1 @c -*- coding: utf-8; mode: texinfo; -*-
4 Translation of GIT committish: FILL-IN-HEAD-COMMITTISH
6 When revising a translation, copy the HEAD committish of the
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12 @node Changing defaults
13 @chapter Changing defaults
15 The purpose of LilyPond's design is to provide the finest quality
16 output by default. Nevertheless, it may happen that you need to
17 change this default layout. The layout is controlled through a large
18 number of @q{knobs and switches} collectively called @q{properties}.
19 A tutorial introduction to accessing and modifying these properties
20 can be found in the Learning Manual, see @rlearning{Tweaking output}.
21 This should be read first. This chapter covers similar ground, but
22 in a style more appropriate to a reference manual.
24 @cindex Internals Reference
26 The definitive description of the controls available for tuning can
27 be found in a separate document: @rinternalsnamed{Top,the Internals
28 Reference}. That manual lists all the variables, functions and
29 options available in LilyPond. It is written as a HTML document,
31 @c leave the @uref as one long line.
32 @uref{http://@/lilypond@/.org/@/doc/@/stable/@/Documentation/@/user/@/lilypond@/-internals/,on@/-line},
33 and is also included with the LilyPond documentation package.
35 Internally, LilyPond uses Scheme (a LISP dialect) to provide
36 infrastructure. Overriding layout decisions in effect accesses the
37 program internals, which requires Scheme input. Scheme elements are
38 introduced in a @code{.ly} file with the hash mark
39 @code{#}.@footnote{@rextend{Scheme tutorial}, contains a short tutorial
40 on entering numbers, lists, strings, and symbols in Scheme.}
44 * Interpretation contexts::
45 * Explaining the Internals Reference::
46 * Modifying properties::
47 * Useful concepts and properties::
52 @node Interpretation contexts
53 @section Interpretation contexts
55 This section describes what contexts are, and how to modify them.
58 * Contexts explained::
60 * Keeping contexts alive::
61 * Modifying context plug-ins::
62 * Changing context default settings::
63 * Defining new contexts::
70 @rlearning{Contexts and engravers}.
73 @file{ly/@/engraver@/-init@/.ly},
74 @file{ly/@/performer@/-init@/.ly}.
77 @rlsr{Contexts and engravers}.
80 @rinternals{Contexts},
81 @rinternals{Engravers and Performers}.
84 @node Contexts explained
85 @subsection Contexts explained
88 @c TODO Rethink and rewrite
90 >> > > - list of contexts: my *danger unmaintainable*
91 >> > > alarm just went off. I'm
93 I knew it would... And leaving out some of them is perfectly fine
95 I do think that a list like this, with the main contexts and a
97 description of what they do (perhaps also with a note about what
99 behavior is associated with each of them, but this may be
101 should be there, and then we could simply list the remaining ones
103 further explanation and with links to the IR.
106 @c TODO Improve layout, order and consistency of wording -td
108 @c TODO Add introduction which explains contexts in generality -td
110 @c TODO Describe propagation of property values -td
112 Contexts are arranged hierarchically:
115 * Score - the master of all contexts::
116 * Top-level contexts - staff containers::
117 * Intermediate-level contexts - staves::
118 * Bottom-level contexts - voices::
121 @node Score - the master of all contexts
122 @unnumberedsubsubsec Score - the master of all contexts
124 This is the top level notation context. No other context can
125 contain a Score context. By default the Score context handles
126 the administration of time signatures and makes sure that items
127 such as clefs, time signatures, and key-signatures are aligned
130 A Score context is instantiated implicitly when a
131 @code{\score @{@dots{}@}} or @code{\layout @{@dots{}@}} block is
132 processed, or explicitly when a @code{\new Score} command is
135 @node Top-level contexts - staff containers
136 @unnumberedsubsubsec Top-level contexts - staff containers
138 @strong{@emph{StaffGroup}}
140 Groups staves while adding a bracket on the left side, grouping
141 the staves together. The bar lines of the contained staves are
142 connected vertically. @code{StaffGroup} only consists of a collection
143 of staves, with a bracket in front and spanning bar lines.
145 @strong{@emph{ChoirStaff}}
147 Identical to @code{StaffGroup} except that the bar lines of the
148 contained staves are not connected vertically.
150 @strong{@emph{GrandStaff}}
152 A group of staves, with a brace on the left side, grouping the
153 staves together. The bar lines of the contained staves are
154 connected vertically.
156 @strong{@emph{PianoStaff}}
158 Just like @code{GrandStaff}, but with support for instrument names
159 to the left of each system.
161 @node Intermediate-level contexts - staves
162 @unnumberedsubsubsec Intermediate-level contexts - staves
164 @strong{@emph{Staff}}
166 Handles clefs, bar lines, keys, accidentals. It can contain
167 @code{Voice} contexts.
169 @strong{@emph{RhythmicStaff}}
171 Like @code{Staff} but for printing rhythms. Pitches are ignored;
172 the notes are printed on one line.
174 @strong{@emph{TabStaff}}
176 Context for generating tablature. By default lays the music
177 expression out as a guitar tablature, printed on six lines.
179 @strong{@emph{DrumStaff}}
181 Handles typesetting for percussion. Can contain @code{DrumVoice}
183 @strong{@emph{VaticanaStaff}}
185 Same as @code{Staff}, except that it is designed for typesetting
186 a piece in gregorian style.
188 @strong{@emph{MensuralStaff}}
190 Same as @code{Staff}, except that it is designed for typesetting
191 a piece in mensural style.
193 @node Bottom-level contexts - voices
194 @unnumberedsubsubsec Bottom-level contexts - voices
196 Voice-level contexts initialise certain properties and start
197 appropriate engravers. Being bottom-level contexts, they cannot
198 contain other contexts.
200 @strong{@emph{Voice}}
202 Corresponds to a voice on a staff. This context handles the
203 conversion of dynamic signs, stems, beams, super- and sub-scripts,
204 slurs, ties, and rests. You have to instantiate this explicitly
205 if you require multiple voices on the same staff.
207 @strong{@emph{VaticanaVoice}}
209 Same as @code{Voice}, except that it is designed for typesetting
210 a piece in gregorian style.
212 @strong{@emph{MensuralVoice}}
214 Same as @code{Voice}, with modifications for typesetting a piece in
217 @strong{@emph{Lyrics}}
219 Corresponds to a voice with lyrics. Handles the printing of a
220 single line of lyrics.
222 @strong{@emph{DrumVoice}}
224 The voice context used in a percussion staff.
226 @strong{@emph{FiguredBass}}
228 The context in which @code{BassFigure} objects are created from
229 input entered in @code{\figuremode} mode.
231 @strong{@emph{TabVoice}}
233 The voice context used within a @code{TabStaff} context. Usually
234 left to be created implicitly.
236 @strong{@emph{CueVoice}}
238 A voice context used to render notes of a reduced size, intended
239 primarily for adding cue notes to a staff, see @ref{Formatting
240 cue notes}. Usually left to be created implicitly.
242 @strong{@emph{ChordNames}}
244 Typesets chord names.
249 Then the following, which I don't know what to do with:
251 * GregorianTranscriptionVoice
252 * GregorianTranscriptionStaff
255 Engraves fretboards from chords. Not easy... Not
257 There is now some documentation on FretBoards in the NR, under
258 instrument-specific notation -- cds.
263 Hard coded entry point for LilyPond. Cannot be tuned.
265 Silently discards all musical information given to this
270 @node Creating contexts
271 @subsection Creating contexts
273 @c TODO \new Score and \score
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,fragment]
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
569 they also contain plug-ins called @q{engravers} that create notation
570 elements. For example, the @code{Voice} context contains a
571 @code{Note_head_engraver} and the @code{Staff} context contains a
572 @code{Key_signature_engraver}.
574 For a full a description of each plug-in, see
576 @rinternals{Engravers and Performers}.
579 Internals Reference @expansion{} Translation @expansion{} Engravers.
581 Every context described in
583 @rinternals{Contexts}
586 Internals Reference @expansion{} Translation @expansion{} Context.
588 lists the engravers used for that context.
591 It can be useful to shuffle around these plug-ins. This is done by
592 starting a new context with @code{\new} or @code{\context}, and
598 \new @var{context} \with @{
611 where the @dots{} should be the name of an engraver. Here is a simple
612 example which removes @code{Time_signature_engraver} and
613 @code{Clef_engraver} from a @code{Staff} context,
615 @lilypond[quote,relative=1,verbatim,fragment]
621 \remove "Time_signature_engraver"
622 \remove "Clef_engraver"
629 In the second staff there are no time signature or clef symbols. This
630 is a rather crude method of making objects disappear since it will affect
631 the entire staff. This method also influences the spacing, which may or
632 may not be desirable. More sophisticated methods of blanking objects
633 are shown in @rlearning{Visibility and color of objects}.
635 The next example shows a practical application. Bar lines and time
636 signatures are normally synchronized across the score. This is done
637 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
638 This plug-in keeps an administration of time signature, location
639 within the measure, etc. By moving these engraver from @code{Score} to
640 @code{Staff} context, we can have a score where each staff has its own
643 @cindex polymetric scores
644 @cindex Time signatures, multiple
646 @lilypond[quote,relative=1,ragged-right,verbatim,fragment]
648 \remove "Timing_translator"
649 \remove "Default_bar_line_engraver"
652 \consists "Timing_translator"
653 \consists "Default_bar_line_engraver"
659 \consists "Timing_translator"
660 \consists "Default_bar_line_engraver"
670 Usually the order in which the engravers are specified
671 does not matter, but in a few special cases the order
672 is important, for example where one engraver writes
673 a property and another reads it, or where one engraver
674 creates a grob and another must process it. The order in
675 which the engravers are specified is the order in which
676 they are called to carry out their processing.
678 The following orderings are important: the
679 @code{Bar_engraver} must normally be first, and
680 the @code{New_fingering_engraver} must come before
681 the @code{Script_column_engraver}. There may be others
682 with ordering dependencies.
684 @node Changing context default settings
685 @subsection Changing context default settings
687 The context settings which are to be used by default in
688 @code{Score}, @code{Staff} and @code{Voice} contexts may be specified
689 in a @code{\layout} block, as illustrated in the following example.
690 The @code{\layout} block should be placed within the @code{\score}
691 block to which it is to apply, but outside any music.
693 Note that the @code{\set} command itself and the context must be
694 omitted when the context default values are specified in this way:
696 @lilypond[quote,verbatim]
699 a4^"Really small, thicker stems, no time signature" a a a
706 \override Stem #'thickness = #4.0
707 \remove "Time_signature_engraver"
713 In this example, the @code{\Staff} command specifies that the
714 subsequent specifications are to be applied to all staves within
717 Modifications can be made to the @code{Score} context or all
718 @code{Voice} contexts in a similar way.
