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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::
62 * Creating and referencing contexts::
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
94 I knew it would... And leaving out some of them is perfectly fine
95 with me. I do think that a list like this, with the main contexts and a
96 brief description of what they do (perhaps also with a note about what
97 default behavior is associated with each of them, but this may be
98 unmanageable), should be there, and then we could simply list the
99 remaining ones without further explanation and with links to the IR.
102 @c TODO Improve layout, order and consistency of wording -td
104 @c TODO Add introduction which explains contexts in generality -td
106 @c TODO Describe propagation of property values -td
108 Contexts are arranged hierarchically:
111 * Output definitions - blueprints for contexts::
112 * Score - the master of all contexts::
113 * Top-level contexts - staff containers::
114 * Intermediate-level contexts - staves::
115 * Bottom-level contexts - voices::
118 @node Output definitions - blueprints for contexts
119 @unnumberedsubsubsec Output definitions - blueprints for contexts
121 This section explains the relevance of output definitions when
122 working with contexts. Examples for actual output definitions are
123 given later (see @ref{Changing all contexts of the same type}).
125 @cindex output definitions
127 While music written in a file may refer to context types and
128 names, contexts are created only when the music is actually being
129 interpreted. LilyPond interprets music under control of an
130 @q{output definition} and may do so for several different output
131 definitions, resulting in different output. The output definition
132 relevant for printing music is specified using @code{\layout}.
135 A much simpler output definition used for producing Midi output is
136 specified using @code{\midi}. Several other output definitions
137 are used by LilyPond internally, like when using the part combiner
138 (@ref{Automatic part combining}) or creating music quotes
139 (@ref{Quoting other voices}).
141 Output definitions define the relation between contexts as well as
142 their respective default settings. While most changes will
143 usually be made inside of a @code{\layout} block, Midi-related
144 settings will only have an effect when made within a @code{\midi}
147 @funindex autoBeaming
148 Some settings affect several outputs: for example, if
149 @code{autoBeaming} is turned off in some context, beams count as
150 melismata for the purpose of matching music to lyrics as described
151 in @ref{Automatic syllable durations}. This matching is done both
152 for printed output as well as for Midi. If changes made to
153 @code{autoBeaming} within a context definition of a @code{\layout}
154 block are not repeated in the corresponding @code{\midi} block,
155 lyrics and music will get out of sync in Midi.
159 @file{ly/engraver-init.ly}.
160 @file{ly/performer-init.ly}.
162 @node Score - the master of all contexts
163 @unnumberedsubsubsec Score - the master of all contexts
165 This is the top level notation context. No other context can
166 contain a Score context. By default the Score context handles
167 the administration of time signatures and makes sure that items
168 such as clefs, time signatures, and key-signatures are aligned
171 A Score context is instantiated implicitly when a
172 @code{\score @{@dots{}@}} block is processed.
174 @node Top-level contexts - staff containers
175 @unnumberedsubsubsec Top-level contexts - staff containers
177 @strong{@emph{StaffGroup}}
179 Groups staves while adding a bracket on the left side, grouping
180 the staves together. The bar lines of the contained staves are
181 connected vertically. @code{StaffGroup} only consists of a collection
182 of staves, with a bracket in front and spanning bar lines.
184 @strong{@emph{ChoirStaff}}
186 Identical to @code{StaffGroup} except that the bar lines of the
187 contained staves are not connected vertically.
189 @strong{@emph{GrandStaff}}
191 A group of staves, with a brace on the left side, grouping the
192 staves together. The bar lines of the contained staves are
193 connected vertically.
195 @strong{@emph{PianoStaff}}
197 Just like @code{GrandStaff}, but with support for instrument names
198 to the left of each system.
200 @node Intermediate-level contexts - staves
201 @unnumberedsubsubsec Intermediate-level contexts - staves
203 @strong{@emph{Staff}}
205 Handles clefs, bar lines, keys, accidentals. It can contain
206 @code{Voice} contexts.
208 @strong{@emph{RhythmicStaff}}
210 Like @code{Staff} but for printing rhythms. Pitches are ignored
211 when engraving; the notes are printed on one line. The MIDI
212 rendition retains pitches unchanged.
214 @strong{@emph{TabStaff}}
216 Context for generating tablature. By default lays the music
217 expression out as a guitar tablature, printed on six lines.
219 @strong{@emph{DrumStaff}}
221 Handles typesetting for percussion. Can contain @code{DrumVoice}.
223 @strong{@emph{VaticanaStaff}}
225 Same as @code{Staff}, except that it is designed for typesetting
226 a piece in gregorian style.
228 @strong{@emph{MensuralStaff}}
230 Same as @code{Staff}, except that it is designed for typesetting
231 a piece in mensural style.
233 @node Bottom-level contexts - voices
234 @unnumberedsubsubsec Bottom-level contexts - voices
236 Voice-level contexts initialise certain properties and start
237 appropriate engravers. A bottom-level context is one without
238 @code{defaultchild}. While it is possible to let it
239 accept/@/contain subcontexts, they can only be created and entered
242 @strong{@emph{Voice}}
244 Corresponds to a voice on a staff. This context handles the
245 conversion of dynamic signs, stems, beams, super- and sub-scripts,
246 slurs, ties, and rests. You have to instantiate this explicitly
247 if you require multiple voices on the same staff.
249 @strong{@emph{VaticanaVoice}}
251 Same as @code{Voice}, except that it is designed for typesetting
252 a piece in gregorian style.
254 @strong{@emph{MensuralVoice}}
256 Same as @code{Voice}, with modifications for typesetting a piece in
259 @strong{@emph{Lyrics}}
261 Corresponds to a voice with lyrics. Handles the printing of a
262 single line of lyrics.
264 @strong{@emph{DrumVoice}}
266 The voice context used in a percussion staff.
268 @strong{@emph{FiguredBass}}
270 The context in which @code{BassFigure} objects are created from
271 input entered in @code{\figuremode} mode.
273 @strong{@emph{TabVoice}}
275 The voice context used within a @code{TabStaff} context. Usually
276 left to be created implicitly.
278 @strong{@emph{CueVoice}}
280 A voice context used to render notes of a reduced size, intended
281 primarily for adding cue notes to a staff, see @ref{Formatting
282 cue notes}. Usually left to be created implicitly.
284 @strong{@emph{ChordNames}}
286 Typesets chord names.
291 Then the following, which I don't know what to do with:
293 * GregorianTranscriptionVoice
294 * GregorianTranscriptionStaff
297 Engraves fretboards from chords. Not easy... Not
299 There is now some documentation on FretBoards in the NR, under
300 instrument-specific notation -- cds.
305 Hard coded entry point for LilyPond. Cannot be tuned.
307 Silently discards all musical information given to this
312 @node Creating and referencing contexts
313 @subsection Creating and referencing contexts
318 @cindex referencing contexts
319 @cindex Contexts, creating and referencing
321 LilyPond will create lower-level contexts automatically if a music
322 expression is encountered before a suitable context exists, but this
323 is usually successful only for simple scores or music fragments like
324 the ones in the documentation. For more complex scores it is
325 advisable to specify all contexts explicitly with either the
326 @code{\new} or @code{\context} command. The syntax of
327 these two commands is very similar:
330 [\new | \context] @var{Context} [ = @var{name}] [@var{music-expression}]
334 where either @code{\new} or @code{\context} may be specified.
335 @var{Context} is the type of context which is to be created,
336 @var{name} is an optional name to be given to the particular context
337 being created and @var{music-expression} is a single music expression
338 that is to be interpreted by the engravers and performers in this
341 The @code{\new} prefix without a name is commonly used to create
342 scores with many staves:
344 @lilypond[quote,verbatim]
346 \new Staff \relative {
347 % leave the Voice context to be created implicitly
350 \new Staff \relative {
357 and to place several voices into one staff:
359 @lilypond[quote,verbatim]
361 \new Voice \relative {
365 \new Voice \relative {
373 @code{\new} should always be used to specify unnamed contexts.
375 The difference between @code{\new} and @code{\context} is in the
380 @code{\new} with or without a name will always create a fresh,
381 distinct, context, even if one with the same name already exists:
383 @lilypond[quote,verbatim]
385 \new Voice = "A" \relative {
389 \new Voice = "A" \relative {
397 @code{\context} with a name specified will create a distinct context
398 only if a context of the same type with the same name in the same
399 context hierarchy does not already exist. Otherwise it will be taken
400 as a reference to that previously created context, and its music
401 expression will be passed to that context for interpretation.
403 One application of named contexts is in separating the score layout
404 from the musical content. Either of these two forms is valid:
406 @lilypond[quote,verbatim]
420 \context Voice = "one" {
425 \context Voice = "two" {
434 @lilypond[quote,verbatim]
439 \context Voice = "one" {
442 \context Voice = "two" {
448 \context Voice = "one" {
453 \context Voice = "two" {
463 Alternatively, variables may be employed to similar effect. See
464 @rlearning{Organizing pieces with variables}.
467 @code{\context} with no name will match the first of any previously
468 created contexts of the same type in the same context heirarchy,
469 even one that has been given a name, and its music expression will be
470 passed to that context for interpretation. This form is rarely
471 useful. However, @code{\context} with no name and no music expression
472 is used to set the context in which a Scheme procedure specified with
473 @code{\applyContext} is executed:
476 \new Staff \relative @{
479 \applyContext #(lambda (ctx)
481 (display (ly:context-current-moment ctx)))
488 A context must be named if it is to be referenced later, for example
489 when lyrics are associated with music:
492 \new Voice = "tenor" @var{music}
494 \new Lyrics \lyricsto "tenor" @var{lyrics}
498 For details of associating lyrics with music see
499 @ref{Automatic syllable durations}.
501 The properties of all contexts of a particular type can be modified
502 in a @code{\layout} block (with a different syntax), see
503 @ref{Changing all contexts of the same type}. This construct also
504 provides a means of keeping layout instructions separate from the
505 musical content. If a single context is to be modified, a @code{\with}
506 block must be used, see @ref{Changing just one specific context}.
510 @rlearning{Organizing pieces with variables}.
513 @ref{Changing just one specific context},
514 @ref{Automatic syllable durations}.
517 @node Keeping contexts alive
518 @subsection Keeping contexts alive
520 @cindex contexts, keeping alive
521 @cindex contexts, lifetime
523 Contexts are usually terminated at the first musical moment in
524 which they have nothing to do. So @code{Voice} contexts die as
525 soon as they contain no events, @code{Staff} contexts die as soon
526 as all the @code{Voice} contexts within them contain no events, etc.
527 This can cause difficulties if earlier contexts which have died
528 have to be referenced, for example, when changing staves with
529 @code{\change} commands, associating lyrics with a voice with
530 @code{\lyricsto} commands, or when adding further musical events to
533 There is an exception to this general rule: inside of an
534 @code{@{@dots{}@}} construct (sequential music), the construct's
535 notion of the ``current context'' will descend whenever an element
536 of the sequence ends in a subcontext of the previous current
537 context. This avoids spurious creation of implicit contexts in a
538 number of situations but means that the first context descended
539 into will be kept alive until the end of the expression.
541 In contrast, the contexts of a @code{<<@dots{}>>} construct's
542 (simultaneous music) expression are not carried forth, so
543 enclosing a context creating command in an extra pair of
544 @code{<<@dots{}>>} will keep the context from persisting through
545 all of the enclosing @code{@{@dots{}@}} sequence.
547 Any context can be kept alive by ensuring it has something to do at
548 every musical moment. @code{Staff} contexts are kept alive by
549 ensuring one of their voices is kept alive. One way of doing this
550 is to add spacer rests to a voice in parallel with the real music.
551 These need to be added to every @code{Voice} context which needs to
552 be kept alive. If several voices are to be used sporadically it is
553 safest to keep them all alive rather than attempting to rely on the
554 exceptions mentioned above.
556 In the following example, both voice A and voice B are kept alive
557 in this way for the duration of the piece:
559 @lilypond[quote,verbatim]
560 musicA = \relative { d''4 d d d }
561 musicB = \relative { g'4 g g g }
564 \new Voice = "A" { s1*5 } % Keep Voice "A" alive for 5 bars
565 \new Voice = "B" { s1*5 } % Keep Voice "B" alive for 5 bars
570 \context Voice = "A" {
574 \context Voice = "B" {
578 \context Voice = "A" { \musicA }
579 \context Voice = "B" { \musicB }
580 \context Voice = "A" { \musicA }
591 @cindex lyrics, aligning with sporadic melody
593 The following example shows how a sporadic melody line with lyrics
594 might be written using this approach. In a real situation the
595 melody and accompaniment would consist of several different
598 @lilypond[quote,verbatim]
599 melody = \relative { a'4 a a a }
600 accompaniment = \relative { d'4 d d d }
601 words = \lyricmode { These words fol -- low the mel -- o -- dy }
604 \new Staff = "music" {
606 \new Voice = "melody" {
608 s1*4 % Keep Voice "melody" alive for 4 bars
611 \new Voice = "accompaniment" {
616 \context Voice = "melody" { \melody }
617 \context Voice = "accompaniment" { \accompaniment }
619 \context Voice = "accompaniment" { \accompaniment }
621 \context Voice = "melody" { \melody }
622 \context Voice = "accompaniment" { \accompaniment }
627 \new Lyrics \with { alignAboveContext = #"music" }
628 \lyricsto "melody" { \words }
633 An alternative way, which may be better in many circumstances, is
634 to keep the melody line alive by simply including spacer notes to
635 line it up correctly with the accompaniment:
637 @lilypond[quote,verbatim]
644 accompaniment = \relative {
650 words = \lyricmode { These words fol -- low the mel -- o -- dy }
654 \new Staff = "music" {
656 \new Voice = "melody" {
660 \new Voice = "accompaniment" {
666 \new Lyrics \with { alignAboveContext = #"music" }
667 \lyricsto "melody" { \words }
673 @node Modifying context plug-ins
674 @subsection Modifying context plug-ins
676 @c TODO Should this be Modifying engravers or Modifying contexts?
678 Notation contexts (like @code{Score} and @code{Staff}) not only store
679 properties, they also contain plug-ins called @q{engravers} that create
680 notation elements. For example, the @code{Voice} context contains a
681 @code{Note_heads_engraver} and the @code{Staff} context contains a
684 For a full a description of each plug-in, see
686 @rinternals{Engravers and Performers}.
689 Internals Reference @expansion{} Translation @expansion{} Engravers.
691 Every context described in
693 @rinternals{Contexts}
696 Internals Reference @expansion{} Translation @expansion{} Context.
698 lists the engravers used for that context.
701 It can be useful to shuffle around these plug-ins. This is done by
702 starting a new context with @code{\new} or @code{\context}, and
708 \new @var{context} \with @{
716 @emph{@dots{}music@dots{}}
721 where the @dots{} should be the name of an engraver. Here is a simple
722 example which removes @code{Time_signature_engraver} and
723 @code{Clef_engraver} from a @code{Staff} context,
725 @lilypond[quote,verbatim]
727 \new Staff \relative {
731 \remove "Time_signature_engraver"
732 \remove "Clef_engraver"
739 In the second staff there are no time signature or clef symbols. This
740 is a rather crude method of making objects disappear since it will affect
741 the entire staff. This method also influences the spacing, which may or
742 may not be desirable. More sophisticated methods of blanking objects
743 are shown in @rlearning{Visibility and color of objects}.
745 The next example shows a practical application. Bar lines and time
746 signatures are normally synchronized across the score. This is done
747 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
748 This plug-in keeps an administration of time signature, location
749 within the measure, etc. By moving these engraver from @code{Score} to
750 @code{Staff} context, we can have a score where each staff has its own
753 @cindex polymetric scores
754 @cindex time signature, multiple
756 @lilypond[quote,verbatim]
760 \consists "Timing_translator"
761 \consists "Default_bar_line_engraver"
768 \consists "Timing_translator"
769 \consists "Default_bar_line_engraver"
779 \remove "Timing_translator"
780 \remove "Default_bar_line_engraver"
788 The order in which the engravers are specified is the order in
789 which they are called to carry out their processing. Usually the
790 order in which the engravers are specified does not matter, but in
791 a few special cases the order is important, for example where one
792 engraver writes a property and another reads it, or where one
793 engraver creates a grob and another must process it.
795 The following orderings are important:
799 the @code{Bar_engraver} must normally be first,
802 the @code{New_fingering_engraver} must come before the
803 @code{Script_column_engraver},
806 the @code{Timing_translator} must come before the
807 @code{Bar_number_engraver}.
813 @file{ly/engraver-init.ly}.
816 @node Changing context default settings
817 @subsection Changing context default settings
819 @cindex default context properties, changing
820 @cindex context properties, changing defaults
822 Context and grob properties can be changed with @code{\set}
823 and @code{\override} commands, as described in
824 @ref{Modifying properties}. These commands create music events,
825 making the changes take effect at the point in time the music
828 In contrast, this section explains how to change the @emph{default}
829 values of context and grob properties at the time the context is
830 created. There are two ways of doing this. One modifies the default
831 values in all contexts of a particular type, the other modifies the
832 default values in just one particular instance of a context.
