links to this page:
Portable Document Format (PDF)
PDF file - the structure
Last updated at 10:58 am UTC on 8 May 2017
A PDF file mainly consists of a tree where each node is an object. The object is one of the eight PDF data types:
strings
arrays
numbers (integer and real)
boolean values (true/false)
name objects
associated arrays (called dictionaries)
streams
a null object.
