Re: "Spanner-context" GSoC project, mentor needed

[Trevor Bača]

Hi Urs,

While I don't have skills required to mentor this project, I'd like to
chime in to say that I think the project is valuable.

Decoupling spanners from (a single) LilyPond voice makes sense, as you
point out, in any sort of polyphonic context, even in very traditional
scores. Additionally, many contemporary scores use spanners quite heavily
(multiple spanners overlapping in a single voice, starting and stopping all
over the place, to indicate things like continuous changes of bow position,
bow pressure, air pressure, relative amounts of noise versus tone, etc etc).

So that's it: I just wanted to add that my own perspective working with
very recent scores reinforces the value of the project.

Thanks for initiating the discussion on this one and I hope solid
mentorship appears for the summer.

Trevor.

On Tue, Mar 8, 2016 at 3:07 AM, Urs Liska <address@hidden> wrote:

> Hi devs,
>
> we have a potential student looking for a GSoC project
> (http://lists.gnu.org/archive/html/lilypond-devel/2016-03/msg00006.html
> and following messages). He has expressed interest in the "Allow
> spanners to cross voices" project where I am listed as
> potential/secondary mentor. However, I have said that I can't provide
> that service without at least one primary mentor who feels fully qualified.
>
> As probably not everybody is really up to date with that project I'll
> outline a few things about it below. I would be really glad if someone
> steps up, if not to volunteer as mentor then at least to discuss the
> project and possible implementation approaches.
> It may happen that we'll have more applications than slots this year,
> but it would be unacceptable to prevent an application due to lack of
> mentorship.
>
> Problem:
> Spanners (dynamics, curves, text spanners etc.) have to be contained
> (i.e. start and end) in one voice. This doesn't reflect musical reality
> for all inherently polyphonic instruments. Additionally it is a PITA
> when working with combined parts.
>
> Solution:
> We have to find a way to make LilyPond recognize spanners that cross
> voices/contexts. This would make the ugly hacks with hidden voices
> obsolete.
>
> Note:
> This is *not* related to the engraving, as this already works properly
> (when the hidden voice is applied), so it is only related to *parsing*
> the input.
>
> Possible approaches:
>
>   * Let the beginning of the spanner specify a (named) target context
>     for the end of the spanner
>   * Give the spanner an ID that can be specified at the beginning and
>     the end
>
> I would suggest to implement both approaches and let the user choose
> which is appropriate for the given document. In particular I would like
> to see the ID approach implemented as part of this GSoC project because
> we'll need that for other purposes as well: enabling the
> edition-engraver to address items by ID and engraving from MusicXML/MEI.
>
> Urs
>
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>



-- 
Trevor Bača
www.trevorbaca.com
soundcloud.com/trevorbaca