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13 @node Changing defaults
14 @chapter Changing defaults
16 The purpose of LilyPond's design is to provide the finest quality
17 output by default. Nevertheless, it may happen that you need to
18 change this default layout. The layout is controlled through a large
19 number of @q{knobs and switches} collectively called @q{properties}.
20 A tutorial introduction to accessing and modifying these properties
21 can be found in the Learning Manual, see @rlearning{Tweaking output}.
22 This should be read first. This chapter covers similar ground, but
23 in a style more appropriate to a reference manual.
25 @cindex Internals Reference
27 The definitive description of the controls available for tuning can
28 be found in a separate document: @rinternalsnamed{Top,the Internals
29 Reference}. That manual lists all the variables, functions and
30 options available in LilyPond. It is written as a HTML document,
32 @c leave the @uref as one long line.
33 @uref{http://@/lilypond@/.org/@/doc/@/stable/@/Documentation/@/user/@/lilypond@/-internals/,on@/-line},
34 and is also included with the LilyPond documentation package.
36 Internally, LilyPond uses Scheme (a LISP dialect) to provide
37 infrastructure. Overriding layout decisions in effect accesses the
38 program internals, which requires Scheme input. Scheme elements are
39 introduced in a @code{.ly} file with the hash mark
40 @code{#}.@footnote{@rextend{Scheme tutorial}, contains a short tutorial
41 on entering numbers, lists, strings, and symbols in Scheme.}
45 * Interpretation contexts::
46 * Explaining the Internals Reference::
47 * Modifying properties::
48 * Useful concepts and properties::
50 * Using music functions::
54 @node Interpretation contexts
55 @section Interpretation contexts
57 This section describes what contexts are, and how to modify them.
60 * Contexts explained::
62 * Keeping contexts alive::
63 * Modifying context plug-ins::
64 * Changing context default settings::
65 * Defining new contexts::
72 @rlearning{Contexts and engravers}.
75 @file{ly/@/engraver@/-init@/.ly},
76 @file{ly/@/performer@/-init@/.ly}.
79 @rlsr{Contexts and engravers}.
82 @rinternals{Contexts},
83 @rinternals{Engravers and Performers}.
86 @node Contexts explained
87 @subsection Contexts explained
90 @c TODO Rethink and rewrite
92 >> > > - list of contexts: my *danger unmaintainable*
93 >> > > alarm just went off. I'm
95 I knew it would... And leaving out some of them is perfectly fine
97 I do think that a list like this, with the main contexts and a
99 description of what they do (perhaps also with a note about what
101 behavior is associated with each of them, but this may be
103 should be there, and then we could simply list the remaining ones
105 further explanation and with links to the IR.
108 @c TODO Improve layout, order and consistency of wording -td
110 @c TODO Add introduction which explains contexts in generality -td
112 @c TODO Describe propagation of property values -td
114 Contexts are arranged hierarchically:
117 * Score - the master of all contexts::
118 * Top-level contexts - staff containers::
119 * Intermediate-level contexts - staves::
120 * Bottom-level contexts - voices::
123 @node Score - the master of all contexts
124 @unnumberedsubsubsec Score - the master of all contexts
126 This is the top level notation context. No other context can
127 contain a Score context. By default the Score context handles
128 the administration of time signatures and makes sure that items
129 such as clefs, time signatures, and key-signatures are aligned
132 A Score context is instantiated implicitly when a
133 @code{\score @{@dots{}@}} or @code{\layout @{@dots{}@}} block is
134 processed, or explicitly when a @code{\new Score} command is
137 @node Top-level contexts - staff containers
138 @unnumberedsubsubsec Top-level contexts - staff containers
140 @strong{@emph{StaffGroup}}
142 Groups staves while adding a bracket on the left side, grouping
143 the staves together. The bar lines of the contained staves are
144 connected vertically. @code{StaffGroup} only consists of a collection
145 of staves, with a bracket in front and spanning bar lines.
147 @strong{@emph{ChoirStaff}}
149 Identical to @code{StaffGroup} except that the bar lines of the
150 contained staves are not connected vertically.
152 @strong{@emph{GrandStaff}}
154 A group of staves, with a brace on the left side, grouping the
155 staves together. The bar lines of the contained staves are
156 connected vertically.
158 @strong{@emph{PianoStaff}}
160 Just like @code{GrandStaff}, but with support for instrument names
161 to the left of each system.
163 @node Intermediate-level contexts - staves
164 @unnumberedsubsubsec Intermediate-level contexts - staves
166 @strong{@emph{Staff}}
168 Handles clefs, bar lines, keys, accidentals. It can contain
169 @code{Voice} contexts.
171 @strong{@emph{RhythmicStaff}}
173 Like @code{Staff} but for printing rhythms. Pitches are ignored;
174 the notes are printed on one line.
176 @strong{@emph{TabStaff}}
178 Context for generating tablature. By default lays the music
179 expression out as a guitar tablature, printed on six lines.
181 @strong{@emph{DrumStaff}}
183 Handles typesetting for percussion. Can contain @code{DrumVoice}
185 @strong{@emph{VaticanaStaff}}
187 Same as @code{Staff}, except that it is designed for typesetting
188 a piece in gregorian style.
190 @strong{@emph{MensuralStaff}}
192 Same as @code{Staff}, except that it is designed for typesetting
193 a piece in mensural style.
195 @node Bottom-level contexts - voices
196 @unnumberedsubsubsec Bottom-level contexts - voices
198 Voice-level contexts initialise certain properties and start
199 appropriate engravers. Being bottom-level contexts, they cannot
200 contain other contexts.
202 @strong{@emph{Voice}}
204 Corresponds to a voice on a staff. This context handles the
205 conversion of dynamic signs, stems, beams, super- and sub-scripts,
206 slurs, ties, and rests. You have to instantiate this explicitly
207 if you require multiple voices on the same staff.
209 @strong{@emph{VaticanaVoice}}
211 Same as @code{Voice}, except that it is designed for typesetting
212 a piece in gregorian style.
214 @strong{@emph{MensuralVoice}}
216 Same as @code{Voice}, with modifications for typesetting a piece in
219 @strong{@emph{Lyrics}}
221 Corresponds to a voice with lyrics. Handles the printing of a
222 single line of lyrics.
224 @strong{@emph{DrumVoice}}
226 The voice context used in a percussion staff.
228 @strong{@emph{FiguredBass}}
230 The context in which @code{BassFigure} objects are created from
231 input entered in @code{\figuremode} mode.
233 @strong{@emph{TabVoice}}
235 The voice context used within a @code{TabStaff} context. Usually
236 left to be created implicitly.
238 @strong{@emph{CueVoice}}
240 A voice context used to render notes of a reduced size, intended
241 primarily for adding cue notes to a staff, see @ref{Formatting
242 cue notes}. Usually left to be created implicitly.
244 @strong{@emph{ChordNames}}
246 Typesets chord names.
251 Then the following, which I don't know what to do with:
253 * GregorianTranscriptionVoice
254 * GregorianTranscriptionStaff
257 Engraves fretboards from chords. Not easy... Not
259 There is now some documentation on FretBoards in the NR, under
260 instrument-specific notation -- cds.
265 Hard coded entry point for LilyPond. Cannot be tuned.
267 Silently discards all musical information given to this
272 @node Creating contexts
273 @subsection Creating contexts
275 @c TODO \new Score and \score
276 @c TODO more complete descriptions rather than learning style
278 For scores with only one voice and one staff, contexts are
279 created automatically. For more complex scores, it is necessary to
280 create them by hand. There are three commands that do this.
285 The easiest command is @code{\new}, and it also the quickest to type.
286 It is prepended to a music expression, for example
290 @cindex Context, creating
293 \new @var{type} @var{music expression}
297 where @var{type} is a context name (like @code{Staff} or
298 @code{Voice}). This command creates a new context, and starts
299 interpreting the @var{music expression} with that.
301 A practical application of @code{\new} is a score with many
302 staves. Each part that should be on its own staff, is preceded with
305 @lilypond[quote,verbatim,relative=2,ragged-right,fragment]
312 The @code{\new} command may also give a name to the context,
315 \new @var{type} = @var{id} @var{music}
317 However, this user specified name is only used if there is no other
318 context already earlier with the same name.
324 Like @code{\new}, the @code{\context} command also directs a music
325 expression to a context object, but gives the context an explicit name. The
329 \context @var{type} = @var{id} @var{music}
332 This form will search for an existing context of type @var{type}
333 called @var{id}. If that context does not exist yet, a new
334 context with the specified name is created. This is useful if
335 the context is referred to later on. For example, when
336 setting lyrics the melody is in a named context
339 \context Voice = "@b{tenor}" @var{music}
343 so the texts can be properly aligned to its notes,
346 \new Lyrics \lyricsto "@b{tenor}" @var{lyrics}
351 Another possible use of named contexts is funneling two different
352 music expressions into one context. In the following example,
353 articulations and notes are entered separately,
357 arts = @{ s4-. s4-> @}
360 They are combined by sending both to the same @code{Voice} context,
364 \new Staff \context Voice = "A" \music
365 \context Voice = "A" \arts
368 @lilypond[quote,ragged-right]
372 \new Staff \context Voice = "A" \music
373 \context Voice = "A" \arts
377 With this mechanism, it is possible to define an Urtext (original
378 edition), with the option to put several distinct articulations on the
381 @cindex creating contexts
384 The third command for creating contexts is
386 \context @var{type} @var{music}
391 This is similar to @code{\context} with @code{= @var{id}}, but matches
392 any context of type @var{type}, regardless of its given name.
394 This variant is used with music expressions that can be interpreted at
395 several levels. For example, the @code{\applyOutput} command (see
396 @rextend{Running a function on all layout objects}). Without an explicit
397 @code{\context}, it is usually applied to @code{Voice}
400 \applyOutput #'@var{context} #@var{function} % apply to Voice
403 To have it interpreted at the @code{Score} or @code{Staff} level use
407 \applyOutput #'Score #@var{function}
408 \applyOutput #'Staff #@var{function}
413 @node Keeping contexts alive
414 @subsection Keeping contexts alive
416 @cindex contexts, keeping alive
417 @cindex contexts, lifetime
419 Contexts are usually terminated at the first musical moment in
420 which they have nothing to do. So @code{Voice} contexts die as
421 soon as they contain no events; @code{Staff} contexts die as soon
422 as all the @code{Voice} contexts within them contain no events; etc.
423 This can cause difficulties if earlier contexts which have died
424 have to be referenced, for example, when changing staves with
425 @code{\change} commands, associating lyrics with a voice with
426 @code{\lyricsto} commands, or when adding further musical events to
429 There is an exception to this general rule: just one of the
430 @code{Voice} contexts in a @code{Staff} context or in a
431 @code{<<...>>} construct will always persist to the end of the
432 enclosing @code{Staff} context or @code{<<...>>} construct, even
433 though there may be periods when it has nothing to do. The context
434 to persist in this way will be the first one encountered in the
435 first enclosed @code{@{...@}} construct, ignoring any in enclosed
436 @code{<<...>>} constructs.
438 Any context can be kept alive by ensuring it has something to do at
439 every musical moment. @code{Staff} contexts are kept alive by
440 ensuring one of their voices is kept alive. One way of doing this
441 is to add spacer rests to a voice in parallel with the real music.
442 These need to be added to every @code{Voice} context which needs to
443 be kept alive. If several voices are to be used sporadically it is
444 safest to keep them all alive rather than attempting to rely on the
445 exceptions mentioned above.
