Re: Part combiner & Stem direction, w/patch

[Jan Nieuwenhuizen]

Ted Ashton <address@hidden> writes:

> Well, having gotten a build environment put together, I've spent the day
> working over the part combiner.

Thanks for looking into this.  I apologise for my late reply, I have
been very busy.  The part-combiner is slated for a full rewrite, but
that may not happen any time soon.

Currently, the part-combiner is used in three different situations:

  1. orchestral score/part wind section (soloADue mode, the default)
  2. orchestral score/part string section (soloADue mode, aDueText = #"")
  3. hymns (not soloAdue)

and the idea with changeMoment was to allow:

  4. orchestral score/part bassi section, combining the violoncello and
     contrabasso Staffs, instead of the usual )oice

but that has never been operational.

The biggest problem currently is that the specifications are not well
defined.

> In specific, I changed:
>   1) When soloADue is off, the stems of part "two" in split intervals now get
>      pointed down, they didn't before.

This seems to be a good fix.

>   2) When one part has a long rest and the other has note during it (for
>      example, an r4 in part "one" and r8 d16 r16 in part "two"), the smaller
>      rests were getting cut

And this too.

>   3) I also did considerable cleanup to make things work when changeMoment is
>      set to something other than the default.
>
>      This work is still not complete.
>      Under known bugs should go that if you set it to 1/8,1/8 and you have, 
>      for example, four 16ths barred together, weird things can happen 
> including
>      losing notes.  Fixing that is beyond my currently available time and
>      knowledge.  It does work exceedingly well if you set it to 1/4,1/4, 
> though
>      and, so far as I can tell, still works as before (with the exception of
>      fix 2 above) when set to the default.

Ok.  Yes, changeMoment is hairy.

I've tried your patch, but it changes the behaviour in soloADue mode.
`a2' and `solo X' texts get printed after each rest of both voices,
even if the state does not change.  This is different from what I've
seen in orchestral parts; it clutters the page with texts.  If that is
what you need, it should be made optional.

> I would be happy to help write docs/regression tests/samples on the changes,
> but need guidance as to format/location/etc.

The documentation is in texinfo.  There is a section on the
part-combiner in Documentation/user/refman.itely.  It should not be
too hard to add information there.

It would be very nice if you would want to help writing a
specification for what the part-combiner should do, ie, when to print
texts, when to combine or split voices.  For example, in soloADue
mode, going from a Solo part to a A Due part, you only want to print
`a2' when both play the same note.

> I'll attach the patch which is against the stable release source (the cygwin
> lilypond source package).  Three files are affected.  The changes to
> a2-engraver are just to get the stems pointed correctly.

Thanks, but I can't put this in right now.  Do you want to look into
the changed behaviour and could you also add a ChangeLog entry?

Greetings,
Jan.

-- 
Jan Nieuwenhuizen <address@hidden> | GNU LilyPond - The music typesetter
http://www.xs4all.nl/~jantien       | http://www.lilypond.org