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
7 version that you are working on. See TRANSLATION for details.
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{@rlearning{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 @ref{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 Specific contexts, like @code{Staff} and @code{Voice}, are made of
748 simple building blocks. It is possible to create new types of
749 contexts with different combinations of engraver plug-ins.
751 The next example shows how to build a different type of
752 @code{Voice} context from scratch. It will be similar to
753 @code{Voice}, but only prints centered slash note heads. It can be used
754 to indicate improvisation in jazz pieces,
756 @lilypond[quote,ragged-right]
759 \type "Engraver_group"
760 \consists "Note_heads_engraver"
761 \consists "Rhythmic_column_engraver"
762 \consists "Text_engraver"
763 \consists Pitch_squash_engraver
764 squashedPosition = #0
765 \override NoteHead #'style = #'slash
766 \override Stem #'transparent = ##t
770 \accepts "ImproVoice"
774 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
775 c4 c^"undress" c_"while playing :)" c }
781 These settings are defined within a @code{\context} block inside a
782 @code{\layout} block,
792 In the following discussion, the example input shown should go in place
793 of the @dots{} in the previous fragment.
795 First it is necessary to define a name for the new context:
801 Since it is similar to the @code{Voice}, we want commands that work
802 on (existing) @code{Voice}s to remain working. This is achieved by
803 giving the new context an alias @code{Voice},
809 The context will print notes and instructive texts, so we need to add
810 the engravers which provide this functionality,
813 \consists Note_heads_engraver
814 \consists Text_engraver
817 but we only need this on the center line,
820 \consists Pitch_squash_engraver
821 squashedPosition = #0
824 The @rinternals{Pitch_squash_engraver} modifies note heads (created
825 by @rinternals{Note_heads_engraver}) and sets their vertical
826 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
829 The notes look like a slash, and have no stem,
832 \override NoteHead #'style = #'slash
833 \override Stem #'transparent = ##t
836 All these plug-ins have to cooperate, and this is achieved with a
837 special plug-in, which must be marked with the keyword @code{\type}.
838 This should always be @code{Engraver_group}.
841 \type "Engraver_group"
849 \type "Engraver_group"
850 \consists "Note_heads_engraver"
851 \consists "Text_engraver"
852 \consists Pitch_squash_engraver
853 squashedPosition = #0
854 \override NoteHead #'style = #'slash
855 \override Stem #'transparent = ##t
861 Contexts form hierarchies. We want to hang the @code{ImproVoice}
862 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
863 modify the @code{Staff} definition with the @code{\accepts}
874 The opposite of @code{\accepts} is @code{\denies},
875 which is sometimes needed when reusing existing context definitions.
877 Putting both into a @code{\layout} block, like
887 \accepts "ImproVoice"
892 Then the output at the start of this subsection can be entered as
900 c c_"while playing :)"
907 @node Aligning contexts
908 @subsection Aligning contexts
910 New contexts may be aligned above or below existing contexts. This
911 could be useful in setting up a vocal staff (@rlearning{Vocal ensembles}) and
914 @c TODO Better example needed. Ref LM, and expand on it.
917 @funindex alignAboveContext
918 @funindex alignBelowContext
920 @lilypond[quote,ragged-right]
923 \relative c' \new Staff = "main" {
926 \new Staff \with { alignAboveContext = #"main" } \ossia
933 @cindex nested contexts
934 @cindex contexts, nested
939 Contexts like @code{PianoStaff} can contain other contexts
940 nested within them. Contexts which are acceptable for nesting
941 are defined by the @qq{accepts} list of a context. Contexts
942 which are not in this list are placed below the outer context
943 in the printed score.
944 For example, the @code{PianoStaff} context is defined by default
945 to accept @code{Staff} and @code{FiguredBass} contexts within
946 it, but not (for example) a @code{Lyrics} context. So in the
947 following structure the lyrics are placed below the piano staff
948 rather than between the two staves:
950 @lilypond[verbatim,quote,relative=1]
953 \new Staff { e4 d c2 }
954 \addlyrics { Three blind mice }
962 The @qq{accepts} list of a context can be modified to include
963 additional nested contexts, so if we wanted the lyrics to appear
964 between the two staves we could use:
966 @lilypond[verbatim,quote,relative=1]
967 \new PianoStaff \with { \accepts Lyrics }
969 \new Staff { e4 d c2 }
970 \addlyrics { Three blind mice }
978 The opposite of @code{\accepts} is @code{\denies}; this removes a
979 context from the @qq{accepts} list.
981 @node Explaining the Internals Reference
982 @section Explaining the Internals Reference
986 * Navigating the program reference::
987 * Layout interfaces::
988 * Determining the grob property::
989 * Naming conventions::
992 @node Navigating the program reference
993 @subsection Navigating the program reference
995 @c TODO remove this (it's in the LM)
996 @c Replace with more factual directions
998 Suppose we want to move the fingering indication in the fragment
1001 @lilypond[quote,fragment,relative=2,verbatim]
1007 If you visit the documentation on fingering instructions (in
1008 @ref{Fingering instructions}), you will notice:
1013 Internals Reference: @rinternals{Fingering}.
1018 @c outdated info; probably will delete.
1020 This fragment points to two parts of the program reference: a page
1021 on @code{FingeringEvent} and one on @code{Fingering}.
1023 The page on @code{FingeringEvent} describes the properties of the music
1024 expression for the input @code{-2}. The page contains many links
1025 forward. For example, it says
1028 Accepted by: @rinternals{Fingering_engraver},
1032 That link brings us to the documentation for the Engraver, the
1036 This engraver creates the following layout objects: @rinternals{Fingering}.
1039 In other words, once the @code{FingeringEvent}s are interpreted, the
1040 @code{Fingering_engraver} plug-in will process them.
1044 @c I can't figure out what this is supposed to mean. -gp
1046 The @code{Fingering_engraver} is also listed to create
1047 @rinternals{Fingering} objects,
1049 @c old info? it doesn't make any sense to me with our current docs.
1051 second bit of information listed under @b{See also} in the Notation
1056 The programmer's reference is available as an HTML document. It is
1057 highly recommended that you read it in HTML form, either online or
1058 by downloading the HTML documentation. This section will be much more
1059 difficult to understand if you are using the
1063 Follow the link to @rinternals{Fingering}. At the top of the
1067 Fingering objects are created by: @rinternals{Fingering_engraver} and
1068 @rinternals{New_fingering_engraver}.
1071 By following related links inside the program reference, we can follow the
1072 flow of information within the program:
1076 @item @rinternals{Fingering}:
1077 @rinternals{Fingering} objects are created by:
1078 @rinternals{Fingering_engraver}
1080 @item @rinternals{Fingering_engraver}:
1081 Music types accepted: @rinternals{fingering-event}
1083 @item @rinternals{fingering-event}:
1084 Music event type @code{fingering-event} is in Music expressions named
1085 @rinternals{FingeringEvent}
1088 This path goes against the flow of information in the program: it
1089 starts from the output, and ends at the input event. You could
1090 also start at an input event, and read with the flow of
1091 information, eventually ending up at the output object(s).
1093 The program reference can also be browsed like a normal document. It
1094 contains chapters on
1096 @rinternals{Music definitions},
1099 @code{Music definitions}
1101 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1102 chapter lists all the definitions used and all properties that may be
1106 @node Layout interfaces
1107 @subsection Layout interfaces
1109 @cindex interface, layout
1110 @cindex layout interface
1113 The HTML page that we found in the previous section describes the
1114 layout object called @rinternals{Fingering}. Such an object is a
1115 symbol within the score. It has properties that store numbers (like
1116 thicknesses and directions), but also pointers to related objects. A
1117 layout object is also called a @emph{Grob}, which is short for Graphical
1118 Object. For more details about Grobs, see @rinternals{grob-interface}.
1120 The page for @code{Fingering} lists the definitions for the
1121 @code{Fingering} object. For example, the page says
1124 @code{padding} (dimension, in staff space):
1130 which means that the number will be kept at a distance of at least 0.5
1134 Each layout object may have several functions as a notational or
1135 typographical element. For example, the Fingering object
1136 has the following aspects
1140 Its size is independent of the horizontal spacing, unlike slurs or beams.
1143 It is a piece of text. Granted, it is usually a very short text.
1146 That piece of text is typeset with a font, unlike slurs or beams.
1149 Horizontally, the center of the symbol should be aligned to the
1150 center of the note head.
1153 Vertically, the symbol is placed next to the note and the staff.
1156 The vertical position is also coordinated with other superscript
1157 and subscript symbols.
