Feature circled characters

Jani Paavola

What's your preferred way to make circled characters accessible as OpenType feature? dlig? salt? stylistic set?

Peter Baker

The OpenType feature nalt is there for this purpose. I use it with rlig to make two-digit circled numbers.

André G. Isaak

I would go with a stylistic set for the simple reason that stylistic sets can be assigned keyboard shortcuts in InDesign whereas things like salt and nalt cannot (as far as I know — I wasn't even aware of nalt until now).

Thomas Phinney

Peter, the 'nalt' feature is not so specific, though. From the feature registry, it: “Replaces default glyphs with various notational forms (e.g. glyphs placed in open or solid circles, squares, parentheses, diamonds or rounded boxes). In some cases an annotation form may already be present, but the user may want a different one.”

So while it *can* be used for that, it does not mean *only* that. Rather like 'salt' in that regard.

John Hudson

‘nalt’ was primarily registered for the context of East Asian typography, in which a variety of notational forms exist. I wonder how widely supported it is in software, especially outside of CJK-specific layout?

Jani Paavola

Proceeding with the stylistic set solution. Thank you all!

Peter Baker

I should have said that this was one of nalt's purposes. I used nalt partly because I was running short of Stylistic Sets, which are of course more convenient than almost anything else. As for software support, MS Word is hopeless, but you can use nalt and almost any other OpenType feature with TeX, LibreOffice, InDesign (with Roland Dreger's terrific open-type-features script), or Affinity Publisher.

Johannes Neumeier

While the questions was about what the most suitable feature for use case is, there is no (technical) reason not to include the same transformations in several features.

Define a lookup for the substitutions, reference the lookup in any number of features, just be mindful of the lookup order in your feature file with regards to other features/lookups. 

Including, for example, multiple stylistic sets’ lookups in the general stylistic alternates feature is fairly neat, as long as the individual stylistic sets don't contradict each other. You get a "all alternates on" switch. Of course you may opt to retain the stylistic alternates feature for unique alternates not referenced elsewhere, but both approaches are valid.