Re: Change stem direction for voice?

[David Kastrup]

Timothy Lanfear <timothy@lanfear.me> writes:

> On 25/08/2024 17:11, Stefano Antonelli wrote:
>> On Sun, 2024-08-25 at 10:47 +0100, Timothy Lanfear wrote:
>>> \version "2.24.0"
>>>
>>> \layout {
>>>    \context Voice = "voiceTwo" {
>>>      \override Stem.direction = #UP
>>>      \override Slur.direction = #DOWN
>>>      \override Beam.positions = #'(5 . 5)
>>>    }
>>> }
>>>
>>> \new Voice = "voiceTwo" {
>>>    g'4 a' b'( c'') d''8 e'' f'' g'' r2
>>> }
>> That works just fine, but I don't want to create an explicit voice.  I
>> should have mentioned that.
>
> I think you have some misunderstandings about the way LilyPond functions.
>
> \new Voice = "voiceTwo" { ... }
>
> creates a voice and gives it an arbitrary label (voiceTwo) so it can
> be referred to later in the LilyPond code.  Labeling the voice has no
> influence on the formatting. In this case, the label happens to be the
> name of a LilyPond command, but that is of no consequence.

\new Voice = "2" { ... } on the other hand will create a voice that the
<< \\ >> construct would recycle for its second voice _if_ it is
accessible at the moment the << \\ >> is encountered.

> (Also, the label has no effect when in a layout block).

It's worthwhile to note that there is a load of difference between

\layout {
  \context {
    \Voice
    \override ...
  }
}

and

\layout {
  \context Voice {
     \override ...
  }
}

Cf this example:

\layout {
  \context Voice {
    \override Stem.color = #red
  }
  \context {
    \Voice
    \override Stem.thickness = #4
  }
}

\new StaffGroup <<
  \new TabStaff \with { \tabFullNotation } {
    c'8 8 8 8 8 8 8 8
  }
  \new Staff {
    \clef "violin_8"
    c'8 8 8 8 8 8 8 8
  }
>>

> The \\ construct automatically creates voices formatted as if
> \voiceOne, \voiceTwo etc., were present, although it seems these
> commands are not used explicitly.
>
> I can't see any method to achieve what you desire without explicitly
> creating voices and using overrides.

\\ uses make-voice-props-set and I would advise against redefining that.

-- 
David Kastrup