1 @c -*- coding: utf-8; mode: texinfo; -*-
4 Translation of GIT committish: FILL-IN-HEAD-COMMITTISH
6 When revising a translation, copy the HEAD committish of the
7 version that you are working on. See TRANSLATION for details.
12 @node Changing defaults
13 @chapter Changing defaults
15 The purpose of LilyPond's design is to provide the finest quality
16 output by default. Nevertheless, it may happen that you need to
17 change this default layout. The layout is controlled through a large
18 number of @q{knobs and switches} collectively called @q{properties}.
19 A tutorial introduction to accessing and modifying these properties
20 can be found in the Learning Manual, see @rlearning{Tweaking output}.
21 This should be read first. This chapter covers similar ground, but
22 in a style more appropriate to a reference manual.
24 @cindex Internals Reference
26 The definitive description of the controls available for tuning can
27 be found in a separate document: @rinternalsnamed{Top,the Internals
28 Reference}. That manual lists all the variables, functions and
29 options available in LilyPond. It is written as a HTML document,
31 @c leave the @uref as one long line.
32 @uref{http://@/lilypond@/.org/@/doc/@/stable/@/Documentation/@/user/@/lilypond@/-internals/,on@/-line},
33 and is also included with the LilyPond documentation package.
35 Internally, LilyPond uses Scheme (a LISP dialect) to provide
36 infrastructure. Overriding layout decisions in effect accesses the
37 program internals, which requires Scheme input. Scheme elements are
38 introduced in a @code{.ly} file with the hash mark
39 @code{#}.@footnote{@rextend{Scheme tutorial}, contains a short tutorial
40 on entering numbers, lists, strings, and symbols in Scheme.}
44 * Interpretation contexts::
45 * Explaining the Internals Reference::
46 * Modifying properties::
47 * Useful concepts and properties::
49 * Using music functions::
53 @node Interpretation contexts
54 @section Interpretation contexts
56 This section describes what contexts are, and how to modify them.
59 * Contexts explained::
61 * Keeping contexts alive::
62 * Modifying context plug-ins::
63 * Changing context default settings::
64 * Defining new contexts::
71 @rlearning{Contexts and engravers}.
74 @file{ly/@/engraver@/-init@/.ly},
75 @file{ly/@/performer@/-init@/.ly}.
78 @rlsr{Contexts and engravers}.
81 @rinternals{Contexts},
82 @rinternals{Engravers and Performers}.
85 @node Contexts explained
86 @subsection Contexts explained
89 @c TODO Rethink and rewrite
91 >> > > - list of contexts: my *danger unmaintainable*
92 >> > > alarm just went off. I'm
94 I knew it would... And leaving out some of them is perfectly fine
96 I do think that a list like this, with the main contexts and a
98 description of what they do (perhaps also with a note about what
100 behavior is associated with each of them, but this may be
102 should be there, and then we could simply list the remaining ones
104 further explanation and with links to the IR.
107 @c TODO Improve layout, order and consistency of wording -td
109 @c TODO Add introduction which explains contexts in generality -td
111 @c TODO Describe propagation of property values -td
113 Contexts are arranged hierarchically:
116 * Score - the master of all contexts::
117 * Top-level contexts - staff containers::
118 * Intermediate-level contexts - staves::
119 * Bottom-level contexts - voices::
122 @node Score - the master of all contexts
123 @unnumberedsubsubsec Score - the master of all contexts
125 This is the top level notation context. No other context can
126 contain a Score context. By default the Score context handles
127 the administration of time signatures and makes sure that items
128 such as clefs, time signatures, and key-signatures are aligned
131 A Score context is instantiated implicitly when a
132 @code{\score @{@dots{}@}} or @code{\layout @{@dots{}@}} block is
133 processed, or explicitly when a @code{\new Score} command is
136 @node Top-level contexts - staff containers
137 @unnumberedsubsubsec Top-level contexts - staff containers
139 @strong{@emph{StaffGroup}}
141 Groups staves while adding a bracket on the left side, grouping
142 the staves together. The bar lines of the contained staves are
143 connected vertically. @code{StaffGroup} only consists of a collection
144 of staves, with a bracket in front and spanning bar lines.
146 @strong{@emph{ChoirStaff}}
148 Identical to @code{StaffGroup} except that the bar lines of the
149 contained staves are not connected vertically.
151 @strong{@emph{GrandStaff}}
153 A group of staves, with a brace on the left side, grouping the
154 staves together. The bar lines of the contained staves are
155 connected vertically.
157 @strong{@emph{PianoStaff}}
159 Just like @code{GrandStaff}, but with support for instrument names
160 to the left of each system.
162 @node Intermediate-level contexts - staves
163 @unnumberedsubsubsec Intermediate-level contexts - staves
165 @strong{@emph{Staff}}
167 Handles clefs, bar lines, keys, accidentals. It can contain
168 @code{Voice} contexts.
170 @strong{@emph{RhythmicStaff}}
172 Like @code{Staff} but for printing rhythms. Pitches are ignored;
173 the notes are printed on one line.
175 @strong{@emph{TabStaff}}
177 Context for generating tablature. By default lays the music
178 expression out as a guitar tablature, printed on six lines.
180 @strong{@emph{DrumStaff}}
182 Handles typesetting for percussion. Can contain @code{DrumVoice}
184 @strong{@emph{VaticanaStaff}}
186 Same as @code{Staff}, except that it is designed for typesetting
187 a piece in gregorian style.
189 @strong{@emph{MensuralStaff}}
191 Same as @code{Staff}, except that it is designed for typesetting
192 a piece in mensural style.
194 @node Bottom-level contexts - voices
195 @unnumberedsubsubsec Bottom-level contexts - voices
197 Voice-level contexts initialise certain properties and start
198 appropriate engravers. Being bottom-level contexts, they cannot
199 contain other contexts.
201 @strong{@emph{Voice}}
203 Corresponds to a voice on a staff. This context handles the
204 conversion of dynamic signs, stems, beams, super- and sub-scripts,
205 slurs, ties, and rests. You have to instantiate this explicitly
206 if you require multiple voices on the same staff.
208 @strong{@emph{VaticanaVoice}}
210 Same as @code{Voice}, except that it is designed for typesetting
211 a piece in gregorian style.
213 @strong{@emph{MensuralVoice}}
215 Same as @code{Voice}, with modifications for typesetting a piece in
218 @strong{@emph{Lyrics}}
220 Corresponds to a voice with lyrics. Handles the printing of a
221 single line of lyrics.
223 @strong{@emph{DrumVoice}}
225 The voice context used in a percussion staff.
227 @strong{@emph{FiguredBass}}
229 The context in which @code{BassFigure} objects are created from
230 input entered in @code{\figuremode} mode.
232 @strong{@emph{TabVoice}}
234 The voice context used within a @code{TabStaff} context. Usually
235 left to be created implicitly.
237 @strong{@emph{CueVoice}}
239 A voice context used to render notes of a reduced size, intended
240 primarily for adding cue notes to a staff, see @ref{Formatting
241 cue notes}. Usually left to be created implicitly.
243 @strong{@emph{ChordNames}}
245 Typesets chord names.
250 Then the following, which I don't know what to do with:
252 * GregorianTranscriptionVoice
253 * GregorianTranscriptionStaff
256 Engraves fretboards from chords. Not easy... Not
258 There is now some documentation on FretBoards in the NR, under
259 instrument-specific notation -- cds.
264 Hard coded entry point for LilyPond. Cannot be tuned.
266 Silently discards all musical information given to this
271 @node Creating contexts
272 @subsection Creating contexts
274 @c TODO \new Score and \score
275 @c TODO more complete descriptions rather than learning style
277 For scores with only one voice and one staff, contexts are
278 created automatically. For more complex scores, it is necessary to
279 create them by hand. There are three commands that do this.
284 The easiest command is @code{\new}, and it also the quickest to type.
285 It is prepended to a music expression, for example
289 @cindex Context, creating
292 \new @var{type} @var{music expression}
296 where @var{type} is a context name (like @code{Staff} or
297 @code{Voice}). This command creates a new context, and starts
298 interpreting the @var{music expression} with that.
300 A practical application of @code{\new} is a score with many
301 staves. Each part that should be on its own staff, is preceded with
304 @lilypond[quote,verbatim,relative=2,ragged-right,fragment]
311 The @code{\new} command may also give a name to the context,
314 \new @var{type} = @var{id} @var{music}
316 However, this user specified name is only used if there is no other
317 context already earlier with the same name.
323 Like @code{\new}, the @code{\context} command also directs a music
324 expression to a context object, but gives the context an explicit name. The
328 \context @var{type} = @var{id} @var{music}
331 This form will search for an existing context of type @var{type}
332 called @var{id}. If that context does not exist yet, a new
333 context with the specified name is created. This is useful if
334 the context is referred to later on. For example, when
335 setting lyrics the melody is in a named context
338 \context Voice = "@b{tenor}" @var{music}
342 so the texts can be properly aligned to its notes,
345 \new Lyrics \lyricsto "@b{tenor}" @var{lyrics}
350 Another possible use of named contexts is funneling two different
351 music expressions into one context. In the following example,
352 articulations and notes are entered separately,
356 arts = @{ s4-. s4-> @}
359 They are combined by sending both to the same @code{Voice} context,
363 \new Staff \context Voice = "A" \music
364 \context Voice = "A" \arts
367 @lilypond[quote,ragged-right]
371 \new Staff \context Voice = "A" \music
372 \context Voice = "A" \arts
376 With this mechanism, it is possible to define an Urtext (original
377 edition), with the option to put several distinct articulations on the
380 @cindex creating contexts
383 The third command for creating contexts is
385 \context @var{type} @var{music}
390 This is similar to @code{\context} with @code{= @var{id}}, but matches
391 any context of type @var{type}, regardless of its given name.
393 This variant is used with music expressions that can be interpreted at
394 several levels. For example, the @code{\applyOutput} command (see
395 @rextend{Running a function on all layout objects}). Without an explicit
396 @code{\context}, it is usually applied to @code{Voice}
399 \applyOutput #'@var{context} #@var{function} % apply to Voice
402 To have it interpreted at the @code{Score} or @code{Staff} level use
406 \applyOutput #'Score #@var{function}
407 \applyOutput #'Staff #@var{function}
412 @node Keeping contexts alive
413 @subsection Keeping contexts alive
415 @cindex contexts, keeping alive
416 @cindex contexts, lifetime
418 Contexts are usually terminated at the first musical moment in
419 which they have nothing to do. So @code{Voice} contexts die as
420 soon as they contain no events; @code{Staff} contexts die as soon
421 as all the @code{Voice} contexts within them contain no events; etc.
422 This can cause difficulties if earlier contexts which have died
423 have to be referenced, for example, when changing staves with
424 @code{\change} commands, associating lyrics with a voice with
425 @code{\lyricsto} commands, or when adding further musical events to
428 There is an exception to this general rule: just one of the
429 @code{Voice} contexts in a @code{Staff} context or in a
430 @code{<<...>>} construct will always persist to the end of the
431 enclosing @code{Staff} context or @code{<<...>>} construct, even
432 though there may be periods when it has nothing to do. The context
433 to persist in this way will be the first one encountered in the
434 first enclosed @code{@{...@}} construct, ignoring any in enclosed
435 @code{<<...>>} constructs.
437 Any context can be kept alive by ensuring it has something to do at
438 every musical moment. @code{Staff} contexts are kept alive by
439 ensuring one of their voices is kept alive. One way of doing this
440 is to add spacer rests to a voice in parallel with the real music.
441 These need to be added to every @code{Voice} context which needs to
442 be kept alive. If several voices are to be used sporadically it is
443 safest to keep them all alive rather than attempting to rely on the
444 exceptions mentioned above.
