The composite font technology is a general solution that extends the basic PostScript language font mechanism to enable the encoding of very large character sets and handle non-horizontal writing modes.
A Type 1 PostScript font has room for encoding only 256 distinct characters. A typical Japanese font has over 7,000 Kanji, katakana and hiragana characters. The composite font technology allows you to create one ``composite'' font that is made up from any number of ``base'' fonts. In addition, the composite font technology allows you to include two sets of metrics (character spacing details) in the font: one for a horizontal-writing mode, and one for a vertical-writing mode.