Eiffel Media API
Overview Cluster Class Classes Index      Previous Next      Top Features

em.video.figure

Class EM_FIGURE


Direct ancestors

EM_DRAWABLE

Known direct descendants

EM_MULTI_POINTED_FIGURE, EM_CLOSED_FIGURE

Features

Invariants

indexing

description

Abstraction for drawable figures. Drawable figures have a line_width and a line_color in which they will be drawed.

A figure basicaly is defined through points (points) so is its position and size (x, y, width, height).
When the points are changed the position and size needs updating (update_bounding_box).
When the position of a figure is changed (set_x_y) all its points have to be moved accordingly.

To ensure updating of the bounding box, descendants have to call update_bounding_box whenever
something changes that influences the 'bounding_box' of the figure.

date

$Date: 2005/10/23 10:57:04 $

revision

$Revision: 1.4 $

deferred class

EM_FIGURE

inherit

EM_DRAWABLE

feature -- Status report

is_size_fixed: BOOLEAN

-- Should Current not scale when drawed?
-- True means that the object will be drawed unscaled
-- but its position (reference_point) will still be transformed correctly
-- if drawed on a transformed scaled coordinate system
-- (This is handled accordingly by draw_object of EM_SURFACE)

-- (From EM_DRAWABLE)

line_color: EM_COLOR

-- Line color used to draw Current

line_width: DOUBLE

-- Line width used to draw Current

x: INTEGER

-- Horizontal position, distance in pixels from left

-- (From EM_DRAWABLE)

y: INTEGER

-- Vertical position, distance in pixels from top

-- (From EM_DRAWABLE)

feature -- Status setting

set_line_color (a_color: EM_COLOR)

-- Set line_color to a_color.

require
a_color_not_void: a_color /= Void
ensure
line_color_assigned: line_color = a_color
set_line_width (a_width: DOUBLE)

-- Set line_width to a_width.

require
a_width_not_negative: a_width >= 0
ensure
line_width_set: line_width = a_width
set_size_fixed (a_boolean: BOOLEAN)

-- Set is_size_fixed to a_boolean.

-- (From EM_DRAWABLE)

ensure
size_fixed_set: is_size_fixed = a_boolean
set_x (x_position: INTEGER)

-- Set x to x_position.

-- (From EM_DRAWABLE)

ensure
x_set: x = x_position
set_x_y (x_position: INTEGER; y_position: INTEGER)

-- Set x and y to x_position and y_position.
-- Moves all contained points accordingly.

-- (From EM_DRAWABLE)

ensure
x_set: x = an_x
y_set: y = a_y
set_y (y_position: INTEGER)

-- Set y to y_position.

-- (From EM_DRAWABLE)

ensure
y_set: y = y_position
update_bounding_box

-- Recalculate bounding_box (x, y, width, height)
-- to surround all points.

feature -- Drawing

draw (a_surface: EM_SURFACE)

-- Draw Current onto a_surface.

-- (From EM_DRAWABLE)

require
a_surface_not_void: a_surface /= Void
draw_part (a_rect: EM_RECT; a_surface: EM_SURFACE)

-- Draw rectangular part of Current defined by a_rect to a_surface.
-- (Subclasses could redefine this feature for providing an implementation
-- with better performance, otherwise its just done per default by
-- transforming and clipping coordinates on a_surface before calling draw).

-- (From EM_DRAWABLE)

require
a_surface_not_void: a_surface /= Void
a_rect_not_void: a_rect /= Void

feature -- Mouse events

events_initialized: BOOLEAN

-- Have events been initialized?

-- (From EM_DRAWABLE)

initialize_events

-- Event initialization.
-- Needs to be called before subscribing for events.

-- (From EM_DRAWABLE)

require
not_yet_initialized: not events_initialized
ensure
events_initialized: events_initialized
mouse_button_down_event_initialized: mouse_button_down_event /= Void
mouse_button_up_event_initialized: mouse_button_up_event /= Void
mouse_motion_event_initialized: mouse_motion_event /= Void
mouse_button_down_event: EM_EVENT_TYPE [TUPLE [EM_MOUSE_EVENT]]

-- Mouse button down event,
-- gets published when the mouse button is pressed over Current,
-- an EM_MOUSEBUTTON_EVENT is passed as argument

-- (From EM_DRAWABLE)

mouse_button_up_event: EM_EVENT_TYPE [TUPLE [EM_MOUSE_EVENT]]

-- Mouse button up event,
-- gets published when the mouse button is released over Current,
-- an EM_MOUSEBUTTON_EVENT is passed as argument

-- (From EM_DRAWABLE)

mouse_motion_event: EM_EVENT_TYPE [TUPLE [EM_MOUSE_EVENT]]

-- Mouse button up event,
-- gets published when the mouse button is released over Current,
-- an EM_MOUSEMOTION_EVENT is passed as argument

-- (From EM_DRAWABLE)

publish_mouse_event (a_mouse_event: EM_MOUSE_EVENT)

-- Publish mouse event when a_mouse_event occured on Current.
-- Descendants should redefine this feature
-- for only catching and publishing their mouse events when mouse pointer
-- is realy inside object or for
-- distributing mouse events to child objects.

-- (From EM_DRAWABLE)

require
a_mouse_event_not_void: a_mouse_event /= Void

feature -- Queries

bounding_box: EM_ORTHOGONAL_RECTANGLE

-- Orthogonal rectangle surrounding Current; (i.e. usefull
-- for visibility testing if it intersects with
-- coordinate_area of EM_SURFACE) TODO: We create a new
-- one on each call. Maybe there is a more efficient way to
-- do that?

-- (From EM_DRAWABLE)

ensure
result_not_void: Result /= Void
height: INTEGER

-- Height of Current defining its bounding_box (x, y, width, height).

-- (From EM_DRAWABLE)

ensure
result_not_negative: Result >= 0
reference_point: EM_VECTOR_2D

-- Reference point of Current relative to which it should be positioned.
-- (i.e. important when drawn on a scaled coordinate system and is_size_fixed is True)

-- (From EM_DRAWABLE)

ensure
result_not_void: Result /= Void
width: INTEGER

-- Width of Current defining its bounding_box (x, y, width, height).

-- (From EM_DRAWABLE)

ensure
result_not_negative: Result >= 0

invariant

line_color_not_void: line_color /= Void
line_width_not_negative: line_width >= 0.0
points_not_void: points /= Void

-- From EM_DRAWABLE
mouse_button_down_event_initialized: events_initialized implies mouse_button_down_event /= Void
mouse_button_up_event_initialized: events_initialized implies mouse_button_up_event /= Void
mouse_motion_event_initialized: events_initialized implies mouse_motion_event /= Void

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

end