Re: Issue 1127 in lilypond: Piano staff centred dynamics

[lilypond]

Comment #3 on issue 1127 by address@hidden: Piano staff centred  
dynamics
http://code.google.com/p/lilypond/issues/detail?id=1127

Attached is a hand-engraved example of centred dynamics from a piano score  
[1]. The individual dynamic marks are centred between the skylines by  
shifting the baseline as needed. In contrast, the current behaviour [2]  
uses a Dynamic context that aligns every dynamic to the same baseline,  
often forcing the music to take up much more space than necessary.

In principle, the desired output could be achieved by using the adjacent  
system skylines to vertically position the grobs within a Dynamic context  
and then the existing vertical layout can still be used to position the  
context between the staves (afinity = #CENTER). The vertical positioning  
would be taken from the average of the two skyline offsets, e.g. if the  
right-hand music takes up 3 spaces below its staff, and the left-hand music  
takes up one space above its staff, the dynamic at that position should be  
shifted down one space from its default position.
  ((-3) + (+1)) / 2 = -1
The tricky part is that the upper and lower staves must be laid out before  
the dyanamics, and the Dynamics engraver must have access to those skylines.

At least, that's how I understand this issue.

-Andrew


[1] Beethoven, Sonata 13, Edition Peters.  
<http://imslp.org/wiki/Special:ImagefromIndex/30364> This edition is also  
an excellent example of dynamics that intentionally impinge on the staff  
lines to allow tighter page layout.

[2] e.g.  
http://lilypond.org/doc/v2.14/Documentation/learning/piano-templates

Attachments:
        piano-centred-dynamics.png  23.6 KB