Closed m4rc1e closed 6 years ago
what are these "combos which shaping engines allow"?
@anthrotype I assumed that shaping engines could only add Nonspacing marks to certain base glyphs... I'm wrong.
Interestingly in Mac OS X, it will position glyphs which are not Nonspacing Marks as well.
D positioned with acute (U+00B4)
Font with no anchor on acute (U+00B4)
check that font's GDEF table, and see if the "acute" glyph is marked as class 3 (combining mark)
Ok it’s not marked as such, but still it is included in the Coverage table of the mark class for all the top marks, along with acutcomb etc so for the sake of the mark feature it is a combining mark
The GDEF category applies for things like IgnoreMarks lookup flags
Since each font builder has their own way of building GPOS mark features, I'm tempted to only diff combos which shaping engines allow.