835 * Changing all contexts of the same type::
836 * Changing just one specific context::
837 * Order of precedence::
840 @node Changing all contexts of the same type
841 @unnumberedsubsubsec Changing all contexts of the same type
843 @cindex \context in \layout block
847 The default context settings which are to be used for typesetting in
848 @code{Score}, @code{Staff}, @code{Voice} and other contexts may be
849 specified in a @code{\context} block within any @code{\layout}
852 Settings for Midi output as opposed to typesetting will have to be
853 separately specified in @code{\midi} blocks (see @ref{Output
854 definitions - blueprints for contexts}).
856 The @code{\layout} block should be placed within the @code{\score}
857 block to which it is to apply, after the music.
863 [context settings for all Voice contexts]
867 [context settings for all Staff contexts]
872 The following types of settings may be specified:
876 An @code{\override} command, but with the context name omitted
878 @lilypond[quote,verbatim]
881 a'4^"Thicker stems" a a a
887 \override Stem.thickness = #4.0
894 Directly setting a context property
896 @lilypond[quote,verbatim]
899 a'4^"Smaller font" a a a
912 A predefined command such as @code{\dynamicUp} or a music
913 expression like @code{\accidentalStyle dodecaphonic}
915 @lilypond[quote,verbatim]
918 a'4^"Dynamics above" a a a
928 \accidentalStyle dodecaphonic
935 A user-defined variable containing a @code{\with} block; for details
936 of the @code{\with} block see
937 @ref{Changing just one specific context}.
939 @lilypond[quote,verbatim]
940 StaffDefaults = \with {
947 a'4^"Smaller font" a a a
962 Property-setting commands can be placed in a @code{\layout} block
963 without being enclosed in a @code{\context} block. Such settings
964 are equivalent to including the same property-setting commands at
965 the start of every context of the type specified. If no context
966 is specified @emph{every} bottom-level context is affected, see
967 @ref{Bottom-level contexts - voices}. The syntax of a
968 property-setting command in a @code{\layout} block is the same as
969 the same command written in the music stream.
971 @lilypond[quote,verbatim]
975 a'4^"Smaller font" a a a
980 \accidentalStyle dodecaphonic
982 \override Voice.Stem.thickness = #4.0
988 @node Changing just one specific context
989 @unnumberedsubsubsec Changing just one specific context
994 The context properties of just one specific context instance can be
995 changed in a @code{\with} block. All other context instances of the
996 same type retain the default settings built into LilyPond and modified
997 by any @code{\layout} block within scope. The @code{\with} block
998 must be placed immediately after the @code{\new} @var{context-type}
1002 \new Staff \with @{ [context settings for this context instance only] @}
1008 Alternatively, if the music is being entered using the short form of the
1009 input mode-specifying commands, e.g. @code{\chords} rather than
1010 @code{\chordmode}, the @code{\with} command must be placed immediately
1011 after the mode-specifying command:
1014 \chords \with @{ [context settings for this (implicit) context instance only] @}
1021 as it is the implicit context created by these short forms which should
1022 be modified. The same consideration applies to the other input
1023 mode-specifying short forms (@code{\drums}, @code{\figures}), see
1026 Since context modifications specified in @code{\with} blocks are inside
1027 music, they will affect @emph{all} outputs (typesetting @emph{and}
1028 Midi) as opposed to changes within an output definition.
1030 The following types of settings may be specified:
1034 An @code{\override} command, but with the context name omitted
1036 @lilypond[quote,verbatim]
1039 \new Voice \with { \override Stem.thickness = #4.0 }
1042 a'4^"Thick stems" a a a
1051 Directly setting a context property
1053 @lilypond[quote,verbatim]
1058 a'4^"Default font" a a a
1062 \new Staff \with { fontSize = #-4 }
1065 a'4^"Smaller font" a a a
1074 A predefined command such as @code{\dynamicUp}
1076 @lilypond[quote,verbatim]
1082 a'4^"Dynamics below" a a a
1087 \new Staff \with { \accidentalStyle dodecaphonic }
1089 \new Voice \with { \dynamicUp }
1092 a'4^"Dynamics above" a a a
1107 @node Order of precedence
1108 @unnumberedsubsubsec Order of precedence
1110 The value of a property which applies at a particular time is
1111 determined as follows:
1115 if an @code{\override} or @code{\set} command in the input stream is
1116 in effect that value is used,
1119 otherwise the default value taken from a @code{\with} statement
1120 on the context initiation statement is used,
1123 otherwise the default value taken from the most recent appropriate
1124 @code{\context} block in the @code{\layout} or @code{\midi} blocks
1128 otherwise the LilyPond built-in default is used.
1133 @rlearning{Modifying context properties}.
1136 @ref{Contexts explained},
1137 @ref{Bottom-level contexts - voices},
1138 @ref{The set command},
1139 @ref{The override command},
1140 @ref{The layout block,,The @code{@bs{}layout} block}.
1143 @node Defining new contexts
1144 @subsection Defining new contexts
1146 @cindex contexts, defining new
1147 @cindex engravers, including in contexts
1156 Specific contexts, like @code{Staff} and @code{Voice}, are made from
1157 simple building blocks. It is possible to create new types of
1158 contexts with different combinations of engraver plug-ins.
1160 The next example shows how to build a different type of
1161 @code{Voice} context from scratch. It will be similar to
1162 @code{Voice}, but only prints centered slash note heads. It can be used
1163 to indicate improvisation in jazz pieces,
1165 @lilypond[quote,ragged-right]
1166 \layout { \context {
1168 \type "Engraver_group"
1169 \consists "Note_heads_engraver"
1170 \consists "Rhythmic_column_engraver"
1171 \consists "Text_engraver"
1172 \consists "Pitch_squash_engraver"
1173 squashedPosition = #0
1174 \override NoteHead.style = #'slash
1179 \accepts "ImproVoice"
1183 a'4 d8 bes8 \new ImproVoice { c4^"ad lib" c
1184 c4 c^"undress" c_"while playing :)" c }
1190 These settings are defined within a @code{\context} block inside a
1191 @code{\layout} block,
1201 In the following discussion, the example input shown should go in place
1202 of the @dots{} in the previous fragment.
1204 First it is necessary to define a name for the new context:
1210 Since it is similar to the @code{Voice} context, we want commands that
1211 work in (existing) @code{Voice} contexts to continue working. This is
1212 achieved by giving the new context an alias of @code{Voice},
1218 The context will print notes and instructive texts, so we need to add
1219 the engravers which provide this functionality, plus the engraver which
1220 groups notes, stems and rests which occur at the same musical moment
1224 \consists "Note_heads_engraver"
1225 \consists "Text_engraver"
1226 \consists "Rhythmic_column_engraver"
1229 The note heads should all be placed on the center line,
1232 \consists "Pitch_squash_engraver"
1233 squashedPosition = #0
1236 The @code{Pitch_squash_engraver} modifies note heads (created
1237 by the @code{Note_heads_engraver}) and sets their vertical
1238 position to the value of @code{squashedPosition}, in this
1239 case@tie{}@code{0}, the center line.
1241 The notes look like a slash, and have no stem,
1244 \override NoteHead.style = #'slash
1248 All these plug-ins have to communicate under the control of the
1249 context. The mechanisms with which contexts communicate are
1250 established by declaring the context @code{\type}. Within a
1251 @code{\layout} block, most contexts will be of type
1252 @code{Engraver_group}. Some special contexts and contexts in
1253 @code{\midi} blocks use other context types. Copying and
1254 modifying an existing context definition will also fill in the
1255 type. Since this example creates a definition from scratch, it
1256 needs to be specified explicitly.
1259 \type "Engraver_group"
1262 Put together, we get
1267 \type "Engraver_group"
1268 \consists "Note_heads_engraver"
1269 \consists "Text_engraver"
1270 \consists "Rhythmic_column_engraver"
1271 \consists "Pitch_squash_engraver"
1272 squashedPosition = #0
1273 \override NoteHead.style = #'slash
1280 Contexts form hierarchies. We want to place the @code{ImproVoice}
1281 context within the @code{Staff} context, just like normal @code{Voice}
1282 contexts. Therefore, we modify the @code{Staff} definition with the
1283 @code{\accepts} command,
1292 @funindex \inherit-acceptability
1293 Often when reusing an existing context definition, the resulting
1294 context can be used anywhere where the original context would have
1300 \inherit-acceptability @var{to} @var{from}
1305 will arrange to have contexts of type @var{to} accepted by all
1306 contexts also accepting @var{from}. For example, using
1311 \inherit-acceptability "ImproVoice" "Voice"
1316 will add an @code{\accepts} for @code{ImproVoice} to both
1317 @code{Staff} and @code{RhythmicStaff} definitions.
1320 The opposite of @code{\accepts} is @code{\denies},
1321 which is sometimes needed when reusing existing context definitions.
1323 Arranging the required pieces into a @code{\layout} block leaves
1332 \inherit-acceptability "ImproVoice" "Voice"
1336 Then the output at the start of this subsection can be entered as
1344 c c_"while playing :)"
1350 To complete this example, changes affecting the context hierarchy
1351 should be repeated in a @code{\midi} block so that Midi output
1352 depends on the same context relations.
1356 Internals Reference:
1357 @rinternals{Note_heads_engraver},
1358 @rinternals{Text_engraver},
1359 @rinternals{Rhythmic_column_engraver},
1360 @rinternals{Pitch_squash_engraver}.
1363 @node Context layout order
1364 @subsection Context layout order
1366 @cindex contexts, layout order
1370 Contexts are normally positioned in a system from top to bottom
1371 in the order in which they are encountered in the input file. When
1372 contexts are nested, the outer context will include inner nested
1373 contexts as specified in the input file, provided the inner contexts
1374 are included in the outer context's @qq{accepts} list. Nested
1375 contexts which are not included in the outer context's @qq{accepts}
1376 list will be repositioned below the outer context rather than nested
1379 The @qq{accepts} list of a context can be changed with the
1380 @code{\accepts} or @code{\denies} commands. @code{\accepts} adds a
1381 context to the @qq{accepts} list and @code{\denies} removes a context
1384 For example, a square-braced staff group is not usually found within a
1385 curved-braced staff with connecting staff bars, and a @code{GrandStaff}
1386 does not accept a @code{StaffGroup} inside it by default.
1388 @lilypond[verbatim,quote]
1395 \new Staff { \set Staff.instrumentName = bottom f'1 }
1400 However, by using the @code{\accepts} command, @code{StaffGroup} can be
1401 added to the @code{GrandStaff} context:
1403 @lilypond[verbatim,quote]
1410 \new Staff { \set Staff.instrumentName = bottom f'1 }
1415 \accepts "StaffGroup"
1421 @code{\denies} is mainly used when a new context is being based on
1422 another, but the required nesting differs. For example, the
1423 @code{VaticanaStaff} context is based on the @code{Staff} context, but
1424 with the @code{VaticanaVoice} context substituted for the @code{Voice}
1425 context in the @qq{accepts} list.
1427 @cindex contexts, implicit
1428 @cindex implicit contexts
1429 @funindex \defaultchild
1431 Note that a context will be silently created implicitly if a
1432 command is encountered when there is no suitable context available
1435 Within a context definition, the type of subcontext to be
1436 implicitly created is specified using @code{\defaultchild}. A
1437 number of music events require a @samp{Bottom} context: when such
1438 an event is encountered, subcontexts are created recursively until
1439 reaching a context with no @samp{defaultchild} setting.
1441 Implicit context creation can at times give rise to unexpected new
1442 staves or scores. Using @code{\new} to create contexts explicitly
1443 avoids those problems.
1445 @cindex alignAboveContext
1446 @cindex alignBelowContext
1447 @funindex alignAboveContext
1448 @funindex alignBelowContext
1450 Sometimes a context is required to exist for just a brief period, a
1451 good example being the staff context for an ossia. This is usually
1452 achieved by introducing the context definition at the appropriate
1453 place in parallel with corresponding section of the main music.
1454 By default, the temporary context will be placed below all the
1455 existing contexts. To reposition it above the context called
1456 @qq{main}, it should be defined like this:
1459 \new Staff \with @{ alignAboveContext = #"main" @}
1462 A similar situation arises when positioning a temporary lyrics
1463 context within a multi-staved layout such as a @code{ChoirStaff},
1464 for example, when adding a second verse to a repeated section.
1465 By default the temporary lyrics context will be placed beneath the
1466 lower staves. By defining the temporary lyrics context with
1467 @code{alignBelowContext} it can be positioned correctly beneath
1468 the (named) lyrics context containing the first verse.
1470 Examples showing this repositioning of temporary contexts can be
1471 found elsewhere --- see @rlearning{Nesting music expressions},
1472 @ref{Modifying single staves} and @ref{Techniques specific to lyrics}.
1476 @rlearning{Nesting music expressions}.
1479 @ref{Modifying single staves},
1480 @ref{Techniques specific to lyrics}.
1483 @rprogram{An extra staff appears}.
1486 @file{ly/engraver-init.ly}.
1489 @node Explaining the Internals Reference
1490 @section Explaining the Internals Reference
1493 * Navigating the program reference::
1494 * Layout interfaces::
1495 * Determining the grob property::
1496 * Naming conventions::
1499 @node Navigating the program reference
1500 @subsection Navigating the program reference
1502 @c TODO remove this (it's in the LM)
1503 @c Replace with more factual directions
1505 Suppose we want to move the fingering indication in the fragment
1508 @lilypond[quote,fragment,verbatim]
1512 If you visit the documentation on fingering instructions (in
1513 @ref{Fingering instructions}), you will notice:
1518 Internals Reference: @rinternals{Fingering}.
1523 @c outdated info; probably will delete.
1525 This fragment points to two parts of the program reference: a page
1526 on @code{FingeringEvent} and one on @code{Fingering}.
1528 The page on @code{FingeringEvent} describes the properties of the music
1529 expression for the input @w{@code{-2}}. The page contains many links
1530 forward. For example, it says
1533 Accepted by: @rinternals{Fingering_engraver},
1537 That link brings us to the documentation for the Engraver, the
1541 This engraver creates the following layout objects: @rinternals{Fingering}.
1544 In other words, once the @code{FingeringEvent}s are interpreted, the
1545 @code{Fingering_engraver} plug-in will process them.
1549 @c I can't figure out what this is supposed to mean. -gp
1551 The @code{Fingering_engraver} is also listed to create
1552 @rinternals{Fingering} objects,
1554 @c old info? it doesn't make any sense to me with our current docs.
1556 second bit of information listed under @b{See also} in the Notation
1561 The programmer's reference is available as an HTML document. It is
1562 highly recommended that you read it in HTML form, either online or
1563 by downloading the HTML documentation. This section will be much more
1564 difficult to understand if you are using the
1568 Follow the link to @rinternals{Fingering}. At the top of the
1572 Fingering objects are created by: @rinternals{Fingering_engraver} and
1573 @rinternals{New_fingering_engraver}.
1576 By following related links inside the program reference, we can follow the
1577 flow of information within the program:
1581 @item @rinternals{Fingering}:
1582 @rinternals{Fingering} objects are created by:
1583 @rinternals{Fingering_engraver}
1585 @item @rinternals{Fingering_engraver}:
1586 Music types accepted: @rinternals{fingering-event}
1588 @item @rinternals{fingering-event}:
1589 Music event type @code{fingering-event} is in Music expressions named
1590 @rinternals{FingeringEvent}
1593 This path goes against the flow of information in the program: it
1594 starts from the output, and ends at the input event. You could
1595 also start at an input event, and read with the flow of
1596 information, eventually ending up at the output object(s).
1598 The program reference can also be browsed like a normal document. It
1599 contains chapters on
1601 @rinternals{Music definitions},
1604 @code{Music definitions}
1606 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1607 chapter lists all the definitions used and all properties that may be
1611 @node Layout interfaces
1612 @subsection Layout interfaces
1614 @cindex interface, layout
1615 @cindex layout interface
1618 The HTML page that we found in the previous section describes the
1619 layout object called @rinternals{Fingering}. Such an object is a
1620 symbol within the score. It has properties that store numbers (like
1621 thicknesses and directions), but also pointers to related objects. A
1622 layout object is also called a @emph{Grob}, which is short for Graphical
1623 Object. For more details about Grobs, see @rinternals{grob-interface}.
1625 The page for @code{Fingering} lists the definitions for the
1626 @code{Fingering} object. For example, the page says
1629 @code{padding} (dimension, in staff space):
1635 which means that the number will be kept at a distance of at least 0.5
1639 Each layout object may have several functions as a notational or
1640 typographical element. For example, the Fingering object
1641 has the following aspects
1645 Its size is independent of the horizontal spacing, unlike slurs or beams.
1648 It is a piece of text. Granted, it is usually a very short text.
1651 That piece of text is typeset with a font, unlike slurs or beams.
1654 Horizontally, the center of the symbol should be aligned to the
1655 center of the note head.
1658 Vertically, the symbol is placed next to the note and the staff.
1661 The vertical position is also coordinated with other superscript
1662 and subscript symbols.
