Passepartout is an open source desktop publishing application for X-Windows (Unix). The goal is to provide a simple and user-friendly, yet powerful tool for creating printed material. Passepartout combines a WYSIWYG layout editor with a high-quality typesetting engine. Passepartout is released under a BSD license. The Passepartout webpage can be found at http://www.stacken.kth.se/project/pptout/.
You do not use Passepartout for writing text, because it is only a layout editor. Basically speaking, Passepartout is in the business of taking the different parts that make up a page, such as text, photos, graphics, and "gluing" them on piece of paper. Passepartout can import from several different bitmapped image formats as well as EPS files. You write the text in your favorite text editor (e.g. Emacs or VI) in an XML-based format. The XML file is then typeset using a typesetting engine called xml2ps.