indexing
	description: "Column of an EV_GRID, containing EV_GRID_ITEMs."
	legal: "See notice at end of class."
	status: "See notice at end of class."
	date: "$Date: 2006-09-12 15:50:35 -0700 (Tue, 12 Sep 2006) $"
	revision: "$Revision: 63522 $"

class interface
	EV_GRID_COLUMN_I

create 
	make (an_interface: like interface)
			-- Create `Current' with interface `an_interface'.
		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 as background of `Current' except where there are items contained that
			-- have a non-`Void' background_color. If `Void', background_color of parent is displayed.

	deselect_actions: EV_NOTIFY_ACTION_SEQUENCE
			-- Actions to be performed when `Current' is deselected.
			-- (from EV_GRID_COLUMN_ACTION_SEQUENCES_I)
		ensure -- from EV_GRID_COLUMN_ACTION_SEQUENCES_I
			result_not_void: Result /= Void

	foreground_color: EV_COLOR
			-- Color displayed for foreground features of `Current' except where there are items contained that
			-- have a non-`Void' foreground_color. If `Void', foreground_color of parent is displayed.

	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)

	index_of_first_item: INTEGER_32
			-- Return the index of the first non `Void' item within `Current'
			-- or 0 if none.
		ensure
			valid_result: Result >= 0 and Result <= count

	is_displayed: BOOLEAN
			-- May `Current' be displayed when its parent is?
			-- Will return False if hide has been called on `Current'.
			-- A column that is_displayed does not necessarily have to be visible on screen at that particular time.

	is_locked: BOOLEAN
			-- Is `Current' locked so that it no longer scrolls?
			-- Note that this could be implemented as a function
			-- "Result := parent_i.locked_columns.item (index) /= Void" but this has not been done
			-- so for performance reasons.

	item (i: INTEGER_32): EV_GRID_ITEM
			-- Item at `i'-th row, Void if none.
		require
			i_positive: i > 0
			i_less_than_count: i <= count
			is_parented: parent /= Void

	locked_position: INTEGER_32
			-- Locked position of `Current' from left edge of viewable area of parent.
			-- `Result' is 0 if not is_locked.
		ensure
			not_locked_implies_result_zero: not is_locked implies Result = 0

	parent: EV_GRID
			-- Grid to which current column belongs.

	pixmap: EV_PIXMAP
			-- Pixmap display on column header to left of title.

	select_actions: EV_NOTIFY_ACTION_SEQUENCE
			-- Actions to be performed when `Current' is selected.
			-- (from EV_GRID_COLUMN_ACTION_SEQUENCES_I)
		ensure -- from EV_GRID_COLUMN_ACTION_SEQUENCES_I
			result_not_void: Result /= Void

	selected_items: ARRAYED_LIST [EV_GRID_ITEM]
			-- All items selected in `Current'.
		require
			is_parented: parent /= Void
		ensure
			result_not_void: Result /= Void

	title: STRING_32
			-- Title of Current column. Empty if none.
		require
			is_parented: parent /= Void
		ensure
			title_not_void: Result /= Void

	virtual_x_position: INTEGER_32
			-- Horizontal offset of `Current' in relation to the
			-- the virtual area of parent grid in pixels.
			-- `Result' is 0 if parent is `Void'.
		ensure
			parent_void_implies_result_zero: parent = Void implies Result = 0

	virtual_x_position_unlocked: INTEGER_32
			-- Horizontal offset of unlocked position of `Current', in relation to the
			-- virtual area of parent grid in pixels.
			-- If not is_locked, then virtual_x_position = `virtual_y_position_unlocked'.
			-- If is_locked then `Result' is the "shadow" position where the column would
			-- be if not locked.
		ensure
			parent_void_implies_result_zero: parent = Void implies Result = 0

	width: INTEGER_32
			-- `Result' is width of `Current'.		
		require
			is_parented: parent /= Void
		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

	count: INTEGER_32
			-- Number of items in current.
		require
			is_parented: parent /= Void
		ensure
			count_not_negative: count >= 0

	index: INTEGER_32
			-- Position of Current in parent.

	internal_is_selected: BOOLEAN

	is_selectable: BOOLEAN
			-- May the object be selected.

	is_selected: BOOLEAN
			-- Is objects state set to selected?

	locked_column: EV_GRID_LOCKED_COLUMN_I
			-- Locked column information for `Current'.
			-- `Void' if not locked.

