How postscript name work

[Moi15 Moi]

Hi,

I am trying to understand how Freetype take the postname in the naming table for opentype and truetype font to be able to reproduce it with fonttools

From what I can see, all the detail are here: https://github.com/freetype/freetype/blob/c26f0d0d7e1b24863193ab2808f67798456dfc9c/src/sfnt/sfdriver.c#L1044-L1087

My problem is that I don't understand: https://github.com/freetype/freetype/blob/c26f0d0d7e1b24863193ab2808f67798456dfc9c/src/sfnt/sfdriver.c#L1054-L1062

In particular, what is 

• TT_CONFIG_OPTION_GX_VAR_SUPPORT: https://github.com/freetype/freetype/blob/c26f0d0d7e1b24863193ab2808f67798456dfc9c/devel/ftoption.h#L737
• FT_IS_NAMED_INSTANCE: https://github.com/freetype/freetype/blob/c26f0d0d7e1b24863193ab2808f67798456dfc9c/include/freetype/freetype.h#L1443-L1444
  
• FT_IS_VARIATION: https://github.com/freetype/freetype/blob/c26f0d0d7e1b24863193ab2808f67798456dfc9c/include/freetype/freetype.h#L1461-L1462

Have a nice day