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13 @node Changing defaults
14 @chapter Changing defaults
16 The purpose of LilyPond's design is to provide the finest quality
17 output by default. Nevertheless, it may happen that you need to
18 change this default layout. The layout is controlled through a large
19 number of @q{knobs and switches} collectively called @q{properties}.
20 A tutorial introduction to accessing and modifying these properties
21 can be found in the Learning Manual, see @rlearning{Tweaking output}.
22 This should be read first. This chapter covers similar ground, but
23 in a style more appropriate to a reference manual.
25 @cindex Internals Reference
27 The definitive description of the controls available for tuning can
28 be found in a separate document: @rinternalsnamed{Top,the Internals
29 Reference}. That manual lists all the variables, functions and
30 options available in LilyPond. It is written as a HTML document,
32 @c leave the @uref as one long line.
33 @uref{http://@/lilypond@/.org/@/doc/@/stable/@/Documentation/@/internals/,on@/-line},
34 and is also included with the LilyPond documentation package.
36 Internally, LilyPond uses Scheme (a LISP dialect) to provide
37 infrastructure. Overriding layout decisions in effect accesses the
38 program internals, which requires Scheme input. Scheme elements are
39 introduced in a @file{.ly} file with the hash
40 mark@tie{}@code{#}.@footnote{@rextend{Scheme tutorial}, contains a
41 short tutorial on entering numbers, lists, strings, and symbols in
46 * Interpretation contexts::
47 * Explaining the Internals Reference::
48 * Modifying properties::
49 * Useful concepts and properties::
51 * Using music functions::
55 @node Interpretation contexts
56 @section Interpretation contexts
58 This section describes what contexts are, and how to modify them.
61 * Contexts explained::
63 * Keeping contexts alive::
64 * Modifying context plug-ins::
65 * Changing context default settings::
66 * Defining new contexts::
67 * Context layout order::
72 @rlearning{Contexts and engravers}.
75 @file{ly/engraver-init.ly},
76 @file{ly/performer-init.ly}.
79 @rlsr{Contexts and engravers}.
82 @rinternals{Contexts},
83 @rinternals{Engravers and Performers}.
86 @node Contexts explained
87 @subsection Contexts explained
90 @c TODO Rethink and rewrite
92 >> > > - list of contexts: my *danger unmaintainable*
93 >> > > alarm just went off. I'm
95 I knew it would... And leaving out some of them is perfectly fine
97 I do think that a list like this, with the main contexts and a
99 description of what they do (perhaps also with a note about what
101 behavior is associated with each of them, but this may be
103 should be there, and then we could simply list the remaining ones
105 further explanation and with links to the IR.
108 @c TODO Improve layout, order and consistency of wording -td
110 @c TODO Add introduction which explains contexts in generality -td
112 @c TODO Describe propagation of property values -td
114 Contexts are arranged hierarchically:
117 * Score - the master of all contexts::
118 * Top-level contexts - staff containers::
119 * Intermediate-level contexts - staves::
120 * Bottom-level contexts - voices::
123 @node Score - the master of all contexts
124 @unnumberedsubsubsec Score - the master of all contexts
126 This is the top level notation context. No other context can
127 contain a Score context. By default the Score context handles
128 the administration of time signatures and makes sure that items
129 such as clefs, time signatures, and key-signatures are aligned
132 A Score context is instantiated implicitly when a
133 @code{\score @{@dots{}@}} or @code{\layout @{@dots{}@}} block is
136 @node Top-level contexts - staff containers
137 @unnumberedsubsubsec Top-level contexts - staff containers
139 @strong{@emph{StaffGroup}}
141 Groups staves while adding a bracket on the left side, grouping
142 the staves together. The bar lines of the contained staves are
143 connected vertically. @code{StaffGroup} only consists of a collection
144 of staves, with a bracket in front and spanning bar lines.
146 @strong{@emph{ChoirStaff}}
148 Identical to @code{StaffGroup} except that the bar lines of the
149 contained staves are not connected vertically.
151 @strong{@emph{GrandStaff}}
153 A group of staves, with a brace on the left side, grouping the
154 staves together. The bar lines of the contained staves are
155 connected vertically.
157 @strong{@emph{PianoStaff}}
159 Just like @code{GrandStaff}, but with support for instrument names
160 to the left of each system.
162 @node Intermediate-level contexts - staves
163 @unnumberedsubsubsec Intermediate-level contexts - staves
165 @strong{@emph{Staff}}
167 Handles clefs, bar lines, keys, accidentals. It can contain
168 @code{Voice} contexts.
170 @strong{@emph{RhythmicStaff}}
172 Like @code{Staff} but for printing rhythms. Pitches are ignored;
173 the notes are printed on one line.
175 @strong{@emph{TabStaff}}
177 Context for generating tablature. By default lays the music
178 expression out as a guitar tablature, printed on six lines.
180 @strong{@emph{DrumStaff}}
182 Handles typesetting for percussion. Can contain @code{DrumVoice}
184 @strong{@emph{VaticanaStaff}}
186 Same as @code{Staff}, except that it is designed for typesetting
187 a piece in gregorian style.
189 @strong{@emph{MensuralStaff}}
191 Same as @code{Staff}, except that it is designed for typesetting
192 a piece in mensural style.
194 @node Bottom-level contexts - voices
195 @unnumberedsubsubsec Bottom-level contexts - voices
197 Voice-level contexts initialise certain properties and start
198 appropriate engravers. Being bottom-level contexts, they cannot
199 contain other contexts.
201 @strong{@emph{Voice}}
203 Corresponds to a voice on a staff. This context handles the
204 conversion of dynamic signs, stems, beams, super- and sub-scripts,
205 slurs, ties, and rests. You have to instantiate this explicitly
206 if you require multiple voices on the same staff.
208 @strong{@emph{VaticanaVoice}}
210 Same as @code{Voice}, except that it is designed for typesetting
211 a piece in gregorian style.
213 @strong{@emph{MensuralVoice}}
215 Same as @code{Voice}, with modifications for typesetting a piece in
218 @strong{@emph{Lyrics}}
220 Corresponds to a voice with lyrics. Handles the printing of a
221 single line of lyrics.
223 @strong{@emph{DrumVoice}}
225 The voice context used in a percussion staff.
227 @strong{@emph{FiguredBass}}
229 The context in which @code{BassFigure} objects are created from
230 input entered in @code{\figuremode} mode.
232 @strong{@emph{TabVoice}}
234 The voice context used within a @code{TabStaff} context. Usually
235 left to be created implicitly.
237 @strong{@emph{CueVoice}}
239 A voice context used to render notes of a reduced size, intended
240 primarily for adding cue notes to a staff, see @ref{Formatting
241 cue notes}. Usually left to be created implicitly.
243 @strong{@emph{ChordNames}}
245 Typesets chord names.
250 Then the following, which I don't know what to do with:
252 * GregorianTranscriptionVoice
253 * GregorianTranscriptionStaff
256 Engraves fretboards from chords. Not easy... Not
258 There is now some documentation on FretBoards in the NR, under
259 instrument-specific notation -- cds.
264 Hard coded entry point for LilyPond. Cannot be tuned.
266 Silently discards all musical information given to this
271 @node Creating contexts
272 @subsection Creating contexts
274 @c TODO more complete descriptions rather than learning style
276 For scores with only one voice and one staff, contexts are
277 created automatically. For more complex scores, it is necessary to
278 create them by hand. There are three commands that do this.
283 The easiest command is @code{\new}, and it also the quickest to type.
284 It is prepended to a music expression, for example
288 @cindex Context, creating
291 \new @var{type} @var{music expression}
295 where @var{type} is a context name (like @code{Staff} or
296 @code{Voice}). This command creates a new context, and starts
297 interpreting the @var{music expression} with that.
299 A practical application of @code{\new} is a score with many
300 staves. Each part that should be on its own staff, is preceded with
303 @lilypond[quote,verbatim,relative=2,ragged-right]
310 The @code{\new} command may also give a name to the context,
313 \new @var{type} = @var{id} @var{music}
315 However, this user specified name is only used if there is no other
316 context already earlier with the same name.
322 Like @code{\new}, the @code{\context} command also directs a music
323 expression to a context object, but gives the context an explicit name. The
327 \context @var{type} = @var{id} @var{music}
330 This form will search for an existing context of type @var{type}
331 called @var{id}. If that context does not exist yet, a new
332 context with the specified name is created. This is useful if
333 the context is referred to later on. For example, when
334 setting lyrics the melody is in a named context
337 \context Voice = "@b{tenor}" @var{music}
341 so the texts can be properly aligned to its notes,
344 \new Lyrics \lyricsto "@b{tenor}" @var{lyrics}
349 Another possible use of named contexts is funneling two different
350 music expressions into one context. In the following example,
351 articulations and notes are entered separately,
355 arts = @{ s4-. s4-> @}
358 They are combined by sending both to the same @code{Voice} context,
362 \new Staff \context Voice = "A" \music
363 \context Voice = "A" \arts
366 @lilypond[quote,ragged-right]
370 \new Staff \context Voice = "A" \music
371 \context Voice = "A" \arts
375 With this mechanism, it is possible to define an Urtext (original
376 edition), with the option to put several distinct articulations on the
379 @cindex creating contexts
382 The third command for creating contexts is
384 \context @var{type} @var{music}
389 This is similar to @code{\context} with @code{= @var{id}}, but matches
390 any context of type @var{type}, regardless of its given name.
392 This variant is used with music expressions that can be interpreted at
393 several levels. For example, the @code{\applyOutput} command (see
394 @rextend{Running a function on all layout objects}). Without an explicit
395 @code{\context}, it is usually applied to @code{Voice}
398 \applyOutput #'@var{context} #@var{function} % apply to Voice
401 To have it interpreted at the @code{Score} or @code{Staff} level use
405 \applyOutput #'Score #@var{function}
406 \applyOutput #'Staff #@var{function}
411 @node Keeping contexts alive
412 @subsection Keeping contexts alive
414 @cindex contexts, keeping alive
415 @cindex contexts, lifetime
417 Contexts are usually terminated at the first musical moment in
418 which they have nothing to do. So @code{Voice} contexts die as
419 soon as they contain no events; @code{Staff} contexts die as soon
420 as all the @code{Voice} contexts within them contain no events; etc.
421 This can cause difficulties if earlier contexts which have died
422 have to be referenced, for example, when changing staves with
423 @code{\change} commands, associating lyrics with a voice with
424 @code{\lyricsto} commands, or when adding further musical events to
427 There is an exception to this general rule: just one of the
428 @code{Voice} contexts in a @code{Staff} context or in a
429 @code{<<...>>} construct will always persist to the end of the
430 enclosing @code{Staff} context or @code{<<...>>} construct, even
431 though there may be periods when it has nothing to do. The context
432 to persist in this way will be the first one encountered in the
433 first enclosed @code{@{...@}} construct, ignoring any in enclosed
434 @code{<<...>>} constructs.
436 Any context can be kept alive by ensuring it has something to do at
437 every musical moment. @code{Staff} contexts are kept alive by
438 ensuring one of their voices is kept alive. One way of doing this
439 is to add spacer rests to a voice in parallel with the real music.
440 These need to be added to every @code{Voice} context which needs to
441 be kept alive. If several voices are to be used sporadically it is
442 safest to keep them all alive rather than attempting to rely on the
443 exceptions mentioned above.
445 In the following example, both voice A and voice B are kept alive
446 in this way for the duration of the piece:
448 @lilypond[quote,verbatim]
449 musicA = \relative c'' { d4 d d d }
450 musicB = \relative c'' { g4 g g g }
453 \new Voice = "A" { s1*5 } % Keep Voice "A" alive for 5 bars
454 \new Voice = "B" { s1*5 } % Keep Voice "B" alive for 5 bars
459 \context Voice = "A" {
463 \context Voice = "B" {
467 \context Voice = "A" { \musicA }
468 \context Voice = "B" { \musicB }
469 \context Voice = "A" { \musicA }
480 @cindex lyrics, aligning with sporadic melody
482 The following example shows how a sporadic melody line with lyrics
483 might be written using this approach. In a real situation the
484 melody and accompaniment would consist of several different
487 @lilypond[quote,verbatim]
488 melody = \relative c'' { a4 a a a }
489 accompaniment = \relative c' { d4 d d d }
490 words = \lyricmode { These words fol -- low the mel -- o -- dy }
493 \new Staff = "music" {
495 \new Voice = "melody" {
497 s1*4 % Keep Voice "melody" alive for 4 bars
500 \new Voice = "accompaniment" {
505 \context Voice = "melody" { \melody }
506 \context Voice = "accompaniment" { \accompaniment }
508 \context Voice = "accompaniment" { \accompaniment }
510 \context Voice = "melody" { \melody }
511 \context Voice = "accompaniment" { \accompaniment }
516 \new Lyrics \with { alignAboveContext = #"music" }
517 \lyricsto "melody" { \words }
522 An alternative way, which may be better in many circumstances, is
523 to keep the melody line alive by simply including spacer notes to
524 line it up correctly with the accompaniment:
526 @lilypond[quote,verbatim]
527 melody = \relative c'' {
533 accompaniment = \relative c' {
539 words = \lyricmode { These words fol -- low the mel -- o -- dy }
543 \new Staff = "music" {
545 \new Voice = "melody" {
549 \new Voice = "accompaniment" {
555 \new Lyrics \with { alignAboveContext = #"music" }
556 \lyricsto "melody" { \words }
562 @node Modifying context plug-ins
563 @subsection Modifying context plug-ins
565 @c TODO Should this be Modifying engravers or Modifying contexts?
