(define-module (output general)
  )

;; Returns a color with good contrast to the given background color.
(define-public (calculate-fg-color c)
  (define (str->num c n) (string->number (substring/shared c n (+ n 2)) 16))
  (let ((r (str->num c 1))
        (g (str->num c 3))
        (b (str->num c 5)))
    (if (< 1/2 (/ (+ (* 0.299 r)
                     (* 0.587 g)
                     (* 0.144 b))
                  #xFF))
        "#000000" "#e5e8e6")))