indexing
	description: "[
								A EV_FIGURE_GROUP is an ARRAYED_LIST of EV_FIGURE.
								Since EV_FIGURE_GROUP is also an EV_FIGURE (composite pattern) you
								can rotate, scale and change the position of an EV_FIGURE_GROUP.
								All elements in the group are rotated around the center
								of the EV_FIGURE_GROUP. A EV_FIGURE can only be grouped
								in one group at the same time.
		
	]"
	legal: "See notice at end of class."
	status: "See notice at end of class."
	date: "$Date: 2006-01-22 18:25:44 -0800 (Sun, 22 Jan 2006) $"
	revision: "$Revision: 56675 $"

class interface
	EV_MODEL_GROUP

create 
	default_create
			-- Create an empty EV_MODEL_GROUP.
		require -- from  ANY
			True
		ensure then
			is_grouped: is_grouped
			not_is_in_group: not is_in_group

	make_with_point (a_point: EV_COORDINATE)
			-- Create on `a_point'.
			-- (from EV_MODEL_SINGLE_POINTED)
		require -- from EV_MODEL_SINGLE_POINTED
			a_point_not_void: a_point /= Void

	make_with_position (a_point_x, a_point_y: INTEGER_32)
			-- Create on (`a_point_x', `a_point_y')
			-- (from EV_MODEL_SINGLE_POINTED)


create {EV_MODEL_GROUP}
	make_filled (n: INTEGER_32)
			-- Allocate list with `n' items.
			-- (`n' may be zero for empty list.)
			-- This list will be full.
			-- (from ARRAYED_LIST)
		require -- from ARRAYED_LIST
			valid_number_of_items: n >= 0
		ensure -- from ARRAYED_LIST
			correct_position: before
			filled: full

feature -- Initialization

	list_make (n: INTEGER_32)
			-- Allocate list with `n' items.
			-- (`n' may be zero for empty list.)
			-- (from ARRAYED_LIST)
		require -- from ARRAYED_LIST
			valid_number_of_items: n >= 0
		ensure -- from ARRAYED_LIST
			correct_position: before
			is_empty: is_empty

	make_filled (n: INTEGER_32)
			-- Allocate list with `n' items.
			-- (`n' may be zero for empty list.)
			-- This list will be full.
			-- (from ARRAYED_LIST)
		require -- from ARRAYED_LIST
			valid_number_of_items: n >= 0
		ensure -- from ARRAYED_LIST
			correct_position: before
			filled: full
	
feature -- Access

	angle: REAL_64
			-- `Current' has to be rotated around (x,y) for -angle
			-- to be in upright position.
		require -- from  EV_MODEL
			True
		ensure then
			result_equal_current_angle: Result = current_angle

	cursor: ARRAYED_LIST_CURSOR
			-- Current cursor position
			-- (from ARRAYED_LIST)
		ensure -- from CURSOR_STRUCTURE
			cursor_not_void: Result /= Void

	deep_elements: LIST [EV_MODEL]
			-- All elements in `Current' and in its subgroups.
		ensure
			result_not_void: Result /= Void

	first: like item
			-- Item at first position
			-- (from ARRAYED_LIST)
		require -- from CHAIN
			not_empty: not is_empty

	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)

	group: EV_MODEL_GROUP
			-- The group `Current' is part of. Void if `Current' is 
			-- not part of a group.
			-- (from EV_MODEL)

	i_th alias "[]" (i: INTEGER_32): like item assign put_i_th
			-- Item at `i'-th position
			-- Was declared in ARRAYED_LIST as synonym of infix "@".
			-- (from ARRAYED_LIST)
		require -- from TABLE
			valid_key: valid_index (i)

	id: INTEGER_32
			-- Unique id.
			-- (from EV_MODEL)
		ensure -- from HASHABLE
			good_hash_value: Result >= 0

	frozen id_object (an_id: INTEGER_32): IDENTIFIED
			-- Object associated with `an_id' (void if no such object)
			-- (from IDENTIFIED)
		ensure -- from IDENTIFIED
			consistent: Result = Void or else Result.object_id = an_id

	index: INTEGER_32
			-- Index of item, if valid.
			-- (from ARRAYED_LIST)

	index_of (v: like item; i: INTEGER_32): INTEGER_32
			-- Index of `i'-th occurrence of item identical to `v'.
			-- (Reference or object equality,
			-- based on object_comparison.)
			-- 0 if none.
			-- (from CHAIN)
		require -- from LINEAR
			positive_occurrences: i > 0
		ensure -- from LINEAR
			non_negative_result: Result >= 0

	item: EV_MODEL
			-- Current item
			-- (from ARRAYED_LIST)
		require -- from TRAVERSABLE
			not_off: not off
		require -- from ACTIVE
			readable: readable
		require else -- from ARRAYED_LIST
			index_is_valid: valid_index (index)

	last: like first
			-- Item at last position
			-- (from ARRAYED_LIST)
		require -- from CHAIN
			not_empty: not is_empty

	frozen object_id: INTEGER_32
			-- Unique for current object in any given session
			-- (from IDENTIFIED)
		ensure -- from IDENTIFIED
			valid_id: id_object (Result) = Current

	sequential_occurrences (v: like item): INTEGER_32
			-- Number of times `v' appears.
			-- (Reference or object equality,
			-- based on object_comparison.)
			-- (from LINEAR)
		require -- from  BAG
			True
		ensure -- from BAG
			non_negative_occurrences: Result >= 0

