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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
95 I knew it would... And leaving out some of them is perfectly fine
97 I do think that a list like this, with the main contexts and a
99 description of what they do (perhaps also with a note about what
101 behavior is associated with each of them, but this may be
103 should be there, and then we could simply list the remaining ones
105 further explanation and with links to the IR.
108 @c TODO Improve layout, order and consistency of wording -td
110 @c TODO Add introduction which explains contexts in generality -td
112 @c TODO Describe propagation of property values -td
114 Contexts are arranged hierarchically:
117 * Score - the master of all contexts::
118 * Top-level contexts - staff containers::
119 * Intermediate-level contexts - staves::
120 * Bottom-level contexts - voices::
123 @node Score - the master of all contexts
124 @unnumberedsubsubsec Score - the master of all contexts
126 This is the top level notation context. No other context can
127 contain a Score context. By default the Score context handles
128 the administration of time signatures and makes sure that items
129 such as clefs, time signatures, and key-signatures are aligned
132 A Score context is instantiated implicitly when a
133 @code{\score @{@dots{}@}} or @code{\layout @{@dots{}@}} block is
136 @node Top-level contexts - staff containers
137 @unnumberedsubsubsec Top-level contexts - staff containers
139 @strong{@emph{StaffGroup}}
141 Groups staves while adding a bracket on the left side, grouping
142 the staves together. The bar lines of the contained staves are
143 connected vertically. @code{StaffGroup} only consists of a collection
144 of staves, with a bracket in front and spanning bar lines.
146 @strong{@emph{ChoirStaff}}
148 Identical to @code{StaffGroup} except that the bar lines of the
149 contained staves are not connected vertically.
151 @strong{@emph{GrandStaff}}
153 A group of staves, with a brace on the left side, grouping the
154 staves together. The bar lines of the contained staves are
155 connected vertically.
157 @strong{@emph{PianoStaff}}
159 Just like @code{GrandStaff}, but with support for instrument names
160 to the left of each system.
162 @node Intermediate-level contexts - staves
163 @unnumberedsubsubsec Intermediate-level contexts - staves
165 @strong{@emph{Staff}}
167 Handles clefs, bar lines, keys, accidentals. It can contain
168 @code{Voice} contexts.
170 @strong{@emph{RhythmicStaff}}
172 Like @code{Staff} but for printing rhythms. Pitches are ignored;
173 the notes are printed on one line.
175 @strong{@emph{TabStaff}}
177 Context for generating tablature. By default lays the music
178 expression out as a guitar tablature, printed on six lines.
180 @strong{@emph{DrumStaff}}
182 Handles typesetting for percussion. Can contain @code{DrumVoice}
184 @strong{@emph{VaticanaStaff}}
186 Same as @code{Staff}, except that it is designed for typesetting
187 a piece in gregorian style.
189 @strong{@emph{MensuralStaff}}
191 Same as @code{Staff}, except that it is designed for typesetting
192 a piece in mensural style.
194 @node Bottom-level contexts - voices
195 @unnumberedsubsubsec Bottom-level contexts - voices
197 Voice-level contexts initialise certain properties and start
198 appropriate engravers. Being bottom-level contexts, they cannot
199 contain other contexts.
201 @strong{@emph{Voice}}
203 Corresponds to a voice on a staff. This context handles the
204 conversion of dynamic signs, stems, beams, super- and sub-scripts,
205 slurs, ties, and rests. You have to instantiate this explicitly
206 if you require multiple voices on the same staff.
208 @strong{@emph{VaticanaVoice}}
210 Same as @code{Voice}, except that it is designed for typesetting
211 a piece in gregorian style.
213 @strong{@emph{MensuralVoice}}
215 Same as @code{Voice}, with modifications for typesetting a piece in
218 @strong{@emph{Lyrics}}
220 Corresponds to a voice with lyrics. Handles the printing of a
221 single line of lyrics.
223 @strong{@emph{DrumVoice}}
225 The voice context used in a percussion staff.
227 @strong{@emph{FiguredBass}}
229 The context in which @code{BassFigure} objects are created from
230 input entered in @code{\figuremode} mode.
232 @strong{@emph{TabVoice}}
234 The voice context used within a @code{TabStaff} context. Usually
235 left to be created implicitly.
237 @strong{@emph{CueVoice}}
239 A voice context used to render notes of a reduced size, intended
240 primarily for adding cue notes to a staff, see @ref{Formatting
241 cue notes}. Usually left to be created implicitly.
243 @strong{@emph{ChordNames}}
245 Typesets chord names.
250 Then the following, which I don't know what to do with:
252 * GregorianTranscriptionVoice
253 * GregorianTranscriptionStaff
256 Engraves fretboards from chords. Not easy... Not
258 There is now some documentation on FretBoards in the NR, under
259 instrument-specific notation -- cds.
264 Hard coded entry point for LilyPond. Cannot be tuned.
266 Silently discards all musical information given to this
271 @node Creating and referencing contexts
272 @subsection Creating and referencing contexts
277 @cindex referencing contexts
278 @cindex Contexts, creating and referencing
280 LilyPond will create lower-level contexts automatically if a music
281 expression is encountered before a suitable context exists, but this
282 is usually successful only for simple scores or music fragments like
283 the ones in the documentation. For more complex scores it is
284 advisable to specify all contexts explicitly with either the
285 @code{\new} or @code{\context} command. The syntax of
286 these two commands is very similar:
289 [\new | \context] @var{Context} [ = @var{name}] [@var{music-expression}]
293 where either @code{\new} or @code{\context} may be specified.
294 @var{Context} is the type of context which is to be created,
295 @var{name} is an optional name to be given to the particular context
296 being created and @var{music-expression} is a single music expression
297 that is to be interpreted by the engravers and performers in this
300 The @code{\new} prefix without a name is commonly used to create
301 scores with many staves:
303 @lilypond[quote,verbatim,relative=2]
306 % leave the Voice context to be created implicitly
316 and to place several voices into one staff:
318 @lilypond[quote,verbatim,relative=2]
334 @code{\new} should always be used to specify unnamed contexts.
336 The difference between @code{\new} and @code{\context} is in the
341 @code{\new} with or without a name will always create a fresh,
342 distinct, context, even if one with the same name already exists:
344 @lilypond[quote,verbatim,relative=2]
360 @code{\context} with a name specified will create a distinct context
361 only if a context of the same type with the same name in the same
362 context hierarchy does not already exist. Otherwise it will be taken
363 as a reference to that previously created context, and its music
364 expression will be passed to that context for interpretation.
366 One application of named contexts is in separating the score layout
367 from the musical content. Either of these two forms is valid:
369 @lilypond[quote,verbatim]
383 \context Voice = "one" {
388 \context Voice = "two" {
397 @lilypond[quote,verbatim]
402 \context Voice = "one" {
405 \context Voice = "two" {
411 \context Voice = "one" {
416 \context Voice = "two" {
426 Alternatively, variables may be employed to similar effect. See
427 @rlearning{Organizing pieces with variables}.
431 @code{\context} with no name will match the first of any previously
432 created contexts of the same type in the same context heirarchy,
433 even one that has been given a name, and its music expression will be
434 passed to that context for interpretation. This form is rarely
435 useful. However, @code{\context} with no name and no music expression
436 is used to set the context in which a Scheme procedure specified with
437 @code{\applyContext} is executed:
440 \new Staff \relative c' @{
443 \applyContext #(lambda (ctx)
445 (display (ly:context-current-moment ctx)))
452 A context must be named if it is to be referenced later, for example
453 when lyrics are associated with music:
456 \new Voice = "tenor" @var{music}
458 \new Lyrics \lyricsto "tenor" @var{lyrics}
462 For details of associating lyrics with music see
463 @ref{Automatic syllable durations}.
465 The properties of all contexts of a particular type can be modified
466 in a @code{\layout} block (with a different syntax), see
467 @ref{Changing all contexts of the same type}. This construct also
468 provides a means of keeping layout instructions separate from the
469 musical content. If a single context is to be modified, a @code{\with}
470 block must be used, see @ref{Changing just one specific context}.
475 @rlearning{Organizing pieces with variables}.
478 @ref{Changing just one specific context},
479 @ref{Automatic syllable durations}.
482 @node Keeping contexts alive
483 @subsection Keeping contexts alive
485 @cindex contexts, keeping alive
486 @cindex contexts, lifetime
488 Contexts are usually terminated at the first musical moment in
489 which they have nothing to do. So @code{Voice} contexts die as
490 soon as they contain no events; @code{Staff} contexts die as soon
491 as all the @code{Voice} contexts within them contain no events; etc.
492 This can cause difficulties if earlier contexts which have died
493 have to be referenced, for example, when changing staves with
494 @code{\change} commands, associating lyrics with a voice with
495 @code{\lyricsto} commands, or when adding further musical events to
498 There is an exception to this general rule: just one of the
499 @code{Voice} contexts in a @code{Staff} context or in a
500 @code{<<...>>} construct will always persist to the end of the
501 enclosing @code{Staff} context or @code{<<...>>} construct, even
502 though there may be periods when it has nothing to do. The context
503 to persist in this way will be the first one encountered in the
504 first enclosed @code{@{...@}} construct, ignoring any in enclosed
505 @code{<<...>>} constructs.
507 Any context can be kept alive by ensuring it has something to do at
508 every musical moment. @code{Staff} contexts are kept alive by
509 ensuring one of their voices is kept alive. One way of doing this
510 is to add spacer rests to a voice in parallel with the real music.
511 These need to be added to every @code{Voice} context which needs to
512 be kept alive. If several voices are to be used sporadically it is
513 safest to keep them all alive rather than attempting to rely on the
514 exceptions mentioned above.
516 In the following example, both voice A and voice B are kept alive
517 in this way for the duration of the piece:
519 @lilypond[quote,verbatim]
520 musicA = \relative c'' { d4 d d d }
521 musicB = \relative c'' { g4 g g g }
524 \new Voice = "A" { s1*5 } % Keep Voice "A" alive for 5 bars
525 \new Voice = "B" { s1*5 } % Keep Voice "B" alive for 5 bars
530 \context Voice = "A" {
534 \context Voice = "B" {
538 \context Voice = "A" { \musicA }
539 \context Voice = "B" { \musicB }
540 \context Voice = "A" { \musicA }
551 @cindex lyrics, aligning with sporadic melody
553 The following example shows how a sporadic melody line with lyrics
554 might be written using this approach. In a real situation the
555 melody and accompaniment would consist of several different
558 @lilypond[quote,verbatim]
559 melody = \relative c'' { a4 a a a }
560 accompaniment = \relative c' { d4 d d d }
561 words = \lyricmode { These words fol -- low the mel -- o -- dy }
564 \new Staff = "music" {
566 \new Voice = "melody" {
568 s1*4 % Keep Voice "melody" alive for 4 bars
571 \new Voice = "accompaniment" {
576 \context Voice = "melody" { \melody }
577 \context Voice = "accompaniment" { \accompaniment }
579 \context Voice = "accompaniment" { \accompaniment }
581 \context Voice = "melody" { \melody }
582 \context Voice = "accompaniment" { \accompaniment }
587 \new Lyrics \with { alignAboveContext = #"music" }
588 \lyricsto "melody" { \words }
593 An alternative way, which may be better in many circumstances, is
594 to keep the melody line alive by simply including spacer notes to
595 line it up correctly with the accompaniment:
597 @lilypond[quote,verbatim]
598 melody = \relative c'' {
604 accompaniment = \relative c' {
610 words = \lyricmode { These words fol -- low the mel -- o -- dy }
614 \new Staff = "music" {
616 \new Voice = "melody" {
620 \new Voice = "accompaniment" {
626 \new Lyrics \with { alignAboveContext = #"music" }
627 \lyricsto "melody" { \words }
633 @node Modifying context plug-ins
634 @subsection Modifying context plug-ins
636 @c TODO Should this be Modifying engravers or Modifying contexts?
638 Notation contexts (like @code{Score} and @code{Staff}) not only store
639 properties, they also contain plug-ins called @q{engravers} that create
640 notation elements. For example, the @code{Voice} context contains a
641 @code{Note_heads_engraver} and the @code{Staff} context contains a
644 For a full a description of each plug-in, see
646 @rinternals{Engravers and Performers}.
649 Internals Reference @expansion{} Translation @expansion{} Engravers.
651 Every context described in
653 @rinternals{Contexts}
656 Internals Reference @expansion{} Translation @expansion{} Context.
658 lists the engravers used for that context.
661 It can be useful to shuffle around these plug-ins. This is done by
662 starting a new context with @code{\new} or @code{\context}, and
668 \new @var{context} \with @{
681 where the @dots{} should be the name of an engraver. Here is a simple
682 example which removes @code{Time_signature_engraver} and
683 @code{Clef_engraver} from a @code{Staff} context,
685 @lilypond[quote,relative=1,verbatim]
691 \remove "Time_signature_engraver"
692 \remove "Clef_engraver"
699 In the second staff there are no time signature or clef symbols. This
700 is a rather crude method of making objects disappear since it will affect
701 the entire staff. This method also influences the spacing, which may or
702 may not be desirable. More sophisticated methods of blanking objects
703 are shown in @rlearning{Visibility and color of objects}.
705 The next example shows a practical application. Bar lines and time
706 signatures are normally synchronized across the score. This is done
707 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
708 This plug-in keeps an administration of time signature, location
709 within the measure, etc. By moving these engraver from @code{Score} to
710 @code{Staff} context, we can have a score where each staff has its own
713 @cindex polymetric scores
714 @cindex Time signatures, multiple
716 @lilypond[quote,verbatim]
720 \consists "Timing_translator"
721 \consists "Default_bar_line_engraver"
727 \consists "Timing_translator"
728 \consists "Default_bar_line_engraver"
737 \remove "Timing_translator"
738 \remove "Default_bar_line_engraver"
746 The order in which the engravers are specified is the order in
747 which they are called to carry out their processing. Usually the
748 order in which the engravers are specified does not matter, but in
749 a few special cases the order is important, for example where one
750 engraver writes a property and another reads it, or where one
751 engraver creates a grob and another must process it.
