Re: slur corehack

[Thomas Morley]

2016-05-24 22:24 GMT+02:00 Flaming Hakama by Elaine <address@hidden>:
>
> I was trying to figure out why in lilypond, by default,
> slurs seem too shallow and run into accidentals.
>
> It seems like the state of the art is to tweak each slur individually
> using \shape to specify displacements from current control points.

\shape is a very nice tool.
This advantage inherits a disadvantage as well: other possibilities to
tweak a slur are more and more forgotten.

> Wouldn't it be better to change the defaults to something more suitable?
>
> I don't feel like modifying each shape is even a remotely reasonable
> workflow
> and I would rather treat the fundamental design issue.
>
> So, I decided to try corehacking the values in the file (this is OSX)
> Contents/Resources/share/lilypond/current/scm/define-grobs.scm
>
> After some iteration (since settings influence each other),
> I found that by just changing two defaults,
> I could get the vast majority of my slurs to be quite reasonable:
> increasing height-limit from 2.0 to 5.6 and increasing ratio from 0.25 to
> 0.36
>
> I am wondering if anyone else uses this approach?
> Clearly, changing the files in the distro has many things to not recommend
> it.
>
> But on the other hand, is there a code-based way to do this?
> (If so, this ought to go in the docs tout suite!)

The values in define-grobs.scm are the default-values for the
properties of the grob.
Each one can be changed using tweak or override.

/tweak and /override are documented.

You just could do:

\layout {
  \override Slur.height-limit = 5.6
  \override Slur.minimum-length = 2.3
  \override Slur.ratio = 0.36
}

Though, I doubt your proposal has a chance to be implemented, look at :

\layout {
  \override Slur.height-limit = 5.6
  \override Slur.minimum-length = 2.3
  \override Slur.ratio = 0.36
}

{
    c''1( d''1)
    \break
    R1
}

The Slur is far too high

> There are other things I'd like to change by default,
> especially the x locations of the center two control points,
> which are too close together.

Higher values for hight-limit will result in closer inner control-points.

> Also, when slurs and ties continue over the break, they are too short.

It's too late to think more about control-points/after-line-break
right now, need to find some sleep.
It would be a good idea to provide some examples, though.

Cheers,
  Harm