pdfTeX

__NOTOC__ The computer program pdfTeX, sometimes typeset as '''''', is an extension of Knuth's typesetting program TeX, and was originally written and developed into a publicly usable product by as a part of the work for his PhD thesis at the Faculty of Informatics, Masaryk University, Brno, Czech Republic. The idea of making this extension to TeX was conceived during the early 1990s, when Jiří Zlatuška and Phil Taylor discussed some developmental ideas with Donald Knuth at Stanford University. Knuth later met Hàn Thế Thành in Brno during his visit to the Faculty of Informatics to receive an honorary doctorate from Masaryk University.

Two prominent characteristics of pdfTeX are character protrusion, which generalizes the concept of hanging punctuation, and font expansion, an implementation of Hermann Zapf's ideas for improving the grayness of a typeset page. Both extend the core paragraph breaking routine. They are discussed in Thành's PhD thesis.