Graphics Programs Reference
In-Depth Information
CHAPTER 1
Introduction
The Portable Document Format (PDF) is the world's leading language for describing
the printed page, and the first one equally suitable for paper and online use. In this
chapter, we take a tour of its uses, features, and history. We look at some useful free
software and resources, some of which we'll use later in this topic.
A Little History
Today we take the high fidelity exchange of documents for granted, knowing that a
document sent here will appear the same there and vice versa, and that it may be dis-
played equally on screen and on paper. This was not always so.
Page Description Languages
We could pass documents between users, and from user to printer, as a series of bitmap
pictures (e.g., TIFF or PNG), one for each page. However, this doesn't allow for any
structure to be retained, precludes scaling to different paper sizes or resolutions without
loss of quality, involves huge file sizes, and so on.
A
page description language
like PDF is way of describing the contents (text and graph-
ics) of a printed or onscreen page using highly structured data, often with extra
metadata
describing various aspects of the document (such as printing information or
textual annotations or how it is to be viewed or printed). This way, decisions about
how the document is rasterized (converted to pixels by a printer or on screen) can be
left until the end of the production process. A PDF file can contain text and associated
font definitions, vector and bitmap graphics, navigation (such as hyperlinks and book-
marks), and interactive forms.
