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13 @node Changing defaults
14 @chapter Changing defaults
16 The purpose of LilyPond's design is to provide the finest quality
17 output by default. Nevertheless, it may happen that you need to
18 change this default layout. The layout is controlled through a large
19 number of @q{knobs and switches} collectively called @q{properties}.
20 A tutorial introduction to accessing and modifying these properties
21 can be found in the Learning Manual, see @rlearning{Tweaking output}.
22 This should be read first. This chapter covers similar ground, but
23 in a style more appropriate to a reference manual.
25 @cindex Internals Reference
27 The definitive description of the controls available for tuning can
28 be found in a separate document: @rinternalsnamed{Top,the Internals
29 Reference}. That manual lists all the variables, functions and
30 options available in LilyPond. It is written as a HTML document,
32 @c leave the @uref as one long line.
33 @uref{http://@/lilypond@/.org/@/doc/@/stable/@/Documentation/@/user/@/lilypond@/-internals/,on@/-line},
34 and is also included with the LilyPond documentation package.
36 Internally, LilyPond uses Scheme (a LISP dialect) to provide
37 infrastructure. Overriding layout decisions in effect accesses the
38 program internals, which requires Scheme input. Scheme elements are
39 introduced in a @file{.ly} file with the hash
40 mark@tie{}@code{#}.@footnote{@rextend{Scheme tutorial}, contains a
41 short tutorial on entering numbers, lists, strings, and symbols in
46 * Interpretation contexts::
47 * Explaining the Internals Reference::
48 * Modifying properties::
49 * Useful concepts and properties::
51 * Using music functions::
55 @node Interpretation contexts
56 @section Interpretation contexts
58 This section describes what contexts are, and how to modify them.
61 * Contexts explained::
63 * Keeping contexts alive::
64 * Modifying context plug-ins::
65 * Changing context default settings::
66 * Defining new contexts::
67 * Context layout order::
73 @rlearning{Contexts and engravers}.
76 @file{ly/engraver-init.ly},
77 @file{ly/performer-init.ly}.
80 @rlsr{Contexts and engravers}.
83 @rinternals{Contexts},
84 @rinternals{Engravers and Performers}.
87 @node Contexts explained
88 @subsection Contexts explained
91 @c TODO Rethink and rewrite
93 >> > > - list of contexts: my *danger unmaintainable*
94 >> > > alarm just went off. I'm
96 I knew it would... And leaving out some of them is perfectly fine
98 I do think that a list like this, with the main contexts and a
100 description of what they do (perhaps also with a note about what
102 behavior is associated with each of them, but this may be
104 should be there, and then we could simply list the remaining ones
106 further explanation and with links to the IR.
109 @c TODO Improve layout, order and consistency of wording -td
111 @c TODO Add introduction which explains contexts in generality -td
113 @c TODO Describe propagation of property values -td
115 Contexts are arranged hierarchically:
118 * Score - the master of all contexts::
119 * Top-level contexts - staff containers::
120 * Intermediate-level contexts - staves::
121 * Bottom-level contexts - voices::
124 @node Score - the master of all contexts
125 @unnumberedsubsubsec Score - the master of all contexts
127 This is the top level notation context. No other context can
128 contain a Score context. By default the Score context handles
129 the administration of time signatures and makes sure that items
130 such as clefs, time signatures, and key-signatures are aligned
133 A Score context is instantiated implicitly when a
134 @code{\score @{@dots{}@}} or @code{\layout @{@dots{}@}} block is
137 @node Top-level contexts - staff containers
138 @unnumberedsubsubsec Top-level contexts - staff containers
140 @strong{@emph{StaffGroup}}
142 Groups staves while adding a bracket on the left side, grouping
143 the staves together. The bar lines of the contained staves are
144 connected vertically. @code{StaffGroup} only consists of a collection
145 of staves, with a bracket in front and spanning bar lines.
147 @strong{@emph{ChoirStaff}}
149 Identical to @code{StaffGroup} except that the bar lines of the
150 contained staves are not connected vertically.
152 @strong{@emph{GrandStaff}}
154 A group of staves, with a brace on the left side, grouping the
155 staves together. The bar lines of the contained staves are
156 connected vertically.
158 @strong{@emph{PianoStaff}}
160 Just like @code{GrandStaff}, but with support for instrument names
161 to the left of each system.
163 @node Intermediate-level contexts - staves
164 @unnumberedsubsubsec Intermediate-level contexts - staves
166 @strong{@emph{Staff}}
168 Handles clefs, bar lines, keys, accidentals. It can contain
169 @code{Voice} contexts.
171 @strong{@emph{RhythmicStaff}}
173 Like @code{Staff} but for printing rhythms. Pitches are ignored;
174 the notes are printed on one line.
176 @strong{@emph{TabStaff}}
178 Context for generating tablature. By default lays the music
179 expression out as a guitar tablature, printed on six lines.
181 @strong{@emph{DrumStaff}}
183 Handles typesetting for percussion. Can contain @code{DrumVoice}
185 @strong{@emph{VaticanaStaff}}
187 Same as @code{Staff}, except that it is designed for typesetting
188 a piece in gregorian style.
190 @strong{@emph{MensuralStaff}}
192 Same as @code{Staff}, except that it is designed for typesetting
193 a piece in mensural style.
195 @node Bottom-level contexts - voices
196 @unnumberedsubsubsec Bottom-level contexts - voices
198 Voice-level contexts initialise certain properties and start
199 appropriate engravers. Being bottom-level contexts, they cannot
200 contain other contexts.
