VDP

VDP stands for Variable Data Printing.

Remember the old days when the invoices were printed on paper that already contained the company logo, headers and footers?

The main reason for using pre-printed paper was the processing speed - you don't have to print that for every page. You will also save money because pre-printed paper is printed using an offset process (think newspapers) that is costs less.

Using the latest rendering engines you can achieve the same effect - a smart rendering engine will create an "overlay" that is cached in the printer's memory and printed very efficiently.

XSL-FO Resources

Here are a couple of XSL-FO resources:

Introduction to XSL-FO and some generic XML topics

XSL-FO Tutorial on ecrion.com

XSL-FO Questions and answers on stackoverflow.com

XSL-FO 2.0 working draft is now available

The World Wide Web Consortium (W3C) XSL-FO subgroup of the XSL Working Group has published a First Public Working Draft of "Design Notes for Extensible Stylesheet Language (XSL) 2.0," which contains initial and early work on XSL-FO 2.0. XSL-FO defines an XML vocabulary for formatting and layout of XML documents; use XSLT to transform documents into XSL-FO for on-screen or paper formatting, for example into PDF. Public comments are requested, both from users and implementors of XSL 1.x and from people who have been waiting for new features before using XSL-FO. http://www.w3.org/TR/xslfo20/

Getting started with XSL-FO

It seems these days that a lot of people are trying to find a shortcut to a classical dilemma: How do I convert XML to PDF?
To many, the solution is to convert XML to HTML using a stylesheet, and then use some free tool to generate PDF. Which, although is sounds easy, it is also pretty silly, as I came to discover a while ago when a customer asked for a footnote to be attached to a chart in a page.
Footnotes don't have a HTML equivalent - you can implement something that may look like a footnote, but because a footnote must follow proximity rules (stay on the same page as the content it annotates) you cannot implement reliable footnotes using HTML.
This, and the absence of page numbers and page layouts in general made me look for another way to convert XML to PDF.
It turned out that the stylesheet that I was using can be adapted easily to generate XSL-FO (or FO).
FO stands for Formatting Objects; it's an XML language, which in addition to being able to create documents which contain tables, paragraphs and images, it also contains pagination related tags.

I use Ecrion's XML to PDF software because it has a pretty decent designer and it's the fastest XML to PDF engine that uses open standards that I know of.