V m Enhancements to the Language

V W enhances w by providing support for scalable fonts and thus achieving true device independence. V m turns w into a compact system (less than 10% of the size of traditional W ) , supports a printer driver definition language, supplements the T ) $ system with a number of new high-quality scalable typefaces, implements a variety of font effects (compression, shade, outline, shadow). Support of scalable fonts necessitated certain changes to the TEX program, syntax, and fonts; this article describes some of these changes. Since it is likely that other scalable implementations will follow, the author hopes that a scalable TEX standard can be defined before appearance of a conflicting set of definitions. The Aim of the V w System Device-independence. From the beginning, TFJ was designed as a deviceand resolution-independent document processor; however, because of its reliance on raster fonts, has never achieved this aim. In a typical T)$ implementation, a user is confined to particular output devices and particular resolutions by the mere necessity to maintain a large volume of raster fonts. A typical 'l&X with a reasonable collection of fonts requires between 10 and 15 MB of storage; support for a second device, or just another magnification step, adds a few megabytes of storage. The VTEX system is based on vector, rather than raster fonts. Instead of maintaining multiple copies of raster fonts at each resolution, V m keeps only one version of each font. The algorithmic encoding of characters is expanded into raster images at run time, allowing instant access to any needed magnification. Use of vector fonts not only greatly increases the number of available fonts it also shrinks the size of the 'l&X system to under a megabyte. Changes in TEX Syntax Dynamic fonts in V W necessitated certain changes in TE,X syntax, most importantly in the \font command. These changes do not interfere with the TRIP test (so V'l&X is still a m), and provide much greater flexibility in choosing fonts. scaled and at . The scaled and a t parameters work as in standard 'l&X, with an important exception: any acceptable value that follows these keywords is fully supported by all device drivers. s lant . The s lan t keyword is used to specify the amount of slant in the font. Any VT@ font can be dynamically slanted. The number that follows the keyword is the slant coefficient, multiplied by 1000. The s lan t keyword makes the existence of cmsl, cmssi and cmti fonts unnecessary, since they can be obtained from other fonts. For instance, \f ont\sl=crcirlO s lant 167 can be used to declare a slanted roman font. aspect. The aspect keyword specifies the aspect ratio of the font. aspect 1000 is the default, aspect 500 defines a half-height font, while aspect 2000 defines a font that is twice as high as the default font. The aspect keyword, in particular, makes cmdunh unnecessary, since cmdunh is fairly close to an "aspected" cmr. smallcaps. The smallcaps keyword defines a font of caps and smallcaps. Any font can be used with the smallcaps option. This keyword makes cmcsc and cmt csc unnecessary. outl ine, shadow, gray, and f i l lpa t t e rn . These keywords implement standard font effects: outline, drop shadow, gray, and pattern shading. The width of the outline and the length and direction of shadow can be specified in resolution-independent TUGboat, Volume 11 (1990), No. 3-Proceedings of the 1990 Annual Meeting 429