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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::
67 * Context layout order::
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
790 \override Flag #'transparent = ##t
794 \accepts "ImproVoice"
798 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
799 c4 c^"undress" c_"while playing :)" c }
805 These settings are defined within a @code{\context} block inside a
806 @code{\layout} block,
816 In the following discussion, the example input shown should go in place
817 of the @dots{} in the previous fragment.
819 First it is necessary to define a name for the new context:
825 Since it is similar to the @code{Voice}, we want commands that work
826 on (existing) @code{Voice}s to remain working. This is achieved by
827 giving the new context an alias @code{Voice},
833 The context will print notes and instructive texts, so we need to add
834 the engravers which provide this functionality,
837 \consists Note_heads_engraver
838 \consists Text_engraver
841 but we only need this on the center line,
844 \consists Pitch_squash_engraver
845 squashedPosition = #0
848 The @rinternals{Pitch_squash_engraver} modifies note heads (created
849 by @rinternals{Note_heads_engraver}) and sets their vertical
850 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
853 The notes look like a slash, and have no stem,
856 \override NoteHead #'style = #'slash
857 \override Stem #'transparent = ##t
858 \override Flag #'transparent = ##t
861 All these plug-ins have to cooperate, and this is achieved with a
862 special plug-in, which must be marked with the keyword @code{\type}.
863 This should always be @code{Engraver_group}.
866 \type "Engraver_group"
874 \type "Engraver_group"
875 \consists "Note_heads_engraver"
876 \consists "Text_engraver"
877 \consists Pitch_squash_engraver
878 squashedPosition = #0
879 \override NoteHead #'style = #'slash
880 \override Stem #'transparent = ##t
881 \override Flag #'transparent = ##t
887 Contexts form hierarchies. We want to hang the @code{ImproVoice}
888 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
889 modify the @code{Staff} definition with the @code{\accepts}
900 The opposite of @code{\accepts} is @code{\denies},
901 which is sometimes needed when reusing existing context definitions.
903 Putting both into a @code{\layout} block, like
913 \accepts "ImproVoice"
918 Then the output at the start of this subsection can be entered as
926 c c_"while playing :)"
933 @node Context layout order
934 @subsection Context layout order
936 @cindex contexts, layout order
940 Contexts are normally positioned in a system from top to bottom
941 in the order in which they are encountered in the input file. When
942 contexts are nested, the outer context will include inner nested
943 contexts as specified in the input file, provided the inner contexts
944 are included in the outer context's @qq{accepts} list. Nested
945 contexts which are not included in the outer context's @qq{accepts}
946 list will be repositioned below the outer context rather than nested
949 The @qq{accepts} list of a context can be changed with the
950 @code{\accepts} and @code{\denies} commands. @code{\accepts} adds a
951 context to the @qq{accepts} list and @code{\denies} removes a context
952 from the list. For example, it would not normally be desirable for
953 chord names to be nested within a @code{Staff} context, so the
954 @code{ChordNames} context is not included by default in the @qq{accepts}
955 list of the @code{Staff} context, but if this were to be required it can
958 @lilypond[verbatim,quote]
962 \chords { d1:m7 b1:min7.5- }
967 @lilypond[verbatim,quote]
971 \chords { d1:m7 b1:min7.5- }
976 \accepts "ChordNames"
982 @code{\denies} is mainly used when a new context is being based on
983 another, but the required nesting differs. For example, the
984 @code{VaticanaStaff} context is based on the @code{Staff} context, but
985 with the @code{VaticanaVoice} context substituted for the @code{Voice}
986 context in the @qq{accepts} list.
988 Note that a context will be silently created implicitly if a command
989 is encountered when there is no suitable context available to
990 contain it. This can give rise to unexpected new staves or scores.
994 @rprogram{An extra staff appears}.
997 @file{ly/engraver-init.ly}.
1001 @node Explaining the Internals Reference
1002 @section Explaining the Internals Reference
1006 * Navigating the program reference::
1007 * Layout interfaces::
1008 * Determining the grob property::
1009 * Naming conventions::
1012 @node Navigating the program reference
1013 @subsection Navigating the program reference
1015 @c TODO remove this (it's in the LM)
1016 @c Replace with more factual directions
1018 Suppose we want to move the fingering indication in the fragment
1021 @lilypond[quote,relative=2,verbatim]
1027 If you visit the documentation on fingering instructions (in
1028 @ref{Fingering instructions}), you will notice:
1033 Internals Reference: @rinternals{Fingering}.
1038 @c outdated info; probably will delete.
1040 This fragment points to two parts of the program reference: a page
1041 on @code{FingeringEvent} and one on @code{Fingering}.
1043 The page on @code{FingeringEvent} describes the properties of the music
1044 expression for the input @w{@code{-2}}. The page contains many links
1045 forward. For example, it says
1048 Accepted by: @rinternals{Fingering_engraver},
1052 That link brings us to the documentation for the Engraver, the
1056 This engraver creates the following layout objects: @rinternals{Fingering}.
1059 In other words, once the @code{FingeringEvent}s are interpreted, the
1060 @code{Fingering_engraver} plug-in will process them.
1064 @c I can't figure out what this is supposed to mean. -gp
1066 The @code{Fingering_engraver} is also listed to create
1067 @rinternals{Fingering} objects,
1069 @c old info? it doesn't make any sense to me with our current docs.
1071 second bit of information listed under @b{See also} in the Notation
1076 The programmer's reference is available as an HTML document. It is
1077 highly recommended that you read it in HTML form, either online or
1078 by downloading the HTML documentation. This section will be much more
1079 difficult to understand if you are using the
1083 Follow the link to @rinternals{Fingering}. At the top of the
1087 Fingering objects are created by: @rinternals{Fingering_engraver} and
1088 @rinternals{New_fingering_engraver}.
1091 By following related links inside the program reference, we can follow the
1092 flow of information within the program:
1096 @item @rinternals{Fingering}:
1097 @rinternals{Fingering} objects are created by:
1098 @rinternals{Fingering_engraver}
1100 @item @rinternals{Fingering_engraver}:
1101 Music types accepted: @rinternals{fingering-event}
1103 @item @rinternals{fingering-event}:
1104 Music event type @code{fingering-event} is in Music expressions named
1105 @rinternals{FingeringEvent}
1108 This path goes against the flow of information in the program: it
1109 starts from the output, and ends at the input event. You could
1110 also start at an input event, and read with the flow of
1111 information, eventually ending up at the output object(s).
1113 The program reference can also be browsed like a normal document. It
1114 contains chapters on
1116 @rinternals{Music definitions},
1119 @code{Music definitions}
1121 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1122 chapter lists all the definitions used and all properties that may be
1126 @node Layout interfaces
1127 @subsection Layout interfaces
1129 @cindex interface, layout
1130 @cindex layout interface
1133 The HTML page that we found in the previous section describes the
1134 layout object called @rinternals{Fingering}. Such an object is a
1135 symbol within the score. It has properties that store numbers (like
1136 thicknesses and directions), but also pointers to related objects. A
1137 layout object is also called a @emph{Grob}, which is short for Graphical
1138 Object. For more details about Grobs, see @rinternals{grob-interface}.
1140 The page for @code{Fingering} lists the definitions for the
1141 @code{Fingering} object. For example, the page says
1144 @code{padding} (dimension, in staff space):
1150 which means that the number will be kept at a distance of at least 0.5
1154 Each layout object may have several functions as a notational or
1155 typographical element. For example, the Fingering object
1156 has the following aspects
1160 Its size is independent of the horizontal spacing, unlike slurs or beams.
1163 It is a piece of text. Granted, it is usually a very short text.
1166 That piece of text is typeset with a font, unlike slurs or beams.
1169 Horizontally, the center of the symbol should be aligned to the
1170 center of the note head.
1173 Vertically, the symbol is placed next to the note and the staff.
1176 The vertical position is also coordinated with other superscript
1177 and subscript symbols.
1180 Each of these aspects is captured in so-called @emph{interface}s,
1181 which are listed on the @rinternals{Fingering} page at the bottom
1184 This object supports the following interfaces:
1185 @rinternals{item-interface},
1186 @rinternals{self-alignment-interface},
1187 @rinternals{side-position-interface}, @rinternals{text-interface},
1188 @rinternals{text-script-interface}, @rinternals{font-interface},
1189 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1192 Clicking any of the links will take you to the page of the respective
1193 object interface. Each interface has a number of properties. Some of
1194 them are not user-serviceable (@q{Internal properties}), but others
1197 We have been talking of @emph{the} @code{Fingering} object, but actually it
1198 does not amount to much. The initialization file (see
1199 @rlearning{Other sources of information})
1200 @file{scm/define-grobs.scm} shows the soul of the @q{object},
1205 (avoid-slur . around)
1206 (slur-padding . 0.2)
1207 (staff-padding . 0.5)
1208 (self-alignment-X . 0)
1209 (self-alignment-Y . 0)
1210 (script-priority . 100)
1211 (stencil . ,ly:text-interface::print)
1212 (direction . ,ly:script-interface::calc-direction)
1213 (font-encoding . fetaText)
1214 (font-size . -5) ; don't overlap when next to heads.
1215 (meta . ((class . Item)
1216 (interfaces . (finger-interface
1218 text-script-interface
1220 side-position-interface
1221 self-alignment-interface
1222 item-interface))))))
1226 As you can see, the @code{Fingering} object is nothing more than a
1227 bunch of variable settings, and the webpage in the Internals Reference
1228 is directly generated from this definition.
1231 @node Determining the grob property
1232 @subsection Determining the grob property
1234 @c TODO remove this (it's in the LM)
1235 @c Replace with more factual directions
1237 Recall that we wanted to change the position of the @b{2} in
1239 @lilypond[quote,relative=2,verbatim]
1245 Since the @b{2} is vertically positioned next to its note, we have to
1246 meddle with the interface associated with this positioning. This is
1247 done using @code{side-position-interface}. The page for this interface
1251 @code{side-position-interface}
1253 Position a victim object (this one) next to other objects (the
1254 support). The property @code{direction} signifies where to put the
1255 victim object relative to the support (left or right, up or down?)
