Replace $w with split(' ') (to remove dependency on global, non-descriptive variable and Prototype in general). Add few missing console.warn statements when double initialization is attempted.

src/canvas_circle.class.js

@@ -72,7 +72,7 @@
   /**
    * @see: http://www.w3.org/TR/SVG/shapes.html#CircleElement
    */
-  Canvas.Circle.ATTRIBUTE_NAMES = $w('cx cy r fill fill-opacity stroke stroke-width transform');
+  Canvas.Circle.ATTRIBUTE_NAMES = 'cx cy r fill fill-opacity stroke stroke-width transform'.split(' ');
   
   /**
    * @static

src/canvas_element.class.js

@@ -10,6 +10,7 @@
       Canvas = global.Canvas || (global.Canvas = { });
       
   if (Canvas.Element) {
+    console.warn('Canvas.Element is already defined.');
     return;
   }
   
@@ -44,8 +45,8 @@
     if (!el.getContext) {
       return;
     }
-    var ctx = el.getContext('2d');
     
+    var ctx = el.getContext('2d');
     if (!ctx) {
       return;
     }

src/canvas_ellipse.class.js

@@ -80,7 +80,7 @@
     }
   });
   
-  Canvas.Ellipse.ATTRIBUTE_NAMES = $w('cx cy rx ry fill fill-opacity stroke stroke-width transform');
+  Canvas.Ellipse.ATTRIBUTE_NAMES = 'cx cy rx ry fill fill-opacity stroke stroke-width transform'.split(' ');
   
   /**
    * @static

src/canvas_image.class.js

@@ -102,7 +102,7 @@
       return { 
         width: element.width, 
         height: element.height
-      }
+      };
     },
     
     /**
@@ -178,7 +178,9 @@
      */
     toGrayscale: function(callback) {
       
-      if (this.__isGrayscaled) return;
+      if (this.__isGrayscaled) {
+        return;
+      }
       
       var imgEl = this.getElement(),
           canvasEl = document.createElement('canvas'),
@@ -304,8 +306,9 @@
    * @static
    */
   Canvas.Image.fromObject = function(object, callback) {
-    var img = document.createElement('img');
-    var src = object.src;
+    var img = document.createElement('img'),
+        src = object.src;
+        
     if (object.width) {
       img.width = object.width;
     }
@@ -317,7 +320,7 @@
         callback(new Canvas.Image(img, object));
       }
       img = img.onload = null;
-    }
+    };
     img.src = src;
   };
   

src/canvas_line.class.js

@@ -70,7 +70,7 @@
   });
   
   // http://www.w3.org/TR/SVG/shapes.html#LineElement
-  Canvas.Element.ATTRIBUTE_NAMES = $w('x1 y1 x2 y2 stroke stroke-width transform');
+  Canvas.Element.ATTRIBUTE_NAMES = 'x1 y1 x2 y2 stroke stroke-width transform'.split(' ');
   
   /**
    * @static

src/canvas_object.class.js

@@ -45,9 +45,9 @@
     /**
      * @field
      */
-    stateProperties: $w('top left width height scaleX scaleY flipX flipY ' +
-                        'theta angle opacity cornersize fill overlayFill stroke ' +
-                        'strokeWidth fillRule borderScaleFactor transformMatrix'),
+    stateProperties:  ('top left width height scaleX scaleY flipX flipY ' +
+                      'theta angle opacity cornersize fill overlayFill stroke ' +
+                      'strokeWidth fillRule borderScaleFactor transformMatrix').split(' '),
     
     /**
      * @field

src/canvas_path.class.js

@@ -1,15 +1,12 @@
 (function(){
   
-  var global = this;
+  var Canvas = this.Canvas || (this.Canvas = { });
   
-  if (!global.Canvas) {
-    global.Canvas = { };
-  }
-  if (global.Canvas.Path) {
+  if (Canvas.Path) {
     console.warn('Canvas.Path is already defined');
     return;
   }
-  if (!global.Canvas.Object) {
+  if (!Canvas.Object) {
     console.warn('Canvas.Path requires Canvas.Object');
     return;
   }
@@ -453,7 +450,7 @@
     return new Canvas.Path(object.path, object);
   };
   