202 @strong{@emph{Voice}}
204 Corresponds to a voice on a staff. This context handles the
205 conversion of dynamic signs, stems, beams, super- and sub-scripts,
206 slurs, ties, and rests. You have to instantiate this explicitly
207 if you require multiple voices on the same staff.
209 @strong{@emph{VaticanaVoice}}
211 Same as @code{Voice}, except that it is designed for typesetting
212 a piece in gregorian style.
214 @strong{@emph{MensuralVoice}}
216 Same as @code{Voice}, with modifications for typesetting a piece in
219 @strong{@emph{Lyrics}}
221 Corresponds to a voice with lyrics. Handles the printing of a
222 single line of lyrics.
224 @strong{@emph{DrumVoice}}
226 The voice context used in a percussion staff.
228 @strong{@emph{FiguredBass}}
230 The context in which @code{BassFigure} objects are created from
231 input entered in @code{\figuremode} mode.
233 @strong{@emph{TabVoice}}
235 The voice context used within a @code{TabStaff} context. Usually
236 left to be created implicitly.
238 @strong{@emph{CueVoice}}
240 A voice context used to render notes of a reduced size, intended
241 primarily for adding cue notes to a staff, see @ref{Formatting
242 cue notes}. Usually left to be created implicitly.
244 @strong{@emph{ChordNames}}
246 Typesets chord names.
251 Then the following, which I don't know what to do with:
253 * GregorianTranscriptionVoice
254 * GregorianTranscriptionStaff
257 Engraves fretboards from chords. Not easy... Not
259 There is now some documentation on FretBoards in the NR, under
260 instrument-specific notation -- cds.
265 Hard coded entry point for LilyPond. Cannot be tuned.
267 Silently discards all musical information given to this
272 @node Creating contexts
273 @subsection Creating contexts
275 @c TODO more complete descriptions rather than learning style
277 For scores with only one voice and one staff, contexts are
278 created automatically. For more complex scores, it is necessary to
279 create them by hand. There are three commands that do this.
284 The easiest command is @code{\new}, and it also the quickest to type.
285 It is prepended to a music expression, for example
289 @cindex Context, creating
292 \new @var{type} @var{music expression}
296 where @var{type} is a context name (like @code{Staff} or
297 @code{Voice}). This command creates a new context, and starts
298 interpreting the @var{music expression} with that.
300 A practical application of @code{\new} is a score with many
301 staves. Each part that should be on its own staff, is preceded with
304 @lilypond[quote,verbatim,relative=2,ragged-right]
311 The @code{\new} command may also give a name to the context,
314 \new @var{type} = @var{id} @var{music}
316 However, this user specified name is only used if there is no other
317 context already earlier with the same name.
323 Like @code{\new}, the @code{\context} command also directs a music
324 expression to a context object, but gives the context an explicit name. The
328 \context @var{type} = @var{id} @var{music}
331 This form will search for an existing context of type @var{type}
332 called @var{id}. If that context does not exist yet, a new
333 context with the specified name is created. This is useful if
334 the context is referred to later on. For example, when
335 setting lyrics the melody is in a named context
338 \context Voice = "@b{tenor}" @var{music}
342 so the texts can be properly aligned to its notes,
345 \new Lyrics \lyricsto "@b{tenor}" @var{lyrics}
350 Another possible use of named contexts is funneling two different
351 music expressions into one context. In the following example,
352 articulations and notes are entered separately,
356 arts = @{ s4-. s4-> @}
359 They are combined by sending both to the same @code{Voice} context,
363 \new Staff \context Voice = "A" \music
364 \context Voice = "A" \arts
367 @lilypond[quote,ragged-right]
371 \new Staff \context Voice = "A" \music
372 \context Voice = "A" \arts
376 With this mechanism, it is possible to define an Urtext (original
377 edition), with the option to put several distinct articulations on the
380 @cindex creating contexts
383 The third command for creating contexts is
385 \context @var{type} @var{music}
390 This is similar to @code{\context} with @code{= @var{id}}, but matches
391 any context of type @var{type}, regardless of its given name.
393 This variant is used with music expressions that can be interpreted at
394 several levels. For example, the @code{\applyOutput} command (see
395 @rextend{Running a function on all layout objects}). Without an explicit
396 @code{\context}, it is usually applied to @code{Voice}
399 \applyOutput #'@var{context} #@var{function} % apply to Voice
402 To have it interpreted at the @code{Score} or @code{Staff} level use
406 \applyOutput #'Score #@var{function}
407 \applyOutput #'Staff #@var{function}
412 @node Keeping contexts alive
413 @subsection Keeping contexts alive
415 @cindex contexts, keeping alive
416 @cindex contexts, lifetime
418 Contexts are usually terminated at the first musical moment in
419 which they have nothing to do. So @code{Voice} contexts die as
420 soon as they contain no events; @code{Staff} contexts die as soon
421 as all the @code{Voice} contexts within them contain no events; etc.
422 This can cause difficulties if earlier contexts which have died
423 have to be referenced, for example, when changing staves with
424 @code{\change} commands, associating lyrics with a voice with
425 @code{\lyricsto} commands, or when adding further musical events to
428 There is an exception to this general rule: just one of the
429 @code{Voice} contexts in a @code{Staff} context or in a
430 @code{<<...>>} construct will always persist to the end of the
431 enclosing @code{Staff} context or @code{<<...>>} construct, even
432 though there may be periods when it has nothing to do. The context
433 to persist in this way will be the first one encountered in the
434 first enclosed @code{@{...@}} construct, ignoring any in enclosed
435 @code{<<...>>} constructs.
437 Any context can be kept alive by ensuring it has something to do at
438 every musical moment. @code{Staff} contexts are kept alive by
439 ensuring one of their voices is kept alive. One way of doing this
440 is to add spacer rests to a voice in parallel with the real music.
