Quill and Parchment
Quill is a what-you-see-is-what-you-need document editor with clean display of your content and subtle presentation of semantic markup. It also offers a live preview and an outline to help you navigate.
Parchment is a simple but powerful rendering back-end which takes these documents and outputs them as PDF files. Different document types have different rendering engines (ie, stylesheets) customized for the purpose.
You can run the user interface via quill on the command line, or you can double click on a .parchment document in Nautilus; the Parchment renderer is built into Quill, of course (Ctrl+P, baby), but can also be run independently from the command line as render.
You can learn more about the background of the project and why we wanted to work on this.
Everybody loves a screenshot. We've got lots :) including the editor, navigation supoprt, and configuring the render engine.
Documentation about the on-disk file format that Quill stores documents in.
Quill and Parchment is still a young project, but it represents over two years of design and engineering (not to mention that a great deal of the work on the Java GTK bindings over the last 18 months was specifically to support us to writing the editor UI and rendering engine).
You are, of course, welcome to build the code and try out the app. However, while the Parchment renderer is in good shape, the Quill editor UI isn't quite ready for other people to use yet (better to be honest about that than have you asking why there's no button to add a new chapter). The file format is stable, and people in the java-gnome community have been testing the codebase and some not-insignificant documents have been written with Quill. We hope to make our first proper release this month.
Quill and Parchment is being written by Andrew Cowie, based on design input from Peter Miller, Jon Corbet, Devdas Bhagat, Stewart Smith, Paul Drain, Serkan Kaba, Kenneth Prugh, and Guillaume Mazoyer. If you would like to ask questions, you can contact Andrew as AfC in #java-gnome on the irc.gimp.net IRC network.