aalt — Access All Alternates
aalt (Access All Alternates) gathers all the alternates of a selected glyph so the user can choose among them.
It is used when the application doesn’t support the usual means of reaching an alternate, when the user needs an alternate outside the context the normal substitution assumes, or when the user doesn’t know which feature produces the desired form.
Example
Section titled “Example”.fea source
Choosing among the alternate-glyph features
Section titled “Choosing among the alternate-glyph features”Three features give access to alternate glyphs, aalt among them.
| Feature | Purpose |
|---|---|
aalt |
Gathers all the alternates of a selected glyph and lets the user choose among them |
salt |
Replaces the default glyph with an alternate chosen for the typeface’s stylistic design |
ss01–ss20 |
Replaces a meaningfully labeled set of glyphs with another, coordinated set |
salt covers stylistic alternates that don’t fit a clear category like swash or hist. ss01–ss20 don’t target individual glyphs — they switch a set of glyphs designed to harmonize with each other.
Inside an aalt feature block, a bare feature salt; statement can stand in for a substitution rule, naming another feature instead. The compiler collects every single and alternate substitution in the features named this way, grouping them by target glyph to build aalt (Adobe OpenType Feature File Specification, §8.a).
Writing it in a feature file
Section titled “Writing it in a feature file”The rules are written with Lookup Type 3.