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13 @node Changing defaults
14 @chapter Changing defaults
16 The purpose of LilyPond's design is to provide the finest quality
17 output by default. Nevertheless, it may happen that you need to
18 change this default layout. The layout is controlled through a large
19 number of @q{knobs and switches} collectively called @q{properties}.
20 A tutorial introduction to accessing and modifying these properties
21 can be found in the Learning Manual, see @rlearning{Tweaking output}.
22 This should be read first. This chapter covers similar ground, but
23 in a style more appropriate to a reference manual.
25 @cindex Internals Reference
27 The definitive description of the controls available for tuning can
28 be found in a separate document: @rinternalsnamed{Top,the Internals
29 Reference}. That manual lists all the variables, functions and
30 options available in LilyPond. It is written as a HTML document,
32 @c leave the @uref as one long line.
33 @uref{http://@/lilypond@/.org/@/doc/@/stable/@/Documentation/@/internals/,on@/-line},
34 and is also included with the LilyPond documentation package.
36 Internally, LilyPond uses Scheme (a LISP dialect) to provide
37 infrastructure. Overriding layout decisions in effect accesses the
38 program internals, which requires Scheme input. Scheme elements are
39 introduced in a @file{.ly} file with the hash
40 mark@tie{}@code{#}.@footnote{@rextend{Scheme tutorial}, contains a
41 short tutorial on entering numbers, lists, strings, and symbols in
46 * Interpretation contexts::
47 * Explaining the Internals Reference::
48 * Modifying properties::
49 * Useful concepts and properties::
51 * Using music functions::
55 @node Interpretation contexts
56 @section Interpretation contexts
58 This section describes what contexts are, and how to modify them.
61 * Contexts explained::
63 * Keeping contexts alive::
64 * Modifying context plug-ins::
65 * Changing context default settings::
66 * Defining new contexts::
67 * Context layout order::
72 @rlearning{Contexts and engravers}.
75 @file{ly/engraver-init.ly},
76 @file{ly/performer-init.ly}.
79 @rlsr{Contexts and engravers}.
82 @rinternals{Contexts},
83 @rinternals{Engravers and Performers}.
86 @node Contexts explained
87 @subsection Contexts explained
90 @c TODO Rethink and rewrite
92 >> > > - list of contexts: my *danger unmaintainable*
93 >> > > alarm just went off. I'm
95 I knew it would... And leaving out some of them is perfectly fine
97 I do think that a list like this, with the main contexts and a
99 description of what they do (perhaps also with a note about what
101 behavior is associated with each of them, but this may be
103 should be there, and then we could simply list the remaining ones
105 further explanation and with links to the IR.
108 @c TODO Improve layout, order and consistency of wording -td
110 @c TODO Add introduction which explains contexts in generality -td
112 @c TODO Describe propagation of property values -td
114 Contexts are arranged hierarchically:
117 * Score - the master of all contexts::
118 * Top-level contexts - staff containers::
119 * Intermediate-level contexts - staves::
120 * Bottom-level contexts - voices::
123 @node Score - the master of all contexts
124 @unnumberedsubsubsec Score - the master of all contexts
126 This is the top level notation context. No other context can
127 contain a Score context. By default the Score context handles
128 the administration of time signatures and makes sure that items
129 such as clefs, time signatures, and key-signatures are aligned
132 A Score context is instantiated implicitly when a
133 @code{\score @{@dots{}@}} or @code{\layout @{@dots{}@}} block is
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 more complete descriptions rather than learning style
276 For scores with only one voice and one staff, contexts are
277 created automatically. For more complex scores, it is necessary to
278 create them by hand. There are three commands that do this.
283 The easiest command is @code{\new}, and it also the quickest to type.
284 It is prepended to a music expression, for example
288 @cindex Context, creating
291 \new @var{type} @var{music expression}
295 where @var{type} is a context name (like @code{Staff} or
296 @code{Voice}). This command creates a new context, and starts
297 interpreting the @var{music expression} with that.
299 A practical application of @code{\new} is a score with many
300 staves. Each part that should be on its own staff, is preceded with
303 @lilypond[quote,verbatim,relative=2,ragged-right]
310 The @code{\new} command may also give a name to the context,
313 \new @var{type} = @var{id} @var{music}
315 However, this user specified name is only used if there is no other
316 context already earlier with the same name.
322 Like @code{\new}, the @code{\context} command also directs a music
323 expression to a context object, but gives the context an explicit name. The
327 \context @var{type} = @var{id} @var{music}
330 This form will search for an existing context of type @var{type}
331 called @var{id}. If that context does not exist yet, a new
332 context with the specified name is created. This is useful if
333 the context is referred to later on. For example, when
334 setting lyrics the melody is in a named context
337 \context Voice = "@b{tenor}" @var{music}
341 so the texts can be properly aligned to its notes,
344 \new Lyrics \lyricsto "@b{tenor}" @var{lyrics}
349 Another possible use of named contexts is funneling two different
350 music expressions into one context. In the following example,
351 articulations and notes are entered separately,
355 arts = @{ s4-. s4-> @}
358 They are combined by sending both to the same @code{Voice} context,
362 \new Staff \context Voice = "A" \music
363 \context Voice = "A" \arts
366 @lilypond[quote,ragged-right]
370 \new Staff \context Voice = "A" \music
371 \context Voice = "A" \arts
375 With this mechanism, it is possible to define an Urtext (original
376 edition), with the option to put several distinct articulations on the
379 @cindex creating contexts
382 The third command for creating contexts is
384 \context @var{type} @var{music}
389 This is similar to @code{\context} with @code{= @var{id}}, but matches
390 any context of type @var{type}, regardless of its given name.
392 This variant is used with music expressions that can be interpreted at
393 several levels. For example, the @code{\applyOutput} command (see
394 @rextend{Running a function on all layout objects}). Without an explicit
395 @code{\context}, it is usually applied to @code{Voice}
398 \applyOutput #'@var{context} #@var{function} % apply to Voice
401 To have it interpreted at the @code{Score} or @code{Staff} level use
405 \applyOutput #'Score #@var{function}
406 \applyOutput #'Staff #@var{function}
411 @node Keeping contexts alive
412 @subsection Keeping contexts alive
414 @cindex contexts, keeping alive
415 @cindex contexts, lifetime
417 Contexts are usually terminated at the first musical moment in
418 which they have nothing to do. So @code{Voice} contexts die as
419 soon as they contain no events; @code{Staff} contexts die as soon
420 as all the @code{Voice} contexts within them contain no events; etc.
421 This can cause difficulties if earlier contexts which have died
422 have to be referenced, for example, when changing staves with
423 @code{\change} commands, associating lyrics with a voice with
424 @code{\lyricsto} commands, or when adding further musical events to
427 There is an exception to this general rule: just one of the
428 @code{Voice} contexts in a @code{Staff} context or in a
429 @code{<<...>>} construct will always persist to the end of the
430 enclosing @code{Staff} context or @code{<<...>>} construct, even
431 though there may be periods when it has nothing to do. The context
432 to persist in this way will be the first one encountered in the
433 first enclosed @code{@{...@}} construct, ignoring any in enclosed
434 @code{<<...>>} constructs.
436 Any context can be kept alive by ensuring it has something to do at
437 every musical moment. @code{Staff} contexts are kept alive by
438 ensuring one of their voices is kept alive. One way of doing this
439 is to add spacer rests to a voice in parallel with the real music.
440 These need to be added to every @code{Voice} context which needs to
441 be kept alive. If several voices are to be used sporadically it is
442 safest to keep them all alive rather than attempting to rely on the
443 exceptions mentioned above.
445 In the following example, both voice A and voice B are kept alive
446 in this way for the duration of the piece:
448 @lilypond[quote,verbatim]
449 musicA = \relative c'' { d4 d d d }
450 musicB = \relative c'' { g4 g g g }
453 \new Voice = "A" { s1*5 } % Keep Voice "A" alive for 5 bars
454 \new Voice = "B" { s1*5 } % Keep Voice "B" alive for 5 bars
459 \context Voice = "A" {
463 \context Voice = "B" {
467 \context Voice = "A" { \musicA }
468 \context Voice = "B" { \musicB }
469 \context Voice = "A" { \musicA }
480 @cindex lyrics, aligning with sporadic melody
482 The following example shows how a sporadic melody line with lyrics
483 might be written using this approach. In a real situation the
484 melody and accompaniment would consist of several different
487 @lilypond[quote,verbatim]
488 melody = \relative c'' { a4 a a a }
489 accompaniment = \relative c' { d4 d d d }
490 words = \lyricmode { These words fol -- low the mel -- o -- dy }
493 \new Staff = "music" {
495 \new Voice = "melody" {
497 s1*4 % Keep Voice "melody" alive for 4 bars
500 \new Voice = "accompaniment" {
505 \context Voice = "melody" { \melody }
506 \context Voice = "accompaniment" { \accompaniment }
508 \context Voice = "accompaniment" { \accompaniment }
510 \context Voice = "melody" { \melody }
511 \context Voice = "accompaniment" { \accompaniment }
516 \new Lyrics \with { alignAboveContext = #"music" }
517 \lyricsto "melody" { \words }
522 An alternative way, which may be better in many circumstances, is
523 to keep the melody line alive by simply including spacer notes to
524 line it up correctly with the accompaniment:
526 @lilypond[quote,verbatim]
527 melody = \relative c'' {
533 accompaniment = \relative c' {
539 words = \lyricmode { These words fol -- low the mel -- o -- dy }
543 \new Staff = "music" {
545 \new Voice = "melody" {
549 \new Voice = "accompaniment" {
555 \new Lyrics \with { alignAboveContext = #"music" }
556 \lyricsto "melody" { \words }
562 @node Modifying context plug-ins
563 @subsection Modifying context plug-ins
565 @c TODO Should this be Modifying engravers or Modifying contexts?
567 Notation contexts (like @code{Score} and @code{Staff}) not only store
568 properties, they also contain plug-ins called @q{engravers} that create
569 notation elements. For example, the @code{Voice} context contains a
570 @code{Note_heads_engraver} and the @code{Staff} context contains a
573 For a full a description of each plug-in, see
575 @rinternals{Engravers and Performers}.
578 Internals Reference @expansion{} Translation @expansion{} Engravers.
580 Every context described in
582 @rinternals{Contexts}
585 Internals Reference @expansion{} Translation @expansion{} Context.
587 lists the engravers used for that context.
590 It can be useful to shuffle around these plug-ins. This is done by
591 starting a new context with @code{\new} or @code{\context}, and
597 \new @var{context} \with @{
610 where the @dots{} should be the name of an engraver. Here is a simple
611 example which removes @code{Time_signature_engraver} and
612 @code{Clef_engraver} from a @code{Staff} context,
614 @lilypond[quote,relative=1,verbatim]
620 \remove "Time_signature_engraver"
621 \remove "Clef_engraver"
628 In the second staff there are no time signature or clef symbols. This
629 is a rather crude method of making objects disappear since it will affect
630 the entire staff. This method also influences the spacing, which may or
631 may not be desirable. More sophisticated methods of blanking objects
632 are shown in @rlearning{Visibility and color of objects}.
634 The next example shows a practical application. Bar lines and time
635 signatures are normally synchronized across the score. This is done
636 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
637 This plug-in keeps an administration of time signature, location
638 within the measure, etc. By moving these engraver from @code{Score} to
639 @code{Staff} context, we can have a score where each staff has its own
642 @cindex polymetric scores
643 @cindex Time signatures, multiple
645 @lilypond[quote,verbatim]
649 \consists "Timing_translator"
650 \consists "Default_bar_line_engraver"
656 \consists "Timing_translator"
657 \consists "Default_bar_line_engraver"
666 \remove "Timing_translator"
667 \remove "Default_bar_line_engraver"
675 Usually the order in which the engravers are specified
676 does not matter, but in a few special cases the order
677 is important, for example where one engraver writes
678 a property and another reads it, or where one engraver
679 creates a grob and another must process it. The order in
680 which the engravers are specified is the order in which
681 they are called to carry out their processing.
683 The following orderings are important: the
684 @code{Bar_engraver} must normally be first, and
685 the @code{New_fingering_engraver} must come before
686 the @code{Script_column_engraver}. There may be others
687 with ordering dependencies.
689 @node Changing context default settings
690 @subsection Changing context default settings
692 The context settings which are to be used by default in
693 @code{Score}, @code{Staff} and @code{Voice} contexts may be specified
694 in a @code{\layout} block, as illustrated in the following example.
695 The @code{\layout} block should be placed within the @code{\score}
696 block to which it is to apply, but outside any music.
