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{ChordNames}}
238 Typesets chord names.
243 Then the following, which I don't know what to do with:
245 * GregorianTranscriptionVoice
246 * GregorianTranscriptionStaff
249 Engraves fretboards from chords. Not easy... Not
251 There is now some documentation on FretBoards in the NR, under
252 instrument-specific notation -- cds.
256 * CueVoice Not documented
258 Hard coded entry point for LilyPond. Cannot be tuned.
260 Silently discards all musical information given to this
265 @node Creating contexts
266 @subsection Creating contexts
268 @c TODO \new Score and \score
269 @c TODO more complete descriptions rather than learning style
271 For scores with only one voice and one staff, contexts are
272 created automatically. For more complex scores, it is necessary to
273 create them by hand. There are three commands that do this.
278 The easiest command is @code{\new}, and it also the quickest to type.
279 It is prepended to a music expression, for example
283 @cindex Context, creating
286 \new @var{type} @var{music expression}
290 where @var{type} is a context name (like @code{Staff} or
291 @code{Voice}). This command creates a new context, and starts
292 interpreting the @var{music expression} with that.
294 A practical application of @code{\new} is a score with many
295 staves. Each part that should be on its own staff, is preceded with
298 @lilypond[quote,verbatim,relative=2,ragged-right,fragment]
305 The @code{\new} command may also give a name to the context,
308 \new @var{type} = @var{id} @var{music}
310 However, this user specified name is only used if there is no other
311 context already earlier with the same name.
317 Like @code{\new}, the @code{\context} command also directs a music
318 expression to a context object, but gives the context an explicit name. The
322 \context @var{type} = @var{id} @var{music}
325 This form will search for an existing context of type @var{type}
326 called @var{id}. If that context does not exist yet, a new
327 context with the specified name is created. This is useful if
328 the context is referred to later on. For example, when
329 setting lyrics the melody is in a named context
332 \context Voice = "@b{tenor}" @var{music}
336 so the texts can be properly aligned to its notes,
339 \new Lyrics \lyricsto "@b{tenor}" @var{lyrics}
344 Another possible use of named contexts is funneling two different
345 music expressions into one context. In the following example,
346 articulations and notes are entered separately,
350 arts = @{ s4-. s4-> @}
353 They are combined by sending both to the same @code{Voice} context,
357 \new Staff \context Voice = "A" \music
358 \context Voice = "A" \arts
361 @lilypond[quote,ragged-right]
365 \new Staff \context Voice = "A" \music
366 \context Voice = "A" \arts
370 With this mechanism, it is possible to define an Urtext (original
371 edition), with the option to put several distinct articulations on the
374 @cindex creating contexts
377 The third command for creating contexts is
379 \context @var{type} @var{music}
384 This is similar to @code{\context} with @code{= @var{id}}, but matches
385 any context of type @var{type}, regardless of its given name.
387 This variant is used with music expressions that can be interpreted at
388 several levels. For example, the @code{\applyOutput} command (see
389 @ref{Running a function on all layout objects}). Without an explicit
390 @code{\context}, it is usually applied to @code{Voice}
393 \applyOutput #'@var{context} #@var{function} % apply to Voice
396 To have it interpreted at the @code{Score} or @code{Staff} level use
400 \applyOutput #'Score #@var{function}
401 \applyOutput #'Staff #@var{function}
406 @node Keeping contexts alive
407 @subsection Keeping contexts alive
409 @cindex contexts, keeping alive
410 @cindex contexts, lifetime
412 Contexts are usually terminated at the first musical moment in
413 which they have nothing to do. So @code{Voice} contexts die as
414 soon as they contain no events; @code{Staff} contexts die as soon
415 as all the @code{Voice} contexts within them contain no events; etc.
416 This can cause difficulties if earlier contexts which have died
417 have to be referenced, for example, when changing staves with
418 @code{\change} commands, associating lyrics with a voice with
419 @code{\lyricsto} commands, or when adding further musical events to
422 There is an exception to this general rule: just one of the
423 @code{Voice} contexts in a @code{Staff} context or in a
424 @code{<<...>>} construct will always persist to the end of the
425 enclosing @code{Staff} context or @code{<<...>>} construct, even
426 though there may be periods when it has nothing to do. The context
427 to persist in this way will be the first one encountered in the
428 first enclosed @code{@{...@}} construct, ignoring any in enclosed
429 @code{<<...>>} constructs.
431 Any context can be kept alive by ensuring it has something to do at
432 every musical moment. @code{Staff} contexts are kept alive by
433 ensuring one of their voices is kept alive. One way of doing this
434 is to add spacer rests to a voice in parallel with the real music.
435 These need to be added to every @code{Voice} context which needs to
436 be kept alive. If several voices are to be used sporadically it is
437 safest to keep them all alive rather than attempting to rely on the
438 exceptions mentioned above.
440 In the following example, both voice A and voice B are kept alive
441 in this way for the duration of the piece:
443 @lilypond[quote,verbatim]
444 musicA = \relative c'' { d4 d d d }
445 musicB = \relative c'' { g4 g g g }
448 \new Voice = "A" { s1*5 } % Keep Voice "A" alive for 5 bars
449 \new Voice = "B" { s1*5 } % Keep Voice "B" alive for 5 bars
454 \context Voice = "A" {
458 \context Voice = "B" {
462 \context Voice = "A" { \musicA }
463 \context Voice = "B" { \musicB }
464 \context Voice = "A" { \musicA }
475 @cindex lyrics, aligning with sporadic melody
477 The following example shows how a sporadic melody line with lyrics
478 might be written using this approach. In a real situation the
479 melody and accompaniment would consist of several different
482 @lilypond[quote,verbatim]
483 melody = \relative c'' { a4 a a a }
484 accompaniment = \relative c' { d4 d d d }
485 words = \lyricmode { These words fol -- low the mel -- o -- dy }
488 \new Staff = "music" {
490 \new Voice = "melody" {
492 s1*4 % Keep Voice "melody" alive for 4 bars
495 \new Voice = "accompaniment" {
500 \context Voice = "melody" { \melody }
501 \context Voice = "accompaniment" { \accompaniment }
503 \context Voice = "accompaniment" { \accompaniment }
505 \context Voice = "melody" { \melody }
506 \context Voice = "accompaniment" { \accompaniment }
511 \new Lyrics \with { alignAboveContext = #"music" }
512 \lyricsto "melody" { \words }
517 An alternative way, which may be better in many circumstances, is
518 to keep the melody line alive by simply including spacer notes to
519 line it up correctly with the accompaniment:
521 @lilypond[quote,verbatim]
522 melody = \relative c'' {
528 accompaniment = \relative c' {
534 words = \lyricmode { These words fol -- low the mel -- o -- dy }
538 \new Staff = "music" {
540 \new Voice = "melody" {
544 \new Voice = "accompaniment" {
550 \new Lyrics \with { alignAboveContext = #"music" }
551 \lyricsto "melody" { \words }
557 @node Modifying context plug-ins
558 @subsection Modifying context plug-ins
560 @c TODO Should this be Modifying engravers or Modifying contexts?
562 Notation contexts (like @code{Score} and @code{Staff}) not only
564 they also contain plug-ins called @q{engravers} that create notation
565 elements. For example, the @code{Voice} context contains a
566 @code{Note_head_engraver} and the @code{Staff} context contains a
567 @code{Key_signature_engraver}.
569 For a full a description of each plug-in, see
571 @rinternals{Engravers and Performers}.
574 Internals Reference @expansion{} Translation @expansion{} Engravers.
576 Every context described in
578 @rinternals{Contexts}
581 Internals Reference @expansion{} Translation @expansion{} Context.
583 lists the engravers used for that context.
586 It can be useful to shuffle around these plug-ins. This is done by
587 starting a new context with @code{\new} or @code{\context}, and
593 \new @var{context} \with @{
606 where the @dots{} should be the name of an engraver. Here is a simple
607 example which removes @code{Time_signature_engraver} and
608 @code{Clef_engraver} from a @code{Staff} context,
610 @lilypond[quote,relative=1,verbatim,fragment]
616 \remove "Time_signature_engraver"
617 \remove "Clef_engraver"
624 In the second staff there are no time signature or clef symbols. This
625 is a rather crude method of making objects disappear since it will affect
626 the entire staff. This method also influences the spacing, which may or
627 may not be desirable. More sophisticated methods of blanking objects
628 are shown in @rlearning{Visibility and color of objects}.
630 The next example shows a practical application. Bar lines and time
631 signatures are normally synchronized across the score. This is done
632 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
633 This plug-in keeps an administration of time signature, location
634 within the measure, etc. By moving these engraver from @code{Score} to
635 @code{Staff} context, we can have a score where each staff has its own
638 @cindex polymetric scores
639 @cindex Time signatures, multiple
641 @lilypond[quote,relative=1,ragged-right,verbatim,fragment]
643 \remove "Timing_translator"
644 \remove "Default_bar_line_engraver"
647 \consists "Timing_translator"
648 \consists "Default_bar_line_engraver"
654 \consists "Timing_translator"
655 \consists "Default_bar_line_engraver"
665 Usually the order in which the engravers are specified
666 does not matter, but in a few special cases the order
667 is important, for example where one engraver writes
668 a property and another reads it, or where one engraver
669 creates a grob and another must process it. The order in
670 which the engravers are specified is the order in which
671 they are called to carry out their processing.
673 The following orderings are important: the
674 @code{Bar_engraver} must normally be first, and
675 the @code{New_fingering_engraver} must come before
676 the @code{Script_column_engraver}. There may be others
677 with ordering dependencies.
679 @node Changing context default settings
680 @subsection Changing context default settings
682 The context settings which are to be used by default in
683 @code{Score}, @code{Staff} and @code{Voice} contexts may be specified
684 in a @code{\layout} block, as illustrated in the following example.
685 The @code{\layout} block should be placed within the @code{\score}
686 block to which it is to apply, but outside any music.
688 Note that the @code{\set} command itself and the context must be
689 omitted when the context default values are specified in this way:
691 @lilypond[quote,verbatim]
694 a4^"Really small, thicker stems, no time signature" a a a
701 \override Stem #'thickness = #4.0
702 \remove "Time_signature_engraver"
708 In this example, the @code{\Staff} command specifies that the
709 subsequent specifications are to be applied to all staves within
712 Modifications can be made to the @code{Score} context or all
713 @code{Voice} contexts in a similar way.
