no kerning group?

[synthview]

Hello,
I am looking at the kernings generated by Kern-On and spotted this:
Thorn;Y;-140
Thorn;Yacute;-140
Thorn;Ymacron;-140

Shouldn't we expect a group here?

[Tim Ahrens]

Class kerning (groups, as Glyphs calls it) is not necessarily better in this case:

• Three glyph-glyph pairs cost 3 * 4 bytes plus overhead for the first glyph.
• Writing these pairs into the class kerning table will add a row to the table, which costs 2 bytes per cell plus class definition overhead.

Writing a sparse row is inefficient. In this case, using glyph-glyph pairs is more efficient unless the subtable row is very short.

[synthview]

wow smart! ok thanks :)