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bower_components/iron-resizable-behavior/iron-resizable-behavior.html 6.26 KB
73bcce88   luigser   COMPONENTS
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  <!--

  @license

  Copyright (c) 2015 The Polymer Project Authors. All rights reserved.

  This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt

  The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt

  The complete set of contributors may be found at http://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 http://polymer.github.io/PATENTS.txt

  -->

  

  <link rel="import" href="../polymer/polymer.html">

  

  <script>

    /**

     * `IronResizableBehavior` is a behavior that can be used in Polymer elements to

     * coordinate the flow of resize events between "resizers" (elements that control the

     * size or hidden state of their children) and "resizables" (elements that need to be

     * notified when they are resized or un-hidden by their parents in order to take

     * action on their new measurements).

     * Elements that perform measurement should add the `IronResizableBehavior` behavior to

     * their element definition and listen for the `iron-resize` event on themselves.

     * This event will be fired when they become showing after having been hidden,

     * when they are resized explicitly by another resizable, or when the window has been

     * resized.

     * Note, the `iron-resize` event is non-bubbling.

     *

     * @polymerBehavior Polymer.IronResizableBehavior

     * @demo demo/index.html

     **/

    Polymer.IronResizableBehavior = {

      properties: {

        /**

         * The closest ancestor element that implements `IronResizableBehavior`.

         */

        _parentResizable: {

          type: Object,

          observer: '_parentResizableChanged'

        },

  

        /**

         * True if this element is currently notifying its descedant elements of

         * resize.

         */

        _notifyingDescendant: {

          type: Boolean,

          value: false

        }

      },

  

      listeners: {

        'iron-request-resize-notifications': '_onIronRequestResizeNotifications'

      },

  

      created: function() {

        // We don't really need property effects on these, and also we want them

        // to be created before the `_parentResizable` observer fires:

        this._interestedResizables = [];

        this._boundNotifyResize = this.notifyResize.bind(this);

      },

  

      attached: function() {

        this.fire('iron-request-resize-notifications', null, {

          node: this,

          bubbles: true,

          cancelable: true

        });

  

        if (!this._parentResizable) {

          window.addEventListener('resize', this._boundNotifyResize);

          this.notifyResize();

        }

      },

  

      detached: function() {

        if (this._parentResizable) {

          this._parentResizable.stopResizeNotificationsFor(this);

        } else {

          window.removeEventListener('resize', this._boundNotifyResize);

        }

  

        this._parentResizable = null;

      },

  

      /**

       * Can be called to manually notify a resizable and its descendant

       * resizables of a resize change.

       */

      notifyResize: function() {

        if (!this.isAttached) {

          return;

        }

  

        this._interestedResizables.forEach(function(resizable) {

          if (this.resizerShouldNotify(resizable)) {

            this._notifyDescendant(resizable);

          }

        }, this);

  

        this._fireResize();

      },

  

      /**

       * Used to assign the closest resizable ancestor to this resizable

       * if the ancestor detects a request for notifications.

       */

      assignParentResizable: function(parentResizable) {

        this._parentResizable = parentResizable;

      },

  

      /**

       * Used to remove a resizable descendant from the list of descendants

       * that should be notified of a resize change.

       */

      stopResizeNotificationsFor: function(target) {

        var index = this._interestedResizables.indexOf(target);

  

        if (index > -1) {

          this._interestedResizables.splice(index, 1);

          this.unlisten(target, 'iron-resize', '_onDescendantIronResize');

        }

      },

  

      /**

       * This method can be overridden to filter nested elements that should or

       * should not be notified by the current element. Return true if an element

       * should be notified, or false if it should not be notified.

       *

       * @param {HTMLElement} element A candidate descendant element that

       * implements `IronResizableBehavior`.

       * @return {boolean} True if the `element` should be notified of resize.

       */

      resizerShouldNotify: function(element) { return true; },

  

      _onDescendantIronResize: function(event) {

        if (this._notifyingDescendant) {

          event.stopPropagation();

          return;

        }

  

        // NOTE(cdata): In ShadowDOM, event retargetting makes echoing of the

        // otherwise non-bubbling event "just work." We do it manually here for

        // the case where Polymer is not using shadow roots for whatever reason:

        if (!Polymer.Settings.useShadow) {

          this._fireResize();

        }

      },

  

      _fireResize: function() {

        this.fire('iron-resize', null, {

          node: this,

          bubbles: false

        });

      },

  

      _onIronRequestResizeNotifications: function(event) {

        var target = event.path ? event.path[0] : event.target;

  

        if (target === this) {

          return;

        }

  

        if (this._interestedResizables.indexOf(target) === -1) {

          this._interestedResizables.push(target);

          this.listen(target, 'iron-resize', '_onDescendantIronResize');

        }

  

        target.assignParentResizable(this);

        this._notifyDescendant(target);

  

        event.stopPropagation();

      },

  

      _parentResizableChanged: function(parentResizable) {

        if (parentResizable) {

          window.removeEventListener('resize', this._boundNotifyResize);

        }

      },

  

      _notifyDescendant: function(descendant) {

        // NOTE(cdata): In IE10, attached is fired on children first, so it's

        // important not to notify them if the parent is not attached yet (or

        // else they will get redundantly notified when the parent attaches).

        if (!this.isAttached) {

          return;

        }

  

        this._notifyingDescendant = true;

        descendant.notifyResize();

        this._notifyingDescendant = false;

      }

    };

  </script>