IANAL but again, the program is not program in general sense. The regular “program” part here is ttf format and protocol around there, but protection goes over ttf data as a whole. It may be able to argue if such new font display system is developed and used, practically no gamedev/publishing industries want to reinvent the wheel and built the ecosystem from scratch.

Also, the infringement criteria is not necessarily on process but also end results similarity and intention in Japanese law. When intention comes up in argument defendant often provide proof they did not have access to the alleged source or its end product.