1260 Below this description, the variable @code{padding} is described as
1265 (dimension, in staff space)
1267 Add this much extra space between objects that are next to each other.
1271 By increasing the value of @code{padding}, we can move the
1272 fingering away from the note head. The following command inserts
1273 3 staff spaces of white
1274 between the note and the fingering:
1276 \once \override Voice.Fingering #'padding = #3
1279 Inserting this command before the Fingering object is created,
1280 i.e., before @code{c2}, yields the following result:
1282 @lilypond[quote,relative=2,verbatim]
1283 \once \override Voice.Fingering #'padding = #3
1290 In this case, the context for this tweak is @code{Voice}. This
1291 fact can also be deduced from the program reference, for the page for
1292 the @rinternals{Fingering_engraver} plug-in says
1295 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1299 @node Naming conventions
1300 @subsection Naming conventions
1302 Another thing that is needed, is an overview of the various naming
1306 @item scheme functions: lowercase-with-hyphens (incl. one-word
1308 @item scheme functions: ly:plus-scheme-style
1309 @item music events, music classes and music properties:
1311 @item Grob interfaces: scheme-style
1312 @item backend properties: scheme-style (but X and Y!)
1313 @item contexts (and MusicExpressions and grobs): Capitalized or
1315 @item context properties: lowercaseFollowedByCamelCase
1317 Capitalized_followed_by_lowercase_and_with_underscores
1320 Questions to be answered:
1322 @item Which of these are conventions and which are rules?
1323 @item Which are rules of the underlying language, and which are
1327 @node Modifying properties
1328 @section Modifying properties
1330 @c TODO change the menu and subsection node names to use
1331 @c backslash once the new macro to handle the refs
1332 @c is available. Need to find and change all refs at
1333 @c the same time. -td
1336 * Overview of modifying properties::
1338 * The override command::
1339 * The tweak command::
1340 * set versus override::
1341 * Modifying alists::
1345 @node Overview of modifying properties
1346 @subsection Overview of modifying properties
1348 Each context is responsible for creating certain types of graphical
1349 objects. The settings used for printing these objects are also stored by
1350 context. By changing these settings, the appearance of objects can be
1353 There are two different kinds of properties stored in contexts:
1354 context properties and grob properties. Context properties are
1355 properties that apply to the context as a whole and control
1356 how the context itself is displayed. In contrast, grob properties
1357 apply to specific grob types that will be displayed in the context.
1359 The @code{\set} and @code{\unset} commands are used to change values
1360 for context properties. The @code{\override} and @code{\revert}
1361 commands are used to change values for grob properties.
1364 The syntax for this is
1367 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1370 Here @var{name} is the name of a graphical object, like
1371 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1372 variable of the formatting system (@q{grob property} or @q{layout
1373 property}). The latter is a symbol, so it must be quoted. The
1374 subsection @ref{Modifying properties}, explains what to fill in
1375 for @var{name}, @var{property}, and @var{value}. Here we only
1376 discuss the functionality of this command.
1381 \override Staff.Stem #'thickness = #4.0
1385 makes stems thicker (the default is 1.3, with staff line thickness as a
1386 unit). Since the command specifies @code{Staff} as context, it only
1387 applies to the current staff. Other staves will keep their normal
1388 appearance. Here we see the command in action:
1390 @lilypond[quote,verbatim,relative=2]
1392 \override Staff.Stem #'thickness = #4.0
1398 The @code{\override} command changes the definition of the @code{Stem}
1399 within the current @code{Staff}. After the command is interpreted
1400 all stems are thickened.
1402 Analogous to @code{\set}, the @var{context} argument may be left out,
1403 causing the default context @code{Voice} to be used. Adding
1404 @code{\once} applies the change during one timestep only.
1406 @lilypond[quote,verbatim,relative=2]
1408 \once \override Stem #'thickness = #4.0
1413 The @code{\override} must be done before the object is
1414 started. Therefore, when altering @emph{Spanner} objects such as slurs
1415 or beams, the @code{\override} command must be executed at the moment
1416 when the object is created. In this example,
1418 @lilypond[quote,verbatim,relative=2]
1419 \override Slur #'thickness = #3.0
1421 \override Beam #'beam-thickness = #0.6
1426 the slur is fatter but the beam is not. This is because the command for
1427 @code{Beam} comes after the Beam is started, so it has no effect.
1429 Analogous to @code{\unset}, the @code{\revert} command for a context
1430 undoes an @code{\override} command; like with @code{\unset}, it only
1431 affects settings that were made in the same context. In other words, the
1432 @code{\revert} in the next example does not do anything.
1435 \override Voice.Stem #'thickness = #4.0
1436 \revert Staff.Stem #'thickness
1439 Some tweakable options are called @q{subproperties} and reside inside
1440 properties. To tweak those, use commands of the form
1442 @c leave this as a long long
1444 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1451 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1458 @rinternals{Backend},
1459 @rinternals{All layout objects},
1460 @rinternals{OverrideProperty},
1461 @rinternals{RevertProperty},
1462 @rinternals{PropertySet}.
1467 The back-end is not very strict in type-checking object properties.
1468 Cyclic references in Scheme values for properties can cause hangs
1469 or crashes, or both.
1473 @node The set command
1474 @subsection The @code{@bs{}set} command
1478 @cindex changing properties
1480 Each context has a set of @emph{properties}, variables contained
1481 in that context. Context properties are changed with the @code{\set}
1482 command, which has the following syntax:
1485 \set @var{context}.@var{property} = #@var{value}
1488 @var{value} is a Scheme object, which is why it must be preceded by
1489 the @code{#}@tie{}character.
1491 Contexts properties are usually named in
1492 @code{studlyCaps}. They mostly control the translation from
1493 music to notation, e.g. @code{localKeySignature} (for determining
1494 whether to print accidentals), or @code{measurePosition} (for
1495 determining when to print a bar line). Context properties can
1496 change value over time while interpreting a piece of music;
1497 @code{measurePosition} is an obvious example of
1498 this. Context properties are modified with @code{\set}.
1500 For example, multimeasure rests will be combined into a single bar
1501 if the context property @code{skipBars} is set to @code{#t}:
1503 @lilypond[quote,verbatim,relative=2]
1505 \set Score.skipBars = ##t
1509 If the @var{context} argument is left out, then the property will be
1510 set in the current bottom context (typically @code{ChordNames},
1511 @code{Voice}, @code{TabVoice}, or @code{Lyrics}).
1513 @lilypond[quote,verbatim,relative=2]
1514 \set Score.autoBeaming = ##f
1518 \set autoBeaming = ##t
1526 The change is applied @q{on-the-fly}, during the music, so that the
1527 setting only affects the second group of eighth notes.
1529 Note that the bottom-most context does not always contain the property
1530 that you wish to change -- for example, attempting to set the
1531 @code{skipBars} property of the default bottom context, in this case
1532 @code{Voice}, will have no effect, because skipBars is a property of
1533 the @code{Score} context.
1535 @lilypond[quote,verbatim,relative=2]
1541 Contexts are hierarchical, so if an enclosing context was specified, for
1542 example @code{Staff}, then the change would also apply to all
1543 @code{Voice}s in the current staff.
1547 The @code{\unset} command:
1550 \unset @var{context}.@var{property}
1554 is used to remove the definition of @var{property} from
1555 @var{context}. This command removes
1556 the definition only if it is set in @var{context}.
1557 Properties that have been set in enclosing contexts will
1558 not be altered by an unset in an enclosed context:
1560 @lilypond[quote,verbatim,relative=2]
1561 \set Score.autoBeaming = ##t
1566 \unset Score.autoBeaming
1574 Like @code{\set}, the @var{context} argument does not have to be
1575 specified for a bottom context, so the two statements
1578 \set Voice.autoBeaming = ##t
1579 \set autoBeaming = ##t
1583 are equivalent if the current bottom context is @code{Voice}.
1587 Preceding a @code{\set} command by @code{\once} makes the
1588 setting apply to only a single time-step:
1590 @lilypond[quote,verbatim,relative=2]
1592 \once \set fontSize = #4.7
1597 A full description of all available context properties is in the
1598 internals reference, see
1600 @rinternals{Tunable context properties}.
1603 Translation @expansion{} Tunable context properties.
1608 Internals Reference:
1610 @rinternals{Tunable context properties}.
1613 @cindex grob properties
1614 @cindex properties, grob
1618 @node The override command
1619 @subsection The @code{\override} command
1621 There is a special type of context property: the grob
1622 description. Grob descriptions are named in @code{StudlyCaps}
1623 (starting with capital letters). They contain the
1624 @q{default settings} for a particular kind of grob as an
1625 association list. See @file{scm/define-grobs.scm}
1626 to see the settings for each grob description. Grob descriptions
1627 are modified with @code{\override}.
1629 @code{\override} is actually a shorthand;
1632 \override @var{context}.@var{GrobName} #'@var{property} = #@var{value}
1636 is more or less equivalent to
1638 @c leave this long line -gp
1640 \set @var{context}.@var{GrobName} =
1641 #(cons (cons '@var{property} @var{value})
1642 <previous value of @var{context}.@var{GrobName}>)
1645 The value of @code{context}.@code{GrobName} (the alist) is used to initialize
1646 the properties of individual grobs. Grobs have
1647 properties, named in Scheme style, with
1648 @code{dashed-words}. The values of grob properties change
1649 during the formatting process: formatting basically amounts
1650 to computing properties using callback functions.
1652 For example, we can increase the thickness of a note stem by
1653 overriding the @code{thickness} property of the @code{Stem}
1656 @lilypond[quote,verbatim,relative=2]
1658 \override Voice.Stem #'thickness = #3.0
1662 If no context is specified in an @code{\override}, the bottom
1665 @lilypond[quote,verbatim,relative=2]
1666 { \override Staff.Stem #'thickness = #3.0
1670 \override Stem #'thickness = #0.5
1680 @cindex reverting overrides
1681 @cindex overrides, reverting
1683 The effects of @code{\override} can be undone by @code{\revert}:
1685 @lilypond[quote,verbatim,relative=2]
1687 \override Voice.Stem #'thickness = #3.0
1689 \revert Voice.Stem #'thickness
1693 The effects of @code{\override} and @code{\revert} apply to all
1694 grobs in the affected context from the current time forward:
1696 @lilypond[quote,verbatim,relative=2]
1701 \override Staff.Stem #'thickness = #3.0
1705 \revert Staff.Stem #'thickness
1713 @cindex overriding for only one moment
1715 @code{\once} can be used with @code{\override}
1716 to affect only the current time step:
1718 @lilypond[quote,verbatim,relative=2]
1722 \override Stem #'thickness = #3.0
1726 \once \override Stem #'thickness = #3.0
1735 Commands which change output generally look like
1738 \override Voice.Stem #'thickness = #3.0
1742 To construct this tweak we must determine these bits of information:
1745 @item the context: here @code{Voice}.
