components/paper-fab/paper-fab.html

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@license
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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
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<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../iron-flex-layout/iron-flex-layout.html">
<link rel="import" href="../iron-icon/iron-icon.html">
<link rel="import" href="../paper-behaviors/paper-button-behavior.html">
<link rel="import" href="../paper-material/paper-material-shared-styles.html">
<link rel="import" href="../paper-styles/color.html">
<link rel="import" href="../paper-styles/default-theme.html">

<!--
Material design: [Floating Action Button](https://www.google.com/design/spec/components/buttons-floating-action-button.html)

`paper-fab` is a floating action button. It contains an image placed in the center and
comes in two sizes: regular size and a smaller size by applying the attribute `mini`. When
the user touches the button, a ripple effect emanates from the center of the button.

You may import `iron-icons` to use with this element, or provide a URL to a custom icon.
See `iron-iconset` for more information about how to use a custom icon set.

Example:

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

    <paper-fab icon="add"></paper-fab>
    <paper-fab mini icon="favorite"></paper-fab>
    <paper-fab src="star.png"></paper-fab>


### Styling

The following custom properties and mixins are available for styling:

Custom property | Description | Default
----------------|-------------|----------
`--paper-fab-background` | The background color of the button | `--accent-color`
`--paper-fab-keyboard-focus-background` | The background color of the button when focused | `--paper-pink-900`
`--paper-fab-disabled-background` | The background color of the button when it's disabled | `--paper-grey-300`
`--paper-fab-disabled-text` | The text color of the button when it's disabled | `--paper-grey-500`
`--paper-fab` | Mixin applied to the button | `{}`
`--paper-fab-mini` | Mixin applied to a mini button | `{}`
`--paper-fab-disabled` | Mixin applied to a disabled button | `{}`
`--paper-fab-iron-icon` | Mixin applied to the iron-icon within the button | `{}`
`--paper-fab-label` | Mixin applied to the label within the button | `{}`

@group Paper Elements
@demo demo/index.html
-->

<dom-module id="paper-fab">
  <template strip-whitespace>
    <style include="paper-material-shared-styles">
      :host {
        @apply(--layout-vertical);
        @apply(--layout-center-center);

        background: var(--paper-fab-background, --accent-color);
        border-radius: 50%;
        box-sizing: border-box;
        color: var(--text-primary-color);
        cursor: pointer;
        height: 56px;
        min-width: 0;
        outline: none;
        padding: 16px;
        position: relative;
        -moz-user-select: none;
        -ms-user-select: none;
        -webkit-user-select: none;
        user-select: none;
        width: 56px;
        z-index: 0;

        /* NOTE: Both values are needed, since some phones require the value `transparent`. */
        -webkit-tap-highlight-color: rgba(0,0,0,0);
        -webkit-tap-highlight-color: transparent;

        @apply(--paper-fab);
      }

      [hidden] {
        display: none !important;
      }

      :host([mini]) {
        width: 40px;
        height: 40px;
        padding: 8px;

        @apply(--paper-fab-mini);
      }

      :host([disabled]) {
        color: var(--paper-fab-disabled-text, --paper-grey-500);
        background: var(--paper-fab-disabled-background, --paper-grey-300);

        @apply(--paper-fab-disabled);
      }

      iron-icon {
        @apply(--paper-fab-iron-icon);
      }

      span {
        width: 100%;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
        text-align: center;

        @apply(--paper-fab-label);
      }

      :host(.keyboard-focus) {
        background: var(--paper-fab-keyboard-focus-background, --paper-pink-900);
      }
    </style>

    <iron-icon id="icon" hidden$="{{!_computeIsIconFab(icon, src)}}" src="[[src]]" icon="[[icon]]"></iron-icon>
    <span hidden$="{{_computeIsIconFab(icon, src)}}">{{label}}</span>
  </template>

  <script>
    Polymer({
      is: 'paper-fab',

      behaviors: [
        Polymer.PaperButtonBehavior
      ],

      properties: {
        /**
         * The URL of an image for the icon. If the src property is specified,
         * the icon property should not be.
         */
        src: {
          type: String,
          value: ''
        },

        /**
         * Specifies the icon name or index in the set of icons available in
         * the icon's icon set. If the icon property is specified,
         * the src property should not be.
         */
        icon: {
          type: String,
          value: ''
        },

        /**
         * Set this to true to style this is a "mini" FAB.
         */
        mini: {
          type: Boolean,
          value: false,
          reflectToAttribute: true
        },

        /**
         * The label displayed in the badge. The label is centered, and ideally
         * should have very few characters.
         */
        label: {
          type: String,
          observer: '_labelChanged'
        }
      },

      _labelChanged: function() {
        this.setAttribute('aria-label', this.label);
      },

      _computeIsIconFab: function(icon, src) {
        return (icon.length > 0) || (src.length > 0);
      }
    });
  </script>
</dom-module>