<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.
+ of electronic documents for the USA but other countries have similar requirements.
</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.
+ Accessibility features are available only for the PDF output format and there are some
+ implementation limitations. Also, certain actions must be undertaken by the content creator
+ to ensure that FOP can create a truly accessible document.
</p>
</section>
<section>
<p>There are 3 ways to enable accessibility:</p>
<ol>
<li>
- <strong>Command line:</strong> The command line option -a turns on accessibility.
+ <strong>Command line:</strong> The command line option -a turns on accessibility:
<code>fop -a -fo mydocument.fo -pdf mydocument.pdf</code>
</li>
<li>
</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.
+ When accessibility is enabled, additional information relating to the logical structure of
+ the document is added to the PDF. That information allows the PDF viewer (or a
+ text-to-speech application) to retrieve the natural reading order of the document.
</p>
- <p>
- Hint: You may need to adjust the Java heap size in order to process larger files.
- </p>
+ <note>The processing of the logical structure is memory-hungry. You may need to adjust the
+ Java heap size in order to process larger files.</note>
</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.
+ your XSL-FO content in order to generate really accessible documents:
</p>
<ul>
- <li>Table cells require a table row as the parent.</li>
+ <li>Table cells must have a table row as their parent.</li>
<li>
- Ensure that the order of <code>fo:block-container</code> in a page corresponds to
- the reading order.
+ Images must have an alternate text: use the <code>fox:alt-text</code> extension attribute
+ (in the <a href="extensions.html#fox-namespace">fox namespace</a>) on
+ <code>fo:external-graphic</code> and <code>fo:instream-foreign-object</code> to specify a
+ short text describing the image.
</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>.
+ Ensure that the order of <code>fo:block-container</code> elements in a page corresponds to
+ the reading order.
</li>
<li>
Specify the natural language of the document using the language and country properties
- (or via the xml:lang shorthand property).
+ (or via the <code>xml:lang</code> 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.
+ Accessible PDFs can be tested, for example, using Adobe Acrobat Professional. Its
+ Accessibility Check feature creates a report indicating any deficiencies with a PDF
+ document. Alternatively, you can just let a screen reader read the document aloud.
</p>
</section>
<section id="limitations">
<title>Limitations</title>
<p>
- Accessibility support in Apache FOP is relatively new, so naturally, there are certain
+ Accessibility support in Apache FOP is relatively new, so 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
+ The natural language can currently only be specified at 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>
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.
+ SVGs is not accessible. It's only possible to work with <code>fox:alt-text</code>.
</li>
<li>
XSL-FO's role property is currently not supported. It could theoretically be used to
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.
+ Many resources providing guidance about creating accessible documents can be found on the
+ web. Here are a few links, along 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")
+ <a href="http://partners.adobe.com/public/developer/en/pdf/PDFReference.pdf">PDF
+ Reference 1.4</a> (look up chapters 9.7 "Tagged PDF" and 9.8 "Accessibility Support")
</li>
+ <li><a href="pdfa.html">PDF/A support in Apache FOP</a></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>
projects / xmlgraphics-fop.git / commitdiff