1746 @item the layout object: here @code{Stem}.
1747 @item the layout property: here @code{thickness}.
1748 @item a sensible value: here @code{3.0}.
1751 Some tweakable options are called @q{subproperties} and reside inside
1752 properties. To tweak those, use commands in the form
1755 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1758 @cindex internal documentation
1759 @cindex finding graphical objects
1760 @cindex graphical object descriptions
1763 @cindex internal documentation
1765 For many properties, regardless of the data type of the property, setting the
1766 property to false (@code{#f}) will result in turning it off, causing
1767 LilyPond to ignore that property entirely. This is particularly useful for
1768 turning off grob properties which may otherwise be causing problems.
1770 We demonstrate how to glean this information from the notation manual
1771 and the program reference.
1776 Internals Reference:
1777 @rinternals{Backend}
1779 @node The tweak command
1780 @subsection The @code{\tweak} command
1785 Changing grob properties
1786 with @code{\override} causes the changes to apply to all of the
1787 given grobs in the context at the moment the change applies.
1788 Sometimes, however, it is desirable to have changes apply to just
1789 one grob, rather than to all grobs in the affected context. This is
1790 accomplished with the @code{\tweak} command, which has the following
1794 \tweak #'@code{grob-property} #@code{value}
1797 The @code{\tweak} command applies to the object that immediately
1798 follows @code{value} in the music stream.
1801 In some cases, it is possible to take a short-cut for tuning
1802 graphical objects. For objects that are created directly from
1803 an item in the input file, you can use the @code{\tweak} command.
1806 @lilypond[relative=2,verbatim,quote]
1811 \tweak #'duration-log #1
1814 -\tweak #'padding #8
1820 But the main use of the @code{\tweak} command is to modify just
1821 one of a number of notation elements which start at the same musical
1822 moment, like the notes of a chord, or tuplet brackets which start
1825 The @code{\tweak} command sets a property in the following object
1826 directly, without requiring the grob name or context to be
1827 specified. For this to work, it is necessary for the @code{\tweak}
1828 command to remain immediately adjacent to the object to which it is
1829 to apply after the input file has been converted to a music stream.
1830 This is often not the case, as many additional elements are inserted
1831 into the music stream implicitly. For example, when a note which is
1832 not part of a chord is processed, LilyPond implicitly inserts a
1833 @code{ChordEvent} event before the note, so separating the tweak
1834 from the note. However, if chord symbols are placed round the
1835 tweak and the note, the @code{\tweak} command comes after the
1836 @code{ChordEvent} in the music stream, so remaining adjacent to the
1837 note, and able to modify it.
1841 @lilypond[relative=2,verbatim,quote]
1842 <\tweak #'color #red c>4
1848 @lilypond[relative=2,verbatim,quote]
1849 \tweak #'color #red c4
1854 For an introduction to the syntax and uses of the tweak command
1855 see @rlearning{Tweaking methods}.
1857 When several similar items are placed at the same musical moment,
1858 the @code{\override} command cannot be used to modify just one of
1859 them -- this is where the @code{\tweak} command must be used.
1860 Items which may appear more than once at the same musical moment
1861 include the following:
1863 @c TODO expand to include any further uses of \tweak
1865 @item note heads of notes inside a chord
1866 @item articulation signs on a single note
1867 @item ties between notes in a chord
1868 @item tuplet brackets starting at the same time
1871 @c TODO add examples of these
1873 @cindex chord, modifying one note in
1875 In this example, the color of one note head and the type of another
1876 note head are modified within a single chord:
1878 @lilypond[relative=2,verbatim,quote]
1883 \tweak #'duration-log #1
1888 @code{\tweak} can be used to modify slurs:
1890 @lilypond[verbatim,quote,relative=1]
1891 c-\tweak #'thickness #5 ( d e f)
1895 For the @code{\tweak} command to work, it must
1896 remain immediately adjacent to the object to which it is
1897 to apply after the input file has been converted to a music stream.
1898 At times, LilyPond may insert additional items into the music stream
1899 during the parsing process. For example, when a note that is not
1900 explicitly part of a chord will be placed in a chord by LilyPond,
1901 so notes to be modified with @code{\tweak} must be placed inside
1904 @lilypond[relative=2,verbatim,quote]
1905 \tweak #'color #red c4
1906 <\tweak #'color #red c>4
1909 The @code{\tweak} command cannot be used to modify any item
1910 that does not appear explicitly in the input file. In particular
1911 it cannot be used to modify stems,
1912 beams or accidentals directly, since these are generated later by
1913 note heads, rather than by music elements in the input stream.
1914 Nor can @code{\tweak} be used to modify clefs or time
1915 signatures, since these become separated from any preceding
1916 @code{\tweak} command in the input stream by the automatic
1917 insertion of extra elements required to specify the context.
1919 Several @code{\tweak} commands may be placed before a
1920 notational element -- all affect it:
1922 @lilypond[verbatim,quote,relative=1]
1924 -\tweak #'style #'dashed-line
1925 -\tweak #'dash-fraction #0.2
1926 -\tweak #'thickness #3
1927 -\tweak #'color #red
1932 The music stream which is generated from a section of an input file,
1933 including any automatically inserted elements, may be examined,
1934 see @rextend{Displaying music expressions}. This may be helpful in
1935 determining what may be modified by a @code{\tweak} command, or
1936 in determining how to adjust the input to make a @code{\tweak}
1942 @rlearning{Tweaking methods}.
1945 @rextend{Displaying music expressions}.
1950 @cindex tweaks in a variable
1951 The @code{\tweak} command cannot be used inside a variable.
1953 @cindex tweaks in lyrics
1954 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1956 @cindex tweaking control points
1957 @cindex control points, tweaking
1959 The @code{\tweak} command will apply to only the first of several
1960 generated ties in a chord.
1962 @node set versus override
1963 @subsection @code{\set} vs. @code{\override}
1965 @c TODO -- This section is probably unnecessary now.
1968 We have seen two methods of changing properties: @code{\set} and
1969 @code{\override}. There are actually two different kinds of
1972 @code{fontSize} is a special property: it is equivalent to
1973 entering @code{\override ... #'font-size} for all pertinent
1974 objects. Since this is a common change, the special
1975 property (modified with @code{\set}) was created.
1980 @node Modifying alists
1981 @subsection Modifying alists
1983 Some user-configurable properties are internally represented as
1984 @emph{alists} (association lists), which store pairs of
1985 @emph{keys} and @emph{values}. The structure of an alist is:
1988 '((@var{key1} . @var{value1})
1989 (@var{key2} . @var{value2})
1990 (@var{key3} . @var{value3})
1994 If an alist is a grob property or @code{\paper} variable, its keys
1995 can be modified individually without affecting other keys.
1997 For example, to reduce the space between adjacent staves in a
1998 staff-group, use the @code{staff-staff-spacing} property of the
1999 @code{StaffGrouper} grob. The property is an alist with four
2000 keys: @code{basic-distance}, @code{minimum-distance},
2001 @code{padding}, and @code{stretchability}. The standard settings
2002 for this property are listed in the @qq{Backend} section of the
2003 Internals Reference (see @rinternals{StaffGrouper}):
2006 '((basic-distance . 9)
2007 (minimum-distance . 7)
2009 (stretchability . 5))
2012 One way to bring the staves closer together is by reducing the
2013 value of the @code{basic-distance} key (@code{9}) to match the
2014 value of @code{minimum-distance} (@code{7}). To modify a single
2015 key individually, use a @emph{nested declaration}:
2017 @lilypond[quote,verbatim]
2018 % default space between staves
2020 \new Staff { \clef treble c''1 }
2021 \new Staff { \clef bass c1 }
2024 % reduced space between staves
2025 \new PianoStaff \with {
2026 % this is the nested declaration
2027 \override StaffGrouper #'staff-staff-spacing #'basic-distance = #7
2029 \new Staff { \clef treble c''1 }
2030 \new Staff { \clef bass c1 }
2034 Using a nested declaration will update the specified key (such as
2035 @code{basic-distance} in the above example) without altering any
2036 other keys already set for the same property.
2038 Now suppose we want the staves to be as close as possible without
2039 overlapping. The simplest way to do this is to set all four alist
2040 keys to zero. However, it is not necessary to enter four nested
2041 declarations, one for each key. Instead, the property can be
2042 completely re-defined with one declaration, as an alist:
2044 @lilypond[quote,verbatim]
2045 \new PianoStaff \with {
2046 \override StaffGrouper #'staff-staff-spacing =
2047 #'((basic-distance . 0)
2048 (minimum-distance . 0)
2050 (stretchability . 0))
2052 \new Staff { \clef treble c''1 }
2053 \new Staff { \clef bass c1 }
2057 Note that any keys not explicitly listed in the alist definition
2058 will be reset to their @emph{default-when-unset} values. In the
2059 case of @code{staff-staff-spacing}, any unset key-values would be
2060 reset to zero (except @code{stretchability}, which takes the value
2061 of @code{basic-distance} when unset). Thus the following two
2062 declarations are equivalent:
2065 \override StaffGrouper #'staff-staff-spacing =
2066 #'((basic-distance . 7))
2068 \override StaffGrouper #'staff-staff-spacing =
2069 #'((basic-distance . 7)
2070 (minimum-distance . 0)
2072 (stretchability . 7))
2075 One (possibly unintended) consequence of this is the removal of
2076 any standard settings that are set in an initialization file and
2077 loaded each time an input file is compiled. In the above example,
2078 the standard settings for @code{padding} and
2079 @code{minimum-distance} (defined in @file{scm/define-grobs.scm})
2080 are reset to their default-when-unset values (zero for both keys).