447 In the following example, both voice A and voice B are kept alive
448 in this way for the duration of the piece:
450 @lilypond[quote,verbatim]
451 musicA = \relative c'' { d4 d d d }
452 musicB = \relative c'' { g4 g g g }
455 \new Voice = "A" { s1*5 } % Keep Voice "A" alive for 5 bars
456 \new Voice = "B" { s1*5 } % Keep Voice "B" alive for 5 bars
461 \context Voice = "A" {
465 \context Voice = "B" {
469 \context Voice = "A" { \musicA }
470 \context Voice = "B" { \musicB }
471 \context Voice = "A" { \musicA }
482 @cindex lyrics, aligning with sporadic melody
484 The following example shows how a sporadic melody line with lyrics
485 might be written using this approach. In a real situation the
486 melody and accompaniment would consist of several different
489 @lilypond[quote,verbatim]
490 melody = \relative c'' { a4 a a a }
491 accompaniment = \relative c' { d4 d d d }
492 words = \lyricmode { These words fol -- low the mel -- o -- dy }
495 \new Staff = "music" {
497 \new Voice = "melody" {
499 s1*4 % Keep Voice "melody" alive for 4 bars
502 \new Voice = "accompaniment" {
507 \context Voice = "melody" { \melody }
508 \context Voice = "accompaniment" { \accompaniment }
510 \context Voice = "accompaniment" { \accompaniment }
512 \context Voice = "melody" { \melody }
513 \context Voice = "accompaniment" { \accompaniment }
518 \new Lyrics \with { alignAboveContext = #"music" }
519 \lyricsto "melody" { \words }
524 An alternative way, which may be better in many circumstances, is
525 to keep the melody line alive by simply including spacer notes to
526 line it up correctly with the accompaniment:
528 @lilypond[quote,verbatim]
529 melody = \relative c'' {
535 accompaniment = \relative c' {
541 words = \lyricmode { These words fol -- low the mel -- o -- dy }
545 \new Staff = "music" {
547 \new Voice = "melody" {
551 \new Voice = "accompaniment" {
557 \new Lyrics \with { alignAboveContext = #"music" }
558 \lyricsto "melody" { \words }
564 @node Modifying context plug-ins
565 @subsection Modifying context plug-ins
567 @c TODO Should this be Modifying engravers or Modifying contexts?
569 Notation contexts (like @code{Score} and @code{Staff}) not only
571 they also contain plug-ins called @q{engravers} that create notation
572 elements. For example, the @code{Voice} context contains a
573 @code{Note_head_engraver} and the @code{Staff} context contains a
574 @code{Key_signature_engraver}.
576 For a full a description of each plug-in, see
578 @rinternals{Engravers and Performers}.
581 Internals Reference @expansion{} Translation @expansion{} Engravers.
583 Every context described in
585 @rinternals{Contexts}
588 Internals Reference @expansion{} Translation @expansion{} Context.
590 lists the engravers used for that context.
593 It can be useful to shuffle around these plug-ins. This is done by
594 starting a new context with @code{\new} or @code{\context}, and
600 \new @var{context} \with @{
613 where the @dots{} should be the name of an engraver. Here is a simple
614 example which removes @code{Time_signature_engraver} and
615 @code{Clef_engraver} from a @code{Staff} context,
617 @lilypond[quote,relative=1,verbatim,fragment]
623 \remove "Time_signature_engraver"
624 \remove "Clef_engraver"
631 In the second staff there are no time signature or clef symbols. This
632 is a rather crude method of making objects disappear since it will affect
633 the entire staff. This method also influences the spacing, which may or
634 may not be desirable. More sophisticated methods of blanking objects
635 are shown in @rlearning{Visibility and color of objects}.
637 The next example shows a practical application. Bar lines and time
638 signatures are normally synchronized across the score. This is done
639 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
640 This plug-in keeps an administration of time signature, location
641 within the measure, etc. By moving these engraver from @code{Score} to
642 @code{Staff} context, we can have a score where each staff has its own
645 @cindex polymetric scores
646 @cindex Time signatures, multiple
648 @lilypond[quote,relative=1,ragged-right,verbatim,fragment]
650 \remove "Timing_translator"
651 \remove "Default_bar_line_engraver"
654 \consists "Timing_translator"
655 \consists "Default_bar_line_engraver"
661 \consists "Timing_translator"
662 \consists "Default_bar_line_engraver"
672 Usually the order in which the engravers are specified
673 does not matter, but in a few special cases the order
674 is important, for example where one engraver writes
675 a property and another reads it, or where one engraver
676 creates a grob and another must process it. The order in
677 which the engravers are specified is the order in which
678 they are called to carry out their processing.
680 The following orderings are important: the
681 @code{Bar_engraver} must normally be first, and
682 the @code{New_fingering_engraver} must come before
683 the @code{Script_column_engraver}. There may be others
684 with ordering dependencies.
686 @node Changing context default settings
687 @subsection Changing context default settings
689 The context settings which are to be used by default in
690 @code{Score}, @code{Staff} and @code{Voice} contexts may be specified
691 in a @code{\layout} block, as illustrated in the following example.
692 The @code{\layout} block should be placed within the @code{\score}
693 block to which it is to apply, but outside any music.
695 Note that the @code{\set} command itself and the context must be
696 omitted when the context default values are specified in this way:
698 @lilypond[quote,verbatim]
701 a4^"Really small, thicker stems, no time signature" a a a
708 \override Stem #'thickness = #4.0
709 \remove "Time_signature_engraver"
715 In this example, the @code{\Staff} command specifies that the
716 subsequent specifications are to be applied to all staves within
719 Modifications can be made to the @code{Score} context or all
720 @code{Voice} contexts in a similar way.
724 It is not possible to collect context changes in a variable and apply
725 them to a @code{\context} definition by referring to that variable.
727 The @code{\RemoveEmptyStaffContext} will overwrite your current
728 @code{\Staff} settings. If you wish to change the defaults for a
729 staff which uses @code{\RemoveEmptyStaffContext}, you must do so
730 after calling @code{\RemoveEmptyStaffContext}, ie
735 \RemoveEmptyStaffContext
737 \override Stem #'thickness = #4.0
742 @c TODO: add \with in here.
746 @node Defining new contexts
747 @subsection Defining new contexts
749 @cindex contexts, defining new
750 @cindex engravers, including in contexts
765 Specific contexts, like @code{Staff} and @code{Voice}, are made of
766 simple building blocks. It is possible to create new types of
767 contexts with different combinations of engraver plug-ins.
769 The next example shows how to build a different type of
770 @code{Voice} context from scratch. It will be similar to
771 @code{Voice}, but only prints centered slash note heads. It can be used
772 to indicate improvisation in jazz pieces,
774 @lilypond[quote,ragged-right]
777 \type "Engraver_group"
778 \consists "Note_heads_engraver"
779 \consists "Rhythmic_column_engraver"
780 \consists "Text_engraver"
781 \consists Pitch_squash_engraver
782 squashedPosition = #0
783 \override NoteHead #'style = #'slash
784 \override Stem #'transparent = ##t
788 \accepts "ImproVoice"
792 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
793 c4 c^"undress" c_"while playing :)" c }
799 These settings are defined within a @code{\context} block inside a
800 @code{\layout} block,
810 In the following discussion, the example input shown should go in place
811 of the @dots{} in the previous fragment.
813 First it is necessary to define a name for the new context:
819 Since it is similar to the @code{Voice}, we want commands that work
820 on (existing) @code{Voice}s to remain working. This is achieved by
821 giving the new context an alias @code{Voice},
827 The context will print notes and instructive texts, so we need to add
828 the engravers which provide this functionality,
831 \consists Note_heads_engraver
832 \consists Text_engraver
835 but we only need this on the center line,
838 \consists Pitch_squash_engraver
839 squashedPosition = #0
842 The @rinternals{Pitch_squash_engraver} modifies note heads (created
843 by @rinternals{Note_heads_engraver}) and sets their vertical
844 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
847 The notes look like a slash, and have no stem,
850 \override NoteHead #'style = #'slash
851 \override Stem #'transparent = ##t
854 All these plug-ins have to cooperate, and this is achieved with a
855 special plug-in, which must be marked with the keyword @code{\type}.
856 This should always be @code{Engraver_group}.
859 \type "Engraver_group"
867 \type "Engraver_group"
868 \consists "Note_heads_engraver"
869 \consists "Text_engraver"
870 \consists Pitch_squash_engraver
871 squashedPosition = #0
872 \override NoteHead #'style = #'slash
873 \override Stem #'transparent = ##t
879 Contexts form hierarchies. We want to hang the @code{ImproVoice}
880 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
881 modify the @code{Staff} definition with the @code{\accepts}
892 The opposite of @code{\accepts} is @code{\denies},
893 which is sometimes needed when reusing existing context definitions.
895 Putting both into a @code{\layout} block, like
905 \accepts "ImproVoice"
910 Then the output at the start of this subsection can be entered as
918 c c_"while playing :)"
925 @node Aligning contexts
926 @subsection Aligning contexts
928 New contexts may be aligned above or below existing contexts. This
929 could be useful in setting up a vocal staff (@rlearning{Vocal ensembles}) and
932 @c TODO Better example needed. Ref LM, and expand on it.
935 @funindex alignAboveContext
936 @funindex alignBelowContext
938 @lilypond[quote,ragged-right]
941 \relative c' \new Staff = "main" {
944 \new Staff \with { alignAboveContext = #"main" } \ossia
951 @cindex nested contexts
952 @cindex contexts, nested
957 Contexts like @code{PianoStaff} can contain other contexts
958 nested within them. Contexts which are acceptable for nesting
959 are defined by the @qq{accepts} list of a context. Contexts
960 which are not in this list are placed below the outer context
961 in the printed score.
962 For example, the @code{PianoStaff} context is defined by default
963 to accept @code{Staff} and @code{FiguredBass} contexts within
964 it, but not (for example) a @code{Lyrics} context. So in the
965 following structure the lyrics are placed below the piano staff
966 rather than between the two staves:
968 @lilypond[verbatim,quote,relative=1]
971 \new Staff { e4 d c2 }
972 \addlyrics { Three blind mice }
980 The @qq{accepts} list of a context can be modified to include
981 additional nested contexts, so if we wanted the lyrics to appear
982 between the two staves we could use:
984 @lilypond[verbatim,quote,relative=1]
985 \new PianoStaff \with { \accepts Lyrics }
987 \new Staff { e4 d c2 }
988 \addlyrics { Three blind mice }
996 The opposite of @code{\accepts} is @code{\denies}; this removes a
997 context from the @qq{accepts} list.
999 @node Explaining the Internals Reference
1000 @section Explaining the Internals Reference
1004 * Navigating the program reference::
1005 * Layout interfaces::
1006 * Determining the grob property::
1007 * Naming conventions::
1010 @node Navigating the program reference
1011 @subsection Navigating the program reference
1013 @c TODO remove this (it's in the LM)
1014 @c Replace with more factual directions
1016 Suppose we want to move the fingering indication in the fragment
1019 @lilypond[quote,fragment,relative=2,verbatim]
1025 If you visit the documentation on fingering instructions (in
1026 @ref{Fingering instructions}), you will notice:
1031 Internals Reference: @rinternals{Fingering}.
1036 @c outdated info; probably will delete.
1038 This fragment points to two parts of the program reference: a page
1039 on @code{FingeringEvent} and one on @code{Fingering}.
1041 The page on @code{FingeringEvent} describes the properties of the music
1042 expression for the input @code{-2}. The page contains many links
1043 forward. For example, it says
1046 Accepted by: @rinternals{Fingering_engraver},
1050 That link brings us to the documentation for the Engraver, the
1054 This engraver creates the following layout objects: @rinternals{Fingering}.
1057 In other words, once the @code{FingeringEvent}s are interpreted, the
1058 @code{Fingering_engraver} plug-in will process them.
1062 @c I can't figure out what this is supposed to mean. -gp
1064 The @code{Fingering_engraver} is also listed to create
1065 @rinternals{Fingering} objects,
1067 @c old info? it doesn't make any sense to me with our current docs.
1069 second bit of information listed under @b{See also} in the Notation
1074 The programmer's reference is available as an HTML document. It is
1075 highly recommended that you read it in HTML form, either online or
1076 by downloading the HTML documentation. This section will be much more
1077 difficult to understand if you are using the
1081 Follow the link to @rinternals{Fingering}. At the top of the
1085 Fingering objects are created by: @rinternals{Fingering_engraver} and
1086 @rinternals{New_fingering_engraver}.
