    indexing
    	description: "Item that can be inserted in a cell of an EV_GRID."
    	legal: "See notice at end of class."
    	status: "See notice at end of class."
    	date: "$Date: 2006-08-16 14:14:38 -0700 (Wed, 16 Aug 2006) $"
    	revision: "$Revision: 62629 $"

    class interface
    	EV_GRID_ITEM_I

    create
    	make (an_interface: like interface)
    			-- Create the widget with `par' as parent.
    		require -- from EV_ANY_I
    			an_interface_not_void: an_interface /= Void
    		ensure -- from EV_ANY_I
    			interface_assigned: interface = an_interface
    			base_make_called: base_make_called

    feature -- Access

    	background_color: EV_COLOR
    			-- Color displayed behind foreground features.

    	column: EV_GRID_COLUMN
    			-- Column to which current item belongs.
    		require
    			is_parented: is_parented
    		ensure
    			column_not_void: Result /= Void

    	foreground_color: EV_COLOR
    			-- Color of foreground features like text.

    	generating_type: STRING_8
    			-- Name of current object's generating type
    			-- (type of which it is a direct instance)
    			-- (from ANY)

    	generator: STRING_8
    			-- Name of current object's generating class
    			-- (base class of the type of which it is a direct instance)
    			-- (from ANY)

    	height: INTEGER_32
    			-- Height of `Current' in pixels.
    		require
    			parented: is_parented
    		ensure
    			result_non_negative: Result >= 0

    	horizontal_indent: INTEGER_32
    			-- Horizontal distance in pixels from left edge of `Current' to left edge of column.
    			-- This may not be set, but the value is determined by the current tree structure
    			-- of parent and row.
    		require
    			parented: parent /= Void
    		ensure
    			not_parent_tree_enabled_implies_result_zero: not parent.is_tree_enabled implies Result = 0
    			parent_tree_enabled_implies_result_greater_or_equal_to_zero: parent.is_tree_enabled implies Result >= 0

    	parent: EV_GRID
    			-- Grid to which `Current' is displayed in.

    	required_width: INTEGER_32
    			-- Width in pixels required to fully display contents, based
    			-- on current settings.
    			-- Note that in some descendents such as EV_GRID_DRAWABLE_ITEM, this
    			-- returns 0. For such items, `set_required_width' is available.

    	row: EV_GRID_ROW
    			-- Row to which current item belongs.
    		require
    			parented: is_parented
    		ensure
    			row_not_void: Result /= Void

    	tooltip: STRING_32
    			-- Tooltip displayed on `Current'.
    			-- If `Result' is `Void' or `is_empty' then no tooltip is displayed.

    	virtual_x_position: INTEGER_32
    			-- Horizontal offset of `Current' in relation to the
    			-- the virtual area of parent grid in pixels.
    		require
    			parented: parent /= Void
    		ensure
    			valid_result: parent /= Void implies Result >= 0 and Result <= parent.virtual_width - column.width + horizontal_indent

    	virtual_y_position: INTEGER_32
    			-- Vertical offset of `Current' in relation to the
    			-- the virtual area of parent grid in pixels.
    		require
    			parented: parent /= Void
    		ensure
    			valid_result_when_parent_row_height_fixed: parent /= Void and then parent.is_row_height_fixed implies Result >= 0 and Result <= parent.virtual_height - parent.row_height
    			valid_result_when_parent_row_height_not_fixed: parent /= Void and then not parent.is_row_height_fixed implies Result >= 0 and Result <= parent.virtual_height - row.height

    	width: INTEGER_32
    			-- Width of `Current' in pixels.
    		require
    			parented: is_parented
    		ensure
    			result_non_negative: Result >= 0

    feature -- Comparison

    	frozen deep_equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void
    			-- or attached to isomorphic object structures?
    			-- (from ANY)
    		ensure -- from ANY
    			shallow_implies_deep: standard_equal (some, other) implies Result
    			both_or_none_void: (some = Void) implies (Result = (other = Void))
    			same_type: (Result and (some /= Void)) implies some.same_type (other)
    			symmetric: Result implies deep_equal (other, some)

    	frozen equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void or attached
    			-- to objects considered equal?
    			-- (from ANY)
    		ensure -- from ANY
    			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.is_equal (other))

