Re: partCombine and direction of stems

[Malte Meyn]

Am 04.04.19 um 10:23 schrieb Gianmaria Lari:
> I don't understand how lilypond manages the stem direction in the 
> following code. Why the difference in the two scores?

\partCombine is for combining a first and a second (or upper and lower) 
part in a score, like flute 1 & flute 2 or soprano & alto. As long as 
the first/upper part has the higher notes, LilyPond will print simple 
chords. When the parts cross (first/upper part has the lower notes), 
this will be shown as two different voices so that the stem directions 
show the non-standard order of voices.

If you want two separate voices in both cases, you can use 
\partCombineApart or instead of \partCombine just << \\ >>.

If you want chords in both cases, you can use \partCombineChords or 
instead of \partCombine just << >> without \\.

%%%%%%%%%%%%%%%%%
\version "2.21.0"

upper = { c' d' e' f' }
lower = { a b c' d' }

\partCombine \upper \lower
\partCombine \lower \upper
\partCombine { \partCombineApart \upper } \lower
\partCombine { \partCombineChords \lower } \upper
<< \upper \\ \lower >>
\new Voice << \upper \lower >>
%%%%%%%%%%%%%%%%%

N.B. If someone wants to try this at home be aware that in 2.19.83 and 
earlier versions it has to be \partcombine, \partcombineApart, 
\partcombineChords (with lowercase c in “combine”).