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

class CircularArc from IGESGeom  inherits IGESEntity

        ---Purpose: defines IGESCircularArc, Type <100> Form <0>
        --          in package IGESGeom
        --          A circular arc is a connected portion of a parent circle
        --          which consists of more than one point. The definition space
        --          coordinate system is always chosen so that the circular arc
        --          remains in a plane either coincident with or parallel to
        --          the XT, YT plane.

uses

        XY          from gp,
        Dir2d       from gp,
        Dir         from gp,
        Pnt         from gp,
        Pnt2d       from gp

is

        Create returns mutable CircularArc;

        -- Specific Methods pertaining to the class

        Init (me : mutable; aZT : Real; aCenter, aStart, anEnd : XY);
        ---Purpose : This method is used to set the fields of the class
        --           CircularArc
        --       - aZT     : Shift above the Z plane
        --       - aCenter : Center of the circle of which the arc forms a part
        --       - aStart  : Starting point of the circular arc
        --       - anEnd   : Ending point of the circular arc

        Center(me) returns Pnt2d;
        ---Purpose : returns the center of the circle of which arc forms a part

        TransformedCenter(me) returns Pnt;
        ---Purpose : returns the center of the circle of which arc forms a part
        -- after applying Transf. Matrix

        StartPoint(me) returns Pnt2d;
        ---Purpose : returns the start point of the arc

        TransformedStartPoint(me) returns Pnt;
        ---Purpose : returns the start point of the arc after applying Transf. Matrix

        ZPlane(me) returns Real;
        ---Purpose : returns the parallel displacement of the plane containing the
        -- arc from the XT, YT plane

        EndPoint(me) returns Pnt2d;
        ---Purpose : returns the end point of the arc

        TransformedEndPoint(me) returns Pnt;
        ---Purpose : returns the end point of the arc after applying Transf. Matrix

        Radius(me) returns Real;
        ---Purpose : returns the radius of the circle of which arc forms a part

        Angle(me) returns Real;
        ---Purpose : returns the angle subtended by the arc at the center in radians

        Axis(me) returns Dir;
        ---Purpose : Z-Axis of circle (i.e. [0,0,1])

    	TransformedAxis (me) returns Dir;
	---Purpose : Z-Axis after applying Trans. Matrix

        IsClosed(me) returns Boolean;
        ---Purpose : True if StartPoint = EndPoint

fields

--
-- Class    : IGESGeom_CircularArc
--
-- Purpose  : Declaration of variables specific to the definition
--            of the Class CircularArc.
--
-- Reminder : A CircularArc instance is defined by :
--            The center of a circle of which it forms a part
--            the plane in which it lies, the starting point
--            and ending point coordinates

        theZT     : Real;
        theCenter : XY;
        theStart  : XY;
        theEnd    : XY;

end CircularArc;