Re: Determining location of the staff lines

[Eric Knapp]

On Wed, Feb 3, 2010 at 10:19 PM, Carl Sorensen <address@hidden> wrote:
> On 2/3/10 8:38 PM, "Carl Sorensen" <address@hidden> wrote:
> Just a little more detail on this.  Stencils are always placed in relative
> mode, i.e. they are placed relative to other stencils.  They have an
> X-parent and a Y-parent.  So it's only necessary to know how to position a
> grob relative to its parent.  Hence, you don't need to know where the staff
> lines are; you just need to know where the string indicator needs to be
> relative to its parent (which is probably the center staff line).
>
> HTH,
>
> Carl
>

Hello, Carl.

Thanks for the replies, I have tried many things and I have run into
the limit of my knowledge. I can get your suggestions to work, but I
realized that the string markers are more complicated than I have
explained. Here's a more complete explanation.

The placement of the string markers in chords is not just dependent on
the string indications in the lilypond markup. I also have to know all
the pitches and all the strings together to place the markers. Here
are some examples in the linked images.

In the first image the interval is a fourth. This will mean
that the notes are played on the same fret on adjacent strings. In
this case the string markers are in parallel.

http://teachersdoor.com/images/stringMarkerShapes1.jpg

The second image shows a major third. This will be played on adjacent
strings and the higher note will be one fret lower than the lower
note. In this case the markers are drawn half overlapping. This shows
the shape that the fingers will make on the instrument.

http://teachersdoor.com/images/stringMarkerShapes2.jpg

The third image is a minor third. These notes will be played on
adjacent strings, but the higher note will be two frets lower. This is
shown with the markers drawn with no overlap, also showing  the shape
of the fingers on the frets.

http://teachersdoor.com/images/stringMarkerShapes3.jpg

This gets more complicated with chords of more than two notes. The
fourth image show a three-note chord with two notes on the same fret
and one on the next fret up. They are half-overlapped due to the major
third at the bottom of the chord.

http://teachersdoor.com/images/stringMarkerShapes4.jpg

And finally, the last image shows a chord with a minor third at the
bottom.

http://teachersdoor.com/images/stringMarkerShapes5.jpg

This will have markers that don't overlap. The final result of
all of this is that a Stick player can see very quickly what the
chords look like. A person who knows standard music notation can
ignore the special markups. Someone who maybe came from guitar and
only reads guitar tab can also learn the music and then start learning
standard music notation at the same time. The other benefit is that
the composer can communicate the full details of where to play each
note and with which fingers. On an instrument with 9 middle Cs, this
is very nice.

With this in mind, my string marker function needs to have all the
pitches and strings for a chord to determine where to draw the
markers. I'm envisioning a function that receives two lists and can
work out all the combinations. What I can't figure out is how to
capture the chord and all its data together. I'm getting all the
individual events, but that's not enough.

Am I making sense and what do you suggest?

Thanks again,

-Eric