3.1.72 KeyCancellation (LilyPond Internals Reference)

#### 3.1.72 `KeyCancellation`

A key cancellation, normally consisting of naturals, to be displayed (if necessary) immediately before a `KeySignature` grob if the key changes.

`KeyCancellation` objects are created by the following engraver(s): `Key_engraver`.

Standard settings:

> `break-align-symbol` (symbol):

>   `'key-cancellation`

>   This key is used for aligning, ordering, and spacing breakable items. See break-alignment-interface.

> `break-visibility` (vector):

>       #(#t #t #f)

>   A vector of 3 booleans, `#(end-of-line unbroken begin-of-line)`. `#t` means visible, `#f` means killed.

> `extra-spacing-height` (pair of numbers):

>   `pure-from-neighbor-interface::extra-spacing-height-including-staff`

>   In the horizontal spacing problem, we increase the height of each item by this amount (by adding the ‘car’ to the bottom of the item and adding the ‘cdr’ to the top of the item). In order to make a grob infinitely high (to prevent the horizontal spacing problem from placing any other grobs above or below this grob), set this to `(-inf.0 . +inf.0)`.

> `extra-spacing-width` (pair of numbers):

>       '(0.0 . 1.0)

>   In the horizontal spacing problem, we pad each item by this amount (by adding the ‘car’ on the left side of the item and adding the ‘cdr’ on the right side of the item). In order to make a grob take up no horizontal space at all, set this to `(+inf.0 . -inf.0)`.

> `flat-positions` (list):

>       '(2 3 4 2 1 2 1)

>   Flats in key signatures are placed within the specified ranges of staff positions. The general form is a list of pairs, with one pair for each type of clef, in order of the staff position at which each clef places C: `(alto treble tenor soprano baritone mezzosoprano bass)`. If the list contains a single element it applies for all clefs. A single number in place of a pair sets accidentals within the octave ending at that staff position.

> `non-musical` (boolean):

>   `#t`

>   True if the grob belongs to a `NonMusicalPaperColumn`.

> `sharp-positions` (list):

>       '(4 5 4 2 3 2 3)

>   Sharps in key signatures are placed within the specified ranges of staff positions. The general form is a list of pairs, with one pair for each type of clef, in order of the staff position at which each clef places C: `(alto treble tenor soprano baritone mezzosoprano bass)`. If the list contains a single element it applies for all clefs. A single number in place of a pair sets accidentals within the octave ending at that staff position.

> `space-alist` (alist, with symbols as keys):

>       '((time-signature extra-space . 1.25)
>         (signum-repetitionis extra-space . 0.6)
>         (staff-bar extra-space . 0.6)
>         (key-signature extra-space . 0.5)
>         (cue-clef extra-space . 0.5)
>         (right-edge extra-space . 0.5)
>         (first-note shrink-space . 2.5)
>         (optional-material-end-bracket extra-space . 1.0)
>         (optional-material-start-bracket
>           extra-space
>           .
>           1.0)
>         (custos extra-space . 1.0))

>   An alist that specifies distances from this grob to other breakable items, using the format:

>       '((break-align-symbol . (spacing-style . space))
>         (break-align-symbol . (spacing-style . space))
>         ...)

>   Standard choices for `break-align-symbol` are listed in Grobs and their break-align symbols. Additionally, three special break-align symbols available to `space-alist` are:

>   > `first-note`

>   >   used when the grob is just left of the first note on a line

>   > `next-note`

>   >   used when the grob is just left of any other note; if not set, the value of `first-note` gets used

>   > `right-edge`

>   >   used when the grob is the last item on the line (only compatible with the `extra-space` spacing style)

>   If `space-alist` is defined for a grob that gets spaced in a staff, an entry for `first-note` must be present. If there is no `next-note` entry, the value of `first-note` is used instead.

>   Choices for `spacing-style` are:

>   > `extra-space`

>   >   Put this much space between the two grobs. The space is stretchable and shrinkable when paired with `first-note` or `next-note`; otherwise it is fixed.

>   > `minimum-space`

>   >   Put at least this much space between the left sides of both grobs, without allowing them to collide. The space is stretchable and shrinkable when paired with `first-note` or `next-note`; otherwise it is fixed. Not compatible with `right-edge`.

>   > `fixed-space`

>   >   Only compatible with `first-note` and `next-note`. Put this much fixed space between the grob and the note.

>   > `minimum-fixed-space`

>   >   Only compatible with `first-note` and `next-note`. Put at least this much fixed space between the left side of the grob and the left side of the note, without allowing them to collide.

>   > `semi-fixed-space`

>   >   Only compatible with `first-note` and `next-note`. Put this much space between the grob and the note, such that half of the space is fixed and half is stretchable and shrinkable.

>   > `shrink-space`

>   >   Only compatible with `first-note` and `next-note`. Put this much space between the two grobs. The space is only shrinkable.

>   > `semi-shrink-space`

>   >   Only compatible with `first-note` and `next-note`. Put this much space between the grob and the note, such that half of the space is fixed and half is shrinkable.

>   Rules for this spacing are much more complicated than this. See [Wanske] page 126–134, [Ross] page 143–147.

> `stencil` (stencil):

>   `ly:key-signature-interface::print`

>   The symbol to print.

> `vertical-skylines` (pair of skylines):

>   `#<unpure-pure-container ly:grob::vertical-skylines-from-stencil >`

>   Two skylines, one above and one below this grob.

> `Y-extent` (pair of numbers):

>   `#<unpure-pure-container ly:grob::stencil-height >`

>   Extent (size) in the Y direction, measured in staff-space units, relative to object’s reference point.

> `Y-offset` (number):

>   `#<unpure-pure-container ly:staff-symbol-referencer::callback >`

>   The vertical amount that this object is moved relative to its Y-parent.