441 These need to be added to every @code{Voice} context which needs to
442 be kept alive. If several voices are to be used sporadically it is
443 safest to keep them all alive rather than attempting to rely on the
444 exceptions mentioned above.
446 In the following example, both voice A and voice B are kept alive
447 in this way for the duration of the piece:
449 @lilypond[quote,verbatim]
450 musicA = \relative c'' { d4 d d d }
451 musicB = \relative c'' { g4 g g g }
454 \new Voice = "A" { s1*5 } % Keep Voice "A" alive for 5 bars
455 \new Voice = "B" { s1*5 } % Keep Voice "B" alive for 5 bars
460 \context Voice = "A" {
464 \context Voice = "B" {
468 \context Voice = "A" { \musicA }
469 \context Voice = "B" { \musicB }
470 \context Voice = "A" { \musicA }
481 @cindex lyrics, aligning with sporadic melody
483 The following example shows how a sporadic melody line with lyrics
484 might be written using this approach. In a real situation the
485 melody and accompaniment would consist of several different
488 @lilypond[quote,verbatim]
489 melody = \relative c'' { a4 a a a }
490 accompaniment = \relative c' { d4 d d d }
491 words = \lyricmode { These words fol -- low the mel -- o -- dy }
494 \new Staff = "music" {
496 \new Voice = "melody" {
498 s1*4 % Keep Voice "melody" alive for 4 bars
501 \new Voice = "accompaniment" {
506 \context Voice = "melody" { \melody }
507 \context Voice = "accompaniment" { \accompaniment }
509 \context Voice = "accompaniment" { \accompaniment }
511 \context Voice = "melody" { \melody }
512 \context Voice = "accompaniment" { \accompaniment }
517 \new Lyrics \with { alignAboveContext = #"music" }
518 \lyricsto "melody" { \words }
523 An alternative way, which may be better in many circumstances, is
524 to keep the melody line alive by simply including spacer notes to
525 line it up correctly with the accompaniment:
527 @lilypond[quote,verbatim]
528 melody = \relative c'' {
534 accompaniment = \relative c' {
540 words = \lyricmode { These words fol -- low the mel -- o -- dy }
544 \new Staff = "music" {
546 \new Voice = "melody" {
550 \new Voice = "accompaniment" {
556 \new Lyrics \with { alignAboveContext = #"music" }
557 \lyricsto "melody" { \words }
563 @node Modifying context plug-ins
564 @subsection Modifying context plug-ins
566 @c TODO Should this be Modifying engravers or Modifying contexts?
568 Notation contexts (like @code{Score} and @code{Staff}) not only
570 they also contain plug-ins called @q{engravers} that create notation
571 elements. For example, the @code{Voice} context contains a
572 @code{Note_heads_engraver} and the @code{Staff} context contains a
573 @code{Key_signature_engraver}.
575 For a full a description of each plug-in, see
577 @rinternals{Engravers and Performers}.
580 Internals Reference @expansion{} Translation @expansion{} Engravers.
582 Every context described in
584 @rinternals{Contexts}
587 Internals Reference @expansion{} Translation @expansion{} Context.
589 lists the engravers used for that context.
592 It can be useful to shuffle around these plug-ins. This is done by
593 starting a new context with @code{\new} or @code{\context}, and
599 \new @var{context} \with @{
612 where the @dots{} should be the name of an engraver. Here is a simple
613 example which removes @code{Time_signature_engraver} and
614 @code{Clef_engraver} from a @code{Staff} context,
616 @lilypond[quote,relative=1,verbatim]
622 \remove "Time_signature_engraver"
623 \remove "Clef_engraver"
630 In the second staff there are no time signature or clef symbols. This
631 is a rather crude method of making objects disappear since it will affect
632 the entire staff. This method also influences the spacing, which may or
633 may not be desirable. More sophisticated methods of blanking objects
634 are shown in @rlearning{Visibility and color of objects}.
636 The next example shows a practical application. Bar lines and time
637 signatures are normally synchronized across the score. This is done
638 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
639 This plug-in keeps an administration of time signature, location
640 within the measure, etc. By moving these engraver from @code{Score} to
641 @code{Staff} context, we can have a score where each staff has its own
644 @cindex polymetric scores
645 @cindex Time signatures, multiple
647 @lilypond[quote,verbatim]
651 \consists "Timing_translator"
652 \consists "Default_bar_line_engraver"
658 \consists "Timing_translator"
659 \consists "Default_bar_line_engraver"
668 \remove "Timing_translator"
669 \remove "Default_bar_line_engraver"
677 Usually the order in which the engravers are specified
678 does not matter, but in a few special cases the order
679 is important, for example where one engraver writes
680 a property and another reads it, or where one engraver
681 creates a grob and another must process it. The order in
682 which the engravers are specified is the order in which
683 they are called to carry out their processing.
685 The following orderings are important: the
686 @code{Bar_engraver} must normally be first, and
687 the @code{New_fingering_engraver} must come before
688 the @code{Script_column_engraver}. There may be others
689 with ordering dependencies.
691 @node Changing context default settings
692 @subsection Changing context default settings
694 The context settings which are to be used by default in
695 @code{Score}, @code{Staff} and @code{Voice} contexts may be specified
696 in a @code{\layout} block, as illustrated in the following example.
697 The @code{\layout} block should be placed within the @code{\score}
698 block to which it is to apply, but outside any music.
