-- File:	Circ2dTanCen.cdl
-- Created:	Tue Oct 20 16:24:19 1992
-- Author:	Remi GILET
--		<reg@sdsun1>
---Copyright:	 Matra Datavision 1992

class Circ2dTanCen from Geom2dGcc

	---Purpose: This class implements the algorithms used to 
	--          create 2d circles tangent to a curve and 
	--          centered on a point. 
	--          The arguments of all construction methods are :
	--             - The qualified element for the tangency constrains 
	--             (QualifiedCurv).
	--             -The center point Pcenter.
	--             - A real Tolerance.
	--          Tolerance is only used in the limits cases.
    	--          For example : 
    	--          We want to create a circle tangent to an EnclosedCurv C1
    	--          with a tolerance Tolerance.
    	--          If we did not used Tolerance it is impossible to 
    	--          find a solution in the the following case : Pcenter is
    	--          outside C1.
    	--          With Tolerance we will give a solution if the distance
    	--          between C1 and Pcenter is lower than or equal Tolerance/2.

-- inherits Entity from Standard

uses QualifiedCurve  from Geom2dGcc,
     Pnt2d           from gp,
     Point           from Geom2d,
     Circ2d          from gp,
     Array1OfInteger from TColStd,
     Array1OfReal    from TColStd,
     Array1OfPnt2d   from TColgp,
     Array1OfCirc2d  from TColgp,
     Boolean         from Standard,
     Position         from GccEnt,
     Array1OfPosition from GccEnt

raises OutOfRange   from Standard,
       BadQualifier from GccEnt,
       NotDone      from StdFail

is

Create( Qualified1 : QualifiedCurve from Geom2dGcc;
        Pcenter    : Point          from Geom2d   ;
        Tolerance  : Real           from Standard ) returns Circ2dTanCen
raises BadQualifier;
    	---Purpose: Constructs one or more 2D circles tangential to the
    	-- curve Qualified1 and centered on the point Pcenter.
    	-- Tolerance is a tolerance criterion used by the algorithm
    	-- to find a solution when, mathematically, the problem
    	-- posed does not have a solution, but where there is
    	-- numeric uncertainty attached to the arguments.
    	-- Tolerance is only used in these algorithms in very
    	-- specific cases where the center of the solution is very
    	-- close to the circle to which it is tangential, and where the
    	-- solution is thus a very small circle.
    	-- Exceptions
    	-- GccEnt_BadQualifier if a qualifier is inconsistent with
    	-- the argument it qualifies (for example, enclosing for a line).


IsDone(me) returns Boolean from Standard
is static;
    	---Purpose: Returns true if the construction algorithm does not fail
    	-- (even if it finds no solution).
    	-- Note: IsDone protects against a failure arising from a
    	-- more internal intersection algorithm, which has reached
    	-- its numeric limits.
    
NbSolutions(me) returns Integer from Standard
raises NotDone
is static;
    	---Purpose: Returns the number of circles, representing solutions
    	-- computed by this algorithm.
    	-- Exceptions
    	-- StdFail_NotDone if the construction fails.
        
ThisSolution(me ; Index : Integer from Standard) returns Circ2d from gp
raises OutOfRange, NotDone
is static;
    	---Purpose: Returns a circle, representing the solution of index
    	-- Index computed by this algorithm.
    	-- Warning
    	-- This indexing simply provides a means of consulting the
    	-- solutions. The index values are not associated with
    	-- these solutions outside the context of the algorithm object.
    	-- Exceptions
    	-- Standard_OutOfRange if Index is less than zero or
    	-- greater than the number of solutions computed by this algorithm.
    	-- StdFail_NotDone if the construction fails

WhichQualifier(me                                  ;
    	       Index   :     Integer  from Standard;
	       Qualif1 : out Position from GccEnt  )
raises OutOfRange, NotDone
is static;
    	---Purpose: Returns the qualifier Qualif1 of the tangency argument
    	-- for the solution of index Index computed by this algorithm.
    	-- The returned qualifier is:
    	-- -   that specified at the start of construction when the
    	--   solutions are defined as enclosed, enclosing or
    	--   outside with respect to the argument, or
    	-- -   that computed during construction (i.e. enclosed,
    	--   enclosing or outside) when the solutions are defined
    	--   as unqualified with respect to the argument.
    	-- Exceptions
    	-- Standard_OutOfRange if Index is less than zero or
    	-- greater than the number of solutions computed by this algorithm.
    	-- StdFail_NotDone if the construction fails. 

Tangency1(me                                     ;
          Index         : Integer   from Standard;
          ParSol,ParArg : out Real  from Standard;
          PntSol        : out Pnt2d from gp      )
raises OutOfRange, NotDone
is static;
    	---Purpose:  Returns informations about the tangency point between the 
    	-- result number Index and the first argument.
    	-- ParSol is the intrinsic parameter of the point PntSol on the solution curv.
    	-- ParArg is the intrinsic parameter of the point PntSol on the argument curv.
    	-- Exceptions
    	-- Standard_OutOfRange if Index is less than zero or
    	-- greater than the number of solutions computed by this algorithm.
    	-- StdFail_NotDone if the construction fails.
        
IsTheSame1(me                            ;
           Index : Integer  from Standard) returns Boolean from Standard
raises OutOfRange, NotDone
is static;
    	---Purpose: Returns true if the solution of index Index and the first
    	-- argument of this algorithm are the same (i.e. there are 2
    	-- identical circles).
    	-- If Rarg is the radius of the first argument, Rsol is the
    	-- radius of the solution and dist is the distance between
    	-- the two centers, we consider the two circles to be
    	-- identical if |Rarg - Rsol| and dist are less than
    	-- or equal to the tolerance criterion given at the time of
    	-- construction of this algorithm.
        --          NotDone is raised if the construction algorithm didn't succeed.
        --          OutOfRange is raised if Index is greater than the 
        --          number of solutions.

fields

    WellDone : Boolean from Standard;
    -- True if the algorithm succeeded.

    NbrSol   : Integer from Standard;
    -- Number of solutions.

    cirsol   : Array1OfCirc2d from TColgp;
    
    qualifier1 : Array1OfPosition from GccEnt;
    -- The qualifiers of the first argument.

    TheSame1 : Array1OfInteger from TColStd;
    -- 1 if the solution and the first argument are the same (2 circles).
    -- if R1 is the radius of the first argument and Rsol the radius 
    -- of the solution and dist the distance between the two centers,
    -- we concider the two circles are identical if R1+dist-Rsol is 
    -- less than Tolerance.
    -- 0 in the other cases.

    pnttg1sol   : Array1OfPnt2d from TColgp;
    -- The tangency point between the solution and the first argument on 
    -- the solution.

    par1sol   : Array1OfReal from TColStd;
    -- The parameter of the tangency point between the solution and the 
    -- first argument on the solution.

    pararg1   : Array1OfReal from TColStd;
    -- The parameter of the tangency point between the solution and the first 
    -- argument on the first argument.


--    CircAna  : Circ2d2TanRad from GccAna;
--    CircGeo  : Circ2d2TanRad from GccGeo;
--    TypeAna  : Boolean;

end Circ2dTanCen;