698 Note that the @code{\set} command itself and the context must be
699 omitted when the context default values are specified in this way:
701 @lilypond[quote,verbatim]
704 a4^"Really small, thicker stems, no time signature" a a a
711 \override Stem #'thickness = #4.0
712 \remove "Time_signature_engraver"
718 In this example, the @code{\Staff} command specifies that the
719 subsequent specifications are to be applied to all staves within
722 Modifications can be made to the @code{Score} context or all
723 @code{Voice} contexts in a similar way.
725 Context changes can be placed in a variable and applied to a
726 @code{\context} definition by prepending the modification with
728 @lilypond[quote,verbatim]
731 \override Stem #'thickness = #4.0
732 \remove "Time_signature_engraver"
737 \override Stem #'thickness = #-2.0
740 melody = \relative c'' {
749 s4^"Small, thicker stems, no time signature"
765 @c TODO: add \with in here.
769 @node Defining new contexts
770 @subsection Defining new contexts
772 @cindex contexts, defining new
773 @cindex engravers, including in contexts
788 Specific contexts, like @code{Staff} and @code{Voice}, are made of
789 simple building blocks. It is possible to create new types of
790 contexts with different combinations of engraver plug-ins.
792 The next example shows how to build a different type of
793 @code{Voice} context from scratch. It will be similar to
794 @code{Voice}, but only prints centered slash note heads. It can be used
795 to indicate improvisation in jazz pieces,
797 @lilypond[quote,ragged-right]
800 \type "Engraver_group"
801 \consists "Note_heads_engraver"
802 \consists "Rhythmic_column_engraver"
803 \consists "Text_engraver"
804 \consists Pitch_squash_engraver
805 squashedPosition = #0
806 \override NoteHead #'style = #'slash
807 \override Stem #'transparent = ##t
808 \override Flag #'transparent = ##t
812 \accepts "ImproVoice"
816 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
817 c4 c^"undress" c_"while playing :)" c }
823 These settings are defined within a @code{\context} block inside a
824 @code{\layout} block,
834 In the following discussion, the example input shown should go in place
835 of the @dots{} in the previous fragment.
837 First it is necessary to define a name for the new context:
843 Since it is similar to the @code{Voice}, we want commands that work
844 on (existing) @code{Voice}s to remain working. This is achieved by
845 giving the new context an alias @code{Voice},
851 The context will print notes and instructive texts, so we need to add
852 the engravers which provide this functionality,
855 \consists Note_heads_engraver
856 \consists Text_engraver
859 but we only need this on the center line,
862 \consists Pitch_squash_engraver
863 squashedPosition = #0
866 The @rinternals{Pitch_squash_engraver} modifies note heads (created
867 by @rinternals{Note_heads_engraver}) and sets their vertical
868 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
871 The notes look like a slash, and have no stem,
874 \override NoteHead #'style = #'slash
875 \override Stem #'transparent = ##t
876 \override Flag #'transparent = ##t
879 All these plug-ins have to cooperate, and this is achieved with a
880 special plug-in, which must be marked with the keyword @code{\type}.
881 This should always be @code{Engraver_group}.
884 \type "Engraver_group"
892 \type "Engraver_group"
893 \consists "Note_heads_engraver"
894 \consists "Text_engraver"
895 \consists Pitch_squash_engraver
896 squashedPosition = #0
897 \override NoteHead #'style = #'slash
898 \override Stem #'transparent = ##t
899 \override Flag #'transparent = ##t
905 Contexts form hierarchies. We want to hang the @code{ImproVoice}
906 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
907 modify the @code{Staff} definition with the @code{\accepts}
918 The opposite of @code{\accepts} is @code{\denies},
919 which is sometimes needed when reusing existing context definitions.
921 Putting both into a @code{\layout} block, like
931 \accepts "ImproVoice"
936 Then the output at the start of this subsection can be entered as
944 c c_"while playing :)"
951 @node Context layout order
952 @subsection Context layout order
954 @cindex contexts, layout order
958 Contexts are normally positioned in a system from top to bottom
959 in the order in which they are encountered in the input file. When
960 contexts are nested, the outer context will include inner nested
961 contexts as specified in the input file, provided the inner contexts
962 are included in the outer context's @qq{accepts} list. Nested
963 contexts which are not included in the outer context's @qq{accepts}
964 list will be repositioned below the outer context rather than nested
967 The @qq{accepts} list of a context can be changed with the
968 @code{\accepts} and @code{\denies} commands. @code{\accepts} adds a
969 context to the @qq{accepts} list and @code{\denies} removes a context
970 from the list. For example, it would not normally be desirable for
971 chord names to be nested within a @code{Staff} context, so the
972 @code{ChordNames} context is not included by default in the @qq{accepts}
973 list of the @code{Staff} context, but if this were to be required it can
976 @lilypond[verbatim,quote]
980 \chords { d1:m7 b1:min7.5- }
985 @lilypond[verbatim,quote]
989 \chords { d1:m7 b1:min7.5- }
994 \accepts "ChordNames"
1000 @code{\denies} is mainly used when a new context is being based on
1001 another, but the required nesting differs. For example, the
1002 @code{VaticanaStaff} context is based on the @code{Staff} context, but
1003 with the @code{VaticanaVoice} context substituted for the @code{Voice}
1004 context in the @qq{accepts} list.
1006 Note that a context will be silently created implicitly if a command
1007 is encountered when there is no suitable context available to
1008 contain it. This can give rise to unexpected new staves or scores.
1010 @cindex alignAboveContext
1011 @cindex alignBelowContext
1012 @funindex alignAboveContext
1013 @funindex alignBelowContext
1015 Sometimes a context is required to exist for just a brief period, a
1016 good example being the staff context for an ossia. This is usually
1017 achieved by introducing the context definition at the appropriate
1018 place in parallel with corresponding section of the main music.
1019 By default, the temporary context will be placed below all the
1020 existing contexts. To reposition it above the context called
1021 @qq{main}, it should be defined like this:
1024 @code{\new Staff \with @{ alignAboveContext = #"main" @} }
1027 A similar situation arises when positioning a temporary lyrics
1028 context within a multi-staved layout such as a @code{ChoirStaff},
1029 for example, when adding a second verse to a repeated section.
1030 By default the temporary lyrics context will be placed beneath the
1031 lower staves. By defining the temporary lyrics context with
1032 @code{alignBelowContext} it can be positioned correctly beneath
1033 the (named) lyrics context containing the first verse.
1035 Examples showing this repositioning of temporary contexts can be
1036 found elsewhere --- see @rlearning{Nesting music expressions},
1037 @ref{Modifying single staves} and @ref{Techniques specific to lyrics}.
1041 @rlearning{Nesting music expressions}.
1044 @ref{Modifying single staves},
1045 @ref{Techniques specific to lyrics}.
1048 @rprogram{An extra staff appears}.
1051 @file{ly/engraver-init.ly}.
1054 @node Explaining the Internals Reference
1055 @section Explaining the Internals Reference
1058 * Navigating the program reference::
1059 * Layout interfaces::
1060 * Determining the grob property::
1061 * Naming conventions::
1064 @node Navigating the program reference
1065 @subsection Navigating the program reference
1067 @c TODO remove this (it's in the LM)
1068 @c Replace with more factual directions
1070 Suppose we want to move the fingering indication in the fragment
1073 @lilypond[quote,relative=2,verbatim]
1079 If you visit the documentation on fingering instructions (in
1080 @ref{Fingering instructions}), you will notice:
1085 Internals Reference: @rinternals{Fingering}.
1090 @c outdated info; probably will delete.
1092 This fragment points to two parts of the program reference: a page
1093 on @code{FingeringEvent} and one on @code{Fingering}.
1095 The page on @code{FingeringEvent} describes the properties of the music
1096 expression for the input @w{@code{-2}}. The page contains many links
1097 forward. For example, it says
1100 Accepted by: @rinternals{Fingering_engraver},
1104 That link brings us to the documentation for the Engraver, the
1108 This engraver creates the following layout objects: @rinternals{Fingering}.
1111 In other words, once the @code{FingeringEvent}s are interpreted, the
1112 @code{Fingering_engraver} plug-in will process them.
1116 @c I can't figure out what this is supposed to mean. -gp
1118 The @code{Fingering_engraver} is also listed to create
1119 @rinternals{Fingering} objects,
1121 @c old info? it doesn't make any sense to me with our current docs.
1123 second bit of information listed under @b{See also} in the Notation
1128 The programmer's reference is available as an HTML document. It is
1129 highly recommended that you read it in HTML form, either online or
1130 by downloading the HTML documentation. This section will be much more
1131 difficult to understand if you are using the
1135 Follow the link to @rinternals{Fingering}. At the top of the
1139 Fingering objects are created by: @rinternals{Fingering_engraver} and
1140 @rinternals{New_fingering_engraver}.
1143 By following related links inside the program reference, we can follow the
1144 flow of information within the program:
1148 @item @rinternals{Fingering}:
1149 @rinternals{Fingering} objects are created by:
1150 @rinternals{Fingering_engraver}
1152 @item @rinternals{Fingering_engraver}:
1153 Music types accepted: @rinternals{fingering-event}
1155 @item @rinternals{fingering-event}:
1156 Music event type @code{fingering-event} is in Music expressions named
1157 @rinternals{FingeringEvent}
1160 This path goes against the flow of information in the program: it
1161 starts from the output, and ends at the input event. You could
1162 also start at an input event, and read with the flow of
1163 information, eventually ending up at the output object(s).
1165 The program reference can also be browsed like a normal document. It
1166 contains chapters on
1168 @rinternals{Music definitions},
1171 @code{Music definitions}
1173 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1174 chapter lists all the definitions used and all properties that may be
1178 @node Layout interfaces
1179 @subsection Layout interfaces
1181 @cindex interface, layout
1182 @cindex layout interface
1185 The HTML page that we found in the previous section describes the
1186 layout object called @rinternals{Fingering}. Such an object is a
1187 symbol within the score. It has properties that store numbers (like
1188 thicknesses and directions), but also pointers to related objects. A
1189 layout object is also called a @emph{Grob}, which is short for Graphical
1190 Object. For more details about Grobs, see @rinternals{grob-interface}.
1192 The page for @code{Fingering} lists the definitions for the
1193 @code{Fingering} object. For example, the page says
1196 @code{padding} (dimension, in staff space):
1202 which means that the number will be kept at a distance of at least 0.5
1206 Each layout object may have several functions as a notational or
1207 typographical element. For example, the Fingering object
1208 has the following aspects
1212 Its size is independent of the horizontal spacing, unlike slurs or beams.
1215 It is a piece of text. Granted, it is usually a very short text.
1218 That piece of text is typeset with a font, unlike slurs or beams.
1221 Horizontally, the center of the symbol should be aligned to the
1222 center of the note head.
1225 Vertically, the symbol is placed next to the note and the staff.
1228 The vertical position is also coordinated with other superscript
1229 and subscript symbols.
1232 Each of these aspects is captured in so-called @emph{interface}s,
1233 which are listed on the @rinternals{Fingering} page at the bottom
1236 This object supports the following interfaces:
1237 @rinternals{item-interface},
1238 @rinternals{self-alignment-interface},
1239 @rinternals{side-position-interface}, @rinternals{text-interface},
1240 @rinternals{text-script-interface}, @rinternals{font-interface},
1241 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1244 Clicking any of the links will take you to the page of the respective
1245 object interface. Each interface has a number of properties. Some of
1246 them are not user-serviceable (@q{Internal properties}), but others
1249 We have been talking of @emph{the} @code{Fingering} object, but actually it
1250 does not amount to much. The initialization file (see
1251 @rlearning{Other sources of information})
1252 @file{scm/define-grobs.scm} shows the soul of the @q{object},
1257 (avoid-slur . around)
1258 (slur-padding . 0.2)
1259 (staff-padding . 0.5)
1260 (self-alignment-X . 0)
1261 (self-alignment-Y . 0)
1262 (script-priority . 100)
1263 (stencil . ,ly:text-interface::print)
1264 (direction . ,ly:script-interface::calc-direction)
1265 (font-encoding . fetaText)
1266 (font-size . -5) ; don't overlap when next to heads.
1267 (meta . ((class . Item)
1268 (interfaces . (finger-interface
1270 text-script-interface
1272 side-position-interface
1273 self-alignment-interface
1274 item-interface))))))
1278 As you can see, the @code{Fingering} object is nothing more than a
1279 bunch of variable settings, and the webpage in the Internals Reference
1280 is directly generated from this definition.
1283 @node Determining the grob property
1284 @subsection Determining the grob property
1286 @c TODO remove this (it's in the LM)
1287 @c Replace with more factual directions
1289 Recall that we wanted to change the position of the @b{2} in
1291 @lilypond[quote,relative=2,verbatim]
1297 Since the @b{2} is vertically positioned next to its note, we have to
1298 meddle with the interface associated with this positioning. This is
1299 done using @code{side-position-interface}. The page for this interface
1303 @code{side-position-interface}
1305 Position a victim object (this one) next to other objects (the
1306 support). The property @code{direction} signifies where to put the
1307 victim object relative to the support (left or right, up or down?)
