Modify rectangle-based visibility detection so it supports vertical w…

…riting mode.

js/views/cfi_navigation_logic.js

@@ -61,15 +61,30 @@ ReadiumSDK.Views.CfiNavigationLogic = function($viewport, $iframe, options){
         return options.paginationInfo && !!options.paginationInfo.rightToLeft;
     }
 
+    /**
+     * @private
+     * Checks whether or not pages are rendered with vertical writing mode
+     *
+     * @returns {boolean}
+     */
+    function isVerticalWritingMode() {
+        return options.paginationInfo && !!options.paginationInfo.isVerticalWritingMode;
+    }
+
+
     /**
      * @private
      * Checks whether or not a (fully adjusted) rectangle is at least partly visible
      *
      * @param {Object} rect
      * @param {Object} frameDimensions
+     * @param {boolean} [isVwm]           isVerticalWritingMode
      * @returns {boolean}
      */
-    function isRectVisible(rect, frameDimensions) {
+    function isRectVisible(rect, frameDimensions, isVwm) {
+        if (isVwm) {
+            return rect.top >= 0 && rect.top < frameDimensions.height;
+        }
         return rect.left >= 0 && rect.left < frameDimensions.width;
     }
 
@@ -81,7 +96,7 @@ ReadiumSDK.Views.CfiNavigationLogic = function($viewport, $iframe, options){
      */
     function getColumnFullWidth() {
 
-        if (!options.paginationInfo || options.paginationInfo.isVerticalWritingMode)
+        if (!options.paginationInfo || isVerticalWritingMode())
         {
             return $iframe.width();
         }
@@ -169,6 +184,7 @@ ReadiumSDK.Views.CfiNavigationLogic = function($viewport, $iframe, options){
         }
 
         var isRtl = isPageProgressionRightToLeft();
+        var isVwm = isVerticalWritingMode();
         var columnFullWidth = getColumnFullWidth();
         var frameDimensions = {
             width: $iframe.width(),
@@ -179,15 +195,15 @@ ReadiumSDK.Views.CfiNavigationLogic = function($viewport, $iframe, options){
             // because of webkit inconsistency, that single rectangle should be adjusted
             // until it hits the end OR will be based on the FIRST column that is visible
             adjustRectangle(clientRectangles[0], frameDimensions, columnFullWidth,
-                    isRtl, true);
+                    isRtl, isVwm, true);
         }
 
         // for an element split between several CSS columns,
         // both Firefox and IE produce as many client rectangles;
         // each of those should be checked
         var visibilityPercentage = 0;
         for (var i = 0, l = clientRectangles.length; i < l; ++i) {
-            if (isRectVisible(clientRectangles[i], frameDimensions)) {
+            if (isRectVisible(clientRectangles[i], frameDimensions, isVwm)) {
                 visibilityPercentage = shouldCalculateVisibilityPercentage
                     ? measureVisibilityPercentageByRectangles(clientRectangles, i)
                     : 100;
@@ -387,13 +403,20 @@ ReadiumSDK.Views.CfiNavigationLogic = function($viewport, $iframe, options){
      * @param {Object} frameDimensions
      * @param {number} columnFullWidth
      * @param {boolean} isRtl
+     * @param {boolean} isVwm               isVerticalWritingMode
      * @param {boolean} shouldLookForFirstVisibleColumn
      *      If set, there'll be two-phase adjustment
      *      (to align a rectangle with a viewport)
+
      */
-    function adjustRectangle(rect, frameDimensions, columnFullWidth, isRtl,
+    function adjustRectangle(rect, frameDimensions, columnFullWidth, isRtl, isVwm,
             shouldLookForFirstVisibleColumn) {
 
+        // Rectangle adjustment is not needed in VWM since it does not deal with columns
+        if (isVwm) {
+            return;
+        }
+
         if (isRtl) {
             columnFullWidth *= -1; // horizontal shifts are reverted in RTL mode
         }
@@ -409,7 +432,7 @@ ReadiumSDK.Views.CfiNavigationLogic = function($viewport, $iframe, options){
         // (i.e., is the first visible one).
         if (shouldLookForFirstVisibleColumn) {
             while (rect.bottom >= frameDimensions.height) {
-                if (isRectVisible(rect, frameDimensions)) {
+                if (isRectVisible(rect, frameDimensions, isVwm)) {
                     break;
                 }
                 offsetRectangle(rect, columnFullWidth, -frameDimensions.height);
@@ -426,9 +449,15 @@ ReadiumSDK.Views.CfiNavigationLogic = function($viewport, $iframe, options){
      * @param {number} frameHeight
      * @param {number} columnFullWidth
      * @param {boolean} isRtl
+     * @param {boolean} isVwm               isVerticalWritingMode
      */
     function trimRectanglesByVertOffset(
-            rects, verticalOffset, frameHeight, columnFullWidth, isRtl) {
+            rects, verticalOffset, frameHeight, columnFullWidth, isRtl, isVwm) {
+
+        //TODO: Support vertical writing mode
+        if (isVwm) {
+            return;
+        }
 
         var totalHeight = _.reduce(rects, function(prev, cur) {
             return prev + cur.height;