1160 Each of these aspects is captured in so-called @emph{interface}s,
1161 which are listed on the @rinternals{Fingering} page at the bottom
1164 This object supports the following interfaces:
1165 @rinternals{item-interface},
1166 @rinternals{self-alignment-interface},
1167 @rinternals{side-position-interface}, @rinternals{text-interface},
1168 @rinternals{text-script-interface}, @rinternals{font-interface},
1169 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1172 Clicking any of the links will take you to the page of the respective
1173 object interface. Each interface has a number of properties. Some of
1174 them are not user-serviceable (@q{Internal properties}), but others
1177 We have been talking of @emph{the} @code{Fingering} object, but actually it
1178 does not amount to much. The initialization file (see
1179 @rlearning{Other sources of information})
1180 @file{scm/@/define@/-grobs@/.scm} shows the soul of the @q{object},
1185 (avoid-slur . around)
1186 (slur-padding . 0.2)
1187 (staff-padding . 0.5)
1188 (self-alignment-X . 0)
1189 (self-alignment-Y . 0)
1190 (script-priority . 100)
1191 (stencil . ,ly:text-interface::print)
1192 (direction . ,ly:script-interface::calc-direction)
1193 (font-encoding . fetaNumber)
1194 (font-size . -5) ; don't overlap when next to heads.
1195 (meta . ((class . Item)
1196 (interfaces . (finger-interface
1198 text-script-interface
1200 side-position-interface
1201 self-alignment-interface
1202 item-interface))))))
1206 As you can see, the @code{Fingering} object is nothing more than a
1207 bunch of variable settings, and the webpage in the Internals Reference
1208 is directly generated from this definition.
1211 @node Determining the grob property
1212 @subsection Determining the grob property
1214 @c TODO remove this (it's in the LM)
1215 @c Replace with more factual directions
1217 Recall that we wanted to change the position of the @b{2} in
1219 @lilypond[quote,fragment,relative=2,verbatim]
1225 Since the @b{2} is vertically positioned next to its note, we have to
1226 meddle with the interface associated with this positioning. This is
1227 done using @code{side-position-interface}. The page for this interface
1231 @code{side-position-interface}
1233 Position a victim object (this one) next to other objects (the
1234 support). The property @code{direction} signifies where to put the
1235 victim object relative to the support (left or right, up or down?)
1240 Below this description, the variable @code{padding} is described as
1245 (dimension, in staff space)
1247 Add this much extra space between objects that are next to each other.
1251 By increasing the value of @code{padding}, we can move the
1252 fingering away from the note head. The following command inserts
1253 3 staff spaces of white
1254 between the note and the fingering:
1256 \once \override Voice.Fingering #'padding = #3
1259 Inserting this command before the Fingering object is created,
1260 i.e., before @code{c2}, yields the following result:
1262 @lilypond[quote,relative=2,fragment,verbatim]
1263 \once \override Voice.Fingering #'padding = #3
1270 In this case, the context for this tweak is @code{Voice}. This
1271 fact can also be deduced from the program reference, for the page for
1272 the @rinternals{Fingering_engraver} plug-in says
1275 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1279 @node Naming conventions
1280 @subsection Naming conventions
1282 Another thing that is needed, is an overview of the various naming
1285 scheme functions: lowercase-with-hyphens (incl. one-word
1287 scheme functions: ly:plus-scheme-style
1288 music events, music classes and music properties:
1290 Grob interfaces: scheme-style
1291 backend properties: scheme-style (but X and Y!)
1292 contexts (and MusicExpressions and grobs): Capitalized or
1294 context properties: lowercaseFollowedByCamelCase
1296 Capitalized_followed_by_lowercase_and_with_underscores
1298 Which of these are conventions and which are rules?
1299 Which are rules of the underlying language, and which are
1303 @node Modifying properties
1304 @section Modifying properties
1306 @c TODO change the menu and subsection node names to use
1307 @c backslash once the new macro to handle the refs
1308 @c is available. Need to find and change all refs at
1309 @c the same time. -td
1312 * Overview of modifying properties::
1314 * The override command::
1315 * The tweak command::
1316 * set versus override::
1320 @node Overview of modifying properties
1321 @subsection Overview of modifying properties
1323 Each context is responsible for creating certain types of graphical
1324 objects. The settings used for printing these objects are also stored by
1325 context. By changing these settings, the appearance of objects can be
1328 The syntax for this is
1331 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1334 Here @var{name} is the name of a graphical object, like
1335 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1336 variable of the formatting system (@q{grob property} or @q{layout
1337 property}). The latter is a symbol, so it must be quoted. The
1338 subsection @ref{Modifying properties}, explains what to fill in
1339 for @var{name}, @var{property}, and @var{value}. Here we only
1340 discuss the functionality of this command.
1345 \override Staff.Stem #'thickness = #4.0
1349 makes stems thicker (the default is 1.3, with staff line thickness as a
1350 unit). Since the command specifies @code{Staff} as context, it only
1351 applies to the current staff. Other staves will keep their normal
1352 appearance. Here we see the command in action:
1354 @lilypond[quote,verbatim,relative=2,fragment]
1356 \override Staff.Stem #'thickness = #4.0
1362 The @code{\override} command changes the definition of the @code{Stem}
1363 within the current @code{Staff}. After the command is interpreted
1364 all stems are thickened.
1366 Analogous to @code{\set}, the @var{context} argument may be left out,
1367 causing the default context @code{Voice} to be used. Adding
1368 @code{\once} applies the change during one timestep only.
1370 @lilypond[quote,fragment,verbatim,relative=2]
1372 \once \override Stem #'thickness = #4.0
1377 The @code{\override} must be done before the object is
1378 started. Therefore, when altering @emph{Spanner} objects such as slurs
1379 or beams, the @code{\override} command must be executed at the moment
1380 when the object is created. In this example,
1382 @lilypond[quote,fragment,verbatim,relative=2]
1383 \override Slur #'thickness = #3.0
1385 \override Beam #'thickness = #0.6
1390 the slur is fatter but the beam is not. This is because the command for
1391 @code{Beam} comes after the Beam is started, so it has no effect.
1393 Analogous to @code{\unset}, the @code{\revert} command for a context
1394 undoes an @code{\override} command; like with @code{\unset}, it only
1395 affects settings that were made in the same context. In other words, the
1396 @code{\revert} in the next example does not do anything.
1399 \override Voice.Stem #'thickness = #4.0
1400 \revert Staff.Stem #'thickness
1403 Some tweakable options are called @q{subproperties} and reside inside
1404 properties. To tweak those, use commands of the form
1406 @c leave this as a long long
1408 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1415 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1420 Internals: @rinternals{OverrideProperty}, @rinternals{RevertProperty},
1421 @rinternals{PropertySet}, @rinternals{Backend}, and
1422 @rinternals{All layout objects}.
1427 The back-end is not very strict in type-checking object properties.
1428 Cyclic references in Scheme values for properties can cause hangs
1429 or crashes, or both.
1433 @node The set command
1434 @subsection The @code{\set} command
1438 @cindex changing properties
1440 Each context can have different @emph{properties}, variables contained
1441 in that context. They can be changed during the interpretation step.
1442 This is achieved by inserting the @code{\set} command in the music,
1445 \set @var{context}.@var{prop} = #@var{value}
1449 @lilypond[quote,verbatim,relative=2,fragment]
1451 \set Score.skipBars = ##t
1455 This command skips measures that have no notes. The result is that
1456 multi-rests are condensed. The value assigned is a Scheme object. In
1457 this case, it is @code{#t}, the boolean True value.
1459 If the @var{context} argument is left out, then the current bottom-most
1460 context (typically @code{ChordNames}, @code{Voice}, or
1461 @code{Lyrics}) is used. In this example,
1463 @lilypond[quote,verbatim,relative=2,fragment]
1465 \set autoBeaming = ##f
1470 the @var{context} argument to @code{\set} is left out, so automatic
1471 beaming is switched off in the current @rinternals{Voice}. Note that
1472 the bottom-most context does not always contain the property that you
1473 wish to change -- for example, attempting to set the @code{skipBars}
1474 property (of the bottom-most context, in this case @code{Voice}) will
1477 @lilypond[quote,verbatim,relative=2,fragment]
1483 Contexts are hierarchical, so if a bigger context was specified, for
1484 example @code{Staff}, then the change would also apply to all
1485 @code{Voice}s in the current stave. The change is applied
1486 @q{on-the-fly}, during the music, so that the setting only affects the
1487 second group of eighth notes.
1491 There is also an @code{\unset} command,
1493 \unset @var{context}.@var{prop}
1497 which removes the definition of @var{prop}. This command removes
1498 the definition only if it is set in @var{context}, so
1501 \set Staff.autoBeaming = ##f
1505 introduces a property setting at @code{Staff} level. The setting also
1506 applies to the current @code{Voice}. However,
1509 \unset Voice.autoBeaming
1513 does not have any effect. To cancel this setting, the @code{\unset}
1514 must be specified on the same level as the original @code{\set}. In
1515 other words, undoing the effect of @code{Staff.autoBeaming = ##f}
1518 \unset Staff.autoBeaming
1521 Like @code{\set}, the @var{context} argument does not have to be
1522 specified for a bottom context, so the two statements
1525 \set Voice.autoBeaming = ##t
1526 \set autoBeaming = ##t
1534 Settings that should only apply to a single time-step can be entered
1535 with @code{\once}, for example in
1537 @lilypond[quote,verbatim,relative=2,fragment]
1539 \once \set fontSize = #4.7
1544 the property @code{fontSize} is unset automatically after the second
1547 A full description of all available context properties is in the
1548 program reference, see
1550 @rinternals{Tunable context properties}.