1312 Below this description, the variable @code{padding} is described as
1317 (dimension, in staff space)
1319 Add this much extra space between objects that are next to each other.
1323 By increasing the value of @code{padding}, we can move the
1324 fingering away from the note head. The following command inserts
1325 3 staff spaces of white
1326 between the note and the fingering:
1328 \once \override Voice.Fingering #'padding = #3
1331 Inserting this command before the Fingering object is created,
1332 i.e., before @code{c2}, yields the following result:
1334 @lilypond[quote,relative=2,verbatim]
1335 \once \override Voice.Fingering #'padding = #3
1342 In this case, the context for this tweak is @code{Voice}. This
1343 fact can also be deduced from the program reference, for the page for
1344 the @rinternals{Fingering_engraver} plug-in says
1347 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1351 @node Naming conventions
1352 @subsection Naming conventions
1354 Another thing that is needed, is an overview of the various naming
1358 @item scheme functions: lowercase-with-hyphens (incl. one-word
1360 @item scheme functions: ly:plus-scheme-style
1361 @item music events, music classes and music properties:
1363 @item Grob interfaces: scheme-style
1364 @item backend properties: scheme-style (but X and Y!)
1365 @item contexts (and MusicExpressions and grobs): Capitalized or
1367 @item context properties: lowercaseFollowedByCamelCase
1369 Capitalized_followed_by_lowercase_and_with_underscores
1372 Questions to be answered:
1374 @item Which of these are conventions and which are rules?
1375 @item Which are rules of the underlying language, and which are
1379 @node Modifying properties
1380 @section Modifying properties
1382 @c TODO change the menu and subsection node names to use
1383 @c backslash once the new macro to handle the refs
1384 @c is available. Need to find and change all refs at
1385 @c the same time. -td
1388 * Overview of modifying properties::
1390 * The override command::
1391 * The tweak command::
1392 * set versus override::
1393 * Modifying alists::
1397 @node Overview of modifying properties
1398 @subsection Overview of modifying properties
1400 Each context is responsible for creating certain types of graphical
1401 objects. The settings used for printing these objects are also stored by
1402 context. By changing these settings, the appearance of objects can be
1405 There are two different kinds of properties stored in contexts:
1406 context properties and grob properties. Context properties are
1407 properties that apply to the context as a whole and control
1408 how the context itself is displayed. In contrast, grob properties
1409 apply to specific grob types that will be displayed in the context.
1411 The @code{\set} and @code{\unset} commands are used to change values
1412 for context properties. The @code{\override} and @code{\revert}
1413 commands are used to change values for grob properties.
1416 The syntax for this is
1419 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1422 Here @var{name} is the name of a graphical object, like
1423 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1424 variable of the formatting system (@q{grob property} or @q{layout
1425 property}). The latter is a symbol, so it must be quoted. The
1426 subsection @ref{Modifying properties}, explains what to fill in
1427 for @var{name}, @var{property}, and @var{value}. Here we only
1428 discuss the functionality of this command.
1433 \override Staff.Stem #'thickness = #4.0
1437 makes stems thicker (the default is 1.3, with staff line thickness as a
1438 unit). Since the command specifies @code{Staff} as context, it only
1439 applies to the current staff. Other staves will keep their normal
1440 appearance. Here we see the command in action:
1442 @lilypond[quote,verbatim,relative=2]
1444 \override Staff.Stem #'thickness = #4.0
1450 The @code{\override} command changes the definition of the @code{Stem}
1451 within the current @code{Staff}. After the command is interpreted
1452 all stems are thickened.
1454 Analogous to @code{\set}, the @var{context} argument may be left out,
1455 causing the default context @code{Voice} to be used. Adding
1456 @code{\once} applies the change during one timestep only.
1458 @lilypond[quote,verbatim,relative=2]
1460 \once \override Stem #'thickness = #4.0
1465 The @code{\override} must be done before the object is
1466 started. Therefore, when altering @emph{Spanner} objects such as slurs
1467 or beams, the @code{\override} command must be executed at the moment
1468 when the object is created. In this example,
1470 @lilypond[quote,verbatim,relative=2]
1471 \override Slur #'thickness = #3.0
1473 \override Beam #'beam-thickness = #0.6
1478 the slur is fatter but the beam is not. This is because the command for
1479 @code{Beam} comes after the Beam is started, so it has no effect.
1481 Analogous to @code{\unset}, the @code{\revert} command for a context
1482 undoes an @code{\override} command; like with @code{\unset}, it only
1483 affects settings that were made in the same context. In other words, the
1484 @code{\revert} in the next example does not do anything.
1487 \override Voice.Stem #'thickness = #4.0
1488 \revert Staff.Stem #'thickness
1491 Some tweakable options are called @q{subproperties} and reside inside
1492 properties. To tweak those, use commands of the form
1494 @c leave this as a long long
1496 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1503 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1509 Internals Reference:
1510 @rinternals{Backend},
1511 @rinternals{All layout objects},
1512 @rinternals{OverrideProperty},
1513 @rinternals{RevertProperty},
1514 @rinternals{PropertySet}.
1517 The back-end is not very strict in type-checking object properties.
1518 Cyclic references in Scheme values for properties can cause hangs
1519 or crashes, or both.
1522 @node The set command
1523 @subsection The @code{@bs{}set} command
1527 @cindex changing properties
1529 Each context has a set of @emph{properties}, variables contained
1530 in that context. Context properties are changed with the @code{\set}
1531 command, which has the following syntax:
1534 \set @var{context}.@var{property} = #@var{value}
1537 @var{value} is a Scheme object, which is why it must be preceded by
1538 the @code{#}@tie{}character.
1540 Contexts properties are usually named in
1541 @code{studlyCaps}. They mostly control the translation from
1542 music to notation, e.g. @code{localKeySignature} (for determining
1543 whether to print accidentals), or @code{measurePosition} (for
1544 determining when to print a bar line). Context properties can
1545 change value over time while interpreting a piece of music;
1546 @code{measurePosition} is an obvious example of
1547 this. Context properties are modified with @code{\set}.
1549 For example, multimeasure rests will be combined into a single bar
1550 if the context property @code{skipBars} is set to @code{#t}:
1552 @lilypond[quote,verbatim,relative=2]
1554 \set Score.skipBars = ##t
1558 If the @var{context} argument is left out, then the property will be
1559 set in the current bottom context (typically @code{ChordNames},
1560 @code{Voice}, @code{TabVoice}, or @code{Lyrics}).
1562 @lilypond[quote,verbatim,relative=2]
1563 \set Score.autoBeaming = ##f
1567 \set autoBeaming = ##t
1575 The change is applied @q{on-the-fly}, during the music, so that the
1576 setting only affects the second group of eighth notes.
1578 Note that the bottom-most context does not always contain the property
1579 that you wish to change -- for example, attempting to set the
1580 @code{skipBars} property of the default bottom context, in this case
1581 @code{Voice}, will have no effect, because skipBars is a property of
1582 the @code{Score} context.
1584 @lilypond[quote,verbatim,relative=2]
1590 Contexts are hierarchical, so if an enclosing context was specified, for
1591 example @code{Staff}, then the change would also apply to all
1592 @code{Voice}s in the current staff.
1596 The @code{\unset} command:
1599 \unset @var{context}.@var{property}
1603 is used to remove the definition of @var{property} from
1604 @var{context}. This command removes
1605 the definition only if it is set in @var{context}.
1606 Properties that have been set in enclosing contexts will
1607 not be altered by an unset in an enclosed context:
1609 @lilypond[quote,verbatim,relative=2]
1610 \set Score.autoBeaming = ##t
1615 \unset Score.autoBeaming
1623 Like @code{\set}, the @var{context} argument does not have to be
1624 specified for a bottom context, so the two statements
1627 \set Voice.autoBeaming = ##t
1628 \set autoBeaming = ##t
1632 are equivalent if the current bottom context is @code{Voice}.
1636 Preceding a @code{\set} command by @code{\once} makes the
1637 setting apply to only a single time-step:
1639 @lilypond[quote,verbatim,relative=2]
1641 \once \set fontSize = #4.7
1646 A full description of all available context properties is in the
1647 internals reference, see
1649 @rinternals{Tunable context properties}.
1652 Translation @expansion{} Tunable context properties.
1656 Internals Reference:
1657 @rinternals{Tunable context properties}.
1659 @cindex grob properties
1660 @cindex properties, grob
1664 @node The override command
1665 @subsection The @code{\override} command
1667 There is a special type of context property: the grob
1668 description. Grob descriptions are named in @code{StudlyCaps}
1669 (starting with capital letters). They contain the
1670 @q{default settings} for a particular kind of grob as an
1671 association list. See @file{scm/define-grobs.scm}
1672 to see the settings for each grob description. Grob descriptions
1673 are modified with @code{\override}.
1675 @code{\override} is actually a shorthand;
1678 \override @var{context}.@var{GrobName} #'@var{property} = #@var{value}
1682 is more or less equivalent to
1684 @c leave this long line -gp
1686 \set @var{context}.@var{GrobName} =
1687 #(cons (cons '@var{property} @var{value})
1688 <previous value of @var{context}.@var{GrobName}>)
1691 The value of @code{context}.@code{GrobName} (the alist) is used to initialize
1692 the properties of individual grobs. Grobs have
1693 properties, named in Scheme style, with
1694 @code{dashed-words}. The values of grob properties change
1695 during the formatting process: formatting basically amounts
1696 to computing properties using callback functions.
1698 For example, we can increase the thickness of a note stem by
1699 overriding the @code{thickness} property of the @code{Stem}
1702 @lilypond[quote,verbatim,relative=2]
1704 \override Voice.Stem #'thickness = #3.0
1708 If no context is specified in an @code{\override}, the bottom
1711 @lilypond[quote,verbatim,relative=2]
1712 { \override Staff.Stem #'thickness = #3.0
1716 \override Stem #'thickness = #0.5
1726 @cindex reverting overrides
1727 @cindex overrides, reverting
1729 The effects of @code{\override} can be undone by @code{\revert}:
1731 @lilypond[quote,verbatim,relative=2]
1733 \override Voice.Stem #'thickness = #3.0
1735 \revert Voice.Stem #'thickness
1739 The effects of @code{\override} and @code{\revert} apply to all
1740 grobs in the affected context from the current time forward:
1742 @lilypond[quote,verbatim,relative=2]
1747 \override Staff.Stem #'thickness = #3.0
1751 \revert Staff.Stem #'thickness
1759 @cindex overriding for only one moment
1761 @code{\once} can be used with @code{\override}
1762 to affect only the current time step:
1764 @lilypond[quote,verbatim,relative=2]
1768 \override Stem #'thickness = #3.0
1772 \once \override Stem #'thickness = #3.0
1781 Commands which change output generally look like
1784 \override Voice.Stem #'thickness = #3.0
1788 To construct this tweak we must determine these bits of information:
1791 @item the context: here @code{Voice}.
1792 @item the layout object: here @code{Stem}.
1793 @item the layout property: here @code{thickness}.
1794 @item a sensible value: here @code{3.0}.
1797 Some tweakable options are called @q{subproperties} and reside inside
1798 properties. To tweak those, use commands in the form
1801 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1804 @cindex internal documentation
1805 @cindex finding graphical objects
1806 @cindex graphical object descriptions
1809 @cindex internal documentation
1811 For many properties, regardless of the data type of the property, setting the
1812 property to false (@code{#f}) will result in turning it off, causing
1813 LilyPond to ignore that property entirely. This is particularly useful for
1814 turning off grob properties which may otherwise be causing problems.
1816 We demonstrate how to glean this information from the notation manual
1817 and the program reference.
1821 Internals Reference:
1822 @rinternals{Backend}
1825 @node The tweak command
1826 @subsection The @code{\tweak} command
1831 Changing grob properties
1832 with @code{\override} causes the changes to apply to all of the
1833 given grobs in the context at the moment the change applies.
1834 Sometimes, however, it is desirable to have changes apply to just
1835 one grob, rather than to all grobs in the affected context. This is
1836 accomplished with the @code{\tweak} command, which has the following
1840 \tweak @var{layout-object} #'@var{grob-property} @var{value}
1843 Specifying @var{layout-object} is optional.
1844 The @code{\tweak} command applies to the music object that immediately
1845 follows @var{value} in the music stream.
1848 In some cases, it is possible to take a short-cut for tuning
1849 graphical objects. For objects that are created directly from
1850 an item in the input file, you can use the @code{\tweak} command.