	pebble: ANY
			-- Data to be transported by pick and drop mechanism.
			-- (from EV_MODEL)

	pebble_function: FUNCTION [ANY, TUPLE, ANY]
			-- Returns data to be transported by pick and drop mechanism.
			-- When not `Void', pebble is ignored.
			-- (from EV_MODEL)

	point: EV_COORDINATE
			-- First point of `Current'.
			-- (from EV_MODEL_SINGLE_POINTED)
		ensure -- from EV_MODEL_SINGLE_POINTED
			result_exists: Result /= Void
			result_x_equal_point_x: Result.x = point_x
			result_y_eqyal_point_y: Result.y = point_y

	point_count: INTEGER_32
			-- `Current' has one point.
			-- (from EV_MODEL_SINGLE_POINTED)
		require -- from  EV_MODEL
			True
		ensure -- from EV_MODEL
			correct: Result = point_array.count

	point_relative: EV_COORDINATE
			-- point relative to group.point.
			-- (from EV_MODEL_SINGLE_POINTED)
		ensure -- from EV_MODEL_SINGLE_POINTED
			result_exists: Result /= Void
			result_x_equal_point_x_relative: Result.x = point_x_relative
			result_y_eqyal_point_y_relative: Result.y = point_y_relative

	point_x: INTEGER_32
			-- x position of point.

	point_x_relative: INTEGER_32
			-- horizontal distance between point_x and group.point_x.
			-- (from EV_MODEL_SINGLE_POINTED)

	point_y: INTEGER_32
			-- y position of point.

	point_y_relative: INTEGER_32
			-- vertical distance between point_y and group.point_y.
			-- (from EV_MODEL_SINGLE_POINTED)

	pointer_style: EV_POINTER_STYLE
			-- Cursor displayed when pointer is over this figure.
			-- (from EV_MODEL)

	target_name: STRING_GENERAL
			-- Optional textual name describing `Current' pick and drop hole.
			-- (from EV_ABSTRACT_PICK_AND_DROPABLE)

	world: EV_MODEL_WORLD
			-- The world `Current' is part of. Void if `Current' is
			-- not part of a world
			-- (from EV_MODEL)

	x: INTEGER_32
			-- x position of the center on the screen.
			-- (from EV_MODEL)

	y: INTEGER_32
			-- y position of the center on the screen .
			-- (from EV_MODEL)

	infix "@" (i: INTEGER_32): like item assign put_i_th
			-- Item at `i'-th position
			-- Was declared in ARRAYED_LIST as synonym of i_th.
			-- (from ARRAYED_LIST)
		require -- from TABLE
			valid_key: valid_index (i)
	
feature -- Measurement

	count: INTEGER_32
			-- Number of items.
			-- (from ARRAYED_LIST)

	index_set: INTEGER_INTERVAL
			-- Range of acceptable indexes
			-- (from CHAIN)
		require -- from  INDEXABLE
			True
		ensure -- from INDEXABLE
			not_void: Result /= Void
		ensure then -- from CHAIN
			count_definition: Result.count = count

	occurrences (v: like item): INTEGER_32
			-- Number of times `v' appears.
			-- (Reference or object equality,
			-- based on object_comparison.)
			-- (from CHAIN)
		require -- from  BAG
			True
		require -- from  LINEAR
			True
		ensure -- from BAG
			non_negative_occurrences: Result >= 0
	
feature {ANY} -- Measurement

	capacity: INTEGER_32
			-- Number of available indices
			-- Was declared in ARRAY as synonym of count.
			-- (from ARRAY)
		require -- from  BOUNDED
			True
		ensure then -- from ARRAY
			consistent_with_bounds: Result = upper - lower + 1
	
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
		ensure then -- from LIST
			indices_unchanged: index = old index and other.index = old other.index
			true_implies_same_size: Result implies count = other.count

	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

	after: BOOLEAN
			-- Is there no valid cursor position to the right of cursor?
			-- (from LIST)
		require -- from  LINEAR
			True

	before: BOOLEAN
			-- Is there no valid cursor position to the left of cursor?
			-- (from LIST)
		require -- from  BILINEAR
			True

	changeable_comparison_criterion: BOOLEAN
			-- May object_comparison be changed?
			-- (Answer: yes by default.)
			-- (from CONTAINER)

	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

	exhausted: BOOLEAN
			-- Has structure been completely explored?
			-- (from LINEAR)
		ensure -- from LINEAR
			exhausted_when_off: off implies Result

	extendible: BOOLEAN is True
			-- May new items be added? (Answer: yes.)
			-- (from DYNAMIC_CHAIN)

	full: BOOLEAN
			-- Is structure filled to capacity?
			-- (from ARRAYED_LIST)
		require -- from  BOX
			True

	has (v: like item): BOOLEAN
			-- Does current include `v'?
			-- (based on v.id)
		require -- from  CONTAINER
			True
		ensure -- from CONTAINER
			not_found_in_empty: Result implies not is_empty

	has_deep (figure: EV_MODEL): BOOLEAN
			-- Does any item contains `figure'?

	invalid_rectangle: EV_RECTANGLE
			-- Rectangle that needs erasing.
			-- `Void' if no change is made.

	is_empty: BOOLEAN
			-- Is structure empty?
			-- (from FINITE)

	is_grouped: BOOLEAN
			-- Is grouped?

