Re: An issue with kerning in a defined dynamic "sfffz" solved

[Werner LEMBERG]

> Some time ago I wrote saying that I could not get the marking
> "sfffz" to kern properly.  Someone replied that it did for them, and
> I let it sit there, waiting until I needed a solution, which point I
> have now reached.  I have been slow and dense in recognising where
> the issue lies - I am using the BMusicFont (a version of Dorico's
> font, more recent than the "profondo" version).  The kerning works
> in Feta, but not in this font.

By the way, there was a bug in the script that generates the
Emmentaler font (now fixed, see
https://gitlab.com/lilypond/lilypond/-/merge_requests/1353); depending
on the used FontForge version it was possible that there was no
kerning at all for Feta dynamics and numbers.

> I have, however, managed an effective work-around:
> 
>       sfffzX = \markup\center-align\concat{"s" \dynamic"fff" \hspace #-0.5 
> "z"}
>       sfffz = #(make-dynamic-script sfffzX)
> 
> The "s" already kerns ok, and specifying the "fff" dynamic gets the
> fully-kerned version of those letters.  The "z" doesn't kern nicely,
> but can be pushed back to the required position.

Glad that you found a workable solution.  Note, however, that the
kerning problem with 'BMusicFont' is not a LilyPond problem – it
simply passes a string of glyphs to the rendering engine (Pango),
which takes care of applying OpenType features like 'kern'.  Attached
you can see the difference between kerning on and off while using the
Emmentaler font.

```
sfffz = #(make-dynamic-script "sfffz")
sfffzMarkup = \markup {
                \override #'(font-features . ("-kern"))
                  \dynamic "sfffz" }
sfffzX = #(make-dynamic-script sfffzMarkup)

{ c''2^"with kern" \sfffz }

{ c''2^"without kern" \sfffzX }
```

Maybe there are similar OpenType features present in 'BMusicFont'?
For example, I could imagine that you have to deactivate the 'liga'
feature so that the combination 'f' + 'f' doesn't get converted to
glyph 'ff', which seems to have different kerning (or a lack thereof).


    Werner