Sacred Harp engraving

[Adrian Mariano]

I was delighted to see that Lilypond now supports sacred harp style shaped note
heads. I dusted off some old files I wrote for lilypond 1.2 to give it a try.
The result is very good, without some of the flaws I've seen from other systems
which mishandle the triangular noteheads, or force the user to specify the
shapes individually, making note shape errors possible. (A recently published
songbook has a 1.5 page long errata list where most of the mistakes are a wrong
shaped note, something that is confusing to people who rely on the shapes.)  

However, I did find a few things that could be improved. 

For reference I have temporarily posted to my web page the following items.  A
couple pictures taken from The Sacred Harp of a particular composition, showing
what I believe to be the best engraving for this type of music.  Also posted are
my lilypond input file and the lilypond output file for the same composition.  

http://members.cox.net/jsam/music/fullpage.jpg
http://members.cox.net/jsam/music/closeup.jpg
http://members.cox.net/jsam/music/newpoland.ly
http://members.cox.net/jsam/music/newpoland.pdf

Sacred Harp notation uses four shaped note heads.  In the major, the tonic is a
triangle and then proceeding up the scale you have circle, square, triangle,
circle, square, diamond.  In the minor, you assign the shapes to keep the same
interval relationships, e.g. you assign them for the relative major.  (This
means that the scale in the minor gives the tonic a square.)

1. The command \sacredHarpHeads gives the wrong shapes when the key is minor.  I
had to switch the key to the relative major in my example to obtain the right
shapes. One simple fix would be to supply two commands, \sacredHarpHeadsMinor
and \sacredHarpHeadsMajor.  I was wondering about the possibility of writing a
conditional to get the right shapes with a single command. However, there is a
complication: Dorian mode melodies are still given the shapes for the Aeollian
mode (tonic is square).  The simple solution of two commands may be best.  

2. Whole notes look funny.  The problem is that they are stretched out
horizontally, which makes the triangles look too sharp and pointy and the
squares look strangely skinny.  My example doesn't have a whole note diamond,
but I'll bet that would look really weird stretched out.  The regular whole note
is wider than the half note head.  But if you look at my reference page, you'll
see that the whole notes are the same as half note heads. Is there a way to
specify that whole notes should look exactly like stemless half notes?  (It
might be appropriate to wrap this in to the \sacredHarpHeads command.)  

3. My third comment is the most subtle and least important issue: the font for
the square and triangular notes could be more elegant.  If you examine the
shaped notes in my reference, you'll see that the horizontal lines are heavier
weight than the non-horizontal lines. This helps them stand out against the
horizontal staff lines.  It is also similar to how the round notes are not drawn
with a uniform line width circle, but with a tapering line.  It looks like the
diamond note head also has varying weight on its lines, similar to how it is
engraved in the Sacred Harp.