Re: Fix 1229 Ensure space around prefatory matter (issue4187043)

[Keith OHara]

On Mon, 14 Feb 2011 13:43:37 -0800, <address@hidden> wrote:

> My only concern with these changes is the barline avoidance (which you
> mention in the tracker as possibly a good thing).  There's one regtest
> which shows the problem: in `song-melisma.ly', some extra space has
> appeared in the second bar around `daah'.
That's my only concern, as well.   I do not think it wise to 'recede' the 
spacing height of LyricText to compensate, because I think will leave an 
unpleasant surprise waiting until someone uses a very tiny lyric font or 
something.

Lyrics are moved horizontally away from barlines *only* if the bottom of the 
staff is perfectly clean of notes.  A single note head poking out means that 
vertical spacing cannot press lyrics against the staff, which means that 
note-spacing can conservatively assume the lyrics will not encroach the 
forbidden 1-staff-space zone of the bar line, which means the note column need 
not be moved.  This evening I'll put an image showing the effect on the 
tracker, and ask explicitly whether this is a good thing or not.

What is simply fascinating, but not in a good way, is why so *much* space 
appeared before the 'daah'.  It has the same case as the symptom as Janek 
pointed out today.  The check for near-collisions in staff-spacing.cc decides 
to increase the spring length to the note-column containing 'daah', enough that 
it would be 0.3-staff-space from the bar line in tight spacing, but then in 
normal spacing we see a noticeable gap.
-Keith