	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

	disable_select
			-- Deselect `Current' from parent_i.
		require -- from EV_DESELECTABLE_I
			is_selectable: is_selectable
		ensure -- from EV_DESELECTABLE_I
			deselected: not is_selected

	enable_select
			-- Select `Current' in parent_i.
		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
			shown: is_displayed
		ensure
			parent_virtual_y_position_unchanged: old parent.virtual_y_position = parent.virtual_y_position
			to_implement_assertion ("old_is_visible_implies_horizontal_position_not_changed")
			column_visible: virtual_x_position >= parent.virtual_x_position and virtual_x_position + width <= parent.virtual_x_position + (parent.viewable_width).max (width)

	hide
			-- Prevent column from being displayed in parent.
		require
			is_parented: parent /= Void
		ensure
			not_is_displayed: not is_displayed

	lock_at_position (a_position: INTEGER_32)
			-- Ensure is_locked is `True' with the horizontal offset from
			-- the left edge of the viewable area of parent set to `a_position'.
		ensure
			is_locked: is_locked
			locked_position_set: locked_position = a_position

	required_width_of_item_span (start_row, end_row: INTEGER_32): INTEGER_32
			-- Result is greatest `required_width' of all items from
			-- row index `start_row', `end_row'.
		require
			parented: parent /= Void
			valid_rows: start_row >= 1 and end_row <= parent.row_count and start_row <= end_row
		ensure
			result_non_negative: Result >= 0

	show
			-- Allow column to be displayed when parent is.
			-- Does not signify that the column will be visible on screen but that it will be visible within its parent.
		require
			is_parented: parent /= Void
		ensure
			is_displayed: is_displayed

	unlock
			-- Ensure is_locked is `False'.
		ensure
			not_is_locked: not is_locked
	
feature -- Element change

	clear
			-- Remove all items from `Current'.
		require
			is_parented: parent /= Void

	redraw
			-- Force all items within `Current' to be re-drawn when next idle.
		require
			parented: parent /= Void

	remove_pixmap
			-- Remove image displayed on `Current'.
		ensure
			pixmap_removed: pixmap = Void

	set_background_color (a_color: EV_COLOR)
			-- Set background_color with `a_color'.
		require
			is_parented: parent /= Void
		ensure
			background_color_set: background_color = a_color

	set_foreground_color (a_color: EV_COLOR)
			-- Set foreground_color with `a_color'.
		require
			is_parented: parent /= Void
		ensure
			foreground_color_set: foreground_color = a_color

	set_item (i: INTEGER_32; a_item: EV_GRID_ITEM)
			-- Set item at `i'-th row to be `a_item'.
			-- If `a_item' is `Void', the current item (if any) is removed.
		require
			i_positive: i > 0
			is_parented: parent /= Void
			valid_tree_structure_on_insertion: a_item /= Void and parent.is_tree_enabled and parent.row (i).parent_row /= Void implies index >= parent.row (i).parent_row.index_of_first_item
			item_may_be_added_to_tree_node: a_item /= Void and parent.row (i).is_part_of_tree_structure implies parent.row (i).is_index_valid_for_item_setting_if_tree_node (index)
			item_may_be_removed_from_tree_node: a_item = Void and then parent.row (i).is_part_of_tree_structure implies parent.row (i).is_index_valid_for_item_removal_if_tree_node (index)
		ensure
			item_set: item (i) = a_item

	set_pixmap (a_pixmap: EV_PIXMAP)
			-- Display image of `a_pixmap' on `Current' to left of title.
		require
			pixmap_not_void: a_pixmap /= Void
		ensure
			pixmap_set: pixmap = a_pixmap

	set_title (a_title: like title)
			-- a_title_not_void: a_title /= Void.
		require
			is_parented: parent /= Void
		ensure
			title_set: title.is_equal (a_title)

	set_width (a_width: INTEGER_32)
			-- Assign `a_width' to width.
		require
			width_non_negative: a_width >= 0
			is_parented: parent /= Void
		ensure
			width_set: width = a_width
	
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 -- 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
	header_item_not_void: is_initialized implies header_item /= Void
	physical_index_set: parent /= Void implies physical_index >= 0

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

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

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_COLUMN_I