### 3.2.3 Creating footnotes

Footnotes may be used in many different situations. In all cases, a ‘footnote mark’ is placed as a reference in text or music, and the corresponding ‘footnote text’ appears at the bottom of the same page.

Footnotes within music expressions and footnotes in stand-alone text outside music expressions are created in different ways.

#### Footnotes in music expressions

#### Music footnotes overview

Footnotes in music expressions fall into two categories:

Event-based footnotes

  are attached to a particular event. Examples for such events are single notes, articulations (like fingering indications, accents, dynamics), and post-events (like slurs and manual beams). The general form for event-based footnotes is as follows:

  >     [direction] \footnote [mark] offset footnote music

Time-based footnotes

  are bound to a particular point of time in a musical context. Some commands like `\time` and `\clef` don’t actually use events for creating objects like time signatures and clefs. Neither does a chord create an event of its own: its stem or flag is created at the end of a time step (nominally through one of the note events inside). Exactly which of a chord’s multiple note events will be deemed the root cause of a stem or flag is undefined. So for annotating those, time-based footnotes are preferable as well.

  A time-based footnote allows such layout objects to be annotated without referring to an event. The general form for Time-based footnotes is:

  >     \footnote [mark] offset footnote [Context].GrobName

The elements for both forms are:

direction

  If (and only if) the `\footnote` is being applied to a post-event or articulation, it must be preceded with a direction indicator (`-, _, ^`) in order to attach music (with a footnote mark) to the preceding note or rest.

mark

  is a markup or string specifying the footnote mark which is used for marking both the reference point and the footnote itself at the bottom of the page. It may be omitted (or equivalently replaced with `\default`) in which case a number in sequence will be generated automatically. Such numerical sequences restart on each page containing a footnote.

offset

  is a number pair such as ‘`#(2 . 1)`’ specifying the X and Y offsets in units of staff-spaces from the boundary of the object where the mark should be placed. Positive values of the offsets are taken from the right/top edge, negative values from the left/bottom edge and zero implies the mark is centered on the edge.

Context

  is the context in which the grob being footnoted is created. It may be omitted if the grob is in a bottom context, e.g. a `Voice` context.

GrobName

  specifies a type of grob to mark (like ‘`Flag`’). If it is specified, the footnote is not attached to a music expression in particular, but rather to all grobs of the type specified which occur at that moment of musical time.

footnote

  is the markup or string specifying the footnote text to use at the bottom of the page.

music

  is the music event or post-event or articulation that is being annotated.

#### Event-based footnotes

A footnote may be attached to a layout object directly caused by the event corresponding to music with the syntax:

>     \footnote [mark] offset footnote music

>     \book {
>       \header { tagline = ##f }
>       \relative c'' {
>         \footnote #'(-1 . 3) "A note" a4
>         a4
>         \footnote #'(2 . 2) "A rest" r4
>         a4
>       }
>     }

Marking a whole chord with an event-based footnote is not possible: a chord, even one containing just a single note, does not produce an actual event of its own. However, individual notes inside of the chord can be marked:

>     \book {
>       \header { tagline = ##f }
>       \relative c'' {
>         \footnote #'(2 . 3) "Does not work" <a-3>2
>         <\footnote #'(-2 . -3) "Does work" a-3>4
>         <a-3 \footnote #'(3 . 1/2) "Also works" c-5>4
>       }
>     }

If the footnote is to be attached to a post-event or articulation the `\footnote` command must be preceded by a direction indicator, `-, _, ^`, and followed by the post-event or articulation to be annotated as the music argument. In this form the `\footnote` can be considered to be simply a copy of its last argument with a footnote mark attached to it. The syntax is:

>     direction \footnote [mark] offset footnote music

>     \book {
>       \header { tagline = ##f }
>       \relative c'' {
>         a4_\footnote #'(0 . -1) "A slur forced down" (
>         b8^\footnote #'(1 . 0.5) "A manual beam forced up" [
>         b8 ]
>         c4 )
>         c-\footnote #'(1 . 1) "Tenuto" --
>       }
>     }

#### Time-based footnotes

If the layout object being footmarked is indirectly caused by an event (like an `Accidental` or `Stem` caused by a `NoteHead` event), the GrobName of the layout object is required after the footnote text instead of music:

>     \book {
>       \header { tagline = ##f }
>       \relative c'' {
>         \footnote #'(-1 . -3) "A flat" Accidental
>         aes4 c
>         \footnote #'(-1 . 0.5) "Another flat" Accidental
>         ees
>         \footnote #'(1 . -2) "A stem" Stem
>         aes
>       }
>     }

Note, however, that when a GrobName is specified, a footnote will be attached to all grobs of that type at the current time step:

>     \book {
>       \header { tagline = ##f }
>       \relative c' {
>         \footnote #'(-1 . 3) "A flat" Accidental
>         <ees ges bes>4
>         \footnote #'(2 . 0.5) "Articulation" Script
>         c'->-.
>       }
>     }

A note inside of a chord can be given an individual (event-based) footnote. A ‘`NoteHead`’ is the only grob directly caused from a chord note, so an event-based footnote command is only suitable for adding a footnote to the ‘`NoteHead`’ within a chord. All other chord note grobs are indirectly caused. The `\footnote` command itself offers no syntax for specifying both a particular grob type as well as a particular event to attach to. However, one can use a time-based `\footnote` command for specifying the grob type, and then prefix this command with `\single` in order to have it applied to just the following event:

>     \book {
>       \header { tagline = ##f }
>       \relative c'' {
>         < \footnote #'(1 . -2) "An A" a
>           \single \footnote #'(-1 . -1) "A sharp" Accidental
>           cis
>           \single \footnote #'(0.5 . 0.5) "A flat" Accidental
>           ees fis
>         >2
>       }
>     }

Note: When footnotes are attached to several musical elements at the same musical moment, as they are in the example above, the footnotes are numbered from the higher to the lower elements as they appear in the printed output, not in the order in which they are written in the input stream.

