Re: alpha test, spacing ajusments

[Keith E OHara]

On Thu, 28 Oct 2010 09:01:26 -0700, Nick wrote:

> Actually, the vertical layout problem I reported a few weeks ago
> (http://code.google.com/p/lilypond/issues/detail?id=1252) still exists
> with 2.13.37.

The information in the bug tracker indicates that, when LilyPond plans how many 
systems to put on each page, she sometimes misunderestimates the space needed 
by rehearsal marks, and other such things that are logically outside the Staff 
context.  So we would expect sometimes the spacing algorithm will sometimes be 
asked to fit more on a page than is possible, especially in single-staff parts 
with volta repeats and marks.

If we restrict our efforts to cases where .37 simply does a bad job arranging 
staves that *could* fit nicely on the page, such efforts should not be wasted.


Now, a user might be pro-active and think,
"Let me just tell LilyPond that I don't need her to try to pack so many staves 
on each page in this particular score:
 system-system-spacing #'space = 20 % staff spaces  (or between-system-space = 25\mm 
in stable 2.12) "

Alas! LilyPond does not change her page-break decisions based on our requested 
space (with any of the page-breaking algorithms) (though she does layout pages 
differently in response to between-system-padding).


Nick,
 Since it seems you actually let LilyPond choose page breaks for you, do you 
have any ideas for how to set defaults so that issue 1252 appears as rarely as 
a sunny day in Glasgow ?   (I gave up on page-breaking-system-system-spacing 
because it seems to affect the page breaker in the same ineffective way as 
system-system-spacing.)

 No lack of confidence in the developers, of course, but it could happen that the only 
true repair for issue 1252 is "LilyPond will just have to do a detailed trial layout 
in the planning phase, no more guessing, taking about twice as long to set scores."
-
Keith