SMuFL Advance Width in Dorico

[sugarfree]

What is the purpose of so many Advance Width entries in SMuFl fonts .json files (other than Bravura)? Doesn’t Dorico use the BBboxes and anchors for most of the non-textual symbols? E.g. why would “noteheadBlack“ need advance width, if it has zero-bearings and stemUP/Down anchors? I notice that most of the glyphs simply duplicate their metric width as advance width.
(I tried asking at Dorico forum, but didn’t get an answer)

[tisimst]

I’m digging from my memory, but I believe Dorico mostly only uses the glyph’s bounding boxes directly from the font and not even from the json file. When Daniel Spreadbury was coming up with SMuFL, he was envisioning how programs *might* access the data and therefore provided a few different options even though that’s not how Dorico does it. I do not know how MuseScore or other SMuFL-compliant apps use the json data (if at all). That being said, when I was creating fonts, I made it a point to make the json file data meaningful and as complete as I could.

[sugarfree]

I’m working on a new SMuFL font, and I’m just evaluating if it’s worth the effort to develop a script for Glyphs3, just to populate redundant information, which doesn’t have a semantic meaning if it just repeats the bounding box metrics. I see this is how it’s done in MTF fonts, and I wonder if there’s a reason for this that I don’t see. As far as I understand the SMuFL definition of Advance Width, it’s the bounding box + positive side-bearings; to provide an additional width metric for in-line applications, when it’s different than the bounding box itself. IOW, Advance Width can only matter when a glyph has positive side-bearings.

[tisimst]

If you’re using Glyphs, then you might be interested in the scripts already created for it, found on GitHub. I never used Glyphs when I did my MTF work, so I can’t vouch for them, but they might be enough to get you what you need.

https://www.github.com/steinbergmedia/smufl

[sugarfree]

yes, I use them. They are outdated, using a deprecated Python syntax. Luckily, chatGPT had no problem rewriting them for Glyphs3. In any case, the scripts only support engraving defaults, bounding boxes and anchors.

[Magister Tekton]

Using FontForge to create the revised font?

[sugarfree]

I use Glyphs3. This will be a new font based on plate engraved sheet music.