Wednesday, February 17

Capturing a screenshot, displaying an image, and load/saving an image in Clojure

The following functions perform a screenshot, or capture a region of the screen, and then provide a method to display the captured image in a new window or load/save to disk.

Note: I'd like to thank hoeck (from the Clojure IRC channel) for writing the display-image function.

(defn display-image
"Displays an image in a new window"
(let [frame (doto (javax.swing.JFrame. "Display Image")
(.setBounds 0 0 (. image getWidth) (. image getHeight))
(.setVisible true))
cv (proxy [java.awt.Canvas] []
(paint [g] (. g drawImage image nil nil))
(update [g] (. g drawImage image nil nil)))]
(.add (.getContentPane frame) cv)))

(defn capture-image
"Captures an image of a section of the primary screen"
[from-x from-y x-size y-size]
(let [rob (java.awt.Robot.)
rect (java.awt.Rectangle. from-x from-y x-size y-size)]
(. rob createScreenCapture rect)))

(defn grab-screen
"Returns an image of the entire primary screen"
(let [my-scr (.. java.awt.Toolkit (getDefaultToolkit) (getScreenSize))]
(capture-image 0 0 (. my-scr width) (. my-scr height))))

(defn save-image
"Save an image to disk as jpg"
[image filename]
(javax.imageio.ImageIO/write image "jpg" ( filename))

(defn load-image
"Read a jpg from disk"
(javax.imageio.ImageIO/read ( filename)))

A Change of direction

With my last post about Japan at least a year old now, I've decided to use this space as a giant notepad for my other interests and pursuits.

For the time being this means I'll start posting again but mainly with the discussion relating to software engineering, code snippets, and interesting math.