1089 By following related links inside the program reference, we can follow the
1090 flow of information within the program:
1094 @item @rinternals{Fingering}:
1095 @rinternals{Fingering} objects are created by:
1096 @rinternals{Fingering_engraver}
1098 @item @rinternals{Fingering_engraver}:
1099 Music types accepted: @rinternals{fingering-event}
1101 @item @rinternals{fingering-event}:
1102 Music event type @code{fingering-event} is in Music expressions named
1103 @rinternals{FingeringEvent}
1106 This path goes against the flow of information in the program: it
1107 starts from the output, and ends at the input event. You could
1108 also start at an input event, and read with the flow of
1109 information, eventually ending up at the output object(s).
1111 The program reference can also be browsed like a normal document. It
1112 contains chapters on
1114 @rinternals{Music definitions},
1117 @code{Music definitions}
1119 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1120 chapter lists all the definitions used and all properties that may be
1124 @node Layout interfaces
1125 @subsection Layout interfaces
1127 @cindex interface, layout
1128 @cindex layout interface
1131 The HTML page that we found in the previous section describes the
1132 layout object called @rinternals{Fingering}. Such an object is a
1133 symbol within the score. It has properties that store numbers (like
1134 thicknesses and directions), but also pointers to related objects. A
1135 layout object is also called a @emph{Grob}, which is short for Graphical
1136 Object. For more details about Grobs, see @rinternals{grob-interface}.
1138 The page for @code{Fingering} lists the definitions for the
1139 @code{Fingering} object. For example, the page says
1142 @code{padding} (dimension, in staff space):
1148 which means that the number will be kept at a distance of at least 0.5
1152 Each layout object may have several functions as a notational or
1153 typographical element. For example, the Fingering object
1154 has the following aspects
1158 Its size is independent of the horizontal spacing, unlike slurs or beams.
1161 It is a piece of text. Granted, it is usually a very short text.
1164 That piece of text is typeset with a font, unlike slurs or beams.
1167 Horizontally, the center of the symbol should be aligned to the
1168 center of the note head.
1171 Vertically, the symbol is placed next to the note and the staff.
1174 The vertical position is also coordinated with other superscript
1175 and subscript symbols.
1178 Each of these aspects is captured in so-called @emph{interface}s,
1179 which are listed on the @rinternals{Fingering} page at the bottom
1182 This object supports the following interfaces:
1183 @rinternals{item-interface},
1184 @rinternals{self-alignment-interface},
1185 @rinternals{side-position-interface}, @rinternals{text-interface},
1186 @rinternals{text-script-interface}, @rinternals{font-interface},
1187 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1190 Clicking any of the links will take you to the page of the respective
1191 object interface. Each interface has a number of properties. Some of
1192 them are not user-serviceable (@q{Internal properties}), but others
1195 We have been talking of @emph{the} @code{Fingering} object, but actually it
1196 does not amount to much. The initialization file (see
1197 @rlearning{Other sources of information})
1198 @file{scm/@/define@/-grobs@/.scm} shows the soul of the @q{object},
1203 (avoid-slur . around)
1204 (slur-padding . 0.2)
1205 (staff-padding . 0.5)
1206 (self-alignment-X . 0)
1207 (self-alignment-Y . 0)
1208 (script-priority . 100)
1209 (stencil . ,ly:text-interface::print)
1210 (direction . ,ly:script-interface::calc-direction)
1211 (font-encoding . fetaNumber)
1212 (font-size . -5) ; don't overlap when next to heads.
1213 (meta . ((class . Item)
1214 (interfaces . (finger-interface
1216 text-script-interface
1218 side-position-interface
1219 self-alignment-interface
1220 item-interface))))))
1224 As you can see, the @code{Fingering} object is nothing more than a
1225 bunch of variable settings, and the webpage in the Internals Reference
1226 is directly generated from this definition.
1229 @node Determining the grob property
1230 @subsection Determining the grob property
1232 @c TODO remove this (it's in the LM)
1233 @c Replace with more factual directions
1235 Recall that we wanted to change the position of the @b{2} in
1237 @lilypond[quote,fragment,relative=2,verbatim]
1243 Since the @b{2} is vertically positioned next to its note, we have to
1244 meddle with the interface associated with this positioning. This is
1245 done using @code{side-position-interface}. The page for this interface
1249 @code{side-position-interface}
1251 Position a victim object (this one) next to other objects (the
1252 support). The property @code{direction} signifies where to put the
1253 victim object relative to the support (left or right, up or down?)
1258 Below this description, the variable @code{padding} is described as
1263 (dimension, in staff space)
1265 Add this much extra space between objects that are next to each other.
1269 By increasing the value of @code{padding}, we can move the
1270 fingering away from the note head. The following command inserts
1271 3 staff spaces of white
1272 between the note and the fingering:
1274 \once \override Voice.Fingering #'padding = #3
1277 Inserting this command before the Fingering object is created,
1278 i.e., before @code{c2}, yields the following result:
1280 @lilypond[quote,relative=2,fragment,verbatim]
1281 \once \override Voice.Fingering #'padding = #3
1288 In this case, the context for this tweak is @code{Voice}. This
1289 fact can also be deduced from the program reference, for the page for
1290 the @rinternals{Fingering_engraver} plug-in says
1293 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1297 @node Naming conventions
1298 @subsection Naming conventions
1300 Another thing that is needed, is an overview of the various naming
1304 @item scheme functions: lowercase-with-hyphens (incl. one-word
1306 @item scheme functions: ly:plus-scheme-style
1307 @item music events, music classes and music properties:
1309 @item Grob interfaces: scheme-style
1310 @item backend properties: scheme-style (but X and Y!)
1311 @item contexts (and MusicExpressions and grobs): Capitalized or
1313 @item context properties: lowercaseFollowedByCamelCase
1315 Capitalized_followed_by_lowercase_and_with_underscores
1318 Questions to be answered:
1320 @item Which of these are conventions and which are rules?
1321 @item Which are rules of the underlying language, and which are
1325 @node Modifying properties
1326 @section Modifying properties
1328 @c TODO change the menu and subsection node names to use
1329 @c backslash once the new macro to handle the refs
1330 @c is available. Need to find and change all refs at
1331 @c the same time. -td
1334 * Overview of modifying properties::
1336 * The override command::
1337 * The tweak command::
1338 * set versus override::
1342 @node Overview of modifying properties
1343 @subsection Overview of modifying properties
1345 Each context is responsible for creating certain types of graphical
1346 objects. The settings used for printing these objects are also stored by
1347 context. By changing these settings, the appearance of objects can be
1350 There are two different kinds of properties stored in contexts:
1351 context properties and grob properties. Context properties are
1352 properties that apply to the context as a whole and control
1353 how the context itself is displayed. In contrast, grob properties
1354 apply to specific grob types that will be displayed in the context.
1356 The @code{\set} and @code{\unset} commands are used to change values
1357 for context properties. The @code{\override} and @code{\revert}
1358 commands are used to change values for grob properties.
1361 The syntax for this is
1364 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1367 Here @var{name} is the name of a graphical object, like
1368 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1369 variable of the formatting system (@q{grob property} or @q{layout
1370 property}). The latter is a symbol, so it must be quoted. The
1371 subsection @ref{Modifying properties}, explains what to fill in
1372 for @var{name}, @var{property}, and @var{value}. Here we only
1373 discuss the functionality of this command.
1378 \override Staff.Stem #'thickness = #4.0
1382 makes stems thicker (the default is 1.3, with staff line thickness as a
1383 unit). Since the command specifies @code{Staff} as context, it only
1384 applies to the current staff. Other staves will keep their normal
1385 appearance. Here we see the command in action:
1387 @lilypond[quote,verbatim,relative=2,fragment]
1389 \override Staff.Stem #'thickness = #4.0
1395 The @code{\override} command changes the definition of the @code{Stem}
1396 within the current @code{Staff}. After the command is interpreted
1397 all stems are thickened.
1399 Analogous to @code{\set}, the @var{context} argument may be left out,
1400 causing the default context @code{Voice} to be used. Adding
1401 @code{\once} applies the change during one timestep only.
1403 @lilypond[quote,fragment,verbatim,relative=2]
1405 \once \override Stem #'thickness = #4.0
1410 The @code{\override} must be done before the object is
1411 started. Therefore, when altering @emph{Spanner} objects such as slurs
1412 or beams, the @code{\override} command must be executed at the moment
1413 when the object is created. In this example,
1415 @lilypond[quote,fragment,verbatim,relative=2]
1416 \override Slur #'thickness = #3.0
1418 \override Beam #'thickness = #0.6
1423 the slur is fatter but the beam is not. This is because the command for
1424 @code{Beam} comes after the Beam is started, so it has no effect.
1426 Analogous to @code{\unset}, the @code{\revert} command for a context
1427 undoes an @code{\override} command; like with @code{\unset}, it only
1428 affects settings that were made in the same context. In other words, the
1429 @code{\revert} in the next example does not do anything.
1432 \override Voice.Stem #'thickness = #4.0
1433 \revert Staff.Stem #'thickness
1436 Some tweakable options are called @q{subproperties} and reside inside
1437 properties. To tweak those, use commands of the form
1439 @c leave this as a long long
1441 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1448 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1455 @rinternals{Backend},
1456 @rinternals{All layout objects},
1457 @rinternals{OverrideProperty},
1458 @rinternals{RevertProperty},
1459 @rinternals{PropertySet}.
1464 The back-end is not very strict in type-checking object properties.
1465 Cyclic references in Scheme values for properties can cause hangs
1466 or crashes, or both.
1470 @node The set command
1471 @subsection The @code{@bs{}set} command
1475 @cindex changing properties
1477 Each context has a set of @emph{properties}, variables contained
1478 in that context. Context properties are changed with the @code{\set}
1479 command, which has the following syntax:
1482 \set @var{context}.@var{property} = #@var{value}
1485 @var{value} is a Scheme object, which is why it must be preceded by
1486 the @code{#} character.
1488 Contexts properties are usually named in
1489 @code{studlyCaps}. They mostly control the translation from
1490 music to notation, e.g. @code{localKeySignature} (for determining
1491 whether to print accidentals), or @code{measurePosition} (for
1492 determining when to print a bar line). Context properties can
1493 change value over time while interpreting a piece of music;
1494 @code{measurePosition} is an obvious example of
1495 this. Context properties are modified with @code{\set}.
1497 For example, multimeasure rests will be combined into a single bar
1498 if the context property @code{skipBars} is set to @code{#t}:
1500 @lilypond[quote,verbatim,relative=2,fragment]
1502 \set Score.skipBars = ##t
1506 If the @var{context} argument is left out, then the property will be
1507 set in the current bottom context (typically @code{ChordNames},
1508 @code{Voice}, @code{TabVoice}, or @code{Lyrics}).
1510 @lilypond[quote,verbatim,relative=2,fragment]
1511 \set Score.autoBeaming = ##f
1515 \set autoBeaming = ##t
1523 The change is applied @q{on-the-fly}, during the music, so that the
1524 setting only affects the second group of eighth notes.
1526 Note that the bottom-most context does not always contain the property
1527 that you wish to change -- for example, attempting to set the
1528 @code{skipBars} property of the default bottom context, in this case
1529 @code{Voice}, will have no effect, because skipBars is a property of
1530 the @code{Score} context.
1532 @lilypond[quote,verbatim,relative=2,fragment]
1538 Contexts are hierarchical, so if an enclosing context was specified, for
1539 example @code{Staff}, then the change would also apply to all
1540 @code{Voice}s in the current staff.
1544 The @code{\unset} command:
1547 \unset @var{context}.@var{property}
1551 is used to remove the definition of @var{property} from
1552 @var{context}. This command removes
1553 the definition only if it is set in @var{context}.
1554 Properties that have been set in enclosing contexts will
1555 not be altered by an unset in an enclosed context:
1557 @lilypond[quote,verbatim,relative=2,fragment]
1558 \set Score.autoBeaming = ##t
1563 \unset Score.autoBeaming
1571 Like @code{\set}, the @var{context} argument does not have to be
1572 specified for a bottom context, so the two statements
1575 \set Voice.autoBeaming = ##t
1576 \set autoBeaming = ##t
1580 are equivalent if the current bottom context is @code{Voice}.