1553 Translation @expansion{} Tunable context properties.
1558 @node The override command
1559 @subsection The @code{\override} command
1561 Commands which change output generally look like
1564 \override Voice.Stem #'thickness = #3.0
1568 To construct this tweak we must determine these bits of information:
1571 @item the context: here @code{Voice}.
1572 @item the layout object: here @code{Stem}.
1573 @item the layout property: here @code{thickness}.
1574 @item a sensible value: here @code{3.0}.
1577 Some tweakable options are called @q{subproperties} and reside inside
1578 properties. To tweak those, use commands in the form
1581 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1584 @cindex internal documentation
1585 @cindex finding graphical objects
1586 @cindex graphical object descriptions
1589 @cindex internal documentation
1591 For many properties, regardless of the data type of the property, setting the
1592 property to false ( @code{##f} ) will result in turning it off, causing
1593 LilyPond to ignore that property entirely. This is particularly useful for
1594 turning off grob properties which may otherwise be causing problems.
1596 We demonstrate how to glean this information from the notation manual
1597 and the program reference.
1600 @node The tweak command
1601 @subsection The @code{\tweak} command
1606 In some cases, it is possible to take a short-cut for tuning
1607 graphical objects. For objects that are created directly from
1608 an item in the input file, you can use the @code{\tweak} command.
1611 @lilypond[relative=2,verbatim]
1616 \tweak #'duration-log #1
1619 -\tweak #'padding #8
1623 @cindex chord, modifying one note in
1625 But the main use of the @code{\tweak} command is to modify just
1626 one of a number of notation elements which start at the same musical
1627 moment, like the notes of a chord, or tuplet brackets which start
1630 For an introduction to the syntax and uses of the tweak command
1631 see @rlearning{Tweaking methods}.
1633 The @code{\tweak} command sets a property in the following object
1634 directly, without requiring the grob name or context to be
1635 specified. For this to work, it is necessary for the @code{\tweak}
1636 command to remain immediately adjacent to the object to which it is
1637 to apply after the input file has been converted to a music stream.
1638 This is often not the case, as many additional elements are inserted
1639 into the music stream implicitly. For example, when a note which is
1640 not part of a chord is processed, LilyPond implicitly inserts a
1641 @code{ChordEvent} event before the note, so separating the tweak
1642 from the note. However, if chord symbols are placed round the
1643 tweak and the note, the @code{\tweak} command comes after the
1644 @code{ChordEvent} in the music stream, so remaining adjacent to the
1645 note, and able to modify it.
1649 @lilypond[relative=2,verbatim,quote]
1650 <\tweak #'color #red c>4
1656 @lilypond[relative=2,verbatim,quote]
1657 \tweak #'color #red c4
1660 When several similar items are placed at the same musical moment,
1661 the @code{\override} command cannot be used to modify just one of
1662 them -- this is where the @code{\tweak} command must be used.
1663 Items which may appear more than once at the same musical moment
1664 include the following:
1666 @c TODO expand to include any further uses of \tweak
1668 @item note heads of notes inside a chord
1669 @item articulation signs on a single note
1670 @item ties between notes in a chord
1671 @item tuplet brackets starting at the same time
1674 @c TODO add examples of these
1677 and @code{\tweak} may be used to modify any single occurrence of
1680 Notably the @code{\tweak} command cannot be used to modify stems,
1681 beams or accidentals directly, since these are generated later by
1682 note heads, rather than by music elements in the input stream.
1683 Nor can a @code{\tweak} command be used to modify clefs or time
1684 signatures, since these become separated from any preceding
1685 @code{\tweak} command in the input stream by the automatic
1686 insertion of extra elements required to specify the context.
1688 But the @code{\tweak} command can be used as an alternative to
1689 the @code{\override} command to modify those notational elements
1690 that do not cause any additional implicit elements to be added
1691 before them in the music stream. For example, slurs may be
1692 modified in this way:
1694 @lilypond[verbatim,quote,relative=1]
1695 c-\tweak #'thickness #5 ( d e f)
1698 Also several @code{\tweak} commands may be placed before a
1699 notational element -- all affect it:
1701 @lilypond[verbatim,quote,relative=1]
1703 -\tweak #'style #'dashed-line
1704 -\tweak #'dash-fraction #0.2
1705 -\tweak #'thickness #3
1706 -\tweak #'color #red
1711 The music stream which is generated from a section of an input file,
1712 including any automatically inserted elements, may be examined,
1713 see @ref{Displaying music expressions}. This may be helpful in
1714 determining what may be modified by a @code{\tweak} command.
1719 @rlearning{Tweaking methods}.
1722 @ref{Displaying music expressions}.
1727 @cindex tweaks in a variable
1728 The @code{\tweak} command cannot be used inside a variable.
1730 @cindex tweaks in lyrics
1731 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1733 @cindex tweaking control points
1734 @cindex control points, tweaking
1736 The @code{\tweak} command cannot be used to modify the control
1737 points of just one of several ties in a chord, other than the first
1738 one encountered in the input file.
1740 @node set versus override
1741 @subsection @code{\set} vs. @code{\override}
1743 We have seen two methods of changing properties: @code{\set} and
1744 @code{\override}. There are actually two different kinds of
1747 Contexts can have properties, which are usually named in
1748 @code{studlyCaps}. They mostly control the translation from
1749 music to notation, eg. @code{localKeySignature} (for determining
1750 whether to print accidentals), @code{measurePosition} (for
1751 determining when to print a bar line). Context properties can
1752 change value over time while interpreting a piece of music;
1753 @code{measurePosition} is an obvious example of
1754 this. Context properties are modified with @code{\set}.
1756 There is a special type of context property: the element
1757 description. These properties are named in @code{StudlyCaps}
1758 (starting with capital letters). They contain the
1759 @q{default settings} for said graphical object as an
1760 association list. See @file{scm/@/define@/-grobs@/.scm}
1761 to see what kind of settings there are. Element descriptions
1762 may be modified with @code{\override}.
1764 @code{\override} is actually a shorthand;
1767 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1771 is more or less equivalent to
1773 @c leave this long line -gp
1775 \set @var{context}.@var{name} #'@var{property} = #(cons (cons '@var{property} @var{value}) <previous value of @var{context})
1778 The value of @code{context} (the alist) is used to initialize
1779 the properties of individual grobs. Grobs also have
1780 properties, named in Scheme style, with
1781 @code{dashed-words}. The values of grob properties change
1782 during the formatting process: formatting basically amounts
1783 to computing properties using callback functions.
1785 @code{fontSize} is a special property: it is equivalent to
1786 entering @code{\override ... #'font-size} for all pertinent
1787 objects. Since this is a common change, the special
1788 property (modified with @code{\set}) was created.
1791 @node Useful concepts and properties
1792 @section Useful concepts and properties
1797 * Direction and placement::
1798 * Context layout order::
1799 * Distances and measurements::
1800 * Staff symbol properties::
1802 * Visibility of objects::
1804 * Rotating objects::
1808 @subsection Input modes
1810 The way in which the notation contained within an input file is
1811 interpreted is determined by the current input mode.
1815 This is activated with the @code{\chordmode} command, and causes
1816 input to be interpreted with the syntax of chord notation, see
1817 @ref{Chord notation}. Chords are rendered as notes on a staff.
1819 Chord mode is also activated with the @code{\chords} command.
1820 This also creates a new @code{ChordNames} context and
1821 causes the following input to be interpreted with the syntax of
1822 chord notation and rendered as chord names in the @code{ChordNames}
1823 context, see @ref{Printing chord names}.
1827 This is activated with the @code{\drummode} command, and causes
1828 input to be interpreted with the syntax of drum notation, see
1829 @ref{Basic percussion notation}.
1831 Drum mode is also activated with the @code{\drums} command.
1832 This also creates a new @code{DrumStaff} context and causes the
1833 following input to be interpreted with the syntax of drum notation
1834 and rendered as drum symbols on a drum staff, see @ref{Basic
1835 percussion notation}.
1837 @strong{Figure mode}
1839 This is activated with the @code{\figuremode} command, and causes
1840 input to be interpreted with the syntax of figured bass, see
1841 @ref{Entering figured bass}.
1843 Figure mode is also activated with the @code{\figures} command.
1844 This also creates a new @code{FiguredBass} context and causes the
1845 following input to be interpreted with the figured bass syntax
1846 and rendered as figured bass symbols in the @code{FiguredBass}
1847 context, see @ref{Introduction to figured bass}.
1849 @strong{Fret and tab modes}
1851 There are no special input modes for entering fret and tab symbols.
1853 To create tab diagrams, enter notes or chords in note mode and
1854 render them in a @code{TabStaff} context, see
1855 @ref{Default tablatures}.
