SWI-Prolog includes a native GUI library -- XPCE. It makes use of a few system fonts. As detailed in the Specifying fonts section of its User Guide, it can be configured to make use of additional system fonts. The example given shows how to do this configuration under unix and makes use of a parameter string obtained from the xfontsel utility to name the new system font.
How do I determine this parameter string for use in SWI-Prolog running under Microsoft Windows?