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13 @node Changing defaults
14 @chapter Changing defaults
16 The purpose of LilyPond's design is to provide the finest quality
17 output by default. Nevertheless, it may happen that you need to
18 change this default layout. The layout is controlled through a large
19 number of @q{knobs and switches} collectively called @q{properties}.
20 A tutorial introduction to accessing and modifying these properties
21 can be found in the Learning Manual, see @rlearning{Tweaking output}.
22 This should be read first. This chapter covers similar ground, but
23 in a style more appropriate to a reference manual.
25 @cindex Internals Reference
27 The definitive description of the controls available for tuning can
28 be found in a separate document: @rinternalsnamed{Top,the Internals
29 Reference}. That manual lists all the variables, functions and
30 options available in LilyPond. It is written as a HTML document,
32 @c leave the @uref as one long line.
33 @uref{http://@/lilypond@/.org/@/doc/@/stable/@/Documentation/@/user/@/lilypond@/-internals/,on@/-line},
34 and is also included with the LilyPond documentation package.
36 Internally, LilyPond uses Scheme (a LISP dialect) to provide
37 infrastructure. Overriding layout decisions in effect accesses the
38 program internals, which requires Scheme input. Scheme elements are
39 introduced in a @file{.ly} file with the hash
40 mark@tie{}@code{#}.@footnote{@rextend{Scheme tutorial}, contains a
41 short tutorial on entering numbers, lists, strings, and symbols in
46 * Interpretation contexts::
47 * Explaining the Internals Reference::
48 * Modifying properties::
49 * Useful concepts and properties::
51 * Using music functions::
55 @node Interpretation contexts
56 @section Interpretation contexts
58 This section describes what contexts are, and how to modify them.
61 * Contexts explained::
63 * Keeping contexts alive::
64 * Modifying context plug-ins::
65 * Changing context default settings::
66 * Defining new contexts::
73 @rlearning{Contexts and engravers}.
76 @file{ly/engraver-init.ly},
77 @file{ly/performer-init.ly}.
80 @rlsr{Contexts and engravers}.
83 @rinternals{Contexts},
84 @rinternals{Engravers and Performers}.
87 @node Contexts explained
88 @subsection Contexts explained
91 @c TODO Rethink and rewrite
93 >> > > - list of contexts: my *danger unmaintainable*
94 >> > > alarm just went off. I'm
96 I knew it would... And leaving out some of them is perfectly fine
98 I do think that a list like this, with the main contexts and a
100 description of what they do (perhaps also with a note about what
102 behavior is associated with each of them, but this may be
104 should be there, and then we could simply list the remaining ones
106 further explanation and with links to the IR.
109 @c TODO Improve layout, order and consistency of wording -td
111 @c TODO Add introduction which explains contexts in generality -td
113 @c TODO Describe propagation of property values -td
115 Contexts are arranged hierarchically:
118 * Score - the master of all contexts::
119 * Top-level contexts - staff containers::
120 * Intermediate-level contexts - staves::
121 * Bottom-level contexts - voices::
124 @node Score - the master of all contexts
125 @unnumberedsubsubsec Score - the master of all contexts
127 This is the top level notation context. No other context can
128 contain a Score context. By default the Score context handles
129 the administration of time signatures and makes sure that items
130 such as clefs, time signatures, and key-signatures are aligned
133 A Score context is instantiated implicitly when a
134 @code{\score @{@dots{}@}} or @code{\layout @{@dots{}@}} block is
137 @node Top-level contexts - staff containers
138 @unnumberedsubsubsec Top-level contexts - staff containers
140 @strong{@emph{StaffGroup}}
142 Groups staves while adding a bracket on the left side, grouping
143 the staves together. The bar lines of the contained staves are
144 connected vertically. @code{StaffGroup} only consists of a collection
145 of staves, with a bracket in front and spanning bar lines.
147 @strong{@emph{ChoirStaff}}
149 Identical to @code{StaffGroup} except that the bar lines of the
150 contained staves are not connected vertically.
152 @strong{@emph{GrandStaff}}
154 A group of staves, with a brace on the left side, grouping the
155 staves together. The bar lines of the contained staves are
156 connected vertically.
158 @strong{@emph{PianoStaff}}
160 Just like @code{GrandStaff}, but with support for instrument names
161 to the left of each system.
163 @node Intermediate-level contexts - staves
164 @unnumberedsubsubsec Intermediate-level contexts - staves
166 @strong{@emph{Staff}}
168 Handles clefs, bar lines, keys, accidentals. It can contain
169 @code{Voice} contexts.
171 @strong{@emph{RhythmicStaff}}
173 Like @code{Staff} but for printing rhythms. Pitches are ignored;
174 the notes are printed on one line.
176 @strong{@emph{TabStaff}}
178 Context for generating tablature. By default lays the music
179 expression out as a guitar tablature, printed on six lines.
181 @strong{@emph{DrumStaff}}
183 Handles typesetting for percussion. Can contain @code{DrumVoice}
185 @strong{@emph{VaticanaStaff}}
187 Same as @code{Staff}, except that it is designed for typesetting
188 a piece in gregorian style.
190 @strong{@emph{MensuralStaff}}
192 Same as @code{Staff}, except that it is designed for typesetting
193 a piece in mensural style.
195 @node Bottom-level contexts - voices
196 @unnumberedsubsubsec Bottom-level contexts - voices
198 Voice-level contexts initialise certain properties and start
199 appropriate engravers. Being bottom-level contexts, they cannot
200 contain other contexts.
202 @strong{@emph{Voice}}
204 Corresponds to a voice on a staff. This context handles the
205 conversion of dynamic signs, stems, beams, super- and sub-scripts,
206 slurs, ties, and rests. You have to instantiate this explicitly
207 if you require multiple voices on the same staff.
209 @strong{@emph{VaticanaVoice}}
211 Same as @code{Voice}, except that it is designed for typesetting
212 a piece in gregorian style.
214 @strong{@emph{MensuralVoice}}
216 Same as @code{Voice}, with modifications for typesetting a piece in
219 @strong{@emph{Lyrics}}
221 Corresponds to a voice with lyrics. Handles the printing of a
222 single line of lyrics.
224 @strong{@emph{DrumVoice}}
226 The voice context used in a percussion staff.
228 @strong{@emph{FiguredBass}}
230 The context in which @code{BassFigure} objects are created from
231 input entered in @code{\figuremode} mode.
233 @strong{@emph{TabVoice}}
235 The voice context used within a @code{TabStaff} context. Usually
236 left to be created implicitly.
238 @strong{@emph{CueVoice}}
240 A voice context used to render notes of a reduced size, intended
241 primarily for adding cue notes to a staff, see @ref{Formatting
242 cue notes}. Usually left to be created implicitly.
244 @strong{@emph{ChordNames}}
246 Typesets chord names.
251 Then the following, which I don't know what to do with:
253 * GregorianTranscriptionVoice
254 * GregorianTranscriptionStaff
257 Engraves fretboards from chords. Not easy... Not
259 There is now some documentation on FretBoards in the NR, under
260 instrument-specific notation -- cds.
265 Hard coded entry point for LilyPond. Cannot be tuned.
267 Silently discards all musical information given to this
272 @node Creating contexts
273 @subsection Creating contexts
275 @c TODO more complete descriptions rather than learning style
277 For scores with only one voice and one staff, contexts are
278 created automatically. For more complex scores, it is necessary to
279 create them by hand. There are three commands that do this.
284 The easiest command is @code{\new}, and it also the quickest to type.
285 It is prepended to a music expression, for example
289 @cindex Context, creating
292 \new @var{type} @var{music expression}
296 where @var{type} is a context name (like @code{Staff} or
297 @code{Voice}). This command creates a new context, and starts
298 interpreting the @var{music expression} with that.
300 A practical application of @code{\new} is a score with many
301 staves. Each part that should be on its own staff, is preceded with
304 @lilypond[quote,verbatim,relative=2,ragged-right]
311 The @code{\new} command may also give a name to the context,
314 \new @var{type} = @var{id} @var{music}
316 However, this user specified name is only used if there is no other
317 context already earlier with the same name.
323 Like @code{\new}, the @code{\context} command also directs a music
324 expression to a context object, but gives the context an explicit name. The
328 \context @var{type} = @var{id} @var{music}
331 This form will search for an existing context of type @var{type}
332 called @var{id}. If that context does not exist yet, a new
333 context with the specified name is created. This is useful if
334 the context is referred to later on. For example, when
335 setting lyrics the melody is in a named context
338 \context Voice = "@b{tenor}" @var{music}
342 so the texts can be properly aligned to its notes,
345 \new Lyrics \lyricsto "@b{tenor}" @var{lyrics}
350 Another possible use of named contexts is funneling two different
351 music expressions into one context. In the following example,
352 articulations and notes are entered separately,
356 arts = @{ s4-. s4-> @}
359 They are combined by sending both to the same @code{Voice} context,
363 \new Staff \context Voice = "A" \music
364 \context Voice = "A" \arts
367 @lilypond[quote,ragged-right]
371 \new Staff \context Voice = "A" \music
372 \context Voice = "A" \arts
376 With this mechanism, it is possible to define an Urtext (original
377 edition), with the option to put several distinct articulations on the
380 @cindex creating contexts
383 The third command for creating contexts is
385 \context @var{type} @var{music}
390 This is similar to @code{\context} with @code{= @var{id}}, but matches
391 any context of type @var{type}, regardless of its given name.
393 This variant is used with music expressions that can be interpreted at
394 several levels. For example, the @code{\applyOutput} command (see
395 @rextend{Running a function on all layout objects}). Without an explicit
396 @code{\context}, it is usually applied to @code{Voice}
399 \applyOutput #'@var{context} #@var{function} % apply to Voice
402 To have it interpreted at the @code{Score} or @code{Staff} level use
406 \applyOutput #'Score #@var{function}
407 \applyOutput #'Staff #@var{function}
412 @node Keeping contexts alive
413 @subsection Keeping contexts alive
415 @cindex contexts, keeping alive
416 @cindex contexts, lifetime
418 Contexts are usually terminated at the first musical moment in
419 which they have nothing to do. So @code{Voice} contexts die as
420 soon as they contain no events; @code{Staff} contexts die as soon
421 as all the @code{Voice} contexts within them contain no events; etc.
422 This can cause difficulties if earlier contexts which have died
423 have to be referenced, for example, when changing staves with
424 @code{\change} commands, associating lyrics with a voice with
425 @code{\lyricsto} commands, or when adding further musical events to
428 There is an exception to this general rule: just one of the
429 @code{Voice} contexts in a @code{Staff} context or in a
430 @code{<<...>>} construct will always persist to the end of the
431 enclosing @code{Staff} context or @code{<<...>>} construct, even
432 though there may be periods when it has nothing to do. The context
433 to persist in this way will be the first one encountered in the
434 first enclosed @code{@{...@}} construct, ignoring any in enclosed
435 @code{<<...>>} constructs.
437 Any context can be kept alive by ensuring it has something to do at
438 every musical moment. @code{Staff} contexts are kept alive by
439 ensuring one of their voices is kept alive. One way of doing this
440 is to add spacer rests to a voice in parallel with the real music.
441 These need to be added to every @code{Voice} context which needs to
442 be kept alive. If several voices are to be used sporadically it is
443 safest to keep them all alive rather than attempting to rely on the
444 exceptions mentioned above.
446 In the following example, both voice A and voice B are kept alive
447 in this way for the duration of the piece:
449 @lilypond[quote,verbatim]
450 musicA = \relative c'' { d4 d d d }
451 musicB = \relative c'' { g4 g g g }
454 \new Voice = "A" { s1*5 } % Keep Voice "A" alive for 5 bars
455 \new Voice = "B" { s1*5 } % Keep Voice "B" alive for 5 bars
460 \context Voice = "A" {
464 \context Voice = "B" {
468 \context Voice = "A" { \musicA }
469 \context Voice = "B" { \musicB }
470 \context Voice = "A" { \musicA }
481 @cindex lyrics, aligning with sporadic melody
483 The following example shows how a sporadic melody line with lyrics
484 might be written using this approach. In a real situation the
485 melody and accompaniment would consist of several different
488 @lilypond[quote,verbatim]
489 melody = \relative c'' { a4 a a a }
490 accompaniment = \relative c' { d4 d d d }
491 words = \lyricmode { These words fol -- low the mel -- o -- dy }
494 \new Staff = "music" {
496 \new Voice = "melody" {
498 s1*4 % Keep Voice "melody" alive for 4 bars
501 \new Voice = "accompaniment" {
506 \context Voice = "melody" { \melody }
507 \context Voice = "accompaniment" { \accompaniment }
509 \context Voice = "accompaniment" { \accompaniment }
511 \context Voice = "melody" { \melody }
512 \context Voice = "accompaniment" { \accompaniment }
517 \new Lyrics \with { alignAboveContext = #"music" }
518 \lyricsto "melody" { \words }
523 An alternative way, which may be better in many circumstances, is
524 to keep the melody line alive by simply including spacer notes to
525 line it up correctly with the accompaniment:
527 @lilypond[quote,verbatim]
528 melody = \relative c'' {
534 accompaniment = \relative c' {
540 words = \lyricmode { These words fol -- low the mel -- o -- dy }
544 \new Staff = "music" {
546 \new Voice = "melody" {
550 \new Voice = "accompaniment" {
556 \new Lyrics \with { alignAboveContext = #"music" }
557 \lyricsto "melody" { \words }
563 @node Modifying context plug-ins
564 @subsection Modifying context plug-ins
566 @c TODO Should this be Modifying engravers or Modifying contexts?