	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_inserted (v: EV_MODEL): BOOLEAN
			-- Has `v' been inserted at the end by the most recent put or
			-- extend?
			-- (from ARRAYED_LIST)

	is_rotatable: BOOLEAN
			-- Is this figure group rotatable?

	is_scalable: BOOLEAN
			-- Is this figure group scalable?

	is_transformable: BOOLEAN
			-- Is this figure group transformable?

	isfirst: BOOLEAN
			-- Is cursor at first position?
			-- (from CHAIN)
		ensure -- from CHAIN
			valid_position: Result implies not is_empty

	islast: BOOLEAN
			-- Is cursor at last position?
			-- (from CHAIN)
		ensure -- from CHAIN
			valid_position: Result implies not is_empty

	object_comparison: BOOLEAN
			-- Must search operations use equal rather than `='
			-- for comparing references? (Default: no, use `='.)
			-- (from CONTAINER)

	off: BOOLEAN
			-- Is there no current item?
			-- (from CHAIN)
		require -- from  TRAVERSABLE
			True

	prunable: BOOLEAN
			-- May items be removed? (Answer: yes.)
			-- (from ARRAYED_LIST)
		require -- from  COLLECTION
			True

	readable: BOOLEAN
			-- Is there a current item that may be read?
			-- (from SEQUENCE)
		require -- from  ACTIVE
			True

	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))

	update_rectangle: EV_RECTANGLE
			-- Rectangle that needs redrawing.
			-- `Void' if no change is made.

	valid_cursor (p: CURSOR): BOOLEAN
			-- Can the cursor be moved to position `p'?
			-- (from ARRAYED_LIST)

	valid_cursor_index (i: INTEGER_32): BOOLEAN
			-- Is `i' correctly bounded for cursor movement?
			-- (from CHAIN)
		ensure -- from CHAIN
			valid_cursor_index_definition: Result = ((i >= 0) and (i <= count + 1))

	valid_index (i: INTEGER_32): BOOLEAN
			-- Is `i' a valid index?
			-- (from ARRAYED_LIST)
		require -- from  TABLE
			True
		require -- from  TO_SPECIAL
			True
		ensure then -- from INDEXABLE
			only_if_in_index_set: Result implies ((i >= index_set.lower) and (i <= index_set.upper))
		ensure then -- from CHAIN
			valid_index_definition: Result = ((i >= 1) and (i <= count))

	writable: BOOLEAN
			-- Is there a current item that may be modified?
			-- (from SEQUENCE)
		require -- from  ACTIVE
			True
	
feature -- Status setting

	compare_objects
			-- Ensure that future search operations will use equal
			-- rather than `=' for comparing references.
			-- (from CONTAINER)
		require -- from CONTAINER
			changeable_comparison_criterion: changeable_comparison_criterion
		ensure -- from CONTAINER
			object_comparison

	compare_references
			-- Ensure that future search operations will use `='
			-- rather than equal for comparing references.
			-- (from CONTAINER)
		require -- from CONTAINER
			changeable_comparison_criterion: changeable_comparison_criterion
		ensure -- from CONTAINER
			reference_comparison: not object_comparison

	set_point_position_relative (ax, ay: INTEGER_32)
			-- Set position of point_relative to (`ax', `ay').
			-- (from EV_MODEL_SINGLE_POINTED)

	set_target_name (a_name: STRING_GENERAL)
			-- Assign `a_name' to target_name.
			-- (from EV_ABSTRACT_PICK_AND_DROPABLE)
		require -- from EV_ABSTRACT_PICK_AND_DROPABLE
			a_name_not_void: a_name /= Void
		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
			target_name_assigned: a_name /= target_name and a_name.is_equal (target_name)
	
feature -- Cursor movement

	back
			-- Move cursor one position backward.
			-- (from ARRAYED_LIST)
		require -- from BILINEAR
			not_before: not before

	finish
			-- Move cursor to last position if any.
			-- (from ARRAYED_LIST)
		require -- from  LINEAR
			True
		ensure then -- from CHAIN
			at_last: not is_empty implies islast
		ensure then -- from ARRAYED_LIST
			before_when_empty: is_empty implies before

	forth
			-- Move cursor one position forward.
			-- (from ARRAYED_LIST)
		require -- from LINEAR
			not_after: not after
		ensure then -- from LIST
			moved_forth: index = old index + 1

	go_i_th (i: INTEGER_32)
			-- Move cursor to `i'-th position.
			-- (from ARRAYED_LIST)
		require -- from CHAIN
			valid_cursor_index: valid_cursor_index (i)
		ensure -- from CHAIN
			position_expected: index = i

	go_to (p: CURSOR)
			-- Move cursor to position `p'.
			-- (from ARRAYED_LIST)
		require -- from CURSOR_STRUCTURE
			cursor_position_valid: valid_cursor (p)

	move (i: INTEGER_32)
			-- Move cursor `i' positions.
			-- (from ARRAYED_LIST)
		ensure -- from CHAIN
			too_far_right: (old index + i > count) implies exhausted
			too_far_left: (old index + i < 1) implies exhausted
			expected_index: (not exhausted) implies (index = old index + i)