717 It is not possible to collect context changes in a variable and apply
718 them to a @code{\context} definition by referring to that variable.
720 The @code{\RemoveEmptyStaffContext} will overwrite your current
721 @code{\Staff} settings. If you wish to change the defaults for a
722 staff which uses @code{\RemoveEmptyStaffContext}, you must do so
723 after calling @code{\RemoveEmptyStaffContext}, ie
728 \RemoveEmptyStaffContext
730 \override Stem #'thickness = #4.0
735 @c TODO: add \with in here.
739 @node Defining new contexts
740 @subsection Defining new contexts
742 Specific contexts, like @code{Staff} and @code{Voice}, are made of
743 simple building blocks. It is possible to create new types of
744 contexts with different combinations of engraver plug-ins.
746 The next example shows how to build a different type of
747 @code{Voice} context from scratch. It will be similar to
748 @code{Voice}, but only prints centered slash note heads. It can be used
749 to indicate improvisation in jazz pieces,
751 @lilypond[quote,ragged-right]
754 \type "Engraver_group"
755 \consists "Note_heads_engraver"
756 \consists "Rhythmic_column_engraver"
757 \consists "Text_engraver"
758 \consists Pitch_squash_engraver
759 squashedPosition = #0
760 \override NoteHead #'style = #'slash
761 \override Stem #'transparent = ##t
765 \accepts "ImproVoice"
769 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
770 c4 c^"undress" c_"while playing :)" c }
776 These settings are defined within a @code{\context} block inside a
777 @code{\layout} block,
787 In the following discussion, the example input shown should go in place
788 of the @dots{} in the previous fragment.
790 First it is necessary to define a name for the new context:
796 Since it is similar to the @code{Voice}, we want commands that work
797 on (existing) @code{Voice}s to remain working. This is achieved by
798 giving the new context an alias @code{Voice},
804 The context will print notes and instructive texts, so we need to add
805 the engravers which provide this functionality,
808 \consists Note_heads_engraver
809 \consists Text_engraver
812 but we only need this on the center line,
815 \consists Pitch_squash_engraver
816 squashedPosition = #0
819 The @rinternals{Pitch_squash_engraver} modifies note heads (created
820 by @rinternals{Note_heads_engraver}) and sets their vertical
821 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
824 The notes look like a slash, and have no stem,
827 \override NoteHead #'style = #'slash
828 \override Stem #'transparent = ##t
831 All these plug-ins have to cooperate, and this is achieved with a
832 special plug-in, which must be marked with the keyword @code{\type}.
833 This should always be @code{Engraver_group}.
836 \type "Engraver_group"
844 \type "Engraver_group"
845 \consists "Note_heads_engraver"
846 \consists "Text_engraver"
847 \consists Pitch_squash_engraver
848 squashedPosition = #0
849 \override NoteHead #'style = #'slash
850 \override Stem #'transparent = ##t
856 Contexts form hierarchies. We want to hang the @code{ImproVoice}
857 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
858 modify the @code{Staff} definition with the @code{\accepts}
869 The opposite of @code{\accepts} is @code{\denies},
870 which is sometimes needed when reusing existing context definitions.
872 Putting both into a @code{\layout} block, like
882 \accepts "ImproVoice"
887 Then the output at the start of this subsection can be entered as
895 c c_"while playing :)"
902 @node Aligning contexts
903 @subsection Aligning contexts
905 New contexts may be aligned above or below existing contexts. This
906 could be useful in setting up a vocal staff (@rlearning{Vocal ensembles}) and
909 @c TODO Better example needed. Ref LM, and expand on it.
912 @funindex alignAboveContext
913 @funindex alignBelowContext
915 @lilypond[quote,ragged-right]
918 \relative c' \new Staff = "main" {
921 \new Staff \with { alignAboveContext = #"main" } \ossia
928 @cindex nested contexts
929 @cindex contexts, nested
934 Contexts like @code{PianoStaff} can contain other contexts
935 nested within them. Contexts which are acceptable for nesting
936 are defined by the @qq{accepts} list of a context. Contexts
937 which are not in this list are placed below the outer context
938 in the printed score.
939 For example, the @code{PianoStaff} context is defined by default
940 to accept @code{Staff} and @code{FiguredBass} contexts within
941 it, but not (for example) a @code{Lyrics} context. So in the
942 following structure the lyrics are placed below the piano staff
943 rather than between the two staves:
945 @lilypond[verbatim,quote,relative=1]
948 \new Staff { e4 d c2 }
949 \addlyrics { Three blind mice }
957 The @qq{accepts} list of a context can be modified to include
958 additional nested contexts, so if we wanted the lyrics to appear
959 between the two staves we could use:
961 @lilypond[verbatim,quote,relative=1]
962 \new PianoStaff \with { \accepts Lyrics }
964 \new Staff { e4 d c2 }
965 \addlyrics { Three blind mice }
973 The opposite of @code{\accepts} is @code{\denies}; this removes a
974 context from the @qq{accepts} list.
976 @node Explaining the Internals Reference
977 @section Explaining the Internals Reference
981 * Navigating the program reference::
982 * Layout interfaces::
983 * Determining the grob property::
984 * Naming conventions::
987 @node Navigating the program reference
988 @subsection Navigating the program reference
990 @c TODO remove this (it's in the LM)
991 @c Replace with more factual directions
993 Suppose we want to move the fingering indication in the fragment
996 @lilypond[quote,fragment,relative=2,verbatim]
1002 If you visit the documentation on fingering instructions (in
1003 @ref{Fingering instructions}), you will notice:
1008 Internals Reference: @rinternals{Fingering}.
1013 @c outdated info; probably will delete.
1015 This fragment points to two parts of the program reference: a page
1016 on @code{FingeringEvent} and one on @code{Fingering}.
1018 The page on @code{FingeringEvent} describes the properties of the music
1019 expression for the input @code{-2}. The page contains many links
1020 forward. For example, it says
1023 Accepted by: @rinternals{Fingering_engraver},
1027 That link brings us to the documentation for the Engraver, the
1031 This engraver creates the following layout objects: @rinternals{Fingering}.
1034 In other words, once the @code{FingeringEvent}s are interpreted, the
1035 @code{Fingering_engraver} plug-in will process them.
1039 @c I can't figure out what this is supposed to mean. -gp
1041 The @code{Fingering_engraver} is also listed to create
1042 @rinternals{Fingering} objects,
1044 @c old info? it doesn't make any sense to me with our current docs.
1046 second bit of information listed under @b{See also} in the Notation
1051 The programmer's reference is available as an HTML document. It is
1052 highly recommended that you read it in HTML form, either online or
1053 by downloading the HTML documentation. This section will be much more
1054 difficult to understand if you are using the
1058 Follow the link to @rinternals{Fingering}. At the top of the
1062 Fingering objects are created by: @rinternals{Fingering_engraver} and
1063 @rinternals{New_fingering_engraver}.
1066 By following related links inside the program reference, we can follow the
1067 flow of information within the program:
1071 @item @rinternals{Fingering}:
1072 @rinternals{Fingering} objects are created by:
1073 @rinternals{Fingering_engraver}
1075 @item @rinternals{Fingering_engraver}:
1076 Music types accepted: @rinternals{fingering-event}
1078 @item @rinternals{fingering-event}:
1079 Music event type @code{fingering-event} is in Music expressions named
1080 @rinternals{FingeringEvent}
1083 This path goes against the flow of information in the program: it
1084 starts from the output, and ends at the input event. You could
1085 also start at an input event, and read with the flow of
1086 information, eventually ending up at the output object(s).
1088 The program reference can also be browsed like a normal document. It
1089 contains chapters on
1091 @rinternals{Music definitions},
1094 @code{Music definitions}
1096 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1097 chapter lists all the definitions used and all properties that may be
1101 @node Layout interfaces
1102 @subsection Layout interfaces
1104 @cindex interface, layout
1105 @cindex layout interface
1108 The HTML page that we found in the previous section describes the
1109 layout object called @rinternals{Fingering}. Such an object is a
1110 symbol within the score. It has properties that store numbers (like
1111 thicknesses and directions), but also pointers to related objects. A
1112 layout object is also called a @emph{Grob}, which is short for Graphical
1113 Object. For more details about Grobs, see @rinternals{grob-interface}.
1115 The page for @code{Fingering} lists the definitions for the
1116 @code{Fingering} object. For example, the page says
1119 @code{padding} (dimension, in staff space):
1125 which means that the number will be kept at a distance of at least 0.5
1129 Each layout object may have several functions as a notational or
1130 typographical element. For example, the Fingering object
1131 has the following aspects
1135 Its size is independent of the horizontal spacing, unlike slurs or beams.
1138 It is a piece of text. Granted, it is usually a very short text.
1141 That piece of text is typeset with a font, unlike slurs or beams.
1144 Horizontally, the center of the symbol should be aligned to the
1145 center of the note head.
1148 Vertically, the symbol is placed next to the note and the staff.
1151 The vertical position is also coordinated with other superscript
1152 and subscript symbols.
1155 Each of these aspects is captured in so-called @emph{interface}s,
1156 which are listed on the @rinternals{Fingering} page at the bottom
1159 This object supports the following interfaces:
1160 @rinternals{item-interface},
1161 @rinternals{self-alignment-interface},
1162 @rinternals{side-position-interface}, @rinternals{text-interface},
1163 @rinternals{text-script-interface}, @rinternals{font-interface},
1164 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1167 Clicking any of the links will take you to the page of the respective
1168 object interface. Each interface has a number of properties. Some of
1169 them are not user-serviceable (@q{Internal properties}), but others
1172 We have been talking of @emph{the} @code{Fingering} object, but actually it
1173 does not amount to much. The initialization file (see
1174 @rlearning{Other sources of information})
1175 @file{scm/@/define@/-grobs@/.scm} shows the soul of the @q{object},
1180 (avoid-slur . around)
1181 (slur-padding . 0.2)
1182 (staff-padding . 0.5)
1183 (self-alignment-X . 0)
1184 (self-alignment-Y . 0)
1185 (script-priority . 100)
1186 (stencil . ,ly:text-interface::print)
1187 (direction . ,ly:script-interface::calc-direction)
1188 (font-encoding . fetaNumber)
1189 (font-size . -5) ; don't overlap when next to heads.
