Re: Issue 1329 in lilypond: \afterGrace placement/behaviour to be discussed

[lilypond]

Comment #1 on issue 1329 by address@hidden: \afterGrace  
placement/behaviour to be discussed
http://code.google.com/p/lilypond/issues/detail?id=1329

AFAICS The behaviour is consistent with the documentation  
(http://lilypond.org/doc/v2.13/Documentation/notation/special-rhythmic-concerns.html  
section 'Grace notes').
But I also find it strange.
While the example in the docs  
(http://lilypond.org/doc/v2.13/Documentation/2d/lily-cde62d5a.ly) looks  
quite good (when there is no other staff), the examples in the report show  
where the problem is:

"If you want to end a note with a grace" lets me expect the following  
behaviour:

From the musical perspective the afterGrace note(s) immediately precede the  
note following the main note. That is, if I have
   \afterGrace d1 { c16[ d] } c1
I'd expect the grace notes to be aligned to the right bar line.
From the docs I would assume that \afterGrace by default should start after  
a 3/4 space and uses the remaining 1/4. By changing the fraction one would  
then stretch or compress the grace notes.
A grace note that ends a main note also shouldn't be coordinated  
rhythmically. It shouldn't
influence the rhythmic placement of other staves/voice (which is different  
from grace notes before the main note).
I also think that \afterGrace notes should by default not have an explicit  
duration but should rahter use up just the space that is needed for the  
notes itself.


The actual behaviour is the following:

The attached example shows that the grace notes are musically aligned like
<<
  { d1 } //
  { s2. \grace { c16[ d] } s4 }

thus also forcing spaces in the middle staff.

so \afterGrace is in fact a function to place grace notes arbitrarily after  
a note (instead of "ending" it).

If this is the behaviour the developers intended then it should be made  
more clear in the doc.

However I would suggest to change the behaviour to what I outlined above:
- \afterGrace places the grace note(s) at the end of the main note.
- by default it shouldn't have an explicit duration but just use up as much  
space that is needed for the grace notes.
- by explicitly setting a fraction the grace notes are stretched/compressed  
to that ratio or duration.
- the grace notes don't affect the placement of objects in other  
staves/voices
If one deliberately wants the current behaviour it can still easily be  
achieved by the two-voice construct I wrote above.