568 Notation contexts (like @code{Score} and @code{Staff}) not only
570 they also contain plug-ins called @q{engravers} that create notation
571 elements. For example, the @code{Voice} context contains a
572 @code{Note_heads_engraver} and the @code{Staff} context contains a
573 @code{Key_signature_engraver}.
575 For a full a description of each plug-in, see
577 @rinternals{Engravers and Performers}.
580 Internals Reference @expansion{} Translation @expansion{} Engravers.
582 Every context described in
584 @rinternals{Contexts}
587 Internals Reference @expansion{} Translation @expansion{} Context.
589 lists the engravers used for that context.
592 It can be useful to shuffle around these plug-ins. This is done by
593 starting a new context with @code{\new} or @code{\context}, and
599 \new @var{context} \with @{
612 where the @dots{} should be the name of an engraver. Here is a simple
613 example which removes @code{Time_signature_engraver} and
614 @code{Clef_engraver} from a @code{Staff} context,
616 @lilypond[quote,relative=1,verbatim]
622 \remove "Time_signature_engraver"
623 \remove "Clef_engraver"
630 In the second staff there are no time signature or clef symbols. This
631 is a rather crude method of making objects disappear since it will affect
632 the entire staff. This method also influences the spacing, which may or
633 may not be desirable. More sophisticated methods of blanking objects
634 are shown in @rlearning{Visibility and color of objects}.
636 The next example shows a practical application. Bar lines and time
637 signatures are normally synchronized across the score. This is done
638 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
639 This plug-in keeps an administration of time signature, location
640 within the measure, etc. By moving these engraver from @code{Score} to
641 @code{Staff} context, we can have a score where each staff has its own
644 @cindex polymetric scores
645 @cindex Time signatures, multiple
647 @lilypond[quote,verbatim]
651 \consists "Timing_translator"
652 \consists "Default_bar_line_engraver"
658 \consists "Timing_translator"
659 \consists "Default_bar_line_engraver"
668 \remove "Timing_translator"
669 \remove "Default_bar_line_engraver"
677 Usually the order in which the engravers are specified
678 does not matter, but in a few special cases the order
679 is important, for example where one engraver writes
680 a property and another reads it, or where one engraver
681 creates a grob and another must process it. The order in
682 which the engravers are specified is the order in which
683 they are called to carry out their processing.
685 The following orderings are important: the
686 @code{Bar_engraver} must normally be first, and
687 the @code{New_fingering_engraver} must come before
688 the @code{Script_column_engraver}. There may be others
689 with ordering dependencies.
691 @node Changing context default settings
692 @subsection Changing context default settings
694 The context settings which are to be used by default in
695 @code{Score}, @code{Staff} and @code{Voice} contexts may be specified
696 in a @code{\layout} block, as illustrated in the following example.
697 The @code{\layout} block should be placed within the @code{\score}
698 block to which it is to apply, but outside any music.
700 Note that the @code{\set} command itself and the context must be
701 omitted when the context default values are specified in this way:
703 @lilypond[quote,verbatim]
706 a4^"Really small, thicker stems, no time signature" a a a
713 \override Stem #'thickness = #4.0
714 \remove "Time_signature_engraver"
720 In this example, the @code{\Staff} command specifies that the
721 subsequent specifications are to be applied to all staves within
724 Modifications can be made to the @code{Score} context or all
725 @code{Voice} contexts in a similar way.
729 It is not possible to collect context changes in a variable and apply
730 them to a @code{\context} definition by referring to that variable.
732 The @code{\Staff \RemoveEmptyStaves} will overwrite your current
733 @code{\Staff} settings. If you wish to change the defaults for a
734 staff which uses @code{\Staff \RemoveEmptyStaves}, you must do so
735 after calling @code{\Staff \RemoveEmptyStaves}, ie
740 \Staff \RemoveEmptyStaves
742 \override Stem #'thickness = #4.0
747 @c TODO: add \with in here.
751 @node Defining new contexts
752 @subsection Defining new contexts
754 @cindex contexts, defining new
755 @cindex engravers, including in contexts
770 Specific contexts, like @code{Staff} and @code{Voice}, are made of
771 simple building blocks. It is possible to create new types of
772 contexts with different combinations of engraver plug-ins.
774 The next example shows how to build a different type of
775 @code{Voice} context from scratch. It will be similar to
776 @code{Voice}, but only prints centered slash note heads. It can be used
777 to indicate improvisation in jazz pieces,
779 @lilypond[quote,ragged-right]
782 \type "Engraver_group"
783 \consists "Note_heads_engraver"
784 \consists "Rhythmic_column_engraver"
785 \consists "Text_engraver"
786 \consists Pitch_squash_engraver
787 squashedPosition = #0
788 \override NoteHead #'style = #'slash
789 \override Stem #'transparent = ##t
793 \accepts "ImproVoice"
797 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
798 c4 c^"undress" c_"while playing :)" c }
804 These settings are defined within a @code{\context} block inside a
805 @code{\layout} block,
815 In the following discussion, the example input shown should go in place
816 of the @dots{} in the previous fragment.
818 First it is necessary to define a name for the new context:
824 Since it is similar to the @code{Voice}, we want commands that work
825 on (existing) @code{Voice}s to remain working. This is achieved by
826 giving the new context an alias @code{Voice},
832 The context will print notes and instructive texts, so we need to add
833 the engravers which provide this functionality,
836 \consists Note_heads_engraver
837 \consists Text_engraver
840 but we only need this on the center line,
843 \consists Pitch_squash_engraver
844 squashedPosition = #0
847 The @rinternals{Pitch_squash_engraver} modifies note heads (created
848 by @rinternals{Note_heads_engraver}) and sets their vertical
849 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
852 The notes look like a slash, and have no stem,
855 \override NoteHead #'style = #'slash
856 \override Stem #'transparent = ##t
859 All these plug-ins have to cooperate, and this is achieved with a
860 special plug-in, which must be marked with the keyword @code{\type}.
861 This should always be @code{Engraver_group}.
864 \type "Engraver_group"
872 \type "Engraver_group"
873 \consists "Note_heads_engraver"
874 \consists "Text_engraver"
875 \consists Pitch_squash_engraver
876 squashedPosition = #0
877 \override NoteHead #'style = #'slash
878 \override Stem #'transparent = ##t
884 Contexts form hierarchies. We want to hang the @code{ImproVoice}
885 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
886 modify the @code{Staff} definition with the @code{\accepts}
897 The opposite of @code{\accepts} is @code{\denies},
898 which is sometimes needed when reusing existing context definitions.
900 Putting both into a @code{\layout} block, like
910 \accepts "ImproVoice"
915 Then the output at the start of this subsection can be entered as
923 c c_"while playing :)"
930 @node Aligning contexts
931 @subsection Aligning contexts
933 New contexts may be aligned above or below existing contexts. This
934 could be useful in setting up a vocal staff (@rlearning{Vocal ensembles}) and
937 @c TODO Better example needed. Ref LM, and expand on it.
940 @funindex alignAboveContext
941 @funindex alignBelowContext
943 @lilypond[quote,ragged-right]
946 \relative c' \new Staff = "main" {
949 \new Staff \with { alignAboveContext = #"main" } \ossia
956 @cindex nested contexts
957 @cindex contexts, nested
962 Contexts like @code{PianoStaff} can contain other contexts
963 nested within them. Contexts which are acceptable for nesting
964 are defined by the @qq{accepts} list of a context. Contexts
965 which are not in this list are placed below the outer context
966 in the printed score.
967 For example, the @code{PianoStaff} context is defined by default
968 to accept @code{Staff} and @code{FiguredBass} contexts within
969 it, but not (for example) a @code{Lyrics} context. So in the
970 following structure the lyrics are placed below the piano staff
971 rather than between the two staves:
973 @lilypond[verbatim,quote,relative=1]
976 \new Staff { e4 d c2 }
977 \addlyrics { Three blind mice }
985 The @qq{accepts} list of a context can be modified to include
986 additional nested contexts, so if we wanted the lyrics to appear
987 between the two staves we could use:
989 @lilypond[verbatim,quote,relative=1]
990 \new PianoStaff \with { \accepts Lyrics }
992 \new Staff { e4 d c2 }
993 \addlyrics { Three blind mice }
1001 The opposite of @code{\accepts} is @code{\denies}; this removes a
1002 context from the @qq{accepts} list.
1004 @node Explaining the Internals Reference
1005 @section Explaining the Internals Reference
1009 * Navigating the program reference::
1010 * Layout interfaces::
1011 * Determining the grob property::
1012 * Naming conventions::
1015 @node Navigating the program reference
1016 @subsection Navigating the program reference
1018 @c TODO remove this (it's in the LM)
1019 @c Replace with more factual directions
1021 Suppose we want to move the fingering indication in the fragment
1024 @lilypond[quote,relative=2,verbatim]
1030 If you visit the documentation on fingering instructions (in
1031 @ref{Fingering instructions}), you will notice:
1036 Internals Reference: @rinternals{Fingering}.
1041 @c outdated info; probably will delete.
1043 This fragment points to two parts of the program reference: a page
1044 on @code{FingeringEvent} and one on @code{Fingering}.
1046 The page on @code{FingeringEvent} describes the properties of the music
1047 expression for the input @w{@code{-2}}. The page contains many links
1048 forward. For example, it says
1051 Accepted by: @rinternals{Fingering_engraver},
1055 That link brings us to the documentation for the Engraver, the
1059 This engraver creates the following layout objects: @rinternals{Fingering}.
1062 In other words, once the @code{FingeringEvent}s are interpreted, the
1063 @code{Fingering_engraver} plug-in will process them.
1067 @c I can't figure out what this is supposed to mean. -gp
1069 The @code{Fingering_engraver} is also listed to create
1070 @rinternals{Fingering} objects,
1072 @c old info? it doesn't make any sense to me with our current docs.
1074 second bit of information listed under @b{See also} in the Notation
1079 The programmer's reference is available as an HTML document. It is
1080 highly recommended that you read it in HTML form, either online or
1081 by downloading the HTML documentation. This section will be much more
1082 difficult to understand if you are using the
1086 Follow the link to @rinternals{Fingering}. At the top of the
1090 Fingering objects are created by: @rinternals{Fingering_engraver} and
1091 @rinternals{New_fingering_engraver}.
1094 By following related links inside the program reference, we can follow the
1095 flow of information within the program:
1099 @item @rinternals{Fingering}:
1100 @rinternals{Fingering} objects are created by:
1101 @rinternals{Fingering_engraver}
1103 @item @rinternals{Fingering_engraver}:
1104 Music types accepted: @rinternals{fingering-event}
1106 @item @rinternals{fingering-event}:
1107 Music event type @code{fingering-event} is in Music expressions named
1108 @rinternals{FingeringEvent}
1111 This path goes against the flow of information in the program: it
1112 starts from the output, and ends at the input event. You could
1113 also start at an input event, and read with the flow of
1114 information, eventually ending up at the output object(s).
