Re: Contemporary music required feature #1: chromatic transposition

[Hans Aberg]

On 22 Sep 2009, at 15:00, Carl Sorensen wrote:

> If you get the chromatic transposition working properly, I'll commit  
> to
> helping you get it embedded in LilyPond.

My impression is that this works properly, only that LilyPond does not  
have the capacity to treat # and b as operators that can be iterated.  
Right now, I think, it just looks up the offset, and reports an error  
if no glyph is found for that offset.

The missing glyph problem could be fixed by LilyPond then continuing  
and, if the offset is positive, subtracting a #, and then makes a new  
glyph lookup; and so on, until the offset becomes negative, and first  
then reports an error. Otherwise, print the number of #'s and the  
accidental.

> It will be not difficult to implement this in core LilyPond.
>
> Presumably there will be some sort of normalize-pitches function,  
> which will
> take a staff position with with alterations and, based upon the key
> signature, turn it into a different staff position and alteration that
> represents the same pitch.
>
> Different normalize-pitches functions can be written for different  
> behavior.
>
> A property representing the normalize-pitch function can tell the  
> code which
> function to call.
>
> It will be necessary to add a property (easily done), and add the  
> property
> to an interface (also easily done).

For this, I think he just wants a version of the naturalizeMusic that  
applies E12 enharmonic equivalence if the offset is greater that two  
sharps, so one does not have to display a doublesharp plus a  
microtonal raising accidental. Though there is the case of say E#+ -  
should that be replaced by F+?

  Hans