path: root/src/gp/gp_Elips2d.cdl

---Copyright:   Matra Datavision 1991, 1992

class Elips2d   from gp  inherits Storable

        --- Purpose :
	-- Describes an ellipse in the plane (2D space).
        -- An ellipse is defined by its major and minor radii and
        -- positioned in the plane with a coordinate system (a
        -- gp_Ax22d object) as follows:
        -- -   the origin of the coordinate system is the center of the ellipse,
        -- -   its "X Direction" defines the major axis of the ellipse, and
        -- -   its "Y Direction" defines the minor axis of the ellipse.
        -- This coordinate system is the "local coordinate system"
        -- of the ellipse. Its orientation (direct or indirect) gives an
        -- implicit orientation to the ellipse. In this coordinate
        -- system, the equation of the ellipse is:
        -- X*X / (MajorRadius**2) + Y*Y / (MinorRadius**2) = 1.0
        -- See Also
        -- gce_MakeElips2d which provides functions for more
        -- complex ellipse constructions
        -- Geom2d_Ellipse which provides additional functions for
        -- constructing ellipses and works, in particular, with the
        -- parametric equations of ellipses 

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

raises ConstructionError from Standard


is
  Create   returns Elips2d;
        ---C++:inline
        --- Purpose : Creates an indefinite ellipse.


  Create (MajorAxis : Ax2d; 
    	  MajorRadius, MinorRadius : Real;
    	  Sense : Boolean from Standard = Standard_True)
     returns Elips2d
        ---C++:inline
        --- Purpose :
	--  Creates an ellipse with the major axis, the major and the
        --  minor radius. The location of the MajorAxis is the center
        --  of the  ellipse.
	--  The sense of parametrization is given by Sense.
        --  Warnings :
        --  It is possible to create an ellipse with 
        --  MajorRadius = MinorRadius.    
    	--  Raises ConstructionError if MajorRadius < MinorRadius or MinorRadius < 0.0
     raises ConstructionError;
	

  Create (A : Ax22d; MajorRadius, MinorRadius : Real)
     returns Elips2d
        --- Purpose :  Creates an ellipse with radii MajorRadius and
    	--   MinorRadius, positioned in the plane by coordinate system A where:
    	--   -   the origin of A is the center of the ellipse,
    	--   -   the "X Direction" of A defines the major axis of
    	--    the ellipse, that is, the major radius MajorRadius
    	--    is measured along this axis, and
    	--   -   the "Y Direction" of A defines the minor axis of
    	--    the ellipse, that is, the minor radius MinorRadius
    	--    is measured along this axis, and
    	--   -   the orientation (direct or indirect sense) of A
    	--    gives the orientation of the ellipse.
        --  Warnings :
        --  It is possible to create an ellipse with 
        --  MajorRadius = MinorRadius.  
    	-- Raises ConstructionError if MajorRadius < MinorRadius or MinorRadius < 0.0

     raises ConstructionError;
	

  SetLocation (me : in out; P : Pnt2d)  is static;
        --- Purpose : Modifies this ellipse, by redefining its local coordinate system so that
    	-- -   its origin becomes P. 


  SetMajorRadius (me : in out; MajorRadius : Real)
        --- Purpose : Changes the value of the major radius.
    	-- Raises ConstructionError if MajorRadius < MinorRadius.
     raises ConstructionError
     is static;


  SetMinorRadius (me : in out; MinorRadius : Real)
        --- Purpose : Changes the value of the minor radius.
    	-- Raises ConstructionError if MajorRadius < MinorRadius or MinorRadius < 0.0
     raises ConstructionError
	
     is static;


  SetAxis (me : in out; A : Ax22d)  is static;
        --- Purpose : Modifies this ellipse, by redefining its local coordinate system so that
        --    it becomes A.


  SetXAxis (me : in out; A : Ax2d)  is static;
        --- Purpose : Modifies this ellipse, by redefining its local coordinate system so that
      	--   its origin and its "X Direction"  become those
    	-- of the axis A. The "Y  Direction"  is then
    	--   recomputed. The orientation of the local coordinate
    	--   system is not modified.


  SetYAxis (me : in out; A : Ax2d)  is static;
        --- Purpose : Modifies this ellipse, by redefining its local coordinate system so that
      	--   its origin and its "Y Direction"  become those
    	-- of the axis A. The "X  Direction"  is then
    	--   recomputed. The orientation of the local coordinate
    	--   system is not modified.


  Area (me)  returns Real  is static;
 	--- Purpose : Computes the area of the ellipse.
        ---C++: inline


  Coefficients (me; A, B, C, D, E, F : out Real)  is static;
        --- Purpose :
        --  Returns the coefficients of the implicit equation of the ellipse.
        --  A * (X**2) + B * (Y**2) + 2*C*(X*Y) + 2*D*X + 2*E*Y + F = 0.