1857 To create fret diagrams above a staff, you have two choices.
1858 You can either use the @code{FretBoards} context (see
1859 @ref{Automatic fret diagrams} or you can enter them as a markup
1860 above the notes using the @code{\fret-diagram} command (see
1861 @ref{Fret diagram markups}).
1863 @strong{Lyrics mode}
1865 This is activated with the @code{\lyricmode} command, and causes
1866 input to be interpreted as lyric syllables with optional durations
1867 and associated lyric modifiers, see @ref{Vocal music}.
1869 Lyric mode is also activated with the @code{\addlyrics} command.
1870 This also creates a new @code{Lyrics} context and an implicit
1871 @code{\lyricsto} command which associates the following lyrics
1872 with the preceding music.
1874 @strong{Markup mode}
1876 This is activated with the @code{\markup} command, and causes
1877 input to be interpreted with the syntax of markup, see
1878 @ref{Text markup commands}.
1880 @c silly work-around for texinfo broken-ness
1881 @c (@strong{Note...} causes a spurious cross-reference in Info)
1884 This is the default mode or it may be activated with the
1885 @code{\notemode} command. Input is interpreted as pitches,
1886 durations, markup, etc and typeset as musical notation on a staff.
1888 It is not normally necessary to specify note mode explicitly, but
1889 it may be useful to do so in certain situations, for example if you
1890 are in lyric mode, chord mode or any other mode and want to insert
1891 something that only can be done with note mode syntax.
1893 For example, to indicate dynamic markings for the verses of a
1894 choral pieces it is necessary to enter note mode to interpret
1897 @lilypond[verbatim,relative=2,quote]
1900 \notemode{\set stanza = \markup{ \dynamic f 1. } }
1904 \notemode{\set stanza = \markup{ \dynamic p 2. } }
1911 @node Direction and placement
1912 @subsection Direction and placement
1914 In typesetting music the direction and placement of many items is
1915 a matter of choice. For example, the stems of notes can
1916 be directed up or down; lyrics, dynamics, and other expressive
1917 marks may be placed above or below the staff; text may be aligned
1918 left, right or center; etc. Most of these choices may be left to
1919 be determined automatically by LilyPond, but in some cases it may
1920 be desirable to force a particular direction or placement.
1922 @strong{Articulation direction indicators}
1924 By default some directions are always up or always down (e.g.
1925 dynamics or fermata), while other things can alternate between
1926 up or down based on the stem direction (like slurs or accents).
1928 @c TODO Add table showing these
1930 The default action may be overridden by prefixing the articulation
1931 by a @emph{direction indicator}. Three direction indicators are
1932 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
1933 and @code{-} (meaning @qq{use default direction}). The direction
1934 indicator can usually be omitted, in which case @code{-} is assumed,
1935 but a direction indicator is @strong{always} required before
1938 @item @code{\tweak} commands
1939 @item @code{\markup} commands
1940 @item @code{\tag} commands
1941 @item string markups, e.g. -"string"
1942 @item fingering instructions, e.g. @code{-1}
1943 @item articulation shortcuts, e.g. @code{-.}, @code{->}, @code{--}
1946 Direction indicators affect only the next note:
1948 @lilypond[verbatim,quote,relative=2]
1955 @strong{The direction property}
1957 The position or direction of many layout objects is controlled
1958 by the @code{direction} property.
1960 The value of the @code{direction} property may be
1961 set to @code{1}, meaning @qq{up} or @qq{above}, or to @code{-1},
1962 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
1963 @code{DOWN} may be used instead of @code{1} and @code{-1}
1964 respectively. The default direction may be specified by setting
1965 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
1966 in many cases predefined commands
1967 exist to specify the direction. These are all of the form
1970 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
1973 where @code{xxxNeutral} means @qq{use the default direction}.
1974 See @rlearning{Within-staff objects}.
1976 In a few cases, arpeggio being the only common example, the value
1977 of the @code{direction} property specifies whether the object
1978 is to be placed to the right or left of the parent object. In
1979 this case @code{-1} or @code{LEFT} means @qq{to the left} and
1980 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
1981 or @code{CENTER} means @qq{use the default} direction, as before.
1984 These all have side-axis set to #X
1985 AmbitusAccidental - direction has no effect
1987 StanzaNumber - not tried
1988 TrillPitchAccidental - not tried
1989 TrillPitchGroup - not tried
1992 These indications affect all notes until they are cancelled.
1994 @lilypond[verbatim,quote,relative=2]
2004 @node Context layout order
2005 @subsection Context layout order
2007 @cindex contexts, layout order
2009 Contexts are normally positioned in a system from top to bottom
2010 in the order in which they are encountered in the input file. When
2011 contexts are nested, the outer context will include inner nested
2012 contexts as specified in the input file, provided the inner contexts
2013 are included in the outer context's @qq{accepts} list. Nested
2014 contexts which are not included in the outer context's @qq{accepts}
2015 list will be repositioned below the outer context rather than nested
2018 Note that a context will be silently created implicitly if a command
2019 is encountered when there is no suitable context available to
2020 contain it. This can give rise to unexpected new staves or scores.
2022 The default order in which contexts are laid out and the
2023 @qq{accepts} list can be changed, see @ref{Aligning contexts}.
2027 @rlearning{An extra staff appears}.
2029 @node Distances and measurements
2030 @subsection Distances and measurements
2032 @cindex distances, absolute
2033 @cindex distances, scaled
2040 Distances in LilyPond are of two types: absolute and scaled.
2042 Absolute distances are used for specifying margins, indents, and
2043 other page layout details, and are by default specified in
2044 millimeters. Distances may be specified in other units by
2045 following the quantity by @code{\mm}, @code{\cm},
2046 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27
2047 of an inch). Page layout distances can also be specified in
2048 scalable units (see the following paragraph) by appending
2049 @code{\staff-space} to the quantity.
2050 Page layout is described in detail in @ref{Page formatting}.
2052 Scaled distances are always specified in units of the staff-space
2053 or, rarely, the half staff-space. The staff-space is the distance
2054 between two adjacent staff lines. The default value can be changed
2055 globally by setting the global staff size, or it can be overridden
2056 locally by changing the @code{staff-space} property of
2057 @code{StaffSymbol}. Scaled distances automatically scale with any
2058 change to the either the global staff size or the
2059 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2060 automatically only with changes to the global staff size.
2061 The global staff size thus enables the overall size of a rendered
2062 score to be easily varied. For the methods of setting the global
2063 staff size see @ref{Setting the staff size}.
2067 If just a section of a score needs to be rendered to a different
2068 scale, for example an ossia section or a footnote, the global staff
2069 size cannot simply be changed as this would affect the entire score.
2070 In such cases the change in size is made by overriding both the
2071 @code{staff-space} property of @code{StaffSymbol} and the size of
2072 the fonts. A Scheme function, @code{magstep}, is available to
2073 convert from a font size change to the equivalent change in
2074 @code{staff-space}. For an explanation and an example of its use,
2075 see @rlearning{Length and thickness of objects}.
2080 @rlearning{Length and thickness of objects}.
2083 @ref{Page formatting},
2084 @ref{Setting the staff size}.
2087 @node Staff symbol properties
2088 @subsection Staff symbol properties
2090 @cindex adjusting staff symbol
2091 @cindex drawing staff symbol
2092 @cindex staff symbol, setting of
2094 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2095 @c Need to think of uses for these properties. Eg 'line-positions
2096 @c is used in a snippet to thicken centre line.
2097 @c If retained, add @ref to here in 1.6.2 -td
2099 The vertical position of staff lines and the number of staff lines
2100 can be defined at the same time. As the following example shows,
2101 note positions are not influenced by the staff line positions.
2103 @warning{The @code{'line-positions} property overrides the
2104 @code{'line-count} property. The number of staff lines is
2105 implicitly defined by the number of elements in the list of values
2106 for @code{'line-positions}.}
2108 @lilypond[verbatim,quote,relative=1]
2110 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
2115 The width of a staff can be modified. The units are staff
2116 spaces. The spacing of objects inside the staff is not affected by
2119 @lilypond[verbatim,quote,relative=1]
2121 \override StaffSymbol #'width = #23
2128 @subsection Spanners
2130 Many objects of musical notation extend over several notes or even
2131 several bars. Examples are slurs, beams, tuplet brackets, volta
2132 repeat brackets, crescendi, trills, and glissandi. Such objects
2133 are collectively called @qq{spanners}, and have special properties to control
2134 their appearance and behaviour. Some of these properties are common
2135 to all spanners; others are restricted to a sub-set of the spanners.
2137 All spanners support the @code{spanner-interface}. A few, esentially
2138 those that draw a straight line between the two objects, support in
2139 addition the @code{line-spanner-interface}.
2141 @unnumberedsubsubsec Using the @code{spanner-interface}
2143 This interface provides two properties that apply to several spanners.
2145 @strong{@i{The @code{minimum-length} property}}
2147 The minimum length of the spanner is specified by the
2148 @code{minimum-length} property. Increasing this usually has the
2149 necessary effect of increasing the spacing of the notes between the
2150 two end points. However, this override has no effect on
2151 many spanners, as their length is determined by other considerations.
