Re: New slur/tie behaviour

[Han-Wen Nienhuys]

Werner LEMBERG wrote:
> >    I just type-set a piece using version 2.7.7 and this piece also
> > had some ties in it.  In this example I thought the new behavior was
> > a bit odd as I have two ties in a row but they are longer note
> > values and should they not appear at the same level? I noticed that
> > the change-log gives an example of this new feature but the first
> > note is tied to a very short note followed by a longer one.
>
>
> I second that.  Especially in chords, short ties are moved too much
> vertically from the `correct' place.  IMHO, this:
>
>   --___-------------___---
>    /   \   _____   /   \
>    \___/  /     \  \___/
>   ------------------------
>
> looks *really* bad.  A tie, regardless of being short or long, must
> not be placed completely between two staff lines if the notes are also
> between the same two lines.

It depends. I think it should, but only in crowded situations.

> For further references I suggest that you take a Henle or UE edition
> of Beethoven's piano sonatas (the later ones).

I agree that the Tie code is not optimal. Unfortunately, writing it 
already took it two to three times as long as I estimated (and was paid 
for), and I just spent another  1.5 hours debugging some problems. Now 
that it is more or less working, I have a better idea how the code 
should really have been written. I think it would probably be easier to 
do with a scoring based approach: generate all possible 
tie-configurations (TC, ie. all combinations of (Y, UPDOWN-DIRECTION) )

The number of TCs is

 M = (highest position - lowest position) * 2

Then, a single tie-column-configuration (TCC) for N ties is a subset of 
TCS with N elements. Counting tie-head distances, tie-tie collisions, 
tie-line collisions, and direction violations yields a score for a 
single TCC. Then we need to find the best-scoring TCC.

The number of TCCs is binom(M, #ties). A chord spanning a single octave 
with 4 ties already  yields 36000 different possible TCCs, so a brute 
force approach won't possible.  We'd have to use a some heuristics to 
generate  a limited number of sensible TCCs, and pick the best scoring 
one of them.

--
 Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen