Fret Diagram markup

[Carl D. Sorensen]

Attached is a copy of the latest fret diagram markup function.  It is
capable of accomplishing most of the requests that have been made on the
list, such as multiple fingering positions per string, labeling
fingering either through numbers in circles on the fret or numbers at
the bottom of the string, labeling the lowest fret on the diagram if
it's not fret 1, etc.

It's a fairly lengthy chunk of code to include at the front of a
lilypond file.  I think it might be reasonable to add as a scheme file
to the lilypond distribution, and create a new kind of standard markup,
fret-diagram-markup, rather than using a user-defined markup.  I don't
have CVS access (and in fact, haven't yet been able to get lilypond to
build on my Cygwin installation), so I don't believe I'm the right
person to move this into the lilypond distribution.  But if I should
become that person, I'll try to accept that responsibility.

I've been toying with the implications of developing a fret-diagram
context and engraver.  It seems to me that one of the major benefits to
having a context and engraver, rather than a markup, is that it allows
transposition to be applied to music expressions.  But I don't see how
transposition will work properly on the notes for a chord diagram.  If I
transpose from c to d, I don't want to play a C chord with all strings
up two frets.  Instead, I want to shift to a D chord, which has an
entirely different string structure.

I guess the message of all this is that to my way of thinking, the best
way to handle transposition with chord diagrams is to transpose the
chord name, then have a standard chord diagram based on the chord name.
Of course, special chord diagrams could always be entered as a markup.

Anyway, I hope this facility will be useful as-is.

Carl Sorensen

fret-diagrams.ly
Description: fret-diagrams.ly