add clojure functions for loading an image and converting to ascii

src/clojure/clj_image2ascii/core.clj

@@ -1,6 +1,62 @@
-(ns clj-image2ascii.core)
+(ns clj-image2ascii.core
+  (:import (javax.imageio ImageIO)
+           (java.awt.image BufferedImage)
+           (java.net URL)
+           (java.io File)
+           (java.awt RenderingHints Graphics2D)
+           (clj_image2ascii.java ImageToAscii)))
 
-(defn foo
-  "I don't do a whole lot."
-  [x]
-  (println x "Hello, World!"))
+(defn get-image-by-url
+  "returns a BufferedImage loaded from the URL specified, or null if an error occurs"
+  (^BufferedImage [^URL url]
+   (try
+     (ImageIO/read url)
+     (catch Exception ex))))
+
+(defn get-image-by-file
+  "returns a BufferedImage loaded from the file specified, or null if an error occurs"
+  (^BufferedImage [^File file]
+   (try
+     (ImageIO/read file)
+     (catch Exception ex))))
+
+(defn scale-image
+  "takes a source BufferedImage and scales it proportionally using the new width,
+   returning the scaled image as a new BufferedImage"
+  (^BufferedImage [^BufferedImage image new-width]
+   (let [new-height   (* (/ new-width (.getWidth image))
+                         (.getHeight image))
+         scaled-image (BufferedImage. new-width new-height BufferedImage/TYPE_INT_RGB)
+         gfx2d        (doto (.createGraphics scaled-image)
+                        (.setRenderingHint RenderingHints/KEY_INTERPOLATION
+                                           RenderingHints/VALUE_INTERPOLATION_BILINEAR)
+                        (.drawImage image 0 0 new-width new-height nil)
+                        (.dispose))]
+     scaled-image)))
+
+(defn convert-image
+  "converts a BufferedImage to an ASCII representation. scale-to-width is a new width
+   in pixels to scale the image to, if specified. the scaling will be done such that
+   the entire image is scaled proportionally and is done before the ASCII conversion
+   is performed. the return value is a map containing:
+
+   :width  - the width in pixels of the image that was converted
+   :height - the height in pixels of the image that was converted
+   :color? - indicates if the ASCII includes color information or not
+   :image  - a string containing the image's ASCII representation. if color? is true,
+             then this string will include HTML <span> tags wrapping each individual
+             ASCII character with <br> tags between each line of 'pixels'. if false,
+             then only the raw characters are included, with newline characters
+             between each line of 'pixels'."
+  ([^BufferedImage image color?]
+   (convert-image image nil color?))
+  ([^BufferedImage image scale-to-width color?]
+   (let [current-width (.getWidth image)
+         new-width     (or scale-to-width current-width)
+         final-image   (if-not (= new-width current-width)
+                         (scale-image image new-width)
+                         image)]
+     {:width  (.getWidth final-image)
+      :height (.getHeight final-image)
+      :color? (if color? true false)   ; forcing an explicit true/false because i am nitpicky like that
+      :image  (ImageToAscii/convert final-image color?)})))