446 In the following example, both voice A and voice B are kept alive
447 in this way for the duration of the piece:
449 @lilypond[quote,verbatim]
450 musicA = \relative c'' { d4 d d d }
451 musicB = \relative c'' { g4 g g g }
454 \new Voice = "A" { s1*5 } % Keep Voice "A" alive for 5 bars
455 \new Voice = "B" { s1*5 } % Keep Voice "B" alive for 5 bars
460 \context Voice = "A" {
464 \context Voice = "B" {
468 \context Voice = "A" { \musicA }
469 \context Voice = "B" { \musicB }
470 \context Voice = "A" { \musicA }
481 @cindex lyrics, aligning with sporadic melody
483 The following example shows how a sporadic melody line with lyrics
484 might be written using this approach. In a real situation the
485 melody and accompaniment would consist of several different
488 @lilypond[quote,verbatim]
489 melody = \relative c'' { a4 a a a }
490 accompaniment = \relative c' { d4 d d d }
491 words = \lyricmode { These words fol -- low the mel -- o -- dy }
494 \new Staff = "music" {
496 \new Voice = "melody" {
498 s1*4 % Keep Voice "melody" alive for 4 bars
501 \new Voice = "accompaniment" {
506 \context Voice = "melody" { \melody }
507 \context Voice = "accompaniment" { \accompaniment }
509 \context Voice = "accompaniment" { \accompaniment }
511 \context Voice = "melody" { \melody }
512 \context Voice = "accompaniment" { \accompaniment }
517 \new Lyrics \with { alignAboveContext = #"music" }
518 \lyricsto "melody" { \words }
523 An alternative way, which may be better in many circumstances, is
524 to keep the melody line alive by simply including spacer notes to
525 line it up correctly with the accompaniment:
527 @lilypond[quote,verbatim]
528 melody = \relative c'' {
534 accompaniment = \relative c' {
540 words = \lyricmode { These words fol -- low the mel -- o -- dy }
544 \new Staff = "music" {
546 \new Voice = "melody" {
550 \new Voice = "accompaniment" {
556 \new Lyrics \with { alignAboveContext = #"music" }
557 \lyricsto "melody" { \words }
563 @node Modifying context plug-ins
564 @subsection Modifying context plug-ins
566 @c TODO Should this be Modifying engravers or Modifying contexts?
568 Notation contexts (like @code{Score} and @code{Staff}) not only
570 they also contain plug-ins called @q{engravers} that create notation
571 elements. For example, the @code{Voice} context contains a
572 @code{Note_head_engraver} and the @code{Staff} context contains a
573 @code{Key_signature_engraver}.
575 For a full a description of each plug-in, see
577 @rinternals{Engravers and Performers}.
580 Internals Reference @expansion{} Translation @expansion{} Engravers.
582 Every context described in
584 @rinternals{Contexts}
587 Internals Reference @expansion{} Translation @expansion{} Context.
589 lists the engravers used for that context.
592 It can be useful to shuffle around these plug-ins. This is done by
593 starting a new context with @code{\new} or @code{\context}, and
599 \new @var{context} \with @{
612 where the @dots{} should be the name of an engraver. Here is a simple
613 example which removes @code{Time_signature_engraver} and
614 @code{Clef_engraver} from a @code{Staff} context,
616 @lilypond[quote,relative=1,verbatim,fragment]
622 \remove "Time_signature_engraver"
623 \remove "Clef_engraver"
630 In the second staff there are no time signature or clef symbols. This
631 is a rather crude method of making objects disappear since it will affect
632 the entire staff. This method also influences the spacing, which may or
633 may not be desirable. More sophisticated methods of blanking objects
634 are shown in @rlearning{Visibility and color of objects}.
636 The next example shows a practical application. Bar lines and time
637 signatures are normally synchronized across the score. This is done
638 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
639 This plug-in keeps an administration of time signature, location
640 within the measure, etc. By moving these engraver from @code{Score} to
641 @code{Staff} context, we can have a score where each staff has its own
644 @cindex polymetric scores
645 @cindex Time signatures, multiple
647 @lilypond[quote,relative=1,ragged-right,verbatim,fragment]
649 \remove "Timing_translator"
650 \remove "Default_bar_line_engraver"
653 \consists "Timing_translator"
654 \consists "Default_bar_line_engraver"
660 \consists "Timing_translator"
661 \consists "Default_bar_line_engraver"
671 Usually the order in which the engravers are specified
672 does not matter, but in a few special cases the order
673 is important, for example where one engraver writes
674 a property and another reads it, or where one engraver
675 creates a grob and another must process it. The order in
676 which the engravers are specified is the order in which
677 they are called to carry out their processing.
679 The following orderings are important: the
680 @code{Bar_engraver} must normally be first, and
681 the @code{New_fingering_engraver} must come before
682 the @code{Script_column_engraver}. There may be others
683 with ordering dependencies.
685 @node Changing context default settings
686 @subsection Changing context default settings
688 The context settings which are to be used by default in
689 @code{Score}, @code{Staff} and @code{Voice} contexts may be specified
690 in a @code{\layout} block, as illustrated in the following example.
691 The @code{\layout} block should be placed within the @code{\score}
692 block to which it is to apply, but outside any music.
694 Note that the @code{\set} command itself and the context must be
695 omitted when the context default values are specified in this way:
697 @lilypond[quote,verbatim]
700 a4^"Really small, thicker stems, no time signature" a a a
707 \override Stem #'thickness = #4.0
708 \remove "Time_signature_engraver"
714 In this example, the @code{\Staff} command specifies that the
715 subsequent specifications are to be applied to all staves within
718 Modifications can be made to the @code{Score} context or all
719 @code{Voice} contexts in a similar way.
723 It is not possible to collect context changes in a variable and apply
724 them to a @code{\context} definition by referring to that variable.
726 The @code{\RemoveEmptyStaffContext} will overwrite your current
727 @code{\Staff} settings. If you wish to change the defaults for a
728 staff which uses @code{\RemoveEmptyStaffContext}, you must do so
729 after calling @code{\RemoveEmptyStaffContext}, ie
734 \RemoveEmptyStaffContext
736 \override Stem #'thickness = #4.0
741 @c TODO: add \with in here.
745 @node Defining new contexts
746 @subsection Defining new contexts
748 @cindex contexts, defining new
749 @cindex engravers, including in contexts
764 Specific contexts, like @code{Staff} and @code{Voice}, are made of
765 simple building blocks. It is possible to create new types of
766 contexts with different combinations of engraver plug-ins.
768 The next example shows how to build a different type of
769 @code{Voice} context from scratch. It will be similar to
770 @code{Voice}, but only prints centered slash note heads. It can be used
771 to indicate improvisation in jazz pieces,
773 @lilypond[quote,ragged-right]
776 \type "Engraver_group"
777 \consists "Note_heads_engraver"
778 \consists "Rhythmic_column_engraver"
779 \consists "Text_engraver"
780 \consists Pitch_squash_engraver
781 squashedPosition = #0
782 \override NoteHead #'style = #'slash
783 \override Stem #'transparent = ##t
787 \accepts "ImproVoice"
791 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
792 c4 c^"undress" c_"while playing :)" c }
798 These settings are defined within a @code{\context} block inside a
799 @code{\layout} block,
809 In the following discussion, the example input shown should go in place
810 of the @dots{} in the previous fragment.
812 First it is necessary to define a name for the new context:
818 Since it is similar to the @code{Voice}, we want commands that work
819 on (existing) @code{Voice}s to remain working. This is achieved by
820 giving the new context an alias @code{Voice},
826 The context will print notes and instructive texts, so we need to add
827 the engravers which provide this functionality,
830 \consists Note_heads_engraver
831 \consists Text_engraver
834 but we only need this on the center line,
837 \consists Pitch_squash_engraver
838 squashedPosition = #0
841 The @rinternals{Pitch_squash_engraver} modifies note heads (created
842 by @rinternals{Note_heads_engraver}) and sets their vertical
843 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
846 The notes look like a slash, and have no stem,
849 \override NoteHead #'style = #'slash
850 \override Stem #'transparent = ##t
853 All these plug-ins have to cooperate, and this is achieved with a
854 special plug-in, which must be marked with the keyword @code{\type}.
855 This should always be @code{Engraver_group}.
858 \type "Engraver_group"
866 \type "Engraver_group"
867 \consists "Note_heads_engraver"
868 \consists "Text_engraver"
869 \consists Pitch_squash_engraver
870 squashedPosition = #0
871 \override NoteHead #'style = #'slash
872 \override Stem #'transparent = ##t
878 Contexts form hierarchies. We want to hang the @code{ImproVoice}
879 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
880 modify the @code{Staff} definition with the @code{\accepts}
891 The opposite of @code{\accepts} is @code{\denies},
892 which is sometimes needed when reusing existing context definitions.
894 Putting both into a @code{\layout} block, like
904 \accepts "ImproVoice"
909 Then the output at the start of this subsection can be entered as
917 c c_"while playing :)"
924 @node Aligning contexts
925 @subsection Aligning contexts
927 New contexts may be aligned above or below existing contexts. This
928 could be useful in setting up a vocal staff (@rlearning{Vocal ensembles}) and
931 @c TODO Better example needed. Ref LM, and expand on it.
934 @funindex alignAboveContext
935 @funindex alignBelowContext
937 @lilypond[quote,ragged-right]
940 \relative c' \new Staff = "main" {
943 \new Staff \with { alignAboveContext = #"main" } \ossia
950 @cindex nested contexts
951 @cindex contexts, nested
956 Contexts like @code{PianoStaff} can contain other contexts
957 nested within them. Contexts which are acceptable for nesting
958 are defined by the @qq{accepts} list of a context. Contexts
959 which are not in this list are placed below the outer context
960 in the printed score.
961 For example, the @code{PianoStaff} context is defined by default
962 to accept @code{Staff} and @code{FiguredBass} contexts within
963 it, but not (for example) a @code{Lyrics} context. So in the
964 following structure the lyrics are placed below the piano staff
965 rather than between the two staves:
967 @lilypond[verbatim,quote,relative=1]
970 \new Staff { e4 d c2 }
971 \addlyrics { Three blind mice }
979 The @qq{accepts} list of a context can be modified to include
980 additional nested contexts, so if we wanted the lyrics to appear
981 between the two staves we could use:
983 @lilypond[verbatim,quote,relative=1]
984 \new PianoStaff \with { \accepts Lyrics }
986 \new Staff { e4 d c2 }
987 \addlyrics { Three blind mice }
995 The opposite of @code{\accepts} is @code{\denies}; this removes a
996 context from the @qq{accepts} list.
998 @node Explaining the Internals Reference
999 @section Explaining the Internals Reference
1003 * Navigating the program reference::
1004 * Layout interfaces::
1005 * Determining the grob property::
1006 * Naming conventions::
1009 @node Navigating the program reference
1010 @subsection Navigating the program reference
1012 @c TODO remove this (it's in the LM)
1013 @c Replace with more factual directions
1015 Suppose we want to move the fingering indication in the fragment
1018 @lilypond[quote,fragment,relative=2,verbatim]
1024 If you visit the documentation on fingering instructions (in
1025 @ref{Fingering instructions}), you will notice:
1030 Internals Reference: @rinternals{Fingering}.
1035 @c outdated info; probably will delete.
1037 This fragment points to two parts of the program reference: a page
1038 on @code{FingeringEvent} and one on @code{Fingering}.
1040 The page on @code{FingeringEvent} describes the properties of the music
1041 expression for the input @code{-2}. The page contains many links
1042 forward. For example, it says
1045 Accepted by: @rinternals{Fingering_engraver},
1049 That link brings us to the documentation for the Engraver, the
1053 This engraver creates the following layout objects: @rinternals{Fingering}.
1056 In other words, once the @code{FingeringEvent}s are interpreted, the
1057 @code{Fingering_engraver} plug-in will process them.
1061 @c I can't figure out what this is supposed to mean. -gp
1063 The @code{Fingering_engraver} is also listed to create
1064 @rinternals{Fingering} objects,
1066 @c old info? it doesn't make any sense to me with our current docs.
1068 second bit of information listed under @b{See also} in the Notation
1073 The programmer's reference is available as an HTML document. It is
1074 highly recommended that you read it in HTML form, either online or
1075 by downloading the HTML documentation. This section will be much more
1076 difficult to understand if you are using the
1080 Follow the link to @rinternals{Fingering}. At the top of the
1084 Fingering objects are created by: @rinternals{Fingering_engraver} and
1085 @rinternals{New_fingering_engraver}.
