A new approach to coding displayed mathematics for photocomposition

An applications program called TEXTCOMP has been developed by the Technical information and Documentation Division. Jet Propulsion Laboratory (JPL), for use in conjunction with Alphanumeric Publication Systems´ Comp-2 photocomposition program. TEXTCOMP, written in the Comp-2 language, is designed to accommodate the wide variety of complex page formats and other production requirements typically encountered in JPL´s scientific and engineering documentation. This documentation ranges from straight textual narratives to exceedingly complex technical explanations and descriptions with significant amounts of displayed mathematics. Inherent in all displayed mathematics is an unlimited variety in alignments, horizontal and vertical spacing, and widths and heights of individual characters. Since the photocomposition system for which the TEXTCOMP applications program was written was not designed to perform automatically the intricate calculations required to accommodate these variations, the initial applicability of the program was limited largely to documentation without displayed mathematics. A coding approach has been developed whereby displayed mathematics can now be photocomposed in place within the text using the TEXTCOMP program. Although this coding approach was developed specifically for use with TEXTCOMP and Alphanumeric´s Comp-2 photocomposition system, it is applicable for use with any photocomposition system. The approach described is simple, but unconventional; the codes are demanding, but easily manageable. The most attractive aspect is that absolutely no physical measurement of characters is required.