image.clj

(defn duotone-filter [^java.awt.image.Raster raster]
  (let [dest (.createCompatibleWritableRaster raster)
        bands (.getNumBands dest)
        dest-pixel (int-array bands)
        w (.getWidth raster)
        h (.getHeight raster)
        ]
    (loop [y 0]
      (when (< y h)
        (loop [x 0
               ^ints pixel nil]
          (when (< x w)
            (let [pixel (.getPixel raster (int x) (int y) pixel)]
              (aset dest-pixel 0 (int (aget pixel 2)))
              (aset dest-pixel 1 (int (aget pixel 1)))
              (aset dest-pixel 2 (int (aget pixel 0)))
              (.setPixel dest x y dest-pixel)
              (recur (inc x) pixel))))
        (recur (inc y))))
    dest))