gistfile1.clj

(defmacro my-amap
  "Maps an expression across an array a, using an index named idx, and
  return value named ret, initialized to a clone of a, then setting 
  each element of ret to the evaluation of expr, returning the new 
  array ret."
  {:added "1.0"}
  [a idx ret expr]
  `(let [a# ~a
         ~ret (aclone a#)]
     (loop  [~idx (int 0)]
       (if (< ~idx  (alength a#))
         (do
           (aset ~ret ~idx (~expr (aget a# ~idx)))
           (recur (unchecked-inc ~idx)))
         ~ret))))


(defn get-raster [^java.awt.image.BufferedImage img]
  (.getRaster img))

(defn get-samples [^java.awt.image.WritableRaster raster x y w h b ^ints a]
  (.getSamples raster x y w h b a))

(defn set-samples [^java.awt.image.WritableRaster raster x y w h b ^ints a]
  (.setSamples raster x y w h b a))

(set-samples (get-raster *luma*) 0 0 555 149 0 
  (my-amap ^ints (get-samples (get-raster *luma*) 0 0 555 149 0 (int-array (* 555 149)))
    idx
    ^ints ret (fn [x] (if (< 49 x) 255 x))))