567 Notation contexts (like @code{Score} and @code{Staff}) not only store
568 properties, they also contain plug-ins called @q{engravers} that create
569 notation elements. For example, the @code{Voice} context contains a
570 @code{Note_heads_engraver} and the @code{Staff} context contains a
573 For a full a description of each plug-in, see
575 @rinternals{Engravers and Performers}.
578 Internals Reference @expansion{} Translation @expansion{} Engravers.
580 Every context described in
582 @rinternals{Contexts}
585 Internals Reference @expansion{} Translation @expansion{} Context.
587 lists the engravers used for that context.
590 It can be useful to shuffle around these plug-ins. This is done by
591 starting a new context with @code{\new} or @code{\context}, and
597 \new @var{context} \with @{
610 where the @dots{} should be the name of an engraver. Here is a simple
611 example which removes @code{Time_signature_engraver} and
612 @code{Clef_engraver} from a @code{Staff} context,
614 @lilypond[quote,relative=1,verbatim]
620 \remove "Time_signature_engraver"
621 \remove "Clef_engraver"
628 In the second staff there are no time signature or clef symbols. This
629 is a rather crude method of making objects disappear since it will affect
630 the entire staff. This method also influences the spacing, which may or
631 may not be desirable. More sophisticated methods of blanking objects
632 are shown in @rlearning{Visibility and color of objects}.
634 The next example shows a practical application. Bar lines and time
635 signatures are normally synchronized across the score. This is done
636 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
637 This plug-in keeps an administration of time signature, location
638 within the measure, etc. By moving these engraver from @code{Score} to
639 @code{Staff} context, we can have a score where each staff has its own
642 @cindex polymetric scores
643 @cindex Time signatures, multiple
645 @lilypond[quote,verbatim]
649 \consists "Timing_translator"
650 \consists "Default_bar_line_engraver"
656 \consists "Timing_translator"
657 \consists "Default_bar_line_engraver"
666 \remove "Timing_translator"
667 \remove "Default_bar_line_engraver"
675 Usually the order in which the engravers are specified
676 does not matter, but in a few special cases the order
677 is important, for example where one engraver writes
678 a property and another reads it, or where one engraver
679 creates a grob and another must process it. The order in
680 which the engravers are specified is the order in which
681 they are called to carry out their processing.
683 The following orderings are important: the
684 @code{Bar_engraver} must normally be first, and
685 the @code{New_fingering_engraver} must come before
686 the @code{Script_column_engraver}. There may be others
687 with ordering dependencies.
689 @node Changing context default settings
690 @subsection Changing context default settings
692 The context settings which are to be used by default in
693 @code{Score}, @code{Staff} and @code{Voice} contexts may be specified
694 in a @code{\layout} block, as illustrated in the following example.
695 The @code{\layout} block should be placed within the @code{\score}
696 block to which it is to apply, but outside any music.
698 Note that the @code{\set} command itself and the context must be
699 omitted when the context default values are specified in this way:
701 @lilypond[quote,verbatim]
704 a4^"Really small, thicker stems, no time signature" a a a
711 \override Stem #'thickness = #4.0
712 \remove "Time_signature_engraver"
718 In this example, the @code{\Staff} command specifies that the
719 subsequent specifications are to be applied to all staves within
722 Modifications can be made to the @code{Score} context or all
723 @code{Voice} contexts in a similar way.
725 Context changes can be placed in a variable and applied to a
726 @code{\context} definition by prepending the modification with
728 @lilypond[quote,verbatim]
731 \override Stem #'thickness = #4.0
732 \remove "Time_signature_engraver"
737 \override Stem #'thickness = #-2.0
740 melody = \relative c'' {
749 s1*0^"Small, thicker stems, no time signature"
765 @c TODO: add \with in here.
769 @node Defining new contexts
770 @subsection Defining new contexts
772 @cindex contexts, defining new
773 @cindex engravers, including in contexts
788 Specific contexts, like @code{Staff} and @code{Voice}, are made of
789 simple building blocks. It is possible to create new types of
790 contexts with different combinations of engraver plug-ins.
792 The next example shows how to build a different type of
793 @code{Voice} context from scratch. It will be similar to
794 @code{Voice}, but only prints centered slash note heads. It can be used
795 to indicate improvisation in jazz pieces,
797 @lilypond[quote,ragged-right]
800 \type "Engraver_group"
801 \consists "Note_heads_engraver"
802 \consists "Rhythmic_column_engraver"
803 \consists "Text_engraver"
804 \consists Pitch_squash_engraver
805 squashedPosition = #0
806 \override NoteHead #'style = #'slash
807 \override Stem #'transparent = ##t
808 \override Flag #'transparent = ##t
812 \accepts "ImproVoice"
816 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
817 c4 c^"undress" c_"while playing :)" c }
823 These settings are defined within a @code{\context} block inside a
824 @code{\layout} block,
834 In the following discussion, the example input shown should go in place
835 of the @dots{} in the previous fragment.
837 First it is necessary to define a name for the new context:
843 Since it is similar to the @code{Voice}, we want commands that work
844 on (existing) @code{Voice}s to remain working. This is achieved by
845 giving the new context an alias @code{Voice},
851 The context will print notes and instructive texts, so we need to add
852 the engravers which provide this functionality,
855 \consists Note_heads_engraver
856 \consists Text_engraver
859 but we only need this on the center line,
862 \consists Pitch_squash_engraver
863 squashedPosition = #0
866 The @rinternals{Pitch_squash_engraver} modifies note heads (created
867 by @rinternals{Note_heads_engraver}) and sets their vertical
868 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
871 The notes look like a slash, and have no stem,
874 \override NoteHead #'style = #'slash
875 \override Stem #'transparent = ##t
876 \override Flag #'transparent = ##t
879 All these plug-ins have to cooperate, and this is achieved with a
880 special plug-in, which must be marked with the keyword @code{\type}.
881 This should always be @code{Engraver_group}.
884 \type "Engraver_group"
892 \type "Engraver_group"
893 \consists "Note_heads_engraver"
894 \consists "Text_engraver"
895 \consists Pitch_squash_engraver
896 squashedPosition = #0
897 \override NoteHead #'style = #'slash
898 \override Stem #'transparent = ##t
899 \override Flag #'transparent = ##t
905 Contexts form hierarchies. We want to hang the @code{ImproVoice}
906 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
907 modify the @code{Staff} definition with the @code{\accepts}
918 The opposite of @code{\accepts} is @code{\denies},
919 which is sometimes needed when reusing existing context definitions.
921 Putting both into a @code{\layout} block, like
931 \accepts "ImproVoice"
936 Then the output at the start of this subsection can be entered as
944 c c_"while playing :)"
951 @node Context layout order
952 @subsection Context layout order
954 @cindex contexts, layout order
958 Contexts are normally positioned in a system from top to bottom
959 in the order in which they are encountered in the input file. When
960 contexts are nested, the outer context will include inner nested
961 contexts as specified in the input file, provided the inner contexts
962 are included in the outer context's @qq{accepts} list. Nested
963 contexts which are not included in the outer context's @qq{accepts}
964 list will be repositioned below the outer context rather than nested
967 The @qq{accepts} list of a context can be changed with the
968 @code{\accepts} and @code{\denies} commands. @code{\accepts} adds a
969 context to the @qq{accepts} list and @code{\denies} removes a context
970 from the list. For example, it would not normally be desirable for
971 chord names to be nested within a @code{Staff} context, so the
972 @code{ChordNames} context is not included by default in the @qq{accepts}
973 list of the @code{Staff} context, but if this were to be required it can
976 @lilypond[verbatim,quote]
980 \chords { d1:m7 b1:min7.5- }
985 @lilypond[verbatim,quote]
989 \chords { d1:m7 b1:min7.5- }
994 \accepts "ChordNames"
1000 @code{\denies} is mainly used when a new context is being based on
1001 another, but the required nesting differs. For example, the
1002 @code{VaticanaStaff} context is based on the @code{Staff} context, but
1003 with the @code{VaticanaVoice} context substituted for the @code{Voice}
1004 context in the @qq{accepts} list.
1006 Note that a context will be silently created implicitly if a command
1007 is encountered when there is no suitable context available to
1008 contain it. This can give rise to unexpected new staves or scores.
1012 @rprogram{An extra staff appears}.
1015 @file{ly/engraver-init.ly}.
1018 @node Explaining the Internals Reference
1019 @section Explaining the Internals Reference
1022 * Navigating the program reference::
1023 * Layout interfaces::
1024 * Determining the grob property::
1025 * Naming conventions::
1028 @node Navigating the program reference
1029 @subsection Navigating the program reference
1031 @c TODO remove this (it's in the LM)
1032 @c Replace with more factual directions
1034 Suppose we want to move the fingering indication in the fragment
1037 @lilypond[quote,relative=2,verbatim]
1043 If you visit the documentation on fingering instructions (in
1044 @ref{Fingering instructions}), you will notice:
1049 Internals Reference: @rinternals{Fingering}.
1054 @c outdated info; probably will delete.
1056 This fragment points to two parts of the program reference: a page
1057 on @code{FingeringEvent} and one on @code{Fingering}.
1059 The page on @code{FingeringEvent} describes the properties of the music
1060 expression for the input @w{@code{-2}}. The page contains many links
1061 forward. For example, it says
1064 Accepted by: @rinternals{Fingering_engraver},
1068 That link brings us to the documentation for the Engraver, the
1072 This engraver creates the following layout objects: @rinternals{Fingering}.
1075 In other words, once the @code{FingeringEvent}s are interpreted, the
1076 @code{Fingering_engraver} plug-in will process them.
1080 @c I can't figure out what this is supposed to mean. -gp
1082 The @code{Fingering_engraver} is also listed to create
1083 @rinternals{Fingering} objects,
1085 @c old info? it doesn't make any sense to me with our current docs.
1087 second bit of information listed under @b{See also} in the Notation
1092 The programmer's reference is available as an HTML document. It is
1093 highly recommended that you read it in HTML form, either online or
1094 by downloading the HTML documentation. This section will be much more
1095 difficult to understand if you are using the
1099 Follow the link to @rinternals{Fingering}. At the top of the
1103 Fingering objects are created by: @rinternals{Fingering_engraver} and
1104 @rinternals{New_fingering_engraver}.
1107 By following related links inside the program reference, we can follow the
1108 flow of information within the program:
1112 @item @rinternals{Fingering}:
1113 @rinternals{Fingering} objects are created by:
1114 @rinternals{Fingering_engraver}
1116 @item @rinternals{Fingering_engraver}:
1117 Music types accepted: @rinternals{fingering-event}
1119 @item @rinternals{fingering-event}:
1120 Music event type @code{fingering-event} is in Music expressions named
1121 @rinternals{FingeringEvent}
1124 This path goes against the flow of information in the program: it
1125 starts from the output, and ends at the input event. You could
1126 also start at an input event, and read with the flow of
1127 information, eventually ending up at the output object(s).
1129 The program reference can also be browsed like a normal document. It
1130 contains chapters on
1132 @rinternals{Music definitions},
1135 @code{Music definitions}
1137 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1138 chapter lists all the definitions used and all properties that may be
1142 @node Layout interfaces
1143 @subsection Layout interfaces
1145 @cindex interface, layout
1146 @cindex layout interface
1149 The HTML page that we found in the previous section describes the
1150 layout object called @rinternals{Fingering}. Such an object is a
1151 symbol within the score. It has properties that store numbers (like
1152 thicknesses and directions), but also pointers to related objects. A
1153 layout object is also called a @emph{Grob}, which is short for Graphical
1154 Object. For more details about Grobs, see @rinternals{grob-interface}.
1156 The page for @code{Fingering} lists the definitions for the
1157 @code{Fingering} object. For example, the page says
1160 @code{padding} (dimension, in staff space):
1166 which means that the number will be kept at a distance of at least 0.5
1170 Each layout object may have several functions as a notational or
1171 typographical element. For example, the Fingering object
1172 has the following aspects
1176 Its size is independent of the horizontal spacing, unlike slurs or beams.
1179 It is a piece of text. Granted, it is usually a very short text.
1182 That piece of text is typeset with a font, unlike slurs or beams.
1185 Horizontally, the center of the symbol should be aligned to the
1186 center of the note head.
1189 Vertically, the symbol is placed next to the note and the staff.
1192 The vertical position is also coordinated with other superscript
1193 and subscript symbols.