1665 Each of these aspects is captured in so-called @emph{interface}s,
1666 which are listed on the @rinternals{Fingering} page at the bottom
1669 This object supports the following interfaces:
1670 @rinternals{item-interface},
1671 @rinternals{self-alignment-interface},
1672 @rinternals{side-position-interface}, @rinternals{text-interface},
1673 @rinternals{text-script-interface}, @rinternals{font-interface},
1674 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1677 Clicking any of the links will take you to the page of the respective
1678 object interface. Each interface has a number of properties. Some of
1679 them are not user-serviceable (@q{Internal properties}), but others
1682 We have been talking of @emph{the} @code{Fingering} object, but actually it
1683 does not amount to much. The initialization file (see
1684 @rlearning{Other sources of information})
1685 @file{scm/define-grobs.scm} shows the soul of the @q{object},
1690 (avoid-slur . around)
1691 (slur-padding . 0.2)
1692 (staff-padding . 0.5)
1693 (self-alignment-X . 0)
1694 (self-alignment-Y . 0)
1695 (script-priority . 100)
1696 (stencil . ,ly:text-interface::print)
1697 (direction . ,ly:script-interface::calc-direction)
1698 (font-encoding . fetaText)
1699 (font-size . -5) ; don't overlap when next to heads.
1700 (meta . ((class . Item)
1701 (interfaces . (finger-interface
1703 text-script-interface
1705 side-position-interface
1706 self-alignment-interface
1707 item-interface))))))
1711 As you can see, the @code{Fingering} object is nothing more than a
1712 bunch of variable settings, and the webpage in the Internals Reference
1713 is directly generated from this definition.
1716 @node Determining the grob property
1717 @subsection Determining the grob property
1719 @c TODO remove this (it's in the LM)
1720 @c Replace with more factual directions
1722 Recall that we wanted to change the position of the @b{2} in
1724 @lilypond[quote,fragment,verbatim]
1728 Since the @b{2} is vertically positioned next to its note, we have to
1729 meddle with the interface associated with this positioning. This is
1730 done using @code{side-position-interface}. The page for this interface
1734 @code{side-position-interface}
1736 Position a victim object (this one) next to other objects (the
1737 support). The property @code{direction} signifies where to put the
1738 victim object relative to the support (left or right, up or down?)
1743 Below this description, the variable @code{padding} is described as
1748 (dimension, in staff space)
1750 Add this much extra space between objects that are next to each other.
1754 By increasing the value of @code{padding}, we can move the fingering
1755 away from the note head. The following command will insert @qq{three
1756 staff spaces} worth of distance between the note and a fingering mark:
1759 \once \override Voice.Fingering.padding = #3
1762 Inserting the padding before the fingering object is created results in
1765 @lilypond[quote,fragment,verbatim]
1766 \once \override Voice.Fingering.padding = #3
1770 In this case, the context for this tweak is @code{Voice}. See
1771 @rinternals{Fingering_engraver} plug-in, which says:
1774 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1778 @node Naming conventions
1779 @subsection Naming conventions
1781 Another thing that is needed, is an overview of the various naming
1785 @item scheme functions: lowercase-with-hyphens (also includes one-word
1788 @item LilyPond-specific scheme functions: ly:plus-scheme-style
1790 @item music events, music classes and music properties:
1793 @item Grob interfaces: scheme-style
1795 @item backend properties: scheme-style (but X and Y!)
1797 @item contexts (and MusicExpressions and grobs): Capitalized or
1800 @item context properties: lowercaseFollowedByCamelCase
1802 @item engravers: Capitalized_followed_by_lowercase_and_with_underscores
1805 Questions to be answered:
1808 @item Which of these are conventions and which are rules?
1810 @item Which are rules of the underlying language, and which are
1814 @node Modifying properties
1815 @section Modifying properties
1817 @c TODO change the menu and subsection node names to use
1818 @c backslash once the new macro to handle the refs
1819 @c is available. Need to find and change all refs at
1820 @c the same time. -td
1823 * Overview of modifying properties::
1825 * The override command::
1826 * The tweak command::
1827 * set versus override::
1828 * The offset command::
1829 * Modifying alists::
1833 @node Overview of modifying properties
1834 @subsection Overview of modifying properties
1836 Each context is responsible for creating certain types of graphical
1837 objects. The settings used for printing these objects are also stored by
1838 context. By changing these settings, the appearance of objects can be
1841 There are two different kinds of properties stored in contexts:
1842 context properties and grob properties. Context properties are
1843 properties that apply to the context as a whole and control
1844 how the context itself is displayed. In contrast, grob properties
1845 apply to specific grob types that will be displayed in the context.
1847 The @code{\set} and @code{\unset} commands are used to change values
1848 for context properties. The @code{\override} and @code{\revert}
1849 commands are used to change values for grob properties.
1852 The syntax for this is
1855 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1858 Here @var{name} is the name of a graphical object, like
1859 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1860 variable of the formatting system (@q{grob property} or @q{layout
1861 property}). The latter is a symbol, so it must be quoted. The
1862 subsection @ref{Modifying properties}, explains what to fill in
1863 for @var{name}, @var{property}, and @var{value}. Here we only
1864 discuss the functionality of this command.
1869 \override Staff.Stem.thickness = #4.0
1873 makes stems thicker (the default is 1.3, with staff line thickness as a
1874 unit). Since the command specifies @code{Staff} as context, it only
1875 applies to the current staff. Other staves will keep their normal
1876 appearance. Here we see the command in action:
1878 @lilypond[quote,fragment,verbatim]
1880 \override Staff.Stem.thickness = #4.0
1886 The @code{\override} command changes the definition of the @code{Stem}
1887 within the current @code{Staff}. After the command is interpreted
1888 all stems are thickened.
1890 Analogous to @code{\set}, the @var{context} argument may be left out,
1891 causing the default context @code{Voice} to be used. Adding
1892 @code{\once} applies the change during one timestep only.
1894 @lilypond[quote,fragment,verbatim]
1896 \once \override Stem.thickness = #4.0
1901 The @code{\override} must be done before the object is
1902 started. Therefore, when altering @emph{Spanner} objects such as slurs
1903 or beams, the @code{\override} command must be executed at the moment
1904 when the object is created. In this example,
1906 @lilypond[quote,fragment,verbatim]
1907 \override Slur.thickness = #3.0
1909 \override Beam.beam-thickness = #0.6
1914 the slur is fatter but the beam is not. This is because the command for
1915 @code{Beam} comes after the Beam is started, so it has no effect.
1917 Analogous to @code{\unset}, the @code{\revert} command for a context
1918 undoes an @code{\override} command; like with @code{\unset}, it only
1919 affects settings that were made in the same context. In other words, the
1920 @code{\revert} in the next example does not do anything.
1923 \override Voice.Stem.thickness = #4.0
1924 \revert Staff.Stem.thickness
1927 Some tweakable options are called @q{subproperties} and reside inside
1928 properties. To tweak those, use commands of the form
1930 @c leave this as a long long
1932 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1939 \override Stem.details.beamed-lengths = #'(4 4 3)
1945 Internals Reference:
1946 @rinternals{Backend},
1947 @rinternals{All layout objects},
1948 @rinternals{OverrideProperty},
1949 @rinternals{RevertProperty},
1950 @rinternals{PropertySet}.
1953 The back-end is not very strict in type-checking object properties.
1954 Cyclic references in Scheme values for properties can cause hangs
1955 or crashes, or both.
1958 @node The set command
1959 @subsection The @code{@bs{}set} command
1963 @cindex changing properties
1965 Each context has a set of @emph{properties}, variables contained
1966 in that context. Context properties are changed with the @code{\set}
1967 command, which has the following syntax:
1970 \set @var{context}.@var{property} = #@var{value}
1973 @var{value} is a Scheme object, which is why it must be preceded by
1974 the @code{#}@tie{}character.
1976 Contexts properties are usually named in
1977 @code{studlyCaps}. They mostly control the translation from
1978 music to notation, e.g., @code{localAlterations} (for determining
1979 whether to print accidentals), or @code{measurePosition} (for
1980 determining when to print a bar line). Context properties can
1981 change value over time while interpreting a piece of music;
1982 @code{measurePosition} is an obvious example of
1983 this. Context properties are modified with @code{\set}.
1985 For example, multimeasure rests will be combined into a single bar
1986 if the context property @code{skipBars} is set to @code{#t}:
1988 @lilypond[quote,fragment,verbatim]
1990 \set Score.skipBars = ##t
1994 If the @var{context} argument is left out, then the property will be
1995 set in the current bottom context (typically @code{ChordNames},
1996 @code{Voice}, @code{TabVoice}, or @code{Lyrics}).
1998 @lilypond[quote,fragment,verbatim]
1999 \set Score.autoBeaming = ##f
2002 \set autoBeaming = ##t
2010 The change is applied @q{on-the-fly}, during the music, so that the
2011 setting only affects the second group of eighth notes.
2013 Note that the bottom-most context does not always contain the property
2014 that you wish to change -- for example, attempting to set the
2015 @code{skipBars} property of the default bottom context, in this case
2016 @code{Voice}, will have no effect, because skipBars is a property of
2017 the @code{Score} context.
2019 @lilypond[quote,fragment,verbatim]
2025 Contexts are hierarchical, so if an enclosing context was specified, for
2026 example @code{Staff}, then the change would also apply to all
2027 @code{Voice}s in the current staff.
2031 The @code{\unset} command:
2034 \unset @var{context}.@var{property}
2038 is used to remove the definition of @var{property} from
2039 @var{context}. This command removes
2040 the definition only if it is set in @var{context}.
2041 Properties that have been set in enclosing contexts will
2042 not be altered by an unset in an enclosed context:
2044 @lilypond[quote,fragment,verbatim]
2045 \set Score.autoBeaming = ##t
2049 \unset Score.autoBeaming
2057 Like @code{\set}, the @var{context} argument does not have to be
2058 specified for a bottom context, so the two statements
2061 \set Voice.autoBeaming = ##t
2062 \set autoBeaming = ##t
2066 are equivalent if the current bottom context is @code{Voice}.
2070 Preceding a @code{\set} or @code{\unset} command by @code{\once}
2071 makes the setting apply to only a single time-step:
2073 @lilypond[quote,fragment,verbatim]
2075 \once \set fontSize = #4.7
2080 A full description of all available context properties is in the
2081 internals reference, see
2083 @rinternals{Tunable context properties}.
2086 Translation @expansion{} Tunable context properties.
2090 Internals Reference:
2091 @rinternals{Tunable context properties}.
2094 @node The override command
2095 @subsection The @code{\override} command
2097 @cindex grob properties
2098 @cindex properties, grob
2101 There is a special type of context property: the grob
2102 description. Grob descriptions are named in @code{StudlyCaps}
2103 (starting with capital letters). They contain the
2104 @q{default settings} for a particular kind of grob as an
2105 association list. See @file{scm/define-grobs.scm}
2106 to see the settings for each grob description. Grob descriptions
2107 are modified with @code{\override}.
2109 The syntax for the @code{\override} command is
2112 \override [@var{context}.]@var{GrobName}.@var{property} = #@var{value}
2115 For example, we can increase the thickness of a note stem by
2116 overriding the @code{thickness} property of the @code{Stem}
2119 @lilypond[quote,fragment,verbatim]
2121 \override Voice.Stem.thickness = #3.0
2125 If no context is specified in an @code{\override}, the bottom
2128 @lilypond[quote,fragment,verbatim]
2129 \override Staff.Stem.thickness = #3.0
2133 \override Stem.thickness = #0.5
2142 Some tweakable options are called @q{subproperties} and reside inside
2143 properties. To tweak those, use commands in the form
2146 \override Stem.details.beamed-lengths = #'(4 4 3)
2149 or to modify the ends of spanners, use a form like these
2152 \override TextSpanner.bound-details.left.text = #"left text"
2153 \override TextSpanner.bound-details.right.text = #"right text"
2157 @cindex reverting overrides
2158 @cindex overrides, reverting
2160 The effects of @code{\override} can be undone by @code{\revert}.
2162 The syntax for the @code{\revert} command is
2165 \revert [@var{context}.]@var{GrobName}.@var{property}
2170 @lilypond[quote,verbatim]
2173 \override Voice.Stem.thickness = #3.0
2175 \revert Voice.Stem.thickness
2180 The effects of @code{\override} and @code{\revert} apply to all
2181 grobs in the affected context from the current time forward:
2183 @lilypond[quote,verbatim]
2187 \override Staff.Stem.thickness = #3.0
2192 \revert Staff.Stem.thickness
2199 @cindex overriding for only one moment
2201 @code{\once} can be used with @code{\override} or @code{\revert}
2202 to affect only the current time step:
2204 @lilypond[quote,verbatim]
2207 \override Stem.thickness = #3.0
2212 \once \override Stem.thickness = #3.0
2220 Commands which change output generally look like
2223 \override Voice.Stem.thickness = #3.0
2227 To construct this tweak we must determine these bits of information:
2230 @item the context: here @code{Voice}.
2231 @item the layout object: here @code{Stem}.
2232 @item the layout property: here @code{thickness}.
2233 @item a sensible value: here @code{3.0}.
2236 @cindex internal documentation
2237 @cindex finding graphical objects
2238 @cindex graphical object descriptions
2241 @cindex internal documentation
2243 For many properties, regardless of the data type of the property, setting the
2244 property to false (@code{#f}) will result in turning it off, causing
2245 LilyPond to ignore that property entirely. This is particularly useful for
2246 turning off grob properties which may otherwise be causing problems.
2248 We demonstrate how to glean this information from the notation manual
2249 and the program reference.
2253 Internals Reference:
2254 @rinternals{Backend}
2257 @node The tweak command
2258 @subsection The @code{\tweak} command
2263 Changing grob properties
2264 with @code{\override} causes the changes to apply to all of the
2265 given grobs in the context at the moment the change applies.
2266 Sometimes, however, it is desirable to have changes apply to just
2267 one grob, rather than to all grobs in the affected context. This is
2268 accomplished with the @code{\tweak} command, which has the following
2272 \tweak [@var{layout-object}.]@var{grob-property} @var{value}
2275 Specifying @var{layout-object} is optional.
2276 The @code{\tweak} command applies to the music object that immediately
2277 follows @var{value} in the music stream.
2280 In some cases, it is possible to take a short-cut for tuning
2281 graphical objects. For objects that are created directly from
2282 an item in the input file, you can use the @code{\tweak} command.
2285 @lilypond[verbatim,quote]
2291 \tweak duration-log #1
2301 The main use of the @code{\tweak} command is to modify just
2302 one of a number of notation elements which start at the same musical
2303 moment, like the notes of a chord, or tuplet brackets which start
2306 The @code{\tweak} command sets a property in the following object
2307 directly, without requiring the grob name or context to be
2308 specified. For this to work, it is necessary for the @code{\tweak}
2309 command to remain immediately adjacent to the object to which it is
2310 to apply after the input file has been converted to a music stream.
2311 This is often not the case, as many additional elements are inserted
2312 into the music stream implicitly. For example, when a note which is
2313 not part of a chord is processed, LilyPond implicitly inserts a
2314 @code{ChordEvent} event before the note, so separating the tweak
2315 from the note. However, if chord symbols are placed round the
2316 tweak and the note, the @code{\tweak} command comes after the
2317 @code{ChordEvent} in the music stream, so remaining adjacent to the
2318 note, and able to modify it.
2322 @lilypond[verbatim,fragment,quote]
2323 <\tweak color #red c''>4
2329 @lilypond[verbatim,fragment,quote]
2330 \tweak color #red c''4
2335 For an introduction to the syntax and uses of the tweak command
2336 see @rlearning{Tweaking methods}.
2338 When several similar items are placed at the same musical moment,
2339 the @code{\override} command cannot be used to modify just one of
2340 them -- this is where the @code{\tweak} command must be used.
2341 Items which may appear more than once at the same musical moment
2342 include the following:
2344 @c TODO expand to include any further uses of \tweak
2346 @item note heads of notes inside a chord
2347 @item articulation signs on a single note
2348 @item ties between notes in a chord
2349 @item tuplet brackets starting at the same time
2352 @c TODO add examples of these
2354 @cindex chord, modifying one note in
2356 In this example, the color of one note head and the type of another
2357 note head are modified within a single chord:
2359 @lilypond[verbatim,fragment,quote]
2364 \tweak duration-log #1
2369 @code{\tweak} can be used to modify slurs:
2371 @lilypond[verbatim,quote]
2372 \relative { c'-\tweak thickness #5 ( d e f) }
2376 For the @code{\tweak} command to work, it must
2377 remain immediately adjacent to the object to which it is
2378 to apply after the input file has been converted to a music stream.
2379 Tweaking a whole chord does not do anything since its music event
2380 only acts as a container, and all layout objects are created from events
2381 inside of the @code{EventChord}:
2383 @lilypond[verbatim,fragment,quote]
2384 \tweak color #red c''4
2385 \tweak color #red <c'' e''>4
2386 <\tweak color #red c'' e''>4
2389 The simple @code{\tweak} command cannot be used to modify any object
2390 that is not directly created from the input. In particular
2391 it will not affect stems, automatic
2392 beams or accidentals, since these are generated later by
2393 @code{NoteHead} layout objects rather than by music elements in the
2396 Such indirectly created layout objects can be tweaked using the form
2397 of the @code{\tweak} command in which the grob name is specified
2400 @lilypond[fragment,verbatim,quote]
2401 \tweak Stem.color #red
2402 \tweak Beam.color #green c''8 e''
2403 <c'' e'' \tweak Accidental.font-size #-3 ges''>4
2406 @code{\tweak} cannot be used to modify clefs or time
2407 signatures, since these become separated from any preceding
2408 @code{\tweak} command in the input stream by the automatic
2409 insertion of extra elements required to specify the context.
