Prawn is a pure Ruby PDF generation library that aims to make low level PDF generation tasks easy. It is currently under active development, and could be considered somewhere between alpha and beta quality software.

FormulatePro helps you open and write on PDF documents. You can fill out any PDF form document, drop in graphics, scribble with the mouse or a tablet, save and print.

FormulatePro requires Mac OS X version 10.4 Tiger or higher.