753 The following orderings are important:
757 the @code{Bar_engraver} must normally be first,
760 the @code{New_fingering_engraver} must come before the
761 @code{Script_column_engraver},
764 the @code{Timing_translator} must come before the
765 @code{Bar_number_engraver}.
771 @file{ly/engraver-init.ly}.
774 @node Changing context default settings
775 @subsection Changing context default settings
777 @cindex default context properties, changing
778 @cindex context properties, changing defaults
780 Context and grob properties can be changed with @code{\set}
781 and @code{\override} commands, as described in
782 @ref{Modifying properties}. These commands create music events,
783 making the changes take effect at the point in time the music
786 In contrast, this section explains how to change the @emph{default}
787 values of context and grob properties at the time the context is
788 created. There are two ways of doing this. One modifies the default
789 values in all contexts of a particular type, the other modifies the
790 default values in just one particular instance of a context.
793 * Changing all contexts of the same type::
794 * Changing just one specific context::
795 * Order of precedence::
798 @node Changing all contexts of the same type
799 @unnumberedsubsubsec Changing all contexts of the same type
801 @cindex \context in \layout block
805 The context settings which are to be used by default in
806 @code{Score}, @code{Staff}, @code{Voice} and other contexts may be
807 specified in a @code{\context} block within any @code{\layout} block.
808 The @code{\layout} block should be placed within the @code{\score}
809 block to which it is to apply, after the music.
815 [context settings for all Voice contexts]
819 [context settings for all Staff contexts]
824 The following types of settings may be specified:
828 An @code{\override} command, but with the context name omitted
830 @lilypond[quote,verbatim]
833 a4^"Thicker stems" a a a
839 \override Stem.thickness = #4.0
846 Directly setting a context property
848 @lilypond[quote,verbatim]
851 a4^"Smaller font" a a a
864 A predefined command such as @code{\dynamicUp} or a music
865 expression like @code{\accidentalStyle dodecaphonic}
867 @lilypond[quote,verbatim]
870 a4^"Dynamics above" a a a
880 \accidentalStyle dodecaphonic
887 A user-defined variable containing a @code{\with} block; for details
888 of the @code{\with} block see
889 @ref{Changing just one specific context}.
891 @lilypond[quote,verbatim]
892 StaffDefaults = \with {
899 a4^"Smaller font" a a a
914 Property-setting commands can be placed in a @code{\layout} block
915 without being enclosed in a @code{\context} block. Such settings
916 are equivalent to including the same property-setting commands at
917 the start of every context of the type specified. If no context
918 is specified @emph{every} bottom-level context is affected, see
919 @ref{Bottom-level contexts - voices}. The syntax of a
920 property-setting command in a @code{\layout} block is the same as
921 the same command written in the music stream.
923 @lilypond[quote,verbatim]
927 a4^"Smaller font" a a a
932 \accidentalStyle dodecaphonic
934 \override Voice.Stem.thickness = #4.0
940 @node Changing just one specific context
941 @unnumberedsubsubsec Changing just one specific context
946 The context properties of just one specific context instance can be
947 changed in a @code{\with} block. All other context instances of the
948 same type retain the default settings built into LilyPond and modified
949 by any @code{\layout} block within scope. The @code{\with} block
950 must be placed immediately after the @code{\new} @var{context-type}
956 [context settings for this context instance only]
962 The following types of settings may be specified:
966 An @code{\override} command, but with the context name omitted
968 @lilypond[quote,verbatim]
973 \override Stem.thickness = #4.0
977 a4^"Thick stems" a a a
986 Directly setting a context property
988 @lilypond[quote,verbatim]
993 a4^"Default font" a a a
1002 a4^"Smaller font" a a a
1011 A predefined command such as @code{\dynamicUp}
1013 @lilypond[quote,verbatim]
1019 a4^"Dynamics below" a a a
1025 \with { \accidentalStyle dodecaphonic }
1028 \with { \dynamicUp }
1031 a4^"Dynamics above" a a a
1042 @node Order of precedence
1043 @unnumberedsubsubsec Order of precedence
1045 The value of a property which applies at a particular time is
1046 determined as follows:
1050 if an @code{\override} or @code{\set} command in the input stream is
1051 in effect that value is used,
1054 otherwise the default value taken from a @code{\with} statement
1055 on the context initiation statement is used,
1058 otherwise the default value taken from the most recent appropriate
1059 @code{\context} block in the @code{\layout} blocks is used,
1062 otherwise the LilyPond built-in default is used.
1067 @rlearning{Modifying context properties}.
1070 @ref{Contexts explained},
1071 @ref{Bottom-level contexts - voices},
1072 @ref{The set command},
1073 @ref{The override command},
1074 @ref{The \layout block}.
1077 @node Defining new contexts
1078 @subsection Defining new contexts
1080 @cindex contexts, defining new
1081 @cindex engravers, including in contexts
1096 Specific contexts, like @code{Staff} and @code{Voice}, are made of
1097 simple building blocks. It is possible to create new types of
1098 contexts with different combinations of engraver plug-ins.
1100 The next example shows how to build a different type of
1101 @code{Voice} context from scratch. It will be similar to
1102 @code{Voice}, but only prints centered slash note heads. It can be used
1103 to indicate improvisation in jazz pieces,
1105 @lilypond[quote,ragged-right]
1106 \layout { \context {
1108 \type "Engraver_group"
1109 \consists "Note_heads_engraver"
1110 \consists "Rhythmic_column_engraver"
1111 \consists "Text_engraver"
1112 \consists "Pitch_squash_engraver"
1113 squashedPosition = #0
1114 \override NoteHead.style = #'slash
1115 \override Stem.transparent = ##t
1116 \override Flag.transparent = ##t
1120 \accepts "ImproVoice"
1124 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
1125 c4 c^"undress" c_"while playing :)" c }
1131 These settings are defined within a @code{\context} block inside a
1132 @code{\layout} block,
1142 In the following discussion, the example input shown should go in place
1143 of the @dots{} in the previous fragment.
1145 First it is necessary to define a name for the new context:
1151 Since it is similar to the @code{Voice}, we want commands that work
1152 on (existing) @code{Voice}s to remain working. This is achieved by
1153 giving the new context an alias @code{Voice},
1159 The context will print notes and instructive texts, so we need to add
1160 the engravers which provide this functionality,
1163 \consists "Note_heads_engraver"
1164 \consists "Text_engraver"
1167 but we only need this on the center line,
1170 \consists "Pitch_squash_engraver"
1171 squashedPosition = #0
1174 The @rinternals{Pitch_squash_engraver} modifies note heads (created
1175 by @rinternals{Note_heads_engraver}) and sets their vertical
1176 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
1179 The notes look like a slash, and have no stem,
1182 \override NoteHead.style = #'slash
1183 \override Stem.transparent = ##t
1184 \override Flag.transparent = ##t
1187 All these plug-ins have to cooperate, and this is achieved with a
1188 special plug-in, which must be marked with the keyword @code{\type}.
1189 This should always be @code{Engraver_group}.
1192 \type "Engraver_group"
1195 Put together, we get
1200 \type "Engraver_group"
1201 \consists "Note_heads_engraver"
1202 \consists "Text_engraver"
1203 \consists "Pitch_squash_engraver"
1204 squashedPosition = #0
1205 \override NoteHead.style = #'slash
1206 \override Stem.transparent = ##t
1207 \override Flag.transparent = ##t
1213 Contexts form hierarchies. We want to hang the @code{ImproVoice}
1214 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
1215 modify the @code{Staff} definition with the @code{\accepts}
1226 The opposite of @code{\accepts} is @code{\denies},
1227 which is sometimes needed when reusing existing context definitions.
1229 Putting both into a @code{\layout} block, like
1239 \accepts "ImproVoice"
1244 Then the output at the start of this subsection can be entered as
1252 c c_"while playing :)"
1259 @node Context layout order
1260 @subsection Context layout order
1262 @cindex contexts, layout order
1266 Contexts are normally positioned in a system from top to bottom
1267 in the order in which they are encountered in the input file. When
1268 contexts are nested, the outer context will include inner nested
1269 contexts as specified in the input file, provided the inner contexts
1270 are included in the outer context's @qq{accepts} list. Nested
1271 contexts which are not included in the outer context's @qq{accepts}
1272 list will be repositioned below the outer context rather than nested
1275 The @qq{accepts} list of a context can be changed with the
1276 @code{\accepts} and @code{\denies} commands. @code{\accepts} adds a
1277 context to the @qq{accepts} list and @code{\denies} removes a context
1278 from the list. For example, it would not normally be desirable for
1279 chord names to be nested within a @code{Staff} context, so the
1280 @code{ChordNames} context is not included by default in the @qq{accepts}
1281 list of the @code{Staff} context, but if this were to be required it can
1284 @lilypond[verbatim,quote]
1288 \chords { d1:m7 b1:min7.5- }
1293 @lilypond[verbatim,quote]
1297 \chords { d1:m7 b1:min7.5- }
1302 \accepts "ChordNames"
1308 @code{\denies} is mainly used when a new context is being based on
1309 another, but the required nesting differs. For example, the
1310 @code{VaticanaStaff} context is based on the @code{Staff} context, but
1311 with the @code{VaticanaVoice} context substituted for the @code{Voice}
1312 context in the @qq{accepts} list.
1314 Note that a context will be silently created implicitly if a command
1315 is encountered when there is no suitable context available to
1316 contain it. This can give rise to unexpected new staves or scores.
1318 @cindex alignAboveContext
1319 @cindex alignBelowContext
1320 @funindex alignAboveContext
1321 @funindex alignBelowContext
1323 Sometimes a context is required to exist for just a brief period, a
1324 good example being the staff context for an ossia. This is usually
1325 achieved by introducing the context definition at the appropriate
1326 place in parallel with corresponding section of the main music.
1327 By default, the temporary context will be placed below all the
1328 existing contexts. To reposition it above the context called
1329 @qq{main}, it should be defined like this:
1332 @code{\new Staff \with @{ alignAboveContext = #"main" @} }
1335 A similar situation arises when positioning a temporary lyrics
1336 context within a multi-staved layout such as a @code{ChoirStaff},
1337 for example, when adding a second verse to a repeated section.
1338 By default the temporary lyrics context will be placed beneath the
1339 lower staves. By defining the temporary lyrics context with
1340 @code{alignBelowContext} it can be positioned correctly beneath
1341 the (named) lyrics context containing the first verse.
1343 Examples showing this repositioning of temporary contexts can be
1344 found elsewhere --- see @rlearning{Nesting music expressions},
1345 @ref{Modifying single staves} and @ref{Techniques specific to lyrics}.
1349 @rlearning{Nesting music expressions}.
1352 @ref{Modifying single staves},
1353 @ref{Techniques specific to lyrics}.
1356 @rprogram{An extra staff appears}.
1359 @file{ly/engraver-init.ly}.
1362 @node Explaining the Internals Reference
1363 @section Explaining the Internals Reference
1366 * Navigating the program reference::
1367 * Layout interfaces::
1368 * Determining the grob property::
1369 * Naming conventions::
1372 @node Navigating the program reference
1373 @subsection Navigating the program reference
1375 @c TODO remove this (it's in the LM)
1376 @c Replace with more factual directions
1378 Suppose we want to move the fingering indication in the fragment
1381 @lilypond[quote,relative=2,verbatim]
1387 If you visit the documentation on fingering instructions (in
1388 @ref{Fingering instructions}), you will notice:
1393 Internals Reference: @rinternals{Fingering}.
1398 @c outdated info; probably will delete.
1400 This fragment points to two parts of the program reference: a page
1401 on @code{FingeringEvent} and one on @code{Fingering}.
1403 The page on @code{FingeringEvent} describes the properties of the music
1404 expression for the input @w{@code{-2}}. The page contains many links
1405 forward. For example, it says
1408 Accepted by: @rinternals{Fingering_engraver},
1412 That link brings us to the documentation for the Engraver, the
1416 This engraver creates the following layout objects: @rinternals{Fingering}.
1419 In other words, once the @code{FingeringEvent}s are interpreted, the
1420 @code{Fingering_engraver} plug-in will process them.
1424 @c I can't figure out what this is supposed to mean. -gp
1426 The @code{Fingering_engraver} is also listed to create
1427 @rinternals{Fingering} objects,
1429 @c old info? it doesn't make any sense to me with our current docs.
1431 second bit of information listed under @b{See also} in the Notation
1436 The programmer's reference is available as an HTML document. It is
1437 highly recommended that you read it in HTML form, either online or
1438 by downloading the HTML documentation. This section will be much more
1439 difficult to understand if you are using the
1443 Follow the link to @rinternals{Fingering}. At the top of the
1447 Fingering objects are created by: @rinternals{Fingering_engraver} and
1448 @rinternals{New_fingering_engraver}.
1451 By following related links inside the program reference, we can follow the
1452 flow of information within the program:
1456 @item @rinternals{Fingering}:
1457 @rinternals{Fingering} objects are created by:
1458 @rinternals{Fingering_engraver}
1460 @item @rinternals{Fingering_engraver}:
1461 Music types accepted: @rinternals{fingering-event}
1463 @item @rinternals{fingering-event}:
1464 Music event type @code{fingering-event} is in Music expressions named
1465 @rinternals{FingeringEvent}
1468 This path goes against the flow of information in the program: it
1469 starts from the output, and ends at the input event. You could
1470 also start at an input event, and read with the flow of
1471 information, eventually ending up at the output object(s).
1473 The program reference can also be browsed like a normal document. It
1474 contains chapters on
1476 @rinternals{Music definitions},
1479 @code{Music definitions}
1481 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1482 chapter lists all the definitions used and all properties that may be
1486 @node Layout interfaces
1487 @subsection Layout interfaces
1489 @cindex interface, layout
1490 @cindex layout interface
1493 The HTML page that we found in the previous section describes the
1494 layout object called @rinternals{Fingering}. Such an object is a
1495 symbol within the score. It has properties that store numbers (like
1496 thicknesses and directions), but also pointers to related objects. A
1497 layout object is also called a @emph{Grob}, which is short for Graphical
1498 Object. For more details about Grobs, see @rinternals{grob-interface}.
1500 The page for @code{Fingering} lists the definitions for the
1501 @code{Fingering} object. For example, the page says
1504 @code{padding} (dimension, in staff space):
1510 which means that the number will be kept at a distance of at least 0.5
1514 Each layout object may have several functions as a notational or
1515 typographical element. For example, the Fingering object
1516 has the following aspects
1520 Its size is independent of the horizontal spacing, unlike slurs or beams.
1523 It is a piece of text. Granted, it is usually a very short text.
1526 That piece of text is typeset with a font, unlike slurs or beams.
1529 Horizontally, the center of the symbol should be aligned to the
1530 center of the note head.
