User cbm80amiga has uploaded a nice library to render 7-segment numbers on graphical displays – especially for Arduinos. But the code can as well be used without any Arduino in the proximity, just a slight change in the library made it an universal C++ object.
It had the ambition to follow up with further details, but never made it. So here is the quick-and-dirty code example: http://sciencetronics.com/download/20200722_m328_oled_cpp.zip
Here it runs on an ATmega328 and an OLED-display (with SSD1306 controller):
