paper-checkbox.html

<!--
@license
Copyright (c) 2016 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
subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
-->

<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../paper-styles/default-theme.html">
<link rel="import" href="../paper-behaviors/paper-checked-element-behavior.html">

<!--
Material design: [Checkbox](https://www.google.com/design/spec/components/selection-controls.html#selection-controls-checkbox)

`paper-checkbox` is a button that can be either checked or unchecked.  User
can tap the checkbox to check or uncheck it.  Usually you use checkboxes
to allow user to select multiple options from a set.  If you have a single
ON/OFF option, avoid using a single checkbox and use `paper-toggle-button`
instead.

Example:

    <paper-checkbox>label</paper-checkbox>

    <paper-checkbox checked> label</paper-checkbox>

### Styling

The following custom properties and mixins are available for styling:

Custom property | Description | Default
----------------|-------------|----------
`--paper-checkbox-unchecked-background-color` | Checkbox background color when the input is not checked | `transparent`
`--paper-checkbox-unchecked-color` | Checkbox border color when the input is not checked | `--primary-text-color`
`--paper-checkbox-unchecked-ink-color` | Selected/focus ripple color when the input is not checked | `--primary-text-color`
`--paper-checkbox-checked-color` | Checkbox color when the input is checked | `--primary-color`
`--paper-checkbox-checked-ink-color` | Selected/focus ripple color when the input is checked | `--primary-color`
`--paper-checkbox-checkmark-color` | Checkmark color | `white`
`--paper-checkbox-label-color` | Label color | `--primary-text-color`
`--paper-checkbox-label-checked-color` | Label color when the input is checked | `--paper-checkbox-label-color`
`--paper-checkbox-label-spacing` | Spacing between the label and the checkbox | `8px`
`--paper-checkbox-error-color` | Checkbox color when invalid | `--error-color`
`--paper-checkbox-size` | Size of the checkbox | `18px`
`--paper-checkbox-margin` | Margin around the checkbox container | `initial`
`--paper-checkbox-vertical-align` | Vertical alignment of the checkbox container | `middle`

This element applies the mixin `--paper-font-common-base` but does not import `paper-styles/typography.html`.
In order to apply the `Roboto` font to this element, make sure you've imported `paper-styles/typography.html`.

@demo demo/index.html
-->

<dom-module id="paper-checkbox">
  <template strip-whitespace>
    <style>
      :host {
        display: inline-block;
        white-space: nowrap;
        cursor: pointer;
        --calculated-paper-checkbox-size: var(--paper-checkbox-size, 18px);
        @apply(--paper-font-common-base);
        line-height: 0;
        -webkit-tap-highlight-color: transparent;
      }

      :host(:focus) {
        outline: none;
      }

      .hidden {
        display: none;
      }

      #checkboxContainer {
        display: inline-block;
        position: relative;
        width: var(--calculated-paper-checkbox-size);
        height: var(--calculated-paper-checkbox-size);
        min-width: var(--calculated-paper-checkbox-size);
        margin: var(--paper-checkbox-margin, initial);
        vertical-align: var(--paper-checkbox-vertical-align, middle);
        background-color: var(--paper-checkbox-unchecked-background-color, transparent);
      }

      #ink {
        position: absolute;

        /* Center the ripple in the checkbox by negative offsetting it by
         * (inkWidth - rippleWidth) / 2 */
        top: calc(0px - (2.66 * var(--calculated-paper-checkbox-size) - var(--calculated-paper-checkbox-size)) / 2);
        left: calc(0px - (2.66 * var(--calculated-paper-checkbox-size) - var(--calculated-paper-checkbox-size)) / 2);
        width: calc(2.66 * var(--calculated-paper-checkbox-size));
        height: calc(2.66 * var(--calculated-paper-checkbox-size));
        color: var(--paper-checkbox-unchecked-ink-color, --primary-text-color);
        opacity: 0.6;
        pointer-events: none;
      }

      :host-context([dir="rtl"]) #ink {
        right: calc(0px - (2.66 * var(--calculated-paper-checkbox-size) - var(--calculated-paper-checkbox-size)) / 2);
        left: auto;
      }

      #ink[checked] {
        color: var(--paper-checkbox-checked-ink-color, --primary-color);
      }