1533 Vertically, the symbol is placed next to the note and the staff.
1536 The vertical position is also coordinated with other superscript
1537 and subscript symbols.
1540 Each of these aspects is captured in so-called @emph{interface}s,
1541 which are listed on the @rinternals{Fingering} page at the bottom
1544 This object supports the following interfaces:
1545 @rinternals{item-interface},
1546 @rinternals{self-alignment-interface},
1547 @rinternals{side-position-interface}, @rinternals{text-interface},
1548 @rinternals{text-script-interface}, @rinternals{font-interface},
1549 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1552 Clicking any of the links will take you to the page of the respective
1553 object interface. Each interface has a number of properties. Some of
1554 them are not user-serviceable (@q{Internal properties}), but others
1557 We have been talking of @emph{the} @code{Fingering} object, but actually it
1558 does not amount to much. The initialization file (see
1559 @rlearning{Other sources of information})
1560 @file{scm/define-grobs.scm} shows the soul of the @q{object},
1565 (avoid-slur . around)
1566 (slur-padding . 0.2)
1567 (staff-padding . 0.5)
1568 (self-alignment-X . 0)
1569 (self-alignment-Y . 0)
1570 (script-priority . 100)
1571 (stencil . ,ly:text-interface::print)
1572 (direction . ,ly:script-interface::calc-direction)
1573 (font-encoding . fetaText)
1574 (font-size . -5) ; don't overlap when next to heads.
1575 (meta . ((class . Item)
1576 (interfaces . (finger-interface
1578 text-script-interface
1580 side-position-interface
1581 self-alignment-interface
1582 item-interface))))))
1586 As you can see, the @code{Fingering} object is nothing more than a
1587 bunch of variable settings, and the webpage in the Internals Reference
1588 is directly generated from this definition.
1591 @node Determining the grob property
1592 @subsection Determining the grob property
1594 @c TODO remove this (it's in the LM)
1595 @c Replace with more factual directions
1597 Recall that we wanted to change the position of the @b{2} in
1599 @lilypond[quote,relative=2,verbatim]
1605 Since the @b{2} is vertically positioned next to its note, we have to
1606 meddle with the interface associated with this positioning. This is
1607 done using @code{side-position-interface}. The page for this interface
1611 @code{side-position-interface}
1613 Position a victim object (this one) next to other objects (the
1614 support). The property @code{direction} signifies where to put the
1615 victim object relative to the support (left or right, up or down?)
1620 Below this description, the variable @code{padding} is described as
1625 (dimension, in staff space)
1627 Add this much extra space between objects that are next to each other.
1631 By increasing the value of @code{padding}, we can move the
1632 fingering away from the note head. The following command inserts
1633 3 staff spaces of white
1634 between the note and the fingering:
1636 \once \override Voice.Fingering.padding = #3
1639 Inserting this command before the Fingering object is created,
1640 i.e., before @code{c2}, yields the following result:
1642 @lilypond[quote,relative=2,verbatim]
1643 \once \override Voice.Fingering.padding = #3
1650 In this case, the context for this tweak is @code{Voice}. This
1651 fact can also be deduced from the program reference, for the page for
1652 the @rinternals{Fingering_engraver} plug-in says
1655 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1659 @node Naming conventions
1660 @subsection Naming conventions
1662 Another thing that is needed, is an overview of the various naming
1666 @item scheme functions: lowercase-with-hyphens (incl. one-word
1668 @item scheme functions: ly:plus-scheme-style
1669 @item music events, music classes and music properties:
1671 @item Grob interfaces: scheme-style
1672 @item backend properties: scheme-style (but X and Y!)
1673 @item contexts (and MusicExpressions and grobs): Capitalized or
1675 @item context properties: lowercaseFollowedByCamelCase
1677 Capitalized_followed_by_lowercase_and_with_underscores
1680 Questions to be answered:
1682 @item Which of these are conventions and which are rules?
1683 @item Which are rules of the underlying language, and which are
1687 @node Modifying properties
1688 @section Modifying properties
1690 @c TODO change the menu and subsection node names to use
1691 @c backslash once the new macro to handle the refs
1692 @c is available. Need to find and change all refs at
1693 @c the same time. -td
1696 * Overview of modifying properties::
1698 * The override command::
1699 * The tweak command::
1700 * set versus override::
1701 * Modifying alists::
1705 @node Overview of modifying properties
1706 @subsection Overview of modifying properties
1708 Each context is responsible for creating certain types of graphical
1709 objects. The settings used for printing these objects are also stored by
1710 context. By changing these settings, the appearance of objects can be
1713 There are two different kinds of properties stored in contexts:
1714 context properties and grob properties. Context properties are
1715 properties that apply to the context as a whole and control
1716 how the context itself is displayed. In contrast, grob properties
1717 apply to specific grob types that will be displayed in the context.
1719 The @code{\set} and @code{\unset} commands are used to change values
1720 for context properties. The @code{\override} and @code{\revert}
1721 commands are used to change values for grob properties.
1724 The syntax for this is
1727 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1730 Here @var{name} is the name of a graphical object, like
1731 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1732 variable of the formatting system (@q{grob property} or @q{layout
1733 property}). The latter is a symbol, so it must be quoted. The
1734 subsection @ref{Modifying properties}, explains what to fill in
1735 for @var{name}, @var{property}, and @var{value}. Here we only
1736 discuss the functionality of this command.
1741 \override Staff.Stem.thickness = #4.0
1745 makes stems thicker (the default is 1.3, with staff line thickness as a
1746 unit). Since the command specifies @code{Staff} as context, it only
1747 applies to the current staff. Other staves will keep their normal
1748 appearance. Here we see the command in action:
1750 @lilypond[quote,verbatim,relative=2]
1752 \override Staff.Stem.thickness = #4.0
1758 The @code{\override} command changes the definition of the @code{Stem}
1759 within the current @code{Staff}. After the command is interpreted
1760 all stems are thickened.
1762 Analogous to @code{\set}, the @var{context} argument may be left out,
1763 causing the default context @code{Voice} to be used. Adding
1764 @code{\once} applies the change during one timestep only.
1766 @lilypond[quote,verbatim,relative=2]
1768 \once \override Stem.thickness = #4.0
1773 The @code{\override} must be done before the object is
1774 started. Therefore, when altering @emph{Spanner} objects such as slurs
1775 or beams, the @code{\override} command must be executed at the moment
1776 when the object is created. In this example,
1778 @lilypond[quote,verbatim,relative=2]
1779 \override Slur.thickness = #3.0
1781 \override Beam.beam-thickness = #0.6
1786 the slur is fatter but the beam is not. This is because the command for
1787 @code{Beam} comes after the Beam is started, so it has no effect.
1789 Analogous to @code{\unset}, the @code{\revert} command for a context
1790 undoes an @code{\override} command; like with @code{\unset}, it only
1791 affects settings that were made in the same context. In other words, the
1792 @code{\revert} in the next example does not do anything.
1795 \override Voice.Stem.thickness = #4.0
1796 \revert Staff.Stem.thickness
1799 Some tweakable options are called @q{subproperties} and reside inside
1800 properties. To tweak those, use commands of the form
1802 @c leave this as a long long
1804 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1811 \override Stem.details.beamed-lengths = #'(4 4 3)
1817 Internals Reference:
1818 @rinternals{Backend},
1819 @rinternals{All layout objects},
1820 @rinternals{OverrideProperty},
1821 @rinternals{RevertProperty},
1822 @rinternals{PropertySet}.
1825 The back-end is not very strict in type-checking object properties.
1826 Cyclic references in Scheme values for properties can cause hangs
1827 or crashes, or both.
1830 @node The set command
1831 @subsection The @code{@bs{}set} command
1835 @cindex changing properties
1837 Each context has a set of @emph{properties}, variables contained
1838 in that context. Context properties are changed with the @code{\set}
1839 command, which has the following syntax:
1842 \set @var{context}.@var{property} = #@var{value}
1845 @var{value} is a Scheme object, which is why it must be preceded by
1846 the @code{#}@tie{}character.
1848 Contexts properties are usually named in
1849 @code{studlyCaps}. They mostly control the translation from
1850 music to notation, e.g. @code{localKeySignature} (for determining
1851 whether to print accidentals), or @code{measurePosition} (for
1852 determining when to print a bar line). Context properties can
1853 change value over time while interpreting a piece of music;
1854 @code{measurePosition} is an obvious example of
1855 this. Context properties are modified with @code{\set}.
1857 For example, multimeasure rests will be combined into a single bar
1858 if the context property @code{skipBars} is set to @code{#t}:
1860 @lilypond[quote,verbatim,relative=2]
1862 \set Score.skipBars = ##t
1866 If the @var{context} argument is left out, then the property will be
1867 set in the current bottom context (typically @code{ChordNames},
1868 @code{Voice}, @code{TabVoice}, or @code{Lyrics}).
1870 @lilypond[quote,verbatim,relative=2]
1871 \set Score.autoBeaming = ##f
1875 \set autoBeaming = ##t
1883 The change is applied @q{on-the-fly}, during the music, so that the
1884 setting only affects the second group of eighth notes.
1886 Note that the bottom-most context does not always contain the property
1887 that you wish to change -- for example, attempting to set the
1888 @code{skipBars} property of the default bottom context, in this case
1889 @code{Voice}, will have no effect, because skipBars is a property of
1890 the @code{Score} context.
1892 @lilypond[quote,verbatim,relative=2]
1898 Contexts are hierarchical, so if an enclosing context was specified, for
1899 example @code{Staff}, then the change would also apply to all
1900 @code{Voice}s in the current staff.
1904 The @code{\unset} command:
1907 \unset @var{context}.@var{property}
1911 is used to remove the definition of @var{property} from
1912 @var{context}. This command removes
1913 the definition only if it is set in @var{context}.
1914 Properties that have been set in enclosing contexts will
1915 not be altered by an unset in an enclosed context:
1917 @lilypond[quote,verbatim,relative=2]
1918 \set Score.autoBeaming = ##t
1923 \unset Score.autoBeaming
1931 Like @code{\set}, the @var{context} argument does not have to be
1932 specified for a bottom context, so the two statements
1935 \set Voice.autoBeaming = ##t
1936 \set autoBeaming = ##t
1940 are equivalent if the current bottom context is @code{Voice}.
1944 Preceding a @code{\set} command by @code{\once} makes the
1945 setting apply to only a single time-step:
1947 @lilypond[quote,verbatim,relative=2]
1949 \once \set fontSize = #4.7
1954 A full description of all available context properties is in the
1955 internals reference, see
1957 @rinternals{Tunable context properties}.
1960 Translation @expansion{} Tunable context properties.
1964 Internals Reference:
1965 @rinternals{Tunable context properties}.
1967 @cindex grob properties
1968 @cindex properties, grob
1972 @node The override command
1973 @subsection The @code{\override} command
1975 There is a special type of context property: the grob
1976 description. Grob descriptions are named in @code{StudlyCaps}
1977 (starting with capital letters). They contain the
1978 @q{default settings} for a particular kind of grob as an
1979 association list. See @file{scm/define-grobs.scm}
1980 to see the settings for each grob description. Grob descriptions
1981 are modified with @code{\override}.
1983 The syntax for the @code{\override} command is
1986 \override [@var{context}.]@var{GrobName}.@var{property} = #@var{value}
1989 For example, we can increase the thickness of a note stem by
1990 overriding the @code{thickness} property of the @code{Stem}
1993 @lilypond[quote,verbatim,relative=2]
1995 \override Voice.Stem.thickness = #3.0
1999 If no context is specified in an @code{\override}, the bottom
2002 @lilypond[quote,verbatim,relative=2]
2003 { \override Staff.Stem.thickness = #3.0
2007 \override Stem.thickness = #0.5
2016 Some tweakable options are called @q{subproperties} and reside inside
2017 properties. To tweak those, use commands in the form
2020 \override Stem.details.beamed-lengths = #'(4 4 3)
2023 or to modify the ends of spanners, use a form like these
2026 \override TextSpanner.bound-details.left.text = #"left text"
2027 \override TextSpanner.bound-details.right.text = #"right text"
2031 @cindex reverting overrides
2032 @cindex overrides, reverting
2034 The effects of @code{\override} can be undone by @code{\revert}.
2036 The syntax for the @code{\revert} command is
2039 \revert [@var{context}.]@var{GrobName}.@var{property}
2044 @lilypond[quote,verbatim,relative=2]
2046 \override Voice.Stem.thickness = #3.0
2048 \revert Voice.Stem.thickness
2052 The effects of @code{\override} and @code{\revert} apply to all
2053 grobs in the affected context from the current time forward:
2055 @lilypond[quote,verbatim,relative=2]
2060 \override Staff.Stem.thickness = #3.0
2064 \revert Staff.Stem.thickness
2072 @cindex overriding for only one moment
2074 @code{\once} can be used with @code{\override}
2075 to affect only the current time step:
2077 @lilypond[quote,verbatim,relative=2]
2081 \override Stem.thickness = #3.0
2085 \once \override Stem.thickness = #3.0
2094 Commands which change output generally look like
2097 \override Voice.Stem.thickness = #3.0
2101 To construct this tweak we must determine these bits of information:
2104 @item the context: here @code{Voice}.
2105 @item the layout object: here @code{Stem}.
2106 @item the layout property: here @code{thickness}.
2107 @item a sensible value: here @code{3.0}.
2110 @cindex internal documentation
2111 @cindex finding graphical objects
2112 @cindex graphical object descriptions
2115 @cindex internal documentation
2117 For many properties, regardless of the data type of the property, setting the
2118 property to false (@code{#f}) will result in turning it off, causing
2119 LilyPond to ignore that property entirely. This is particularly useful for
2120 turning off grob properties which may otherwise be causing problems.
2122 We demonstrate how to glean this information from the notation manual
2123 and the program reference.
