Arabic Formatting with ditroff/ffortid

Daniel M. Berry

Cheriton School of Computer Science
University of Waterloo
Waterloo, ON, Canada


This talk describes an Arabic formatting system that is able to format multilingual scientific documents, containing text in Arabic or Persian, as well as other languages, plus pictures, graphs, formulae, tables, bibliographical citations, and bibliographies. The system is an extension of ditroff/ffortid that is already capable of handling Hebrew in the context of multilingual scientific documents. ditroff/ffortid itself is a collection of pre- and postprocessors for the UNIX ditroff (Device Independent Typesetter RunOFF) formatter. The new system is built without changing ditroff itself. The extension consists of a new preprocessor, fonts, and a modified existing postprocessor.

The preprocessor transliterates from a phonetic rendition of Arabic using only the two cases of the Latin alphabet. The preprocessor assigns a position, stand-alone, connected-previous, connected-after, or connected-both, to each letter. It recognizes ligatures and assigns vertical positions to the optional diacritical marks. The preprocessor also permits input from a standard Arabic keyboard using the standard ASMO encoding. In any case, the output has each positioned letter or ligature and each diacritical mark encoded according to the font's encoding scheme.

The fonts are assumed to be designed to connect letters that should be connected when they are printed adjacent to each other.

The postprocessor is an enhancement of the ffortid program that arranges for right-to-left printing of identified right-to-left fonts. The major enhancement is stretching final letters of lines or words instead of inserting extra inter-word spaces, in order to justify the text.

As a self-test, the paper on which this talk is based was formatted using the described system, and it contains many examples of text written in Arabic, Hebrew, and English. The slides for this talk were extracted from the paper and were typeset with the same system.

Joint work with Johny Srouji