2081 Defining a property or variable as an alist (of any size) will
2082 always reset all unset key-values to their default-when-unset
2083 values. Unless this is the intended result, it is safer to update
2084 key-values individually with a nested declaration.
2086 @warning{Nested declarations will not work for context property
2087 alists (such as @code{beamExceptions}, @code{keySignature},
2088 @code{timeSignatureSettings}, etc.). These properties can only be
2089 modified by completely re-defining them as alists.}
2092 @node Useful concepts and properties
2093 @section Useful concepts and properties
2098 * Direction and placement::
2099 * Distances and measurements::
2100 * Staff symbol properties::
2102 * Visibility of objects::
2104 * Rotating objects::
2108 @subsection Input modes
2110 The way in which the notation contained within an input file is
2111 interpreted is determined by the current input mode.
2115 This is activated with the @code{\chordmode} command, and causes
2116 input to be interpreted with the syntax of chord notation, see
2117 @ref{Chord notation}. Chords are rendered as notes on a staff.
2119 Chord mode is also activated with the @code{\chords} command.
2120 This also creates a new @code{ChordNames} context and
2121 causes the following input to be interpreted with the syntax of
2122 chord notation and rendered as chord names in the @code{ChordNames}
2123 context, see @ref{Printing chord names}.
2127 This is activated with the @code{\drummode} command, and causes
2128 input to be interpreted with the syntax of drum notation, see
2129 @ref{Basic percussion notation}.
2131 Drum mode is also activated with the @code{\drums} command.
2132 This also creates a new @code{DrumStaff} context and causes the
2133 following input to be interpreted with the syntax of drum notation
2134 and rendered as drum symbols on a drum staff, see @ref{Basic
2135 percussion notation}.
2137 @strong{Figure mode}
2139 This is activated with the @code{\figuremode} command, and causes
2140 input to be interpreted with the syntax of figured bass, see
2141 @ref{Entering figured bass}.
2143 Figure mode is also activated with the @code{\figures} command.
2144 This also creates a new @code{FiguredBass} context and causes the
2145 following input to be interpreted with the figured bass syntax
2146 and rendered as figured bass symbols in the @code{FiguredBass}
2147 context, see @ref{Introduction to figured bass}.
2149 @strong{Fret and tab modes}
2151 There are no special input modes for entering fret and tab symbols.
2153 To create tab diagrams, enter notes or chords in note mode and
2154 render them in a @code{TabStaff} context, see
2155 @ref{Default tablatures}.
2157 To create fret diagrams above a staff, you have two choices.
2158 You can either use the @code{FretBoards} context (see
2159 @ref{Automatic fret diagrams} or you can enter them as a markup
2160 above the notes using the @code{\fret-diagram} command (see
2161 @ref{Fret diagram markups}).
2163 @strong{Lyrics mode}
2165 This is activated with the @code{\lyricmode} command, and causes
2166 input to be interpreted as lyric syllables with optional durations
2167 and associated lyric modifiers, see @ref{Vocal music}.
2169 Lyric mode is also activated with the @code{\addlyrics} command.
2170 This also creates a new @code{Lyrics} context and an implicit
2171 @code{\lyricsto} command which associates the following lyrics
2172 with the preceding music.
2174 @strong{Markup mode}
2176 This is activated with the @code{\markup} command, and causes
2177 input to be interpreted with the syntax of markup, see
2178 @ref{Text markup commands}.
2180 @c silly work-around for texinfo broken-ness
2181 @c (@strong{Note...} causes a spurious cross-reference in Info)
2184 This is the default mode or it may be activated with the
2185 @code{\notemode} command. Input is interpreted as pitches,
2186 durations, markup, etc and typeset as musical notation on a staff.
2188 It is not normally necessary to specify note mode explicitly, but
2189 it may be useful to do so in certain situations, for example if you
2190 are in lyric mode, chord mode or any other mode and want to insert
2191 something that only can be done with note mode syntax.
2193 For example, to indicate dynamic markings for the verses of a
2194 choral pieces it is necessary to enter note mode to interpret
2197 @lilypond[verbatim,relative=2,quote]
2200 \notemode{\set stanza = \markup{ \dynamic f 1. } }
2204 \notemode{\set stanza = \markup{ \dynamic p 2. } }
2211 @node Direction and placement
2212 @subsection Direction and placement
2214 In typesetting music the direction and placement of many items is
2215 a matter of choice. For example, the stems of notes can
2216 be directed up or down; lyrics, dynamics, and other expressive
2217 marks may be placed above or below the staff; text may be aligned
2218 left, right or center; etc. Most of these choices may be left to
2219 be determined automatically by LilyPond, but in some cases it may
2220 be desirable to force a particular direction or placement.
2222 @strong{Articulation direction indicators}
2224 By default some directions are always up or always down (e.g.
2225 dynamics or fermata), while other things can alternate between
2226 up or down based on the stem direction (like slurs or accents).
2228 @c TODO Add table showing these
2230 The default action may be overridden by prefixing the articulation
2231 by a @emph{direction indicator}. Three direction indicators are
2232 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
2233 and @code{-} (meaning @qq{use default direction}). The direction
2234 indicator can usually be omitted, in which case @code{-} is assumed,
2235 but a direction indicator is @strong{always} required before
2238 @item @code{\tweak} commands
2239 @item @code{\markup} commands
2240 @item @code{\tag} commands
2241 @item string markups, e.g. -"string"
2242 @item fingering instructions, e.g. @w{@code{-1}}
2243 @item articulation shortcuts, e.g. @w{@code{-.}}, @w{@code{->}}, @w{@code{--}}
2246 Direction indicators affect only the next note:
2248 @lilypond[verbatim,quote,relative=2]
2255 @strong{The direction property}
2257 The position or direction of many layout objects is controlled
2258 by the @code{direction} property.
2260 The value of the @code{direction} property may be
2261 set to @code{1}, meaning @qq{up} or @qq{above}, or to @w{@code{-1}},
2262 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
2263 @code{DOWN} may be used instead of @code{1} and @w{@code{-1}}
2264 respectively. The default direction may be specified by setting
2265 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
2266 in many cases predefined commands
2267 exist to specify the direction. These are all of the form
2270 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
2273 where @code{xxxNeutral} means @qq{use the default direction}.
2274 See @rlearning{Within-staff objects}.
2276 In a few cases, arpeggio being the only common example, the value
2277 of the @code{direction} property specifies whether the object
2278 is to be placed to the right or left of the parent object. In
2279 this case @w{@code{-1}} or @code{LEFT} means @qq{to the left} and
2280 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
2281 or @code{CENTER} means @qq{use the default} direction, as before.
2284 These all have side-axis set to #X
2285 AmbitusAccidental - direction has no effect
2287 StanzaNumber - not tried
2288 TrillPitchAccidental - not tried
2289 TrillPitchGroup - not tried
2292 These indications affect all notes until they are cancelled.
2294 @lilypond[verbatim,quote,relative=2]
2304 @node Distances and measurements
2305 @subsection Distances and measurements
2307 @cindex distances, absolute
2308 @cindex distances, scaled
2315 Distances in LilyPond are of two types: absolute and scaled.
2317 Absolute distances are used for specifying margins, indents, and
2318 other page layout details, and are by default specified in
2319 millimeters. Distances may be specified in other units by
2320 following the quantity by @code{\mm}, @code{\cm},
2321 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27 of
2322 an inch). Page layout distances can also be specified in scalable
2323 units (see the following paragraph) by appending
2324 @code{\staff-space} to the quantity. Page layout is described in
2325 detail in @ref{Page layout}.
2327 Scaled distances are always specified in units of the staff-space
2328 or, rarely, the half staff-space. The staff-space is the distance
2329 between two adjacent staff lines. The default value can be changed
2330 globally by setting the global staff size, or it can be overridden
2331 locally by changing the @code{staff-space} property of
2332 @code{StaffSymbol}. Scaled distances automatically scale with any
2333 change to the either the global staff size or the
2334 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2335 automatically only with changes to the global staff size.
2336 The global staff size thus enables the overall size of a rendered
2337 score to be easily varied. For the methods of setting the global
2338 staff size see @ref{Setting the staff size}.
2342 If just a section of a score needs to be rendered to a different
2343 scale, for example an ossia section or a footnote, the global staff
2344 size cannot simply be changed as this would affect the entire score.
2345 In such cases the change in size is made by overriding both the
2346 @code{staff-space} property of @code{StaffSymbol} and the size of
2347 the fonts. A Scheme function, @code{magstep}, is available to
2348 convert from a font size change to the equivalent change in
2349 @code{staff-space}. For an explanation and an example of its use,
2350 see @rlearning{Length and thickness of objects}.
2355 @rlearning{Length and thickness of objects}.
2359 @ref{Setting the staff size}.
2362 @node Staff symbol properties
2363 @subsection Staff symbol properties
2365 @cindex adjusting staff symbol
2366 @cindex drawing staff symbol
2367 @cindex staff symbol, setting of
2369 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2370 @c Need to think of uses for these properties. Eg 'line-positions
2371 @c is used in a snippet to thicken centre line.
2372 @c If retained, add @ref to here in 1.6.2 -td
2374 The vertical position of staff lines and the number of staff lines
2375 can be defined at the same time. As the following example shows,
2376 note positions are not influenced by the staff line positions.
2378 @warning{The @code{'line-positions} property overrides the
2379 @code{'line-count} property. The number of staff lines is
2380 implicitly defined by the number of elements in the list of values
2381 for @code{'line-positions}.}
2383 @lilypond[verbatim,quote,relative=1]
2385 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
2390 The width of a staff can be modified. The units are staff
2391 spaces. The spacing of objects inside the staff is not affected by
2394 @lilypond[verbatim,quote,relative=1]
2396 \override StaffSymbol #'width = #23
2403 @subsection Spanners
2405 Many objects of musical notation extend over several notes or even
2406 several bars. Examples are slurs, beams, tuplet brackets, volta
2407 repeat brackets, crescendi, trills, and glissandi. Such objects
2408 are collectively called @qq{spanners}, and have special properties to control
2409 their appearance and behaviour. Some of these properties are common
2410 to all spanners; others are restricted to a sub-set of the spanners.