1853 @lilypond[relative=2,verbatim,quote]
1858 \tweak #'duration-log #1
1861 -\tweak #'padding #8
1867 But the main use of the @code{\tweak} command is to modify just
1868 one of a number of notation elements which start at the same musical
1869 moment, like the notes of a chord, or tuplet brackets which start
1872 The @code{\tweak} command sets a property in the following object
1873 directly, without requiring the grob name or context to be
1874 specified. For this to work, it is necessary for the @code{\tweak}
1875 command to remain immediately adjacent to the object to which it is
1876 to apply after the input file has been converted to a music stream.
1877 This is often not the case, as many additional elements are inserted
1878 into the music stream implicitly. For example, when a note which is
1879 not part of a chord is processed, LilyPond implicitly inserts a
1880 @code{ChordEvent} event before the note, so separating the tweak
1881 from the note. However, if chord symbols are placed round the
1882 tweak and the note, the @code{\tweak} command comes after the
1883 @code{ChordEvent} in the music stream, so remaining adjacent to the
1884 note, and able to modify it.
1888 @lilypond[relative=2,verbatim,quote]
1889 <\tweak #'color #red c>4
1895 @lilypond[relative=2,verbatim,quote]
1896 \tweak #'color #red c4
1901 For an introduction to the syntax and uses of the tweak command
1902 see @rlearning{Tweaking methods}.
1904 When several similar items are placed at the same musical moment,
1905 the @code{\override} command cannot be used to modify just one of
1906 them -- this is where the @code{\tweak} command must be used.
1907 Items which may appear more than once at the same musical moment
1908 include the following:
1910 @c TODO expand to include any further uses of \tweak
1912 @item note heads of notes inside a chord
1913 @item articulation signs on a single note
1914 @item ties between notes in a chord
1915 @item tuplet brackets starting at the same time
1918 @c TODO add examples of these
1920 @cindex chord, modifying one note in
1922 In this example, the color of one note head and the type of another
1923 note head are modified within a single chord:
1925 @lilypond[relative=2,verbatim,quote]
1930 \tweak #'duration-log #1
1935 @code{\tweak} can be used to modify slurs:
1937 @lilypond[verbatim,quote,relative=1]
1938 c-\tweak #'thickness #5 ( d e f)
1942 For the @code{\tweak} command to work, it must
1943 remain immediately adjacent to the object to which it is
1944 to apply after the input file has been converted to a music stream.
1945 Tweaking a whole chord does not do anything since its music event
1946 only acts as a container, and all layout objects are created from events
1947 inside of the @code{EventChord}:
1949 @lilypond[relative=2,verbatim,quote]
1950 \tweak #'color #red c4
1951 \tweak #'color #red <c e>4
1952 <\tweak #'color #red c e>4
1955 The simple @code{\tweak} command cannot be used to modify any object
1956 that is not directly created from the input. In particular
1957 it will not affect stems, automatic
1958 beams or accidentals, since these are generated later by
1959 @code{NoteHead} layout objects rather than by music elements in the
1962 Such indirectly created layout objects can be tweaked using the explicit
1963 form of the @code{\tweak} command:
1965 @lilypond[relative=2,verbatim,quote]
1966 \tweak Stem #'color #red
1967 \tweak Beam #'color #green c8 e
1968 <c e \tweak Accidental #'font-size #-3 ges>4
1971 @code{\tweak} cannot be used to modify clefs or time
1972 signatures, since these become separated from any preceding
1973 @code{\tweak} command in the input stream by the automatic
1974 insertion of extra elements required to specify the context.
1976 Several @code{\tweak} commands may be placed before a
1977 notational element -- all affect it:
1979 @lilypond[verbatim,quote,relative=1]
1981 -\tweak #'style #'dashed-line
1982 -\tweak #'dash-fraction #0.2
1983 -\tweak #'thickness #3
1984 -\tweak #'color #red
1989 The music stream which is generated from a section of an input file,
1990 including any automatically inserted elements, may be examined,
1991 see @rextend{Displaying music expressions}. This may be helpful in
1992 determining what may be modified by a @code{\tweak} command, or
1993 in determining how to adjust the input to make a @code{\tweak}
1998 @rlearning{Tweaking methods}.
2001 @rextend{Displaying music expressions}.
2005 @cindex tweaking control points
2006 @cindex control points, tweaking
2008 The @code{\tweak} command will apply to only the first of several
2009 generated ties in a chord.
2012 @node set versus override
2013 @subsection @code{\set} vs. @code{\override}
2015 @c TODO -- This section is probably unnecessary now.
2018 We have seen two methods of changing properties: @code{\set} and
2019 @code{\override}. There are actually two different kinds of
2022 @code{fontSize} is a special property: it is equivalent to
2023 entering @code{\override ... #'font-size} for all pertinent
2024 objects. Since this is a common change, the special
2025 property (modified with @code{\set}) was created.
2030 @node Modifying alists
2031 @subsection Modifying alists
2033 Some user-configurable properties are internally represented as
2034 @emph{alists} (association lists), which store pairs of
2035 @emph{keys} and @emph{values}. The structure of an alist is:
2038 '((@var{key1} . @var{value1})
2039 (@var{key2} . @var{value2})
2040 (@var{key3} . @var{value3})
2044 If an alist is a grob property or @code{\paper} variable, its keys
2045 can be modified individually without affecting other keys.
2047 For example, to reduce the space between adjacent staves in a
2048 staff-group, use the @code{staff-staff-spacing} property of the
2049 @code{StaffGrouper} grob. The property is an alist with four
2050 keys: @code{basic-distance}, @code{minimum-distance},
2051 @code{padding}, and @code{stretchability}. The standard settings
2052 for this property are listed in the @qq{Backend} section of the
2053 Internals Reference (see @rinternals{StaffGrouper}):
2056 '((basic-distance . 9)
2057 (minimum-distance . 7)
2059 (stretchability . 5))
2062 One way to bring the staves closer together is by reducing the
2063 value of the @code{basic-distance} key (@code{9}) to match the
2064 value of @code{minimum-distance} (@code{7}). To modify a single
2065 key individually, use a @emph{nested declaration}:
2067 @lilypond[quote,verbatim]
2068 % default space between staves
2070 \new Staff { \clef treble c''1 }
2071 \new Staff { \clef bass c1 }
2074 % reduced space between staves
2075 \new PianoStaff \with {
2076 % this is the nested declaration
2077 \override StaffGrouper #'staff-staff-spacing #'basic-distance = #7
2079 \new Staff { \clef treble c''1 }
2080 \new Staff { \clef bass c1 }
2084 Using a nested declaration will update the specified key (such as
2085 @code{basic-distance} in the above example) without altering any
2086 other keys already set for the same property.
2088 Now suppose we want the staves to be as close as possible without
2089 overlapping. The simplest way to do this is to set all four alist
2090 keys to zero. However, it is not necessary to enter four nested
2091 declarations, one for each key. Instead, the property can be
2092 completely re-defined with one declaration, as an alist:
2094 @lilypond[quote,verbatim]
2095 \new PianoStaff \with {
2096 \override StaffGrouper #'staff-staff-spacing =
2097 #'((basic-distance . 0)
2098 (minimum-distance . 0)
2100 (stretchability . 0))
2102 \new Staff { \clef treble c''1 }
2103 \new Staff { \clef bass c1 }
2107 Note that any keys not explicitly listed in the alist definition
2108 will be reset to their @emph{default-when-unset} values. In the
2109 case of @code{staff-staff-spacing}, any unset key-values would be
2110 reset to zero (except @code{stretchability}, which takes the value
2111 of @code{basic-distance} when unset). Thus the following two
2112 declarations are equivalent:
2115 \override StaffGrouper #'staff-staff-spacing =
2116 #'((basic-distance . 7))
2118 \override StaffGrouper #'staff-staff-spacing =
2119 #'((basic-distance . 7)
2120 (minimum-distance . 0)
2122 (stretchability . 7))
2125 One (possibly unintended) consequence of this is the removal of
2126 any standard settings that are set in an initialization file and
2127 loaded each time an input file is compiled. In the above example,
2128 the standard settings for @code{padding} and
2129 @code{minimum-distance} (defined in @file{scm/define-grobs.scm})
2130 are reset to their default-when-unset values (zero for both keys).
2131 Defining a property or variable as an alist (of any size) will
2132 always reset all unset key-values to their default-when-unset
2133 values. Unless this is the intended result, it is safer to update
2134 key-values individually with a nested declaration.
2136 @warning{Nested declarations will not work for context property
2137 alists (such as @code{beamExceptions}, @code{keySignature},
2138 @code{timeSignatureSettings}, etc.). These properties can only be
2139 modified by completely re-defining them as alists.}
2142 @node Useful concepts and properties
2143 @section Useful concepts and properties
2148 * Direction and placement::
2149 * Distances and measurements::
2150 * Staff symbol properties::
2152 * Visibility of objects::
2154 * Rotating objects::
2158 @subsection Input modes
2160 The way in which the notation contained within an input file is
2161 interpreted is determined by the current input mode.
2165 This is activated with the @code{\chordmode} command, and causes
2166 input to be interpreted with the syntax of chord notation, see
2167 @ref{Chord notation}. Chords are rendered as notes on a staff.
2169 Chord mode is also activated with the @code{\chords} command.
2170 This also creates a new @code{ChordNames} context and
2171 causes the following input to be interpreted with the syntax of
2172 chord notation and rendered as chord names in the @code{ChordNames}
2173 context, see @ref{Printing chord names}.
2177 This is activated with the @code{\drummode} command, and causes
2178 input to be interpreted with the syntax of drum notation, see
2179 @ref{Basic percussion notation}.
2181 Drum mode is also activated with the @code{\drums} command.
2182 This also creates a new @code{DrumStaff} context and causes the
2183 following input to be interpreted with the syntax of drum notation
2184 and rendered as drum symbols on a drum staff, see @ref{Basic
2185 percussion notation}.
2187 @strong{Figure mode}
2189 This is activated with the @code{\figuremode} command, and causes
2190 input to be interpreted with the syntax of figured bass, see
2191 @ref{Entering figured bass}.
2193 Figure mode is also activated with the @code{\figures} command.
2194 This also creates a new @code{FiguredBass} context and causes the
2195 following input to be interpreted with the figured bass syntax
2196 and rendered as figured bass symbols in the @code{FiguredBass}
2197 context, see @ref{Introduction to figured bass}.
2199 @strong{Fret and tab modes}
2201 There are no special input modes for entering fret and tab symbols.
2203 To create tab diagrams, enter notes or chords in note mode and
2204 render them in a @code{TabStaff} context, see
2205 @ref{Default tablatures}.
2207 To create fret diagrams above a staff, you have two choices.
2208 You can either use the @code{FretBoards} context (see
2209 @ref{Automatic fret diagrams} or you can enter them as a markup
2210 above the notes using the @code{\fret-diagram} command (see
2211 @ref{Fret diagram markups}).
2213 @strong{Lyrics mode}
2215 This is activated with the @code{\lyricmode} command, and causes
2216 input to be interpreted as lyric syllables with optional durations
2217 and associated lyric modifiers, see @ref{Vocal music}.
2219 Lyric mode is also activated with the @code{\addlyrics} command.
2220 This also creates a new @code{Lyrics} context and an implicit
2221 @code{\lyricsto} command which associates the following lyrics
2222 with the preceding music.
2224 @strong{Markup mode}
2226 This is activated with the @code{\markup} command, and causes
2227 input to be interpreted with the syntax of markup, see
2228 @ref{Text markup commands}.
2230 @c silly work-around for texinfo broken-ness
2231 @c (@strong{Note...} causes a spurious cross-reference in Info)
2234 This is the default mode or it may be activated with the
2235 @code{\notemode} command. Input is interpreted as pitches,
2236 durations, markup, etc and typeset as musical notation on a staff.
2238 It is not normally necessary to specify note mode explicitly, but
2239 it may be useful to do so in certain situations, for example if you
2240 are in lyric mode, chord mode or any other mode and want to insert
2241 something that only can be done with note mode syntax.
2243 For example, to indicate dynamic markings for the verses of a
2244 choral pieces it is necessary to enter note mode to interpret
2247 @lilypond[verbatim,relative=2,quote]
2250 \notemode{\set stanza = \markup{ \dynamic f 1. } }
2254 \notemode{\set stanza = \markup{ \dynamic p 2. } }
2261 @node Direction and placement
2262 @subsection Direction and placement
2264 In typesetting music the direction and placement of many items is
2265 a matter of choice. For example, the stems of notes can
2266 be directed up or down; lyrics, dynamics, and other expressive
2267 marks may be placed above or below the staff; text may be aligned
2268 left, right or center; etc. Most of these choices may be left to
2269 be determined automatically by LilyPond, but in some cases it may
2270 be desirable to force a particular direction or placement.
