Sets the current font face, font size and encoding.
pdf_document
The document handle, returned by cpdf_open().
font_name
The font name. Currently only the standard postscript fonts are supported.
See the ClibPDF Manual for more information, especially on how to support Asian fonts.
size
The font size
encoding
Can take the following values: MacRomanEncoding, MacExpertEncoding, WinAnsiEncoding, and NULL (the font's built-in encoding).