2411 Several @code{\tweak} commands may be placed before a
2412 notational element -- all affect it:
2414 @lilypond[verbatim,fragment,quote]
2416 -\tweak style #'dashed-line
2417 -\tweak dash-fraction #0.2
2418 -\tweak thickness #3
2424 The music stream which is generated from a section of an input file,
2425 including any automatically inserted elements, may be examined,
2426 see @rextend{Displaying music expressions}. This may be helpful in
2427 determining what may be modified by a @code{\tweak} command, or
2428 in determining how to adjust the input to make a @code{\tweak}
2433 @rlearning{Tweaking methods}.
2436 @rextend{Displaying music expressions}.
2440 @cindex tweaking control points
2441 @cindex control points, tweaking
2443 The @code{\tweak} command cannot be used to modify the control
2444 points of just one of several ties in a chord, other than the first
2445 one encountered in the input file.
2447 @node set versus override
2448 @subsection @code{\set} vs. @code{\override}
2450 @c TODO Should't a bunch of that be explained earlier?
2455 The @code{\set} and @code{\override} commands manipulate properties
2456 associated with contexts. In both cases, the properties follow a
2457 @emph{hierarchy of contexts}; properties that are not set themselves in
2458 a context will still show the values of their respective parent's
2461 The lifetime and value of a context property is dynamic and only
2462 available when music is being interpreted (i.e., @q{iterated}). At the
2463 time of the context's creation, properties are initialized from its
2464 corresponding definitions (along with any other modifications) of that
2465 context. Any subsequent changes are achieved with any
2466 @q{property-setting} commands that are within the music itself.
2468 Graphical Object (or @qq{grob}) definitions are a @emph{special}
2469 category of context properties as their structure and use is different
2470 from that of normal context properties. Unlike normal context
2471 properties, grob definitions are subdivided into @emph{grob properties}.
2473 Also, in contrast to normal context properties, grob definitions have
2474 their own internal @q{bookkeeping} used to keep track of their own
2475 individual grob properties and any sub-properties. This means that it
2476 is possible to define those parts within different contexts and yet
2477 still have the overall grob definition at the time of grob creation from
2478 all the pieces provided amongst the current context and its parent(s).
2480 A grob is usually created by an engraver at the time of interpreting a
2481 music expression and receives its initial properties from the current
2482 grob definition of the engraver's context. The engraver (or other
2483 @q{backend} parts of LilyPond) can then change (or add to) the grob's
2484 initial properties. However, this does not affect the context's own
2487 What LilyPond calls @emph{grob properties} in the context of
2488 @q{user-level} tweaks are really the properties of a @emph{context's}
2489 own grob definition.
2491 Grob definitions are accessed with a different set of commands and are
2492 manipulated using @code{\override} and @code{\revert} and have a name
2493 starting with a capital letter (e.g., @samp{NoteHead}); whereas normal
2494 context properties are manipulated using @code{\set} and @code{\unset}
2495 and are named starting with a lowercase letter.
2497 @cindex tweak, relation to @code{\override}
2499 @funindex \overrideProperty
2501 The commands @code{\tweak} and @code{\overrideProperty} change grob
2502 properties by bypassing all context properties completely and, instead,
2503 catch grobs as they are being created, setting properties on them for
2504 a music event (@code{\tweak}) or, in the case of
2505 @code{\overrideProperty} for a specific override.
2508 @node The offset command
2509 @subsection The @code{\offset} command
2513 @cindex defaults, offsetting
2515 While it is possible to set grob properties to new values with the
2516 @code{\override}, @code{\tweak}, and @code{\overrideProperty} commands,
2517 it is often more convenient to modify such properties relative to a
2518 default value. The @code{\offset} command is available for this
2521 The syntax for @code{\offset} is
2524 [-]\offset @var{property} @var{offsets} @var{item}
2527 The command works by adding the contents of @var{offsets} to the
2528 default setting of the property @var{property} of the grob indicated by
2531 Depending on the formulation of the command, @code{\offset} may act
2532 as either a @code{\tweak} or @code{\override}. The variations in
2533 usage are discussed after consideration is given to grob properties
2534 that may be used with @code{\offset}.
2536 @subsubsubheading{Properties which may be offset}
2538 Many, but not all, grob properties may be offset. If @var{property}
2539 cannot be offset, the object will remain unchanged and a warning will
2540 be issued. In such cases, @code{\override} or @code{\tweak} should be
2541 used to modify the object instead.
2543 One can work by trial and error and let the warnings be the guide to
2544 what may or may not be offset. A more systematic approach is possible,
2547 The following criteria determine whether a property can be modified with
2553 The property has a @q{default setting} in the grob's description. Such
2554 properties are listed for each grob in @rinternals{All layout objects}.
2555 (They are also found in @file{scm/define-grobs.scm}.)
2558 The property takes a numerical value. Numerical values include
2559 @code{number}, list of @code{number}s, @code{number-pair}, and
2560 @code{number-pair-list}. The pages at @rinternals{All layout objects}
2561 list the type of data characteristic to each property. It is immaterial
2562 whether the default setting is a function.
2565 The property cannot be a @q{subproperty}---a property residing within
2569 Properties set to infinite values cannot be offset. There is no
2570 sensible way to offset positive and negative infinity.
2573 The following examples consider several grob properties against the
2574 criteria outlined above.
2578 @item Properties that may be offset
2582 @item @code{Hairpin.height}
2584 This property is not a subproperty, and it is listed at
2585 @rinternals{Hairpin}. For a value, it takes @q{dimension, in staff
2586 space} set to @code{0.6666}---clearly a non-infinite @code{number}.
2588 @item @code{Arpeggio.positions}
2590 The page @rinternals{Arpeggio} lists a @code{positions} property which
2591 accepts a @q{pair of numbers}. It defaults to
2592 @code{ly:arpeggio::positions}---a callback which will be evaluated
2593 during the typesetting phase to yield a pair of numbers for any given
2594 @code{Arpeggio} object.
2598 @item Properties that may not be offset
2602 @item @code{Hairpin.color}
2604 There is no listing for @code{color} at @rinternals{Hairpin}.
2606 @item @code{Hairpin.circled-tip}
2608 The listing for @code{Hairpin.circled-tip} at @rinternals{Hairpin} shows
2609 that it takes a @code{boolean} value. Booleans are non-numerical.
2611 @item @code{Stem.details.lengths}
2613 Though listed at @rinternals{Stem} and defaulting to a list of
2614 @code{number}s, this is a @q{subproperty}. There is currently no
2615 support for @q{nested properties}.
2621 @subsubsubheading{@bs{}offset as an override}
2623 If @var{item} is a grob name like @code{Arpeggio} or
2624 @code{Staff.OttavaBracket}, the result is an @code{\override} of the
2625 specified grob-type.
2628 \offset @var{property} @var{offsets} [@var{context}.]@var{GrobName}
2631 Note that the leading hyphen is @emph{never} used with the @q{override}
2632 form, just as it is never used with the @code{\override} command itself.
2634 The following example uses the @q{override} form to lengthen the
2635 default arpeggios shown in the first measure to cover the extent of
2636 the chords more fully. The arpeggios are stretched by a half
2637 staff-space to top and bottom. Also shown is the same operation done on
2638 the first chord with an ordinary override of the @code{positions}
2639 property. This method is not at all expressive of the task of
2640 @q{stretching by a half staff-space}, as the endpoints must be specified
2641 with absolute rather than relative coordinates. Furthermore, individual
2642 overrides would be needed for the other chords, as they vary in size and
2645 @lilypond[quote,verbatim]
2647 <c' e' g'>\arpeggio <a' c'' e''>\arpeggio
2648 <d' f' a' c''>\arpeggio <c' e' g' b' d'' f'' a''>\arpeggio
2654 \offset positions #'(-0.5 . 0.5) Arpeggio
2657 \once \override Arpeggio.positions = #'(-3.5 . -0.5)
2658 <c' e' g'>1\arpeggio
2663 In its @q{override} usage, @code{\offset} may be prefaced with
2664 @code{\once} or @code{\temporary} and reverted using @code{\revert} with
2665 @var{property}. This follows from the fact that @code{\offset} actually
2666 creates an @code{\override} of @var{property}.
2668 @lilypond[quote,verbatim]
2669 music = { c'8\< d' e' f'\! }
2673 \offset height 1 Hairpin
2676 \revert Hairpin.height
2679 \once \offset height 1 Hairpin
2682 \override Hairpin.height = 0.2
2684 \temporary \offset height 2 Hairpin
2687 \revert Hairpin.height
2693 Also like @code{\override}, the @q{override} form of @code{\offset} may
2694 be used with @code{\undo} and @code{\single}.
2696 @lilypond[quote,verbatim]
2697 longStem = \offset length 6 Stem
2700 \longStem c'4 c''' c' c''
2702 \undo \longStem c'4 c''' c' c''
2704 \single \longStem c'4 c''' c' c''
2709 @subsubsubheading{@bs{}offset as a tweak}
2711 If @var{item} is a music expression such as @code{(} or
2712 @code{\arpeggio}, the result is the same music expression with a tweak
2716 [-]\offset [@var{GrobName}.]@var{property} @var{offsets} @var{music-expression}
2719 The syntax of @code{\offset} in its @q{tweak} form is analogous to the
2720 @code{\tweak} command itself, both in ordering and in the presence or
2721 absence of the leading hyphen.
2723 The following example uses the @q{tweak} form to adjust the vertical
2724 position of the @code{BreathingSign} object. Compare this with the
2725 ordinary @code{\tweak} command also demonstrated. The syntax is
2726 equivalent; however, the output of @code{\tweak} is less intuitive,
2727 since @code{BreathingSign.Y-offset} is calculated from the middle
2728 staff-line. It is not necessary to know how @code{Y-offset} is
2729 calculated when using @code{\offset}.
2731 @lilypond[quote,verbatim]
2736 \offset Y-offset 2 \breathe
2738 \tweak Y-offset 3 \breathe
2742 In the previous example, the tweaked objects were created directly from
2743 the user input: the @code{\breathe} command was an explicit instruction
2744 to return a @code{BreathingSign} object. Since the focus of the command
2745 was unambiguous, there was no need to specify the object's name. When
2746 an object is @emph{indirectly} created, however, it is necessary to
2747 include the grob's name. This is the same as for the @code{\tweak}
2750 In the following example, the @code{Beam} object is lowered two
2751 staff-spaces by applying @code{\offset} to the @code{positions}
2754 The first application of @code{\offset} requires that the grob's name
2755 be included, because nothing in the input explicitly creates the
2756 beam. In the second application, the beam is created manually with the
2757 music expression @code{[}; therefore, the grob's name is not needed.
2758 (Also illustrated is a shorthand: a single @code{number} will be applied
2759 to both members of a @code{number-pair}.)
2761 @lilypond[quote,verbatim]
2764 \offset Beam.positions #'(-2 . -2)
2767 c''8-\offset positions #-2 [ g'' e'' d'']
2771 @subsubsubheading{@bs{}offset with broken spanners}
2773 Independently modifying segments of a spanner extending over a line
2774 break or breaks is also possible. In this case, @var{offsets}
2775 takes a list of values of the property's required data type.
2777 The @code{\offset} command used in this manner is similar to the
2778 @code{\alterBroken} command. (See @ref{Modifying broken spanners}.)
2779 In contrast with @code{\alterBroken}, however, the values given to
2780 @code{\offset} are relative, not absolute.
2782 The following example displaces the @q{broken} @code{OttavaBracket}
2783 object through its @code{staff-padding} property. Since the property
2784 takes a @code{number}, @var{offsets} is provided with a list of
2785 @code{number}s to account for the two segments created by the line
2786 break. The slur piece on the first line is effectively untouched since
2787 @code{0} is added to its default value. The segment on the second
2788 line is raised two staff-spaces from its default height. The default
2789 height happens to be @code{2}, though it is not necesssary to know this.
2791 @lilypond[quote,verbatim]
2793 \offset staff-padding #'(0 3) Staff.OttavaBracket
2801 The following example mimics the effect of the @code{\shape} command by
2802 offsetting the @code{control-points} property of the @code{Slur} object.
2803 Here, @var{offsets} is a list of @code{number-pair-list}s, one for each
2804 slur segment. This example achieves a result identical to the
2805 corresponding illustration at @ref{Modifying shapes}.
2807 @lilypond[quote,verbatim]
2809 c'4-\offset control-points #'(
2810 ((0 . 0) (0 . 0) (0 . 0) (0 . 1))
2811 ((0.5 . 1.5) (1 . 0) (0 . 0) (0 . -1.5))
2819 @node Modifying alists
2820 @subsection Modifying alists
2822 Some user-configurable properties are internally represented as
2823 @emph{alists} (association lists), which store pairs of
2824 @emph{keys} and @emph{values}. The structure of an alist is:
2827 '((@var{key1} . @var{value1})
2828 (@var{key2} . @var{value2})
2829 (@var{key3} . @var{value3})
2833 If an alist is a grob property or @code{\paper} variable, its keys
2834 can be modified individually without affecting other keys.
2836 For example, to reduce the space between adjacent staves in a
2837 staff-group, use the @code{staff-staff-spacing} property of the
2838 @code{StaffGrouper} grob. The property is an alist with four
2839 keys: @code{basic-distance}, @code{minimum-distance},
2840 @code{padding}, and @code{stretchability}. The standard settings
2841 for this property are listed in the @qq{Backend} section of the
2842 Internals Reference (see @rinternals{StaffGrouper}):
2845 '((basic-distance . 9)
2846 (minimum-distance . 7)
2848 (stretchability . 5))
2851 One way to bring the staves closer together is by reducing the
2852 value of the @code{basic-distance} key (@code{9}) to match the
2853 value of @code{minimum-distance} (@code{7}). To modify a single
2854 key individually, use a @emph{nested declaration}:
2856 @lilypond[quote,verbatim]
2857 % default space between staves
2859 \new Staff { \clef treble c''1 }
2860 \new Staff { \clef bass c1 }
2863 % reduced space between staves
2864 \new PianoStaff \with {
2865 % this is the nested declaration
2866 \override StaffGrouper.staff-staff-spacing.basic-distance = #7
2868 \new Staff { \clef treble c''1 }
2869 \new Staff { \clef bass c1 }
2873 Using a nested declaration will update the specified key (such as
2874 @code{basic-distance} in the above example) without altering any
2875 other keys already set for the same property.
2877 Now suppose we want the staves to be as close as possible without
2878 overlapping. The simplest way to do this is to set all four alist
2879 keys to zero. However, it is not necessary to enter four nested
2880 declarations, one for each key. Instead, the property can be
2881 completely re-defined with one declaration, as an alist:
2883 @lilypond[quote,verbatim]
2884 \new PianoStaff \with {
2885 \override StaffGrouper.staff-staff-spacing =
2886 #'((basic-distance . 0)
2887 (minimum-distance . 0)
2889 (stretchability . 0))
2891 \new Staff { \clef treble c''1 }
2892 \new Staff { \clef bass c1 }
2896 Note that any keys not explicitly listed in the alist definition
2897 will be reset to their @emph{default-when-unset} values. In the
2898 case of @code{staff-staff-spacing}, any unset key-values would be
2899 reset to zero (except @code{stretchability}, which takes the value
2900 of @code{basic-distance} when unset). Thus the following two
2901 declarations are equivalent:
2904 \override StaffGrouper.staff-staff-spacing =
2905 #'((basic-distance . 7))
2907 \override StaffGrouper.staff-staff-spacing =
2908 #'((basic-distance . 7)
2909 (minimum-distance . 0)
2911 (stretchability . 7))
2914 One (possibly unintended) consequence of this is the removal of
2915 any standard settings that are set in an initialization file and
2916 loaded each time an input file is compiled. In the above example,
2917 the standard settings for @code{padding} and
2918 @code{minimum-distance} (defined in @file{scm/define-grobs.scm})
2919 are reset to their default-when-unset values (zero for both keys).
2920 Defining a property or variable as an alist (of any size) will
2921 always reset all unset key-values to their default-when-unset
2922 values. Unless this is the intended result, it is safer to update
2923 key-values individually with a nested declaration.
2925 @warning{Nested declarations will not work for context property
2926 alists (such as @code{beamExceptions}, @code{keyAlterations},
2927 @code{timeSignatureSettings}, etc.). These properties can only be
2928 modified by completely re-defining them as alists.}
2931 @node Useful concepts and properties
2932 @section Useful concepts and properties
2937 * Direction and placement::
2938 * Distances and measurements::
2940 * Staff symbol properties::
2942 * Visibility of objects::
2944 * Rotating objects::
2948 @subsection Input modes
2950 The way in which the notation contained within an input file is
2951 interpreted is determined by the current input mode. In general,
2952 there are two ways of specifying the mode: a long form, e.g.
