--
-- File      :  Plane.cdl
-- Created   :  Sat 9 Jan 1993
-- Author    : CKY / Contract Toubro-Larsen ( Kiran )
--
---Copyright : MATRA-DATAVISION  1993
--

class Plane from IGESGeom  inherits IGESEntity

        ---Purpose: defines IGESPlane, Type <108> Form <-1,0,1>
        --          in package IGESGeom
        --          A plane entity can be used to represent unbounded plane,
        --          as well as bounded portion of a plane. In either of the
        --          above cases the plane is defined within definition space
        --          by means of coefficients A, B, C, D where at least one of
        --          A, B, C is non-zero and  A * XT + B * YT + C * ZT = D

uses

        Pnt         from gp,
        XYZ         from gp

is

        Create returns mutable Plane;

        -- Specific Methods pertaining to the class

        Init(me         : mutable;
             A, B, C, D : Real; 
             aCurve     : IGESEntity;
             attach     : XYZ; 
             aSize      : Real);
        -- This method is used to set the fields of the
        -- class Plane
        --       - A, B, C, D : Coefficients in the planar equation
        --       - aCurve     : Bounding curve of the plane, if any
        --       - attach     : Location of the display symbol if one exists,
        --                      else (0, 0, 0)
        --       - aSize      : Size of the display symbol if one exists else 0

    	SetFormNumber (me : mutable; form : Integer);
	---Purpose : Changes FormNumber (indicates the Type of Bound :
	--           0 no Bound, 1 (External) Bound, -1 Hole)
	--           Remark that Init keeps this Value and must be consistent :
	--           aCurve Null if FormNumber = 0, Non-Null else
	--           Error if not in ranges [0-1] or [10-12]


        Equation(me; A, B, C, D : out Real);
        -- returns the basic equation describing the plane
        -- A, B, C, D are the coefficients of plane.

        TransformedEquation(me; A, B, C, D : out Real);
        -- returns basic equation describing plane after applying Location()

        HasBoundingCurve(me) returns Boolean;
        ---Purpose : returns True if there exists a bounding curve

        HasBoundingCurveHole(me) returns Boolean;
        ---Purpose : returns True if bounding curve exists and bounded portion is negative

        BoundingCurve(me) returns IGESEntity;
        ---Purpose : returns Optional Bounding Curve, can be positive (normal clipping)
        -- or negative (hole) according to Form Number

        HasSymbolAttach(me) returns Boolean;
        ---Purpose : returns True if SymbolSize() > 0, False if SymbolSize() = 0

        SymbolAttach(me) returns Pnt;
        ---Purpose : returns (X, Y, Z) if symbol exists else returns (0, 0, 0)

        TransformedSymbolAttach(me) returns Pnt;
        ---Purpose : returns (X, Y, Z) if symbol exists after applying Transf. Matrix
        -- else returns (0, 0, 0)

        SymbolSize(me) returns Real;
        ---Purpose : Size of optional display symbol

fields

--
-- Class    : IGESGeom_Plane
--
-- Purpose  : Declaration of variables specific to the definition
--            of the Class Plane.
--
-- Reminder : A Plane instance is defined by :
--            The plane cooefficients, the bounding curve if any,
--            the size of an optional display symbol.

        theA       : Real;
        theB       : Real;
        theC       : Real;
        theD       : Real;
        theCurve   : IGESEntity;
        theAttach  : XYZ;            -- The display symbol
        theSize    : Real;

end Plane;