nonograms-dojo.clj

(ns nono.core
  (:import [javax.imageio ImageIO]
           [java.io File]))

(def test-path "/Users/not-going-to-show-my-user/Downloads/sample.bmp")

(defn extract-rgb [pixel]
  (let [r (bit-and 0x000000FF (bit-shift-right pixel 16))
        g (bit-and 0x000000FF (bit-shift-right pixel 8))
        b (bit-and 0x000000FF pixel)]
  (/ (+ r g b) 3)))

(defn read-image [path]
  (let [file (File. path)
        img (ImageIO/read file)
        h (.getHeight img)
        w (.getWidth img)]
    (mapv (fn [row-idx]
           (mapv (fn [col-idx]
                   (-> img
                       (.getRGB col-idx row-idx)
                       extract-rgb))
                 (range 1 w)))
          (range 1 h))))

(defn pixelate [pixels size]
  (let [cols (quot (count (first pixels)) size)
        rows (quot (count pixels) size)]
    (->> pixels
         (mapv (fn [row]
                 (->> row
                      (partition-all cols cols)
                      (mapv #(apply + %)))))
         (partition-all rows rows)
         (mapv #(->> % (apply mapv +) make-px)))))