1088 By following related links inside the program reference, we can follow the
1089 flow of information within the program:
1093 @item @rinternals{Fingering}:
1094 @rinternals{Fingering} objects are created by:
1095 @rinternals{Fingering_engraver}
1097 @item @rinternals{Fingering_engraver}:
1098 Music types accepted: @rinternals{fingering-event}
1100 @item @rinternals{fingering-event}:
1101 Music event type @code{fingering-event} is in Music expressions named
1102 @rinternals{FingeringEvent}
1105 This path goes against the flow of information in the program: it
1106 starts from the output, and ends at the input event. You could
1107 also start at an input event, and read with the flow of
1108 information, eventually ending up at the output object(s).
1110 The program reference can also be browsed like a normal document. It
1111 contains chapters on
1113 @rinternals{Music definitions},
1116 @code{Music definitions}
1118 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1119 chapter lists all the definitions used and all properties that may be
1123 @node Layout interfaces
1124 @subsection Layout interfaces
1126 @cindex interface, layout
1127 @cindex layout interface
1130 The HTML page that we found in the previous section describes the
1131 layout object called @rinternals{Fingering}. Such an object is a
1132 symbol within the score. It has properties that store numbers (like
1133 thicknesses and directions), but also pointers to related objects. A
1134 layout object is also called a @emph{Grob}, which is short for Graphical
1135 Object. For more details about Grobs, see @rinternals{grob-interface}.
1137 The page for @code{Fingering} lists the definitions for the
1138 @code{Fingering} object. For example, the page says
1141 @code{padding} (dimension, in staff space):
1147 which means that the number will be kept at a distance of at least 0.5
1151 Each layout object may have several functions as a notational or
1152 typographical element. For example, the Fingering object
1153 has the following aspects
1157 Its size is independent of the horizontal spacing, unlike slurs or beams.
1160 It is a piece of text. Granted, it is usually a very short text.
1163 That piece of text is typeset with a font, unlike slurs or beams.
1166 Horizontally, the center of the symbol should be aligned to the
1167 center of the note head.
1170 Vertically, the symbol is placed next to the note and the staff.
1173 The vertical position is also coordinated with other superscript
1174 and subscript symbols.
1177 Each of these aspects is captured in so-called @emph{interface}s,
1178 which are listed on the @rinternals{Fingering} page at the bottom
1181 This object supports the following interfaces:
1182 @rinternals{item-interface},
1183 @rinternals{self-alignment-interface},
1184 @rinternals{side-position-interface}, @rinternals{text-interface},
1185 @rinternals{text-script-interface}, @rinternals{font-interface},
1186 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1189 Clicking any of the links will take you to the page of the respective
1190 object interface. Each interface has a number of properties. Some of
1191 them are not user-serviceable (@q{Internal properties}), but others
1194 We have been talking of @emph{the} @code{Fingering} object, but actually it
1195 does not amount to much. The initialization file (see
1196 @rlearning{Other sources of information})
1197 @file{scm/@/define@/-grobs@/.scm} shows the soul of the @q{object},
1202 (avoid-slur . around)
1203 (slur-padding . 0.2)
1204 (staff-padding . 0.5)
1205 (self-alignment-X . 0)
1206 (self-alignment-Y . 0)
1207 (script-priority . 100)
1208 (stencil . ,ly:text-interface::print)
1209 (direction . ,ly:script-interface::calc-direction)
1210 (font-encoding . fetaNumber)
1211 (font-size . -5) ; don't overlap when next to heads.
1212 (meta . ((class . Item)
1213 (interfaces . (finger-interface
1215 text-script-interface
1217 side-position-interface
1218 self-alignment-interface
1219 item-interface))))))
1223 As you can see, the @code{Fingering} object is nothing more than a
1224 bunch of variable settings, and the webpage in the Internals Reference
1225 is directly generated from this definition.
1228 @node Determining the grob property
1229 @subsection Determining the grob property
1231 @c TODO remove this (it's in the LM)
1232 @c Replace with more factual directions
1234 Recall that we wanted to change the position of the @b{2} in
1236 @lilypond[quote,fragment,relative=2,verbatim]
1242 Since the @b{2} is vertically positioned next to its note, we have to
1243 meddle with the interface associated with this positioning. This is
1244 done using @code{side-position-interface}. The page for this interface
1248 @code{side-position-interface}
1250 Position a victim object (this one) next to other objects (the
1251 support). The property @code{direction} signifies where to put the
1252 victim object relative to the support (left or right, up or down?)
1257 Below this description, the variable @code{padding} is described as
1262 (dimension, in staff space)
1264 Add this much extra space between objects that are next to each other.
1268 By increasing the value of @code{padding}, we can move the
1269 fingering away from the note head. The following command inserts
1270 3 staff spaces of white
1271 between the note and the fingering:
1273 \once \override Voice.Fingering #'padding = #3
1276 Inserting this command before the Fingering object is created,
1277 i.e., before @code{c2}, yields the following result:
1279 @lilypond[quote,relative=2,fragment,verbatim]
1280 \once \override Voice.Fingering #'padding = #3
1287 In this case, the context for this tweak is @code{Voice}. This
1288 fact can also be deduced from the program reference, for the page for
1289 the @rinternals{Fingering_engraver} plug-in says
1292 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1296 @node Naming conventions
1297 @subsection Naming conventions
1299 Another thing that is needed, is an overview of the various naming
1303 @item scheme functions: lowercase-with-hyphens (incl. one-word
1305 @item scheme functions: ly:plus-scheme-style
1306 @item music events, music classes and music properties:
1308 @item Grob interfaces: scheme-style
1309 @item backend properties: scheme-style (but X and Y!)
1310 @item contexts (and MusicExpressions and grobs): Capitalized or
1312 @item context properties: lowercaseFollowedByCamelCase
1314 Capitalized_followed_by_lowercase_and_with_underscores
1317 Questions to be answered:
1319 @item Which of these are conventions and which are rules?
1320 @item Which are rules of the underlying language, and which are
1324 @node Modifying properties
1325 @section Modifying properties
1327 @c TODO change the menu and subsection node names to use
1328 @c backslash once the new macro to handle the refs
1329 @c is available. Need to find and change all refs at
1330 @c the same time. -td
1333 * Overview of modifying properties::
1335 * The override command::
1336 * The tweak command::
1337 * set versus override::
1341 @node Overview of modifying properties
1342 @subsection Overview of modifying properties
1344 Each context is responsible for creating certain types of graphical
1345 objects. The settings used for printing these objects are also stored by
1346 context. By changing these settings, the appearance of objects can be
1349 There are two different kinds of properties stored in contexts:
1350 context properties and grob properties. Context properties are
1351 properties that apply to the context as a whole and control
1352 how the context itself is displayed. In contrast, grob properties
1353 apply to specific grob types that will be displayed in the context.
1355 The @code{\set} and @code{\unset} commands are used to change values
1356 for context properties. The @code{\override} and @code{\revert}
1357 commands are used to change values for grob properties.
1360 The syntax for this is
1363 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1366 Here @var{name} is the name of a graphical object, like
1367 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1368 variable of the formatting system (@q{grob property} or @q{layout
1369 property}). The latter is a symbol, so it must be quoted. The
1370 subsection @ref{Modifying properties}, explains what to fill in
1371 for @var{name}, @var{property}, and @var{value}. Here we only
1372 discuss the functionality of this command.
1377 \override Staff.Stem #'thickness = #4.0
1381 makes stems thicker (the default is 1.3, with staff line thickness as a
1382 unit). Since the command specifies @code{Staff} as context, it only
1383 applies to the current staff. Other staves will keep their normal
1384 appearance. Here we see the command in action:
1386 @lilypond[quote,verbatim,relative=2,fragment]
1388 \override Staff.Stem #'thickness = #4.0
1394 The @code{\override} command changes the definition of the @code{Stem}
1395 within the current @code{Staff}. After the command is interpreted
1396 all stems are thickened.
1398 Analogous to @code{\set}, the @var{context} argument may be left out,
1399 causing the default context @code{Voice} to be used. Adding
1400 @code{\once} applies the change during one timestep only.
1402 @lilypond[quote,fragment,verbatim,relative=2]
1404 \once \override Stem #'thickness = #4.0
1409 The @code{\override} must be done before the object is
1410 started. Therefore, when altering @emph{Spanner} objects such as slurs
1411 or beams, the @code{\override} command must be executed at the moment
1412 when the object is created. In this example,
1414 @lilypond[quote,fragment,verbatim,relative=2]
1415 \override Slur #'thickness = #3.0
1417 \override Beam #'thickness = #0.6
1422 the slur is fatter but the beam is not. This is because the command for
1423 @code{Beam} comes after the Beam is started, so it has no effect.
1425 Analogous to @code{\unset}, the @code{\revert} command for a context
1426 undoes an @code{\override} command; like with @code{\unset}, it only
1427 affects settings that were made in the same context. In other words, the
1428 @code{\revert} in the next example does not do anything.
1431 \override Voice.Stem #'thickness = #4.0
1432 \revert Staff.Stem #'thickness
1435 Some tweakable options are called @q{subproperties} and reside inside
1436 properties. To tweak those, use commands of the form
1438 @c leave this as a long long
1440 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1447 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1454 @rinternals{Backend},
1455 @rinternals{All layout objects},
1456 @rinternals{OverrideProperty},
1457 @rinternals{RevertProperty},
1458 @rinternals{PropertySet}.
1463 The back-end is not very strict in type-checking object properties.
1464 Cyclic references in Scheme values for properties can cause hangs
1465 or crashes, or both.
1469 @node The set command
1470 @subsection The @code{\set} command
1474 @cindex changing properties
1476 Each context has a set of @emph{properties}, variables contained
1477 in that context. Context properties are changed with the @code{\set}
1478 command, which has the following syntax:
1481 \set @var{context}.@var{property} = #@var{value}
1484 @var{value} is a Scheme object, which is why it must be preceded by
1485 the @code{#} character.
1487 Contexts properties are usually named in
1488 @code{studlyCaps}. They mostly control the translation from
1489 music to notation, e.g. @code{localKeySignature} (for determining
1490 whether to print accidentals), or @code{measurePosition} (for
1491 determining when to print a bar line). Context properties can
1492 change value over time while interpreting a piece of music;
1493 @code{measurePosition} is an obvious example of
1494 this. Context properties are modified with @code{\set}.
1496 For example, multimeasure rests will be combined into a single bar
1497 if the context property @code{skipBars} is set to @code{#t}:
1499 @lilypond[quote,verbatim,relative=2,fragment]
1501 \set Score.skipBars = ##t
1505 If the @var{context} argument is left out, then the property will be
1506 set in the current bottom context (typically @code{ChordNames},
1507 @code{Voice}, @code{TabVoice}, or @code{Lyrics}).
1509 @lilypond[quote,verbatim,relative=2,fragment]
1510 \set Score.autoBeaming = ##f
1514 \set autoBeaming = ##t
1522 The change is applied @q{on-the-fly}, during the music, so that the
1523 setting only affects the second group of eighth notes.
1525 Note that the bottom-most context does not always contain the property
1526 that you wish to change -- for example, attempting to set the
1527 @code{skipBars} property of the default bottom context, in this case
1528 @code{Voice}, will have no effect, because skipBars is a property of
1529 the @code{Score} context.
1531 @lilypond[quote,verbatim,relative=2,fragment]
1537 Contexts are hierarchical, so if an enclosing context was specified, for
1538 example @code{Staff}, then the change would also apply to all
1539 @code{Voice}s in the current staff.
1543 The @code{\unset} command:
1546 \unset @var{context}.@var{property}
1550 is used to remove the definition of @var{property} from
1551 @var{context}. This command removes
1552 the definition only if it is set in @var{context}.
1553 Properties that have been set in enclosing contexts will
1554 not be altered by an unset in an enclosed context:
1556 @lilypond[quote,verbatim,relative=2,fragment]
1557 \set Score.autoBeaming = ##t
1562 \unset Score.autoBeaming
1570 Like @code{\set}, the @var{context} argument does not have to be
1571 specified for a bottom context, so the two statements
1574 \set Voice.autoBeaming = ##t
1575 \set autoBeaming = ##t
1579 are equivalent if the current bottom context is @code{Voice}.
