[PATCH] autochange.scm: Use averaged chord pitches to determine staff.

[Mark Polesky]

In NR 2.2.1 Changing staff automatically, it says this:

Chords will not be split across the staves; they will be assigned
to a staff based on the first note named in the chord construct.

http://kainhofer.com/~lilypond/Documentation/user/lilypond/Common-notation-for-keyboards.html#Changing-staff-automatically


Actually, this is not true; they are assigned to a staff based on
the *last* note named in the chord construct. The reason is that
in scm/autochange.scm, the NOTES variable referenced on line 17
ultimately comes from a *reversed* context-list (see line 38).

Anyway, I think that it would make a lot more sense if the staff
were determined by the "average" pitch of the chord. And, I think
I've solved this in the attached patch. 

I've also attached 2 png's to demonstrate the difference: the
first one (current.png) was compiled with the current
autochange.scm and the second one (revised.png) was compiled with
my revised patch. You can look at the test file below to see how
it is set up.


Would anyone like to comment?
Are there any objections to me applying it?

Thanks.
- Mark

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\version "2.13.2"

uppersFirst = \relative {
  <b g>8 <c g> <c a> <d a>
  <d b> <e b> <e c> <f c>
  <f c> <e c> <e b> <d b> 
  <d a> <c a> <c g> <b g>
}

lowersFirst = \relative {
  <g b>8 <g c> <a c> <a d>
  <b d> <b e> <c e> <c f>
  <c f> <c e> <b e> <b d> 
  <a d> <a c> <g c> <g b>
}

\new PianoStaff \autochange \uppersFirst
\new PianoStaff \autochange \lowersFirst

___________________

0001-autochange.scm-Use-averaged-chord-pitches-to-determi.patch
Description: Binary data

current.png
Description: PNG image

revised.png
Description: PNG image