Layout objects like clefs and key-change signatures are mostly caused as a consequence of changed properties rather than actual events. Others, like bar lines and bar numbers, are a direct consequence of timing. For this reason, footnotes on such objects have to be based on their musical timing. Time-based footnotes are also preferable when marking features like stems and beams on chords: while such per-chord features are nominally assigned to one event inside the chord, relying on a particular choice would be imprudent.

The layout object in question must always be explicitly specified for time-based footnotes, and the appropriate context must be specified if the grob is created in a context other than the bottom context.

>     \book {
>       \header { tagline = ##f }
>       \relative c'' {
>         r1 |
>         \footnote #'(-0.5 . -1) "Meter change" Staff.TimeSignature
>         \time 3/4
>         \footnote #'(1 . -1) "Chord stem" Stem
>         <c e g>4 q q
>         \footnote #'(-0.5 . 1) "Bar line" Staff.BarLine
>         q q
>         \footnote #'(0.5 . -1) "Key change" Staff.KeySignature
>         \key c \minor
>         q
>       }
>     }

Custom marks can be used as alternatives to numerical marks, and the annotation line joining the marked object to the mark can be suppressed:

>     \book {
>       \header { tagline = ##f }
>       \relative c' {
>         \footnote "*" #'(0.5 . -2) \markup { \italic "* The first note" } a'4
>         b8
>         \footnote \markup { \super "$" } #'(0.5 . 1)
>           \markup { \super "$" \italic " The second note" } e
>         c4
>         \once \override Score.FootnoteItem.annotation-line = ##f
>         b-\footnote \markup \tiny "+" #'(0.1 . 0.1)
>           \markup { \super "+" \italic " Editorial" } \p
>       }
>     }

More examples of custom marks are shown in Footnotes in stand-alone text.

#### Footnotes in stand-alone text

These are for use in markup outside of music expressions. They do not have a line drawn to their point of reference: their marks simply follow the referenced markup. Marks can be inserted automatically, in which case they are numerical. Alternatively, custom marks can be provided manually.

Footnotes to stand-alone text with automatic and custom marks are created in different ways.

#### Footnotes in stand-alone text with automatic marks

The syntax of a footnote in stand-alone text with automatic marks is

>     \markup { … \auto-footnote text footnote … }

The elements are:

text

  is the markup or string to be marked.

footnote

  is the markup or string specifying the footnote text to use at the bottom of the page.

For example:

>     \book {
>       \header { tagline = ##f }
>       \markup {
>         "A simple"
>         \auto-footnote "tune" \italic " By me"
>         "is shown below.  It is a"
>         \auto-footnote "recent" \italic " Aug 2012"
>         "composition."
>       }
>       \relative c' {
>         a'4 b8 e c4 d
>       }
>     }

#### Footnotes in stand-alone text with custom marks

The syntax of a footnote in stand-alone text with custom marks is

>     \markup { … \footnote mark footnote … }

The elements are:

mark

  is a markup or string specifying the footnote mark which is used for marking the reference point. Note that this mark is not inserted automatically before the footnote itself.

footnote

  is the markup or string specifying the footnote text to use at the bottom of the page, preceded by the mark.

Any easy-to-type character such as * or + may be used as a mark, as shown in Footnotes in music expressions. Alteratively, ASCII aliases may be used (see ASCII aliases):

>     \book {
>       \paper { #(include-special-characters) }
>       \header { tagline = ##f }
>       \markup {
>         "A simple tune"
>         \footnote "*" \italic "* By me"
>         "is shown below.  It is a recent"
>         \footnote \super &dagger; \concat {
>           \super &dagger; \italic " Aug 2012"
>         }
>         "composition."
>       }
>       \relative c' {
>         a'4 b8 e c4 d
>       }
>     }

Unicode character codes may also be used to specify marks (see Unicode):

>     \book {
>       \header { tagline = ##f }
>       \markup {
>         "A simple tune"
>         \footnote \super \char##x00a7 \concat {
>           \super \char##x00a7 \italic " By me"
>         }
>         "is shown below.  It is a recent"
>         \footnote \super \char##x00b6 \concat {
>           \super \char##x00b6 \italic " Aug 2012"
>         }
>         "composition."
>       }
>       \relative c' {
>         a'4 b8 e c4 d
>       }
>     }

#### See also

Learning Manual: Objects and interfaces.

Notation Reference: ASCII aliases, Balloon help, List of special characters, Text marks, Text scripts, Unicode.

Internals Reference: FootnoteEvent, FootnoteItem, FootnoteSpanner, Footnote_engraver.

#### Known issues and warnings

Multiple footnotes for the same page can only be stacked, one above the other; they cannot be printed on the same line.

Footnotes cannot be attached to `MultiMeasureRests` or automatic beams or lyrics.

Footnote marks may collide with staves, `\markup` objects, other footnote marks and annotation lines.

其他语言：deutsch, español, français, italiano, 日本語。
About automatic language selection.

#### LilyPond — Notation Reference v2.18.2 (稳定分支).