700 Note that the @code{\set} command itself and the context must be
701 omitted when the context default values are specified in this way:
703 @lilypond[quote,verbatim]
706 a4^"Really small, thicker stems, no time signature" a a a
713 \override Stem #'thickness = #4.0
714 \remove "Time_signature_engraver"
720 In this example, the @code{\Staff} command specifies that the
721 subsequent specifications are to be applied to all staves within
724 Modifications can be made to the @code{Score} context or all
725 @code{Voice} contexts in a similar way.
729 It is not possible to collect context changes in a variable and apply
730 them to a @code{\context} definition by referring to that variable.
732 The @code{\Staff \RemoveEmptyStaves} will overwrite your current
733 @code{\Staff} settings. If you wish to change the defaults for a
734 staff which uses @code{\Staff \RemoveEmptyStaves}, you must do so
735 after calling @code{\Staff \RemoveEmptyStaves}, ie
740 \Staff \RemoveEmptyStaves
742 \override Stem #'thickness = #4.0
747 @c TODO: add \with in here.
751 @node Defining new contexts
752 @subsection Defining new contexts
754 @cindex contexts, defining new
755 @cindex engravers, including in contexts
770 Specific contexts, like @code{Staff} and @code{Voice}, are made of
771 simple building blocks. It is possible to create new types of
772 contexts with different combinations of engraver plug-ins.
774 The next example shows how to build a different type of
775 @code{Voice} context from scratch. It will be similar to
776 @code{Voice}, but only prints centered slash note heads. It can be used
777 to indicate improvisation in jazz pieces,
779 @lilypond[quote,ragged-right]
782 \type "Engraver_group"
783 \consists "Note_heads_engraver"
784 \consists "Rhythmic_column_engraver"
785 \consists "Text_engraver"
786 \consists Pitch_squash_engraver
787 squashedPosition = #0
788 \override NoteHead #'style = #'slash
789 \override Stem #'transparent = ##t
790 \override Flag #'transparent = ##t
794 \accepts "ImproVoice"
798 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
799 c4 c^"undress" c_"while playing :)" c }
805 These settings are defined within a @code{\context} block inside a
806 @code{\layout} block,
816 In the following discussion, the example input shown should go in place
817 of the @dots{} in the previous fragment.
819 First it is necessary to define a name for the new context:
825 Since it is similar to the @code{Voice}, we want commands that work
826 on (existing) @code{Voice}s to remain working. This is achieved by
827 giving the new context an alias @code{Voice},
833 The context will print notes and instructive texts, so we need to add
834 the engravers which provide this functionality,
837 \consists Note_heads_engraver
838 \consists Text_engraver
841 but we only need this on the center line,
844 \consists Pitch_squash_engraver
845 squashedPosition = #0
848 The @rinternals{Pitch_squash_engraver} modifies note heads (created
849 by @rinternals{Note_heads_engraver}) and sets their vertical
850 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
853 The notes look like a slash, and have no stem,
856 \override NoteHead #'style = #'slash
857 \override Stem #'transparent = ##t
858 \override Flag #'transparent = ##t
859 \override Flag #'transparent = ##t
862 All these plug-ins have to cooperate, and this is achieved with a
863 special plug-in, which must be marked with the keyword @code{\type}.
864 This should always be @code{Engraver_group}.
867 \type "Engraver_group"
875 \type "Engraver_group"
876 \consists "Note_heads_engraver"
877 \consists "Text_engraver"
878 \consists Pitch_squash_engraver
879 squashedPosition = #0
880 \override NoteHead #'style = #'slash
881 \override Stem #'transparent = ##t
882 \override Flag #'transparent = ##t
883 \override Flag #'transparent = ##t
889 Contexts form hierarchies. We want to hang the @code{ImproVoice}
890 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
891 modify the @code{Staff} definition with the @code{\accepts}
902 The opposite of @code{\accepts} is @code{\denies},
903 which is sometimes needed when reusing existing context definitions.
905 Putting both into a @code{\layout} block, like
915 \accepts "ImproVoice"
920 Then the output at the start of this subsection can be entered as
928 c c_"while playing :)"
935 @node Context layout order
936 @subsection Context layout order
938 @cindex contexts, layout order
942 Contexts are normally positioned in a system from top to bottom
943 in the order in which they are encountered in the input file. When
944 contexts are nested, the outer context will include inner nested
945 contexts as specified in the input file, provided the inner contexts
946 are included in the outer context's @qq{accepts} list. Nested
947 contexts which are not included in the outer context's @qq{accepts}
948 list will be repositioned below the outer context rather than nested
951 The @qq{accepts} list of a context can be changed with the
952 @code{\accepts} and @code{\denies} commands. @code{\accepts} adds a
953 context to the @qq{accepts} list and @code{\denies} removes a context
954 from the list. For example, it would not normally be desirable for
955 chord names to be nested within a @code{Staff} context, so the
956 @code{ChordNames} context is not included by default in the @qq{accepts}
957 list of the @code{Staff} context, but if this were to be required it can
960 @lilypond[verbatim,quote]
964 \chords { d1:m7 b1:min7.5- }
969 @lilypond[verbatim,quote]
973 \chords { d1:m7 b1:min7.5- }
978 \accepts "ChordNames"
984 @code{\denies} is mainly used when a new context is being based on
985 another, but the required nesting differs. For example, the
986 @code{VaticanaStaff} context is based on the @code{Staff} context, but
987 with the @code{VaticanaVoice} context substituted for the @code{Voice}
988 context in the @qq{accepts} list.
990 Note that a context will be silently created implicitly if a command
991 is encountered when there is no suitable context available to
992 contain it. This can give rise to unexpected new staves or scores.
996 @rprogram{An extra staff appears}.
999 @file{ly/engraver-init.ly}.
