indexing

	description: "[

		Any font class should implement EM_FONT. EM_FONT gives the possibility
		to draw a CHARACTER to an EM_SURFACE.

	]"
	date: "$Date$"
	revision: "$Revision$"

deferred class EM_FONT

feature -- Measurement

	width (a_character: CHARACTER): INTEGER is
			-- Width of `a_character'
		deferred
		end

	height (a_character: CHARACTER): INTEGER is
			-- Height of `a_character'
		deferred
		end

	string_width (a_string: STRING): INTEGER is
			-- Width of `a_string'
		deferred
		end

	string_height (a_string: STRING): INTEGER is
			-- Height of `a_string'
		deferred
		end

feature -- Drawing

	draw ( a_character: CHARACTER; a_surface: EM_SURFACE; x: INTEGER; y:INTEGER) is
			-- Draws `a_character' on `a_surface' to position `x' `y'.
		require
			a_surface /= void
		deferred
		end

	draw_part ( rect: EM_BLITTING_RECTANGLE; a_character: CHARACTER; a_surface: EM_SURFACE; x: INTEGER; y: INTEGER) is
			-- Draws `rect' part of `a_character' on `a_surface' to position `x' `y'.
		require
			a_surface /= void
			rect /= void
		deferred
		end

	draw_string (a_string: STRING; a_surface: EM_SURFACE; x: INTEGER; y: INTEGER) is
			-- Draws `a_string' on `a_surface' to position `x' `y'.
		require
			a_string_not_void: a_string /= void and then a_string.count > 0
			a_surface_not_void: a_surface /= void
		deferred
		end

end