Re: converting svg glyph to path data for use in scheme (was: accidentals for just intonation)

[Graham Breed]

> From: Urs Liska<address@hidden>

> > >Maybe so, but the result is less portable because (if I understand
> > >correctly) you'd have to have a custom font and have it installed
> > >correctly, etc. for anyone to be able to use the glyph...  as opposed
> > >to just having the custom glyphs in an include file that you?re going
> > >to be including anyway.
> > >
> > >-Paul
> I think the font idea*may*  be an approach worth considering.
>
> Our stuff will reside in a library anyway, and I think it should be possible to 
> have that library call a font reliably when it is in the same directory IIRC.

I can get fonts from the current directory no problem on Linux.  But 
there's a problem with Windows that I still haven't looked into. 
There's surely a way around it, though.

> We could then have a font with glyphs for each constituent of your accidentals 
> and construct the actual accidental as a markup using \combine, which should be 
> pretty straightforward.

If the glyphs are pre-built, a font file is the obvious place to store 
them.  If they have to be combined, it's a bit harder because it has to 
be a text font, but this problem is also solved.  There's a problem with 
more recent Lilyponds where the accidentals can collide with barlines, 
but if you can pin it down and report it I'm sure that can be fixed.  I 
think the rules for combining symbols into glyphs can all be written 
into the font files but that may not be the easiest way to do it.

The nice thing about fonts, though, is that some already exist.  The 
problems with generating large lookup tables, or multiplying ratios, or 
factorizing this or that, can all be solved with the Extended 
Helmholtz-Ellis JI system, and when everything's working you can drop 
the new glyphs or start drawing them some other way.

It's nice that you think keeping the primes distinct is straightforward. 
 I thought it was difficult, especially if you want MIDI playback and 
transpositions to be correct, but not impossible.

A large lookup table, corresponding to a sensible equal temperament for 
wraparound, is probably the best way to get started.  The system is 
potentially infinite, but you can set limits on how far you expect 
modulation to go.  People keep being pessimistic about Lilypond or 
Scheme's performance with large tables but so far nobody's produced a 
huge table and demonstrated it to be unacceptably slow.


                  Graham