1190 (meta . ((class . Item)
1191 (interfaces . (finger-interface
1193 text-script-interface
1195 side-position-interface
1196 self-alignment-interface
1197 item-interface))))))
1201 As you can see, the @code{Fingering} object is nothing more than a
1202 bunch of variable settings, and the webpage in the Internals Reference
1203 is directly generated from this definition.
1206 @node Determining the grob property
1207 @subsection Determining the grob property
1209 @c TODO remove this (it's in the LM)
1210 @c Replace with more factual directions
1212 Recall that we wanted to change the position of the @b{2} in
1214 @lilypond[quote,fragment,relative=2,verbatim]
1220 Since the @b{2} is vertically positioned next to its note, we have to
1221 meddle with the interface associated with this positioning. This is
1222 done using @code{side-position-interface}. The page for this interface
1226 @code{side-position-interface}
1228 Position a victim object (this one) next to other objects (the
1229 support). The property @code{direction} signifies where to put the
1230 victim object relative to the support (left or right, up or down?)
1235 Below this description, the variable @code{padding} is described as
1240 (dimension, in staff space)
1242 Add this much extra space between objects that are next to each other.
1246 By increasing the value of @code{padding}, we can move the
1247 fingering away from the note head. The following command inserts
1248 3 staff spaces of white
1249 between the note and the fingering:
1251 \once \override Voice.Fingering #'padding = #3
1254 Inserting this command before the Fingering object is created,
1255 i.e., before @code{c2}, yields the following result:
1257 @lilypond[quote,relative=2,fragment,verbatim]
1258 \once \override Voice.Fingering #'padding = #3
1265 In this case, the context for this tweak is @code{Voice}. This
1266 fact can also be deduced from the program reference, for the page for
1267 the @rinternals{Fingering_engraver} plug-in says
1270 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1274 @node Naming conventions
1275 @subsection Naming conventions
1277 Another thing that is needed, is an overview of the various naming
1280 scheme functions: lowercase-with-hyphens (incl. one-word
1282 scheme functions: ly:plus-scheme-style
1283 music events, music classes and music properties:
1285 Grob interfaces: scheme-style
1286 backend properties: scheme-style (but X and Y!)
1287 contexts (and MusicExpressions and grobs): Capitalized or
1289 context properties: lowercaseFollowedByCamelCase
1291 Capitalized_followed_by_lowercase_and_with_underscores
1293 Which of these are conventions and which are rules?
1294 Which are rules of the underlying language, and which are
1298 @node Modifying properties
1299 @section Modifying properties
1301 @c TODO change the menu and subsection node names to use
1302 @c backslash once the new macro to handle the refs
1303 @c is available. Need to find and change all refs at
1304 @c the same time. -td
1307 * Overview of modifying properties::
1309 * The override command::
1310 * The tweak command::
1311 * set versus override::
1315 @node Overview of modifying properties
1316 @subsection Overview of modifying properties
1318 Each context is responsible for creating certain types of graphical
1319 objects. The settings used for printing these objects are also stored by
1320 context. By changing these settings, the appearance of objects can be
1323 The syntax for this is
1326 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1329 Here @var{name} is the name of a graphical object, like
1330 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1331 variable of the formatting system (@q{grob property} or @q{layout
1332 property}). The latter is a symbol, so it must be quoted. The
1333 subsection @ref{Modifying properties}, explains what to fill in
1334 for @var{name}, @var{property}, and @var{value}. Here we only
1335 discuss the functionality of this command.
1340 \override Staff.Stem #'thickness = #4.0
1344 makes stems thicker (the default is 1.3, with staff line thickness as a
1345 unit). Since the command specifies @code{Staff} as context, it only
1346 applies to the current staff. Other staves will keep their normal
1347 appearance. Here we see the command in action:
1349 @lilypond[quote,verbatim,relative=2,fragment]
1351 \override Staff.Stem #'thickness = #4.0
1357 The @code{\override} command changes the definition of the @code{Stem}
1358 within the current @code{Staff}. After the command is interpreted
1359 all stems are thickened.
1361 Analogous to @code{\set}, the @var{context} argument may be left out,
1362 causing the default context @code{Voice} to be used. Adding
1363 @code{\once} applies the change during one timestep only.
1365 @lilypond[quote,fragment,verbatim,relative=2]
1367 \once \override Stem #'thickness = #4.0
1372 The @code{\override} must be done before the object is
1373 started. Therefore, when altering @emph{Spanner} objects such as slurs
1374 or beams, the @code{\override} command must be executed at the moment
1375 when the object is created. In this example,
1377 @lilypond[quote,fragment,verbatim,relative=2]
1378 \override Slur #'thickness = #3.0
1380 \override Beam #'thickness = #0.6
1385 the slur is fatter but the beam is not. This is because the command for
1386 @code{Beam} comes after the Beam is started, so it has no effect.
1388 Analogous to @code{\unset}, the @code{\revert} command for a context
1389 undoes an @code{\override} command; like with @code{\unset}, it only
1390 affects settings that were made in the same context. In other words, the
1391 @code{\revert} in the next example does not do anything.
1394 \override Voice.Stem #'thickness = #4.0
1395 \revert Staff.Stem #'thickness
1398 Some tweakable options are called @q{subproperties} and reside inside
1399 properties. To tweak those, use commands of the form
1401 @c leave this as a long long
1403 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1410 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1415 Internals: @rinternals{OverrideProperty}, @rinternals{RevertProperty},
1416 @rinternals{PropertySet}, @rinternals{Backend}, and
1417 @rinternals{All layout objects}.
1422 The back-end is not very strict in type-checking object properties.
1423 Cyclic references in Scheme values for properties can cause hangs
1424 or crashes, or both.
1428 @node The set command
1429 @subsection The @code{\set} command
1433 @cindex changing properties
1435 Each context can have different @emph{properties}, variables contained
1436 in that context. They can be changed during the interpretation step.
1437 This is achieved by inserting the @code{\set} command in the music,
1440 \set @var{context}.@var{prop} = #@var{value}
1444 @lilypond[quote,verbatim,relative=2,fragment]
1446 \set Score.skipBars = ##t
1450 This command skips measures that have no notes. The result is that
1451 multi-rests are condensed. The value assigned is a Scheme object. In
1452 this case, it is @code{#t}, the boolean True value.
1454 If the @var{context} argument is left out, then the current bottom-most
1455 context (typically @code{ChordNames}, @code{Voice}, or
1456 @code{Lyrics}) is used. In this example,
1458 @lilypond[quote,verbatim,relative=2,fragment]
1460 \set autoBeaming = ##f
1465 the @var{context} argument to @code{\set} is left out, so automatic
1466 beaming is switched off in the current @rinternals{Voice}. Note that
1467 the bottom-most context does not always contain the property that you
1468 wish to change -- for example, attempting to set the @code{skipBars}
1469 property (of the bottom-most context, in this case @code{Voice}) will
1472 @lilypond[quote,verbatim,relative=2,fragment]
1478 Contexts are hierarchical, so if a bigger context was specified, for
1479 example @code{Staff}, then the change would also apply to all
1480 @code{Voice}s in the current stave. The change is applied
1481 @q{on-the-fly}, during the music, so that the setting only affects the
1482 second group of eighth notes.
1486 There is also an @code{\unset} command,
1488 \unset @var{context}.@var{prop}
1492 which removes the definition of @var{prop}. This command removes
1493 the definition only if it is set in @var{context}, so
1496 \set Staff.autoBeaming = ##f
1500 introduces a property setting at @code{Staff} level. The setting also
1501 applies to the current @code{Voice}. However,
1504 \unset Voice.autoBeaming
1508 does not have any effect. To cancel this setting, the @code{\unset}
1509 must be specified on the same level as the original @code{\set}. In
1510 other words, undoing the effect of @code{Staff.autoBeaming = ##f}
1513 \unset Staff.autoBeaming
1516 Like @code{\set}, the @var{context} argument does not have to be
1517 specified for a bottom context, so the two statements
1520 \set Voice.autoBeaming = ##t
1521 \set autoBeaming = ##t
1529 Settings that should only apply to a single time-step can be entered
1530 with @code{\once}, for example in
1532 @lilypond[quote,verbatim,relative=2,fragment]
1534 \once \set fontSize = #4.7
1539 the property @code{fontSize} is unset automatically after the second
1542 A full description of all available context properties is in the
1543 program reference, see
1545 @rinternals{Tunable context properties}.
1548 Translation @expansion{} Tunable context properties.
1553 @node The override command
1554 @subsection The @code{\override} command
1556 Commands which change output generally look like
1559 \override Voice.Stem #'thickness = #3.0
1563 To construct this tweak we must determine these bits of information:
1566 @item the context: here @code{Voice}.
1567 @item the layout object: here @code{Stem}.
1568 @item the layout property: here @code{thickness}.
1569 @item a sensible value: here @code{3.0}.
1572 Some tweakable options are called @q{subproperties} and reside inside
1573 properties. To tweak those, use commands in the form
1576 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1579 @cindex internal documentation
1580 @cindex finding graphical objects
1581 @cindex graphical object descriptions
1584 @cindex internal documentation
1586 For many properties, regardless of the data type of the property, setting the
1587 property to false ( @code{##f} ) will result in turning it off, causing
1588 LilyPond to ignore that property entirely. This is particularly useful for
1589 turning off grob properties which may otherwise be causing problems.
1591 We demonstrate how to glean this information from the notation manual
1592 and the program reference.
1595 @node The tweak command
1596 @subsection The @code{\tweak} command
1601 In some cases, it is possible to take a short-cut for tuning
1602 graphical objects. For objects that are created directly from
1603 an item in the input file, you can use the @code{\tweak} command.
1606 @lilypond[relative=2,verbatim]
1611 \tweak #'duration-log #1
1614 -\tweak #'padding #8
1618 @cindex chord, modifying one note in
1620 But the main use of the @code{\tweak} command is to modify just
1621 one of a number of notation elements which start at the same musical
1622 moment, like the notes of a chord, or tuplet brackets which start
1625 For an introduction to the syntax and uses of the tweak command
1626 see @rlearning{Tweaking methods}.
1628 The @code{\tweak} command sets a property in the following object
1629 directly, without requiring the grob name or context to be
1630 specified. For this to work, it is necessary for the @code{\tweak}
1631 command to remain immediately adjacent to the object to which it is
1632 to apply after the input file has been converted to a music stream.
