Apple Technologies

AAT was asked first to open all the text in the text layout in the form before they occur. Operating in full text on the shape layer.Table used in the core of the design process of AAT is "morx" table. The "morx"table is divided into a series of strings, each string is divided into sub-tables.Processing chain and order sub-table. When each sub-engine layout table foundmore signs in the child table of the control flag, usually from the user settings. This determines whether the sub instruction.Set of features available in the source is accessible by the user through the "feat" table. "Magnificent feat" table provides a localized string pointer, can be used to describe a functional, end-user and the corresponding flag to send the text engine, if you select the function. Intangible characteristics, the user can projectthrough the simple expedient of not including in the "achievement" as the table.Apple uses this method, for example, support the need for ligatures.

Child table can not contextual substitution of glyphs, replacing the context of howthe reordering form and ligation in the form of training  related to the contents are sensitive to the actions of the text. Can be used, for example, automatically become a ss in any word, apart from its end.
The "morx" non-contextual glyph substitution subtable is a table of simple mapping between form and alternatives to it. In all the other involving the use offinite state machine.