2953 @code{\chordmode}, and a short form, e.g. @code{\chords}. The long
2954 form is typically used when supplying input to a variable or when
2955 entering input directly into an explicitly created context. The short
2956 form implicitly creates a context of the correct type for the input and
2957 passes the input directly to it. It is useful in simple situations
2958 when there is no requirement to explicitly create the receiving context.
2960 @subsubsubheading Chord mode
2962 This is activated with the @code{\chordmode} command, and causes
2963 input to be interpreted with the syntax of chord notation, see
2964 @ref{Chord notation}. Music in chord mode is rendered as chords on a staff
2965 when entered into a @code{Staff} context, as chord names when entered
2966 into a @code{ChordNames} context or as fret boards when entered into
2967 a @code{FretBoards} context.
2969 Chord mode is also activated with the @code{\chords} command. This
2970 also causes the following input to be interpreted with the syntax of
2971 chord notation but in addition it implicitly creates a new
2972 @code{ChordNames} context and renders the input into it as chord names,
2973 see @ref{Printing chord names}.
2975 @subsubsubheading Drum mode
2977 This is activated with the @code{\drummode} command, and causes
2978 input to be interpreted with the syntax of drum notation, see
2979 @ref{Basic percussion notation}. Music in drum mode is rendered as
2980 percussion notes when entered into a @code{DrumStaff} context.
2982 Drum mode is also activated with the @code{\drums} command. This
2983 also causes the following input to be interpreted with the syntax of
2984 drum notation but in addition it implicitly creates a new
2985 @code{DrumStaff} context and renders the input into it as percussion
2986 notes, see @ref{Basic percussion notation}.
2988 @subsubsubheading Figure mode
2990 This is activated with the @code{\figuremode} command, and causes
2991 input to be interpreted with the syntax of figured bass, see
2992 @ref{Entering figured bass}. Music in figure mode is rendered as
2993 figured bass when entered into a @code{FiguredBass} context or a
2994 @code{Staff} context.
2996 Figure mode is also activated with the @code{\figures} command.
2997 This also causes the following input to be interpreted with the
2998 figured bass syntax but in addition it implicitly creates a new
2999 @code{FiguredBass} context and renders the input into it as figured
3000 bass, see @ref{Introduction to figured bass}.
3002 @subsubsubheading Fret and tab modes
3004 There are no special input modes for entering fret and tab symbols.
3006 To create tab diagrams, enter notes or chords in note mode and
3007 render them in a @code{TabStaff} context, see
3008 @ref{Default tablatures}.
3010 To create fret diagrams above a staff, enter notes or chords in either
3011 note mode or chord mode and render them in a @code{FretBoards} context,
3012 see @ref{Automatic fret diagrams}. Alternatively, fret diagrams can be
3013 entered as markup above the notes using the @code{\fret-diagram}
3014 command, see @ref{Fret diagram markups}.
3016 @subsubsubheading Lyrics mode
3018 This is activated with the @code{\lyricmode} command, and causes
3019 input to be interpreted as lyric syllables with optional durations
3020 and associated lyric modifiers, see @ref{Vocal music}. Input in
3021 lyric mode is rendered as lyric syllables when entered into a
3022 @code{Lyrics} context.
3024 Lyric mode is also activated with the @code{\lyrics} command. This
3025 also causes the following input to be interpreted as lyric syllables
3026 but in addition it implicitly creates a new @code{Lyrics} context and
3027 renders the input into it as lyric syllables.
3029 Lyric mode is also activated with the @code{\addlyrics} command. This
3030 also implicitly creates a new @code{Lyrics} context and in addition it
3031 adds an implicit @code{\lyricsto} command which associates the following
3032 lyrics with the preceding music, see @ref{Automatic syllable durations}.
3034 @subsubsubheading Markup mode
3036 This is activated with the @code{\markup} command, and causes
3037 input to be interpreted with the syntax of markup, see
3038 @ref{Text markup commands}.
3040 @subsubsubheading Note mode
3042 This is the default mode or it may be activated with the
3043 @code{\notemode} command. Input is interpreted as pitches,
3044 durations, markup, etc and typeset as musical notation on a staff.
3046 It is not normally necessary to specify note mode explicitly, but
3047 it may be useful to do so in certain situations, for example if you
3048 are in lyric mode, chord mode or any other mode and want to insert
3049 something that only can be done with note mode syntax.
3052 @node Direction and placement
3053 @subsection Direction and placement
3055 In typesetting music the direction and placement of many items is
3056 a matter of choice. For example, the stems of notes can
3057 be directed up or down; lyrics, dynamics, and other expressive
3058 marks may be placed above or below the staff; text may be aligned
3059 left, right or center; etc. Most of these choices may be left to
3060 be determined automatically by LilyPond, but in some cases it may
3061 be desirable to force a particular direction or placement.
3064 * Articulation direction indicators::
3065 * The direction property::
3069 @node Articulation direction indicators
3070 @unnumberedsubsubsec Articulation direction indicators
3072 By default some directions are always up or always down (e.g.,
3073 dynamics or fermata), while other things can alternate between
3074 up or down based on the stem direction (like slurs or accents).
3076 @c TODO Add table showing these
3078 The default action may be overridden by prefixing the articulation
3079 by a @emph{direction indicator}. Three direction indicators are
3080 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
3081 and @code{-} (meaning @qq{use default direction}). The direction
3082 indicator can usually be omitted, in which case @code{-} is assumed,
3083 but a direction indicator is @strong{always} required before
3086 @item @code{\tweak} commands
3087 @item @code{\markup} commands
3088 @item @code{\tag} commands
3089 @item string markups, e.g., -"string"
3090 @item fingering instructions, e.g., @w{@code{-1}}
3091 @item articulation shortcuts, e.g., @w{@code{-.}}, @w{@code{->}}, @w{@code{--}}
3094 Direction indicators affect only the next note:
3096 @lilypond[verbatim,quote]
3106 @node The direction property
3107 @unnumberedsubsubsec The direction property
3109 The position or direction of many layout objects is controlled by the
3110 @code{direction} property.
3112 The value of the @code{direction} property may be set to @code{1},
3113 meaning @qq{up} or @qq{above}, or to @w{@code{-1}}, meaning @qq{down} or
3114 @qq{below}. The symbols @code{UP} and @code{DOWN} may be used instead
3115 of @code{1} and @w{@code{-1}} respectively. The default direction may
3116 be specified by setting @code{direction} to @code{0} or @code{CENTER}.
3117 Alternatively, in many cases predefined commands exist to specify the
3118 direction. These are of the form
3121 \xxxUp, \xxxDown or \xxxNeutral
3125 where @code{\xxxNeutral} means @qq{use the default} direction.
3126 See @rlearning{Within-staff objects}.
3128 In a few cases, arpeggio for example, the value of the @code{direction}
3129 property can specify whether the object is to be placed to the right or
3130 left of the parent. In this case @w{@code{-1}} or @code{LEFT} means
3131 @qq{to the left} and @code{1} or @code{RIGHT} means @qq{to the right}.
3132 @code{0} or @code{CENTER} means @qq{use the default} direction.
3135 These all have side-axis set to #X
3136 AmbitusAccidental - direction has no effect
3138 StanzaNumber - not tried
3139 TrillPitchAccidental - not tried
3140 TrillPitchGroup - not tried
3143 These indications affect all notes until they are canceled.
3145 @lilypond[verbatim,quote]
3156 In polyphonic music, it is generally better to specify an explicit
3157 @code{voice} than change an object's direction. For more information,
3158 see @ref{Multiple voices}.
3162 @rlearning{Within-staff objects}.
3165 @ref{Multiple voices}.
3168 @node Distances and measurements
3169 @subsection Distances and measurements
3171 @cindex distances, absolute
3172 @cindex distances, scaled
3179 Distances in LilyPond are of two types: absolute and scaled.
3181 Absolute distances are used for specifying margins, indents, and
3182 other page layout details, and are by default specified in
3183 millimeters. Distances may be specified in other units by
3184 following the quantity by @code{\mm}, @code{\cm},
3185 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27 of
3186 an inch). Page layout distances can also be specified in scalable
3187 units (see the following paragraph) by appending
3188 @code{\staff-space} to the quantity. Page layout is described in
3189 detail in @ref{Page layout}.
3191 Scaled distances are always specified in units of the staff-space
3192 or, rarely, the half staff-space. The staff-space is the distance
3193 between two adjacent staff lines. The default value can be changed
3194 globally by setting the global staff size, or it can be overridden
3195 locally by changing the @code{staff-space} property of
3196 @code{StaffSymbol}. Scaled distances automatically scale with any
3197 change to the either the global staff size or the
3198 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
3199 automatically only with changes to the global staff size.
3200 The global staff size thus enables the overall size of a rendered
3201 score to be easily varied. For the methods of setting the global
3202 staff size see @ref{Setting the staff size}.
3206 If just a section of a score needs to be rendered to a different
3207 scale, for example an ossia section or a footnote, the global staff
3208 size cannot simply be changed as this would affect the entire score.
3209 In such cases the change in size is made by overriding both the
3210 @code{staff-space} property of @code{StaffSymbol} and the size of
3211 the fonts. A Scheme function, @code{magstep}, is available to
3212 convert from a font size change to the equivalent change in
3213 @code{staff-space}. For an explanation and an example of its use,
3214 see @rlearning{Length and thickness of objects}.
3218 @rlearning{Length and thickness of objects}.
3222 @ref{Setting the staff size}.
3226 @subsection Dimensions
3229 @cindex bounding box
3231 The dimensions of a graphical object specify the positions of the left
3232 and right edges and the bottom and top edges of the objects' bounding
3233 box as distances from the objects' reference point in units of
3234 staff-spaces. These positions are usually coded as two Scheme pairs.
3235 For example, the text markup command @code{\with-dimensions} takes
3236 three arguments, the first two of which are a Scheme pair giving the
3237 left and right edge positions and a Scheme pair giving the bottom and
3241 \with-dimensions #'(-5 . 10) #'(-3 . 15) @var{arg}
3244 This specifies a bounding box for @var{arg} with its left edge at -5,
3245 its right edge at 10, its bottom edge at -3 and its top edge at 15,
3246 all measured from the objects' reference point in units of
3251 @ref{Distances and measurements}.
3254 @node Staff symbol properties
3255 @subsection Staff symbol properties
3257 @cindex adjusting staff symbol
3258 @cindex drawing staff symbol
3259 @cindex staff symbol, setting of
3261 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
3262 @c Need to think of uses for these properties. Eg 'line-positions
3263 @c is used in a snippet to thicken centre line.
3264 @c If retained, add @ref to here in 1.6.2 -td
3266 The vertical position of staff lines and the number of staff lines
3267 can be defined at the same time. As the following example shows,
3268 note positions are not influenced by the staff line positions.
3270 @warning{The @code{'line-positions} property overrides the
3271 @code{'line-count} property. The number of staff lines is
3272 implicitly defined by the number of elements in the list of values
3273 for @code{'line-positions}.}
3275 @lilypond[verbatim,quote]
3277 \override StaffSymbol.line-positions = #'(7 3 0 -4 -6 -7)
3279 \relative { a4 e' f b | d1 }
3282 The width of a staff can be modified. The units are staff
3283 spaces. The spacing of objects inside the staff is not affected by
3286 @lilypond[verbatim,quote]
3288 \override StaffSymbol.width = #23
3290 \relative { a4 e' f b | d1 }
3295 @subsection Spanners
3297 Many objects of musical notation extend over several notes or even
3298 several bars. Examples are slurs, beams, tuplet brackets, volta
3299 repeat brackets, crescendi, trills, and glissandi. Such objects
3300 are collectively called @qq{spanners}, and have special properties to control
3301 their appearance and behaviour. Some of these properties are common
3302 to all spanners; others are restricted to a sub-set of the spanners.
3304 All spanners support the @code{spanner-interface}. A few, essentially
3305 those that draw a straight line between the two objects, support in
3306 addition the @code{line-spanner-interface}.
3309 * Using the spanner-interface::
3310 * Using the line-spanner-interface::
3313 @node Using the spanner-interface
3314 @unnumberedsubsubsec Using the @code{spanner-interface}
3316 This interface provides two properties that apply to several spanners.
3318 @subsubsubheading The @code{minimum-length} property
3320 The minimum length of the spanner is specified by the
3321 @code{minimum-length} property. Increasing this usually has the
3322 necessary effect of increasing the spacing of the notes between the
3323 two end points. However, this override has no effect on
3324 many spanners, as their length is determined by other considerations.
3325 A few examples where it is effective are shown below.
3335 Works as long as callback is made:
3339 Works not at all for:
3348 @lilypond[verbatim,quote,fragment]
3351 % increase the length of the tie
3352 -\tweak minimum-length #5
3356 @lilypond[verbatim,quote]
3357 \relative \compressMMRests {
3360 % increase the length of the rest bar
3361 \once \override MultiMeasureRest.minimum-length = #20
3367 @lilypond[verbatim,quote]
3370 % increase the length of the hairpin
3371 \override Hairpin.minimum-length = #20
3376 This override can also be used to increase the length of slurs and
3379 @lilypond[verbatim,quote]
3383 -\tweak minimum-length #5
3388 -\tweak minimum-length #5
3393 For some layout objects, the @code{minimum-length} property becomes
3394 effective only if the @code{set-spacing-rods} procedure is called
3395 explicitly. To do this, the @code{springs-and-rods} property should
3396 be set to @code{ly:spanner::set-spacing-rods}. For example,
3397 the minimum length of a glissando has no effect unless the
3398 @code{springs-and-rods} property is set:
3400 @lilypond[verbatim,fragment,quote]
3404 % not effective alone
3405 \once \override Glissando.minimum-length = #20
3408 % effective only when both overrides are present
3409 \once \override Glissando.minimum-length = #20
3410 \once \override Glissando.springs-and-rods = #ly:spanner::set-spacing-rods
3414 The same is true of the @code{Beam} object:
3416 @lilypond[verbatim,fragment,quote]
3417 % not effective alone
3418 \once \override Beam.minimum-length = #20
3421 % effective only when both overrides are present
3422 \once \override Beam.minimum-length = #20
3423 \once \override Beam.springs-and-rods = #ly:spanner::set-spacing-rods
3427 @subsubsubheading The @code{to-barline} property
3429 The second useful property of the @code{spanner-interface} is
3430 @code{to-barline}. By default this is true, causing hairpins and
3431 other spanners which are terminated on the first note of a measure to
3432 end instead on the immediately preceding bar line. If set to false,
3433 the spanner will extend beyond the bar line and end on the note
3436 @lilypond[verbatim,quote]
3438 a' \< a a a a \! a a a \break
3439 \override Hairpin.to-barline = ##f
3440 a \< a a a a \! a a a
3444 This property is not effective for all spanners. For example,
3445 setting it to @code{#t} has no effect on slurs or phrasing slurs
3446 or on other spanners for which terminating on the bar line would
3449 @node Using the line-spanner-interface
3450 @unnumberedsubsubsec Using the @code{line-spanner-interface}
3452 Objects which support the @code{line-spanner-interface} include
3455 @item @code{DynamicTextSpanner}
3456 @item @code{Glissando}
3457 @item @code{TextSpanner}
3458 @item @code{TrillSpanner}
3459 @item @code{VoiceFollower}
3462 The routine responsible for drawing the stencils for these spanners is
3463 @code{ly:line-spanner::print}. This routine determines the
3464 exact location of the two end points and draws a line
3465 between them, in the style requested. The locations of the two
3466 end points of the spanner are computed on-the-fly, but it is
3467 possible to override their Y-coordinates. The
3468 properties which need to be specified are nested
3469 two levels down within the property hierarchy, but the syntax of
3470 the @code{\override} command is quite simple:
3472 @lilypond[quote,fragment,verbatim]
3474 \once \override Glissando.bound-details.left.Y = #3
3475 \once \override Glissando.bound-details.right.Y = #-2
3479 The units for the @code{Y} property are @code{staff-space}s,
3480 with the center line of the staff being the zero point.
3481 For the glissando, this is the value for @code{Y} at the
3482 X-coordinate corresponding to the center point of each note head,
3483 if the line is imagined to be extended to there.
3485 If @code{Y} is not set, the value is computed from the vertical
3486 position of the corresponding attachment point of the spanner.
3488 In case of a line break, the values for the end points are
3489 specified by the @code{left-broken} and @code{right-broken}
3490 sub-lists of @code{bound-details}. For example:
3492 @lilypond[ragged-right,fragment,verbatim,quote]
3493 \override Glissando.breakable = ##t
3494 \override Glissando.bound-details.right-broken.Y = #-3
3495 c''1 \glissando \break
3500 A number of further properties of the @code{left} and
3501 @code{right} sub-lists of the @code{bound-details} property
3502 may be modified in the same way as @code{Y}:
3506 This sets the Y-coordinate of the end point, in @code{staff-space}s
3507 offset from the staff center line. By default, it is the center of
3508 the bound object, so a glissando points to the vertical center of
3511 For horizontal spanners, such as text spanners and trill spanners,
3512 it is hardcoded to 0.
3515 This determines where the line starts and ends in the X-direction,
3516 relative to the bound object. So, a value of @w{@code{-1}} (or
3517 @code{LEFT}) makes the line start/end at the left side of the note
3518 head it is attached to.
