PDF::Core is a pure Ruby library to render PDF documents.

It supports several PDF features, such as among others:
 * low-level annotation
 * istream objects and stream filters
 * NameTree
 * object repository
 * object serialization
 * indirect objects
 * page geometries

It is used internally by Prawn (provided in the rubygems-prawn package),
a Ruby PDF generation library.

WWW: http://prawnpdf.org/
WWW: https://github.com/prawnpdf/pdf-core