1116 The program reference can also be browsed like a normal document. It
1117 contains chapters on
1119 @rinternals{Music definitions},
1122 @code{Music definitions}
1124 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1125 chapter lists all the definitions used and all properties that may be
1129 @node Layout interfaces
1130 @subsection Layout interfaces
1132 @cindex interface, layout
1133 @cindex layout interface
1136 The HTML page that we found in the previous section describes the
1137 layout object called @rinternals{Fingering}. Such an object is a
1138 symbol within the score. It has properties that store numbers (like
1139 thicknesses and directions), but also pointers to related objects. A
1140 layout object is also called a @emph{Grob}, which is short for Graphical
1141 Object. For more details about Grobs, see @rinternals{grob-interface}.
1143 The page for @code{Fingering} lists the definitions for the
1144 @code{Fingering} object. For example, the page says
1147 @code{padding} (dimension, in staff space):
1153 which means that the number will be kept at a distance of at least 0.5
1157 Each layout object may have several functions as a notational or
1158 typographical element. For example, the Fingering object
1159 has the following aspects
1163 Its size is independent of the horizontal spacing, unlike slurs or beams.
1166 It is a piece of text. Granted, it is usually a very short text.
1169 That piece of text is typeset with a font, unlike slurs or beams.
1172 Horizontally, the center of the symbol should be aligned to the
1173 center of the note head.
1176 Vertically, the symbol is placed next to the note and the staff.
1179 The vertical position is also coordinated with other superscript
1180 and subscript symbols.
1183 Each of these aspects is captured in so-called @emph{interface}s,
1184 which are listed on the @rinternals{Fingering} page at the bottom
1187 This object supports the following interfaces:
1188 @rinternals{item-interface},
1189 @rinternals{self-alignment-interface},
1190 @rinternals{side-position-interface}, @rinternals{text-interface},
1191 @rinternals{text-script-interface}, @rinternals{font-interface},
1192 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1195 Clicking any of the links will take you to the page of the respective
1196 object interface. Each interface has a number of properties. Some of
1197 them are not user-serviceable (@q{Internal properties}), but others
1200 We have been talking of @emph{the} @code{Fingering} object, but actually it
1201 does not amount to much. The initialization file (see
1202 @rlearning{Other sources of information})
1203 @file{scm/define-grobs.scm} shows the soul of the @q{object},
1208 (avoid-slur . around)
1209 (slur-padding . 0.2)
1210 (staff-padding . 0.5)
1211 (self-alignment-X . 0)
1212 (self-alignment-Y . 0)
1213 (script-priority . 100)
1214 (stencil . ,ly:text-interface::print)
1215 (direction . ,ly:script-interface::calc-direction)
1216 (font-encoding . fetaText)
1217 (font-size . -5) ; don't overlap when next to heads.
1218 (meta . ((class . Item)
1219 (interfaces . (finger-interface
1221 text-script-interface
1223 side-position-interface
1224 self-alignment-interface
1225 item-interface))))))
1229 As you can see, the @code{Fingering} object is nothing more than a
1230 bunch of variable settings, and the webpage in the Internals Reference
1231 is directly generated from this definition.
1234 @node Determining the grob property
1235 @subsection Determining the grob property
1237 @c TODO remove this (it's in the LM)
1238 @c Replace with more factual directions
1240 Recall that we wanted to change the position of the @b{2} in
1242 @lilypond[quote,relative=2,verbatim]
1248 Since the @b{2} is vertically positioned next to its note, we have to
1249 meddle with the interface associated with this positioning. This is
1250 done using @code{side-position-interface}. The page for this interface
1254 @code{side-position-interface}
1256 Position a victim object (this one) next to other objects (the
1257 support). The property @code{direction} signifies where to put the
1258 victim object relative to the support (left or right, up or down?)
1263 Below this description, the variable @code{padding} is described as
1268 (dimension, in staff space)
1270 Add this much extra space between objects that are next to each other.
1274 By increasing the value of @code{padding}, we can move the
1275 fingering away from the note head. The following command inserts
1276 3 staff spaces of white
1277 between the note and the fingering:
1279 \once \override Voice.Fingering #'padding = #3
1282 Inserting this command before the Fingering object is created,
1283 i.e., before @code{c2}, yields the following result:
1285 @lilypond[quote,relative=2,verbatim]
1286 \once \override Voice.Fingering #'padding = #3
1293 In this case, the context for this tweak is @code{Voice}. This
1294 fact can also be deduced from the program reference, for the page for
1295 the @rinternals{Fingering_engraver} plug-in says
1298 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1302 @node Naming conventions
1303 @subsection Naming conventions
1305 Another thing that is needed, is an overview of the various naming
1309 @item scheme functions: lowercase-with-hyphens (incl. one-word
1311 @item scheme functions: ly:plus-scheme-style
1312 @item music events, music classes and music properties:
1314 @item Grob interfaces: scheme-style
1315 @item backend properties: scheme-style (but X and Y!)
1316 @item contexts (and MusicExpressions and grobs): Capitalized or
1318 @item context properties: lowercaseFollowedByCamelCase
1320 Capitalized_followed_by_lowercase_and_with_underscores
1323 Questions to be answered:
1325 @item Which of these are conventions and which are rules?
1326 @item Which are rules of the underlying language, and which are
1330 @node Modifying properties
1331 @section Modifying properties
1333 @c TODO change the menu and subsection node names to use
1334 @c backslash once the new macro to handle the refs
1335 @c is available. Need to find and change all refs at
1336 @c the same time. -td
1339 * Overview of modifying properties::
1341 * The override command::
1342 * The tweak command::
1343 * set versus override::
1344 * Modifying alists::
1348 @node Overview of modifying properties
1349 @subsection Overview of modifying properties
1351 Each context is responsible for creating certain types of graphical
1352 objects. The settings used for printing these objects are also stored by
1353 context. By changing these settings, the appearance of objects can be
1356 There are two different kinds of properties stored in contexts:
1357 context properties and grob properties. Context properties are
1358 properties that apply to the context as a whole and control
1359 how the context itself is displayed. In contrast, grob properties
1360 apply to specific grob types that will be displayed in the context.
1362 The @code{\set} and @code{\unset} commands are used to change values
1363 for context properties. The @code{\override} and @code{\revert}
1364 commands are used to change values for grob properties.
1367 The syntax for this is
1370 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1373 Here @var{name} is the name of a graphical object, like
1374 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1375 variable of the formatting system (@q{grob property} or @q{layout
1376 property}). The latter is a symbol, so it must be quoted. The
1377 subsection @ref{Modifying properties}, explains what to fill in
1378 for @var{name}, @var{property}, and @var{value}. Here we only
1379 discuss the functionality of this command.
1384 \override Staff.Stem #'thickness = #4.0
1388 makes stems thicker (the default is 1.3, with staff line thickness as a
1389 unit). Since the command specifies @code{Staff} as context, it only
1390 applies to the current staff. Other staves will keep their normal
1391 appearance. Here we see the command in action:
1393 @lilypond[quote,verbatim,relative=2]
1395 \override Staff.Stem #'thickness = #4.0
1401 The @code{\override} command changes the definition of the @code{Stem}
1402 within the current @code{Staff}. After the command is interpreted
1403 all stems are thickened.
1405 Analogous to @code{\set}, the @var{context} argument may be left out,
1406 causing the default context @code{Voice} to be used. Adding
1407 @code{\once} applies the change during one timestep only.
1409 @lilypond[quote,verbatim,relative=2]
1411 \once \override Stem #'thickness = #4.0
1416 The @code{\override} must be done before the object is
1417 started. Therefore, when altering @emph{Spanner} objects such as slurs
1418 or beams, the @code{\override} command must be executed at the moment
1419 when the object is created. In this example,
1421 @lilypond[quote,verbatim,relative=2]
1422 \override Slur #'thickness = #3.0
1424 \override Beam #'beam-thickness = #0.6
1429 the slur is fatter but the beam is not. This is because the command for
1430 @code{Beam} comes after the Beam is started, so it has no effect.
1432 Analogous to @code{\unset}, the @code{\revert} command for a context
1433 undoes an @code{\override} command; like with @code{\unset}, it only
1434 affects settings that were made in the same context. In other words, the
1435 @code{\revert} in the next example does not do anything.
1438 \override Voice.Stem #'thickness = #4.0
1439 \revert Staff.Stem #'thickness
1442 Some tweakable options are called @q{subproperties} and reside inside
1443 properties. To tweak those, use commands of the form
1445 @c leave this as a long long
1447 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1454 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1461 @rinternals{Backend},
1462 @rinternals{All layout objects},
1463 @rinternals{OverrideProperty},
1464 @rinternals{RevertProperty},
1465 @rinternals{PropertySet}.
1470 The back-end is not very strict in type-checking object properties.
1471 Cyclic references in Scheme values for properties can cause hangs
1472 or crashes, or both.
1476 @node The set command
1477 @subsection The @code{@bs{}set} command
1481 @cindex changing properties
1483 Each context has a set of @emph{properties}, variables contained
1484 in that context. Context properties are changed with the @code{\set}
1485 command, which has the following syntax:
1488 \set @var{context}.@var{property} = #@var{value}
1491 @var{value} is a Scheme object, which is why it must be preceded by
1492 the @code{#}@tie{}character.
1494 Contexts properties are usually named in
1495 @code{studlyCaps}. They mostly control the translation from
1496 music to notation, e.g. @code{localKeySignature} (for determining
1497 whether to print accidentals), or @code{measurePosition} (for
1498 determining when to print a bar line). Context properties can
1499 change value over time while interpreting a piece of music;
1500 @code{measurePosition} is an obvious example of
1501 this. Context properties are modified with @code{\set}.
1503 For example, multimeasure rests will be combined into a single bar
1504 if the context property @code{skipBars} is set to @code{#t}:
1506 @lilypond[quote,verbatim,relative=2]
1508 \set Score.skipBars = ##t
1512 If the @var{context} argument is left out, then the property will be
1513 set in the current bottom context (typically @code{ChordNames},
1514 @code{Voice}, @code{TabVoice}, or @code{Lyrics}).
1516 @lilypond[quote,verbatim,relative=2]
1517 \set Score.autoBeaming = ##f
1521 \set autoBeaming = ##t
1529 The change is applied @q{on-the-fly}, during the music, so that the
1530 setting only affects the second group of eighth notes.
1532 Note that the bottom-most context does not always contain the property
1533 that you wish to change -- for example, attempting to set the
1534 @code{skipBars} property of the default bottom context, in this case
1535 @code{Voice}, will have no effect, because skipBars is a property of
1536 the @code{Score} context.
1538 @lilypond[quote,verbatim,relative=2]
1544 Contexts are hierarchical, so if an enclosing context was specified, for
1545 example @code{Staff}, then the change would also apply to all
1546 @code{Voice}s in the current staff.
1550 The @code{\unset} command:
1553 \unset @var{context}.@var{property}
1557 is used to remove the definition of @var{property} from
1558 @var{context}. This command removes
1559 the definition only if it is set in @var{context}.
1560 Properties that have been set in enclosing contexts will
1561 not be altered by an unset in an enclosed context:
1563 @lilypond[quote,verbatim,relative=2]
1564 \set Score.autoBeaming = ##t
1569 \unset Score.autoBeaming
1577 Like @code{\set}, the @var{context} argument does not have to be
1578 specified for a bottom context, so the two statements
1581 \set Voice.autoBeaming = ##t
1582 \set autoBeaming = ##t
1586 are equivalent if the current bottom context is @code{Voice}.
1590 Preceding a @code{\set} command by @code{\once} makes the
1591 setting apply to only a single time-step:
1593 @lilypond[quote,verbatim,relative=2]
1595 \once \set fontSize = #4.7
1600 A full description of all available context properties is in the
1601 internals reference, see
1603 @rinternals{Tunable context properties}.
1606 Translation @expansion{} Tunable context properties.
1611 Internals Reference:
1613 @rinternals{Tunable context properties}.
1616 @cindex grob properties
1617 @cindex properties, grob
1621 @node The override command
1622 @subsection The @code{\override} command
1624 There is a special type of context property: the grob
1625 description. Grob descriptions are named in @code{StudlyCaps}
1626 (starting with capital letters). They contain the
1627 @q{default settings} for a particular kind of grob as an
1628 association list. See @file{scm/define-grobs.scm}
1629 to see the settings for each grob description. Grob descriptions
1630 are modified with @code{\override}.
1632 @code{\override} is actually a shorthand;
1635 \override @var{context}.@var{GrobName} #'@var{property} = #@var{value}
1639 is more or less equivalent to
1641 @c leave this long line -gp
1643 \set @var{context}.@var{GrobName} =
1644 #(cons (cons '@var{property} @var{value})
1645 <previous value of @var{context}.@var{GrobName}>)
1648 The value of @code{context}.@code{GrobName} (the alist) is used to initialize
1649 the properties of individual grobs. Grobs have
1650 properties, named in Scheme style, with
1651 @code{dashed-words}. The values of grob properties change
1652 during the formatting process: formatting basically amounts
1653 to computing properties using callback functions.
