Represents the "CharSet" entry of the font descriptor object.

It is an optional entry defined as part of the PDF 1.1 specification. It was deprecated in PDF 2.0.

It contains a string representing a PDF string object.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 122, page 283.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 120, page 342.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 124, page 285.

CharSet is a byte string formatted as a PostScript array of glyph names, such as (/A /B /C). It lists all the glyphs present in a Type 1 font subset.

Viewers can use CharSet to determine which character codes a subset font can render without decompressing and parsing the font program. It is not used for TrueType or CFF fonts.