7.2. Optimal PDF

HTML is quite limited when it comes to advanced formatting capabilities (although this has somewhat changed with the advent of CSS, see Section 4.14 and Section 7.1.8). On the other side, the layout of a PDF document remains unchanged, regardless of the output medium, be it monitor, or printer. It retains all its typographic finesse and is not (at least easily) modifiable. These properties, together with the availability of free PDF readers, like Acrobat® Reader or xpdf, have rendered PDF a very popular format.

But PDF is not a simple print format. It incorporates features that bear similarities to HTML : you can insert hypertext links to point either to some other place in the same document (a cross-reference), to other PDF documents, or even to WWW pages. You can have the Table of Contents as a link tree to the left (“bookmarks”), extended Document Information (author, keywords, creator, embedded fonts etc.), or thumbnails (we will talk in Section 7.2.11 for the details of thumbnail generation), which are small pictograms of the document's pages to aid visual navigation.

In this section I will discuss the details of incorporating all these advanced features in the PDF document generated by DocBook through LyX.