	search (v: like item)
			-- Move to first position (at or after current
			-- position) where item and `v' are equal.
			-- If structure does not include `v' ensure that
			-- exhausted will be true.
			-- (Reference or object equality,
			-- based on object_comparison.)
			-- (from ARRAYED_LIST)
		require -- from  LINEAR
			True
		ensure -- from LINEAR
			object_found: (not exhausted and object_comparison) implies equal (v, item)
			item_found: (not exhausted and not object_comparison) implies v = item

	start
			-- Move cursor to first position if any.
			-- (from ARRAYED_LIST)
		require -- from  TRAVERSABLE
			True
		ensure then -- from CHAIN
			at_first: not is_empty implies isfirst
		ensure then -- from ARRAYED_LIST
			after_when_empty: is_empty implies after
	
feature -- Element change

	bring_forward (a_figure: EV_MODEL)
			-- Bring `a_figure' one layer forwards.
		require
			a_figure_in_figures: has (a_figure)
		ensure
			a_figure_in_group: a_figure.group = Current
			a_figure_in_current: has (a_figure)

	bring_to_front (a_figure: EV_MODEL)
			-- Bring `a_figure' to the top most layer
		require
			a_figure_in_figures: has (a_figure)
		ensure
			is_last: last = a_figure
			a_figure_in_group: a_figure.group = Current
			a_figure_in_current: has (a_figure)

	extend (v: like item)
			-- Add `v' to end.
			-- Do not move cursor.
			-- Was declared in ARRAYED_LIST as synonym of force.
			-- (from ARRAYED_LIST)
		require -- from COLLECTION
			extendible: extendible
		ensure -- from COLLECTION
			item_inserted: is_inserted (v)
		ensure then -- from BAG
			one_more_occurrence: occurrences (v) = old (occurrences (v)) + 1

	fill (other: CONTAINER [EV_MODEL])
			-- Fill with as many items of `other' as possible.
			-- The representations of `other' and current structure
			-- need not be the same.
			-- (from CHAIN)
		require -- from COLLECTION
			other_not_void: other /= Void
			extendible: extendible

	force (v: like item)
			-- Add `v' to end.
			-- Do not move cursor.
			-- Was declared in ARRAYED_LIST as synonym of extend.
			-- (from ARRAYED_LIST)
		require -- from SEQUENCE
			extendible: extendible
		ensure then -- from SEQUENCE
			new_count: count = old count + 1
			item_inserted: has (v)

	put (v: like item)
			-- Replace current item by `v'.
			-- (Synonym for replace)
			-- (from CHAIN)
		require -- from COLLECTION
			extendible: extendible
		ensure -- from COLLECTION
			item_inserted: is_inserted (v)
		ensure then -- from CHAIN
			same_count: count = old count

	put_front (v: like item)
			-- Add `v' to the beginning.
			-- Do not move cursor.
			-- (from ARRAYED_LIST)
		ensure -- from DYNAMIC_CHAIN
			new_count: count = old count + 1
			item_inserted: first = v

	put_left (v: like item)
			-- Add `v' to the left of current position.
			-- Do not move cursor.
			-- (from ARRAYED_LIST)
		require -- from DYNAMIC_CHAIN
			extendible: extendible
			not_before: not before
		ensure -- from DYNAMIC_CHAIN
			new_count: count = old count + 1
			new_index: index = old index + 1

	put_right (v: like item)
			-- Add `v' to the right of current position.
			-- Do not move cursor.
			-- (from ARRAYED_LIST)
		require -- from DYNAMIC_CHAIN
			extendible: extendible
			not_after: not after
		ensure -- from DYNAMIC_CHAIN
			new_count: count = old count + 1
			same_index: index = old index

	regroup
			-- Group the `figures' in the group.
		require
			not_is_grouped: not is_grouped
			not_is_in_group: not is_in_group
		ensure
			is_grouped: is_grouped
			all_grouped: for_all (agent {EV_MODEL}.is_in_group)
			center_is_invalid: not is_center_valid

	remove_pebble
			-- Make pebble `Void' and pebble_function `Void,
			-- Removing transport.
			-- (from EV_MODEL)
		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
			pebble_removed: pebble = Void and pebble_function = Void

	rotate (an_angle: REAL_64)
			-- Rotate around the center for `an_angle'.
		require -- from EV_MODEL
			is_rotatable: is_rotatable
		ensure -- from EV_MODEL
			center_valid: is_center_valid
		ensure then
			angle_equal_an_angle: angle = old angle + an_angle

	rotate_around (an_angle: REAL_64; ax, ay: INTEGER_32)
			-- Rotate around (`ax', `ay') for `an_angle'.
			-- (from EV_MODEL)
		require -- from EV_MODEL
			is_rotatable: is_rotatable
		ensure -- from EV_MODEL
			center_valid: is_center_valid

	scale (a_scale: REAL_64)
			-- Scale to x and y direction for `a_scale'.
			-- (from EV_MODEL)
		require -- from EV_MODEL
			is_scalable: is_scalable
			a_scale_bigger_zero: a_scale > 0.0

	scale_abs (a_scale: REAL_64)
			-- Scale to x and y direction for `a_scale'.
			-- Do not rotate around angle first.
			-- (from EV_MODEL)
		require -- from EV_MODEL
			is_scalable: is_scalable
			a_scale_bigger_zero: a_scale > 0.0

