#cs(module draw-sig mzscheme
  (provide core-draw^ draw^)
  (require (lib "unitsig.ss"))
  
;; xxx-solid-rect cannot be called xxx-solid-rectangle because that
;; interferes with the existing xxx-solid-rectangle name in our unit
;; calculus -- mf 

  (define-signature core-draw^
       (start 
        start/cartesian-plane
        stop 
        draw-circle draw-solid-disk draw-solid-rect draw-solid-line
	draw-solid-string
        clear-circle clear-solid-disk clear-solid-rect clear-solid-line
	clear-solid-string
        clear-all
        sleep-for-a-while
        wait-for-mouse-click ; -> posn
        get-key-event   ; -> (union #f char symbol)
	get-mouse-event ; -> (union #f posn)
        get-@VP        
        big-bang        ; World -> true
        on-key-event    ; (union char symbol) World -> World 
        on-tick-event   ; World -> World 
        end-of-time     ; -> World
        ))
  
  (define-signature draw^ core-draw^))