mandelbrot set

sample/mandelbrot.rb

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+# awesome (but insanely slow) Mandelbrot set drawing
+# feel free to mess around with various variables to
+# find a better / faster solution
+
+require 'rbdraw'
+include Draw
+
+# higher resolutions are *much* nicer, but 400, 300
+# should complete in ~30 seconds
+$w = 400
+$h = 300
+
+w = Window.new
+
+w.height = $h
+w.width = $w
+
+w.show
+
+g = w.graphics
+
+MAX_ITER = 255
+
+g.sync_on_draw false
+
+# this strategy was shamelessly stolen from RosettaCode
+# http://rosettacode.org/wiki/Mandelbrot_set#haXe
+
+sx = 3.0 / ($w - 1)
+sy = 2.0 / ($h - 1)
+
+(0...$h).each {|y|
+  ci = y * sy - 1.0
+  (0...$w).each {|x|
+    k = 0
+    zr = 0
+    zi = 0
+    cr = x * sx - 2.0
+
+    while k <= MAX_ITER and zr * zr + zi * zi <= 4
+      temp = zr * zr - zi *zi + cr
+      zi = 2 * zr * zi + ci
+      zr = temp
+      k += 1
+    end
+
+    g.color k > MAX_ITER ? 0 : k * 0x010
+    g.point(x, y)
+
+  }
+  # Sync after every line, makes drawing less choppy
+  g.sync
+}
+g.sync
+
+gets
+