8.3.1 Automatic part combining

Automatic part combining is used to merge two parts of music onto a staff. It is aimed at typesetting orchestral scores. When the two parts are identical for a period of time, only one is shown. In places where the two parts differ, they are typeset as separate voices, and stem directions are set automatically. Also, solo and a due parts are identified and can be marked.

The syntax for part combining is

\partcombine musicexpr1 musicexpr2

The following example demonstrates the basic functionality of the part combiner: putting parts on one staff, and setting stem directions and polyphony

     
     \new Staff \partcombine
       \relative g' { g g a( b) c c r r }
       \relative g' { g g r4 r e e g g }

The first g appears only once, although it was specified twice (once in each part). Stem, slur, and tie directions are set automatically, depending whether there is a solo or unisono. The first part (with context called one) always gets up stems, and ‘Solo’, while the second (called two) always gets down stems and ‘Solo II’.

If you just want the merging parts, and not the textual markings, you may set the property printPartCombineTexts to false

     
     \new Staff <<
       \set Staff.printPartCombineTexts = ##f
       \partcombine
         \relative g' { g a( b) r }
         \relative g' { g r4 r f }
     >>

To change the text that is printed for solos or merging, you may set the soloText, soloIIText, and aDueText properties.

     
     \new Staff <<
       \set Score.soloText = #"ichi"
       \set Score.soloIIText = #"ni"
       \set Score.aDueText = #"tachi"
       \partcombine
         \relative g' { g4 g a( b) r }
         \relative g' { g4 g r r f }
     >>

Both arguments to \partcombine will be interpreted as Voice contexts. If using relative octaves, \relative should be specified for both music expressions, i.e.,

\partcombine
  \relative ... musicexpr1
  \relative ... musicexpr2

A \relative section that is outside of \partcombine has no effect on the pitches of musicexpr1 and musicexpr2.

See also

Program reference: PartCombineMusic.

Bugs

When printPartCombineTexts is set, when the two voices play the same notes on and off, the part combiner may typeset a2 more than once in a measure.

\partcombine cannot be inside \times.

\partcombine cannot be inside \relative.

Internally, the \partcombine interprets both arguments as Voices named one and two, and then decides when the parts can be combined. Consequently, if the arguments switch to differently named Voice contexts, the events in those will be ignored.