1655 For example, we can increase the thickness of a note stem by
1656 overriding the @code{thickness} property of the @code{Stem}
1659 @lilypond[quote,verbatim,relative=2]
1661 \override Voice.Stem #'thickness = #3.0
1665 If no context is specified in an @code{\override}, the bottom
1668 @lilypond[quote,verbatim,relative=2]
1669 { \override Staff.Stem #'thickness = #3.0
1673 \override Stem #'thickness = #0.5
1683 @cindex reverting overrides
1684 @cindex overrides, reverting
1686 The effects of @code{\override} can be undone by @code{\revert}:
1688 @lilypond[quote,verbatim,relative=2]
1690 \override Voice.Stem #'thickness = #3.0
1692 \revert Voice.Stem #'thickness
1696 The effects of @code{\override} and @code{\revert} apply to all
1697 grobs in the affected context from the current time forward:
1699 @lilypond[quote,verbatim,relative=2]
1704 \override Staff.Stem #'thickness = #3.0
1708 \revert Staff.Stem #'thickness
1716 @cindex overriding for only one moment
1718 @code{\once} can be used with @code{\override}
1719 to affect only the current time step:
1721 @lilypond[quote,verbatim,relative=2]
1725 \override Stem #'thickness = #3.0
1729 \once \override Stem #'thickness = #3.0
1738 Commands which change output generally look like
1741 \override Voice.Stem #'thickness = #3.0
1745 To construct this tweak we must determine these bits of information:
1748 @item the context: here @code{Voice}.
1749 @item the layout object: here @code{Stem}.
1750 @item the layout property: here @code{thickness}.
1751 @item a sensible value: here @code{3.0}.
1754 Some tweakable options are called @q{subproperties} and reside inside
1755 properties. To tweak those, use commands in the form
1758 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1761 @cindex internal documentation
1762 @cindex finding graphical objects
1763 @cindex graphical object descriptions
1766 @cindex internal documentation
1768 For many properties, regardless of the data type of the property, setting the
1769 property to false (@code{#f}) will result in turning it off, causing
1770 LilyPond to ignore that property entirely. This is particularly useful for
1771 turning off grob properties which may otherwise be causing problems.
1773 We demonstrate how to glean this information from the notation manual
1774 and the program reference.
1779 Internals Reference:
1780 @rinternals{Backend}
1782 @node The tweak command
1783 @subsection The @code{\tweak} command
1788 Changing grob properties
1789 with @code{\override} causes the changes to apply to all of the
1790 given grobs in the context at the moment the change applies.
1791 Sometimes, however, it is desirable to have changes apply to just
1792 one grob, rather than to all grobs in the affected context. This is
1793 accomplished with the @code{\tweak} command, which has the following
1797 \tweak #'@code{grob-property} #@code{value}
1800 The @code{\tweak} command applies to the object that immediately
1801 follows @code{value} in the music stream.
1804 In some cases, it is possible to take a short-cut for tuning
1805 graphical objects. For objects that are created directly from
1806 an item in the input file, you can use the @code{\tweak} command.
1809 @lilypond[relative=2,verbatim,quote]
1814 \tweak #'duration-log #1
1817 -\tweak #'padding #8
1823 But the main use of the @code{\tweak} command is to modify just
1824 one of a number of notation elements which start at the same musical
1825 moment, like the notes of a chord, or tuplet brackets which start
1828 The @code{\tweak} command sets a property in the following object
1829 directly, without requiring the grob name or context to be
1830 specified. For this to work, it is necessary for the @code{\tweak}
1831 command to remain immediately adjacent to the object to which it is
1832 to apply after the input file has been converted to a music stream.
1833 This is often not the case, as many additional elements are inserted
1834 into the music stream implicitly. For example, when a note which is
1835 not part of a chord is processed, LilyPond implicitly inserts a
1836 @code{ChordEvent} event before the note, so separating the tweak
1837 from the note. However, if chord symbols are placed round the
1838 tweak and the note, the @code{\tweak} command comes after the
1839 @code{ChordEvent} in the music stream, so remaining adjacent to the
1840 note, and able to modify it.
1844 @lilypond[relative=2,verbatim,quote]
1845 <\tweak #'color #red c>4
1851 @lilypond[relative=2,verbatim,quote]
1852 \tweak #'color #red c4
1857 For an introduction to the syntax and uses of the tweak command
1858 see @rlearning{Tweaking methods}.
1860 When several similar items are placed at the same musical moment,
1861 the @code{\override} command cannot be used to modify just one of
1862 them -- this is where the @code{\tweak} command must be used.
1863 Items which may appear more than once at the same musical moment
1864 include the following:
1866 @c TODO expand to include any further uses of \tweak
1868 @item note heads of notes inside a chord
1869 @item articulation signs on a single note
1870 @item ties between notes in a chord
1871 @item tuplet brackets starting at the same time
1874 @c TODO add examples of these
1876 @cindex chord, modifying one note in
1878 In this example, the color of one note head and the type of another
1879 note head are modified within a single chord:
1881 @lilypond[relative=2,verbatim,quote]
1886 \tweak #'duration-log #1
1891 @code{\tweak} can be used to modify slurs:
1893 @lilypond[verbatim,quote,relative=1]
1894 c-\tweak #'thickness #5 ( d e f)
1898 For the @code{\tweak} command to work, it must
1899 remain immediately adjacent to the object to which it is
1900 to apply after the input file has been converted to a music stream.
1901 At times, LilyPond may insert additional items into the music stream
1902 during the parsing process. For example, when a note that is not
1903 explicitly part of a chord will be placed in a chord by LilyPond,
1904 so notes to be modified with @code{\tweak} must be placed inside
1907 @lilypond[relative=2,verbatim,quote]
1908 \tweak #'color #red c4
1909 <\tweak #'color #red c>4
1912 The @code{\tweak} command cannot be used to modify any item
1913 that does not appear explicitly in the input file. In particular
1914 it cannot be used to modify stems,
1915 beams or accidentals directly, since these are generated later by
1916 note heads, rather than by music elements in the input stream.
1917 Nor can @code{\tweak} be used to modify clefs or time
1918 signatures, since these become separated from any preceding
1919 @code{\tweak} command in the input stream by the automatic
1920 insertion of extra elements required to specify the context.
1922 Several @code{\tweak} commands may be placed before a
1923 notational element -- all affect it:
1925 @lilypond[verbatim,quote,relative=1]
1927 -\tweak #'style #'dashed-line
1928 -\tweak #'dash-fraction #0.2
1929 -\tweak #'thickness #3
1930 -\tweak #'color #red
1935 The music stream which is generated from a section of an input file,
1936 including any automatically inserted elements, may be examined,
1937 see @rextend{Displaying music expressions}. This may be helpful in
1938 determining what may be modified by a @code{\tweak} command, or
1939 in determining how to adjust the input to make a @code{\tweak}
1945 @rlearning{Tweaking methods}.
1948 @rextend{Displaying music expressions}.
1953 @cindex tweaks in a variable
1954 The @code{\tweak} command cannot be used inside a variable.
1956 @cindex tweaks in lyrics
1957 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1959 @cindex tweaking control points
1960 @cindex control points, tweaking
1962 The @code{\tweak} command will apply to only the first of several
1963 generated ties in a chord.
1965 @node set versus override
1966 @subsection @code{\set} vs. @code{\override}
1968 @c TODO -- This section is probably unnecessary now.
1971 We have seen two methods of changing properties: @code{\set} and
1972 @code{\override}. There are actually two different kinds of
1975 @code{fontSize} is a special property: it is equivalent to
1976 entering @code{\override ... #'font-size} for all pertinent
1977 objects. Since this is a common change, the special
1978 property (modified with @code{\set}) was created.
1983 @node Modifying alists
1984 @subsection Modifying alists
1986 Some user-configurable properties are internally represented as
1987 @emph{alists} (association lists), which store pairs of
1988 @emph{keys} and @emph{values}. The structure of an alist is:
1991 '((@var{key1} . @var{value1})
1992 (@var{key2} . @var{value2})
1993 (@var{key3} . @var{value3})
1997 If an alist is a grob property or @code{\paper} variable, its keys
1998 can be modified individually without affecting other keys.
2000 For example, to reduce the space between adjacent staves in a
2001 staff-group, use the @code{staff-staff-spacing} property of the
2002 @code{StaffGrouper} grob. The property is an alist with four
2003 keys: @code{basic-distance}, @code{minimum-distance},
2004 @code{padding}, and @code{stretchability}. The standard settings
2005 for this property are listed in the @qq{Backend} section of the
2006 Internals Reference (see @rinternals{StaffGrouper}):
2009 '((basic-distance . 9)
2010 (minimum-distance . 7)
2012 (stretchability . 5))
2015 One way to bring the staves closer together is by reducing the
2016 value of the @code{basic-distance} key (@code{9}) to match the
2017 value of @code{minimum-distance} (@code{7}). To modify a single
2018 key individually, use a @emph{nested declaration}:
2020 @lilypond[quote,verbatim]
2021 % default space between staves
2023 \new Staff { \clef treble c''1 }
2024 \new Staff { \clef bass c1 }
2027 % reduced space between staves
2028 \new PianoStaff \with {
2029 % this is the nested declaration
2030 \override StaffGrouper #'staff-staff-spacing #'basic-distance = #7
2032 \new Staff { \clef treble c''1 }
2033 \new Staff { \clef bass c1 }
2037 Using a nested declaration will update the specified key (such as
2038 @code{basic-distance} in the above example) without altering any
2039 other keys already set for the same property.
2041 Now suppose we want the staves to be as close as possible without
2042 overlapping. The simplest way to do this is to set all four alist
2043 keys to zero. However, it is not necessary to enter four nested
2044 declarations, one for each key. Instead, the property can be
2045 completely re-defined with one declaration, as an alist:
2047 @lilypond[quote,verbatim]
2048 \new PianoStaff \with {
2049 \override StaffGrouper #'staff-staff-spacing =
2050 #'((basic-distance . 0)
2051 (minimum-distance . 0)
2053 (stretchability . 0))
2055 \new Staff { \clef treble c''1 }
2056 \new Staff { \clef bass c1 }
2060 Note that any keys not explicitly listed in the alist definition
2061 will be reset to their @emph{default-when-unset} values. In the
2062 case of @code{staff-staff-spacing}, any unset key-values would be
2063 reset to zero (except @code{stretchability}, which takes the value
2064 of @code{basic-distance} when unset). Thus the following two
2065 declarations are equivalent:
2068 \override StaffGrouper #'staff-staff-spacing =
2069 #'((basic-distance . 7))
2071 \override StaffGrouper #'staff-staff-spacing =
2072 #'((basic-distance . 7)
2073 (minimum-distance . 0)
2075 (stretchability . 7))
2078 One (possibly unintended) consequence of this is the removal of
2079 any standard settings that are set in an initialization file and
2080 loaded each time an input file is compiled. In the above example,
2081 the standard settings for @code{padding} and
2082 @code{minimum-distance} (defined in @file{scm/define-grobs.scm})
2083 are reset to their default-when-unset values (zero for both keys).
2084 Defining a property or variable as an alist (of any size) will
2085 always reset all unset key-values to their default-when-unset
2086 values. Unless this is the intended result, it is safer to update
2087 key-values individually with a nested declaration.
2089 @warning{Nested declarations will not work for context property
2090 alists (such as @code{beamExceptions}, @code{keySignature},
2091 @code{timeSignatureSettings}, etc.). These properties can only be
2092 modified by completely re-defining them as alists.}
2095 @node Useful concepts and properties
2096 @section Useful concepts and properties
2101 * Direction and placement::
2102 * Context layout order::
2103 * Distances and measurements::
2104 * Staff symbol properties::
2106 * Visibility of objects::
2108 * Rotating objects::
2112 @subsection Input modes
2114 The way in which the notation contained within an input file is
2115 interpreted is determined by the current input mode.
2119 This is activated with the @code{\chordmode} command, and causes
2120 input to be interpreted with the syntax of chord notation, see
2121 @ref{Chord notation}. Chords are rendered as notes on a staff.
2123 Chord mode is also activated with the @code{\chords} command.
2124 This also creates a new @code{ChordNames} context and
2125 causes the following input to be interpreted with the syntax of
2126 chord notation and rendered as chord names in the @code{ChordNames}
2127 context, see @ref{Printing chord names}.
2131 This is activated with the @code{\drummode} command, and causes
2132 input to be interpreted with the syntax of drum notation, see
2133 @ref{Basic percussion notation}.
