<refentry xmlns="http://docbook.org/ns/docbook"
          xmlns:xlink="http://www.w3.org/1999/xlink"
          xmlns:xi="http://www.w3.org/2001/XInclude"
          xmlns:src="http://nwalsh.com/xmlns/litprog/fragment"
          xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
          version="5.0" xml:id="insert.olink.pdf.frag">
<refmeta>
<refentrytitle>insert.olink.pdf.frag</refentrytitle>
<refmiscinfo class="other" otherclass="datatype">boolean</refmiscinfo>
</refmeta>
<refnamediv>
<refname>insert.olink.pdf.frag</refname>
<refpurpose>Add fragment identifiers for links into PDF files</refpurpose>
</refnamediv>

<refsynopsisdiv>
<src:fragment xml:id="insert.olink.pdf.frag.frag">
<xsl:param name="insert.olink.pdf.frag" select="0"/>
</src:fragment>
</refsynopsisdiv>

<refsection><info><title>Description</title></info>

<para>The value of this parameter determines whether
the cross reference URIs to PDF documents made with
<tag>olink</tag> will 
include fragment identifiers.
</para>

<para>When forming a URI to link to a PDF document,
a fragment identifier (typically a '#' followed by an
id value) appended to the PDF filename can be used by
the PDF viewer to open
the PDF file to a location within the document instead of
the first page.
However, not all PDF files have id
values embedded in them, and not all PDF viewers can
handle fragment identifiers. 
</para>

<para>If <parameter>insert.olink.pdf.frag</parameter> is set
to a non-zero value, then any olink targeting a
PDF file will have the fragment identifier appended to the URI.
The URI is formed by concatenating the value of the
<parameter>olink.base.uri</parameter> parameter, the
value of the <tag class="attribute">baseuri</tag>
attribute from the <tag class="element">document</tag>
element in the olink database with the matching
<tag class="attribute">targetdoc</tag> value,
and the value of the <tag class="attribute">href</tag>
attribute for the targeted element in the olink database.
The <tag class="attribute">href</tag> attribute
contains the fragment identifier.
</para>

<para>If <parameter>insert.olink.pdf.frag</parameter> is set
to zero (the default value), then 
the <tag class="attribute">href</tag> attribute
from the olink database
is not appended to PDF olinks, so the fragment identifier is left off.
A PDF olink is any olink for which the
<tag class="attribute">baseuri</tag> attribute
from the matching <tag class="element">document</tag>
element in the olink database ends with '.pdf'.
Any other olinks will still have the fragment identifier added.
</para>
</refsection>
</refentry>
