cgc.clj

(require '[thi.ng.color.core :as col]))

(defn cosine-coeficients
  "amp = (R1-R2) / 2; dc offset = R1-amp; freq = -0.5"
  ([h1 h2]
   (let [coerce #(col/as-rgba (col/hex->int %))
         colors (->> [(coerce h1) (coerce h2)]
                     (map #(select-keys % [:r :g :b])))
         [c1 _] colors
         
         amp (->> colors
                  (apply
                   mapv (fn [[_ v1] [_ v2]]
                          (* 0.5 (- v1 v2)))))

         offset (->> amp
                     (mapv (fn [[_ v1] a]
                             (- v1 a))
                           c1))]

     [offset amp
      [-0.500 -0.500 -0.500]
      [0.000 0.000 0.000]])))