Re: [frogs] bend implementation

[Carl Sorensen <c_sorensen@xxxxxxx>]

On 2/2/10 1:34 PM, "Marc Hohl" <marc@xxxxxxxxxx> wrote:

> Carl Sorensen schrieb:
>> If you're not going to add a bend-event to each note, e.g.
>> 
>> c d\bend-1 e\bend-2 f\bend-2.5
>> 
>> (which I think doesn't work well, because decimal bends is not a good idea)
>>  
> This seems not to be very useful - I wanted to let lilypond do the work,
> i.e.
> computing the bend amount, deciding whether the bend arrow points
> upwards or downwards (in case of tablature, of course), and this is what you
> proposed with your "autobend" approach, isn't it?

Sort of.  The point I was making earlier is that a bend is *not* between
pairs of notes.  A bend is away from a reference note, which may not even
appear in the score (like in the case of a pre bend).  So somehow a bent
note needs to have two pitches associated with it:  the reference note and
the actual note.  I think the fundamental approach that says "use the
previous pitch as the reference" is wrong; I think that all the bends should
be relative to the unbent note.  But I'm  not an expert in this, so I could
be wrong.

The bend indicators clearly go between two notes.  That's why they are
spanners.  But the amount of bend is a property of a particular note (based
on a reference which may or may not be the adjacent note).  So we need to
have a bend characteristic associated with a note that is bent.

My initial proposal was to have a bend articulation on a note just like we
have finger and string articulations on a note.  The bend articulation could
be automatically calculated in a function, just like string and fret are
automatically calculated in tablature, if they're not hard-coded in the
input file.  But when I started to think about what a bend articulation was
like, I didn't like it as a hard-coded value.

That's what got me to the BendMusic expression.  It would have a data
structure that could store the reference pitch (or alternatively, the amount
of bend) in the form of a pitch object, which is readily available in scheme
but not in the .ly file.

Anyway, you don't have to use any of my ideas.  I'm just trying to help.  If
the ideas are not right, feel free to ignore them.

Thanks,

Carl


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