Fix #37: Ensure that the calculated viewport width is always even numbered

js/views/reflowable_view.js

@@ -445,6 +445,12 @@ var ReflowableView = function(options, reader){
     function updateViewportSize() {
 
         var newWidth = _$contentFrame.width();
+
+        // Ensure that the new viewport width is always even numbered
+        // this is to prevent a rendering inconsistency between browsers when odd-numbered bounds are used for CSS columns
+        // See https://github.com/readium/readium-shared-js/issues/37
+        newWidth -= newWidth % 2;
+
         var newHeight = _$contentFrame.height();
 
         if(_lastViewPortSize.width !== newWidth || _lastViewPortSize.height !== newHeight){