      #checkbox {
        position: relative;
        box-sizing: border-box;
        height: 100%;
        border: solid 2px;
        border-color: var(--paper-checkbox-unchecked-color, --primary-text-color);
        border-radius: 2px;
        pointer-events: none;
        -webkit-transition: background-color 140ms, border-color 140ms;
        transition: background-color 140ms, border-color 140ms;
      }

      /* checkbox checked animations */
      #checkbox.checked #checkmark {
        -webkit-animation: checkmark-expand 140ms ease-out forwards;
        animation: checkmark-expand 140ms ease-out forwards;
      }

      @-webkit-keyframes checkmark-expand {
        0% {
          -webkit-transform: scale(0, 0) rotate(45deg);
        }
        100% {
          -webkit-transform: scale(1, 1) rotate(45deg);
        }
      }

      @keyframes checkmark-expand {
        0% {
          transform: scale(0, 0) rotate(45deg);
        }
        100% {
          transform: scale(1, 1) rotate(45deg);
        }
      }

      #checkbox.checked {
        background-color: var(--paper-checkbox-checked-color, --primary-color);
        border-color: var(--paper-checkbox-checked-color, --primary-color);
      }

      #checkmark {
        position: absolute;
        width: 36%;
        height: 70%;
        border-style: solid;
        border-top: none;
        border-left: none;
        border-right-width: calc(2/15 * var(--calculated-paper-checkbox-size));
        border-bottom-width: calc(2/15 * var(--calculated-paper-checkbox-size));
        border-color: var(--paper-checkbox-checkmark-color, white);
        -webkit-transform-origin: 97% 86%;
        transform-origin: 97% 86%;
        box-sizing: content-box; /* protect against page-level box-sizing */
      }

      :host-context([dir="rtl"]) #checkmark {
        -webkit-transform-origin: 50% 14%;
        transform-origin: 50% 14%;
      }

      /* label */
      #checkboxLabel {
        position: relative;
        display: inline-block;
        vertical-align: middle;
        padding-left: var(--paper-checkbox-label-spacing, 8px);
        white-space: normal;
        line-height: normal;
        color: var(--paper-checkbox-label-color, --primary-text-color);
      }

      :host([checked]) #checkboxLabel {
        color: var(--paper-checkbox-label-checked-color, --paper-checkbox-label-color);
      }

      :host-context([dir="rtl"]) #checkboxLabel {
        padding-right: var(--paper-checkbox-label-spacing, 8px);
        padding-left: 0;
      }

      #checkboxLabel[hidden] {
        display: none;
      }

      /* disabled state */

      :host([disabled]) #checkbox {
        opacity: 0.5;
        border-color: var(--paper-checkbox-unchecked-color, --primary-text-color);
      }

      :host([disabled][checked]) #checkbox {
        background-color: var(--paper-checkbox-unchecked-color, --primary-text-color);
        opacity: 0.5;
      }

      :host([disabled]) #checkboxLabel  {
        opacity: 0.65;
      }

      /* invalid state */
      #checkbox.invalid:not(.checked) {
        border-color: var(--paper-checkbox-error-color, --error-color);
      }
    </style>

    <div id="checkboxContainer">
      <div id="checkbox" class$="[[_computeCheckboxClass(checked, invalid)]]">
        <div id="checkmark" class$="[[_computeCheckmarkClass(checked)]]"></div>
      </div>
    </div>

    <div id="checkboxLabel"><content></content></div>
  </template>

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

      behaviors: [
        Polymer.PaperCheckedElementBehavior
      ],

      hostAttributes: {
        role: 'checkbox',
        'aria-checked': false,
        tabindex: 0
      },

      properties: {
        /**
         * Fired when the checked state changes due to user interaction.
         *
         * @event change
         */

        /**
         * Fired when the checked state changes.
         *
         * @event iron-change
         */
        ariaActiveAttribute: {
          type: String,
          value: 'aria-checked'
        }
      },

      _computeCheckboxClass: function(checked, invalid) {
        var className = '';
        if (checked) {
          className += 'checked ';
        }
        if (invalid) {
          className += 'invalid';
        }
        return className;
      },

      _computeCheckmarkClass: function(checked) {
        return checked ? '' : 'hidden';
      },

      // create ripple inside the checkboxContainer
      _createRipple: function() {
        this._rippleContainer = this.$.checkboxContainer;
        return Polymer.PaperInkyFocusBehaviorImpl._createRipple.call(this);
      }

    });
  </script>
</dom-module>