1583 Preceding a @code{\set} command by @code{\once} makes the
1584 setting apply to only a single time-step:
1586 @lilypond[quote,verbatim,relative=2,fragment]
1588 \once \set fontSize = #4.7
1593 A full description of all available context properties is in the
1594 internals reference, see
1596 @rinternals{Tunable context properties}.
1599 Translation @expansion{} Tunable context properties.
1604 Internals Reference:
1606 @rinternals{Tunable context properties}.
1609 @cindex grob properties
1610 @cindex properties, grob
1614 @node The override command
1615 @subsection The @code{\override} command
1617 There is a special type of context property: the grob
1618 description. Grob descriptions are named in @code{StudlyCaps}
1619 (starting with capital letters). They contain the
1620 @q{default settings} for a particular kind of grob as an
1621 association list. See @file{scm/@/define@/-grobs@/.scm}
1622 to see the settings for each grob description. Grob descriptions
1623 are modified with @code{\override}.
1625 @code{\override} is actually a shorthand;
1628 \override @var{context}.@var{GrobName} #'@var{property} = #@var{value}
1632 is more or less equivalent to
1634 @c leave this long line -gp
1636 \set @var{context}.@var{GrobName} =
1637 #(cons (cons '@var{property} @var{value})
1638 <previous value of @var{context}.@var{GrobName}>)
1641 The value of @code{context}.@code{GrobName} (the alist) is used to initialize
1642 the properties of individual grobs. Grobs have
1643 properties, named in Scheme style, with
1644 @code{dashed-words}. The values of grob properties change
1645 during the formatting process: formatting basically amounts
1646 to computing properties using callback functions.
1648 For example, we can increase the thickness of a note stem by
1649 overriding the @code{thickness} property of the @code{Stem}
1652 @lilypond[quote, verbatim, relative=2, fragment]
1654 \override Voice.Stem #'thickness = #3.0
1658 If no context is specified in an @code{\override}, the bottom
1661 @lilypond[quote, verbatim, relative=2, fragment]
1662 { \override Staff.Stem #'thickness = #3.0
1666 \override Stem #'thickness = #0.5
1676 @cindex reverting overrides
1677 @cindex overrides, reverting
1679 The effects of @code{\override} can be undone by @code{\revert}:
1681 @lilypond[quote, verbatim, relative=2, fragment]
1683 \override Voice.Stem #'thickness = #3.0
1685 \revert Voice.Stem #'thickness
1689 The effects of @code{\override} and @code{\revert} apply to all
1690 grobs in the affected context from the current time forward:
1692 @lilypond[quote, verbatim, relative=2, fragment]
1697 \override Staff.Stem #'thickness = #3.0
1701 \revert Staff.Stem #'thickness
1709 @cindex overriding for only one moment
1711 @code{\once} can be used with @code{\override}
1712 to affect only the current time step:
1714 @lilypond[quote, verbatim, relative=2, fragment]
1718 \override Stem #'thickness = #3.0
1722 \once \override Stem #'thickness = #3.0
1731 Commands which change output generally look like
1734 \override Voice.Stem #'thickness = #3.0
1738 To construct this tweak we must determine these bits of information:
1741 @item the context: here @code{Voice}.
1742 @item the layout object: here @code{Stem}.
1743 @item the layout property: here @code{thickness}.
1744 @item a sensible value: here @code{3.0}.
1747 Some tweakable options are called @q{subproperties} and reside inside
1748 properties. To tweak those, use commands in the form
1751 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1754 @cindex internal documentation
1755 @cindex finding graphical objects
1756 @cindex graphical object descriptions
1759 @cindex internal documentation
1761 For many properties, regardless of the data type of the property, setting the
1762 property to false ( @code{##f} ) will result in turning it off, causing
1763 LilyPond to ignore that property entirely. This is particularly useful for
1764 turning off grob properties which may otherwise be causing problems.
1766 We demonstrate how to glean this information from the notation manual
1767 and the program reference.
1772 Internals Reference:
1773 @rinternals{Backend}
1775 @node The tweak command
1776 @subsection The @code{\tweak} command
1781 Changing grob properties
1782 with @code{\override} causes the changes to apply to all of the
1783 given grobs in the context at the moment the change applies.
1784 Sometimes, however, it is desirable to have changes apply to just
1785 one grob, rather than to all grobs in the affected context. This is
1786 accomplished with the @code{\tweak} command, which has the following
1790 \tweak #'@code{grob-property} #@code{value}
1793 The @code{\tweak} command applies to the object that immediately
1794 follows @code{value} in the music stream.
1797 In some cases, it is possible to take a short-cut for tuning
1798 graphical objects. For objects that are created directly from
1799 an item in the input file, you can use the @code{\tweak} command.
1802 @lilypond[relative=2,verbatim,quote]
1807 \tweak #'duration-log #1
1810 -\tweak #'padding #8
1816 But the main use of the @code{\tweak} command is to modify just
1817 one of a number of notation elements which start at the same musical
1818 moment, like the notes of a chord, or tuplet brackets which start
1821 The @code{\tweak} command sets a property in the following object
1822 directly, without requiring the grob name or context to be
1823 specified. For this to work, it is necessary for the @code{\tweak}
1824 command to remain immediately adjacent to the object to which it is
1825 to apply after the input file has been converted to a music stream.
1826 This is often not the case, as many additional elements are inserted
1827 into the music stream implicitly. For example, when a note which is
1828 not part of a chord is processed, LilyPond implicitly inserts a
1829 @code{ChordEvent} event before the note, so separating the tweak
1830 from the note. However, if chord symbols are placed round the
1831 tweak and the note, the @code{\tweak} command comes after the
1832 @code{ChordEvent} in the music stream, so remaining adjacent to the
1833 note, and able to modify it.
1837 @lilypond[relative=2,verbatim,quote]
1838 <\tweak #'color #red c>4
1844 @lilypond[relative=2,verbatim,quote]
1845 \tweak #'color #red c4
1850 For an introduction to the syntax and uses of the tweak command
1851 see @rlearning{Tweaking methods}.
1853 When several similar items are placed at the same musical moment,
1854 the @code{\override} command cannot be used to modify just one of
1855 them -- this is where the @code{\tweak} command must be used.
1856 Items which may appear more than once at the same musical moment
1857 include the following:
1859 @c TODO expand to include any further uses of \tweak
1861 @item note heads of notes inside a chord
1862 @item articulation signs on a single note
1863 @item ties between notes in a chord
1864 @item tuplet brackets starting at the same time
1867 @c TODO add examples of these
1869 @cindex chord, modifying one note in
1871 In this example, the color of one note head and the type of another
1872 note head are modified within a single chord:
1874 @lilypond[relative=2,verbatim,quote]
1879 \tweak #'duration-log #1
1884 @code{\tweak} can be used to modify slurs:
1886 @lilypond[verbatim,quote,relative=1]
1887 c-\tweak #'thickness #5 ( d e f)
1891 For the @code{\tweak} command to work, it must
1892 remain immediately adjacent to the object to which it is
1893 to apply after the input file has been converted to a music stream.
1894 At times, LilyPond may insert additional items into the music stream
1895 during the parsing process. For example, when a note that is not
1896 explicitly part of a chord will be placed in a chord by LilyPond,
1897 so notes to be modified with @code{\tweak} must be placed inside
1900 @lilypond[relative=2,verbatim,quote]
1901 \tweak #'color #red c4
1902 <\tweak #'color #red c>4
1905 The @code{\tweak} command cannot be used to modify any item
1906 that does not appear explicitly in the input file. In particular
1907 it cannot be used to modify stems,
1908 beams or accidentals directly, since these are generated later by
1909 note heads, rather than by music elements in the input stream.
1910 Nor can @code{\tweak} be used to modify clefs or time
1911 signatures, since these become separated from any preceding
1912 @code{\tweak} command in the input stream by the automatic
1913 insertion of extra elements required to specify the context.
1915 Several @code{\tweak} commands may be placed before a
1916 notational element -- all affect it:
1918 @lilypond[verbatim,quote,relative=1]
1920 -\tweak #'style #'dashed-line
1921 -\tweak #'dash-fraction #0.2
1922 -\tweak #'thickness #3
1923 -\tweak #'color #red
1928 The music stream which is generated from a section of an input file,
1929 including any automatically inserted elements, may be examined,
1930 see @rextend{Displaying music expressions}. This may be helpful in
1931 determining what may be modified by a @code{\tweak} command, or
1932 in determining how to adjust the input to make a @code{\tweak}
1938 @rlearning{Tweaking methods}.
1941 @rextend{Displaying music expressions}.
1946 @cindex tweaks in a variable
1947 The @code{\tweak} command cannot be used inside a variable.
1949 @cindex tweaks in lyrics
1950 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1952 @cindex tweaking control points
1953 @cindex control points, tweaking
1955 The @code{\tweak} command will apply to only the first of several
1956 generated ties in a chord.
1958 @node set versus override
1959 @subsection @code{\set} vs. @code{\override}
1961 TODO -- This section is probably unnecessary now.
1964 We have seen two methods of changing properties: @code{\set} and
1965 @code{\override}. There are actually two different kinds of
1968 @code{fontSize} is a special property: it is equivalent to
1969 entering @code{\override ... #'font-size} for all pertinent
1970 objects. Since this is a common change, the special
1971 property (modified with @code{\set}) was created.
1975 @node Useful concepts and properties
1976 @section Useful concepts and properties
1981 * Direction and placement::
1982 * Context layout order::
1983 * Distances and measurements::
1984 * Staff symbol properties::
1986 * Visibility of objects::
1988 * Rotating objects::
1992 @subsection Input modes
1994 The way in which the notation contained within an input file is
1995 interpreted is determined by the current input mode.
1999 This is activated with the @code{\chordmode} command, and causes
2000 input to be interpreted with the syntax of chord notation, see
2001 @ref{Chord notation}. Chords are rendered as notes on a staff.
2003 Chord mode is also activated with the @code{\chords} command.
2004 This also creates a new @code{ChordNames} context and
2005 causes the following input to be interpreted with the syntax of
2006 chord notation and rendered as chord names in the @code{ChordNames}
2007 context, see @ref{Printing chord names}.
2011 This is activated with the @code{\drummode} command, and causes
2012 input to be interpreted with the syntax of drum notation, see
2013 @ref{Basic percussion notation}.
2015 Drum mode is also activated with the @code{\drums} command.
2016 This also creates a new @code{DrumStaff} context and causes the
2017 following input to be interpreted with the syntax of drum notation
2018 and rendered as drum symbols on a drum staff, see @ref{Basic
2019 percussion notation}.
2021 @strong{Figure mode}
2023 This is activated with the @code{\figuremode} command, and causes
2024 input to be interpreted with the syntax of figured bass, see
2025 @ref{Entering figured bass}.
2027 Figure mode is also activated with the @code{\figures} command.
2028 This also creates a new @code{FiguredBass} context and causes the
2029 following input to be interpreted with the figured bass syntax
2030 and rendered as figured bass symbols in the @code{FiguredBass}
2031 context, see @ref{Introduction to figured bass}.
2033 @strong{Fret and tab modes}
2035 There are no special input modes for entering fret and tab symbols.
2037 To create tab diagrams, enter notes or chords in note mode and
2038 render them in a @code{TabStaff} context, see
2039 @ref{Default tablatures}.
2041 To create fret diagrams above a staff, you have two choices.
2042 You can either use the @code{FretBoards} context (see
2043 @ref{Automatic fret diagrams} or you can enter them as a markup
2044 above the notes using the @code{\fret-diagram} command (see
2045 @ref{Fret diagram markups}).
2047 @strong{Lyrics mode}
2049 This is activated with the @code{\lyricmode} command, and causes
2050 input to be interpreted as lyric syllables with optional durations
2051 and associated lyric modifiers, see @ref{Vocal music}.
2053 Lyric mode is also activated with the @code{\addlyrics} command.
2054 This also creates a new @code{Lyrics} context and an implicit
2055 @code{\lyricsto} command which associates the following lyrics
2056 with the preceding music.
