I have a question about variation sequence support in Glyphs 2.6.1.
Glyph MJ030274, which is encoded as a CJK compatibility ideograph at U+FA4C, can also be represented by variation sequences <U+793E,U+FE00> (SVS) and <U+793E,U+E0103> (IVS).
Is there a way to support both variation sequences without duplicating the glyph?
First off, I looked at Glyphs export output and I see the cmap format 14 table is being created. Having this capability at all is a great step forward for me. Thank you so much for your work!
To answer your question, this issue technically affects all characters with defined Unicode variation sequences. “Default” and “non-default” UVSes are specified in different tables. It seems that Glyphs only handles non-default UVSes.
The case I mentioned above represents one of the ~91 Japan-source CJK compatibility ideographs. These cases are the most problematic examples, because they have three Unicode representations for the same glyph:
the code point for the compatibility ideograph
the code point for the corresponding unified ideograph plus a [standard] variation selector (for the NFC form of the compatibility character)
the code point for the corresponding unified ideograph plus an ideographic variation selector (for the ideographic variation sequence, as defined by the Adobe Japan or Moji Joho collection)
Here’s some TTX cmap data for comparison. (For clarity, I deleted the format 4 Microsoft-platform subtable data.) Glyphs only maps the “default” UVSes (corresponding to their base character’s default glyph) when I duplicate the glyph: once for uni793E and twice for uniFA4C.