Add logic to Element#getStyle in Opera that fixes inaccurate reporting of computed 'width' and 'height' properties. [Andrew Dupont]

CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Add logic to Element#getStyle in Opera that fixes inaccurate reporting of computed 'width' and 'height' properties. [Andrew Dupont]
+
 * Ensure that an Ajax.Request's parameters option can be a Hash.  Closes #10172.  [kangax, sam] 
 
 * Ensure no comment nodes are returned in Selector queries (IE improperly returns comment nodes on getElementsByTagName("*")). Change Element#descendants to use Element#getElementsBySelector in order to avoid this issue. Closes #10220. [Jeff Gobel, Andrew Dupont]

src/dom.js

@@ -705,22 +705,46 @@ if (!document.createRange || Prototype.Browser.Opera) {
 }
 
 if (Prototype.Browser.Opera) { 
-  Element.Methods._getStyle = Element.Methods.getStyle; 
-  Element.Methods.getStyle = function(element, style) { 
-    switch(style) { 
-      case 'left': 
-      case 'top': 
-      case 'right': 
-      case 'bottom': 
-        if (Element._getStyle(element, 'position') == 'static') return null; 
-      default: return Element._getStyle(element, style); 
+  Element.Methods.getStyle = Element.Methods.getStyle.wrap( 
+    function(proceed, element, style) {
+      switch (style) {
+        case 'left': case 'top': case 'right': case 'bottom':
+          if (proceed(element, 'position') === 'static') return null;
+        case 'height': case 'width':
+          // returns '0px' for hidden elements; we want it to return null
+          if (!Element.visible(element)) return null;
+          
+          // returns the border-box dimensions rather than the content-box
+          // dimensions, so we subtract padding and borders from the value
+          var dim = parseInt(proceed(element, style), 10);
+          
+          if (dim !== element['offset' + style.capitalize()])
+            return dim + 'px';
+            
+          var properties;
+          if (style === 'height') {
+            properties = ['border-top-width', 'padding-top',
+             'padding-bottom', 'border-bottom-width'];
+          }
+          else {
+            properties = ['border-left-width', 'padding-left',
+             'padding-right', 'border-right-width'];            
+          }             
+          return properties.inject(dim, function(memo, property) {
+            var val = proceed(element, property);
+            return val === null ? memo : memo - parseInt(val, 10);              
+          }) + 'px';          
+        default: return proceed(element, style);
+      }
     }
-  };
-  Element.Methods._readAttribute = Element.Methods.readAttribute; 
-  Element.Methods.readAttribute = function(element, attribute) { 
-    if (attribute == 'title') return element.title; 
-    return Element._readAttribute(element, attribute);
-  };  
+  );
+  
+  Element.Methods.readAttribute = Element.Methods.readAttribute.wrap(
+    function(proceed, element, attribute) {
+      if (attribute === 'title') return element.title;
+      return proceed(element, attribute);
+    }
+  );  
 }
 
 else if (Prototype.Browser.IE) {
@@ -891,7 +915,7 @@ else if (Prototype.Browser.WebKit) {
   };
   
   // Safari returns margins on body which is incorrect if the child is absolutely
-  // positioned.  For performance reasons, redefine Position.cumulativeOffset for
+  // positioned.  For performance reasons, redefine Element#cumulativeOffset for
   // KHTML/WebKit only.
   Element.Methods.cumulativeOffset = function(element) {
     var valueT = 0, valueL = 0;
@@ -1049,7 +1073,7 @@ if (!Prototype.BrowserFeatures.ElementExtensions &&
 Element.extend = (function() {
   if (Prototype.BrowserFeatures.SpecificElementExtensions)
     return Prototype.K;
-  
+
   var Methods = { }, ByTag = Element.Methods.ByTag;
   
   var extend = Object.extend(function(element) {