>   Note that many objects have special positioning considerations, which cause any setting of `Y-offset` to be ignored or modified, even though the object supports the `self-alignment-interface`.

This object supports the following interface(s): `accidental-switch-interface`, `break-aligned-interface`, `font-interface`, `grob-interface`, `item-interface`, `key-cancellation-interface`, `key-signature-interface`, `pure-from-neighbor-interface` and `staff-symbol-referencer-interface`.

This object is of class Item (characterized by `item-interface`).

#### LilyPond Internals Reference v2.26.0 (stable-branch).

- 1 Music definitions
  - 1.1 Music expressions
    - 1.1.1 `AbsoluteDynamicEvent`
    - 1.1.2 `AdHocJumpEvent`
    - 1.1.3 `AdHocMarkEvent`
    - 1.1.4 `AlternativeEvent`
    - 1.1.5 `AnnotateOutputEvent`
    - 1.1.6 `ApplyContext`
    - 1.1.7 `ApplyOutputEvent`
    - 1.1.8 `ArpeggioEvent`
    - 1.1.9 `ArticulationEvent`
    - 1.1.10 `BarCheckEvent`
    - 1.1.11 `BarEvent`
    - 1.1.12 `BassFigureEvent`
    - 1.1.13 `BeamEvent`
    - 1.1.14 `BeamForbidEvent`
    - 1.1.15 `BendAfterEvent`
    - 1.1.16 `BendSpanEvent`
    - 1.1.17 `BreakDynamicSpanEvent`
    - 1.1.18 `BreathingEvent`
    - 1.1.19 `CaesuraEvent`
    - 1.1.20 `ChordSlurEvent`
    - 1.1.21 `ClusterNoteEvent`
    - 1.1.22 `CodaMarkEvent`
    - 1.1.23 `CompletizeExtenderEvent`
    - 1.1.24 `ContextChange`
    - 1.1.25 `ContextSpeccedMusic`
    - 1.1.26 `CrescendoEvent`
    - 1.1.27 `DalSegnoEvent`
    - 1.1.28 `DecrescendoEvent`
    - 1.1.29 `DoublePercentEvent`
    - 1.1.30 `DurationLineEvent`
    - 1.1.31 `EpisemaEvent`
    - 1.1.32 `Event`
    - 1.1.33 `EventChord`
    - 1.1.34 `ExtenderEvent`
    - 1.1.35 `FineEvent`
    - 1.1.36 `FingerGlideEvent`
    - 1.1.37 `FingeringEvent`
    - 1.1.38 `FootnoteEvent`
    - 1.1.39 `GlissandoEvent`
    - 1.1.40 `GraceMusic`
    - 1.1.41 `HarmonicEvent`
    - 1.1.42 `HyphenEvent`
    - 1.1.43 `InitialContextMusic`
    - 1.1.44 `KeyChangeEvent`
    - 1.1.45 `LabelEvent`
    - 1.1.46 `LaissezVibrerEvent`
    - 1.1.47 `LigatureEvent`
    - 1.1.48 `LineBreakEvent`
    - 1.1.49 `LyricCombineMusic`
    - 1.1.50 `LyricEvent`
    - 1.1.51 `MeasureCounterEvent`
    - 1.1.52 `MeasureSpannerEvent`
    - 1.1.53 `MultiMeasureArticulationEvent`
    - 1.1.54 `MultiMeasureRestEvent`
    - 1.1.55 `MultiMeasureRestMusic`
    - 1.1.56 `MultiMeasureTextEvent`
    - 1.1.57 `Music`
    - 1.1.58 `NonArpeggiatoEvent`
    - 1.1.59 `NoteEvent`
    - 1.1.60 `NoteGroupingEvent`
    - 1.1.61 `OptionalMaterialEvent`
    - 1.1.62 `OttavaEvent`
    - 1.1.63 `OverrideProperty`
    - 1.1.64 `PageBreakEvent`
    - 1.1.65 `PageTurnEvent`
    - 1.1.66 `PartCombineEvent`
    - 1.1.67 `PartCombineMusic`
    - 1.1.68 `PartialEvent`
    - 1.1.69 `PartialSet`
    - 1.1.70 `PercentEvent`
    - 1.1.71 `PercentRepeatedMusic`
    - 1.1.72 `PesOrFlexaEvent`
    - 1.1.73 `PhrasingSlurEvent`
    - 1.1.74 `PolymetricTimeSignatureEvent`
    - 1.1.75 `PolymetricTimeSignatureMusic`
    - 1.1.76 `PostEvents`
    - 1.1.77 `PropertySet`
    - 1.1.78 `PropertyUnset`
    - 1.1.79 `QuoteMusic`
    - 1.1.80 `ReferenceTimeSignatureEvent`
    - 1.1.81 `ReferenceTimeSignatureMusic`
    - 1.1.82 `RehearsalMarkEvent`
    - 1.1.83 `RelativeOctaveCheck`
    - 1.1.84 `RelativeOctaveMusic`
    - 1.1.85 `RepeatSlashEvent`
    - 1.1.86 `RepeatTieEvent`
    - 1.1.87 `RestEvent`
    - 1.1.88 `RevertProperty`
    - 1.1.89 `ScriptEvent`
    - 1.1.90 `SectionEvent`
    - 1.1.91 `SectionLabelEvent`
    - 1.1.92 `SegnoMarkEvent`
    - 1.1.93 `SegnoRepeatedMusic`
    - 1.1.94 `SequentialAlternativeMusic`
    - 1.1.95 `SequentialMusic`
    - 1.1.96 `SimultaneousMusic`
    - 1.1.97 `SkipEvent`
    - 1.1.98 `SkipMusic`
    - 1.1.99 `SkippedMusic`
    - 1.1.100 `SlurEvent`
    - 1.1.101 `SostenutoEvent`
    - 1.1.102 `SpacingSectionEvent`
    - 1.1.103 `SpanEvent`
    - 1.1.104 `StaffHighlightEvent`
    - 1.1.105 `StaffSpanEvent`