2152 A few examples where it is effective are shown below.
2162 Works as long as callback is made:
2166 Works not at all for:
2175 @lilypond[verbatim,quote,relative=2]
2178 % increase the length of the tie
2179 -\tweak #'minimum-length #5
2183 @lilypond[verbatim,quote,relative=2]
2185 \compressFullBarRests
2187 % increase the length of the rest bar
2188 \once \override MultiMeasureRest #'minimum-length = #20
2193 @lilypond[verbatim,quote,relative=2]
2195 % increase the length of the hairpin
2196 \override Hairpin #'minimum-length = #20
2200 This override can also be used to increase the length of slurs and
2203 @lilypond[verbatim,quote,relative=2]
2206 -\tweak #'minimum-length #5
2211 -\tweak #'minimum-length #5
2215 For some layout objects, the @code{minimum-length} property becomes
2216 effective only if the @code{set-spacing-rods} procedure is called
2217 explicitly. To do this, the @code{springs-and-rods} property should
2218 be set to @code{ly:spanner::set-spacing-rods}. For example,
2219 the minimum length of a glissando has no effect unless the
2220 @code{springs-and-rods} property is set:
2222 @lilypond[verbatim,quote,relative=1]
2226 % not effective alone
2227 \once \override Glissando #'minimum-length = #20
2230 % effective only when both overrides are present
2231 \once \override Glissando #'minimum-length = #20
2232 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2236 The same is true of the @code{Beam} object:
2238 @lilypond[verbatim,quote,relative=1]
2239 % not effective alone
2240 \once \override Beam #'minimum-length = #20
2243 % effective only when both overrides are present
2244 \once \override Beam #'minimum-length = #20
2245 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2249 @strong{@i{The @code{to-barline} property}}
2251 The second useful property of the @code{spanner-interface} is
2252 @code{to-barline}. By default this is true, causing hairpins and
2253 other spanners which are terminated on the first note of a measure to
2254 end instead on the immediately preceding bar line. If set to false,
2255 the spanner will extend beyond the bar line and end on the note
2258 @lilypond[verbatim,quote,relative=2]
2259 a \< a a a a \! a a a \break
2260 \override Hairpin #'to-barline = ##f
2261 a \< a a a a \! a a a
2264 This property is not effective for all spanners. For example,
2265 seting it to @code{#t} has no effect on slurs or phrasing slurs
2266 or on other spanners for which terminating on the bar line would
2269 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2271 Objects which support the @code{line-spanner-interface} include
2274 @item @code{DynamicTextSpanner}
2275 @item @code{Glissando}
2276 @item @code{TextSpanner}
2277 @item @code{TrillSpanner}
2278 @item @code{VoiceFollower}
2281 The routine responsible for drawing the stencils for these spanners is
2282 @code{ly:line-interface::print}. This routine determines the
2283 exact location of the two end points and draws a line
2284 between them, in the style requested. The locations of the two
2285 end points of the spanner are computed on-the-fly, but it is
2286 possible to override their Y-coordinates. The
2287 properties which need to be specified are nested
2288 two levels down within the property hierarchy, but the syntax of
2289 the @code{\override} command is quite simple:
2291 @lilypond[relative=2,quote,verbatim]
2293 \once \override Glissando #'(bound-details left Y) = #3
2294 \once \override Glissando #'(bound-details right Y) = #-2
2298 The units for the @code{Y} property are @code{staff-space}s,
2299 with the center line of the staff being the zero point.
2300 For the glissando, this is the value for @code{Y} at the
2301 X-coordinate corresponding to the center point of each note head,
2302 if the line is imagined to be extended to there.
2304 If @code{Y} is not set, the value is computed from the vertical
2305 position of the corresponding attachment point of the spanner.
2307 In case of a line break, the values for the end points are
2308 specified by the @code{left-broken} and @code{right-broken}
2309 sub-lists of @code{bound-details}. For example:
2311 @lilypond[relative=2,ragged-right,verbatim,fragment]
2312 \override Glissando #'breakable = ##t
2313 \override Glissando #'(bound-details right-broken Y) = #-3
2314 c1 \glissando \break
2319 A number of further properties of the @code{left} and
2320 @code{right} sub-lists of the @code{bound-details} property
2321 may be modified in the same way as @code{Y}:
2325 This sets the Y-coordinate of the end point, in @code{staff-space}s
2326 offset from the staff center line. By default, it is the center of
2327 the bound object, so a glissando points to the vertical center of
2330 For horizontal spanners, such as text spanners and trill spanners,
2331 it is hardcoded to 0.
2334 This determines where the line starts and ends in the X-direction,
2335 relative to the bound object. So, a value of @code{-1} (or
2336 @code{LEFT}) makes the line start/end at the left side of the note
2337 head it is attached to.
2340 This is the absolute X-coordinate of the end point. It is usually
2341 computed on the fly, and overriding it has little useful effect.
2344 Line spanners may have symbols at the beginning or end, which is
2345 contained in this sub-property. This is for internal use; it is
2346 recommended that @code{text} be used instead.
2349 This is a markup that is evaluated to yield the stencil. It is used
2350 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2352 @lilypond[quote,ragged-right,fragment,relative=2,verbatim]
2353 \override TextSpanner #'(bound-details left text)
2354 = \markup { \small \bold Slower }
2355 c2\startTextSpan b c a\stopTextSpan
2358 @item stencil-align-dir-y
2359 @item stencil-offset
2360 Without setting one of these, the stencil is simply put at the
2361 end-point, centered on the line, as defined by the @code{X} and
2362 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2363 or @code{stencil-offset} will move the symbol at the edge vertically
2364 relative to the end point of the line:
2366 @lilypond[relative=1,fragment,verbatim]
2367 \override TextSpanner
2368 #'(bound-details left stencil-align-dir-y) = #-2
2369 \override TextSpanner
2370 #'(bound-details right stencil-align-dir-y) = #UP
2372 \override TextSpanner
2373 #'(bound-details left text) = #"ggg"
2374 \override TextSpanner
2375 #'(bound-details right text) = #"hhh"
2376 c4^\startTextSpan c c c \stopTextSpan
2379 Note that negative values move the text @emph{up}, contrary to the
2380 effect that might be expected, as a value of @code{-1} or
2381 @code{DOWN} means align the @emph{bottom} edge of the text with
2382 the spanner line. A value of @code{1} or @code{UP} aligns
2383 the top edge of the text with the spanner line.
2386 Setting this sub-property to @code{#t} produces an arrowhead at the
2390 This sub-property controls the space between the specified
2391 end point of the line and the actual end. Without padding, a
2392 glissando would start and end in the center of each note head.
2396 The music function @code{\endSpanners} terminates the spanner
2397 which starts on the immediately following note prematurely. It
2398 is terminated after exactly one note, or at the following bar line
2399 if @code{to-barline} is true and a bar line occurs before the next
2402 @lilypond[verbatim,quote,ragged-right,relative=2,fragment]
2404 c2 \startTextSpan c2 c2
2409 When using @code{\endSpanners} it is not necessary to close
2410 \startTextSpan with \stopTextSpan, nor is it necessary to close
2411 hairpins with @code{\!}.
2415 Internals Reference: @rinternals{TextSpanner},
2416 @rinternals{Glissando}, @rinternals{VoiceFollower},
2417 @rinternals{TrillSpanner},
2418 @rinternals{line-spanner-interface}.
2421 @node Visibility of objects
2422 @subsection Visibility of objects
2424 @cindex objects, visibility of
2425 @cindex grobs, visibility of
2426 @cindex visibility of objects
2428 There are four main ways in which the visibility of layout objects
2429 can be controlled: their stencil can be removed, they can be made
2430 transparent, they can be colored white, or their
2431 @code{break-visibility} property can be overridden. The first
2432 three apply to all layout objects; the last to just a few -- the
2433 @emph{breakable} objects. The Learning Manual introduces these
2434 four techniques, see @rlearning{Visibility and color of objects}.
2436 There are also a few other techniques which are specific to
2437 certain layout objects. These are covered under Special
2441 * Removing the stencil::
2442 * Making objects transparent::
2443 * Painting objects white::
2444 * Using break-visibility::
2445 * Special considerations::
2449 @node Removing the stencil
2450 @unnumberedsubsubsec Removing the stencil
2452 @cindex stencil, removing
2454 Every layout object has a stencil property. By default this is set
2455 to the specific function which draws that object. If this property
2456 is overridden to @code{#f} no function will be called and the object
2457 will not be drawn. The default action can be recovered with
2460 @lilypond[quote,verbatim,relative=1]
2462 \override Score.BarLine #'stencil = ##f
2464 \revert Score.BarLine #'stencil
2468 @node Making objects transparent
2469 @unnumberedsubsubsec Making objects transparent
2471 @cindex transparent, making objects
2473 Every layout object has a transparent property which by default is
2474 set to @code{#f}. If set to @code{#t} the object still occupies
2475 space but is made invisible.