2127 Internals Reference:
2128 @rinternals{Backend}
2131 @node The tweak command
2132 @subsection The @code{\tweak} command
2137 Changing grob properties
2138 with @code{\override} causes the changes to apply to all of the
2139 given grobs in the context at the moment the change applies.
2140 Sometimes, however, it is desirable to have changes apply to just
2141 one grob, rather than to all grobs in the affected context. This is
2142 accomplished with the @code{\tweak} command, which has the following
2146 \tweak [@var{layout-object}.]@var{grob-property} @var{value}
2149 Specifying @var{layout-object} is optional.
2150 The @code{\tweak} command applies to the music object that immediately
2151 follows @var{value} in the music stream.
2154 In some cases, it is possible to take a short-cut for tuning
2155 graphical objects. For objects that are created directly from
2156 an item in the input file, you can use the @code{\tweak} command.
2159 @lilypond[relative=2,verbatim,quote]
2164 \tweak duration-log #1
2173 The main use of the @code{\tweak} command is to modify just
2174 one of a number of notation elements which start at the same musical
2175 moment, like the notes of a chord, or tuplet brackets which start
2178 The @code{\tweak} command sets a property in the following object
2179 directly, without requiring the grob name or context to be
2180 specified. For this to work, it is necessary for the @code{\tweak}
2181 command to remain immediately adjacent to the object to which it is
2182 to apply after the input file has been converted to a music stream.
2183 This is often not the case, as many additional elements are inserted
2184 into the music stream implicitly. For example, when a note which is
2185 not part of a chord is processed, LilyPond implicitly inserts a
2186 @code{ChordEvent} event before the note, so separating the tweak
2187 from the note. However, if chord symbols are placed round the
2188 tweak and the note, the @code{\tweak} command comes after the
2189 @code{ChordEvent} in the music stream, so remaining adjacent to the
2190 note, and able to modify it.
2194 @lilypond[relative=2,verbatim,quote]
2195 <\tweak color #red c>4
2201 @lilypond[relative=2,verbatim,quote]
2202 \tweak color #red c4
2207 For an introduction to the syntax and uses of the tweak command
2208 see @rlearning{Tweaking methods}.
2210 When several similar items are placed at the same musical moment,
2211 the @code{\override} command cannot be used to modify just one of
2212 them -- this is where the @code{\tweak} command must be used.
2213 Items which may appear more than once at the same musical moment
2214 include the following:
2216 @c TODO expand to include any further uses of \tweak
2218 @item note heads of notes inside a chord
2219 @item articulation signs on a single note
2220 @item ties between notes in a chord
2221 @item tuplet brackets starting at the same time
2224 @c TODO add examples of these
2226 @cindex chord, modifying one note in
2228 In this example, the color of one note head and the type of another
2229 note head are modified within a single chord:
2231 @lilypond[relative=2,verbatim,quote]
2236 \tweak duration-log #1
2241 @code{\tweak} can be used to modify slurs:
2243 @lilypond[verbatim,quote,relative=1]
2244 c-\tweak thickness #5 ( d e f)
2248 For the @code{\tweak} command to work, it must
2249 remain immediately adjacent to the object to which it is
2250 to apply after the input file has been converted to a music stream.
2251 Tweaking a whole chord does not do anything since its music event
2252 only acts as a container, and all layout objects are created from events
2253 inside of the @code{EventChord}:
2255 @lilypond[relative=2,verbatim,quote]
2256 \tweak color #red c4
2257 \tweak color #red <c e>4
2258 <\tweak color #red c e>4
2261 The simple @code{\tweak} command cannot be used to modify any object
2262 that is not directly created from the input. In particular
2263 it will not affect stems, automatic
2264 beams or accidentals, since these are generated later by
2265 @code{NoteHead} layout objects rather than by music elements in the
2268 Such indirectly created layout objects can be tweaked using the form
2269 of the @code{\tweak} command in which the grob name is specified
2272 @lilypond[relative=2,verbatim,quote]
2273 \tweak Stem.color #red
2274 \tweak Beam.color #green c8 e
2275 <c e \tweak Accidental.font-size #-3 ges>4
2278 @code{\tweak} cannot be used to modify clefs or time
2279 signatures, since these become separated from any preceding
2280 @code{\tweak} command in the input stream by the automatic
2281 insertion of extra elements required to specify the context.
2283 Several @code{\tweak} commands may be placed before a
2284 notational element -- all affect it:
2286 @lilypond[verbatim,quote,relative=1]
2288 -\tweak style #'dashed-line
2289 -\tweak dash-fraction #0.2
2290 -\tweak thickness #3
2296 The music stream which is generated from a section of an input file,
2297 including any automatically inserted elements, may be examined,
2298 see @rextend{Displaying music expressions}. This may be helpful in
2299 determining what may be modified by a @code{\tweak} command, or
2300 in determining how to adjust the input to make a @code{\tweak}
2305 @rlearning{Tweaking methods}.
2308 @rextend{Displaying music expressions}.
2312 @cindex tweaking control points
2313 @cindex control points, tweaking
2315 The @code{\tweak} command cannot be used to modify the control
2316 points of just one of several ties in a chord, other than the first
2317 one encountered in the input file.
2319 @node set versus override
2320 @subsection @code{\set} vs. @code{\override}
2322 @c TODO -- This section is probably unnecessary now.
2325 We have seen two methods of changing properties: @code{\set} and
2326 @code{\override}. There are actually two different kinds of
2329 @code{fontSize} is a special property: it is equivalent to
2330 entering @code{\override ... #'font-size} for all pertinent
2331 objects. Since this is a common change, the special
2332 property (modified with @code{\set}) was created.
2337 @node Modifying alists
2338 @subsection Modifying alists
2340 Some user-configurable properties are internally represented as
2341 @emph{alists} (association lists), which store pairs of
2342 @emph{keys} and @emph{values}. The structure of an alist is:
2345 '((@var{key1} . @var{value1})
2346 (@var{key2} . @var{value2})
2347 (@var{key3} . @var{value3})
2351 If an alist is a grob property or @code{\paper} variable, its keys
2352 can be modified individually without affecting other keys.
2354 For example, to reduce the space between adjacent staves in a
2355 staff-group, use the @code{staff-staff-spacing} property of the
2356 @code{StaffGrouper} grob. The property is an alist with four
2357 keys: @code{basic-distance}, @code{minimum-distance},
2358 @code{padding}, and @code{stretchability}. The standard settings
2359 for this property are listed in the @qq{Backend} section of the
2360 Internals Reference (see @rinternals{StaffGrouper}):
2363 '((basic-distance . 9)
2364 (minimum-distance . 7)
2366 (stretchability . 5))
2369 One way to bring the staves closer together is by reducing the
2370 value of the @code{basic-distance} key (@code{9}) to match the
2371 value of @code{minimum-distance} (@code{7}). To modify a single
2372 key individually, use a @emph{nested declaration}:
2374 @lilypond[quote,verbatim]
2375 % default space between staves
2377 \new Staff { \clef treble c''1 }
2378 \new Staff { \clef bass c1 }
2381 % reduced space between staves
2382 \new PianoStaff \with {
2383 % this is the nested declaration
2384 \override StaffGrouper.staff-staff-spacing.basic-distance = #7
2386 \new Staff { \clef treble c''1 }
2387 \new Staff { \clef bass c1 }
2391 Using a nested declaration will update the specified key (such as
2392 @code{basic-distance} in the above example) without altering any
2393 other keys already set for the same property.
2395 Now suppose we want the staves to be as close as possible without
2396 overlapping. The simplest way to do this is to set all four alist
2397 keys to zero. However, it is not necessary to enter four nested
2398 declarations, one for each key. Instead, the property can be
2399 completely re-defined with one declaration, as an alist:
2401 @lilypond[quote,verbatim]
2402 \new PianoStaff \with {
2403 \override StaffGrouper.staff-staff-spacing =
2404 #'((basic-distance . 0)
2405 (minimum-distance . 0)
2407 (stretchability . 0))
2409 \new Staff { \clef treble c''1 }
2410 \new Staff { \clef bass c1 }
2414 Note that any keys not explicitly listed in the alist definition
2415 will be reset to their @emph{default-when-unset} values. In the
2416 case of @code{staff-staff-spacing}, any unset key-values would be
2417 reset to zero (except @code{stretchability}, which takes the value
2418 of @code{basic-distance} when unset). Thus the following two
2419 declarations are equivalent:
2422 \override StaffGrouper.staff-staff-spacing =
2423 #'((basic-distance . 7))
2425 \override StaffGrouper.staff-staff-spacing =
2426 #'((basic-distance . 7)
2427 (minimum-distance . 0)
2429 (stretchability . 7))
2432 One (possibly unintended) consequence of this is the removal of
2433 any standard settings that are set in an initialization file and
2434 loaded each time an input file is compiled. In the above example,
2435 the standard settings for @code{padding} and
2436 @code{minimum-distance} (defined in @file{scm/define-grobs.scm})
2437 are reset to their default-when-unset values (zero for both keys).
2438 Defining a property or variable as an alist (of any size) will
2439 always reset all unset key-values to their default-when-unset
2440 values. Unless this is the intended result, it is safer to update
2441 key-values individually with a nested declaration.
2443 @warning{Nested declarations will not work for context property
2444 alists (such as @code{beamExceptions}, @code{keySignature},
2445 @code{timeSignatureSettings}, etc.). These properties can only be
2446 modified by completely re-defining them as alists.}
2449 @node Useful concepts and properties
2450 @section Useful concepts and properties
2455 * Direction and placement::
2456 * Distances and measurements::
2457 * Staff symbol properties::
2459 * Visibility of objects::
2461 * Rotating objects::
2465 @subsection Input modes
2467 The way in which the notation contained within an input file is
2468 interpreted is determined by the current input mode.
2472 This is activated with the @code{\chordmode} command, and causes
2473 input to be interpreted with the syntax of chord notation, see
2474 @ref{Chord notation}. Chords are rendered as notes on a staff.
2476 Chord mode is also activated with the @code{\chords} command.
2477 This also creates a new @code{ChordNames} context and
2478 causes the following input to be interpreted with the syntax of
2479 chord notation and rendered as chord names in the @code{ChordNames}
2480 context, see @ref{Printing chord names}.
2484 This is activated with the @code{\drummode} command, and causes
2485 input to be interpreted with the syntax of drum notation, see
2486 @ref{Basic percussion notation}.
2488 Drum mode is also activated with the @code{\drums} command.
2489 This also creates a new @code{DrumStaff} context and causes the
2490 following input to be interpreted with the syntax of drum notation
2491 and rendered as drum symbols on a drum staff, see @ref{Basic
2492 percussion notation}.
2494 @strong{Figure mode}
2496 This is activated with the @code{\figuremode} command, and causes
2497 input to be interpreted with the syntax of figured bass, see
2498 @ref{Entering figured bass}.
2500 Figure mode is also activated with the @code{\figures} command.
2501 This also creates a new @code{FiguredBass} context and causes the
2502 following input to be interpreted with the figured bass syntax
2503 and rendered as figured bass symbols in the @code{FiguredBass}
2504 context, see @ref{Introduction to figured bass}.
2506 @strong{Fret and tab modes}
2508 There are no special input modes for entering fret and tab symbols.
2510 To create tab diagrams, enter notes or chords in note mode and
2511 render them in a @code{TabStaff} context, see
2512 @ref{Default tablatures}.
2514 To create fret diagrams above a staff, you have two choices.
2515 You can either use the @code{FretBoards} context (see
2516 @ref{Automatic fret diagrams} or you can enter them as a markup
2517 above the notes using the @code{\fret-diagram} command (see
2518 @ref{Fret diagram markups}).
2520 @strong{Lyrics mode}
2522 This is activated with the @code{\lyricmode} command, and causes
2523 input to be interpreted as lyric syllables with optional durations
2524 and associated lyric modifiers, see @ref{Vocal music}.
2526 Lyric mode is also activated with the @code{\addlyrics} command.
2527 This also creates a new @code{Lyrics} context and an implicit
2528 @code{\lyricsto} command which associates the following lyrics
2529 with the preceding music.
2531 @strong{Markup mode}
2533 This is activated with the @code{\markup} command, and causes
2534 input to be interpreted with the syntax of markup, see
2535 @ref{Text markup commands}.
2537 @c silly work-around for texinfo broken-ness
2538 @c (@strong{Note...} causes a spurious cross-reference in Info)
2541 This is the default mode or it may be activated with the
2542 @code{\notemode} command. Input is interpreted as pitches,
2543 durations, markup, etc and typeset as musical notation on a staff.
2545 It is not normally necessary to specify note mode explicitly, but
2546 it may be useful to do so in certain situations, for example if you
2547 are in lyric mode, chord mode or any other mode and want to insert
2548 something that only can be done with note mode syntax.
2550 For example, to indicate dynamic markings for the verses of a
2551 choral pieces it is necessary to enter note mode to interpret
2554 @lilypond[verbatim,relative=2,quote]
2557 \notemode{\set stanza = \markup{ \dynamic f 1. } }
2561 \notemode{\set stanza = \markup{ \dynamic p 2. } }
2568 @node Direction and placement
2569 @subsection Direction and placement
2571 In typesetting music the direction and placement of many items is
2572 a matter of choice. For example, the stems of notes can
2573 be directed up or down; lyrics, dynamics, and other expressive
2574 marks may be placed above or below the staff; text may be aligned
2575 left, right or center; etc. Most of these choices may be left to
2576 be determined automatically by LilyPond, but in some cases it may
2577 be desirable to force a particular direction or placement.
2580 * Articulation direction indicators::
2581 * The direction property::
2584 @node Articulation direction indicators
2585 @unnumberedsubsubsec Articulation direction indicators
2587 By default some directions are always up or always down (e.g.
2588 dynamics or fermata), while other things can alternate between
2589 up or down based on the stem direction (like slurs or accents).