2058 @strong{Markup mode}
2060 This is activated with the @code{\markup} command, and causes
2061 input to be interpreted with the syntax of markup, see
2062 @ref{Text markup commands}.
2064 @c silly work-around for texinfo broken-ness
2065 @c (@strong{Note...} causes a spurious cross-reference in Info)
2068 This is the default mode or it may be activated with the
2069 @code{\notemode} command. Input is interpreted as pitches,
2070 durations, markup, etc and typeset as musical notation on a staff.
2072 It is not normally necessary to specify note mode explicitly, but
2073 it may be useful to do so in certain situations, for example if you
2074 are in lyric mode, chord mode or any other mode and want to insert
2075 something that only can be done with note mode syntax.
2077 For example, to indicate dynamic markings for the verses of a
2078 choral pieces it is necessary to enter note mode to interpret
2081 @lilypond[verbatim,relative=2,quote]
2084 \notemode{\set stanza = \markup{ \dynamic f 1. } }
2088 \notemode{\set stanza = \markup{ \dynamic p 2. } }
2095 @node Direction and placement
2096 @subsection Direction and placement
2098 In typesetting music the direction and placement of many items is
2099 a matter of choice. For example, the stems of notes can
2100 be directed up or down; lyrics, dynamics, and other expressive
2101 marks may be placed above or below the staff; text may be aligned
2102 left, right or center; etc. Most of these choices may be left to
2103 be determined automatically by LilyPond, but in some cases it may
2104 be desirable to force a particular direction or placement.
2106 @strong{Articulation direction indicators}
2108 By default some directions are always up or always down (e.g.
2109 dynamics or fermata), while other things can alternate between
2110 up or down based on the stem direction (like slurs or accents).
2112 @c TODO Add table showing these
2114 The default action may be overridden by prefixing the articulation
2115 by a @emph{direction indicator}. Three direction indicators are
2116 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
2117 and @code{-} (meaning @qq{use default direction}). The direction
2118 indicator can usually be omitted, in which case @code{-} is assumed,
2119 but a direction indicator is @strong{always} required before
2122 @item @code{\tweak} commands
2123 @item @code{\markup} commands
2124 @item @code{\tag} commands
2125 @item string markups, e.g. -"string"
2126 @item fingering instructions, e.g. @code{-1}
2127 @item articulation shortcuts, e.g. @code{-.}, @code{->}, @code{--}
2130 Direction indicators affect only the next note:
2132 @lilypond[verbatim,quote,relative=2]
2139 @strong{The direction property}
2141 The position or direction of many layout objects is controlled
2142 by the @code{direction} property.
2144 The value of the @code{direction} property may be
2145 set to @code{1}, meaning @qq{up} or @qq{above}, or to @code{-1},
2146 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
2147 @code{DOWN} may be used instead of @code{1} and @code{-1}
2148 respectively. The default direction may be specified by setting
2149 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
2150 in many cases predefined commands
2151 exist to specify the direction. These are all of the form
2154 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
2157 where @code{xxxNeutral} means @qq{use the default direction}.
2158 See @rlearning{Within-staff objects}.
2160 In a few cases, arpeggio being the only common example, the value
2161 of the @code{direction} property specifies whether the object
2162 is to be placed to the right or left of the parent object. In
2163 this case @code{-1} or @code{LEFT} means @qq{to the left} and
2164 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
2165 or @code{CENTER} means @qq{use the default} direction, as before.
2168 These all have side-axis set to #X
2169 AmbitusAccidental - direction has no effect
2171 StanzaNumber - not tried
2172 TrillPitchAccidental - not tried
2173 TrillPitchGroup - not tried
2176 These indications affect all notes until they are cancelled.
2178 @lilypond[verbatim,quote,relative=2]
2188 @node Context layout order
2189 @subsection Context layout order
2191 @cindex contexts, layout order
2193 Contexts are normally positioned in a system from top to bottom
2194 in the order in which they are encountered in the input file. When
2195 contexts are nested, the outer context will include inner nested
2196 contexts as specified in the input file, provided the inner contexts
2197 are included in the outer context's @qq{accepts} list. Nested
2198 contexts which are not included in the outer context's @qq{accepts}
2199 list will be repositioned below the outer context rather than nested
2202 Note that a context will be silently created implicitly if a command
2203 is encountered when there is no suitable context available to
2204 contain it. This can give rise to unexpected new staves or scores.
2206 The default order in which contexts are laid out and the
2207 @qq{accepts} list can be changed, see @ref{Aligning contexts}.
2211 @rprogram{An extra staff appears}.
2214 @node Distances and measurements
2215 @subsection Distances and measurements
2217 @cindex distances, absolute
2218 @cindex distances, scaled
2225 Distances in LilyPond are of two types: absolute and scaled.
2227 Absolute distances are used for specifying margins, indents, and
2228 other page layout details, and are by default specified in
2229 millimeters. Distances may be specified in other units by
2230 following the quantity by @code{\mm}, @code{\cm},
2231 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27
2232 of an inch). Page layout distances can also be specified in
2233 scalable units (see the following paragraph) by appending
2234 @code{\staff-space} to the quantity.
2235 Page layout is described in detail in @ref{Page formatting}.
2237 Scaled distances are always specified in units of the staff-space
2238 or, rarely, the half staff-space. The staff-space is the distance
2239 between two adjacent staff lines. The default value can be changed
2240 globally by setting the global staff size, or it can be overridden
2241 locally by changing the @code{staff-space} property of
2242 @code{StaffSymbol}. Scaled distances automatically scale with any
2243 change to the either the global staff size or the
2244 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2245 automatically only with changes to the global staff size.
2246 The global staff size thus enables the overall size of a rendered
2247 score to be easily varied. For the methods of setting the global
2248 staff size see @ref{Setting the staff size}.
2252 If just a section of a score needs to be rendered to a different
2253 scale, for example an ossia section or a footnote, the global staff
2254 size cannot simply be changed as this would affect the entire score.
2255 In such cases the change in size is made by overriding both the
2256 @code{staff-space} property of @code{StaffSymbol} and the size of
2257 the fonts. A Scheme function, @code{magstep}, is available to
2258 convert from a font size change to the equivalent change in
2259 @code{staff-space}. For an explanation and an example of its use,
2260 see @rlearning{Length and thickness of objects}.
2265 @rlearning{Length and thickness of objects}.
2268 @ref{Page formatting},
2269 @ref{Setting the staff size}.
2272 @node Staff symbol properties
2273 @subsection Staff symbol properties
2275 @cindex adjusting staff symbol
2276 @cindex drawing staff symbol
2277 @cindex staff symbol, setting of
2279 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2280 @c Need to think of uses for these properties. Eg 'line-positions
2281 @c is used in a snippet to thicken centre line.
2282 @c If retained, add @ref to here in 1.6.2 -td
2284 The vertical position of staff lines and the number of staff lines
2285 can be defined at the same time. As the following example shows,
2286 note positions are not influenced by the staff line positions.
2288 @warning{The @code{'line-positions} property overrides the
2289 @code{'line-count} property. The number of staff lines is
2290 implicitly defined by the number of elements in the list of values
2291 for @code{'line-positions}.}
2293 @lilypond[verbatim,quote,relative=1]
2295 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
2300 The width of a staff can be modified. The units are staff
2301 spaces. The spacing of objects inside the staff is not affected by
2304 @lilypond[verbatim,quote,relative=1]
2306 \override StaffSymbol #'width = #23
2313 @subsection Spanners
2315 Many objects of musical notation extend over several notes or even
2316 several bars. Examples are slurs, beams, tuplet brackets, volta
2317 repeat brackets, crescendi, trills, and glissandi. Such objects
2318 are collectively called @qq{spanners}, and have special properties to control
2319 their appearance and behaviour. Some of these properties are common
2320 to all spanners; others are restricted to a sub-set of the spanners.
2322 All spanners support the @code{spanner-interface}. A few, esentially
2323 those that draw a straight line between the two objects, support in
2324 addition the @code{line-spanner-interface}.
2326 @unnumberedsubsubsec Using the @code{spanner-interface}
2328 This interface provides two properties that apply to several spanners.
2330 @strong{@i{The @code{minimum-length} property}}
2332 The minimum length of the spanner is specified by the
2333 @code{minimum-length} property. Increasing this usually has the
2334 necessary effect of increasing the spacing of the notes between the
2335 two end points. However, this override has no effect on
2336 many spanners, as their length is determined by other considerations.
2337 A few examples where it is effective are shown below.
2347 Works as long as callback is made:
2351 Works not at all for:
2360 @lilypond[verbatim,quote,relative=2]
2363 % increase the length of the tie
2364 -\tweak #'minimum-length #5
2368 @lilypond[verbatim,quote,relative=2]
2370 \compressFullBarRests
2372 % increase the length of the rest bar
2373 \once \override MultiMeasureRest #'minimum-length = #20
2378 @lilypond[verbatim,quote,relative=2]
2380 % increase the length of the hairpin
2381 \override Hairpin #'minimum-length = #20
2385 This override can also be used to increase the length of slurs and
2388 @lilypond[verbatim,quote,relative=2]
2391 -\tweak #'minimum-length #5
2396 -\tweak #'minimum-length #5
2400 For some layout objects, the @code{minimum-length} property becomes
2401 effective only if the @code{set-spacing-rods} procedure is called
2402 explicitly. To do this, the @code{springs-and-rods} property should
2403 be set to @code{ly:spanner::set-spacing-rods}. For example,
2404 the minimum length of a glissando has no effect unless the
2405 @code{springs-and-rods} property is set:
2407 @lilypond[verbatim,quote,relative=1]
2411 % not effective alone
2412 \once \override Glissando #'minimum-length = #20
2415 % effective only when both overrides are present
2416 \once \override Glissando #'minimum-length = #20
2417 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2421 The same is true of the @code{Beam} object:
2423 @lilypond[verbatim,quote,relative=1]
2424 % not effective alone
2425 \once \override Beam #'minimum-length = #20
2428 % effective only when both overrides are present
2429 \once \override Beam #'minimum-length = #20
2430 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2434 @strong{@i{The @code{to-barline} property}}
2436 The second useful property of the @code{spanner-interface} is
2437 @code{to-barline}. By default this is true, causing hairpins and
2438 other spanners which are terminated on the first note of a measure to
2439 end instead on the immediately preceding bar line. If set to false,
2440 the spanner will extend beyond the bar line and end on the note
2443 @lilypond[verbatim,quote,relative=2]
2444 a \< a a a a \! a a a \break
2445 \override Hairpin #'to-barline = ##f
2446 a \< a a a a \! a a a
2449 This property is not effective for all spanners. For example,
2450 seting it to @code{#t} has no effect on slurs or phrasing slurs
2451 or on other spanners for which terminating on the bar line would
2454 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2456 Objects which support the @code{line-spanner-interface} include
2459 @item @code{DynamicTextSpanner}
2460 @item @code{Glissando}
2461 @item @code{TextSpanner}
2462 @item @code{TrillSpanner}
2463 @item @code{VoiceFollower}
2466 The routine responsible for drawing the stencils for these spanners is
2467 @code{ly:line-interface::print}. This routine determines the
2468 exact location of the two end points and draws a line
2469 between them, in the style requested. The locations of the two
2470 end points of the spanner are computed on-the-fly, but it is
2471 possible to override their Y-coordinates. The
2472 properties which need to be specified are nested
2473 two levels down within the property hierarchy, but the syntax of
2474 the @code{\override} command is quite simple:
2476 @lilypond[relative=2,quote,verbatim]
2478 \once \override Glissando #'(bound-details left Y) = #3
2479 \once \override Glissando #'(bound-details right Y) = #-2
2483 The units for the @code{Y} property are @code{staff-space}s,
2484 with the center line of the staff being the zero point.
2485 For the glissando, this is the value for @code{Y} at the
2486 X-coordinate corresponding to the center point of each note head,
2487 if the line is imagined to be extended to there.
2489 If @code{Y} is not set, the value is computed from the vertical
2490 position of the corresponding attachment point of the spanner.