2135 Drum mode is also activated with the @code{\drums} command.
2136 This also creates a new @code{DrumStaff} context and causes the
2137 following input to be interpreted with the syntax of drum notation
2138 and rendered as drum symbols on a drum staff, see @ref{Basic
2139 percussion notation}.
2141 @strong{Figure mode}
2143 This is activated with the @code{\figuremode} command, and causes
2144 input to be interpreted with the syntax of figured bass, see
2145 @ref{Entering figured bass}.
2147 Figure mode is also activated with the @code{\figures} command.
2148 This also creates a new @code{FiguredBass} context and causes the
2149 following input to be interpreted with the figured bass syntax
2150 and rendered as figured bass symbols in the @code{FiguredBass}
2151 context, see @ref{Introduction to figured bass}.
2153 @strong{Fret and tab modes}
2155 There are no special input modes for entering fret and tab symbols.
2157 To create tab diagrams, enter notes or chords in note mode and
2158 render them in a @code{TabStaff} context, see
2159 @ref{Default tablatures}.
2161 To create fret diagrams above a staff, you have two choices.
2162 You can either use the @code{FretBoards} context (see
2163 @ref{Automatic fret diagrams} or you can enter them as a markup
2164 above the notes using the @code{\fret-diagram} command (see
2165 @ref{Fret diagram markups}).
2167 @strong{Lyrics mode}
2169 This is activated with the @code{\lyricmode} command, and causes
2170 input to be interpreted as lyric syllables with optional durations
2171 and associated lyric modifiers, see @ref{Vocal music}.
2173 Lyric mode is also activated with the @code{\addlyrics} command.
2174 This also creates a new @code{Lyrics} context and an implicit
2175 @code{\lyricsto} command which associates the following lyrics
2176 with the preceding music.
2178 @strong{Markup mode}
2180 This is activated with the @code{\markup} command, and causes
2181 input to be interpreted with the syntax of markup, see
2182 @ref{Text markup commands}.
2184 @c silly work-around for texinfo broken-ness
2185 @c (@strong{Note...} causes a spurious cross-reference in Info)
2188 This is the default mode or it may be activated with the
2189 @code{\notemode} command. Input is interpreted as pitches,
2190 durations, markup, etc and typeset as musical notation on a staff.
2192 It is not normally necessary to specify note mode explicitly, but
2193 it may be useful to do so in certain situations, for example if you
2194 are in lyric mode, chord mode or any other mode and want to insert
2195 something that only can be done with note mode syntax.
2197 For example, to indicate dynamic markings for the verses of a
2198 choral pieces it is necessary to enter note mode to interpret
2201 @lilypond[verbatim,relative=2,quote]
2204 \notemode{\set stanza = \markup{ \dynamic f 1. } }
2208 \notemode{\set stanza = \markup{ \dynamic p 2. } }
2215 @node Direction and placement
2216 @subsection Direction and placement
2218 In typesetting music the direction and placement of many items is
2219 a matter of choice. For example, the stems of notes can
2220 be directed up or down; lyrics, dynamics, and other expressive
2221 marks may be placed above or below the staff; text may be aligned
2222 left, right or center; etc. Most of these choices may be left to
2223 be determined automatically by LilyPond, but in some cases it may
2224 be desirable to force a particular direction or placement.
2226 @strong{Articulation direction indicators}
2228 By default some directions are always up or always down (e.g.
2229 dynamics or fermata), while other things can alternate between
2230 up or down based on the stem direction (like slurs or accents).
2232 @c TODO Add table showing these
2234 The default action may be overridden by prefixing the articulation
2235 by a @emph{direction indicator}. Three direction indicators are
2236 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
2237 and @code{-} (meaning @qq{use default direction}). The direction
2238 indicator can usually be omitted, in which case @code{-} is assumed,
2239 but a direction indicator is @strong{always} required before
2242 @item @code{\tweak} commands
2243 @item @code{\markup} commands
2244 @item @code{\tag} commands
2245 @item string markups, e.g. -"string"
2246 @item fingering instructions, e.g. @w{@code{-1}}
2247 @item articulation shortcuts, e.g. @w{@code{-.}}, @w{@code{->}}, @w{@code{--}}
2250 Direction indicators affect only the next note:
2252 @lilypond[verbatim,quote,relative=2]
2259 @strong{The direction property}
2261 The position or direction of many layout objects is controlled
2262 by the @code{direction} property.
2264 The value of the @code{direction} property may be
2265 set to @code{1}, meaning @qq{up} or @qq{above}, or to @w{@code{-1}},
2266 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
2267 @code{DOWN} may be used instead of @code{1} and @w{@code{-1}}
2268 respectively. The default direction may be specified by setting
2269 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
2270 in many cases predefined commands
2271 exist to specify the direction. These are all of the form
2274 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
2277 where @code{xxxNeutral} means @qq{use the default direction}.
2278 See @rlearning{Within-staff objects}.
2280 In a few cases, arpeggio being the only common example, the value
2281 of the @code{direction} property specifies whether the object
2282 is to be placed to the right or left of the parent object. In
2283 this case @w{@code{-1}} or @code{LEFT} means @qq{to the left} and
2284 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
2285 or @code{CENTER} means @qq{use the default} direction, as before.
2288 These all have side-axis set to #X
2289 AmbitusAccidental - direction has no effect
2291 StanzaNumber - not tried
2292 TrillPitchAccidental - not tried
2293 TrillPitchGroup - not tried
2296 These indications affect all notes until they are cancelled.
2298 @lilypond[verbatim,quote,relative=2]
2308 @node Context layout order
2309 @subsection Context layout order
2311 @cindex contexts, layout order
2313 Contexts are normally positioned in a system from top to bottom
2314 in the order in which they are encountered in the input file. When
2315 contexts are nested, the outer context will include inner nested
2316 contexts as specified in the input file, provided the inner contexts
2317 are included in the outer context's @qq{accepts} list. Nested
2318 contexts which are not included in the outer context's @qq{accepts}
2319 list will be repositioned below the outer context rather than nested
2322 Note that a context will be silently created implicitly if a command
2323 is encountered when there is no suitable context available to
2324 contain it. This can give rise to unexpected new staves or scores.
2326 The default order in which contexts are laid out and the
2327 @qq{accepts} list can be changed, see @ref{Aligning contexts}.
2331 @rprogram{An extra staff appears}.
2334 @node Distances and measurements
2335 @subsection Distances and measurements
2337 @cindex distances, absolute
2338 @cindex distances, scaled
2345 Distances in LilyPond are of two types: absolute and scaled.
2347 Absolute distances are used for specifying margins, indents, and
2348 other page layout details, and are by default specified in
2349 millimeters. Distances may be specified in other units by
2350 following the quantity by @code{\mm}, @code{\cm},
2351 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27 of
2352 an inch). Page layout distances can also be specified in scalable
2353 units (see the following paragraph) by appending
2354 @code{\staff-space} to the quantity. Page layout is described in
2355 detail in @ref{Page layout}.
2357 Scaled distances are always specified in units of the staff-space
2358 or, rarely, the half staff-space. The staff-space is the distance
2359 between two adjacent staff lines. The default value can be changed
2360 globally by setting the global staff size, or it can be overridden
2361 locally by changing the @code{staff-space} property of
2362 @code{StaffSymbol}. Scaled distances automatically scale with any
2363 change to the either the global staff size or the
2364 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2365 automatically only with changes to the global staff size.
2366 The global staff size thus enables the overall size of a rendered
2367 score to be easily varied. For the methods of setting the global
2368 staff size see @ref{Setting the staff size}.
2372 If just a section of a score needs to be rendered to a different
2373 scale, for example an ossia section or a footnote, the global staff
2374 size cannot simply be changed as this would affect the entire score.
2375 In such cases the change in size is made by overriding both the
2376 @code{staff-space} property of @code{StaffSymbol} and the size of
2377 the fonts. A Scheme function, @code{magstep}, is available to
2378 convert from a font size change to the equivalent change in
2379 @code{staff-space}. For an explanation and an example of its use,
2380 see @rlearning{Length and thickness of objects}.
2385 @rlearning{Length and thickness of objects}.
2389 @ref{Setting the staff size}.
2392 @node Staff symbol properties
2393 @subsection Staff symbol properties
2395 @cindex adjusting staff symbol
2396 @cindex drawing staff symbol
2397 @cindex staff symbol, setting of
2399 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2400 @c Need to think of uses for these properties. Eg 'line-positions
2401 @c is used in a snippet to thicken centre line.
2402 @c If retained, add @ref to here in 1.6.2 -td
2404 The vertical position of staff lines and the number of staff lines
2405 can be defined at the same time. As the following example shows,
2406 note positions are not influenced by the staff line positions.
2408 @warning{The @code{'line-positions} property overrides the
2409 @code{'line-count} property. The number of staff lines is
2410 implicitly defined by the number of elements in the list of values
2411 for @code{'line-positions}.}
2413 @lilypond[verbatim,quote,relative=1]
2415 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
2420 The width of a staff can be modified. The units are staff
2421 spaces. The spacing of objects inside the staff is not affected by
2424 @lilypond[verbatim,quote,relative=1]
2426 \override StaffSymbol #'width = #23
2433 @subsection Spanners
2435 Many objects of musical notation extend over several notes or even
2436 several bars. Examples are slurs, beams, tuplet brackets, volta
2437 repeat brackets, crescendi, trills, and glissandi. Such objects
2438 are collectively called @qq{spanners}, and have special properties to control
2439 their appearance and behaviour. Some of these properties are common
2440 to all spanners; others are restricted to a sub-set of the spanners.
2442 All spanners support the @code{spanner-interface}. A few, essentially
2443 those that draw a straight line between the two objects, support in
2444 addition the @code{line-spanner-interface}.
2446 @unnumberedsubsubsec Using the @code{spanner-interface}
2448 This interface provides two properties that apply to several spanners.
2450 @strong{@i{The @code{minimum-length} property}}
2452 The minimum length of the spanner is specified by the
2453 @code{minimum-length} property. Increasing this usually has the
2454 necessary effect of increasing the spacing of the notes between the
2455 two end points. However, this override has no effect on
2456 many spanners, as their length is determined by other considerations.
2457 A few examples where it is effective are shown below.
2467 Works as long as callback is made:
2471 Works not at all for:
2480 @lilypond[verbatim,quote,relative=2]
2483 % increase the length of the tie
2484 -\tweak #'minimum-length #5
2488 @lilypond[verbatim,quote,relative=2]
2490 \compressFullBarRests
2492 % increase the length of the rest bar
2493 \once \override MultiMeasureRest #'minimum-length = #20
2498 @lilypond[verbatim,quote,relative=2]
2500 % increase the length of the hairpin
2501 \override Hairpin #'minimum-length = #20
2505 This override can also be used to increase the length of slurs and
2508 @lilypond[verbatim,quote,relative=2]
2511 -\tweak #'minimum-length #5
2516 -\tweak #'minimum-length #5
2520 For some layout objects, the @code{minimum-length} property becomes
2521 effective only if the @code{set-spacing-rods} procedure is called
2522 explicitly. To do this, the @code{springs-and-rods} property should
2523 be set to @code{ly:spanner::set-spacing-rods}. For example,
2524 the minimum length of a glissando has no effect unless the
2525 @code{springs-and-rods} property is set:
2527 @lilypond[verbatim,quote,relative=1]
2531 % not effective alone
2532 \once \override Glissando #'minimum-length = #20
2535 % effective only when both overrides are present
2536 \once \override Glissando #'minimum-length = #20
2537 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2541 The same is true of the @code{Beam} object:
2543 @lilypond[verbatim,quote,relative=1]
2544 % not effective alone
2545 \once \override Beam #'minimum-length = #20
2548 % effective only when both overrides are present
2549 \once \override Beam #'minimum-length = #20
2550 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2554 @strong{@i{The @code{to-barline} property}}
2556 The second useful property of the @code{spanner-interface} is
2557 @code{to-barline}. By default this is true, causing hairpins and
2558 other spanners which are terminated on the first note of a measure to
2559 end instead on the immediately preceding bar line. If set to false,
2560 the spanner will extend beyond the bar line and end on the note
2563 @lilypond[verbatim,quote,relative=2]
2564 a \< a a a a \! a a a \break
2565 \override Hairpin #'to-barline = ##f
2566 a \< a a a a \! a a a
2569 This property is not effective for all spanners. For example,
2570 setting it to @code{#t} has no effect on slurs or phrasing slurs
2571 or on other spanners for which terminating on the bar line would
2574 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2576 Objects which support the @code{line-spanner-interface} include
2579 @item @code{DynamicTextSpanner}
2580 @item @code{Glissando}
2581 @item @code{TextSpanner}
2582 @item @code{TrillSpanner}
2583 @item @code{VoiceFollower}
2586 The routine responsible for drawing the stencils for these spanners is
2587 @code{ly:line-interface::print}. This routine determines the
2588 exact location of the two end points and draws a line
2589 between them, in the style requested. The locations of the two
2590 end points of the spanner are computed on-the-fly, but it is
2591 possible to override their Y-coordinates. The
2592 properties which need to be specified are nested
2593 two levels down within the property hierarchy, but the syntax of
2594 the @code{\override} command is quite simple:
2596 @lilypond[relative=2,quote,verbatim]
2598 \once \override Glissando #'(bound-details left Y) = #3
2599 \once \override Glissando #'(bound-details right Y) = #-2
2603 The units for the @code{Y} property are @code{staff-space}s,
2604 with the center line of the staff being the zero point.
