The CTRun opaque type represents a glyph run, which is a set of consecutive glyphs sharing the same attributes and direction.
- Core Text
The typesetter creates glyph runs as it produces lines from character strings, attributes, and font objects. That is, a line is constructed of one or more glyphs runs. Glyph runs can draw themselves into a graphic context, if desired, although most users have no need to interact directly with glyph runs.