FrameSetFontName

Help Contents GUI programming Frames FrameSetFontName
FrameSetFontSize FrameSetFontStyle

FrameSetFontName aframe size

Command to set the font name of the Frame aframe to name, which must be a valid font name.

Example: 

f=Frame [][MyFrame] wxdefault_frame_style [100 200][200 100]
FrameSetFontName f [Courier]
b=(Button f [Close][ern "f  GC] 0 [-1 -1][200 70])

Reference:

FrameSetFontSize FrameSetFontStyle