paper-button.html

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<!--
@group Paper Elements

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>

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>
      <core-icon icon="favorite"></core-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 #ripple {
      color: blue;
    }

The opacity of the ripple is not customizable via CSS.

@element paper-button
@extends paper-button-base
@status unstable
-->

<link href="../polymer/polymer.html" rel="import">
<link href="../paper-shadow/paper-shadow.html" rel="import">
<link href="../core-a11y-keys/core-a11y-keys.html" rel="import">

<link href="paper-button-base.html" rel="import">

<polymer-element name="paper-button" extends="paper-button-base" attributes="raised recenteringTouch fill"
role="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: none;
        border-radius: 3px;
        -moz-user-select: none;
        -ms-user-select: none;
        -webkit-user-select: none;
        user-select: none;
        cursor: pointer;
        z-index: 0;
      }

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

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

      #bg, #shadow {
        border-radius: inherit;
      }

      #ripple {
        pointer-events: none;
        z-index: -1;
      }

      .button-content {
        padding: 0.7em 0.57em
      }

      polyfill-next-selector { content: '.button-content > a'; }
      ::content > a {
        height: 100%;
        padding: 0.7em 0.57em;
        margin: -0.7em -0.57em;
        /* flex */
        -ms-flex: 1 1 0.000000001px;
        -webkit-flex: 1;
        flex: 1;
        -webkit-flex-basis: 0.000000001px;
        flex-basis: 0.000000001px;
      }

    </style>

    <template if="{{raised}}">
      <paper-shadow id="shadow" fit animated></paper-shadow>
    </template>

    <!-- this div is needed to position the ripple behind text content -->
    <div class="button-content" relative layout horizontal center-center>
      <content></content>
    </div>

    <core-a11y-keys keys="space enter" target="{{}}" on-keys-pressed="{{_activate}}"></core-a11y-keys>

  </template>

  <script>
    Polymer({

      publish: {

        /**
         * If true, the button will be styled with a shadow.
         *
         * @attribute raised
         * @type boolean
         * @default false
         */
        raised: false,

        /**
         * By default the ripple emanates from where the user touched the button.
         * Set this to true to always center the ripple.
         *
         * @attribute recenteringTouch
         * @type boolean
         * @default false
         */
        recenteringTouch: false,

        /**
         * By default the ripple expands to fill the button. Set this to true to
         * constrain the ripple to a circle within the button.
         *
         * @attribute fill
         * @type boolean
         * @default true
         */
        fill: true

      },

      _activate: function() {
        this.click();
        this.fire('tap');
        if (!this.pressed) {
          var bcr = this.getBoundingClientRect();
          var x = bcr.left + (bcr.width / 2);
          var y = bcr.top + (bcr.height / 2);
          this.downAction({x: x, y: y});
          var fn = function fn() {
            this.upAction();
            this.removeEventListener('keyup', fn);
          }.bind(this);
          this.addEventListener('keyup', fn);
        }
      }

    });
  </script>
</polymer-element>