2591 @c TODO Add table showing these
2593 The default action may be overridden by prefixing the articulation
2594 by a @emph{direction indicator}. Three direction indicators are
2595 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
2596 and @code{-} (meaning @qq{use default direction}). The direction
2597 indicator can usually be omitted, in which case @code{-} is assumed,
2598 but a direction indicator is @strong{always} required before
2601 @item @code{\tweak} commands
2602 @item @code{\markup} commands
2603 @item @code{\tag} commands
2604 @item string markups, e.g. -"string"
2605 @item fingering instructions, e.g. @w{@code{-1}}
2606 @item articulation shortcuts, e.g. @w{@code{-.}}, @w{@code{->}}, @w{@code{--}}
2609 Direction indicators affect only the next note:
2611 @lilypond[verbatim,quote,relative=2]
2618 @node The direction property
2619 @unnumberedsubsubsec The direction property
2621 The position or direction of many layout objects is controlled by the
2622 @code{direction} property.
2624 The value of the @code{direction} property may be set to @code{1},
2625 meaning @qq{up} or @qq{above}, or to @w{@code{-1}}, meaning @qq{down} or
2626 @qq{below}. The symbols @code{UP} and @code{DOWN} may be used instead
2627 of @code{1} and @w{@code{-1}} respectively. The default direction may
2628 be specified by setting @code{direction} to @code{0} or @code{CENTER}.
2629 Alternatively, in many cases predefined commands exist to specify the
2630 direction. These are of the form
2633 @code{\xxxUp}, @code{\xxxDown} or @code{\xxxNeutral}
2637 where @code{\xxxNeutral} means @qq{use the default} direction.
2638 See @rlearning{Within-staff objects}.
2640 In a few cases, arpeggio for example, the value of the @code{direction}
2641 property can specify whether the object is to be placed to the right or
2642 left of the parent. In this case @w{@code{-1}} or @code{LEFT} means
2643 @qq{to the left} and @code{1} or @code{RIGHT} means @qq{to the right}.
2644 @code{0} or @code{CENTER} means @qq{use the default} direction.
2647 These all have side-axis set to #X
2648 AmbitusAccidental - direction has no effect
2650 StanzaNumber - not tried
2651 TrillPitchAccidental - not tried
2652 TrillPitchGroup - not tried
2655 These indications affect all notes until they are canceled.
2657 @lilypond[verbatim,quote,relative=2]
2666 In polyphonic music, it is generally better to specify an explicit
2667 @code{voice} than change an object's direction. For more information.
2668 See @ref{Multiple voices}.
2672 @rlearning{Within-staff objects}.
2675 @ref{Multiple voices}.
2678 @node Distances and measurements
2679 @subsection Distances and measurements
2681 @cindex distances, absolute
2682 @cindex distances, scaled
2689 Distances in LilyPond are of two types: absolute and scaled.
2691 Absolute distances are used for specifying margins, indents, and
2692 other page layout details, and are by default specified in
2693 millimeters. Distances may be specified in other units by
2694 following the quantity by @code{\mm}, @code{\cm},
2695 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27 of
2696 an inch). Page layout distances can also be specified in scalable
2697 units (see the following paragraph) by appending
2698 @code{\staff-space} to the quantity. Page layout is described in
2699 detail in @ref{Page layout}.
2701 Scaled distances are always specified in units of the staff-space
2702 or, rarely, the half staff-space. The staff-space is the distance
2703 between two adjacent staff lines. The default value can be changed
2704 globally by setting the global staff size, or it can be overridden
2705 locally by changing the @code{staff-space} property of
2706 @code{StaffSymbol}. Scaled distances automatically scale with any
2707 change to the either the global staff size or the
2708 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2709 automatically only with changes to the global staff size.
2710 The global staff size thus enables the overall size of a rendered
2711 score to be easily varied. For the methods of setting the global
2712 staff size see @ref{Setting the staff size}.
2716 If just a section of a score needs to be rendered to a different
2717 scale, for example an ossia section or a footnote, the global staff
2718 size cannot simply be changed as this would affect the entire score.
2719 In such cases the change in size is made by overriding both the
2720 @code{staff-space} property of @code{StaffSymbol} and the size of
2721 the fonts. A Scheme function, @code{magstep}, is available to
2722 convert from a font size change to the equivalent change in
2723 @code{staff-space}. For an explanation and an example of its use,
2724 see @rlearning{Length and thickness of objects}.
2728 @rlearning{Length and thickness of objects}.
2732 @ref{Setting the staff size}.
2735 @node Staff symbol properties
2736 @subsection Staff symbol properties
2738 @cindex adjusting staff symbol
2739 @cindex drawing staff symbol
2740 @cindex staff symbol, setting of
2742 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2743 @c Need to think of uses for these properties. Eg 'line-positions
2744 @c is used in a snippet to thicken centre line.
2745 @c If retained, add @ref to here in 1.6.2 -td
2747 The vertical position of staff lines and the number of staff lines
2748 can be defined at the same time. As the following example shows,
2749 note positions are not influenced by the staff line positions.
2751 @warning{The @code{'line-positions} property overrides the
2752 @code{'line-count} property. The number of staff lines is
2753 implicitly defined by the number of elements in the list of values
2754 for @code{'line-positions}.}
2756 @lilypond[verbatim,quote,relative=1]
2758 \override StaffSymbol.line-positions = #'(7 3 0 -4 -6 -7)
2763 The width of a staff can be modified. The units are staff
2764 spaces. The spacing of objects inside the staff is not affected by
2767 @lilypond[verbatim,quote,relative=1]
2769 \override StaffSymbol.width = #23
2776 @subsection Spanners
2778 Many objects of musical notation extend over several notes or even
2779 several bars. Examples are slurs, beams, tuplet brackets, volta
2780 repeat brackets, crescendi, trills, and glissandi. Such objects
2781 are collectively called @qq{spanners}, and have special properties to control
2782 their appearance and behaviour. Some of these properties are common
2783 to all spanners; others are restricted to a sub-set of the spanners.
2785 All spanners support the @code{spanner-interface}. A few, essentially
2786 those that draw a straight line between the two objects, support in
2787 addition the @code{line-spanner-interface}.
2790 * Using the spanner-interface::
2791 * Using the line-spanner-interface::
2794 @node Using the spanner-interface
2795 @unnumberedsubsubsec Using the @code{spanner-interface}
2797 This interface provides two properties that apply to several spanners.
2799 @subsubsubheading The @code{minimum-length} property
2801 The minimum length of the spanner is specified by the
2802 @code{minimum-length} property. Increasing this usually has the
2803 necessary effect of increasing the spacing of the notes between the
2804 two end points. However, this override has no effect on
2805 many spanners, as their length is determined by other considerations.
2806 A few examples where it is effective are shown below.
2816 Works as long as callback is made:
2820 Works not at all for:
2829 @lilypond[verbatim,quote,relative=2]
2832 % increase the length of the tie
2833 -\tweak minimum-length #5
2837 @lilypond[verbatim,quote,relative=2]
2839 \compressFullBarRests
2841 % increase the length of the rest bar
2842 \once \override MultiMeasureRest.minimum-length = #20
2847 @lilypond[verbatim,quote,relative=2]
2849 % increase the length of the hairpin
2850 \override Hairpin.minimum-length = #20
2854 This override can also be used to increase the length of slurs and
2857 @lilypond[verbatim,quote,relative=2]
2860 -\tweak minimum-length #5
2865 -\tweak minimum-length #5
2869 For some layout objects, the @code{minimum-length} property becomes
2870 effective only if the @code{set-spacing-rods} procedure is called
2871 explicitly. To do this, the @code{springs-and-rods} property should
2872 be set to @code{ly:spanner::set-spacing-rods}. For example,
2873 the minimum length of a glissando has no effect unless the
2874 @code{springs-and-rods} property is set:
2876 @lilypond[verbatim,quote,relative=1]
2880 % not effective alone
2881 \once \override Glissando.minimum-length = #20
2884 % effective only when both overrides are present
2885 \once \override Glissando.minimum-length = #20
2886 \once \override Glissando.springs-and-rods = #ly:spanner::set-spacing-rods
2890 The same is true of the @code{Beam} object:
2892 @lilypond[verbatim,quote,relative=1]
2893 % not effective alone
2894 \once \override Beam.minimum-length = #20
2897 % effective only when both overrides are present
2898 \once \override Beam.minimum-length = #20
2899 \once \override Beam.springs-and-rods = #ly:spanner::set-spacing-rods
2903 @subsubsubheading The @code{to-barline} property
2905 The second useful property of the @code{spanner-interface} is
2906 @code{to-barline}. By default this is true, causing hairpins and
2907 other spanners which are terminated on the first note of a measure to
2908 end instead on the immediately preceding bar line. If set to false,
2909 the spanner will extend beyond the bar line and end on the note
2912 @lilypond[verbatim,quote,relative=2]
2913 a \< a a a a \! a a a \break
2914 \override Hairpin.to-barline = ##f
2915 a \< a a a a \! a a a
2918 This property is not effective for all spanners. For example,
2919 setting it to @code{#t} has no effect on slurs or phrasing slurs
2920 or on other spanners for which terminating on the bar line would
2923 @node Using the line-spanner-interface
2924 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2926 Objects which support the @code{line-spanner-interface} include
2929 @item @code{DynamicTextSpanner}
2930 @item @code{Glissando}
2931 @item @code{TextSpanner}
2932 @item @code{TrillSpanner}
2933 @item @code{VoiceFollower}
2936 The routine responsible for drawing the stencils for these spanners is
2937 @code{ly:line-interface::print}. This routine determines the
2938 exact location of the two end points and draws a line
2939 between them, in the style requested. The locations of the two
2940 end points of the spanner are computed on-the-fly, but it is
2941 possible to override their Y-coordinates. The
2942 properties which need to be specified are nested
2943 two levels down within the property hierarchy, but the syntax of
2944 the @code{\override} command is quite simple:
2946 @lilypond[relative=2,quote,verbatim]
2948 \once \override Glissando.bound-details.left.Y = #3
2949 \once \override Glissando.bound-details.right.Y = #-2
2953 The units for the @code{Y} property are @code{staff-space}s,
2954 with the center line of the staff being the zero point.
2955 For the glissando, this is the value for @code{Y} at the
2956 X-coordinate corresponding to the center point of each note head,
2957 if the line is imagined to be extended to there.
2959 If @code{Y} is not set, the value is computed from the vertical
2960 position of the corresponding attachment point of the spanner.
2962 In case of a line break, the values for the end points are
2963 specified by the @code{left-broken} and @code{right-broken}
2964 sub-lists of @code{bound-details}. For example:
2966 @lilypond[relative=2,ragged-right,verbatim,quote]
2967 \override Glissando.breakable = ##t
2968 \override Glissando.bound-details.right-broken.Y = #-3
2969 c1 \glissando \break
2974 A number of further properties of the @code{left} and
2975 @code{right} sub-lists of the @code{bound-details} property
2976 may be modified in the same way as @code{Y}:
2980 This sets the Y-coordinate of the end point, in @code{staff-space}s
2981 offset from the staff center line. By default, it is the center of
2982 the bound object, so a glissando points to the vertical center of
2985 For horizontal spanners, such as text spanners and trill spanners,
2986 it is hardcoded to 0.
2989 This determines where the line starts and ends in the X-direction,
2990 relative to the bound object. So, a value of @w{@code{-1}} (or
2991 @code{LEFT}) makes the line start/end at the left side of the note
2992 head it is attached to.
2995 This is the absolute X-coordinate of the end point. It is usually
2996 computed on the fly, and overriding it has little useful effect.
2999 Line spanners may have symbols at the beginning or end, which is
3000 contained in this sub-property. This is for internal use; it is
3001 recommended that @code{text} be used instead.
3004 This is a markup that is evaluated to yield the stencil. It is used
3005 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
3007 @lilypond[quote,ragged-right,relative=2,verbatim]
3008 \override TextSpanner.bound-details.left.text
3009 = \markup { \small \bold Slower }
3010 c2\startTextSpan b c a\stopTextSpan
3013 @item stencil-align-dir-y
3014 @item stencil-offset
3015 Without setting one of these, the stencil is simply put at the
3016 end-point, centered on the line, as defined by the @code{X} and
3017 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
3018 or @code{stencil-offset} will move the symbol at the edge vertically
3019 relative to the end point of the line:
3021 @lilypond[relative=1,quote,verbatim]
3022 \override TextSpanner.bound-details.left.stencil-align-dir-y = #-2
3023 \override TextSpanner.bound-details.right.stencil-align-dir-y = #UP
3025 \override TextSpanner.bound-details.left.text = #"ggg"
3026 \override TextSpanner.bound-details.right.text = #"hhh"
3027 c4^\startTextSpan c c c \stopTextSpan
3030 Note that negative values move the text @emph{up}, contrary to the
3031 effect that might be expected, as a value of @w{@code{-1}} or
3032 @code{DOWN} means align the @emph{bottom} edge of the text with
3033 the spanner line. A value of @code{1} or @code{UP} aligns
3034 the top edge of the text with the spanner line.
3037 Setting this sub-property to @code{#t} produces an arrowhead at the
3041 This sub-property controls the space between the specified
3042 end point of the line and the actual end. Without padding, a
3043 glissando would start and end in the center of each note head.
3047 The music function @code{\endSpanners} terminates the spanner
3048 which starts on the immediately following note prematurely. It
3049 is terminated after exactly one note, or at the following bar line
3050 if @code{to-barline} is true and a bar line occurs before the next
3053 @lilypond[verbatim,quote,ragged-right,relative=2]
3055 c2 \startTextSpan c2 c2
3060 When using @code{\endSpanners} it is not necessary to close
3061 \startTextSpan with \stopTextSpan, nor is it necessary to close
3062 hairpins with @code{\!}.
3065 Internals Reference:
3066 @rinternals{TextSpanner},
3067 @rinternals{Glissando},
3068 @rinternals{VoiceFollower},
3069 @rinternals{TrillSpanner},
3070 @rinternals{line-spanner-interface}.
3073 @node Visibility of objects
3074 @subsection Visibility of objects
3076 @cindex objects, visibility of
3077 @cindex grobs, visibility of
3078 @cindex visibility of objects
3080 There are four main ways in which the visibility of layout objects
3081 can be controlled: their stencil can be removed, they can be made
3082 transparent, they can be colored white, or their
3083 @code{break-visibility} property can be overridden. The first
3084 three apply to all layout objects; the last to just a few -- the
3085 @emph{breakable} objects. The Learning Manual introduces these
3086 four techniques, see @rlearning{Visibility and color of objects}.