    - 1.1.106 `StringNumberEvent`
    - 1.1.107 `StrokeFingerEvent`
    - 1.1.108 `SustainEvent`
    - 1.1.109 `TempoChangeEvent`
    - 1.1.110 `TextMarkEvent`
    - 1.1.111 `TextScriptEvent`
    - 1.1.112 `TextSpanEvent`
    - 1.1.113 `TieEvent`
    - 1.1.114 `TimeScaledMusic`
    - 1.1.115 `TransposedMusic`
    - 1.1.116 `TremoloEvent`
    - 1.1.117 `TremoloRepeatedMusic`
    - 1.1.118 `TremoloSpanEvent`
    - 1.1.119 `TrillSpanEvent`
    - 1.1.120 `TupletSpanEvent`
    - 1.1.121 `UnaCordaEvent`
    - 1.1.122 `UnfoldedRepeatedMusic`
    - 1.1.123 `UnfoldedSpeccedMusic`
    - 1.1.124 `UnrelativableMusic`
    - 1.1.125 `VoiceSeparator`
    - 1.1.126 `VoltaRepeatEndEvent`
    - 1.1.127 `VoltaRepeatStartEvent`
    - 1.1.128 `VoltaRepeatedMusic`
    - 1.1.129 `VoltaSpanEvent`
    - 1.1.130 `VoltaSpeccedMusic`
    - 1.1.131 `VowelTransitionEvent`
  - 1.2 Music classes
    - 1.2.1 `absolute-dynamic-event`
    - 1.2.2 `ad-hoc-jump-event`
    - 1.2.3 `ad-hoc-mark-event`
    - 1.2.4 `alternative-event`
    - 1.2.5 `annotate-output-event`
    - 1.2.6 `apply-output-event`
    - 1.2.7 `arpeggio-event`
    - 1.2.8 `articulation-event`
    - 1.2.9 `bar-check-event`
    - 1.2.10 `bar-event`
    - 1.2.11 `bass-figure-event`
    - 1.2.12 `beam-event`
    - 1.2.13 `beam-forbid-event`
    - 1.2.14 `bend-after-event`
    - 1.2.15 `bend-span-event`
    - 1.2.16 `break-dynamic-span-event`
    - 1.2.17 `break-event`
    - 1.2.18 `break-span-event`
    - 1.2.19 `breathing-event`
    - 1.2.20 `caesura-event`
    - 1.2.21 `chord-slur-event`
    - 1.2.22 `cluster-note-event`
    - 1.2.23 `coda-mark-event`
    - 1.2.24 `completize-extender-event`
    - 1.2.25 `crescendo-event`
    - 1.2.26 `dal-segno-event`
    - 1.2.27 `decrescendo-event`
    - 1.2.28 `double-percent-event`
    - 1.2.29 `duration-line-event`
    - 1.2.30 `dynamic-event`
    - 1.2.31 `episema-event`
    - 1.2.32 `extender-event`
    - 1.2.33 `fine-event`
    - 1.2.34 `finger-glide-event`
    - 1.2.35 `fingering-event`
    - 1.2.36 `footnote-event`
    - 1.2.37 `general-rest-event`
    - 1.2.38 `glissando-event`
    - 1.2.39 `harmonic-event`
    - 1.2.40 `hyphen-event`
    - 1.2.41 `key-change-event`
    - 1.2.42 `label-event`
    - 1.2.43 `laissez-vibrer-event`
    - 1.2.44 `layout-instruction-event`
    - 1.2.45 `ligature-event`
    - 1.2.46 `line-break-event`
    - 1.2.47 `lyric-event`
    - 1.2.48 `mark-event`
    - 1.2.49 `measure-counter-event`
    - 1.2.50 `measure-spanner-event`
    - 1.2.51 `melodic-event`
    - 1.2.52 `multi-measure-articulation-event`
    - 1.2.53 `multi-measure-rest-event`
    - 1.2.54 `multi-measure-text-event`
    - 1.2.55 `music-event`
    - 1.2.56 `non-arpeggiato-event`
    - 1.2.57 `note-event`
    - 1.2.58 `note-grouping-event`
    - 1.2.59 `optional-material-event`
    - 1.2.60 `ottava-event`
    - 1.2.61 `page-break-event`
    - 1.2.62 `page-turn-event`
    - 1.2.63 `part-combine-event`
    - 1.2.64 `partial-event`
    - 1.2.65 `pedal-event`
    - 1.2.66 `percent-event`
    - 1.2.67 `pes-or-flexa-event`
    - 1.2.68 `phrasing-slur-event`
    - 1.2.69 `polymetric-time-signature-event`
    - 1.2.70 `reference-time-signature-event`
    - 1.2.71 `rehearsal-mark-event`
    - 1.2.72 `repeat-slash-event`
    - 1.2.73 `repeat-tie-event`
    - 1.2.74 `rest-event`
    - 1.2.75 `rhythmic-event`
    - 1.2.76 `script-event`
    - 1.2.77 `section-event`
    - 1.2.78 `section-label-event`
    - 1.2.79 `segno-mark-event`
    - 1.2.80 `skip-event`
    - 1.2.81 `slur-event`
    - 1.2.82 `sostenuto-event`
    - 1.2.83 `spacing-section-event`
    - 1.2.84 `span-dynamic-event`
    - 1.2.85 `span-event`
    - 1.2.86 `staff-highlight-event`
    - 1.2.87 `staff-span-event`
    - 1.2.88 `StreamEvent`
    - 1.2.89 `string-number-event`
    - 1.2.90 `stroke-finger-event`
    - 1.2.91 `structural-event`
    - 1.2.92 `sustain-event`
    - 1.2.93 `tempo-change-event`
    - 1.2.94 `text-mark-event`
    - 1.2.95 `text-script-event`
