Re: Switching the direction of slurs in tupletBracketToSlur (from Re: Unknown marking in Roman print (1710))

[Richard Shann]

On Mon, 2016-05-23 at 23:02 +0200, Thomas Morley wrote:
> 2016-05-23 16:27 GMT+02:00 Richard Shann <address@hidden>:
> > On Mon, 2016-05-23 at 10:13 +0200, Simon Albrecht wrote:
> >> On 22.05.2016 23:29, Richard Shann wrote:
> >> > I wonder did my email "Switching
> >> > the direction of slurs in tupletBracketToSlur" get overlooked or is
> >> > there no way that a direction can be set to be the opposite to the stems
> >> > and beams direction?
> >>
> >> Certainly it hasn’t been overlooked, and there is a way to do it.
> >
> > Spurred on by your confidence that it can be done I dug into it
> >
> > #(define (invert-direction x) (if (eq? UP 
> > (ly:tuplet-bracket::calc-direction x)) DOWN UP))
> > \override TupletBracket.direction = #invert-direction
> >
> > seems to do the trick.
> 
> Even more concise:
> 
> #(define (invert-direction grob)
>   (* -1 (ly:tuplet-bracket::calc-direction grob)))

This hinges on UP and DOWN never getting assigned different values. In
which case I see that 

#(define (invert-direction grob)
  (- (ly:tuplet-bracket::calc-direction grob)))

will work too.

> 
> > If anyone knows of a problem with this code,
> > please say,
> 
> Well, as soon as polyphonic happens it will produce strange output, see:
> 
> mus = {
>         \override TupletBracket.bracket-visibility = ##t
>         \override TupletBracket.direction = #invert-direction
>         \tuplet 3/2 { a'8 b c }
>         \tuplet 3/2 { r8 d e }
>         \tuplet 3/2 { r8 r f, }
>         \tuplet 3/2 { g, a'' r }
>         \tuplet 3/2 { c,,8 c c }
>         \tuplet 3/2 { r8 c c }
>         \tuplet 3/2 { r8 r c }
>         \tuplet 3/2 { c c'' r }
> }
> 
> \new Staff
> <<
> \new Voice \relative c'' { \voiceOne \mus }
> \new Voice \relative c { \voiceTwo \mus }
> >>

Thankfully my personal use-case doesn't stretch to that sort of
thing ...

Richard