Merge pull request #3911 from yurydelendik/mem-redux2

Cleaning up fonts when viewer is idle for some time

web/viewer.js

@@ -38,6 +38,7 @@ var SCALE_SELECT_CONTAINER_PADDING = 8;
 var SCALE_SELECT_PADDING = 22;
 var THUMBNAIL_SCROLL_MARGIN = -19;
 var USE_ONLY_CSS_ZOOM = false;
+var CLEANUP_TIMEOUT = 30000;
 //#if B2G
 //USE_ONLY_CSS_ZOOM = true;
 //#endif
@@ -106,6 +107,7 @@ var PDFView = {
   lastScroll: 0,
   previousPageNumber: 1,
   isViewerEmbedded: (window.parent !== window),
+  idleTimeout: null,
 
   // called once when the document is loaded
   initialize: function pdfViewInitialize() {
@@ -1011,6 +1013,11 @@ var PDFView = {
   },
 
   renderHighestPriority: function pdfViewRenderHighestPriority() {
+    if (PDFView.idleTimeout) {
+      clearTimeout(PDFView.idleTimeout);
+      PDFView.idleTimeout = null;
+    }
+
     // Pages have a higher priority than thumbnails, so check them first.
     var visiblePages = this.getVisiblePages();
     var pageView = this.getHighestPriority(visiblePages, this.pages,
@@ -1025,9 +1032,24 @@ var PDFView = {
       var thumbView = this.getHighestPriority(visibleThumbs,
                                               this.thumbnails,
                                               this.thumbnailViewScroll.down);
-      if (thumbView)
+      if (thumbView) {
         this.renderView(thumbView, 'thumbnail');
+        return;
+      }
     }
+
+    PDFView.idleTimeout = setTimeout(function () {
+      PDFView.cleanup();
+    }, CLEANUP_TIMEOUT);
+  },
+
+  cleanup: function pdfViewCleanup() {
+    for (var i = 0, ii = this.pages.length; i < ii; i++) {
+      if (this.pages[i]) {
+        this.pages[i].resetRenderingState();
+      }
+    }
+    this.pdfDocument.cleanup();
   },
 
   getHighestPriority: function pdfViewGetHighestPriority(visible, views,