1 files changed, 42 insertions, 0 deletions
diff --git a/www/external/packery.pkgd.js b/www/external/packery.pkgd.js
index c8353909..cd5b2a2c 100644
--- a/www/external/packery.pkgd.js
+++ b/www/external/packery.pkgd.js
@@ -2743,6 +2743,48 @@ Packery.Item = Item;
 
 var proto = Packery.prototype;
 
+// get JSON-friendly data for items positions
+Packery.prototype.getShiftPositions = function( attrName ) {
+  attrName = attrName || 'id';
+  var _this = this;
+  return this.items.map( function( item ) {
+    return {
+      attr: item.element.getAttribute( attrName ),
+      x: item.rect.x / _this.packer.width
+    }
+  });
+};
+
+Packery.prototype.initShiftLayout = function( positions, attr ) {
+  if ( !positions ) {
+    // if no initial positions, run packery layout
+    this.layout();
+    return;
+  }
+  // parse string to JSON
+  if ( typeof positions == 'string' ) {
+    try {
+      positions = JSON.parse( positions );
+    } catch( error ) {
+      console.error( 'JSON parse error: ' + error );
+      this.layout();
+      return;
+    }
+  }
+
+  attr = attr || 'id'; // default to id attribute
+  this._resetLayout();
+  // set item order and horizontal position from saved positions
+  this.items = positions.map( function( itemPosition ) {
+    var selector = '[' + attr + '="' + itemPosition.attr  + '"]'
+    var itemElem = this.element.querySelector( selector );
+    var item = this.getItem( itemElem );
+    item.rect.x = itemPosition.x * this.packer.width;
+    return item;
+  }, this );
+  this.shiftLayout();
+};
+
 proto._create = function() {
   // call super
   Outlayer.prototype._create.call( this );