Manipulating Font Features

ATSUI provides the following functions for manipulating font features in a style object:

ATSUSetFontFeatures sets font features in a style object.
ATSUGetFontFeature obtains the font feature type and selector for an indexed font feature.
ATSUGetAllFontFeatures obtains font feature information from a style object.
ATSUClearFontFeatures removes previously set font features from a style object.