1196 Each of these aspects is captured in so-called @emph{interface}s,
1197 which are listed on the @rinternals{Fingering} page at the bottom
1200 This object supports the following interfaces:
1201 @rinternals{item-interface},
1202 @rinternals{self-alignment-interface},
1203 @rinternals{side-position-interface}, @rinternals{text-interface},
1204 @rinternals{text-script-interface}, @rinternals{font-interface},
1205 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1208 Clicking any of the links will take you to the page of the respective
1209 object interface. Each interface has a number of properties. Some of
1210 them are not user-serviceable (@q{Internal properties}), but others
1213 We have been talking of @emph{the} @code{Fingering} object, but actually it
1214 does not amount to much. The initialization file (see
1215 @rlearning{Other sources of information})
1216 @file{scm/define-grobs.scm} shows the soul of the @q{object},
1221 (avoid-slur . around)
1222 (slur-padding . 0.2)
1223 (staff-padding . 0.5)
1224 (self-alignment-X . 0)
1225 (self-alignment-Y . 0)
1226 (script-priority . 100)
1227 (stencil . ,ly:text-interface::print)
1228 (direction . ,ly:script-interface::calc-direction)
1229 (font-encoding . fetaText)
1230 (font-size . -5) ; don't overlap when next to heads.
1231 (meta . ((class . Item)
1232 (interfaces . (finger-interface
1234 text-script-interface
1236 side-position-interface
1237 self-alignment-interface
1238 item-interface))))))
1242 As you can see, the @code{Fingering} object is nothing more than a
1243 bunch of variable settings, and the webpage in the Internals Reference
1244 is directly generated from this definition.
1247 @node Determining the grob property
1248 @subsection Determining the grob property
1250 @c TODO remove this (it's in the LM)
1251 @c Replace with more factual directions
1253 Recall that we wanted to change the position of the @b{2} in
1255 @lilypond[quote,relative=2,verbatim]
1261 Since the @b{2} is vertically positioned next to its note, we have to
1262 meddle with the interface associated with this positioning. This is
1263 done using @code{side-position-interface}. The page for this interface
1267 @code{side-position-interface}
1269 Position a victim object (this one) next to other objects (the
1270 support). The property @code{direction} signifies where to put the
1271 victim object relative to the support (left or right, up or down?)
1276 Below this description, the variable @code{padding} is described as
1281 (dimension, in staff space)
1283 Add this much extra space between objects that are next to each other.
1287 By increasing the value of @code{padding}, we can move the
1288 fingering away from the note head. The following command inserts
1289 3 staff spaces of white
1290 between the note and the fingering:
1292 \once \override Voice.Fingering #'padding = #3
1295 Inserting this command before the Fingering object is created,
1296 i.e., before @code{c2}, yields the following result:
1298 @lilypond[quote,relative=2,verbatim]
1299 \once \override Voice.Fingering #'padding = #3
1306 In this case, the context for this tweak is @code{Voice}. This
1307 fact can also be deduced from the program reference, for the page for
1308 the @rinternals{Fingering_engraver} plug-in says
1311 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1315 @node Naming conventions
1316 @subsection Naming conventions
1318 Another thing that is needed, is an overview of the various naming
1322 @item scheme functions: lowercase-with-hyphens (incl. one-word
1324 @item scheme functions: ly:plus-scheme-style
1325 @item music events, music classes and music properties:
1327 @item Grob interfaces: scheme-style
1328 @item backend properties: scheme-style (but X and Y!)
1329 @item contexts (and MusicExpressions and grobs): Capitalized or
1331 @item context properties: lowercaseFollowedByCamelCase
1333 Capitalized_followed_by_lowercase_and_with_underscores
1336 Questions to be answered:
1338 @item Which of these are conventions and which are rules?
1339 @item Which are rules of the underlying language, and which are
1343 @node Modifying properties
1344 @section Modifying properties
1346 @c TODO change the menu and subsection node names to use
1347 @c backslash once the new macro to handle the refs
1348 @c is available. Need to find and change all refs at
1349 @c the same time. -td
1352 * Overview of modifying properties::
1354 * The override command::
1355 * The tweak command::
1356 * set versus override::
1357 * Modifying alists::
1361 @node Overview of modifying properties
1362 @subsection Overview of modifying properties
1364 Each context is responsible for creating certain types of graphical
1365 objects. The settings used for printing these objects are also stored by
1366 context. By changing these settings, the appearance of objects can be
1369 There are two different kinds of properties stored in contexts:
1370 context properties and grob properties. Context properties are
1371 properties that apply to the context as a whole and control
1372 how the context itself is displayed. In contrast, grob properties
1373 apply to specific grob types that will be displayed in the context.
1375 The @code{\set} and @code{\unset} commands are used to change values
1376 for context properties. The @code{\override} and @code{\revert}
1377 commands are used to change values for grob properties.
1380 The syntax for this is
1383 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1386 Here @var{name} is the name of a graphical object, like
1387 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1388 variable of the formatting system (@q{grob property} or @q{layout
1389 property}). The latter is a symbol, so it must be quoted. The
1390 subsection @ref{Modifying properties}, explains what to fill in
1391 for @var{name}, @var{property}, and @var{value}. Here we only
1392 discuss the functionality of this command.
1397 \override Staff.Stem #'thickness = #4.0
1401 makes stems thicker (the default is 1.3, with staff line thickness as a
1402 unit). Since the command specifies @code{Staff} as context, it only
1403 applies to the current staff. Other staves will keep their normal
1404 appearance. Here we see the command in action:
1406 @lilypond[quote,verbatim,relative=2]
1408 \override Staff.Stem #'thickness = #4.0
1414 The @code{\override} command changes the definition of the @code{Stem}
1415 within the current @code{Staff}. After the command is interpreted
1416 all stems are thickened.
1418 Analogous to @code{\set}, the @var{context} argument may be left out,
1419 causing the default context @code{Voice} to be used. Adding
1420 @code{\once} applies the change during one timestep only.
1422 @lilypond[quote,verbatim,relative=2]
1424 \once \override Stem #'thickness = #4.0
1429 The @code{\override} must be done before the object is
1430 started. Therefore, when altering @emph{Spanner} objects such as slurs
1431 or beams, the @code{\override} command must be executed at the moment
1432 when the object is created. In this example,
1434 @lilypond[quote,verbatim,relative=2]
1435 \override Slur #'thickness = #3.0
1437 \override Beam #'beam-thickness = #0.6
1442 the slur is fatter but the beam is not. This is because the command for
1443 @code{Beam} comes after the Beam is started, so it has no effect.
1445 Analogous to @code{\unset}, the @code{\revert} command for a context
1446 undoes an @code{\override} command; like with @code{\unset}, it only
1447 affects settings that were made in the same context. In other words, the
1448 @code{\revert} in the next example does not do anything.
1451 \override Voice.Stem #'thickness = #4.0
1452 \revert Staff.Stem #'thickness
1455 Some tweakable options are called @q{subproperties} and reside inside
1456 properties. To tweak those, use commands of the form
1458 @c leave this as a long long
1460 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1467 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1473 Internals Reference:
1474 @rinternals{Backend},
1475 @rinternals{All layout objects},
1476 @rinternals{OverrideProperty},
1477 @rinternals{RevertProperty},
1478 @rinternals{PropertySet}.
1481 The back-end is not very strict in type-checking object properties.
1482 Cyclic references in Scheme values for properties can cause hangs
1483 or crashes, or both.
1486 @node The set command
1487 @subsection The @code{@bs{}set} command
1491 @cindex changing properties
1493 Each context has a set of @emph{properties}, variables contained
1494 in that context. Context properties are changed with the @code{\set}
1495 command, which has the following syntax:
1498 \set @var{context}.@var{property} = #@var{value}
1501 @var{value} is a Scheme object, which is why it must be preceded by
1502 the @code{#}@tie{}character.
1504 Contexts properties are usually named in
1505 @code{studlyCaps}. They mostly control the translation from
1506 music to notation, e.g. @code{localKeySignature} (for determining
1507 whether to print accidentals), or @code{measurePosition} (for
1508 determining when to print a bar line). Context properties can
1509 change value over time while interpreting a piece of music;
1510 @code{measurePosition} is an obvious example of
1511 this. Context properties are modified with @code{\set}.
1513 For example, multimeasure rests will be combined into a single bar
1514 if the context property @code{skipBars} is set to @code{#t}:
1516 @lilypond[quote,verbatim,relative=2]
1518 \set Score.skipBars = ##t
1522 If the @var{context} argument is left out, then the property will be
1523 set in the current bottom context (typically @code{ChordNames},
1524 @code{Voice}, @code{TabVoice}, or @code{Lyrics}).
1526 @lilypond[quote,verbatim,relative=2]
1527 \set Score.autoBeaming = ##f
1531 \set autoBeaming = ##t
1539 The change is applied @q{on-the-fly}, during the music, so that the
1540 setting only affects the second group of eighth notes.
1542 Note that the bottom-most context does not always contain the property
1543 that you wish to change -- for example, attempting to set the
1544 @code{skipBars} property of the default bottom context, in this case
1545 @code{Voice}, will have no effect, because skipBars is a property of
1546 the @code{Score} context.
1548 @lilypond[quote,verbatim,relative=2]
1554 Contexts are hierarchical, so if an enclosing context was specified, for
1555 example @code{Staff}, then the change would also apply to all
1556 @code{Voice}s in the current staff.
1560 The @code{\unset} command:
1563 \unset @var{context}.@var{property}
1567 is used to remove the definition of @var{property} from
1568 @var{context}. This command removes
1569 the definition only if it is set in @var{context}.
1570 Properties that have been set in enclosing contexts will
1571 not be altered by an unset in an enclosed context:
1573 @lilypond[quote,verbatim,relative=2]
1574 \set Score.autoBeaming = ##t
1579 \unset Score.autoBeaming
1587 Like @code{\set}, the @var{context} argument does not have to be
1588 specified for a bottom context, so the two statements
1591 \set Voice.autoBeaming = ##t
1592 \set autoBeaming = ##t
1596 are equivalent if the current bottom context is @code{Voice}.
1600 Preceding a @code{\set} command by @code{\once} makes the
1601 setting apply to only a single time-step:
1603 @lilypond[quote,verbatim,relative=2]
1605 \once \set fontSize = #4.7
1610 A full description of all available context properties is in the
1611 internals reference, see
1613 @rinternals{Tunable context properties}.
1616 Translation @expansion{} Tunable context properties.
1620 Internals Reference:
1621 @rinternals{Tunable context properties}.
1623 @cindex grob properties
1624 @cindex properties, grob
1628 @node The override command
1629 @subsection The @code{\override} command
1631 There is a special type of context property: the grob
1632 description. Grob descriptions are named in @code{StudlyCaps}
1633 (starting with capital letters). They contain the
1634 @q{default settings} for a particular kind of grob as an
1635 association list. See @file{scm/define-grobs.scm}
1636 to see the settings for each grob description. Grob descriptions
1637 are modified with @code{\override}.
1639 @code{\override} is actually a shorthand;
1642 \override @var{context}.@var{GrobName} #'@var{property} = #@var{value}
1646 is more or less equivalent to
1648 @c leave this long line -gp
1650 \set @var{context}.@var{GrobName} =
1651 #(cons (cons '@var{property} @var{value})
1652 <previous value of @var{context}.@var{GrobName}>)
1655 The value of @code{context}.@code{GrobName} (the alist) is used to initialize
1656 the properties of individual grobs. Grobs have
1657 properties, named in Scheme style, with
1658 @code{dashed-words}. The values of grob properties change
1659 during the formatting process: formatting basically amounts
1660 to computing properties using callback functions.
1662 For example, we can increase the thickness of a note stem by
1663 overriding the @code{thickness} property of the @code{Stem}
1666 @lilypond[quote,verbatim,relative=2]
1668 \override Voice.Stem #'thickness = #3.0
1672 If no context is specified in an @code{\override}, the bottom
1675 @lilypond[quote,verbatim,relative=2]
1676 { \override Staff.Stem #'thickness = #3.0
1680 \override Stem #'thickness = #0.5
1690 @cindex reverting overrides
1691 @cindex overrides, reverting
1693 The effects of @code{\override} can be undone by @code{\revert}:
1695 @lilypond[quote,verbatim,relative=2]
1697 \override Voice.Stem #'thickness = #3.0
1699 \revert Voice.Stem #'thickness
1703 The effects of @code{\override} and @code{\revert} apply to all
1704 grobs in the affected context from the current time forward:
1706 @lilypond[quote,verbatim,relative=2]
1711 \override Staff.Stem #'thickness = #3.0
1715 \revert Staff.Stem #'thickness
1723 @cindex overriding for only one moment
1725 @code{\once} can be used with @code{\override}
1726 to affect only the current time step:
1728 @lilypond[quote,verbatim,relative=2]
1732 \override Stem #'thickness = #3.0
1736 \once \override Stem #'thickness = #3.0
1745 Commands which change output generally look like
1748 \override Voice.Stem #'thickness = #3.0
1752 To construct this tweak we must determine these bits of information:
1755 @item the context: here @code{Voice}.
1756 @item the layout object: here @code{Stem}.
