Upgrade to 1.0 and switch clients to dom-repeat where needed.

third_party/polymer/v0_8/components/iron-image/iron-image.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
+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="../iron-flex-layout/classes/iron-flex-layout.html">
+
+<!--
+`iron-image` is an element for displaying an image that provides useful sizing and
+preloading options not found on the standard `<img>` tag.
+
+The `sizing` option allows the image to be either cropped (`cover`) or
+letterboxed (`contain`) to fill a fixed user-size placed on the element.
+
+The `preload` option prevents the browser from rendering the image until the
+image is fully loaded.  In the interim, either the element's CSS `background-color`
+can be be used as the placeholder, or the `placeholder` property can be
+set to a URL (preferably a data-URI, for instant rendering) for an
+placeholder image.
+
+The `fade` option (only valid when `preload` is set) will cause the placeholder
+image/color to be faded out once the image is rendered.
+
+Examples:
+
+  Basically identical to &lt;img src="..."&gt; tag:
+
+    <iron-image src="http://lorempixel.com/400/400"></iron-image>
+
+  Will letterbox the image to fit:
+
+    <iron-image style="width:400px; height:400px;" sizing="contain"
+      src="http://lorempixel.com/600/400"></iron-image>
+
+  Will crop the image to fit:
+
+    <iron-image style="width:400px; height:400px;" sizing="cover"
+      src="http://lorempixel.com/600/400"></iron-image>
+
+  Will show light-gray background until the image loads:
+
+    <iron-image style="width:400px; height:400px; background-color: lightgray;"
+      sizing="cover" preload src="http://lorempixel.com/600/400"></iron-image>
+
+  Will show a base-64 encoded placeholder image until the image loads:
+
+    <iron-image style="width:400px; height:400px;" placeholder="data:image/gif;base64,..."
+      sizing="cover" preload src="http://lorempixel.com/600/400"></iron-image>
+
+  Will fade the light-gray background out once the image is loaded:
+
+    <iron-image style="width:400px; height:400px; background-color: lightgray;"
+      sizing="cover" preload fade src="http://lorempixel.com/600/400"></iron-image>
+
+
+@group Iron Elements
+@element iron-image
+@demo demo/index.html
+-->
+
+<dom-module id="iron-image">
+
+  <style>
+
+    :host {
+      display: inline-block;
+      overflow: hidden;
+      position: relative;
+    }
+
+    :host([sizing]) #img {
+      display: none;
+    }
+
+    #placeholder {
+      background-color: inherit;
+      opacity: 1;
+    }
+
+    #placeholder.faded-out {
+      transition: opacity 0.5s linear;
+      opacity: 0;
+    }
+
+  </style>
+
+  <template>
+
+    <img id="img" role="none" hidden$="[[_computeImageVisibility(sizing)]]">
+    <div id="placeholder" hidden$="[[_computePlaceholderVisibility(fade,loaded,preload)]]" class$="[[_computePlaceholderClassName(fade,loaded,preload)]]"></div>
+    <content></content>
+
+  </template>
+
+</dom-module>
+
+<script>
+
+  Polymer({
+
+    is: 'iron-image',
+
+    properties: {
+      /**
+       * The URL of an image.
+       *
+       * @attribute src
+       * @type string
+       * @default ''
+       */
+      src: {
+        observer: '_srcChanged',
+        type: String,
+        value: ''
+      },
+
+      /**
+       * When true, the image is prevented from loading and any placeholder is
+       * shown.  This may be useful when a binding to the src property is known to
+       * be invalid, to prevent 404 requests.
+       *
+       * @attribute preventLoad
+       * @type boolean
+       * @default false
+       */
+      preventLoad: {
+        type: Boolean,
+        value: false
+      },
+
+      /**
+       * Sets a sizing option for the image.  Valid values are `contain` (full
+       * aspect ratio of the image is contained within the element and
+       * letterboxed) or `cover` (image is cropped in order to fully cover the
+       * bounds of the element), or `null` (default: image takes natural size).
+       *
+       * @attribute sizing
+       * @type string
+       * @default null
+       */
+      sizing: {
+        type: String,
+        value: null
+      },
+
+      /**
+       * When a sizing option is uzed (`cover` or `contain`), this determines
+       * how the image is aligned within the element bounds.
+       *
+       * @attribute position
+       * @type string
+       * @default 'center'
+       */
+      position: {
+        type: String,
+        value: 'center'
+      },
+
+      /**
+       * When `true`, any change to the `src` property will cause the `placeholder`
+       * image to be shown until the
+       *
+       * @attribute preload
+       * @type boolean
+       * @default false
+       */
+      preload: {
+        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.
+       *
+       * @attribute placeholder
+       * @type string
+       * @default null
+       */
+      placeholder: {
+        type: String,
+        value: null
+      },
+
+      /**
+       * When `preload` is true, setting `fade` to true will cause the image to
+       * fade into place.