    	is_equal (other: like Current): BOOLEAN
    			-- Is `other' attached to an object considered
    			-- equal to current object?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			symmetric: Result implies other.is_equal (Current)
    			consistent: standard_is_equal (other) implies Result

    	frozen standard_equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void or attached to
    			-- field-by-field identical objects of the same type?
    			-- Always uses default object comparison criterion.
    			-- (from ANY)
    		ensure -- from ANY
    			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.standard_is_equal (other))

    	frozen standard_is_equal (other: like Current): BOOLEAN
    			-- Is `other' attached to an object of the same type
    			-- as current object, and field-by-field identical to it?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			same_type: Result implies same_type (other)
    			symmetric: Result implies other.standard_is_equal (Current)

    feature -- Status report

    	conforms_to (other: ANY): BOOLEAN
    			-- Does type of current object conform to type
    			-- of `other' (as per Eiffel: The Language, chapter 13)?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void

    	is_hashable: BOOLEAN
    			-- May current object be hashed?
    			-- (True if it is not its type's default.)
    			-- (from HASHABLE)
    		ensure -- from HASHABLE
    			ok_if_not_default: Result implies (Current /= default)

    	is_parented: BOOLEAN
    			-- Does current item belongs to an EV_GRID?

    	is_selectable: BOOLEAN
    			-- Is `Current' selectable?

    	is_selected: BOOLEAN
    			-- Is `Current' selected?

    	same_type (other: ANY): BOOLEAN
    			-- Is type of current object identical to type of `other'?
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			definition: Result = (conforms_to (other) and other.conforms_to (Current))

    feature -- Status setting

    	activate
    			-- Setup `Current' for user interactive editing.
    		require
    			parented: is_parented

    	deactivate
    			-- Cleanup from previous call to activate.
    		require
    			parented: is_parented

    	disable_select
    			-- Set is_selected `False'.
    		require -- from EV_DESELECTABLE_I
    			is_selectable: is_selectable
    		ensure -- from EV_DESELECTABLE_I
    			deselected: not is_selected

    	enable_select
    			-- Set is_selected `True'.
    		require -- from EV_SELECTABLE_I
    			is_selectable: is_selectable
    		ensure -- from EV_SELECTABLE_I
    			selected: is_selected

    	ensure_visible
    			-- Ensure `Current' is visible in viewable area of parent.
    		require
    			parented: parent /= Void
    		ensure
    			virtual_x_position_not_changed_if_indent_greater_or_equal_to_column_width: old (horizontal_indent > column.width) implies old virtual_x_position = virtual_x_position
    			virtual_x_position_not_changed_if_item_already_visible: old (virtual_x_position >= parent.virtual_x_position) and old (virtual_x_position + width <= parent.virtual_x_position + parent.viewable_width) implies old (virtual_x_position = virtual_x_position)
    			virtual_y_position_not_changed_if_item_already_visible: old (virtual_y_position >= parent.virtual_y_position) and old (virtual_y_position + height <= parent.virtual_y_position + parent.viewable_height) implies old (virtual_y_position = virtual_y_position)
    			row_visible_when_heights_fixed_in_parent: parent.is_row_height_fixed implies row.virtual_y_position >= parent.virtual_y_position and virtual_y_position + parent.row_height <= parent.virtual_y_position + (parent.viewable_height).max (parent.row_height)
    			row_visible_when_heights_not_fixed_in_parent: not parent.is_row_height_fixed implies row.virtual_y_position >= parent.virtual_y_position and virtual_y_position + row.height <= parent.virtual_y_position + (parent.viewable_height).max (row.height)
    			virtual_x_position_visible_if_indent_less_than_row_indent: horizontal_indent < column.width implies virtual_x_position >= parent.virtual_x_position and virtual_x_position + width <= parent.virtual_x_position + (parent.viewable_width).max (width)

    	redraw
    			-- Force `Current' to be re-drawn when next idle.

    feature -- Element change

    	set_background_color (a_color: like background_color)
    			-- Set background_color with `a_color'.

