Data commit

Task/Mandelbrot-set/Racket/mandelbrot-set.rkt

@@ -0,0 +1,26 @@
+#lang racket
+
+(require racket/draw)
+
+(define (iterations a z i)
+  (define z′ (+ (* z z) a))
+  (if (or (= i 255) (> (magnitude z′) 2))
+      i
+      (iterations a z′ (add1 i))))
+
+(define (iter->color i)
+  (if (= i 255)
+      (make-object color% "black")
+      (make-object color% (* 5 (modulo i 15)) (* 32 (modulo i 7)) (* 8 (modulo i 31)))))
+
+(define (mandelbrot width height)
+  (define target (make-bitmap width height))
+  (define dc (new bitmap-dc% [bitmap target]))
+  (for* ([x width] [y height])
+    (define real-x (- (* 3.0 (/ x width)) 2.25))
+    (define real-y (- (* 2.5 (/ y height)) 1.25))
+    (send dc set-pen (iter->color (iterations (make-rectangular real-x real-y) 0 0)) 1 'solid)
+    (send dc draw-point x y))
+  (send target save-file "mandelbrot.png" 'png))
+
+(mandelbrot 300 200)