Piccolo2D Hello World with pan and zoom

;  This is the canonical Hello World program for the Piccolo2D structured 2D
;  graphics framework. You can find the original Java program at
;
;  http://www.piccolo2d.org/learn/patterns.html
; 
;  This program creates a Swing window that displays the phrase "Hello World"
;  as a pNode object. You can:
; 
;  * pan the underlying canvas by holding down the LEFT mouse button while the
;   pointer is anywhere within the window
; 
;  * zoom in or zoom out of the underlying canvas by holding down the RIGHT
;    mouse button AND moving the mouse pointer right or left

(ns piccoloHello
 (:gen-class)
 (:import (edu.umd.cs.piccolo PCanvas PNode PLayer)
   (edu.umd.cs.piccolo.nodes PText)
   (edu.umd.cs.piccolox PFrame)))

(defn create-frame
  "Creates the main PFrame used by the program."
  []
  (proxy [PFrame] []
    (initialize []
      (let [aNode (PText. "Hello World")]
        (.. this getCanvas getLayer (addChild aNode))))))

(defn -main []
  (let [main-frame (create-frame)]
    (.setVisible main-frame true)))