Leif in Clojure

gistfile1.clj

(import (javax.swing JFrame JPanel)
        (java.awt Color Dimension Graphics)
        (java.awt.image BufferedImage WritableRaster))

(defn construct-frame [width height panel]
  "Creates and displays a JFrame of the given dimensions with
  the panel added to it"
  (let [frame (JFrame.)]
      (.setPreferredSize panel (Dimension. width height))
      (doto frame
        (.add panel)
        .pack
        (.setLocationRelativeTo nil)
        (.setDefaultCloseOperation JFrame/EXIT_ON_CLOSE)
         .show)))

(defn get-pixel [x y #^WritableRaster wr]
  (let [pix (int-array [0,0,0])]
            (.getPixel wr (int x) (int y) pix)
        (int-array pix)))

(defn set-pixel [x y pixel #^WritableRaster wr]
  (.setPixel wr (int x) (int y) (int-array pixel)))

(defn random-red-green-blue []
  ([[255,0,0] [0,255,0] [0,0,255]] (rand-int 3)))

(defn randomize-canvas [width height #^WritableRaster wr]
  (doseq [pixel (for [y (range height) x (range width)] [x y])]
    (let [[x y] pixel]
      (set-pixel x y (random-red-green-blue) wr))))

(defn render-pixels [width height #^WritableRaster wr]
  (let [x (inc (rand-int (- width 2)))
        y (inc (rand-int (- height 2)))
        pixel (get-pixel x y wr)]
    (set-pixel x (dec y) pixel wr)
    (set-pixel x (inc y) pixel wr)
    (set-pixel (inc x) y pixel wr)
    (set-pixel (dec x) y pixel wr)))

(defn leif [width height iters-per-frame]
  (let [img (BufferedImage. width height (BufferedImage/TYPE_INT_RGB))
        panel (proxy [JPanel] [] (paint [g] (.drawImage g img 0 0 (Color/white) nil)))
        writeable-raster (.getRaster img)]
    (construct-frame width height panel)
    (randomize-canvas width height writeable-raster)
    (while true 
      (dotimes [n iters-per-frame]
        (render-pixels width height writeable-raster))
        (Thread/sleep 15)
        (.repaint panel))))
    
(leif 640 400 4711)