canvas.rkt

#lang racket/gui

(define frame (new frame%
                   [label "Example"]
                   [width 300]
                   [height 300]))

(define black (make-color 0 0 0))

(new canvas% [parent frame]
     [paint-callback
      (lambda (canvas dc)
             (send dc set-scale 3 3)
             (send dc set-text-foreground "blue")
             (send canvas set-canvas-background black)
             (send dc draw-text "Don't Panic!" 0 0))])

(send frame show #t)