3088 There are also a few other techniques which are specific to
3089 certain layout objects. These are covered under Special
3093 * Removing the stencil::
3094 * Making objects transparent::
3095 * Painting objects white::
3096 * Using break-visibility::
3097 * Special considerations::
3101 @node Removing the stencil
3102 @unnumberedsubsubsec Removing the stencil
3104 @cindex stencil, removing
3106 Every layout object has a stencil property. By default this is set
3107 to the specific function which draws that object. If this property
3108 is overridden to @code{#f} no function will be called and the object
3109 will not be drawn. The default action can be recovered with
3112 @lilypond[quote,verbatim,relative=1]
3114 \override Score.BarLine.stencil = ##f
3116 \revert Score.BarLine.stencil
3120 @node Making objects transparent
3121 @unnumberedsubsubsec Making objects transparent
3123 @cindex transparent, making objects
3125 Every layout object has a transparent property which by default is
3126 set to @code{#f}. If set to @code{#t} the object still occupies
3127 space but is made invisible.
3129 @lilypond[quote,verbatim,relative=2]
3131 \once \override NoteHead.transparent = ##t
3135 @node Painting objects white
3136 @unnumberedsubsubsec Painting objects white
3138 @cindex objects, coloring
3139 @cindex coloring objects
3141 @cindex printing order
3142 @cindex overwriting objects
3143 @cindex objects, overwriting
3144 @cindex grobs, overwriting
3146 Every layout object has a color property which by default is set
3147 to @code{black}. If this is overridden to @code{white} the object
3148 will be indistinguishable from the white background. However,
3149 if the object crosses other objects the color of the crossing
3150 points will be determined by the order in which they are drawn,
3151 and this may leave a ghostly image of the white object, as shown
3154 @lilypond[quote,verbatim,relative=2]
3155 \override Staff.Clef.color = #white
3159 This may be avoided by changing the order of printing the objects.
3160 All layout objects have a @code{layer} property which should be set
3161 to an integer. Objects with the lowest value of @code{layer} are
3162 drawn first, then objects with progressively higher values are drawn,
3163 so objects with higher values overwrite objects with lower values.
3164 By default most objects are assigned a @code{layer} value of
3165 @code{1}, although a few objects, including @code{StaffSymbol} and
3166 @code{BarLine}, are assigned a value of @code{0}. The order of
3167 printing objects with the same value of @code{layer} is indeterminate.
3169 In the example above the white clef, with a default @code{layer}
3170 value of @code{1}, is drawn after the staff lines (default
3171 @code{layer} value @code{0}), so overwriting them. To change this,
3172 the @code{Clef} object must be given in a lower value of
3173 @code{layer}, say @w{@code{-1}}, so that it is drawn earlier:
3175 @lilypond[quote,verbatim,relative=2]
3176 \override Staff.Clef.color = #white
3177 \override Staff.Clef.layer = #-1
3181 @node Using break-visibility
3182 @unnumberedsubsubsec Using break-visibility
3184 @c TODO Add making other objects breakable
3186 @cindex break-visibility
3188 Most layout objects are printed only once, but some like
3189 bar lines, clefs, time signatures and key signatures, may need
3190 to be printed twice when a line break occurs -- once at the end
3191 of the line and again at the start of the next line. Such
3192 objects are called @emph{breakable}, and have a property, the
3193 @code{break-visibility} property to control their visibility
3194 at the three positions in which they may appear -- at the
3195 start of a line, within a line if they are changed, and at the
3196 end of a line if a change takes place there.
3198 For example, the time signature
3199 by default will be printed at the start of the first line, but
3200 nowhere else unless it changes, when it will be printed at the
3201 point at which the change occurs. If this change occurs at the
3202 end of a line the new time signature will be printed at the start
3203 of the next line and a cautionary time signature will be printed
3204 at the end of the previous line as well.
3206 This behaviour is controlled by the @code{break-visibility}
3207 property, which is explained in
3208 @c Leave this ref on a newline - formats incorrectly otherwise -td
3209 @rlearning{Visibility and color of objects}. This property takes
3210 a vector of three booleans which, in order, determine whether the
3211 object is printed at the end of, within the body of, or at the
3212 beginning of a line. Or to be more precise, before a line break,
3213 where there is no line break, or after a line break.
3215 Alternatively, these eight combinations may be specified
3216 by pre-defined functions, defined in @file{scm/output-lib.scm},
3217 where the last three columns indicate whether the layout objects
3218 will be visible in the positions shown at the head of the columns:
3220 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {Before} {At no} {After}
3221 @headitem Function @tab Vector @tab Before @tab At no @tab After
3222 @headitem form @tab form @tab break @tab break @tab break
3224 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
3225 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
3226 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
3227 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
3228 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
3229 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
3230 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
3231 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
3234 The default settings of @code{break-visibility} depend on the
3235 layout object. The following table shows all the layout objects
3236 of interest which are affected by @code{break-visibility} and the
3237 default setting of this property:
3239 @multitable @columnfractions .3 .3 .4
3241 @headitem Layout object @tab Usual context @tab Default setting
3243 @c omit Ambitus as it appears not to be affected by break-visibility -td
3244 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
3245 @item @code{BarLine} @tab @code{Score} @tab calculated
3246 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
3247 @c omit the following item until it can be explained -td
3248 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
3249 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
3250 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
3251 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
3252 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
3253 @item @code{KeyCancellation} @tab @code{Staff} @tab @code{begin-of-line-invisible}
3254 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
3255 @c omit LeftEdge until it can be explained -td
3256 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
3257 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
3258 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
3259 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
3263 The example below shows the use of the vector form to control the
3264 visibility of bar lines:
3266 @lilypond[quote,verbatim,relative=1,ragged-right]
3269 % Remove bar line at the end of the current line
3270 \once \override Score.BarLine.break-visibility = ##(#f #t #t)
3276 Although all three components of the vector used to override
3277 @code{break-visibility} must be present, not all of them are
3278 effective with every layout object, and some combinations may
3279 even give errors. The following limitations apply:
3282 @item Bar lines cannot be printed at start of line.
3283 @item A bar number cannot be printed at the start of the first
3284 line unless it is set to be different from 1.
3285 @item Clef -- see below
3286 @item Double percent repeats are either all printed or all
3287 suppressed. Use begin-of line-invisible to print and
3288 all-invisible to suppress.
3289 @item Key signature -- see below
3290 @item OctavateEight -- see below
3293 @node Special considerations
3294 @unnumberedsubsubsec Special considerations
3296 @subsubsubheading Visibility following explicit changes
3298 @cindex key signature, visibility following explicit change
3299 @cindex explicitKeySignatureVisibility
3300 @cindex clef, visibility following explicit change
3301 @cindex explicitClefVisibility
3303 The @code{break-visibility} property controls the visibility of
3304 key signatures and changes of clef only at the start of lines,
3305 i.e. after a break. It has no effect on the visibility of the
3306 key signature or clef following an explicit key change or an
3307 explicit clef change within or at the end of a line. In the
3308 following example the key signature following the explicit change
3309 to B-flat major is still visible, even though @code{all-invisible}
3312 @lilypond[quote,verbatim,relative=1,ragged-right]
3315 % Try to remove all key signatures
3316 \override Staff.KeySignature.break-visibility = #all-invisible
3324 The visibility of such explicit key signature and clef changes is
3325 controlled by the @code{explicitKeySignatureVisibility} and
3326 @code{explicitClefVisibility} properties. These are the equivalent
3327 of the @code{break-visibility} property and both take a vector of
3328 three booleans or the predefined functions listed above, exactly like
3329 @code{break-visibility}. Both are properties of the Staff context,
3330 not the layout objects themselves, and so they are set using the
3331 @code{\set} command. Both are set by default to @code{all-visible}.
3332 These properties control only the visibility of key signatures and
3333 clefs resulting from explicit changes and do not affect key
3334 signatures and clefs at the beginning of lines;
3335 @code{break-visibility} must still be overridden in the appropriate
3336 object to remove these.
3338 @lilypond[quote,verbatim,relative=1,ragged-right]
3341 \set Staff.explicitKeySignatureVisibility = #all-invisible
3342 \override Staff.KeySignature.break-visibility = #all-invisible
3349 @subsubsubheading Visibility of cancelling accidentals
3351 To remove the cancelling accidentals printed at an explicit key
3352 change, set the Staff context property @code{printKeyCancellation}
3355 @lilypond[quote,verbatim,relative=1,ragged-right]
3358 \set Staff.explicitKeySignatureVisibility = #all-invisible
3359 \set Staff.printKeyCancellation = ##f
3360 \override Staff.KeySignature.break-visibility = #all-invisible
3367 With these overrides only the accidentals before the notes remain
3368 to indicate the change of key.
3370 Note that when changing the key to C@tie{}major or A@tie{}minor
3371 the cancelling accidentals would be the @emph{only} indication of
3372 the key change. In this case setting @code{printKeyCancellation} to
3373 @code{#f} has no effect:
3375 @lilypond[quote,verbatim,relative=1,ragged-right]
3378 \set Staff.explicitKeySignatureVisibility = #all-invisible
3379 \set Staff.printKeyCancellation = ##f
3386 To suppress the cancelling accidentals even when the key is
3387 changed to C@tie{}major or A@tie{}minor, override
3388 the visibility of the @code{KeyCancellation} grob instead:
3390 @lilypond[quote,verbatim,relative=1,ragged-right]
3393 \set Staff.explicitKeySignatureVisibility = #all-invisible
3394 \override Staff.KeyCancellation.break-visibility = #all-invisible
3401 @c TODO Add visibility of cautionary accidentals before notes
3403 @subsubsubheading Automatic bars
3405 @cindex automaticBars
3406 @cindex bar lines, suppressing
3408 As a special case, the printing of bar lines can also be turned off
3409 by setting the @code{automaticBars} property in the Score context.
3410 If set to @code{#f}, bar lines will not be printed automatically;
3411 they must be explicitly created with a @code{\bar} command. Unlike
3412 the @code{\cadenzaOn} predefined command, measures are still counted.
3413 Bar generation will resume according to that count if this property
3414 is later set to @code{#t}. When set to @code{#f}, line breaks can
3415 occur only at explicit @code{\bar} commands.
3419 @subsubsubheading Octavated clefs
3421 @cindex octavated clefs, visibility of
3422 @cindex visibility of octavated clefs
3423 @cindex clefs, visibility of octavation
3425 The small octavation symbol on octavated clefs is produced by the
3426 @code{OctavateEight} layout object. Its visibility is automatically
3427 inherited from the @code{Clef} object, so it is not necessary to apply
3428 any required @code{break-visibility} overrides to the @code{OctavateEight}
3429 layout objects to suppress octavation symbols for invisible clefs.
3431 For explicit clef changes, the @code{explicitClefVisibility}
3432 property controls both the clef symbol and any octavation symbol
3437 @rlearning{Visibility and color of objects}.
3441 @subsection Line styles
3443 Some performance indications, e.g., @i{rallentando} and
3444 @i{accelerando} and @i{trills} are written as text and are
3445 extended over many measures with lines, sometimes dotted or wavy.
3447 These all use the same routines as the glissando for drawing the
3448 texts and the lines, and tuning their behavior is therefore also
3449 done in the same way. It is done with a spanner, and the routine
3450 responsible for drawing the spanners is
3451 @code{ly:line-interface::print}. This routine determines the
3452 exact location of the two @i{span points} and draws a line
3453 between them, in the style requested.
3455 Here is an example showing the different line styles available,
3456 and how to tune them.
3458 @lilypond[relative=2,ragged-right,verbatim,quote]
3460 \once \override Glissando.style = #'dashed-line
3462 \override Glissando.style = #'dotted-line
3464 \override Glissando.style = #'zigzag
3466 \override Glissando.style = #'trill
3470 The locations of the end-points of the spanner are computed
3471 on-the-fly for every graphic object, but it is possible to
3475 @lilypond[relative=2,ragged-right,verbatim,quote]
3477 \once \override Glissando.bound-details.right.Y = #-2
3481 The value for @code{Y} is set to @w{@code{-2}} for the right end
3482 point. The left side may be similarly adjusted by specifying
3483 @code{left} instead of @code{right}.
3485 If @code{Y} is not set, the value is computed from the vertical
3486 position of the left and right attachment points of the spanner.
3488 Other adjustments of spanners are possible, for details, see
3491 @node Rotating objects
3492 @subsection Rotating objects
3494 Both layout objects and elements of markup text can be rotated by
3495 any angle about any point, but the method of doing so differs.
3498 * Rotating layout objects::
3502 @node Rotating layout objects
3503 @unnumberedsubsubsec Rotating layout objects
3505 @cindex rotating objects
3506 @cindex objects, rotating
3508 All layout objects which support the @code{grob-interface} can be
3509 rotated by setting their @code{rotation} property. This takes a
3510 list of three items: the angle of rotation counter-clockwise,
3511 and the x and y coordinates of the point relative to the object's
3512 reference point about which the rotation is to be performed. The
3513 angle of rotation is specified in degrees and the coordinates in
3516 The angle of rotation and the coordinates of the rotation point must
3517 be determined by trial and error.
3519 @cindex hairpins, angled
3520 @cindex angled hairpins
3522 There are only a few situations where the rotation of layout
3523 objects is useful; the following example shows one situation where
3526 @lilypond[quote,verbatim,relative=1]
3528 \override Hairpin.rotation = #'(20 -1 0)
3532 @node Rotating markup
3533 @unnumberedsubsubsec Rotating markup
3535 All markup text can be rotated to lie at any angle by prefixing it
3536 with the @code{\rotate} command. The command takes two arguments:
3537 the angle of rotation in degrees counter-clockwise and the text to
3538 be rotated. The extents of the text are not rotated: they take
3539 their values from the extremes of the x and y coordinates of the
3540 rotated text. In the following example the
3541 @code{outside-staff-priority} property for text is set to @code{#f}
3542 to disable the automatic collision avoidance, which would push some
3543 of the text too high.
