-- File:	Extrema_ExtElC2d.cdl
-- Created:	Tue Jan  4 11:37:09 1994
-- Author:	Christophe MARION
--		<cma@sdsun1>
---Copyright:	 Matra Datavision 1994


class   ExtElC2d from Extrema 
	---Purpose: It calculates all the distance between two elementary
	--          curves.
	--          These distances can be maximum or minimum.

uses    Circ2d    from gp,
     	Elips2d   from gp,
     	Hypr2d    from gp,
    	Lin2d     from gp,
     	Parab2d   from gp,
	POnCurv2d from Extrema

raises  InfiniteSolutions from StdFail,
    	NotDone           from StdFail,
    	OutOfRange        from Standard

is
    Create returns ExtElC2d;

    Create (C1,C2: Lin2d; AngTol: Real) returns ExtElC2d;
      	---Purpose: Calculates the distance between two lines.
      	--          AngTol is used to test if the lines are parallel:
      	--          Angle(C1,C2) < AngTol.
    
    Create (C1: Lin2d; C2: Circ2d; Tol: Real) returns ExtElC2d;
        ---Purpose: Calculates the distance between a line and a 
        --          circle.
                  
    Create (C1: Lin2d; C2: Elips2d) returns ExtElC2d;
        ---Purpose: Calculates the distance between a line and an
        --          elipse.
                  
    Create (C1: Lin2d; C2: Hypr2d) returns ExtElC2d;
        ---Purpose: Calculates the distance between a line and a
        --          hyperbola.
                  
    Create (C1: Lin2d; C2: Parab2d) returns ExtElC2d;
        ---Purpose: Calculates the distance between a line and a
        --          parabola.

    Create (C1,C2: Circ2d) returns ExtElC2d;
      	---Purpose: Calculates the distance between two circles.
      	--          The circles can be parallel or identical.
    
    Create (C1: Circ2d; C2: Elips2d) returns ExtElC2d;
        ---Purpose: Calculates the distance between a circle and an
        --          elipse.
                  
    Create (C1: Circ2d; C2: Hypr2d) returns ExtElC2d;
        ---Purpose: Calculates the distance between a circle and a
        --          hyperbola.
                  
    Create (C1: Circ2d; C2: Parab2d) returns ExtElC2d;
        ---Purpose: Calculates the distance between a circle and a
        --          parabola.
                  
    Create (C1,C2: Elips2d) returns ExtElC2d;
      	---Purpose: Calculates the distance between two elipses.
      	--          The elipses can be parallel or identical.
    
    Create (C1: Elips2d; C2: Hypr2d) returns ExtElC2d;
        ---Purpose: Calculates the distance between an elipse and a
        --          hyperbola.
                  
    Create (C1: Elips2d; C2: Parab2d) returns ExtElC2d;
        ---Purpose: Calculates the distance between an elipse and a
        --          parabola.

    Create (C1,C2: Hypr2d) returns ExtElC2d;
      	---Purpose: Calculates the distance between two hyperbolas.
      	--          The hyperbolas can be parallel or identical.
    
    Create (C1: Hypr2d; C2: Parab2d) returns ExtElC2d;
        ---Purpose: Calculates the distance between a hyperbola and a
        --          parabola.

    Create (C1,C2: Parab2d) returns ExtElC2d;
      	---Purpose: Calculates the distance between two parabolas
      	--          The parabolas can be parallel or identical.

    IsDone (me) returns Boolean
    	---Purpose: Returns True if the distances are found.
    	is static;

    IsParallel (me) returns Boolean
    	---Purpose: Returns True if the two curves are parallel.
    	raises  NotDone from StdFail
	    	-- if IsDone(me)=False.
    	is static;

    NbExt (me) returns Integer
    	---Purpose: Returns the number of extremum distances.
    	raises  NotDone from StdFail,
	    	-- if IsDone(me)=False.
    	    	InfiniteSolutions from StdFail
		-- if IsParallel(me)= True.
    	is static;

    SquareDistance (me; N: Integer =1) returns Real
    	---Purpose: Returns the value of the Nth extremum square distance.
    	raises  NotDone from StdFail,
	    	-- if IsDone(me)=False.
    	    	InfiniteSolutions from StdFail,
		-- if IsParallel(me)= True and N > 1.
    	    	OutOfRange from Standard
		-- if N < 1 or N > NbExt(me)
    	is static;

    Points (me; N: Integer; P1,P2: out POnCurv2d)
    	---Purpose: Returns the points of the Nth extremum distance.
    	--          P1 is on the first curve, P2 on the second one.
    	raises  NotDone from StdFail,
	    	-- if IsDone(me)=False.
    	    	InfiniteSolutions from StdFail,
		-- if IsParallel(me)= True.
    	    	OutOfRange from Standard
		-- if N < 1 or N > NbExt(me)
    	is static;

fields
    myDone : Boolean;
    myIsPar: Boolean;
    myNbExt: Integer;
    mySqDist: Real [4];
    myPoint: POnCurv2d from Extrema [4,2];

end ExtElC2d;