-- File:	Transition.cdl
-- Created:	Fri Apr  3 14:49:41 1992
-- Author:	Laurent BUCHARD
--		<lbr@topsn2>
---Copyright:	 Matra Datavision 1992


class Transition from IntRes2d

inherits Storable from Standard 

    ---Purpose: Definition of    the  type  of   transition    near an
    --          intersection point between  two curves. The transition
    --          is either a "true transition", which means that one of
    --          the curves goes inside or outside  the area defined by
    --          the other curve  near  the intersection, or  a  "touch
    --          transition" which means that the  first curve does not
    --          cross  the  other one,  or an  "undecided" transition,
    --          which means that the curves are superposed.


uses Position  from IntRes2d,
     Situation from IntRes2d,
     TypeTrans from IntRes2d


raises DomainError from Standard

is

    Create

	---Purpose: Empty constructor.
    
    	returns Transition from IntRes2d;


    Create(Tangent: Boolean    from Standard; 
           Pos    : Position   from IntRes2d;
           Type   : TypeTrans  from IntRes2d)
    
	---Purpose: Creates an IN or OUT transition.

	---C++: inline

       	returns Transition from IntRes2d;


    Create(Tangent: Boolean    from Standard; 
           Pos    : Position   from IntRes2d;
           Situ   : Situation  from IntRes2d; 
           Oppos  : Boolean    from Standard)
    
	---Purpose: Creates a TOUCH transition.

	---C++: inline
    
    	returns Transition from IntRes2d;


    Create(Pos: Position from IntRes2d)
    
	---Purpose: Creates an UNDECIDED transition.

	---C++: inline

       	returns Transition from IntRes2d;


    SetValue(me: in out; Tangent: Boolean   from Standard; 
                         Pos    : Position  from IntRes2d;
                         Type   : TypeTrans from IntRes2d)

	---Purpose: Sets the values of an IN or OUT transition.

	---C++: inline

    	is static;


    SetValue(me: in out; Tangent: Boolean    from Standard; 
    	                 Pos    : Position   from IntRes2d;
                         Situ   : Situation  from IntRes2d;
                         Oppos  : Boolean    from Standard)

	---Purpose: Sets the values of a TOUCH transition.

	---C++: inline
    
    	is static;


    SetValue(me: in out; Pos: Position from IntRes2d)

	---Purpose: Sets the values of an UNDECIDED transition.

	---C++: inline

    	is static;


    SetPosition(me: in out; Pos: Position from IntRes2d)
    
	---Purpose: Sets the value of the position.

	---C++: inline

    	is static;


    PositionOnCurve(me)

    	---Purpose: Indicates if the  intersection is at the beginning
    	--          (IntRes2d_Head),  at the end (IntRes2d_End), or in
    	--          the middle (IntRes2d_Middle) of the curve.

   	---C++: inline
       
    	returns Position from IntRes2d
	is static;


    TransitionType(me)
    
	---Purpose: Returns the type of transition at the intersection.
	--          It may be IN or OUT or TOUCH, or UNDECIDED if the
	--          two first derivatives are not enough to give
	--          the tangent to one of the two curves.

	---C++: inline
    
    	returns TypeTrans from IntRes2d
	is static;


    IsTangent(me)
    
	---Purpose: Returns TRUE when the 2 curves are tangent at the
	--          intersection point.
	--          Theexception DomainError is raised if the type of
	--          transition is UNDECIDED.

	---C++: inline

    	returns Boolean     from Standard
	raises  DomainError from Standard
	is static;


    Situation(me)
    
    	---Purpose: returns a significant value if TransitionType returns
    	--          TOUCH. In this case, the function returns :
    	--          INSIDE when the curve remains inside the other one,
    	--          OUTSIDE when it remains outside the other one,
    	--          UNKNOWN when the calculus, based on the second derivatives
    	--          cannot give the result.
    	--          If TransitionType returns IN or OUT or UNDECIDED, the
    	--          exception DomainError is raised.

	---C++: inline

    	returns Situation   from IntRes2d
    	raises  DomainError from Standard
	is static;


    IsOpposite(me)
    
    	---Purpose: returns a  significant value   if   TransitionType
    	--          returns TOUCH. In this  case, the function returns
    	--          true   when  the  2   curves   locally define  two
    	--          different  parts of the  space.  If TransitionType
    	--          returns  IN or   OUT or UNDECIDED,  the  exception
    	--          DomainError is raised.

	---C++: inline

    	returns Boolean     from Standard
    	raises  DomainError from Standard
	is static;


fields

    tangent     : Boolean   from Standard;
    posit       : Position  from IntRes2d;
    typetra     : TypeTrans from IntRes2d;
    situat      : Situation from IntRes2d;
    oppos       : Boolean   from Standard;
    
end Transition;