    - 1.2.96 `text-span-event`
    - 1.2.97 `tie-event`
    - 1.2.98 `time-signature-event`
    - 1.2.99 `tremolo-event`
    - 1.2.100 `tremolo-span-event`
    - 1.2.101 `trill-span-event`
    - 1.2.102 `tuplet-span-event`
    - 1.2.103 `una-corda-event`
    - 1.2.104 `volta-repeat-end-event`
    - 1.2.105 `volta-repeat-start-event`
    - 1.2.106 `volta-span-event`
    - 1.2.107 `vowel-transition-event`
  - 1.3 Music properties
- 2 Translation
  - 2.1 Contexts
    - 2.1.1 `ChoirStaff`
    - 2.1.2 `ChordGrid`
    - 2.1.3 `ChordGridScore`
    - 2.1.4 `ChordNames`
    - 2.1.5 `CueVoice`
    - 2.1.6 `Devnull`
    - 2.1.7 `DrumStaff`
    - 2.1.8 `DrumVoice`
    - 2.1.9 `Dynamics`
    - 2.1.10 `FiguredBass`
    - 2.1.11 `FretBoards`
    - 2.1.12 `Global`
    - 2.1.13 `GrandStaff`
    - 2.1.14 `GregorianTranscriptionLyrics`
    - 2.1.15 `GregorianTranscriptionStaff`
    - 2.1.16 `GregorianTranscriptionVoice`
    - 2.1.17 `InternalGregorianStaff`
    - 2.1.18 `InternalMensuralStaff`
    - 2.1.19 `KievanStaff`
    - 2.1.20 `KievanVoice`
    - 2.1.21 `Lyrics`
    - 2.1.22 `MensuralStaff`
    - 2.1.23 `MensuralVoice`
    - 2.1.24 `NoteNames`
    - 2.1.25 `NullVoice`
    - 2.1.26 `OneStaff`
    - 2.1.27 `PetrucciStaff`
    - 2.1.28 `PetrucciVoice`
    - 2.1.29 `PianoStaff`
    - 2.1.30 `RhythmicStaff`
    - 2.1.31 `Score`
    - 2.1.32 `Staff`
    - 2.1.33 `StaffGroup`
    - 2.1.34 `StandaloneRhythmScore`
    - 2.1.35 `StandaloneRhythmStaff`
    - 2.1.36 `StandaloneRhythmVoice`
    - 2.1.37 `TabStaff`
    - 2.1.38 `TabVoice`
    - 2.1.39 `VaticanaLyrics`
    - 2.1.40 `VaticanaScore`
    - 2.1.41 `VaticanaStaff`
    - 2.1.42 `VaticanaVoice`
    - 2.1.43 `Voice`
  - 2.2 Engravers and Performers
    - 2.2.1 `Accidental_engraver`
    - 2.2.2 `Alteration_glyph_engraver`
    - 2.2.3 `Ambitus_engraver`
    - 2.2.4 `Apply_output_engraver`
    - 2.2.5 `Arpeggio_engraver`
    - 2.2.6 `Auto_beam_engraver`
    - 2.2.7 `Axis_group_engraver`
    - 2.2.8 `Balloon_engraver`
    - 2.2.9 `Bar_engraver`
    - 2.2.10 `Bar_number_engraver`
    - 2.2.11 `Beam_collision_engraver`
    - 2.2.12 `Beam_engraver`
    - 2.2.13 `Beam_performer`
    - 2.2.14 `Beat_engraver`
    - 2.2.15 `Beat_performer`
    - 2.2.16 `Bend_engraver`
    - 2.2.17 `Bend_spanner_engraver`
    - 2.2.18 `Break_align_engraver`
    - 2.2.19 `Breathing_sign_engraver`
    - 2.2.20 `Caesura_engraver`
    - 2.2.21 `Centered_bar_number_align_engraver`
    - 2.2.22 `Chord_name_engraver`
    - 2.2.23 `Chord_square_engraver`
    - 2.2.24 `Chord_tremolo_engraver`
    - 2.2.25 `Clef_engraver`
    - 2.2.26 `Cluster_spanner_engraver`
    - 2.2.27 `Collision_engraver`
    - 2.2.28 `Completion_heads_engraver`
    - 2.2.29 `Completion_rest_engraver`
    - 2.2.30 `Concurrent_hairpin_engraver`
    - 2.2.31 `Control_track_performer`
    - 2.2.32 `Cue_clef_engraver`
    - 2.2.33 `Current_chord_text_engraver`
    - 2.2.34 `Custos_engraver`
    - 2.2.35 `Divisio_engraver`
    - 2.2.36 `Dot_column_engraver`
    - 2.2.37 `Dots_engraver`
    - 2.2.38 `Double_percent_repeat_engraver`
    - 2.2.39 `Drum_note_performer`
    - 2.2.40 `Drum_notes_engraver`
    - 2.2.41 `Duration_line_engraver`
    - 2.2.42 `Dynamic_align_engraver`
    - 2.2.43 `Dynamic_engraver`
    - 2.2.44 `Dynamic_performer`
    - 2.2.45 `Episema_engraver`
    - 2.2.46 `Extender_engraver`
    - 2.2.47 `Figured_bass_engraver`
    - 2.2.48 `Figured_bass_position_engraver`
    - 2.2.49 `Finger_glide_engraver`
    - 2.2.50 `Fingering_column_engraver`
    - 2.2.51 `Fingering_engraver`
    - 2.2.52 `Font_size_engraver`
    - 2.2.53 `Footnote_engraver`
    - 2.2.54 `Forbid_line_break_engraver`
    - 2.2.55 `Fretboard_engraver`
    - 2.2.56 `Glissando_engraver`
    - 2.2.57 `Grace_auto_beam_engraver`
    - 2.2.58 `Grace_beam_engraver`
    - 2.2.59 `Grace_engraver`
    - 2.2.60 `Grace_spacing_engraver`
    - 2.2.61 `Grid_chord_name_engraver`
    - 2.2.62 `Grid_line_span_engraver`
    - 2.2.63 `Grid_point_engraver`
