

        ---Purpose: 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:
        -- -   the origin of the coordinate system is on the apex of
        --   the parabola, and
        -- -   the "X Axis" of the coordinate system is the axis of
        --   symmetry; the parabola is on the positive side of this axis.
        -- This coordinate system is the "local coordinate system"
        -- of the parabola. Its orientation (direct or indirect sense)
        -- gives an implicit orientation to the parabola.
        -- In this coordinate system, the equation for the parabola is:
        -- Y**2 = (2*P) * X.
        -- where P, referred to as the parameter of the parabola, is
        -- the distance between the focus and the directrix (P is
        -- twice the focal length).
        -- See Also
        -- GCE2d_MakeParab2d which provides functions for
        -- more complex parabola constructions
        -- Geom2d_Parabola which provides additional functions
        -- for constructing parabolas and works, in particular, with
        -- the parametric equations of parabolas


uses Ax2d   from gp,
     Ax22d  from gp, 
     Pnt2d  from gp,
     Trsf2d from gp,
     Vec2d  from gp

raises ConstructionError from Standard


is

 

  Create   returns  Parab2d;
        ---C++: inline
        --- Purpose : Creates an indefinite parabola.


  Create (MirrorAxis : Ax2d; 
    	  Focal : Real;
    	  Sense : Boolean from Standard = Standard_True)  returns Parab2d
        ---C++: inline
        --- Purpose :
        --  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

     raises ConstructionError;


  Create (A     : Ax22d; 
    	  Focal : Real)  returns Parab2d
        ---C++: inline
        --- Purpose :
        --  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

     raises ConstructionError;


  Create (D : Ax2d; 
    	  F : Pnt2d;
    	  Sense : Boolean from Standard = Standard_True)  returns Parab2d;
        --- Purpose :
        --  Creates a parabola with the directrix and the focus point.
	--  The sense of parametrization is given by Sense.


  Create (D : Ax22d; F : Pnt2d)  returns Parab2d;
        --- Purpose :
        --  Creates a parabola with the directrix and the focus point.
        --  The Sense of parametrization is given by D.


  SetFocal (me : in out; Focal : Real)
        ---C++: inline
        --- Purpose :
        --  Changes the focal distance of the parabola
        -- Warnings : It is possible to have Focal = 0. 
        -- Raises ConstructionError if Focal < 0.0

     raises ConstructionError
     is static;


  SetLocation (me : in out; P : Pnt2d)  is static;
        ---C++: inline
        --- Purpose : 
        --  Changes the "Location" point of the parabola. It is the 
        --  vertex of the parabola.

  
  SetMirrorAxis (me : in out; A : Ax2d)   is static;
        ---C++: inline
        --- Purpose : 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.
        

  SetAxis (me : in out; A : Ax22d)   is static;
        ---C++: inline
        --- Purpose :
        --  Changes the local coordinate system of the parabola.
        --  The "Location" point of A becomes the vertex of the parabola.
        

  Coefficients (me; A, B, C, D, E, F : out Real)   is static;
        --- Purpose :
        --  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.


  Directrix (me)   returns Ax2d   is static;
        ---C++: inline
        --- Purpose :
        --  Computes the directrix of the parabola.
        -- The directrix is:
        -- -   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.


  Focal (me)  returns Real  is static;
        ---C++: inline
	--- Purpose : 
	--  Returns the distance between the vertex and the focus
	--  of the parabola.


  Focus (me)   returns Pnt2d   is static;
        ---C++: inline
	--- Purpose : Returns the focus of the parabola.


  Location (me)  returns Pnt2d   is static;
        ---C++: inline
        --- Purpose : Returns the vertex of the parabola.


  MirrorAxis (me)  returns Ax2d   is static;
        ---C++: inline
        --- Purpose :
        --  Returns the symmetry axis of the parabola.
        --  The "Location" point of this axis is the vertex of the parabola.

  Axis (me)  returns Ax22d   is static;
        ---C++: inline
        --- Purpose :
        --  Returns the local coordinate system of the parabola.
        --  The "Location" point of this axis is the vertex of the parabola.

  Parameter (me)   returns Real  is static;
        ---C++: inline
        --- Purpose :
	--  Returns the distance between the focus and the
        --  directrix of the parabola.




  Reverse (me : in out)         is static;
        ---C++: inline

  Reversed (me)  returns Parab2d  is static;
        ---C++: inline
        ---Purpose:
        -- 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:
        -- -   Reverse assigns the result to this parabola, while
        -- -   Reversed creates a new one.
  
  IsDirect (me)  returns Boolean  is static;
        ---C++: inline
        --- Purpose : Returns true if the local coordinate system is direct
        --            and false in the other case.

  Mirror (me : in out; P : Pnt2d)            is static;

  Mirrored (me; P : Pnt2d)  returns Parab2d  is static;


        --- Purpose :
        --  Performs the symmetrical transformation of a parabola with respect 
        --  to the point P which is the center of the symmetry


  Mirror (me : in out; A : Ax2d)            is static;

  Mirrored (me; A : Ax2d)  returns Parab2d  is static;
       --- Purpose :
        --  Performs the symmetrical transformation of a parabola with respect 
        --  to an axis placement which is the axis of the symmetry.


       

  Rotate (me : in out; P : Pnt2d; Ang : Real)           is static;
        ---C++: inline

  Rotated (me; P : Pnt2d; Ang : Real)  returns Parab2d  is static;
        ---C++: inline
        --- Purpose :
        --  Rotates a parabola. P is the center of the rotation.
        --  Ang is the angular value of the rotation in radians.

  

  Scale (me : in out; P : Pnt2d; S : Real)          is static;
        ---C++: inline

  Scaled (me; P : Pnt2d; S : Real)  returns Parab2d  is static;
        ---C++: inline
        --- Purpose : 
        --  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.



  Transform (me : in out; T : Trsf2d)             is static;
        ---C++: inline

  Transformed (me; T : Trsf2d)  returns Parab2d   is static;
        ---C++: inline
        --- Purpose :
        --  Transforms an parabola with the transformation T from class Trsf2d.




  Translate (me : in out; V : Vec2d)            is static;
        ---C++: inline

  Translated (me; V : Vec2d)   returns Parab2d  is static;
        ---C++: inline
        --- Purpose :
        --  Translates a parabola in the direction of the vector V.
        --  The magnitude of the translation is the vector's magnitude.


  

  Translate (me : in out; P1, P2 : Pnt2d )           is static;
        ---C++: inline

  Translated (me; P1, P2 : Pnt2d)   returns Parab2d  is static;
        ---C++: inline
        --- Purpose :
        --  Translates a parabola from the point P1 to the point P2.


fields

  pos         : Ax22d;
  focalLength : Real;

end;