2492 In case of a line break, the values for the end points are
2493 specified by the @code{left-broken} and @code{right-broken}
2494 sub-lists of @code{bound-details}. For example:
2496 @lilypond[relative=2,ragged-right,verbatim,fragment]
2497 \override Glissando #'breakable = ##t
2498 \override Glissando #'(bound-details right-broken Y) = #-3
2499 c1 \glissando \break
2504 A number of further properties of the @code{left} and
2505 @code{right} sub-lists of the @code{bound-details} property
2506 may be modified in the same way as @code{Y}:
2510 This sets the Y-coordinate of the end point, in @code{staff-space}s
2511 offset from the staff center line. By default, it is the center of
2512 the bound object, so a glissando points to the vertical center of
2515 For horizontal spanners, such as text spanners and trill spanners,
2516 it is hardcoded to 0.
2519 This determines where the line starts and ends in the X-direction,
2520 relative to the bound object. So, a value of @code{-1} (or
2521 @code{LEFT}) makes the line start/end at the left side of the note
2522 head it is attached to.
2525 This is the absolute X-coordinate of the end point. It is usually
2526 computed on the fly, and overriding it has little useful effect.
2529 Line spanners may have symbols at the beginning or end, which is
2530 contained in this sub-property. This is for internal use; it is
2531 recommended that @code{text} be used instead.
2534 This is a markup that is evaluated to yield the stencil. It is used
2535 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2537 @lilypond[quote,ragged-right,fragment,relative=2,verbatim]
2538 \override TextSpanner #'(bound-details left text)
2539 = \markup { \small \bold Slower }
2540 c2\startTextSpan b c a\stopTextSpan
2543 @item stencil-align-dir-y
2544 @item stencil-offset
2545 Without setting one of these, the stencil is simply put at the
2546 end-point, centered on the line, as defined by the @code{X} and
2547 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2548 or @code{stencil-offset} will move the symbol at the edge vertically
2549 relative to the end point of the line:
2551 @lilypond[relative=1,fragment,verbatim]
2552 \override TextSpanner
2553 #'(bound-details left stencil-align-dir-y) = #-2
2554 \override TextSpanner
2555 #'(bound-details right stencil-align-dir-y) = #UP
2557 \override TextSpanner
2558 #'(bound-details left text) = #"ggg"
2559 \override TextSpanner
2560 #'(bound-details right text) = #"hhh"
2561 c4^\startTextSpan c c c \stopTextSpan
2564 Note that negative values move the text @emph{up}, contrary to the
2565 effect that might be expected, as a value of @code{-1} or
2566 @code{DOWN} means align the @emph{bottom} edge of the text with
2567 the spanner line. A value of @code{1} or @code{UP} aligns
2568 the top edge of the text with the spanner line.
2571 Setting this sub-property to @code{#t} produces an arrowhead at the
2575 This sub-property controls the space between the specified
2576 end point of the line and the actual end. Without padding, a
2577 glissando would start and end in the center of each note head.
2581 The music function @code{\endSpanners} terminates the spanner
2582 which starts on the immediately following note prematurely. It
2583 is terminated after exactly one note, or at the following bar line
2584 if @code{to-barline} is true and a bar line occurs before the next
2587 @lilypond[verbatim,quote,ragged-right,relative=2,fragment]
2589 c2 \startTextSpan c2 c2
2594 When using @code{\endSpanners} it is not necessary to close
2595 \startTextSpan with \stopTextSpan, nor is it necessary to close
2596 hairpins with @code{\!}.
2600 Internals Reference:
2601 @rinternals{TextSpanner},
2602 @rinternals{Glissando},
2603 @rinternals{VoiceFollower},
2604 @rinternals{TrillSpanner},
2605 @rinternals{line-spanner-interface}.
2608 @node Visibility of objects
2609 @subsection Visibility of objects
2611 @cindex objects, visibility of
2612 @cindex grobs, visibility of
2613 @cindex visibility of objects
2615 There are four main ways in which the visibility of layout objects
2616 can be controlled: their stencil can be removed, they can be made
2617 transparent, they can be colored white, or their
2618 @code{break-visibility} property can be overridden. The first
2619 three apply to all layout objects; the last to just a few -- the
2620 @emph{breakable} objects. The Learning Manual introduces these
2621 four techniques, see @rlearning{Visibility and color of objects}.
2623 There are also a few other techniques which are specific to
2624 certain layout objects. These are covered under Special
2628 * Removing the stencil::
2629 * Making objects transparent::
2630 * Painting objects white::
2631 * Using break-visibility::
2632 * Special considerations::
2636 @node Removing the stencil
2637 @unnumberedsubsubsec Removing the stencil
2639 @cindex stencil, removing
2641 Every layout object has a stencil property. By default this is set
2642 to the specific function which draws that object. If this property
2643 is overridden to @code{#f} no function will be called and the object
2644 will not be drawn. The default action can be recovered with
2647 @lilypond[quote,verbatim,relative=1]
2649 \override Score.BarLine #'stencil = ##f
2651 \revert Score.BarLine #'stencil
2655 @node Making objects transparent
2656 @unnumberedsubsubsec Making objects transparent
2658 @cindex transparent, making objects
2660 Every layout object has a transparent property which by default is
2661 set to @code{#f}. If set to @code{#t} the object still occupies
2662 space but is made invisible.
2664 @lilypond[quote,verbatim,relative=2]
2666 \once \override NoteHead #'transparent = ##t
2670 @node Painting objects white
2671 @unnumberedsubsubsec Painting objects white
2673 @cindex objects, coloring
2674 @cindex coloring objects
2676 @cindex printing order
2677 @cindex overwriting objects
2678 @cindex objects, overwriting
2679 @cindex grobs, overwriting
2681 Every layout object has a color property which by default is set
2682 to @code{black}. If this is overridden to @code{white} the object
2683 will be indistinguishable from the white background. However,
2684 if the object crosses other objects the color of the crossing
2685 points will be determined by the order in which they are drawn,
2686 and this may leave a ghostly image of the white object, as shown
2689 @lilypond[quote,verbatim,relative=2]
2690 \override Staff.Clef #'color = #white
2694 This may be avoided by changing the order of printing the objects.
2695 All layout objects have a @code{layer} property which should be set
2696 to an integer. Objects with the lowest value of @code{layer} are
2697 drawn first, then objects with progressively higher values are drawn,
2698 so objects with higher values overwrite objects with lower values.
2699 By default most objects are assigned a @code{layer} value of
2700 @code{1}, although a few objects, including @code{StaffSymbol} and
2701 @code{BarLine}, are assigned a value of @code{0}. The order of
2702 printing objects with the same value of @code{layer} is indeterminate.
2704 In the example above the white clef, with a default @code{layer}
2705 value of @code{1}, is drawn after the staff lines (default
2706 @code{layer} value @code{0}), so overwriting them. To change this,
2707 the @code{Clef} object must be given in a lower value of
2708 @code{layer}, say @code{-1}, so that it is drawn earlier:
2710 @lilypond[quote,verbatim,relative=2]
2711 \override Staff.Clef #'color = #white
2712 \override Staff.Clef #'layer = #-1
2716 @node Using break-visibility
2717 @unnumberedsubsubsec Using break-visibility
2719 @c TODO Add making other objects breakable
2721 @cindex break-visibility
2723 Most layout objects are printed only once, but some like
2724 bar lines, clefs, time signatures and key signatures, may need
2725 to be printed twice when a line break occurs -- once at the end
2726 of the line and again at the start of the next line. Such
2727 objects are called @emph{breakable}, and have a property, the
2728 @code{break-visibility} property to control their visibility
2729 at the three positions in which they may appear -- at the
2730 start of a line, within a line if they are changed, and at the
2731 end of a line if a change takes place there.
2733 For example, the time signature
2734 by default will be printed at the start of the first line, but
2735 nowhere else unless it changes, when it will be printed at the
2736 point at which the change occurs. If this change occurs at the
2737 end of a line the new time signature will be printed at the start
2738 of the next line and a cautionary time signature will be printed
2739 at the end of the previous line as well.
2741 This behaviour is controlled by the @code{break-visibility}
2742 property, which is explained in
2743 @c Leave this ref on a newline - formats incorrectly otherwise -td
2744 @rlearning{Visibility and color of objects}. This property takes
2745 a vector of three booleans which, in order, determine whether the
2746 object is printed at the end of, within the body of, or at the
2747 beginning of a line. Or to be more precise, before a line break,
2748 where there is no line break, or after a line break.
2750 Alternatively, these eight combinations may be specified
2751 by pre-defined functions, defined in @file{scm/@/output@/-lib@/.scm},
2752 where the last three columns indicate whether the layout objects
2753 will be visible in the positions shown at the head of the columns:
2755 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2756 @headitem Function @tab Vector @tab Before @tab At no @tab After
2757 @headitem form @tab form @tab break @tab break @tab break
2759 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2760 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2761 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2762 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2763 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2764 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2765 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2766 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2769 The default settings of @code{break-visibility} depend on the
2770 layout object. The following table shows all the layout objects
2771 of interest which are affected by @code{break-visibility} and the
2772 default setting of this property:
2774 @multitable @columnfractions .3 .3 .4
2776 @headitem Layout object @tab Usual context @tab Default setting
2778 @c omit Ambitus as it appears not to be affected by break-visibility -td
2779 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2780 @item @code{BarLine} @tab @code{Score} @tab calculated
2781 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2782 @c omit the following item until it can be explained -td
2783 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2784 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2785 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2786 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2787 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2788 @c omit KeyCancellation until it can be explained -td
2789 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2790 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2791 @c omit LeftEdge until it can be explained -td
2792 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2793 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2794 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2795 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2799 The example below shows the use of the vector form to control the
2800 visibility of barlines:
2802 @lilypond[quote,verbatim,relative=1,ragged-right]
2805 % Remove bar line at the end of the current line
2806 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2812 Although all three components of the vector used to override
2813 @code{break-visibility} must be present, not all of them are
2814 effective with every layout object, and some combinations may
2815 even give errors. The following limitations apply:
2818 @item Bar lines cannot be printed at start of line.
2819 @item A bar number cannot be printed at the start of the first
2820 line unless it is set to be different from 1.
2821 @item Clef -- see below
2822 @item Double percent repeats are either all printed or all
2823 suppressed. Use begin-of line-invisible to print and
2824 all-invisible to suppress.
2825 @item Key signature -- see below
2826 @item OctavateEight -- see below
2829 @node Special considerations
2830 @unnumberedsubsubsec Special considerations
2832 @strong{@emph{Visibility following explicit changes}}
2834 @cindex key signature, visibility following explicit change
2835 @cindex explicitKeySignatureVisibility
2836 @cindex clef, visibility following explicit change
2837 @cindex explicitClefVisibility
2839 The @code{break-visibility} property controls the visibility of
2840 key signatures and changes of clef only at the start of lines,
2841 i.e. after a break. It has no effect on the visibility of the
2842 key signature or clef following an explicit key change or an
2843 explicit clef change within or at the end of a line. In the
2844 following example the key signature following the explicit change
2845 to B-flat major is still visible, even though @code{all-invisible}
2848 @lilypond[quote,verbatim,relative=1,ragged-right]
2851 % Try to remove all key signatures
2852 \override Staff.KeySignature #'break-visibility = #all-invisible
2860 The visibility of such explicit key signature and clef changes is
2861 controlled by the @code{explicitKeySignatureVisibility} and
2862 @code{explicitClefVisibility} properties. These are the equivalent
2863 of the @code{break-visibility} property and both take a vector of
2864 three booleans or the predefined functions listed above, exactly like
2865 @code{break-visibility}. Both are properties of the Staff context,
2866 not the layout objects themselves, and so they are set using the
2867 @code{\set} command. Both are set by default to @code{all-visible}.
2868 These properties control only the visibility of key signatures and
2869 clefs resulting from explicit changes and do not affect key
2870 signatures and clefs at the beginning of lines;
2871 @code{break-visibility} must still be overridden in the appropriate
2872 object to remove these.
