I'm trying to follow the process of hinting font in FontForge, described here: https://github.com/fontforge/fontforge/wiki/How-TT-Hinting-Works
Inside the 'very basic hinting' section is a list of errors that may occur, with a suggestion on how to fix each. I'm looking at point 4: 'Stems aren't aligned to pixel grid! (this problem is visible only in antialiased mode)'. Setting function 6 to always return 0 is suggsted. Problem is, I don't know what that is referring to or how to set it to always equal 0. There is literally no other reference to function 6 that I can find that provides more information.
Does anyone know what 'function 6 in FPGM' is and how to modify it?