Metronome: Difference between revisions

</lang>

=={{header|Racket}}==

<lang Racket>

#lang racket

(require racket/gui)

(define msec 500)

(define sounds '("c:/home/stuff/sounds/Clicked.wav"

"c:/home/stuff/sounds/Bink.wav"))

(define colors '("red" "green"))

(define f

(new frame% [label "Metronome"] [width 200] [height 200]))

(define c

(new (class canvas%

(define brushes

(map (λ(c) (new brush% [color c] [style 'solid])) colors))

(define cur 0)

(define/override (on-paint)

(send* (send this get-dc)

(clear)

(set-brush (list-ref brushes cur))

(draw-rectangle 0 0 200 200)))

(define/public (flip!)

(set! cur (modulo (add1 cur) (length sounds)))

(play-sound (list-ref sounds cur) #f)

(on-paint))

(super-new))

[parent f]))

(define (flip)

(define init (current-inexact-milliseconds))

(define next (+ msec init))

(define ticks 1)

(let loop ()

(when (> (current-inexact-milliseconds) next)

(set! ticks (add1 ticks))

(set! next (+ init (* msec ticks)))

(queue-callback (λ() (send c flip!))))

(sleep 0.01)

(loop)))

(send* f (center) (show #t))

(void (thread flip))