How to adjust the vertical placement of markups in Lilypond

Question

Using Lilypond 2.20 on Ubuntu 20.04.

This code:

...
%% fingering symbols
fngaLong = \finger\markup{\box{\pad-markup #0.2 \override #'(font-name . "pipa") \fontsize #7 "a-"}}
...
\appoggiatura{c8-3} a2-1\trill\fngaLong
...

renders like this:

But I must place the trill under the boxed fingering symbol. In another word, I must swap the vertical position of the trill symbol and the boxed fingering symbol. How to do this?

Another question: The finger number 3 is smaller than the finger number 1. I'd like to make the 3 as big as the 1. How to do this?

Many thanks in advance!

Answer 1

The order in which several things are stacked vertically is controlled by the outside-staff-priority. The lower the priority, the closer to the staff. You can find all the info in the in the corresponding section of the docs.

As for the fingering, the easiest way would probably be using a tweak (at least if you want to do this in one place only). Instead of something like c8-3, you would write c8-\tweak font-size #2 -3. If you would like to do this globally for all the grace notes, then, sadly, I don't know how to do that. Maybe you could manipulate the Grace_engraver in your \layout block somehow, but I don't know what to do.

Answer 2

I read the answer from @Ramillies, the document is comprehensive but I did not figure out how to use the commands correctly. Then I found a very simple example in the doc page Expressive marks attached to notes.

Now this vertical stack of markups is exactly what I want:

My source code:

...
%% fingering symbols
fngaLong = \finger\markup{\box{\pad-markup #0.2 \override #'(font-name . "pipa") \fontsize #7 "a-"}}
...
\once \override TrillSpanner.script-priority = #-300
\appoggiatura{c8-3\startTrillSpan^\fngaLong} a2-1
c8\stopTrillSpan d4\fermata c8