	scale_x (a_scale_x: REAL_64)
			-- Scale to x direction for `a_scale_x'.
			-- (from EV_MODEL)
		require -- from EV_MODEL
			is_scalable: is_scalable
			a_scale_x_bigger_zero: a_scale_x > 0.0

	scale_x_abs (a_scale_x: REAL_64)
			-- Scale absolute to x direction for `a_scale_x'.
			-- Do not rotate around angle first.
			-- (from EV_MODEL)
		require -- from EV_MODEL
			is_scalable: is_scalable
			a_scale_x_bigger_zero: a_scale_x > 0.0

	scale_y (a_scale_y: REAL_64)
			-- Scale to y direction for `a_scale_y'.
			-- (from EV_MODEL)
		require -- from EV_MODEL
			is_scalable: is_scalable
			a_scale_y_bigger_zero: a_scale_y > 0.0

	scale_y_abs (a_scale_y: REAL_64)
			-- Scale to y direction for `a_scale_y'.
			-- Do not rotate around angle first.
			-- (from EV_MODEL)
		require -- from EV_MODEL
			is_scalable: is_scalable
			a_scale_y_bigger_zero: a_scale_y > 0.0

	send_backward (a_figure: EV_MODEL)
			-- Send `a_figure' one layer backwards.
		require
			a_figure_in_figures: has (a_figure)
		ensure
			a_figure_in_group: a_figure.group = Current
			a_figure_in_current: has (a_figure)

	send_to_back (a_figure: EV_MODEL)
			-- Send `a_figure' to the bottom most layer.
		require
			a_figure_in_figures: has (a_figure)
		ensure
			is_at_front: first = a_figure
			a_figure_in_group: a_figure.group = Current
			a_figure_in_current: has (a_figure)

	set_accept_cursor (a_cursor: EV_POINTER_STYLE)
			-- Set `a_cursor' to be displayed when the screen pointer is over a
			-- target that accepts pebble during pick and drop.
			-- (from EV_MODEL)
		require -- from EV_ABSTRACT_PICK_AND_DROPABLE
			a_cursor_not_void: a_cursor /= Void
		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
			accept_cursor_assigned: accept_cursor.is_equal (a_cursor)

	set_deny_cursor (a_cursor: EV_POINTER_STYLE)
			-- Set `a_cursor' to be displayed when the screen pointer is not
			-- over a valid target.
			-- (from EV_MODEL)
		require -- from EV_ABSTRACT_PICK_AND_DROPABLE
			a_cursor_not_void: a_cursor /= Void
		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
			deny_cursor_assigned: deny_cursor.is_equal (a_cursor)

	set_pebble (a_pebble: like pebble)
			-- Assign `a_pebble' to pebble.
			-- (from EV_MODEL)
		require -- from EV_ABSTRACT_PICK_AND_DROPABLE
			a_pebble_not_void: a_pebble /= Void
		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
			pebble_assigned: pebble = a_pebble

	set_pebble_function (a_function: FUNCTION [ANY, TUPLE, ANY])
			-- Set `a_function' to compute pebble.
			-- (from EV_MODEL)
		require -- from EV_ABSTRACT_PICK_AND_DROPABLE
			a_function_not_void: a_function /= Void
			a_function_takes_two_integer_open_operands: a_function.valid_operands ([1, 1])
		ensure -- from EV_ABSTRACT_PICK_AND_DROPABLE
			pebble_function_assigned: pebble_function = a_function

	set_point_position (a_x, a_y: INTEGER_32)
			-- Set position of point to (`a_x', `a_y').

	set_pointer_style (a_cursor: like pointer_style)
			-- Assign `a_cursor' to pointer_style.
			-- (from EV_MODEL)
		require -- from EV_MODEL
			a_cursor_not_void: a_cursor /= Void
		ensure -- from EV_MODEL
			pointer_style_assigned: pointer_style = a_cursor

	set_x (a_x: INTEGER_32)
			-- Set x to `an_x'.
		ensure -- from EV_MODEL
			x_set: a_x = x
			center_valid: is_center_valid

	set_x_y (a_x, a_y: INTEGER_32)
			-- Set x to `an_x'.
		ensure -- from EV_MODEL
			set: a_x = x and a_y = y
			center_valid: is_center_valid

	set_y (a_y: INTEGER_32)
			-- Set y to `an_y'.
		ensure -- from EV_MODEL
			y_set: a_y = y
			center_valid: is_center_valid

	transform (a_transformation: EV_MODEL_TRANSFORMATION)
			-- Transform all points in point_array using `a_transformation'.
			-- You can do any transformation you want. You can
			-- for example rotate `Current' around an other point
			-- than the center.
			-- (from EV_MODEL)
		require -- from EV_MODEL
			a_transformation_not_void: a_transformation /= Void
			is_transformable: is_transformable

	ungroup
			-- Ungroup all `figures'.
		require
			is_grouped: is_grouped
			not_is_in_group: not is_in_group
		ensure
			is_ungrouped: not is_grouped
			none_is_in_a_group: not there_exists (agent {EV_MODEL}.is_in_group)
			center_is_invalid: not is_center_valid
	
feature -- Removal

	prune (v: like item)
			-- Remove first occurrence of `v', if any,
			-- after cursor position.
			-- Move cursor to right neighbor.
			-- (or after if no right neighbor or `v' does not occur)
			-- (from ARRAYED_LIST)
		require -- from COLLECTION
			prunable: prunable

