WebCompDev / COMPONENTS

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<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../paper-material/paper-material.html">
<link rel="import" href="../paper-ripple/paper-ripple.html">
<link rel="import" href="../paper-behaviors/paper-button-behavior.html">
<link rel="import" href="../iron-flex-layout/iron-flex-layout.html">

<!--

Material Design: <a href="http://www.google.com/design/spec/components/buttons.html">Buttons</a>

`paper-button` is a button. When the user touches the button, a ripple effect emanates
from the point of contact. It may be flat or raised. A raised button is styled with a
shadow.

Example:

    <paper-button>Flat button</paper-button>
    <paper-button raised>Raised button</paper-button>
    <paper-button noink>No ripple effect</paper-button>
    <paper-button toggles>Toggle-able button</paper-button>

A button that has `toggles` true will remain `active` after being clicked (and
will have an `active` attribute set). For more information, see the `Polymer.IronButtonState`
behavior.

You may use custom DOM in the button body to create a variety of buttons. For example, to
create a button with an icon and some text:

    <paper-button>
      <iron-icon icon="favorite"></iron-icon>
      custom button content
    </paper-button>

### Styling

Style the button with CSS as you would a normal DOM element.

    paper-button.fancy {
      background: green;
      color: yellow;
    }

    paper-button.fancy:hover {
      background: lime;
    }

    paper-button[disabled],
    paper-button[toggles][active] {
      background: red;
    }

By default, the ripple is the same color as the foreground at 25% opacity. You may
customize the color using the `--paper-button-ink-color` custom property.

The following custom properties and mixins are also available for styling:

Custom property | Description | Default
----------------|-------------|----------
`--paper-button-ink-color` | Background color of the ripple | `Based on the button's color`
`--paper-button` | Mixin applied to the button | `{}`
`--paper-button-disabled` | Mixin applied to the disabled button. Note that you can also use the `paper-button[disabled]` selector | `{}`
`--paper-button-flat-keyboard-focus` | Mixin applied to a flat button after it's been focused using the keyboard | `{}`
`--paper-button-raised-keyboard-focus` | Mixin applied to a raised button after it's been focused using the keyboard | `{}`

@demo demo/index.html
-->

<dom-module id="paper-button">
  <template>

    <style>
      :host {
        display: inline-block;
        position: relative;
        box-sizing: border-box;
        min-width: 5.14em;
        margin: 0 0.29em;
        background: transparent;
        text-align: center;
        font: inherit;
        text-transform: uppercase;
        outline-width: 0;
        border-radius: 3px;
        -moz-user-select: none;
        -ms-user-select: none;
        -webkit-user-select: none;
        user-select: none;
        cursor: pointer;
        z-index: 0;
        padding: 0.7em 0.57em;

        @apply(--paper-button);
      }

      :host([raised]) .keyboard-focus {
        font-weight: bold;
        @apply(--paper-button-raised-keyboard-focus);
      }

      :host(:not([raised])) .keyboard-focus {
        font-weight: bold;
        @apply(--paper-button-flat-keyboard-focus);
      }

      :host([disabled]) {
        background: #eaeaea;
        color: #a8a8a8;
        cursor: auto;
        pointer-events: none;

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

      :host([noink]) paper-ripple {
        display: none;
      }

      paper-ripple {
        color: var(--paper-button-ink-color);
      }

      paper-material {
        border-radius: inherit;
        @apply(--layout-fit);
      }

      .content > ::content * {
        text-transform: inherit;
      }
    </style>

    <paper-ripple></paper-ripple>

    <paper-material  elevation="[[_elevation]]" animated></paper-material>

    <div class$="[[_computeContentClass(receivedFocusFromKeyboard)]]">
      <content></content>
    </div>

  </template>
</dom-module>

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

    behaviors: [
      Polymer.PaperButtonBehavior
    ],

    properties: {
      /**
       * If true, the button should be styled with a shadow.
       */
      raised: {
        type: Boolean,
        reflectToAttribute: true,
        value: false,
        observer: '_calculateElevation'
      }
    },

    _calculateElevation: function() {
      if (!this.raised) {
        this._elevation = 0;
      } else {
        Polymer.PaperButtonBehaviorImpl._calculateElevation.apply(this);
      }
    },

    _computeContentClass: function(receivedFocusFromKeyboard) {
      var className = 'content ';
      if (receivedFocusFromKeyboard) {
        className += ' keyboard-focus';
      }
      return className;
    }
  });
</script>