Chapter 13. PDFs inside-out
This chapter covers
- The history of PDF
- The Carousel Object System
- Low-level PDF manipulation
One of the initial strengths that made iText a success was that a developer was—and still is—able to create documents in the PDF format without having to know anything about the PDF specification. In the first versions of iText, you only had to know how a Chunk related to a Phrase, a Phrase to a Paragraph, and so on. The functionality was simple, but rather limited. Features that are specific to PDF, such as forms, optional content, and file attachments, weren’t supported yet. The more functionality was added, the more there was a need for developers to understand what PDF is about. That’s why we’re going to take a look inside.
But before you open up a PDF file, let’s look at why PDF was invented and how the format evolved from a de facto to an ISO standard.
We can’t talk about the history of PDF without talking about the history of the inventors of PDF, Adobe Systems Incorporated. Adobe was founded in 1982 by John Warnock and Chuck Geschke. Its first products were digital fonts, but nowadays Adobe offers a wide range of products and technologies. In this section, we’ll look at the ancestors of PDF, and you’ll learn about the different types of PDF that were created for different purposes.