I'm working on coding a custom font in FontForge for some positional alternates of letters. I am not working with feature files for alternates, but using the FontForge interface for building lookups (I'm not totally opposed to a file solution, but based off what I've seen via an exported lookup to a
.fea file from FontForge, the file syntax does not seem to quite match what that link talks about, so even via file, I'm not sure how to implement this).
In that link above, it notes that when working with that type of file, one can do an "ignore" for a pattern. Assuming here that one has a medial form of a letter and an initial form, the any medial form that is preceded by another letter does not get switched to the initial form:
ignore sub @AllLetters @Medial'; sub @Medial' by @Initial;
In otherwords, there is a way to set a pattern (or patterns) to ignore doing a lookup, before the actual lookup call, to limit when the lookup is done.
However, I cannot find any documentation stating how to code that same type of
ignore statement when using the lookup dialog boxes for building lookup patterns. So in my lookup subtable for contextual chaining substitutions, I have this so far that is built (with dummy names here):
| className @<mySubstitutionLookup> |
But if I put any
ignore in, then it states that "ignore is not a class name for the matching classes" (which I understand why it is saying that, since I have not defined an "ignore" class, but neither should I need to if it were a keyword).
So apparently, in the lookup dialog...
ignore statements need to be coded differently, but again, I cannot find documentation of how (or even if, though I would think they could) those dialog boxes can code that.
So how does one get an
ignore statement to code into a contextual chaining substitution using the program's dialog boxes? And if a FontForge
.fea file can do it, how exactly is that done with the variation of syntax?