1757 @item the layout property: here @code{thickness}.
1758 @item a sensible value: here @code{3.0}.
1761 Some tweakable options are called @q{subproperties} and reside inside
1762 properties. To tweak those, use commands in the form
1765 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1768 @cindex internal documentation
1769 @cindex finding graphical objects
1770 @cindex graphical object descriptions
1773 @cindex internal documentation
1775 For many properties, regardless of the data type of the property, setting the
1776 property to false (@code{#f}) will result in turning it off, causing
1777 LilyPond to ignore that property entirely. This is particularly useful for
1778 turning off grob properties which may otherwise be causing problems.
1780 We demonstrate how to glean this information from the notation manual
1781 and the program reference.
1785 Internals Reference:
1786 @rinternals{Backend}
1789 @node The tweak command
1790 @subsection The @code{\tweak} command
1795 Changing grob properties
1796 with @code{\override} causes the changes to apply to all of the
1797 given grobs in the context at the moment the change applies.
1798 Sometimes, however, it is desirable to have changes apply to just
1799 one grob, rather than to all grobs in the affected context. This is
1800 accomplished with the @code{\tweak} command, which has the following
1804 \tweak #'@code{grob-property} #@code{value}
1807 The @code{\tweak} command applies to the object that immediately
1808 follows @code{value} in the music stream.
1811 In some cases, it is possible to take a short-cut for tuning
1812 graphical objects. For objects that are created directly from
1813 an item in the input file, you can use the @code{\tweak} command.
1816 @lilypond[relative=2,verbatim,quote]
1821 \tweak #'duration-log #1
1824 -\tweak #'padding #8
1830 But the main use of the @code{\tweak} command is to modify just
1831 one of a number of notation elements which start at the same musical
1832 moment, like the notes of a chord, or tuplet brackets which start
1835 The @code{\tweak} command sets a property in the following object
1836 directly, without requiring the grob name or context to be
1837 specified. For this to work, it is necessary for the @code{\tweak}
1838 command to remain immediately adjacent to the object to which it is
1839 to apply after the input file has been converted to a music stream.
1840 This is often not the case, as many additional elements are inserted
1841 into the music stream implicitly. For example, when a note which is
1842 not part of a chord is processed, LilyPond implicitly inserts a
1843 @code{ChordEvent} event before the note, so separating the tweak
1844 from the note. However, if chord symbols are placed round the
1845 tweak and the note, the @code{\tweak} command comes after the
1846 @code{ChordEvent} in the music stream, so remaining adjacent to the
1847 note, and able to modify it.
1851 @lilypond[relative=2,verbatim,quote]
1852 <\tweak #'color #red c>4
1858 @lilypond[relative=2,verbatim,quote]
1859 \tweak #'color #red c4
1864 For an introduction to the syntax and uses of the tweak command
1865 see @rlearning{Tweaking methods}.
1867 When several similar items are placed at the same musical moment,
1868 the @code{\override} command cannot be used to modify just one of
1869 them -- this is where the @code{\tweak} command must be used.
1870 Items which may appear more than once at the same musical moment
1871 include the following:
1873 @c TODO expand to include any further uses of \tweak
1875 @item note heads of notes inside a chord
1876 @item articulation signs on a single note
1877 @item ties between notes in a chord
1878 @item tuplet brackets starting at the same time
1881 @c TODO add examples of these
1883 @cindex chord, modifying one note in
1885 In this example, the color of one note head and the type of another
1886 note head are modified within a single chord:
1888 @lilypond[relative=2,verbatim,quote]
1893 \tweak #'duration-log #1
1898 @code{\tweak} can be used to modify slurs:
1900 @lilypond[verbatim,quote,relative=1]
1901 c-\tweak #'thickness #5 ( d e f)
1905 For the @code{\tweak} command to work, it must
1906 remain immediately adjacent to the object to which it is
1907 to apply after the input file has been converted to a music stream.
1908 At times, LilyPond may insert additional items into the music stream
1909 during the parsing process. For example, when a note that is not
1910 explicitly part of a chord will be placed in a chord by LilyPond,
1911 so notes to be modified with @code{\tweak} must be placed inside
1914 @lilypond[relative=2,verbatim,quote]
1915 \tweak #'color #red c4
1916 <\tweak #'color #red c>4
1919 The @code{\tweak} command cannot be used to modify any item
1920 that does not appear explicitly in the input file. In particular
1921 it cannot be used to modify stems,
1922 beams or accidentals directly, since these are generated later by
1923 note heads, rather than by music elements in the input stream.
1924 Nor can @code{\tweak} be used to modify clefs or time
1925 signatures, since these become separated from any preceding
1926 @code{\tweak} command in the input stream by the automatic
1927 insertion of extra elements required to specify the context.
1929 Several @code{\tweak} commands may be placed before a
1930 notational element -- all affect it:
1932 @lilypond[verbatim,quote,relative=1]
1934 -\tweak #'style #'dashed-line
1935 -\tweak #'dash-fraction #0.2
1936 -\tweak #'thickness #3
1937 -\tweak #'color #red
1942 The music stream which is generated from a section of an input file,
1943 including any automatically inserted elements, may be examined,
1944 see @rextend{Displaying music expressions}. This may be helpful in
1945 determining what may be modified by a @code{\tweak} command, or
1946 in determining how to adjust the input to make a @code{\tweak}
1951 @rlearning{Tweaking methods}.
1954 @rextend{Displaying music expressions}.
1957 @cindex tweaks in a variable
1959 The @code{\tweak} command cannot be used inside a variable.
1961 @cindex tweaks in lyrics
1962 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1964 @cindex tweaking control points
1965 @cindex control points, tweaking
1967 The @code{\tweak} command will apply to only the first of several
1968 generated ties in a chord.
1971 @node set versus override
1972 @subsection @code{\set} vs. @code{\override}
1974 @c TODO -- This section is probably unnecessary now.
1977 We have seen two methods of changing properties: @code{\set} and
1978 @code{\override}. There are actually two different kinds of
1981 @code{fontSize} is a special property: it is equivalent to
1982 entering @code{\override ... #'font-size} for all pertinent
1983 objects. Since this is a common change, the special
1984 property (modified with @code{\set}) was created.
1989 @node Modifying alists
1990 @subsection Modifying alists
1992 Some user-configurable properties are internally represented as
1993 @emph{alists} (association lists), which store pairs of
1994 @emph{keys} and @emph{values}. The structure of an alist is:
1997 '((@var{key1} . @var{value1})
1998 (@var{key2} . @var{value2})
1999 (@var{key3} . @var{value3})
2003 If an alist is a grob property or @code{\paper} variable, its keys
2004 can be modified individually without affecting other keys.
2006 For example, to reduce the space between adjacent staves in a
2007 staff-group, use the @code{staff-staff-spacing} property of the
2008 @code{StaffGrouper} grob. The property is an alist with four
2009 keys: @code{basic-distance}, @code{minimum-distance},
2010 @code{padding}, and @code{stretchability}. The standard settings
2011 for this property are listed in the @qq{Backend} section of the
2012 Internals Reference (see @rinternals{StaffGrouper}):
2015 '((basic-distance . 9)
2016 (minimum-distance . 7)
2018 (stretchability . 5))
2021 One way to bring the staves closer together is by reducing the
2022 value of the @code{basic-distance} key (@code{9}) to match the
2023 value of @code{minimum-distance} (@code{7}). To modify a single
2024 key individually, use a @emph{nested declaration}:
2026 @lilypond[quote,verbatim]
2027 % default space between staves
2029 \new Staff { \clef treble c''1 }
2030 \new Staff { \clef bass c1 }
2033 % reduced space between staves
2034 \new PianoStaff \with {
2035 % this is the nested declaration
2036 \override StaffGrouper #'staff-staff-spacing #'basic-distance = #7
2038 \new Staff { \clef treble c''1 }
2039 \new Staff { \clef bass c1 }
2043 Using a nested declaration will update the specified key (such as
2044 @code{basic-distance} in the above example) without altering any
2045 other keys already set for the same property.
2047 Now suppose we want the staves to be as close as possible without
2048 overlapping. The simplest way to do this is to set all four alist
2049 keys to zero. However, it is not necessary to enter four nested
2050 declarations, one for each key. Instead, the property can be
2051 completely re-defined with one declaration, as an alist:
2053 @lilypond[quote,verbatim]
2054 \new PianoStaff \with {
2055 \override StaffGrouper #'staff-staff-spacing =
2056 #'((basic-distance . 0)
2057 (minimum-distance . 0)
2059 (stretchability . 0))
2061 \new Staff { \clef treble c''1 }
2062 \new Staff { \clef bass c1 }
2066 Note that any keys not explicitly listed in the alist definition
2067 will be reset to their @emph{default-when-unset} values. In the
2068 case of @code{staff-staff-spacing}, any unset key-values would be
2069 reset to zero (except @code{stretchability}, which takes the value
2070 of @code{basic-distance} when unset). Thus the following two
2071 declarations are equivalent:
2074 \override StaffGrouper #'staff-staff-spacing =
2075 #'((basic-distance . 7))
2077 \override StaffGrouper #'staff-staff-spacing =
2078 #'((basic-distance . 7)
2079 (minimum-distance . 0)
2081 (stretchability . 7))
2084 One (possibly unintended) consequence of this is the removal of
2085 any standard settings that are set in an initialization file and
2086 loaded each time an input file is compiled. In the above example,
2087 the standard settings for @code{padding} and
2088 @code{minimum-distance} (defined in @file{scm/define-grobs.scm})
2089 are reset to their default-when-unset values (zero for both keys).
2090 Defining a property or variable as an alist (of any size) will
2091 always reset all unset key-values to their default-when-unset
2092 values. Unless this is the intended result, it is safer to update
2093 key-values individually with a nested declaration.
2095 @warning{Nested declarations will not work for context property
2096 alists (such as @code{beamExceptions}, @code{keySignature},
2097 @code{timeSignatureSettings}, etc.). These properties can only be
2098 modified by completely re-defining them as alists.}
2101 @node Useful concepts and properties
2102 @section Useful concepts and properties
2107 * Direction and placement::
2108 * Distances and measurements::
2109 * Staff symbol properties::
2111 * Visibility of objects::
2113 * Rotating objects::
2117 @subsection Input modes
2119 The way in which the notation contained within an input file is
2120 interpreted is determined by the current input mode.
2124 This is activated with the @code{\chordmode} command, and causes
2125 input to be interpreted with the syntax of chord notation, see
2126 @ref{Chord notation}. Chords are rendered as notes on a staff.
2128 Chord mode is also activated with the @code{\chords} command.
2129 This also creates a new @code{ChordNames} context and
2130 causes the following input to be interpreted with the syntax of
2131 chord notation and rendered as chord names in the @code{ChordNames}
2132 context, see @ref{Printing chord names}.
2136 This is activated with the @code{\drummode} command, and causes
2137 input to be interpreted with the syntax of drum notation, see
2138 @ref{Basic percussion notation}.
2140 Drum mode is also activated with the @code{\drums} command.
2141 This also creates a new @code{DrumStaff} context and causes the
2142 following input to be interpreted with the syntax of drum notation
2143 and rendered as drum symbols on a drum staff, see @ref{Basic
2144 percussion notation}.
2146 @strong{Figure mode}
2148 This is activated with the @code{\figuremode} command, and causes
2149 input to be interpreted with the syntax of figured bass, see
2150 @ref{Entering figured bass}.
2152 Figure mode is also activated with the @code{\figures} command.
2153 This also creates a new @code{FiguredBass} context and causes the
2154 following input to be interpreted with the figured bass syntax
2155 and rendered as figured bass symbols in the @code{FiguredBass}
2156 context, see @ref{Introduction to figured bass}.
2158 @strong{Fret and tab modes}
2160 There are no special input modes for entering fret and tab symbols.
2162 To create tab diagrams, enter notes or chords in note mode and
2163 render them in a @code{TabStaff} context, see
2164 @ref{Default tablatures}.
2166 To create fret diagrams above a staff, you have two choices.
2167 You can either use the @code{FretBoards} context (see
2168 @ref{Automatic fret diagrams} or you can enter them as a markup
2169 above the notes using the @code{\fret-diagram} command (see
2170 @ref{Fret diagram markups}).
2172 @strong{Lyrics mode}
2174 This is activated with the @code{\lyricmode} command, and causes
2175 input to be interpreted as lyric syllables with optional durations
2176 and associated lyric modifiers, see @ref{Vocal music}.
2178 Lyric mode is also activated with the @code{\addlyrics} command.
2179 This also creates a new @code{Lyrics} context and an implicit
2180 @code{\lyricsto} command which associates the following lyrics
2181 with the preceding music.
2183 @strong{Markup mode}
2185 This is activated with the @code{\markup} command, and causes
2186 input to be interpreted with the syntax of markup, see
2187 @ref{Text markup commands}.
2189 @c silly work-around for texinfo broken-ness
2190 @c (@strong{Note...} causes a spurious cross-reference in Info)
2193 This is the default mode or it may be activated with the
2194 @code{\notemode} command. Input is interpreted as pitches,
2195 durations, markup, etc and typeset as musical notation on a staff.