    	set_foreground_color (a_color: like foreground_color)
    			-- Set foreground_color with `a_color'.
    		ensure
    			foreground_color_assigned: foreground_color = a_color

    	set_tooltip (a_tooltip: STRING_GENERAL)
    			-- Assign `a_tooltip' to tooltip.
    			-- pass `Void' to remove the tooltip.
    		ensure
    			tooltip_reset: a_tooltip = Void implies tooltip = Void
    			tooltip_set: a_tooltip /= Void implies ((tooltip.same_type (a_tooltip) implies tooltip = a_tooltip) or (not tooltip.same_type (a_tooltip) implies tooltip.is_equal (a_tooltip)))

    feature -- Duplication

    	copy (other: like Current)
    			-- Update current object using fields of object attached
    			-- to `other', so as to yield equal objects.
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    			type_identity: same_type (other)
    		ensure -- from ANY
    			is_equal: is_equal (other)

    	frozen deep_copy (other: like Current)
    			-- Effect equivalent to that of:
    			--		copy (`other' . deep_twin)
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			deep_equal: deep_equal (Current, other)

    	frozen deep_twin: like Current
    			-- New object structure recursively duplicated from Current.
    			-- (from ANY)
    		ensure -- from ANY
    			deep_equal: deep_equal (Current, Result)

    	frozen standard_copy (other: like Current)
    			-- Copy every field of `other' onto corresponding field
    			-- of current object.
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    			type_identity: same_type (other)
    		ensure -- from ANY
    			is_standard_equal: standard_is_equal (other)

    	frozen standard_twin: like Current
    			-- New object field-by-field identical to `other'.
    			-- Always uses default copying semantics.
    			-- (from ANY)
    		ensure -- from ANY
    			standard_twin_not_void: Result /= Void
    			equal: standard_equal (Result, Current)

    	frozen twin: like Current
    			-- New object equal to `Current'
    			-- twin calls copy; to change copying/twining semantics, redefine copy.
    			-- (from ANY)
    		ensure -- from ANY
    			twin_not_void: Result /= Void
    			is_equal: Result.is_equal (Current)

    feature -- Basic operations

    	frozen default: like Current
    			-- Default value of object's type
    			-- (from ANY)

    	frozen default_pointer: POINTER
    			-- Default value of type `POINTER'
    			-- (Avoid the need to write `p'.default for
    			-- some `p' of type `POINTER'.)
    			-- (from ANY)

    	default_rescue
    			-- Process exception for routines with no Rescue clause.
    			-- (Default: do nothing.)
    			-- (from ANY)

    	frozen do_nothing
    			-- Execute a null action.
    			-- (from ANY)

    feature -- Event handling

    	activate_actions: ACTION_SEQUENCE [TUPLE [EV_POPUP_WINDOW]]
    			-- Actions to be performed to setup `Current' for activation.
    			-- Overrides default setup of activatable items.
    			-- Arguments of TUPLE (with names for clarity):
    			--
    			-- popup_window: EV_WINDOW -- The popup window used to interactively edit `activate_item', window has already been sized and positioned.
    			-- (from EV_GRID_ITEM_ACTION_SEQUENCES_I)

    	deactivate_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when `Current' is deactivated.
    			-- (from EV_GRID_ITEM_ACTION_SEQUENCES_I)
    		ensure -- from EV_GRID_ITEM_ACTION_SEQUENCES_I
    			result_not_void: Result /= Void

    	deselect_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when an item is deselected.
    			-- (from EV_GRID_ITEM_ACTION_SEQUENCES_I)
    		ensure -- from EV_GRID_ITEM_ACTION_SEQUENCES_I
    			result_not_void: Result /= Void

    	drop_actions: EV_PND_ACTION_SEQUENCE
    			-- Actions to be performed when a pebble is dropped here.
    			-- (from EV_GRID_ITEM_ACTION_SEQUENCES_I)
    		ensure -- from EV_GRID_ITEM_ACTION_SEQUENCES_I
    			not_void: Result /= Void

    	pointer_button_press_actions: EV_POINTER_BUTTON_ACTION_SEQUENCE
    			-- Actions to be performed when screen pointer button is pressed.
    			-- (from EV_GRID_ITEM_ACTION_SEQUENCES_I)
    		ensure -- from EV_GRID_ITEM_ACTION_SEQUENCES_I
    			not_void: Result /= Void