722 It is not possible to collect context changes in a variable and apply
723 them to a @code{\context} definition by referring to that variable.
725 The @code{\RemoveEmptyStaffContext} will overwrite your current
726 @code{\Staff} settings. If you wish to change the defaults for a
727 staff which uses @code{\RemoveEmptyStaffContext}, you must do so
728 after calling @code{\RemoveEmptyStaffContext}, ie
733 \RemoveEmptyStaffContext
735 \override Stem #'thickness = #4.0
740 @c TODO: add \with in here.
744 @node Defining new contexts
745 @subsection Defining new contexts
747 @cindex contexts, defining new
748 @cindex engravers, including in contexts
763 Specific contexts, like @code{Staff} and @code{Voice}, are made of
764 simple building blocks. It is possible to create new types of
765 contexts with different combinations of engraver plug-ins.
767 The next example shows how to build a different type of
768 @code{Voice} context from scratch. It will be similar to
769 @code{Voice}, but only prints centered slash note heads. It can be used
770 to indicate improvisation in jazz pieces,
772 @lilypond[quote,ragged-right]
775 \type "Engraver_group"
776 \consists "Note_heads_engraver"
777 \consists "Rhythmic_column_engraver"
778 \consists "Text_engraver"
779 \consists Pitch_squash_engraver
780 squashedPosition = #0
781 \override NoteHead #'style = #'slash
782 \override Stem #'transparent = ##t
786 \accepts "ImproVoice"
790 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
791 c4 c^"undress" c_"while playing :)" c }
797 These settings are defined within a @code{\context} block inside a
798 @code{\layout} block,
808 In the following discussion, the example input shown should go in place
809 of the @dots{} in the previous fragment.
811 First it is necessary to define a name for the new context:
817 Since it is similar to the @code{Voice}, we want commands that work
818 on (existing) @code{Voice}s to remain working. This is achieved by
819 giving the new context an alias @code{Voice},
825 The context will print notes and instructive texts, so we need to add
826 the engravers which provide this functionality,
829 \consists Note_heads_engraver
830 \consists Text_engraver
833 but we only need this on the center line,
836 \consists Pitch_squash_engraver
837 squashedPosition = #0
840 The @rinternals{Pitch_squash_engraver} modifies note heads (created
841 by @rinternals{Note_heads_engraver}) and sets their vertical
842 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
845 The notes look like a slash, and have no stem,
848 \override NoteHead #'style = #'slash
849 \override Stem #'transparent = ##t
852 All these plug-ins have to cooperate, and this is achieved with a
853 special plug-in, which must be marked with the keyword @code{\type}.
854 This should always be @code{Engraver_group}.
857 \type "Engraver_group"
865 \type "Engraver_group"
866 \consists "Note_heads_engraver"
867 \consists "Text_engraver"
868 \consists Pitch_squash_engraver
869 squashedPosition = #0
870 \override NoteHead #'style = #'slash
871 \override Stem #'transparent = ##t
877 Contexts form hierarchies. We want to hang the @code{ImproVoice}
878 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
879 modify the @code{Staff} definition with the @code{\accepts}
890 The opposite of @code{\accepts} is @code{\denies},
891 which is sometimes needed when reusing existing context definitions.
893 Putting both into a @code{\layout} block, like
903 \accepts "ImproVoice"
908 Then the output at the start of this subsection can be entered as
916 c c_"while playing :)"
923 @node Aligning contexts
924 @subsection Aligning contexts
926 New contexts may be aligned above or below existing contexts. This
927 could be useful in setting up a vocal staff (@rlearning{Vocal ensembles}) and
930 @c TODO Better example needed. Ref LM, and expand on it.
933 @funindex alignAboveContext
934 @funindex alignBelowContext
936 @lilypond[quote,ragged-right]
939 \relative c' \new Staff = "main" {
942 \new Staff \with { alignAboveContext = #"main" } \ossia
949 @cindex nested contexts
950 @cindex contexts, nested
955 Contexts like @code{PianoStaff} can contain other contexts
956 nested within them. Contexts which are acceptable for nesting
957 are defined by the @qq{accepts} list of a context. Contexts
958 which are not in this list are placed below the outer context
959 in the printed score.
960 For example, the @code{PianoStaff} context is defined by default
961 to accept @code{Staff} and @code{FiguredBass} contexts within
962 it, but not (for example) a @code{Lyrics} context. So in the
963 following structure the lyrics are placed below the piano staff
964 rather than between the two staves:
966 @lilypond[verbatim,quote,relative=1]
969 \new Staff { e4 d c2 }
970 \addlyrics { Three blind mice }
978 The @qq{accepts} list of a context can be modified to include
979 additional nested contexts, so if we wanted the lyrics to appear
980 between the two staves we could use:
982 @lilypond[verbatim,quote,relative=1]
983 \new PianoStaff \with { \accepts Lyrics }
985 \new Staff { e4 d c2 }
986 \addlyrics { Three blind mice }
994 The opposite of @code{\accepts} is @code{\denies}; this removes a
995 context from the @qq{accepts} list.
997 @node Explaining the Internals Reference
998 @section Explaining the Internals Reference
1002 * Navigating the program reference::
1003 * Layout interfaces::
1004 * Determining the grob property::
1005 * Naming conventions::
1008 @node Navigating the program reference
1009 @subsection Navigating the program reference
1011 @c TODO remove this (it's in the LM)
1012 @c Replace with more factual directions
1014 Suppose we want to move the fingering indication in the fragment
1017 @lilypond[quote,fragment,relative=2,verbatim]
1023 If you visit the documentation on fingering instructions (in
1024 @ref{Fingering instructions}), you will notice:
1029 Internals Reference: @rinternals{Fingering}.
1034 @c outdated info; probably will delete.
1036 This fragment points to two parts of the program reference: a page
1037 on @code{FingeringEvent} and one on @code{Fingering}.
1039 The page on @code{FingeringEvent} describes the properties of the music
1040 expression for the input @code{-2}. The page contains many links
1041 forward. For example, it says
1044 Accepted by: @rinternals{Fingering_engraver},
1048 That link brings us to the documentation for the Engraver, the
1052 This engraver creates the following layout objects: @rinternals{Fingering}.
1055 In other words, once the @code{FingeringEvent}s are interpreted, the
1056 @code{Fingering_engraver} plug-in will process them.
1060 @c I can't figure out what this is supposed to mean. -gp
1062 The @code{Fingering_engraver} is also listed to create
1063 @rinternals{Fingering} objects,
1065 @c old info? it doesn't make any sense to me with our current docs.
1067 second bit of information listed under @b{See also} in the Notation
1072 The programmer's reference is available as an HTML document. It is
1073 highly recommended that you read it in HTML form, either online or
1074 by downloading the HTML documentation. This section will be much more
1075 difficult to understand if you are using the
1079 Follow the link to @rinternals{Fingering}. At the top of the
1083 Fingering objects are created by: @rinternals{Fingering_engraver} and
1084 @rinternals{New_fingering_engraver}.
1087 By following related links inside the program reference, we can follow the
1088 flow of information within the program:
1092 @item @rinternals{Fingering}:
1093 @rinternals{Fingering} objects are created by:
1094 @rinternals{Fingering_engraver}
1096 @item @rinternals{Fingering_engraver}:
1097 Music types accepted: @rinternals{fingering-event}
1099 @item @rinternals{fingering-event}:
1100 Music event type @code{fingering-event} is in Music expressions named
1101 @rinternals{FingeringEvent}
1104 This path goes against the flow of information in the program: it
1105 starts from the output, and ends at the input event. You could
1106 also start at an input event, and read with the flow of
1107 information, eventually ending up at the output object(s).
1109 The program reference can also be browsed like a normal document. It
1110 contains chapters on
1112 @rinternals{Music definitions},
1115 @code{Music definitions}
1117 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1118 chapter lists all the definitions used and all properties that may be
1122 @node Layout interfaces
1123 @subsection Layout interfaces
1125 @cindex interface, layout
1126 @cindex layout interface
1129 The HTML page that we found in the previous section describes the
1130 layout object called @rinternals{Fingering}. Such an object is a
1131 symbol within the score. It has properties that store numbers (like
1132 thicknesses and directions), but also pointers to related objects. A
1133 layout object is also called a @emph{Grob}, which is short for Graphical
1134 Object. For more details about Grobs, see @rinternals{grob-interface}.
1136 The page for @code{Fingering} lists the definitions for the
1137 @code{Fingering} object. For example, the page says
1140 @code{padding} (dimension, in staff space):
1146 which means that the number will be kept at a distance of at least 0.5
1150 Each layout object may have several functions as a notational or
1151 typographical element. For example, the Fingering object
1152 has the following aspects
1156 Its size is independent of the horizontal spacing, unlike slurs or beams.
1159 It is a piece of text. Granted, it is usually a very short text.
1162 That piece of text is typeset with a font, unlike slurs or beams.
1165 Horizontally, the center of the symbol should be aligned to the
1166 center of the note head.
1169 Vertically, the symbol is placed next to the note and the staff.
1172 The vertical position is also coordinated with other superscript
1173 and subscript symbols.
1176 Each of these aspects is captured in so-called @emph{interface}s,
1177 which are listed on the @rinternals{Fingering} page at the bottom
1180 This object supports the following interfaces:
1181 @rinternals{item-interface},
1182 @rinternals{self-alignment-interface},
1183 @rinternals{side-position-interface}, @rinternals{text-interface},
1184 @rinternals{text-script-interface}, @rinternals{font-interface},
1185 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1188 Clicking any of the links will take you to the page of the respective
1189 object interface. Each interface has a number of properties. Some of
1190 them are not user-serviceable (@q{Internal properties}), but others
1193 We have been talking of @emph{the} @code{Fingering} object, but actually it
1194 does not amount to much. The initialization file (see
1195 @rlearning{Other sources of information})
1196 @file{scm/@/define@/-grobs@/.scm} shows the soul of the @q{object},
1201 (avoid-slur . around)
1202 (slur-padding . 0.2)
1203 (staff-padding . 0.5)
1204 (self-alignment-X . 0)
1205 (self-alignment-Y . 0)
1206 (script-priority . 100)
1207 (stencil . ,ly:text-interface::print)
1208 (direction . ,ly:script-interface::calc-direction)
1209 (font-encoding . fetaNumber)
1210 (font-size . -5) ; don't overlap when next to heads.
1211 (meta . ((class . Item)
1212 (interfaces . (finger-interface
1214 text-script-interface
1216 side-position-interface
1217 self-alignment-interface
1218 item-interface))))))
1222 As you can see, the @code{Fingering} object is nothing more than a
1223 bunch of variable settings, and the webpage in the Internals Reference
1224 is directly generated from this definition.
