File examples/canvas-sample.scm from the latest check-in

(use iup canvas-draw)
(import canvas-draw-iup)

 (define dlg
   (dialog #:title "Test" #:minsize "320x240"
     (canvas #:action (make-canvas-action
       (lambda (cnv x y)
         (canvas-clear! cnv)
         (canvas-text! cnv 40 40 "Hello world!"))))))

 (show dlg)
 (main-loop)