4.3 Breaks

4.3.1 Line breaking

Line breaks are normally determined automatically. They are chosen so that lines look neither cramped nor loose, and consecutive lines have similar density.

To manually force a line break at a bar line, use the \break command:

\relative c'' { c4 c c c | \break c4 c c c | }

By default, a \break command inserted in the ‘middle’ of a measure will be ignored (and a warning message will be output during the compilation of the LilyPond file). Adding an invisible bar line – ‘\bar ""’ – before the \break command will force the issue:

\relative c'' { c4 c c \bar "" \break c | c4 c c c | }

A \break command that occurrs at a bar line will also ignored if the previous measure ends in the middle of a note (e.g., when a tuplet begins in one measure and ends in another). In this case remove the Forbid_line_break_engraver from the Voice context and, use a simultaneous music construction inserting the \break at the appropriate place in the second ‘voice’:

\new Voice \with { \remove "Forbid_line_break_engraver" } \relative { << { c''2. \tuplet 3/2 { c4 c c } c2. | } { s1 | \break s1 | } >> }

Similarly, by default, line breaks are ignored when beams cross bar lines. Use the \override Beam.breakable = ##t command to force this:

\relative c'' { \override Beam.breakable = ##t c2. c8[ c | \break c8 c] c2. | }

The \noBreak command will prevent a line break at the bar line where it is inserted.

Within a score, automatic line breaking is prevented within music lying between \autoLineBreaksOff and \autoLineBreaksOn commands. If automatic page breaks should also be prevented, the commands \autoBreaksOff and \autoBreaksOn should be used. Manual breaks are unaffected by these commands. Note that inhibiting automatic line breaks may cause music to run over the right margin if it cannot all be contained within one line.

Automatic line breaks (but not page breaks) may be enabled at single bar lines by using \once \autoLineBreaksOn at a bar line. This identifies a permitted rather than a forced line break.

The most basic settings influencing line spacing are indent and line-width. They are set in the \layout block. They control the indentation of the first line of music, and the lengths of the lines.

If ragged-right is set to true in the \layout block, then systems end at their natural horizontal length, instead of being spread horizontally to fill the whole line. This is useful for short fragments, and for checking how tight the natural spacing is.

The option ragged-last is similar to ragged-right, but affects only the last line of the piece.

\layout {
  indent = 0\mm
  line-width = 150\mm
  ragged-last = ##t
}

For line breaks at regular intervals use \break separated by skips and repeated with \repeat. For example, this would cause the following 28 measures (assuming 4/4 time) to be broken every 4 measures, and only there:

<<
  \repeat unfold 7 {
    s1 \noBreak s1 \noBreak
    s1 \noBreak s1 \break
  }
  { the actual music… }
>>

Predefined commands

\break, \noBreak, \autoBreaksOff, \autoBreaksOn, \autoLineBreaksOff, \autoLineBreaksOn.

Selected Snippets

Using an extra voice for breaks

Often it is easier to manage line and page-breaking information by keeping it separate from the music by introducing an extra voice containing only skips along with the \break, pageBreak and other layout information.

This pattern becomes especially helpful when overriding line-break-system-details and the other useful but long properties of NonMusicalPaperColumnGrob.

music = \relative c'' { c4 c c c } \score { \new Staff << \new Voice { s1 * 2 \break s1 * 3 \break s1 * 6 \break s1 * 5 \break } \new Voice { \repeat unfold 2 { \music } \repeat unfold 3 { \music } \repeat unfold 6 { \music } \repeat unfold 5 { \music } } >> }

See also

Notation Reference: \paper variables for line breaking The \layout block.

Snippets: (snippets)Spacing section ‘Spacing’ in Snippets.

Internals Reference: (internals)LineBreakEvent section ‘LineBreakEvent’ in Internals Reference.

Known issues and warnings

Placing \autoLineBreaksOff or \autoBreaksOff before any music will cause error messages to appear. Always place these commands after some music.

4.3.2 Page breaking

This section describes the different page breaking methods, and how to modify them.

Manual page breaking

The default page breaking may be overridden by inserting \pageBreak or \noPageBreak commands. These commands are analogous to \break and \noBreak. They should be inserted at a bar line. These commands force and forbid a page-break from happening at that bar line. Of course, the \pageBreak command also forces a line break.

The \pageBreak and \noPageBreak commands may also be inserted at top-level, between scores and top-level markups.