2412 All spanners support the @code{spanner-interface}. A few, essentially
2413 those that draw a straight line between the two objects, support in
2414 addition the @code{line-spanner-interface}.
2416 @unnumberedsubsubsec Using the @code{spanner-interface}
2418 This interface provides two properties that apply to several spanners.
2420 @strong{@i{The @code{minimum-length} property}}
2422 The minimum length of the spanner is specified by the
2423 @code{minimum-length} property. Increasing this usually has the
2424 necessary effect of increasing the spacing of the notes between the
2425 two end points. However, this override has no effect on
2426 many spanners, as their length is determined by other considerations.
2427 A few examples where it is effective are shown below.
2437 Works as long as callback is made:
2441 Works not at all for:
2450 @lilypond[verbatim,quote,relative=2]
2453 % increase the length of the tie
2454 -\tweak #'minimum-length #5
2458 @lilypond[verbatim,quote,relative=2]
2460 \compressFullBarRests
2462 % increase the length of the rest bar
2463 \once \override MultiMeasureRest #'minimum-length = #20
2468 @lilypond[verbatim,quote,relative=2]
2470 % increase the length of the hairpin
2471 \override Hairpin #'minimum-length = #20
2475 This override can also be used to increase the length of slurs and
2478 @lilypond[verbatim,quote,relative=2]
2481 -\tweak #'minimum-length #5
2486 -\tweak #'minimum-length #5
2490 For some layout objects, the @code{minimum-length} property becomes
2491 effective only if the @code{set-spacing-rods} procedure is called
2492 explicitly. To do this, the @code{springs-and-rods} property should
2493 be set to @code{ly:spanner::set-spacing-rods}. For example,
2494 the minimum length of a glissando has no effect unless the
2495 @code{springs-and-rods} property is set:
2497 @lilypond[verbatim,quote,relative=1]
2501 % not effective alone
2502 \once \override Glissando #'minimum-length = #20
2505 % effective only when both overrides are present
2506 \once \override Glissando #'minimum-length = #20
2507 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2511 The same is true of the @code{Beam} object:
2513 @lilypond[verbatim,quote,relative=1]
2514 % not effective alone
2515 \once \override Beam #'minimum-length = #20
2518 % effective only when both overrides are present
2519 \once \override Beam #'minimum-length = #20
2520 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2524 @strong{@i{The @code{to-barline} property}}
2526 The second useful property of the @code{spanner-interface} is
2527 @code{to-barline}. By default this is true, causing hairpins and
2528 other spanners which are terminated on the first note of a measure to
2529 end instead on the immediately preceding bar line. If set to false,
2530 the spanner will extend beyond the bar line and end on the note
2533 @lilypond[verbatim,quote,relative=2]
2534 a \< a a a a \! a a a \break
2535 \override Hairpin #'to-barline = ##f
2536 a \< a a a a \! a a a
2539 This property is not effective for all spanners. For example,
2540 setting it to @code{#t} has no effect on slurs or phrasing slurs
2541 or on other spanners for which terminating on the bar line would
2544 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2546 Objects which support the @code{line-spanner-interface} include
2549 @item @code{DynamicTextSpanner}
2550 @item @code{Glissando}
2551 @item @code{TextSpanner}
2552 @item @code{TrillSpanner}
2553 @item @code{VoiceFollower}
2556 The routine responsible for drawing the stencils for these spanners is
2557 @code{ly:line-interface::print}. This routine determines the
2558 exact location of the two end points and draws a line
2559 between them, in the style requested. The locations of the two
2560 end points of the spanner are computed on-the-fly, but it is
2561 possible to override their Y-coordinates. The
2562 properties which need to be specified are nested
2563 two levels down within the property hierarchy, but the syntax of
2564 the @code{\override} command is quite simple:
2566 @lilypond[relative=2,quote,verbatim]
2568 \once \override Glissando #'(bound-details left Y) = #3
2569 \once \override Glissando #'(bound-details right Y) = #-2
2573 The units for the @code{Y} property are @code{staff-space}s,
2574 with the center line of the staff being the zero point.
2575 For the glissando, this is the value for @code{Y} at the
2576 X-coordinate corresponding to the center point of each note head,
2577 if the line is imagined to be extended to there.
2579 If @code{Y} is not set, the value is computed from the vertical
2580 position of the corresponding attachment point of the spanner.
2582 In case of a line break, the values for the end points are
2583 specified by the @code{left-broken} and @code{right-broken}
2584 sub-lists of @code{bound-details}. For example:
2586 @lilypond[relative=2,ragged-right,verbatim,quote]
2587 \override Glissando #'breakable = ##t
2588 \override Glissando #'(bound-details right-broken Y) = #-3
2589 c1 \glissando \break
2594 A number of further properties of the @code{left} and
2595 @code{right} sub-lists of the @code{bound-details} property
2596 may be modified in the same way as @code{Y}:
2600 This sets the Y-coordinate of the end point, in @code{staff-space}s
2601 offset from the staff center line. By default, it is the center of
2602 the bound object, so a glissando points to the vertical center of
2605 For horizontal spanners, such as text spanners and trill spanners,
2606 it is hardcoded to 0.
2609 This determines where the line starts and ends in the X-direction,
2610 relative to the bound object. So, a value of @w{@code{-1}} (or
2611 @code{LEFT}) makes the line start/end at the left side of the note
2612 head it is attached to.
2615 This is the absolute X-coordinate of the end point. It is usually
2616 computed on the fly, and overriding it has little useful effect.
2619 Line spanners may have symbols at the beginning or end, which is
2620 contained in this sub-property. This is for internal use; it is
2621 recommended that @code{text} be used instead.
2624 This is a markup that is evaluated to yield the stencil. It is used
2625 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2627 @lilypond[quote,ragged-right,relative=2,verbatim]
2628 \override TextSpanner #'(bound-details left text)
2629 = \markup { \small \bold Slower }
2630 c2\startTextSpan b c a\stopTextSpan
2633 @item stencil-align-dir-y
2634 @item stencil-offset
2635 Without setting one of these, the stencil is simply put at the
2636 end-point, centered on the line, as defined by the @code{X} and
2637 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2638 or @code{stencil-offset} will move the symbol at the edge vertically
2639 relative to the end point of the line:
2641 @lilypond[relative=1,quote,verbatim]
2642 \override TextSpanner
2643 #'(bound-details left stencil-align-dir-y) = #-2
2644 \override TextSpanner
2645 #'(bound-details right stencil-align-dir-y) = #UP
2647 \override TextSpanner
2648 #'(bound-details left text) = #"ggg"
2649 \override TextSpanner
2650 #'(bound-details right text) = #"hhh"
2651 c4^\startTextSpan c c c \stopTextSpan
2654 Note that negative values move the text @emph{up}, contrary to the
2655 effect that might be expected, as a value of @w{@code{-1}} or
2656 @code{DOWN} means align the @emph{bottom} edge of the text with
2657 the spanner line. A value of @code{1} or @code{UP} aligns
2658 the top edge of the text with the spanner line.
2661 Setting this sub-property to @code{#t} produces an arrowhead at the
2665 This sub-property controls the space between the specified
2666 end point of the line and the actual end. Without padding, a
2667 glissando would start and end in the center of each note head.
2671 The music function @code{\endSpanners} terminates the spanner
2672 which starts on the immediately following note prematurely. It
2673 is terminated after exactly one note, or at the following bar line
2674 if @code{to-barline} is true and a bar line occurs before the next
2677 @lilypond[verbatim,quote,ragged-right,relative=2]
2679 c2 \startTextSpan c2 c2
2684 When using @code{\endSpanners} it is not necessary to close
2685 \startTextSpan with \stopTextSpan, nor is it necessary to close
2686 hairpins with @code{\!}.
2690 Internals Reference:
2691 @rinternals{TextSpanner},
2692 @rinternals{Glissando},
2693 @rinternals{VoiceFollower},
2694 @rinternals{TrillSpanner},
2695 @rinternals{line-spanner-interface}.
2698 @node Visibility of objects
2699 @subsection Visibility of objects
2701 @cindex objects, visibility of
2702 @cindex grobs, visibility of
2703 @cindex visibility of objects
2705 There are four main ways in which the visibility of layout objects
2706 can be controlled: their stencil can be removed, they can be made
2707 transparent, they can be colored white, or their
2708 @code{break-visibility} property can be overridden. The first
2709 three apply to all layout objects; the last to just a few -- the
2710 @emph{breakable} objects. The Learning Manual introduces these
2711 four techniques, see @rlearning{Visibility and color of objects}.
2713 There are also a few other techniques which are specific to
2714 certain layout objects. These are covered under Special
2718 * Removing the stencil::
2719 * Making objects transparent::
2720 * Painting objects white::
2721 * Using break-visibility::
2722 * Special considerations::
2726 @node Removing the stencil
2727 @unnumberedsubsubsec Removing the stencil
2729 @cindex stencil, removing
2731 Every layout object has a stencil property. By default this is set
2732 to the specific function which draws that object. If this property
2733 is overridden to @code{#f} no function will be called and the object
2734 will not be drawn. The default action can be recovered with
2737 @lilypond[quote,verbatim,relative=1]
2739 \override Score.BarLine #'stencil = ##f
2741 \revert Score.BarLine #'stencil
2745 @node Making objects transparent
2746 @unnumberedsubsubsec Making objects transparent
2748 @cindex transparent, making objects
2750 Every layout object has a transparent property which by default is
2751 set to @code{#f}. If set to @code{#t} the object still occupies
2752 space but is made invisible.
2754 @lilypond[quote,verbatim,relative=2]
2756 \once \override NoteHead #'transparent = ##t
2760 @node Painting objects white
2761 @unnumberedsubsubsec Painting objects white
2763 @cindex objects, coloring
2764 @cindex coloring objects
2766 @cindex printing order
2767 @cindex overwriting objects
2768 @cindex objects, overwriting
2769 @cindex grobs, overwriting
2771 Every layout object has a color property which by default is set
2772 to @code{black}. If this is overridden to @code{white} the object
2773 will be indistinguishable from the white background. However,
2774 if the object crosses other objects the color of the crossing
2775 points will be determined by the order in which they are drawn,
2776 and this may leave a ghostly image of the white object, as shown
2779 @lilypond[quote,verbatim,relative=2]
2780 \override Staff.Clef #'color = #white
2784 This may be avoided by changing the order of printing the objects.
2785 All layout objects have a @code{layer} property which should be set
2786 to an integer. Objects with the lowest value of @code{layer} are
2787 drawn first, then objects with progressively higher values are drawn,
2788 so objects with higher values overwrite objects with lower values.
