So… First, a bit of context in case it helps:
I did my first script (roman cursive) font. Although I did not know about the "four positional OT features (init, media, fina, iso), I intuitively created my own positional classes with alternate glyphs and paired them using a bunch of contextual alternate substitutions. So every letter has three basic forms. For example: e (which goes in the @MID class); e.end (goes in @END class); and e.start (goes in @STRT class).
So, my core substitutions go like this:
sub @MID by @END;
sub @END '@MID by @MID;
sub @END ‘@END by @MID;
sub @END’ @STRT by @MID;
I should mention I do have a lot more subs to handle specific pairs and contexts; and everything runs smoothly and as expected.
The issue I’m encountering is when it comes to rendering the font in certain places
For example, this is how It looks on Glyphs. Everything’s fine, and it also looks fine in Illustrator as well.
This is a close up look on the connection ‘i’ - ‘n’
However, when uploading the font to Fontspring, I noticed this:
(On a side note: their preview rendering has contextual alternates OFF by default, so that’s why the “h” looks different from the screenshot above)
I had a hard time trying to understand why this happens, until I saw that this issue is also showing in the Hinting preview:
For some reason, the connection issue is not so dramatic on some pairs, but it is extreme in others.
You can see several issues here. But they don’t show on my normal preview.
Here’s the same word on my website’s type tester (Fontdue)
As you can see, it looks pretty good, but I’m afraid there must be an issue I am not fully aware of. I tried to submit this font to Monotype and they rejected it twice. Maybe their automated system is also noticing something I’m not? Is it an issue that my strokes are live strokes and not expanded outlines? The issue persists even when expanded whatsoever.
I wonder what could be causing this render issue.
My Glyphs version is cutting edge: 3.3 (3303)
EDIT: So after proofreading this post, I noticed that the hinting windows does not display kerning data (as in T - h). Maybe that’s what causing the issue in the hinting preview? But what about Fontspring’s preview?