    indexing
    	description: "Projectors that make representations of world on%NEV_DRAWING_AREA."
    	legal: "See notice at end of class."
    	status: "See notice at end of class."
    	keywords: "figures, project, pointer, drawing, points"
    	date: "$Date: 2006-01-22 18:25:44 -0800 (Sun, 22 Jan 2006) $"
    	revision: "$Revision: 56675 $"

    class interface
    	EV_DRAWING_AREA_PROJECTOR

    create
    	make (a_world: EV_FIGURE_WORLD; a_drawing_area: EV_DRAWING_AREA)
    			-- Create with `a_world' and `a_drawing_area'.
    		require
    			a_world_not_void: a_world /= Void
    			a_drawing_area_not_void: a_drawing_area /= Void

    	make_with_buffer (a_world: EV_FIGURE_WORLD; a_buffer: EV_PIXMAP; a_drawing_area: EV_DRAWING_AREA)
    			-- Create with `a_world', `a_drawing_area' and `a_buffer'.
    		require
    			a_world_not_void: a_world /= Void
    			a_drawing_area_not_void: a_drawing_area /= Void
    			a_buffer_not_void: a_buffer /= Void

    feature -- Access

    	area: EV_DRAWABLE
    			-- Area associated with widget.
    			-- `Void' if no buffer is used.
    			-- (from EV_WIDGET_PROJECTOR)

    	area_x: INTEGER_32
    			-- Coordinates of top-left corner of displayed part of drawable.
    			-- (0, 0) when no buffer is used.
    			-- (from EV_WIDGET_PROJECTOR)

    	area_y: INTEGER_32
    			-- Coordinates of top-left corner of displayed part of drawable.
    			-- (0, 0) when no buffer is used.
    			-- (from EV_WIDGET_PROJECTOR)

    	drawable: EV_DRAWABLE
    			-- Drawable surface (screen, drawing area or pixmap).
    			-- (from EV_FIGURE_DRAWER)

    	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)

    	widget: EV_WIDGET
    			-- `device' if conforms to EV_WIDGET.
    			-- `Void' otherwise.
    			-- (from EV_WIDGET_PROJECTOR)

    	world: EV_FIGURE_WORLD
    			-- Figure-world that will be projected.
    			-- (from EV_PROJECTOR)

    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

    	buffer_used: BOOLEAN
    			-- Is drawable only a buffer area for area?
    			-- (from EV_WIDGET_PROJECTOR)

    	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

    	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

    	set_world (a_world: EV_FIGURE_WORLD)
    			-- Set world to `a_world'.
    			-- (from EV_PROJECTOR)
    		require -- from EV_PROJECTOR
    			a_world_exists: a_world /= Void
    		ensure -- from EV_PROJECTOR
    			world_assigned: world = a_world

    feature -- Element change

    	change_area_position (a_x, a_y: INTEGER_32)
    			-- area has moved to (`a_x', `a_y') of drawable.
    			-- (from EV_WIDGET_PROJECTOR)
    		require -- from EV_WIDGET_PROJECTOR
    			valid_position: a_x >= 0 and a_y >= 0

    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

    	clear_device
    			-- Erase entire canvas.
    			-- (from EV_WIDGET_PROJECTOR)

    	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)

    	full_project
    			-- Project entire area.
    			-- (from EV_WIDGET_PROJECTOR)

    	is_projecting: BOOLEAN
    			-- Is a project currently being performed?
    			-- Then, do not start a new one.
    			-- (from EV_PROJECTION_ROUTINES)

    	project
    			-- Make a standard projection of world on device.
    			-- (from EV_WIDGET_PROJECTOR)

    	project_rectangle (u: EV_RECTANGLE)
    			-- Project area under `u'.
    			-- (from EV_WIDGET_PROJECTOR)

    	register_figure (a_figure: EV_FIGURE; a_routine: PROCEDURE [ANY, TUPLE [EV_FIGURE]])
    			-- Assign `a_routine' for drawing of `a_figure'.
    			-- (from EV_PROJECTION_ROUTINES)

    	update_rectangle (u: EV_RECTANGLE; a_x, a_y: INTEGER_32)
    			-- Flush `u' on area at (`a_x', `a_y').
    			-- (from EV_WIDGET_PROJECTOR)
    		require -- from EV_WIDGET_PROJECTOR
    			buffer_used: buffer_used

    feature -- Implementation

    	default_colors: EV_STOCK_COLORS
    			-- Once access to `EV_STOCK_COLORS'.
    			-- (from EV_PROJECTION_ROUTINES)
    		require -- from  EV_FIGURE_DRAWER
    			True

    feature -- Basic Operations

    	draw_grid
    			-- Draw grid on canvas.
    			-- `world.point' is the origin of the grid.
    			-- (from EV_FIGURE_DRAWER)

    feature -- Element Change

    	set_drawable (a_drawable: EV_DRAWABLE)
    			-- Set drawable to `a_drawable'.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWER
    			a_drawable_not_void: a_drawable /= Void
    		ensure -- from EV_FIGURE_DRAWER
    			assigned: drawable = a_drawable

    feature -- Figure drawing

    	draw_figure_arc (arc: EV_FIGURE_ARC)
    			-- Draw standard representation of `arc' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			arc_not_void: arc /= Void

    	draw_figure_dot (dot: EV_FIGURE_DOT)
    			-- Draw standard representation of `dot' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			dot_not_void: dot /= Void

    	draw_figure_ellipse (ellipse: EV_FIGURE_ELLIPSE)
    			-- Draw standard representation of `ellipse' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			ellipse_not_void: ellipse /= Void

    	draw_figure_equilateral (eql: EV_FIGURE_EQUILATERAL)
    			-- Draw standard representation of `eql' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			eql_not_void: eql /= Void

    	draw_figure_line (line: EV_FIGURE_LINE)
    			-- Draw standard representation of `line' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			line_not_void: line /= Void

    	draw_figure_picture (picture: EV_FIGURE_PICTURE)
    			-- Draw standard representation of `picture' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			picture_not_void: picture /= Void

    	draw_figure_pie_slice (slice: EV_FIGURE_PIE_SLICE)
    			-- Draw standard representation of `slice' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			slice_not_void: slice /= Void

    	draw_figure_polygon (polygon: EV_FIGURE_POLYGON)
    			-- Draw standard representation of `polygon' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			polygon_not_void: polygon /= Void

    	draw_figure_polyline (line: EV_FIGURE_POLYLINE)
    			-- Draw standard representation of `polyline' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			line_not_void: line /= Void

    	draw_figure_rectangle (rectangle: EV_FIGURE_RECTANGLE)
    			-- Draw standard representation of `rectangle' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			rectangle_not_void: rectangle /= Void

    	draw_figure_rounded_rectangle (f: EV_FIGURE_ROUNDED_RECTANGLE)
    			-- Draw standard representation of `f' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			f_not_void: f /= Void

    	draw_figure_star (star: EV_FIGURE_STAR)
    			-- Draw standard representation of `star' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			star_not_void: star /= Void

    	draw_figure_text (text_figure: EV_FIGURE_TEXT)
    			-- Draw standard representation of `text_figure' to canvas.
    			-- (from EV_FIGURE_DRAWER)
    		require -- from EV_FIGURE_DRAWING_ROUTINES
    			text_figure_not_void: text_figure /= 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
    		-- from EV_PROJECTOR
    	world_exists: world /= Void

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

    		-- from EV_FIGURE_DRAWER
    	drawable_not_void: drawable /= Void

    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_DRAWING_AREA_PROJECTOR