I have added kerning classes for Greek, and pair adjustment values in the kerning table. However, the Preview Toolbar and Glyph Edit Window do not show the pairs as kerned.
If I test the font, then use the test font in PagePlus, the kerning works as expected. Why does FontCreator not show kerning for Greek? Does it work for Cyrillic?
Kerning Enabled in PagePlus
Preview Toolbar in FontCreator
Maybe it is related to the bug you reported earlier.
Can you please send the font project file along with some sample text?
The Font Project is attached to the bug report thread.
This is the sample text that I used in the preview toolbar.
ΑΤΔΥΛΨ ATAYAT
I’m not sure why a web browser would use Latin script for Greek kerning, as Greek kerning should be added to the Greek script.
I’ve done some testing, and as mentioned in this topic OpenType Layout Engines work slightly different 
I’ll add these findings there as well.
Firefox uses Latin as fallback script in case the correct script is not available.
Microsoft Word (on windows at least) uses a similar approach, but will also use other scripts in case the correct script is missing.
Maybe FontCreator should support this too, but then also make clear it isn’t by the rules…
I was going to ask about how this ought to be implemented, but then no one follows the rules.
Most of my fonts only contain Basic Greek, which is not for Greek text but for Maths and similar uses in English text.
Perhaps fonts with a full Greek Extended character set should have a Greek script and a separate kerning table for Greek. It’s all a bit much to be honest. I prefer to have no more scripts and languages than really necessary as it makes fonts harder to maintain.
I think FontCreator should kern Greek with Latin kerning tables if adjustment pairs are included in the kerning table for the Latin script.
It seems Sitka is one of a few Windows fonts that has correctly (at least the way we think it should be) defined the OpenType layout features. It contains different pair positioning lookups for each script, but all have a mutual pair positioning lookup for digits:
Most other fonts that include both Latin and Greek characters, just put them all in one huge pair adjustment lookup which is added to both Latin and Greek script.
I can get it to work for Greek or Latin, but not both. How does Sitka manage that?
You have the Preview Toolbar set to Auto, and so do I, but the Greek text only kerns if I select the Greek script which automatically selects the ELL language.
It should work, so please send me the updated project file.
Here it is:
The plot thickens. If I select the Latin Script, the kerning is applied twice to the Greek Text.
If I delete the Greek kerning feature from the Latin script, and just leave it in the Greek script, selecting Auto still does nothing, but selecting Latin kerns both Greek and Latin text.
Balava Regular.fcp (483 KB)
I see. You added Greek script (grek) with Greek language (ELL).
With your current implementation, even in Firefox you need to provide the corresponding language (el) to make it work:
All fonts I’ve seen only use the default language, which does work with the Auto script/language option in FontCreator too. So I suggest you change the language tag from ELL to DFLT.
Thanks. That does work. If it’s the only method that works, I may have to do it that way.
If I add the KerningGreek feature to the Latin Script, the Greek text is kerned twice as it is in your screen shot.
However, if I delete the adjustment pairs for Greek from the Latin Kerning table, the Preview text is kerned correctly when the script is set to Latin. Testing in Vivaldi and Firefox, only the Latin text is kerned.
This is too complex for my brain at the moment, it is time for a nap.
I’m not sure if it is the only or best way, but I think it comes closest to what was meant when the OpenType layout feature specs were defined.
It isn’t applied twice here; I deliberately changed the kern value so I can more easily see work.
If a page contains content in another language than the default language, you need to explicitly add a language attribute to an element surrounding that content.
The Web Test Page as provided by FontCreator only has one such language attribute for the whole preview text.
I found that PagePlus was not kerning the Greek text (not even with the language set to Greek) with the kerning table in the Greek Script, so I added it to the Latin Script too. That works and is not hard to maintain. By moving the kern features to the top they are accessible without any scrolling or collapsing/expanding of the feature trees.
I’m glad to know you found a way that works, but now we are totally lost about what is the best approach for adding non-Latin kerning 
Does this imply that if a font is intended for everyday use in the Greek language then it needs the ‘Greek Extended’ unicode block fully populated ?
Are there any Greek people on this forum ?
I think Greek Extended is only needed for Ancient Greek.
Only for Modern monotonic Greek the Greek Extended block isn’t necessary. For all other purposes (ancient Greek, katharevousa, polytonic Greek) you can’t do without Greek Extended.
Is Polytonic Greek used much these days?
I thought it was deprecated when they simplified the language in 1982.
What I need to know is how useful it would be to people to populate the Greek Extended unicode block ($1F00 to $1FFF).
As a wild guess, I would say it essential for those scholars who need to write in ancient Greek, but useless to 99.99% of Greeks.
The reason that my font Garava includes it is because I used that to test the Complete Composites feature. Guru and Acariya, which are basically the same font but with different widths, also include it. My other fonts do not.
With Transform scripts and Complete Composites it’s not hard to add, but it still takes time to check the spacing of this large character set, which could be better spent on other things.
Arial and Times New Roman include it, but Georgia and Verdana do not.