1584 Preceding a @code{\set} command by @code{\once} makes the
1585 setting apply to only a single time-step:
1587 @lilypond[quote,verbatim,relative=2,fragment]
1589 \once \set fontSize = #4.7
1594 A full description of all available context properties is in the
1595 internals reference, see
1597 @rinternals{Tunable context properties}.
1600 Translation @expansion{} Tunable context properties.
1605 Internals Reference:
1607 @rinternals{Tunable context properties}.
1610 @cindex grob properties
1611 @cindex properties, grob
1615 @node The override command
1616 @subsection The @code{\override} command
1618 There is a special type of context property: the grob
1619 description. Grob descriptions are named in @code{StudlyCaps}
1620 (starting with capital letters). They contain the
1621 @q{default settings} for a particular kind of grob as an
1622 association list. See @file{scm/@/define@/-grobs@/.scm}
1623 to see the settings for each grob description. Grob descriptions
1624 are modified with @code{\override}.
1626 @code{\override} is actually a shorthand;
1629 \override @var{context}.@var{GrobName} #'@var{property} = #@var{value}
1633 is more or less equivalent to
1635 @c leave this long line -gp
1637 \set @var{context}.@var{GrobName} =
1638 #(cons (cons '@var{property} @var{value})
1639 <previous value of @var{context}.@var{GrobName}>)
1642 The value of @code{context}.@code{GrobName} (the alist) is used to initialize
1643 the properties of individual grobs. Grobs have
1644 properties, named in Scheme style, with
1645 @code{dashed-words}. The values of grob properties change
1646 during the formatting process: formatting basically amounts
1647 to computing properties using callback functions.
1649 For example, we can increase the thickness of a note stem by
1650 overriding the @code{thickness} property of the @code{Stem}
1653 @lilypond[quote, verbatim, relative=2, fragment]
1655 \override Voice.Stem #'thickness = #3.0
1659 If no context is specified in an @code{\override}, the bottom
1662 @lilypond[quote, verbatim, relative=2, fragment]
1663 { \override Staff.Stem #'thickness = #3.0
1667 \override Stem #'thickness = #0.5
1677 @cindex reverting overrides
1678 @cindex overrides, reverting
1680 The effects of @code{\override} can be undone by @code{\revert}:
1682 @lilypond[quote, verbatim, relative=2, fragment]
1684 \override Voice.Stem #'thickness = #3.0
1686 \revert Voice.Stem #'thickness
1690 The effects of @code{\override} and @code{\revert} apply to all
1691 grobs in the affected context from the current time forward:
1693 @lilypond[quote, verbatim, relative=2, fragment]
1698 \override Staff.Stem #'thickness = #3.0
1702 \revert Staff.Stem #'thickness
1710 @cindex overriding for only one moment
1712 @code{\once} can be used with @code{\override}
1713 to affect only the current time step:
1715 @lilypond[quote, verbatim, relative=2, fragment]
1719 \override Stem #'thickness = #3.0
1723 \once \override Stem #'thickness = #3.0
1732 Commands which change output generally look like
1735 \override Voice.Stem #'thickness = #3.0
1739 To construct this tweak we must determine these bits of information:
1742 @item the context: here @code{Voice}.
1743 @item the layout object: here @code{Stem}.
1744 @item the layout property: here @code{thickness}.
1745 @item a sensible value: here @code{3.0}.
1748 Some tweakable options are called @q{subproperties} and reside inside
1749 properties. To tweak those, use commands in the form
1752 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1755 @cindex internal documentation
1756 @cindex finding graphical objects
1757 @cindex graphical object descriptions
1760 @cindex internal documentation
1762 For many properties, regardless of the data type of the property, setting the
1763 property to false ( @code{##f} ) will result in turning it off, causing
1764 LilyPond to ignore that property entirely. This is particularly useful for
1765 turning off grob properties which may otherwise be causing problems.
1767 We demonstrate how to glean this information from the notation manual
1768 and the program reference.
1773 Internals Reference:
1774 @rinternals{Backend}
1776 @node The tweak command
1777 @subsection The @code{\tweak} command
1782 Changing grob properties
1783 with @code{\override} causes the changes to apply to all of the
1784 given grobs in the context at the moment the change applies.
1785 Sometimes, however, it is desirable to have changes apply to just
1786 one grob, rather than to all grobs in the affected context. This is
1787 accomplished with the @code{\tweak} command, which has the following
1791 \tweak #'@code{grob-property} #@code{value}
1794 The @code{\tweak} command applies to the object that immediately
1795 follows @code{value} in the music stream.
1798 In some cases, it is possible to take a short-cut for tuning
1799 graphical objects. For objects that are created directly from
1800 an item in the input file, you can use the @code{\tweak} command.
1803 @lilypond[relative=2,verbatim,quote]
1808 \tweak #'duration-log #1
1811 -\tweak #'padding #8
1817 But the main use of the @code{\tweak} command is to modify just
1818 one of a number of notation elements which start at the same musical
1819 moment, like the notes of a chord, or tuplet brackets which start
1822 The @code{\tweak} command sets a property in the following object
1823 directly, without requiring the grob name or context to be
1824 specified. For this to work, it is necessary for the @code{\tweak}
1825 command to remain immediately adjacent to the object to which it is
1826 to apply after the input file has been converted to a music stream.
1827 This is often not the case, as many additional elements are inserted
1828 into the music stream implicitly. For example, when a note which is
1829 not part of a chord is processed, LilyPond implicitly inserts a
1830 @code{ChordEvent} event before the note, so separating the tweak
1831 from the note. However, if chord symbols are placed round the
1832 tweak and the note, the @code{\tweak} command comes after the
1833 @code{ChordEvent} in the music stream, so remaining adjacent to the
1834 note, and able to modify it.
1838 @lilypond[relative=2,verbatim,quote]
1839 <\tweak #'color #red c>4
1845 @lilypond[relative=2,verbatim,quote]
1846 \tweak #'color #red c4
1851 For an introduction to the syntax and uses of the tweak command
1852 see @rlearning{Tweaking methods}.
1854 When several similar items are placed at the same musical moment,
1855 the @code{\override} command cannot be used to modify just one of
1856 them -- this is where the @code{\tweak} command must be used.
1857 Items which may appear more than once at the same musical moment
1858 include the following:
1860 @c TODO expand to include any further uses of \tweak
1862 @item note heads of notes inside a chord
1863 @item articulation signs on a single note
1864 @item ties between notes in a chord
1865 @item tuplet brackets starting at the same time
1868 @c TODO add examples of these
1870 @cindex chord, modifying one note in
1872 In this example, the color of one note head and the type of another
1873 note head are modified within a single chord:
1875 @lilypond[relative=2,verbatim,quote]
1880 \tweak #'duration-log #1
1885 @code{\tweak} can be used to modify slurs:
1887 @lilypond[verbatim,quote,relative=1]
1888 c-\tweak #'thickness #5 ( d e f)
1892 For the @code{\tweak} command to work, it must
1893 remain immediately adjacent to the object to which it is
1894 to apply after the input file has been converted to a music stream.
1895 At times, LilyPond may insert additional items into the music stream
1896 during the parsing process. For example, when a note that is not
1897 explicitly part of a chord will be placed in a chord by LilyPond,
1898 so notes to be modified with @code{\tweak} must be placed inside
1901 @lilypond[relative=2,verbatim,quote]
1902 \tweak #'color #red c4
1903 <\tweak #'color #red c>4
1906 The @code{\tweak} command cannot be used to modify any item
1907 that does not appear explicitly in the input file. In particular
1908 it cannot be used to modify stems,
1909 beams or accidentals directly, since these are generated later by
1910 note heads, rather than by music elements in the input stream.
1911 Nor can @code{\tweak} be used to modify clefs or time
1912 signatures, since these become separated from any preceding
1913 @code{\tweak} command in the input stream by the automatic
1914 insertion of extra elements required to specify the context.
1916 Several @code{\tweak} commands may be placed before a
1917 notational element -- all affect it:
1919 @lilypond[verbatim,quote,relative=1]
1921 -\tweak #'style #'dashed-line
1922 -\tweak #'dash-fraction #0.2
1923 -\tweak #'thickness #3
1924 -\tweak #'color #red
1929 The music stream which is generated from a section of an input file,
1930 including any automatically inserted elements, may be examined,
1931 see @rextend{Displaying music expressions}. This may be helpful in
1932 determining what may be modified by a @code{\tweak} command, or
1933 in determining how to adjust the input to make a @code{\tweak}
1939 @rlearning{Tweaking methods}.
1942 @rextend{Displaying music expressions}.
1947 @cindex tweaks in a variable
1948 The @code{\tweak} command cannot be used inside a variable.
1950 @cindex tweaks in lyrics
1951 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1953 @cindex tweaking control points
1954 @cindex control points, tweaking
1956 The @code{\tweak} command will apply to only the first of several
1957 generated ties in a chord.
1959 @node set versus override
1960 @subsection @code{\set} vs. @code{\override}
1962 TODO -- This section is probably unnecessary now.
1965 We have seen two methods of changing properties: @code{\set} and
1966 @code{\override}. There are actually two different kinds of
1969 @code{fontSize} is a special property: it is equivalent to
1970 entering @code{\override ... #'font-size} for all pertinent
1971 objects. Since this is a common change, the special
1972 property (modified with @code{\set}) was created.
1976 @node Useful concepts and properties
1977 @section Useful concepts and properties
1982 * Direction and placement::
1983 * Context layout order::
1984 * Distances and measurements::
1985 * Staff symbol properties::
1987 * Visibility of objects::
1989 * Rotating objects::
1993 @subsection Input modes
1995 The way in which the notation contained within an input file is
1996 interpreted is determined by the current input mode.
2000 This is activated with the @code{\chordmode} command, and causes
2001 input to be interpreted with the syntax of chord notation, see
2002 @ref{Chord notation}. Chords are rendered as notes on a staff.
2004 Chord mode is also activated with the @code{\chords} command.
2005 This also creates a new @code{ChordNames} context and
2006 causes the following input to be interpreted with the syntax of
2007 chord notation and rendered as chord names in the @code{ChordNames}
2008 context, see @ref{Printing chord names}.
2012 This is activated with the @code{\drummode} command, and causes
2013 input to be interpreted with the syntax of drum notation, see
2014 @ref{Basic percussion notation}.
2016 Drum mode is also activated with the @code{\drums} command.
2017 This also creates a new @code{DrumStaff} context and causes the
2018 following input to be interpreted with the syntax of drum notation
2019 and rendered as drum symbols on a drum staff, see @ref{Basic
2020 percussion notation}.
2022 @strong{Figure mode}
2024 This is activated with the @code{\figuremode} command, and causes
2025 input to be interpreted with the syntax of figured bass, see
2026 @ref{Entering figured bass}.
2028 Figure mode is also activated with the @code{\figures} command.
2029 This also creates a new @code{FiguredBass} context and causes the
2030 following input to be interpreted with the figured bass syntax
2031 and rendered as figured bass symbols in the @code{FiguredBass}
2032 context, see @ref{Introduction to figured bass}.
2034 @strong{Fret and tab modes}
2036 There are no special input modes for entering fret and tab symbols.
2038 To create tab diagrams, enter notes or chords in note mode and
2039 render them in a @code{TabStaff} context, see
2040 @ref{Default tablatures}.
2042 To create fret diagrams above a staff, you have two choices.
2043 You can either use the @code{FretBoards} context (see
2044 @ref{Automatic fret diagrams} or you can enter them as a markup
2045 above the notes using the @code{\fret-diagram} command (see
2046 @ref{Fret diagram markups}).
2048 @strong{Lyrics mode}
2050 This is activated with the @code{\lyricmode} command, and causes
2051 input to be interpreted as lyric syllables with optional durations
2052 and associated lyric modifiers, see @ref{Vocal music}.
2054 Lyric mode is also activated with the @code{\addlyrics} command.
2055 This also creates a new @code{Lyrics} context and an implicit
2056 @code{\lyricsto} command which associates the following lyrics
2057 with the preceding music.