1633 This is often not the case, as many additional elements are inserted
1634 into the music stream implicitly. For example, when a note which is
1635 not part of a chord is processed, LilyPond implicitly inserts a
1636 @code{ChordEvent} event before the note, so separating the tweak
1637 from the note. However, if chord symbols are placed round the
1638 tweak and the note, the @code{\tweak} command comes after the
1639 @code{ChordEvent} in the music stream, so remaining adjacent to the
1640 note, and able to modify it.
1644 @lilypond[relative=2,verbatim,quote]
1645 <\tweak #'color #red c>4
1651 @lilypond[relative=2,verbatim,quote]
1652 \tweak #'color #red c4
1655 When several similar items are placed at the same musical moment,
1656 the @code{\override} command cannot be used to modify just one of
1657 them -- this is where the @code{\tweak} command must be used.
1658 Items which may appear more than once at the same musical moment
1659 include the following:
1661 @c TODO expand to include any further uses of \tweak
1663 @item note heads of notes inside a chord
1664 @item articulation signs on a single note
1665 @item ties between notes in a chord
1666 @item tuplet brackets starting at the same time
1669 @c TODO add examples of these
1672 and @code{\tweak} may be used to modify any single occurrence of
1675 Notably the @code{\tweak} command cannot be used to modify stems,
1676 beams or accidentals directly, since these are generated later by
1677 note heads, rather than by music elements in the input stream.
1678 Nor can a @code{\tweak} command be used to modify clefs or time
1679 signatures, since these become separated from any preceding
1680 @code{\tweak} command in the input stream by the automatic
1681 insertion of extra elements required to specify the context.
1683 But the @code{\tweak} command can be used as an alternative to
1684 the @code{\override} command to modify those notational elements
1685 that do not cause any additional implicit elements to be added
1686 before them in the music stream. For example, slurs may be
1687 modified in this way:
1689 @lilypond[verbatim,quote,relative=1]
1690 c-\tweak #'thickness #5 ( d e f)
1693 Also several @code{\tweak} commands may be placed before a
1694 notational element -- all affect it:
1696 @lilypond[verbatim,quote,relative=1]
1698 -\tweak #'style #'dashed-line
1699 -\tweak #'dash-fraction #0.2
1700 -\tweak #'thickness #3
1701 -\tweak #'color #red
1706 The music stream which is generated from a section of an input file,
1707 including any automatically inserted elements, may be examined,
1708 see @ref{Displaying music expressions}. This may be helpful in
1709 determining what may be modified by a @code{\tweak} command.
1714 @rlearning{Tweaking methods}.
1717 @ref{Displaying music expressions}.
1722 @cindex tweaks in a variable
1723 The @code{\tweak} command cannot be used inside a variable.
1725 @cindex tweaks in lyrics
1726 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1728 @cindex tweaking control points
1729 @cindex control points, tweaking
1731 The @code{\tweak} command cannot be used to modify the control
1732 points of just one of several ties in a chord, other than the first
1733 one encountered in the input file.
1735 @node set versus override
1736 @subsection @code{\set} vs. @code{\override}
1738 We have seen two methods of changing properties: @code{\set} and
1739 @code{\override}. There are actually two different kinds of
1742 Contexts can have properties, which are usually named in
1743 @code{studlyCaps}. They mostly control the translation from
1744 music to notation, eg. @code{localKeySignature} (for determining
1745 whether to print accidentals), @code{measurePosition} (for
1746 determining when to print a bar line). Context properties can
1747 change value over time while interpreting a piece of music;
1748 @code{measurePosition} is an obvious example of
1749 this. Context properties are modified with @code{\set}.
1751 There is a special type of context property: the element
1752 description. These properties are named in @code{StudlyCaps}
1753 (starting with capital letters). They contain the
1754 @q{default settings} for said graphical object as an
1755 association list. See @file{scm/@/define@/-grobs@/.scm}
1756 to see what kind of settings there are. Element descriptions
1757 may be modified with @code{\override}.
1759 @code{\override} is actually a shorthand;
1762 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1766 is more or less equivalent to
1768 @c leave this long line -gp
1770 \set @var{context}.@var{name} #'@var{property} = #(cons (cons '@var{property} @var{value}) <previous value of @var{context})
1773 The value of @code{context} (the alist) is used to initialize
1774 the properties of individual grobs. Grobs also have
1775 properties, named in Scheme style, with
1776 @code{dashed-words}. The values of grob properties change
1777 during the formatting process: formatting basically amounts
1778 to computing properties using callback functions.
1780 @code{fontSize} is a special property: it is equivalent to
1781 entering @code{\override ... #'font-size} for all pertinent
1782 objects. Since this is a common change, the special
1783 property (modified with @code{\set}) was created.
1786 @node Useful concepts and properties
1787 @section Useful concepts and properties
1792 * Direction and placement::
1793 * Context layout order::
1794 * Distances and measurements::
1795 * Staff symbol properties::
1797 * Visibility of objects::
1799 * Rotating objects::
1803 @subsection Input modes
1805 The way in which the notation contained within an input file is
1806 interpreted is determined by the current input mode.
1810 This is activated with the @code{\chordmode} command, and causes
1811 input to be interpreted with the syntax of chord notation, see
1812 @ref{Chord notation}. Chords are rendered as notes on a staff.
1814 Chord mode is also activated with the @code{\chords} command.
1815 This also creates a new @code{ChordNames} context and
1816 causes the following input to be interpreted with the syntax of
1817 chord notation and rendered as chord names in the @code{ChordNames}
1818 context, see @ref{Printing chord names}.
1822 This is activated with the @code{\drummode} command, and causes
1823 input to be interpreted with the syntax of drum notation, see
1824 @ref{Basic percussion notation}.
1826 Drum mode is also activated with the @code{\drums} command.
1827 This also creates a new @code{DrumStaff} context and causes the
1828 following input to be interpreted with the syntax of drum notation
1829 and rendered as drum symbols on a drum staff, see @ref{Basic
1830 percussion notation}.
1832 @strong{Figure mode}
1834 This is activated with the @code{\figuremode} command, and causes
1835 input to be interpreted with the syntax of figured bass, see
1836 @ref{Entering figured bass}.
1838 Figure mode is also activated with the @code{\figures} command.
1839 This also creates a new @code{FiguredBass} context and causes the
1840 following input to be interpreted with the figured bass syntax
1841 and rendered as figured bass symbols in the @code{FiguredBass}
1842 context, see @ref{Introduction to figured bass}.
1844 @strong{Fret and tab modes}
1846 There are no special input modes for entering fret and tab symbols.
1848 To create tab diagrams, enter notes or chords in note mode and
1849 render them in a @code{TabStaff} context, see
1850 @ref{Default tablatures}.
1852 To create fret diagrams above a staff, you have two choices.
1853 You can either use the @code{FretBoards} context (see
1854 @ref{Automatic fret diagrams} or you can enter them as a markup
1855 above the notes using the @code{\fret-diagram} command (see
1856 @ref{Fret diagram markups}).
1858 @strong{Lyrics mode}
1860 This is activated with the @code{\lyricmode} command, and causes
1861 input to be interpreted as lyric syllables with optional durations
1862 and associated lyric modifiers, see @ref{Vocal music}.
1864 Lyric mode is also activated with the @code{\addlyrics} command.
1865 This also creates a new @code{Lyrics} context and an implicit
1866 @code{\lyricsto} command which associates the following lyrics
1867 with the preceding music.
1869 @strong{Markup mode}
1871 This is activated with the @code{\markup} command, and causes
1872 input to be interpreted with the syntax of markup, see
1873 @ref{Text markup commands}.
1875 @c silly work-around for texinfo broken-ness
1876 @c (@strong{Note...} causes a spurious cross-reference in Info)
1879 This is the default mode or it may be activated with the
1880 @code{\notemode} command. Input is interpreted as pitches,
1881 durations, markup, etc and typeset as musical notation on a staff.
1883 It is not normally necessary to specify note mode explicitly, but
1884 it may be useful to do so in certain situations, for example if you
1885 are in lyric mode, chord mode or any other mode and want to insert
1886 something that only can be done with note mode syntax.
1888 For example, to indicate dynamic markings for the verses of a
1889 choral pieces it is necessary to enter note mode to interpret
1892 @lilypond[verbatim,relative=2,quote]
1895 \notemode{\set stanza = \markup{ \dynamic f 1. } }
1899 \notemode{\set stanza = \markup{ \dynamic p 2. } }
1906 @node Direction and placement
1907 @subsection Direction and placement
1909 In typesetting music the direction and placement of many items is
1910 a matter of choice. For example, the stems of notes can
1911 be directed up or down; lyrics, dynamics, and other expressive
1912 marks may be placed above or below the staff; text may be aligned
1913 left, right or center; etc. Most of these choices may be left to
1914 be determined automatically by LilyPond, but in some cases it may
1915 be desirable to force a particular direction or placement.
1917 @strong{Articulation direction indicators}
1919 By default some directions are always up or always down (e.g.
1920 dynamics or fermata), while other things can alternate between
1921 up or down based on the stem direction (like slurs or accents).
1923 @c TODO Add table showing these
1925 The default action may be overridden by prefixing the articulation
1926 by a @emph{direction indicator}. Three direction indicators are
1927 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
1928 and @code{-} (meaning @qq{use default direction}). The direction
1929 indicator can usually be omitted, in which case @code{-} is assumed,
1930 but a direction indicator is @strong{always} required before
1933 @item @code{\tweak} commands
1934 @item @code{\markup} commands
1935 @item @code{\tag} commands
1936 @item string markups, e.g. -"string"
1937 @item fingering instructions, e.g. @code{-1}
1938 @item articulation shortcuts, e.g. @code{-.}, @code{->}, @code{--}
1941 Direction indicators affect only the next note:
1943 @lilypond[verbatim,quote,relative=2]
1950 @strong{The direction property}
1952 The position or direction of many layout objects is controlled
1953 by the @code{direction} property.
1955 The value of the @code{direction} property may be
1956 set to @code{1}, meaning @qq{up} or @qq{above}, or to @code{-1},
1957 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
1958 @code{DOWN} may be used instead of @code{1} and @code{-1}
1959 respectively. The default direction may be specified by setting
1960 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
1961 in many cases predefined commands
1962 exist to specify the direction. These are all of the form
1965 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
1968 where @code{xxxNeutral} means @qq{use the default direction}.
