indexing
	description: "Null pen."
	status: "See notice at end of class."
	date: "$Date$"
	revision: "$Revision$"

class interface
	WEL_NULL_PEN

create 

	make
			-- Make a gdi stock object identified by stock_id.
			-- (from WEL_GDI_STOCK)
		ensure -- from WEL_GDI_STOCK
			exists: exists
			shared: shared

feature -- Access

	color: WEL_COLOR_REF
			-- Pen color
			-- (from WEL_PEN)
		require -- from WEL_PEN
			exists: exists
		ensure -- from WEL_PEN
			result_not_void: Result /= void

	gdi_objects_count: INTEGER
			-- Number of GDI object currently allocated by the
			-- program.
			--
			-- Note: debug option "WEL_GDI_COUNT" should be enabled, otherwise
			-- this function will return zero.
			-- (from WEL_GDI_ANY)

	item: POINTER
			-- Generic Windows handle or structure pointer.
			-- Can be a HWND, HICON, RECT *, WNDCLASS *, etc...
			-- (from WEL_ANY)

	log_pen: WEL_LOG_PEN
			-- Log pen structure associated to Current
			-- (from WEL_PEN)
		require -- from WEL_PEN
			exists: exists
		ensure -- from WEL_PEN
			result_not_void: Result /= void

	style: INTEGER
			-- Pen style
			-- (from WEL_PEN)
		require -- from WEL_PEN
			exists: exists
		ensure -- from WEL_PEN
			valid_result: valid_pen_style_constant (Result)

	width: INTEGER
			-- Pen width
			-- (from WEL_PEN)
		require -- from WEL_PEN
			exists: exists
		ensure -- from WEL_PEN
			positive_result: Result >= 0
	
feature -- Status report

	exists: BOOLEAN
			-- Does the item exist?
			-- (from WEL_ANY)
		ensure -- from WEL_ANY
			Result = (item /= default_pointer)

	shared: BOOLEAN
			-- Is item shared by another object?
			-- If False (by default), item will
			-- be destroyed by destroy_item.
			-- If True, item will not be destroyed.
			-- (from WEL_ANY)
	
feature  -- Status report

	valid_pen_style_constant (c: INTEGER): BOOLEAN
			-- Is c a valid pen style constant?
			-- (from WEL_PS_CONSTANTS)
	
feature -- Status setting

	set_shared
			-- Set shared to True.
			-- (from WEL_ANY)
		ensure -- from WEL_ANY
			shared: shared

	set_unshared
			-- Set shared to False.
			-- (from WEL_ANY)
		ensure -- from WEL_ANY
			unshared: not shared
	
feature -- Element change

	set_item (an_item: POINTER)
			-- Set item with an_item
			-- (from WEL_ANY)
		ensure -- from WEL_ANY
			item_set: item = an_item
	
feature -- Removal

	delete
			-- Destroy the inner structure of Current.
			--
			-- Call this function when Current is no more needed
			-- (from WEL_REFERENCE_TRACKABLE)
		require -- from WEL_REFERENCE_TRACKABLE
			reference_not_tracked: not reference_tracked
		ensure -- from WEL_REFERENCE_TRACKABLE
			destroyed: not shared implies not exists

	dispose
			-- Destroy the inner structure of Current.
			--
			-- This function is called by the GC when the
			-- object is collected, the developer should
			-- use delete.
			-- (from WEL_REFERENCE_TRACKABLE)
	
feature -- Conversion

	to_integer: INTEGER
			-- Converts item to an integer.
			-- (from WEL_ANY)
		ensure -- from WEL_ANY
			Result = cwel_pointer_to_integer (item)
	
feature -- Status Report

	reference_tracked: BOOLEAN
			-- Are the number references of Current tracked?
			-- (from WEL_REFERENCE_TRACKABLE)

	references_count: INTEGER
			-- Number of object referring this object.
			-- (from WEL_REFERENCE_TRACKABLE)
	
feature -- Status Setting

	decrement_reference
			-- Decrement the number of references to this object.
			--
			-- When the number of references reach zero,
			-- delete is called if the object is not protected.
			-- (from WEL_REFERENCE_TRACKABLE)
		require -- from WEL_REFERENCE_TRACKABLE
			exists: exists
			tracking_references_started: reference_tracked

	enable_reference_tracking
			-- Set references_tracked to True.
			--
			-- (from WEL_REFERENCE_TRACKABLE)
		require -- from WEL_REFERENCE_TRACKABLE
			exists: exists
			tracking_reference_not_started: not reference_tracked

	increment_reference
			-- Increment the number of references to this object.
			-- (from WEL_REFERENCE_TRACKABLE)
		require -- from WEL_REFERENCE_TRACKABLE
			exists: exists
			tracking_references_started: reference_tracked

	object_id: INTEGER
			-- Runtime Id of Current.
			-- (from WEL_REFERENCE_TRACKABLE)
	
invariant

		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

end -- class WEL_NULL_PEN