1003 @node Explaining the Internals Reference
1004 @section Explaining the Internals Reference
1008 * Navigating the program reference::
1009 * Layout interfaces::
1010 * Determining the grob property::
1011 * Naming conventions::
1014 @node Navigating the program reference
1015 @subsection Navigating the program reference
1017 @c TODO remove this (it's in the LM)
1018 @c Replace with more factual directions
1020 Suppose we want to move the fingering indication in the fragment
1023 @lilypond[quote,relative=2,verbatim]
1029 If you visit the documentation on fingering instructions (in
1030 @ref{Fingering instructions}), you will notice:
1035 Internals Reference: @rinternals{Fingering}.
1040 @c outdated info; probably will delete.
1042 This fragment points to two parts of the program reference: a page
1043 on @code{FingeringEvent} and one on @code{Fingering}.
1045 The page on @code{FingeringEvent} describes the properties of the music
1046 expression for the input @w{@code{-2}}. The page contains many links
1047 forward. For example, it says
1050 Accepted by: @rinternals{Fingering_engraver},
1054 That link brings us to the documentation for the Engraver, the
1058 This engraver creates the following layout objects: @rinternals{Fingering}.
1061 In other words, once the @code{FingeringEvent}s are interpreted, the
1062 @code{Fingering_engraver} plug-in will process them.
1066 @c I can't figure out what this is supposed to mean. -gp
1068 The @code{Fingering_engraver} is also listed to create
1069 @rinternals{Fingering} objects,
1071 @c old info? it doesn't make any sense to me with our current docs.
1073 second bit of information listed under @b{See also} in the Notation
1078 The programmer's reference is available as an HTML document. It is
1079 highly recommended that you read it in HTML form, either online or
1080 by downloading the HTML documentation. This section will be much more
1081 difficult to understand if you are using the
1085 Follow the link to @rinternals{Fingering}. At the top of the
1089 Fingering objects are created by: @rinternals{Fingering_engraver} and
1090 @rinternals{New_fingering_engraver}.
1093 By following related links inside the program reference, we can follow the
1094 flow of information within the program:
1098 @item @rinternals{Fingering}:
1099 @rinternals{Fingering} objects are created by:
1100 @rinternals{Fingering_engraver}
1102 @item @rinternals{Fingering_engraver}:
1103 Music types accepted: @rinternals{fingering-event}
1105 @item @rinternals{fingering-event}:
1106 Music event type @code{fingering-event} is in Music expressions named
1107 @rinternals{FingeringEvent}
1110 This path goes against the flow of information in the program: it
1111 starts from the output, and ends at the input event. You could
1112 also start at an input event, and read with the flow of
1113 information, eventually ending up at the output object(s).
1115 The program reference can also be browsed like a normal document. It
1116 contains chapters on
1118 @rinternals{Music definitions},
1121 @code{Music definitions}
1123 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1124 chapter lists all the definitions used and all properties that may be
1128 @node Layout interfaces
1129 @subsection Layout interfaces
1131 @cindex interface, layout
1132 @cindex layout interface
1135 The HTML page that we found in the previous section describes the
1136 layout object called @rinternals{Fingering}. Such an object is a
1137 symbol within the score. It has properties that store numbers (like
1138 thicknesses and directions), but also pointers to related objects. A
1139 layout object is also called a @emph{Grob}, which is short for Graphical
1140 Object. For more details about Grobs, see @rinternals{grob-interface}.
1142 The page for @code{Fingering} lists the definitions for the
1143 @code{Fingering} object. For example, the page says
1146 @code{padding} (dimension, in staff space):
1152 which means that the number will be kept at a distance of at least 0.5
1156 Each layout object may have several functions as a notational or
1157 typographical element. For example, the Fingering object
1158 has the following aspects
1162 Its size is independent of the horizontal spacing, unlike slurs or beams.
1165 It is a piece of text. Granted, it is usually a very short text.
1168 That piece of text is typeset with a font, unlike slurs or beams.
1171 Horizontally, the center of the symbol should be aligned to the
1172 center of the note head.
1175 Vertically, the symbol is placed next to the note and the staff.
1178 The vertical position is also coordinated with other superscript
1179 and subscript symbols.
1182 Each of these aspects is captured in so-called @emph{interface}s,
1183 which are listed on the @rinternals{Fingering} page at the bottom
1186 This object supports the following interfaces:
1187 @rinternals{item-interface},
1188 @rinternals{self-alignment-interface},
1189 @rinternals{side-position-interface}, @rinternals{text-interface},
1190 @rinternals{text-script-interface}, @rinternals{font-interface},
1191 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1194 Clicking any of the links will take you to the page of the respective
1195 object interface. Each interface has a number of properties. Some of
1196 them are not user-serviceable (@q{Internal properties}), but others
1199 We have been talking of @emph{the} @code{Fingering} object, but actually it
1200 does not amount to much. The initialization file (see
1201 @rlearning{Other sources of information})
1202 @file{scm/define-grobs.scm} shows the soul of the @q{object},
1207 (avoid-slur . around)
1208 (slur-padding . 0.2)
1209 (staff-padding . 0.5)
1210 (self-alignment-X . 0)
1211 (self-alignment-Y . 0)
1212 (script-priority . 100)
1213 (stencil . ,ly:text-interface::print)
1214 (direction . ,ly:script-interface::calc-direction)
1215 (font-encoding . fetaText)
1216 (font-size . -5) ; don't overlap when next to heads.
1217 (meta . ((class . Item)
1218 (interfaces . (finger-interface
1220 text-script-interface
1222 side-position-interface
1223 self-alignment-interface
1224 item-interface))))))
1228 As you can see, the @code{Fingering} object is nothing more than a
1229 bunch of variable settings, and the webpage in the Internals Reference
1230 is directly generated from this definition.
