As PDF is growing in acceptance and is even going to be an international standard, the lack of free/open source software pdf writer/reader which
are fully compatible with the PDF standard is becoming more and more important.
But now GNU has started a new project
The goal of the GNU PDF project is to develop and provide a free, high-quality, complete and portable set of libraries and programs to manage the PDF file format, and associated technologies.
You can even donate to help them create the software faster…
There are a lot of FOSS programs which can handle PDF. So why do wee need a new software (library)?
They have a page explaining it…
Mainly its because there is no GPLv3 software, existing programs are written in C++ and not C (issue for mobil systems) and the PDF compliance of the software.