-- File:	AIS_SignatureFilter.cdl
-- Created:	Tue Mar  4 17:29:20 1997
-- Author:	Robert COUBLANC
--		<rob@robox.paris1.matra-dtv.fr>
---Copyright:	 Matra Datavision 1997


class SignatureFilter from AIS inherits TypeFilter from AIS

	---Purpose: Selects Interactive Objects through their signatures
    	-- and types. The signature provides an
    	-- additional   characterization of an object's type, and
    	-- takes the form of an index. The filter questions each
    	-- Interactive Object in local context to determine
    	-- whether it has an non-null owner, and if so, whether
    	-- it has the desired signature. If the object returns true
    	-- in each case, it is kept. If not, it is rejected.
    	-- By default, the   interactive object has a None   type
    	-- and a signature of 0. If you want to give a particular
    	-- type and signature to your Interactive Object, you
    	-- must redefine two virtual methods:   Type and Signature.
    	-- This filter is only used in an open local contexts.
    	-- In the Collector viewer, you can only locate
    	-- Interactive Objects which answer positively to the
    	-- positioned filters when a local context is open.
    	-- Warning
    	-- Some signatures have already been used by standard
    	-- objects delivered in AIS. These include:
    	-- -   signature 0 - Shape
    	-- -   signature 1 - Point
    	-- -   signature 2 - Axis
    	-- -   signature 3 - Trihedron
    	-- -   signature 4 - PlaneTrihedron
    	-- -   signature 5 - Line
    	-- -   signature 6 - Circle
    	-- -   signature 7 - Plane
        
        
        
uses
    
    KindOfInteractive from AIS,
    EntityOwner from SelectMgr

is

    Create(aGivenKind      : KindOfInteractive from AIS;
           aGivenSignature : Integer from Standard)
    returns mutable SignatureFilter from AIS;
    	--- Purpose: Initializes the signature filter, adding the signature
    	-- specification, aGivenSignature, to that for type,
    	-- aGivenKind, in AIS_TypeFilter.
        
    IsOk (me;anobj : EntityOwner from SelectMgr)
    returns Boolean from Standard is redefined static;
    	---Purpose: Returns False if the transient is not an AIS_InteractiveObject.
    	--          Returns False if the signature of InteractiveObject
    	--          is not the same as the stored one in the filter...
              

fields
    mySig  : Integer           from Standard;
end SignatureFilter;