; This file contains all the code needed to draw lines except for
; the procedures make-vect, xcor-vect and ycor-vect, which implement
; vectors.

; Do not submit the following eight expressions

(require (lib "graphics.ss" "graphics"))

(open-graphics)

(define size 400)

(define w (open-viewport "demo" size size))

(define line-drawer (draw-line w))

(define (clear) ((clear-viewport w)))

(define (drawline p-start p-end)
  (line-drawer (make-posn (xcor-vect p-start)
                          (- size 1 (ycor-vect p-start)))
               (make-posn (xcor-vect p-end)
                          (- size 1 (ycor-vect p-end)))))

(define 2pi (* 2 3.141592653589793))

; Enter all your code after this point and paste only the code
; you added to the automated tester.

; you must define make-vect, xcor-vect, ycor-vect, polygon