#lang racket (require 2htdp/universe) (require 2htdp/image) (define (draw-number n) (place-image (text (number->string n) 44 'red) 50 50 (empty-scene 100 100))) ;; Nat Nat String -> Nat ;; make the clock tick n times, expected expected-n files in dir (define (create-n-images n expected-n dir) (unless (directory-exists? dir) (make-directory dir)) (parameterize ([current-directory dir]) (for-each delete-file (directory-list))) (with-output-to-file (format "./~a/index.html" dir) (lambda () (displayln "

")) #:exists 'replace) (define final-world (big-bang 0 (on-tick add1) (stop-when (curry = n)) (on-draw draw-number) (record? dir))) (sleep 1) (define number-of-png (parameterize ([current-directory dir]) (define dlst (directory-list)) ; (displayln dlst) (length (filter (lambda (f) (regexp-match "\\.png" (path->string f))) dlst)))) (unless (= expected-n number-of-png) (error 'record? "(~s, ~s) didn't record proper number of images: ~s" n dir number-of-png))) (create-n-images 3 3 "images3/") (create-n-images 0 0 "images0/")