Font

In computing, a font refers to a typeface that has a distinc-tive appearance and style. In most word processing, desk-top publishing, and other programs the user can select the point size at which the font is to be displayed and printed (in traditional typography each point size would be consid-ered to be a separate font). Operating systems such as Windows and Macintosh usually come with an assortment of fonts, and applications can register additional fonts to make them available to the system.

Fonts are often presented as a “family” that includes the same type design with different attributes such as bold-face and italic. The spacing of letters could be uniform (monospace) as in the Courier font often used for printing computer program code or proportional (as with most text fonts). For proportional fonts the design can include kern-ing, or the precise fitting together of adjacent letters for a more attractive appearance. Fonts are also described as serif if they have small crossbars on the ends of letters such as at the end of the crossbar on a T in the Times Roman font. Other fonts such as Arial lack the tiny bars and are called sans serif (without serif).

There are two basic ways to store font data in the computer system. Bitmapped fonts store the actual pat-tern of tiny dots that make up the letters in the font. This has the advantage of allowing each letter in each point size to be precisely designed. The primary disadvantage is the amount of memory and system resources required to store a font in many point sizes. In practice, this con-sideration results in only a relatively few fonts and sizes being available.

The alternative, an outline or vector font uses a “page description language” such as Adobe PostScript or Tru-eType to provide graphics commands that specify the draw-ing of each letter in a font. When the user specifies a font, the text is rendered by processing the graphics commands in an interpreter. Since the actual bitmap doesn’t need to be stored and all point sizes of a font can be generated from one description, outline fonts save memory and disk space (although they require additional processor resources for rendering). While sophisticated scaling techniques are used to maintain a pleasing appearance as the font size changes, outline fonts will not look as polished as bitmapped fonts that are hand-designed at each point size. (For use of fonts see typography, computerized.)