Working with links

Links in PDF documents are interactive elements that represent either a hypertext link to a destination in the same (or other) PDF document or an action to be performed. In PDF, links are a type of annotation.

You can use the Links element to specify the following results:

•	Export of a representation of the links in a PDF document into XFDF.

•	Import of links in XFDF format into a PDF document. These links can replace or add to the existing links in the document.

•	Removal of the links in a document by using the NoLinks element.

This example extracts the links from doc1.pdf and returns the data to the client as an XFDF stream specified by the Links result element.

Example: Exporting links as XFDF

<Links result="links1.xfdf">

	<PDF source="doc1.pdf" />

</Links>

If a Links element has multiple PDF source elements as children, the children are effectively assembled into a single document from which the link information is exported, as in this example. This means that any links in doc1.pdf or doc2.pdf that refer to the other document (that is, cross-document links) will be rationalized in the result document. See Rationalizing links for details.

Example: Exporting links from multiple sources

<Links result="links1.xfdf">

	<PDF source="doc1.pdf" />

	<PDF source="doc1a.pdf" />

</Links>

You can save links1.xfdf to use in a separate workflow or within the same DDX. In the following example, the result document doc3.pdf imports the links from links1.xfdf. Because the PDF and Links source elements are siblings, the links from both sources are aggregated and included in the result.

Example: Adding links

<PDF result="doc3.pdf">

	<PDF source="doc2.pdf" />

	<Links source="links1.xfdf" />

</PDF>

In this example, the Links element is a child of the PDF source and therefore the links from links1.xfdf replace the links in doc2.pdf. The result is returned as doc3.pdf.

Example: Replacing links

<PDF result="doc3.pdf">

	<PDF source="doc2.pdf">

		<Links source="links1.xfdf" />

	</PDF>

</PDF>

In some cases, you can skip the step of exporting links to XFDF and then importing them if you do not need the XFDF outside the current DDX document. You can use a links filter element to effectively export and import within a single result element. A filter element is like a result in that its content is provided by its child elements, and it is like a source in that it provides content to its parent. For more information, see Filter elements.

In the following example, the Links filter element can be thought of as containing the links from its child, doc1.pdf. Those links are then imported into the result document doc2.pdf.

Example: Using a links filter element

<PDF result="doc2.pdf">

	<Links>

		<PDF> source="doc1.pdf/>

	</Links>

</PDF>

Current page: http://livedocs.adobe.com/livecycle/es/sdkHelp/programmer/sdkHelp/assemblePDFComments.98.5.html