  Directrix1 (me)   returns Ax2d
        ---C++: inline
        --- Purpose :
        --  This directrix is the line normal to the XAxis of the ellipse
        --  in the local plane (Z = 0) at a distance d = MajorRadius / e 
        --  from the center of the ellipse, where e is the eccentricity of
        --  the ellipse.
        --  This line is parallel to the "YAxis". The intersection point
        --  between directrix1 and the "XAxis" is the location point of the
        --  directrix1. This point is on the positive side of the "XAxis".
     raises ConstructionError
	--- Purpose : 
	--  Raised if Eccentricity = 0.0. (The ellipse degenerates into a
	--  circle)
     is static;


  Directrix2 (me)   returns Ax2d
        ---C++: inline
        --- Purpose :
        --  This line is obtained by the symmetrical transformation 
        --  of "Directrix1" with respect to the minor axis of the ellipse.
     raises ConstructionError
	--- Purpose :
	--  Raised if Eccentricity = 0.0. (The ellipse degenerates into a
	--  circle).
     is static;


  Eccentricity (me)  returns Real   is static;
        ---C++: inline
        --- Purpose :
	--  Returns the eccentricity of the ellipse  between 0.0 and 1.0
	--  If f is the distance between the center of the ellipse and
	--  the Focus1 then the eccentricity e = f / MajorRadius.
	--  Returns 0 if MajorRadius = 0.


  Focal (me)  returns Real is static;
        ---C++: inline
        --- Purpose :
	--  Returns the distance between the center of the ellipse
	--  and focus1 or focus2.


  Focus1 (me)   returns Pnt2d   is static;
        ---C++: inline
	--- Purpose :
	--  Returns the first focus of the ellipse. This focus is on the
        --  positive side of the major axis of the ellipse.


  Focus2 (me)   returns Pnt2d   is static;
        ---C++: inline
	--- Purpose :
	--  Returns the second focus of the ellipse. This focus is on the
        --  negative side of the major axis of the ellipse.


  Location (me)   returns Pnt2d  is static;
        ---C++:inline
        --- Purpose : Returns the center of the ellipse.
    	---C++: return const&
  

  MajorRadius (me)  returns Real    is static;
	--- Purpose : Returns the major radius of the Ellipse.
        ---C++: inline


  MinorRadius (me)   returns Real   is static;
	--- Purpose : Returns the minor radius of the Ellipse.
        ---C++: inline


  Parameter (me)  returns Real   is static;
        ---C++: inline
        --- Purpose :
        --  Returns p = (1 - e * e) * MajorRadius where e is the eccentricity 
        --  of the ellipse.
	--  Returns 0 if MajorRadius = 0


  Axis (me)  returns Ax22d  is static;
        --- Purpose : Returns the major axis of the ellipse.
        ---C++: inline
    	---C++: return const&


  XAxis (me)  returns Ax2d  is static;
        ---C++:inline
        --- Purpose : Returns the major axis of the ellipse.


  YAxis (me)  returns Ax2d  is static;
        ---C++:inline
        --- Purpose : Returns the minor axis of the ellipse.
       

        --- Purpose : Reverses the direction of the circle.

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

  Reversed (me)  returns Elips2d  is static;
        ---C++:inline

  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 Elips2d  is static;

   --- Purpose :
        --  Performs the symmetrical transformation of a ellipse 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 Elips2d  is static;


        --- Purpose :
        --  Performs the symmetrical transformation of a ellipse with respect 
        --  to an axis placement which is the axis of the symmetry.

  Rotate (me : in out; P : Pnt2d; Ang : Real)  
         is static;

  Rotated (me; P : Pnt2d; Ang : Real)  returns Elips2d  is static;



  Scale (me : in out; P : Pnt2d; S : Real)          is static;

  Scaled (me; P : Pnt2d; S : Real)  returns Elips2d  is static;
        --- Purpose : 
        --  Scales a ellipse. S is the scaling value.

     
  Transform (me : in out; T : Trsf2d) 
            is static;

  Transformed (me; T : Trsf2d)  returns Elips2d   is static;
   --- Purpose :
        --  Transforms an ellipse with the transformation T from class Trsf2d.




  Translate (me : in out; V : Vec2d)            is static;

  Translated (me; V : Vec2d)   returns Elips2d  is static;

        --- Purpose :
        --  Translates a ellipse 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;

  Translated (me; P1, P2 : Pnt2d)   returns Elips2d  is static;

        --- Purpose :
        --  Translates a ellipse from the point P1 to the point P2.



fields

     pos         : Ax22d;
     majorRadius : Real;
     minorRadius : Real;

end;