Hi,
I found an article about music engraving* (in German):
http://pian-e-forte.de/texte/pdf/notenschreiben01.pdf
It claims a rule for accidental placement and shows some examples of how
chord accidentals are ordered on page 17 (second staff). This
corresponds mostly to what LilyPond does, except the chord in the 5th
bar (marked with "Here"). LilyPond follows the rule, that the lowest and
highest accidentals are placed closest to the chord. But the arrangement
of noteheads makes the author of the article change the order of the
lower two accidentals, which is easier to read in my opinion, because
the distance between the d sharp and its accidental is reduced (this is
an exception from the rule, the author stated before).
[to devel]
This does look good - I like the author's choice better than the LilyPond output.
For complicated chords, I'm guessing that it is often the case that LilyPond's current algorithm will miss the optimum result in some subtle way. Given n accidentals (where accidental is the whole group of things next to a note, including cautionaries, parentheses etc.), there are n! orders in which the most complete algorithm possible can place them. So once we're in 6-accidental territory, we're talking about 720 possible orders. It is possible to do accidental configuration "scoring" with a priority queue, very much how we do slurs. But I have no clue how much this would slow the program down.
Cheers, MS |