Re: Mensural notation - some questions and a patch

[Benko Pal]

Hi Jürgen,

> > 1. punctus divisionis
> 
> Hmmh, I haven't thought about this much by now.  Maybe, we want to 
> introduce a new type of breath mark; my main source[1] says, that punctus 
> divisionis can be thought of something similar like a bar glyph.

([1] is my main source as well.)  The main difference is that there is
never a line break at a punctus divisionis.

>  Of course, we have to think about the vertical aligning of this
> glyph (is it always aligned with the previous pitch or centered
> between the enclosing pitches or ...?).

It must be obvious that it is not a punctus additionis.  It is
generally a stave further from the note than an augmenting dot.  If it
is between minimae, than it's generally halfway between the stems.

> > 2. coloratio
> 
> The style property tweaking approach may be acceptable as a temporary 
> workaround.  However, for the long term, I would prefer a solution that 
> respects the musical meaning of colored notes.  Ideally, I would not have 
> at all to touch the style property, but just say something like "\times 
> 2/3 { ... }" within a specially prepared \context MensuralVoiceContext to 
> mark colored sections, and let lily do the rest.  Then you would get a 
> transcription into contemporary notation for free, and MIDI output still 
> would be ok (with pure style tweaking, MIDI output would be wrong).

This is far more difficult.  The length of a notehead depends on
context.  A colored note may be of the same lengh as its uncolored
counterpart.  (This is true for uncolored notes as well - a brevis may
be shorter than a semibrevis (e.g.

\time 9/2 r\breve c1 d1 r\breve e2 f\breve g2 a1 h2 r\breve

a is 2 minima long,
c is 3,
f is 4,
d is 6;
 
the keywords are imperfectio a parte post/ante and alteratio).)

> > 2a. a half-note in a coloratio section looks like a quarter-note.
> > To avoid this, sometimes quarter-notes are written as half-notes
> > with a flag.  Is there a command (bunch of commands) so that such
> > quarter-notes are used throughout?
> 
> Not yet, but given that we can find a reliable way to detect this case, it 
> should not be too hard to implement.

If such note-glyphs are used, then they are used exclusively during
the whole movement, so I think there is not too much to detect, let
the user ask for it, just like asking mensural or neomensural
note-head style.

> > 3. Current ligature handling doesn't conform to medieval-renaissance usage;
> > I implemented a new algorithm within the old framework.
> > This is in the attached patch (some comments later).
> 
> Yes, I know: the current implementation is quite buggy.  I implemented 
> ligature handling based on a finite state automata maybe two or three 
> years ago.  The crucial thing is that it is rather simple to handle the 
> ordinary cases, but hard to catch the unordinary cases of more 
> complicated rythmical patterns.  The idea of the automata was to catch 
> unordinary cases in a table-like approach, thus making it easier to add 
> new exceptions by just altering some entries in the tables (i.e. 
> minimizing side effects when fixing an uncaught case).
> 
> If your appraoch fixes the problems of my implementation, I will be glad 
> to throw away my buggy implementation.  I will have a look at your 
> implementation on the weekend (I am still busy co-directing a stage play 
> until this saturday morning).

Oh, that sounds interesting!

> > - last line (before a \break) not streching the whole page-width?
> 
> Try "raggedright = ##t".

However I want the full lines aligned.  And incomplete lines can
appear anywhere, not just at the end of page or end of file, so
raggedlast is not an option.

> > 7. Bigger note heads (in 15th century manuscripts a semibrevis head
> > is almost two staff-space wide)
> 
> We could introduce yet another set (i.e. style) of note head glyphs, but 
> before doing so, I would like to see some kind of standard or reference 
> (such as Petrucci's Odhecaton can be considered as a notational standard).  
> Otherwise, there is the danger of producing inflationary and maybe 
> incomplete sets of unrelated glyphs.

I've just seen \set fontSize, and will try.

> > Some notes about the patch:
> > this is my first submission to free software,
> > there must be a lot of issues with it.
> > E.g. I've written a description of the algorithm and a test file
> > (also attached), but don't know where to place them and how;
> 
> That's perfectly fine.  What has been really missing since my first 
> ligature implementation, is a comprehensive test file with many ligatures 
> for regression purposes.  Your test file looks like a good starting point 
> for such a regression test.  Thanks!

If you send me your concerns, I can look up other examples.

Thanks,
Pal