pointns.clj

(defn points [^BufferedImage image ^BufferedImage screen]
  (let [width (.getWidth image)
        height (.getHeight image)
        xrange (range width)
        yrange (range height)]
    (for [points
          (for [sx (range (- (.getWidth screen) width))
                sy (range (- (.getHeight screen) height))]
            (for [tx xrange
                  ty yrange]
              [sx sy tx ty]))
          :when (every? (fn [[sx sy tx ty]]
                          (= (.getRGB screen (+ sx tx) (+ sy ty))
                             (.getRGB image tx ty)))
                        points)
          [x y _ _] points]
      [(+ x (/ width 2)) (+ y (/ height 2))])))