2477 @lilypond[quote,verbatim,relative=2]
2479 \once \override NoteHead #'transparent = ##t
2483 @node Painting objects white
2484 @unnumberedsubsubsec Painting objects white
2486 @cindex objects, coloring
2487 @cindex coloring objects
2489 @cindex printing order
2490 @cindex overwriting objects
2491 @cindex objects, overwriting
2492 @cindex grobs, overwriting
2494 Every layout object has a color property which by default is set
2495 to @code{black}. If this is overridden to @code{white} the object
2496 will be indistinguishable from the white background. However,
2497 if the object crosses other objects the color of the crossing
2498 points will be determined by the order in which they are drawn,
2499 and this may leave a ghostly image of the white object, as shown
2502 @lilypond[quote,verbatim,relative=2]
2503 \override Staff.Clef #'color = #white
2507 This may be avoided by changing the order of printing the objects.
2508 All layout objects have a @code{layer} property which should be set
2509 to an integer. Objects with the lowest value of @code{layer} are
2510 drawn first, then objects with progressively higher values are drawn,
2511 so objects with higher values overwrite objects with lower values.
2512 By default most objects are assigned a @code{layer} value of
2513 @code{1}, although a few objects, including @code{StaffSymbol} and
2514 @code{BarLine}, are assigned a value of @code{0}. The order of
2515 printing objects with the same value of @code{layer} is indeterminate.
2517 In the example above the white clef, with a default @code{layer}
2518 value of @code{1}, is drawn after the staff lines (default
2519 @code{layer} value @code{0}), so overwriting them. To change this,
2520 the @code{Clef} object must be given in a lower value of
2521 @code{layer}, say @code{-1}, so that it is drawn earlier:
2523 @lilypond[quote,verbatim,relative=2]
2524 \override Staff.Clef #'color = #white
2525 \override Staff.Clef #'layer = #-1
2529 @node Using break-visibility
2530 @unnumberedsubsubsec Using break-visibility
2532 @c TODO Add making other objects breakable
2534 @cindex break-visibility
2536 Most layout objects are printed only once, but some like
2537 bar lines, clefs, time signatures and key signatures, may need
2538 to be printed twice when a line break occurs -- once at the end
2539 of the line and again at the start of the next line. Such
2540 objects are called @emph{breakable}, and have a property, the
2541 @code{break-visibility} property to control their visibility
2542 at the three positions in which they may appear -- at the
2543 start of a line, within a line if they are changed, and at the
2544 end of a line if a change takes place there.
2546 For example, the time signature
2547 by default will be printed at the start of the first line, but
2548 nowhere else unless it changes, when it will be printed at the
2549 point at which the change occurs. If this change occurs at the
2550 end of a line the new time signature will be printed at the start
2551 of the next line and a cautionary time signature will be printed
2552 at the end of the previous line as well.
2554 This behaviour is controlled by the @code{break-visibility}
2555 property, which is explained in
2556 @c Leave this ref on a newline - formats incorrectly otherwise -td
2557 @rlearning{Visibility and color of objects}. This property takes
2558 a vector of three booleans which, in order, determine whether the
2559 object is printed at the end of, within the body of, or at the
2560 beginning of a line. Or to be more precise, before a line break,
2561 where there is no line break, or after a line break.
2563 Alternatively, these eight combinations may be specified
2564 by pre-defined functions, defined in @file{scm/output-lib.scm},
2565 where the last three columns indicate whether the layout objects
2566 will be visible in the positions shown at the head of the columns:
2568 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2569 @headitem Function @tab Vector @tab Before @tab At no @tab After
2570 @headitem form @tab form @tab break @tab break @tab break
2572 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2573 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2574 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2575 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2576 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2577 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2578 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2579 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2582 The default settings of @code{break-visibility} depend on the
2583 layout object. The following table shows all the layout objects
2584 of interest which are affected by @code{break-visibility} and the
2585 default setting of this property:
2587 @multitable @columnfractions .3 .3 .4
2589 @headitem Layout object @tab Usual context @tab Default setting
2591 @c omit Ambitus as it appears not to be affected by break-visibility -td
2592 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2593 @item @code{BarLine} @tab @code{Score} @tab calculated
2594 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2595 @c omit the following item until it can be explained -td
2596 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2597 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2598 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2599 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2600 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2601 @c omit KeyCancellation until it can be explained -td
2602 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2603 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2604 @c omit LeftEdge until it can be explained -td
2605 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2606 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2607 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2608 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2612 The example below shows the use of the vector form to control the
2613 visibility of barlines:
2615 @lilypond[quote,verbatim,relative=1,ragged-right]
2618 % Remove bar line at the end of the current line
2619 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2625 Although all three components of the vector used to override
2626 @code{break-visibility} must be present, not all of them are
2627 effective with every layout object, and some combinations may
2628 even give errors. The following limitations apply:
2631 @item Bar lines cannot be printed at start of line.
2632 @item A bar number cannot be printed at the start of the first
2633 line unless it is set to be different from 1.
2634 @item Clef -- see below
2635 @item Double percent repeats are either all printed or all
2636 suppressed. Use begin-of line-invisible to print and
2637 all-invisible to suppress.
2638 @item Key signature -- see below
2639 @item OctavateEight -- see below
2642 @node Special considerations
2643 @unnumberedsubsubsec Special considerations
2645 @strong{@emph{Visibility following explicit changes}}
2647 @cindex key signature, visibility following explicit change
2648 @cindex explicitKeySignatureVisibility
2649 @cindex clef, visibility following explicit change
2650 @cindex explicitClefVisibility
2652 The @code{break-visibility} property controls the visibility of
2653 key signatures and changes of clef only at the start of lines,
2654 i.e. after a break. It has no effect on the visibility of the
2655 key signature or clef following an explicit key change or an
2656 explicit clef change within or at the end of a line. In the
2657 following example the key signature following the explicit change
2658 to B-flat major is still visible, even though @code{all-invisible}
2661 @lilypond[quote,verbatim,relative=1,ragged-right]
2664 % Try to remove all key signatures
2665 \override Staff.KeySignature #'break-visibility = #all-invisible
2673 The visibility of such explicit key signature and clef changes is
2674 controlled by the @code{explicitKeySignatureVisibility} and
2675 @code{explicitClefVisibility} properties. These are the equivalent
2676 of the @code{break-visibility} property and both take a vector of
2677 three booleans or the predefined functions listed above, exactly like
2678 @code{break-visibility}. Both are properties of the Staff context,
2679 not the layout objects themselves, and so they are set using the
2680 @code{\set} command. Both are set by default to @code{all-visible}.
2681 These properties control only the visibility of key signatures and
2682 clefs resulting from explicit changes and do not affect key
2683 signatures and clefs at the beginning of lines;
2684 @code{break-visibility} must still be overridden in the appropriate
2685 object to remove these.
2687 @lilypond[quote,verbatim,relative=1,ragged-right]
2690 \set Staff.explicitKeySignatureVisibility = #all-invisible
2691 \override Staff.KeySignature #'break-visibility = #all-invisible
2698 @strong{@emph{Visibility of cautionary accidentals}}
2700 To remove the cautionary accidentals printed at an explicit key
2701 change, set the Staff context property @code{printKeyCancellation}
2704 @lilypond[quote,verbatim,relative=1,ragged-right]
2707 \set Staff.explicitKeySignatureVisibility = #all-invisible
2708 \set Staff.printKeyCancellation = ##f
2709 \override Staff.KeySignature #'break-visibility = #all-invisible
2716 With these overrides only the accidentals before the notes remain
2717 to indicate the change of key.
2719 @c TODO Add visibility of cautionary accidentals before notes
2721 @strong{@emph{Automatic bars}}
2723 @cindex automaticBars
2724 @cindex bar lines, suppressing
2726 As a special case, the printing of bar lines can also be turned off
2727 by setting the @code{automaticBars} property in the Score context.
2728 If set to @code{#f}, bar lines will not be printed automatically;
2729 they must be explicitly created with a @code{\bar} command. Unlike
2730 the @code{\cadenzaOn} predefined command, measures are still counted.
2731 Bar generation will resume according to that count if this property
2732 is later set to @code{#t}. When set to @code{#f}, line breaks can
2733 occur only at explicit @code{\bar} commands.
2737 @strong{@emph{Octavated clefs}}
2739 @cindex octavated clefs, visibility of
2740 @cindex visibility of octavated clefs
2741 @cindex clefs, visibility of octavation
2743 The small octavation symbol on octavated clefs is produced by the
2744 @code{OctavateEight} layout object. Its visibility is controlled
2745 independently from that of the @code{Clef} object, so it is
2746 necessary to apply any required @code{break-visibility} overrides
2747 to both the @code{Clef} and the @code{OctavateEight} layout objects
2748 to fully suppress such clef symbols at the start of each line.
2750 For explicit clef changes, the @code{explicitClefVisibility}
2751 property controls both the clef symbol and any octavation symbol
2757 @rlearning{Visibility and color of objects}
2761 @subsection Line styles
2763 Some performance indications, e.g., @i{rallentando} and
2764 @i{accelerando} and @i{trills} are written as text and are
2765 extended over many measures with lines, sometimes dotted or wavy.
