--
-- File:	Visual3d_ContextPick.cdl
-- Created:	Lundi 25 Novembre 1991
-- Author:	NW,JPB,CAL
--
---Copyright:	MatraDatavision 1991,1992,1993
--

class ContextPick from Visual3d

	---Version:

	---Purpose: This class allows the creation and update of
	--	    a pick context for one view of the viewer.
	--	    A context allows the control of different parameters
	--	    before the activation of a pick.
	--
	--	    * the pick aperture.
	--	    * the depth of pick, the number of sub-structures selected.
	--	    * the order of picking, the possibility to traverse
	--	      the pick structures starting from the root
	--	      or the leaves.

	---Keywords: Pick, Context, Aperture, Depth, Order, Structure

	---Warning:
	---References:

uses

	TypeOfOrder     from Visual3d

raises

	ContextPickDefinitionError	from Visual3d

is

	Create
		returns ContextPick from Visual3d;
	---Level: Public
	---Purpose: Creates a context from default values
	--
	--	    Aperture	: 4.0
	--	    Depth	: 10
	--	    Order	: TOO_TOPFIRST

	Create ( Aperture	: Real from Standard;
		 Depth		: Integer from Standard;
		 Order		: TypeOfOrder from Visual3d )
		returns ContextPick from Visual3d
	---Level: Public
	---Purpose: Creates a context with the values defined
	--  Warning: Raises ContextPickDefinitionError if <Depth> or
	--	    <Aperture> is a negative value.
	raises ContextPickDefinitionError;

	-----------------------------------------------------
	-- Category: Methods to modifies the class definition
	-----------------------------------------------------

	SetAperture ( me	: in out;
		      Aperture	: Real from Standard )
	---Level: Public
	---Purpose: Modifies the size of the pick window.
	--  Category: Methods to modifies the class definition
	--  Warning: Raises ContextPickDefinitionError if <Aperture> is
	--	    a negative value.
	raises ContextPickDefinitionError is static;

	SetDepth ( me		: in out;
		   Depth	: Integer from Standard )
	---Level: Public
	---Purpose: Modifies the pick depth a priori.
	--  Category: Methods to modifies the class definition
	--  Warning: Raises ContextPickDefinitionError if <Depth> is
	--	    a negative value.
	raises ContextPickDefinitionError is static;

	SetOrder ( me		: in out;
		   Order	: TypeOfOrder from Visual3d ) is static;
	---Level: Public
	---Purpose: Modifies the order of picking.
	--
	--	    TypeOfOrder : TOO_TOPFIRST
	--			  TOO_BOTTOMFIRST
	--
	---Category: Methods to modifies the class definition

	----------------------------
	-- Category: Inquire methods
	----------------------------

	Aperture ( me )
		returns Real from Standard is static;
	---Level: Public
	---Purpose: Returns the size of the pick window <me>.
	---Category: Inquire methods

	Depth ( me )
		returns Integer from Standard is static;
	---Level: Public
	---Purpose: Returns the effective pick depth of <me>.
	---Category: Inquire methods

	Order ( me )
		returns TypeOfOrder from Visual3d is static;
	---Level: Public
	---Purpose: Returns the order of picking of <me>.
	--
	--	    TypeOfOrder	: TOO_TOPFIRST
	--			  TOO_BOTTOMFIRST
	--
	---Category: Inquire methods

--

fields

--
-- Class	:	Visual3d_ContextPick
--
-- Purpose	:	Declaration of variables specific to
--			pick contexts
--
-- Reminders	:	A pick context is defined by:
--			- the pick aperture
--			- the depth demanded
--			- the order of traversing the structure

	-- aperture of pick
	MyAperture	:	Real from Standard;

	-- depth of pick
	MyDepth		:	Integer from Standard;

	-- order of traversing pick structures
	MyOrder		:	TypeOfOrder from Visual3d;

end ContextPick;