This section contains various functions used to perform so-called ‘incremental’ glyph loading. This is a mode where all glyphs loaded from a given FT_Face are provided by the client application,
Apart from that, all other tables are loaded normally from the font file. This mode is useful when FreeType is used within another engine, e.g., a PostScript Imaging Processor.
To enable this mode, you must use FT_Open_Face, passing an FT_Parameter with the FT_PARAM_TAG_INCREMENTAL tag and an FT_Incremental_Interface value. See the comments for FT_Incremental_InterfaceRec for an example.