3545 @lilypond[quote,verbatim,relative=1]
3546 \override TextScript.outside-staff-priority = ##f
3547 g4^\markup { \rotate #30 "a G" }
3548 b^\markup { \rotate #30 "a B" }
3549 des^\markup { \rotate #30 "a D-Flat" }
3550 fis^\markup { \rotate #30 "an F-Sharp" }
3553 @node Advanced tweaks
3554 @section Advanced tweaks
3556 This section discusses various approaches to fine tuning the
3557 appearance of the printed score.
3560 * Aligning objects::
3561 * Vertical grouping of grobs::
3562 * Modifying stencils::
3563 * Modifying shapes::
3564 * Unpure-pure containers::
3569 @rlearning{Tweaking output},
3570 @rlearning{Other sources of information}.
3573 @ref{Explaining the Internals Reference},
3574 @ref{Modifying properties}.
3577 @rextend{Interfaces for programmers}.
3580 @file{scm/define-grobs.scm}.
3583 @rlsr{Tweaks and overrides}.
3585 Internals Reference:
3586 @rinternals{All layout objects}.
3589 @node Aligning objects
3590 @subsection Aligning objects
3592 Graphical objects which support the @code{self-alignment-interface}
3593 and/or the @code{side-position-interface} can be aligned to a previously
3594 placed object in a variety of ways. For a list of these objects, see
3595 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
3597 All graphical objects have a reference point, a horizontal extent and a
3598 vertical extent. The horizontal extent is a pair of numbers
3599 giving the displacements from the reference point of the left and
3600 right edges, displacements to the left being negative. The vertical
3601 extent is a pair of numbers giving the displacement from the reference
3602 point to the bottom and top edges, displacements down being negative.
3604 An object's position on a staff is given by the values of the
3605 @code{X-offset} and @code{Y-offset} properties. The value of
3606 @code{X-offset} gives the displacement from the X coordinate of
3607 the reference point of the parent object, and the value of
3608 @code{Y-offset} gives the displacement from the center line of the
3609 staff. The values of @code{X-offset} and @code{Y-offset} may
3610 be set directly or may be set to be calculated by procedures in order
3611 to achieve alignment with the parent object.
3613 @warning{Many objects have special positioning considerations which
3614 cause any setting of @code{X-offset} or @code{Y-offset} to be
3615 ignored or modified, even though the object supports the
3616 @code{self-alignment-interface}. Overriding the @code{X-offset}
3617 or @code{Y-offset} properties to a fixed value causes the respective
3618 @code{self-alignment} property to be disregarded.}
3620 For example, an accidental can be repositioned vertically by setting
3621 @code{Y-offset} but any changes to @code{X-offset} have no effect.
3623 Rehearsal marks may be aligned with breakable objects such as bar
3624 lines, clef symbols, time signature symbols and key signatures. There
3625 are special properties to be found in the @code{break-aligned-interface}
3626 for positioning rehearsal marks on such objects.
3630 @ref{Using the break-alignable-interface}.
3633 @rextend{Callback functions}.
3636 * Setting X-offset and Y-offset directly::
3637 * Using the side-position-interface::
3638 * Using the self-alignment-interface::
3639 * Using the break-alignable-interface::
3642 @node Setting X-offset and Y-offset directly
3643 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
3645 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
3646 properties of many objects. The following example shows three
3647 notes with the default fingering position and the positions with @code{X-offset}
3648 and @code{Y-offset} modified.
3650 @lilypond[verbatim,quote,relative=2]
3657 -\tweak X-offset #-1
3664 @node Using the side-position-interface
3665 @unnumberedsubsubsec Using the @code{side-position-interface}
3667 An object which supports the @code{side-position-interface} can be
3668 placed next to its parent object so that
3669 the specified edges of the two objects touch. The object may be
3670 placed above, below, to the right or to the left of the parent.
3671 The parent cannot be specified; it is determined by the order of
3672 elements in the input stream. Most objects have the associated
3673 note head as their parent.
3675 The values of the @code{side-axis} and @code{direction} properties
3676 determine where the object is to be placed, as follows:
3678 @c TODO add an example of each to the table
3680 @multitable @columnfractions .3 .3 .3
3681 @headitem @code{side-axis} @tab @code{direction} @tab
3682 @headitem property @tab property @tab Placement
3684 @item @code{0} @tab @code{-1} @tab left
3685 @item @code{0} @tab @code{1} @tab right
3686 @item @code{1} @tab @code{-1} @tab below
3687 @item @code{1} @tab @code{1} @tab above
3691 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
3692 the procedure @code{ly:side-position-interface::x-aligned-side}.
3693 This procedure will return the correct value of @code{X-offset} to
3694 place the object to the left or right side of the parent according
3695 to value of @code{direction}.
3697 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3698 the procedure @code{ly:side-position-interface::y-aligned-side}.
3699 This procedure will return the correct value of @code{Y-offset} to
3700 place the object to the top or bottom of the parent according
3701 to value of @code{direction}.
3703 @c TODO Add examples
3705 @node Using the self-alignment-interface
3706 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3708 @subsubsubheading Self-aligning objects horizontally
3710 The horizontal alignment of an object which supports the
3711 @code{self-alignment-interface} is controlled by the value of
3712 the @code{self-alignment-X} property, provided the object's
3713 @code{X-offset} property is set to
3714 @code{ly:self-alignment-interface::x-aligned-on-self}.
3715 @code{self-alignment-X} may be given any
3716 real value, in units of half the total X extent of the
3717 object. Negative values move the object to the right, positive
3718 to the left. A value of @code{0} centers the object on the
3719 reference point of its parent, a value of @w{@code{-1}} aligns the
3720 left edge of the object on the reference point of its parent,
3721 and a value of @code{1} aligns the right edge of the object on the
3722 reference point of its parent. The symbols @code{LEFT},
3723 @code{CENTER}, and @code{RIGHT} may be used instead of the values
3724 @w{@code{-1}}, @code{0}, and @code{1}, respectively.
3726 Normally the @code{\override} command would be used to modify the
3727 value of @code{self-alignment-X}, but the @code{\tweak} command
3728 can be used to separately align several annotations on a single
3731 @lilypond[quote,verbatim,relative=1]
3733 -\tweak self-alignment-X #-1
3735 -\tweak self-alignment-X #0
3737 -\tweak self-alignment-X #RIGHT
3739 -\tweak self-alignment-X #-2.5
3740 ^"aligned further to the right"
3743 @subsubsubheading Self-aligning objects vertically
3745 Objects may be aligned vertically in an analogous way to aligning
3746 them horizontally if the @code{Y-offset} property is set to
3747 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3748 other mechanisms are often involved in vertical alignment: the
3749 value of @code{Y-offset} is just one variable taken into account.
3750 This may make adjusting the value of some objects tricky.
3751 The units are just half the vertical extent of the object, which
3752 is usually quite small, so quite large numbers may be required.
3753 A value of @w{@code{-1}} aligns the lower edge of the object with
3754 the reference point of the parent object, a value of @code{0}
3755 aligns the center of the object with the reference point of the
3756 parent, and a value of @code{1} aligns the top edge of the object
3757 with the reference point of the parent. The symbols @code{DOWN},
3758 @code{CENTER}, and @code{UP} may be substituted for @w{@code{-1}},
3759 @code{0}, and @code{1}, respectively.
3761 @subsubsubheading Self-aligning objects in both directions
3763 By setting both @code{X-offset} and @code{Y-offset}, an object may
3764 be aligned in both directions simultaneously.
3766 The following example shows how to adjust a fingering mark so
3767 that it nestles close to the note head.
3769 @lilypond[quote,verbatim,relative=2]
3771 -\tweak self-alignment-X #0.5 % move horizontally left
3772 -\tweak Y-offset #ly:self-alignment-interface::y-aligned-on-self
3773 -\tweak self-alignment-Y #-1 % move vertically up
3778 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3780 @c Cannot document as they do not seem to operate consistently on all objects -td
3781 @c TODO investigate further
3783 The @code{aligned-on-parent} procedures are used in the same way
3784 as the @code{aligned-on-self} procedures, they difference being
3785 that they permit an object to be aligned with the @emph{edges} of
3786 the parent rather than the parent's reference point. The following
3787 example shows the difference:
3791 @lilypond[verbatim,quote]
3797 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3799 @c Cannot document as they do not seem to operate consistently on all objects -td
3800 @c TODO investigate further
3804 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3806 @node Using the break-alignable-interface
3807 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3809 @cindex align to objects
3810 @cindex break-align-symbols
3812 Rehearsal marks and bar numbers may be aligned with notation
3813 objects other than bar lines. These objects include @code{ambitus},
3814 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3815 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3816 @code{time-signature}.
3818 By default, rehearsal marks and bar numbers will be horizontally
3819 centered above the object:
3821 @lilypond[verbatim,quote,relative=1]
3822 % The rehearsal mark will be centered above the Clef
3823 \override Score.RehearsalMark.break-align-symbols = #'(clef)
3828 % The rehearsal mark will be centered above the Time Signature
3829 \override Score.RehearsalMark.break-align-symbols = #'(time-signature)
3835 % The rehearsal mark will be centered above the Breath Mark
3836 \override Score.RehearsalMark.break-align-symbols = #'(breathing-sign)
3845 A list of possible target alignment objects may be specified. If
3846 some of the objects are invisible at that point due to the setting
3847 of @code{break-visibility} or the explicit visibility settings for
3848 keys and clefs, the rehearsal mark or bar number is aligned to the
3849 first object in the list which is visible. If no objects in the
3850 list are visible the object is aligned to the bar line. If the bar
3851 line is invisible the object is aligned to the place where the bar
3854 @lilypond[verbatim,quote,relative=1]
3855 % The rehearsal mark will be centered above the Key Signature
3856 \override Score.RehearsalMark.break-align-symbols = #'(key-signature clef)
3861 % The rehearsal mark will be centered above the Clef
3862 \set Staff.explicitKeySignatureVisibility = #all-invisible
3863 \override Score.RehearsalMark.break-align-symbols = #'(key-signature clef)
3868 % The rehearsal mark will be centered above the Bar Line
3869 \set Staff.explicitKeySignatureVisibility = #all-invisible
3870 \set Staff.explicitClefVisibility = #all-invisible
3871 \override Score.RehearsalMark.break-align-symbols = #'(key-signature clef)
3878 The alignment of the rehearsal mark relative to the notation object
3879 can be changed, as shown in the following example. In a score with
3880 multiple staves, this setting should be done for all the staves.
3882 @lilypond[verbatim,quote,relative=1]
3883 % The RehearsalMark will be centered above the Key Signature
3884 \override Score.RehearsalMark.break-align-symbols = #'(key-signature)
3890 % The RehearsalMark will be aligned with the left edge of the Key Signature
3891 \once \override Score.KeySignature.break-align-anchor-alignment = #LEFT
3895 % The RehearsalMark will be aligned with the right edge of the Key Signature
3896 \once \override Score.KeySignature.break-align-anchor-alignment = #RIGHT
3902 The rehearsal mark can also be offset to the right or left of the left
3903 edge by an arbitrary amount. The units are staff-spaces:
3905 @lilypond[verbatim,quote,relative=1]
3906 % The RehearsalMark will be aligned with the left edge of the Key Signature
3907 % and then shifted right by 3.5 staff-spaces
3908 \override Score.RehearsalMark.break-align-symbols = #'(key-signature)
3909 \once \override Score.KeySignature.break-align-anchor = #3.5
3913 % The RehearsalMark will be aligned with the left edge of the Key Signature
3914 % and then shifted left by 2 staff-spaces
3915 \once \override Score.KeySignature.break-align-anchor = #-2
3922 @node Vertical grouping of grobs
3923 @subsection Vertical grouping of grobs
3925 @c TODO Expand this section
3927 The VerticalAlignment and VerticalAxisGroup grobs work together.
3928 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3929 etc. VerticalAlignment then vertically aligns the different grobs
3930 grouped together by VerticalAxisGroup. There is usually only one
3931 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3935 @node Modifying stencils
3936 @subsection Modifying stencils
3938 All layout objects have a @code{stencil} property which is part of
3939 the @code{grob-interface}. By default, this property is usually
3940 set to a function specific to the object that is tailor-made to
3941 render the symbol which represents it in the output. For example,
3942 the standard setting for the @code{stencil} property of the
3943 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3945 The standard symbol for any object can be replaced by modifying the
3946 @code{stencil} property to reference a different, specially-written,
3947 procedure. This requires a high level of knowledge of the internal
3948 workings of LilyPond, but there is an easier way which can often
3949 produce adequate results.
3951 This is to set the @code{stencil} property to the procedure which
3952 prints text -- @code{ly:text-interface::print} -- and to add a
3953 @code{text} property to the object which is set to contain the
3954 markup text which produces the required symbol. Due to the
3955 flexibility of markup, much can be achieved -- see in particular
3956 @ref{Graphic notation inside markup}.
3958 The following example demonstrates this by changing the note head
3959 symbol to a cross within a circle.
3961 @lilypond[verbatim,quote]
3963 \once \override NoteHead.stencil = #ly:text-interface::print
3964 \once \override NoteHead.text = \markup {
3966 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3967 \musicglyph #"noteheads.s2cross"
3975 Any of the glyphs in the feta Font can be supplied to the
3976 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3978 @c TODO Add inserting eps files or ref to later
3980 @c TODO Add inserting Postscript or ref to later
3984 @ref{Graphic notation inside markup},
3985 @ref{Formatting text},
3986 @ref{Text markup commands},
3987 @ref{The Feta font}.
3990 @node Modifying shapes
3991 @subsection Modifying shapes
3994 * Modifying ties and slurs::
3997 @node Modifying ties and slurs
3998 @unnumberedsubsubsec Modifying ties and slurs
4000 @cindex slurs, modifying
4001 @cindex ties, modifying
4002 @cindex Bézier curves, control points
4003 @cindex control points, Bézier curves
4005 @code{Tie}s, @code{Slur}s, @code{PhrasingSlur}s,
4006 @code{LaissezVibrerTie}s and @code{RepeatTie}s are all drawn as
4007 third-order Bézier curves. If the shape of the tie or slur which
4008 is calculated automatically is not optimum, the shape may be
4009 modified manually in two ways:
4013 by specifying the displacements to be made to the control points
4014 of the automatically calculated Bézier curve, or
4017 by explicitly specifying the positions of the four control points
4018 required to define the wanted curve.