2272 @strong{Articulation direction indicators}
2274 By default some directions are always up or always down (e.g.
2275 dynamics or fermata), while other things can alternate between
2276 up or down based on the stem direction (like slurs or accents).
2278 @c TODO Add table showing these
2280 The default action may be overridden by prefixing the articulation
2281 by a @emph{direction indicator}. Three direction indicators are
2282 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
2283 and @code{-} (meaning @qq{use default direction}). The direction
2284 indicator can usually be omitted, in which case @code{-} is assumed,
2285 but a direction indicator is @strong{always} required before
2288 @item @code{\tweak} commands
2289 @item @code{\markup} commands
2290 @item @code{\tag} commands
2291 @item string markups, e.g. -"string"
2292 @item fingering instructions, e.g. @w{@code{-1}}
2293 @item articulation shortcuts, e.g. @w{@code{-.}}, @w{@code{->}}, @w{@code{--}}
2296 Direction indicators affect only the next note:
2298 @lilypond[verbatim,quote,relative=2]
2305 @strong{The direction property}
2307 The position or direction of many layout objects is controlled by the
2308 @code{direction} property.
2310 The value of the @code{direction} property may be set to @code{1},
2311 meaning @qq{up} or @qq{above}, or to @w{@code{-1}}, meaning @qq{down} or
2312 @qq{below}. The symbols @code{UP} and @code{DOWN} may be used instead
2313 of @code{1} and @w{@code{-1}} respectively. The default direction may
2314 be specified by setting @code{direction} to @code{0} or @code{CENTER}.
2315 Alternatively, in many cases predefined commands exist to specify the
2316 direction. These are of the form
2319 @code{\xxxUp}, @code{\xxxDown} or @code{\xxxNeutral}
2323 where @code{\xxxNeutral} means @qq{use the default} direction.
2324 See @rlearning{Within-staff objects}.
2326 In a few cases, arpeggio for example, the value of the @code{direction}
2327 property can specify whether the object is to be placed to the right or
2328 left of the parent. In this case @w{@code{-1}} or @code{LEFT} means
2329 @qq{to the left} and @code{1} or @code{RIGHT} means @qq{to the right}.
2330 @code{0} or @code{CENTER} means @qq{use the default} direction.
2333 These all have side-axis set to #X
2334 AmbitusAccidental - direction has no effect
2336 StanzaNumber - not tried
2337 TrillPitchAccidental - not tried
2338 TrillPitchGroup - not tried
2341 These indications affect all notes until they are canceled.
2343 @lilypond[verbatim,quote,relative=2]
2352 In polyphonic music, it is generally better to specify an explicit
2353 @code{voice} than change an object's direction. For more information.
2354 See @ref{Multiple voices}.
2358 @rlearning{Within-staff objects}.
2361 @ref{Multiple voices}.
2364 @node Distances and measurements
2365 @subsection Distances and measurements
2367 @cindex distances, absolute
2368 @cindex distances, scaled
2375 Distances in LilyPond are of two types: absolute and scaled.
2377 Absolute distances are used for specifying margins, indents, and
2378 other page layout details, and are by default specified in
2379 millimeters. Distances may be specified in other units by
2380 following the quantity by @code{\mm}, @code{\cm},
2381 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27 of
2382 an inch). Page layout distances can also be specified in scalable
2383 units (see the following paragraph) by appending
2384 @code{\staff-space} to the quantity. Page layout is described in
2385 detail in @ref{Page layout}.
2387 Scaled distances are always specified in units of the staff-space
2388 or, rarely, the half staff-space. The staff-space is the distance
2389 between two adjacent staff lines. The default value can be changed
2390 globally by setting the global staff size, or it can be overridden
2391 locally by changing the @code{staff-space} property of
2392 @code{StaffSymbol}. Scaled distances automatically scale with any
2393 change to the either the global staff size or the
2394 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2395 automatically only with changes to the global staff size.
2396 The global staff size thus enables the overall size of a rendered
2397 score to be easily varied. For the methods of setting the global
2398 staff size see @ref{Setting the staff size}.
2402 If just a section of a score needs to be rendered to a different
2403 scale, for example an ossia section or a footnote, the global staff
2404 size cannot simply be changed as this would affect the entire score.
2405 In such cases the change in size is made by overriding both the
2406 @code{staff-space} property of @code{StaffSymbol} and the size of
2407 the fonts. A Scheme function, @code{magstep}, is available to
2408 convert from a font size change to the equivalent change in
2409 @code{staff-space}. For an explanation and an example of its use,
2410 see @rlearning{Length and thickness of objects}.
2414 @rlearning{Length and thickness of objects}.
2418 @ref{Setting the staff size}.
2421 @node Staff symbol properties
2422 @subsection Staff symbol properties
2424 @cindex adjusting staff symbol
2425 @cindex drawing staff symbol
2426 @cindex staff symbol, setting of
2428 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2429 @c Need to think of uses for these properties. Eg 'line-positions
2430 @c is used in a snippet to thicken centre line.
2431 @c If retained, add @ref to here in 1.6.2 -td
2433 The vertical position of staff lines and the number of staff lines
2434 can be defined at the same time. As the following example shows,
2435 note positions are not influenced by the staff line positions.
2437 @warning{The @code{'line-positions} property overrides the
2438 @code{'line-count} property. The number of staff lines is
2439 implicitly defined by the number of elements in the list of values
2440 for @code{'line-positions}.}
2442 @lilypond[verbatim,quote,relative=1]
2444 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
2449 The width of a staff can be modified. The units are staff
2450 spaces. The spacing of objects inside the staff is not affected by
2453 @lilypond[verbatim,quote,relative=1]
2455 \override StaffSymbol #'width = #23
2462 @subsection Spanners
2464 Many objects of musical notation extend over several notes or even
2465 several bars. Examples are slurs, beams, tuplet brackets, volta
2466 repeat brackets, crescendi, trills, and glissandi. Such objects
2467 are collectively called @qq{spanners}, and have special properties to control
2468 their appearance and behaviour. Some of these properties are common
2469 to all spanners; others are restricted to a sub-set of the spanners.
2471 All spanners support the @code{spanner-interface}. A few, essentially
2472 those that draw a straight line between the two objects, support in
2473 addition the @code{line-spanner-interface}.
2475 @unnumberedsubsubsec Using the @code{spanner-interface}
2477 This interface provides two properties that apply to several spanners.
2479 @strong{@i{The @code{minimum-length} property}}
2481 The minimum length of the spanner is specified by the
2482 @code{minimum-length} property. Increasing this usually has the
2483 necessary effect of increasing the spacing of the notes between the
2484 two end points. However, this override has no effect on
2485 many spanners, as their length is determined by other considerations.
2486 A few examples where it is effective are shown below.
2496 Works as long as callback is made:
2500 Works not at all for:
2509 @lilypond[verbatim,quote,relative=2]
2512 % increase the length of the tie
2513 -\tweak #'minimum-length #5
2517 @lilypond[verbatim,quote,relative=2]
2519 \compressFullBarRests
2521 % increase the length of the rest bar
2522 \once \override MultiMeasureRest #'minimum-length = #20
2527 @lilypond[verbatim,quote,relative=2]
2529 % increase the length of the hairpin
2530 \override Hairpin #'minimum-length = #20
2534 This override can also be used to increase the length of slurs and
2537 @lilypond[verbatim,quote,relative=2]
2540 -\tweak #'minimum-length #5
2545 -\tweak #'minimum-length #5
2549 For some layout objects, the @code{minimum-length} property becomes
2550 effective only if the @code{set-spacing-rods} procedure is called
2551 explicitly. To do this, the @code{springs-and-rods} property should
2552 be set to @code{ly:spanner::set-spacing-rods}. For example,
2553 the minimum length of a glissando has no effect unless the
2554 @code{springs-and-rods} property is set:
2556 @lilypond[verbatim,quote,relative=1]
2560 % not effective alone
2561 \once \override Glissando #'minimum-length = #20
2564 % effective only when both overrides are present
2565 \once \override Glissando #'minimum-length = #20
2566 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2570 The same is true of the @code{Beam} object:
2572 @lilypond[verbatim,quote,relative=1]
2573 % not effective alone
2574 \once \override Beam #'minimum-length = #20
2577 % effective only when both overrides are present
2578 \once \override Beam #'minimum-length = #20
2579 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2583 @strong{@i{The @code{to-barline} property}}
2585 The second useful property of the @code{spanner-interface} is
2586 @code{to-barline}. By default this is true, causing hairpins and
2587 other spanners which are terminated on the first note of a measure to
2588 end instead on the immediately preceding bar line. If set to false,
2589 the spanner will extend beyond the bar line and end on the note
2592 @lilypond[verbatim,quote,relative=2]
2593 a \< a a a a \! a a a \break
2594 \override Hairpin #'to-barline = ##f
2595 a \< a a a a \! a a a
2598 This property is not effective for all spanners. For example,
2599 setting it to @code{#t} has no effect on slurs or phrasing slurs
2600 or on other spanners for which terminating on the bar line would
2603 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2605 Objects which support the @code{line-spanner-interface} include
2608 @item @code{DynamicTextSpanner}
2609 @item @code{Glissando}
2610 @item @code{TextSpanner}
2611 @item @code{TrillSpanner}
2612 @item @code{VoiceFollower}
2615 The routine responsible for drawing the stencils for these spanners is
2616 @code{ly:line-interface::print}. This routine determines the
2617 exact location of the two end points and draws a line
2618 between them, in the style requested. The locations of the two
2619 end points of the spanner are computed on-the-fly, but it is
2620 possible to override their Y-coordinates. The
2621 properties which need to be specified are nested
2622 two levels down within the property hierarchy, but the syntax of
2623 the @code{\override} command is quite simple:
2625 @lilypond[relative=2,quote,verbatim]
2627 \once \override Glissando #'(bound-details left Y) = #3
2628 \once \override Glissando #'(bound-details right Y) = #-2
2632 The units for the @code{Y} property are @code{staff-space}s,
2633 with the center line of the staff being the zero point.
2634 For the glissando, this is the value for @code{Y} at the
2635 X-coordinate corresponding to the center point of each note head,
2636 if the line is imagined to be extended to there.
2638 If @code{Y} is not set, the value is computed from the vertical
2639 position of the corresponding attachment point of the spanner.
2641 In case of a line break, the values for the end points are
2642 specified by the @code{left-broken} and @code{right-broken}
2643 sub-lists of @code{bound-details}. For example:
2645 @lilypond[relative=2,ragged-right,verbatim,quote]
2646 \override Glissando #'breakable = ##t
2647 \override Glissando #'(bound-details right-broken Y) = #-3
2648 c1 \glissando \break
2653 A number of further properties of the @code{left} and
2654 @code{right} sub-lists of the @code{bound-details} property
2655 may be modified in the same way as @code{Y}:
2659 This sets the Y-coordinate of the end point, in @code{staff-space}s
2660 offset from the staff center line. By default, it is the center of
2661 the bound object, so a glissando points to the vertical center of
2664 For horizontal spanners, such as text spanners and trill spanners,
2665 it is hardcoded to 0.
2668 This determines where the line starts and ends in the X-direction,
2669 relative to the bound object. So, a value of @w{@code{-1}} (or
2670 @code{LEFT}) makes the line start/end at the left side of the note
2671 head it is attached to.
2674 This is the absolute X-coordinate of the end point. It is usually
2675 computed on the fly, and overriding it has little useful effect.
2678 Line spanners may have symbols at the beginning or end, which is
2679 contained in this sub-property. This is for internal use; it is
2680 recommended that @code{text} be used instead.
2683 This is a markup that is evaluated to yield the stencil. It is used
2684 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2686 @lilypond[quote,ragged-right,relative=2,verbatim]
2687 \override TextSpanner #'(bound-details left text)
2688 = \markup { \small \bold Slower }
2689 c2\startTextSpan b c a\stopTextSpan
2692 @item stencil-align-dir-y
2693 @item stencil-offset
2694 Without setting one of these, the stencil is simply put at the
2695 end-point, centered on the line, as defined by the @code{X} and
2696 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2697 or @code{stencil-offset} will move the symbol at the edge vertically
2698 relative to the end point of the line:
2700 @lilypond[relative=1,quote,verbatim]
2701 \override TextSpanner
2702 #'(bound-details left stencil-align-dir-y) = #-2
2703 \override TextSpanner
2704 #'(bound-details right stencil-align-dir-y) = #UP
2706 \override TextSpanner
2707 #'(bound-details left text) = #"ggg"
2708 \override TextSpanner
2709 #'(bound-details right text) = #"hhh"
2710 c4^\startTextSpan c c c \stopTextSpan
2713 Note that negative values move the text @emph{up}, contrary to the
2714 effect that might be expected, as a value of @w{@code{-1}} or
2715 @code{DOWN} means align the @emph{bottom} edge of the text with
2716 the spanner line. A value of @code{1} or @code{UP} aligns
2717 the top edge of the text with the spanner line.