1969 See @rlearning{Within-staff objects}.
1971 In a few cases, arpeggio being the only common example, the value
1972 of the @code{direction} property specifies whether the object
1973 is to be placed to the right or left of the parent object. In
1974 this case @code{-1} or @code{LEFT} means @qq{to the left} and
1975 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
1976 or @code{CENTER} means @qq{use the default} direction, as before.
1979 These all have side-axis set to #X
1980 AmbitusAccidental - direction has no effect
1982 StanzaNumber - not tried
1983 TrillPitchAccidental - not tried
1984 TrillPitchGroup - not tried
1987 These indications affect all notes until they are cancelled.
1989 @lilypond[verbatim,quote,relative=2]
1999 @node Context layout order
2000 @subsection Context layout order
2002 @cindex contexts, layout order
2004 Contexts are normally positioned in a system from top to bottom
2005 in the order in which they are encountered in the input file. When
2006 contexts are nested, the outer context will include inner nested
2007 contexts as specified in the input file, provided the inner contexts
2008 are included in the outer context's @qq{accepts} list. Nested
2009 contexts which are not included in the outer context's @qq{accepts}
2010 list will be repositioned below the outer context rather than nested
2013 Note that a context will be silently created implicitly if a command
2014 is encountered when there is no suitable context available to
2015 contain it. This can give rise to unexpected new staves or scores.
2017 @c TODO add example of this
2019 The default order in which contexts are laid out and the
2020 @qq{accepts} list can be changed, see @ref{Aligning contexts}.
2023 @node Distances and measurements
2024 @subsection Distances and measurements
2026 @cindex distances, absolute
2027 @cindex distances, scaled
2034 Distances in LilyPond are of two types: absolute and scaled.
2036 Absolute distances are used for specifying margins, indents, and
2037 other page layout details, and are by default specified in
2038 millimeters. Distances may be specified in other units by
2039 following the quantity by @code{\mm}, @code{\cm},
2040 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27
2041 of an inch). Page layout distances can also be specified in
2042 scalable units (see the following paragraph) by appending
2043 @code{\staff-space} to the quantity.
2044 Page layout is described in detail in @ref{Page formatting}.
2046 Scaled distances are always specified in units of the staff-space
2047 or, rarely, the half staff-space. The staff-space is the distance
2048 between two adjacent staff lines. The default value can be changed
2049 globally by setting the global staff size, or it can be overridden
2050 locally by changing the @code{staff-space} property of
2051 @code{StaffSymbol}. Scaled distances automatically scale with any
2052 change to the either the global staff size or the
2053 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2054 automatically only with changes to the global staff size.
2055 The global staff size thus enables the overall size of a rendered
2056 score to be easily varied. For the methods of setting the global
2057 staff size see @ref{Setting the staff size}.
2061 If just a section of a score needs to be rendered to a different
2062 scale, for example an ossia section or a footnote, the global staff
2063 size cannot simply be changed as this would affect the entire score.
2064 In such cases the change in size is made by overriding both the
2065 @code{staff-space} property of @code{StaffSymbol} and the size of
2066 the fonts. A Scheme function, @code{magstep}, is available to
2067 convert from a font size change to the equivalent change in
2068 @code{staff-space}. For an explanation and an example of its use,
2069 see @rlearning{Length and thickness of objects}.
2074 @rlearning{Length and thickness of objects}.
2077 @ref{Page formatting},
2078 @ref{Setting the staff size}.
2081 @node Staff symbol properties
2082 @subsection Staff symbol properties
2084 @cindex adjusting staff symbol
2085 @cindex drawing staff symbol
2086 @cindex staff symbol, setting of
2088 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2089 @c Need to think of uses for these properties. Eg 'line-positions
2090 @c is used in a snippet to thicken centre line.
2091 @c If retained, add @ref to here in 1.6.2 -td
2093 The vertical position of staff lines and the number of staff lines
2094 can be defined at the same time. As the following example shows,
2095 note positions are not influenced by the staff line positions.
2097 @warning{The @code{'line-positions} property overrides the
2098 @code{'line-count} property. The number of staff lines is
2099 implicitly defined by the number of elements in the list of values
2100 for @code{'line-positions}.}
2102 @lilypond[verbatim,quote,relative=1]
2104 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
2109 The width of a staff can be modified. The units are staff
2110 spaces. The spacing of objects inside the staff is not affected by
2113 @lilypond[verbatim,quote,relative=1]
2115 \override StaffSymbol #'width = #23
2122 @subsection Spanners
2124 Many objects of musical notation extend over several notes or even
2125 several bars. Examples are slurs, beams, tuplet brackets, volta
2126 repeat brackets, crescendi, trills, and glissandi. Such objects
2127 are collectively called @qq{spanners}, and have special properties to control
2128 their appearance and behaviour. Some of these properties are common
2129 to all spanners; others are restricted to a sub-set of the spanners.
2131 All spanners support the @code{spanner-interface}. A few, esentially
2132 those that draw a straight line between the two objects, support in
2133 addition the @code{line-spanner-interface}.
2135 @unnumberedsubsubsec Using the @code{spanner-interface}
2137 This interface provides two properties that apply to several spanners.
2139 @strong{@i{The @code{minimum-length} property}}
2141 The minimum length of the spanner is specified by the
2142 @code{minimum-length} property. Increasing this usually has the
2143 necessary effect of increasing the spacing of the notes between the
2144 two end points. However, this override has no effect on
2145 many spanners, as their length is determined by other considerations.
2146 A few examples where it is effective are shown below.
2156 Works as long as callback is made:
2160 Works not at all for:
2169 @lilypond[verbatim,quote,relative=2]
2172 % increase the length of the tie
2173 -\tweak #'minimum-length #5
2177 @lilypond[verbatim,quote,relative=2]
2179 \compressFullBarRests
2181 % increase the length of the rest bar
2182 \once \override MultiMeasureRest #'minimum-length = #20
2187 @lilypond[verbatim,quote,relative=2]
2189 % increase the length of the hairpin
2190 \override Hairpin #'minimum-length = #20
2194 This override can also be used to increase the length of slurs and
2197 @lilypond[verbatim,quote,relative=2]
2200 -\tweak #'minimum-length #5
2205 -\tweak #'minimum-length #5
2209 For some layout objects, the @code{minimum-length} property becomes
2210 effective only if the @code{set-spacing-rods} procedure is called
2211 explicitly. To do this, the @code{springs-and-rods} property should
2212 be set to @code{ly:spanner::set-spacing-rods}. For example,
2213 the minimum length of a glissando has no effect unless the
2214 @code{springs-and-rods} property is set:
2216 @lilypond[verbatim,quote,relative=1]
2220 % not effective alone
2221 \once \override Glissando #'minimum-length = #20
2224 % effective only when both overrides are present
2225 \once \override Glissando #'minimum-length = #20
2226 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2230 The same is true of the @code{Beam} object:
2232 @lilypond[verbatim,quote,relative=1]
2233 % not effective alone
2234 \once \override Beam #'minimum-length = #20
2237 % effective only when both overrides are present
2238 \once \override Beam #'minimum-length = #20
2239 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2243 @strong{@i{The @code{to-barline} property}}
2245 The second useful property of the @code{spanner-interface} is
2246 @code{to-barline}. By default this is true, causing hairpins and
2247 other spanners which are terminated on the first note of a measure to
2248 end instead on the immediately preceding bar line. If set to false,
2249 the spanner will extend beyond the bar line and end on the note
2252 @lilypond[verbatim,quote,relative=2]
2253 a \< a a a a \! a a a \break
2254 \override Hairpin #'to-barline = ##f
2255 a \< a a a a \! a a a
2258 This property is not effective for all spanners. For example,
2259 seting it to @code{#t} has no effect on slurs or phrasing slurs
2260 or on other spanners for which terminating on the bar line would
2263 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2265 Objects which support the @code{line-spanner-interface} include
2268 @item @code{DynamicTextSpanner}
2269 @item @code{Glissando}
2270 @item @code{TextSpanner}
2271 @item @code{TrillSpanner}
2272 @item @code{VoiceFollower}
2275 The routine responsible for drawing the stencils for these spanners is
2276 @code{ly:line-interface::print}. This routine determines the
2277 exact location of the two end points and draws a line
2278 between them, in the style requested. The locations of the two
2279 end points of the spanner are computed on-the-fly, but it is
2280 possible to override their Y-coordinates. The
2281 properties which need to be specified are nested
2282 two levels down within the property hierarchy, but the syntax of
2283 the @code{\override} command is quite simple:
2285 @lilypond[relative=2,quote,verbatim]
2287 \once \override Glissando #'(bound-details left Y) = #3
2288 \once \override Glissando #'(bound-details right Y) = #-2
2292 The units for the @code{Y} property are @code{staff-space}s,
2293 with the center line of the staff being the zero point.
2294 For the glissando, this is the value for @code{Y} at the
2295 X-coordinate corresponding to the center point of each note head,
2296 if the line is imagined to be extended to there.
2298 If @code{Y} is not set, the value is computed from the vertical
2299 position of the corresponding attachment point of the spanner.
2301 In case of a line break, the values for the end points are
2302 specified by the @code{left-broken} and @code{right-broken}
2303 sub-lists of @code{bound-details}. For example:
2305 @lilypond[relative=2,ragged-right,verbatim,fragment]
2306 \override Glissando #'breakable = ##t
2307 \override Glissando #'(bound-details right-broken Y) = #-3
2308 c1 \glissando \break
2313 A number of further properties of the @code{left} and
2314 @code{right} sub-lists of the @code{bound-details} property
2315 may be modified in the same way as @code{Y}:
2319 This sets the Y-coordinate of the end point, in @code{staff-space}s
2320 offset from the staff center line. By default, it is the center of
2321 the bound object, so a glissando points to the vertical center of
2324 For horizontal spanners, such as text spanners and trill spanners,
2325 it is hardcoded to 0.
2328 This determines where the line starts and ends in the X-direction,
2329 relative to the bound object. So, a value of @code{-1} (or
2330 @code{LEFT}) makes the line start/end at the left side of the note
2331 head it is attached to.
2334 This is the absolute X-coordinate of the end point. It is usually
2335 computed on the fly, and overriding it has little useful effect.
2338 Line spanners may have symbols at the beginning or end, which is
2339 contained in this sub-property. This is for internal use; it is
2340 recommended that @code{text} be used instead.