2874 @lilypond[quote,verbatim,relative=1,ragged-right]
2877 \set Staff.explicitKeySignatureVisibility = #all-invisible
2878 \override Staff.KeySignature #'break-visibility = #all-invisible
2885 @strong{@emph{Visibility of cautionary accidentals}}
2887 To remove the cautionary accidentals printed at an explicit key
2888 change, set the Staff context property @code{printKeyCancellation}
2891 @lilypond[quote,verbatim,relative=1,ragged-right]
2894 \set Staff.explicitKeySignatureVisibility = #all-invisible
2895 \set Staff.printKeyCancellation = ##f
2896 \override Staff.KeySignature #'break-visibility = #all-invisible
2903 With these overrides only the accidentals before the notes remain
2904 to indicate the change of key.
2906 @c TODO Add visibility of cautionary accidentals before notes
2908 @strong{@emph{Automatic bars}}
2910 @cindex automaticBars
2911 @cindex bar lines, suppressing
2913 As a special case, the printing of bar lines can also be turned off
2914 by setting the @code{automaticBars} property in the Score context.
2915 If set to @code{#f}, bar lines will not be printed automatically;
2916 they must be explicitly created with a @code{\bar} command. Unlike
2917 the @code{\cadenzaOn} predefined command, measures are still counted.
2918 Bar generation will resume according to that count if this property
2919 is later set to @code{#t}. When set to @code{#f}, line breaks can
2920 occur only at explicit @code{\bar} commands.
2924 @strong{@emph{Octavated clefs}}
2926 @cindex octavated clefs, visibility of
2927 @cindex visibility of octavated clefs
2928 @cindex clefs, visibility of octavation
2930 The small octavation symbol on octavated clefs is produced by the
2931 @code{OctavateEight} layout object. Its visibility is controlled
2932 independently from that of the @code{Clef} object, so it is
2933 necessary to apply any required @code{break-visibility} overrides
2934 to both the @code{Clef} and the @code{OctavateEight} layout objects
2935 to fully suppress such clef symbols at the start of each line.
2937 For explicit clef changes, the @code{explicitClefVisibility}
2938 property controls both the clef symbol and any octavation symbol
2944 @rlearning{Visibility and color of objects}
2948 @subsection Line styles
2950 Some performance indications, e.g., @i{rallentando} and
2951 @i{accelerando} and @i{trills} are written as text and are
2952 extended over many measures with lines, sometimes dotted or wavy.
2954 These all use the same routines as the glissando for drawing the
2955 texts and the lines, and tuning their behavior is therefore also
2956 done in the same way. It is done with a spanner, and the routine
2957 responsible for drawing the spanners is
2958 @code{ly:line-interface::print}. This routine determines the
2959 exact location of the two @i{span points} and draws a line
2960 between them, in the style requested.
2962 Here is an example showing the different line styles available,
2963 and how to tune them.
2965 @lilypond[relative=2,ragged-right,verbatim,fragment]
2967 \once \override Glissando #'style = #'dashed-line
2969 \override Glissando #'style = #'dotted-line
2971 \override Glissando #'style = #'zigzag
2973 \override Glissando #'style = #'trill
2977 The locations of the end-points of the spanner are computed
2978 on-the-fly for every graphic object, but it is possible to
2982 @lilypond[relative=2,ragged-right,verbatim,fragment]
2984 \once \override Glissando #'(bound-details right Y) = #-2
2988 The value for @code{Y} is set to @code{-2} for the right end
2989 point. The left side may be similarly adjusted by specifying
2990 @code{left} instead of @code{right}.
2992 If @code{Y} is not set, the value is computed from the vertical
2993 position of the left and right attachment points of the spanner.
2995 Other adjustments of spanners are possible, for details, see
2998 @node Rotating objects
2999 @subsection Rotating objects
3001 Both layout objects and elements of markup text can be rotated by
3002 any angle about any point, but the method of doing so differs.
3005 * Rotating layout objects::
3009 @node Rotating layout objects
3010 @unnumberedsubsubsec Rotating layout objects
3012 @cindex rotating objects
3013 @cindex objects, rotating
3015 All layout objects which support the @code{grob-interface} can be
3016 rotated by setting their @code{rotation} property. This takes a
3017 list of three items: the angle of rotation counter-clockwise,
3018 and the x and y coordinates of the point relative to the object's
3019 reference point about which the rotation is to be performed. The
3020 angle of rotation is specified in degrees and the coordinates in
3023 The angle of rotation and the coordinates of the rotation point must
3024 be determined by trial and error.
3026 @cindex hairpins, angled
3027 @cindex angled hairpins
3029 There are only a few situations where the rotation of layout
3030 objects is useful; the following example shows one situation where
3033 @lilypond[quote,verbatim,relative=1]
3035 \override Hairpin #'rotation = #'(20 -1 0)
3039 @node Rotating markup
3040 @unnumberedsubsubsec Rotating markup
3042 All markup text can be rotated to lie at any angle by prefixing it
3043 with the @code{\rotate} command. The command takes two arguments:
3044 the angle of rotation in degrees counter-clockwise and the text to
3045 be rotated. The extents of the text are not rotated: they take
3046 their values from the extremes of the x and y coordinates of the
3047 rotated text. In the following example the
3048 @code{outside-staff-priority} property for text is set to @code{#f}
3049 to disable the automatic collision avoidance, which would push some
3050 of the text too high.
3052 @lilypond[quote,verbatim,relative=1]
3053 \override TextScript #'outside-staff-priority = ##f
3054 g4^\markup { \rotate #30 "a G" }
3055 b^\markup { \rotate #30 "a B" }
3056 des^\markup { \rotate #30 "a D-Flat" }
3057 fis^\markup { \rotate #30 "an F-Sharp" }
3060 @node Advanced tweaks
3061 @section Advanced tweaks
3063 This section discusses various approaches to fine tuning the
3064 appearance of the printed score.
3067 * Aligning objects::
3068 * Vertical grouping of grobs::
3069 * Modifying stencils::
3070 * Modifying shapes::
3076 @rlearning{Tweaking output},
3077 @rlearning{Other sources of information}.
3080 @ref{Explaining the Internals Reference},
3081 @ref{Modifying properties},
3084 @file{scm/@/define@/-grobs@/.scm}.
3087 @rlsr{Tweaks and overrides}.
3090 @rextend{Interfaces for programmers}.
3092 Internals Reference:
3093 @rinternals{All layout objects}.
3096 @node Aligning objects
3097 @subsection Aligning objects
3099 Graphical objects which support the @code{self-alignment-interface} and/or
3100 the @code{side-position-interface} can be
3101 aligned to a previously placed object in a variety of ways. For a list of these objects, see
3102 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
3104 All graphical objects have a reference point, a horizontal extent and a
3105 vertical extent. The horizontal extent is a pair of numbers
3106 giving the displacements from the reference point of the left and
3107 right edges, displacements to the left being negative. The
3108 vertical extent is a pair of numbers giving the displacement from
3109 the reference point to the bottom and top edges, displacements down
3112 An object's position on a staff is given by the values of the
3113 @code{X-offset} and @code{Y-offset} properties. The value of
3114 @code{X-offset} gives the displacement from the x coordinate of
3115 the reference point of the parent object, and the value of
3116 @code{Y-offset} gives the displacement from the center line of the
3117 staff. The values of @code{X-offset} and
3118 @code{Y-offset} may be set directly or may be set to be calculated
3119 by procedures in order to achieve alignment with the parent object
3122 @warning{Many objects have special positioning considerations which
3123 cause any setting of @code{X-offset} or @code{Y-offset} to be
3124 ignored or modified, even though the object supports the
3125 @code{self-alignment-interface}.}
3127 For example, an accidental can be repositioned
3128 vertically by setting @code{Y-offset} but any changes to
3129 @code{X-offset} have no effect.
3131 Rehearsal marks may be aligned with
3132 breakable objects such as bar lines, clef symbols, time signature
3133 symbols and key signatures. There are special properties to be
3134 found in the @code{break-aligned-interface} for positioning rehearsal
3135 marks on such objects.
3138 * Setting @code{X-offset} and @code{Y-offset} directly::
3139 * Using the @code{side-position-interface}::
3140 * Using the @code{self-alignment-interface}::
3141 * Using the @code{break-alignable-interface}::
3144 @node Setting @code{X-offset} and @code{Y-offset} directly
3145 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
3147 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
3148 properties of many objects. The following example shows three
3149 notes with the default fingering position and the positions with @code{X-offset}
3150 and @code{Y-offset} modified.
3152 @lilypond[verbatim,quote,relative=2]
3155 -\tweak #'X-offset #0
3156 -\tweak #'Y-offset #0
3159 -\tweak #'X-offset #-1
3160 -\tweak #'Y-offset #1
3166 @node Using the @code{side-position-interface}
3167 @unnumberedsubsubsec Using the @code{side-position-interface}
3169 An object which supports the @code{side-position-interface} can be
3170 placed next to its parent object so that
3171 the specified edges of the two objects touch. The object may be
3172 placed above, below, to the right or to the left of the parent.
3173 The parent cannot be specified; it is determined by the order of
3174 elements in the input stream. Most objects have the associated
3175 note head as their parent.
3177 The values of the @code{side-axis} and @code{direction} properties
3178 determine where the object is to be placed, as follows:
3180 @c TODO add an example of each to the table
3182 @multitable @columnfractions .3 .3 .3
3183 @headitem @code{side-axis} @tab @code{direction} @tab
3184 @headitem property @tab property @tab Placement
3186 @item @code{0} @tab @code{-1} @tab left
3187 @item @code{0} @tab @code{1} @tab right
3188 @item @code{1} @tab @code{-1} @tab below
3189 @item @code{1} @tab @code{1} @tab above
3193 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
3194 the procedure @code{ly:side-position-interface::x-aligned-side}.
3195 This procedure will return the correct value of @code{X-offset} to
3196 place the object to the left or right side of the parent according
3197 to value of @code{direction}.
3199 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3200 the procedure @code{ly:side-position-interface::y-aligned-side}.
3201 This procedure will return the correct value of @code{Y-offset} to
3202 place the object to the top or bottom of the parent according
3203 to value of @code{direction}.
3205 @c TODO Add examples
3207 @node Using the @code{self-alignment-interface}
3208 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3210 @emph{Self-aligning objects horizontally}
3212 The horizontal alignment of an object which supports the
3213 @code{self-alignment-interface} is controlled by the value of
3214 the @code{self-alignment-X} property, provided the object's
3215 @code{X-offset} property is set to
3216 @code{ly:self-alignment-interface::x-aligned-on-self}.
3217 @code{self-alignment-X} may be given any
3218 real value, in units of half the total X extent of the
3219 object. Negative values move the object to the right, positive
3220 to the left. A value of @code{0} centers the object on the
3221 reference point of its parent, a value of @code{-1} aligns the
3222 left edge of the object on the reference point of its parent,
3223 and a value of @code{1} aligns the right edge of the object on the
3224 reference point of its parent. The symbols @code{LEFT},
3225 @code{CENTER} and @code{RIGHT} may be used instead of the values
3226 @code{-1, 0, 1} respectively.
3228 Normally the @code{\override} command would be used to modify the
3229 value of @code{self-alignment-X}, but the @code{\tweak} command
3230 can be used to separately align several annotations on a single
3233 @lilypond[quote,verbatim,relative=1]
3235 -\tweak #'self-alignment-X #-1
3237 -\tweak #'self-alignment-X #0
3239 -\tweak #'self-alignment-X #RIGHT
3241 -\tweak #'self-alignment-X #-2.5
3242 ^"aligned further to the right"
3245 @emph{Self-aligning objects vertically}
3247 Objects may be aligned vertically in an analogous way to aligning
3248 them horizontally if the @code{Y-offset} property is set to
3249 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3250 other mechanisms are often involved in vertical alignment: the
3251 value of @code{Y-offset} is just one variable taken into account.
3252 This may make adjusting the value of some objects tricky.
3253 The units are just half the vertical extent of the object, which
3254 is usually quite small, so quite large numbers may be required.
