Optimal page turning

Often it is necessary to find a page breaking configuration so that there is a rest at the end of every second page. This way, the musician can turn the page without having to miss notes. The ly:page-turn-breaking function attempts to find a page breaking minimizing cramping and stretching, but with the additional restriction that it is only allowed to introduce page turns in specified places.

There are two steps to using this page breaking function. First, you must enable it in the \paper block, as explained in Page breaking. Then you must tell the function where you would like to allow page breaks.

There are two ways to achieve the second step. First, you can specify each potential page turn manually, by inserting \allowPageTurn into your input file at the appropriate places.

If this is too tedious, you can add a Page_turn_engraver to a Staff or Voice context. The Page_turn_engraver will scan the context for sections without notes (note that it does not scan for rests; it scans for the absence of notes. This is so that single-staff polyphony with rests in one of the parts does not throw off the Page_turn_engraver). When it finds a sufficiently long section without notes, the Page_turn_engraver will insert an \allowPageTurn at the final bar line in that section, unless there is a ‘special’ bar line (such as a double bar), in which case the \allowPageTurn will be inserted at the final ‘special’ bar line in the section.

The Page_turn_engraver reads the context property minimumPageTurnLength to determine how long a note-free section must be before a page turn is considered. The default value for minimumPageTurnLength is \musicLength 1. If you want to disable page turns, set it to something ‘very large’.

\new Staff \with { \consists Page_turn_engraver }
{
  a4 b c d |
  R1 | % a page turn will be allowed here
  a4 b c d |
  \set Staff.minimumPageTurnLength = \musicLength 2*5
  R1 | % a page turn will not be allowed here
  a4 b r2 |
  R1*2 | % a page turn will be allowed here
  a1
}

When using volta repeats, the Page_turn_engraver will only allow a page turn during the repeat if there is enough time at the beginning and end of the repeat to turn the page back. If the repeat is too short then the Page_turn_engraver can be used to disable page turns by setting an appropriate value for the context property minimumRepeatLengthForPageTurn. In this case the Page_turn_engraver will only allows turns in repeats whose duration is longer than the value specified.

The page turning commands, \pageTurn, \noPageTurn and \allowPageTurn, may also be used at top-level, in top-level markups and between scores.

Predefined commands

\pageTurn, \noPageTurn, \allowPageTurn.

See also

Notation Reference: \paper variables for line breaking.

Snippets: Spacing.

Known issues and warnings

Use only one Page_turn_engraver per score. If there are more, they will interfere with each other.

See also

Notation Reference: Vertical spacing.

Snippets: Spacing.