Page layout is affected by previous pages?

[Mats Bengtsson]

The question from address@hidden provided a nice example
of a LilyPond problem, namely that the page breaking and system
spacing on one page seem to be affected by what happened on earlier
pages.

In the following example, you would expect the output to contain 4
equal pages, but what happens is that page 3 (which is in the middle
of the "piece") gets one score line less than all the other pages.
My only interpretation is that there is some memory between the
pages in the page breaking algorithm. In my opinion, the systems on
a new page should be typeset without any consideration of what has
happened on earlier pages.  I get the same results both with 2.6.3 and
2.7.12.

If you add a \pageBreak at the end of the definition of \onepage,
page 3 will get the desired 6 systems, but the problem moves to
page 4.

I have experienced a related problem earlier, where the first
2 movements of a piece fitted perfectly on 3 pages, but as soon
as I added a third movement, the last system of the 2nd movement
moved over to a new page, no matter what I tried. I can try to make
up a test file for this situation as well, if needed.


  /Mats


===============================================

\version "2.6.0"

\paper {
hsize = 21\cm
vsize = 27.5\cm
leftmargin = 2\cm
linewidth = 17\cm
topmargin = 1\cm
bottommargin = 0\cm
printpagenumber = ##f
raggedlastbottom = ##t
}

onepage = {
\repeat unfold 6 {
  \skip 1 \break
}
% \pageBreak
}

upper = {
\clef treble
\repeat unfold 4 {
  \onepage
}
}

lower = {
\clef bass
\repeat unfold 4 {
  \onepage
}
}

\new Score \with {
  \override TimeSignature #'transparent = ##t
  \remove Bar_number_engraver
} {
\new PianoStaff
  <<
    \new Staff {\upper}
    \new Staff {\lower}
  >>
}

\layout {
  indent = 0.0 \cm
}



--
=============================================
        Mats Bengtsson
        Signal Processing
        Signals, Sensors and Systems
        Royal Institute of Technology
        SE-100 44  STOCKHOLM
        Sweden
        Phone: (+46) 8 790 8463                         
       Fax:   (+46) 8 790 7260
        Email: address@hidden
        WWW: http://www.s3.kth.se/~mabe
=============================================