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

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   2 Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
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   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
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   9 <!--
  10
  11 The `core-style` element helps manage styling inside other elements and can
  12 be used to make themes. The `core-style` element can be either a producer
  13 or consumer of styling. If it has its `id` property set, it's a producer.
  14 Elements that are producers should include css styling as their text content.
  15 If a `core-style` has its `ref` property set, it's a consumer. A `core-style`
  16 typically sets its `ref` property to the value of the `id` property of the
  17 `core-style` it wants to use. This allows a single producer to be used in
  18 multiple places, for example, in many different elements.
  19
  20 It's common to place `core-style` producer elements inside HTMLImports.
  21 Remote stylesheets should be included this way, the &#64;import css mechanism is
  22 not currently supported.
  23
  24 Here's a basic example:
  25
  26     <polymer-element name="x-test" noscript>
  27       <template>
  28         <core-style ref="x-test"></core-style>
  29         <content></content>
  30       </template>
  31     </polymer-element>
  32
  33 The `x-test` element above will be styled by any `core-style` elements that have
  34 `id` set to `x-test`. These `core-style` producers are separate from the element
  35 definition, allowing a user of the element to style it independent of the author's
  36 styling. For example:
  37
  38     <core-style id="x-test">
  39       :host {
  40         backgound-color: steelblue;
  41       }
  42     </core-style>
  43
  44 The content of the `x-test` `core-style` producer gets included inside the
  45 shadowRoot of the `x-test` element. If the content of the `x-test` producer
  46 `core-style` changes, all consumers of it are automatically kept in sync. This
  47 allows updating styling on the fly.
  48
  49 The `core-style` element also supports bindings and it is the producer
  50 `core-style` element is the model for its content. Here's an example:
  51
  52     <core-style id="x-test">
  53       :host {
  54         background-color: {{myColor}};
  55       }
  56     </core-style>
  57     <script>
  58       document._currentScript.ownerDocument.getElementById('x-test').myColor = 'orange';
  59     </script>
  60
  61 Finally, to facilitate sharing data between `core-style` elements, all
  62 `core-style` elements have a `g` property which is set to the global
  63 `CoreStyle.g`. Here's an example:
  64
  65     <core-style id="x-test">
  66       :host {
  67         background-color: {{g.myColor}};
  68       }
  69     </core-style>
  70     <script>
  71       CoreStyle.g.myColor = 'tomato';
  72     </script>
  73
  74 Finally, one `core-style` can be nested inside another. The `core-style`
  75 element has a `list` property which is a map of all the `core-style` producers.
  76 A `core-style` producer's content is available via its `cssText` property.
  77 Putting this together:
  78
  79     <core-style id="common">
  80       :host {
  81         font-family: sans-serif;
  82       }
  83     </core-style>
  84
  85     <core-style id="x-test">
  86       {{list.common.cssText}}
  87
  88       :host {
  89         background-color: {{g.myColor}};
  90       }
  91     </core-style>
  92
  93
  94 @group Polymer Core Elements
  95 @element core-style
  96 @homepage github.io
  97 -->
  98
  99 <link rel="import" href="../polymer/polymer.html">
 100
 101 <polymer-element name="core-style" hidden assetpath="">
 102
 103 </polymer-element>
 104 <script src="core-style-extracted.js"></script>