PaulSandoz

/*
 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *

PaulSandoz

(defn render-image [image]
  (let [out (ByteArrayOutputStream.)]
    (do (ImageIO/write image "png" out) (ByteArrayInputStream. (.toByteArray out)))))

; ":use" needed  for compojure.response
(extend-protocol Renderable
  BufferedImage
  (render [image _]
    (-> (ring.util.response/response (render-image image))
        (ring.util.response/content-type "image/png"))))

PaulSandoz

(defn- image-mandel-doseq
  ([[dx dy w h m] limit]
    (let [image (BufferedImage. w h BufferedImage/TYPE_INT_RGB)]
      (image-mandel-doseq dx dy m image limit)))
  ([dx dy m ^BufferedImage image limit]
    (let [raster (.getRaster image)]
      (doseq [[x y rate] m]
        (.setPixel raster (int (- x dx)) (int (- y dy)) (ints (rgb (angle rate limit)))))
      [dx dy image])))

PaulSandoz

(defn image-mandel
  ([size a b limit]
    (let [[_ _ ms] (mandelbrot-seqs 1 size a b limit)
          [_ _ image] (image-mandel-doseq (first ms) limit)]
        image))
  ([n size a b limit]
    (let [[w h ms] (mandelbrot-seqs n size a b limit)
          image (BufferedImage. w h BufferedImage/TYPE_INT_RGB)
          raster (.getRaster image)]
      (dorun

PaulSandoz

(defn text-mandel [size a b limit]
  (let [[w _ ms] (mandelbrot-seqs 1 size a b limit)
        [_ _ _ _ m] (first ms)
         s (map (fn [[_ _ i]]
                         (if (zero? i) " " (str (int (* 9 (/ i limit)))))) m)]
    (println
      (interpose \newline
        (map #(apply str %)
          (partition w s))))))

PaulSandoz

(defn- ranges [l s]
  (partition 2 1 [l] (range 0 l s)))

PaulSandoz

(defn- mandelbrot-seqs [n size a b limit]
  (let [[lower upper] (normalize a b)
        d (delta size lower upper)
        [w h] (dimensions size lower upper)]
    [w h
     (for [[ly uy] (ranges h (int (/ h (min n h))))]
       [ 0 ly w (- uy ly) (mandelbrot-seq (range 0 w) (range ly uy) lower d limit) ]
       )]))

PaulSandoz

(defn- mandelbrot-seq [x-range y-range [lr li] d limit]
  (for [y y-range :let [i (+ li (* y d))]
        x x-range :let [r (+ lr (* x d))]]
    [x y (mandelbrot r i limit)]))

PaulSandoz

(defn mandelbrot [c ^long limit]
    (loop [rate limit
           s (iterate #(+ (* % %) c) 0.0)]
        (if (and (> rate 0) (< (abs (first s)) 2.0))
          (recur (dec rate) (rest s))
          rate)))

PaulSandoz

(defn mandelbrot [^double cr ^double ci ^long limit]
  (loop [rate limit
         zr 0.0
         zi 0.0]
    (let [zr2 (* zr zr)
          zi2 (* zi zi)]
    (if (and (> rate 0) (< (+ zr2 zi2) 4.0))
      (recur (dec rate) (+ cr (- zr2 zi2)) (+ ci (* 2.0 (* zr zi))) )
      rate))))