Re: line-breaking bug in 2.19

[Janek Warchoł]

Hi,

2014-02-17 2:33 GMT+01:00 Keith OHara <address@hidden>:
> I put a version of the sources that works with version 2.19 at
> <http://k-ohara.oco.net/Lilypond/>
>
> With that version the short line is in the Trumpet part (not the Bassoon
> part).

Thanks!

2014-02-17 19:04 GMT+01:00 Keith OHara <address@hidden>:
> Tuplets are not required, so here is a closer-to-minimal example:
>
> \version "2.19.1"
> \new Staff \relative c' {
>   \override Score.SpacingSpanner.shortest-duration-space = #1.6
>   e16 f g e d c d e f e d c d e f e
>   g g f e d e c c f e e d e c c f
>
>   \break
>   e1 e e e }

I see that you beat me to it!  Sorry for being delayed again :(

But i have discovered something interesting with this example: the
threshold value seems to be exactly 5/3 - see this:

\version "2.19.1"

% breaks into 3 lines
\new Staff \relative c' {
  \override Score.SpacingSpanner.shortest-duration-space = #1.666666666666666
  \repeat unfold 32 f16
  \break
  f1 f f f
}

% remains in 2 lines, with ugly space in 2nd measure.
\new Staff \relative c' {
  \override Score.SpacingSpanner.shortest-duration-space = #1.666666666666667
  \repeat unfold 32 f16
  \break
  f1 f f f
}

The interesting thing is how the spacing behaves when the 16th notes
aren't broken into two lines: there's tons of space at the beginning
of the second measure, but not in the first measure.

I think that the mechanism of this bug is that Lily thinks that there
is lot of extra-stretchable space at the beginning of 2nd measure, and
so a break is inserted after 1st measure - but with the break, the
space at the beginning of m.2 somehow changes stretchability and is
not stretched.

Actually, the difference in stretchability of the
barline-to-first-note space indeed depends on the presence of time sig
and clef - see:

% now there will be ugly space in both 1st and 2nd measure:
\new Staff \with {
  \remove Time_signature_engraver \remove Clef_engraver
} \relative c' {
  \override Score.SpacingSpanner.shortest-duration-space = #1.66666666666666
  \repeat unfold 32 f16
  \break
  f1 f f f
}

i'll try to investigate more.

Janek

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