Overlaying and underlaying pages

Overlays and underlays specify PDF page content to be added to pages in a document. They differ from watermarks and backgrounds in the following ways:

•	The content must come from PDF pages and cannot be specified using styled text.

•	Once added, they are indistinguishable from other page content. Therefore, you cannot remove content that was added to a page by means of an overlay or underlay.

•	You can add multiple overlays or underlays to a page or pages.

You can use the PageOverlay and PageUnderlay elements to add page content over or under the existing content, respectively. You specify them as child elements of the PDF elements identifying the destination pages.

Note: The Assembler service supports only unfiltered data, ASCIIHex filters, and ASCII85 filters for inline images on overlay pages. All other filters in inline images are unsupported in these operations.

This example overlays page 5 from doc2.pdf onto all but the first page of doc1.pdf.

Example: Overlaying pages

<PDF result="doc3.pdf">

	<PDF source="doc1.pdf" pages="2-last">

		<PageOverlay>

			<PDF source="doc2.pdf" pages="5"/>

		</PageOverlay>

	</PDF>

</PDF>

In this example, the parent of the PageOverlay element is a PDF source element that specifies the pages to which the overlay should apply. The child of the PageOverlay element specifies the document from which the overlay should come. In the example, it specifies a single page (5). If it does not specify a single page, the first page of the range is used.

Items such as bookmarks, page labels, document structure, and document-level JavaScript code are not copied from overlays or underlays to their destination document. Any page properties that conflict with the destination page are ignored. Form fields and annotations may be copied by specifying a value of true for the embedFormsAndAnnots attribute (the default is false). In this case, form-level JavaScript code associated with forms on the page is included with the copied form.

The source (overlay or underlay) page is placed relative to the destination page so that the user space origin (lower left corner) of both pages coincide. If the source page size is smaller than the destination page size, no content is removed; in effect, the page size for the source overlay page is made larger.

Current page: http://livedocs.adobe.com/livecycle/es/sdkHelp/programmer/sdkHelp/assemblePDFPage_content.103.6.html