2343 This is a markup that is evaluated to yield the stencil. It is used
2344 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2346 @lilypond[quote,ragged-right,fragment,relative=2,verbatim]
2347 \override TextSpanner #'(bound-details left text)
2348 = \markup { \small \bold Slower }
2349 c2\startTextSpan b c a\stopTextSpan
2352 @item stencil-align-dir-y
2353 @item stencil-offset
2354 Without setting one of these, the stencil is simply put at the
2355 end-point, centered on the line, as defined by the @code{X} and
2356 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2357 or @code{stencil-offset} will move the symbol at the edge vertically
2358 relative to the end point of the line:
2360 @lilypond[relative=1,fragment,verbatim]
2361 \override TextSpanner
2362 #'(bound-details left stencil-align-dir-y) = #-2
2363 \override TextSpanner
2364 #'(bound-details right stencil-align-dir-y) = #UP
2366 \override TextSpanner
2367 #'(bound-details left text) = #"ggg"
2368 \override TextSpanner
2369 #'(bound-details right text) = #"hhh"
2370 c4^\startTextSpan c c c \stopTextSpan
2373 Note that negative values move the text @emph{up}, contrary to the
2374 effect that might be expected, as a value of @code{-1} or
2375 @code{DOWN} means align the @emph{bottom} edge of the text with
2376 the spanner line. A value of @code{1} or @code{UP} aligns
2377 the top edge of the text with the spanner line.
2380 Setting this sub-property to @code{#t} produces an arrowhead at the
2384 This sub-property controls the space between the specified
2385 end point of the line and the actual end. Without padding, a
2386 glissando would start and end in the center of each note head.
2390 The music function @code{\endSpanners} terminates the spanner
2391 which starts on the immediately following note prematurely. It
2392 is terminated after exactly one note, or at the following bar line
2393 if @code{to-barline} is true and a bar line occurs before the next
2396 @lilypond[verbatim,quote,ragged-right,relative=2,fragment]
2398 c2 \startTextSpan c2 c2
2403 When using @code{\endSpanners} it is not necessary to close
2404 \startTextSpan with \stopTextSpan, nor is it necessary to close
2405 hairpins with @code{\!}.
2409 Internals Reference: @rinternals{TextSpanner},
2410 @rinternals{Glissando}, @rinternals{VoiceFollower},
2411 @rinternals{TrillSpanner},
2412 @rinternals{line-spanner-interface}.
2415 @node Visibility of objects
2416 @subsection Visibility of objects
2418 @cindex objects, visibility of
2419 @cindex grobs, visibility of
2420 @cindex visibility of objects
2422 There are four main ways in which the visibility of layout objects
2423 can be controlled: their stencil can be removed, they can be made
2424 transparent, they can be colored white, or their
2425 @code{break-visibility} property can be overridden. The first
2426 three apply to all layout objects; the last to just a few -- the
2427 @emph{breakable} objects. The Learning Manual introduces these
2428 four techniques, see @rlearning{Visibility and color of objects}.
2430 There are also a few other techniques which are specific to
2431 certain layout objects. These are covered under Special
2435 * Removing the stencil::
2436 * Making objects transparent::
2437 * Painting objects white::
2438 * Using break-visibility::
2439 * Special considerations::
2443 @node Removing the stencil
2444 @unnumberedsubsubsec Removing the stencil
2446 @cindex stencil, removing
2448 Every layout object has a stencil property. By default this is set
2449 to the specific function which draws that object. If this property
2450 is overridden to @code{#f} no function will be called and the object
2451 will not be drawn. The default action can be recovered with
2454 @lilypond[quote,verbatim,relative=1]
2456 \override Score.BarLine #'stencil = ##f
2458 \revert Score.BarLine #'stencil
2462 @node Making objects transparent
2463 @unnumberedsubsubsec Making objects transparent
2465 @cindex transparent, making objects
2467 Every layout object has a transparent property which by default is
2468 set to @code{#f}. If set to @code{#t} the object still occupies
2469 space but is made invisible.
2471 @lilypond[quote,verbatim,relative=2]
2473 \once \override NoteHead #'transparent = ##t
2477 @node Painting objects white
2478 @unnumberedsubsubsec Painting objects white
2480 @cindex objects, coloring
2481 @cindex coloring objects
2483 @cindex printing order
2484 @cindex overwriting objects
2485 @cindex objects, overwriting
2486 @cindex grobs, overwriting
2488 Every layout object has a color property which by default is set
2489 to @code{black}. If this is overridden to @code{white} the object
2490 will be indistinguishable from the white background. However,
2491 if the object crosses other objects the color of the crossing
2492 points will be determined by the order in which they are drawn,
2493 and this may leave a ghostly image of the white object, as shown
2496 @lilypond[quote,verbatim,relative=2]
2497 \override Staff.Clef #'color = #white
2501 This may be avoided by changing the order of printing the objects.
2502 All layout objects have a @code{layer} property which should be set
2503 to an integer. Objects with the lowest value of @code{layer} are
2504 drawn first, then objects with progressively higher values are drawn,
2505 so objects with higher values overwrite objects with lower values.
2506 By default most objects are assigned a @code{layer} value of
2507 @code{1}, although a few objects, including @code{StaffSymbol} and
2508 @code{BarLine}, are assigned a value of @code{0}. The order of
2509 printing objects with the same value of @code{layer} is indeterminate.
2511 In the example above the white clef, with a default @code{layer}
2512 value of @code{1}, is drawn after the staff lines (default
2513 @code{layer} value @code{0}), so overwriting them. To change this,
2514 the @code{Clef} object must be given in a lower value of
2515 @code{layer}, say @code{-1}, so that it is drawn earlier:
2517 @lilypond[quote,verbatim,relative=2]
2518 \override Staff.Clef #'color = #white
2519 \override Staff.Clef #'layer = #-1
2523 @node Using break-visibility
2524 @unnumberedsubsubsec Using break-visibility
2526 @c TODO Add making other objects breakable
2528 @cindex break-visibility
2530 Most layout objects are printed only once, but some like
2531 bar lines, clefs, time signatures and key signatures, may need
2532 to be printed twice when a line break occurs -- once at the end
2533 of the line and again at the start of the next line. Such
2534 objects are called @emph{breakable}, and have a property, the
2535 @code{break-visibility} property to control their visibility
2536 at the three positions in which they may appear -- at the
2537 start of a line, within a line if they are changed, and at the
2538 end of a line if a change takes place there.
2540 For example, the time signature
2541 by default will be printed at the start of the first line, but
2542 nowhere else unless it changes, when it will be printed at the
2543 point at which the change occurs. If this change occurs at the
2544 end of a line the new time signature will be printed at the start
2545 of the next line and a cautionary time signature will be printed
2546 at the end of the previous line as well.
2548 This behaviour is controlled by the @code{break-visibility}
2549 property, which is explained in
2550 @c Leave this ref on a newline - formats incorrectly otherwise -td
2551 @rlearning{Visibility and color of objects}. This property takes
2552 a vector of three booleans which, in order, determine whether the
2553 object is printed at the end of, within the body of, or at the
2554 beginning of a line. Or to be more precise, before a line break,
2555 where there is no line break, or after a line break.
2557 Alternatively, these eight combinations may be specified
2558 by pre-defined functions, defined in @file{scm/output-lib.scm},
2559 where the last three columns indicate whether the layout objects
2560 will be visible in the positions shown at the head of the columns:
2562 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2563 @headitem Function @tab Vector @tab Before @tab At no @tab After
2564 @headitem form @tab form @tab break @tab break @tab break
2566 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2567 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2568 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2569 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2570 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2571 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2572 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2573 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2576 The default settings of @code{break-visibility} depend on the
2577 layout object. The following table shows all the layout objects
2578 of interest which are affected by @code{break-visibility} and the
2579 default setting of this property:
2581 @multitable @columnfractions .3 .3 .4
2583 @headitem Layout object @tab Usual context @tab Default setting
2585 @c omit Ambitus as it appears not to be affected by break-visibility -td
2586 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2587 @item @code{BarLine} @tab @code{Score} @tab calculated
2588 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2589 @c omit the following item until it can be explained -td
2590 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2591 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2592 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2593 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2594 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2595 @c omit KeyCancellation until it can be explained -td
2596 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2597 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2598 @c omit LeftEdge until it can be explained -td
2599 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2600 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2601 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2602 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2606 The example below shows the use of the vector form to control the
2607 visibility of barlines:
2609 @lilypond[quote,verbatim,relative=1,ragged-right]
2612 % Remove bar line at the end of the current line
2613 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2619 Although all three components of the vector used to override
2620 @code{break-visibility} must be present, not all of them are
2621 effective with every layout object, and some combinations may
2622 even give errors. The following limitations apply:
2625 @item Bar lines cannot be printed at start of line.
2626 @item A bar number cannot be printed at the start of the first
2627 line unless it is set to be different from 1.
2628 @item Clef -- see below
2629 @item Double percent repeats are either all printed or all
2630 suppressed. Use begin-of line-invisible to print and
2631 all-invisible to suppress.
2632 @item Key signature -- see below
2633 @item OctavateEight -- see below
2636 @node Special considerations
2637 @unnumberedsubsubsec Special considerations
2639 @strong{@emph{Visibility following explicit changes}}
2641 @cindex key signature, visibility following explicit change
2642 @cindex explicitKeySignatureVisibility
2643 @cindex clef, visibility following explicit change
2644 @cindex explicitClefVisibility
2646 The @code{break-visibility} property controls the visibility of
2647 key signatures and changes of clef only at the start of lines,
2648 i.e. after a break. It has no effect on the visibility of the
2649 key signature or clef following an explicit key change or an
2650 explicit clef change within or at the end of a line. In the
2651 following example the key signature following the explicit change
2652 to B-flat major is still visible, even though @code{all-invisible}
2655 @lilypond[quote,verbatim,relative=1,ragged-right]
2658 % Try to remove all key signatures
2659 \override Staff.KeySignature #'break-visibility = #all-invisible
2667 The visibility of such explicit key signature and clef changes is
2668 controlled by the @code{explicitKeySignatureVisibility} and
2669 @code{explicitClefVisibility} properties. These are the equivalent
2670 of the @code{break-visibility} property and both take a vector of
2671 three booleans or the predefined functions listed above, exactly like
2672 @code{break-visibility}. Both are properties of the Staff context,
2673 not the layout objects themselves, and so they are set using the
2674 @code{\set} command. Both are set by default to @code{all-visible}.
