Re: LilyPond and visually impaired accessibility

[Reinhold Kainhofer]

Am Donnerstag, 24. März 2011, 15:07:54 schrieb Han-Wen Nienhuys:
> I think it would be awesome to have MusicXML output, but I am not sure
> about the technical constraints.  IIRC, MusicXML has a complicated way
> of mixing layout and abstract music information, that would make it
> difficult to produce fully fledged musicxml from LilyPond easily; 

Actually, MusicXML 1.0 was just about musical content, which is not too hard 
to produce in lilypond. MusicXML 2.0 added lots of attributes for display, 
exact item positioning, layout etc. MusicXML does not require applications to 
export exact positioning and layout information, so for now exporting only the 
musical content is fine. Just look at most of the files in 
input/regression/musicxml/ for examples. 

As a first step, it would suffice to only export the musical content (part-
wise, i.e. at the Staff/PianoStaff level).
The second step, exporting the exact positioning and layout information is 
much harder, as that information is only available at the very end of 
lilypond's processing, when you don't have easy access to the music events any 
more. I.e. you don't have the link between the grob (with its exact position) 
and the musical event that caused it (which will be the XML element exported 
to the MusicXML file).

Of course, there are several problems:
-) All lyrics are always contained in a part (i.e. a staff). There is nothing 
like the stand-alone Lyrics context in lilypond.
-) The same goes for FiguredBass etc.
-) All staves inside a PianoStaff should be exported as one part, while all 
other staves are exported as separate parts.
-) All Staves start at the very beginning and end at the very end in MusicXML 
(of course, you can hide them for some portions of music).
etc.

Cheers,
Reinhold



-- 
------------------------------------------------------------------
Reinhold Kainhofer, address@hidden, http://reinhold.kainhofer.com/
 * Financial & Actuarial Math., Vienna Univ. of Technology, Austria
 * http://www.fam.tuwien.ac.at/, DVR: 0005886
 * LilyPond, Music typesetting, http://www.lilypond.org