adjusted CSS column algorithm in reflowable view to take into account…

… single-column vertical writing mode (user setting has no effect, max text width corresponds 2x single-column threshold)

js/views/reflowable_view.js

@@ -497,11 +497,15 @@ ReadiumSDK.Views.ReflowableView = function(options, reader){
 
 
     function updatePagination() {
-
+
+        // At 100% font-size = 16px (on HTML, not body or descendant markup!)
+        var MAXW = 550; //TODO user/vendor-configurable?
+        var MINW = 400;
+
         var isDoublePageSyntheticSpread = ReadiumSDK.Helpers.deduceSyntheticSpread(_$viewport, _currentSpineItem, _viewSettings);
 
         var forced = (isDoublePageSyntheticSpread === false) || (isDoublePageSyntheticSpread === true);
-        // excludes 0 and 1 truthy values which denote non-forced result
+        // excludes 0 and 1 falsy/truthy values which denote non-forced result
 
 // console.debug("isDoublePageSyntheticSpread: " + isDoublePageSyntheticSpread);
 // console.debug("forced: " + forced);
@@ -512,8 +516,17 @@ ReadiumSDK.Views.ReflowableView = function(options, reader){
 // console.debug("TRYING SPREAD INSTEAD OF SINGLE...");
         }
 
-        _paginationInfo.visibleColumnCount = _htmlBodyIsVerticalWritingMode ? 1 : (isDoublePageSyntheticSpread ? 2 : 1);
+        _paginationInfo.visibleColumnCount = isDoublePageSyntheticSpread ? 2 : 1;
 
+        if (_htmlBodyIsVerticalWritingMode)
+        {
+            MAXW *= 2;
+            isDoublePageSyntheticSpread = false;
+            forced = true;
+            _paginationInfo.visibleColumnCount = 1;
+// console.debug("Vertical Writing Mode => single CSS column, but behaves as if two-page spread");
+        }
+
         if(!_$epubHtml) {
             return;
         }
@@ -529,10 +542,6 @@ ReadiumSDK.Views.ReflowableView = function(options, reader){
 
         var filler = 0;
 
-        // At 100% font-size = 16px (on HTML, not body or descendant markup!)
-        var MAXW = 550; //TODO user/vendor-configurable?
-        var MINW = 400;
-
 //         var win = _$iframe[0].contentDocument.defaultView || _$iframe[0].contentWindow;
 //         var htmlBodyComputedStyle = win.getComputedStyle(_$htmlBody[0], null);
 //         if (htmlBodyComputedStyle)