A customer of mine has tens of thousand of Type 1 Mac OS (7 - 9/Classic) that he wants to visualize in his app. I tried Apple Type Services as well as Core Text but neither ATSFontActivateFromFileSpecification nor CTFontManagerRegisterFontsForURL succeed installing the font temporarily to view it. Yet CTFontManagerIsSupportedFont reports them as supported.
Font Book sees and installs them, so there must be a way. My hope is that a good soul may have kept enough knowledge from that era to point me to some solution.