2789 By default most objects are assigned a @code{layer} value of
2790 @code{1}, although a few objects, including @code{StaffSymbol} and
2791 @code{BarLine}, are assigned a value of @code{0}. The order of
2792 printing objects with the same value of @code{layer} is indeterminate.
2794 In the example above the white clef, with a default @code{layer}
2795 value of @code{1}, is drawn after the staff lines (default
2796 @code{layer} value @code{0}), so overwriting them. To change this,
2797 the @code{Clef} object must be given in a lower value of
2798 @code{layer}, say @w{@code{-1}}, so that it is drawn earlier:
2800 @lilypond[quote,verbatim,relative=2]
2801 \override Staff.Clef #'color = #white
2802 \override Staff.Clef #'layer = #-1
2806 @node Using break-visibility
2807 @unnumberedsubsubsec Using break-visibility
2809 @c TODO Add making other objects breakable
2811 @cindex break-visibility
2813 Most layout objects are printed only once, but some like
2814 bar lines, clefs, time signatures and key signatures, may need
2815 to be printed twice when a line break occurs -- once at the end
2816 of the line and again at the start of the next line. Such
2817 objects are called @emph{breakable}, and have a property, the
2818 @code{break-visibility} property to control their visibility
2819 at the three positions in which they may appear -- at the
2820 start of a line, within a line if they are changed, and at the
2821 end of a line if a change takes place there.
2823 For example, the time signature
2824 by default will be printed at the start of the first line, but
2825 nowhere else unless it changes, when it will be printed at the
2826 point at which the change occurs. If this change occurs at the
2827 end of a line the new time signature will be printed at the start
2828 of the next line and a cautionary time signature will be printed
2829 at the end of the previous line as well.
2831 This behaviour is controlled by the @code{break-visibility}
2832 property, which is explained in
2833 @c Leave this ref on a newline - formats incorrectly otherwise -td
2834 @rlearning{Visibility and color of objects}. This property takes
2835 a vector of three booleans which, in order, determine whether the
2836 object is printed at the end of, within the body of, or at the
2837 beginning of a line. Or to be more precise, before a line break,
2838 where there is no line break, or after a line break.
2840 Alternatively, these eight combinations may be specified
2841 by pre-defined functions, defined in @file{scm/output-lib.scm},
2842 where the last three columns indicate whether the layout objects
2843 will be visible in the positions shown at the head of the columns:
2845 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2846 @headitem Function @tab Vector @tab Before @tab At no @tab After
2847 @headitem form @tab form @tab break @tab break @tab break
2849 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2850 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2851 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2852 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2853 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2854 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2855 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2856 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2859 The default settings of @code{break-visibility} depend on the
2860 layout object. The following table shows all the layout objects
2861 of interest which are affected by @code{break-visibility} and the
2862 default setting of this property:
2864 @multitable @columnfractions .3 .3 .4
2866 @headitem Layout object @tab Usual context @tab Default setting
2868 @c omit Ambitus as it appears not to be affected by break-visibility -td
2869 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2870 @item @code{BarLine} @tab @code{Score} @tab calculated
2871 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2872 @c omit the following item until it can be explained -td
2873 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2874 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2875 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2876 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2877 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2878 @c omit KeyCancellation until it can be explained -td
2879 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2880 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2881 @c omit LeftEdge until it can be explained -td
2882 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2883 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2884 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2885 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2889 The example below shows the use of the vector form to control the
2890 visibility of bar lines:
2892 @lilypond[quote,verbatim,relative=1,ragged-right]
2895 % Remove bar line at the end of the current line
2896 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2902 Although all three components of the vector used to override
2903 @code{break-visibility} must be present, not all of them are
2904 effective with every layout object, and some combinations may
2905 even give errors. The following limitations apply:
2908 @item Bar lines cannot be printed at start of line.
2909 @item A bar number cannot be printed at the start of the first
2910 line unless it is set to be different from 1.
2911 @item Clef -- see below
2912 @item Double percent repeats are either all printed or all
2913 suppressed. Use begin-of line-invisible to print and
2914 all-invisible to suppress.
2915 @item Key signature -- see below
2916 @item OctavateEight -- see below
2919 @node Special considerations
2920 @unnumberedsubsubsec Special considerations
2922 @strong{@emph{Visibility following explicit changes}}
2924 @cindex key signature, visibility following explicit change
2925 @cindex explicitKeySignatureVisibility
2926 @cindex clef, visibility following explicit change
2927 @cindex explicitClefVisibility
2929 The @code{break-visibility} property controls the visibility of
2930 key signatures and changes of clef only at the start of lines,
2931 i.e. after a break. It has no effect on the visibility of the
2932 key signature or clef following an explicit key change or an
2933 explicit clef change within or at the end of a line. In the
2934 following example the key signature following the explicit change
2935 to B-flat major is still visible, even though @code{all-invisible}
2938 @lilypond[quote,verbatim,relative=1,ragged-right]
2941 % Try to remove all key signatures
2942 \override Staff.KeySignature #'break-visibility = #all-invisible
2950 The visibility of such explicit key signature and clef changes is
2951 controlled by the @code{explicitKeySignatureVisibility} and
2952 @code{explicitClefVisibility} properties. These are the equivalent
2953 of the @code{break-visibility} property and both take a vector of
2954 three booleans or the predefined functions listed above, exactly like
2955 @code{break-visibility}. Both are properties of the Staff context,
2956 not the layout objects themselves, and so they are set using the
2957 @code{\set} command. Both are set by default to @code{all-visible}.
2958 These properties control only the visibility of key signatures and
2959 clefs resulting from explicit changes and do not affect key
2960 signatures and clefs at the beginning of lines;
2961 @code{break-visibility} must still be overridden in the appropriate
2962 object to remove these.
2964 @lilypond[quote,verbatim,relative=1,ragged-right]
2967 \set Staff.explicitKeySignatureVisibility = #all-invisible
2968 \override Staff.KeySignature #'break-visibility = #all-invisible
2975 @strong{@emph{Visibility of cautionary accidentals}}
2977 To remove the cautionary accidentals printed at an explicit key
2978 change, set the Staff context property @code{printKeyCancellation}
2981 @lilypond[quote,verbatim,relative=1,ragged-right]
2984 \set Staff.explicitKeySignatureVisibility = #all-invisible
2985 \set Staff.printKeyCancellation = ##f
2986 \override Staff.KeySignature #'break-visibility = #all-invisible
2993 With these overrides only the accidentals before the notes remain
2994 to indicate the change of key.
2996 @c TODO Add visibility of cautionary accidentals before notes
2998 @strong{@emph{Automatic bars}}
3000 @cindex automaticBars
3001 @cindex bar lines, suppressing
3003 As a special case, the printing of bar lines can also be turned off
3004 by setting the @code{automaticBars} property in the Score context.
3005 If set to @code{#f}, bar lines will not be printed automatically;
3006 they must be explicitly created with a @code{\bar} command. Unlike
3007 the @code{\cadenzaOn} predefined command, measures are still counted.
3008 Bar generation will resume according to that count if this property
3009 is later set to @code{#t}. When set to @code{#f}, line breaks can
3010 occur only at explicit @code{\bar} commands.
3014 @strong{@emph{Octavated clefs}}
3016 @cindex octavated clefs, visibility of
3017 @cindex visibility of octavated clefs
3018 @cindex clefs, visibility of octavation
3020 The small octavation symbol on octavated clefs is produced by the
3021 @code{OctavateEight} layout object. Its visibility is automatically
3022 inherited from the @code{Clef} object, so it is not necessary to apply
3023 any required @code{break-visibility} overrides to the @code{OctavateEight}
3024 layout objects to suppress octavation symbols for invisible clefs.
3026 For explicit clef changes, the @code{explicitClefVisibility}
3027 property controls both the clef symbol and any octavation symbol
3033 @rlearning{Visibility and color of objects}
3037 @subsection Line styles
3039 Some performance indications, e.g., @i{rallentando} and
3040 @i{accelerando} and @i{trills} are written as text and are
3041 extended over many measures with lines, sometimes dotted or wavy.
3043 These all use the same routines as the glissando for drawing the
3044 texts and the lines, and tuning their behavior is therefore also
3045 done in the same way. It is done with a spanner, and the routine
3046 responsible for drawing the spanners is
3047 @code{ly:line-interface::print}. This routine determines the
3048 exact location of the two @i{span points} and draws a line
3049 between them, in the style requested.
3051 Here is an example showing the different line styles available,
3052 and how to tune them.
3054 @lilypond[relative=2,ragged-right,verbatim,quote]
3056 \once \override Glissando #'style = #'dashed-line
3058 \override Glissando #'style = #'dotted-line
3060 \override Glissando #'style = #'zigzag
3062 \override Glissando #'style = #'trill
3066 The locations of the end-points of the spanner are computed
3067 on-the-fly for every graphic object, but it is possible to
3071 @lilypond[relative=2,ragged-right,verbatim,quote]
3073 \once \override Glissando #'(bound-details right Y) = #-2
3077 The value for @code{Y} is set to @w{@code{-2}} for the right end
3078 point. The left side may be similarly adjusted by specifying
3079 @code{left} instead of @code{right}.
3081 If @code{Y} is not set, the value is computed from the vertical
3082 position of the left and right attachment points of the spanner.
3084 Other adjustments of spanners are possible, for details, see
3087 @node Rotating objects
3088 @subsection Rotating objects
3090 Both layout objects and elements of markup text can be rotated by
3091 any angle about any point, but the method of doing so differs.
3094 * Rotating layout objects::
3098 @node Rotating layout objects
3099 @unnumberedsubsubsec Rotating layout objects
3101 @cindex rotating objects
3102 @cindex objects, rotating
3104 All layout objects which support the @code{grob-interface} can be
3105 rotated by setting their @code{rotation} property. This takes a
3106 list of three items: the angle of rotation counter-clockwise,
3107 and the x and y coordinates of the point relative to the object's
3108 reference point about which the rotation is to be performed. The
3109 angle of rotation is specified in degrees and the coordinates in
3112 The angle of rotation and the coordinates of the rotation point must
3113 be determined by trial and error.