-  var ATTRIBUTE_NAMES = Canvas.Path.ATTRIBUTE_NAMES = $w('d fill fill-opacity fill-rule stroke stroke-width transform');
+  var ATTRIBUTE_NAMES = Canvas.Path.ATTRIBUTE_NAMES = 'd fill fill-opacity fill-rule stroke stroke-width transform'.split(' ');
   /**
    * Creates an instance of Canvas.Path from an SVG <PATH> element
    * @static

src/canvas_path_group.class.js

@@ -2,6 +2,7 @@
   
   var Canvas = this.Canvas || (this.Canvas = { });
   if (Canvas.PathGroup) {
+    console.warn('Canvas.PathGroup is already defined');
     return;
   }
   

src/canvas_point.class.js

@@ -2,8 +2,7 @@
   
   /* Adaptation of work of Kevin Lindsey (kevin@kevlindev.com) */
   
-  var global = this;
-  var Canvas = global.Canvas || (global.Canvas = { });
+  var Canvas = this.Canvas || (this.Canvas = { });
 
   if (Canvas.Point) {    
     console.warn('Canvas.Point is already defined');

src/canvas_polygon.class.js

@@ -1,7 +1,9 @@
 (function(){
   
   var Canvas = this.Canvas || (this.Canvas = { });
+  
   if (Canvas.Polygon) {
+    console.warn('Canvas.Polygon is already defined');
     return;
   }
   
@@ -100,7 +102,7 @@
   });
   
   // http://www.w3.org/TR/SVG/shapes.html#PolygonElement
-  Canvas.Polygon.ATTRIBUTE_NAMES = $w('fill fill-opacity stroke stroke-width transform');
+  Canvas.Polygon.ATTRIBUTE_NAMES = 'fill fill-opacity stroke stroke-width transform'.split(' ');
   
   /**
    * @static
@@ -110,9 +112,12 @@
    * @return {Object} instance of Canvas.Polygon
    */
   Canvas.Polygon.fromElement = function(element, options) {
-    if (!element) return null;
+    if (!element) {
+      return null;
+    }
     var points = Canvas.parsePointsAttribute(element.getAttribute('points')),
         parsedAttributes = Canvas.parseAttributes(element, Canvas.Polygon.ATTRIBUTE_NAMES);
+        
     return new Canvas.Polygon(points, Object.extend(parsedAttributes, options));
   };
   

src/canvas_polyline.class.js

@@ -1,7 +1,9 @@
 (function(){
   
   var Canvas = this.Canvas || (this.Canvas = { });
+  
   if (Canvas.Polyline) {
+    console.warn('Canvas.Polyline is already defined');
     return;
   }
   
@@ -78,7 +80,7 @@
   });
   
   // http://www.w3.org/TR/SVG/shapes.html#PolylineElement
-  var ATTRIBUTE_NAMES = $w('fill fill-opacity stroke stroke-width transform');
+  var ATTRIBUTE_NAMES = 'fill fill-opacity stroke stroke-width transform'.split(' ');
   
   /**
    * @static
@@ -88,9 +90,12 @@
    * @return {Object} instance of Canvas.Polyline
    */
   Canvas.Polyline.fromElement = function(element, options) {
-    if (!element) return null;
+    if (!element) {
+      return null;
+    }
     var points = Canvas.parsePointsAttribute(element.getAttribute('points')),
         parsedAttributes = Canvas.parseAttributes(element, ATTRIBUTE_NAMES);
+        
     return new Canvas.Polyline(points, Object.extend(parsedAttributes, options));
   };
   

src/canvas_rect.class.js

@@ -96,7 +96,7 @@
   });
   
   // TODO (kangax): implement rounded rectangles (both parsing and rendering)
-  Canvas.Rect.ATTRIBUTE_NAMES = $w('x y width height rx ry fill fill-opacity stroke stroke-width transform');
+  Canvas.Rect.ATTRIBUTE_NAMES = 'x y width height rx ry fill fill-opacity stroke stroke-width transform'.split(' ');
   
