-- File:	GeomFill_TgtField.cdl
-- Created:	Mon Dec  4 11:11:31 1995
-- Author:	Laurent BOURESCHE
--		<lbo@phylox>
---Copyright:	 Matra Datavision 1995


deferred class TgtField from GeomFill inherits TShared from MMgt

	---Purpose: Root class defining the methods we need to make an
	--          algorithmic tangents field.

uses
    Vec from gp,
    BSpline from Law

is

    IsScalable(me) returns Boolean from Standard is virtual;
    Scale(me : mutable; Func : BSpline from Law) is virtual;

    Value(me; W : Real from Standard)
    returns Vec from gp
    ---Purpose: Computes  the value  of the    field of tangency    at
    --          parameter W.
    is deferred;

    D1(me; W : Real from Standard)
    returns Vec from gp
    ---Purpose: Computes the  derivative of  the field of  tangency at
    --          parameter W.
    is deferred;

    D1(me; W : Real from Standard; V, DV : out Vec from gp)
    ---Purpose: Computes the value and the  derivative of the field of
    --          tangency at parameter W.
    is deferred;

end TgtField;