	remove_left
			-- Remove item to the left of cursor position.
			-- Do not move cursor.
			-- (from ARRAYED_LIST)
		require -- from DYNAMIC_CHAIN
			left_exists: index > 1
		ensure -- from DYNAMIC_CHAIN
			new_count: count = old count - 1
			new_index: index = old index - 1

	remove_right
			-- Remove item to the right of cursor position
			-- Do not move cursor
			-- (from ARRAYED_LIST)
		require -- from DYNAMIC_CHAIN
			right_exists: index < count
		ensure -- from DYNAMIC_CHAIN
			new_count: count = old count - 1
			same_index: index = old index
	
feature -- Resizing

	resize (new_capacity: INTEGER_32)
			-- Resize list so that it can contain
			-- at least `n' items. Do not lose any item.
			-- (from ARRAYED_LIST)
		require -- from ARRAYED_LIST
			new_capacity_large_enough: new_capacity >= capacity
		ensure -- from ARRAYED_LIST
			capacity_set: capacity >= new_capacity
	
feature -- Conversion

	linear_representation: LINEAR [EV_MODEL]
			-- Representation as a linear structure
			-- (from LINEAR)
		require -- from  CONTAINER
			True
	
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)
		ensure then -- from ARRAY
			equal_areas: area.is_equal (other.area)

	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)

	duplicate (n: INTEGER_32): like Current
			-- Copy of sub-list beginning at current position
			-- and having min (`n', count - index + 1) items.
			-- (from ARRAYED_LIST)
		require -- from CHAIN
			not_off_unless_after: off implies after
			valid_subchain: n >= 0

	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 -- Action sequences

	conforming_pick_actions: EV_NOTIFY_ACTION_SEQUENCE
			-- Actions to be performed when a pebble that fits this hole is
			-- picked up from another source.
			-- (when drop_actions.accepts_pebble (pebble))
			-- (from EV_MODEL)

	drop_actions: EV_PND_ACTION_SEQUENCE
			-- Actions to take when pick and drop transport drops on `Current'.
			-- (from EV_MODEL)

	pick_actions: EV_PND_START_ACTION_SEQUENCE
			-- Actions to be performed when pebble is picked up.
			-- (from EV_MODEL)

	pointer_button_press_actions: EV_POINTER_BUTTON_ACTION_SEQUENCE
			-- Actions to be performed when screen pointer button is pressed.
			-- (from EV_MODEL)

	pointer_button_release_actions: EV_POINTER_BUTTON_ACTION_SEQUENCE
			-- Actions to be performed when screen pointer button is released.
			-- (from EV_MODEL)

	pointer_double_press_actions: EV_POINTER_BUTTON_ACTION_SEQUENCE
			-- Actions to be performed when screen pointer is double clicked.
			-- (from EV_MODEL)

	pointer_enter_actions: EV_NOTIFY_ACTION_SEQUENCE
			-- Actions to be performed when screen pointer enters widget.
			-- (from EV_MODEL)

	pointer_leave_actions: EV_NOTIFY_ACTION_SEQUENCE
			-- Actions to be performed when screen pointer leaves widget.
			-- (from EV_MODEL)

	pointer_motion_actions: EV_POINTER_MOTION_ACTION_SEQUENCE
			-- Actions to be performed when screen pointer moves.
			-- (from EV_MODEL)
	
feature -- Events

	bounding_box: EV_RECTANGLE
			-- Smallest orthogonal rectangular area `Current' fits in.
		ensure -- from EV_MODEL
			result_not_void: Result /= Void
			internal_is_twin: internal_bounding_box /= Result

	position_on_figure (a_x, a_y: INTEGER_32): BOOLEAN
			-- Is the point on (`a_x', `a_y') on this figure?
			-- Always returns `False', but descendants can override
			-- it to improve efficiency.
	
feature -- Iteration

	do_all (action: PROCEDURE [ANY, TUPLE [EV_MODEL]])
			-- Apply `action' to every item.
			-- Semantics not guaranteed if `action' changes the structure;
			-- in such a case, apply iterator to clone of structure instead.
			-- (from LINEAR)
		require -- from TRAVERSABLE
			action_exists: action /= Void
		require -- from ARRAY
			action_not_void: action /= Void

	do_if (action: PROCEDURE [ANY, TUPLE [EV_MODEL]]; test: FUNCTION [ANY, TUPLE [EV_MODEL], BOOLEAN])
			-- Apply `action' to every item that satisfies `test'.
			-- Semantics not guaranteed if `action' or `test' changes the structure;
			-- in such a case, apply iterator to clone of structure instead.
			-- (from LINEAR)
		require -- from TRAVERSABLE
			action_exists: action /= Void
			test_exits: test /= Void
		require -- from ARRAY
			action_not_void: action /= Void
			test_not_void: test /= Void

	for_all (test: FUNCTION [ANY, TUPLE [EV_MODEL], BOOLEAN]): BOOLEAN
			-- Is `test' true for all items?
			-- Semantics not guaranteed if `test' changes the structure;
			-- in such a case, apply iterator to clone of structure instead.
			-- (from LINEAR)
		require -- from TRAVERSABLE
			test_exits: test /= Void
		require -- from ARRAY
			test_not_void: test /= Void
		ensure then -- from LINEAR
			empty: is_empty implies Result

