Re: BendBefore / BendSpanner examples?

[Thomas Morley]

Am So., 31. Mai 2020 um 16:24 Uhr schrieb Wim van Dommelen <mail@wimvd.nl>:

Showing LilyPond to a friend is sometimes tricky. The question: "Oh, can it do this or that?" easily pops up.

I "survived" the BendAfter question, but had to let go for a BendBefore (or 'doit'?) example.

Diving in at home later that day I found some interesting things done with a new(?) BendSpanner-grob for a guitar, and several people having put a bounty for further work on this. This goes back to 2013, 2016, 2019, apparantly not an easy question. The BendSpanner-grob example goes way behind what I probably ever will need, in fact I would probably have enough with the coding for (some of) my examples.

I've extracted 3 examples in 3 .PNG-files, attached. If you want I can also put a bounty out for this ($25 for each example via PayPal?, first come, first serve). My bending is aimed at a bass clarinet, but that is probably irrelevant for you.....

The 3 examples:

1:

(the bar-number "12" is irrelevant, btw.)

2: 

3:

Can someone help me?

Regards,

Wim.

Hi Wim,

the BendSpanner-grob is not in the source and was done for Tabs only.

Pierre already posted some suggestions.

Her my own, affecting RepeatTie:

#(define repeat-tie->bend-before
  (lambda (rt)
    (let* ((cps (ly:grob-property rt 'control-points))
           (thick (ly:grob-property rt 'line-thickness 0.1))
           (details (ly:grob-property rt 'details))
           (gradient (assoc-get 'gradient details '(0.8 . 1.5)))
           (left-space (assoc-get 'left-space details 0.5))
           (height (assoc-get 'height details 0.7))
           (cp-1 (car cps))
           (start
             (cons
               (- (car cp-1) (car gradient))
               (- (cdr cp-1) (cdr gradient)))))
      (ly:grob-set-property! rt 'X-extent (cons (- (car start) left-space) 0))
      (make-tie-stencil start (last cps) thick DOWN height))))

bendBefore =
  <>
    -\tweak stencil #repeat-tie->bend-before
    _\repeatTie
   
%%%%%%%%%%%%%%%%%%%%%
%% Examples
%%%%%%%%%%%%%%%%%%%%%

{
  c''4
  \bendBefore
  c''
}

%% customizing possibilities

{
  c''4
  \override RepeatTie.details.gradient = #'(0.5 . 0.5)
  \bendBefore
  c''
}

{
  c''4
  \override RepeatTie.details.left-space = 1
  \bendBefore
  c''
}

{
  c''4
  \override RepeatTie.details.height = 4
  \bendBefore
  c''
}

{
  c''4
  \shape #'((0 . 0) (0 . 0) (-0.5 . 0) (-0.5 . 2)) RepeatTie
  \bendBefore
  c''
}

Cheers,

  Harm