--
-- File    :  BSplineCurve.cdl
-- Created :  Sat 9 Jan 1993
-- Author  :  Kiran
--
---Copyright : MATRA-DATAVISION  1993
--

class BSplineCurve from IGESGeom  inherits IGESEntity

        ---Purpose : defines IGESBSplineCurve, Type <126> Form <0-5>
        --           in package IGESGeom
        --           A parametric equation obtained by dividing two summations
        --           involving weights (which are real numbers), the control
        --           points, and B-Spline basis functions

uses

        Pnt           from gp,
        XYZ           from gp,
        HArray1OfReal from TColStd,
        HArray1OfXYZ  from TColgp

raises DimensionMismatch, OutOfRange

is

        Create returns mutable BSplineCurve;

        -- Specific Methods pertaining to the class

        Init (me           : mutable;
              anIndex      : Integer;
              aDegree      : Integer;
              aPlanar      : Boolean;
              aClosed      : Boolean;
              aPolynom     : Boolean;
              aPeriodic    : Boolean;
              allKnots     : HArray1OfReal;
              allWeights   : HArray1OfReal;
              allPoles     : HArray1OfXYZ;
              aUmin, aUmax : Real;
              aNorm        : XYZ)
        raises DimensionMismatch;
        ---Purpose : This method is used to set the fields of the class
        --           BSplineCurve. Beware about indexation of arrays
        --       - anIndex      : Upper index of the sum
        --       - aDegree      : Degree of basis functions
        --       - aPlanar      : 0 = nonplanar curve, 1 = planar curve
        --       - aClosed      : 0 = open curve, 1 = closed curve
        --       - aPolynom     : 0 = rational, 1 = polynomial
        --       - aPeriodic    : 0 = nonperiodic, 1 = periodic
        --       - allKnots     : Knot sequence values [-Degree,Index+1]
        --       - allWeights   : Array of weights     [0,Index]
        --       - allPoles     : X, Y, Z coordinates of all control points
        --                                             [0,Index]
        --       - aUmin, aUmax : Starting and ending parameter values
        --       - aNorm        : Unit normal (if the curve is planar)
        -- raises exception if allWeights & allPoles are not of same size.

    	SetFormNumber (me : mutable; form : Integer) raises OutOfRange;
	---Purpose : Changes FormNumber (indicates the Shape of the Curve)
	--           Error if not in range [0-5]


        UpperIndex(me) returns Integer;
        ---Purpose : returns the upper index of the sum (see Knots,Poles)

        Degree(me) returns Integer;
        ---Purpose : returns the degree of basis functions

        IsPlanar(me) returns Boolean;
        ---Purpose : returns True if the curve is Planar, False if non-planar

        IsClosed(me) returns Boolean;
        ---Purpose : returns True if the curve is closed, False if open

        IsPolynomial(me; flag : Boolean = Standard_False) returns Boolean;
        ---Purpose : returns True if the curve is polynomial, False if rational
        --           <flag> False (D) : computed from the list of weights
        --             (all must be equal)
        --           <flag> True : as recorded

        IsPeriodic(me) returns Boolean;
        ---Purpose : returns True if the curve is periodic, False otherwise

        NbKnots(me) returns Integer;
        ---Purpose : returns the number of knots (i.e. Degree + UpperIndex + 2)

        Knot(me; anIndex : Integer) returns Real
        raises OutOfRange;
        ---Purpose : returns the knot referred to by anIndex,
        --           inside the range [-Degree,UpperIndex+1]
        -- raises exception if
        --      anIndex < -Degree() or anIndex > (NbKnots() - Degree())
        -- Note : Knots are numbered from -Degree (not from 1)

        NbPoles(me) returns Integer;
        ---Purpose : returns number of poles (i.e. UpperIndex + 1)

        Weight(me; anIndex : Integer) returns Real
        raises OutOfRange;
        ---Purpose : returns the weight referred to by anIndex, in [0,UpperIndex]
        -- raises exception if anIndex < 0 or anIndex > UpperIndex()

        Pole(me; anIndex : Integer) returns Pnt
        raises OutOfRange;
        ---Purpose : returns the pole referred to by anIndex, in [0,UpperIndex]
        -- raises exception if anIndex < 0 or anIndex > UpperIndex()

        TransformedPole(me; anIndex : Integer) returns Pnt
        raises OutOfRange;
        ---Purpose : returns the anIndex'th pole after applying Transf. Matrix
        -- raises exception if an Index < 0 or an Index > UpperIndex()

        UMin(me) returns Real;
        ---Purpose : returns starting parameter value

        UMax(me) returns Real;
        ---Purpose : returns ending parameter value

        Normal(me) returns XYZ;
        ---Purpose : if the curve is nonplanar then (0, 0, 0) is returned

fields

--
-- Class    : IGESGeom_BSplineCurve
--
-- Purpose  : Declaration of variables specific to the definition
--            of the Class BSplineCurve.
--
-- Reminder : A BSplineCurve instance is defined by :
--            A parametric equation obtained by dividing two summations
--            involving weights (which are real numbers), the control
--            points, and B-Spline basis functions

        theIndex     : Integer;           -- Upper index of the sum
        theDegree    : Integer;
        isPlanar     : Boolean;
        isClosed     : Boolean;
        isPolynomial : Boolean;
        isPeriodic   : Boolean;
        theKnots     : HArray1OfReal;
        theWeights   : HArray1OfReal;
        thePoles     : HArray1OfXYZ;
        theUmin      : Real;              -- Starting parameter value
        theUmax      : Real;              -- Ending parameter value
        theNorm      : XYZ;

end BSplineCurve;