Within a score, automatic page breaks are prevented within music lying between \autoPageBreaksOff and \autoPageBreaksOn commands. Manual page breaks are unaffected by these commands.

There are also analogous settings to ragged-right and ragged-last which have the same effect on vertical spacing. If ragged-bottom is set to #t the systems will not be justified vertically. When ragged-last-bottom is set to #t, as it is by default, empty space is allowed at the bottom of the final page (or the final page in each \bookpart). See Fixed vertical spacing \paper variables.

Page breaks are computed by the page-breaking function. LilyPond provides several algorithms for computing page breaks, including ly:optimal-breaking, ly:page-turn-breaking and ly:minimal-breaking. The default is ly:optimal-breaking, but the value can be changed in the \paper block:

\paper {
  page-breaking = #ly:page-turn-breaking
}

When a book has many scores and pages, the page breaking problem may be difficult to solve, requiring large processing time and memory. To ease the page breaking process, \bookpart blocks are used to divide the book into several parts: the page breaking occurs separately on each part. Different page breaking functions may also be used in different book parts.

\bookpart {
  \header {
    subtitle = "Preface"
  }
  \paper {
     %% In a part consisting mostly of text,
     %% ly:minimal-breaking may be preferred
     page-breaking = #ly:minimal-breaking
  }
  \markup { … }
  …
}
\bookpart {
  %% In this part, consisting of music, the default optimal
  %% page breaking function is used.
  \header {
    subtitle = "First movement"
  }
  \score { … }
  …
}

Predefined commands

\pageBreak, \noPageBreak, \autoPageBreaksOn, \autoPageBreaksOff.

See also

Notation Reference: \paper variables for page breaking.

Snippets: (snippets)Spacing section ‘Spacing’ in Snippets.

Known issues and warnings

The \once prefix is ineffective with \autoPageBreaksOn and \autoPageBreaksOff. If auto page breaking is off and is then turned on to permit a page break, it must remain on for a few bars (the precise number of bars depends on the score) before being turned off, else the opportunity to break the page will not be taken.

Optimal page breaking

The ly:optimal-breaking function is LilyPond’s default method of determining page breaks. It attempts to find a page breaking that minimizes cramping and stretching, both horizontally and vertically. Unlike ly:page-turn-breaking, it has no concept of page turns.

See also

Snippets: (snippets)Spacing section ‘Spacing’ in Snippets.

Minimal page breaking

The ly:minimal-breaking function performs minimal computations to calculate the page breaking: it fills a page with as many systems as possible before moving to the next one. Thus, it may be preferred for scores with many pages, where the other page breaking functions could be too slow or memory demanding, or a lot of texts. It is enabled using:

\paper {
  page-breaking = #ly:minimal-breaking
}

See also

Snippets: (snippets)Spacing section ‘Spacing’ in Snippets.

One-page page breaking

The ly:one-page-breaking function is a special-purpose page breaking algorithm that automatically adjusts the page height to fit the music, so that everything fits on a single page. The paper-height variable in the paper block is ignored, but other settings work as usual. In particular, the spacing between the last system (or top level markup) and the footer can be customized with last-bottom-spacing in the paper block. The width of the page is left unmodified by default but can be set with paper-width in the paper block.

Known issues and warnings

ly:one-page-breaking is not currently compatible with \bookpart.

One-line page breaking

The ly:one-line-breaking function is a special-purpose page breaking algorithm that puts each score on its own page, and on a single line. No titles or margins are typeset; only the score is displayed.

The page width is adjusted so that the longest score fits on one line. In particular, paper-width, line-width and indent variables in the \paper block are ignored, although left-margin and right-margin are still honored. The height of the page is left unmodified.

One-line-auto-height page breaking

The ly:one-line-auto-height-breaking function works just like ly:one-line-breaking except the page height is automatically modified to fit the height of the music. Specifically, the paper-height variable in the \paper block is set so that it spans the height of the tallest score plus the top-margin and bottom-margin.

Note that the top-system-spacing setting will affect the vertical position of the music. Set it to ##f in a paper block to simply place the music between the top and bottom margins.

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 (ly:make-moment 1/1). 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 = #(ly:make-moment 5/2)
  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: (snippets)Spacing section ‘Spacing’ in Snippets.

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: (snippets)Spacing section ‘Spacing’ in Snippets.

This document was generated by gub on July 13, 2020 using texi2html 1.82.

Más nyelvek: català, deutsch, español, français, italiano, 日本語.
Az automatikus nyelvválasztásról.