Function FT_IS_SCALABLE 

pub unsafe fn FT_IS_SCALABLE(face: FT_Face) -> bool

Returns true whenever a face object contains a scalable font face.

This is true for TrueType, Type 1, Type 42, CID, OpenType/CFF, and PFR font formats.

Safety

face must be a valid FT_Face that can be dereferenced.