Partcombiner documentation (Issue 4307) (issue 233110043 by address@hidden)

[PhilEHolmes]

Reviewers: Keith, Trevor Daniels,

Message:
Please review

Description:
Adds a section documenting the use of the optional argument to the
partcombiner

Please review this at https://codereview.appspot.com/233110043/

Affected files (+29, -0 lines):
  M Documentation/notation/simultaneous.itely


Index: Documentation/notation/simultaneous.itely
diff --git a/Documentation/notation/simultaneous.itely  
b/Documentation/notation/simultaneous.itely
index  
0e7b8092eaca2097a2d3a9a0e122da9cc1b493d7..1a2657c0f71313a927d0a7be8b00bfd7497b5665  
100644
--- a/Documentation/notation/simultaneous.itely
+++ b/Documentation/notation/simultaneous.itely
@@ -927,6 +927,35 @@ and second parts get marked with @qq{Solo} and  
@qq{Solo II},
 respectively.  The unison (@notation{a due}) parts are marked with the
 text @qq{a2}.

+By default, the partcombiner merges two notes of the same pitch as an
address@hidden due} note, and separates notes more than a ninth apart into
+separate voices.  This can be overridden with an optional argument of a  
pair
+of numbers after the @code{\partcombine} command: the first specifies
+the interval where notes start to be combined (the default is zero) and the
+second where the notes are split into separate voices.  Setting the second
+argument to zero means that the partcombiner splits notes with an interval  
of
+a second or more, setting it to one splits notes of a third or more, and  
so one.
+
address@hidden,verbatim]
+instrumentOne = \relative c' {
+  c4 d e f |
+  g a b c |
+  d e f g |
+}
+
+instrumentTwo = \relative c' {
+  c4 c c c |
+  c c c c |
+  c c c c |
+}
+
+<<
+  \new Staff \partcombine \instrumentOne \instrumentTwo
+  \new Staff \partcombine #'(2 . 3) \instrumentOne \instrumentTwo
+>>
address@hidden lilypond
+
+
 Both arguments to @code{\partcombine} will be interpreted as separate
 @code{Voice} contexts, so if the music is being specified in relative
 mode then @emph{both} parts must contain a @code{\relative} function,