RE: guitar chord diagrams

[Carl D. Sorensen]

So, I've been working on making a Chord_diagram_engraver.  A few
questions:

1.  One of Chord_name_engraver's jobs is to find out the name of the
chord, which is stored as chord_name_, then typeset by
Chord_name_engraver::stop_translation_timestep().  I'd like to have the
chord name available to help me find a chord diagram; either one set up
by default or one previously entered in the music.  But I don't like
having Chord_diagram_engraver depend on Chord_name_engraver.  I also
don't like repeating the chord name search code in both
Chord_name_engraver and Chord_diagram_engraver.  This is why I
originally thought that adding a diagram feature to the
Chord_name_engraver would make sense.  Based on comments in the code, it
appears that the lilypond authors would prefer to have the engravers
separate, even if the cost is repeated code in multiple engravers.  Is
that correct?

2.  How do I get both Chord_name_engraver and Chord_diagram_engraver to
process the same music expression.  Is it just by having both engravers
in the context for the music expression?

3.  How might I be able to store default chord diagrams for common
cords, so that when a chord is entered, the diagram is already known
about by the engraver?

4.  Where would I look to find examples of routines that implement grobs
by putting TeX into the output file?

Thanks,

Carl

-----Original Message-----
From: Han-Wen Nienhuys [mailto:address@hidden 
Sent: Wednesday, February 04, 2004 12:50 PM
To: Carl D. Sorensen
Cc: address@hidden
Subject: RE: guitar chord diagrams


address@hidden writes:
> I also would like to develop guitar chord diagrams, and am willing to 
> do some programming to get them.

Great!

> I'd like a little sanity check before I dive in to the changes.  It 
> seems to me that the proper place to go is to make changes to the 
> chord_engraver so that instead of just listing a chord name, the grob 
> the engraver places included the diagram and the name.  Does this seem

> like a reasonable place to hang this capability?

No. Make a new engraver, Chord_diagram_engraver. You could copy & paste
code from Chord_name_engraver to get going easily.

-- 

 Han-Wen Nienhuys   |   address@hidden   |
http://www.xs4all.nl/~hanwen