2197 It is not normally necessary to specify note mode explicitly, but
2198 it may be useful to do so in certain situations, for example if you
2199 are in lyric mode, chord mode or any other mode and want to insert
2200 something that only can be done with note mode syntax.
2202 For example, to indicate dynamic markings for the verses of a
2203 choral pieces it is necessary to enter note mode to interpret
2206 @lilypond[verbatim,relative=2,quote]
2209 \notemode{\set stanza = \markup{ \dynamic f 1. } }
2213 \notemode{\set stanza = \markup{ \dynamic p 2. } }
2220 @node Direction and placement
2221 @subsection Direction and placement
2223 In typesetting music the direction and placement of many items is
2224 a matter of choice. For example, the stems of notes can
2225 be directed up or down; lyrics, dynamics, and other expressive
2226 marks may be placed above or below the staff; text may be aligned
2227 left, right or center; etc. Most of these choices may be left to
2228 be determined automatically by LilyPond, but in some cases it may
2229 be desirable to force a particular direction or placement.
2231 @strong{Articulation direction indicators}
2233 By default some directions are always up or always down (e.g.
2234 dynamics or fermata), while other things can alternate between
2235 up or down based on the stem direction (like slurs or accents).
2237 @c TODO Add table showing these
2239 The default action may be overridden by prefixing the articulation
2240 by a @emph{direction indicator}. Three direction indicators are
2241 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
2242 and @code{-} (meaning @qq{use default direction}). The direction
2243 indicator can usually be omitted, in which case @code{-} is assumed,
2244 but a direction indicator is @strong{always} required before
2247 @item @code{\tweak} commands
2248 @item @code{\markup} commands
2249 @item @code{\tag} commands
2250 @item string markups, e.g. -"string"
2251 @item fingering instructions, e.g. @w{@code{-1}}
2252 @item articulation shortcuts, e.g. @w{@code{-.}}, @w{@code{->}}, @w{@code{--}}
2255 Direction indicators affect only the next note:
2257 @lilypond[verbatim,quote,relative=2]
2264 @strong{The direction property}
2266 The position or direction of many layout objects is controlled by the
2267 @code{direction} property.
2269 The value of the @code{direction} property may be set to @code{1},
2270 meaning @qq{up} or @qq{above}, or to @w{@code{-1}}, meaning @qq{down} or
2271 @qq{below}. The symbols @code{UP} and @code{DOWN} may be used instead
2272 of @code{1} and @w{@code{-1}} respectively. The default direction may
2273 be specified by setting @code{direction} to @code{0} or @code{CENTER}.
2274 Alternatively, in many cases predefined commands exist to specify the
2275 direction. These are of the form
2278 @code{\xxxUp}, @code{\xxxDown} or @code{\xxxNeutral}
2282 where @code{\xxxNeutral} means @qq{use the default} direction.
2283 See @rlearning{Within-staff objects}.
2285 In a few cases, arpeggio for example, the value of the @code{direction}
2286 property can specify whether the object is to be placed to the right or
2287 left of the parent. In this case @w{@code{-1}} or @code{LEFT} means
2288 @qq{to the left} and @code{1} or @code{RIGHT} means @qq{to the right}.
2289 @code{0} or @code{CENTER} means @qq{use the default} direction.
2292 These all have side-axis set to #X
2293 AmbitusAccidental - direction has no effect
2295 StanzaNumber - not tried
2296 TrillPitchAccidental - not tried
2297 TrillPitchGroup - not tried
2300 These indications affect all notes until they are canceled.
2302 @lilypond[verbatim,quote,relative=2]
2311 In polyphonic music, it is generally better to specify an explicit
2312 @code{voice} than change an object's direction. For more information.
2313 See @ref{Multiple voices}.
2317 @rlearning{Within-staff objects}.
2320 @ref{Multiple voices}.
2323 @node Distances and measurements
2324 @subsection Distances and measurements
2326 @cindex distances, absolute
2327 @cindex distances, scaled
2334 Distances in LilyPond are of two types: absolute and scaled.
2336 Absolute distances are used for specifying margins, indents, and
2337 other page layout details, and are by default specified in
2338 millimeters. Distances may be specified in other units by
2339 following the quantity by @code{\mm}, @code{\cm},
2340 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27 of
2341 an inch). Page layout distances can also be specified in scalable
2342 units (see the following paragraph) by appending
2343 @code{\staff-space} to the quantity. Page layout is described in
2344 detail in @ref{Page layout}.
2346 Scaled distances are always specified in units of the staff-space
2347 or, rarely, the half staff-space. The staff-space is the distance
2348 between two adjacent staff lines. The default value can be changed
2349 globally by setting the global staff size, or it can be overridden
2350 locally by changing the @code{staff-space} property of
2351 @code{StaffSymbol}. Scaled distances automatically scale with any
2352 change to the either the global staff size or the
2353 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2354 automatically only with changes to the global staff size.
2355 The global staff size thus enables the overall size of a rendered
2356 score to be easily varied. For the methods of setting the global
2357 staff size see @ref{Setting the staff size}.
2361 If just a section of a score needs to be rendered to a different
2362 scale, for example an ossia section or a footnote, the global staff
2363 size cannot simply be changed as this would affect the entire score.
2364 In such cases the change in size is made by overriding both the
2365 @code{staff-space} property of @code{StaffSymbol} and the size of
2366 the fonts. A Scheme function, @code{magstep}, is available to
2367 convert from a font size change to the equivalent change in
2368 @code{staff-space}. For an explanation and an example of its use,
2369 see @rlearning{Length and thickness of objects}.
2373 @rlearning{Length and thickness of objects}.
2377 @ref{Setting the staff size}.
2380 @node Staff symbol properties
2381 @subsection Staff symbol properties
2383 @cindex adjusting staff symbol
2384 @cindex drawing staff symbol
2385 @cindex staff symbol, setting of
2387 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2388 @c Need to think of uses for these properties. Eg 'line-positions
2389 @c is used in a snippet to thicken centre line.
2390 @c If retained, add @ref to here in 1.6.2 -td
2392 The vertical position of staff lines and the number of staff lines
2393 can be defined at the same time. As the following example shows,
2394 note positions are not influenced by the staff line positions.
2396 @warning{The @code{'line-positions} property overrides the
2397 @code{'line-count} property. The number of staff lines is
2398 implicitly defined by the number of elements in the list of values
2399 for @code{'line-positions}.}
2401 @lilypond[verbatim,quote,relative=1]
2403 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
2408 The width of a staff can be modified. The units are staff
2409 spaces. The spacing of objects inside the staff is not affected by
2412 @lilypond[verbatim,quote,relative=1]
2414 \override StaffSymbol #'width = #23
2421 @subsection Spanners
2423 Many objects of musical notation extend over several notes or even
2424 several bars. Examples are slurs, beams, tuplet brackets, volta
2425 repeat brackets, crescendi, trills, and glissandi. Such objects
2426 are collectively called @qq{spanners}, and have special properties to control
2427 their appearance and behaviour. Some of these properties are common
2428 to all spanners; others are restricted to a sub-set of the spanners.
2430 All spanners support the @code{spanner-interface}. A few, essentially
2431 those that draw a straight line between the two objects, support in
2432 addition the @code{line-spanner-interface}.
2434 @unnumberedsubsubsec Using the @code{spanner-interface}
2436 This interface provides two properties that apply to several spanners.
2438 @strong{@i{The @code{minimum-length} property}}
2440 The minimum length of the spanner is specified by the
2441 @code{minimum-length} property. Increasing this usually has the
2442 necessary effect of increasing the spacing of the notes between the
2443 two end points. However, this override has no effect on
2444 many spanners, as their length is determined by other considerations.
2445 A few examples where it is effective are shown below.
2455 Works as long as callback is made:
2459 Works not at all for:
2468 @lilypond[verbatim,quote,relative=2]
2471 % increase the length of the tie
2472 -\tweak #'minimum-length #5
2476 @lilypond[verbatim,quote,relative=2]
2478 \compressFullBarRests
2480 % increase the length of the rest bar
2481 \once \override MultiMeasureRest #'minimum-length = #20
2486 @lilypond[verbatim,quote,relative=2]
2488 % increase the length of the hairpin
2489 \override Hairpin #'minimum-length = #20
2493 This override can also be used to increase the length of slurs and
2496 @lilypond[verbatim,quote,relative=2]
2499 -\tweak #'minimum-length #5
2504 -\tweak #'minimum-length #5
2508 For some layout objects, the @code{minimum-length} property becomes
2509 effective only if the @code{set-spacing-rods} procedure is called
2510 explicitly. To do this, the @code{springs-and-rods} property should
2511 be set to @code{ly:spanner::set-spacing-rods}. For example,
2512 the minimum length of a glissando has no effect unless the
2513 @code{springs-and-rods} property is set:
2515 @lilypond[verbatim,quote,relative=1]
2519 % not effective alone
2520 \once \override Glissando #'minimum-length = #20
2523 % effective only when both overrides are present
2524 \once \override Glissando #'minimum-length = #20
2525 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2529 The same is true of the @code{Beam} object:
2531 @lilypond[verbatim,quote,relative=1]
2532 % not effective alone
2533 \once \override Beam #'minimum-length = #20
2536 % effective only when both overrides are present
2537 \once \override Beam #'minimum-length = #20
2538 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2542 @strong{@i{The @code{to-barline} property}}
2544 The second useful property of the @code{spanner-interface} is
2545 @code{to-barline}. By default this is true, causing hairpins and
2546 other spanners which are terminated on the first note of a measure to
2547 end instead on the immediately preceding bar line. If set to false,
2548 the spanner will extend beyond the bar line and end on the note
2551 @lilypond[verbatim,quote,relative=2]
2552 a \< a a a a \! a a a \break
2553 \override Hairpin #'to-barline = ##f
2554 a \< a a a a \! a a a
2557 This property is not effective for all spanners. For example,
2558 setting it to @code{#t} has no effect on slurs or phrasing slurs
2559 or on other spanners for which terminating on the bar line would
2562 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2564 Objects which support the @code{line-spanner-interface} include
2567 @item @code{DynamicTextSpanner}
2568 @item @code{Glissando}
2569 @item @code{TextSpanner}
2570 @item @code{TrillSpanner}
2571 @item @code{VoiceFollower}
2574 The routine responsible for drawing the stencils for these spanners is
2575 @code{ly:line-interface::print}. This routine determines the
2576 exact location of the two end points and draws a line
2577 between them, in the style requested. The locations of the two
2578 end points of the spanner are computed on-the-fly, but it is
2579 possible to override their Y-coordinates. The
2580 properties which need to be specified are nested
2581 two levels down within the property hierarchy, but the syntax of
2582 the @code{\override} command is quite simple:
2584 @lilypond[relative=2,quote,verbatim]
2586 \once \override Glissando #'(bound-details left Y) = #3
2587 \once \override Glissando #'(bound-details right Y) = #-2
2591 The units for the @code{Y} property are @code{staff-space}s,
2592 with the center line of the staff being the zero point.
2593 For the glissando, this is the value for @code{Y} at the
2594 X-coordinate corresponding to the center point of each note head,
2595 if the line is imagined to be extended to there.
2597 If @code{Y} is not set, the value is computed from the vertical
2598 position of the corresponding attachment point of the spanner.
2600 In case of a line break, the values for the end points are
2601 specified by the @code{left-broken} and @code{right-broken}
2602 sub-lists of @code{bound-details}. For example:
2604 @lilypond[relative=2,ragged-right,verbatim,quote]
2605 \override Glissando #'breakable = ##t
2606 \override Glissando #'(bound-details right-broken Y) = #-3
2607 c1 \glissando \break
2612 A number of further properties of the @code{left} and
2613 @code{right} sub-lists of the @code{bound-details} property
2614 may be modified in the same way as @code{Y}:
2618 This sets the Y-coordinate of the end point, in @code{staff-space}s
2619 offset from the staff center line. By default, it is the center of
2620 the bound object, so a glissando points to the vertical center of
2623 For horizontal spanners, such as text spanners and trill spanners,
2624 it is hardcoded to 0.
2627 This determines where the line starts and ends in the X-direction,
2628 relative to the bound object. So, a value of @w{@code{-1}} (or
2629 @code{LEFT}) makes the line start/end at the left side of the note
2630 head it is attached to.
2633 This is the absolute X-coordinate of the end point. It is usually
2634 computed on the fly, and overriding it has little useful effect.
2637 Line spanners may have symbols at the beginning or end, which is
2638 contained in this sub-property. This is for internal use; it is
2639 recommended that @code{text} be used instead.
