THPDFTrueTypeData.UnicodeGIDForCodepoint
function UnicodeGIDForCodepoint(Cp: Cardinal): Integer;
Looks up a Unicode scalar using strictly validated Unicode format 4 and format 12 subtables, including supplementary-plane code points
Returns zero for a missing glyph, an invalid scalar, an unpaired surrogate value, or absent supported Unicode tables
The method never interprets a Unicode scalar as a MacRoman byte or falls back to a Symbol private-use mapping; existing GIDForCodepoint retains its original decoder behavior