2605 For the glissando, this is the value for @code{Y} at the
2606 X-coordinate corresponding to the center point of each note head,
2607 if the line is imagined to be extended to there.
2609 If @code{Y} is not set, the value is computed from the vertical
2610 position of the corresponding attachment point of the spanner.
2612 In case of a line break, the values for the end points are
2613 specified by the @code{left-broken} and @code{right-broken}
2614 sub-lists of @code{bound-details}. For example:
2616 @lilypond[relative=2,ragged-right,verbatim,quote]
2617 \override Glissando #'breakable = ##t
2618 \override Glissando #'(bound-details right-broken Y) = #-3
2619 c1 \glissando \break
2624 A number of further properties of the @code{left} and
2625 @code{right} sub-lists of the @code{bound-details} property
2626 may be modified in the same way as @code{Y}:
2630 This sets the Y-coordinate of the end point, in @code{staff-space}s
2631 offset from the staff center line. By default, it is the center of
2632 the bound object, so a glissando points to the vertical center of
2635 For horizontal spanners, such as text spanners and trill spanners,
2636 it is hardcoded to 0.
2639 This determines where the line starts and ends in the X-direction,
2640 relative to the bound object. So, a value of @w{@code{-1}} (or
2641 @code{LEFT}) makes the line start/end at the left side of the note
2642 head it is attached to.
2645 This is the absolute X-coordinate of the end point. It is usually
2646 computed on the fly, and overriding it has little useful effect.
2649 Line spanners may have symbols at the beginning or end, which is
2650 contained in this sub-property. This is for internal use; it is
2651 recommended that @code{text} be used instead.
2654 This is a markup that is evaluated to yield the stencil. It is used
2655 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2657 @lilypond[quote,ragged-right,relative=2,verbatim]
2658 \override TextSpanner #'(bound-details left text)
2659 = \markup { \small \bold Slower }
2660 c2\startTextSpan b c a\stopTextSpan
2663 @item stencil-align-dir-y
2664 @item stencil-offset
2665 Without setting one of these, the stencil is simply put at the
2666 end-point, centered on the line, as defined by the @code{X} and
2667 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2668 or @code{stencil-offset} will move the symbol at the edge vertically
2669 relative to the end point of the line:
2671 @lilypond[relative=1,quote,verbatim]
2672 \override TextSpanner
2673 #'(bound-details left stencil-align-dir-y) = #-2
2674 \override TextSpanner
2675 #'(bound-details right stencil-align-dir-y) = #UP
2677 \override TextSpanner
2678 #'(bound-details left text) = #"ggg"
2679 \override TextSpanner
2680 #'(bound-details right text) = #"hhh"
2681 c4^\startTextSpan c c c \stopTextSpan
2684 Note that negative values move the text @emph{up}, contrary to the
2685 effect that might be expected, as a value of @w{@code{-1}} or
2686 @code{DOWN} means align the @emph{bottom} edge of the text with
2687 the spanner line. A value of @code{1} or @code{UP} aligns
2688 the top edge of the text with the spanner line.
2691 Setting this sub-property to @code{#t} produces an arrowhead at the
2695 This sub-property controls the space between the specified
2696 end point of the line and the actual end. Without padding, a
2697 glissando would start and end in the center of each note head.
2701 The music function @code{\endSpanners} terminates the spanner
2702 which starts on the immediately following note prematurely. It
2703 is terminated after exactly one note, or at the following bar line
2704 if @code{to-barline} is true and a bar line occurs before the next
2707 @lilypond[verbatim,quote,ragged-right,relative=2]
2709 c2 \startTextSpan c2 c2
2714 When using @code{\endSpanners} it is not necessary to close
2715 \startTextSpan with \stopTextSpan, nor is it necessary to close
2716 hairpins with @code{\!}.
2720 Internals Reference:
2721 @rinternals{TextSpanner},
2722 @rinternals{Glissando},
2723 @rinternals{VoiceFollower},
2724 @rinternals{TrillSpanner},
2725 @rinternals{line-spanner-interface}.
2728 @node Visibility of objects
2729 @subsection Visibility of objects
2731 @cindex objects, visibility of
2732 @cindex grobs, visibility of
2733 @cindex visibility of objects
2735 There are four main ways in which the visibility of layout objects
2736 can be controlled: their stencil can be removed, they can be made
2737 transparent, they can be colored white, or their
2738 @code{break-visibility} property can be overridden. The first
2739 three apply to all layout objects; the last to just a few -- the
2740 @emph{breakable} objects. The Learning Manual introduces these
2741 four techniques, see @rlearning{Visibility and color of objects}.
2743 There are also a few other techniques which are specific to
2744 certain layout objects. These are covered under Special
2748 * Removing the stencil::
2749 * Making objects transparent::
2750 * Painting objects white::
2751 * Using break-visibility::
2752 * Special considerations::
2756 @node Removing the stencil
2757 @unnumberedsubsubsec Removing the stencil
2759 @cindex stencil, removing
2761 Every layout object has a stencil property. By default this is set
2762 to the specific function which draws that object. If this property
2763 is overridden to @code{#f} no function will be called and the object
2764 will not be drawn. The default action can be recovered with
2767 @lilypond[quote,verbatim,relative=1]
2769 \override Score.BarLine #'stencil = ##f
2771 \revert Score.BarLine #'stencil
2775 @node Making objects transparent
2776 @unnumberedsubsubsec Making objects transparent
2778 @cindex transparent, making objects
2780 Every layout object has a transparent property which by default is
2781 set to @code{#f}. If set to @code{#t} the object still occupies
2782 space but is made invisible.
2784 @lilypond[quote,verbatim,relative=2]
2786 \once \override NoteHead #'transparent = ##t
2790 @node Painting objects white
2791 @unnumberedsubsubsec Painting objects white
2793 @cindex objects, coloring
2794 @cindex coloring objects
2796 @cindex printing order
2797 @cindex overwriting objects
2798 @cindex objects, overwriting
2799 @cindex grobs, overwriting
2801 Every layout object has a color property which by default is set
2802 to @code{black}. If this is overridden to @code{white} the object
2803 will be indistinguishable from the white background. However,
2804 if the object crosses other objects the color of the crossing
2805 points will be determined by the order in which they are drawn,
2806 and this may leave a ghostly image of the white object, as shown
2809 @lilypond[quote,verbatim,relative=2]
2810 \override Staff.Clef #'color = #white
2814 This may be avoided by changing the order of printing the objects.
2815 All layout objects have a @code{layer} property which should be set
2816 to an integer. Objects with the lowest value of @code{layer} are
2817 drawn first, then objects with progressively higher values are drawn,
2818 so objects with higher values overwrite objects with lower values.
2819 By default most objects are assigned a @code{layer} value of
2820 @code{1}, although a few objects, including @code{StaffSymbol} and
2821 @code{BarLine}, are assigned a value of @code{0}. The order of
2822 printing objects with the same value of @code{layer} is indeterminate.
2824 In the example above the white clef, with a default @code{layer}
2825 value of @code{1}, is drawn after the staff lines (default
2826 @code{layer} value @code{0}), so overwriting them. To change this,
2827 the @code{Clef} object must be given in a lower value of
2828 @code{layer}, say @w{@code{-1}}, so that it is drawn earlier:
2830 @lilypond[quote,verbatim,relative=2]
2831 \override Staff.Clef #'color = #white
2832 \override Staff.Clef #'layer = #-1
2836 @node Using break-visibility
2837 @unnumberedsubsubsec Using break-visibility
2839 @c TODO Add making other objects breakable
2841 @cindex break-visibility
2843 Most layout objects are printed only once, but some like
2844 bar lines, clefs, time signatures and key signatures, may need
2845 to be printed twice when a line break occurs -- once at the end
2846 of the line and again at the start of the next line. Such
2847 objects are called @emph{breakable}, and have a property, the
2848 @code{break-visibility} property to control their visibility
2849 at the three positions in which they may appear -- at the
2850 start of a line, within a line if they are changed, and at the
2851 end of a line if a change takes place there.
2853 For example, the time signature
2854 by default will be printed at the start of the first line, but
2855 nowhere else unless it changes, when it will be printed at the
2856 point at which the change occurs. If this change occurs at the
2857 end of a line the new time signature will be printed at the start
2858 of the next line and a cautionary time signature will be printed
2859 at the end of the previous line as well.
2861 This behaviour is controlled by the @code{break-visibility}
2862 property, which is explained in
2863 @c Leave this ref on a newline - formats incorrectly otherwise -td
2864 @rlearning{Visibility and color of objects}. This property takes
2865 a vector of three booleans which, in order, determine whether the
2866 object is printed at the end of, within the body of, or at the
2867 beginning of a line. Or to be more precise, before a line break,
2868 where there is no line break, or after a line break.
2870 Alternatively, these eight combinations may be specified
2871 by pre-defined functions, defined in @file{scm/output-lib.scm},
2872 where the last three columns indicate whether the layout objects
2873 will be visible in the positions shown at the head of the columns:
2875 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2876 @headitem Function @tab Vector @tab Before @tab At no @tab After
2877 @headitem form @tab form @tab break @tab break @tab break
2879 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2880 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2881 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2882 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2883 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2884 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2885 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2886 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2889 The default settings of @code{break-visibility} depend on the
2890 layout object. The following table shows all the layout objects
2891 of interest which are affected by @code{break-visibility} and the
2892 default setting of this property:
2894 @multitable @columnfractions .3 .3 .4
2896 @headitem Layout object @tab Usual context @tab Default setting
2898 @c omit Ambitus as it appears not to be affected by break-visibility -td
2899 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2900 @item @code{BarLine} @tab @code{Score} @tab calculated
2901 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2902 @c omit the following item until it can be explained -td
2903 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2904 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2905 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2906 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2907 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2908 @c omit KeyCancellation until it can be explained -td
2909 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2910 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2911 @c omit LeftEdge until it can be explained -td
2912 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2913 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2914 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2915 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2919 The example below shows the use of the vector form to control the
2920 visibility of bar lines:
2922 @lilypond[quote,verbatim,relative=1,ragged-right]
2925 % Remove bar line at the end of the current line
2926 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2932 Although all three components of the vector used to override
2933 @code{break-visibility} must be present, not all of them are
2934 effective with every layout object, and some combinations may
2935 even give errors. The following limitations apply:
2938 @item Bar lines cannot be printed at start of line.
2939 @item A bar number cannot be printed at the start of the first
2940 line unless it is set to be different from 1.
2941 @item Clef -- see below
2942 @item Double percent repeats are either all printed or all
2943 suppressed. Use begin-of line-invisible to print and
2944 all-invisible to suppress.
2945 @item Key signature -- see below
2946 @item OctavateEight -- see below
2949 @node Special considerations
2950 @unnumberedsubsubsec Special considerations
2952 @strong{@emph{Visibility following explicit changes}}
2954 @cindex key signature, visibility following explicit change
2955 @cindex explicitKeySignatureVisibility
2956 @cindex clef, visibility following explicit change
2957 @cindex explicitClefVisibility
2959 The @code{break-visibility} property controls the visibility of
2960 key signatures and changes of clef only at the start of lines,
2961 i.e. after a break. It has no effect on the visibility of the
2962 key signature or clef following an explicit key change or an
2963 explicit clef change within or at the end of a line. In the
2964 following example the key signature following the explicit change
2965 to B-flat major is still visible, even though @code{all-invisible}
2968 @lilypond[quote,verbatim,relative=1,ragged-right]
2971 % Try to remove all key signatures
2972 \override Staff.KeySignature #'break-visibility = #all-invisible
2980 The visibility of such explicit key signature and clef changes is
2981 controlled by the @code{explicitKeySignatureVisibility} and
2982 @code{explicitClefVisibility} properties. These are the equivalent
2983 of the @code{break-visibility} property and both take a vector of
2984 three booleans or the predefined functions listed above, exactly like
2985 @code{break-visibility}. Both are properties of the Staff context,
2986 not the layout objects themselves, and so they are set using the
2987 @code{\set} command. Both are set by default to @code{all-visible}.
