GNU PDF Library
From the Statement of Purpose:
The GNU PDF Library provides functions to read and write PDF documents conforming to the PDF 1.7 specification. This includes visualization (retrieving of bitmaps with rasterized page contents) and interactive features such as annotations and interactive forms. The library also support the generation of specific subsets of PDF conforming to the ISO standards PDF/A, PDF/X and ISO 32000.
Right now the library is under heavy development and we have not released a version yet.
Please see the Library Page for more information.
The code-named GNU Juggler will be a full-fledged PDF viewer and editor making use of the GNU PDF Library. Right now we are busy in the development of the library and the GNU Juggler is not even started.
Please see the Juggler Page for more information.
PDF Knowledge Database
As we develop the GNU PDF Library we are generating free documentation about many parts of the PDF specification, the several existing PDF standards, PDF implementation issues, etc. That documentation is available in this webpage and organized into the PDF Knowledge Database.
Please see the PDF Knowledge Database for more information.