2720 Setting this sub-property to @code{#t} produces an arrowhead at the
2724 This sub-property controls the space between the specified
2725 end point of the line and the actual end. Without padding, a
2726 glissando would start and end in the center of each note head.
2730 The music function @code{\endSpanners} terminates the spanner
2731 which starts on the immediately following note prematurely. It
2732 is terminated after exactly one note, or at the following bar line
2733 if @code{to-barline} is true and a bar line occurs before the next
2736 @lilypond[verbatim,quote,ragged-right,relative=2]
2738 c2 \startTextSpan c2 c2
2743 When using @code{\endSpanners} it is not necessary to close
2744 \startTextSpan with \stopTextSpan, nor is it necessary to close
2745 hairpins with @code{\!}.
2748 Internals Reference:
2749 @rinternals{TextSpanner},
2750 @rinternals{Glissando},
2751 @rinternals{VoiceFollower},
2752 @rinternals{TrillSpanner},
2753 @rinternals{line-spanner-interface}.
2756 @node Visibility of objects
2757 @subsection Visibility of objects
2759 @cindex objects, visibility of
2760 @cindex grobs, visibility of
2761 @cindex visibility of objects
2763 There are four main ways in which the visibility of layout objects
2764 can be controlled: their stencil can be removed, they can be made
2765 transparent, they can be colored white, or their
2766 @code{break-visibility} property can be overridden. The first
2767 three apply to all layout objects; the last to just a few -- the
2768 @emph{breakable} objects. The Learning Manual introduces these
2769 four techniques, see @rlearning{Visibility and color of objects}.
2771 There are also a few other techniques which are specific to
2772 certain layout objects. These are covered under Special
2776 * Removing the stencil::
2777 * Making objects transparent::
2778 * Painting objects white::
2779 * Using break-visibility::
2780 * Special considerations::
2784 @node Removing the stencil
2785 @unnumberedsubsubsec Removing the stencil
2787 @cindex stencil, removing
2789 Every layout object has a stencil property. By default this is set
2790 to the specific function which draws that object. If this property
2791 is overridden to @code{#f} no function will be called and the object
2792 will not be drawn. The default action can be recovered with
2795 @lilypond[quote,verbatim,relative=1]
2797 \override Score.BarLine #'stencil = ##f
2799 \revert Score.BarLine #'stencil
2803 @node Making objects transparent
2804 @unnumberedsubsubsec Making objects transparent
2806 @cindex transparent, making objects
2808 Every layout object has a transparent property which by default is
2809 set to @code{#f}. If set to @code{#t} the object still occupies
2810 space but is made invisible.
2812 @lilypond[quote,verbatim,relative=2]
2814 \once \override NoteHead #'transparent = ##t
2818 @node Painting objects white
2819 @unnumberedsubsubsec Painting objects white
2821 @cindex objects, coloring
2822 @cindex coloring objects
2824 @cindex printing order
2825 @cindex overwriting objects
2826 @cindex objects, overwriting
2827 @cindex grobs, overwriting
2829 Every layout object has a color property which by default is set
2830 to @code{black}. If this is overridden to @code{white} the object
2831 will be indistinguishable from the white background. However,
2832 if the object crosses other objects the color of the crossing
2833 points will be determined by the order in which they are drawn,
2834 and this may leave a ghostly image of the white object, as shown
2837 @lilypond[quote,verbatim,relative=2]
2838 \override Staff.Clef #'color = #white
2842 This may be avoided by changing the order of printing the objects.
2843 All layout objects have a @code{layer} property which should be set
2844 to an integer. Objects with the lowest value of @code{layer} are
2845 drawn first, then objects with progressively higher values are drawn,
2846 so objects with higher values overwrite objects with lower values.
2847 By default most objects are assigned a @code{layer} value of
2848 @code{1}, although a few objects, including @code{StaffSymbol} and
2849 @code{BarLine}, are assigned a value of @code{0}. The order of
2850 printing objects with the same value of @code{layer} is indeterminate.
2852 In the example above the white clef, with a default @code{layer}
2853 value of @code{1}, is drawn after the staff lines (default
2854 @code{layer} value @code{0}), so overwriting them. To change this,
2855 the @code{Clef} object must be given in a lower value of
2856 @code{layer}, say @w{@code{-1}}, so that it is drawn earlier:
2858 @lilypond[quote,verbatim,relative=2]
2859 \override Staff.Clef #'color = #white
2860 \override Staff.Clef #'layer = #-1
2864 @node Using break-visibility
2865 @unnumberedsubsubsec Using break-visibility
2867 @c TODO Add making other objects breakable
2869 @cindex break-visibility
2871 Most layout objects are printed only once, but some like
2872 bar lines, clefs, time signatures and key signatures, may need
2873 to be printed twice when a line break occurs -- once at the end
2874 of the line and again at the start of the next line. Such
2875 objects are called @emph{breakable}, and have a property, the
2876 @code{break-visibility} property to control their visibility
2877 at the three positions in which they may appear -- at the
2878 start of a line, within a line if they are changed, and at the
2879 end of a line if a change takes place there.
2881 For example, the time signature
2882 by default will be printed at the start of the first line, but
2883 nowhere else unless it changes, when it will be printed at the
2884 point at which the change occurs. If this change occurs at the
2885 end of a line the new time signature will be printed at the start
2886 of the next line and a cautionary time signature will be printed
2887 at the end of the previous line as well.
2889 This behaviour is controlled by the @code{break-visibility}
2890 property, which is explained in
2891 @c Leave this ref on a newline - formats incorrectly otherwise -td
2892 @rlearning{Visibility and color of objects}. This property takes
2893 a vector of three booleans which, in order, determine whether the
2894 object is printed at the end of, within the body of, or at the
2895 beginning of a line. Or to be more precise, before a line break,
2896 where there is no line break, or after a line break.
2898 Alternatively, these eight combinations may be specified
2899 by pre-defined functions, defined in @file{scm/output-lib.scm},
2900 where the last three columns indicate whether the layout objects
2901 will be visible in the positions shown at the head of the columns:
2903 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2904 @headitem Function @tab Vector @tab Before @tab At no @tab After
2905 @headitem form @tab form @tab break @tab break @tab break
2907 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2908 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2909 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2910 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2911 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2912 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2913 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2914 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2917 The default settings of @code{break-visibility} depend on the
2918 layout object. The following table shows all the layout objects
2919 of interest which are affected by @code{break-visibility} and the
2920 default setting of this property:
2922 @multitable @columnfractions .3 .3 .4
2924 @headitem Layout object @tab Usual context @tab Default setting
2926 @c omit Ambitus as it appears not to be affected by break-visibility -td
2927 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2928 @item @code{BarLine} @tab @code{Score} @tab calculated
2929 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2930 @c omit the following item until it can be explained -td
2931 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2932 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2933 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2934 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2935 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2936 @c omit KeyCancellation until it can be explained -td
2937 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2938 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2939 @c omit LeftEdge until it can be explained -td
2940 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2941 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2942 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2943 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2947 The example below shows the use of the vector form to control the
2948 visibility of bar lines:
2950 @lilypond[quote,verbatim,relative=1,ragged-right]
2953 % Remove bar line at the end of the current line
2954 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2960 Although all three components of the vector used to override
2961 @code{break-visibility} must be present, not all of them are
2962 effective with every layout object, and some combinations may
2963 even give errors. The following limitations apply:
2966 @item Bar lines cannot be printed at start of line.
2967 @item A bar number cannot be printed at the start of the first
2968 line unless it is set to be different from 1.
2969 @item Clef -- see below
2970 @item Double percent repeats are either all printed or all
2971 suppressed. Use begin-of line-invisible to print and
2972 all-invisible to suppress.
2973 @item Key signature -- see below
2974 @item OctavateEight -- see below
2977 @node Special considerations
2978 @unnumberedsubsubsec Special considerations
2980 @strong{@emph{Visibility following explicit changes}}
2982 @cindex key signature, visibility following explicit change
2983 @cindex explicitKeySignatureVisibility
2984 @cindex clef, visibility following explicit change
2985 @cindex explicitClefVisibility
2987 The @code{break-visibility} property controls the visibility of
2988 key signatures and changes of clef only at the start of lines,
2989 i.e. after a break. It has no effect on the visibility of the
2990 key signature or clef following an explicit key change or an
2991 explicit clef change within or at the end of a line. In the
2992 following example the key signature following the explicit change
2993 to B-flat major is still visible, even though @code{all-invisible}
2996 @lilypond[quote,verbatim,relative=1,ragged-right]
2999 % Try to remove all key signatures
3000 \override Staff.KeySignature #'break-visibility = #all-invisible
3008 The visibility of such explicit key signature and clef changes is
3009 controlled by the @code{explicitKeySignatureVisibility} and
3010 @code{explicitClefVisibility} properties. These are the equivalent
3011 of the @code{break-visibility} property and both take a vector of
3012 three booleans or the predefined functions listed above, exactly like
3013 @code{break-visibility}. Both are properties of the Staff context,
3014 not the layout objects themselves, and so they are set using the
3015 @code{\set} command. Both are set by default to @code{all-visible}.
3016 These properties control only the visibility of key signatures and
3017 clefs resulting from explicit changes and do not affect key
3018 signatures and clefs at the beginning of lines;
3019 @code{break-visibility} must still be overridden in the appropriate
3020 object to remove these.
3022 @lilypond[quote,verbatim,relative=1,ragged-right]
3025 \set Staff.explicitKeySignatureVisibility = #all-invisible
3026 \override Staff.KeySignature #'break-visibility = #all-invisible
3033 @strong{@emph{Visibility of cautionary accidentals}}
3035 To remove the cautionary accidentals printed at an explicit key
3036 change, set the Staff context property @code{printKeyCancellation}
3039 @lilypond[quote,verbatim,relative=1,ragged-right]
3042 \set Staff.explicitKeySignatureVisibility = #all-invisible
3043 \set Staff.printKeyCancellation = ##f
3044 \override Staff.KeySignature #'break-visibility = #all-invisible
3051 With these overrides only the accidentals before the notes remain
3052 to indicate the change of key.
3054 @c TODO Add visibility of cautionary accidentals before notes
3056 @strong{@emph{Automatic bars}}
3058 @cindex automaticBars
3059 @cindex bar lines, suppressing
3061 As a special case, the printing of bar lines can also be turned off
3062 by setting the @code{automaticBars} property in the Score context.
3063 If set to @code{#f}, bar lines will not be printed automatically;
3064 they must be explicitly created with a @code{\bar} command. Unlike
3065 the @code{\cadenzaOn} predefined command, measures are still counted.
3066 Bar generation will resume according to that count if this property
3067 is later set to @code{#t}. When set to @code{#f}, line breaks can
3068 occur only at explicit @code{\bar} commands.
3072 @strong{@emph{Octavated clefs}}
3074 @cindex octavated clefs, visibility of
3075 @cindex visibility of octavated clefs
3076 @cindex clefs, visibility of octavation
3078 The small octavation symbol on octavated clefs is produced by the
3079 @code{OctavateEight} layout object. Its visibility is automatically
3080 inherited from the @code{Clef} object, so it is not necessary to apply
3081 any required @code{break-visibility} overrides to the @code{OctavateEight}
3082 layout objects to suppress octavation symbols for invisible clefs.
3084 For explicit clef changes, the @code{explicitClefVisibility}
3085 property controls both the clef symbol and any octavation symbol
3090 @rlearning{Visibility and color of objects}.
3094 @subsection Line styles
3096 Some performance indications, e.g., @i{rallentando} and
3097 @i{accelerando} and @i{trills} are written as text and are
3098 extended over many measures with lines, sometimes dotted or wavy.
3100 These all use the same routines as the glissando for drawing the
3101 texts and the lines, and tuning their behavior is therefore also
3102 done in the same way. It is done with a spanner, and the routine
3103 responsible for drawing the spanners is
3104 @code{ly:line-interface::print}. This routine determines the
3105 exact location of the two @i{span points} and draws a line
3106 between them, in the style requested.
3108 Here is an example showing the different line styles available,
3109 and how to tune them.
3111 @lilypond[relative=2,ragged-right,verbatim,quote]
3113 \once \override Glissando #'style = #'dashed-line
3115 \override Glissando #'style = #'dotted-line
3117 \override Glissando #'style = #'zigzag
3119 \override Glissando #'style = #'trill
3123 The locations of the end-points of the spanner are computed
3124 on-the-fly for every graphic object, but it is possible to
3128 @lilypond[relative=2,ragged-right,verbatim,quote]
3130 \once \override Glissando #'(bound-details right Y) = #-2
3134 The value for @code{Y} is set to @w{@code{-2}} for the right end
3135 point. The left side may be similarly adjusted by specifying
3136 @code{left} instead of @code{right}.