2642 This is a markup that is evaluated to yield the stencil. It is used
2643 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2645 @lilypond[quote,ragged-right,relative=2,verbatim]
2646 \override TextSpanner #'(bound-details left text)
2647 = \markup { \small \bold Slower }
2648 c2\startTextSpan b c a\stopTextSpan
2651 @item stencil-align-dir-y
2652 @item stencil-offset
2653 Without setting one of these, the stencil is simply put at the
2654 end-point, centered on the line, as defined by the @code{X} and
2655 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2656 or @code{stencil-offset} will move the symbol at the edge vertically
2657 relative to the end point of the line:
2659 @lilypond[relative=1,quote,verbatim]
2660 \override TextSpanner
2661 #'(bound-details left stencil-align-dir-y) = #-2
2662 \override TextSpanner
2663 #'(bound-details right stencil-align-dir-y) = #UP
2665 \override TextSpanner
2666 #'(bound-details left text) = #"ggg"
2667 \override TextSpanner
2668 #'(bound-details right text) = #"hhh"
2669 c4^\startTextSpan c c c \stopTextSpan
2672 Note that negative values move the text @emph{up}, contrary to the
2673 effect that might be expected, as a value of @w{@code{-1}} or
2674 @code{DOWN} means align the @emph{bottom} edge of the text with
2675 the spanner line. A value of @code{1} or @code{UP} aligns
2676 the top edge of the text with the spanner line.
2679 Setting this sub-property to @code{#t} produces an arrowhead at the
2683 This sub-property controls the space between the specified
2684 end point of the line and the actual end. Without padding, a
2685 glissando would start and end in the center of each note head.
2689 The music function @code{\endSpanners} terminates the spanner
2690 which starts on the immediately following note prematurely. It
2691 is terminated after exactly one note, or at the following bar line
2692 if @code{to-barline} is true and a bar line occurs before the next
2695 @lilypond[verbatim,quote,ragged-right,relative=2]
2697 c2 \startTextSpan c2 c2
2702 When using @code{\endSpanners} it is not necessary to close
2703 \startTextSpan with \stopTextSpan, nor is it necessary to close
2704 hairpins with @code{\!}.
2707 Internals Reference:
2708 @rinternals{TextSpanner},
2709 @rinternals{Glissando},
2710 @rinternals{VoiceFollower},
2711 @rinternals{TrillSpanner},
2712 @rinternals{line-spanner-interface}.
2715 @node Visibility of objects
2716 @subsection Visibility of objects
2718 @cindex objects, visibility of
2719 @cindex grobs, visibility of
2720 @cindex visibility of objects
2722 There are four main ways in which the visibility of layout objects
2723 can be controlled: their stencil can be removed, they can be made
2724 transparent, they can be colored white, or their
2725 @code{break-visibility} property can be overridden. The first
2726 three apply to all layout objects; the last to just a few -- the
2727 @emph{breakable} objects. The Learning Manual introduces these
2728 four techniques, see @rlearning{Visibility and color of objects}.
2730 There are also a few other techniques which are specific to
2731 certain layout objects. These are covered under Special
2735 * Removing the stencil::
2736 * Making objects transparent::
2737 * Painting objects white::
2738 * Using break-visibility::
2739 * Special considerations::
2743 @node Removing the stencil
2744 @unnumberedsubsubsec Removing the stencil
2746 @cindex stencil, removing
2748 Every layout object has a stencil property. By default this is set
2749 to the specific function which draws that object. If this property
2750 is overridden to @code{#f} no function will be called and the object
2751 will not be drawn. The default action can be recovered with
2754 @lilypond[quote,verbatim,relative=1]
2756 \override Score.BarLine #'stencil = ##f
2758 \revert Score.BarLine #'stencil
2762 @node Making objects transparent
2763 @unnumberedsubsubsec Making objects transparent
2765 @cindex transparent, making objects
2767 Every layout object has a transparent property which by default is
2768 set to @code{#f}. If set to @code{#t} the object still occupies
2769 space but is made invisible.
2771 @lilypond[quote,verbatim,relative=2]
2773 \once \override NoteHead #'transparent = ##t
2777 @node Painting objects white
2778 @unnumberedsubsubsec Painting objects white
2780 @cindex objects, coloring
2781 @cindex coloring objects
2783 @cindex printing order
2784 @cindex overwriting objects
2785 @cindex objects, overwriting
2786 @cindex grobs, overwriting
2788 Every layout object has a color property which by default is set
2789 to @code{black}. If this is overridden to @code{white} the object
2790 will be indistinguishable from the white background. However,
2791 if the object crosses other objects the color of the crossing
2792 points will be determined by the order in which they are drawn,
2793 and this may leave a ghostly image of the white object, as shown
2796 @lilypond[quote,verbatim,relative=2]
2797 \override Staff.Clef #'color = #white
2801 This may be avoided by changing the order of printing the objects.
2802 All layout objects have a @code{layer} property which should be set
2803 to an integer. Objects with the lowest value of @code{layer} are
2804 drawn first, then objects with progressively higher values are drawn,
2805 so objects with higher values overwrite objects with lower values.
2806 By default most objects are assigned a @code{layer} value of
2807 @code{1}, although a few objects, including @code{StaffSymbol} and
2808 @code{BarLine}, are assigned a value of @code{0}. The order of
2809 printing objects with the same value of @code{layer} is indeterminate.
2811 In the example above the white clef, with a default @code{layer}
2812 value of @code{1}, is drawn after the staff lines (default
2813 @code{layer} value @code{0}), so overwriting them. To change this,
2814 the @code{Clef} object must be given in a lower value of
2815 @code{layer}, say @w{@code{-1}}, so that it is drawn earlier:
2817 @lilypond[quote,verbatim,relative=2]
2818 \override Staff.Clef #'color = #white
2819 \override Staff.Clef #'layer = #-1
2823 @node Using break-visibility
2824 @unnumberedsubsubsec Using break-visibility
2826 @c TODO Add making other objects breakable
2828 @cindex break-visibility
2830 Most layout objects are printed only once, but some like
2831 bar lines, clefs, time signatures and key signatures, may need
2832 to be printed twice when a line break occurs -- once at the end
2833 of the line and again at the start of the next line. Such
2834 objects are called @emph{breakable}, and have a property, the
2835 @code{break-visibility} property to control their visibility
2836 at the three positions in which they may appear -- at the
2837 start of a line, within a line if they are changed, and at the
2838 end of a line if a change takes place there.
2840 For example, the time signature
2841 by default will be printed at the start of the first line, but
2842 nowhere else unless it changes, when it will be printed at the
2843 point at which the change occurs. If this change occurs at the
2844 end of a line the new time signature will be printed at the start
2845 of the next line and a cautionary time signature will be printed
2846 at the end of the previous line as well.
2848 This behaviour is controlled by the @code{break-visibility}
2849 property, which is explained in
2850 @c Leave this ref on a newline - formats incorrectly otherwise -td
2851 @rlearning{Visibility and color of objects}. This property takes
2852 a vector of three booleans which, in order, determine whether the
2853 object is printed at the end of, within the body of, or at the
2854 beginning of a line. Or to be more precise, before a line break,
2855 where there is no line break, or after a line break.
2857 Alternatively, these eight combinations may be specified
2858 by pre-defined functions, defined in @file{scm/output-lib.scm},
2859 where the last three columns indicate whether the layout objects
2860 will be visible in the positions shown at the head of the columns:
2862 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2863 @headitem Function @tab Vector @tab Before @tab At no @tab After
2864 @headitem form @tab form @tab break @tab break @tab break
2866 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2867 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2868 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2869 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2870 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2871 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2872 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2873 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2876 The default settings of @code{break-visibility} depend on the
2877 layout object. The following table shows all the layout objects
2878 of interest which are affected by @code{break-visibility} and the
2879 default setting of this property:
2881 @multitable @columnfractions .3 .3 .4
2883 @headitem Layout object @tab Usual context @tab Default setting
2885 @c omit Ambitus as it appears not to be affected by break-visibility -td
2886 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2887 @item @code{BarLine} @tab @code{Score} @tab calculated
2888 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2889 @c omit the following item until it can be explained -td
2890 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2891 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2892 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2893 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2894 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2895 @c omit KeyCancellation until it can be explained -td
2896 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2897 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2898 @c omit LeftEdge until it can be explained -td
2899 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2900 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2901 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2902 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2906 The example below shows the use of the vector form to control the
2907 visibility of bar lines:
2909 @lilypond[quote,verbatim,relative=1,ragged-right]
2912 % Remove bar line at the end of the current line
2913 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2919 Although all three components of the vector used to override
2920 @code{break-visibility} must be present, not all of them are
2921 effective with every layout object, and some combinations may
2922 even give errors. The following limitations apply:
2925 @item Bar lines cannot be printed at start of line.
2926 @item A bar number cannot be printed at the start of the first
2927 line unless it is set to be different from 1.
2928 @item Clef -- see below
2929 @item Double percent repeats are either all printed or all
2930 suppressed. Use begin-of line-invisible to print and
2931 all-invisible to suppress.
2932 @item Key signature -- see below
2933 @item OctavateEight -- see below
2936 @node Special considerations
2937 @unnumberedsubsubsec Special considerations
2939 @strong{@emph{Visibility following explicit changes}}
2941 @cindex key signature, visibility following explicit change
2942 @cindex explicitKeySignatureVisibility
2943 @cindex clef, visibility following explicit change
2944 @cindex explicitClefVisibility
2946 The @code{break-visibility} property controls the visibility of
2947 key signatures and changes of clef only at the start of lines,
2948 i.e. after a break. It has no effect on the visibility of the
2949 key signature or clef following an explicit key change or an
2950 explicit clef change within or at the end of a line. In the
2951 following example the key signature following the explicit change
2952 to B-flat major is still visible, even though @code{all-invisible}
2955 @lilypond[quote,verbatim,relative=1,ragged-right]
2958 % Try to remove all key signatures
2959 \override Staff.KeySignature #'break-visibility = #all-invisible
2967 The visibility of such explicit key signature and clef changes is
2968 controlled by the @code{explicitKeySignatureVisibility} and
2969 @code{explicitClefVisibility} properties. These are the equivalent
2970 of the @code{break-visibility} property and both take a vector of
2971 three booleans or the predefined functions listed above, exactly like
2972 @code{break-visibility}. Both are properties of the Staff context,
2973 not the layout objects themselves, and so they are set using the
2974 @code{\set} command. Both are set by default to @code{all-visible}.
2975 These properties control only the visibility of key signatures and
2976 clefs resulting from explicit changes and do not affect key
2977 signatures and clefs at the beginning of lines;
2978 @code{break-visibility} must still be overridden in the appropriate
2979 object to remove these.
2981 @lilypond[quote,verbatim,relative=1,ragged-right]
2984 \set Staff.explicitKeySignatureVisibility = #all-invisible
2985 \override Staff.KeySignature #'break-visibility = #all-invisible
2992 @strong{@emph{Visibility of cautionary accidentals}}
2994 To remove the cautionary accidentals printed at an explicit key
2995 change, set the Staff context property @code{printKeyCancellation}
2998 @lilypond[quote,verbatim,relative=1,ragged-right]
3001 \set Staff.explicitKeySignatureVisibility = #all-invisible
3002 \set Staff.printKeyCancellation = ##f
3003 \override Staff.KeySignature #'break-visibility = #all-invisible
3010 With these overrides only the accidentals before the notes remain
3011 to indicate the change of key.
3013 @c TODO Add visibility of cautionary accidentals before notes
3015 @strong{@emph{Automatic bars}}
3017 @cindex automaticBars
3018 @cindex bar lines, suppressing
3020 As a special case, the printing of bar lines can also be turned off
3021 by setting the @code{automaticBars} property in the Score context.
3022 If set to @code{#f}, bar lines will not be printed automatically;
3023 they must be explicitly created with a @code{\bar} command. Unlike
3024 the @code{\cadenzaOn} predefined command, measures are still counted.
3025 Bar generation will resume according to that count if this property
3026 is later set to @code{#t}. When set to @code{#f}, line breaks can
3027 occur only at explicit @code{\bar} commands.
3031 @strong{@emph{Octavated clefs}}
3033 @cindex octavated clefs, visibility of
3034 @cindex visibility of octavated clefs
3035 @cindex clefs, visibility of octavation
3037 The small octavation symbol on octavated clefs is produced by the
3038 @code{OctavateEight} layout object. Its visibility is automatically
3039 inherited from the @code{Clef} object, so it is not necessary to apply
3040 any required @code{break-visibility} overrides to the @code{OctavateEight}
3041 layout objects to suppress octavation symbols for invisible clefs.
3043 For explicit clef changes, the @code{explicitClefVisibility}
3044 property controls both the clef symbol and any octavation symbol
3049 @rlearning{Visibility and color of objects}.
3053 @subsection Line styles
3055 Some performance indications, e.g., @i{rallentando} and
3056 @i{accelerando} and @i{trills} are written as text and are
3057 extended over many measures with lines, sometimes dotted or wavy.
3059 These all use the same routines as the glissando for drawing the
3060 texts and the lines, and tuning their behavior is therefore also
3061 done in the same way. It is done with a spanner, and the routine
3062 responsible for drawing the spanners is
3063 @code{ly:line-interface::print}. This routine determines the
3064 exact location of the two @i{span points} and draws a line
3065 between them, in the style requested.
3067 Here is an example showing the different line styles available,
3068 and how to tune them.
