Sunday, October 28, 2007
This chapter covers everything about the syntax of PDF at the object, file, and document level. It sets the stage for subsequent chapters, which describe how the contents of a PDF file are interpreted as page descriptions, interactive navigational aids, and application-level logical structure.
PDF syntax is best understood by thinking of it in four parts, as shown in Figure 3.1:
•Objects. A PDF document is a data structure composed from a small set of basic types of data objects. Section 3.1, "Lexical Conventions," describes the character set used to write objects and other syntactic elements. Section 3.2, "Objects," describes the syntax and essential properties of the objects. Section 3.2.7, "Stream Objects," provides complete details of the most complex data type, the stream object.
•File structure. The PDF file structure determines how objects are stored in a PDF file, how they are accessed, and how they are updated. This structure is independent of the semantics of the objects. Section 3.4, "File Structure," describes the file structure. Section 3.5, "Encryption," describes a file-level mechanism for protecting a document’s contents from unauthorized access.
•Document structure. The PDF document structure specifies how the basic object types are used to represent components of a PDF document: pages, fonts, annotations, and so forth. Section 3.6, "Document Structure," describes the overall document structure; later chapters address the detailed semantics of the components.
•Content streams. A PDF content stream contains a sequence of instructions describing the appearance of a page or other graphical entity. These instructions, while also represented as objects, are conceptually distinct from the objects that represent the document structure and are described separately. Section 3.7, "Content Streams and Resources," discusses PDF content streams and their associated resources.
full pdf syntax
PDF Reference, Sixth Edition, version 1.7 (PDF, 31.0M)