	there_exists (test: FUNCTION [ANY, TUPLE [EV_MODEL], BOOLEAN]): BOOLEAN
			-- Is `test' true for at least one item?
			-- Semantics not guaranteed if `test' changes the structure;
			-- in such a case, apply iterator to clone of structure instead.
			-- (from LINEAR)
		require -- from TRAVERSABLE
			test_exits: test /= Void
		require -- from ARRAY
			test_not_void: test /= Void
	
feature -- List change

	append (s: SEQUENCE [EV_MODEL])
			-- Append a copy of `s'.
		require -- from SEQUENCE
			argument_not_void: s /= Void
		ensure -- from SEQUENCE
			new_count: count >= old count

	force_i_th (fig: like item; i: INTEGER_32)
			-- Add `fig' to the group.
		require -- from  ARRAY
			True
		ensure -- from ARRAY
			inserted: i_th (i) = fig
			higher_count: count >= old count
		ensure then
			fig_in_lookup_table: fig /= Void implies lookup_table.has (fig.id)
			fig_in_group: fig /= Void implies fig.group = Current

	insert (fig: like item; i: INTEGER_32)
			-- Add `fig' to the group.
		require -- from ARRAYED_LIST
			index_small_enough: i <= count
			index_large_enough: i >= 1
		ensure -- from ARRAYED_LIST
			new_count: count = old count + 1
			index_unchanged: index = old index
			insertion_done: i_th (i) = fig
		ensure then
			fig_in_lookup_table: fig /= Void implies lookup_table.has (fig.id)
			fig_in_group: fig /= Void implies fig.group = Current

	make_from_array (a: ARRAY [EV_MODEL])
			-- Create list from array `a'.
		require -- from ARRAY
			array_exists: a /= Void
		ensure then -- from ARRAYED_LIST
			correct_position: before
			filled: count = a.count

	merge_left (other: like Current)
			-- Merge `other' into group before cursor.
			-- `other' will be empty afterwards.
		require -- from DYNAMIC_CHAIN
			extendible: extendible
			not_before: not before
			other_exists: other /= Void
			not_current: other /= Current
		ensure -- from DYNAMIC_CHAIN
			new_count: count = old count + old other.count
			new_index: index = old index + old other.count
			other_is_empty: other.is_empty

	merge_right (other: like Current)
			-- Merge `other' into group after cursor.
			-- `other' will be empty afterwards.
		require -- from DYNAMIC_CHAIN
			extendible: extendible
			not_after: not after
			other_exists: other /= Void
			not_current: other /= Current
		ensure -- from DYNAMIC_CHAIN
			new_count: count = old count + old other.count
			same_index: index = old index
			other_is_empty: other.is_empty

	prune_all (fig: like item)
			-- Remove `fig' from the group.
		require -- from COLLECTION
			prunable: prunable
		ensure -- from COLLECTION
			no_more_occurrences: not has (fig)
		ensure then -- from DYNAMIC_CHAIN
			is_exhausted: exhausted
		ensure then -- from ARRAYED_LIST
			is_after: after
		ensure then
			item_not_in_lookup_table: fig /= Void implies not lookup_table.has (fig.id)

	remove
			-- Remove item from figure.
		require -- from ACTIVE
			prunable: prunable
			writable: writable
		ensure then -- from DYNAMIC_LIST
			after_when_empty: is_empty implies after
		ensure then -- from ARRAYED_LIST
			index: index = old index
		ensure then
			item_not_in_lookup_table: not lookup_table.has (old item.id)
			item_not_in_group: not (old item).is_in_group

	replace (fig: like item)
			-- Replace current item by `fig'.
		require -- from ACTIVE
			writable: writable
		ensure -- from ACTIVE
			item_replaced: item = fig
		ensure then
			fig_in_lookup_table: fig /= Void implies lookup_table.has (fig.id)
			item_not_in_lookup_table: not lookup_table.has (old item.id)
			fig_in_group: fig /= Void implies fig.group = Current
			item_not_in_group: not (old item).is_in_group

	swap (i: INTEGER_32)
			-- Exchange item at `i'-th position with item
			-- at cursor position.
		require -- from CHAIN
			not_off: not off
			valid_index: valid_index (i)
		ensure -- from CHAIN
			swapped_to_item: item = old i_th (i)
			swapped_from_item: i_th (i) = old item
		ensure then
			item_in_lookup_table: lookup_table.has (old item.id)
			i_in_lookup_table: lookup_table.has (i_th (i).id)
			item_in_group: (old item).group = Current
			i_th_in_group: i_th (i).group = Current

	wipe_out
			-- Remove all items.
		require -- from COLLECTION
			prunable: prunable
		ensure -- from COLLECTION
			wiped_out: is_empty
		ensure then -- from DYNAMIC_LIST
			is_before: before
	