3115 @cindex hairpins, angled
3116 @cindex angled hairpins
3118 There are only a few situations where the rotation of layout
3119 objects is useful; the following example shows one situation where
3122 @lilypond[quote,verbatim,relative=1]
3124 \override Hairpin #'rotation = #'(20 -1 0)
3128 @node Rotating markup
3129 @unnumberedsubsubsec Rotating markup
3131 All markup text can be rotated to lie at any angle by prefixing it
3132 with the @code{\rotate} command. The command takes two arguments:
3133 the angle of rotation in degrees counter-clockwise and the text to
3134 be rotated. The extents of the text are not rotated: they take
3135 their values from the extremes of the x and y coordinates of the
3136 rotated text. In the following example the
3137 @code{outside-staff-priority} property for text is set to @code{#f}
3138 to disable the automatic collision avoidance, which would push some
3139 of the text too high.
3141 @lilypond[quote,verbatim,relative=1]
3142 \override TextScript #'outside-staff-priority = ##f
3143 g4^\markup { \rotate #30 "a G" }
3144 b^\markup { \rotate #30 "a B" }
3145 des^\markup { \rotate #30 "a D-Flat" }
3146 fis^\markup { \rotate #30 "an F-Sharp" }
3149 @node Advanced tweaks
3150 @section Advanced tweaks
3152 This section discusses various approaches to fine tuning the
3153 appearance of the printed score.
3156 * Aligning objects::
3157 * Vertical grouping of grobs::
3158 * Modifying stencils::
3159 * Modifying shapes::
3165 @rlearning{Tweaking output},
3166 @rlearning{Other sources of information}.
3169 @ref{Explaining the Internals Reference},
3170 @ref{Modifying properties}.
3173 @file{scm/define-grobs.scm}.
3176 @rlsr{Tweaks and overrides}.
3179 @rextend{Interfaces for programmers}.
3181 Internals Reference:
3182 @rinternals{All layout objects}.
3185 @node Aligning objects
3186 @subsection Aligning objects
3188 Graphical objects which support the @code{self-alignment-interface}
3189 and/or the @code{side-position-interface} can be aligned to a previously
3190 placed object in a variety of ways. For a list of these objects, see
3191 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
3193 All graphical objects have a reference point, a horizontal extent and a
3194 vertical extent. The horizontal extent is a pair of numbers
3195 giving the displacements from the reference point of the left and
3196 right edges, displacements to the left being negative. The vertical
3197 extent is a pair of numbers giving the displacement from the reference
3198 point to the bottom and top edges, displacements down being negative.
3200 An object's position on a staff is given by the values of the
3201 @code{X-offset} and @code{Y-offset} properties. The value of
3202 @code{X-offset} gives the displacement from the X coordinate of
3203 the reference point of the parent object, and the value of
3204 @code{Y-offset} gives the displacement from the center line of the
3205 staff. The values of @code{X-offset} and @code{Y-offset} may
3206 be set directly or may be set to be calculated by procedures in order
3207 to achieve alignment with the parent object.
3209 @warning{Many objects have special positioning considerations which
3210 cause any setting of @code{X-offset} or @code{Y-offset} to be
3211 ignored or modified, even though the object supports the
3212 @code{self-alignment-interface}. Overriding the @code{X-offset}
3213 or @code{Y-offset} properties to a fixed value causes the respective
3214 @code{self-alignment} property to be disregarded.}
3216 For example, an accidental can be repositioned vertically by setting
3217 @code{Y-offset} but any changes to @code{X-offset} have no effect.
3219 Rehearsal marks may be aligned with breakable objects such as bar
3220 lines, clef symbols, time signature symbols and key signatures. There
3221 are special properties to be found in the @code{break-aligned-interface}
3222 for positioning rehearsal marks on such objects.
3225 @ref{Using the break-alignable-interface},
3226 @rextend{Callback functions}.
3229 * Setting X-offset and Y-offset directly::
3230 * Using the side-position-interface::
3231 * Using the self-alignment-interface::
3232 * Using the break-alignable-interface::
3235 @node Setting X-offset and Y-offset directly
3236 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
3238 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
3239 properties of many objects. The following example shows three
3240 notes with the default fingering position and the positions with @code{X-offset}
3241 and @code{Y-offset} modified.
3243 @lilypond[verbatim,quote,relative=2]
3246 -\tweak #'X-offset #0
3247 -\tweak #'Y-offset #0
3250 -\tweak #'X-offset #-1
3251 -\tweak #'Y-offset #1
3257 @node Using the side-position-interface
3258 @unnumberedsubsubsec Using the @code{side-position-interface}
3260 An object which supports the @code{side-position-interface} can be
3261 placed next to its parent object so that
3262 the specified edges of the two objects touch. The object may be
3263 placed above, below, to the right or to the left of the parent.
3264 The parent cannot be specified; it is determined by the order of
3265 elements in the input stream. Most objects have the associated
3266 note head as their parent.
3268 The values of the @code{side-axis} and @code{direction} properties
3269 determine where the object is to be placed, as follows:
3271 @c TODO add an example of each to the table
3273 @multitable @columnfractions .3 .3 .3
3274 @headitem @code{side-axis} @tab @code{direction} @tab
3275 @headitem property @tab property @tab Placement
3277 @item @code{0} @tab @code{-1} @tab left
3278 @item @code{0} @tab @code{1} @tab right
3279 @item @code{1} @tab @code{-1} @tab below
3280 @item @code{1} @tab @code{1} @tab above
3284 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
3285 the procedure @code{ly:side-position-interface::x-aligned-side}.
3286 This procedure will return the correct value of @code{X-offset} to
3287 place the object to the left or right side of the parent according
3288 to value of @code{direction}.
3290 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3291 the procedure @code{ly:side-position-interface::y-aligned-side}.
3292 This procedure will return the correct value of @code{Y-offset} to
3293 place the object to the top or bottom of the parent according
3294 to value of @code{direction}.
3296 @c TODO Add examples
3298 @node Using the self-alignment-interface
3299 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3301 @emph{Self-aligning objects horizontally}
3303 The horizontal alignment of an object which supports the
3304 @code{self-alignment-interface} is controlled by the value of
3305 the @code{self-alignment-X} property, provided the object's
3306 @code{X-offset} property is set to
3307 @code{ly:self-alignment-interface::x-aligned-on-self}.
3308 @code{self-alignment-X} may be given any
3309 real value, in units of half the total X extent of the
3310 object. Negative values move the object to the right, positive
3311 to the left. A value of @code{0} centers the object on the
3312 reference point of its parent, a value of @w{@code{-1}} aligns the
3313 left edge of the object on the reference point of its parent,
3314 and a value of @code{1} aligns the right edge of the object on the
3315 reference point of its parent. The symbols @code{LEFT},
3316 @code{CENTER}, and @code{RIGHT} may be used instead of the values
3317 @w{@code{-1}}, @code{0}, and @code{1}, respectively.
3319 Normally the @code{\override} command would be used to modify the
3320 value of @code{self-alignment-X}, but the @code{\tweak} command
3321 can be used to separately align several annotations on a single
3324 @lilypond[quote,verbatim,relative=1]
3326 -\tweak #'self-alignment-X #-1
3328 -\tweak #'self-alignment-X #0
3330 -\tweak #'self-alignment-X #RIGHT
3332 -\tweak #'self-alignment-X #-2.5
3333 ^"aligned further to the right"
3336 @emph{Self-aligning objects vertically}
3338 Objects may be aligned vertically in an analogous way to aligning
3339 them horizontally if the @code{Y-offset} property is set to
3340 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3341 other mechanisms are often involved in vertical alignment: the
3342 value of @code{Y-offset} is just one variable taken into account.
3343 This may make adjusting the value of some objects tricky.
3344 The units are just half the vertical extent of the object, which
3345 is usually quite small, so quite large numbers may be required.
3346 A value of @w{@code{-1}} aligns the lower edge of the object with
3347 the reference point of the parent object, a value of @code{0}
3348 aligns the center of the object with the reference point of the
3349 parent, and a value of @code{1} aligns the top edge of the object
3350 with the reference point of the parent. The symbols @code{DOWN},
3351 @code{CENTER}, and @code{UP} may be substituted for @w{@code{-1}},
3352 @code{0}, and @code{1}, respectively.
3354 @emph{Self-aligning objects in both directions}
3356 By setting both @code{X-offset} and @code{Y-offset}, an object may
3357 be aligned in both directions simultaneously.
3359 The following example shows how to adjust a fingering mark so
3360 that it nestles close to the note head.
3362 @lilypond[quote,verbatim,relative=2]
3364 -\tweak #'self-alignment-X #0.5 % move horizontally left
3365 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
3366 -\tweak #'self-alignment-Y #-1 % move vertically up
3371 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3373 @c Cannot document as they do not seem to operate consistently on all objects -td
3374 @c TODO investigate further
3376 The @code{aligned-on-parent} procedures are used in the same way
3377 as the @code{aligned-on-self} procedures, they difference being
3378 that they permit an object to be aligned with the @emph{edges} of
3379 the parent rather than the parent's reference point. The following
3380 example shows the difference:
3384 @lilypond[verbatim,quote]
3390 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3392 @c Cannot document as they do not seem to operate consistently on all objects -td
3393 @c TODO investigate further
3397 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3399 @node Using the break-alignable-interface
3400 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3402 @cindex align to objects
3403 @cindex break-align-symbols
3405 Rehearsal marks and bar numbers may be aligned with notation
3406 objects other than bar lines. These objects include @code{ambitus},
3407 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3408 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3409 @code{time-signature}.