2988 These properties control only the visibility of key signatures and
2989 clefs resulting from explicit changes and do not affect key
2990 signatures and clefs at the beginning of lines;
2991 @code{break-visibility} must still be overridden in the appropriate
2992 object to remove these.
2994 @lilypond[quote,verbatim,relative=1,ragged-right]
2997 \set Staff.explicitKeySignatureVisibility = #all-invisible
2998 \override Staff.KeySignature #'break-visibility = #all-invisible
3005 @strong{@emph{Visibility of cautionary accidentals}}
3007 To remove the cautionary accidentals printed at an explicit key
3008 change, set the Staff context property @code{printKeyCancellation}
3011 @lilypond[quote,verbatim,relative=1,ragged-right]
3014 \set Staff.explicitKeySignatureVisibility = #all-invisible
3015 \set Staff.printKeyCancellation = ##f
3016 \override Staff.KeySignature #'break-visibility = #all-invisible
3023 With these overrides only the accidentals before the notes remain
3024 to indicate the change of key.
3026 @c TODO Add visibility of cautionary accidentals before notes
3028 @strong{@emph{Automatic bars}}
3030 @cindex automaticBars
3031 @cindex bar lines, suppressing
3033 As a special case, the printing of bar lines can also be turned off
3034 by setting the @code{automaticBars} property in the Score context.
3035 If set to @code{#f}, bar lines will not be printed automatically;
3036 they must be explicitly created with a @code{\bar} command. Unlike
3037 the @code{\cadenzaOn} predefined command, measures are still counted.
3038 Bar generation will resume according to that count if this property
3039 is later set to @code{#t}. When set to @code{#f}, line breaks can
3040 occur only at explicit @code{\bar} commands.
3044 @strong{@emph{Octavated clefs}}
3046 @cindex octavated clefs, visibility of
3047 @cindex visibility of octavated clefs
3048 @cindex clefs, visibility of octavation
3050 The small octavation symbol on octavated clefs is produced by the
3051 @code{OctavateEight} layout object. Its visibility is automatically
3052 inherited from the @code{Clef} object, so it is not necessary to apply
3053 any required @code{break-visibility} overrides to the @code{OctavateEight}
3054 layout objects to suppress octavation symbols for invisible clefs.
3056 For explicit clef changes, the @code{explicitClefVisibility}
3057 property controls both the clef symbol and any octavation symbol
3063 @rlearning{Visibility and color of objects}
3067 @subsection Line styles
3069 Some performance indications, e.g., @i{rallentando} and
3070 @i{accelerando} and @i{trills} are written as text and are
3071 extended over many measures with lines, sometimes dotted or wavy.
3073 These all use the same routines as the glissando for drawing the
3074 texts and the lines, and tuning their behavior is therefore also
3075 done in the same way. It is done with a spanner, and the routine
3076 responsible for drawing the spanners is
3077 @code{ly:line-interface::print}. This routine determines the
3078 exact location of the two @i{span points} and draws a line
3079 between them, in the style requested.
3081 Here is an example showing the different line styles available,
3082 and how to tune them.
3084 @lilypond[relative=2,ragged-right,verbatim,quote]
3086 \once \override Glissando #'style = #'dashed-line
3088 \override Glissando #'style = #'dotted-line
3090 \override Glissando #'style = #'zigzag
3092 \override Glissando #'style = #'trill
3096 The locations of the end-points of the spanner are computed
3097 on-the-fly for every graphic object, but it is possible to
3101 @lilypond[relative=2,ragged-right,verbatim,quote]
3103 \once \override Glissando #'(bound-details right Y) = #-2
3107 The value for @code{Y} is set to @w{@code{-2}} for the right end
3108 point. The left side may be similarly adjusted by specifying
3109 @code{left} instead of @code{right}.
3111 If @code{Y} is not set, the value is computed from the vertical
3112 position of the left and right attachment points of the spanner.
3114 Other adjustments of spanners are possible, for details, see
3117 @node Rotating objects
3118 @subsection Rotating objects
3120 Both layout objects and elements of markup text can be rotated by
3121 any angle about any point, but the method of doing so differs.
3124 * Rotating layout objects::
3128 @node Rotating layout objects
3129 @unnumberedsubsubsec Rotating layout objects
3131 @cindex rotating objects
3132 @cindex objects, rotating
3134 All layout objects which support the @code{grob-interface} can be
3135 rotated by setting their @code{rotation} property. This takes a
3136 list of three items: the angle of rotation counter-clockwise,
3137 and the x and y coordinates of the point relative to the object's
3138 reference point about which the rotation is to be performed. The
3139 angle of rotation is specified in degrees and the coordinates in
3142 The angle of rotation and the coordinates of the rotation point must
3143 be determined by trial and error.
3145 @cindex hairpins, angled
3146 @cindex angled hairpins
3148 There are only a few situations where the rotation of layout
3149 objects is useful; the following example shows one situation where
3152 @lilypond[quote,verbatim,relative=1]
3154 \override Hairpin #'rotation = #'(20 -1 0)
3158 @node Rotating markup
3159 @unnumberedsubsubsec Rotating markup
3161 All markup text can be rotated to lie at any angle by prefixing it
3162 with the @code{\rotate} command. The command takes two arguments:
3163 the angle of rotation in degrees counter-clockwise and the text to
3164 be rotated. The extents of the text are not rotated: they take
3165 their values from the extremes of the x and y coordinates of the
3166 rotated text. In the following example the
3167 @code{outside-staff-priority} property for text is set to @code{#f}
3168 to disable the automatic collision avoidance, which would push some
3169 of the text too high.
3171 @lilypond[quote,verbatim,relative=1]
3172 \override TextScript #'outside-staff-priority = ##f
3173 g4^\markup { \rotate #30 "a G" }
3174 b^\markup { \rotate #30 "a B" }
3175 des^\markup { \rotate #30 "a D-Flat" }
3176 fis^\markup { \rotate #30 "an F-Sharp" }
3179 @node Advanced tweaks
3180 @section Advanced tweaks
3182 This section discusses various approaches to fine tuning the
3183 appearance of the printed score.
3186 * Aligning objects::
3187 * Vertical grouping of grobs::
3188 * Modifying stencils::
3189 * Modifying shapes::
3195 @rlearning{Tweaking output},
3196 @rlearning{Other sources of information}.
3199 @ref{Explaining the Internals Reference},
3200 @ref{Modifying properties}.
3203 @file{scm/define-grobs.scm}.
3206 @rlsr{Tweaks and overrides}.
3209 @rextend{Interfaces for programmers}.
3211 Internals Reference:
3212 @rinternals{All layout objects}.
3215 @node Aligning objects
3216 @subsection Aligning objects
3218 Graphical objects which support the @code{self-alignment-interface}
3219 and/or the @code{side-position-interface} can be aligned to a previously
3220 placed object in a variety of ways. For a list of these objects, see
3221 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
3223 All graphical objects have a reference point, a horizontal extent and a
3224 vertical extent. The horizontal extent is a pair of numbers
3225 giving the displacements from the reference point of the left and
3226 right edges, displacements to the left being negative. The vertical
3227 extent is a pair of numbers giving the displacement from the reference
3228 point to the bottom and top edges, displacements down being negative.
3230 An object's position on a staff is given by the values of the
3231 @code{X-offset} and @code{Y-offset} properties. The value of
3232 @code{X-offset} gives the displacement from the X coordinate of
3233 the reference point of the parent object, and the value of
3234 @code{Y-offset} gives the displacement from the center line of the
3235 staff. The values of @code{X-offset} and @code{Y-offset} may
3236 be set directly or may be set to be calculated by procedures in order
3237 to achieve alignment with the parent object.
3239 @warning{Many objects have special positioning considerations which
3240 cause any setting of @code{X-offset} or @code{Y-offset} to be
3241 ignored or modified, even though the object supports the
3242 @code{self-alignment-interface}. Overriding the @code{X-offset}
3243 or @code{Y-offset} properties to a fixed value causes the respective
3244 @code{self-alignment} property to be disregarded.}
3246 For example, an accidental can be repositioned vertically by setting
3247 @code{Y-offset} but any changes to @code{X-offset} have no effect.
3249 Rehearsal marks may be aligned with breakable objects such as bar
3250 lines, clef symbols, time signature symbols and key signatures. There
3251 are special properties to be found in the @code{break-aligned-interface}
3252 for positioning rehearsal marks on such objects.
3255 @ref{Using the break-alignable-interface},
3256 @rextend{Callback functions}.
3259 * Setting X-offset and Y-offset directly::
3260 * Using the side-position-interface::
3261 * Using the self-alignment-interface::
3262 * Using the break-alignable-interface::
3265 @node Setting X-offset and Y-offset directly
3266 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
3268 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
3269 properties of many objects. The following example shows three
3270 notes with the default fingering position and the positions with @code{X-offset}
3271 and @code{Y-offset} modified.
3273 @lilypond[verbatim,quote,relative=2]
3276 -\tweak #'X-offset #0
3277 -\tweak #'Y-offset #0
3280 -\tweak #'X-offset #-1
3281 -\tweak #'Y-offset #1
3287 @node Using the side-position-interface
3288 @unnumberedsubsubsec Using the @code{side-position-interface}
3290 An object which supports the @code{side-position-interface} can be
3291 placed next to its parent object so that
3292 the specified edges of the two objects touch. The object may be
3293 placed above, below, to the right or to the left of the parent.
3294 The parent cannot be specified; it is determined by the order of
3295 elements in the input stream. Most objects have the associated
3296 note head as their parent.
3298 The values of the @code{side-axis} and @code{direction} properties
3299 determine where the object is to be placed, as follows:
3301 @c TODO add an example of each to the table
3303 @multitable @columnfractions .3 .3 .3
3304 @headitem @code{side-axis} @tab @code{direction} @tab
3305 @headitem property @tab property @tab Placement
3307 @item @code{0} @tab @code{-1} @tab left
3308 @item @code{0} @tab @code{1} @tab right
3309 @item @code{1} @tab @code{-1} @tab below
3310 @item @code{1} @tab @code{1} @tab above
3314 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
3315 the procedure @code{ly:side-position-interface::x-aligned-side}.
3316 This procedure will return the correct value of @code{X-offset} to
3317 place the object to the left or right side of the parent according
3318 to value of @code{direction}.
3320 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3321 the procedure @code{ly:side-position-interface::y-aligned-side}.
3322 This procedure will return the correct value of @code{Y-offset} to
3323 place the object to the top or bottom of the parent according
3324 to value of @code{direction}.
3326 @c TODO Add examples
3328 @node Using the self-alignment-interface
3329 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3331 @emph{Self-aligning objects horizontally}
3333 The horizontal alignment of an object which supports the
3334 @code{self-alignment-interface} is controlled by the value of
3335 the @code{self-alignment-X} property, provided the object's
3336 @code{X-offset} property is set to
3337 @code{ly:self-alignment-interface::x-aligned-on-self}.
3338 @code{self-alignment-X} may be given any
3339 real value, in units of half the total X extent of the
3340 object. Negative values move the object to the right, positive
3341 to the left. A value of @code{0} centers the object on the
3342 reference point of its parent, a value of @w{@code{-1}} aligns the
3343 left edge of the object on the reference point of its parent,
3344 and a value of @code{1} aligns the right edge of the object on the
3345 reference point of its parent. The symbols @code{LEFT},
3346 @code{CENTER}, and @code{RIGHT} may be used instead of the values
3347 @w{@code{-1}}, @code{0}, and @code{1}, respectively.
3349 Normally the @code{\override} command would be used to modify the
3350 value of @code{self-alignment-X}, but the @code{\tweak} command
3351 can be used to separately align several annotations on a single
3354 @lilypond[quote,verbatim,relative=1]
3356 -\tweak #'self-alignment-X #-1
3358 -\tweak #'self-alignment-X #0
3360 -\tweak #'self-alignment-X #RIGHT
3362 -\tweak #'self-alignment-X #-2.5
3363 ^"aligned further to the right"
3366 @emph{Self-aligning objects vertically}
3368 Objects may be aligned vertically in an analogous way to aligning
3369 them horizontally if the @code{Y-offset} property is set to
3370 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3371 other mechanisms are often involved in vertical alignment: the
3372 value of @code{Y-offset} is just one variable taken into account.