1227 @node Determining the grob property
1228 @subsection Determining the grob property
1230 @c TODO remove this (it's in the LM)
1231 @c Replace with more factual directions
1233 Recall that we wanted to change the position of the @b{2} in
1235 @lilypond[quote,fragment,relative=2,verbatim]
1241 Since the @b{2} is vertically positioned next to its note, we have to
1242 meddle with the interface associated with this positioning. This is
1243 done using @code{side-position-interface}. The page for this interface
1247 @code{side-position-interface}
1249 Position a victim object (this one) next to other objects (the
1250 support). The property @code{direction} signifies where to put the
1251 victim object relative to the support (left or right, up or down?)
1256 Below this description, the variable @code{padding} is described as
1261 (dimension, in staff space)
1263 Add this much extra space between objects that are next to each other.
1267 By increasing the value of @code{padding}, we can move the
1268 fingering away from the note head. The following command inserts
1269 3 staff spaces of white
1270 between the note and the fingering:
1272 \once \override Voice.Fingering #'padding = #3
1275 Inserting this command before the Fingering object is created,
1276 i.e., before @code{c2}, yields the following result:
1278 @lilypond[quote,relative=2,fragment,verbatim]
1279 \once \override Voice.Fingering #'padding = #3
1286 In this case, the context for this tweak is @code{Voice}. This
1287 fact can also be deduced from the program reference, for the page for
1288 the @rinternals{Fingering_engraver} plug-in says
1291 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1295 @node Naming conventions
1296 @subsection Naming conventions
1298 Another thing that is needed, is an overview of the various naming
1302 @item scheme functions: lowercase-with-hyphens (incl. one-word
1304 @item scheme functions: ly:plus-scheme-style
1305 @item music events, music classes and music properties:
1307 @item Grob interfaces: scheme-style
1308 @item backend properties: scheme-style (but X and Y!)
1309 @item contexts (and MusicExpressions and grobs): Capitalized or
1311 @item context properties: lowercaseFollowedByCamelCase
1313 Capitalized_followed_by_lowercase_and_with_underscores
1316 Questions to be answered:
1318 @item Which of these are conventions and which are rules?
1319 @item Which are rules of the underlying language, and which are
1323 @node Modifying properties
1324 @section Modifying properties
1326 @c TODO change the menu and subsection node names to use
1327 @c backslash once the new macro to handle the refs
1328 @c is available. Need to find and change all refs at
1329 @c the same time. -td
1332 * Overview of modifying properties::
1334 * The override command::
1335 * The tweak command::
1336 * set versus override::
1340 @node Overview of modifying properties
1341 @subsection Overview of modifying properties
1343 Each context is responsible for creating certain types of graphical
1344 objects. The settings used for printing these objects are also stored by
1345 context. By changing these settings, the appearance of objects can be
1348 There are two different kinds of properties stored in contexts:
1349 context properties and grob properties. Context properties are
1350 properties that apply to the context as a whole and control
1351 how the context itself is displayed. In contrast, grob properties
1352 apply to specific grob types that will be displayed in the context.
1354 The @code{\set} and @code{\unset} commands are used to change values
1355 for context properties. The @code{\override} and @code{\revert}
1356 commands are used to change values for grob properties.
1359 The syntax for this is
1362 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1365 Here @var{name} is the name of a graphical object, like
1366 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1367 variable of the formatting system (@q{grob property} or @q{layout
1368 property}). The latter is a symbol, so it must be quoted. The
1369 subsection @ref{Modifying properties}, explains what to fill in
1370 for @var{name}, @var{property}, and @var{value}. Here we only
1371 discuss the functionality of this command.
1376 \override Staff.Stem #'thickness = #4.0
1380 makes stems thicker (the default is 1.3, with staff line thickness as a
1381 unit). Since the command specifies @code{Staff} as context, it only
1382 applies to the current staff. Other staves will keep their normal
1383 appearance. Here we see the command in action:
1385 @lilypond[quote,verbatim,relative=2,fragment]
1387 \override Staff.Stem #'thickness = #4.0
1393 The @code{\override} command changes the definition of the @code{Stem}
1394 within the current @code{Staff}. After the command is interpreted
1395 all stems are thickened.
1397 Analogous to @code{\set}, the @var{context} argument may be left out,
1398 causing the default context @code{Voice} to be used. Adding
1399 @code{\once} applies the change during one timestep only.
1401 @lilypond[quote,fragment,verbatim,relative=2]
1403 \once \override Stem #'thickness = #4.0
1408 The @code{\override} must be done before the object is
1409 started. Therefore, when altering @emph{Spanner} objects such as slurs
1410 or beams, the @code{\override} command must be executed at the moment
1411 when the object is created. In this example,
1413 @lilypond[quote,fragment,verbatim,relative=2]
1414 \override Slur #'thickness = #3.0
1416 \override Beam #'thickness = #0.6
1421 the slur is fatter but the beam is not. This is because the command for
1422 @code{Beam} comes after the Beam is started, so it has no effect.
1424 Analogous to @code{\unset}, the @code{\revert} command for a context
1425 undoes an @code{\override} command; like with @code{\unset}, it only
1426 affects settings that were made in the same context. In other words, the
1427 @code{\revert} in the next example does not do anything.
1430 \override Voice.Stem #'thickness = #4.0
1431 \revert Staff.Stem #'thickness
1434 Some tweakable options are called @q{subproperties} and reside inside
1435 properties. To tweak those, use commands of the form
1437 @c leave this as a long long
1439 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1446 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1453 @rinternals{Backend},
1454 @rinternals{All layout objects},
1455 @rinternals{OverrideProperty},
1456 @rinternals{RevertProperty},
1457 @rinternals{PropertySet}.
1462 The back-end is not very strict in type-checking object properties.
1463 Cyclic references in Scheme values for properties can cause hangs
1464 or crashes, or both.
1468 @node The set command
1469 @subsection The @code{\set} command
1473 @cindex changing properties
1475 Each context has a set of @emph{properties}, variables contained
1476 in that context. Context properties are changed with the @code{\set}
1477 command, which has the following syntax:
1480 \set @var{context}.@var{property} = #@var{value}
1483 @var{value} is a Scheme object, which is why it must be preceded by
1484 the @code{#} character.
1486 Contexts properties are usually named in
1487 @code{studlyCaps}. They mostly control the translation from
1488 music to notation, e.g. @code{localKeySignature} (for determining
1489 whether to print accidentals), or @code{measurePosition} (for
1490 determining when to print a bar line). Context properties can
1491 change value over time while interpreting a piece of music;
1492 @code{measurePosition} is an obvious example of
1493 this. Context properties are modified with @code{\set}.
1495 For example, multimeasure rests will be combined into a single bar
1496 if the context property @code{skipBars} is set to @code{#t}:
1498 @lilypond[quote,verbatim,relative=2,fragment]
1500 \set Score.skipBars = ##t
1504 If the @var{context} argument is left out, then the property will be
1505 set in the current bottom context (typically @code{ChordNames},
1506 @code{Voice}, @code{TabVoice}, or @code{Lyrics}).
1508 @lilypond[quote,verbatim,relative=2,fragment]
1509 \set Score.autoBeaming = ##f
1513 \set autoBeaming = ##t
1521 The change is applied @q{on-the-fly}, during the music, so that the
1522 setting only affects the second group of eighth notes.
1524 Note that the bottom-most context does not always contain the property
1525 that you wish to change -- for example, attempting to set the
1526 @code{skipBars} property of the default bottom context, in this case
1527 @code{Voice}, will have no effect, because skipBars is a property of
1528 the @code{Score} context.
1530 @lilypond[quote,verbatim,relative=2,fragment]
1536 Contexts are hierarchical, so if an enclosing context was specified, for
1537 example @code{Staff}, then the change would also apply to all
1538 @code{Voice}s in the current staff.
1542 The @code{\unset} command:
1545 \unset @var{context}.@var{property}
1549 is used to remove the definition of @var{property} from
1550 @var{context}. This command removes
1551 the definition only if it is set in @var{context}.
1552 Properties that have been set in enclosing contexts will
1553 not be altered by an unset in an enclosed context:
1555 @lilypond[quote,verbatim,relative=2,fragment]
1556 \set Score.autoBeaming = ##t
1561 \unset Score.autoBeaming
1569 Like @code{\set}, the @var{context} argument does not have to be
1570 specified for a bottom context, so the two statements
1573 \set Voice.autoBeaming = ##t
1574 \set autoBeaming = ##t
1578 are equivalent if the current bottom context is @code{Voice}.
1582 Preceding a @code{\set} command by @code{\once} makes the
1583 setting apply to only a single time-step:
1585 @lilypond[quote,verbatim,relative=2,fragment]
1587 \once \set fontSize = #4.7
1592 A full description of all available context properties is in the
1593 internals reference, see
1595 @rinternals{Tunable context properties}.
1598 Translation @expansion{} Tunable context properties.
1603 Internals Reference:
1605 @rinternals{Tunable context properties}.
1608 @cindex grob properties
1609 @cindex properties, grob
1613 @node The override command
1614 @subsection The @code{\override} command
1616 There is a special type of context property: the grob
1617 description. Grob descriptions are named in @code{StudlyCaps}
1618 (starting with capital letters). They contain the
1619 @q{default settings} for a particular kind of grob as an
1620 association list. See @file{scm/@/define@/-grobs@/.scm}
1621 to see the settings for each grob description. Grob descriptions
1622 are modified with @code{\override}.
1624 @code{\override} is actually a shorthand;
1627 \override @var{context}.@var{GrobName} #'@var{property} = #@var{value}
1631 is more or less equivalent to
1633 @c leave this long line -gp
1635 \set @var{context}.@var{GrobName} =
1636 #(cons (cons '@var{property} @var{value})
1637 <previous value of @var{context}.@var{GrobName}>)
1640 The value of @code{context}.@code{GrobName} (the alist) is used to initialize
1641 the properties of individual grobs. Grobs have
1642 properties, named in Scheme style, with
1643 @code{dashed-words}. The values of grob properties change
1644 during the formatting process: formatting basically amounts
1645 to computing properties using callback functions.
1647 For example, we can increase the thickness of a note stem by
1648 overriding the @code{thickness} property of the @code{Stem}
1651 @lilypond[quote, verbatim, relative=2, fragment]
1653 \override Voice.Stem #'thickness = #3.0
1657 If no context is specified in an @code{\override}, the bottom
1660 @lilypond[quote, verbatim, relative=2, fragment]
1661 { \override Staff.Stem #'thickness = #3.0
1665 \override Stem #'thickness = #0.5
1675 @cindex reverting overrides
1676 @cindex overrides, reverting
1678 The effects of @code{\override} can be undone by @code{\revert}:
1680 @lilypond[quote, verbatim, relative=2, fragment]
1682 \override Voice.Stem #'thickness = #3.0
1684 \revert Voice.Stem #'thickness
1688 The effects of @code{\override} and @code{\revert} apply to all
1689 grobs in the affected context from the current time forward:
1691 @lilypond[quote, verbatim, relative=2, fragment]
1696 \override Staff.Stem #'thickness = #3.0
1700 \revert Staff.Stem #'thickness
1708 @cindex overriding for only one moment
1710 @code{\once} can be used with @code{\override}
1711 to affect only the current time step:
1713 @lilypond[quote, verbatim, relative=2, fragment]
1717 \override Stem #'thickness = #3.0
1721 \once \override Stem #'thickness = #3.0
1730 Commands which change output generally look like
1733 \override Voice.Stem #'thickness = #3.0
1737 To construct this tweak we must determine these bits of information:
1740 @item the context: here @code{Voice}.