2059 @strong{Markup mode}
2061 This is activated with the @code{\markup} command, and causes
2062 input to be interpreted with the syntax of markup, see
2063 @ref{Text markup commands}.
2065 @c silly work-around for texinfo broken-ness
2066 @c (@strong{Note...} causes a spurious cross-reference in Info)
2069 This is the default mode or it may be activated with the
2070 @code{\notemode} command. Input is interpreted as pitches,
2071 durations, markup, etc and typeset as musical notation on a staff.
2073 It is not normally necessary to specify note mode explicitly, but
2074 it may be useful to do so in certain situations, for example if you
2075 are in lyric mode, chord mode or any other mode and want to insert
2076 something that only can be done with note mode syntax.
2078 For example, to indicate dynamic markings for the verses of a
2079 choral pieces it is necessary to enter note mode to interpret
2082 @lilypond[verbatim,relative=2,quote]
2085 \notemode{\set stanza = \markup{ \dynamic f 1. } }
2089 \notemode{\set stanza = \markup{ \dynamic p 2. } }
2096 @node Direction and placement
2097 @subsection Direction and placement
2099 In typesetting music the direction and placement of many items is
2100 a matter of choice. For example, the stems of notes can
2101 be directed up or down; lyrics, dynamics, and other expressive
2102 marks may be placed above or below the staff; text may be aligned
2103 left, right or center; etc. Most of these choices may be left to
2104 be determined automatically by LilyPond, but in some cases it may
2105 be desirable to force a particular direction or placement.
2107 @strong{Articulation direction indicators}
2109 By default some directions are always up or always down (e.g.
2110 dynamics or fermata), while other things can alternate between
2111 up or down based on the stem direction (like slurs or accents).
2113 @c TODO Add table showing these
2115 The default action may be overridden by prefixing the articulation
2116 by a @emph{direction indicator}. Three direction indicators are
2117 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
2118 and @code{-} (meaning @qq{use default direction}). The direction
2119 indicator can usually be omitted, in which case @code{-} is assumed,
2120 but a direction indicator is @strong{always} required before
2123 @item @code{\tweak} commands
2124 @item @code{\markup} commands
2125 @item @code{\tag} commands
2126 @item string markups, e.g. -"string"
2127 @item fingering instructions, e.g. @code{-1}
2128 @item articulation shortcuts, e.g. @code{-.}, @code{->}, @code{--}
2131 Direction indicators affect only the next note:
2133 @lilypond[verbatim,quote,relative=2]
2140 @strong{The direction property}
2142 The position or direction of many layout objects is controlled
2143 by the @code{direction} property.
2145 The value of the @code{direction} property may be
2146 set to @code{1}, meaning @qq{up} or @qq{above}, or to @code{-1},
2147 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
2148 @code{DOWN} may be used instead of @code{1} and @code{-1}
2149 respectively. The default direction may be specified by setting
2150 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
2151 in many cases predefined commands
2152 exist to specify the direction. These are all of the form
2155 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
2158 where @code{xxxNeutral} means @qq{use the default direction}.
2159 See @rlearning{Within-staff objects}.
2161 In a few cases, arpeggio being the only common example, the value
2162 of the @code{direction} property specifies whether the object
2163 is to be placed to the right or left of the parent object. In
2164 this case @code{-1} or @code{LEFT} means @qq{to the left} and
2165 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
2166 or @code{CENTER} means @qq{use the default} direction, as before.
2169 These all have side-axis set to #X
2170 AmbitusAccidental - direction has no effect
2172 StanzaNumber - not tried
2173 TrillPitchAccidental - not tried
2174 TrillPitchGroup - not tried
2177 These indications affect all notes until they are cancelled.
2179 @lilypond[verbatim,quote,relative=2]
2189 @node Context layout order
2190 @subsection Context layout order
2192 @cindex contexts, layout order
2194 Contexts are normally positioned in a system from top to bottom
2195 in the order in which they are encountered in the input file. When
2196 contexts are nested, the outer context will include inner nested
2197 contexts as specified in the input file, provided the inner contexts
2198 are included in the outer context's @qq{accepts} list. Nested
2199 contexts which are not included in the outer context's @qq{accepts}
2200 list will be repositioned below the outer context rather than nested
2203 Note that a context will be silently created implicitly if a command
2204 is encountered when there is no suitable context available to
2205 contain it. This can give rise to unexpected new staves or scores.
2207 The default order in which contexts are laid out and the
2208 @qq{accepts} list can be changed, see @ref{Aligning contexts}.
2212 @rprogram{An extra staff appears}.
2215 @node Distances and measurements
2216 @subsection Distances and measurements
2218 @cindex distances, absolute
2219 @cindex distances, scaled
2226 Distances in LilyPond are of two types: absolute and scaled.
2228 Absolute distances are used for specifying margins, indents, and
2229 other page layout details, and are by default specified in
2230 millimeters. Distances may be specified in other units by
2231 following the quantity by @code{\mm}, @code{\cm},
2232 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27
2233 of an inch). Page layout distances can also be specified in
2234 scalable units (see the following paragraph) by appending
2235 @code{\staff-space} to the quantity.
2236 Page layout is described in detail in @ref{Page formatting}.
2238 Scaled distances are always specified in units of the staff-space
2239 or, rarely, the half staff-space. The staff-space is the distance
2240 between two adjacent staff lines. The default value can be changed
2241 globally by setting the global staff size, or it can be overridden
2242 locally by changing the @code{staff-space} property of
2243 @code{StaffSymbol}. Scaled distances automatically scale with any
2244 change to the either the global staff size or the
2245 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2246 automatically only with changes to the global staff size.
2247 The global staff size thus enables the overall size of a rendered
2248 score to be easily varied. For the methods of setting the global
2249 staff size see @ref{Setting the staff size}.
2253 If just a section of a score needs to be rendered to a different
2254 scale, for example an ossia section or a footnote, the global staff
2255 size cannot simply be changed as this would affect the entire score.
2256 In such cases the change in size is made by overriding both the
2257 @code{staff-space} property of @code{StaffSymbol} and the size of
2258 the fonts. A Scheme function, @code{magstep}, is available to
2259 convert from a font size change to the equivalent change in
2260 @code{staff-space}. For an explanation and an example of its use,
2261 see @rlearning{Length and thickness of objects}.
2266 @rlearning{Length and thickness of objects}.
2269 @ref{Page formatting},
2270 @ref{Setting the staff size}.
2273 @node Staff symbol properties
2274 @subsection Staff symbol properties
2276 @cindex adjusting staff symbol
2277 @cindex drawing staff symbol
2278 @cindex staff symbol, setting of
2280 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2281 @c Need to think of uses for these properties. Eg 'line-positions
2282 @c is used in a snippet to thicken centre line.
2283 @c If retained, add @ref to here in 1.6.2 -td
2285 The vertical position of staff lines and the number of staff lines
2286 can be defined at the same time. As the following example shows,
2287 note positions are not influenced by the staff line positions.
2289 @warning{The @code{'line-positions} property overrides the
2290 @code{'line-count} property. The number of staff lines is
2291 implicitly defined by the number of elements in the list of values
2292 for @code{'line-positions}.}
2294 @lilypond[verbatim,quote,relative=1]
2296 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
2301 The width of a staff can be modified. The units are staff
2302 spaces. The spacing of objects inside the staff is not affected by
2305 @lilypond[verbatim,quote,relative=1]
2307 \override StaffSymbol #'width = #23
2314 @subsection Spanners
2316 Many objects of musical notation extend over several notes or even
2317 several bars. Examples are slurs, beams, tuplet brackets, volta
2318 repeat brackets, crescendi, trills, and glissandi. Such objects
2319 are collectively called @qq{spanners}, and have special properties to control
2320 their appearance and behaviour. Some of these properties are common
2321 to all spanners; others are restricted to a sub-set of the spanners.
2323 All spanners support the @code{spanner-interface}. A few, esentially
2324 those that draw a straight line between the two objects, support in
2325 addition the @code{line-spanner-interface}.
2327 @unnumberedsubsubsec Using the @code{spanner-interface}
2329 This interface provides two properties that apply to several spanners.
2331 @strong{@i{The @code{minimum-length} property}}
2333 The minimum length of the spanner is specified by the
2334 @code{minimum-length} property. Increasing this usually has the
2335 necessary effect of increasing the spacing of the notes between the
2336 two end points. However, this override has no effect on
2337 many spanners, as their length is determined by other considerations.
2338 A few examples where it is effective are shown below.
2348 Works as long as callback is made:
2352 Works not at all for:
2361 @lilypond[verbatim,quote,relative=2]
2364 % increase the length of the tie
2365 -\tweak #'minimum-length #5
2369 @lilypond[verbatim,quote,relative=2]
2371 \compressFullBarRests
2373 % increase the length of the rest bar
2374 \once \override MultiMeasureRest #'minimum-length = #20
2379 @lilypond[verbatim,quote,relative=2]
2381 % increase the length of the hairpin
2382 \override Hairpin #'minimum-length = #20
2386 This override can also be used to increase the length of slurs and
2389 @lilypond[verbatim,quote,relative=2]
2392 -\tweak #'minimum-length #5
2397 -\tweak #'minimum-length #5
2401 For some layout objects, the @code{minimum-length} property becomes
2402 effective only if the @code{set-spacing-rods} procedure is called
2403 explicitly. To do this, the @code{springs-and-rods} property should
2404 be set to @code{ly:spanner::set-spacing-rods}. For example,
2405 the minimum length of a glissando has no effect unless the
2406 @code{springs-and-rods} property is set:
2408 @lilypond[verbatim,quote,relative=1]
2412 % not effective alone
2413 \once \override Glissando #'minimum-length = #20
2416 % effective only when both overrides are present
2417 \once \override Glissando #'minimum-length = #20
2418 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2422 The same is true of the @code{Beam} object:
2424 @lilypond[verbatim,quote,relative=1]
2425 % not effective alone
2426 \once \override Beam #'minimum-length = #20
2429 % effective only when both overrides are present
2430 \once \override Beam #'minimum-length = #20
2431 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2435 @strong{@i{The @code{to-barline} property}}
2437 The second useful property of the @code{spanner-interface} is
2438 @code{to-barline}. By default this is true, causing hairpins and
2439 other spanners which are terminated on the first note of a measure to
2440 end instead on the immediately preceding bar line. If set to false,
2441 the spanner will extend beyond the bar line and end on the note
2444 @lilypond[verbatim,quote,relative=2]
2445 a \< a a a a \! a a a \break
2446 \override Hairpin #'to-barline = ##f
2447 a \< a a a a \! a a a
2450 This property is not effective for all spanners. For example,
2451 seting it to @code{#t} has no effect on slurs or phrasing slurs
2452 or on other spanners for which terminating on the bar line would
2455 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2457 Objects which support the @code{line-spanner-interface} include
2460 @item @code{DynamicTextSpanner}
2461 @item @code{Glissando}
2462 @item @code{TextSpanner}
2463 @item @code{TrillSpanner}
2464 @item @code{VoiceFollower}
2467 The routine responsible for drawing the stencils for these spanners is
2468 @code{ly:line-interface::print}. This routine determines the
2469 exact location of the two end points and draws a line
2470 between them, in the style requested. The locations of the two
2471 end points of the spanner are computed on-the-fly, but it is
2472 possible to override their Y-coordinates. The
2473 properties which need to be specified are nested
2474 two levels down within the property hierarchy, but the syntax of
2475 the @code{\override} command is quite simple:
2477 @lilypond[relative=2,quote,verbatim]
2479 \once \override Glissando #'(bound-details left Y) = #3
2480 \once \override Glissando #'(bound-details right Y) = #-2
2484 The units for the @code{Y} property are @code{staff-space}s,
2485 with the center line of the staff being the zero point.
2486 For the glissando, this is the value for @code{Y} at the
2487 X-coordinate corresponding to the center point of each note head,
2488 if the line is imagined to be extended to there.
2490 If @code{Y} is not set, the value is computed from the vertical
2491 position of the corresponding attachment point of the spanner.