3255 A value of @code{-1} aligns the lower edge of the object with
3256 the reference point of the parent object, a value of @code{0}
3257 aligns the center of the object with the reference point of the
3258 parent, and a value of @code{1} aligns the top edge of the object
3259 with the reference point of the parent. The symbols @code{DOWN},
3260 @code{CENTER}, @code{UP} may be substituted for @code{-1, 0, 1}
3263 @emph{Self-aligning objects in both directions}
3265 By setting both @code{X-offset} and @code{Y-offset}, an object may
3266 be aligned in both directions simultaneously.
3268 The following example shows how to adjust a fingering mark so
3269 that it nestles close to the note head.
3271 @lilypond[quote,verbatim,relative=2]
3273 -\tweak #'self-alignment-X #0.5 % move horizontally left
3274 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
3275 -\tweak #'self-alignment-Y #-1 % move vertically up
3280 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3282 @c Cannot document as they do not seem to operate consistently on all objects -td
3283 @c TODO investigate further
3285 The @code{aligned-on-parent} procedures are used in the same way
3286 as the @code{aligned-on-self} procedures, they difference being
3287 that they permit an object to be aligned with the @emph{edges} of
3288 the parent rather than the parent's reference point. The following
3289 example shows the difference:
3293 @lilypond[verbatim,quote]
3299 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3301 @c Cannot document as they do not seem to operate consistently on all objects -td
3302 @c TODO investigate further
3306 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3308 @node Using the @code{break-alignable-interface}
3309 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3311 @cindex align to objects
3312 @cindex break-align-symbols
3314 Rehearsal marks and bar numbers may be aligned with notation
3315 objects other than bar lines. These objects include @code{ambitus},
3316 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3317 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3318 @code{time-signature}.
3320 By default, rehearsal marks and bar numbers will be horizontally
3321 centered above the object:
3323 @lilypond[verbatim,quote,relative=1]
3325 % the RehearsalMark will be centered above the Clef
3326 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
3331 % the RehearsalMark will be centered above the TimeSignature
3332 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
3340 A list of possible target alignment objects may be specified. If
3341 some of the objects are invisible at that point due to the setting
3342 of @code{break-visibility} or the explicit visibility settings for
3343 keys and clefs, the rehearsal mark or bar number is aligned to the
3344 first object in the list which is visible. If no objects in the
3345 list are visible the object is aligned to the bar line. If the bar
3346 line is invisible the object is aligned to the place where the bar
3349 @lilypond[verbatim,quote,relative=1]
3351 % the RehearsalMark will be centered above the Key Signature
3352 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3357 % the RehearsalMark will be centered above the Clef
3358 \set Staff.explicitKeySignatureVisibility = #all-invisible
3359 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3366 The alignment of the rehearsal mark relative to the notation object
3367 can be changed, as shown in the following example. In a score with
3368 multiple staves, this setting should be done for all the staves.
3370 @lilypond[verbatim,quote,relative=1]
3371 % The RehearsalMark will be centered above the KeySignature
3372 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3378 % The RehearsalMark will be aligned with the left edge of the KeySignature
3379 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3383 % The RehearsalMark will be aligned with the right edge of the KeySignature
3384 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3390 The rehearsal mark can also be offset to the right or left of the left edge
3391 by an arbitrary amount. The units are staff-spaces:
3393 @lilypond[verbatim,quote,relative=1]
3394 % The RehearsalMark will be aligned with the left edge of the KeySignature
3395 % and then shifted right by 3.5 staff-spaces
3396 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3397 \once \override Score.KeySignature #'break-align-anchor = #3.5
3401 % The RehearsalMark will be aligned with the left edge of the KeySignature
3402 % and then shifted left by 2 staff-spaces
3403 \once \override Score.KeySignature #'break-align-anchor = #-2
3410 @node Vertical grouping of grobs
3411 @subsection Vertical grouping of grobs
3413 @c FIXME Expand this section
3415 The VerticalAlignment and VerticalAxisGroup grobs work together.
3416 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3417 etc. VerticalAlignment then vertically aligns the different grobs
3418 grouped together by VerticalAxisGroup. There is usually only one
3419 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3423 @node Modifying stencils
3424 @subsection Modifying stencils
3426 All layout objects have a @code{stencil} property which is part of
3427 the @code{grob-interface}. By default, this property is usually
3428 set to a function specific to the object that is tailor-made to
3429 render the symbol which represents it in the output. For example,
3430 the standard setting for the @code{stencil} property of the
3431 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3433 The standard symbol for any object can be replaced by modifying the
3434 @code{stencil} property to reference a different, specially-written,
3435 procedure. This requires a high level of knowledge of the internal
3436 workings of LilyPond, but there is an easier way which can often
3437 produce adequate results.
3439 This is to set the @code{stencil} property to the procedure which
3440 prints text -- @code{ly:text-interface::print} -- and to add a
3441 @code{text} property to the object which is set to contain the
3442 markup text which produces the required symbol. Due to the
3443 flexibility of markup, much can be achieved -- see in particular
3444 @ref{Graphic notation inside markup}.
3446 The following example demonstrates this by changing the note head
3447 symbol to a cross within a circle.
3449 @lilypond[verbatim,quote]
3451 \once \override NoteHead #'stencil = #ly:text-interface::print
3452 \once \override NoteHead #'text = \markup {
3454 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3455 \musicglyph #"noteheads.s2cross"
3463 Any of the glyphs in the feta Font can be supplied to the
3464 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3466 @c TODO Add inserting eps files or ref to later
3468 @c TODO Add inserting Postscript or ref to later
3473 @ref{Graphic notation inside markup},
3474 @ref{Formatting text},
3475 @ref{Text markup commands},
3476 @ref{The Feta font}.
3479 @node Modifying shapes
3480 @subsection Modifying shapes
3483 * Modifying ties and slurs::
3486 @node Modifying ties and slurs
3487 @unnumberedsubsubsec Modifying ties and slurs
3489 @cindex slurs, modifying
3490 @cindex ties, modifying
3491 @cindex Bézier curves
3492 @cindex Bézier control points
3494 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3495 curves. If the shape of the tie or slur which is calculated
3496 automatically is not optimum, the shape may be modified manually by
3497 explicitly specifying the four control points required to define
3498 a third-order Bézier curve.
3500 Third-order or cubic Bézier curves are defined by four control
3501 points. The first and fourth control points are precisely the
3502 starting and ending points of the curve. The intermediate two
3503 control points define the shape. Animations showing how the curve
3504 is drawn can be found on the web, but the following description
3505 may be helpful. The curve starts from the first control point
3506 heading directly towards the second, gradually bending over to
3507 head towards the third and continuing to bend over to head towards
3508 the fourth, arriving there travelling directly from the third
3509 control point. The curve is entirely contained in the
3510 quadrilateral defined by the four control points.
3512 Here is an example of a case where the tie is not optimum, and
3513 where @code{\tieDown} would not help.
3515 @lilypond[verbatim,quote,relative=1]
3519 { r4 <g c,> <g c,> <g c,> }
3523 One way of improving this tie is to manually modify its control
3526 The coordinates of the Bézier control points are specified in units
3527 of staff-spaces. The X@tie{}coordinate is relative to the reference
3528 point of the note to which the tie or slur is attached, and the
3529 Y@tie{}coordinate is relative to the staff center line. The
3530 coordinates are entered as a list of four pairs of decimal numbers
3531 (reals). One approach is to estimate the coordinates of the two
3532 end points, and then guess the two intermediate points. The optimum
3533 values are then found by trial and error.
3535 It is useful to remember that a symmetric curve requires symmetric
3536 control points, and that Bézier curves have the useful property that
3537 transformations of the curve such as translation, rotation and
3538 scaling can be achieved by applying the same transformation to the
3539 curve's control points.
3541 For the example above the following override gives a satisfactory
3542 tie. Note the placement -- it has to be immediately before the note
3543 to which the start of the tie (or slur) is attached.
3545 @lilypond[verbatim,quote,relative=1]
3549 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3553 { r4 <g c,> <g c,> <g c,>4 }
3559 It is not possible to modify shapes of ties or slurs by changing
3560 the @code{control-points} property if there are more than one at
3561 the same musical moment, not even by using the @code{\tweak}
3562 command. However, the @code{tie-configuration} property of
3563 @code{TieColumn} can be overridden to set start line and direction
3564 of ties as required.
3569 @node Using music functions
3570 @section Using music functions
3572 @c TODO -- add @seealso, etc. to these subsections
3574 Where tweaks need to be reused with different music expressions, it
3575 is often convenient to make the tweak part of a music function.
3576 In this section, we discuss only @emph{substitution} functions, where
3577 the object is to substitute a variable into a piece of LilyPond
3578 input code. Other more complex functions are described in
3579 @rextend{Music functions}.
3582 * Substitution function syntax::
3583 * Common argument types::
3584 * Substitution function examples::
3587 @node Substitution function syntax
3588 @subsection Substitution function syntax
3590 Making a function that substitutes a variable into LilyPond
3591 code is easy. The general form of these functions is
3595 #(define-music-function (parser location @var{var1} @var{var2}...@var{vari}... )
3596 (@var{var1-type?} @var{var2-type?}...@var{vari-type?}...)
3605 @multitable @columnfractions .33 .66
3606 @item @var{vari} @tab @var{i}th variable
3607 @item @var{vari-type?} @tab type of @var{i}th variable
3608 @item @var{...music...} @tab normal LilyPond input, using
3609 variables as @code{#$var1}, etc.
3612 Common variable types are described in @ref{Common argument types}.
3613 A more complete description of variable types is found in
3614 @rextend{Music function syntax}.
3616 The @code{parser} and @code{location} arguments are mandatory,
3617 and are used in some advanced situations as described in
3618 @rextend{Music function syntax}. For substitution functions, just be sure
3624 @ref{Common argument types}.
3627 @rextend{Music function syntax}.
3629 @node Common argument types
3630 @subsection Common argument types
3632 In order to allow for error checking, the type of each argument
3633 that is passed to a music function must be defined. Some of the
3634 common types of variables are shown in the table below.
3636 The following input types may be used as variables in a music
3637 function. This list is not exhaustive;
3638 more information about possible variable types
3639 can be found in @rextend{Music function syntax}.
3641 @multitable @columnfractions .33 .66
3642 @headitem Input type @tab @var{vari-type?} notation
3643 @item Integer @tab @code{integer?}
3644 @item Float (decimal number) @tab @code{number?}
3645 @item Text string @tab @code{string?}
3646 @item Markup @tab @code{markup?}
3647 @item Music expression @tab @code{ly:music?}
3648 @item A Scheme pair @tab @code{pair?}
3654 @rextend {Music function syntax}.
3657 @file{lily/music-scheme.cc},
3661 @node Substitution function examples
3662 @subsection Substitution function examples
3664 This section introduces some substitution function examples. These
3665 are not intended to be exhaustive, but rather to demonstrate some
3666 of the possibilities of simple substitution functions.
3668 In the first example, a function is defined that simplifies
3669 setting the padding of a TextScript:
3671 @lilypond[quote,verbatim,ragged-right]
3672 padText = #(define-music-function (parser location padding) (number?)
3674 \once \override TextScript #'padding = #$padding
3678 c4^"piu mosso" b a b
3680 c4^"piu mosso" d e f
3682 c4^"piu mosso" fis a g
3686 In addition to numbers, we can use music expressions such
3687 as notes for arguments to music functions:
3689 @lilypond[quote,verbatim,ragged-right]
3690 custosNote = #(define-music-function (parser location note)
3693 \once \override Voice.NoteHead #'stencil =
3694 #ly:text-interface::print
3695 \once \override Voice.NoteHead #'text =
3696 \markup \musicglyph #"custodes.mensural.u0"
3697 \once \override Voice.Stem #'stencil = ##f
3701 { c' d' e' f' \custosNote g' }
3704 Substitution functions with multiple arguments can be defined:
3706 @lilypond[quote,verbatim,ragged-right]
3707 tempoPadded = #(define-music-function (parser location padding tempotext)
3710 \once \override Score.MetronomeMark #'padding = $padding
3711 \tempo \markup { \bold $tempotext }
3715 \tempo \markup { "Low tempo" }
3717 \tempoPadded #4.0 #"High tempo"