3411 By default, rehearsal marks and bar numbers will be horizontally
3412 centered above the object:
3414 @lilypond[verbatim,quote,relative=1]
3415 % The rehearsal mark will be centered above the Clef
3416 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
3421 % The rehearsal mark will be centered above the Time Signature
3422 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
3428 % The rehearsal mark will be centered above the Breath Mark
3429 \override Score.RehearsalMark #'break-align-symbols = #'(breathing-sign)
3438 A list of possible target alignment objects may be specified. If
3439 some of the objects are invisible at that point due to the setting
3440 of @code{break-visibility} or the explicit visibility settings for
3441 keys and clefs, the rehearsal mark or bar number is aligned to the
3442 first object in the list which is visible. If no objects in the
3443 list are visible the object is aligned to the bar line. If the bar
3444 line is invisible the object is aligned to the place where the bar
3447 @lilypond[verbatim,quote,relative=1]
3448 % The rehearsal mark will be centered above the Key Signature
3449 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3454 % The rehearsal mark will be centered above the Clef
3455 \set Staff.explicitKeySignatureVisibility = #all-invisible
3456 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3461 % The rehearsal mark will be centered above the Bar Line
3462 \set Staff.explicitKeySignatureVisibility = #all-invisible
3463 \set Staff.explicitClefVisibility = #all-invisible
3464 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3471 The alignment of the rehearsal mark relative to the notation object
3472 can be changed, as shown in the following example. In a score with
3473 multiple staves, this setting should be done for all the staves.
3475 @lilypond[verbatim,quote,relative=1]
3476 % The RehearsalMark will be centered above the Key Signature
3477 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3483 % The RehearsalMark will be aligned with the left edge of the Key Signature
3484 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3488 % The RehearsalMark will be aligned with the right edge of the Key Signature
3489 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3495 The rehearsal mark can also be offset to the right or left of the left
3496 edge by an arbitrary amount. The units are staff-spaces:
3498 @lilypond[verbatim,quote,relative=1]
3499 % The RehearsalMark will be aligned with the left edge of the Key Signature
3500 % and then shifted right by 3.5 staff-spaces
3501 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3502 \once \override Score.KeySignature #'break-align-anchor = #3.5
3506 % The RehearsalMark will be aligned with the left edge of the Key Signature
3507 % and then shifted left by 2 staff-spaces
3508 \once \override Score.KeySignature #'break-align-anchor = #-2
3515 @node Vertical grouping of grobs
3516 @subsection Vertical grouping of grobs
3518 @c TODO Expand this section
3520 The VerticalAlignment and VerticalAxisGroup grobs work together.
3521 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3522 etc. VerticalAlignment then vertically aligns the different grobs
3523 grouped together by VerticalAxisGroup. There is usually only one
3524 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3528 @node Modifying stencils
3529 @subsection Modifying stencils
3531 All layout objects have a @code{stencil} property which is part of
3532 the @code{grob-interface}. By default, this property is usually
3533 set to a function specific to the object that is tailor-made to
3534 render the symbol which represents it in the output. For example,
3535 the standard setting for the @code{stencil} property of the
3536 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3538 The standard symbol for any object can be replaced by modifying the
3539 @code{stencil} property to reference a different, specially-written,
3540 procedure. This requires a high level of knowledge of the internal
3541 workings of LilyPond, but there is an easier way which can often
3542 produce adequate results.
3544 This is to set the @code{stencil} property to the procedure which
3545 prints text -- @code{ly:text-interface::print} -- and to add a
3546 @code{text} property to the object which is set to contain the
3547 markup text which produces the required symbol. Due to the
3548 flexibility of markup, much can be achieved -- see in particular
3549 @ref{Graphic notation inside markup}.
3551 The following example demonstrates this by changing the note head
3552 symbol to a cross within a circle.
3554 @lilypond[verbatim,quote]
3556 \once \override NoteHead #'stencil = #ly:text-interface::print
3557 \once \override NoteHead #'text = \markup {
3559 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3560 \musicglyph #"noteheads.s2cross"
3568 Any of the glyphs in the feta Font can be supplied to the
3569 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3571 @c TODO Add inserting eps files or ref to later
3573 @c TODO Add inserting Postscript or ref to later
3578 @ref{Graphic notation inside markup},
3579 @ref{Formatting text},
3580 @ref{Text markup commands},
3581 @ref{The Feta font}.
3584 @node Modifying shapes
3585 @subsection Modifying shapes
3588 * Modifying ties and slurs::
3591 @node Modifying ties and slurs
3592 @unnumberedsubsubsec Modifying ties and slurs
3594 @cindex slurs, modifying
3595 @cindex ties, modifying
3596 @cindex Bézier curves, control points
3597 @cindex control points, Bézier curves
3599 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3600 curves. If the shape of the tie or slur which is calculated
3601 automatically is not optimum, the shape may be modified manually by
3602 explicitly specifying the four control points required to define
3603 a third-order Bézier curve.
3605 Third-order or cubic Bézier curves are defined by four control
3606 points. The first and fourth control points are precisely the
3607 starting and ending points of the curve. The intermediate two
3608 control points define the shape. Animations showing how the curve
3609 is drawn can be found on the web, but the following description
3610 may be helpful. The curve starts from the first control point
3611 heading directly towards the second, gradually bending over to
3612 head towards the third and continuing to bend over to head towards
3613 the fourth, arriving there travelling directly from the third
3614 control point. The curve is entirely contained in the
3615 quadrilateral defined by the four control points.
3617 Here is an example of a case where the tie is not optimum, and
3618 where @code{\tieDown} would not help.
3620 @lilypond[verbatim,quote,relative=1]
3624 { r4 <g c,> <g c,> <g c,> }
3628 One way of improving this tie is to manually modify its control
3631 The coordinates of the Bézier control points are specified in units
3632 of staff-spaces. The X@tie{}coordinate is relative to the reference
3633 point of the note to which the tie or slur is attached, and the
3634 Y@tie{}coordinate is relative to the staff center line. The
3635 coordinates are entered as a list of four pairs of decimal numbers
3636 (reals). One approach is to estimate the coordinates of the two
3637 end points, and then guess the two intermediate points. The optimum
3638 values are then found by trial and error.
3640 It is useful to remember that a symmetric curve requires symmetric
3641 control points, and that Bézier curves have the useful property that
3642 transformations of the curve such as translation, rotation and
3643 scaling can be achieved by applying the same transformation to the
3644 curve's control points.
3646 For the example above the following override gives a satisfactory
3647 tie. Note the placement -- it has to be immediately before the note
3648 to which the start of the tie (or slur) is attached.
3650 @lilypond[verbatim,quote,relative=1]
3654 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3658 { r4 <g c,> <g c,> <g c,> }
3663 It is not possible to modify shapes of ties or slurs by changing
3664 the @code{control-points} property if there are multiple ties or slurs
3665 at the same musical moment -- the @code{\tweak} command will also not
3666 work in this case. However, the @code{tie-configuration} property of
3667 @code{TieColumn} can be overridden to set start line and direction as
3671 Internals Reference:
3672 @rinternals{TieColumn}.
3675 @node Using music functions
3676 @section Using music functions
3678 @c TODO -- add @seealso, etc. to these subsections
3680 Where tweaks need to be reused with different music expressions,
3681 it is often convenient to make the tweak part of a @emph{music
3682 function}. In this section, we discuss only @emph{substitution}
3683 functions, where the object is to substitute a variable into a
3684 piece of LilyPond input code. Other more complex functions are
3685 described in @rextend{Music functions}.
3688 * Substitution function syntax::
3689 * Substitution function examples::
3692 @node Substitution function syntax
3693 @subsection Substitution function syntax
3695 Making a function that substitutes a variable into LilyPond
3696 code is easy. The general form of these functions is
3700 #(define-music-function
3701 (parser location @var{arg1} @var{arg2} @dots{})
3702 (@var{type1?} @var{type2?} @dots{})
3704 @var{@dots{}music@dots{}}
3711 @multitable @columnfractions .33 .66
3712 @item @code{@var{argN}}
3713 @tab @var{n}th argument
3715 @item @code{@var{typeN?}}
3716 @tab a scheme @emph{type predicate} for which @code{@var{argN}}
3717 must return @code{#t}.
3719 @item @code{@var{@dots{}music@dots{}}}
3720 @tab normal LilyPond input, using @code{$} to reference arguments
3725 The @code{parser} and @code{location} arguments are mandatory, and
3726 are used in some advanced situations as described in the
3727 @q{Extending} manual (see @rextend{Music functions}). For
3728 substitution functions, just be sure to include them.
3730 The list of type predicates is also required. Some of the most
3731 common type predicates used in music functions are:
3735 cheap-list? @emph{(use instead of }@q{list?}@emph{ for faster processing)}
3745 For a list of available type predicates, see
3746 @ref{Predefined type predicates}. User-defined type predicates
3753 @ref{Predefined type predicates}.
3756 @rextend{Music functions}.
3759 @file{lily/music-scheme.cc},
3761 @file{scm/lily.scm}.
3764 @node Substitution function examples
3765 @subsection Substitution function examples
3767 This section introduces some substitution function examples.
3768 These are not intended to be exhaustive, but rather to demonstrate
3769 some of the possibilities of simple substitution functions.
3771 In the first example, a function is defined that simplifies
3772 setting the padding of a TextScript:
3774 @lilypond[quote,verbatim,ragged-right]
3776 #(define-music-function
3777 (parser location padding)
3780 \once \override TextScript #'padding = $padding
3784 c4^"piu mosso" b a b
3786 c4^"piu mosso" d e f
3788 c4^"piu mosso" fis a g
3792 In addition to numbers, we can use music expressions such
3793 as notes for arguments to music functions:
3795 @c TODO: use a better example (the music argument is redundant).
3797 @lilypond[quote,verbatim,ragged-right]
3799 #(define-music-function
3800 (parser location note)
3803 \once \override Voice.NoteHead #'stencil =
3804 #ly:text-interface::print
3805 \once \override Voice.NoteHead #'text =
3806 \markup \musicglyph #"custodes.mensural.u0"
3807 \once \override Voice.Stem #'stencil = ##f
3811 \relative c' { c4 d e f \custosNote g }
3814 Substitution functions with multiple arguments can be defined:
3816 @lilypond[quote,verbatim,ragged-right]
3818 #(define-music-function
3819 (parser location padding tempotext)
3822 \once \override Score.MetronomeMark #'padding = $padding
3823 \tempo \markup { \bold $tempotext }
3827 \tempo \markup { "Low tempo" }
3829 \tempoPadded #4.0 #"High tempo"
3834 @c TODO: add appropriate @@ref's here.