3521 This is the absolute X-coordinate of the end point. It is usually
3522 computed on the fly, and overriding it has little useful effect.
3525 Line spanners may have symbols at the beginning or end, which is
3526 contained in this sub-property. This is for internal use; it is
3527 recommended that @code{text} be used instead.
3530 This is a markup that is evaluated to yield the stencil. It is used
3531 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
3533 @lilypond[quote,ragged-right,fragment,verbatim]
3534 \override TextSpanner.bound-details.left.text
3535 = \markup { \small \bold Slower }
3536 \relative { c''2\startTextSpan b c a\stopTextSpan }
3539 @item stencil-align-dir-y
3540 @item stencil-offset
3541 Without setting one of these, the stencil is simply put at the
3542 end-point, centered on the line, as defined by the @code{X} and
3543 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
3544 or @code{stencil-offset} will move the symbol at the edge vertically
3545 relative to the end point of the line:
3547 @lilypond[quote,fragment,verbatim]
3548 \override TextSpanner.bound-details.left.stencil-align-dir-y = #-2
3549 \override TextSpanner.bound-details.right.stencil-align-dir-y = #UP
3551 \override TextSpanner.bound-details.left.text = #"ggg"
3552 \override TextSpanner.bound-details.right.text = #"hhh"
3554 \relative { c'4^\startTextSpan c c c \stopTextSpan }
3557 Note that negative values move the text @emph{up}, contrary to the
3558 effect that might be expected, as a value of @w{@code{-1}} or
3559 @code{DOWN} means align the @emph{bottom} edge of the text with
3560 the spanner line. A value of @code{1} or @code{UP} aligns
3561 the top edge of the text with the spanner line.
3564 Setting this sub-property to @code{#t} produces an arrowhead at the
3565 end-points of the line.
3568 This sub-property controls the space between the specified
3569 end point of the line and the actual end. Without padding, a
3570 glissando would start and end in the center of each note head.
3574 The music function @code{\endSpanners} terminates the spanner
3575 which starts on the immediately following note prematurely. It
3576 is terminated after exactly one note, or at the following bar line
3577 if @code{to-barline} is true and a bar line occurs before the next
3580 @lilypond[verbatim,quote,ragged-right]
3583 c2 \startTextSpan c2 c2
3589 When using @code{\endSpanners} it is not necessary to close
3590 \startTextSpan with \stopTextSpan, nor is it necessary to close
3591 hairpins with @code{\!}.
3594 Internals Reference:
3595 @rinternals{TextSpanner},
3596 @rinternals{Glissando},
3597 @rinternals{VoiceFollower},
3598 @rinternals{TrillSpanner},
3599 @rinternals{line-spanner-interface}.
3602 @node Visibility of objects
3603 @subsection Visibility of objects
3605 @cindex objects, visibility of
3606 @cindex grobs, visibility of
3607 @cindex visibility of objects
3609 There are four main ways in which the visibility of layout objects
3610 can be controlled: their stencil can be removed, they can be made
3611 transparent, they can be colored white, or their
3612 @code{break-visibility} property can be overridden. The first
3613 three apply to all layout objects; the last to just a few -- the
3614 @emph{breakable} objects. The Learning Manual introduces these
3615 four techniques, see @rlearning{Visibility and color of objects}.
3617 There are also a few other techniques which are specific to
3618 certain layout objects. These are covered under Special
3622 * Removing the stencil::
3623 * Making objects transparent::
3624 * Painting objects white::
3625 * Using break-visibility::
3626 * Special considerations::
3630 @node Removing the stencil
3631 @unnumberedsubsubsec Removing the stencil
3633 @cindex stencil, removing
3636 Every layout object has a stencil property. By default this is set
3637 to the specific function which draws that object. If this property
3638 is overridden to @code{#f} no function will be called and the object
3639 will not be drawn. The default action can be recovered with
3642 @lilypond[quote,fragment,verbatim]
3644 \override Score.BarLine.stencil = ##f
3646 \revert Score.BarLine.stencil
3650 This rather common operation has a shortcut @code{\omit}:
3652 @lilypond[quote,fragment,verbatim]
3656 \undo \omit Score.BarLine
3660 @node Making objects transparent
3661 @unnumberedsubsubsec Making objects transparent
3663 @cindex transparent, making objects
3666 Every layout object has a transparent property which by default is
3667 set to @code{#f}. If set to @code{#t} the object still occupies
3668 space but is made invisible.
3670 @lilypond[quote,fragment,verbatim]
3672 \once \override NoteHead.transparent = ##t
3676 This rather common operation has a shortcut @code{\hide}:
3678 @lilypond[quote,fragment,verbatim]
3680 \once \hide NoteHead
3684 @node Painting objects white
3685 @unnumberedsubsubsec Painting objects white
3687 @cindex objects, coloring
3688 @cindex coloring objects
3690 @cindex printing order
3691 @cindex overwriting objects
3692 @cindex objects, overwriting
3693 @cindex grobs, overwriting
3695 Every layout object has a color property which by default is set
3696 to @code{black}. If this is overridden to @code{white} the object
3697 will be indistinguishable from the white background. However,
3698 if the object crosses other objects the color of the crossing
3699 points will be determined by the order in which they are drawn,
3700 and this may leave a ghostly image of the white object, as shown
3703 @lilypond[quote,fragment,verbatim]
3704 \override Staff.Clef.color = #white
3708 This may be avoided by changing the order of printing the objects.
3709 All layout objects have a @code{layer} property which should be set
3710 to an integer. Objects with the lowest value of @code{layer} are
3711 drawn first, then objects with progressively higher values are drawn,
3712 so objects with higher values overwrite objects with lower values.
3713 By default most objects are assigned a @code{layer} value of
3714 @code{1}, although a few objects, including @code{StaffSymbol} and
3715 @code{BarLine}, are assigned a value of @code{0}. The order of
3716 printing objects with the same value of @code{layer} is indeterminate.
3718 In the example above the white clef, with a default @code{layer}
3719 value of @code{1}, is drawn after the staff lines (default
3720 @code{layer} value @code{0}), so overwriting them. To change this,
3721 the @code{Clef} object must be given in a lower value of
3722 @code{layer}, say @w{@code{-1}}, so that it is drawn earlier:
3724 @lilypond[quote,fragment,verbatim]
3725 \override Staff.Clef.color = #white
3726 \override Staff.Clef.layer = #-1
3730 @node Using break-visibility
3731 @unnumberedsubsubsec Using break-visibility
3733 @c TODO Add making other objects breakable
3735 @cindex break-visibility
3737 Most layout objects are printed only once, but some like
3738 bar lines, clefs, time signatures and key signatures, may need
3739 to be printed twice when a line break occurs -- once at the end
3740 of the line and again at the start of the next line. Such
3741 objects are called @emph{breakable}, and have a property, the
3742 @code{break-visibility} property to control their visibility
3743 at the three positions in which they may appear -- at the
3744 start of a line, within a line if they are changed, and at the
3745 end of a line if a change takes place there.
3747 For example, the time signature
3748 by default will be printed at the start of the first line, but
3749 nowhere else unless it changes, when it will be printed at the
3750 point at which the change occurs. If this change occurs at the
3751 end of a line the new time signature will be printed at the start
3752 of the next line and a cautionary time signature will be printed
3753 at the end of the previous line as well.
3755 This behaviour is controlled by the @code{break-visibility}
3756 property, which is explained in
3757 @c Leave this ref on a newline - formats incorrectly otherwise -td
3758 @rlearning{Visibility and color of objects}. This property takes
3759 a vector of three booleans which, in order, determine whether the
3760 object is printed at the end of, within the body of, or at the
3761 beginning of a line. Or to be more precise, before a line break,
3762 where there is no line break, or after a line break.
3764 Alternatively, these eight combinations may be specified
3765 by pre-defined functions, defined in @file{scm/output-lib.scm},
3766 where the last three columns indicate whether the layout objects
3767 will be visible in the positions shown at the head of the columns:
3769 @multitable {@code{begin-of-line-invisible}} {@code{#(#t #t #t)}} {Before} {At no} {After}
3770 @headitem Function @tab Vector @tab Before @tab At no @tab After
3771 @headitem form @tab form @tab break @tab break @tab break
3773 @item @code{all-visible} @tab @code{#(#t #t #t)} @tab yes @tab yes @tab yes
3774 @item @code{begin-of-line-visible} @tab @code{#(#f #f #t)} @tab no @tab no @tab yes
3775 @item @code{center-visible} @tab @code{#(#f #t #f)} @tab no @tab yes @tab no
3776 @item @code{end-of-line-visible} @tab @code{#(#t #f #f)} @tab yes @tab no @tab no
3777 @item @code{begin-of-line-invisible} @tab @code{#(#t #t #f)} @tab yes @tab yes @tab no
3778 @item @code{center-invisible} @tab @code{#(#t #f #t)} @tab yes @tab no @tab yes
3779 @item @code{end-of-line-invisible} @tab @code{#(#f #t #t)} @tab no @tab yes @tab yes
3780 @item @code{all-invisible} @tab @code{#(#f #f #f)} @tab no @tab no @tab no
3783 The default settings of @code{break-visibility} depend on the
3784 layout object. The following table shows all the layout objects
3785 of interest which are affected by @code{break-visibility} and the
3786 default setting of this property:
3788 @multitable @columnfractions .3 .3 .4
3790 @headitem Layout object @tab Usual context @tab Default setting
3792 @c omit Ambitus as it appears not to be affected by break-visibility -td
3793 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
3794 @item @code{BarLine} @tab @code{Score} @tab calculated
3795 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
3796 @c omit the following item until it can be explained -td
3797 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
3798 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
3799 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
3800 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
3801 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
3802 @item @code{KeyCancellation} @tab @code{Staff} @tab @code{begin-of-line-invisible}
3803 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
3804 @c omit LeftEdge until it can be explained -td
3805 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
3806 @item @code{ClefModifier} @tab @code{Staff} @tab @code{begin-of-line-visible}
3807 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
3808 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
3812 The example below shows the use of the vector form to control the
3813 visibility of bar lines:
3815 @lilypond[quote,verbatim,ragged-right]
3819 % Remove bar line at the end of the current line
3820 \once \override Score.BarLine.break-visibility = ##(#f #t #t)
3827 Although all three components of the vector used to override
3828 @code{break-visibility} must be present, not all of them are
3829 effective with every layout object, and some combinations may
3830 even give errors. The following limitations apply:
3833 @item Bar lines cannot be printed at the start of line.
3835 @item A bar number cannot be printed at the start of the @emph{first}
3836 line unless it is set to be different from @code{1}.
3838 @item Clef -- see the next section.
3840 @item Double percent repeats are either @emph{all printed} or
3841 @emph{all suppressed}. Use @code{begin-of-line-invisible}
3842 to print them and @code{all-invisible} to suppress them.
3844 @item Key signature -- see the next section.
3846 @item ClefModifier -- see the next section.
3850 @node Special considerations
3851 @unnumberedsubsubsec Special considerations
3853 @subsubsubheading Visibility following explicit changes
3855 @cindex key signature, visibility following explicit change
3856 @cindex explicitKeySignatureVisibility
3857 @cindex clef, visibility following explicit change
3858 @cindex explicitClefVisibility
3860 The @code{break-visibility} property controls the visibility of
3861 key signatures and changes of clef only at the start of lines,
3862 i.e., after a break. It has no effect on the visibility of the
3863 key signature or clef following an explicit key change or an
3864 explicit clef change within or at the end of a line. In the
3865 following example the key signature following the explicit change
3866 to B-flat major is still visible, even though @code{all-invisible}
3869 @lilypond[quote,verbatim,ragged-right]
3873 % Try to remove all key signatures
3874 \override Staff.KeySignature.break-visibility = #all-invisible
3883 The visibility of such explicit key signature and clef changes is
3884 controlled by the @code{explicitKeySignatureVisibility} and
3885 @code{explicitClefVisibility} properties. These are the equivalent
3886 of the @code{break-visibility} property and both take a vector of
3887 three booleans or the predefined functions listed above, exactly like
3888 @code{break-visibility}. Both are properties of the Staff context,
3889 not the layout objects themselves, and so they are set using the
3890 @code{\set} command. Both are set by default to @code{all-visible}.
3891 These properties control only the visibility of key signatures and
3892 clefs resulting from explicit changes and do not affect key
3893 signatures and clefs at the beginning of lines;
3894 @code{break-visibility} must still be overridden in the appropriate
3895 object to remove these.
3897 @lilypond[quote,verbatim,ragged-right]
3901 \set Staff.explicitKeySignatureVisibility = #all-invisible
3902 \override Staff.KeySignature.break-visibility = #all-invisible
3910 @subsubsubheading Visibility of cancelling accidentals
3912 To remove the cancelling accidentals printed at an explicit key
3913 change, set the Staff context property @code{printKeyCancellation}
3916 @lilypond[quote,verbatim,ragged-right]
3920 \set Staff.explicitKeySignatureVisibility = #all-invisible
3921 \set Staff.printKeyCancellation = ##f
3922 \override Staff.KeySignature.break-visibility = #all-invisible
3930 With these overrides only the accidentals before the notes remain
3931 to indicate the change of key.
3933 Note that when changing the key to C@tie{}major or A@tie{}minor
3934 the cancelling accidentals would be the @emph{only} indication of
3935 the key change. In this case setting @code{printKeyCancellation} to
3936 @code{#f} has no effect:
3938 @lilypond[quote,verbatim,ragged-right]
3942 \set Staff.explicitKeySignatureVisibility = #all-invisible
3943 \set Staff.printKeyCancellation = ##f
3951 To suppress the cancelling accidentals even when the key is
3952 changed to C@tie{}major or A@tie{}minor, override
3953 the visibility of the @code{KeyCancellation} grob instead:
3955 @lilypond[quote,verbatim,ragged-right]
3959 \set Staff.explicitKeySignatureVisibility = #all-invisible
3960 \override Staff.KeyCancellation.break-visibility = #all-invisible
3968 @c TODO Add visibility of cautionary accidentals before notes
3970 @subsubsubheading Automatic bars
3972 @cindex automaticBars
3973 @cindex bar lines, suppressing
3975 As a special case, the printing of bar lines can also be turned off
3976 by setting the @code{automaticBars} property in the Score context.
3977 If set to @code{#f}, bar lines will not be printed automatically;
3978 they must be explicitly created with a @code{\bar} command. Unlike
3979 the @code{\cadenzaOn} predefined command, measures are still counted.
3980 Bar generation will resume according to that count if this property
3981 is later set to @code{#t}. When set to @code{#f}, line breaks can
3982 occur only at explicit @code{\bar} commands.
3986 @subsubsubheading Transposed clefs
3988 @cindex transposed clefs, visibility of
3989 @cindex visibility of transposed clefs
3990 @cindex clefs, visibility of transposition
3992 The small transposition symbol on transposed clefs is produced by the
3993 @code{ClefModifier} layout object. Its visibility is automatically
3994 inherited from the @code{Clef} object, so it is not necessary to apply
3995 any required @code{break-visibility} overrides to the @code{ClefModifier}
3996 layout objects to suppress transposition symbols for invisible clefs.
3998 For explicit clef changes, the @code{explicitClefVisibility}
3999 property controls both the clef symbol and any transposition symbol
4004 @rlearning{Visibility and color of objects}.
4008 @subsection Line styles
4010 Some performance indications, e.g., @i{rallentando} and
4011 @i{accelerando} and @i{trills} are written as text and are
4012 extended over many measures with lines, sometimes dotted or wavy.
4014 These all use the same routines as the glissando for drawing the
4015 texts and the lines, and tuning their behavior is therefore also
4016 done in the same way. It is done with a spanner, and the routine
4017 responsible for drawing the spanners is
4018 @code{ly:line-spanner::print}. This routine determines the
4019 exact location of the two @i{span points} and draws a line
4020 between them, in the style requested.
4022 Here is an example showing the different line styles available,
4023 and how to tune them.
4025 @lilypond[ragged-right,verbatim,quote]
4028 \once \override Glissando.style = #'dashed-line
4030 \override Glissando.style = #'dotted-line
4032 \override Glissando.style = #'zigzag
4034 \override Glissando.style = #'trill
4039 The locations of the end-points of the spanner are computed
4040 on-the-fly for every graphic object, but it is possible to
4044 @lilypond[ragged-right,verbatim,quote]
4047 \once \override Glissando.bound-details.right.Y = #-2
4052 The value for @code{Y} is set to @w{@code{-2}} for the right end
4053 point. The left side may be similarly adjusted by specifying
4054 @code{left} instead of @code{right}.
4056 If @code{Y} is not set, the value is computed from the vertical
4057 position of the left and right attachment points of the spanner.
4059 Other adjustments of spanners are possible, for details, see
4062 @node Rotating objects
4063 @subsection Rotating objects
4065 Both layout objects and elements of markup text can be rotated by
4066 any angle about any point, but the method of doing so differs.