1741 @item the layout object: here @code{Stem}.
1742 @item the layout property: here @code{thickness}.
1743 @item a sensible value: here @code{3.0}.
1746 Some tweakable options are called @q{subproperties} and reside inside
1747 properties. To tweak those, use commands in the form
1750 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1753 @cindex internal documentation
1754 @cindex finding graphical objects
1755 @cindex graphical object descriptions
1758 @cindex internal documentation
1760 For many properties, regardless of the data type of the property, setting the
1761 property to false ( @code{##f} ) will result in turning it off, causing
1762 LilyPond to ignore that property entirely. This is particularly useful for
1763 turning off grob properties which may otherwise be causing problems.
1765 We demonstrate how to glean this information from the notation manual
1766 and the program reference.
1771 Internals Reference:
1772 @rinternals{Backend}
1774 @node The tweak command
1775 @subsection The @code{\tweak} command
1780 Changing grob properties
1781 with @code{\override} causes the changes to apply to all of the
1782 given grobs in the context at the moment the change applies.
1783 Sometimes, however, it is desirable to have changes apply to just
1784 one grob, rather than to all grobs in the affected context. This is
1785 accomplished with the @code{\tweak} command, which has the following
1789 \tweak #'@code{grob-property} #@code{value}
1792 The @code{\tweak} command applies to the object that immediately
1793 follows @code{value} in the music stream.
1796 In some cases, it is possible to take a short-cut for tuning
1797 graphical objects. For objects that are created directly from
1798 an item in the input file, you can use the @code{\tweak} command.
1801 @lilypond[relative=2,verbatim,quote]
1806 \tweak #'duration-log #1
1809 -\tweak #'padding #8
1815 But the main use of the @code{\tweak} command is to modify just
1816 one of a number of notation elements which start at the same musical
1817 moment, like the notes of a chord, or tuplet brackets which start
1820 The @code{\tweak} command sets a property in the following object
1821 directly, without requiring the grob name or context to be
1822 specified. For this to work, it is necessary for the @code{\tweak}
1823 command to remain immediately adjacent to the object to which it is
1824 to apply after the input file has been converted to a music stream.
1825 This is often not the case, as many additional elements are inserted
1826 into the music stream implicitly. For example, when a note which is
1827 not part of a chord is processed, LilyPond implicitly inserts a
1828 @code{ChordEvent} event before the note, so separating the tweak
1829 from the note. However, if chord symbols are placed round the
1830 tweak and the note, the @code{\tweak} command comes after the
1831 @code{ChordEvent} in the music stream, so remaining adjacent to the
1832 note, and able to modify it.
1836 @lilypond[relative=2,verbatim,quote]
1837 <\tweak #'color #red c>4
1843 @lilypond[relative=2,verbatim,quote]
1844 \tweak #'color #red c4
1849 For an introduction to the syntax and uses of the tweak command
1850 see @rlearning{Tweaking methods}.
1852 When several similar items are placed at the same musical moment,
1853 the @code{\override} command cannot be used to modify just one of
1854 them -- this is where the @code{\tweak} command must be used.
1855 Items which may appear more than once at the same musical moment
1856 include the following:
1858 @c TODO expand to include any further uses of \tweak
1860 @item note heads of notes inside a chord
1861 @item articulation signs on a single note
1862 @item ties between notes in a chord
1863 @item tuplet brackets starting at the same time
1866 @c TODO add examples of these
1868 @cindex chord, modifying one note in
1870 In this example, the color of one note head and the type of another
1871 note head are modified within a single chord:
1873 @lilypond[relative=2,verbatim,quote]
1878 \tweak #'duration-log #1
1883 @code{\tweak} can be used to modify slurs:
1885 @lilypond[verbatim,quote,relative=1]
1886 c-\tweak #'thickness #5 ( d e f)
1890 For the @code{\tweak} command to work, it must
1891 remain immediately adjacent to the object to which it is
1892 to apply after the input file has been converted to a music stream.
1893 At times, LilyPond may insert additional items into the music stream
1894 during the parsing process. For example, when a note that is not
1895 explicitly part of a chord will be placed in a chord by LilyPond,
1896 so notes to be modified with @code{\tweak} must be placed inside
1899 @lilypond[relative=2,verbatim,quote]
1900 \tweak #'color #red c4
1901 <\tweak #'color #red c>4
1904 The @code{\tweak} command cannot be used to modify any item
1905 that does not appear explicitly in the input file. In particular
1906 it cannot be used to modify stems,
1907 beams or accidentals directly, since these are generated later by
1908 note heads, rather than by music elements in the input stream.
1909 Nor can @code{\tweak} be used to modify clefs or time
1910 signatures, since these become separated from any preceding
1911 @code{\tweak} command in the input stream by the automatic
1912 insertion of extra elements required to specify the context.
1914 Several @code{\tweak} commands may be placed before a
1915 notational element -- all affect it:
1917 @lilypond[verbatim,quote,relative=1]
1919 -\tweak #'style #'dashed-line
1920 -\tweak #'dash-fraction #0.2
1921 -\tweak #'thickness #3
1922 -\tweak #'color #red
1927 The music stream which is generated from a section of an input file,
1928 including any automatically inserted elements, may be examined,
1929 see @rextend{Displaying music expressions}. This may be helpful in
1930 determining what may be modified by a @code{\tweak} command, or
1931 in determining how to adjust the input to make a @code{\tweak}
1937 @rlearning{Tweaking methods}.
1940 @rextend{Displaying music expressions}.
1945 @cindex tweaks in a variable
1946 The @code{\tweak} command cannot be used inside a variable.
1948 @cindex tweaks in lyrics
1949 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1951 @cindex tweaking control points
1952 @cindex control points, tweaking
1954 The @code{\tweak} command will apply to only the first of several
1955 generated ties in a chord.
1957 @node set versus override
1958 @subsection @code{\set} vs. @code{\override}
1960 TODO -- This section is probably unnecessary now.
1963 We have seen two methods of changing properties: @code{\set} and
1964 @code{\override}. There are actually two different kinds of
1967 @code{fontSize} is a special property: it is equivalent to
1968 entering @code{\override ... #'font-size} for all pertinent
1969 objects. Since this is a common change, the special
1970 property (modified with @code{\set}) was created.
1974 @node Useful concepts and properties
1975 @section Useful concepts and properties
1980 * Direction and placement::
1981 * Context layout order::
1982 * Distances and measurements::
1983 * Staff symbol properties::
1985 * Visibility of objects::
1987 * Rotating objects::
1991 @subsection Input modes
1993 The way in which the notation contained within an input file is
1994 interpreted is determined by the current input mode.
1998 This is activated with the @code{\chordmode} command, and causes
1999 input to be interpreted with the syntax of chord notation, see
2000 @ref{Chord notation}. Chords are rendered as notes on a staff.
2002 Chord mode is also activated with the @code{\chords} command.
2003 This also creates a new @code{ChordNames} context and
2004 causes the following input to be interpreted with the syntax of
2005 chord notation and rendered as chord names in the @code{ChordNames}
2006 context, see @ref{Printing chord names}.
2010 This is activated with the @code{\drummode} command, and causes
2011 input to be interpreted with the syntax of drum notation, see
2012 @ref{Basic percussion notation}.
2014 Drum mode is also activated with the @code{\drums} command.
2015 This also creates a new @code{DrumStaff} context and causes the
2016 following input to be interpreted with the syntax of drum notation
2017 and rendered as drum symbols on a drum staff, see @ref{Basic
2018 percussion notation}.
2020 @strong{Figure mode}
2022 This is activated with the @code{\figuremode} command, and causes
2023 input to be interpreted with the syntax of figured bass, see
2024 @ref{Entering figured bass}.
2026 Figure mode is also activated with the @code{\figures} command.
2027 This also creates a new @code{FiguredBass} context and causes the
2028 following input to be interpreted with the figured bass syntax
2029 and rendered as figured bass symbols in the @code{FiguredBass}
2030 context, see @ref{Introduction to figured bass}.
2032 @strong{Fret and tab modes}
2034 There are no special input modes for entering fret and tab symbols.
2036 To create tab diagrams, enter notes or chords in note mode and
2037 render them in a @code{TabStaff} context, see
2038 @ref{Default tablatures}.
2040 To create fret diagrams above a staff, you have two choices.
2041 You can either use the @code{FretBoards} context (see
2042 @ref{Automatic fret diagrams} or you can enter them as a markup
2043 above the notes using the @code{\fret-diagram} command (see
2044 @ref{Fret diagram markups}).
2046 @strong{Lyrics mode}
2048 This is activated with the @code{\lyricmode} command, and causes
2049 input to be interpreted as lyric syllables with optional durations
2050 and associated lyric modifiers, see @ref{Vocal music}.
2052 Lyric mode is also activated with the @code{\addlyrics} command.
2053 This also creates a new @code{Lyrics} context and an implicit
2054 @code{\lyricsto} command which associates the following lyrics
2055 with the preceding music.
2057 @strong{Markup mode}
2059 This is activated with the @code{\markup} command, and causes
2060 input to be interpreted with the syntax of markup, see
2061 @ref{Text markup commands}.
2063 @c silly work-around for texinfo broken-ness
2064 @c (@strong{Note...} causes a spurious cross-reference in Info)
2067 This is the default mode or it may be activated with the
2068 @code{\notemode} command. Input is interpreted as pitches,
2069 durations, markup, etc and typeset as musical notation on a staff.
2071 It is not normally necessary to specify note mode explicitly, but
2072 it may be useful to do so in certain situations, for example if you
2073 are in lyric mode, chord mode or any other mode and want to insert
2074 something that only can be done with note mode syntax.
2076 For example, to indicate dynamic markings for the verses of a
2077 choral pieces it is necessary to enter note mode to interpret
2080 @lilypond[verbatim,relative=2,quote]
2083 \notemode{\set stanza = \markup{ \dynamic f 1. } }
2087 \notemode{\set stanza = \markup{ \dynamic p 2. } }
2094 @node Direction and placement
2095 @subsection Direction and placement
2097 In typesetting music the direction and placement of many items is
2098 a matter of choice. For example, the stems of notes can
2099 be directed up or down; lyrics, dynamics, and other expressive
2100 marks may be placed above or below the staff; text may be aligned
2101 left, right or center; etc. Most of these choices may be left to
2102 be determined automatically by LilyPond, but in some cases it may
2103 be desirable to force a particular direction or placement.