2493 In case of a line break, the values for the end points are
2494 specified by the @code{left-broken} and @code{right-broken}
2495 sub-lists of @code{bound-details}. For example:
2497 @lilypond[relative=2,ragged-right,verbatim,fragment]
2498 \override Glissando #'breakable = ##t
2499 \override Glissando #'(bound-details right-broken Y) = #-3
2500 c1 \glissando \break
2505 A number of further properties of the @code{left} and
2506 @code{right} sub-lists of the @code{bound-details} property
2507 may be modified in the same way as @code{Y}:
2511 This sets the Y-coordinate of the end point, in @code{staff-space}s
2512 offset from the staff center line. By default, it is the center of
2513 the bound object, so a glissando points to the vertical center of
2516 For horizontal spanners, such as text spanners and trill spanners,
2517 it is hardcoded to 0.
2520 This determines where the line starts and ends in the X-direction,
2521 relative to the bound object. So, a value of @code{-1} (or
2522 @code{LEFT}) makes the line start/end at the left side of the note
2523 head it is attached to.
2526 This is the absolute X-coordinate of the end point. It is usually
2527 computed on the fly, and overriding it has little useful effect.
2530 Line spanners may have symbols at the beginning or end, which is
2531 contained in this sub-property. This is for internal use; it is
2532 recommended that @code{text} be used instead.
2535 This is a markup that is evaluated to yield the stencil. It is used
2536 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2538 @lilypond[quote,ragged-right,fragment,relative=2,verbatim]
2539 \override TextSpanner #'(bound-details left text)
2540 = \markup { \small \bold Slower }
2541 c2\startTextSpan b c a\stopTextSpan
2544 @item stencil-align-dir-y
2545 @item stencil-offset
2546 Without setting one of these, the stencil is simply put at the
2547 end-point, centered on the line, as defined by the @code{X} and
2548 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2549 or @code{stencil-offset} will move the symbol at the edge vertically
2550 relative to the end point of the line:
2552 @lilypond[relative=1,fragment,verbatim]
2553 \override TextSpanner
2554 #'(bound-details left stencil-align-dir-y) = #-2
2555 \override TextSpanner
2556 #'(bound-details right stencil-align-dir-y) = #UP
2558 \override TextSpanner
2559 #'(bound-details left text) = #"ggg"
2560 \override TextSpanner
2561 #'(bound-details right text) = #"hhh"
2562 c4^\startTextSpan c c c \stopTextSpan
2565 Note that negative values move the text @emph{up}, contrary to the
2566 effect that might be expected, as a value of @code{-1} or
2567 @code{DOWN} means align the @emph{bottom} edge of the text with
2568 the spanner line. A value of @code{1} or @code{UP} aligns
2569 the top edge of the text with the spanner line.
2572 Setting this sub-property to @code{#t} produces an arrowhead at the
2576 This sub-property controls the space between the specified
2577 end point of the line and the actual end. Without padding, a
2578 glissando would start and end in the center of each note head.
2582 The music function @code{\endSpanners} terminates the spanner
2583 which starts on the immediately following note prematurely. It
2584 is terminated after exactly one note, or at the following bar line
2585 if @code{to-barline} is true and a bar line occurs before the next
2588 @lilypond[verbatim,quote,ragged-right,relative=2,fragment]
2590 c2 \startTextSpan c2 c2
2595 When using @code{\endSpanners} it is not necessary to close
2596 \startTextSpan with \stopTextSpan, nor is it necessary to close
2597 hairpins with @code{\!}.
2601 Internals Reference:
2602 @rinternals{TextSpanner},
2603 @rinternals{Glissando},
2604 @rinternals{VoiceFollower},
2605 @rinternals{TrillSpanner},
2606 @rinternals{line-spanner-interface}.
2609 @node Visibility of objects
2610 @subsection Visibility of objects
2612 @cindex objects, visibility of
2613 @cindex grobs, visibility of
2614 @cindex visibility of objects
2616 There are four main ways in which the visibility of layout objects
2617 can be controlled: their stencil can be removed, they can be made
2618 transparent, they can be colored white, or their
2619 @code{break-visibility} property can be overridden. The first
2620 three apply to all layout objects; the last to just a few -- the
2621 @emph{breakable} objects. The Learning Manual introduces these
2622 four techniques, see @rlearning{Visibility and color of objects}.
2624 There are also a few other techniques which are specific to
2625 certain layout objects. These are covered under Special
2629 * Removing the stencil::
2630 * Making objects transparent::
2631 * Painting objects white::
2632 * Using break-visibility::
2633 * Special considerations::
2637 @node Removing the stencil
2638 @unnumberedsubsubsec Removing the stencil
2640 @cindex stencil, removing
2642 Every layout object has a stencil property. By default this is set
2643 to the specific function which draws that object. If this property
2644 is overridden to @code{#f} no function will be called and the object
2645 will not be drawn. The default action can be recovered with
2648 @lilypond[quote,verbatim,relative=1]
2650 \override Score.BarLine #'stencil = ##f
2652 \revert Score.BarLine #'stencil
2656 @node Making objects transparent
2657 @unnumberedsubsubsec Making objects transparent
2659 @cindex transparent, making objects
2661 Every layout object has a transparent property which by default is
2662 set to @code{#f}. If set to @code{#t} the object still occupies
2663 space but is made invisible.
2665 @lilypond[quote,verbatim,relative=2]
2667 \once \override NoteHead #'transparent = ##t
2671 @node Painting objects white
2672 @unnumberedsubsubsec Painting objects white
2674 @cindex objects, coloring
2675 @cindex coloring objects
2677 @cindex printing order
2678 @cindex overwriting objects
2679 @cindex objects, overwriting
2680 @cindex grobs, overwriting
2682 Every layout object has a color property which by default is set
2683 to @code{black}. If this is overridden to @code{white} the object
2684 will be indistinguishable from the white background. However,
2685 if the object crosses other objects the color of the crossing
2686 points will be determined by the order in which they are drawn,
2687 and this may leave a ghostly image of the white object, as shown
2690 @lilypond[quote,verbatim,relative=2]
2691 \override Staff.Clef #'color = #white
2695 This may be avoided by changing the order of printing the objects.
2696 All layout objects have a @code{layer} property which should be set
2697 to an integer. Objects with the lowest value of @code{layer} are
2698 drawn first, then objects with progressively higher values are drawn,
2699 so objects with higher values overwrite objects with lower values.
2700 By default most objects are assigned a @code{layer} value of
2701 @code{1}, although a few objects, including @code{StaffSymbol} and
2702 @code{BarLine}, are assigned a value of @code{0}. The order of
2703 printing objects with the same value of @code{layer} is indeterminate.
2705 In the example above the white clef, with a default @code{layer}
2706 value of @code{1}, is drawn after the staff lines (default
2707 @code{layer} value @code{0}), so overwriting them. To change this,
2708 the @code{Clef} object must be given in a lower value of
2709 @code{layer}, say @code{-1}, so that it is drawn earlier:
2711 @lilypond[quote,verbatim,relative=2]
2712 \override Staff.Clef #'color = #white
2713 \override Staff.Clef #'layer = #-1
2717 @node Using break-visibility
2718 @unnumberedsubsubsec Using break-visibility
2720 @c TODO Add making other objects breakable
2722 @cindex break-visibility
2724 Most layout objects are printed only once, but some like
2725 bar lines, clefs, time signatures and key signatures, may need
2726 to be printed twice when a line break occurs -- once at the end
2727 of the line and again at the start of the next line. Such
2728 objects are called @emph{breakable}, and have a property, the
2729 @code{break-visibility} property to control their visibility
2730 at the three positions in which they may appear -- at the
2731 start of a line, within a line if they are changed, and at the
2732 end of a line if a change takes place there.
2734 For example, the time signature
2735 by default will be printed at the start of the first line, but
2736 nowhere else unless it changes, when it will be printed at the
2737 point at which the change occurs. If this change occurs at the
2738 end of a line the new time signature will be printed at the start
2739 of the next line and a cautionary time signature will be printed
2740 at the end of the previous line as well.
2742 This behaviour is controlled by the @code{break-visibility}
2743 property, which is explained in
2744 @c Leave this ref on a newline - formats incorrectly otherwise -td
2745 @rlearning{Visibility and color of objects}. This property takes
2746 a vector of three booleans which, in order, determine whether the
2747 object is printed at the end of, within the body of, or at the
2748 beginning of a line. Or to be more precise, before a line break,
2749 where there is no line break, or after a line break.
2751 Alternatively, these eight combinations may be specified
2752 by pre-defined functions, defined in @file{scm/@/output@/-lib@/.scm},
2753 where the last three columns indicate whether the layout objects
2754 will be visible in the positions shown at the head of the columns:
2756 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2757 @headitem Function @tab Vector @tab Before @tab At no @tab After
2758 @headitem form @tab form @tab break @tab break @tab break
2760 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2761 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2762 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2763 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2764 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2765 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2766 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2767 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2770 The default settings of @code{break-visibility} depend on the
2771 layout object. The following table shows all the layout objects
2772 of interest which are affected by @code{break-visibility} and the
2773 default setting of this property:
2775 @multitable @columnfractions .3 .3 .4
2777 @headitem Layout object @tab Usual context @tab Default setting
2779 @c omit Ambitus as it appears not to be affected by break-visibility -td
2780 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2781 @item @code{BarLine} @tab @code{Score} @tab calculated
2782 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2783 @c omit the following item until it can be explained -td
2784 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2785 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2786 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2787 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2788 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2789 @c omit KeyCancellation until it can be explained -td
2790 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2791 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2792 @c omit LeftEdge until it can be explained -td
2793 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2794 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2795 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2796 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2800 The example below shows the use of the vector form to control the
2801 visibility of barlines:
2803 @lilypond[quote,verbatim,relative=1,ragged-right]
2806 % Remove bar line at the end of the current line
2807 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2813 Although all three components of the vector used to override
2814 @code{break-visibility} must be present, not all of them are
2815 effective with every layout object, and some combinations may
2816 even give errors. The following limitations apply:
2819 @item Bar lines cannot be printed at start of line.
2820 @item A bar number cannot be printed at the start of the first
2821 line unless it is set to be different from 1.
2822 @item Clef -- see below
2823 @item Double percent repeats are either all printed or all
2824 suppressed. Use begin-of line-invisible to print and
2825 all-invisible to suppress.
2826 @item Key signature -- see below
2827 @item OctavateEight -- see below
2830 @node Special considerations
2831 @unnumberedsubsubsec Special considerations
2833 @strong{@emph{Visibility following explicit changes}}
2835 @cindex key signature, visibility following explicit change
2836 @cindex explicitKeySignatureVisibility
2837 @cindex clef, visibility following explicit change
2838 @cindex explicitClefVisibility
2840 The @code{break-visibility} property controls the visibility of
2841 key signatures and changes of clef only at the start of lines,
2842 i.e. after a break. It has no effect on the visibility of the
2843 key signature or clef following an explicit key change or an
2844 explicit clef change within or at the end of a line. In the
2845 following example the key signature following the explicit change
2846 to B-flat major is still visible, even though @code{all-invisible}
2849 @lilypond[quote,verbatim,relative=1,ragged-right]
2852 % Try to remove all key signatures
2853 \override Staff.KeySignature #'break-visibility = #all-invisible
2861 The visibility of such explicit key signature and clef changes is
2862 controlled by the @code{explicitKeySignatureVisibility} and
2863 @code{explicitClefVisibility} properties. These are the equivalent
2864 of the @code{break-visibility} property and both take a vector of
2865 three booleans or the predefined functions listed above, exactly like
2866 @code{break-visibility}. Both are properties of the Staff context,
2867 not the layout objects themselves, and so they are set using the
2868 @code{\set} command. Both are set by default to @code{all-visible}.
2869 These properties control only the visibility of key signatures and
2870 clefs resulting from explicit changes and do not affect key
2871 signatures and clefs at the beginning of lines;
2872 @code{break-visibility} must still be overridden in the appropriate
2873 object to remove these.
