-- File:	Geom2d_Conic.cdl
-- Created:	Wed Mar 24 17:59:38 1993
-- Author:	JCV
--		<fid@sdsun2>
-- Copyright:	 Matra Datavision 1993

---Copyright:   Matra Datavision 1991

deferred class Conic from Geom2d inherits Curve from Geom2d

        --- Purpose : The abstract class Conic describes the common
    	-- behavior of conic curves in 2D space and, in
    	-- particular, their general characteristics. The Geom2d
    	-- package provides four specific classes of conics:
    	-- Geom2d_Circle, Geom2d_Ellipse,
    	-- Geom2d_Hyperbola and Geom2d_Parabola.
    	-- A conic is positioned in the plane with a coordinate
    	-- system (gp_Ax22d object), where the origin is the
    	-- center of the conic (or the apex in case of a parabola).
    	-- This coordinate system is the local coordinate
    	-- system of the conic. It gives the conic an explicit
    	-- orientation, determining the direction in which the
    	-- parameter increases along the conic. The "X Axis" of
    	-- the local coordinate system also defines the origin of
    	-- the parameter of the conic.

uses  Ax2d   from gp, 
      Ax22d  from gp,
      Pnt2d  from gp, 
      Vec2d  from gp,
      Shape  from GeomAbs


raises ConstructionError from Standard,
       DomainError       from Standard


is


  SetAxis (me: mutable; A: Ax22d);

    	---Purpose: Modifies this conic, redefining its local coordinate system
    	-- partially, by assigning P as its origin

  SetXAxis (me : mutable; A : Ax2d);
	    	

  SetYAxis (me : mutable; A : Ax2d);
    	---Purpose: Assigns the origin and unit vector of axis A to the
    	-- origin of the local coordinate system of this conic and either:
    	-- - its "X Direction", or
    	-- - its "Y Direction".
    	-- The other unit vector of the local coordinate system
    	-- of this conic is recomputed normal to A, without
    	-- changing the orientation of the local coordinate
    	-- system (right-handed or left-handed).

  SetLocation (me : mutable; P : Pnt2d);
        --- Purpose : Modifies this conic, redefining its local coordinate
    	-- system fully, by assigning A as this coordinate system.


  XAxis (me)  returns Ax2d;
        --- Purpose :
        --  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&


  YAxis (me)  returns Ax2d;
        --- Purpose :
        --  Returns the "YAxis" of the conic.
        --  The "YAxis" is perpendicular to the "Xaxis".
	  

  Eccentricity (me)  returns Real
        --- Purpose :
        --  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
     raises DomainError
     is deferred;


  Location (me)  returns Pnt2d;
        --- Purpose :
        --  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.



  Position (me)   returns Ax22d;
        ---Purpose :
	--  Returns the local coordinates system of the conic.
    	---C++: return const&


  Reverse (me : mutable);
	--- Purpose :
	--  Reverses the direction of parameterization of <me>.
        --  The local coordinate system of the conic is modified.


  ReversedParameter(me; U : Real) returns Real
	---Purpose: Returns the  parameter on the  reversed  curve for
	--          the point of parameter U on <me>.
	--          
  is deferred;


  Continuity (me)   returns Shape from GeomAbs;
        --- Purpose : Returns GeomAbs_CN which is the global continuity of any conic.
        

  IsCN (me; N : Integer)  returns Boolean;
        --- Purpose :
        --  Returns True, the order of continuity of a conic is infinite.




  
fields

  pos : Ax22d is protected;

end;