3138 If @code{Y} is not set, the value is computed from the vertical
3139 position of the left and right attachment points of the spanner.
3141 Other adjustments of spanners are possible, for details, see
3144 @node Rotating objects
3145 @subsection Rotating objects
3147 Both layout objects and elements of markup text can be rotated by
3148 any angle about any point, but the method of doing so differs.
3151 * Rotating layout objects::
3155 @node Rotating layout objects
3156 @unnumberedsubsubsec Rotating layout objects
3158 @cindex rotating objects
3159 @cindex objects, rotating
3161 All layout objects which support the @code{grob-interface} can be
3162 rotated by setting their @code{rotation} property. This takes a
3163 list of three items: the angle of rotation counter-clockwise,
3164 and the x and y coordinates of the point relative to the object's
3165 reference point about which the rotation is to be performed. The
3166 angle of rotation is specified in degrees and the coordinates in
3169 The angle of rotation and the coordinates of the rotation point must
3170 be determined by trial and error.
3172 @cindex hairpins, angled
3173 @cindex angled hairpins
3175 There are only a few situations where the rotation of layout
3176 objects is useful; the following example shows one situation where
3179 @lilypond[quote,verbatim,relative=1]
3181 \override Hairpin #'rotation = #'(20 -1 0)
3185 @node Rotating markup
3186 @unnumberedsubsubsec Rotating markup
3188 All markup text can be rotated to lie at any angle by prefixing it
3189 with the @code{\rotate} command. The command takes two arguments:
3190 the angle of rotation in degrees counter-clockwise and the text to
3191 be rotated. The extents of the text are not rotated: they take
3192 their values from the extremes of the x and y coordinates of the
3193 rotated text. In the following example the
3194 @code{outside-staff-priority} property for text is set to @code{#f}
3195 to disable the automatic collision avoidance, which would push some
3196 of the text too high.
3198 @lilypond[quote,verbatim,relative=1]
3199 \override TextScript #'outside-staff-priority = ##f
3200 g4^\markup { \rotate #30 "a G" }
3201 b^\markup { \rotate #30 "a B" }
3202 des^\markup { \rotate #30 "a D-Flat" }
3203 fis^\markup { \rotate #30 "an F-Sharp" }
3206 @node Advanced tweaks
3207 @section Advanced tweaks
3209 This section discusses various approaches to fine tuning the
3210 appearance of the printed score.
3213 * Aligning objects::
3214 * Vertical grouping of grobs::
3215 * Modifying stencils::
3216 * Modifying shapes::
3217 * Unpure-pure containers::
3222 @rlearning{Tweaking output},
3223 @rlearning{Other sources of information}.
3226 @ref{Explaining the Internals Reference},
3227 @ref{Modifying properties}.
3230 @rextend{Interfaces for programmers}.
3233 @file{scm/define-grobs.scm}.
3236 @rlsr{Tweaks and overrides}.
3238 Internals Reference:
3239 @rinternals{All layout objects}.
3242 @node Aligning objects
3243 @subsection Aligning objects
3245 Graphical objects which support the @code{self-alignment-interface}
3246 and/or the @code{side-position-interface} can be aligned to a previously
3247 placed object in a variety of ways. For a list of these objects, see
3248 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
3250 All graphical objects have a reference point, a horizontal extent and a
3251 vertical extent. The horizontal extent is a pair of numbers
3252 giving the displacements from the reference point of the left and
3253 right edges, displacements to the left being negative. The vertical
3254 extent is a pair of numbers giving the displacement from the reference
3255 point to the bottom and top edges, displacements down being negative.
3257 An object's position on a staff is given by the values of the
3258 @code{X-offset} and @code{Y-offset} properties. The value of
3259 @code{X-offset} gives the displacement from the X coordinate of
3260 the reference point of the parent object, and the value of
3261 @code{Y-offset} gives the displacement from the center line of the
3262 staff. The values of @code{X-offset} and @code{Y-offset} may
3263 be set directly or may be set to be calculated by procedures in order
3264 to achieve alignment with the parent object.
3266 @warning{Many objects have special positioning considerations which
3267 cause any setting of @code{X-offset} or @code{Y-offset} to be
3268 ignored or modified, even though the object supports the
3269 @code{self-alignment-interface}. Overriding the @code{X-offset}
3270 or @code{Y-offset} properties to a fixed value causes the respective
3271 @code{self-alignment} property to be disregarded.}
3273 For example, an accidental can be repositioned vertically by setting
3274 @code{Y-offset} but any changes to @code{X-offset} have no effect.
3276 Rehearsal marks may be aligned with breakable objects such as bar
3277 lines, clef symbols, time signature symbols and key signatures. There
3278 are special properties to be found in the @code{break-aligned-interface}
3279 for positioning rehearsal marks on such objects.
3283 @ref{Using the break-alignable-interface}.
3286 @rextend{Callback functions}.
3289 * Setting X-offset and Y-offset directly::
3290 * Using the side-position-interface::
3291 * Using the self-alignment-interface::
3292 * Using the break-alignable-interface::
3295 @node Setting X-offset and Y-offset directly
3296 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
3298 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
3299 properties of many objects. The following example shows three
3300 notes with the default fingering position and the positions with @code{X-offset}
3301 and @code{Y-offset} modified.
3303 @lilypond[verbatim,quote,relative=2]
3306 -\tweak #'X-offset #0
3307 -\tweak #'Y-offset #0
3310 -\tweak #'X-offset #-1
3311 -\tweak #'Y-offset #1
3317 @node Using the side-position-interface
3318 @unnumberedsubsubsec Using the @code{side-position-interface}
3320 An object which supports the @code{side-position-interface} can be
3321 placed next to its parent object so that
3322 the specified edges of the two objects touch. The object may be
3323 placed above, below, to the right or to the left of the parent.
3324 The parent cannot be specified; it is determined by the order of
3325 elements in the input stream. Most objects have the associated
3326 note head as their parent.
3328 The values of the @code{side-axis} and @code{direction} properties
3329 determine where the object is to be placed, as follows:
3331 @c TODO add an example of each to the table
3333 @multitable @columnfractions .3 .3 .3
3334 @headitem @code{side-axis} @tab @code{direction} @tab
3335 @headitem property @tab property @tab Placement
3337 @item @code{0} @tab @code{-1} @tab left
3338 @item @code{0} @tab @code{1} @tab right
3339 @item @code{1} @tab @code{-1} @tab below
3340 @item @code{1} @tab @code{1} @tab above
3344 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
3345 the procedure @code{ly:side-position-interface::x-aligned-side}.
3346 This procedure will return the correct value of @code{X-offset} to
3347 place the object to the left or right side of the parent according
3348 to value of @code{direction}.
3350 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3351 the procedure @code{ly:side-position-interface::y-aligned-side}.
3352 This procedure will return the correct value of @code{Y-offset} to
3353 place the object to the top or bottom of the parent according
3354 to value of @code{direction}.
3356 @c TODO Add examples
3358 @node Using the self-alignment-interface
3359 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3361 @emph{Self-aligning objects horizontally}
3363 The horizontal alignment of an object which supports the
3364 @code{self-alignment-interface} is controlled by the value of
3365 the @code{self-alignment-X} property, provided the object's
3366 @code{X-offset} property is set to
3367 @code{ly:self-alignment-interface::x-aligned-on-self}.
3368 @code{self-alignment-X} may be given any
3369 real value, in units of half the total X extent of the
3370 object. Negative values move the object to the right, positive
3371 to the left. A value of @code{0} centers the object on the
3372 reference point of its parent, a value of @w{@code{-1}} aligns the
3373 left edge of the object on the reference point of its parent,
3374 and a value of @code{1} aligns the right edge of the object on the
3375 reference point of its parent. The symbols @code{LEFT},
3376 @code{CENTER}, and @code{RIGHT} may be used instead of the values
3377 @w{@code{-1}}, @code{0}, and @code{1}, respectively.
3379 Normally the @code{\override} command would be used to modify the
3380 value of @code{self-alignment-X}, but the @code{\tweak} command
3381 can be used to separately align several annotations on a single
3384 @lilypond[quote,verbatim,relative=1]
3386 -\tweak #'self-alignment-X #-1
3388 -\tweak #'self-alignment-X #0
3390 -\tweak #'self-alignment-X #RIGHT
3392 -\tweak #'self-alignment-X #-2.5
3393 ^"aligned further to the right"
3396 @emph{Self-aligning objects vertically}
3398 Objects may be aligned vertically in an analogous way to aligning
3399 them horizontally if the @code{Y-offset} property is set to
3400 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3401 other mechanisms are often involved in vertical alignment: the
3402 value of @code{Y-offset} is just one variable taken into account.
3403 This may make adjusting the value of some objects tricky.
3404 The units are just half the vertical extent of the object, which
3405 is usually quite small, so quite large numbers may be required.
3406 A value of @w{@code{-1}} aligns the lower edge of the object with
3407 the reference point of the parent object, a value of @code{0}
3408 aligns the center of the object with the reference point of the
3409 parent, and a value of @code{1} aligns the top edge of the object
3410 with the reference point of the parent. The symbols @code{DOWN},
3411 @code{CENTER}, and @code{UP} may be substituted for @w{@code{-1}},
3412 @code{0}, and @code{1}, respectively.
3414 @emph{Self-aligning objects in both directions}
3416 By setting both @code{X-offset} and @code{Y-offset}, an object may
3417 be aligned in both directions simultaneously.
3419 The following example shows how to adjust a fingering mark so
3420 that it nestles close to the note head.
3422 @lilypond[quote,verbatim,relative=2]
3424 -\tweak #'self-alignment-X #0.5 % move horizontally left
3425 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
3426 -\tweak #'self-alignment-Y #-1 % move vertically up
3431 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3433 @c Cannot document as they do not seem to operate consistently on all objects -td
3434 @c TODO investigate further
3436 The @code{aligned-on-parent} procedures are used in the same way
3437 as the @code{aligned-on-self} procedures, they difference being
3438 that they permit an object to be aligned with the @emph{edges} of
3439 the parent rather than the parent's reference point. The following
3440 example shows the difference:
3444 @lilypond[verbatim,quote]
3450 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3452 @c Cannot document as they do not seem to operate consistently on all objects -td
3453 @c TODO investigate further
3457 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3459 @node Using the break-alignable-interface
3460 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3462 @cindex align to objects
3463 @cindex break-align-symbols
3465 Rehearsal marks and bar numbers may be aligned with notation
3466 objects other than bar lines. These objects include @code{ambitus},
3467 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3468 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3469 @code{time-signature}.
3471 By default, rehearsal marks and bar numbers will be horizontally
3472 centered above the object:
3474 @lilypond[verbatim,quote,relative=1]
3475 % The rehearsal mark will be centered above the Clef
3476 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
3481 % The rehearsal mark will be centered above the Time Signature
3482 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
3488 % The rehearsal mark will be centered above the Breath Mark
3489 \override Score.RehearsalMark #'break-align-symbols = #'(breathing-sign)
3498 A list of possible target alignment objects may be specified. If
3499 some of the objects are invisible at that point due to the setting
3500 of @code{break-visibility} or the explicit visibility settings for
3501 keys and clefs, the rehearsal mark or bar number is aligned to the
3502 first object in the list which is visible. If no objects in the
3503 list are visible the object is aligned to the bar line. If the bar
3504 line is invisible the object is aligned to the place where the bar
3507 @lilypond[verbatim,quote,relative=1]
3508 % The rehearsal mark will be centered above the Key Signature
3509 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3514 % The rehearsal mark will be centered above the Clef
3515 \set Staff.explicitKeySignatureVisibility = #all-invisible
3516 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3521 % The rehearsal mark will be centered above the Bar Line
3522 \set Staff.explicitKeySignatureVisibility = #all-invisible
3523 \set Staff.explicitClefVisibility = #all-invisible
3524 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3531 The alignment of the rehearsal mark relative to the notation object
3532 can be changed, as shown in the following example. In a score with
3533 multiple staves, this setting should be done for all the staves.
