Archimedean spiral: Difference between revisions
→{{header|Clojure}}
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(view (parametric-plot arq-spiral 0 (* 10 Math/PI)))
</syntaxhighlight>
Another version inspired by the Java below, showing how to interop with awt/swing to do simple graphics:
<syntaxhighlight lang="clojure">
(let [panel (proxy [javax.swing.JPanel] []
(paintComponent [g]
(proxy-super paintComponent g)
(.setStroke g (java.awt.BasicStroke. 2))
(.setRenderingHint g java.awt.RenderingHints/KEY_ANTIALIASING
java.awt.RenderingHints/VALUE_ANTIALIAS_ON)
(let [[a b] [0 (/ 1 Math/PI)]
[w h] [(.getWidth this) (.getHeight this)]
[cx cy] [(/ w 2.0) (/ h 2.0)]
margin 16
[rotations point-n] [3 (quot (min w h) 2)]
[ring-n line-n] [6 12]
scale (/ (- (min w h) (* 2 margin)) (* 2.0 ring-n))]
;; Grid
(.setColor g (java.awt.Color. 0xEEEEEE))
(doseq [i (range 1 (inc ring-n))]
(let [[posx posy] [(- cx (* i scale)) (- cy (* i scale))]]
(.drawOval g posx posy (* 2 i scale) (* 2 i scale))))
(dotimes [i line-n]
(let [theta (* 2 Math/PI (/ i (double line-n)))
[x y] [(+ cx (* scale ring-n (Math/cos theta)))
(+ cy (* scale ring-n (Math/sin theta)))]]
(.drawLine g cx cy x y)))
;; Spiral
(.setColor g (java.awt.Color. 0x202020))
(loop [i 0 [x y] [(+ cx (* a scale)) cy]]
(let [p (/ (inc i) (double point-n))
theta (* rotations 2 Math/PI p)
r (* scale (+ a (* b theta)))
[x1 y1] [(+ cx (* r (Math/cos theta)))
(- cy (* r (Math/sin theta)))]]
(.drawLine g x y x1 y1)
(when (< i (dec point-n)) (recur (inc i) [x1 y1])))))))]
(doto (javax.swing.JFrame.)
(.add (doto panel
(.setPreferredSize (java.awt.Dimension. 640 640))
(.setBackground java.awt.Color/white))
java.awt.BorderLayout/CENTER)
(.pack)
(.setVisible true)))
</syntaxhighlight>
=={{header|Common Lisp}}==
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