2675 These properties control only the visibility of key signatures and
2676 clefs resulting from explicit changes and do not affect key
2677 signatures and clefs at the beginning of lines;
2678 @code{break-visibility} must still be overridden in the appropriate
2679 object to remove these.
2681 @lilypond[quote,verbatim,relative=1,ragged-right]
2684 \set Staff.explicitKeySignatureVisibility = #all-invisible
2685 \override Staff.KeySignature #'break-visibility = #all-invisible
2692 @strong{@emph{Visibility of cautionary accidentals}}
2694 To remove the cautionary accidentals printed at an explicit key
2695 change, set the Staff context property @code{printKeyCancellation}
2698 @lilypond[quote,verbatim,relative=1,ragged-right]
2701 \set Staff.explicitKeySignatureVisibility = #all-invisible
2702 \set Staff.printKeyCancellation = ##f
2703 \override Staff.KeySignature #'break-visibility = #all-invisible
2710 With these overrides only the accidentals before the notes remain
2711 to indicate the change of key.
2713 @c TODO Add visibility of cautionary accidentals before notes
2715 @strong{@emph{Automatic bars}}
2717 @cindex automaticBars
2718 @cindex bar lines, suppressing
2720 As a special case, the printing of bar lines can also be turned off
2721 by setting the @code{automaticBars} property in the Score context.
2722 If set to @code{#f}, bar lines will not be printed automatically;
2723 they must be explicitly created with a @code{\bar} command. Unlike
2724 the @code{\cadenzaOn} predefined command, measures are still counted.
2725 Bar generation will resume according to that count if this property
2726 is later set to @code{#t}. When set to @code{#f}, line breaks can
2727 occur only at explicit @code{\bar} commands.
2731 @strong{@emph{Octavated clefs}}
2733 @cindex octavated clefs, visibility of
2734 @cindex visibility of octavated clefs
2735 @cindex clefs, visibility of octavation
2737 The small octavation symbol on octavated clefs is produced by the
2738 @code{OctavateEight} layout object. Its visibility is controlled
2739 independently from that of the @code{Clef} object, so it is
2740 necessary to apply any required @code{break-visibility} overrides
2741 to both the @code{Clef} and the @code{OctavateEight} layout objects
2742 to fully suppress such clef symbols at the start of each line.
2744 For explicit clef changes, the @code{explicitClefVisibility}
2745 property controls both the clef symbol and any octavation symbol
2751 @rlearning{Visibility and color of objects}
2755 @subsection Line styles
2757 Some performance indications, e.g., @i{rallentando} and
2758 @i{accelerando} and @i{trills} are written as text and are
2759 extended over many measures with lines, sometimes dotted or wavy.
2761 These all use the same routines as the glissando for drawing the
2762 texts and the lines, and tuning their behavior is therefore also
2763 done in the same way. It is done with a spanner, and the routine
2764 responsible for drawing the spanners is
2765 @code{ly:line-interface::print}. This routine determines the
2766 exact location of the two @i{span points} and draws a line
2767 between them, in the style requested.
2769 Here is an example showing the different line styles available,
2770 and how to tune them.
2772 @lilypond[relative=2,ragged-right,verbatim,fragment]
2774 \once \override Glissando #'style = #'dashed-line
2776 \override Glissando #'style = #'dotted-line
2778 \override Glissando #'style = #'zigzag
2780 \override Glissando #'style = #'trill
2784 The locations of the end-points of the spanner are computed
2785 on-the-fly for every graphic object, but it is possible to
2789 @lilypond[relative=2,ragged-right,verbatim,fragment]
2791 \once \override Glissando #'(bound-details right Y) = #-2
2795 The value for @code{Y} is set to @code{-2} for the right end
2796 point. The left side may be similarly adjusted by specifying
2797 @code{left} instead of @code{right}.
2799 If @code{Y} is not set, the value is computed from the vertical
2800 position of the left and right attachment points of the spanner.
2802 Other adjustments of spanners are possible, for details, see
2805 @node Rotating objects
2806 @subsection Rotating objects
2808 Both layout objects and elements of markup text can be rotated by
2809 any angle about any point, but the method of doing so differs.
2812 * Rotating layout objects::
2816 @node Rotating layout objects
2817 @unnumberedsubsubsec Rotating layout objects
2819 @cindex rotating objects
2820 @cindex objects, rotating
2822 All layout objects which support the @code{grob-interface} can be
2823 rotated by setting their @code{rotation} property. This takes a
2824 list of three items: the angle of rotation counter-clockwise,
2825 and the x and y coordinates of the point relative to the object's
2826 reference point about which the rotation is to be performed. The
2827 angle of rotation is specified in degrees and the coordinates in
2830 The angle of rotation and the coordinates of the rotation point must
2831 be determined by trial and error.
2833 @cindex hairpins, angled
2834 @cindex angled hairpins
2836 There are only a few situations where the rotation of layout
2837 objects is useful; the following example shows one situation where
2840 @lilypond[quote,verbatim,relative=1]
2842 \override Hairpin #'rotation = #'(20 -1 0)
2846 @node Rotating markup
2847 @unnumberedsubsubsec Rotating markup
2849 All markup text can be rotated to lie at any angle by prefixing it
2850 with the @code{\rotate} command. The command takes two arguments:
2851 the angle of rotation in degrees counter-clockwise and the text to
2852 be rotated. The extents of the text are not rotated: they take
2853 their values from the extremes of the x and y coordinates of the
2854 rotated text. In the following example the
2855 @code{outside-staff-priority} property for text is set to @code{#f}
2856 to disable the automatic collision avoidance, which would push some
2857 of the text too high.
2859 @lilypond[quote,verbatim,relative=1]
2860 \override TextScript #'outside-staff-priority = ##f
2861 g4^\markup { \rotate #30 "a G" }
2862 b^\markup { \rotate #30 "a B" }
2863 des^\markup { \rotate #30 "a D-Flat" }
2864 fis^\markup { \rotate #30 "an F-Sharp" }
2867 @node Advanced tweaks
2868 @section Advanced tweaks
2870 This section discusses various approaches to fine tuning the
2871 appearance of the printed score.
2874 * Aligning objects::
2875 * Vertical grouping of grobs::
2876 * Modifying stencils::
2877 * Modifying shapes::
2883 @rlearning{Tweaking output},
2884 @rlearning{Other sources of information}.
2887 @ref{Explaining the Internals Reference},
2888 @ref{Modifying properties},
2889 @ref{Interfaces for programmers}.
2892 @file{scm/@/define@/-grobs@/.scm}.
2895 @rlsr{Tweaks and overrides}.
2897 Internals Reference:
2898 @rinternals{All layout objects}.
2901 @node Aligning objects
2902 @subsection Aligning objects
2904 Graphical objects which support the @code{self-alignment-interface} and/or
2905 the @code{side-position-interface} can be
2906 aligned to a previously placed object in a variety of ways. For a list of these objects, see
2907 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
2909 All graphical objects have a reference point, a horizontal extent and a
2910 vertical extent. The horizontal extent is a pair of numbers
2911 giving the displacements from the reference point of the left and
2912 right edges, displacements to the left being negative. The
2913 vertical extent is a pair of numbers giving the displacement from
2914 the reference point to the bottom and top edges, displacements down
2917 An object's position on a staff is given by the values of the
2918 @code{X-offset} and @code{Y-offset} properties. The value of
2919 @code{X-offset} gives the displacement from the x coordinate of
2920 the reference point of the parent object, and the value of
2921 @code{Y-offset} gives the displacement from the center line of the
2922 staff. The values of @code{X-offset} and
2923 @code{Y-offset} may be set directly or may be set to be calculated
2924 by procedures in order to achieve alignment with the parent object
2927 @warning{Many objects have special positioning considerations which
2928 cause any setting of @code{X-offset} or @code{Y-offset} to be
2929 ignored or modified, even though the object supports the
2930 @code{self-alignment-interface}.}
2932 For example, an accidental can be repositioned
2933 vertically by setting @code{Y-offset} but any changes to
2934 @code{X-offset} have no effect.
2936 Rehearsal marks may be aligned with
2937 breakable objects such as bar lines, clef symbols, time signature
2938 symbols and key signatures. There are special properties to be
2939 found in the @code{break-aligned-interface} for positioning rehearsal
2940 marks on such objects.
2943 * Setting @code{X-offset} and @code{Y-offset} directly::
2944 * Using the @code{side-position-interface}::
2945 * Using the @code{self-alignment-interface}::
2946 * Using the @code{break-alignable-interface}::
2949 @node Setting @code{X-offset} and @code{Y-offset} directly
2950 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
2952 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
2953 properties of many objects. The following example shows three
2954 notes with the default fingering position and the positions with @code{X-offset}
2955 and @code{Y-offset} modified.
2957 @lilypond[verbatim,quote,relative=2]
2960 -\tweak #'X-offset #0
2961 -\tweak #'Y-offset #0
2964 -\tweak #'X-offset #-1
2965 -\tweak #'Y-offset #1
2971 @node Using the @code{side-position-interface}
2972 @unnumberedsubsubsec Using the @code{side-position-interface}
2974 An object which supports the @code{side-position-interface} can be
2975 placed next to its parent object so that
2976 the specified edges of the two objects touch. The object may be
2977 placed above, below, to the right or to the left of the parent.
2978 The parent cannot be specified; it is determined by the order of
2979 elements in the input stream. Most objects have the associated
2980 note head as their parent.
2982 The values of the @code{side-axis} and @code{direction} properties
2983 determine where the object is to be placed, as follows:
2985 @c TODO add an example of each to the table
2987 @multitable @columnfractions .3 .3 .3
2988 @headitem @code{side-axis} @tab @code{direction} @tab
2989 @headitem property @tab property @tab Placement
2991 @item @code{0} @tab @code{-1} @tab left
2992 @item @code{0} @tab @code{1} @tab right
2993 @item @code{1} @tab @code{-1} @tab below
2994 @item @code{1} @tab @code{1} @tab above
2998 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
2999 the procedure @code{ly:side-position-interface::x-aligned-side}.
3000 This procedure will return the correct value of @code{X-offset} to
3001 place the object to the left or right side of the parent according
3002 to value of @code{direction}.
