Kern On

These three letters have the same spacing and, for spacing purposes, the same shape on the right side. However, kern-on insists on giving 'a' a significantly tighter kerning when combined with other characters. If I try to adjust it, kern-on starts saying it's conflicting other pairs and forcing me to set is as independent. Is this something deliberate or am I doing something wrong?

This is strange. Maybe the right side of the a has special spacing (or, n and u have special spacing)?

You can also send me the file if you don’t mind, then I can have a quick look myself.

Thanks for your response, Tim. Please, let me know what's your preferred way to send you the file.

You can send it to me by e-mail (see the footer on https://kern-on.com/). Thanks!

Thank you for sending the file.

There seems to be a bug in the latest cutting-edge Glyphs version (3316). With Glyphs 3260 (the current stable version) and with Glyphs 3300 (this is just a somewhat older version I have) I am getting the expected, consistent Kern On behaviour in a, n and u.

Also, if I decompose the cap components used for the serifs, I am getting the expected, consistent Kern On behaviour.

In other words, there seems to be a recently introduced bug in Glyphs. Kern On calls GSLayer.copyDecomposedLayer and GSLayer.flattenOutlinesRemoveOverlap. Apparently this does not correctly decompose caps in Glyphs 3316.

Maybe Georg can shed more light on this.

Thanks for taking the time to look into this!

Good news! The bug in Glyphs has been fixed. If you update to the latest cutting-edge Glyphs version (or use the latest stable version) things should work as expected.