third_party/polymer/components-chromium/core-image/core-image.html

   1 <!--
   2 Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
   3 This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
   4 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
   5 The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
   6 Code distributed by Google as part of the polymer project is also
   7 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
   8 --><!--
   9 `core-image` is an element for displaying an image that provides useful sizing and
  10 preloading options not found on the standard `<img>` tag.
  11
  12 The `sizing` option allows the image to be either cropped (`cover`) or
  13 letterboxed (`contain`) to fill a fixed user-size placed on the element.
  14
  15 The `preload` option prevents the browser from rendering the image until the
  16 image is fully loaded.  In the interim, either the element's CSS `background-color`
  17 can be be used as the placeholder, or the `placeholder` property can be
  18 set to a URL (preferably a data-URI, for instant rendering) for an
  19 placeholder image.
  20
  21 The `fade` option (only valid when `preload` is set) will cause the placeholder
  22 image/color to be faded out once the image is rendered.
  23
  24 Examples:
  25
  26   Basically identical to &lt;img src="..."&gt; tag:
  27
  28     <core-image src="http://lorempixel.com/400/400"></core-image>
  29
  30   Will letterbox the image to fit:
  31
  32     <core-image style="width:400px; height:400px;" sizing="contain"
  33       src="http://lorempixel.com/600/400"></core-image>
  34
  35   Will crop the image to fit:
  36
  37     <core-image style="width:400px; height:400px;" sizing="cover"
  38       src="http://lorempixel.com/600/400"></core-image>
  39
  40   Will show light-gray background until the image loads:
  41
  42     <core-image style="width:400px; height:400px; background-color: lightgray;"
  43       sizing="cover" preload src="http://lorempixel.com/600/400"></core-image>
  44
  45   Will show a base-64 encoded placeholder image until the image loads:
  46
  47     <core-image style="width:400px; height:400px;" placeholder="data:image/gif;base64,..."
  48       sizing="cover" preload src="http://lorempixel.com/600/400"></core-image>
  49
  50   Will fade the light-gray background out once the image is loaded:
  51
  52     <core-image style="width:400px; height:400px; background-color: lightgray;"
  53       sizing="cover" preload fade src="http://lorempixel.com/600/400"></core-image>
  54
  55
  56 @group Polymer Core Elements
  57 @element core-image
  58 @homepage github.io
  59 --><html><head><link rel="import" href="../polymer/polymer.html">
  60
  61 </head><body><polymer-element name="core-image" assetpath="">
  62 <template>
  63   <link rel="stylesheet" href="core-image.css">
  64   <template if="{{!sizing}}">
  65     <img id="img">
  66   </template>
  67   <template if="{{preload &amp;&amp; fade}}">
  68     <div id="placeholder" fit=""></div>
  69   </template>
  70   <content></content>
  71 </template>
  72
  73 </polymer-element>
  74 <script src="core-image-extracted.js"></script></body></html>