1233 @node Determining the grob property
1234 @subsection Determining the grob property
1236 @c TODO remove this (it's in the LM)
1237 @c Replace with more factual directions
1239 Recall that we wanted to change the position of the @b{2} in
1241 @lilypond[quote,relative=2,verbatim]
1247 Since the @b{2} is vertically positioned next to its note, we have to
1248 meddle with the interface associated with this positioning. This is
1249 done using @code{side-position-interface}. The page for this interface
1253 @code{side-position-interface}
1255 Position a victim object (this one) next to other objects (the
1256 support). The property @code{direction} signifies where to put the
1257 victim object relative to the support (left or right, up or down?)
1262 Below this description, the variable @code{padding} is described as
1267 (dimension, in staff space)
1269 Add this much extra space between objects that are next to each other.
1273 By increasing the value of @code{padding}, we can move the
1274 fingering away from the note head. The following command inserts
1275 3 staff spaces of white
1276 between the note and the fingering:
1278 \once \override Voice.Fingering #'padding = #3
1281 Inserting this command before the Fingering object is created,
1282 i.e., before @code{c2}, yields the following result:
1284 @lilypond[quote,relative=2,verbatim]
1285 \once \override Voice.Fingering #'padding = #3
1292 In this case, the context for this tweak is @code{Voice}. This
1293 fact can also be deduced from the program reference, for the page for
1294 the @rinternals{Fingering_engraver} plug-in says
1297 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1301 @node Naming conventions
1302 @subsection Naming conventions
1304 Another thing that is needed, is an overview of the various naming
1308 @item scheme functions: lowercase-with-hyphens (incl. one-word
1310 @item scheme functions: ly:plus-scheme-style
1311 @item music events, music classes and music properties:
1313 @item Grob interfaces: scheme-style
1314 @item backend properties: scheme-style (but X and Y!)
1315 @item contexts (and MusicExpressions and grobs): Capitalized or
1317 @item context properties: lowercaseFollowedByCamelCase
1319 Capitalized_followed_by_lowercase_and_with_underscores
1322 Questions to be answered:
1324 @item Which of these are conventions and which are rules?
1325 @item Which are rules of the underlying language, and which are
1329 @node Modifying properties
1330 @section Modifying properties
1332 @c TODO change the menu and subsection node names to use
1333 @c backslash once the new macro to handle the refs
1334 @c is available. Need to find and change all refs at
1335 @c the same time. -td
1338 * Overview of modifying properties::
1340 * The override command::
1341 * The tweak command::
1342 * set versus override::
1343 * Modifying alists::
1347 @node Overview of modifying properties
1348 @subsection Overview of modifying properties
1350 Each context is responsible for creating certain types of graphical
1351 objects. The settings used for printing these objects are also stored by
1352 context. By changing these settings, the appearance of objects can be
1355 There are two different kinds of properties stored in contexts:
1356 context properties and grob properties. Context properties are
1357 properties that apply to the context as a whole and control
1358 how the context itself is displayed. In contrast, grob properties
1359 apply to specific grob types that will be displayed in the context.
1361 The @code{\set} and @code{\unset} commands are used to change values
1362 for context properties. The @code{\override} and @code{\revert}
1363 commands are used to change values for grob properties.
1366 The syntax for this is
1369 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1372 Here @var{name} is the name of a graphical object, like
1373 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1374 variable of the formatting system (@q{grob property} or @q{layout
1375 property}). The latter is a symbol, so it must be quoted. The
1376 subsection @ref{Modifying properties}, explains what to fill in
1377 for @var{name}, @var{property}, and @var{value}. Here we only
1378 discuss the functionality of this command.
1383 \override Staff.Stem #'thickness = #4.0
1387 makes stems thicker (the default is 1.3, with staff line thickness as a
1388 unit). Since the command specifies @code{Staff} as context, it only
1389 applies to the current staff. Other staves will keep their normal
1390 appearance. Here we see the command in action:
1392 @lilypond[quote,verbatim,relative=2]
1394 \override Staff.Stem #'thickness = #4.0
1400 The @code{\override} command changes the definition of the @code{Stem}
1401 within the current @code{Staff}. After the command is interpreted
1402 all stems are thickened.
1404 Analogous to @code{\set}, the @var{context} argument may be left out,
1405 causing the default context @code{Voice} to be used. Adding
1406 @code{\once} applies the change during one timestep only.
1408 @lilypond[quote,verbatim,relative=2]
1410 \once \override Stem #'thickness = #4.0
1415 The @code{\override} must be done before the object is
1416 started. Therefore, when altering @emph{Spanner} objects such as slurs
1417 or beams, the @code{\override} command must be executed at the moment
1418 when the object is created. In this example,
1420 @lilypond[quote,verbatim,relative=2]
1421 \override Slur #'thickness = #3.0
1423 \override Beam #'beam-thickness = #0.6
1428 the slur is fatter but the beam is not. This is because the command for
1429 @code{Beam} comes after the Beam is started, so it has no effect.
1431 Analogous to @code{\unset}, the @code{\revert} command for a context
1432 undoes an @code{\override} command; like with @code{\unset}, it only
1433 affects settings that were made in the same context. In other words, the
1434 @code{\revert} in the next example does not do anything.
