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							<?xml version="1.0" standalone="no"?>
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<!-- $Id$ -->
<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V2.0//EN" "document-v20.dtd">
<document>
  <header>
    <title>Accessibility</title>
  </header>
  <body>
    <section id="overview">
      <title>Overview</title>
      <p>
        This page describes the
        <a href="http://en.wikipedia.org/wiki/Accessibility">accessibility</a>
        features of Apache FOP.
        <a href="http://www.section508.gov/">Section 508</a> defines accessibility in the context
        of electronic documents for the US but it impacts also other countries.
      </p>
      <p>
        These features are concentrated exclusively on PDF output
        (Tagged PDF). There are certain implementation limitations that need to be observed
        and certain actions are necessary by the content creator to ensure that FOP can create
        a truly accessible document. 
      </p>
    </section>
    <section>
      <title>Enabling accessibility</title>
      <p>There are 3 ways to enable accessibility:</p>
      <ol>
        <li>
          <strong>Command line:</strong> The command line option -a turns on accessibility.
          <code>fop -a -fo mydocument.fo -pdf mydocument.pdf</code>            
        </li>
        <li>
          <strong>Embedding:</strong> <code>userAgent.setAccessibility(true);</code>
        </li>
        <li>
          <strong>Optional setting in fop.xconf file:</strong>
          <pre>
          &lt;fop version="1.0"&gt;
              &lt;accessibility&gt;true&lt;/accessibility&gt;
              ...
          &lt;/fop&gt;
          </pre>
        </li>
      </ol>
      <p>
        As mentioned, enabling accessibility currently only changes the way PDFs are generated.
        Internally, FOP maintains a reduced structure tree of the document so the target format
        viewer can ultimately reconstruct the natural reading order of the document. This is
        important for document readers that produce an aural representation of the content.
      </p>
      <p>
        Hint: You may need to adjust the Java heap size in order to process larger files.
      </p> 
    </section>
    <section id="source">
      <title>Changes to your XSL-FO input files</title>
      <p>
        Apache FOP cannot automatically generate accessible PDFs. Some of the work can only be
        performed by the content provider. Following are some changes that may be necessary to
        your XSL-FO content so the generate documents that are truly accessible.
      </p>
      <ul>
        <li>Table cells require a table row as the parent.</li>
        <li>
          Ensure that the order of <code>fo:block-container</code> in a page corresponds to
          the reading order.
        </li>
        <li>
          Alternate text for images: The attribute <code>fox:alt-text</code> has been added
          for <code>fo:external-graphic</code> and <code>fo:instream-foreign-object</code>.
        </li>
        <li>
          Specify the natural language of the document using the language and country properties
          (or via the xml:lang shorthand property).
        </li>
      </ul>
    </section>
    <section id="testing">
      <title>Testing</title>
      <p>
        Accessible PDFs can be tested, for example, using Adobe Acrobat Professional. Its
        Accessibility Check creates a report indicating any deficiencies with a PDF document.
        Alternatively, you can just let a screen reader read the document out aloud.
      </p>
    </section>
    <section id="limitations">
      <title>Limitations</title>
      <p>
        Accessibility support in Apache FOP is relatively new, so naturally, there are certain
        limitations. Please help us identify and close any gaps.
      </p>
      <ul>
        <li>
          The natural language can currently only be specified on the page-sequence level. The
          document language is derived from the language of the first page-sequence. It is
          currently not possible to override the language inside the content below the
          page-sequence level.
        </li>
        <li>
          It's currently not possible to specify the expanded form of an abbreviation or acronym.
        </li>
        <li>
          SVG graphics (or images in general) are treated as a single figure. Text contained in
          SVGs is not accessible. It's only possible to work with fox:alt-text.
        </li>
        <li>
          XSL-FO's role property is currently not supported. It could theoretically be used to
          differentiate between headings and normal text. At the moment, the two are simply
          identified as paragraphs.
        </li>
        <li>
          The side regions (region-before, region-after etc.) are currently not specially
          identified. Screen readers may read their content at page changes.
        </li>
        <li>
          The accessibility features are only available with PDF output and only if the
          new output implementation based on the intermediate format (PDFDocumentHandler) is used.
          Accessibility (Tagged PDF) is not supported by the legacy PDFRenderer.
        </li>
      </ul>
    </section>
    <section id="links">
      <title>Related Links</title>
      <p>
        We don't provide a comprehensive guide to create accessible documents. Below are some
        links with additional resources around the topic.
      </p>
      <ul>
        <li><a href="pdfa.html">PDF/A support in Apache FOP</a></li>
        <li><a href="http://www.section508.gov/">US Government - Website on Section 508</a></li>
        <li><a href="http://en.wikipedia.org/wiki/Accessibility">Wikipedia on Accessibility in general</a></li>
        <li><a href="http://en.wikipedia.org/wiki/Portable_Document_Format#Accessibility">Wikipedia on Accessibility in PDF</a></li>
        <li>
          <a href="http://partners.adobe.com/public/developer/en/pdf/PDFReference.pdf">PDF Reference 1.4</a> 
          (lookup chapters 9.7 "Tagged PDF" and 9.8 "Accessibility Support")
        </li>
        <li><a href="http://wiki.apache.org/xmlgraphics-fop/PDF_Accessibility">Developer-oriented details on the accessibility features (on the Wiki)</a></li>
      </ul>
    </section>
  </body>
</document>