3004 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3005 the procedure @code{ly:side-position-interface::y-aligned-side}.
3006 This procedure will return the correct value of @code{Y-offset} to
3007 place the object to the top or bottom of the parent according
3008 to value of @code{direction}.
3010 @c TODO Add examples
3012 @node Using the @code{self-alignment-interface}
3013 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3015 @emph{Self-aligning objects horizontally}
3017 The horizontal alignment of an object which supports the
3018 @code{self-alignment-interface} is controlled by the value of
3019 the @code{self-alignment-X} property, provided the object's
3020 @code{X-offset} property is set to
3021 @code{ly:self-alignment-interface::x-aligned-on-self}.
3022 @code{self-alignment-X} may be given any
3023 real value, in units of half the total X extent of the
3024 object. Negative values move the object to the right, positive
3025 to the left. A value of @code{0} centers the object on the
3026 reference point of its parent, a value of @code{-1} aligns the
3027 left edge of the object on the reference point of its parent,
3028 and a value of @code{1} aligns the right edge of the object on the
3029 reference point of its parent. The symbols @code{LEFT},
3030 @code{CENTER} and @code{RIGHT} may be used instead of the values
3031 @code{-1, 0, 1} respectively.
3033 Normally the @code{\override} command would be used to modify the
3034 value of @code{self-alignment-X}, but the @code{\tweak} command
3035 can be used to separately align several annotations on a single
3038 @lilypond[quote,verbatim,relative=1]
3040 -\tweak #'self-alignment-X #-1
3042 -\tweak #'self-alignment-X #0
3044 -\tweak #'self-alignment-X #RIGHT
3046 -\tweak #'self-alignment-X #-2.5
3047 ^"aligned further to the right"
3050 @emph{Self-aligning objects vertically}
3052 Objects may be aligned vertically in an analogous way to aligning
3053 them horizontally if the @code{Y-offset} property is set to
3054 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3055 other mechanisms are often involved in vertical alignment: the
3056 value of @code{Y-offset} is just one variable taken into account.
3057 This may make adjusting the value of some objects tricky.
3058 The units are just half the vertical extent of the object, which
3059 is usually quite small, so quite large numbers may be required.
3060 A value of @code{-1} aligns the lower edge of the object with
3061 the reference point of the parent object, a value of @code{0}
3062 aligns the center of the object with the reference point of the
3063 parent, and a value of @code{1} aligns the top edge of the object
3064 with the reference point of the parent. The symbols @code{DOWN},
3065 @code{CENTER}, @code{UP} may be substituted for @code{-1, 0, 1}
3068 @emph{Self-aligning objects in both directions}
3070 By setting both @code{X-offset} and @code{Y-offset}, an object may
3071 be aligned in both directions simultaneously.
3073 The following example shows how to adjust a fingering mark so
3074 that it nestles close to the note head.
3076 @lilypond[quote,verbatim,relative=2]
3078 -\tweak #'self-alignment-X #0.5 % move horizontally left
3079 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
3080 -\tweak #'self-alignment-Y #-1 % move vertically up
3085 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3087 @c Cannot document as they do not seem to operate consistently on all objects -td
3088 @c TODO investigate further
3090 The @code{aligned-on-parent} procedures are used in the same way
3091 as the @code{aligned-on-self} procedures, they difference being
3092 that they permit an object to be aligned with the @emph{edges} of
3093 the parent rather than the parent's reference point. The following
3094 example shows the difference:
3098 @lilypond[verbatim,quote]
3104 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3106 @c Cannot document as they do not seem to operate consistently on all objects -td
3107 @c TODO investigate further
3111 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3113 @node Using the @code{break-alignable-interface}
3114 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3116 @cindex align to objects
3117 @cindex break-align-symbols
3119 Rehearsal marks and bar numbers may be aligned with notation
3120 objects other than bar lines. These objects include @code{ambitus},
3121 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3122 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3123 @code{time-signature}.
3125 By default, rehearsal marks and bar numbers will be horizontally
3126 centered above the object:
3128 @lilypond[verbatim,quote,relative=1]
3130 % the RehearsalMark will be centered above the Clef
3131 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
3136 % the RehearsalMark will be centered above the TimeSignature
3137 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
3145 A list of possible target alignment objects may be specified. If
3146 some of the objects are invisible at that point due to the setting
3147 of @code{break-visibility} or the explicit visibility settings for
3148 keys and clefs, the rehearsal mark or bar number is aligned to the
3149 first object in the list which is visible. If no objects in the
3150 list are visible the object is aligned to the bar line. If the bar
3151 line is invisible the object is aligned to the place where the bar
3154 @lilypond[verbatim,quote,relative=1]
3156 % the RehearsalMark will be centered above the Key Signature
3157 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3162 % the RehearsalMark will be centered above the Clef
3163 \set Staff.explicitKeySignatureVisibility = #all-invisible
3164 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3171 The alignment of the rehearsal mark relative to the notation object
3172 can be changed, as shown in the following example. In a score with
3173 multiple staves, this setting should be done for all the staves.
3175 @lilypond[verbatim,quote,relative=1]
3176 % The RehearsalMark will be centered above the KeySignature
3177 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3183 % The RehearsalMark will be aligned with the left edge of the KeySignature
3184 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3188 % The RehearsalMark will be aligned with the right edge of the KeySignature
3189 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3195 The rehearsal mark can also be offset to the right or left of the left edge
3196 by an arbitrary amount. The units are staff-spaces:
3198 @lilypond[verbatim,quote,relative=1]
3199 % The RehearsalMark will be aligned with the left edge of the KeySignature
3200 % and then shifted right by 3.5 staff-spaces
3201 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3202 \once \override Score.KeySignature #'break-align-anchor = #3.5
3206 % The RehearsalMark will be aligned with the left edge of the KeySignature
3207 % and then shifted left by 2 staff-spaces
3208 \once \override Score.KeySignature #'break-align-anchor = #-2
3215 @node Vertical grouping of grobs
3216 @subsection Vertical grouping of grobs
3218 @c FIXME Expand this section
3220 The VerticalAlignment and VerticalAxisGroup grobs work together.
3221 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3222 etc. VerticalAlignment then vertically aligns the different grobs
3223 grouped together by VerticalAxisGroup. There is usually only one
3224 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3228 @node Modifying stencils
3229 @subsection Modifying stencils
3231 All layout objects have a @code{stencil} property which is part of
3232 the @code{grob-interface}. By default, this property is usually
3233 set to a function specific to the object that is tailor-made to
3234 render the symbol which represents it in the output. For example,
3235 the standard setting for the @code{stencil} property of the
3236 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3238 The standard symbol for any object can be replaced by modifying the
3239 @code{stencil} property to reference a different, specially-written,
3240 procedure. This requires a high level of knowledge of the internal
3241 workings of LilyPond, but there is an easier way which can often
3242 produce adequate results.
3244 This is to set the @code{stencil} property to the procedure which
3245 prints text -- @code{ly:text-interface::print} -- and to add a
3246 @code{text} property to the object which is set to contain the
3247 markup text which produces the required symbol. Due to the
3248 flexibility of markup, much can be achieved -- see in particular
3249 @ref{Graphic notation inside markup}.
3251 The following example demonstrates this by changing the note head
3252 symbol to a cross within a circle.
3254 @lilypond[verbatim,quote]
3256 \once \override NoteHead #'stencil = #ly:text-interface::print
3257 \once \override NoteHead #'text = \markup {
3259 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3260 \musicglyph #"noteheads.s2cross"
3268 Any of the glyphs in the feta Font can be supplied to the
3269 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3271 @c TODO Add inserting eps files or ref to later
3273 @c TODO Add inserting Postscript or ref to later
3278 @ref{Graphic notation inside markup},
3279 @ref{Formatting text},
3280 @ref{Text markup commands},
3281 @ref{The Feta font}.
3284 @node Modifying shapes
3285 @subsection Modifying shapes
3288 * Modifying ties and slurs::
3291 @node Modifying ties and slurs
3292 @unnumberedsubsubsec Modifying ties and slurs
3294 @cindex slurs, modifying
3295 @cindex ties, modifying
3296 @cindex Bézier curves
3297 @cindex Bézier control points
3299 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3300 curves. If the shape of the tie or slur which is calculated
3301 automatically is not optimum, the shape may be modified manually by
3302 explicitly specifying the four control points required to define
3303 a third-order Bézier curve.
3305 Third-order or cubic Bézier curves are defined by four control
3306 points. The first and fourth control points are precisely the
3307 starting and ending points of the curve. The intermediate two
3308 control points define the shape. Animations showing how the curve
3309 is drawn can be found on the web, but the following description
3310 may be helpful. The curve starts from the first control point
3311 heading directly towards the second, gradually bending over to
3312 head towards the third and continuing to bend over to head towards
3313 the fourth, arriving there travelling directly from the third
3314 control point. The curve is entirely contained in the
3315 quadrilateral defined by the four control points.
3317 Here is an example of a case where the tie is not optimum, and
3318 where @code{\tieDown} would not help.
3320 @lilypond[verbatim,quote,relative=1]
3324 { r4 <g c,> <g c,> <g c,> }
3328 One way of improving this tie is to manually modify its control
3331 The coordinates of the Bézier control points are specified in units
3332 of staff-spaces. The X@tie{}coordinate is relative to the reference
3333 point of the note to which the tie or slur is attached, and the
3334 Y@tie{}coordinate is relative to the staff center line. The
3335 coordinates are entered as a list of four pairs of decimal numbers
3336 (reals). One approach is to estimate the coordinates of the two
3337 end points, and then guess the two intermediate points. The optimum
3338 values are then found by trial and error.
3340 It is useful to remember that a symmetric curve requires symmetric
3341 control points, and that Bézier curves have the useful property that
3342 transformations of the curve such as translation, rotation and
3343 scaling can be achieved by applying the same transformation to the
3344 curve's control points.
3346 For the example above the following override gives a satisfactory
3347 tie. Note the placement -- it has to be immediately before the note
3348 to which the start of the tie (or slur) is attached.
3350 @lilypond[verbatim,quote,relative=1]
3354 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3358 { r4 <g c,> <g c,> <g c,>4 }
3364 It is not possible to modify shapes of ties or slurs by changing
3365 the @code{control-points} property if there are more than one at
3366 the same musical moment, not even by using the @code{\tweak}