2875 @lilypond[quote,verbatim,relative=1,ragged-right]
2878 \set Staff.explicitKeySignatureVisibility = #all-invisible
2879 \override Staff.KeySignature #'break-visibility = #all-invisible
2886 @strong{@emph{Visibility of cautionary accidentals}}
2888 To remove the cautionary accidentals printed at an explicit key
2889 change, set the Staff context property @code{printKeyCancellation}
2892 @lilypond[quote,verbatim,relative=1,ragged-right]
2895 \set Staff.explicitKeySignatureVisibility = #all-invisible
2896 \set Staff.printKeyCancellation = ##f
2897 \override Staff.KeySignature #'break-visibility = #all-invisible
2904 With these overrides only the accidentals before the notes remain
2905 to indicate the change of key.
2907 @c TODO Add visibility of cautionary accidentals before notes
2909 @strong{@emph{Automatic bars}}
2911 @cindex automaticBars
2912 @cindex bar lines, suppressing
2914 As a special case, the printing of bar lines can also be turned off
2915 by setting the @code{automaticBars} property in the Score context.
2916 If set to @code{#f}, bar lines will not be printed automatically;
2917 they must be explicitly created with a @code{\bar} command. Unlike
2918 the @code{\cadenzaOn} predefined command, measures are still counted.
2919 Bar generation will resume according to that count if this property
2920 is later set to @code{#t}. When set to @code{#f}, line breaks can
2921 occur only at explicit @code{\bar} commands.
2925 @strong{@emph{Octavated clefs}}
2927 @cindex octavated clefs, visibility of
2928 @cindex visibility of octavated clefs
2929 @cindex clefs, visibility of octavation
2931 The small octavation symbol on octavated clefs is produced by the
2932 @code{OctavateEight} layout object. Its visibility is controlled
2933 independently from that of the @code{Clef} object, so it is
2934 necessary to apply any required @code{break-visibility} overrides
2935 to both the @code{Clef} and the @code{OctavateEight} layout objects
2936 to fully suppress such clef symbols at the start of each line.
2938 For explicit clef changes, the @code{explicitClefVisibility}
2939 property controls both the clef symbol and any octavation symbol
2945 @rlearning{Visibility and color of objects}
2949 @subsection Line styles
2951 Some performance indications, e.g., @i{rallentando} and
2952 @i{accelerando} and @i{trills} are written as text and are
2953 extended over many measures with lines, sometimes dotted or wavy.
2955 These all use the same routines as the glissando for drawing the
2956 texts and the lines, and tuning their behavior is therefore also
2957 done in the same way. It is done with a spanner, and the routine
2958 responsible for drawing the spanners is
2959 @code{ly:line-interface::print}. This routine determines the
2960 exact location of the two @i{span points} and draws a line
2961 between them, in the style requested.
2963 Here is an example showing the different line styles available,
2964 and how to tune them.
2966 @lilypond[relative=2,ragged-right,verbatim,fragment]
2968 \once \override Glissando #'style = #'dashed-line
2970 \override Glissando #'style = #'dotted-line
2972 \override Glissando #'style = #'zigzag
2974 \override Glissando #'style = #'trill
2978 The locations of the end-points of the spanner are computed
2979 on-the-fly for every graphic object, but it is possible to
2983 @lilypond[relative=2,ragged-right,verbatim,fragment]
2985 \once \override Glissando #'(bound-details right Y) = #-2
2989 The value for @code{Y} is set to @code{-2} for the right end
2990 point. The left side may be similarly adjusted by specifying
2991 @code{left} instead of @code{right}.
2993 If @code{Y} is not set, the value is computed from the vertical
2994 position of the left and right attachment points of the spanner.
2996 Other adjustments of spanners are possible, for details, see
2999 @node Rotating objects
3000 @subsection Rotating objects
3002 Both layout objects and elements of markup text can be rotated by
3003 any angle about any point, but the method of doing so differs.
3006 * Rotating layout objects::
3010 @node Rotating layout objects
3011 @unnumberedsubsubsec Rotating layout objects
3013 @cindex rotating objects
3014 @cindex objects, rotating
3016 All layout objects which support the @code{grob-interface} can be
3017 rotated by setting their @code{rotation} property. This takes a
3018 list of three items: the angle of rotation counter-clockwise,
3019 and the x and y coordinates of the point relative to the object's
3020 reference point about which the rotation is to be performed. The
3021 angle of rotation is specified in degrees and the coordinates in
3024 The angle of rotation and the coordinates of the rotation point must
3025 be determined by trial and error.
3027 @cindex hairpins, angled
3028 @cindex angled hairpins
3030 There are only a few situations where the rotation of layout
3031 objects is useful; the following example shows one situation where
3034 @lilypond[quote,verbatim,relative=1]
3036 \override Hairpin #'rotation = #'(20 -1 0)
3040 @node Rotating markup
3041 @unnumberedsubsubsec Rotating markup
3043 All markup text can be rotated to lie at any angle by prefixing it
3044 with the @code{\rotate} command. The command takes two arguments:
3045 the angle of rotation in degrees counter-clockwise and the text to
3046 be rotated. The extents of the text are not rotated: they take
3047 their values from the extremes of the x and y coordinates of the
3048 rotated text. In the following example the
3049 @code{outside-staff-priority} property for text is set to @code{#f}
3050 to disable the automatic collision avoidance, which would push some
3051 of the text too high.
3053 @lilypond[quote,verbatim,relative=1]
3054 \override TextScript #'outside-staff-priority = ##f
3055 g4^\markup { \rotate #30 "a G" }
3056 b^\markup { \rotate #30 "a B" }
3057 des^\markup { \rotate #30 "a D-Flat" }
3058 fis^\markup { \rotate #30 "an F-Sharp" }
3061 @node Advanced tweaks
3062 @section Advanced tweaks
3064 This section discusses various approaches to fine tuning the
3065 appearance of the printed score.
3068 * Aligning objects::
3069 * Vertical grouping of grobs::
3070 * Modifying stencils::
3071 * Modifying shapes::
3077 @rlearning{Tweaking output},
3078 @rlearning{Other sources of information}.
3081 @ref{Explaining the Internals Reference},
3082 @ref{Modifying properties}.
3085 @file{scm/@/define@/-grobs@/.scm}.
3088 @rlsr{Tweaks and overrides}.
3091 @rextend{Interfaces for programmers}.
3093 Internals Reference:
3094 @rinternals{All layout objects}.
3097 @node Aligning objects
3098 @subsection Aligning objects
3100 Graphical objects which support the @code{self-alignment-interface} and/or
3101 the @code{side-position-interface} can be
3102 aligned to a previously placed object in a variety of ways. For a list of these objects, see
3103 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
3105 All graphical objects have a reference point, a horizontal extent and a
3106 vertical extent. The horizontal extent is a pair of numbers
3107 giving the displacements from the reference point of the left and
3108 right edges, displacements to the left being negative. The
3109 vertical extent is a pair of numbers giving the displacement from
3110 the reference point to the bottom and top edges, displacements down
3113 An object's position on a staff is given by the values of the
3114 @code{X-offset} and @code{Y-offset} properties. The value of
3115 @code{X-offset} gives the displacement from the x coordinate of
3116 the reference point of the parent object, and the value of
3117 @code{Y-offset} gives the displacement from the center line of the
3118 staff. The values of @code{X-offset} and
3119 @code{Y-offset} may be set directly or may be set to be calculated
3120 by procedures in order to achieve alignment with the parent object
3123 @warning{Many objects have special positioning considerations which
3124 cause any setting of @code{X-offset} or @code{Y-offset} to be
3125 ignored or modified, even though the object supports the
3126 @code{self-alignment-interface}.}
3128 For example, an accidental can be repositioned
3129 vertically by setting @code{Y-offset} but any changes to
3130 @code{X-offset} have no effect.
3132 Rehearsal marks may be aligned with
3133 breakable objects such as bar lines, clef symbols, time signature
3134 symbols and key signatures. There are special properties to be
3135 found in the @code{break-aligned-interface} for positioning rehearsal
3136 marks on such objects.
3139 * Setting @code{X-offset} and @code{Y-offset} directly::
3140 * Using the @code{side-position-interface}::
3141 * Using the @code{self-alignment-interface}::
3142 * Using the @code{break-alignable-interface}::
3145 @node Setting @code{X-offset} and @code{Y-offset} directly
3146 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
3148 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
3149 properties of many objects. The following example shows three
3150 notes with the default fingering position and the positions with @code{X-offset}
3151 and @code{Y-offset} modified.
3153 @lilypond[verbatim,quote,relative=2]
3156 -\tweak #'X-offset #0
3157 -\tweak #'Y-offset #0
3160 -\tweak #'X-offset #-1
3161 -\tweak #'Y-offset #1
3167 @node Using the @code{side-position-interface}
3168 @unnumberedsubsubsec Using the @code{side-position-interface}
3170 An object which supports the @code{side-position-interface} can be
3171 placed next to its parent object so that
3172 the specified edges of the two objects touch. The object may be
3173 placed above, below, to the right or to the left of the parent.
3174 The parent cannot be specified; it is determined by the order of
3175 elements in the input stream. Most objects have the associated
3176 note head as their parent.
3178 The values of the @code{side-axis} and @code{direction} properties
3179 determine where the object is to be placed, as follows:
3181 @c TODO add an example of each to the table
3183 @multitable @columnfractions .3 .3 .3
3184 @headitem @code{side-axis} @tab @code{direction} @tab
3185 @headitem property @tab property @tab Placement
3187 @item @code{0} @tab @code{-1} @tab left
3188 @item @code{0} @tab @code{1} @tab right
3189 @item @code{1} @tab @code{-1} @tab below
3190 @item @code{1} @tab @code{1} @tab above
3194 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
3195 the procedure @code{ly:side-position-interface::x-aligned-side}.
3196 This procedure will return the correct value of @code{X-offset} to
3197 place the object to the left or right side of the parent according
3198 to value of @code{direction}.
3200 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3201 the procedure @code{ly:side-position-interface::y-aligned-side}.
3202 This procedure will return the correct value of @code{Y-offset} to
3203 place the object to the top or bottom of the parent according
3204 to value of @code{direction}.
3206 @c TODO Add examples
3208 @node Using the @code{self-alignment-interface}
3209 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3211 @emph{Self-aligning objects horizontally}
3213 The horizontal alignment of an object which supports the
3214 @code{self-alignment-interface} is controlled by the value of
3215 the @code{self-alignment-X} property, provided the object's
3216 @code{X-offset} property is set to
3217 @code{ly:self-alignment-interface::x-aligned-on-self}.
3218 @code{self-alignment-X} may be given any
3219 real value, in units of half the total X extent of the
3220 object. Negative values move the object to the right, positive
3221 to the left. A value of @code{0} centers the object on the
3222 reference point of its parent, a value of @code{-1} aligns the
3223 left edge of the object on the reference point of its parent,
3224 and a value of @code{1} aligns the right edge of the object on the
3225 reference point of its parent. The symbols @code{LEFT},
3226 @code{CENTER} and @code{RIGHT} may be used instead of the values
3227 @code{-1, 0, 1} respectively.
3229 Normally the @code{\override} command would be used to modify the
3230 value of @code{self-alignment-X}, but the @code{\tweak} command
3231 can be used to separately align several annotations on a single
3234 @lilypond[quote,verbatim,relative=1]
3236 -\tweak #'self-alignment-X #-1
3238 -\tweak #'self-alignment-X #0
3240 -\tweak #'self-alignment-X #RIGHT
3242 -\tweak #'self-alignment-X #-2.5
3243 ^"aligned further to the right"
3246 @emph{Self-aligning objects vertically}
3248 Objects may be aligned vertically in an analogous way to aligning
3249 them horizontally if the @code{Y-offset} property is set to
3250 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3251 other mechanisms are often involved in vertical alignment: the
3252 value of @code{Y-offset} is just one variable taken into account.
3253 This may make adjusting the value of some objects tricky.
3254 The units are just half the vertical extent of the object, which
3255 is usually quite small, so quite large numbers may be required.
