<!– @license Copyright © 2015 The Polymer Project Authors. All rights reserved. This code may only be used under the BSD style license found at polymer.github.io/LICENSE.txt The complete set of authors may be found at polymer.github.io/AUTHORS.txt The complete set of contributors may be found at polymer.github.io/CONTRIBUTORS.txt Code distributed by Google as part of the polymer project is also subject to an additional IP rights grant found at polymer.github.io/PATENTS.txt –>

<link rel=“import” href=“../polymer/polymer.html”> <link rel=“import” href=“neon-animation-behavior.html”>

<script>

/**
 * Use `Polymer.NeonSharedElementAnimationBehavior` to implement shared element animations.
 * @polymerBehavior Polymer.NeonSharedElementAnimationBehavior
 */
Polymer.NeonSharedElementAnimationBehaviorImpl = {

  properties: {

    /**
     * Cached copy of shared elements.
     */
    sharedElements: {
      type: Object
    }

  },

  /**
   * Finds shared elements based on `config`.
   */
  findSharedElements: function(config) {
    var fromPage = config.fromPage;
    var toPage = config.toPage;
    if (!fromPage || !toPage) {
      console.warn(this.is + ':', !fromPage ? 'fromPage' : 'toPage', 'is undefined!');
      return null;
    };

    if (!fromPage.sharedElements || !toPage.sharedElements) {
      console.warn(this.is + ':', 'sharedElements are undefined for', !fromPage.sharedElements ? fromPage : toPage);
      return null;
    };

    var from = fromPage.sharedElements[config.id]
    var to = toPage.sharedElements[config.id];

    if (!from || !to) {
      console.warn(this.is + ':', 'sharedElement with id', config.id, 'not found in', !from ? fromPage : toPage);
      return null;
    }

    this.sharedElements = {
      from: from,
      to: to
    };
    return this.sharedElements;
  }

};

/** @polymerBehavior Polymer.NeonSharedElementAnimationBehavior */
Polymer.NeonSharedElementAnimationBehavior = [
  Polymer.NeonAnimationBehavior,
  Polymer.NeonSharedElementAnimationBehaviorImpl
];

</script>