third_party/polymer/components/core-media-query/core-media-query.html

   1 <!--
   2 Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
   3 This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
   4 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
   5 The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
   6 Code distributed by Google as part of the polymer project is also
   7 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
   8 -->
   9 <!--
  10 /**
  11  * @group Polymer Core Elements
  12  * @element core-media-query
  13  * @status beta
  14  * @homepage github.io
  15  *
  16  * core-media-query can be used to data bind to a CSS media query.
  17  * The "query" property is a bare CSS media query.
  18  * The "queryMatches" property will be a boolean representing if the page matches that media query.
  19  *
  20  * core-media-query uses media query listeners to dynamically update the "queryMatches" property.
  21  * A "core-media-change" event also fires when queryMatches changes.
  22  *
  23  * Example:
  24  *
  25  *      <core-media-query query="max-width: 640px" queryMatches="{{phoneScreen}}"></core-media-query>
  26  *
  27  */
  28
  29  /**
  30   * Fired when the media query state changes
  31   *
  32   * @event core-media-change
  33   */
  34 -->
  35 <link rel="import" href="../polymer/polymer.html">
  36
  37 <polymer-element name="core-media-query" attributes="query queryMatches">
  38   <template>
  39     <style>
  40       :host {
  41         display: none;
  42       }
  43     </style>
  44   </template>
  45   <script>
  46     Polymer('core-media-query', {
  47
  48       /**
  49        * The Boolean return value of the media query
  50        *
  51        * @attribute queryMatches
  52        * @type Boolean
  53        * @default false
  54        */
  55       queryMatches: false,
  56
  57       /**
  58        * The CSS media query to evaulate
  59        *
  60        * @attribute query
  61        * @type string
  62        * @default ''
  63        */
  64       query: '',
  65       ready: function() {
  66         this._mqHandler = this.queryHandler.bind(this);
  67         this._mq = null;
  68       },
  69       queryChanged: function() {
  70         if (this._mq) {
  71           this._mq.removeListener(this._mqHandler);
  72         }
  73         var query = this.query;
  74         if (query[0] !== '(') {
  75           query = '(' + this.query + ')';
  76         }
  77         this._mq = window.matchMedia(query);
  78         this._mq.addListener(this._mqHandler);
  79         this.queryHandler(this._mq);
  80       },
  81       queryHandler: function(mq) {
  82         this.queryMatches = mq.matches;
  83         this.asyncFire('core-media-change', mq);
  84       }
  85     });
  86   </script>
  87 </polymer-element>