2767 These all use the same routines as the glissando for drawing the
2768 texts and the lines, and tuning their behavior is therefore also
2769 done in the same way. It is done with a spanner, and the routine
2770 responsible for drawing the spanners is
2771 @code{ly:line-interface::print}. This routine determines the
2772 exact location of the two @i{span points} and draws a line
2773 between them, in the style requested.
2775 Here is an example showing the different line styles available,
2776 and how to tune them.
2778 @lilypond[relative=2,ragged-right,verbatim,fragment]
2780 \once \override Glissando #'style = #'dashed-line
2782 \override Glissando #'style = #'dotted-line
2784 \override Glissando #'style = #'zigzag
2786 \override Glissando #'style = #'trill
2790 The locations of the end-points of the spanner are computed
2791 on-the-fly for every graphic object, but it is possible to
2795 @lilypond[relative=2,ragged-right,verbatim,fragment]
2797 \once \override Glissando #'(bound-details right Y) = #-2
2801 The value for @code{Y} is set to @code{-2} for the right end
2802 point. The left side may be similarly adjusted by specifying
2803 @code{left} instead of @code{right}.
2805 If @code{Y} is not set, the value is computed from the vertical
2806 position of the left and right attachment points of the spanner.
2808 Other adjustments of spanners are possible, for details, see
2811 @node Rotating objects
2812 @subsection Rotating objects
2814 Both layout objects and elements of markup text can be rotated by
2815 any angle about any point, but the method of doing so differs.
2818 * Rotating layout objects::
2822 @node Rotating layout objects
2823 @unnumberedsubsubsec Rotating layout objects
2825 @cindex rotating objects
2826 @cindex objects, rotating
2828 All layout objects which support the @code{grob-interface} can be
2829 rotated by setting their @code{rotation} property. This takes a
2830 list of three items: the angle of rotation counter-clockwise,
2831 and the x and y coordinates of the point relative to the object's
2832 reference point about which the rotation is to be performed. The
2833 angle of rotation is specified in degrees and the coordinates in
2836 The angle of rotation and the coordinates of the rotation point must
2837 be determined by trial and error.
2839 @cindex hairpins, angled
2840 @cindex angled hairpins
2842 There are only a few situations where the rotation of layout
2843 objects is useful; the following example shows one situation where
2846 @lilypond[quote,verbatim,relative=1]
2848 \override Hairpin #'rotation = #'(20 -1 0)
2852 @node Rotating markup
2853 @unnumberedsubsubsec Rotating markup
2855 All markup text can be rotated to lie at any angle by prefixing it
2856 with the @code{\rotate} command. The command takes two arguments:
2857 the angle of rotation in degrees counter-clockwise and the text to
2858 be rotated. The extents of the text are not rotated: they take
2859 their values from the extremes of the x and y coordinates of the
2860 rotated text. In the following example the
2861 @code{outside-staff-priority} property for text is set to @code{#f}
2862 to disable the automatic collision avoidance, which would push some
2863 of the text too high.
2865 @lilypond[quote,verbatim,relative=1]
2866 \override TextScript #'outside-staff-priority = ##f
2867 g4^\markup { \rotate #30 "a G" }
2868 b^\markup { \rotate #30 "a B" }
2869 des^\markup { \rotate #30 "a D-Flat" }
2870 fis^\markup { \rotate #30 "an F-Sharp" }
2873 @node Advanced tweaks
2874 @section Advanced tweaks
2876 This section discusses various approaches to fine tuning the
2877 appearance of the printed score.
2880 * Aligning objects::
2881 * Vertical grouping of grobs::
2882 * Modifying stencils::
2883 * Modifying shapes::
2889 @rlearning{Tweaking output},
2890 @rlearning{Other sources of information}.
2893 @ref{Explaining the Internals Reference},
2894 @ref{Modifying properties},
2895 @ref{Interfaces for programmers}.
2898 @file{scm/@/define@/-grobs@/.scm}.
2901 @rlsr{Tweaks and overrides}.
2903 Internals Reference:
2904 @rinternals{All layout objects}.
2907 @node Aligning objects
2908 @subsection Aligning objects
2910 Graphical objects which support the @code{self-alignment-interface} and/or
2911 the @code{side-position-interface} can be
2912 aligned to a previously placed object in a variety of ways. For a list of these objects, see
2913 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
2915 All graphical objects have a reference point, a horizontal extent and a
2916 vertical extent. The horizontal extent is a pair of numbers
2917 giving the displacements from the reference point of the left and
2918 right edges, displacements to the left being negative. The
2919 vertical extent is a pair of numbers giving the displacement from
2920 the reference point to the bottom and top edges, displacements down
2923 An object's position on a staff is given by the values of the
2924 @code{X-offset} and @code{Y-offset} properties. The value of
2925 @code{X-offset} gives the displacement from the x coordinate of
2926 the reference point of the parent object, and the value of
2927 @code{Y-offset} gives the displacement from the center line of the
2928 staff. The values of @code{X-offset} and
2929 @code{Y-offset} may be set directly or may be set to be calculated
2930 by procedures in order to achieve alignment with the parent object
2933 @warning{Many objects have special positioning considerations which
2934 cause any setting of @code{X-offset} or @code{Y-offset} to be
2935 ignored or modified, even though the object supports the
2936 @code{self-alignment-interface}.}
2938 For example, an accidental can be repositioned
2939 vertically by setting @code{Y-offset} but any changes to
2940 @code{X-offset} have no effect.
2942 Rehearsal marks may be aligned with
2943 breakable objects such as bar lines, clef symbols, time signature
2944 symbols and key signatures. There are special properties to be
2945 found in the @code{break-aligned-interface} for positioning rehearsal
2946 marks on such objects.
2949 * Setting @code{X-offset} and @code{Y-offset} directly::
2950 * Using the @code{side-position-interface}::
2951 * Using the @code{self-alignment-interface}::
2952 * Using the @code{break-alignable-interface}::
2955 @node Setting @code{X-offset} and @code{Y-offset} directly
2956 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
2958 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
2959 properties of many objects. The following example shows three
2960 notes with the default fingering position and the positions with @code{X-offset}
2961 and @code{Y-offset} modified.
2963 @lilypond[verbatim,quote,relative=2]
2966 -\tweak #'X-offset #0
2967 -\tweak #'Y-offset #0
2970 -\tweak #'X-offset #-1
2971 -\tweak #'Y-offset #1
2977 @node Using the @code{side-position-interface}
2978 @unnumberedsubsubsec Using the @code{side-position-interface}
2980 An object which supports the @code{side-position-interface} can be
2981 placed next to its parent object so that
2982 the specified edges of the two objects touch. The object may be
2983 placed above, below, to the right or to the left of the parent.
2984 The parent cannot be specified; it is determined by the order of
2985 elements in the input stream. Most objects have the associated
2986 note head as their parent.
2988 The values of the @code{side-axis} and @code{direction} properties
2989 determine where the object is to be placed, as follows:
2991 @c TODO add an example of each to the table
2993 @multitable @columnfractions .3 .3 .3
2994 @headitem @code{side-axis} @tab @code{direction} @tab
2995 @headitem property @tab property @tab Placement
2997 @item @code{0} @tab @code{-1} @tab left
2998 @item @code{0} @tab @code{1} @tab right
2999 @item @code{1} @tab @code{-1} @tab below
3000 @item @code{1} @tab @code{1} @tab above
3004 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
3005 the procedure @code{ly:side-position-interface::x-aligned-side}.
3006 This procedure will return the correct value of @code{X-offset} to
3007 place the object to the left or right side of the parent according
3008 to value of @code{direction}.
3010 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3011 the procedure @code{ly:side-position-interface::y-aligned-side}.
3012 This procedure will return the correct value of @code{Y-offset} to
3013 place the object to the top or bottom of the parent according
3014 to value of @code{direction}.
3016 @c TODO Add examples
3018 @node Using the @code{self-alignment-interface}
3019 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3021 @emph{Self-aligning objects horizontally}
3023 The horizontal alignment of an object which supports the
3024 @code{self-alignment-interface} is controlled by the value of
3025 the @code{self-alignment-X} property, provided the object's
3026 @code{X-offset} property is set to
3027 @code{ly:self-alignment-interface::x-aligned-on-self}.
3028 @code{self-alignment-X} may be given any
3029 real value, in units of half the total X extent of the
3030 object. Negative values move the object to the right, positive
3031 to the left. A value of @code{0} centers the object on the
3032 reference point of its parent, a value of @code{-1} aligns the
3033 left edge of the object on the reference point of its parent,
3034 and a value of @code{1} aligns the right edge of the object on the
3035 reference point of its parent. The symbols @code{LEFT},
3036 @code{CENTER} and @code{RIGHT} may be used instead of the values
3037 @code{-1, 0, 1} respectively.
