CFF - PostScript font program
(Compact Font Format) table (OpenType 1.8)
This table contains a compact representation of a PostScript Type 1, or CIDFont and is structured according to Adobe Technical Note #5176: “The Compact Font Format Specification,” and Adobe Technical Note #5177: “Type 2 Charstring Format.”
Existing TrueType fonts use a glyph index to specify and access glyphs within a font, e.g. to index the loca table and thereby access glyph data in the glyf table. This concept is retained in OpenType™ PostScript fonts except that glyph data is accessed through the CharStrings INDEX of the CFF table. The Name INDEX in the CFF must contain only one entry; that is, there must be only one font in the CFF FontSet. The CFF Top DICT must specify a CharstringType value of 2. The numGlyphs field in the 'maxp' table must be the same as the number of entries in the CFF’s CharStrings INDEX. An OFF glyph index is the same as the CFF glyph index for all glyphs in the font.