Re: Part combiner: separate split state and voice names

[Keith OHara]

Urs Liska <ul <at> openlilylib.org> writes:

> Keith wrote:
> > I suggest looking over the existing partcombine bugs, and orchestral 
> > scores, to see what problems generally need solving.

> If there's anything I can do to help (without understanding more than 
> basic Scheme and without any option to help on the C++ part) please let 
> me know. Maybe it helps that I'm currently working on a big orchestral 
> score?

I remember that you were once trying to define \new Voices in the music
you gave to \partcombine (but it seems you decided you did not need to) : 
 http://lists.gnu.org/archive/html/lilypond-user/2014-10/msg00509.html
This doesn't work because \partcombine rearranges the music into Voices
that it defines, with names "one" "two" "shared" "solo". With the color
coding below, you can see that LilyPond's layout receives notes in four
distinct voices from \partcombine.

soprano = { d''2 f'' g'' a'' g''4 e''~e''2 R1 e''1}
alto = { b'2. c''4 c''2( e'') R1 f''4 d''~d''2 c''1}
\new Staff <<
    \context Voice = "one" { \override NoteHead #'color = #red }
    \context Voice = "two" { \override NoteHead #'color = #green }
    \context Voice = "shared" {\override NoteHead #'color = #blue }
    \context Voice = "solo" {\override NoteHead #'color = #grey }
    \partcombine \soprano \alto >>

Dan has for a long time wanted to be able to control which voices get
which notes, while still having \partcombine do the tedious work of
finding where the parts can be joined into chords, figuring rests, etc.

For example, it seems that "one" "shared" and "solo" could be reduced to one
Voice, allowing us to continue dynamics from a solo part into a2, for example,
when we force the transition with \partcombineChords.

Dan's recent question was whether two notation elements from the same 'part'
(e.g. FluteII) at the same moment, might ever need to go into to different
LilyPond Voices for purposes of layout.  The current mechanism describes, at
any moment in time, the state of the combined music: unison, chords, solo, etc.