Re: Spacing problems with 2.9.21 (as opposed to 2.8)

[Joe Neeman]

On Thu, 2006-10-12 at 02:37 -0400, Marcus Macauley wrote:
> Joe Neeman <address@hidden> wrote (earlier):
> > You can enable the old page breaker by
> > putting #(define page-breaking optimal-page-breaks) in the \paper block.
> 
> I tried this command, and it seemed to work for vertical spacing  
> (restoring mine to the way it was with 2.9.17), but I notice that the  
> horizontal spacing has also changed (spread out slightly) in 2.9.22, from  
> 2.9.17.
> 
> I prefer it the way it was, unless there's a good reason for the change  
> (which, then, I think should be described somewhere).

There was a good reason (which can be found by searching the
lilypond-devel archives for "compression penalty"). But I think there is
a better solution for the problem: I make the compression penalty
configurable and assign different defaults depending on which page
breaker we use. The page-turn-page-breaker gets a big penalty and the
others get a small (or even no) penalty.

I was a little reluctant to make the penalty configurable because it is
something internal to the line breaker and I think it shouldn't need to
be modified by the user. But this way it should give good results in
most cases without modification.

Here's a suggested patch (untested)

2006-10-17  Joe Neeman  <address@hidden>

        * lily/page-turn-page-breaking.cc (Page_turn_page_breaking): set
        a higher default for compression-penalty

        * lily/simple-spacer.cc:
        * lily/constrained-breaking.cc:
        make get_line_forces and get_line_configuration take a
        compression_penalty parameter.

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