+       *
+       * @attribute fade
+       * @type boolean
+       * @default false
+       */
+      fade: {
+        type: Boolean,
+        value: false
+      },
+
+      /**
+       * Read-only value that is true when the image is loaded.
+       *
+       * @attribute preloaded
+       * @type boolean
+       * @default false
+       */
+      loaded: {
+        notify: true,
+        type: Boolean,
+        value: false
+      },
+
+      /**
+       * Read-only value that tracks the loading state of the image when the `preload`
+       * option is used.
+       *
+       * @attribute loading
+       * @type boolean
+       * @default false
+       */
+      loading: {
+        notify: true,
+        type: Boolean,
+        value: false
+      },
+
+      /**
+       * Can be used to set the width of image (e.g. via binding); size may also be
+       * set via CSS.
+       *
+       * @attribute width
+       * @type number
+       * @default null
+       */
+      width: {
+        observer: '_widthChanged',
+        type: Number,
+        value: null
+      },
+
+      /**
+       * Can be used to set the height of image (e.g. via binding); size may also be
+       * set via CSS.
+       *
+       * @attribute height
+       * @type number
+       * @default null
+       */
+      height: {
+        observer: '_heightChanged',
+        type: Number,
+        value: null
+      },
+
+      _placeholderBackgroundUrl: {
+        type: String,
+        computed: '_computePlaceholderBackgroundUrl(preload,placeholder)',
+        observer: '_placeholderBackgroundUrlChanged'
+      },
+
+      requiresPreload: {
+        type: Boolean,
+        computed: '_computeRequiresPreload(preload,loaded)'
+      },
+
+      canLoad: {
+        type: Boolean,
+        computed: '_computeCanLoad(preventLoad, src)'
+      }
+
+    },
+
+    observers: [
+      '_transformChanged(sizing, position)',
+      '_loadBehaviorChanged(canLoad, preload, loaded)',
+      '_loadStateChanged(src, preload, loaded)',
+    ],
+
+    ready: function() {
+      if (!this.hasAttribute('role')) {
+        this.setAttribute('role', 'img');
+      }
+    },
+
+    _computeImageVisibility: function() {
+      return !!this.sizing;
+    },
+
+    _computePlaceholderVisibility: function() {
+      return !this.preload || (this.loaded && !this.fade);
+    },
+
+    _computePlaceholderClassName: function() {
+      if (!this.preload) {
+        return '';
+      }
+
+      var className = 'fit';
+      if (this.loaded && this.fade) {
+        className += ' faded-out';
+      }
+      return className;
+    },
+
+    _computePlaceholderBackgroundUrl: function() {
+      if (this.preload && this.placeholder) {
+        return 'url(' + this.placeholder + ')';
+      }
+
+      return null;
+    },
+
+    _computeRequiresPreload: function() {
+      return this.preload && !this.loaded;
+    },
+
+    _computeCanLoad: function() {
+      return Boolean(!this.preventLoad && this.src);
+    },
+
+    _widthChanged: function() {
+      this.style.width = isNaN(this.width) ? this.width : this.width + 'px';
+    },
+
+    _heightChanged: function() {
+      this.style.height = isNaN(this.height) ? this.height : this.height + 'px';
+    },
+
+    _srcChanged: function(newSrc, oldSrc) {
+      if (newSrc !== oldSrc) {
+        this.loaded = false;
+      }
+    },
+
+    _placeholderBackgroundUrlChanged: function() {
+      this.$.placeholder.style.backgroundImage =
+        this._placeholderBackgroundUrl;
+    },
+
+    _transformChanged: function() {
+      var placeholderStyle = this.$.placeholder.style;
+
+      this.style.backgroundSize =
+        placeholderStyle.backgroundSize = this.sizing;
+
+      this.style.backgroundPosition =
+        placeholderStyle.backgroundPosition =
+        this.sizing ? this.position : null;
+
+      this.style.backgroundRepeat =
+        placeholderStyle.backgroundRepeat =
+        this.sizing ? 'no-repeat' : null;
+    },
+
+    _loadBehaviorChanged: function() {
+      var img;
+
+      if (!this.canLoad) {
+        return;
+      }
+
+      if (this.requiresPreload) {
+        img = new Image();
+        img.src = this.src;
+
+        this.loading = true;
+
+        img.onload = function() {
+          this.loading = false;
+          this.loaded = true;
+        }.bind(this);
+      } else {
+        this.loaded = true;
+      }
+    },
+
+    _loadStateChanged: function() {
+      if (this.requiresPreload) {
+        return;
+      }
+
+      if (this.sizing) {
+        this.style.backgroundImage = this.src ? 'url(' + this.src + ')': '';
+      } else {
+        this.$.img.src = this.src || '';
+      }
+    }
+  });
+
+</script>