Book excerpt: At last, here’s an approachable introduction to the widely used Portable Document Format. PDFs are everywhere, both online and in printed form, but few people take advantage of the useful features or grasp the nuances of this format. This concise book provides a hands-on tour of the world’s leading page-description language for programmers, power users, and professionals in the search, electronic publishing, and printing industries. Illustrated with lots of examples, this book is the documentation you need to fully understand PDF. Build a simple PDF file from scratch in a text editor Learn the layout and content of a PDF file, as well as the syntax of its objects Examine the logical structure of PDF objects, and learn how pages and their resources are arranged into a document Create vector graphics and raster images in PDF, and deal with transparency, color spaces, and patterns Explore PDF operators for building and showing text strings Get up to speed on bookmarks, metadata, hyperlinks, annotations, and file attachments Learn how encryption and document permissions work in PDF Use the pdftk program to process PDF files from the command line