Chapter 4: XSL-FO

Overview

This chapter presents a reference and detailed examples of using the features of XSL-FO (e Xtensible Stylesheet Language-F ormatting Objects). It is used to specify the formatting semantics of documents using an XML format.

XSL-FO is used to produce formatted output from an XML data source. One problem of Web based applications has been the difficulty of producing quality printable output to create presentation quality documents available from the browser. XSL-FO, in conjunction with Scalable Vector Graphics (Chapter 5), gives you the tools to provide this service to users in common Web formats.

XSL-FO builds on the other Web based styling technologies like Cascading Style Sheets (CSS(2)), Document Style Semantics and Specification Language (DSSSL). The W3C used these technologies, which were aimed primarily for browser rendering to produce a specification for paginated output not solely targeted to the Web browser. This led to the W3C specification for XSL, which includes XSL-FO and for e Xtensible Stylesheet Language Transformation (XSLT).

Although this chapter concentrates on producing output documents for printing, the XSL-FO specification provides for other mediums of electronic communication such as text to speech. XSLFO also includes multilingual support including options for right-to-left, bottom-to-top languages.

At the moment, Web browsers cannot directly display pages marked up with XML-FO objects. To produce output from XSL-FO documents, you use an XSL-FO processor. Examples of the common output supported by free-to-download processors include PDF, Text, PCL and PS.

If you wish to work through the examples presented in this chapter, you need several prerequisites. The applications required for the examples plus alternative applications are listed and examined later in the chapter.

Initially, I present a detailed overview of XSL, where XSL-FO fits in to the XML family, examples of where XSL-FO can be used and a detailed overview of the syntax and properties of the key areas of the XSL-FO implementation.