See https://forums.garmin.com/showthread.php?220360-Font-conversion-tool-for-Mac for some options.
Now if I can just figure out how to force it to create a 1 bit image because it just wants to create color images.
The resource compiler should do the right thing and reduce the data down as far as possible.
Thanks for that. I couldn't get BMFont working under the new version of Wine (supporting 64 bits) as it won't build (XCode complains about 16bit support). I got BMGlyph but although the resource loaded the font was invisible. Setting the font color to white and background to black (no transparency) fixes the issue. Thanks again.