    - 2.2.64 `Grob_pq_engraver`
    - 2.2.65 `Horizontal_bracket_engraver`
    - 2.2.66 `Horizontal_script_engraver`
    - 2.2.67 `Hyphen_engraver`
    - 2.2.68 `Instrument_name_engraver`
    - 2.2.69 `Instrument_switch_engraver`
    - 2.2.70 `Jump_engraver`
    - 2.2.71 `Keep_alive_together_engraver`
    - 2.2.72 `Key_engraver`
    - 2.2.73 `Key_performer`
    - 2.2.74 `Kievan_ligature_engraver`
    - 2.2.75 `Laissez_vibrer_engraver`
    - 2.2.76 `Ledger_line_engraver`
    - 2.2.77 `Ligature_bracket_engraver`
    - 2.2.78 `Lyric_engraver`
    - 2.2.79 `Lyric_performer`
    - 2.2.80 `Lyric_repeat_count_engraver`
    - 2.2.81 `Mark_engraver`
    - 2.2.82 `Mark_performer`
    - 2.2.83 `Mark_tracking_translator`
    - 2.2.84 `Measure_counter_engraver`
    - 2.2.85 `Measure_grouping_engraver`
    - 2.2.86 `Measure_spanner_engraver`
    - 2.2.87 `Melody_engraver`
    - 2.2.88 `Mensural_ligature_engraver`
    - 2.2.89 `Merge_mmrest_numbers_engraver`
    - 2.2.90 `Merge_rests_engraver`
    - 2.2.91 `Metronome_mark_engraver`
    - 2.2.92 `Midi_control_change_performer`
    - 2.2.93 `Multi_measure_rest_engraver`
    - 2.2.94 `New_fingering_engraver`
    - 2.2.95 `Non_musical_script_column_engraver`
    - 2.2.96 `Note_head_line_engraver`
    - 2.2.97 `Note_heads_engraver`
    - 2.2.98 `Note_name_engraver`
    - 2.2.99 `Note_performer`
    - 2.2.100 `Note_spacing_engraver`
    - 2.2.101 `Optional_material_bracket_engraver`
    - 2.2.102 `Ottava_spanner_engraver`
    - 2.2.103 `Page_turn_engraver`
    - 2.2.104 `Paper_column_engraver`
    - 2.2.105 `Parenthesis_engraver`
    - 2.2.106 `Part_combine_engraver`
    - 2.2.107 `Percent_repeat_engraver`
    - 2.2.108 `Phrasing_slur_engraver`
    - 2.2.109 `Piano_pedal_align_engraver`
    - 2.2.110 `Piano_pedal_engraver`
    - 2.2.111 `Piano_pedal_performer`
    - 2.2.112 `Pitch_squash_engraver`
    - 2.2.113 `Pitched_trill_engraver`
    - 2.2.114 `Pure_from_neighbor_engraver`
    - 2.2.115 `Repeat_acknowledge_engraver`
    - 2.2.116 `Repeat_tie_engraver`
    - 2.2.117 `Rest_collision_engraver`
    - 2.2.118 `Rest_engraver`
    - 2.2.119 `Rhythmic_column_engraver`
    - 2.2.120 `Script_column_engraver`
    - 2.2.121 `Script_engraver`
    - 2.2.122 `Script_row_engraver`
    - 2.2.123 `Separating_line_group_engraver`
    - 2.2.124 `Show_control_points_engraver`
    - 2.2.125 `Signum_repetitionis_engraver`
    - 2.2.126 `Skip_typesetting_engraver`
    - 2.2.127 `Slash_repeat_engraver`
    - 2.2.128 `Slur_engraver`
    - 2.2.129 `Slur_performer`
    - 2.2.130 `Spacing_engraver`
    - 2.2.131 `Span_arpeggio_engraver`
    - 2.2.132 `Span_bar_engraver`
    - 2.2.133 `Span_bar_stub_engraver`
    - 2.2.134 `Span_stem_engraver`
    - 2.2.135 `Spanner_break_forbid_engraver`
    - 2.2.136 `Spanner_tracking_engraver`
    - 2.2.137 `Staff_collecting_engraver`
    - 2.2.138 `Staff_highlight_engraver`
    - 2.2.139 `Staff_performer`
    - 2.2.140 `Staff_symbol_engraver`
    - 2.2.141 `Stanza_number_align_engraver`
    - 2.2.142 `Stanza_number_engraver`
    - 2.2.143 `Stem_engraver`
    - 2.2.144 `System_start_delimiter_engraver`
    - 2.2.145 `Tab_note_heads_engraver`
    - 2.2.146 `Tab_staff_symbol_engraver`
    - 2.2.147 `Tab_tie_follow_engraver`
    - 2.2.148 `Tempo_performer`
    - 2.2.149 `Text_engraver`
    - 2.2.150 `Text_mark_engraver`
    - 2.2.151 `Text_spanner_engraver`
    - 2.2.152 `Tie_engraver`
    - 2.2.153 `Tie_performer`
    - 2.2.154 `Time_signature_engraver`
    - 2.2.155 `Time_signature_performer`
    - 2.2.156 `Timing_translator`
    - 2.2.157 `Toe_heel_engraver`
    - 2.2.158 `Trill_spanner_engraver`
    - 2.2.159 `Tuplet_engraver`
    - 2.2.160 `Tweak_engraver`
    - 2.2.161 `Vaticana_ligature_engraver`
    - 2.2.162 `Vertical_align_engraver`
    - 2.2.163 `Volta_engraver`
  - 2.3 Tunable context properties
  - 2.4 Internal context properties
- 3 Backend
  - 3.1 All layout objects
    - 3.1.1 `Accidental`
    - 3.1.2 `AccidentalCautionary`
