Core Text, Chapter 6. Shaping: Ligatures and Features
You will be able to say what shaping is: a list of glyph numbers goes in, a rule book written inside the font is applied, and a list of glyph numbers comes out.
You will be able to say what shaping is: a list of glyph numbers goes in, a rule book written inside the font is applied, and a list of glyph numbers comes out.