2105 @strong{Articulation direction indicators}
2107 By default some directions are always up or always down (e.g.
2108 dynamics or fermata), while other things can alternate between
2109 up or down based on the stem direction (like slurs or accents).
2111 @c TODO Add table showing these
2113 The default action may be overridden by prefixing the articulation
2114 by a @emph{direction indicator}. Three direction indicators are
2115 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
2116 and @code{-} (meaning @qq{use default direction}). The direction
2117 indicator can usually be omitted, in which case @code{-} is assumed,
2118 but a direction indicator is @strong{always} required before
2121 @item @code{\tweak} commands
2122 @item @code{\markup} commands
2123 @item @code{\tag} commands
2124 @item string markups, e.g. -"string"
2125 @item fingering instructions, e.g. @code{-1}
2126 @item articulation shortcuts, e.g. @code{-.}, @code{->}, @code{--}
2129 Direction indicators affect only the next note:
2131 @lilypond[verbatim,quote,relative=2]
2138 @strong{The direction property}
2140 The position or direction of many layout objects is controlled
2141 by the @code{direction} property.
2143 The value of the @code{direction} property may be
2144 set to @code{1}, meaning @qq{up} or @qq{above}, or to @code{-1},
2145 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
2146 @code{DOWN} may be used instead of @code{1} and @code{-1}
2147 respectively. The default direction may be specified by setting
2148 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
2149 in many cases predefined commands
2150 exist to specify the direction. These are all of the form
2153 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
2156 where @code{xxxNeutral} means @qq{use the default direction}.
2157 See @rlearning{Within-staff objects}.
2159 In a few cases, arpeggio being the only common example, the value
2160 of the @code{direction} property specifies whether the object
2161 is to be placed to the right or left of the parent object. In
2162 this case @code{-1} or @code{LEFT} means @qq{to the left} and
2163 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
2164 or @code{CENTER} means @qq{use the default} direction, as before.
2167 These all have side-axis set to #X
2168 AmbitusAccidental - direction has no effect
2170 StanzaNumber - not tried
2171 TrillPitchAccidental - not tried
2172 TrillPitchGroup - not tried
2175 These indications affect all notes until they are cancelled.
2177 @lilypond[verbatim,quote,relative=2]
2187 @node Context layout order
2188 @subsection Context layout order
2190 @cindex contexts, layout order
2192 Contexts are normally positioned in a system from top to bottom
2193 in the order in which they are encountered in the input file. When
2194 contexts are nested, the outer context will include inner nested
2195 contexts as specified in the input file, provided the inner contexts
2196 are included in the outer context's @qq{accepts} list. Nested
2197 contexts which are not included in the outer context's @qq{accepts}
2198 list will be repositioned below the outer context rather than nested
2201 Note that a context will be silently created implicitly if a command
2202 is encountered when there is no suitable context available to
2203 contain it. This can give rise to unexpected new staves or scores.
2205 The default order in which contexts are laid out and the
2206 @qq{accepts} list can be changed, see @ref{Aligning contexts}.
2210 @rprogram{An extra staff appears}.
2213 @node Distances and measurements
2214 @subsection Distances and measurements
2216 @cindex distances, absolute
2217 @cindex distances, scaled
2224 Distances in LilyPond are of two types: absolute and scaled.
2226 Absolute distances are used for specifying margins, indents, and
2227 other page layout details, and are by default specified in
2228 millimeters. Distances may be specified in other units by
2229 following the quantity by @code{\mm}, @code{\cm},
2230 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27
2231 of an inch). Page layout distances can also be specified in
2232 scalable units (see the following paragraph) by appending
2233 @code{\staff-space} to the quantity.
2234 Page layout is described in detail in @ref{Page formatting}.
2236 Scaled distances are always specified in units of the staff-space
2237 or, rarely, the half staff-space. The staff-space is the distance
2238 between two adjacent staff lines. The default value can be changed
2239 globally by setting the global staff size, or it can be overridden
2240 locally by changing the @code{staff-space} property of
2241 @code{StaffSymbol}. Scaled distances automatically scale with any
2242 change to the either the global staff size or the
2243 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2244 automatically only with changes to the global staff size.
2245 The global staff size thus enables the overall size of a rendered
2246 score to be easily varied. For the methods of setting the global
2247 staff size see @ref{Setting the staff size}.
2251 If just a section of a score needs to be rendered to a different
2252 scale, for example an ossia section or a footnote, the global staff
2253 size cannot simply be changed as this would affect the entire score.
2254 In such cases the change in size is made by overriding both the
2255 @code{staff-space} property of @code{StaffSymbol} and the size of
2256 the fonts. A Scheme function, @code{magstep}, is available to
2257 convert from a font size change to the equivalent change in
2258 @code{staff-space}. For an explanation and an example of its use,
2259 see @rlearning{Length and thickness of objects}.
2264 @rlearning{Length and thickness of objects}.
2267 @ref{Page formatting},
2268 @ref{Setting the staff size}.
2271 @node Staff symbol properties
2272 @subsection Staff symbol properties
2274 @cindex adjusting staff symbol
2275 @cindex drawing staff symbol
2276 @cindex staff symbol, setting of
2278 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2279 @c Need to think of uses for these properties. Eg 'line-positions
2280 @c is used in a snippet to thicken centre line.
2281 @c If retained, add @ref to here in 1.6.2 -td
2283 The vertical position of staff lines and the number of staff lines
2284 can be defined at the same time. As the following example shows,
2285 note positions are not influenced by the staff line positions.
2287 @warning{The @code{'line-positions} property overrides the
2288 @code{'line-count} property. The number of staff lines is
2289 implicitly defined by the number of elements in the list of values
2290 for @code{'line-positions}.}
2292 @lilypond[verbatim,quote,relative=1]
2294 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
2299 The width of a staff can be modified. The units are staff
2300 spaces. The spacing of objects inside the staff is not affected by
2303 @lilypond[verbatim,quote,relative=1]
2305 \override StaffSymbol #'width = #23
2312 @subsection Spanners
2314 Many objects of musical notation extend over several notes or even
2315 several bars. Examples are slurs, beams, tuplet brackets, volta
2316 repeat brackets, crescendi, trills, and glissandi. Such objects
2317 are collectively called @qq{spanners}, and have special properties to control
2318 their appearance and behaviour. Some of these properties are common
2319 to all spanners; others are restricted to a sub-set of the spanners.
2321 All spanners support the @code{spanner-interface}. A few, esentially
2322 those that draw a straight line between the two objects, support in
2323 addition the @code{line-spanner-interface}.
2325 @unnumberedsubsubsec Using the @code{spanner-interface}
2327 This interface provides two properties that apply to several spanners.
2329 @strong{@i{The @code{minimum-length} property}}
2331 The minimum length of the spanner is specified by the
2332 @code{minimum-length} property. Increasing this usually has the
2333 necessary effect of increasing the spacing of the notes between the
2334 two end points. However, this override has no effect on
2335 many spanners, as their length is determined by other considerations.
2336 A few examples where it is effective are shown below.
2346 Works as long as callback is made:
2350 Works not at all for:
2359 @lilypond[verbatim,quote,relative=2]
2362 % increase the length of the tie
2363 -\tweak #'minimum-length #5
2367 @lilypond[verbatim,quote,relative=2]
2369 \compressFullBarRests
2371 % increase the length of the rest bar
2372 \once \override MultiMeasureRest #'minimum-length = #20
2377 @lilypond[verbatim,quote,relative=2]
2379 % increase the length of the hairpin
2380 \override Hairpin #'minimum-length = #20
2384 This override can also be used to increase the length of slurs and
2387 @lilypond[verbatim,quote,relative=2]
2390 -\tweak #'minimum-length #5
2395 -\tweak #'minimum-length #5
2399 For some layout objects, the @code{minimum-length} property becomes
2400 effective only if the @code{set-spacing-rods} procedure is called
2401 explicitly. To do this, the @code{springs-and-rods} property should
2402 be set to @code{ly:spanner::set-spacing-rods}. For example,
2403 the minimum length of a glissando has no effect unless the
2404 @code{springs-and-rods} property is set:
2406 @lilypond[verbatim,quote,relative=1]
2410 % not effective alone
2411 \once \override Glissando #'minimum-length = #20
2414 % effective only when both overrides are present
2415 \once \override Glissando #'minimum-length = #20
2416 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2420 The same is true of the @code{Beam} object:
2422 @lilypond[verbatim,quote,relative=1]
2423 % not effective alone
2424 \once \override Beam #'minimum-length = #20
2427 % effective only when both overrides are present
2428 \once \override Beam #'minimum-length = #20
2429 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2433 @strong{@i{The @code{to-barline} property}}
2435 The second useful property of the @code{spanner-interface} is
2436 @code{to-barline}. By default this is true, causing hairpins and
2437 other spanners which are terminated on the first note of a measure to
2438 end instead on the immediately preceding bar line. If set to false,
2439 the spanner will extend beyond the bar line and end on the note
2442 @lilypond[verbatim,quote,relative=2]
2443 a \< a a a a \! a a a \break
2444 \override Hairpin #'to-barline = ##f
2445 a \< a a a a \! a a a
2448 This property is not effective for all spanners. For example,
2449 seting it to @code{#t} has no effect on slurs or phrasing slurs
2450 or on other spanners for which terminating on the bar line would
2453 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2455 Objects which support the @code{line-spanner-interface} include
2458 @item @code{DynamicTextSpanner}
2459 @item @code{Glissando}
2460 @item @code{TextSpanner}
2461 @item @code{TrillSpanner}
2462 @item @code{VoiceFollower}
2465 The routine responsible for drawing the stencils for these spanners is
2466 @code{ly:line-interface::print}. This routine determines the
2467 exact location of the two end points and draws a line
2468 between them, in the style requested. The locations of the two
2469 end points of the spanner are computed on-the-fly, but it is
2470 possible to override their Y-coordinates. The
2471 properties which need to be specified are nested
2472 two levels down within the property hierarchy, but the syntax of
2473 the @code{\override} command is quite simple:
2475 @lilypond[relative=2,quote,verbatim]
2477 \once \override Glissando #'(bound-details left Y) = #3
2478 \once \override Glissando #'(bound-details right Y) = #-2
2482 The units for the @code{Y} property are @code{staff-space}s,
2483 with the center line of the staff being the zero point.
2484 For the glissando, this is the value for @code{Y} at the
2485 X-coordinate corresponding to the center point of each note head,
2486 if the line is imagined to be extended to there.
