-- File:	GeomAPI_Interpolate.cdl
-- Created:	Thu Aug 18 15:50:24 1994
-- Author:	Laurent PAINNOT
--		<lpa@metrox>
---Copyright:	 Matra Datavision 1994


class Interpolate from Geom2dAPI

    	---Purpose: This  class  is  used  to  interpolate a  BsplineCurve
    	-- passing   through  an  array  of  points,  with  a  C2
    	-- Continuity if tangency is not requested at the point.
    	-- If tangency is requested at the point the continuity will
    	-- be C1.  If Perodicity is requested the curve will be closed
    	-- and the junction will be the first point given. The curve will than be only C1
    	-- The curve is defined by a table of points through which it passes, and if required
    	-- by a parallel table of reals which gives the value of the parameter of each point through
    	--  which the resulting BSpline curve passes, and by vectors tangential to these points.
    	-- An Interpolate object provides a framework for: defining the constraints of the BSpline curve,
    	-- -   implementing the interpolation algorithm, and consulting the results.
           
    --          



uses

    Vec2d              from gp,
    Array1OfPnt2d      from TColgp,
    HArray1OfPnt2d     from TColgp,
    Array1OfVec2d      from TColgp,
    HArray1OfBoolean   from TColStd,
    HArray1OfReal      from TColStd,
    HArray1OfVec2d     from TColgp,
    BSplineCurve       from Geom2d

raises
    NotDone           from StdFail,
    ConstructionError from Standard
is
    
    Create(Points       : HArray1OfPnt2d from TColgp   ;
    	   PeriodicFlag : Boolean      from Standard ;
    	   Tolerance    : Real)
    	---Purpose: Tolerance is to check if the points are not too close to one an other
    	-- It is also used to check if the tangent vector is not too small.
    	-- There should be at least 2 points
    	-- if PeriodicFlag is True then the curve will be periodic.

    returns Interpolate from Geom2dAPI
    
    raises ConstructionError from Standard ;	   

    Create(Points       : HArray1OfPnt2d  from TColgp ;
    	   Parameters   : HArray1OfReal from TColStd;
	   PeriodicFlag : Boolean       from Standard;
    	   Tolerance    : Real) 
    	---Purpose: if PeriodicFlag is True then the curve will be periodic
    	--  Warning: 
    	--  There should be as many parameters as there are points
    	--  except if PeriodicFlag is True : then there should be one more
    	--  parameter to close the curve
    
    returns Interpolate from Geom2dAPI
    
    raises ConstructionError from Standard ;	
    Load(me : in out;
         InitialTangent : Vec2d from gp;
	 FinalTangent   : Vec2d from gp) 
    	---Purpose: Assigns this constrained BSpline curve to be
    	-- tangential to vectors InitialTangent and FinalTangent
    	--   at its first and last points respectively (i.e.
    	--   the first and last points of the table of
    	--   points through which the curve passes, as
    	--   defined at the time of initialization).
     
    is static ;
    
    Load(me : in out;
         Tangents     : Array1OfVec2d     from TColgp ;
         TangentFlags : HArray1OfBoolean from TColStd)
    is static; 
    	---Purpose:  Assigns this constrained BSpline curve to be
    	-- tangential to vectors defined in the table Tangents,
    	--   which is parallel to the table of points
    	--   through which the curve passes, as
    	--   defined at the time of initialization. Vectors
    	--   in the table Tangents are defined only if
    	--   the flag given in the parallel table
    	--   TangentFlags is true: only these vectors
    	--   are set as tangency constraints.
             
 
    ClearTangents(me : in out) ;
    	---Purpose: Clears all tangency constraints on this
    	-- constrained BSpline curve (as initialized by the function Load).
        
    Perform(me : in out) ;
    	---Purpose: Computes the constrained BSpline curve. Use the function IsDone to verify that the
    	-- computation is successful, and then the function Curve to obtain the result.
        
    Curve(me) 
    returns BSplineCurve from Geom2d
	---C++: return const &
	---C++: alias "Standard_EXPORT operator Handle(Geom2d_BSplineCurve)() const;"
    	---Purpose: Returns the computed BSpline curve. Raises  StdFail_NotDone if the interpolation fails.
    raises
    	NotDone from StdFail
    is static;
	    

    IsDone(me)
    returns Boolean from Standard
    is static;
    	--- Purpose: Returns true if the constrained BSpline curve is successfully constructed.
    	-- Note: in this case, the result is given by the function Curve. 
    
    PerformNonPeriodic(me : in out) 
    	---Purpose: Interpolates in a non periodic fashion   
    is private ;
    
    PerformPeriodic(me : in out) 
    	---Purpose: Interpolates in a C1 periodic fashion
       
    is private ;
	    
fields

    myTolerance      : Real             from Standard ;
    -- the 3D tolerance to check for degenerate points
    myPoints         : HArray1OfPnt2d     from TColgp   ;
    -- the points to interpolates
    myIsDone         : Boolean          from Standard ;
    -- the algorithm did complete OK if Standard_True 
    myCurve          : BSplineCurve     from Geom2d     ;
    -- the interpolated curve
    myTangents       : HArray1OfVec2d     from TColgp   ;
    -- the tangents only defined at slot i if 
    -- myTangenFlags->Value(i) is Standard_True 
    myTangentFlags   : HArray1OfBoolean from TColStd  ;
    -- the flags defining the tangents
    myParameters     : HArray1OfReal    from TColStd  ;
    -- the parameters used for the cubic interpolation
    myPeriodic       : Boolean          from Standard ;
    -- if Standard_True the curve will be periodic
    myTangentRequest : Boolean          from Standard ;
    -- Tangents are given if True False otherwise

end Interpolate;