Grafik i Racket
Grafik i Racket
Grafik i Racket
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<strong>Grafik</strong>motorer IV<br />
Det händer inte så mycket... Vi provar en<br />
intressantare renderingsfunktion:<br />
(define *angle* 0.0)<br />
(define (render-fn canvas dc)<br />
(send dc translate 50 50)<br />
(send dc rotate *angle*)<br />
(send dc draw-rectangle -25 -25 50 50)<br />
(send dc rotate (- *angle*))<br />
(send dc translate (- 50) (- 50)))<br />
(tick!) blir nu:<br />
(define (tick!)<br />
(set! *angle* (+ *angle* (/ 1 6.28))))<br />
(send *my-canvas* refresh))