PDF::Extractor is a library that provides high level access to the text objects of a PDF document.

It is actually a simple wrapper around the pdftohtml command with its '-xml' option, so you need the pdftohtml command in your path to be able to use this library.
The pdftohtml command is written by Mikhail Kruk (originally written by Gueorgui Ovtcharov and Rainer Dorsch):

http://pdftohtml.sourceforge.net

If you need to have direct (low level) access to a PDF, use pdf-reader instead:

http://github.com/yob/pdf-reader/tree/master

Usage:

  document = PDF::Extractor.open('test.pdf')
  document.elements.each do |element|
    puts "#{element.left}, #{element.top}\t'#{element.content}'"
  end