3070 @lilypond[relative=2,ragged-right,verbatim,quote]
3072 \once \override Glissando #'style = #'dashed-line
3074 \override Glissando #'style = #'dotted-line
3076 \override Glissando #'style = #'zigzag
3078 \override Glissando #'style = #'trill
3082 The locations of the end-points of the spanner are computed
3083 on-the-fly for every graphic object, but it is possible to
3087 @lilypond[relative=2,ragged-right,verbatim,quote]
3089 \once \override Glissando #'(bound-details right Y) = #-2
3093 The value for @code{Y} is set to @w{@code{-2}} for the right end
3094 point. The left side may be similarly adjusted by specifying
3095 @code{left} instead of @code{right}.
3097 If @code{Y} is not set, the value is computed from the vertical
3098 position of the left and right attachment points of the spanner.
3100 Other adjustments of spanners are possible, for details, see
3103 @node Rotating objects
3104 @subsection Rotating objects
3106 Both layout objects and elements of markup text can be rotated by
3107 any angle about any point, but the method of doing so differs.
3110 * Rotating layout objects::
3114 @node Rotating layout objects
3115 @unnumberedsubsubsec Rotating layout objects
3117 @cindex rotating objects
3118 @cindex objects, rotating
3120 All layout objects which support the @code{grob-interface} can be
3121 rotated by setting their @code{rotation} property. This takes a
3122 list of three items: the angle of rotation counter-clockwise,
3123 and the x and y coordinates of the point relative to the object's
3124 reference point about which the rotation is to be performed. The
3125 angle of rotation is specified in degrees and the coordinates in
3128 The angle of rotation and the coordinates of the rotation point must
3129 be determined by trial and error.
3131 @cindex hairpins, angled
3132 @cindex angled hairpins
3134 There are only a few situations where the rotation of layout
3135 objects is useful; the following example shows one situation where
3138 @lilypond[quote,verbatim,relative=1]
3140 \override Hairpin #'rotation = #'(20 -1 0)
3144 @node Rotating markup
3145 @unnumberedsubsubsec Rotating markup
3147 All markup text can be rotated to lie at any angle by prefixing it
3148 with the @code{\rotate} command. The command takes two arguments:
3149 the angle of rotation in degrees counter-clockwise and the text to
3150 be rotated. The extents of the text are not rotated: they take
3151 their values from the extremes of the x and y coordinates of the
3152 rotated text. In the following example the
3153 @code{outside-staff-priority} property for text is set to @code{#f}
3154 to disable the automatic collision avoidance, which would push some
3155 of the text too high.
3157 @lilypond[quote,verbatim,relative=1]
3158 \override TextScript #'outside-staff-priority = ##f
3159 g4^\markup { \rotate #30 "a G" }
3160 b^\markup { \rotate #30 "a B" }
3161 des^\markup { \rotate #30 "a D-Flat" }
3162 fis^\markup { \rotate #30 "an F-Sharp" }
3165 @node Advanced tweaks
3166 @section Advanced tweaks
3168 This section discusses various approaches to fine tuning the
3169 appearance of the printed score.
3172 * Aligning objects::
3173 * Vertical grouping of grobs::
3174 * Modifying stencils::
3175 * Modifying shapes::
3176 * Unpure-pure containers::
3181 @rlearning{Tweaking output},
3182 @rlearning{Other sources of information}.
3185 @ref{Explaining the Internals Reference},
3186 @ref{Modifying properties}.
3189 @rextend{Interfaces for programmers}.
3192 @file{scm/define-grobs.scm}.
3195 @rlsr{Tweaks and overrides}.
3197 Internals Reference:
3198 @rinternals{All layout objects}.
3201 @node Aligning objects
3202 @subsection Aligning objects
3204 Graphical objects which support the @code{self-alignment-interface}
3205 and/or the @code{side-position-interface} can be aligned to a previously
3206 placed object in a variety of ways. For a list of these objects, see
3207 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
3209 All graphical objects have a reference point, a horizontal extent and a
3210 vertical extent. The horizontal extent is a pair of numbers
3211 giving the displacements from the reference point of the left and
3212 right edges, displacements to the left being negative. The vertical
3213 extent is a pair of numbers giving the displacement from the reference
3214 point to the bottom and top edges, displacements down being negative.
3216 An object's position on a staff is given by the values of the
3217 @code{X-offset} and @code{Y-offset} properties. The value of
3218 @code{X-offset} gives the displacement from the X coordinate of
3219 the reference point of the parent object, and the value of
3220 @code{Y-offset} gives the displacement from the center line of the
3221 staff. The values of @code{X-offset} and @code{Y-offset} may
3222 be set directly or may be set to be calculated by procedures in order
3223 to achieve alignment with the parent object.
3225 @warning{Many objects have special positioning considerations which
3226 cause any setting of @code{X-offset} or @code{Y-offset} to be
3227 ignored or modified, even though the object supports the
3228 @code{self-alignment-interface}. Overriding the @code{X-offset}
3229 or @code{Y-offset} properties to a fixed value causes the respective
3230 @code{self-alignment} property to be disregarded.}
3232 For example, an accidental can be repositioned vertically by setting
3233 @code{Y-offset} but any changes to @code{X-offset} have no effect.
3235 Rehearsal marks may be aligned with breakable objects such as bar
3236 lines, clef symbols, time signature symbols and key signatures. There
3237 are special properties to be found in the @code{break-aligned-interface}
3238 for positioning rehearsal marks on such objects.
3242 @ref{Using the break-alignable-interface}.
3245 @rextend{Callback functions}.
3248 * Setting X-offset and Y-offset directly::
3249 * Using the side-position-interface::
3250 * Using the self-alignment-interface::
3251 * Using the break-alignable-interface::
3254 @node Setting X-offset and Y-offset directly
3255 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
3257 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
3258 properties of many objects. The following example shows three
3259 notes with the default fingering position and the positions with @code{X-offset}
3260 and @code{Y-offset} modified.
3262 @lilypond[verbatim,quote,relative=2]
3265 -\tweak #'X-offset #0
3266 -\tweak #'Y-offset #0
3269 -\tweak #'X-offset #-1
3270 -\tweak #'Y-offset #1
3276 @node Using the side-position-interface
3277 @unnumberedsubsubsec Using the @code{side-position-interface}
3279 An object which supports the @code{side-position-interface} can be
3280 placed next to its parent object so that
3281 the specified edges of the two objects touch. The object may be
3282 placed above, below, to the right or to the left of the parent.
3283 The parent cannot be specified; it is determined by the order of
3284 elements in the input stream. Most objects have the associated
3285 note head as their parent.
3287 The values of the @code{side-axis} and @code{direction} properties
3288 determine where the object is to be placed, as follows:
3290 @c TODO add an example of each to the table
3292 @multitable @columnfractions .3 .3 .3
3293 @headitem @code{side-axis} @tab @code{direction} @tab
3294 @headitem property @tab property @tab Placement
3296 @item @code{0} @tab @code{-1} @tab left
3297 @item @code{0} @tab @code{1} @tab right
3298 @item @code{1} @tab @code{-1} @tab below
3299 @item @code{1} @tab @code{1} @tab above
3303 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
3304 the procedure @code{ly:side-position-interface::x-aligned-side}.
3305 This procedure will return the correct value of @code{X-offset} to
3306 place the object to the left or right side of the parent according
3307 to value of @code{direction}.
3309 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3310 the procedure @code{ly:side-position-interface::y-aligned-side}.
3311 This procedure will return the correct value of @code{Y-offset} to
3312 place the object to the top or bottom of the parent according
3313 to value of @code{direction}.
3315 @c TODO Add examples
3317 @node Using the self-alignment-interface
3318 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3320 @emph{Self-aligning objects horizontally}
3322 The horizontal alignment of an object which supports the
3323 @code{self-alignment-interface} is controlled by the value of
3324 the @code{self-alignment-X} property, provided the object's
3325 @code{X-offset} property is set to
3326 @code{ly:self-alignment-interface::x-aligned-on-self}.
3327 @code{self-alignment-X} may be given any
3328 real value, in units of half the total X extent of the
3329 object. Negative values move the object to the right, positive
3330 to the left. A value of @code{0} centers the object on the
3331 reference point of its parent, a value of @w{@code{-1}} aligns the
3332 left edge of the object on the reference point of its parent,
3333 and a value of @code{1} aligns the right edge of the object on the
3334 reference point of its parent. The symbols @code{LEFT},
3335 @code{CENTER}, and @code{RIGHT} may be used instead of the values
3336 @w{@code{-1}}, @code{0}, and @code{1}, respectively.
3338 Normally the @code{\override} command would be used to modify the
3339 value of @code{self-alignment-X}, but the @code{\tweak} command
3340 can be used to separately align several annotations on a single
3343 @lilypond[quote,verbatim,relative=1]
3345 -\tweak #'self-alignment-X #-1
3347 -\tweak #'self-alignment-X #0
3349 -\tweak #'self-alignment-X #RIGHT
3351 -\tweak #'self-alignment-X #-2.5
3352 ^"aligned further to the right"
3355 @emph{Self-aligning objects vertically}
3357 Objects may be aligned vertically in an analogous way to aligning
3358 them horizontally if the @code{Y-offset} property is set to
3359 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3360 other mechanisms are often involved in vertical alignment: the
3361 value of @code{Y-offset} is just one variable taken into account.
3362 This may make adjusting the value of some objects tricky.
3363 The units are just half the vertical extent of the object, which
3364 is usually quite small, so quite large numbers may be required.
3365 A value of @w{@code{-1}} aligns the lower edge of the object with
3366 the reference point of the parent object, a value of @code{0}
3367 aligns the center of the object with the reference point of the
3368 parent, and a value of @code{1} aligns the top edge of the object
3369 with the reference point of the parent. The symbols @code{DOWN},
3370 @code{CENTER}, and @code{UP} may be substituted for @w{@code{-1}},
3371 @code{0}, and @code{1}, respectively.
3373 @emph{Self-aligning objects in both directions}
3375 By setting both @code{X-offset} and @code{Y-offset}, an object may
3376 be aligned in both directions simultaneously.
3378 The following example shows how to adjust a fingering mark so
3379 that it nestles close to the note head.
3381 @lilypond[quote,verbatim,relative=2]
3383 -\tweak #'self-alignment-X #0.5 % move horizontally left
3384 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
3385 -\tweak #'self-alignment-Y #-1 % move vertically up
3390 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3392 @c Cannot document as they do not seem to operate consistently on all objects -td
3393 @c TODO investigate further
3395 The @code{aligned-on-parent} procedures are used in the same way
3396 as the @code{aligned-on-self} procedures, they difference being
3397 that they permit an object to be aligned with the @emph{edges} of
3398 the parent rather than the parent's reference point. The following
3399 example shows the difference:
3403 @lilypond[verbatim,quote]
3409 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3411 @c Cannot document as they do not seem to operate consistently on all objects -td
3412 @c TODO investigate further
3416 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3418 @node Using the break-alignable-interface
3419 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3421 @cindex align to objects
3422 @cindex break-align-symbols
3424 Rehearsal marks and bar numbers may be aligned with notation
3425 objects other than bar lines. These objects include @code{ambitus},
3426 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3427 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3428 @code{time-signature}.
3430 By default, rehearsal marks and bar numbers will be horizontally
3431 centered above the object:
3433 @lilypond[verbatim,quote,relative=1]
3434 % The rehearsal mark will be centered above the Clef
3435 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
3440 % The rehearsal mark will be centered above the Time Signature
3441 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
3447 % The rehearsal mark will be centered above the Breath Mark
3448 \override Score.RehearsalMark #'break-align-symbols = #'(breathing-sign)
3457 A list of possible target alignment objects may be specified. If
3458 some of the objects are invisible at that point due to the setting
3459 of @code{break-visibility} or the explicit visibility settings for
3460 keys and clefs, the rehearsal mark or bar number is aligned to the
3461 first object in the list which is visible. If no objects in the
3462 list are visible the object is aligned to the bar line. If the bar
3463 line is invisible the object is aligned to the place where the bar
3466 @lilypond[verbatim,quote,relative=1]
3467 % The rehearsal mark will be centered above the Key Signature
3468 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3473 % The rehearsal mark will be centered above the Clef
3474 \set Staff.explicitKeySignatureVisibility = #all-invisible
3475 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3480 % The rehearsal mark will be centered above the Bar Line
3481 \set Staff.explicitKeySignatureVisibility = #all-invisible
3482 \set Staff.explicitClefVisibility = #all-invisible
3483 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3490 The alignment of the rehearsal mark relative to the notation object
3491 can be changed, as shown in the following example. In a score with
3492 multiple staves, this setting should be done for all the staves.
