Represents the "FontDescriptor" entry of the truetype font dictionary object.

It is defined as part of the PDF 1.0 specification.

It contains a FontDescriptorElement.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; page 257.

The FontDescriptor provides the font metrics and holds the embedded TrueType font program in a FontFile2 stream.

TrueType fonts used for non-symbolic encodings must have a FontDescriptor. For symbolic fonts it is also recommended so that the font can be embedded and metrics are reliably available.