A CIDFontType2: a CIDFont whose glyphs are TrueType glyph descriptions, selected through CIDToGIDMap.
public sealed class PdfCidFontType2 : PdfCidFont
ISO 32000-2 §9.7.4.1 and §9.7.4.2. With an embedded program, a CID selects the glyph id its CIDToGIDMap gives: the CID
itself for /Identity, else bytes 2c and 2c+1 of the map stream (high byte first). A missing map is read as
/Identity with a diagnostic. A CID past the end of the map, a glyph id the program does not have, or glyph 0 for a CID
other than 0 mean "no glyph", and the font shows the glyph of CID 0 (§9.7.6.3).
Without a usable embedded program, the CIDFont is drawn with its Substitute, whose glyph a CID selects
through the collection's Unicode values and the substitute's "cmap" (§9.7.4.2: a non-embedded TrueType CIDFont is reached through
the "cmap" table); CIDToGIDMap is ignored then.