Fingerings for 2 voices on the same staff in the same direction in LilyPond

Question

I am having a hard time finding a way to get the fingering markings for two voices in the left hand, onto the same side of a single staff in LilyPond, like in the picture below:

My aim is: to get fingerings for both voices on the same side of the staff (above or below).

The voices should be independent like this:

lower = {
  \new Voice = "lower" <<
     \new Voice { \voiceOne \alt }
     \new Voice { \voiceTwo \tenor }
  >>
}

NOT put into chords like this:

lower = {
  \new Voice = "lower" <<
  { \alt }
  { \tenor }
  >>
}

If I use the default way of adding fingering to single notes in each voice like c4-4, then their preferred fingering direction is that one goes above the staff and one below.

If I try to force them in the same direction by always using ^ like c4^4, then the layout algorithm doesn't respect that there are 2 voices in the staff, and both fingerings go in the exact same position – i.e. they get overlaid over each other and aren't readable anymore.
(The same thing happens if you try with the \override Fingering.direction = #UP option)

Another idea I had was to separate the fingerings into a 3rd voice context like this:

fingeringMII = { s4-4 }
\new Staff \context Voice = ManII { \lower }
\context Voice = ManII { \fingeringMII }

This is basically working well, but the notation I need c4-5-4 doesn't work with invisible rests. The notation c4-5-4 results in a fingering of 4 above 5 as expected. However s4-5-4 behaves differently – and displays as 54. I tried to circumvent this with chords like this <s-5 s-4>4, but this gives an error, as the chord construct seems to not allow for rests.

So the only way I have found to get what I like, is to add fingerings for both voices to the upper voice like this c4^5^4, but this is not the best to maintain.

What is a better solution?

Answer 1

Depending on the range of the tenor line, you might be able to get away with just overriding the fingering staff padding for the tenor voice:

alto = {
    \new Voice {
        \voiceOne       
            b4_3 cs'_2 d'_1 a_3 |
    }
}   

tenor = {
    \new Voice {
        \voiceTwo
        \override Voice.Fingering.staff-padding = #3  %%%
            g4-5 g-5 a-3 fis-5 |
    }
}

However, if there are lots of low notes for these voices, this isn't going to be a good method.
But, if there are just a few notes that are too low in the staff, you can tweak them manually.