Type Alias Kerning 

pub type Kerning = BTreeMap<Name, BTreeMap<Name, f64>>;

A map of kerning pairs.

This is represented as a map of first half of a kerning pair (glyph name or group name) to the second half of a pair (glyph name or group name), which maps to the kerning value (high-level view: (first, second) => value).

We use a BTreeMap because we need sorting for serialization.

Aliased Type

pub struct Kerning { /* private fields */ }