Sets the default character font for subsequent character drawing.
Also affects symbols produced by plpoin. This routine has no
effect unless the extended character set is loaded (see plfontld).
Specifies the font:
1: Normal font (simplest and fastest)
2: Roman font
3: Italic font
4: Script font
Redacted form: plfont(font)
This function is used in examples 1,2,4,7,13,24,26.