<!– @license Copyright © 2015 The Polymer Project Authors. All rights reserved. This code may only be used under the BSD style license found at polymer.github.io/LICENSE.txt The complete set of authors may be found at polymer.github.io/AUTHORS.txt The complete set of contributors may be found at 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 polymer.github.io/PATENTS.txt –>

<link rel=“import” href=“../polymer/polymer.html”> <link rel=“import” href=“../iron-flex-layout/iron-flex-layout.html”> <link rel=“import” href=“../iron-image/iron-image.html”> <link rel=“import” href=“../paper-material/paper-material.html”> <link rel=“import” href=“../paper-styles/default-theme.html”>

<!– Material design: [Cards](www.google.com/design/spec/components/cards.html)

`paper-card` is a container with a drop shadow.

Example:

<paper-card heading="Card Title">
  <div class="card-content">Some content</div>
  <div class="card-actions">
    <paper-button>Some action</paper-button>
  </div>
</paper-card>

Example - top card image:

<paper-card heading="Card Title" image="/path/to/image.png" alt="image">
  ...
</paper-card>

### Accessibility

By default, the `aria-label` will be set to the value of the `heading` attribute.

### Styling

The following custom properties and mixins are available for styling:

Custom property | Description | Default —————-|————-|———- `–paper-card-background-color` | The background color of the card | `–primary-background-color` `–paper-card-header-color` | The color of the header text | `#000` `–paper-card-header` | Mixin applied to the card header section | `{}` `–paper-card-header-text` | Mixin applied to the title in the card header section | `{}` `–paper-card-header-image` | Mixin applied to the image in the card header section | `{}` `–paper-card-header-image-text` | Mixin applied to the text overlapping the image in the card header section | `{}` `–paper-card-content` | Mixin applied to the card content section| `{}` `–paper-card-actions` | Mixin applied to the card action section | `{}` `–paper-card` | Mixin applied to the card | `{}`

@group Paper Elements @element paper-card @demo demo/index.html –>

<dom-module id=“paper-card”>

<template>
  <style include="paper-material">
    :host {
      display: inline-block;
      position: relative;
      box-sizing: border-box;
      background-color: var(--paper-card-background-color, --primary-background-color);
      border-radius: 2px;

      @apply(--paper-font-common-base);
      @apply(--paper-card);
    }

    /* IE 10 support for HTML5 hidden attr */
    [hidden] {
      display: none !important;
    }

    .header {
      position: relative;
      border-top-left-radius: inherit;
      border-top-right-radius: inherit;
      overflow: hidden;

      @apply(--paper-card-header);
    }

    .header iron-image {
      display: block;
      width: 100%;
      --iron-image-width: 100%;
      pointer-events: none;

      @apply(--paper-card-header-image);
    }

    .header .title-text {
      padding: 16px;
      font-size: 24px;
      font-weight: 400;
      color: var(--paper-card-header-color, #000);

      @apply(--paper-card-header-text);
    }

    .header .title-text.over-image {
      position: absolute;
      bottom: 0px;

      @apply(--paper-card-header-image-text);
    }

    :host ::content .card-content {
      padding: 16px;
      position:relative;

      @apply(--paper-card-content);
    }

    :host ::content .card-actions {
      border-top: 1px solid #e8e8e8;
      padding: 5px 16px;
      position:relative;

      @apply(--paper-card-actions);
    }
  </style>

  <div class="header">
    <iron-image
        hidden$="[[!image]]"
        aria-hidden$="[[_isHidden(image)]]"
        src="[[image]]"
        alt="[[alt]]"
        placeholder="[[placeholderImage]]"
        preload="[[preloadImage]]"
        fade="[[fadeImage]]"></iron-image>
    <div hidden$="[[!heading]]" class$="title-text [[_computeHeadingClass(image)]]">[[heading]]</div>
  </div>

  <content></content>
</template>

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

    properties: {
      /**
       * The title of the card.
       */
      heading: {
        type: String,
        value: '',
        observer: '_headingChanged'
      },

      /**
       * The url of the title image of the card.
       */
      image: {
        type: String,
        value: ''
      },

      /**
       * The text alternative of the card's title image.
       */
      alt: {
        type: String
      },

      /**
       * When `true`, any change to the image url property will cause the
       * `placeholder` image to be shown until the image is fully rendered.
       */
      preloadImage: {
        type: Boolean,
        value: false
      },

      /**
       * When `preloadImage` is true, setting `fadeImage` to true will cause the
       * image to fade into place.
       */
      fadeImage: {
        type: Boolean,
        value: false
      },

      /**
       * This image will be used as a background/placeholder until the src image has
       * loaded. Use of a data-URI for placeholder is encouraged for instant rendering.
       */
      placeholderImage: {
        type: String,
        value: null
      },

      /**
       * The z-depth of the card, from 0-5.
       */
      elevation: {
        type: Number,
        value: 1,
        reflectToAttribute: true
      },

      /**
       * Set this to true to animate the card shadow when setting a new
       * `z` value.
       */
      animatedShadow: {
        type: Boolean,
        value: false
      },

      /**
       * Read-only property used to pass down the `animatedShadow` value to
       * the underlying paper-material style (since they have different names).
       */
      animated: {
        type: Boolean,
        reflectToAttribute: true,
        readOnly: true,
        computed: '_computeAnimated(animatedShadow)'
      }
    },

    /**
     * Format function for aria-hidden. Use the ! operator results in the
     * empty string when given a falsy value.
     */
    _isHidden: function(image) {
      return image ? 'false' : 'true';
    },

    _headingChanged: function(heading) {
      var label = this.getAttribute('aria-label');
      this.setAttribute('aria-label', heading);
    },

    _computeHeadingClass: function(image) {
      return image ? ' over-image' : '';
    },

    _computeAnimated: function(animatedShadow) {
      return animatedShadow;
    }
  });
</script>

</dom-module>