User Guide

Making OpenType Fonts
667
Alternate Substitution
Alternate substitution replaces a glyph with one of the glyphs in a pre-
defined list of alternatives. The application that uses the font is expected to
decide which glyph to choose. A good example of this lookup is to provide
several versions of some glyph, like the ampersand. Another application is
the selection of several different forms of ornaments.
An alternate substitution rule is specified as:
substitute <glyph> from <glyphclass>;
For example:
substitute ampersand from [ampersand.1 ampersand.2];
or ornament variations:
substitute asterisk from [orn.1 orn.2 orn.3 orn.4];