Gets the glyph name the font's encoding gives a character code; .notdef when it gives none.
public string GetGlyphName(byte code)
The character code.
ISO 32000-2 §9.6.5. The built-in encoding is the Symbol or ZapfDingbats encoding for those two Standard 14 fonts (Annex D.5,
D.6) and StandardEncoding for the other twelve and for any other font that is not embedded (Annex D.2); a predefined encoding
named on a non-embedded Symbol or ZapfDingbats font is ignored, as pdf.js does. For a Type 3 font the encoding is entirely
defined by the Encoding entry (§9.6.5.3).