Re: accidentals for just intonation

[Paul Morris]

> On Dec 1, 2015, at 5:38 AM, Urs Liska <address@hidden> wrote:
> 
> You have a rather small number of individual components (vertical,
> horizontal and diagonal elements) that can all represented by a
> postscript path. A function should be able to determine from the input
> ratio which of these elements have to be combined and then generate the
> appropriate path and eventually use that to replace Accidental.stencil.

Yep, sounds like a matter of creating path stencils for each component part, as 
static unchanging building blocks, and then have a function that dynamically 
combines these stencils to produce the accidental needed for a given note.  
Combining stencils in different ways is simpler than producing a path on the 
fly, so that will make things easier.

I have done this kind of thing by creating an SVG with Inkscape and then 
opening the SVG file in a text editor where I can copy the path coordinates.  
Then I can paste those coordinates into a LilyPond include file, in a procedure 
that produces a path stencil.  (With some tedious back and forth to get the 
scaling right.)  Then that stencil is available to use by LilyPond.  

For Clairnote music notation I have code that replaces accidental signs with 
custom accidentals[0] that might be helpful to look at.  It combines a dot 
stencil with a line stencil, so no paths are needed.  However, I also use path 
coordinates to create whole note glyphs, so there’s an example of that as well. 
 That code is available here:

http://clairnote.org/software/

[0] http://clairnote.org/accidental-signs/

> How these paths can be created is something I won't be of much help, but
> if you get to the point where you have very concrete necessities you'll
> surely be able to get help by others with more experience in that.

There are several ways to create a stencil from a path.  Search the LSR for 
“path” for two different ways in addition to the \path markup command.  The 
most recent development version of LilyPond (2.19.x) also has a 
make-path-stencil function that combines the benefits of the two ways 
documented on the LSR without their drawbacks, so I prefer to use that unless 
I’m supporting LilyPond 2.18. 

-Paul