2488 If @code{Y} is not set, the value is computed from the vertical
2489 position of the corresponding attachment point of the spanner.
2491 In case of a line break, the values for the end points are
2492 specified by the @code{left-broken} and @code{right-broken}
2493 sub-lists of @code{bound-details}. For example:
2495 @lilypond[relative=2,ragged-right,verbatim,fragment]
2496 \override Glissando #'breakable = ##t
2497 \override Glissando #'(bound-details right-broken Y) = #-3
2498 c1 \glissando \break
2503 A number of further properties of the @code{left} and
2504 @code{right} sub-lists of the @code{bound-details} property
2505 may be modified in the same way as @code{Y}:
2509 This sets the Y-coordinate of the end point, in @code{staff-space}s
2510 offset from the staff center line. By default, it is the center of
2511 the bound object, so a glissando points to the vertical center of
2514 For horizontal spanners, such as text spanners and trill spanners,
2515 it is hardcoded to 0.
2518 This determines where the line starts and ends in the X-direction,
2519 relative to the bound object. So, a value of @code{-1} (or
2520 @code{LEFT}) makes the line start/end at the left side of the note
2521 head it is attached to.
2524 This is the absolute X-coordinate of the end point. It is usually
2525 computed on the fly, and overriding it has little useful effect.
2528 Line spanners may have symbols at the beginning or end, which is
2529 contained in this sub-property. This is for internal use; it is
2530 recommended that @code{text} be used instead.
2533 This is a markup that is evaluated to yield the stencil. It is used
2534 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2536 @lilypond[quote,ragged-right,fragment,relative=2,verbatim]
2537 \override TextSpanner #'(bound-details left text)
2538 = \markup { \small \bold Slower }
2539 c2\startTextSpan b c a\stopTextSpan
2542 @item stencil-align-dir-y
2543 @item stencil-offset
2544 Without setting one of these, the stencil is simply put at the
2545 end-point, centered on the line, as defined by the @code{X} and
2546 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2547 or @code{stencil-offset} will move the symbol at the edge vertically
2548 relative to the end point of the line:
2550 @lilypond[relative=1,fragment,verbatim]
2551 \override TextSpanner
2552 #'(bound-details left stencil-align-dir-y) = #-2
2553 \override TextSpanner
2554 #'(bound-details right stencil-align-dir-y) = #UP
2556 \override TextSpanner
2557 #'(bound-details left text) = #"ggg"
2558 \override TextSpanner
2559 #'(bound-details right text) = #"hhh"
2560 c4^\startTextSpan c c c \stopTextSpan
2563 Note that negative values move the text @emph{up}, contrary to the
2564 effect that might be expected, as a value of @code{-1} or
2565 @code{DOWN} means align the @emph{bottom} edge of the text with
2566 the spanner line. A value of @code{1} or @code{UP} aligns
2567 the top edge of the text with the spanner line.
2570 Setting this sub-property to @code{#t} produces an arrowhead at the
2574 This sub-property controls the space between the specified
2575 end point of the line and the actual end. Without padding, a
2576 glissando would start and end in the center of each note head.
2580 The music function @code{\endSpanners} terminates the spanner
2581 which starts on the immediately following note prematurely. It
2582 is terminated after exactly one note, or at the following bar line
2583 if @code{to-barline} is true and a bar line occurs before the next
2586 @lilypond[verbatim,quote,ragged-right,relative=2,fragment]
2588 c2 \startTextSpan c2 c2
2593 When using @code{\endSpanners} it is not necessary to close
2594 \startTextSpan with \stopTextSpan, nor is it necessary to close
2595 hairpins with @code{\!}.
2599 Internals Reference:
2600 @rinternals{TextSpanner},
2601 @rinternals{Glissando},
2602 @rinternals{VoiceFollower},
2603 @rinternals{TrillSpanner},
2604 @rinternals{line-spanner-interface}.
2607 @node Visibility of objects
2608 @subsection Visibility of objects
2610 @cindex objects, visibility of
2611 @cindex grobs, visibility of
2612 @cindex visibility of objects
2614 There are four main ways in which the visibility of layout objects
2615 can be controlled: their stencil can be removed, they can be made
2616 transparent, they can be colored white, or their
2617 @code{break-visibility} property can be overridden. The first
2618 three apply to all layout objects; the last to just a few -- the
2619 @emph{breakable} objects. The Learning Manual introduces these
2620 four techniques, see @rlearning{Visibility and color of objects}.
2622 There are also a few other techniques which are specific to
2623 certain layout objects. These are covered under Special
2627 * Removing the stencil::
2628 * Making objects transparent::
2629 * Painting objects white::
2630 * Using break-visibility::
2631 * Special considerations::
2635 @node Removing the stencil
2636 @unnumberedsubsubsec Removing the stencil
2638 @cindex stencil, removing
2640 Every layout object has a stencil property. By default this is set
2641 to the specific function which draws that object. If this property
2642 is overridden to @code{#f} no function will be called and the object
2643 will not be drawn. The default action can be recovered with
2646 @lilypond[quote,verbatim,relative=1]
2648 \override Score.BarLine #'stencil = ##f
2650 \revert Score.BarLine #'stencil
2654 @node Making objects transparent
2655 @unnumberedsubsubsec Making objects transparent
2657 @cindex transparent, making objects
2659 Every layout object has a transparent property which by default is
2660 set to @code{#f}. If set to @code{#t} the object still occupies
2661 space but is made invisible.
2663 @lilypond[quote,verbatim,relative=2]
2665 \once \override NoteHead #'transparent = ##t
2669 @node Painting objects white
2670 @unnumberedsubsubsec Painting objects white
2672 @cindex objects, coloring
2673 @cindex coloring objects
2675 @cindex printing order
2676 @cindex overwriting objects
2677 @cindex objects, overwriting
2678 @cindex grobs, overwriting
2680 Every layout object has a color property which by default is set
2681 to @code{black}. If this is overridden to @code{white} the object
2682 will be indistinguishable from the white background. However,
2683 if the object crosses other objects the color of the crossing
2684 points will be determined by the order in which they are drawn,
2685 and this may leave a ghostly image of the white object, as shown
2688 @lilypond[quote,verbatim,relative=2]
2689 \override Staff.Clef #'color = #white
2693 This may be avoided by changing the order of printing the objects.
2694 All layout objects have a @code{layer} property which should be set
2695 to an integer. Objects with the lowest value of @code{layer} are
2696 drawn first, then objects with progressively higher values are drawn,
2697 so objects with higher values overwrite objects with lower values.
2698 By default most objects are assigned a @code{layer} value of
2699 @code{1}, although a few objects, including @code{StaffSymbol} and
2700 @code{BarLine}, are assigned a value of @code{0}. The order of
2701 printing objects with the same value of @code{layer} is indeterminate.
2703 In the example above the white clef, with a default @code{layer}
2704 value of @code{1}, is drawn after the staff lines (default
2705 @code{layer} value @code{0}), so overwriting them. To change this,
2706 the @code{Clef} object must be given in a lower value of
2707 @code{layer}, say @code{-1}, so that it is drawn earlier:
2709 @lilypond[quote,verbatim,relative=2]
2710 \override Staff.Clef #'color = #white
2711 \override Staff.Clef #'layer = #-1
2715 @node Using break-visibility
2716 @unnumberedsubsubsec Using break-visibility
2718 @c TODO Add making other objects breakable
2720 @cindex break-visibility
2722 Most layout objects are printed only once, but some like
2723 bar lines, clefs, time signatures and key signatures, may need
2724 to be printed twice when a line break occurs -- once at the end
2725 of the line and again at the start of the next line. Such
2726 objects are called @emph{breakable}, and have a property, the
2727 @code{break-visibility} property to control their visibility
2728 at the three positions in which they may appear -- at the
2729 start of a line, within a line if they are changed, and at the
2730 end of a line if a change takes place there.
2732 For example, the time signature
2733 by default will be printed at the start of the first line, but
2734 nowhere else unless it changes, when it will be printed at the
2735 point at which the change occurs. If this change occurs at the
2736 end of a line the new time signature will be printed at the start
2737 of the next line and a cautionary time signature will be printed
2738 at the end of the previous line as well.
2740 This behaviour is controlled by the @code{break-visibility}
2741 property, which is explained in
2742 @c Leave this ref on a newline - formats incorrectly otherwise -td
2743 @rlearning{Visibility and color of objects}. This property takes
2744 a vector of three booleans which, in order, determine whether the
2745 object is printed at the end of, within the body of, or at the
2746 beginning of a line. Or to be more precise, before a line break,
2747 where there is no line break, or after a line break.
2749 Alternatively, these eight combinations may be specified
2750 by pre-defined functions, defined in @file{scm/@/output@/-lib@/.scm},
2751 where the last three columns indicate whether the layout objects
2752 will be visible in the positions shown at the head of the columns:
2754 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2755 @headitem Function @tab Vector @tab Before @tab At no @tab After
2756 @headitem form @tab form @tab break @tab break @tab break
2758 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2759 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2760 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2761 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2762 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2763 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2764 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2765 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2768 The default settings of @code{break-visibility} depend on the
2769 layout object. The following table shows all the layout objects
2770 of interest which are affected by @code{break-visibility} and the
2771 default setting of this property:
2773 @multitable @columnfractions .3 .3 .4
2775 @headitem Layout object @tab Usual context @tab Default setting
2777 @c omit Ambitus as it appears not to be affected by break-visibility -td
2778 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2779 @item @code{BarLine} @tab @code{Score} @tab calculated
2780 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2781 @c omit the following item until it can be explained -td
2782 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2783 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2784 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2785 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2786 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2787 @c omit KeyCancellation until it can be explained -td
2788 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2789 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2790 @c omit LeftEdge until it can be explained -td
2791 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2792 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2793 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2794 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2798 The example below shows the use of the vector form to control the
2799 visibility of barlines:
2801 @lilypond[quote,verbatim,relative=1,ragged-right]
2804 % Remove bar line at the end of the current line
2805 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2811 Although all three components of the vector used to override
2812 @code{break-visibility} must be present, not all of them are
2813 effective with every layout object, and some combinations may
2814 even give errors. The following limitations apply:
2817 @item Bar lines cannot be printed at start of line.
2818 @item A bar number cannot be printed at the start of the first
2819 line unless it is set to be different from 1.
2820 @item Clef -- see below
2821 @item Double percent repeats are either all printed or all
2822 suppressed. Use begin-of line-invisible to print and
2823 all-invisible to suppress.
