In my set of custom font tools there is a folder utility that generates png thumbnails for custom fonts. The code, although in python, may contain something you can use in scheme. Link here:
Custom Font Tools Release 12It currently generates an image according to the rules:
'Ab' image when detecting upper-case and lower-case characters.
'AB' image when detecting only upper-case characters.
Examples below:
- Bolonewt_Fizzy_Orange.png (137.18 KiB) Viewed 2154 times
- Bolonewt_Style_Whorl.png (129.84 KiB) Viewed 2154 times