1437 \override Voice.Stem #'thickness = #4.0
1438 \revert Staff.Stem #'thickness
1441 Some tweakable options are called @q{subproperties} and reside inside
1442 properties. To tweak those, use commands of the form
1444 @c leave this as a long long
1446 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1453 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1460 @rinternals{Backend},
1461 @rinternals{All layout objects},
1462 @rinternals{OverrideProperty},
1463 @rinternals{RevertProperty},
1464 @rinternals{PropertySet}.
1469 The back-end is not very strict in type-checking object properties.
1470 Cyclic references in Scheme values for properties can cause hangs
1471 or crashes, or both.
1475 @node The set command
1476 @subsection The @code{@bs{}set} command
1480 @cindex changing properties
1482 Each context has a set of @emph{properties}, variables contained
1483 in that context. Context properties are changed with the @code{\set}
1484 command, which has the following syntax:
1487 \set @var{context}.@var{property} = #@var{value}
1490 @var{value} is a Scheme object, which is why it must be preceded by
1491 the @code{#}@tie{}character.
1493 Contexts properties are usually named in
1494 @code{studlyCaps}. They mostly control the translation from
1495 music to notation, e.g. @code{localKeySignature} (for determining
1496 whether to print accidentals), or @code{measurePosition} (for
1497 determining when to print a bar line). Context properties can
1498 change value over time while interpreting a piece of music;
1499 @code{measurePosition} is an obvious example of
1500 this. Context properties are modified with @code{\set}.
1502 For example, multimeasure rests will be combined into a single bar
1503 if the context property @code{skipBars} is set to @code{#t}:
1505 @lilypond[quote,verbatim,relative=2]
1507 \set Score.skipBars = ##t
1511 If the @var{context} argument is left out, then the property will be
1512 set in the current bottom context (typically @code{ChordNames},
1513 @code{Voice}, @code{TabVoice}, or @code{Lyrics}).
1515 @lilypond[quote,verbatim,relative=2]
1516 \set Score.autoBeaming = ##f
1520 \set autoBeaming = ##t
1528 The change is applied @q{on-the-fly}, during the music, so that the
1529 setting only affects the second group of eighth notes.
1531 Note that the bottom-most context does not always contain the property
1532 that you wish to change -- for example, attempting to set the
1533 @code{skipBars} property of the default bottom context, in this case
1534 @code{Voice}, will have no effect, because skipBars is a property of
1535 the @code{Score} context.
1537 @lilypond[quote,verbatim,relative=2]
1543 Contexts are hierarchical, so if an enclosing context was specified, for
1544 example @code{Staff}, then the change would also apply to all
1545 @code{Voice}s in the current staff.
1549 The @code{\unset} command:
1552 \unset @var{context}.@var{property}
1556 is used to remove the definition of @var{property} from
1557 @var{context}. This command removes
1558 the definition only if it is set in @var{context}.
1559 Properties that have been set in enclosing contexts will
1560 not be altered by an unset in an enclosed context:
1562 @lilypond[quote,verbatim,relative=2]
1563 \set Score.autoBeaming = ##t
1568 \unset Score.autoBeaming
1576 Like @code{\set}, the @var{context} argument does not have to be
1577 specified for a bottom context, so the two statements
1580 \set Voice.autoBeaming = ##t
1581 \set autoBeaming = ##t
1585 are equivalent if the current bottom context is @code{Voice}.
1589 Preceding a @code{\set} command by @code{\once} makes the
1590 setting apply to only a single time-step:
1592 @lilypond[quote,verbatim,relative=2]
1594 \once \set fontSize = #4.7
1599 A full description of all available context properties is in the
1600 internals reference, see
1602 @rinternals{Tunable context properties}.
1605 Translation @expansion{} Tunable context properties.
1610 Internals Reference:
1612 @rinternals{Tunable context properties}.
1615 @cindex grob properties
1616 @cindex properties, grob
1620 @node The override command
1621 @subsection The @code{\override} command
1623 There is a special type of context property: the grob
1624 description. Grob descriptions are named in @code{StudlyCaps}
1625 (starting with capital letters). They contain the
1626 @q{default settings} for a particular kind of grob as an
1627 association list. See @file{scm/define-grobs.scm}
1628 to see the settings for each grob description. Grob descriptions
1629 are modified with @code{\override}.
1631 @code{\override} is actually a shorthand;
1634 \override @var{context}.@var{GrobName} #'@var{property} = #@var{value}
1638 is more or less equivalent to
1640 @c leave this long line -gp
1642 \set @var{context}.@var{GrobName} =
1643 #(cons (cons '@var{property} @var{value})
1644 <previous value of @var{context}.@var{GrobName}>)
1647 The value of @code{context}.@code{GrobName} (the alist) is used to initialize
1648 the properties of individual grobs. Grobs have
1649 properties, named in Scheme style, with
1650 @code{dashed-words}. The values of grob properties change
1651 during the formatting process: formatting basically amounts
1652 to computing properties using callback functions.
1654 For example, we can increase the thickness of a note stem by
1655 overriding the @code{thickness} property of the @code{Stem}
1658 @lilypond[quote,verbatim,relative=2]
1660 \override Voice.Stem #'thickness = #3.0
1664 If no context is specified in an @code{\override}, the bottom
1667 @lilypond[quote,verbatim,relative=2]
1668 { \override Staff.Stem #'thickness = #3.0
1672 \override Stem #'thickness = #0.5
1682 @cindex reverting overrides
1683 @cindex overrides, reverting
1685 The effects of @code{\override} can be undone by @code{\revert}:
1687 @lilypond[quote,verbatim,relative=2]
1689 \override Voice.Stem #'thickness = #3.0
1691 \revert Voice.Stem #'thickness
1695 The effects of @code{\override} and @code{\revert} apply to all
1696 grobs in the affected context from the current time forward:
1698 @lilypond[quote,verbatim,relative=2]
1703 \override Staff.Stem #'thickness = #3.0
1707 \revert Staff.Stem #'thickness
1715 @cindex overriding for only one moment
1717 @code{\once} can be used with @code{\override}
1718 to affect only the current time step:
1720 @lilypond[quote,verbatim,relative=2]
1724 \override Stem #'thickness = #3.0
1728 \once \override Stem #'thickness = #3.0
1737 Commands which change output generally look like
1740 \override Voice.Stem #'thickness = #3.0
1744 To construct this tweak we must determine these bits of information:
1747 @item the context: here @code{Voice}.