    - 3.1.3 `AccidentalPlacement`
    - 3.1.4 `AccidentalSuggestion`
    - 3.1.5 `Ambitus`
    - 3.1.6 `AmbitusAccidental`
    - 3.1.7 `AmbitusLine`
    - 3.1.8 `AmbitusNoteHead`
    - 3.1.9 `ApproximatePitchNoteHead`
    - 3.1.10 `Arpeggio`
    - 3.1.11 `BalloonText`
    - 3.1.12 `BarLine`
    - 3.1.13 `BarNumber`
    - 3.1.14 `BassFigure`
    - 3.1.15 `BassFigureAlignment`
    - 3.1.16 `BassFigureAlignmentPositioning`
    - 3.1.17 `BassFigureBracket`
    - 3.1.18 `BassFigureContinuation`
    - 3.1.19 `BassFigureLine`
    - 3.1.20 `Beam`
    - 3.1.21 `BendAfter`
    - 3.1.22 `BendSpanner`
    - 3.1.23 `BreakAlignGroup`
    - 3.1.24 `BreakAlignment`
    - 3.1.25 `BreathingSign`
    - 3.1.26 `CaesuraScript`
    - 3.1.27 `CenteredBarNumber`
    - 3.1.28 `CenteredBarNumberLineSpanner`
    - 3.1.29 `ChordBracket`
    - 3.1.30 `ChordName`
    - 3.1.31 `ChordSlur`
    - 3.1.32 `ChordSquare`
    - 3.1.33 `Clef`
    - 3.1.34 `ClefModifier`
    - 3.1.35 `ClusterSpanner`
    - 3.1.36 `ClusterSpannerBeacon`
    - 3.1.37 `CodaMark`
    - 3.1.38 `CombineTextScript`
    - 3.1.39 `ControlPoint`
    - 3.1.40 `ControlPolygon`
    - 3.1.41 `CueClef`
    - 3.1.42 `CueEndClef`
    - 3.1.43 `Custos`
    - 3.1.44 `Divisio`
    - 3.1.45 `DotColumn`
    - 3.1.46 `Dots`
    - 3.1.47 `DoublePercentRepeat`
    - 3.1.48 `DoublePercentRepeatCounter`
    - 3.1.49 `DoubleRepeatSlash`
    - 3.1.50 `DurationLine`
    - 3.1.51 `DynamicLineSpanner`
    - 3.1.52 `DynamicText`
    - 3.1.53 `DynamicTextSpanner`
    - 3.1.54 `Episema`
    - 3.1.55 `FingerGlideSpanner`
    - 3.1.56 `Fingering`
    - 3.1.57 `FingeringColumn`
    - 3.1.58 `Flag`
    - 3.1.59 `Footnote`
    - 3.1.60 `FretBoard`
    - 3.1.61 `Glissando`
    - 3.1.62 `GraceSpacing`
    - 3.1.63 `GridChordName`
    - 3.1.64 `GridLine`
    - 3.1.65 `GridPoint`
    - 3.1.66 `Hairpin`
    - 3.1.67 `HorizontalBracket`
    - 3.1.68 `HorizontalBracketText`
    - 3.1.69 `InstrumentName`
    - 3.1.70 `InstrumentSwitch`
    - 3.1.71 `JumpScript`
    - 3.1.72 `KeyCancellation`
    - 3.1.73 `KeySignature`
    - 3.1.74 `KievanLigature`
    - 3.1.75 `LaissezVibrerTie`
    - 3.1.76 `LaissezVibrerTieColumn`
    - 3.1.77 `LedgerLineSpanner`
    - 3.1.78 `LeftEdge`
    - 3.1.79 `LigatureBracket`
    - 3.1.80 `LyricExtender`
    - 3.1.81 `LyricHyphen`
    - 3.1.82 `LyricRepeatCount`
    - 3.1.83 `LyricSpace`
    - 3.1.84 `LyricText`
    - 3.1.85 `MeasureCounter`
    - 3.1.86 `MeasureGrouping`
    - 3.1.87 `MeasureSpanner`
    - 3.1.88 `MelodyItem`
    - 3.1.89 `MensuralLigature`
    - 3.1.90 `MetronomeMark`
    - 3.1.91 `MultiMeasureRest`
    - 3.1.92 `MultiMeasureRestNumber`
    - 3.1.93 `MultiMeasureRestScript`
    - 3.1.94 `MultiMeasureRestText`
    - 3.1.95 `NonMusicalPaperColumn`
    - 3.1.96 `NoteCollision`
    - 3.1.97 `NoteColumn`
    - 3.1.98 `NoteHead`
    - 3.1.99 `NoteName`
    - 3.1.100 `NoteSpacing`
    - 3.1.101 `OptionalMaterialBracket`
    - 3.1.102 `OttavaBracket`
    - 3.1.103 `PaperColumn`
    - 3.1.104 `Parentheses`
    - 3.1.105 `PercentRepeat`
    - 3.1.106 `PercentRepeatCounter`
    - 3.1.107 `PhrasingSlur`
    - 3.1.108 `PianoPedalBracket`
    - 3.1.109 `RehearsalMark`
    - 3.1.110 `RepeatSlash`
    - 3.1.111 `RepeatTie`
    - 3.1.112 `RepeatTieColumn`
    - 3.1.113 `Rest`
    - 3.1.114 `RestCollision`
    - 3.1.115 `Script`
    - 3.1.116 `ScriptColumn`
    - 3.1.117 `ScriptRow`
    - 3.1.118 `SectionLabel`
    - 3.1.119 `SegnoMark`
    - 3.1.120 `SignumRepetitionis`
    - 3.1.121 `Slur`
    - 3.1.122 `SostenutoPedal`
    - 3.1.123 `SostenutoPedalLineSpanner`
    - 3.1.124 `SpacingSpanner`
    - 3.1.125 `SpanBar`
    - 3.1.126 `SpanBarStub`
    - 3.1.127 `StaffEllipsis`
    - 3.1.128 `StaffGrouper`
    - 3.1.129 `StaffHighlight`
    - 3.1.130 `StaffSpacing`
    - 3.1.131 `StaffSymbol`
    - 3.1.132 `StanzaNumber`
    - 3.1.133 `Stem`
    - 3.1.134 `StemStub`
    - 3.1.135 `StemTremolo`
    - 3.1.136 `StringNumber`