3039 Normally the @code{\override} command would be used to modify the
3040 value of @code{self-alignment-X}, but the @code{\tweak} command
3041 can be used to separately align several annotations on a single
3044 @lilypond[quote,verbatim,relative=1]
3046 -\tweak #'self-alignment-X #-1
3048 -\tweak #'self-alignment-X #0
3050 -\tweak #'self-alignment-X #RIGHT
3052 -\tweak #'self-alignment-X #-2.5
3053 ^"aligned further to the right"
3056 @emph{Self-aligning objects vertically}
3058 Objects may be aligned vertically in an analogous way to aligning
3059 them horizontally if the @code{Y-offset} property is set to
3060 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3061 other mechanisms are often involved in vertical alignment: the
3062 value of @code{Y-offset} is just one variable taken into account.
3063 This may make adjusting the value of some objects tricky.
3064 The units are just half the vertical extent of the object, which
3065 is usually quite small, so quite large numbers may be required.
3066 A value of @code{-1} aligns the lower edge of the object with
3067 the reference point of the parent object, a value of @code{0}
3068 aligns the center of the object with the reference point of the
3069 parent, and a value of @code{1} aligns the top edge of the object
3070 with the reference point of the parent. The symbols @code{DOWN},
3071 @code{CENTER}, @code{UP} may be substituted for @code{-1, 0, 1}
3074 @emph{Self-aligning objects in both directions}
3076 By setting both @code{X-offset} and @code{Y-offset}, an object may
3077 be aligned in both directions simultaneously.
3079 The following example shows how to adjust a fingering mark so
3080 that it nestles close to the note head.
3082 @lilypond[quote,verbatim,relative=2]
3084 -\tweak #'self-alignment-X #0.5 % move horizontally left
3085 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
3086 -\tweak #'self-alignment-Y #-1 % move vertically up
3091 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3093 @c Cannot document as they do not seem to operate consistently on all objects -td
3094 @c TODO investigate further
3096 The @code{aligned-on-parent} procedures are used in the same way
3097 as the @code{aligned-on-self} procedures, they difference being
3098 that they permit an object to be aligned with the @emph{edges} of
3099 the parent rather than the parent's reference point. The following
3100 example shows the difference:
3104 @lilypond[verbatim,quote]
3110 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3112 @c Cannot document as they do not seem to operate consistently on all objects -td
3113 @c TODO investigate further
3117 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3119 @node Using the @code{break-alignable-interface}
3120 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3122 @cindex align to objects
3123 @cindex break-align-symbols
3125 Rehearsal marks and bar numbers may be aligned with notation
3126 objects other than bar lines. These objects include @code{ambitus},
3127 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3128 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3129 @code{time-signature}.
3131 By default, rehearsal marks and bar numbers will be horizontally
3132 centered above the object:
3134 @lilypond[verbatim,quote,relative=1]
3136 % the RehearsalMark will be centered above the Clef
3137 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
3142 % the RehearsalMark will be centered above the TimeSignature
3143 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
3151 A list of possible target alignment objects may be specified. If
3152 some of the objects are invisible at that point due to the setting
3153 of @code{break-visibility} or the explicit visibility settings for
3154 keys and clefs, the rehearsal mark or bar number is aligned to the
3155 first object in the list which is visible. If no objects in the
3156 list are visible the object is aligned to the bar line. If the bar
3157 line is invisible the object is aligned to the place where the bar
3160 @lilypond[verbatim,quote,relative=1]
3162 % the RehearsalMark will be centered above the Key Signature
3163 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3168 % the RehearsalMark will be centered above the Clef
3169 \set Staff.explicitKeySignatureVisibility = #all-invisible
3170 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3177 The alignment of the rehearsal mark relative to the notation object
3178 can be changed, as shown in the following example. In a score with
3179 multiple staves, this setting should be done for all the staves.
3181 @lilypond[verbatim,quote,relative=1]
3182 % The RehearsalMark will be centered above the KeySignature
3183 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3189 % The RehearsalMark will be aligned with the left edge of the KeySignature
3190 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3194 % The RehearsalMark will be aligned with the right edge of the KeySignature
3195 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3201 The rehearsal mark can also be offset to the right or left of the left edge
3202 by an arbitrary amount. The units are staff-spaces:
3204 @lilypond[verbatim,quote,relative=1]
3205 % The RehearsalMark will be aligned with the left edge of the KeySignature
3206 % and then shifted right by 3.5 staff-spaces
3207 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3208 \once \override Score.KeySignature #'break-align-anchor = #3.5
3212 % The RehearsalMark will be aligned with the left edge of the KeySignature
3213 % and then shifted left by 2 staff-spaces
3214 \once \override Score.KeySignature #'break-align-anchor = #-2
3221 @node Vertical grouping of grobs
3222 @subsection Vertical grouping of grobs
3224 @c FIXME Expand this section
3226 The VerticalAlignment and VerticalAxisGroup grobs work together.
3227 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3228 etc. VerticalAlignment then vertically aligns the different grobs
3229 grouped together by VerticalAxisGroup. There is usually only one
3230 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3234 @node Modifying stencils
3235 @subsection Modifying stencils
3237 All layout objects have a @code{stencil} property which is part of
3238 the @code{grob-interface}. By default, this property is usually
3239 set to a function specific to the object that is tailor-made to
3240 render the symbol which represents it in the output. For example,
3241 the standard setting for the @code{stencil} property of the
3242 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3244 The standard symbol for any object can be replaced by modifying the
3245 @code{stencil} property to reference a different, specially-written,
3246 procedure. This requires a high level of knowledge of the internal
3247 workings of LilyPond, but there is an easier way which can often
3248 produce adequate results.
3250 This is to set the @code{stencil} property to the procedure which
3251 prints text -- @code{ly:text-interface::print} -- and to add a
3252 @code{text} property to the object which is set to contain the
3253 markup text which produces the required symbol. Due to the
3254 flexibility of markup, much can be achieved -- see in particular
3255 @ref{Graphic notation inside markup}.
3257 The following example demonstrates this by changing the note head
3258 symbol to a cross within a circle.
3260 @lilypond[verbatim,quote]
3262 \once \override NoteHead #'stencil = #ly:text-interface::print
3263 \once \override NoteHead #'text = \markup {
3265 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3266 \musicglyph #"noteheads.s2cross"
3274 Any of the glyphs in the feta Font can be supplied to the
3275 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3277 @c TODO Add inserting eps files or ref to later
3279 @c TODO Add inserting Postscript or ref to later
3284 @ref{Graphic notation inside markup},
3285 @ref{Formatting text},
3286 @ref{Text markup commands},
3287 @ref{The Feta font}.
3290 @node Modifying shapes
3291 @subsection Modifying shapes
3294 * Modifying ties and slurs::
3297 @node Modifying ties and slurs
3298 @unnumberedsubsubsec Modifying ties and slurs
3300 @cindex slurs, modifying
3301 @cindex ties, modifying
3302 @cindex Bézier curves
3303 @cindex Bézier control points
3305 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3306 curves. If the shape of the tie or slur which is calculated
3307 automatically is not optimum, the shape may be modified manually by
3308 explicitly specifying the four control points required to define
3309 a third-order Bézier curve.
3311 Third-order or cubic Bézier curves are defined by four control
3312 points. The first and fourth control points are precisely the
3313 starting and ending points of the curve. The intermediate two
3314 control points define the shape. Animations showing how the curve
3315 is drawn can be found on the web, but the following description
3316 may be helpful. The curve starts from the first control point
3317 heading directly towards the second, gradually bending over to
3318 head towards the third and continuing to bend over to head towards
3319 the fourth, arriving there travelling directly from the third
3320 control point. The curve is entirely contained in the
3321 quadrilateral defined by the four control points.
3323 Here is an example of a case where the tie is not optimum, and
3324 where @code{\tieDown} would not help.
3326 @lilypond[verbatim,quote,relative=1]
3330 { r4 <g c,> <g c,> <g c,> }
3334 One way of improving this tie is to manually modify its control
3337 The coordinates of the Bézier control points are specified in units
3338 of staff-spaces. The X@tie{}coordinate is relative to the reference
3339 point of the note to which the tie or slur is attached, and the
3340 Y@tie{}coordinate is relative to the staff center line. The
3341 coordinates are entered as a list of four pairs of decimal numbers
3342 (reals). One approach is to estimate the coordinates of the two
3343 end points, and then guess the two intermediate points. The optimum
3344 values are then found by trial and error.
3346 It is useful to remember that a symmetric curve requires symmetric
3347 control points, and that Bézier curves have the useful property that
3348 transformations of the curve such as translation, rotation and
3349 scaling can be achieved by applying the same transformation to the
3350 curve's control points.
3352 For the example above the following override gives a satisfactory
3353 tie. Note the placement -- it has to be immediately before the note
3354 to which the start of the tie (or slur) is attached.
3356 @lilypond[verbatim,quote,relative=1]
3360 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3364 { r4 <g c,> <g c,> <g c,>4 }
3370 It is not possible to modify shapes of ties or slurs by changing
3371 the @code{control-points} property if there are more than one at
3372 the same musical moment, not even by using the @code{\tweak}