3535 @lilypond[verbatim,quote,relative=1]
3536 % The RehearsalMark will be centered above the Key Signature
3537 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3543 % The RehearsalMark will be aligned with the left edge of the Key Signature
3544 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3548 % The RehearsalMark will be aligned with the right edge of the Key Signature
3549 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3555 The rehearsal mark can also be offset to the right or left of the left
3556 edge by an arbitrary amount. The units are staff-spaces:
3558 @lilypond[verbatim,quote,relative=1]
3559 % The RehearsalMark will be aligned with the left edge of the Key Signature
3560 % and then shifted right by 3.5 staff-spaces
3561 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3562 \once \override Score.KeySignature #'break-align-anchor = #3.5
3566 % The RehearsalMark will be aligned with the left edge of the Key Signature
3567 % and then shifted left by 2 staff-spaces
3568 \once \override Score.KeySignature #'break-align-anchor = #-2
3575 @node Vertical grouping of grobs
3576 @subsection Vertical grouping of grobs
3578 @c TODO Expand this section
3580 The VerticalAlignment and VerticalAxisGroup grobs work together.
3581 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3582 etc. VerticalAlignment then vertically aligns the different grobs
3583 grouped together by VerticalAxisGroup. There is usually only one
3584 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3588 @node Modifying stencils
3589 @subsection Modifying stencils
3591 All layout objects have a @code{stencil} property which is part of
3592 the @code{grob-interface}. By default, this property is usually
3593 set to a function specific to the object that is tailor-made to
3594 render the symbol which represents it in the output. For example,
3595 the standard setting for the @code{stencil} property of the
3596 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3598 The standard symbol for any object can be replaced by modifying the
3599 @code{stencil} property to reference a different, specially-written,
3600 procedure. This requires a high level of knowledge of the internal
3601 workings of LilyPond, but there is an easier way which can often
3602 produce adequate results.
3604 This is to set the @code{stencil} property to the procedure which
3605 prints text -- @code{ly:text-interface::print} -- and to add a
3606 @code{text} property to the object which is set to contain the
3607 markup text which produces the required symbol. Due to the
3608 flexibility of markup, much can be achieved -- see in particular
3609 @ref{Graphic notation inside markup}.
3611 The following example demonstrates this by changing the note head
3612 symbol to a cross within a circle.
3614 @lilypond[verbatim,quote]
3616 \once \override NoteHead #'stencil = #ly:text-interface::print
3617 \once \override NoteHead #'text = \markup {
3619 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3620 \musicglyph #"noteheads.s2cross"
3628 Any of the glyphs in the feta Font can be supplied to the
3629 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3631 @c TODO Add inserting eps files or ref to later
3633 @c TODO Add inserting Postscript or ref to later
3637 @ref{Graphic notation inside markup},
3638 @ref{Formatting text},
3639 @ref{Text markup commands},
3640 @ref{The Feta font}.
3643 @node Modifying shapes
3644 @subsection Modifying shapes
3647 * Modifying ties and slurs::
3650 @node Modifying ties and slurs
3651 @unnumberedsubsubsec Modifying ties and slurs
3653 @cindex slurs, modifying
3654 @cindex ties, modifying
3655 @cindex Bézier curves, control points
3656 @cindex control points, Bézier curves
3658 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3659 curves. If the shape of the tie or slur which is calculated
3660 automatically is not optimum, the shape may be modified manually by
3661 explicitly specifying the four control points required to define
3662 a third-order Bézier curve.
3664 Third-order or cubic Bézier curves are defined by four control
3665 points. The first and fourth control points are precisely the
3666 starting and ending points of the curve. The intermediate two
3667 control points define the shape. Animations showing how the curve
3668 is drawn can be found on the web, but the following description
3669 may be helpful. The curve starts from the first control point
3670 heading directly towards the second, gradually bending over to
3671 head towards the third and continuing to bend over to head towards
3672 the fourth, arriving there travelling directly from the third
3673 control point. The curve is entirely contained in the
3674 quadrilateral defined by the four control points.
3676 Here is an example of a case where the tie is not optimum, and
3677 where @code{\tieDown} would not help.
3679 @lilypond[verbatim,quote,relative=1]
3683 { r4 <g c,> <g c,> <g c,> }
3687 One way of improving this tie is to manually modify its control
3690 The coordinates of the Bézier control points are specified in units
3691 of staff-spaces. The X@tie{}coordinate is relative to the reference
3692 point of the note to which the tie or slur is attached, and the
3693 Y@tie{}coordinate is relative to the staff center line. The
3694 coordinates are entered as a list of four pairs of decimal numbers
3695 (reals). One approach is to estimate the coordinates of the two
3696 end points, and then guess the two intermediate points. The optimum
3697 values are then found by trial and error.
3699 It is useful to remember that a symmetric curve requires symmetric
3700 control points, and that Bézier curves have the useful property that
3701 transformations of the curve such as translation, rotation and
3702 scaling can be achieved by applying the same transformation to the
3703 curve's control points.
3705 For the example above the following override gives a satisfactory
3706 tie. Note the placement -- it has to be immediately before the note
3707 to which the start of the tie (or slur) is attached.
3709 @lilypond[verbatim,quote,relative=1]
3713 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3717 { r4 <g c,> <g c,> <g c,> }
3722 It is not possible to modify shapes of ties or slurs by changing
3723 the @code{control-points} property if there are multiple ties or slurs
3724 at the same musical moment -- the @code{\tweak} command will also not
3725 work in this case. However, the @code{tie-configuration} property of
3726 @code{TieColumn} can be overridden to set start line and direction as
3730 Internals Reference:
3731 @rinternals{TieColumn}.
3733 @cindex Scheme, pure containers
3734 @cindex Scheme, unpure containers
3735 @cindex pure containers, Scheme
3736 @cindex unpure containers, Scheme
3737 @cindex horizontal spacing, overriding
3740 @node Unpure-pure containers
3741 @subsection Unpure-pure containers
3743 Unpure-pure containers are useful for overriding @emph{Y-axis} spacing
3744 calculations - specifically @code{Y-offset} and @code{Y-extent} - with a
3745 Scheme function instead of a literal (i.e. a number or pair).
3747 For certain grobs, the @code{Y-extent} is based on the @code{stencil}
3748 property, overriding the stencil property of one of these will
3749 require an additional @code{Y-extent} override with an unpure-pure
3750 container. When a function overrides a @code{Y-offset} and/or
3751 @code{Y-extent} it is assumed that this will trigger line breaking
3752 calculations too early during compilation. So the function is not
3753 evaluated at all (usually returning a value of @samp{0} or
3754 @samp{'(0 . 0)}) which can result in collisions. A @q{pure} function
3755 will not affect properties, objects or grob suicides and therefore will
3756 always have its Y-axis-related evaluated correctly.
3758 Currently, there are about thirty functions that are already considered
3759 @q{pure} and Unpure-pure containers are a way to set functions not on
3760 this list as @q{pure}. The @q{pure} function is evaluated @emph{before}
3761 any line-breaking and so the horizontal spacing can be adjusted
3762 @q{in time}. The @q{unpure} function is then evaluated @emph{after}
3765 @warning{As it is difficult to always know which functions are on this
3766 list we recommend that any @q{pure} functions you create do not use
3767 @code{Beam} or @code{VerticalAlignment} grobs.}
3769 An unpure-pure container is constructed as follows;
3771 @code{(ly:make-unpure-pure-container f0 f1)}
3773 where @code{f0} is a function taking @var{n} arguments (@var{n >= 1})
3774 and the first argument must always be the grob. This is the function
3775 that gives the actual result. @var{f1} is the function being labeled
3776 as @q{pure} that takes @var{n + 2} arguments. Again, the first argument
3777 must always still be the grob but the second and third are @q{start}
3778 and @q{end} arguments.
3780 @var{start} and @var{end} are, for all intents and purposes, dummy
3781 values that only matter for @code{Spanners} (i.e @code{Hairpin} or
3782 @code{Beam}), that can return different height estimations based on a
3783 starting and ending column.
3785 The rest are the other arguments to the first function (which
3786 may be none if @var{n = 1}).
3788 The results of the second function are used as an approximation of the
3789 value needed which is then used by the first function to get the real
3790 value which is then used for fine-tuning much later during the spacing
3793 @lilypond[verbatim,quote,ragged-right]
3794 #(define (square-line-circle-space grob)
3795 (let* ((pitch (ly:event-property (ly:grob-property grob 'cause) 'pitch))
3796 (notename (ly:pitch-notename pitch)))
3797 (if (= 0 (modulo notename 2))
3798 (make-circle-stencil 0.5 0.0 #t)
3799 (make-filled-box-stencil '(0 . 1.0)
3802 squareLineCircleSpace = {
3803 \override NoteHead #'stencil = #square-line-circle-space
3806 smartSquareLineCircleSpace = {
3807 \squareLineCircleSpace
3808 \override NoteHead #'Y-extent =
3809 #(ly:make-unpure-pure-container
3810 ly:grob::stencil-height
3811 (lambda (grob start end) (ly:grob::stencil-height grob)))
3814 \new Voice \with { \remove "Stem_engraver" }
3816 \squareLineCircleSpace
3818 \smartSquareLineCircleSpace
3823 In the first measure, without the unpure-pure container, the spacing
3824 engine does not know the width of the note head and lets it collide with
3825 the accidentals. In the second measure, with unpure-pure containers,
3826 the spacing engine knows the width of the note heads and avoids the
3827 collision by lengthening the line accordingly.
3829 Usually for simple calculations nearly-identical functions for both the
3830 @q{unpure} and @q{pure} parts can be used, by only changing the number
3831 of arguments passed to, and the scope of, the function.
3833 @warning{If a function is labeled as @q{pure} and it turns out not to
3834 be, the results can be unexpected.}
3837 @node Using music functions
3838 @section Using music functions
3840 @c TODO -- add @seealso, etc. to these subsections
3842 Where tweaks need to be reused with different music expressions,
3843 it is often convenient to make the tweak part of a @emph{music
3844 function}. In this section, we discuss only @emph{substitution}
3845 functions, where the object is to substitute a variable into a
3846 piece of LilyPond input code. Other more complex functions are
3847 described in @rextend{Music functions}.
3850 * Substitution function syntax::
3851 * Substitution function examples::
3854 @node Substitution function syntax
3855 @subsection Substitution function syntax
3857 Making a function that substitutes a variable into LilyPond
3858 code is easy. The general form of these functions is
3862 #(define-music-function
3863 (parser location @var{arg1} @var{arg2} @dots{})
3864 (@var{type1?} @var{type2?} @dots{})
3866 @var{@dots{}music@dots{}}
3873 @multitable @columnfractions .33 .66
3874 @item @code{@var{argN}}
3875 @tab @var{n}th argument
3877 @item @code{@var{typeN?}}
3878 @tab a scheme @emph{type predicate} for which @code{@var{argN}}
3879 must return @code{#t}.
3881 @item @code{@var{@dots{}music@dots{}}}
3882 @tab normal LilyPond input, using @code{$} (in places where only
3883 Lilypond constructs are allowed) or @code{#} (to use it as a Scheme
3884 value or music function argument) to reference arguments
3888 The @code{parser} and @code{location} arguments are mandatory, and
3889 are used in some advanced situations as described in the
3890 @q{Extending} manual (see @rextend{Music functions}). For
3891 substitution functions, just be sure to include them.
3893 The list of type predicates is also required. Some of the most
3894 common type predicates used in music functions are:
3898 cheap-list? @emph{(use instead of }@q{list?}@emph{ for faster processing)}
3910 For a list of available type predicates, see
3911 @ref{Predefined type predicates}. User-defined type predicates
3916 @ref{Predefined type predicates}.
3919 @rextend{Music functions}.
3922 @file{lily/music-scheme.cc},
3924 @file{scm/lily.scm}.
3927 @node Substitution function examples
3928 @subsection Substitution function examples
3930 This section introduces some substitution function examples.
3931 These are not intended to be exhaustive, but rather to demonstrate
3932 some of the possibilities of simple substitution functions.
3934 In the first example, a function is defined that simplifies
3935 setting the padding of a TextScript:
3937 @lilypond[quote,verbatim,ragged-right]
3939 #(define-music-function
3940 (parser location padding)
3943 \once \override TextScript #'padding = #padding
3947 c4^"piu mosso" b a b
3949 c4^"piu mosso" d e f
3951 c4^"piu mosso" fis a g
3955 In addition to numbers, we can use music expressions such
3956 as notes for arguments to music functions:
3958 @lilypond[quote,verbatim,ragged-right]
3960 #(define-music-function
3961 (parser location note)
3964 \tweak NoteHead #'stencil #ly:text-interface::print
3965 \tweak NoteHead #'text
3966 \markup \musicglyph #"custodes.mensural.u0"
3967 \tweak Stem #'stencil ##f
3971 \relative c' { c4 d e f \custosNote g }
3974 Substitution functions with multiple arguments can be defined:
3976 @lilypond[quote,verbatim,ragged-right]
3978 #(define-music-function
3979 (parser location padding tempotext)
3982 \once \override Score.MetronomeMark #'padding = #padding
3983 \tempo \markup { \bold #tempotext }
3987 \tempo \markup { "Low tempo" }
3989 \tempoPadded #4.0 "High tempo"
3994 @c TODO: add appropriate @@ref's here.