FYI: Status of Ancient Notation Implementation

[Juergen Reuter]

Hi all,

just for the record in expectation of lily 2.10, here is a summary report 
of known _NEW_ bugs in ancient notation that were newly introduced in the 
2.9.x series.  I list them here as a collective todo list, for myself 
remembering them easier, but also for anybody else interested in the 
status of ancient notation implementation.  I would like to see these bugs 
fixed, such that ancient notation at least does not get worse with each 
new release of lilypond, but my time is currently extremely limited; 
nevertheless, I will try having a look at one or another bug in the next 
couple of weeks/months.  Of course, any help is highly appreciated!

Mainly looking at the manual at the website (stamped as lily 2.9.21) and 
also considering the "longa notes" thread (cp. 
http://lists.gnu.org/archive/html/lilypond-devel/2006-10/msg00022.html), 
I currently see the following bugs that were introduced in 2.9.x:

* Section 7.7.7: The "episem" articulation does not appear (there should
  be a horizontal line above the three last noteheads).  In 2.7.x, the
  right ending was badly placed; now the episem is completely invisible.
  Also, the text scripts are colliding (but that is not really an ancient
  notation issue); they did not collide in 2.7.x.

* Section 7.7.9: The text scripts in the figure are unnecessarily widely
  spaced; the whole thing could be placed more tightly.  However, in lily
  2.7.x, it was placed too tightly, such that the text scripts were
  colliding.  So I am not sure, if the situation now is to be seen as an
  improvement or worsening.  Anyway, this issue is a general script
  placing issue rather than an ancient notation specific issue.

* Section 7.7.10.1, first figure: In HTML, the figure does not show at all
  (in PDF, it does; probably some arithmetic problem in spacing
  calculation that lets the bounding box of the figure horizontally
  collapse; cp.
  http://lists.gnu.org/archive/html/lilypond-devel/2006-06/msg00133.html).
  Actually, I am not sure, if this problem was not already introduced in
  the 2.7.x series.

* Section 7.7.10.1, second figure: Ligature brackets are not at all
  displayed anymore.  Same problem also in the introductionary Section
  7.7.10.

* Appendix D.5.2: Horizontal padding around divisio maior (the vertical
  bar-like line) is far too narrow.  Note, that the horizontal spacing
  looked (almost) ok, when Geoff Horton rewrote this template, cp.
  http://lists.gnu.org/archive/html/lilypond-devel/2006-03/msg00174.html,
  even though, at that time I already warned about possible problems...

* The "longa notes" bug (cp.
  http://lists.gnu.org/archive/html/lilypond-devel/2006-10/msg00022.html)
  has been tracked down to a general problem in output-lib.scm (see
  http://lists.gnu.org/archive/html/lilypond-devel/2006-10/msg00050.html
  for details).  However, to fix it properly, note-head::calc-glyph-name
  should be completely rewritten (i.e. add test for empty style value in
  case statement and handle it identically as "default" style; also
  replace "case" statement by completely different way of dispatch to gain
  speed, e.g. with a hashtable or alist or...), which goes beyond my
  scheme skills.  Any help from scheme/guile gurus is appreciated!

Finally, the good news: Meanwhile, I could partially solve the 
separation-item problems reported in 
http://lists.gnu.org/archive/html/lilypond-devel/2006-04/msg00313.html,
so I hope to eventually correct placement of augmentum dots for 
vaticana-style ligatures.

That's all for now...

Greetings,
Juergen