make-tie-stencil: bug? and optional values?

[Thomas Morley]

Hi,

with
https://sourceforge.net/p/testlilyissues/issues/3088/
I implemented \undertie markup based on Jan's proposal.

I now wanted to use make-tie-stencil for other stuff and noticed some problems.

(1)
The local binding of slur-height, based on Jan's:

%% FIXME: c&p from bezier-bow.cc
#(define (F0_1 x) (* (/ 2 PI) (atan (* PI x 0.5))))
#(define (slur-height w h_inf r_0)
  (F0_1 (* (/ (* w r_0) h_inf) h_inf)))

Though, isn't there a wrong bracketing in slur-height?

In bow-bezier.cc it's:

Real
slur_height (Real width, Real h_inf, Real r_0)
{
  return F0_1 (width * r_0 / h_inf) * h_inf;
}

Shouldn't it be?
    (slur-height
      (lambda (w h_inf r_0)
        (* (F0_1 (/ (* w r_0) h_inf)) h_inf)))

Because my lack of C++-knowledge, I thought to better ask before
providing a patch.

(2)
The values of height-limit, ratio and angularity are hard-coded.

Any objections to make them optional, like:

(define* (make-my-tie-stencil
             start stop thickness orientation
             #:optional (height-limit 0.7) (ratio 0.33) (angularity 0.5)
             )
   [body]
)
(export make-my-tie-stencil)



Cheers,
  Harm