24 lines
932 B
Clojure
24 lines
932 B
Clojure
(defn draw-line
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"Draw a line from x1,y1 to x2,y2 using Bresenham's, to a java BufferedImage in the colour of pixel."
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[buffer x1 y1 x2 y2 pixel]
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(let [dist-x (Math/abs (- x1 x2))
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dist-y (Math/abs (- y1 y2))
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steep (> dist-y dist-x)]
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(let [[x1 y1 x2 y2] (if steep [y1 x1 y2 x2] [x1 y1 x2 y2])]
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(let [[x1 y1 x2 y2] (if (> x1 x2) [x2 y2 x1 y1] [x1 y1 x2 y2])]
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(let [delta-x (- x2 x1)
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delta-y (Math/abs (- y1 y2))
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y-step (if (< y1 y2) 1 -1)]
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(let [plot (if steep
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#(.setRGB buffer (int %1) (int %2) pixel)
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#(.setRGB buffer (int %2) (int %1) pixel))]
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(loop [x x1 y y1 error (Math/floor (/ delta-x 2)) ]
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(plot x y)
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(if (< x x2)
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; Rather then rebind error, test that it is less than delta-y rather than zero
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(if (< error delta-y)
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(recur (inc x) (+ y y-step) (+ error (- delta-x delta-y)))
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(recur (inc x) y (- error delta-y)))))))))))
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