   /**
    * @private
@@ -115,7 +115,10 @@
    * @return {Object} instance of Canvas.Rect
    */
   Canvas.Rect.fromElement = function(element, options) {
-    if (!element) return null;
+    if (!element) {
+      return null;
+    }
+    
     var parsedAttributes = Canvas.parseAttributes(element, Canvas.Rect.ATTRIBUTE_NAMES);
     parsedAttributes = _setDefaultLeftTopValues(parsedAttributes);
     

src/canvas_text.class.js

@@ -1,13 +1,12 @@
 (function(){
   
-  var global = this;
-  var Canvas = global.Canvas || (global.Canvas = { });
+  var Canvas = this.Canvas || (this.Canvas = { });
 
-  if (global.Canvas.Text) {    
+  if (Canvas.Text) {    
     console.warn('Canvas.Text is already defined');
     return;
   }
-  if (!global.Canvas.Object) {
+  if (!Canvas.Object) {
     console.warn('Canvas.Text requires Canvas.Object');
     return;
   }

src/canvas_util.js

@@ -3,6 +3,7 @@
   var Canvas = this.Canvas || (this.Canvas = { });
   
   if (Canvas.util) {
+    console.warn('Canvas.util is already defined');
     return;
   }
   

test/unit/canvas_object.js

@@ -143,7 +143,7 @@ function init() {
       this.assertHashEqual(augmentedObjectRepr, cObj.toObject());
       
       var fractionalValue = 166.66666666666666,
-          testedProperties = $w('left top width height'),
+          testedProperties = 'left top width height'.split(' '),
           fractionDigitsDefault = 2;
           
       function testFractionDigits(fractionDigits, expectedValue) {

test/unit/canvas_parser.js

@@ -65,7 +65,7 @@ function init() {
       this.assert(Canvas.parseAttributes);
       
       var element = makeElement();
-      var attributeNames = $w(' cx cy x y r fill-opacity fill-rule stroke-width transform fill fill-rule');
+      var attributeNames = 'cx cy x y r fill-opacity fill-rule stroke-width transform fill fill-rule'.split(' ');
       var parsedAttributes = Canvas.parseAttributes(element, attributeNames);
       
       this.assertObjectIdentical({
@@ -84,7 +84,7 @@ function init() {
       element.setAttribute('stroke', 'none');
       
       this.assertObjectIdentical({ fill: '', stroke: '' }, 
-        Canvas.parseAttributes(element, $w(' fill stroke ')));
+        Canvas.parseAttributes(element, 'fill stroke'.split(' ')));
     },
     
     testCanvasParseAttributesFillRule: function() {
@@ -92,7 +92,7 @@ function init() {
       element.setAttribute('fill-rule', 'evenodd');
       
       this.assertObjectIdentical({ fillRule: 'destination-over' }, 
-        Canvas.parseAttributes(element, $w(' fill-rule ')));
+        Canvas.parseAttributes(element, ['fill-rule']));
     },
     
     testCanvasParseAttributesFillRuleWithoutTransformation: function() {
@@ -100,14 +100,14 @@ function init() {
       element.setAttribute('fill-rule', 'inherit');
       
       this.assertObjectIdentical({ fillRule: 'inherit' }, 
-        Canvas.parseAttributes(element, $w(' fill-rule ')));
+        Canvas.parseAttributes(element, ['fill-rule']));
     },
     
     testCanvasParseAttributesTransform: function() {
       var element = document.createElement('path');
       element.setAttribute('transform', 'translate(5, 10)');
       this.assertObjectIdentical({ transformMatrix: [1, 0, 0, 1, 5, 10] }, 
-        Canvas.parseAttributes(element, $w(' transform ')));
+        Canvas.parseAttributes(element, ['transform']));
     },
     
     testCanvasParseAttributesWithParent: function() {
@@ -123,7 +123,7 @@ function init() {
       grandParent.setAttribute('fill', 'red');
       
       this.assertObjectIdentical({ fill: 'red', left: 100, top: 200 }, 
-        Canvas.parseAttributes(element, $w(' x y fill ')));
+        Canvas.parseAttributes(element, ['x y fill']));
     },
     
     testCanvasParseElements: function() {