paper-button.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
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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="../paper-behaviors/paper-button-behavior.html">
<link rel="import" href="../paper-material/paper-material-shared-styles.html">

<!--
Material design: [Buttons](https://www.google.com/design/spec/components/buttons.html)

`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>

To use `paper-button` as a link, wrap it in an anchor tag. Since `paper-button` will already
receive focus, you may want to prevent the anchor tag from receiving focus as well by setting
its tabindex to -1.

    <a href="https://www.polymer-project.org/" tabindex="-1">
      <paper-button raised>Polymer Project</paper-button>
    </a>

### 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 strip-whitespace>
    <style include="paper-material-shared-styles">
      :host {
        @apply(--layout-inline);
        @apply(--layout-center-center);
        position: relative;
        box-sizing: border-box;
        min-width: 5.14em;
        margin: 0 0.29em;
        background: transparent;
        -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
        -webkit-tap-highlight-color: transparent;
        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-font-common-base);
        @apply(--paper-button);
      }

      :host([hidden]) {
        display: none !important;
      }

      :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([animated]) {
        @apply(--shadow-transition);
      }

      paper-ripple {
        color: var(--paper-button-ink-color);
      }
    </style>

    <content></content>
  </template>

  <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._setElevation(0);
        } else {
          Polymer.PaperButtonBehaviorImpl._calculateElevation.apply(this);
        }
      }

      /**
      Fired when the animation finishes.
      This is useful if you want to wait until
      the ripple animation finishes to perform some action.

      @event transitionend
      Event param: {{node: Object}} detail Contains the animated node.
      */
    });
  </script>
</dom-module>