4069 * Rotating layout objects::
4073 @node Rotating layout objects
4074 @unnumberedsubsubsec Rotating layout objects
4076 @cindex rotating objects
4077 @cindex objects, rotating
4079 All layout objects which support the @code{grob-interface} can be
4080 rotated by setting their @code{rotation} property. This takes a
4081 list of three items: the angle of rotation counter-clockwise,
4082 and the x and y coordinates of the point relative to the object's
4083 reference point about which the rotation is to be performed. The
4084 angle of rotation is specified in degrees and the coordinates in
4087 The angle of rotation and the coordinates of the rotation point must
4088 be determined by trial and error.
4090 @cindex hairpins, angled
4091 @cindex angled hairpins
4093 There are only a few situations where the rotation of layout
4094 objects is useful; the following example shows one situation where
4097 @lilypond[quote,fragment,verbatim]
4099 \override Hairpin.rotation = #'(20 -1 0)
4103 @node Rotating markup
4104 @unnumberedsubsubsec Rotating markup
4106 All markup text can be rotated to lie at any angle by prefixing it
4107 with the @code{\rotate} command. The command takes two arguments:
4108 the angle of rotation in degrees counter-clockwise and the text to
4109 be rotated. The extents of the text are not rotated: they take
4110 their values from the extremes of the x and y coordinates of the
4111 rotated text. In the following example the
4112 @code{outside-staff-priority} property for text is set to @code{#f}
4113 to disable the automatic collision avoidance, which would push some
4114 of the text too high.
4116 @lilypond[quote,fragment,verbatim]
4117 \override TextScript.outside-staff-priority = ##f
4118 g4^\markup { \rotate #30 "a G" }
4119 b^\markup { \rotate #30 "a B" }
4120 des'^\markup { \rotate #30 "a D-Flat" }
4121 fis'^\markup { \rotate #30 "an F-Sharp" }
4124 @node Advanced tweaks
4125 @section Advanced tweaks
4127 This section discusses various approaches to fine tuning the
4128 appearance of the printed score.
4131 * Aligning objects::
4132 * Vertical grouping of grobs::
4133 * Modifying stencils::
4134 * Modifying shapes::
4135 * Modifying broken spanners::
4136 * Unpure-pure containers::
4141 @rlearning{Tweaking output},
4142 @rlearning{Other sources of information}.
4145 @ref{Explaining the Internals Reference},
4146 @ref{Modifying properties}.
4149 @rextend{Interfaces for programmers}.
4152 @file{scm/define-grobs.scm}.
4155 @rlsr{Tweaks and overrides}.
4157 Internals Reference:
4158 @rinternals{All layout objects}.
4161 @node Aligning objects
4162 @subsection Aligning objects
4164 Graphical objects which support the @code{self-alignment-interface}
4165 and/or the @code{side-position-interface} can be aligned to a previously
4166 placed object in a variety of ways. For a list of these objects, see
4167 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
4169 All graphical objects have a reference point, a horizontal extent and a
4170 vertical extent. The horizontal extent is a pair of numbers
4171 giving the displacements from the reference point of the left and
4172 right edges, displacements to the left being negative. The vertical
4173 extent is a pair of numbers giving the displacement from the reference
4174 point to the bottom and top edges, displacements down being negative.
4176 An object's position on a staff is given by the values of the
4177 @code{X-offset} and @code{Y-offset} properties. The value of
4178 @code{X-offset} gives the displacement from the X coordinate of
4179 the reference point of the parent object, and the value of
4180 @code{Y-offset} gives the displacement from the center line of the
4181 staff. The values of @code{X-offset} and @code{Y-offset} may
4182 be set directly or may be set to be calculated by procedures in order
4183 to achieve alignment with the parent object.
4185 @warning{Many objects have special positioning considerations which
4186 cause any setting of @code{X-offset} or @code{Y-offset} to be
4187 ignored or modified, even though the object supports the
4188 @code{self-alignment-interface}. Overriding the @code{X-offset}
4189 or @code{Y-offset} properties to a fixed value causes the respective
4190 @code{self-alignment} property to be disregarded.}
4192 For example, an accidental can be repositioned vertically by setting
4193 @code{Y-offset} but any changes to @code{X-offset} have no effect.
4195 Rehearsal marks may be aligned with breakable objects such as bar
4196 lines, clef symbols, time signature symbols and key signatures. There
4197 are special properties to be found in the @code{break-aligned-interface}
4198 for positioning rehearsal marks on such objects.
4202 @ref{Using the break-alignable-interface}.
4205 @rextend{Callback functions}.
4208 * Setting X-offset and Y-offset directly::
4209 * Using the side-position-interface::
4210 * Using the self-alignment-interface::
4211 * Using the break-alignable-interface::
4214 @node Setting X-offset and Y-offset directly
4215 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
4217 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
4218 properties of many objects. The following example shows three
4219 notes with the default fingering position and the positions with @code{X-offset}
4220 and @code{Y-offset} modified.
4222 @lilypond[verbatim,fragment,quote]
4229 -\tweak X-offset #-1
4236 @node Using the side-position-interface
4237 @unnumberedsubsubsec Using the @code{side-position-interface}
4239 An object which supports the @code{side-position-interface} can be
4240 placed next to its parent object so that
4241 the specified edges of the two objects touch. The object may be
4242 placed above, below, to the right or to the left of the parent.
4243 The parent cannot be specified; it is determined by the order of
4244 elements in the input stream. Most objects have the associated
4245 note head as their parent.
4247 The values of the @code{side-axis} and @code{direction} properties
4248 determine where the object is to be placed, as follows:
4250 @c TODO add an example of each to the table
4252 @multitable @columnfractions .3 .3 .3
4253 @headitem @code{side-axis} @tab @code{direction} @tab
4254 @headitem property @tab property @tab Placement
4256 @item @code{0} @tab @code{-1} @tab left
4257 @item @code{0} @tab @code{1} @tab right
4258 @item @code{1} @tab @code{-1} @tab below
4259 @item @code{1} @tab @code{1} @tab above
4263 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
4264 the procedure @code{ly:side-position-interface::x-aligned-side}.
4265 This procedure will return the correct value of @code{X-offset} to
4266 place the object to the left or right side of the parent according
4267 to value of @code{direction}.
4269 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
4270 the procedure @code{ly:side-position-interface::y-aligned-side}.
4271 This procedure will return the correct value of @code{Y-offset} to
4272 place the object to the top or bottom of the parent according
4273 to value of @code{direction}.
4275 @c TODO Add examples
4277 @node Using the self-alignment-interface
4278 @unnumberedsubsubsec Using the @code{self-alignment-interface}
4280 @subsubsubheading Self-aligning objects horizontally
4282 The horizontal alignment of an object which supports the
4283 @code{self-alignment-interface} is controlled by the value of
4284 the @code{self-alignment-X} property, provided the object's
4285 @code{X-offset} property is set to
4286 @code{ly:self-alignment-interface::x-aligned-on-self}.
4287 @code{self-alignment-X} may be given any
4288 real value, in units of half the total X extent of the
4289 object. Negative values move the object to the right, positive
4290 to the left. A value of @code{0} centers the object on the
4291 reference point of its parent, a value of @w{@code{-1}} aligns the
4292 left edge of the object on the reference point of its parent,
4293 and a value of @code{1} aligns the right edge of the object on the
4294 reference point of its parent. The symbols @code{LEFT},
4295 @code{CENTER}, and @code{RIGHT} may be used instead of the values
4296 @w{@code{-1}}, @code{0}, and @code{1}, respectively.
4298 Normally the @code{\override} command would be used to modify the
4299 value of @code{self-alignment-X}, but the @code{\tweak} command
4300 can be used to separately align several annotations on a single
4303 @lilypond[quote,verbatim,fragment]
4305 -\tweak self-alignment-X #-1
4307 -\tweak self-alignment-X #0
4309 -\tweak self-alignment-X #RIGHT
4311 -\tweak self-alignment-X #-2.5
4312 ^"aligned further to the right"
4315 @subsubsubheading Self-aligning objects vertically
4317 Objects may be aligned vertically in an analogous way to aligning
4318 them horizontally if the @code{Y-offset} property is set to
4319 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
4320 other mechanisms are often involved in vertical alignment: the
4321 value of @code{Y-offset} is just one variable taken into account.
4322 This may make adjusting the value of some objects tricky.
4323 The units are just half the vertical extent of the object, which
4324 is usually quite small, so quite large numbers may be required.
4325 A value of @w{@code{-1}} aligns the lower edge of the object with
4326 the reference point of the parent object, a value of @code{0}
4327 aligns the center of the object with the reference point of the
4328 parent, and a value of @code{1} aligns the top edge of the object
4329 with the reference point of the parent. The symbols @code{DOWN},
4330 @code{CENTER}, and @code{UP} may be substituted for @w{@code{-1}},
4331 @code{0}, and @code{1}, respectively.
4333 @subsubsubheading Self-aligning objects in both directions
4335 By setting both @code{X-offset} and @code{Y-offset}, an object may
4336 be aligned in both directions simultaneously.
4338 The following example shows how to adjust a fingering mark so
4339 that it nestles close to the note head.
4341 @lilypond[quote,verbatim,fragment]
4343 -\tweak self-alignment-X #0.5 % move horizontally left
4344 -\tweak Y-offset #ly:self-alignment-interface::y-aligned-on-self
4345 -\tweak self-alignment-Y #-1 % move vertically up
4350 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
4352 @c Cannot document as they do not seem to operate consistently on all objects -td
4353 @c TODO investigate further
4355 The @code{aligned-on-parent} procedures are used in the same way
4356 as the @code{aligned-on-self} procedures, they difference being
4357 that they permit an object to be aligned with the @emph{edges} of
4358 the parent rather than the parent's reference point. The following
4359 example shows the difference:
4363 @lilypond[verbatim,quote]
4369 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
4371 @c Cannot document as they do not seem to operate consistently on all objects -td
4372 @c TODO investigate further
4376 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
4378 @node Using the break-alignable-interface
4379 @unnumberedsubsubsec Using the @code{break-alignable-interface}
4381 @cindex align to objects
4382 @cindex break-align-symbols
4384 Rehearsal marks and bar numbers may be aligned with notation
4385 objects other than bar lines. These objects include @code{ambitus},
4386 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
4387 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
4388 @code{time-signature}.
4390 Each type of object has its own default reference point, to which
4391 rehearsal marks are aligned:
4393 @lilypond[verbatim,quote,fragment]
4394 % The rehearsal mark will be aligned to the right edge of the Clef
4395 \override Score.RehearsalMark.break-align-symbols = #'(clef)
4400 % The rehearsal mark will be aligned to the left edge of the Time Signature
4401 \override Score.RehearsalMark.break-align-symbols = #'(time-signature)
4407 % The rehearsal mark will be centered above the Breath Mark
4408 \override Score.RehearsalMark.break-align-symbols = #'(breathing-sign)
4417 A list of possible target alignment objects may be specified. If
4418 some of the objects are invisible at that point due to the setting
4419 of @code{break-visibility} or the explicit visibility settings for
4420 keys and clefs, the rehearsal mark or bar number is aligned to the
4421 first object in the list which is visible. If no objects in the
4422 list are visible the object is aligned to the bar line. If the bar
4423 line is invisible the object is aligned to the place where the bar
4426 @lilypond[verbatim,quote,fragment]
4427 % The rehearsal mark will be aligned to the right edge of the Key Signature
4428 \override Score.RehearsalMark.break-align-symbols = #'(key-signature clef)
4433 % The rehearsal mark will be aligned to the right edge of the Clef
4434 \set Staff.explicitKeySignatureVisibility = #all-invisible
4435 \override Score.RehearsalMark.break-align-symbols = #'(key-signature clef)
4440 % The rehearsal mark will be centered above the Bar Line
4441 \set Staff.explicitKeySignatureVisibility = #all-invisible
4442 \set Staff.explicitClefVisibility = #all-invisible
4443 \override Score.RehearsalMark.break-align-symbols = #'(key-signature clef)
4450 The alignment of the rehearsal mark relative to the notation object
4451 can be changed, as shown in the following example. In a score with
4452 multiple staves, this setting should be done for all the staves.
4454 @lilypond[verbatim,quote,fragment]
4455 % The RehearsalMark will be aligned with the right edge of the Key Signature
4456 \override Score.RehearsalMark.break-align-symbols = #'(key-signature)
4462 % The RehearsalMark will be centered above the Key Signature
4463 \once \override Score.KeySignature.break-align-anchor-alignment = #CENTER
4467 % The RehearsalMark will be aligned with the left edge of the Key Signature
4468 \once \override Score.KeySignature.break-align-anchor-alignment = #LEFT
4474 The rehearsal mark can also be offset to the right or left of the left
4475 edge by an arbitrary amount. The units are staff-spaces:
4477 @lilypond[verbatim,quote,fragment]
4478 % The RehearsalMark will be aligned with the left edge of the Key Signature
4479 % and then shifted right by 3.5 staff-spaces
4480 \override Score.RehearsalMark.break-align-symbols = #'(key-signature)
4481 \once \override Score.KeySignature.break-align-anchor = #3.5
4485 % The RehearsalMark will be aligned with the left edge of the Key Signature
4486 % and then shifted left by 2 staff-spaces
4487 \once \override Score.KeySignature.break-align-anchor = #-2
4494 @node Vertical grouping of grobs
4495 @subsection Vertical grouping of grobs
4497 @c TODO Expand this section
4499 The VerticalAlignment and VerticalAxisGroup grobs work together.
4500 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
4501 etc. VerticalAlignment then vertically aligns the different grobs
4502 grouped together by VerticalAxisGroup. There is usually only one
4503 VerticalAlignment per score but every Staff, Lyrics, etc., has its own
4507 @node Modifying stencils
4508 @subsection Modifying stencils
4510 All layout objects have a @code{stencil} property which is part of
4511 the @code{grob-interface}. By default, this property is usually
4512 set to a function specific to the object that is tailor-made to
4513 render the symbol which represents it in the output. For example,
4514 the standard setting for the @code{stencil} property of the
4515 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
4517 The standard symbol for any object can be replaced by modifying the
4518 @code{stencil} property to reference a different, specially-written,
4519 procedure. This requires a high level of knowledge of the internal
4520 workings of LilyPond, but there is an easier way which can often
4521 produce adequate results.
4523 This is to set the @code{stencil} property to the procedure which
4524 prints text -- @code{ly:text-interface::print} -- and to add a
4525 @code{text} property to the object which is set to contain the
4526 markup text which produces the required symbol. Due to the
4527 flexibility of markup, much can be achieved -- see in particular
4528 @ref{Graphic notation inside markup}.
4530 The following example demonstrates this by changing the note head
4531 symbol to a cross within a circle.
4533 @lilypond[verbatim,quote]
4535 \once \override NoteHead.stencil = #ly:text-interface::print
4536 \once \override NoteHead.text = \markup {
4538 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
4539 \musicglyph #"noteheads.s2cross"
4547 Any of the @emph{Feta} glyphs used in the Emmentaler font can be
4548 supplied to the @code{\musicglyph} markup command -- see
4549 @ref{The Emmentaler font}.
4551 @file{EPS} files and Postscript commands can both be inserted inline
4552 using the @code{\epsfile} and @code{\postscript} markup commands
4553 respectively -- see @ref{Graphic}.
4558 @ref{Graphic notation inside markup},
4559 @ref{Formatting text},
4560 @ref{Text markup commands},
4561 @ref{The Emmentaler font},
4565 @node Modifying shapes
4566 @subsection Modifying shapes
4569 * Modifying ties and slurs::
4572 @node Modifying ties and slurs
4573 @unnumberedsubsubsec Modifying ties and slurs
4575 @cindex slurs, modifying
4576 @cindex ties, modifying
4577 @cindex Bézier curves, control points
4578 @cindex control points, Bézier curves
4580 @code{Tie}s, @code{Slur}s, @code{PhrasingSlur}s,
4581 @code{LaissezVibrerTie}s and @code{RepeatTie}s are all drawn as
4582 third-order Bézier curves. If the shape of the tie or slur which
4583 is calculated automatically is not optimum, the shape may be
4584 modified manually in two ways:
4588 by specifying the displacements to be made to the control points
4589 of the automatically calculated Bézier curve, or
4592 by explicitly specifying the positions of the four control points
4593 required to define the wanted curve.
4596 Both methods are explained below. The first method is more suitable
4597 if only slight adjustments to the curve are required; the second may
4598 be better for creating curves which are related to just a single
4601 @subsubsubheading Cubic Bézier curves
4603 Third-order or cubic Bézier curves are defined by four control
4604 points. The first and fourth control points are precisely the
4605 starting and ending points of the curve. The intermediate two
4606 control points define the shape. Animations showing how the curve
4607 is drawn can be found on the web, but the following description
4608 may be helpful. The curve starts from the first control point
4609 heading directly towards the second, gradually bending over to
4610 head towards the third and continuing to bend over to head towards
4611 the fourth, arriving there travelling directly from the third
4612 control point. The curve is entirely contained in the
4613 quadrilateral defined by the four control points. Translations,
4614 rotations and scaling of the control points all result in exactly
4615 the same operations on the curve.
4617 @subsubsubheading Specifying displacements from current control points
4619 @cindex shaping slurs and ties
4622 In this example the automatic placement of the tie is not optimum,
4623 and @code{\tieDown} would not help.
