ronin/PRELUDE.md

Prelude

Colors

Compare two Colors

Use: (if (color-eq (255 200 0) (200 255 0)) "yes" "no").

(defn color-eq 
  (a b) 
  (and 
    (eq a:0 b:0) 
    (eq a:1 b:1) 
    (eq a:2 b:2)))

Pixels

Erase all pixels of a specific color

Use: (pixels erase-color (255 0 0)).

(defn erase-color 
  (a b) 
  (a:0 a:1 a:2 
    (if 
      (and 
        (eq a:0 b:0) 
        (eq a:1 b:1) 
        (eq a:2 b:2)) 0 255)))

Posterize

Use: (pixels posterize 40).

(defn posterize 
  (a q) 
  (
    (step a:0 q) 
    (step a:1 q) 
    (step a:2 q) a:3))