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` | Mixin applied to the icon | {}
`--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">
  <template>
    <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);
        @apply(--iron-icon);
      }
    </style>
  </template>
</dom-module>
<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
    },

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

    /**
      * 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
    },

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

  },

  observers: [
    '_updateIcon(_meta, isAttached)',
    '_updateIcon(theme, isAttached)',
    '_srcChanged(src, isAttached)',
    '_iconChanged(icon, isAttached)'
  ],

  _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>