4021 Both methods are explained below. The first method is more suitable
4022 if only slight adjustments to the curve are required; the second may
4023 be better for creating curves which are related to just a single
4026 @subsubsubheading Cubic Bézier curves
4028 Third-order or cubic Bézier curves are defined by four control
4029 points. The first and fourth control points are precisely the
4030 starting and ending points of the curve. The intermediate two
4031 control points define the shape. Animations showing how the curve
4032 is drawn can be found on the web, but the following description
4033 may be helpful. The curve starts from the first control point
4034 heading directly towards the second, gradually bending over to
4035 head towards the third and continuing to bend over to head towards
4036 the fourth, arriving there travelling directly from the third
4037 control point. The curve is entirely contained in the
4038 quadrilateral defined by the four control points. Translations,
4039 rotations and scaling of the control points all result in exactly
4040 the same operations on the curve.
4042 @subsubsubheading Specifying displacements from current control points
4044 @cindex shaping slurs and ties
4047 In this example the automatic placement of the tie is not optimum,
4048 and @code{\tieDown} would not help.
4050 @lilypond[verbatim,quote,relative=1]
4054 { r4 <g c,> <g c,> <g c,> }
4058 Adjusting the control points of the tie with @code{\shape} allows
4059 the collisions to be avoided.
4061 The syntax of @code{\shape} is
4064 [-]@code{\shape} @var{displacements} @var{item}
4067 This will reposition the control-points of @var{item} by the amounts
4068 given by @var{displacements}. The @var{displacements} argument is a
4069 list of number pairs or a list of such lists. Each element of a pair
4070 represents the displacement of one of the coordinates of a
4071 control-point. If @var{item} is a string, the result is
4072 @code{\once\override} for the specified grob type. If @var{item} is
4073 a music expression, the result is the same music expression with an
4074 appropriate tweak applied.
4076 In other words, the @code{\shape} function can act as either a
4077 @code{\once\override} command or a @code{\tweak} command depending
4078 on whether the @var{item} argument is a grob name, like @qq{Slur},
4079 or a music expression, like @qq{(}. The @var{displacements} argument
4080 specifies the displacements of the four control points as a list of
4081 four pairs of (dx . dy) values in units of staff-spaces (or a list
4082 of such lists if the curve has more than one segment).
4084 The leading hyphen is required if and only if the @code{\tweak} form
4087 So, using the same example as above and the @code{\once\override}
4088 form of @code{\shape}, this will raise the tie by half a staff-space:
4090 @lilypond[verbatim,quote,relative=1]
4093 \shape #'((0 . 0.5) (0 . 0.5) (0 . 0.5) (0 . 0.5)) Tie
4097 { r4 <g c,> <g c,> <g c,> }
4101 This positioning of the tie is better, but maybe it should be raised
4102 more in the center. The following example does this, this time using
4103 the alternative @code{\tweak} form:
4105 @lilypond[verbatim,quote,relative=1]
4108 e1-\shape #'((0 . 0.5) (0 . 1) (0 . 1) (0 . 0.5)) ~ e
4111 { r4 <g c,> <g c,> <g c,> }
4115 Changes to the horizontal positions of the control points may be made
4116 in the same way, and two different curves starting at the same
4117 musical moment may also be shaped:
4119 @lilypond[verbatim,quote,ragged-right,relative=2]
4121 \shape #'((0.7 . -0.4) (0.5 . -0.4) (0.3 . -0.3) (0 . -0.2)) Slur
4122 \shape #'((0 . 0) (0 . 0.5) (0 . 0.5) (0 . 0)) PhrasingSlur
4126 The @code{\shape} function can also displace the control points of
4127 curves which stretch across line breaks. Each piece of the broken
4128 curve can be given its own list of offsets. If changes to a
4129 particular segment are not needed, the empty list can serve as a
4130 placeholder. In this example the line break makes the single slur
4133 @lilypond[verbatim,quote,ragged-right,relative=1]
4139 Changing the shapes of the two halves of the slur makes it clearer
4140 that the slur continues over the line break:
4142 @lilypond[verbatim,quote,ragged-right,relative=1]
4143 % () may be used as a shorthand for ((0 . 0) (0 . 0) (0 . 0) (0 . 0))
4144 % if any of the segments does not need to be changed
4146 (( 0 . 0) (0 . 0) (0 . 0) (0 . 1))
4147 ((0.5 . 1.5) (1 . 0) (0 . 0) (0 . -1.5))
4154 If an S-shaped curve is required the control points must always be
4155 adjusted manually --- LilyPond will never select such shapes
4158 @lilypond[verbatim,quote,relative=2]
4159 c8( e b-> f d' a e-> g)
4160 \shape #'((0 . -1) (5.5 . -0.5) (-5.5 . -10.5) (0 . -5.5)) PhrasingSlur
4161 c8\( e b-> f d' a e-> g\)
4164 @subsubsubheading Specifying control points explicitly
4166 The coordinates of the Bézier control points are specified in units
4167 of staff-spaces. The X@tie{}coordinate is relative to the reference
4168 point of the note to which the tie or slur is attached, and the
4169 Y@tie{}coordinate is relative to the staff center line. The
4170 coordinates are specified as a list of four pairs of decimal numbers
4171 (reals). One approach is to estimate the coordinates of the two
4172 end points, and then guess the two intermediate points. The optimum
4173 values are then found by trial and error. Be aware that these values
4174 may need to be manually adjusted if any further changes are made to
4175 the music or the layout.
4177 One situation where specifying the control points explicitly is
4178 preferable to specifying displacements is when they need to be
4179 specified relative to a single note. Here is an example of this.
4180 It shows one way of indicating a slur extending into alternative
4181 sections of a volta repeat.
4183 @lilypond[verbatim,quote,relative=2]
4185 \repeat volta 3 { c4 d( e f }
4190 % create a slur and move it to a new position
4191 % the <> is just an empty chord to carry the slur termination
4192 -\tweak control-points #'((-2 . 3.8) (-1 . 3.9) (0 . 4) (1 . 3.4)) ( <> )
4197 % create a slur and move it to a new position
4198 -\tweak control-points #'((-2 . 3) (-1 . 3.1) (0 . 3.2) (1 . 2.4)) ( <> )
4205 It is not possible to modify shapes of ties or slurs by changing
4206 the @code{control-points} property if there are multiple ties or slurs
4207 at the same musical moment -- the @code{\tweak} command will also not
4208 work in this case. However, the @code{tie-configuration} property of
4209 @code{TieColumn} can be overridden to set start line and direction as
4213 Internals Reference:
4214 @rinternals{TieColumn}.
4216 @cindex Scheme, pure containers
4217 @cindex Scheme, unpure containers
4218 @cindex pure containers, Scheme
4219 @cindex unpure containers, Scheme
4220 @cindex horizontal spacing, overriding
4223 @node Unpure-pure containers
4224 @subsection Unpure-pure containers
4226 Unpure-pure containers are useful for overriding @emph{Y-axis} spacing
4227 calculations - specifically @code{Y-offset} and @code{Y-extent} - with a
4228 Scheme function instead of a literal (i.e. a number or pair).
4230 For certain grobs, the @code{Y-extent} is based on the @code{stencil}
4231 property, overriding the stencil property of one of these will
4232 require an additional @code{Y-extent} override with an unpure-pure
4233 container. When a function overrides a @code{Y-offset} and/or
4234 @code{Y-extent} it is assumed that this will trigger line breaking
4235 calculations too early during compilation. So the function is not
4236 evaluated at all (usually returning a value of @samp{0} or
4237 @samp{'(0 . 0)}) which can result in collisions. A @q{pure} function
4238 will not affect properties, objects or grob suicides and therefore will
4239 always have its Y-axis-related evaluated correctly.
4241 Currently, there are about thirty functions that are already considered
4242 @q{pure} and Unpure-pure containers are a way to set functions not on
4243 this list as @q{pure}. The @q{pure} function is evaluated @emph{before}
4244 any line-breaking and so the horizontal spacing can be adjusted
4245 @q{in time}. The @q{unpure} function is then evaluated @emph{after}
4248 @warning{As it is difficult to always know which functions are on this
4249 list we recommend that any @q{pure} functions you create do not use
4250 @code{Beam} or @code{VerticalAlignment} grobs.}
4252 An unpure-pure container is constructed as follows;
4254 @code{(ly:make-unpure-pure-container f0 f1)}
4256 where @code{f0} is a function taking @var{n} arguments (@var{n >= 1})
4257 and the first argument must always be the grob. This is the function
4258 that gives the actual result. @var{f1} is the function being labeled
4259 as @q{pure} that takes @var{n + 2} arguments. Again, the first argument
4260 must always still be the grob but the second and third are @q{start}
4261 and @q{end} arguments.
4263 @var{start} and @var{end} are, for all intents and purposes, dummy
4264 values that only matter for @code{Spanners} (i.e @code{Hairpin} or
4265 @code{Beam}), that can return different height estimations based on a
4266 starting and ending column.
4268 The rest are the other arguments to the first function (which
4269 may be none if @var{n = 1}).
4271 The results of the second function are used as an approximation of the
4272 value needed which is then used by the first function to get the real
4273 value which is then used for fine-tuning much later during the spacing
4276 @lilypond[verbatim,quote,ragged-right]
4277 #(define (square-line-circle-space grob)
4278 (let* ((pitch (ly:event-property (ly:grob-property grob 'cause) 'pitch))
4279 (notename (ly:pitch-notename pitch)))
4280 (if (= 0 (modulo notename 2))
4281 (make-circle-stencil 0.5 0.0 #t)
4282 (make-filled-box-stencil '(0 . 1.0)
4285 squareLineCircleSpace = {
4286 \override NoteHead.stencil = #square-line-circle-space
4289 smartSquareLineCircleSpace = {
4290 \squareLineCircleSpace
4291 \override NoteHead.Y-extent =
4292 #(ly:make-unpure-pure-container
4293 ly:grob::stencil-height
4294 (lambda (grob start end) (ly:grob::stencil-height grob)))
4297 \new Voice \with { \remove "Stem_engraver" }
4299 \squareLineCircleSpace
4301 \smartSquareLineCircleSpace
4306 In the first measure, without the unpure-pure container, the spacing
4307 engine does not know the width of the note head and lets it collide with
4308 the accidentals. In the second measure, with unpure-pure containers,
4309 the spacing engine knows the width of the note heads and avoids the
4310 collision by lengthening the line accordingly.
4312 Usually for simple calculations nearly-identical functions for both the
4313 @q{unpure} and @q{pure} parts can be used, by only changing the number
4314 of arguments passed to, and the scope of, the function.
4316 @warning{If a function is labeled as @q{pure} and it turns out not to
4317 be, the results can be unexpected.}
4320 @node Using music functions
4321 @section Using music functions
4323 @c TODO -- add @seealso, etc. to these subsections
4325 Where tweaks need to be reused with different music expressions,
4326 it is often convenient to make the tweak part of a @emph{music
4327 function}. In this section, we discuss only @emph{substitution}
4328 functions, where the object is to substitute a variable into a
4329 piece of LilyPond input code. Other more complex functions are
4330 described in @rextend{Music functions}.
4333 * Substitution function syntax::
4334 * Substitution function examples::
4337 @node Substitution function syntax
4338 @subsection Substitution function syntax
4340 Making a function that substitutes a variable into LilyPond
4341 code is easy. The general form of these functions is
4345 #(define-music-function
4346 (parser location @var{arg1} @var{arg2} @dots{})
4347 (@var{type1?} @var{type2?} @dots{})
4349 @var{@dots{}music@dots{}}
4356 @multitable @columnfractions .33 .66
4357 @item @code{@var{argN}}
4358 @tab @var{n}th argument
4360 @item @code{@var{typeN?}}
4361 @tab a scheme @emph{type predicate} for which @code{@var{argN}}
4362 must return @code{#t}.
4364 @item @code{@var{@dots{}music@dots{}}}
4365 @tab normal LilyPond input, using @code{$} (in places where only
4366 Lilypond constructs are allowed) or @code{#} (to use it as a Scheme
4367 value or music function argument or music inside of music lists) to
4372 The @code{parser} and @code{location} arguments are mandatory, and
4373 are used in some advanced situations as described in the
4374 @q{Extending} manual (see @rextend{Music functions}). For
4375 substitution functions, just be sure to include them.
4377 The list of type predicates is also required. Some of the most
4378 common type predicates used in music functions are:
4382 cheap-list? @emph{(use instead of }@q{list?}@emph{ for faster processing)}
4394 For a list of available type predicates, see
4395 @ref{Predefined type predicates}. User-defined type predicates
4400 @ref{Predefined type predicates}.
4403 @rextend{Music functions}.
4406 @file{lily/music-scheme.cc},
4408 @file{scm/lily.scm}.
4411 @node Substitution function examples
4412 @subsection Substitution function examples
4414 This section introduces some substitution function examples.
4415 These are not intended to be exhaustive, but rather to demonstrate
4416 some of the possibilities of simple substitution functions.
4418 In the first example, a function is defined that simplifies
4419 setting the padding of a TextScript:
4421 @lilypond[quote,verbatim,ragged-right]
4423 #(define-music-function
4424 (parser location padding)
4427 \once \override TextScript.padding = #padding
4431 c4^"piu mosso" b a b
4433 c4^"piu mosso" d e f
4435 c4^"piu mosso" fis a g
4439 In addition to numbers, we can use music expressions such
4440 as notes for arguments to music functions:
4442 @lilypond[quote,verbatim,ragged-right]
4444 #(define-music-function
4445 (parser location note)
4448 \tweak NoteHead.stencil #ly:text-interface::print
4449 \tweak NoteHead.text
4450 \markup \musicglyph #"custodes.mensural.u0"
4451 \tweak Stem.stencil ##f
4455 \relative c' { c4 d e f \custosNote g }
4458 Substitution functions with multiple arguments can be defined:
4460 @lilypond[quote,verbatim,ragged-right]
4462 #(define-music-function
4463 (parser location padding tempotext)
4466 \once \override Score.MetronomeMark.padding = #padding
4467 \tempo \markup { \bold #tempotext }
4471 \tempo \markup { "Low tempo" }
4473 \tempoPadded #4.0 "High tempo"
4478 @c TODO: add appropriate @@ref's here.