3494 @lilypond[verbatim,quote,relative=1]
3495 % The RehearsalMark will be centered above the Key Signature
3496 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3502 % The RehearsalMark will be aligned with the left edge of the Key Signature
3503 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3507 % The RehearsalMark will be aligned with the right edge of the Key Signature
3508 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3514 The rehearsal mark can also be offset to the right or left of the left
3515 edge by an arbitrary amount. The units are staff-spaces:
3517 @lilypond[verbatim,quote,relative=1]
3518 % The RehearsalMark will be aligned with the left edge of the Key Signature
3519 % and then shifted right by 3.5 staff-spaces
3520 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3521 \once \override Score.KeySignature #'break-align-anchor = #3.5
3525 % The RehearsalMark will be aligned with the left edge of the Key Signature
3526 % and then shifted left by 2 staff-spaces
3527 \once \override Score.KeySignature #'break-align-anchor = #-2
3534 @node Vertical grouping of grobs
3535 @subsection Vertical grouping of grobs
3537 @c TODO Expand this section
3539 The VerticalAlignment and VerticalAxisGroup grobs work together.
3540 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3541 etc. VerticalAlignment then vertically aligns the different grobs
3542 grouped together by VerticalAxisGroup. There is usually only one
3543 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3547 @node Modifying stencils
3548 @subsection Modifying stencils
3550 All layout objects have a @code{stencil} property which is part of
3551 the @code{grob-interface}. By default, this property is usually
3552 set to a function specific to the object that is tailor-made to
3553 render the symbol which represents it in the output. For example,
3554 the standard setting for the @code{stencil} property of the
3555 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3557 The standard symbol for any object can be replaced by modifying the
3558 @code{stencil} property to reference a different, specially-written,
3559 procedure. This requires a high level of knowledge of the internal
3560 workings of LilyPond, but there is an easier way which can often
3561 produce adequate results.
3563 This is to set the @code{stencil} property to the procedure which
3564 prints text -- @code{ly:text-interface::print} -- and to add a
3565 @code{text} property to the object which is set to contain the
3566 markup text which produces the required symbol. Due to the
3567 flexibility of markup, much can be achieved -- see in particular
3568 @ref{Graphic notation inside markup}.
3570 The following example demonstrates this by changing the note head
3571 symbol to a cross within a circle.
3573 @lilypond[verbatim,quote]
3575 \once \override NoteHead #'stencil = #ly:text-interface::print
3576 \once \override NoteHead #'text = \markup {
3578 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3579 \musicglyph #"noteheads.s2cross"
3587 Any of the glyphs in the feta Font can be supplied to the
3588 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3590 @c TODO Add inserting eps files or ref to later
3592 @c TODO Add inserting Postscript or ref to later
3596 @ref{Graphic notation inside markup},
3597 @ref{Formatting text},
3598 @ref{Text markup commands},
3599 @ref{The Feta font}.
3602 @node Modifying shapes
3603 @subsection Modifying shapes
3606 * Modifying ties and slurs::
3609 @node Modifying ties and slurs
3610 @unnumberedsubsubsec Modifying ties and slurs
3612 @cindex slurs, modifying
3613 @cindex ties, modifying
3614 @cindex Bézier curves, control points
3615 @cindex control points, Bézier curves
3617 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3618 curves. If the shape of the tie or slur which is calculated
3619 automatically is not optimum, the shape may be modified manually by
3620 explicitly specifying the four control points required to define
3621 a third-order Bézier curve.
3623 Third-order or cubic Bézier curves are defined by four control
3624 points. The first and fourth control points are precisely the
3625 starting and ending points of the curve. The intermediate two
3626 control points define the shape. Animations showing how the curve
3627 is drawn can be found on the web, but the following description
3628 may be helpful. The curve starts from the first control point
3629 heading directly towards the second, gradually bending over to
3630 head towards the third and continuing to bend over to head towards
3631 the fourth, arriving there travelling directly from the third
3632 control point. The curve is entirely contained in the
3633 quadrilateral defined by the four control points.
3635 Here is an example of a case where the tie is not optimum, and
3636 where @code{\tieDown} would not help.
3638 @lilypond[verbatim,quote,relative=1]
3642 { r4 <g c,> <g c,> <g c,> }
3646 One way of improving this tie is to manually modify its control
3649 The coordinates of the Bézier control points are specified in units
3650 of staff-spaces. The X@tie{}coordinate is relative to the reference
3651 point of the note to which the tie or slur is attached, and the
3652 Y@tie{}coordinate is relative to the staff center line. The
3653 coordinates are entered as a list of four pairs of decimal numbers
3654 (reals). One approach is to estimate the coordinates of the two
3655 end points, and then guess the two intermediate points. The optimum
3656 values are then found by trial and error.
3658 It is useful to remember that a symmetric curve requires symmetric
3659 control points, and that Bézier curves have the useful property that
3660 transformations of the curve such as translation, rotation and
3661 scaling can be achieved by applying the same transformation to the
3662 curve's control points.
3664 For the example above the following override gives a satisfactory
3665 tie. Note the placement -- it has to be immediately before the note
3666 to which the start of the tie (or slur) is attached.
3668 @lilypond[verbatim,quote,relative=1]
3672 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3676 { r4 <g c,> <g c,> <g c,> }
3681 It is not possible to modify shapes of ties or slurs by changing
3682 the @code{control-points} property if there are multiple ties or slurs
3683 at the same musical moment -- the @code{\tweak} command will also not
3684 work in this case. However, the @code{tie-configuration} property of
3685 @code{TieColumn} can be overridden to set start line and direction as
3689 Internals Reference:
3690 @rinternals{TieColumn}.
3692 @cindex Scheme, pure containers
3693 @cindex Scheme, unpure containers
3694 @cindex pure containers, Scheme
3695 @cindex unpure containers, Scheme
3696 @cindex horizontal spacing, overriding
3699 @node Unpure-pure containers
3700 @subsection Unpure-pure containers
3702 Unpure-pure containers are useful for overriding @emph{Y-axis} spacing
3703 calculations - specifically @code{Y-offset} and @code{Y-extent} - with a
3704 Scheme function instead of a literal (i.e. a number or pair).
3706 For certain grobs, the @code{Y-extent} is based on the @code{stencil}
3707 property, overriding the stencil property of one of these will
3708 require an additional @code{Y-extent} override with an unpure-pure
3709 container. When a function overrides a @code{Y-offset} and/or
3710 @code{Y-extent} it is assumed that this will trigger line breaking
3711 calculations too early during compilation. So the function is not
3712 evaluated at all (usually returning a value of @samp{0} or
3713 @samp{'(0 . 0)}) which can result in collisions. A @q{pure} function
3714 will not affect properties, objects or grob suicides and therefore will
3715 always have its Y-axis-related evaluated correctly.
3717 Currently, there are about thirty functions that are already considered
3718 @q{pure} and Unpure-pure containers are a way to set functions not on
3719 this list as @q{pure}. The @q{pure} function is evaluated @emph{before}
3720 any line-breaking and so the horizontal spacing can be adjusted
3721 @q{in time}. The @q{unpure} function is then evaluated @emph{after}
3724 @warning{As it is difficult to always know which functions are on this
3725 list we recommend that any @q{pure} functions you create do not use
3726 @code{Beam} or @code{VerticalAlignment} grobs.}
3728 An unpure-pure container is constructed as follows;
3730 @code{(ly:make-unpure-pure-container f0 f1)}
3732 where @code{f0} is a function taking @var{n} arguments (@var{n >= 1})
3733 and the first argument must always be the grob. This is the function
3734 that gives the actual result. @var{f1} is the function being labeled
3735 as @q{pure} that takes @var{n + 2} arguments. Again, the first argument
3736 must always still be the grob but the second and third are @q{start}
3737 and @q{end} arguments.
3739 @var{start} and @var{end} are, for all intents and purposes, dummy
3740 values that only matter for @code{Spanners} (i.e @code{Hairpin} or
3741 @code{Beam}), that can return different height estimations based on a
3742 starting and ending column.
3744 The rest are the other arguments to the first function (which
3745 may be none if @var{n = 1}).
3747 The results of the second function are used as an approximation of the
3748 value needed which is then used by the first function to get the real
3749 value which is then used for fine-tuning much later during the spacing
3752 @lilypond[verbatim,quote,ragged-right]
3753 #(define (square-line-circle-space grob)
3754 (let* ((pitch (ly:event-property (ly:grob-property grob 'cause) 'pitch))
3755 (notename (ly:pitch-notename pitch)))
3756 (if (= 0 (modulo notename 2))
3757 (make-circle-stencil 0.5 0.0 #t)
3758 (make-filled-box-stencil '(0 . 1.0)
3761 squareLineCircleSpace = {
3762 \override NoteHead #'stencil = #square-line-circle-space
3765 smartSquareLineCircleSpace = {
3766 \squareLineCircleSpace
3767 \override NoteHead #'Y-extent =
3768 #(ly:make-unpure-pure-container
3769 ly:grob::stencil-height
3770 (lambda (grob start end) (ly:grob::stencil-height grob)))
3773 \new Voice \with { \remove "Stem_engraver" }
3775 \squareLineCircleSpace
3777 \smartSquareLineCircleSpace
3782 In the first measure, without the unpure-pure container, the spacing
3783 engine does not know the width of the note head and lets it collide with
3784 the accidentals. In the second measure, with unpure-pure containers,
3785 the spacing engine knows the width of the note heads and avoids the
3786 collision by lengthening the line accordingly.
3788 Usually for simple calculations nearly-identical functions for both the
3789 @q{unpure} and @q{pure} parts can be used, by only changing the number
3790 of arguments passed to, and the scope of, the function.
3792 @warning{If a function is labeled as @q{pure} and it turns out not to
3793 be, the results can be unexpected.}
3796 @node Using music functions
3797 @section Using music functions
3799 @c TODO -- add @seealso, etc. to these subsections
3801 Where tweaks need to be reused with different music expressions,
3802 it is often convenient to make the tweak part of a @emph{music
3803 function}. In this section, we discuss only @emph{substitution}
3804 functions, where the object is to substitute a variable into a
3805 piece of LilyPond input code. Other more complex functions are
3806 described in @rextend{Music functions}.
3809 * Substitution function syntax::
3810 * Substitution function examples::
3813 @node Substitution function syntax
3814 @subsection Substitution function syntax
3816 Making a function that substitutes a variable into LilyPond
3817 code is easy. The general form of these functions is
3821 #(define-music-function
3822 (parser location @var{arg1} @var{arg2} @dots{})
3823 (@var{type1?} @var{type2?} @dots{})
3825 @var{@dots{}music@dots{}}
3832 @multitable @columnfractions .33 .66
3833 @item @code{@var{argN}}
3834 @tab @var{n}th argument
3836 @item @code{@var{typeN?}}
3837 @tab a scheme @emph{type predicate} for which @code{@var{argN}}
3838 must return @code{#t}.
3840 @item @code{@var{@dots{}music@dots{}}}
3841 @tab normal LilyPond input, using @code{$} (in places where only
3842 Lilypond constructs are allowed) or @code{#} (to use it as a Scheme
3843 value or music function argument) to reference arguments
3847 The @code{parser} and @code{location} arguments are mandatory, and
3848 are used in some advanced situations as described in the
3849 @q{Extending} manual (see @rextend{Music functions}). For
3850 substitution functions, just be sure to include them.
3852 The list of type predicates is also required. Some of the most
3853 common type predicates used in music functions are:
3857 cheap-list? @emph{(use instead of }@q{list?}@emph{ for faster processing)}
3869 For a list of available type predicates, see
3870 @ref{Predefined type predicates}. User-defined type predicates
3875 @ref{Predefined type predicates}.
3878 @rextend{Music functions}.
3881 @file{lily/music-scheme.cc},
3883 @file{scm/lily.scm}.
3886 @node Substitution function examples
3887 @subsection Substitution function examples
3889 This section introduces some substitution function examples.
3890 These are not intended to be exhaustive, but rather to demonstrate
3891 some of the possibilities of simple substitution functions.
3893 In the first example, a function is defined that simplifies
3894 setting the padding of a TextScript:
3896 @lilypond[quote,verbatim,ragged-right]
3898 #(define-music-function
3899 (parser location padding)
3902 \once \override TextScript #'padding = #padding
3906 c4^"piu mosso" b a b
3908 c4^"piu mosso" d e f
3910 c4^"piu mosso" fis a g
3914 In addition to numbers, we can use music expressions such
3915 as notes for arguments to music functions:
3917 @c TODO: use a better example (the music argument is redundant).
3919 @lilypond[quote,verbatim,ragged-right]
3921 #(define-music-function
3922 (parser location note)
3925 \once \override Voice.NoteHead #'stencil =
3926 #ly:text-interface::print
3927 \once \override Voice.NoteHead #'text =
3928 \markup \musicglyph #"custodes.mensural.u0"
3929 \once \override Voice.Stem #'stencil = ##f
3933 \relative c' { c4 d e f \custosNote g }
3936 Substitution functions with multiple arguments can be defined:
3938 @lilypond[quote,verbatim,ragged-right]
3940 #(define-music-function
3941 (parser location padding tempotext)
3944 \once \override Score.MetronomeMark #'padding = #padding
3945 \tempo \markup { \bold #tempotext }
3949 \tempo \markup { "Low tempo" }
3951 \tempoPadded #4.0 #"High tempo"
3956 @c TODO: add appropriate @@ref's here.