4625 @lilypond[verbatim,quote]
4629 \relative { r4 <g' c,> <g c,> <g c,> }
4633 Adjusting the control points of the tie with @code{\shape} allows
4634 the collisions to be avoided.
4636 The syntax of @code{\shape} is
4639 [-]\shape @var{displacements} @var{item}
4642 This will reposition the control-points of @var{item} by the amounts
4643 given by @var{displacements}. The @var{displacements} argument is a
4644 list of number pairs or a list of such lists. Each element of a pair
4645 represents the displacement of one of the coordinates of a
4646 control-point. If @var{item} is a string, the result is
4647 @code{\once\override} for the specified grob type. If @var{item} is
4648 a music expression, the result is the same music expression with an
4649 appropriate tweak applied.
4651 In other words, the @code{\shape} function can act as either a
4652 @code{\once\override} command or a @code{\tweak} command depending
4653 on whether the @var{item} argument is a grob name, like @qq{Slur},
4654 or a music expression, like @qq{(}. The @var{displacements} argument
4655 specifies the displacements of the four control points as a list of
4656 four pairs of (dx . dy) values in units of staff-spaces (or a list
4657 of such lists if the curve has more than one segment).
4659 The leading hyphen is required if and only if the @code{\tweak} form
4662 So, using the same example as above and the @code{\once\override}
4663 form of @code{\shape}, this will raise the tie by half a staff-space:
4665 @lilypond[verbatim,quote]
4668 \shape #'((0 . 0.5) (0 . 0.5) (0 . 0.5) (0 . 0.5)) Tie
4672 \relative { r4 <g' c,> <g c,> <g c,> }
4676 This positioning of the tie is better, but maybe it should be raised
4677 more in the center. The following example does this, this time using
4678 the alternative @code{\tweak} form:
4680 @lilypond[verbatim,quote]
4683 e'1-\shape #'((0 . 0.5) (0 . 1) (0 . 1) (0 . 0.5)) ~ e'
4686 \relative { r4 <g' c,> <g c,> <g c,> }
4690 Changes to the horizontal positions of the control points may be made
4691 in the same way, and two different curves starting at the same
4692 musical moment may also be shaped:
4694 @lilypond[verbatim,quote,ragged-right]
4696 c''8(\( a) a'4 e c\)
4697 \shape #'((0.7 . -0.4) (0.5 . -0.4) (0.3 . -0.3) (0 . -0.2)) Slur
4698 \shape #'((0 . 0) (0 . 0.5) (0 . 0.5) (0 . 0)) PhrasingSlur
4703 The @code{\shape} function can also displace the control points of
4704 curves which stretch across line breaks. Each piece of the broken
4705 curve can be given its own list of offsets. If changes to a
4706 particular segment are not needed, the empty list can serve as a
4707 placeholder. In this example the line break makes the single slur
4710 @lilypond[verbatim,quote,ragged-right]
4718 Changing the shapes of the two halves of the slur makes it clearer
4719 that the slur continues over the line break:
4721 @lilypond[verbatim,quote,ragged-right]
4722 % () may be used as a shorthand for ((0 . 0) (0 . 0) (0 . 0) (0 . 0))
4723 % if any of the segments does not need to be changed
4726 (( 0 . 0) (0 . 0) (0 . 0) (0 . 1))
4727 ((0.5 . 1.5) (1 . 0) (0 . 0) (0 . -1.5))
4735 If an S-shaped curve is required the control points must always be
4736 adjusted manually --- LilyPond will never select such shapes
4739 @lilypond[verbatim,quote]
4741 c8( e b-> f d' a e-> g)
4742 \shape #'((0 . -1) (5.5 . -0.5) (-5.5 . -10.5) (0 . -5.5)) PhrasingSlur
4743 c8\( e b-> f d' a e-> g\)
4747 @subsubsubheading Specifying control points explicitly
4749 The coordinates of the Bézier control points are specified in units
4750 of staff-spaces. The X@tie{}coordinate is relative to the reference
4751 point of the note to which the tie or slur is attached, and the
4752 Y@tie{}coordinate is relative to the staff center line. The
4753 coordinates are specified as a list of four pairs of decimal numbers
4754 (reals). One approach is to estimate the coordinates of the two
4755 end points, and then guess the two intermediate points. The optimum
4756 values are then found by trial and error. Be aware that these values
4757 may need to be manually adjusted if any further changes are made to
4758 the music or the layout.
4760 One situation where specifying the control points explicitly is
4761 preferable to specifying displacements is when they need to be
4762 specified relative to a single note. Here is an example of this.
4763 It shows one way of indicating a slur extending into alternative
4764 sections of a volta repeat.
4766 @lilypond[verbatim,quote]
4769 \repeat volta 3 { c4 d( e f }
4774 % create a slur and move it to a new position
4775 % the <> is just an empty chord to carry the slur termination
4776 -\tweak control-points #'((-2 . 3.8) (-1 . 3.9) (0 . 4) (1 . 3.4)) ( <> )
4781 % create a slur and move it to a new position
4782 -\tweak control-points #'((-2 . 3) (-1 . 3.1) (0 . 3.2) (1 . 2.4)) ( <> )
4790 It is not possible to modify shapes of ties or slurs by changing
4791 the @code{control-points} property if there are multiple ties or slurs
4792 at the same musical moment -- the @code{\tweak} command will also not
4793 work in this case. However, the @code{tie-configuration} property of
4794 @code{TieColumn} can be overridden to set start line and direction as
4798 Internals Reference:
4799 @rinternals{TieColumn}.
4802 @node Modifying broken spanners
4803 @subsection Modifying broken spanners
4806 * Using alterBroken::
4809 @node Using alterBroken
4810 @unnumberedsubsubsec Using @code{\alterBroken}
4812 @cindex spanners, modifying
4813 @cindex broken spanners, modifying
4814 @funindex \alterBroken
4816 When a spanner crosses a line break or breaks, each piece
4817 inherits the attributes of the original spanner. Thus, ordinary
4818 tweaking of a broken spanner applies the same modifications to
4819 each of its segments. In the example below, overriding
4820 @code{thickness} affects the slur on either side of the line
4823 @lilypond[verbatim,quote,ragged-right]
4826 \once\override Slur.thickness = 10
4833 Independently modifying the appearance of individual pieces
4834 of a broken spanner is possible with the @code{\alterBroken}
4835 command. This command can produce either an @code{\override}
4836 or a @code{\tweak} of a spanner property.
4838 The syntax for @code{\alterBroken} is
4841 [-]\alterBroken @var{property} @var{values} @var{item}
4844 The argument @var{values} is a list of values, one for each
4845 broken piece. If @var{item} is a grob name like @code{Slur} or
4846 @code{Staff.PianoPedalBracket}, the result is an @code{\override}
4847 of the specified grob type. If @var{item} is a music expression
4848 such as @qq{(} or @qq{[} the result is the same music expression
4849 with an appropriate tweak applied.
4851 The leading hyphen must be used with the @code{\tweak} form. Do
4852 not add it when @code{\alterBroken} is used as an
4855 In its @code{\override} usage, @code{\alterBroken} may be
4856 prefaced by @code{\once} or @code{\temporary} and reverted by
4857 using @code{\revert} with @var{property}.
4859 The following code applies an independent @code{\override} to
4860 each of the slur segments in the previous example:
4862 @lilypond[verbatim,quote,ragged-right]
4865 \alterBroken thickness #'(10 1) Slur
4872 The @code{\alterBroken} command may be used with any spanner
4873 object, including @code{Tie}, @code{PhrasingSlur}, @code{Beam}
4874 and @code{TextSpanner}. For example, an editor preparing a
4875 scholarly edition may wish to indicate the absence of part of a
4876 phrasing slur in a source by dashing only the segment which has
4877 been added. The following example illustrates how this can be
4878 done, in this case using the @code{\tweak} form of the command:
4880 @lilypond[verbatim,quote,ragged-right]
4881 % The empty list is conveniently used below, because it is the
4882 % default setting of dash-definition, resulting in a solid curve.
4884 c''2-\alterBroken dash-definition #'(() ((0 1.0 0.4 0.75))) \(e
4890 It is important to understand that @code{\alterBroken} will set
4891 each piece of a broken spanner to the corresponding value in
4892 @var{values}. When there are fewer values than pieces, any
4893 additional piece will be assigned the empty list. This may lead
4894 to undesired results if the layout property is not set to the
4895 empty list by default. In such cases, each segment should be
4896 assigned an appropriate value.
4899 Line breaks may occur in different places following changes in
4900 layout. Settings chosen for @code{\alterBroken} may be unsuitable
4901 for a spanner that is no longer broken or is split into more
4902 segments than before. Explicit use of @code{\break} can guard
4903 against this situation.
4905 The @code{\alterBroken} command is ineffective for spanner
4906 properties accessed before line-breaking such as
4911 @rextend{Difficult tweaks}.
4914 @node Unpure-pure containers
4915 @subsection Unpure-pure containers
4917 @cindex Scheme, pure containers
4918 @cindex Scheme, unpure containers
4919 @cindex pure containers, Scheme
4920 @cindex unpure containers, Scheme
4921 @cindex horizontal spacing, overriding
4923 Unpure-pure containers are useful for overriding @emph{Y-axis} spacing
4924 calculations - specifically @code{Y-offset} and @code{Y-extent} - with a
4925 Scheme function instead of a literal (i.e., a number or pair).
4927 For certain grobs, the @code{Y-extent} is based on the @code{stencil}
4928 property, overriding the stencil property of one of these will
4929 require an additional @code{Y-extent} override with an unpure-pure
4930 container. When a function overrides a @code{Y-offset} and/or
4931 @code{Y-extent} it is assumed that this will trigger line breaking
4932 calculations too early during compilation. So the function is not
4933 evaluated at all (usually returning a value of @samp{0} or
4934 @samp{'(0 . 0)}) which can result in collisions. A @q{pure} function
4935 will not affect properties, objects or grob suicides and therefore will
4936 always have its Y-axis-related evaluated correctly.
4938 Currently, there are about thirty functions that are already considered
4939 @q{pure} and Unpure-pure containers are a way to set functions not on
4940 this list as @q{pure}. The @q{pure} function is evaluated @emph{before}
4941 any line-breaking and so the horizontal spacing can be adjusted
4942 @q{in time}. The @q{unpure} function is then evaluated @emph{after}
4945 @warning{As it is difficult to always know which functions are on this
4946 list we recommend that any @q{pure} functions you create do not use
4947 @code{Beam} or @code{VerticalAlignment} grobs.}
4949 An unpure-pure container is constructed as follows;
4951 @code{(ly:make-unpure-pure-container f0 f1)}
4953 where @code{f0} is a function taking @var{n} arguments (@var{n >= 1})
4954 and the first argument must always be the grob. This is the function
4955 that gives the actual result. @var{f1} is the function being labeled
4956 as @q{pure} that takes @var{n + 2} arguments. Again, the first argument
4957 must always still be the grob but the second and third are @q{start}
4958 and @q{end} arguments.
4960 @var{start} and @var{end} are, for all intents and purposes, dummy
4961 values that only matter for @code{Spanners} (i.e @code{Hairpin} or
4962 @code{Beam}), that can return different height estimations based on a
4963 starting and ending column.
4965 The rest are the other arguments to the first function (which
4966 may be none if @var{n = 1}).
4968 The results of the second function are used as an approximation of the
4969 value needed which is then used by the first function to get the real
4970 value which is then used for fine-tuning much later during the spacing
4973 @c TODO: The following example supposedly showing a collision no longer
4974 @c 'works' since 2.18.x. Another example of a collision is needed.
4977 @lilypond[verbatim,quote,ragged-right]
4978 #(define (square-line-circle-space grob)
4979 (let* ((pitch (ly:event-property (ly:grob-property grob 'cause) 'pitch))
4980 (notename (ly:pitch-notename pitch)))
4981 (if (= 0 (modulo notename 2))
4982 (make-circle-stencil 0.5 0.0 #t)
4983 (make-filled-box-stencil '(0 . 1.0)
4986 squareLineCircleSpace = {
4987 \override NoteHead.stencil = #square-line-circle-space
4990 smartSquareLineCircleSpace = {
4991 \squareLineCircleSpace
4992 \override NoteHead.Y-extent =
4993 #(ly:make-unpure-pure-container
4994 ly:grob::stencil-height
4995 (lambda (grob start end) (ly:grob::stencil-height grob)))
4998 \new Voice \with { \remove "Stem_engraver" }
5000 \squareLineCircleSpace
5002 \smartSquareLineCircleSpace
5007 In the first measure, without the unpure-pure container, the spacing
5008 engine does not know the width of the note head and lets it collide with
5009 the accidentals. In the second measure, with unpure-pure containers,
5010 the spacing engine knows the width of the note heads and avoids the
5011 collision by lengthening the line accordingly.
5013 Usually for simple calculations nearly-identical functions for
5014 both the @q{unpure} and @q{pure} parts can be used, by only
5015 changing the number of arguments passed to, and the scope of, the
5016 function. This use case is frequent enough that
5017 @code{ly:make-unpure-pure-container} constructs such a second
5018 function by default when called with only one function argument.
5020 @warning{If a function is labeled as @q{pure} and it turns out not to
5021 be, the results can be unexpected.}
5024 @node Using music functions
5025 @section Using music functions
5027 @c TODO -- add @seealso, etc. to these subsections
5029 Where tweaks need to be reused with different music expressions,
5030 it is often convenient to make the tweak part of a @emph{music
5031 function}. In this section, we discuss only @emph{substitution}
5032 functions, where the object is to substitute a variable into a
5033 piece of LilyPond input code. Other more complex functions are
5034 described in @rextend{Music functions}.
5037 * Substitution function syntax::
5038 * Substitution function examples::
5041 @node Substitution function syntax
5042 @subsection Substitution function syntax
5044 Making a function that substitutes a variable into LilyPond
5045 code is easy. The general form of these functions is
5049 #(define-music-function
5050 (@var{arg1} @var{arg2} @dots{})
5051 (@var{type1?} @var{type2?} @dots{})
5053 @var{@dots{}music@dots{}}
5060 @multitable @columnfractions .33 .66
5061 @item @code{@var{argN}}
5062 @tab @var{n}th argument
5064 @item @code{@var{typeN?}}
5065 @tab a scheme @emph{type predicate} for which @code{@var{argN}}
5066 must return @code{#t}.
5068 @item @code{@var{@dots{}music@dots{}}}
5069 @tab normal LilyPond input, using @code{$} (in places where only
5070 LilyPond constructs are allowed) or @code{#} (to use it as a Scheme
5071 value or music function argument or music inside of music lists) to
5076 The list of type predicates is required. Some of the most common
5077 type predicates used in music functions are:
5081 cheap-list? @emph{(use instead of }@q{list?}@emph{ for faster processing)}
5093 For a list of available type predicates, see
5094 @ref{Predefined type predicates}. User-defined type predicates
5099 @ref{Predefined type predicates}.
5102 @rextend{Music functions}.
5105 @file{lily/music-scheme.cc},
5107 @file{scm/lily.scm}.
5110 @node Substitution function examples
5111 @subsection Substitution function examples
5113 This section introduces some substitution function examples.
5114 These are not intended to be exhaustive, but rather to demonstrate
5115 some of the possibilities of simple substitution functions.
5117 In the first example, a function is defined that simplifies
5118 setting the padding of a TextScript:
5120 @lilypond[quote,verbatim,ragged-right]
5122 #(define-music-function
5126 \once \override TextScript.padding = #padding
5130 c''4^"piu mosso" b a b
5132 c4^"piu mosso" b a b
5134 c4^"piu mosso" b a b
5138 In addition to numbers, we can use music expressions such
5139 as notes for arguments to music functions:
5141 @lilypond[quote,verbatim,ragged-right]
5143 #(define-music-function
5147 \tweak NoteHead.stencil #ly:text-interface::print
5148 \tweak NoteHead.text
5149 \markup \musicglyph #"custodes.mensural.u0"
5150 \tweak Stem.stencil ##f
5154 \relative { c'4 d e f \custosNote g }
5158 Both of those functions are simple single expressions where only
5159 the last element of a function call or override is missing. For
5160 those particular function definitions, there is a simpler
5161 alternative syntax, namely just writing out the constant part of
5162 the expression and replacing its final missing element with
5165 @lilypond[quote,verbatim,ragged-right]
5167 \once \override TextScript.padding = \etc
5170 c''4^"piu mosso" b a b
5172 c4^"piu mosso" b a b
5174 c4^"piu mosso" b a b
5178 @lilypond[quote,verbatim,ragged-right]
5180 \tweak NoteHead.stencil #ly:text-interface::print
5181 \tweak NoteHead.text
5182 \markup \musicglyph #"custodes.mensural.u0"
5183 \tweak Stem.stencil ##f
5186 \relative { c'4 d e f \custosNote g }
5190 Substitution functions with multiple arguments can be defined:
5192 @lilypond[quote,verbatim,ragged-right]
5194 #(define-music-function
5198 \once \override Score.MetronomeMark.padding = #padding
5199 \tempo \markup { \bold #tempotext }
5203 \tempo \markup { "Low tempo" }
5205 \tempoPadded #4.0 "High tempo"
5210 @c TODO: add appropriate @@ref's here.