Re: BendSpanner-engraver

[Marc Hohl]

Hi Harm,

Am 13.09.2016 um 22:41 schrieb Thomas Morley:
[...]
> Even if I wouldn't want to take one I'm forced to: my regular job
> started after summer-break :((

For me, too :( And -as ever– the TODO list for doing stuff within the 
summer break is still not completely done.
[...]
> > The customization features are great! Also, I like the dashed line of the
> > pre-pend-hold use cases.
[...]
> Looks doable, I'll probably try the upcoming weekend.#

Great!

>
[...]
> Well, we can't expect a user to find his way to this coding, maybe
> some predefined function, will do it!?
>
> > I hope to find the source somewhere to provide you a scan of how it should
> > look like.
>
> Would be great.

Still searching ...
> > ---
> >
> > Another idea/thought/proposal: IIUC, the engraver does not take the string
> > numbers into account. I think this would be a good feature from a user's
> > point of view:
> >
> > c'\startBend d'\stopBend\startBend c'\stopBend
> >
> > could then probably be simplified to
> >
> > c'\3\startBend d'\3 c'\3\stopBend
>
> You may have noticed the file bend-music-functions.ly being remarkable short.
> Coding shortcuts and appending them to the bend-music-functions-file
> is on the TODO
>
> Something at the lines of:
[...]
> This is a very first shot, more a proof-of-concept...

This is possible, but I don't think that shortcuts are sufficient here.

Some years ago I had long discussions on the devel list concerning the 
implementation of a string-bend-engraver (that would have had to be done 
in C++ at this time), especially with Carl Sorensen, and we came to the 
conclusion that a bend event is something that happens *to a certain 
string*, therefore it is possible to bend a string, keep it bent, bend 
another one, release it and then release the first bent string again.

This is rather complicated stuff, but some guitarists do stuff of this 
kind ;-)

[...]
> I considered it already.
> Though, the engraver mimics the behaviour of TextSpanner.
> And you can't start a TextSpanner inside EventChord.
>
> I didn't figure how to do it different.

We discussed about that as well ;-) I tried to follow the slur engraver, 
but this is one of the more complicated engravers, so I finally gave up ;-)

Technically speaking, the mimics of the slur engraver seem ideal if you 
see it as a per-string basis: you cannot have two simultaneous bends on 
one string, but you can bend each string independently.

> I have a suspicion about the slow down...
> Will test as soon as I have some spare time, though it's a highly
> complex and huge coding.
> Sometimes I feel like touching the limits of my current coding skills.
> Proceeding means to do all very carefully and thoroughly and _not_ in
> any hurry ;)

Of course! As already said, I was working on the concept of a 
string-bend-engraver for about 1 1/2 years or so, and the ideas and 
concepts are still (mostly) available. I'd be glad to help you with this 
task, but some private messages in German language could be perhaps more 
effective here ... ;-)


[...]

> Although, guitar-player myself I never use TabStaff
> rofl

My pupils are fond of tablatures, easy available, easy to understand ...
And trying to write down a contemporary guitar solo with normal staves 
only is a bit of a nightmare ;-)

Cheers,

Marc