2824 @item Key signature -- see below
2825 @item OctavateEight -- see below
2828 @node Special considerations
2829 @unnumberedsubsubsec Special considerations
2831 @strong{@emph{Visibility following explicit changes}}
2833 @cindex key signature, visibility following explicit change
2834 @cindex explicitKeySignatureVisibility
2835 @cindex clef, visibility following explicit change
2836 @cindex explicitClefVisibility
2838 The @code{break-visibility} property controls the visibility of
2839 key signatures and changes of clef only at the start of lines,
2840 i.e. after a break. It has no effect on the visibility of the
2841 key signature or clef following an explicit key change or an
2842 explicit clef change within or at the end of a line. In the
2843 following example the key signature following the explicit change
2844 to B-flat major is still visible, even though @code{all-invisible}
2847 @lilypond[quote,verbatim,relative=1,ragged-right]
2850 % Try to remove all key signatures
2851 \override Staff.KeySignature #'break-visibility = #all-invisible
2859 The visibility of such explicit key signature and clef changes is
2860 controlled by the @code{explicitKeySignatureVisibility} and
2861 @code{explicitClefVisibility} properties. These are the equivalent
2862 of the @code{break-visibility} property and both take a vector of
2863 three booleans or the predefined functions listed above, exactly like
2864 @code{break-visibility}. Both are properties of the Staff context,
2865 not the layout objects themselves, and so they are set using the
2866 @code{\set} command. Both are set by default to @code{all-visible}.
2867 These properties control only the visibility of key signatures and
2868 clefs resulting from explicit changes and do not affect key
2869 signatures and clefs at the beginning of lines;
2870 @code{break-visibility} must still be overridden in the appropriate
2871 object to remove these.
2873 @lilypond[quote,verbatim,relative=1,ragged-right]
2876 \set Staff.explicitKeySignatureVisibility = #all-invisible
2877 \override Staff.KeySignature #'break-visibility = #all-invisible
2884 @strong{@emph{Visibility of cautionary accidentals}}
2886 To remove the cautionary accidentals printed at an explicit key
2887 change, set the Staff context property @code{printKeyCancellation}
2890 @lilypond[quote,verbatim,relative=1,ragged-right]
2893 \set Staff.explicitKeySignatureVisibility = #all-invisible
2894 \set Staff.printKeyCancellation = ##f
2895 \override Staff.KeySignature #'break-visibility = #all-invisible
2902 With these overrides only the accidentals before the notes remain
2903 to indicate the change of key.
2905 @c TODO Add visibility of cautionary accidentals before notes
2907 @strong{@emph{Automatic bars}}
2909 @cindex automaticBars
2910 @cindex bar lines, suppressing
2912 As a special case, the printing of bar lines can also be turned off
2913 by setting the @code{automaticBars} property in the Score context.
2914 If set to @code{#f}, bar lines will not be printed automatically;
2915 they must be explicitly created with a @code{\bar} command. Unlike
2916 the @code{\cadenzaOn} predefined command, measures are still counted.
2917 Bar generation will resume according to that count if this property
2918 is later set to @code{#t}. When set to @code{#f}, line breaks can
2919 occur only at explicit @code{\bar} commands.
2923 @strong{@emph{Octavated clefs}}
2925 @cindex octavated clefs, visibility of
2926 @cindex visibility of octavated clefs
2927 @cindex clefs, visibility of octavation
2929 The small octavation symbol on octavated clefs is produced by the
2930 @code{OctavateEight} layout object. Its visibility is controlled
2931 independently from that of the @code{Clef} object, so it is
2932 necessary to apply any required @code{break-visibility} overrides
2933 to both the @code{Clef} and the @code{OctavateEight} layout objects
2934 to fully suppress such clef symbols at the start of each line.
2936 For explicit clef changes, the @code{explicitClefVisibility}
2937 property controls both the clef symbol and any octavation symbol
2943 @rlearning{Visibility and color of objects}
2947 @subsection Line styles
2949 Some performance indications, e.g., @i{rallentando} and
2950 @i{accelerando} and @i{trills} are written as text and are
2951 extended over many measures with lines, sometimes dotted or wavy.
2953 These all use the same routines as the glissando for drawing the
2954 texts and the lines, and tuning their behavior is therefore also
2955 done in the same way. It is done with a spanner, and the routine
2956 responsible for drawing the spanners is
2957 @code{ly:line-interface::print}. This routine determines the
2958 exact location of the two @i{span points} and draws a line
2959 between them, in the style requested.
2961 Here is an example showing the different line styles available,
2962 and how to tune them.
2964 @lilypond[relative=2,ragged-right,verbatim,fragment]
2966 \once \override Glissando #'style = #'dashed-line
2968 \override Glissando #'style = #'dotted-line
2970 \override Glissando #'style = #'zigzag
2972 \override Glissando #'style = #'trill
2976 The locations of the end-points of the spanner are computed
2977 on-the-fly for every graphic object, but it is possible to
2981 @lilypond[relative=2,ragged-right,verbatim,fragment]
2983 \once \override Glissando #'(bound-details right Y) = #-2
2987 The value for @code{Y} is set to @code{-2} for the right end
2988 point. The left side may be similarly adjusted by specifying
2989 @code{left} instead of @code{right}.
2991 If @code{Y} is not set, the value is computed from the vertical
2992 position of the left and right attachment points of the spanner.
2994 Other adjustments of spanners are possible, for details, see
2997 @node Rotating objects
2998 @subsection Rotating objects
3000 Both layout objects and elements of markup text can be rotated by
3001 any angle about any point, but the method of doing so differs.
3004 * Rotating layout objects::
3008 @node Rotating layout objects
3009 @unnumberedsubsubsec Rotating layout objects
3011 @cindex rotating objects
3012 @cindex objects, rotating
3014 All layout objects which support the @code{grob-interface} can be
3015 rotated by setting their @code{rotation} property. This takes a
3016 list of three items: the angle of rotation counter-clockwise,
3017 and the x and y coordinates of the point relative to the object's
3018 reference point about which the rotation is to be performed. The
3019 angle of rotation is specified in degrees and the coordinates in
3022 The angle of rotation and the coordinates of the rotation point must
3023 be determined by trial and error.
3025 @cindex hairpins, angled
3026 @cindex angled hairpins
3028 There are only a few situations where the rotation of layout
3029 objects is useful; the following example shows one situation where
3032 @lilypond[quote,verbatim,relative=1]
3034 \override Hairpin #'rotation = #'(20 -1 0)
3038 @node Rotating markup
3039 @unnumberedsubsubsec Rotating markup
3041 All markup text can be rotated to lie at any angle by prefixing it
3042 with the @code{\rotate} command. The command takes two arguments:
3043 the angle of rotation in degrees counter-clockwise and the text to
3044 be rotated. The extents of the text are not rotated: they take
3045 their values from the extremes of the x and y coordinates of the
3046 rotated text. In the following example the
3047 @code{outside-staff-priority} property for text is set to @code{#f}
3048 to disable the automatic collision avoidance, which would push some
3049 of the text too high.
3051 @lilypond[quote,verbatim,relative=1]
3052 \override TextScript #'outside-staff-priority = ##f
3053 g4^\markup { \rotate #30 "a G" }
3054 b^\markup { \rotate #30 "a B" }
3055 des^\markup { \rotate #30 "a D-Flat" }
3056 fis^\markup { \rotate #30 "an F-Sharp" }
3059 @node Advanced tweaks
3060 @section Advanced tweaks
3062 This section discusses various approaches to fine tuning the
3063 appearance of the printed score.
3066 * Aligning objects::
3067 * Vertical grouping of grobs::
3068 * Modifying stencils::
3069 * Modifying shapes::
3075 @rlearning{Tweaking output},
3076 @rlearning{Other sources of information}.
3079 @ref{Explaining the Internals Reference},
3080 @ref{Modifying properties},
3083 @file{scm/@/define@/-grobs@/.scm}.
3086 @rlsr{Tweaks and overrides}.
3089 @rextend{Interfaces for programmers}.
3091 Internals Reference:
3092 @rinternals{All layout objects}.
3095 @node Aligning objects
3096 @subsection Aligning objects
3098 Graphical objects which support the @code{self-alignment-interface} and/or
3099 the @code{side-position-interface} can be
3100 aligned to a previously placed object in a variety of ways. For a list of these objects, see
3101 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
3103 All graphical objects have a reference point, a horizontal extent and a
3104 vertical extent. The horizontal extent is a pair of numbers
3105 giving the displacements from the reference point of the left and
3106 right edges, displacements to the left being negative. The
3107 vertical extent is a pair of numbers giving the displacement from
3108 the reference point to the bottom and top edges, displacements down
3111 An object's position on a staff is given by the values of the
3112 @code{X-offset} and @code{Y-offset} properties. The value of
3113 @code{X-offset} gives the displacement from the x coordinate of
3114 the reference point of the parent object, and the value of
3115 @code{Y-offset} gives the displacement from the center line of the
3116 staff. The values of @code{X-offset} and
3117 @code{Y-offset} may be set directly or may be set to be calculated
3118 by procedures in order to achieve alignment with the parent object
3121 @warning{Many objects have special positioning considerations which
3122 cause any setting of @code{X-offset} or @code{Y-offset} to be
3123 ignored or modified, even though the object supports the
3124 @code{self-alignment-interface}.}
3126 For example, an accidental can be repositioned
3127 vertically by setting @code{Y-offset} but any changes to
3128 @code{X-offset} have no effect.
3130 Rehearsal marks may be aligned with
3131 breakable objects such as bar lines, clef symbols, time signature
3132 symbols and key signatures. There are special properties to be
3133 found in the @code{break-aligned-interface} for positioning rehearsal
3134 marks on such objects.
3137 * Setting @code{X-offset} and @code{Y-offset} directly::
3138 * Using the @code{side-position-interface}::
3139 * Using the @code{self-alignment-interface}::
3140 * Using the @code{break-alignable-interface}::
3143 @node Setting @code{X-offset} and @code{Y-offset} directly
3144 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
3146 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
3147 properties of many objects. The following example shows three
3148 notes with the default fingering position and the positions with @code{X-offset}
3149 and @code{Y-offset} modified.
3151 @lilypond[verbatim,quote,relative=2]
3154 -\tweak #'X-offset #0
3155 -\tweak #'Y-offset #0
3158 -\tweak #'X-offset #-1
3159 -\tweak #'Y-offset #1
3165 @node Using the @code{side-position-interface}
3166 @unnumberedsubsubsec Using the @code{side-position-interface}
3168 An object which supports the @code{side-position-interface} can be
3169 placed next to its parent object so that
3170 the specified edges of the two objects touch. The object may be
3171 placed above, below, to the right or to the left of the parent.
3172 The parent cannot be specified; it is determined by the order of
3173 elements in the input stream. Most objects have the associated
3174 note head as their parent.
