components/iron-icon/iron-icon.html

<!--
@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">
<link rel="import" href="../iron-meta/iron-meta.html">
<link rel="import" href="../iron-flex-layout/iron-flex-layout.html">

<!--

The `iron-icon` element displays an icon. By default an icon renders as a 24px square.

Example using src:

    <iron-icon src="star.png"></iron-icon>

Example setting size to 32px x 32px:

    <iron-icon class="big" src="big_star.png"></iron-icon>

    <style is="custom-style">
      .big {
        --iron-icon-height: 32px;
        --iron-icon-width: 32px;
      }
    </style>

The iron elements include several sets of icons.
To use the default set of icons, import `iron-icons.html` and use the `icon` attribute to specify an icon:

    <link rel="import" href="/components/iron-icons/iron-icons.html">

    <iron-icon icon="menu"></iron-icon>

To use a different built-in set of icons, import the specific `iron-icons/<iconset>-icons.html`, and
specify the icon as `<iconset>:<icon>`. For example, to use a communication icon, you would
use:

    <link rel="import" href="/components/iron-icons/communication-icons.html">

    <iron-icon icon="communication:email"></iron-icon>

You can also create custom icon sets of bitmap or SVG icons.

Example of using an icon named `cherry` from a custom iconset with the ID `fruit`:

    <iron-icon icon="fruit:cherry"></iron-icon>

See [iron-iconset](iron-iconset) and [iron-iconset-svg](iron-iconset-svg) for more information about
how to create a custom iconset.

See the [iron-icons demo](iron-icons?view=demo:demo/index.html) to see the icons available
in the various iconsets.

To load a subset of icons from one of the default `iron-icons` sets, you can
use the [poly-icon](https://poly-icon.appspot.com/) tool. It allows you
to select individual icons, and creates an iconset from them that you can
use directly in your elements.

### Styling

The following custom properties are available for styling:

Custom property | Description | Default
----------------|-------------|----------
`--iron-icon-width` | Width of the icon | `24px`
`--iron-icon-height` | Height of the icon | `24px`
`--iron-icon-fill-color` | Fill color of the svg icon | `currentcolor`
`--iron-icon-stroke-color` | Stroke color of the svg icon | none

@group Iron Elements
@element iron-icon
@demo demo/index.html
@hero hero.svg
@homepage polymer.github.io
-->

<dom-module id="iron-icon">

  <style>
    :host {
      @apply(--layout-inline);
      @apply(--layout-center-center);
      position: relative;

      vertical-align: middle;

      fill: var(--iron-icon-fill-color, currentcolor);
      stroke: var(--iron-icon-stroke-color, none);

      width: var(--iron-icon-width, 24px);
      height: var(--iron-icon-height, 24px);
    }
  </style>

  <template>
  </template>

  <script>

    Polymer({

      is: 'iron-icon',

      properties: {

        /**
         * The name of the icon to use. The name should be of the form:
         * `iconset_name:icon_name`.
         */
        icon: {
          type: String,
          observer: '_iconChanged'
        },

        /**
         * The name of the theme to used, if one is specified by the
         * iconset.
         */
        theme: {
          type: String,
          observer: '_updateIcon'
        },

        /**
         * If using iron-icon without an iconset, you can set the src to be
         * the URL of an individual icon image file. Note that this will take
         * precedence over a given icon attribute.
         */
        src: {
          type: String,
          observer: '_srcChanged'
        },

        /**
         * @type {!Polymer.IronMeta}
         */
        _meta: {
          value: Polymer.Base.create('iron-meta', {type: 'iconset'}),
          observer: '_updateIcon'
        }

      },

      _DEFAULT_ICONSET: 'icons',

      _iconChanged: function(icon) {
        var parts = (icon || '').split(':');
        this._iconName = parts.pop();
        this._iconsetName = parts.pop() || this._DEFAULT_ICONSET;
        this._updateIcon();
      },

      _srcChanged: function(src) {
        this._updateIcon();
      },

      _usesIconset: function() {
        return this.icon || !this.src;
      },

      /** @suppress {visibility} */
      _updateIcon: function() {
        if (this._usesIconset()) {
          if (this._img && this._img.parentNode) {
            Polymer.dom(this.root).removeChild(this._img);
          }
          if (this._iconName === "") {
            if (this._iconset) {
              this._iconset.removeIcon(this);
            }
          } else if (this._iconsetName && this._meta) {
            this._iconset = /** @type {?Polymer.Iconset} */ (
              this._meta.byKey(this._iconsetName));
            if (this._iconset) {
              this._iconset.applyIcon(this, this._iconName, this.theme);
              this.unlisten(window, 'iron-iconset-added', '_updateIcon');
            } else {
              this.listen(window, 'iron-iconset-added', '_updateIcon');
            }
          }
        } else {
          if (this._iconset) {
            this._iconset.removeIcon(this);
          }
          if (!this._img) {
            this._img = document.createElement('img');
            this._img.style.width = '100%';
            this._img.style.height = '100%';
            this._img.draggable = false;
          }
          this._img.src = this.src;
          Polymer.dom(this.root).appendChild(this._img);
        }
      }

    });

  </script>

</dom-module>