attempts to refactor / speed up image -> ascii conversion. improve image route

src/toascii/models/image.clj

@@ -11,17 +11,25 @@
   (:use hiccup.core))
 
 (def ascii-chars [\# \A \@ \% \$ \+ \= \* \: \, \. \space])
+(def num-ascii-chars (count ascii-chars))
 
-(defmacro get-properties [obj & properties]
+(defn get-image-by-url
-  (let [target (gensym)]
+  (^BufferedImage [^String url]
-    `(let [~target ~obj]
+   (try
-       (vector ~@(for [property properties]
+     (let [java-url (query-param-url->java-url url)]
-                   `(~property ~target))))))
+       (ImageIO/read java-url))
+     (catch Exception ex))))
+
+(defn get-image-by-file
+  (^BufferedImage [^File file]
+   (try
+     (ImageIO/read file)
+     (catch Exception ex))))
 
 (defn scale-image
   "takes a source image specified by the uri (a filename or a URL) and scales it proportionally
    using the new width, returning the newly scaled image."
-  [url new-width]
+  (^BufferedImage [url new-width]
    (let [^Image image (ImageIO/read url)
          new-height    (* (/ new-width (.getWidth image))
                           (.getHeight image))
@@ -31,32 +39,54 @@
                                            RenderingHints/VALUE_INTERPOLATION_BILINEAR)
                         (.drawImage image 0 0 new-width new-height nil)
                         (.dispose))]
-    scaled-image))
+     scaled-image)))
 
-(defn ascii [^BufferedImage img x y color?]
+(defn- get-css-color-attr [r g b]
-  (let [[red green blue] (get-properties (Color. (.getRGB img x y))
+  (format "color: #%02x%02x%02x;" r g b))
-                                         .getRed .getGreen .getBlue)
+
-        peak    (apply max [red green blue])
+(defn- get-pixel [^BufferedImage image x y]
-        idx     (if (zero? peak)
+  (let [argb (.getRGB image x y)]
-                  (dec (count ascii-chars))
+    [(bit-shift-right (bit-and 0xff000000 argb) 24)
-                  (dec (int (+ 1/2 (* (count ascii-chars) (/ peak 255))))))
+     (bit-shift-right (bit-and 0x00ff0000 argb) 16)
-        output  (nth ascii-chars (if (pos? idx) idx 0))	]
+     (bit-shift-right (bit-and 0x0000ff00 argb) 8)
+     (bit-and 0x000000ff argb)]))
+
+(defn get-ascii-pixel
+  ""
+  [^BufferedImage image x y color?]
+  (let [[a r g b]  (get-pixel image x y)
+        peak       (apply max [r g b])
+        char-index (if (zero? peak)
+                     (dec num-ascii-chars)
+                     (dec (int (+ 0.5 (* num-ascii-chars (/ peak 255))))))
+        pixel-char (nth ascii-chars (if (pos? char-index) char-index 0))]
     (if color?
-      (html [:span {:style (format "color: rgb(%s,%s,%s);" red green blue)} output])
+      [:span {:style (get-css-color-attr r g b)} pixel-char]
+      pixel-char)))
+
+(defn- pixels->ascii [^BufferedImage image color?]
+  (let [width       (.getWidth image)
+        ascii-image (for [y (range (.getHeight image))
+                          x (range (.getWidth image))]
+                      (get-ascii-pixel image x y color?))
+        output      (->> ascii-image
+                         (partition width)
+                         (map #(conj % (if color? [:br] \newline)))
+                         (apply concat))]
+    (if color?
+      (html
+        [:pre
+         {:style "font-size:5pt; letter-spacing:1px; line-height:4pt; font-weight:bold;"}
+         output])
       output)))
 
-(defn convert-image [url w color?]
+(defn convert-image
-  (let [java-url         (query-param-url->java-url url)
+  ([^BufferedImage image color?]
-        ^Image raw-image (scale-image java-url w)
+   (convert-image image nil color?))
-        ascii-image      (->> (for [y (range (.getHeight raw-image))
+  ([^BufferedImage image scale-width color?]
-                                    x (range (.getWidth  raw-image))]
+   (let [current-width (.getWidth image)
-                                (ascii raw-image x y color?))
+         new-width     (or scale-width current-width)
-                              (partition w))
+         final-image   (if-not (= new-width current-width)
-        output           (->> ascii-image
+                         (scale-image image new-width)
-                              (interpose (if color? "<BR/>" \newline))
+                         image)]
-                              flatten)]
+     (pixels->ascii final-image color?))))
-    (if color?
-      (html [:pre {:style "font-size:5pt; letter-spacing:1px;
-                           line-height:4pt; font-weight:bold;"}
-             output])
-      (println output))))

src/toascii/routes/api/image.clj

@@ -1,9 +1,10 @@
 (ns toascii.routes.api.image
+  (:import (java.awt.image BufferedImage))
   (:require [clojure.string :as str]
             [liberator.core :refer [defresource]]
             [compojure.core :refer [ANY]]
             [toascii.route-utils :refer [register-routes]]
-            [toascii.models.image :refer [convert-image]]))
+            [toascii.models.image :refer [convert-image get-image-by-url]]))
 
 (defresource render-image [{:keys [url width color format] :as params}]
   :media-type-available?
@@ -17,13 +18,21 @@
   (fn [_]
     (cond
       (str/blank? url) {:error "Missing image url"}))
+  :exists?
+  (fn [_]
+    (if-let [image (get-image-by-url url)]
+      {:image image}
+      [false {:error "Image could not be loaded."}]))
   :handle-ok
   (fn [ctx]
-    (let [rendered (convert-image url 64 true)]
+    (let [rendered (convert-image (:image ctx) true)]
       (if (= "text/html" (get-in ctx [:representation :media-type]))
         rendered
         rendered)))
   :handle-malformed
+  (fn [ctx]
+    (:error ctx))
+  :handle-not-found
   (fn [ctx]
     (:error ctx)))