3176 The values of the @code{side-axis} and @code{direction} properties
3177 determine where the object is to be placed, as follows:
3179 @c TODO add an example of each to the table
3181 @multitable @columnfractions .3 .3 .3
3182 @headitem @code{side-axis} @tab @code{direction} @tab
3183 @headitem property @tab property @tab Placement
3185 @item @code{0} @tab @code{-1} @tab left
3186 @item @code{0} @tab @code{1} @tab right
3187 @item @code{1} @tab @code{-1} @tab below
3188 @item @code{1} @tab @code{1} @tab above
3192 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
3193 the procedure @code{ly:side-position-interface::x-aligned-side}.
3194 This procedure will return the correct value of @code{X-offset} to
3195 place the object to the left or right side of the parent according
3196 to value of @code{direction}.
3198 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3199 the procedure @code{ly:side-position-interface::y-aligned-side}.
3200 This procedure will return the correct value of @code{Y-offset} to
3201 place the object to the top or bottom of the parent according
3202 to value of @code{direction}.
3204 @c TODO Add examples
3206 @node Using the @code{self-alignment-interface}
3207 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3209 @emph{Self-aligning objects horizontally}
3211 The horizontal alignment of an object which supports the
3212 @code{self-alignment-interface} is controlled by the value of
3213 the @code{self-alignment-X} property, provided the object's
3214 @code{X-offset} property is set to
3215 @code{ly:self-alignment-interface::x-aligned-on-self}.
3216 @code{self-alignment-X} may be given any
3217 real value, in units of half the total X extent of the
3218 object. Negative values move the object to the right, positive
3219 to the left. A value of @code{0} centers the object on the
3220 reference point of its parent, a value of @code{-1} aligns the
3221 left edge of the object on the reference point of its parent,
3222 and a value of @code{1} aligns the right edge of the object on the
3223 reference point of its parent. The symbols @code{LEFT},
3224 @code{CENTER} and @code{RIGHT} may be used instead of the values
3225 @code{-1, 0, 1} respectively.
3227 Normally the @code{\override} command would be used to modify the
3228 value of @code{self-alignment-X}, but the @code{\tweak} command
3229 can be used to separately align several annotations on a single
3232 @lilypond[quote,verbatim,relative=1]
3234 -\tweak #'self-alignment-X #-1
3236 -\tweak #'self-alignment-X #0
3238 -\tweak #'self-alignment-X #RIGHT
3240 -\tweak #'self-alignment-X #-2.5
3241 ^"aligned further to the right"
3244 @emph{Self-aligning objects vertically}
3246 Objects may be aligned vertically in an analogous way to aligning
3247 them horizontally if the @code{Y-offset} property is set to
3248 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3249 other mechanisms are often involved in vertical alignment: the
3250 value of @code{Y-offset} is just one variable taken into account.
3251 This may make adjusting the value of some objects tricky.
3252 The units are just half the vertical extent of the object, which
3253 is usually quite small, so quite large numbers may be required.
3254 A value of @code{-1} aligns the lower edge of the object with
3255 the reference point of the parent object, a value of @code{0}
3256 aligns the center of the object with the reference point of the
3257 parent, and a value of @code{1} aligns the top edge of the object
3258 with the reference point of the parent. The symbols @code{DOWN},
3259 @code{CENTER}, @code{UP} may be substituted for @code{-1, 0, 1}
3262 @emph{Self-aligning objects in both directions}
3264 By setting both @code{X-offset} and @code{Y-offset}, an object may
3265 be aligned in both directions simultaneously.
3267 The following example shows how to adjust a fingering mark so
3268 that it nestles close to the note head.
3270 @lilypond[quote,verbatim,relative=2]
3272 -\tweak #'self-alignment-X #0.5 % move horizontally left
3273 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
3274 -\tweak #'self-alignment-Y #-1 % move vertically up
3279 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3281 @c Cannot document as they do not seem to operate consistently on all objects -td
3282 @c TODO investigate further
3284 The @code{aligned-on-parent} procedures are used in the same way
3285 as the @code{aligned-on-self} procedures, they difference being
3286 that they permit an object to be aligned with the @emph{edges} of
3287 the parent rather than the parent's reference point. The following
3288 example shows the difference:
3292 @lilypond[verbatim,quote]
3298 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3300 @c Cannot document as they do not seem to operate consistently on all objects -td
3301 @c TODO investigate further
3305 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3307 @node Using the @code{break-alignable-interface}
3308 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3310 @cindex align to objects
3311 @cindex break-align-symbols
3313 Rehearsal marks and bar numbers may be aligned with notation
3314 objects other than bar lines. These objects include @code{ambitus},
3315 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3316 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3317 @code{time-signature}.
3319 By default, rehearsal marks and bar numbers will be horizontally
3320 centered above the object:
3322 @lilypond[verbatim,quote,relative=1]
3324 % the RehearsalMark will be centered above the Clef
3325 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
3330 % the RehearsalMark will be centered above the TimeSignature
3331 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
3339 A list of possible target alignment objects may be specified. If
3340 some of the objects are invisible at that point due to the setting
3341 of @code{break-visibility} or the explicit visibility settings for
3342 keys and clefs, the rehearsal mark or bar number is aligned to the
3343 first object in the list which is visible. If no objects in the
3344 list are visible the object is aligned to the bar line. If the bar
3345 line is invisible the object is aligned to the place where the bar
3348 @lilypond[verbatim,quote,relative=1]
3350 % the RehearsalMark will be centered above the Key Signature
3351 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3356 % the RehearsalMark will be centered above the Clef
3357 \set Staff.explicitKeySignatureVisibility = #all-invisible
3358 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3365 The alignment of the rehearsal mark relative to the notation object
3366 can be changed, as shown in the following example. In a score with
3367 multiple staves, this setting should be done for all the staves.
3369 @lilypond[verbatim,quote,relative=1]
3370 % The RehearsalMark will be centered above the KeySignature
3371 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3377 % The RehearsalMark will be aligned with the left edge of the KeySignature
3378 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3382 % The RehearsalMark will be aligned with the right edge of the KeySignature
3383 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3389 The rehearsal mark can also be offset to the right or left of the left edge
3390 by an arbitrary amount. The units are staff-spaces:
3392 @lilypond[verbatim,quote,relative=1]
3393 % The RehearsalMark will be aligned with the left edge of the KeySignature
3394 % and then shifted right by 3.5 staff-spaces
3395 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3396 \once \override Score.KeySignature #'break-align-anchor = #3.5
3400 % The RehearsalMark will be aligned with the left edge of the KeySignature
3401 % and then shifted left by 2 staff-spaces
3402 \once \override Score.KeySignature #'break-align-anchor = #-2
3409 @node Vertical grouping of grobs
3410 @subsection Vertical grouping of grobs
3412 @c FIXME Expand this section
3414 The VerticalAlignment and VerticalAxisGroup grobs work together.
3415 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3416 etc. VerticalAlignment then vertically aligns the different grobs
3417 grouped together by VerticalAxisGroup. There is usually only one
3418 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3422 @node Modifying stencils
3423 @subsection Modifying stencils
3425 All layout objects have a @code{stencil} property which is part of
3426 the @code{grob-interface}. By default, this property is usually
3427 set to a function specific to the object that is tailor-made to
3428 render the symbol which represents it in the output. For example,
3429 the standard setting for the @code{stencil} property of the
3430 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3432 The standard symbol for any object can be replaced by modifying the
3433 @code{stencil} property to reference a different, specially-written,
3434 procedure. This requires a high level of knowledge of the internal
3435 workings of LilyPond, but there is an easier way which can often
3436 produce adequate results.
3438 This is to set the @code{stencil} property to the procedure which
3439 prints text -- @code{ly:text-interface::print} -- and to add a
3440 @code{text} property to the object which is set to contain the
3441 markup text which produces the required symbol. Due to the
3442 flexibility of markup, much can be achieved -- see in particular
3443 @ref{Graphic notation inside markup}.
3445 The following example demonstrates this by changing the note head
3446 symbol to a cross within a circle.
3448 @lilypond[verbatim,quote]
3450 \once \override NoteHead #'stencil = #ly:text-interface::print
3451 \once \override NoteHead #'text = \markup {
3453 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3454 \musicglyph #"noteheads.s2cross"
3462 Any of the glyphs in the feta Font can be supplied to the
3463 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3465 @c TODO Add inserting eps files or ref to later
3467 @c TODO Add inserting Postscript or ref to later
3472 @ref{Graphic notation inside markup},
3473 @ref{Formatting text},
3474 @ref{Text markup commands},
3475 @ref{The Feta font}.
3478 @node Modifying shapes
3479 @subsection Modifying shapes
3482 * Modifying ties and slurs::
3485 @node Modifying ties and slurs
3486 @unnumberedsubsubsec Modifying ties and slurs
3488 @cindex slurs, modifying
3489 @cindex ties, modifying
3490 @cindex Bézier curves
3491 @cindex Bézier control points
3493 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3494 curves. If the shape of the tie or slur which is calculated
3495 automatically is not optimum, the shape may be modified manually by
3496 explicitly specifying the four control points required to define
3497 a third-order Bézier curve.
3499 Third-order or cubic Bézier curves are defined by four control
3500 points. The first and fourth control points are precisely the
3501 starting and ending points of the curve. The intermediate two
3502 control points define the shape. Animations showing how the curve
3503 is drawn can be found on the web, but the following description
3504 may be helpful. The curve starts from the first control point
3505 heading directly towards the second, gradually bending over to
3506 head towards the third and continuing to bend over to head towards
3507 the fourth, arriving there travelling directly from the third
3508 control point. The curve is entirely contained in the
3509 quadrilateral defined by the four control points.
3511 Here is an example of a case where the tie is not optimum, and
3512 where @code{\tieDown} would not help.
3514 @lilypond[verbatim,quote,relative=1]
3518 { r4 <g c,> <g c,> <g c,> }
3522 One way of improving this tie is to manually modify its control
3525 The coordinates of the Bézier control points are specified in units
3526 of staff-spaces. The X@tie{}coordinate is relative to the reference
3527 point of the note to which the tie or slur is attached, and the
3528 Y@tie{}coordinate is relative to the staff center line. The
3529 coordinates are entered as a list of four pairs of decimal numbers
3530 (reals). One approach is to estimate the coordinates of the two
3531 end points, and then guess the two intermediate points. The optimum
3532 values are then found by trial and error.
3534 It is useful to remember that a symmetric curve requires symmetric
3535 control points, and that Bézier curves have the useful property that
3536 transformations of the curve such as translation, rotation and
3537 scaling can be achieved by applying the same transformation to the
3538 curve's control points.
3540 For the example above the following override gives a satisfactory
3541 tie. Note the placement -- it has to be immediately before the note
3542 to which the start of the tie (or slur) is attached.
3544 @lilypond[verbatim,quote,relative=1]
3548 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3552 { r4 <g c,> <g c,> <g c,>4 }
3558 It is not possible to modify shapes of ties or slurs by changing
3559 the @code{control-points} property if there are more than one at
3560 the same musical moment, not even by using the @code{\tweak}