Loose-lines honor padding between systems

Loose-lines honor padding between systems

When placing a loose line (e.g. Lyrics) at the top or bottom of a
system, include as a constraint the padding to the neighboring
system or markup.  Fix 1654.

[Trevor Daniels, 2011-05-24 10:11:03]

Looks ok to me, although I haven't tested it.
Need Joe's LGTM to push.

http://codereview.appspot.com/4553060/diff/7001/input/regression/page-spacing...
File input/regression/page-spacing-nonstaff-lines-between-2.ly (right):

http://codereview.appspot.com/4553060/diff/7001/input/regression/page-spacing...
input/regression/page-spacing-nonstaff-lines-between-2.ly:1: \version "2.13.42"
2.13.62

http://codereview.appspot.com/4553060/diff/7001/lily/include/page-layout-prob...
File lily/include/page-layout-problem.hh (right):

http://codereview.appspot.com/4553060/diff/7001/lily/include/page-layout-prob...
lily/include/page-layout-problem.hh:64: Element (vector<Grob*> const& a,
vector<Real> const& o, Real p)
use pad here too for consistency?

http://codereview.appspot.com/4553060/diff/7001/lily/page-layout-problem.cc
File lily/page-layout-problem.cc (right):

http://codereview.appspot.com/4553060/diff/7001/lily/page-layout-problem.cc#n...
lily/page-layout-problem.cc:545: // distance to the final line in the preceeding
system,
preceding

[joeneeman, 2011-05-24 10:28:02]

lgtm

[Keith, 2011-05-25 04:49:26]

Thanks for comments.
I'll wait one more day before I push.

[Carl, 2011-05-25 13:43:55]

IIRC, part of the motivation for the new spacing algorithm was the desire to put
staves in fixed positions on the page, regardless of what else was around.

Does this patch eliminate this possibility?  If so, is it possible to disable
it?  I guess by setting padding to 0?

[Keith, 2011-05-25 18:08:59]

On 2011/05/25 13:43:55, Carl wrote:
> IIRC, part of the motivation for the new spacing algorithm was the desire to
put
> staves in fixed positions on the page, regardless of what else was around.
> 
> Does this patch eliminate this possibility?

No. 
This patch merely includes a spring component, which should have been there all
along, to the spacing problem for non-staff lines at the top or bottom of a
system.  
Using line-break-system-details stuff overrides the springs, and there are lots
of regtests checking that it still works.

In fact, now I see the regtest that should have caught this issue 1654, if only
it had an active 'soft' spring component. I'll tweak that one to avoid adding a
new regtest.

[Carl, 2011-05-25 18:12:58]

On 2011/05/25 18:08:59, Keith wrote:
> On 2011/05/25 13:43:55, Carl wrote:
> > IIRC, part of the motivation for the new spacing algorithm was the desire to
> put
> > staves in fixed positions on the page, regardless of what else was around.
> > 
> > Does this patch eliminate this possibility?
> 
> No. 


Great!  LGTM.