;;; File:
;;;   list-recursion-revisited-lab.scm
;;; Authors:
;;;   Janet Davis
;;;   Samuel A. Rebelsky
;;;   Jerod Weinman
;;;   YOUR NAME HERE
;;; Summary:
;;;   Code for the lab entitled "List Recursion, Revisited"

; +-----------------+-----------------------------------------------------------
; | Color Utilities |
; +-----------------+

;;; Procedure:
;;;   rgb-brightness
;;; Parameters:
;;;   color, an RGB color
;;; Purpose:
;;;   Computes the brightness of color on a 0 (dark) to 100 (light) scale.
;;; Produces:
;;;   b, an integer
;;; Preconditions:
;;;   color is a valid RGB color.  That is, each component is between
;;;     0 and 255, inclusive.
;;; Postconditions:
;;;   If color1 is likely to be perceived as lighter than color2,
;;;     then (brightness color1) > (brightness color2).
;;;   0 <= b <= 100
(define rgb-brightness
  (lambda (color)
    (round (* 100 (/ (+ (* 0.30 (rgb-red color))
                        (* 0.59 (rgb-green color))
                        (* 0.11 (rgb-blue color)))
                      255)))))

;;; Procedure:
;;;   rgb-brighter
;;; Parameters:
;;;   color1, an RGB color.
;;;   color2, an RGB color.
;;; Purpose:
;;;   Find the brighter of color1 and color2.
;;; Produces:
;;;   brighter, an RGB color.
;;; Preconditions:
;;;   [No additional]
;;; Postconditions:
;;;   brighter is either color1 or color2
;;;   (rgb-brightness brighter) >= (rgb-brightness color1)
;;;   (rgb-brightness brighter) >= (rgb-brightness color2)
(define rgb-brighter
  (lambda (color1 color2)
    (if (>= (rgb-brightness color1) (rgb-brightness color2))
        color1
        color2)))

;;; Procedure:
;;;   rgb-bright?
;;; Parameters:
;;;   color, an RGB color
;;; Purpose:
;;;   Determines whether the color is bright.
;;; Produces:
;;;   bright?, a boolean
;;; Preconditions:
;;;   color is a valid RGB color.  That is, each component is between
;;;     0 and 255, inclusive.
;;;   rgb-brightness is defined.
;;; Postconditions:
;;;   bright? is true iff (rgb-brightness color) >= 67.
(define rgb-bright?
  (lambda (color)
    (<= 67 (rgb-brightness color))))

; +-------------+---------------------------------------------------------------
; | Some Colors |
; +-------------+

(define my-color-names 
  (list "palevioletred" "cadetblue" "darkseagreen" "goldenrod"
        "hotpink" "lightsteelblue" "burlywood" "mistyrose"
        "salmon" "peru" "plum" "turquoise"))
(define my-colors
  (map color-name->rgb my-color-names))

(define green-names (context-list-colors "green"))

(define greens (map color->rgb green-names))

(define greys-4
  (map (lambda (n) (rgb-new (* 64 n) (* 64 n) (* 64 n)))
       (list 4 3 2 1)))
(define greys-8
  (map (lambda (n) (rgb-new (* 32 n) (* 32 n) (* 32 n)))
       (list 8 7 6 5 4 3 2 1)))
(define greys-16
  (map (lambda (n) (rgb-new (* 16 n) (* 16 n) (* 16 n)))
       (list 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1)))