3256 A value of @code{-1} aligns the lower edge of the object with
3257 the reference point of the parent object, a value of @code{0}
3258 aligns the center of the object with the reference point of the
3259 parent, and a value of @code{1} aligns the top edge of the object
3260 with the reference point of the parent. The symbols @code{DOWN},
3261 @code{CENTER}, @code{UP} may be substituted for @code{-1, 0, 1}
3264 @emph{Self-aligning objects in both directions}
3266 By setting both @code{X-offset} and @code{Y-offset}, an object may
3267 be aligned in both directions simultaneously.
3269 The following example shows how to adjust a fingering mark so
3270 that it nestles close to the note head.
3272 @lilypond[quote,verbatim,relative=2]
3274 -\tweak #'self-alignment-X #0.5 % move horizontally left
3275 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
3276 -\tweak #'self-alignment-Y #-1 % move vertically up
3281 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3283 @c Cannot document as they do not seem to operate consistently on all objects -td
3284 @c TODO investigate further
3286 The @code{aligned-on-parent} procedures are used in the same way
3287 as the @code{aligned-on-self} procedures, they difference being
3288 that they permit an object to be aligned with the @emph{edges} of
3289 the parent rather than the parent's reference point. The following
3290 example shows the difference:
3294 @lilypond[verbatim,quote]
3300 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3302 @c Cannot document as they do not seem to operate consistently on all objects -td
3303 @c TODO investigate further
3307 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3309 @node Using the @code{break-alignable-interface}
3310 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3312 @cindex align to objects
3313 @cindex break-align-symbols
3315 Rehearsal marks and bar numbers may be aligned with notation
3316 objects other than bar lines. These objects include @code{ambitus},
3317 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3318 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3319 @code{time-signature}.
3321 By default, rehearsal marks and bar numbers will be horizontally
3322 centered above the object:
3324 @lilypond[verbatim,quote,relative=1]
3326 % the RehearsalMark will be centered above the Clef
3327 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
3332 % the RehearsalMark will be centered above the TimeSignature
3333 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
3341 A list of possible target alignment objects may be specified. If
3342 some of the objects are invisible at that point due to the setting
3343 of @code{break-visibility} or the explicit visibility settings for
3344 keys and clefs, the rehearsal mark or bar number is aligned to the
3345 first object in the list which is visible. If no objects in the
3346 list are visible the object is aligned to the bar line. If the bar
3347 line is invisible the object is aligned to the place where the bar
3350 @lilypond[verbatim,quote,relative=1]
3352 % the RehearsalMark will be centered above the Key Signature
3353 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3358 % the RehearsalMark will be centered above the Clef
3359 \set Staff.explicitKeySignatureVisibility = #all-invisible
3360 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3367 The alignment of the rehearsal mark relative to the notation object
3368 can be changed, as shown in the following example. In a score with
3369 multiple staves, this setting should be done for all the staves.
3371 @lilypond[verbatim,quote,relative=1]
3372 % The RehearsalMark will be centered above the KeySignature
3373 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3379 % The RehearsalMark will be aligned with the left edge of the KeySignature
3380 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3384 % The RehearsalMark will be aligned with the right edge of the KeySignature
3385 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3391 The rehearsal mark can also be offset to the right or left of the left edge
3392 by an arbitrary amount. The units are staff-spaces:
3394 @lilypond[verbatim,quote,relative=1]
3395 % The RehearsalMark will be aligned with the left edge of the KeySignature
3396 % and then shifted right by 3.5 staff-spaces
3397 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3398 \once \override Score.KeySignature #'break-align-anchor = #3.5
3402 % The RehearsalMark will be aligned with the left edge of the KeySignature
3403 % and then shifted left by 2 staff-spaces
3404 \once \override Score.KeySignature #'break-align-anchor = #-2
3411 @node Vertical grouping of grobs
3412 @subsection Vertical grouping of grobs
3414 @c TODO Expand this section
3416 The VerticalAlignment and VerticalAxisGroup grobs work together.
3417 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3418 etc. VerticalAlignment then vertically aligns the different grobs
3419 grouped together by VerticalAxisGroup. There is usually only one
3420 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3424 @node Modifying stencils
3425 @subsection Modifying stencils
3427 All layout objects have a @code{stencil} property which is part of
3428 the @code{grob-interface}. By default, this property is usually
3429 set to a function specific to the object that is tailor-made to
3430 render the symbol which represents it in the output. For example,
3431 the standard setting for the @code{stencil} property of the
3432 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3434 The standard symbol for any object can be replaced by modifying the
3435 @code{stencil} property to reference a different, specially-written,
3436 procedure. This requires a high level of knowledge of the internal
3437 workings of LilyPond, but there is an easier way which can often
3438 produce adequate results.
3440 This is to set the @code{stencil} property to the procedure which
3441 prints text -- @code{ly:text-interface::print} -- and to add a
3442 @code{text} property to the object which is set to contain the
3443 markup text which produces the required symbol. Due to the
3444 flexibility of markup, much can be achieved -- see in particular
3445 @ref{Graphic notation inside markup}.
3447 The following example demonstrates this by changing the note head
3448 symbol to a cross within a circle.
3450 @lilypond[verbatim,quote]
3452 \once \override NoteHead #'stencil = #ly:text-interface::print
3453 \once \override NoteHead #'text = \markup {
3455 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3456 \musicglyph #"noteheads.s2cross"
3464 Any of the glyphs in the feta Font can be supplied to the
3465 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3467 @c TODO Add inserting eps files or ref to later
3469 @c TODO Add inserting Postscript or ref to later
3474 @ref{Graphic notation inside markup},
3475 @ref{Formatting text},
3476 @ref{Text markup commands},
3477 @ref{The Feta font}.
3480 @node Modifying shapes
3481 @subsection Modifying shapes
3484 * Modifying ties and slurs::
3487 @node Modifying ties and slurs
3488 @unnumberedsubsubsec Modifying ties and slurs
3490 @cindex slurs, modifying
3491 @cindex ties, modifying
3492 @cindex Bézier curves
3493 @cindex Bézier control points
3495 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3496 curves. If the shape of the tie or slur which is calculated
3497 automatically is not optimum, the shape may be modified manually by
3498 explicitly specifying the four control points required to define
3499 a third-order Bézier curve.
3501 Third-order or cubic Bézier curves are defined by four control
3502 points. The first and fourth control points are precisely the
3503 starting and ending points of the curve. The intermediate two
3504 control points define the shape. Animations showing how the curve
3505 is drawn can be found on the web, but the following description
3506 may be helpful. The curve starts from the first control point
3507 heading directly towards the second, gradually bending over to
3508 head towards the third and continuing to bend over to head towards
3509 the fourth, arriving there travelling directly from the third
3510 control point. The curve is entirely contained in the
3511 quadrilateral defined by the four control points.
3513 Here is an example of a case where the tie is not optimum, and
3514 where @code{\tieDown} would not help.
3516 @lilypond[verbatim,quote,relative=1]
3520 { r4 <g c,> <g c,> <g c,> }
3524 One way of improving this tie is to manually modify its control
3527 The coordinates of the Bézier control points are specified in units
3528 of staff-spaces. The X@tie{}coordinate is relative to the reference
3529 point of the note to which the tie or slur is attached, and the
3530 Y@tie{}coordinate is relative to the staff center line. The
3531 coordinates are entered as a list of four pairs of decimal numbers
3532 (reals). One approach is to estimate the coordinates of the two
3533 end points, and then guess the two intermediate points. The optimum
3534 values are then found by trial and error.
3536 It is useful to remember that a symmetric curve requires symmetric
3537 control points, and that Bézier curves have the useful property that
3538 transformations of the curve such as translation, rotation and
3539 scaling can be achieved by applying the same transformation to the
3540 curve's control points.
3542 For the example above the following override gives a satisfactory
3543 tie. Note the placement -- it has to be immediately before the note
3544 to which the start of the tie (or slur) is attached.
3546 @lilypond[verbatim,quote,relative=1]
3550 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3554 { r4 <g c,> <g c,> <g c,>4 }
3560 It is not possible to modify shapes of ties or slurs by changing
3561 the @code{control-points} property if there are more than one at
3562 the same musical moment, not even by using the @code{\tweak}
3563 command. However, the @code{tie-configuration} property of
3564 @code{TieColumn} can be overridden to set start line and direction
3565 of ties as required.
3570 @node Using music functions
3571 @section Using music functions
3573 @c TODO -- add @seealso, etc. to these subsections
3575 Where tweaks need to be reused with different music expressions, it
3576 is often convenient to make the tweak part of a music function.
3577 In this section, we discuss only @emph{substitution} functions, where
3578 the object is to substitute a variable into a piece of LilyPond
3579 input code. Other more complex functions are described in
3580 @rextend{Music functions}.
3583 * Substitution function syntax::
3584 * Common argument types::
3585 * Substitution function examples::
3588 @node Substitution function syntax
3589 @subsection Substitution function syntax
3591 Making a function that substitutes a variable into LilyPond
3592 code is easy. The general form of these functions is
3596 #(define-music-function (parser location @var{var1} @var{var2}...@var{vari}... )
3597 (@var{var1-type?} @var{var2-type?}...@var{vari-type?}...)
3606 @multitable @columnfractions .33 .66
3607 @item @var{vari} @tab @var{i}th variable
3608 @item @var{vari-type?} @tab type of @var{i}th variable
3609 @item @var{...music...} @tab normal LilyPond input, using
3610 variables as @code{#$var1}, etc.
3613 Common variable types are described in @ref{Common argument types}.
3614 A more complete description of variable types is found in
3615 @rextend{Music function syntax}.
3617 The @code{parser} and @code{location} arguments are mandatory,
3618 and are used in some advanced situations as described in
3619 @rextend{Music function syntax}. For substitution functions, just be sure
3625 @ref{Common argument types}.
3628 @rextend{Music function syntax}.
3630 @node Common argument types
3631 @subsection Common argument types
3633 In order to allow for error checking, the type of each argument
3634 that is passed to a music function must be defined. Some of the
3635 common types of variables are shown in the table below.
3637 The following input types may be used as variables in a music
3638 function. This list is not exhaustive;
3639 more information about possible variable types
3640 can be found in @rextend{Music function syntax}.
3642 @multitable @columnfractions .33 .66
3643 @headitem Input type @tab @var{vari-type?} notation
3644 @item Integer @tab @code{integer?}
3645 @item Float (decimal number) @tab @code{number?}
3646 @item Text string @tab @code{string?}
3647 @item Markup @tab @code{markup?}
3648 @item Music expression @tab @code{ly:music?}
3649 @item A Scheme pair @tab @code{pair?}
3655 @rextend {Music function syntax}.
3658 @file{lily/music-scheme.cc},
3662 @node Substitution function examples
3663 @subsection Substitution function examples
3665 This section introduces some substitution function examples. These
3666 are not intended to be exhaustive, but rather to demonstrate some
3667 of the possibilities of simple substitution functions.
3669 In the first example, a function is defined that simplifies
3670 setting the padding of a TextScript:
3672 @lilypond[quote,verbatim,ragged-right]
3673 padText = #(define-music-function (parser location padding) (number?)
3675 \once \override TextScript #'padding = #$padding
3679 c4^"piu mosso" b a b
3681 c4^"piu mosso" d e f
3683 c4^"piu mosso" fis a g
3687 In addition to numbers, we can use music expressions such
3688 as notes for arguments to music functions:
3690 @lilypond[quote,verbatim,ragged-right]
3691 custosNote = #(define-music-function (parser location note)
3694 \once \override Voice.NoteHead #'stencil =
3695 #ly:text-interface::print
3696 \once \override Voice.NoteHead #'text =
3697 \markup \musicglyph #"custodes.mensural.u0"
3698 \once \override Voice.Stem #'stencil = ##f
3702 { c' d' e' f' \custosNote g' }
3705 Substitution functions with multiple arguments can be defined:
3707 @lilypond[quote,verbatim,ragged-right]
3708 tempoPadded = #(define-music-function (parser location padding tempotext)
3711 \once \override Score.MetronomeMark #'padding = $padding
3712 \tempo \markup { \bold $tempotext }
3716 \tempo \markup { "Low tempo" }
3718 \tempoPadded #4.0 #"High tempo"