    - 3.1.137 `StrokeFinger`
    - 3.1.138 `SustainPedal`
    - 3.1.139 `SustainPedalLineSpanner`
    - 3.1.140 `System`
    - 3.1.141 `SystemStartBar`
    - 3.1.142 `SystemStartBrace`
    - 3.1.143 `SystemStartBracket`
    - 3.1.144 `SystemStartSquare`
    - 3.1.145 `TabNoteHead`
    - 3.1.146 `TextMark`
    - 3.1.147 `TextScript`
    - 3.1.148 `TextSpanner`
    - 3.1.149 `Tie`
    - 3.1.150 `TieColumn`
    - 3.1.151 `TimeSignature`
    - 3.1.152 `TrillPitchAccidental`
    - 3.1.153 `TrillPitchGroup`
    - 3.1.154 `TrillPitchHead`
    - 3.1.155 `TrillPitchParentheses`
    - 3.1.156 `TrillSpanner`
    - 3.1.157 `TupletBracket`
    - 3.1.158 `TupletNumber`
    - 3.1.159 `UnaCordaPedal`
    - 3.1.160 `UnaCordaPedalLineSpanner`
    - 3.1.161 `VaticanaLigature`
    - 3.1.162 `VerticalAlignment`
    - 3.1.163 `VerticalAxisGroup`
    - 3.1.164 `VoiceFollower`
    - 3.1.165 `VoltaBracket`
    - 3.1.166 `VoltaBracketSpanner`
    - 3.1.167 `VowelTransition`
  - 3.2 Graphical Object Interfaces
    - 3.2.1 `accidental-interface`
    - 3.2.2 `accidental-participating-head-interface`
    - 3.2.3 `accidental-placement-interface`
    - 3.2.4 `accidental-suggestion-interface`
    - 3.2.5 `accidental-switch-interface`
    - 3.2.6 `align-interface`
    - 3.2.7 `ambitus-interface`
    - 3.2.8 `arpeggio-interface`
    - 3.2.9 `axis-group-interface`
    - 3.2.10 `balloon-interface`
    - 3.2.11 `bar-line-interface`
    - 3.2.12 `bar-number-interface`
    - 3.2.13 `bass-figure-alignment-interface`
    - 3.2.14 `bass-figure-interface`
    - 3.2.15 `beam-interface`
    - 3.2.16 `bend-after-interface`
    - 3.2.17 `bend-interface`
    - 3.2.18 `bezier-curve-interface`
    - 3.2.19 `break-alignable-interface`
    - 3.2.20 `break-aligned-interface`
    - 3.2.21 `break-alignment-interface`
    - 3.2.22 `breathing-sign-interface`
    - 3.2.23 `caesura-script-interface`
    - 3.2.24 `centered-bar-number-interface`
    - 3.2.25 `centered-bar-number-line-spanner-interface`
    - 3.2.26 `centered-spanner-interface`
    - 3.2.27 `chord-bracket-interface`
    - 3.2.28 `chord-name-interface`
    - 3.2.29 `chord-slur-interface`
    - 3.2.30 `chord-square-interface`
    - 3.2.31 `clef-interface`
    - 3.2.32 `clef-modifier-interface`
    - 3.2.33 `cluster-beacon-interface`
    - 3.2.34 `cluster-interface`
    - 3.2.35 `coda-mark-interface`
    - 3.2.36 `control-point-interface`
    - 3.2.37 `control-polygon-interface`
    - 3.2.38 `custos-interface`
    - 3.2.39 `dot-column-interface`
    - 3.2.40 `dots-interface`
    - 3.2.41 `duration-line-interface`
    - 3.2.42 `dynamic-interface`
    - 3.2.43 `dynamic-line-spanner-interface`
    - 3.2.44 `dynamic-text-interface`
    - 3.2.45 `dynamic-text-spanner-interface`
    - 3.2.46 `enclosing-bracket-interface`
    - 3.2.47 `episema-interface`
    - 3.2.48 `figured-bass-continuation-interface`
    - 3.2.49 `finger-glide-interface`
    - 3.2.50 `finger-interface`
    - 3.2.51 `fingering-column-interface`
    - 3.2.52 `flag-interface`
    - 3.2.53 `font-interface`
    - 3.2.54 `footnote-interface`
    - 3.2.55 `fret-diagram-interface`
    - 3.2.56 `glissando-interface`
    - 3.2.57 `grace-spacing-interface`
    - 3.2.58 `gregorian-ligature-interface`
    - 3.2.59 `grid-chord-name-interface`
    - 3.2.60 `grid-line-interface`
    - 3.2.61 `grid-point-interface`
    - 3.2.62 `grob-interface`
    - 3.2.63 `hairpin-interface`
    - 3.2.64 `hara-kiri-group-spanner-interface`
    - 3.2.65 `horizontal-bracket-interface`
    - 3.2.66 `horizontal-bracket-text-interface`
    - 3.2.67 `horizontal-line-spanner-interface`
    - 3.2.68 `inline-accidental-interface`
    - 3.2.69 `instrument-specific-markup-interface`
    - 3.2.70 `item-interface`
    - 3.2.71 `jump-script-interface`
    - 3.2.72 `key-cancellation-interface`
    - 3.2.73 `key-signature-interface`
    - 3.2.74 `kievan-ligature-interface`
    - 3.2.75 `ledger-line-spanner-interface`
    - 3.2.76 `ledgered-grob-interface`
