CLJS Flower

(setf #j:canvas (#j:document:getElementById "canvas")
      #j:ctx (#j:canvas:getContext "2d"))

(defun to-radix (var radix)
  ((jscl::oget var "toString") radix))

(defun random-hex ()
  (to-radix (random 15) 16))

(defun get-random-colour ()
  (concatenate 'string
    "#"
    (loop for _ below 6 collect (random-hex))))

(defvar step-scale 0.99)
(defconstant +PI+ #j:Math:PI)

(defun render-leaflet (rotation)
 (#j:ctx:scale step-scale step-scale)
 (#j:ctx:rotate rotation)
 (#j:ctx:beginPath)
 (#j:ctx:arc 0 50 50 (/ (- +PI+) 2) 0)
 (setf #j:ctx:fillStyle "#000")
 (#j:ctx:fill)
 (#j:ctx:beginPath)
 (#j:ctx:arc 50 0 50 (- +PI+) (/ +PI+ 2) t)
 (setf #j:ctx:fillStyle (get-random-colour))
 (#j:ctx:fill))

(setf #j:ctx:canvas:width #j:window:innerWidth
      #j:ctx:canvas:height #j:window:innerWidth)

(#j:ctx:translate
  (/ #j:window:innerWidth 2)
  (/ #j:window:innerWidth 2))
(#j:ctx:scale 5 5)

(#j:setInterval
  (let ((i 0))
    (lambda ()
      (format t "Rendering ~a~%" i)
      (render-leaflet (/ (incf i) 50))))
  50))