indexing
	description: "[
	
		Objects that have a color and need to be updated when it changes
		
	]"
	author: ""
	date: "$Date$"
	revision: "$Revision$"

deferred class
	EM_VIZ_COLORED

inherit
	EM_VIZ_UPDATEABLE

feature -- Initialization

	make_colored (a_color: like color) is
			-- Initialize
		require
			color_exists: a_color /= Void
		do
			set_color (a_color)
		ensure
			set: color = a_color
		end

feature -- Access

	color: EM_COLOR
			-- Color of object

feature -- Element change

	set_color (a_color: like color) is
			-- Set color to `a_color' and notify
		require
			color_exists: a_color /= Void
		do
			color := a_color
			expire
		ensure
			set: color = a_color
			expired: needs_update
		end

invariant

	color_exists: color /= Void

end