    	pointer_button_release_actions: EV_POINTER_BUTTON_ACTION_SEQUENCE
    			-- Actions to be performed when screen pointer button is released.
    			-- (from EV_GRID_ITEM_ACTION_SEQUENCES_I)
    		ensure -- from EV_GRID_ITEM_ACTION_SEQUENCES_I
    			not_void: Result /= Void

    	pointer_double_press_actions: EV_POINTER_BUTTON_ACTION_SEQUENCE
    			-- Actions to be performed when screen pointer is double clicked.
    			-- (from EV_GRID_ITEM_ACTION_SEQUENCES_I)
    		ensure -- from EV_GRID_ITEM_ACTION_SEQUENCES_I
    			not_void: Result /= Void

    	pointer_enter_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when screen pointer enters widget.
    			-- (from EV_GRID_ITEM_ACTION_SEQUENCES_I)
    		ensure -- from EV_GRID_ITEM_ACTION_SEQUENCES_I
    			not_void: Result /= Void

    	pointer_leave_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when screen pointer leaves widget.
    			-- (from EV_GRID_ITEM_ACTION_SEQUENCES_I)
    		ensure -- from EV_GRID_ITEM_ACTION_SEQUENCES_I
    			not_void: Result /= Void

    	pointer_motion_actions: EV_POINTER_MOTION_ACTION_SEQUENCE
    			-- Actions to be performed when screen pointer moves.
    			-- (from EV_GRID_ITEM_ACTION_SEQUENCES_I)
    		ensure -- from EV_GRID_ITEM_ACTION_SEQUENCES_I
    			not_void: Result /= Void

    	select_actions: EV_NOTIFY_ACTION_SEQUENCE
    			-- Actions to be performed when an item is selected.
    			-- (from EV_GRID_ITEM_ACTION_SEQUENCES_I)
    		ensure -- from EV_GRID_ITEM_ACTION_SEQUENCES_I
    			result_not_void: Result /= Void

    feature -- Markers

    	fixme (comment: STRING_8)
    			-- Mark code that has to be "fixed" with `comment'.
    			-- (from REFACTORING_HELPER)
    		require -- from REFACTORING_HELPER
    			comment_not_void: comment /= Void

    	to_implement (comment: STRING_8)
    			-- Mark code that has to be "implemented" with `comment'.
    			-- (from REFACTORING_HELPER)
    		require -- from REFACTORING_HELPER
    			comment_not_void: comment /= Void

    	to_implement_assertion (comment: STRING_8): BOOLEAN
    			-- Mark assertion that has to be "implemented" with `comment'.
    			-- (from REFACTORING_HELPER)
    		require -- from REFACTORING_HELPER
    			comment_not_void: comment /= Void

    feature -- Output

    	io: STD_FILES
    			-- Handle to standard file setup
    			-- (from ANY)

    	out: STRING_8
    			-- New string containing terse printable representation
    			-- of current object
    			-- Was declared in ANY as synonym of tagged_out.
    			-- (from ANY)

    	print (some: ANY)
    			-- Write terse external representation of `some'
    			-- on standard output.
    			-- (from ANY)

    	frozen tagged_out: STRING_8
    			-- New string containing terse printable representation
    			-- of current object
    			-- Was declared in ANY as synonym of out.
    			-- (from ANY)

    feature -- Platform

    	operating_environment: OPERATING_ENVIRONMENT
    			-- Objects available from the operating system
    			-- (from ANY)

    invariant
    	is_parented_implies_parents_set: is_parented implies parent_i /= Void and then column_i /= Void and then row_i /= Void
    	not_is_parented_implies_parents_not_set: not is_parented implies parent_i = Void and then column_i = Void and then row_i = Void
    	hash_code_valid: is_initialized implies ((not is_parented and hash_code = -1) or (is_parented and then hash_code > 0))

    		-- from EV_ANY_I
    	interface_coupled: is_usable implies interface /= Void and then interface.implementation = Current
    	base_make_called: base_make_called

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

    indexing
    	copyright: "Copyright (c) 1984-2006, Eiffel Software and others"
    	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
    	source: "[
    		Eiffel Software
    		356 Storke Road, Goleta, CA 93117 USA
    		Telephone 805-685-1006, Fax 805-685-6869
    		Website http://www.eiffel.com
    		Customer support http://support.eiffel.com
    	]"

    end -- class EV_GRID_ITEM_I