38 lines
1.3 KiB
Clojure
38 lines
1.3 KiB
Clojure
(import '[java.io File]
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'[javax.imageio ImageIO]
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'[java.awt Color]
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'[java.awt.image BufferedImage]))
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(defn rgb-to-gray [color-image]
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(let [width (.getWidth color-image)]
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(partition width
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(for [x (range width)
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y (range (.getHeight color-image))]
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(let [rgb (.getRGB color-image x y)
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rgb-object (new Color rgb)
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r (.getRed rgb-object)
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g (.getGreen rgb-object)
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b (.getBlue rgb-object)
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a (.getAlpha rgb-object)]
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;Compute the grayscale value an return it: L = 0.2126·R + 0.7152·G + 0.0722·B
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(+ (* r 0.2126) (* g 0.7152) (* b 0.0722)))))))
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(defn write-matrix-to-image [matrix filename]
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(ImageIO/write
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(let [height (count matrix)
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width (count (first matrix))
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output-image (new BufferedImage width height BufferedImage/TYPE_BYTE_GRAY)]
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(doseq [row-index (range height)
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column-index (range width)]
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(.setRGB output-image column-index row-index (.intValue (nth (nth matrix row-index) column-index))))
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output-image)
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"png"
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(new File filename)))
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(println
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(write-matrix-to-image
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(rgb-to-gray
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(ImageIO/read (new File "test.jpg")))
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"test-gray-cloj.png"))
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