Represents the PDF Character Set.
Values:
| IG_PDF_CHARSET_UNKNOWN | 0 | The font does not use Adobe Standard Encoding. |
| IG_PDF_CHARSET_ROMAN | 1 | The font uses Adobe Standard encoding. This is determined by the "Uses Adobe Standard Encoding" bit in the font descriptor. |
| IG_PDF_CHARSET_EXPERT | 2 | Currently unused. |
| IG_PDF_CHARSET_LAST | 3 | Placeholder for the last value of this enumeration. |