Page:NBS Technical Note 11176 (1983) (IAutilityprogramsf1176dick).djvu/12

 incorporation of the Hershey character fonts as user defined characters under the Hewlett-Packard Graphics Language (15), and in a system for use on the Apple II computer system. It is this latter application which is the subject of this report.

Extensive use of the Hershey characters was made in 1981 by Claude A. Kagan who succeeded in adapting them for a variety of microcomputer systems, including the Apple II operating under CPM (I6). A more recent application of the Hershey character set has been made by Daniel Macero and associates (17) who have modified a line printer to provide a resolution of 100 dots-per-inch horizontally and 72 dots-per-inch vertically.

THE CURRENT PROGRAMS

The present report details a technique for using the Hershey characters with the Apple II computer system operating under the Apple Disk Operating System, DOS 3.3 (18). Although the High Resolution Character Generator Routine supplied as part of the Applesoft Toolkit (19) provides for the creation and retrieval of characters and special symbols, these characters are limited to a 7x8 dot matrix format and are designed to be used on the high resolution graphics screen.

Consequently, we present in this report two programs that will allow the storage of the Hershey characters in a compact format as text files (CANDY APPLE) and their subsequent use as input to the hires graphics screen (CANDY WRAPPER). The first of these programs is described in some detail since it provides the means of storing the digitized character coordinates as well as a technique for creation of special characters and symbols. The second program is included as an appendix to illustrate a particular use of the Hershey characters. A more extensive program describing their use for digital plotting is currently being documented.

Although some effort has been expended to faithfully reproduce the character fonts tabulated by Wolcott and Hilsenrath, Rh