3373 This may make adjusting the value of some objects tricky.
3374 The units are just half the vertical extent of the object, which
3375 is usually quite small, so quite large numbers may be required.
3376 A value of @w{@code{-1}} aligns the lower edge of the object with
3377 the reference point of the parent object, a value of @code{0}
3378 aligns the center of the object with the reference point of the
3379 parent, and a value of @code{1} aligns the top edge of the object
3380 with the reference point of the parent. The symbols @code{DOWN},
3381 @code{CENTER}, and @code{UP} may be substituted for @w{@code{-1}},
3382 @code{0}, and @code{1}, respectively.
3384 @emph{Self-aligning objects in both directions}
3386 By setting both @code{X-offset} and @code{Y-offset}, an object may
3387 be aligned in both directions simultaneously.
3389 The following example shows how to adjust a fingering mark so
3390 that it nestles close to the note head.
3392 @lilypond[quote,verbatim,relative=2]
3394 -\tweak #'self-alignment-X #0.5 % move horizontally left
3395 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
3396 -\tweak #'self-alignment-Y #-1 % move vertically up
3401 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3403 @c Cannot document as they do not seem to operate consistently on all objects -td
3404 @c TODO investigate further
3406 The @code{aligned-on-parent} procedures are used in the same way
3407 as the @code{aligned-on-self} procedures, they difference being
3408 that they permit an object to be aligned with the @emph{edges} of
3409 the parent rather than the parent's reference point. The following
3410 example shows the difference:
3414 @lilypond[verbatim,quote]
3420 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3422 @c Cannot document as they do not seem to operate consistently on all objects -td
3423 @c TODO investigate further
3427 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3429 @node Using the break-alignable-interface
3430 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3432 @cindex align to objects
3433 @cindex break-align-symbols
3435 Rehearsal marks and bar numbers may be aligned with notation
3436 objects other than bar lines. These objects include @code{ambitus},
3437 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3438 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3439 @code{time-signature}.
3441 By default, rehearsal marks and bar numbers will be horizontally
3442 centered above the object:
3444 @lilypond[verbatim,quote,relative=1]
3445 % The rehearsal mark will be centered above the Clef
3446 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
3451 % The rehearsal mark will be centered above the Time Signature
3452 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
3458 % The rehearsal mark will be centered above the Breath Mark
3459 \override Score.RehearsalMark #'break-align-symbols = #'(breathing-sign)
3468 A list of possible target alignment objects may be specified. If
3469 some of the objects are invisible at that point due to the setting
3470 of @code{break-visibility} or the explicit visibility settings for
3471 keys and clefs, the rehearsal mark or bar number is aligned to the
3472 first object in the list which is visible. If no objects in the
3473 list are visible the object is aligned to the bar line. If the bar
3474 line is invisible the object is aligned to the place where the bar
3477 @lilypond[verbatim,quote,relative=1]
3478 % The rehearsal mark will be centered above the Key Signature
3479 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3484 % The rehearsal mark will be centered above the Clef
3485 \set Staff.explicitKeySignatureVisibility = #all-invisible
3486 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3491 % The rehearsal mark will be centered above the Bar Line
3492 \set Staff.explicitKeySignatureVisibility = #all-invisible
3493 \set Staff.explicitClefVisibility = #all-invisible
3494 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3501 The alignment of the rehearsal mark relative to the notation object
3502 can be changed, as shown in the following example. In a score with
3503 multiple staves, this setting should be done for all the staves.
3505 @lilypond[verbatim,quote,relative=1]
3506 % The RehearsalMark will be centered above the Key Signature
3507 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3513 % The RehearsalMark will be aligned with the left edge of the Key Signature
3514 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3518 % The RehearsalMark will be aligned with the right edge of the Key Signature
3519 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3525 The rehearsal mark can also be offset to the right or left of the left
3526 edge by an arbitrary amount. The units are staff-spaces:
3528 @lilypond[verbatim,quote,relative=1]
3529 % The RehearsalMark will be aligned with the left edge of the Key Signature
3530 % and then shifted right by 3.5 staff-spaces
3531 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3532 \once \override Score.KeySignature #'break-align-anchor = #3.5
3536 % The RehearsalMark will be aligned with the left edge of the Key Signature
3537 % and then shifted left by 2 staff-spaces
3538 \once \override Score.KeySignature #'break-align-anchor = #-2
3545 @node Vertical grouping of grobs
3546 @subsection Vertical grouping of grobs
3548 @c TODO Expand this section
3550 The VerticalAlignment and VerticalAxisGroup grobs work together.
3551 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3552 etc. VerticalAlignment then vertically aligns the different grobs
3553 grouped together by VerticalAxisGroup. There is usually only one
3554 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3558 @node Modifying stencils
3559 @subsection Modifying stencils
3561 All layout objects have a @code{stencil} property which is part of
3562 the @code{grob-interface}. By default, this property is usually
3563 set to a function specific to the object that is tailor-made to
3564 render the symbol which represents it in the output. For example,
3565 the standard setting for the @code{stencil} property of the
3566 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3568 The standard symbol for any object can be replaced by modifying the
3569 @code{stencil} property to reference a different, specially-written,
3570 procedure. This requires a high level of knowledge of the internal
3571 workings of LilyPond, but there is an easier way which can often
3572 produce adequate results.
3574 This is to set the @code{stencil} property to the procedure which
3575 prints text -- @code{ly:text-interface::print} -- and to add a
3576 @code{text} property to the object which is set to contain the
3577 markup text which produces the required symbol. Due to the
3578 flexibility of markup, much can be achieved -- see in particular
3579 @ref{Graphic notation inside markup}.
3581 The following example demonstrates this by changing the note head
3582 symbol to a cross within a circle.
3584 @lilypond[verbatim,quote]
3586 \once \override NoteHead #'stencil = #ly:text-interface::print
3587 \once \override NoteHead #'text = \markup {
3589 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3590 \musicglyph #"noteheads.s2cross"
3598 Any of the glyphs in the feta Font can be supplied to the
3599 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3601 @c TODO Add inserting eps files or ref to later
3603 @c TODO Add inserting Postscript or ref to later
3608 @ref{Graphic notation inside markup},
3609 @ref{Formatting text},
3610 @ref{Text markup commands},
3611 @ref{The Feta font}.
3614 @node Modifying shapes
3615 @subsection Modifying shapes
3618 * Modifying ties and slurs::
3621 @node Modifying ties and slurs
3622 @unnumberedsubsubsec Modifying ties and slurs
3624 @cindex slurs, modifying
3625 @cindex ties, modifying
3626 @cindex Bézier curves, control points
3627 @cindex control points, Bézier curves
3629 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3630 curves. If the shape of the tie or slur which is calculated
3631 automatically is not optimum, the shape may be modified manually by
3632 explicitly specifying the four control points required to define
3633 a third-order Bézier curve.
3635 Third-order or cubic Bézier curves are defined by four control
3636 points. The first and fourth control points are precisely the
3637 starting and ending points of the curve. The intermediate two
3638 control points define the shape. Animations showing how the curve
3639 is drawn can be found on the web, but the following description
3640 may be helpful. The curve starts from the first control point
3641 heading directly towards the second, gradually bending over to
3642 head towards the third and continuing to bend over to head towards
3643 the fourth, arriving there travelling directly from the third
3644 control point. The curve is entirely contained in the
3645 quadrilateral defined by the four control points.
3647 Here is an example of a case where the tie is not optimum, and
3648 where @code{\tieDown} would not help.
3650 @lilypond[verbatim,quote,relative=1]
3654 { r4 <g c,> <g c,> <g c,> }
3658 One way of improving this tie is to manually modify its control
3661 The coordinates of the Bézier control points are specified in units
3662 of staff-spaces. The X@tie{}coordinate is relative to the reference
3663 point of the note to which the tie or slur is attached, and the
3664 Y@tie{}coordinate is relative to the staff center line. The
3665 coordinates are entered as a list of four pairs of decimal numbers
3666 (reals). One approach is to estimate the coordinates of the two
3667 end points, and then guess the two intermediate points. The optimum
3668 values are then found by trial and error.
3670 It is useful to remember that a symmetric curve requires symmetric
3671 control points, and that Bézier curves have the useful property that
3672 transformations of the curve such as translation, rotation and
3673 scaling can be achieved by applying the same transformation to the
3674 curve's control points.
3676 For the example above the following override gives a satisfactory
3677 tie. Note the placement -- it has to be immediately before the note
3678 to which the start of the tie (or slur) is attached.
3680 @lilypond[verbatim,quote,relative=1]
3684 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3688 { r4 <g c,> <g c,> <g c,> }
3693 It is not possible to modify shapes of ties or slurs by changing
3694 the @code{control-points} property if there are multiple ties or slurs
3695 at the same musical moment -- the @code{\tweak} command will also not
3696 work in this case. However, the @code{tie-configuration} property of
3697 @code{TieColumn} can be overridden to set start line and direction as
3701 Internals Reference:
3702 @rinternals{TieColumn}.
3705 @node Using music functions
3706 @section Using music functions
3708 @c TODO -- add @seealso, etc. to these subsections
3710 Where tweaks need to be reused with different music expressions,
3711 it is often convenient to make the tweak part of a @emph{music
3712 function}. In this section, we discuss only @emph{substitution}
3713 functions, where the object is to substitute a variable into a
3714 piece of LilyPond input code. Other more complex functions are
3715 described in @rextend{Music functions}.
3718 * Substitution function syntax::
3719 * Substitution function examples::
3722 @node Substitution function syntax
3723 @subsection Substitution function syntax
3725 Making a function that substitutes a variable into LilyPond
3726 code is easy. The general form of these functions is
3730 #(define-music-function
3731 (parser location @var{arg1} @var{arg2} @dots{})
3732 (@var{type1?} @var{type2?} @dots{})
3734 @var{@dots{}music@dots{}}
3741 @multitable @columnfractions .33 .66
3742 @item @code{@var{argN}}
3743 @tab @var{n}th argument
3745 @item @code{@var{typeN?}}
3746 @tab a scheme @emph{type predicate} for which @code{@var{argN}}
3747 must return @code{#t}.
3749 @item @code{@var{@dots{}music@dots{}}}
3750 @tab normal LilyPond input, using @code{$} to reference arguments
3755 The @code{parser} and @code{location} arguments are mandatory, and
3756 are used in some advanced situations as described in the
3757 @q{Extending} manual (see @rextend{Music functions}). For
3758 substitution functions, just be sure to include them.
3760 The list of type predicates is also required. Some of the most
3761 common type predicates used in music functions are:
3765 cheap-list? @emph{(use instead of }@q{list?}@emph{ for faster processing)}
3775 For a list of available type predicates, see
3776 @ref{Predefined type predicates}. User-defined type predicates
3783 @ref{Predefined type predicates}.
3786 @rextend{Music functions}.
3789 @file{lily/music-scheme.cc},
3791 @file{scm/lily.scm}.
3794 @node Substitution function examples
3795 @subsection Substitution function examples
3797 This section introduces some substitution function examples.
3798 These are not intended to be exhaustive, but rather to demonstrate
3799 some of the possibilities of simple substitution functions.
3801 In the first example, a function is defined that simplifies
3802 setting the padding of a TextScript:
3804 @lilypond[quote,verbatim,ragged-right]
3806 #(define-music-function
3807 (parser location padding)
3810 \once \override TextScript #'padding = $padding
3814 c4^"piu mosso" b a b
3816 c4^"piu mosso" d e f
3818 c4^"piu mosso" fis a g
3822 In addition to numbers, we can use music expressions such
3823 as notes for arguments to music functions:
3825 @c TODO: use a better example (the music argument is redundant).
3827 @lilypond[quote,verbatim,ragged-right]
3829 #(define-music-function
3830 (parser location note)
3833 \once \override Voice.NoteHead #'stencil =
3834 #ly:text-interface::print
3835 \once \override Voice.NoteHead #'text =
3836 \markup \musicglyph #"custodes.mensural.u0"
3837 \once \override Voice.Stem #'stencil = ##f
3841 \relative c' { c4 d e f \custosNote g }
3844 Substitution functions with multiple arguments can be defined:
3846 @lilypond[quote,verbatim,ragged-right]
3848 #(define-music-function
3849 (parser location padding tempotext)
3852 \once \override Score.MetronomeMark #'padding = $padding
3853 \tempo \markup { \bold $tempotext }
3857 \tempo \markup { "Low tempo" }
3859 \tempoPadded #4.0 #"High tempo"
3864 @c TODO: add appropriate @@ref's here.