turntogrey.clj

(ns imaging.core)

(import 'java.awt.image.BufferedImage)
(use 'clojure.java.io)
(import '[javax.swing JFrame JLabel ImageIcon])

(defn setpxl [^BufferedImage image data]
  (let [h (.getHeight image)
    w (.getWidth image)]
  (.setRGB image 0 0 w h ^ints data 0 w)
) )

(defn getrgb [rgb]
 (let [r  (bit-shift-right (bit-and rgb (int 0x00FF0000)) 16)
    g  (bit-shift-right (bit-and rgb (int 0x0000FF00)) 8)
    b  (bit-and rgb (int 0x000000FF))]
[r g b])
)

(defn getpxl [^BufferedImage img]
  (.getRGB img 0 0  (.getWidth img) (.getHeight img) nil 0 (.getWidth img) )
	)

(defn graycalc [[r g b]]
  (let [gray (int (/ (+ r g b) 3))
    r  (bit-shift-left gray 16)
    g  (bit-shift-left gray 8)
    b  gray
    a  (bit-shift-left 0x00 24)
    ]
  (int (bit-or a r g b))))

(defn testrgb []
  (let [img (time (javax.imageio.ImageIO/read (as-file "resources/cat.jpg")))
    h (.getHeight img)
    w (.getWidth img)
    arr (time (int-array (getpxl img)))
    gray (time
          ;;why is amap so slow?

          ;;400ms
          ; (int-array (map #(graycalc (getrgb %1)) arr))

          ;;8000ms
          (amap ^ints arr idx ret ^int (graycalc (getrgb (aget ^ints arr idx))))
          )

    frame (JFrame. "grayscale image")
    label (JLabel. (ImageIcon. img))
    panel (.getContentPane frame)]

(-> panel 
	(.add label))
    (.setSize frame w h)
    (.setVisible frame true)

(time (setpxl img gray))
(.repaint panel)
))