Re: Ties between voices

[Lukas-Fabian Moser]

Hi Andrew,

Am 23.07.22 um 03:49 schrieb Andrew Bernard:

> I know
>       that we can't natively make ties between notes in different
>       voices. I know that there was a Google Summer of Code task that
>       could not be completed.
>       
>

A few weeks ago, I sent you the following privately (I was too timid to post in on the list):

My idea was to \consist the Tie_engraver to the Staff context not _instead_ of to the Voice context, but _in addition_. Then we have two Tie engravers and need a mechanism by which to tell if a given tie should be collected by the Voice-level Tie_engraver or at Staff level (in order to connect ties between different voices).

During my experiments I re-implemented the Tie_engraver in Scheme; although it turned out that (contrary to my expectations) the necessary adjustments could just as easily have been made in C++, the advantage is that we can test this approach without the need to re-compile a custom LilyPond build.

The attached file (requiring 2.23.6 and above) generates

as easily as:

\new Staff \with { \consists #New_tie_engraver }
{
  <<
    \relative {
      <c''~ c,\to Staff~>4 c8 b a g~ 4
    }
    \\
    \relative {
      s4 c'2 e4
    }
  >>
}

Of course the same mechanism might be implemented for, e.g., the Slur_engraver. But this requires additional work, as the slur positioning mechanism is not quite up to positioning Staff-level slurs correctly.

The attached Scheme Tie_engraver may be used as a drop-in replacement for the standard C++ Tie_engraver; in my local branch, it compiles the full regression test suite without causing differences.)

Lukas

tie-engraver.ly
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