    - 3.2.77 `ledgered-interface`
    - 3.2.78 `ligature-bracket-interface`
    - 3.2.79 `ligature-head-interface`
    - 3.2.80 `ligature-interface`
    - 3.2.81 `line-interface`
    - 3.2.82 `line-spanner-interface`
    - 3.2.83 `lyric-extender-interface`
    - 3.2.84 `lyric-hyphen-interface`
    - 3.2.85 `lyric-interface`
    - 3.2.86 `lyric-repeat-count-interface`
    - 3.2.87 `lyric-space-interface`
    - 3.2.88 `lyric-syllable-interface`
    - 3.2.89 `mark-interface`
    - 3.2.90 `measure-counter-interface`
    - 3.2.91 `measure-grouping-interface`
    - 3.2.92 `measure-spanner-interface`
    - 3.2.93 `melody-spanner-interface`
    - 3.2.94 `mensural-ligature-interface`
    - 3.2.95 `metronome-mark-interface`
    - 3.2.96 `multi-measure-interface`
    - 3.2.97 `multi-measure-rest-interface`
    - 3.2.98 `multi-measure-rest-number-interface`
    - 3.2.99 `musical-paper-column-interface`
    - 3.2.100 `non-musical-paper-column-interface`
    - 3.2.101 `note-collision-interface`
    - 3.2.102 `note-column-interface`
    - 3.2.103 `note-head-interface`
    - 3.2.104 `note-name-interface`
    - 3.2.105 `note-spacing-interface`
    - 3.2.106 `number-interface`
    - 3.2.107 `optional-material-bracket-interface`
    - 3.2.108 `ottava-bracket-interface`
    - 3.2.109 `outside-staff-axis-group-interface`
    - 3.2.110 `outside-staff-interface`
    - 3.2.111 `paper-column-interface`
    - 3.2.112 `parentheses-interface`
    - 3.2.113 `passage-delimiter-interface`
    - 3.2.114 `percent-repeat-interface`
    - 3.2.115 `piano-pedal-bracket-interface`
    - 3.2.116 `piano-pedal-interface`
    - 3.2.117 `piano-pedal-script-interface`
    - 3.2.118 `pitched-trill-interface`
    - 3.2.119 `pure-from-neighbor-interface`
    - 3.2.120 `rehearsal-mark-interface`
    - 3.2.121 `rest-collision-interface`
    - 3.2.122 `rest-interface`
    - 3.2.123 `rhythmic-grob-interface`
    - 3.2.124 `rhythmic-head-interface`
    - 3.2.125 `script-column-interface`
    - 3.2.126 `script-interface`
    - 3.2.127 `section-label-interface`
    - 3.2.128 `segno-mark-interface`
    - 3.2.129 `self-alignment-interface`
    - 3.2.130 `semi-tie-column-interface`
    - 3.2.131 `semi-tie-interface`
    - 3.2.132 `separation-item-interface`
    - 3.2.133 `side-position-interface`
    - 3.2.134 `signum-repetitionis-interface`
    - 3.2.135 `slur-interface`
    - 3.2.136 `spaceable-grob-interface`
    - 3.2.137 `spacing-interface`
    - 3.2.138 `spacing-options-interface`
    - 3.2.139 `spacing-spanner-interface`
    - 3.2.140 `span-bar-interface`
    - 3.2.141 `span-bar-stub-interface`
    - 3.2.142 `spanner-interface`
    - 3.2.143 `staff-ellipsis-interface`
    - 3.2.144 `staff-grouper-interface`
    - 3.2.145 `staff-highlight-interface`
    - 3.2.146 `staff-spacing-interface`
    - 3.2.147 `staff-symbol-interface`
    - 3.2.148 `staff-symbol-referencer-interface`
    - 3.2.149 `stanza-number-interface`
    - 3.2.150 `stem-interface`
    - 3.2.151 `stem-tremolo-interface`
    - 3.2.152 `sticky-grob-interface`
    - 3.2.153 `string-number-interface`
    - 3.2.154 `stroke-finger-interface`
    - 3.2.155 `system-interface`
    - 3.2.156 `system-start-delimiter-interface`
    - 3.2.157 `system-start-text-interface`
    - 3.2.158 `tab-note-head-interface`
    - 3.2.159 `text-interface`
    - 3.2.160 `text-mark-interface`
    - 3.2.161 `text-script-interface`
    - 3.2.162 `tie-column-interface`
    - 3.2.163 `tie-interface`
    - 3.2.164 `time-signature-interface`
    - 3.2.165 `trill-pitch-accidental-interface`
    - 3.2.166 `trill-spanner-interface`
    - 3.2.167 `tuplet-bracket-interface`
    - 3.2.168 `tuplet-number-interface`
    - 3.2.169 `unbreakable-spanner-interface`
    - 3.2.170 `vaticana-ligature-interface`
    - 3.2.171 `volta-bracket-interface`
    - 3.2.172 `volta-interface`
  - 3.3 User backend properties
  - 3.4 Internal backend properties
- 4 Scheme functions
- Appendix A Indices
  - A.1 Function index