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)
	
feature -- Status Report

	accept_cursor: EV_POINTER_STYLE
			-- Accept cursor set by user.
			-- To be displayed when the screen pointer is over a target that accepts
			-- pebble during pick and drop.
			-- (from EV_MODEL)

	are_events_sended_to_group: BOOLEAN
			-- Are events for pointer_motion_actions, pointer_button_press_actions,
			-- pointer_double_press_actions,  pointer_button_release_actions
			-- pointer_enter_actions and pointer_leave_actions send to `Current's
			-- group (if any) even if `Current' catch the event. (Default True).
			-- (from EV_MODEL)

	deny_cursor: EV_POINTER_STYLE
			-- Deny cursor set by user.
			-- To be displayed when the screen pointer is not over a valid target.
			-- (from EV_MODEL)

	has_capture: BOOLEAN
			-- Are all events sent to `Current'?
			-- (from EV_MODEL)

	is_center_valid: BOOLEAN
			-- Is the position of the center valid?
			-- (from EV_MODEL)

	is_in_group: BOOLEAN
			-- Is `Current' part of a group?
			-- (from EV_MODEL)
		ensure -- from EV_MODEL
			group_defines_is_in_group: Result = (group /= Void)

	is_in_world: BOOLEAN
			-- Is `Current' part of a world?
			-- (from EV_MODEL)
		ensure -- from EV_MODEL
			world_defines_is_in_world: Result = (world /= Void)

	is_sensitive: BOOLEAN
			-- Is object sensitive to user input?
			-- (from EV_MODEL)

	is_show_requested: BOOLEAN
			-- Will `Current' be displayed when its parent is?
			-- (from EV_MODEL)
	
feature -- Status settings

	disable_capture
			-- Disable grab of all events on world.
			-- (from EV_MODEL)
		require -- from EV_MODEL
			in_world: world /= Void
			has_capture: has_capture
		ensure -- from EV_MODEL
			capture_released: not has_capture

	disable_events_sended_to_group
			-- Set are_events_sended_to_group to False.
			-- (from EV_MODEL)
		ensure -- from EV_MODEL
			events_blocked: not are_events_sended_to_group

	disable_sensitive
			-- Make object non-sensitive to user input.
			-- (from EV_MODEL)
		ensure -- from EV_MODEL
			insensitive_requested: not internal_is_sensitive

	enable_capture
			-- Grab all mouse events for world.
			-- (from EV_MODEL)
		require -- from EV_MODEL
			in_world: world /= Void
		ensure -- from EV_MODEL
			capture_set: has_capture

	enable_events_sended_to_group
			-- Set are_events_sended_to_group to True.
			-- (from EV_MODEL)
		ensure -- from EV_MODEL
			events_sended_to_group: are_events_sended_to_group

	enable_sensitive
			-- Make object sensitive to user input.
			-- (from EV_MODEL)
		ensure -- from EV_MODEL
			sensitive_requested: internal_is_sensitive

	hide
			-- Request that `Current' not be displayed even when its group is.
			-- (from EV_MODEL)
		ensure -- from EV_MODEL
			not_is_show_requested: not is_show_requested

	invalidate
			-- Some property of `Current' has changed.

	show
			-- Request that `Current' be displayed when its group is.
			-- `True' by default.
			-- (from EV_MODEL)
		ensure -- from EV_MODEL
			is_show_requested: is_show_requested

	validate
			-- Validate `Current'.
	
feature --EV_FIGURE -- Status settings

	center_invalidate
			-- The position of the center may have changed.
			-- (from EV_MODEL)
	
invariant
	is_grouped_implies_all_grouped: is_grouped implies for_all (agent {EV_MODEL}.is_in_group)
	angle_equal_current_angle: angle = current_angle
	not_is_grouped_implies_angel_equals_zero: not is_grouped implies (angle = 0)

		-- from EV_MODEL
	point_array_exists: point_array /= Void
	center_exists: center /= Void
	x_is_center_x: x = center.x
	y_is_center_y: y = center.y
	all_points_exist: all_points_exist (point_array)
	projection_matrix_not_void: projection_matrix /= Void
	is_transfomable_implies_rotatable_and_scalable: is_transformable implies (is_rotatable and is_scalable)

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

		-- from ARRAYED_LIST
	prunable: prunable
	starts_from_one: lower = 1
	empty_means_storage_empty: is_empty implies all_default

		-- from ARRAY
	area_exists: area /= Void
	consistent_size: capacity = upper - lower + 1
	non_negative_count: count >= 0
	index_set_has_same_count: valid_index_set

		-- from RESIZABLE
	increase_by_at_least_one: minimal_increase >= 1

		-- from BOUNDED
	valid_count: count <= capacity
	full_definition: full = (count = capacity)

		-- from FINITE
	empty_definition: is_empty = (count = 0)
	non_negative_count: count >= 0

		-- from INDEXABLE
	index_set_not_void: index_set /= Void

		-- from LIST
	before_definition: before = (index = 0)
	after_definition: after = (index = count + 1)

		-- from CHAIN
	non_negative_index: index >= 0
	index_small_enough: index <= count + 1
	off_definition: off = ((index = 0) or (index = count + 1))
	isfirst_definition: isfirst = ((not is_empty) and (index = 1))
	islast_definition: islast = ((not is_empty) and (index = count))
	item_corresponds_to_index: (not off) implies (item = i_th (index))
	index_set_has_same_count: index_set.count = count

		-- from ACTIVE
	writable_constraint: writable implies readable
	empty_constraint: is_empty implies (not readable) and (not writable)

		-- from BILINEAR
	not_both: not (after and before)
	before_constraint: before implies off

		-- from LINEAR
	after_constraint: after implies off

		-- from TRAVERSABLE
	empty_constraint: is_empty implies off

		-- from DYNAMIC_CHAIN
	extendible: extendible

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_MODEL_GROUP