-- File:	IGESSelect_SplineToBSpline.cdl
-- Created:	Thu Jun  2 18:18:34 1994
-- Author:	Christian CAILLET
--		<cky@bravox>
---Copyright:	 Matra Datavision 1994


class SplineToBSpline  from IGESSelect  inherits Transformer

    ---Purpose : This type of Transformer allows to convert Spline Curves (IGES
    --           type 112) and Surfaces (IGES Type 126) to BSpline Curves (IGES
    --           type 114) and Surfac (IGES Type 128). All other entities are
    --           rebuilt as identical but on the basis of this conversion.
    --           
    --           It also gives an option to, either convert as such (i.e. each
    --           starting part of the spline becomes a segment of the bspline,
    --           with continuity C0 between segments), or try to increase
    --           continuity as far as possible to C1 or to C2.
    --           
    --           It does nothing if the starting model contains no Spline
    --           Curve (IGES Type 112) or Surface (IGES Type 126). Else,
    --           converting and rebuilding implies copying of entities.

uses AsciiString from TCollection,
     CheckIterator, Graph, CopyControl, Protocol from Interface, InterfaceModel

is

    Create (tryC2 : Boolean) returns mutable SplineToBSpline;
    ---Purpose : Creates a Transformer SplineToBSpline. If <tryC2> is True,
    --           it will in addition try to upgrade continuity up to C2.

    OptionTryC2 (me) returns Boolean;
    ---Purpose : Returns the option TryC2 given at creation time

    Perform (me : mutable; G : Graph; protocol : Protocol from Interface;
    	     checks : in out CheckIterator;
    	     newmod : out mutable InterfaceModel)  returns Boolean;
    ---Purpose : Performs the transformation, if there is at least one Spline
    --           Curve (112) or Surface (126). Does nothing if there is none.

    Updated (me; entfrom : Transient; entto : out mutable Transient)
    	returns Boolean;
    ---Purpose : Returns the transformed entities.
    --           If original data contained no Spline Curve or Surface,
    --           the result is identity : <entto> = <entfrom>
    --           Else, the copied counterpart is returned : for a Spline Curve
    --           or Surface, it is a converted BSpline Curve or Surface. Else,
    --           it is the result of general service Copy (rebuilt as necessary
    --           by BSPlines replacing Splines).

    Label (me) returns AsciiString from TCollection;
    ---Purpose : Returns a text which defines the way a Transformer works :
    --           "Conversion Spline to BSpline" and as opted,
    --           " trying to upgrade continuity"

fields

    thetryc2 : Boolean;
    thefound : Boolean;        -- at least one Spline found and converted
    themap   : CopyControl;

end SplineToBSpline;