Re: Fingering position in polyphony face to sharp glyph. Bug?

[Thomas Morley]

2018-08-11 15:00 GMT+02:00 Torsten Hämmerle <address@hidden>:
> Thomas Morley-2 wrote
>> I tried to Y-center the Fingering-stencil.
>>
>> Though, with the example below the result is not all that convincing.
>> […]
>> Additionally, if fingeringOrientations contains 'left or 'right a
>> FingeringColumn is built at Staff-level, so the 'snap-radius-property
>> comes into play.
>>
>> No real clue how to proceed...
>

Hi Torsten,

this weekend I'll have not much time and I'll be completely offline
next week for holidays.

That said...

> Hi Harm,
>
> From my point of view, the Y-centering of the fingering stencil is perfectly
> OK (we just need a "proper" solution), the dot collision problem has
> bettered and can be completely cured by considering all the dots of the
> chord.

In my initial testing I experienced different behaviour, for no other
reason than different finger-numbers, i.e. small differences in their
extents.
Especially for right positioned fingers.
So I recommend thorough testings ...

>
> So, your remaining concern is the strange (?) behaviour of the
> FingeringColumn with respect to the snap-radius.
> This looks admittedly odd and I was wondering why the heck the outer
> fingerings don't come closer to their noteheads, respectively why are they
> arranged in a circular shape even if there is no accidental in the way.
> But, looking deeper into this, it is the expected behaviour and everything
> works as designed. If we don't like this, it would be another issue to
> change FingeringColumn algorithm, but, in any case, this is no unwanted
> side-effect of our stencil manipulations.

The curvy positioning is bad, imho.
But I agree it might be a different issue.

> To illustrate this, I've switched off any padding values, put a box around
> the fingering numbers and gradually changed the font size from very small to
> big in order to be able to observe the evolution of fingering placement.
> I've used just one flat because of its straight left border.
>
> <http://lilypond.1069038.n5.nabble.com/file/t3887/test-snap-radius.png>
>
> Starting off with a very small font size, there's enough space for each
> fingering to take its ideal Y-position, exactly centred on its notehead.
>
>
> *Rule: A fingering must never get in between accidentals and noteheads.*
>
>
> *In (1)*, the fingering "1" hardly touches the blue line signifying the
> lower end of the flat accidental. It still can stick to its notehead.
> Fingerings 2, 3, and 4 clearly have to go outside the flat and are pushed
> away from the notehead because of The Rule.
>
> *In (2)*, the font size has been increased so that the "1" just slightly
> gets into the "forbidden" flat area and therefore is pushed away from the
> notehead, too.  The "5" still has enough space.
>
> *In (3) and (4)*, the increasing height of the numbers starts spreading them
> vertically, away from their original Y position.  In (4), it is clearly
> visible that the "1" does not interfere with the flat anymore, but still (!)
> keeps its outside position.
>
> *In (5)*, finally, all the fingering number keep a distance from their
> noteheads, even if the "1" and the "5" are actually quite far away from the
> accidental.
>
> The (intended) reason for this is that, even if there seems to be enough
> space in the direct vicinity of their noteheads, these fingerings stay
> "outside" because at their original Y position, they'd get in between
> accidentals and noteheads. That's the simple reason why they stay "outside":
> their X position is determined by the accidentals, calculated as if the
> fingerings had their original Y position (i.e. the notehead's Y position).
> In a second step, their Y position will be spread out due to stacking, while
> keeping the X position.
>
> If there are more than on accidentals involved (or sharps with their more
> complex left skyline), the stacked fingerings may take on alignments along a
> curved path.
>
> In the end, snap-radius is used to avoid very small irregularities by
> positioning the fingering in a straight line if they have "nearly" the same
> X position to avoid an irregular, look.
>
> But, as I said, I consider this expected behaviour, even if it seems odd at
> first glance.
> Would you agree?

Yes, so far. :)

Thanks,
  Harm