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">

<!--

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.

    /* make #my-button green with yellow text */
    #my-button {
        background: green;
        color: yellow;
    }

By default, the ripple is the same color as the foreground at 25% opacity. You may
customize the color using this selector:

    /* make #my-button use a blue ripple instead of foreground color */
    #my-button::shadow paper-ripple {
      color: blue;
    }

The opacity of the ripple is not customizable via CSS.

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

Custom property | Description | Default
----------------|-------------|----------
`--paper-button-flat-focus-color` | Background color of a focused flat button | `--paper-grey-200`
`--paper-button` | Mixin applied to the button | `{}`
`--paper-button-disabled` | Mixin applied to the disabled button | `{}`

@demo demo/index.html
-->

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

  <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: none;
      border-radius: 3px;
      -moz-user-select: none;
      -ms-user-select: none;
      -webkit-user-select: none;
      user-select: none;
      cursor: pointer;
      z-index: 0;

      @apply(--paper-button);
    }

    .keyboard-focus {
      font-weight: bold;
    }

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

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

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

    paper-material {
      border-radius: inherit;
    }

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

    .content {
      padding: 0.7em 0.57em
    }
  </style>

  <template>

    <paper-ripple></paper-ripple>

    <paper-material class$="[[_computeContentClass(receivedFocusFromKeyboard)]]" elevation="[[_elevation]]" animated>
      <content></content>
    </paper-material>

  </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>