1748 @item the layout object: here @code{Stem}.
1749 @item the layout property: here @code{thickness}.
1750 @item a sensible value: here @code{3.0}.
1753 Some tweakable options are called @q{subproperties} and reside inside
1754 properties. To tweak those, use commands in the form
1757 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1760 @cindex internal documentation
1761 @cindex finding graphical objects
1762 @cindex graphical object descriptions
1765 @cindex internal documentation
1767 For many properties, regardless of the data type of the property, setting the
1768 property to false (@code{#f}) will result in turning it off, causing
1769 LilyPond to ignore that property entirely. This is particularly useful for
1770 turning off grob properties which may otherwise be causing problems.
1772 We demonstrate how to glean this information from the notation manual
1773 and the program reference.
1778 Internals Reference:
1779 @rinternals{Backend}
1781 @node The tweak command
1782 @subsection The @code{\tweak} command
1787 Changing grob properties
1788 with @code{\override} causes the changes to apply to all of the
1789 given grobs in the context at the moment the change applies.
1790 Sometimes, however, it is desirable to have changes apply to just
1791 one grob, rather than to all grobs in the affected context. This is
1792 accomplished with the @code{\tweak} command, which has the following
1796 \tweak #'@code{grob-property} #@code{value}
1799 The @code{\tweak} command applies to the object that immediately
1800 follows @code{value} in the music stream.
1803 In some cases, it is possible to take a short-cut for tuning
1804 graphical objects. For objects that are created directly from
1805 an item in the input file, you can use the @code{\tweak} command.
1808 @lilypond[relative=2,verbatim,quote]
1813 \tweak #'duration-log #1
1816 -\tweak #'padding #8
1822 But the main use of the @code{\tweak} command is to modify just
1823 one of a number of notation elements which start at the same musical
1824 moment, like the notes of a chord, or tuplet brackets which start
1827 The @code{\tweak} command sets a property in the following object
1828 directly, without requiring the grob name or context to be
1829 specified. For this to work, it is necessary for the @code{\tweak}
1830 command to remain immediately adjacent to the object to which it is
1831 to apply after the input file has been converted to a music stream.
1832 This is often not the case, as many additional elements are inserted
1833 into the music stream implicitly. For example, when a note which is
1834 not part of a chord is processed, LilyPond implicitly inserts a
1835 @code{ChordEvent} event before the note, so separating the tweak
1836 from the note. However, if chord symbols are placed round the
1837 tweak and the note, the @code{\tweak} command comes after the
1838 @code{ChordEvent} in the music stream, so remaining adjacent to the
1839 note, and able to modify it.
1843 @lilypond[relative=2,verbatim,quote]
1844 <\tweak #'color #red c>4
1850 @lilypond[relative=2,verbatim,quote]
1851 \tweak #'color #red c4
1856 For an introduction to the syntax and uses of the tweak command
1857 see @rlearning{Tweaking methods}.
1859 When several similar items are placed at the same musical moment,
1860 the @code{\override} command cannot be used to modify just one of
1861 them -- this is where the @code{\tweak} command must be used.
1862 Items which may appear more than once at the same musical moment
1863 include the following:
1865 @c TODO expand to include any further uses of \tweak
1867 @item note heads of notes inside a chord
1868 @item articulation signs on a single note
1869 @item ties between notes in a chord
1870 @item tuplet brackets starting at the same time
1873 @c TODO add examples of these
1875 @cindex chord, modifying one note in
1877 In this example, the color of one note head and the type of another
1878 note head are modified within a single chord:
1880 @lilypond[relative=2,verbatim,quote]
1885 \tweak #'duration-log #1
1890 @code{\tweak} can be used to modify slurs:
1892 @lilypond[verbatim,quote,relative=1]
1893 c-\tweak #'thickness #5 ( d e f)
1897 For the @code{\tweak} command to work, it must
1898 remain immediately adjacent to the object to which it is
1899 to apply after the input file has been converted to a music stream.
1900 At times, LilyPond may insert additional items into the music stream
1901 during the parsing process. For example, when a note that is not
1902 explicitly part of a chord will be placed in a chord by LilyPond,
1903 so notes to be modified with @code{\tweak} must be placed inside
1906 @lilypond[relative=2,verbatim,quote]
1907 \tweak #'color #red c4
1908 <\tweak #'color #red c>4
1911 The @code{\tweak} command cannot be used to modify any item
1912 that does not appear explicitly in the input file. In particular
1913 it cannot be used to modify stems,
1914 beams or accidentals directly, since these are generated later by
1915 note heads, rather than by music elements in the input stream.
1916 Nor can @code{\tweak} be used to modify clefs or time
1917 signatures, since these become separated from any preceding
1918 @code{\tweak} command in the input stream by the automatic
1919 insertion of extra elements required to specify the context.
1921 Several @code{\tweak} commands may be placed before a
1922 notational element -- all affect it:
1924 @lilypond[verbatim,quote,relative=1]
1926 -\tweak #'style #'dashed-line
1927 -\tweak #'dash-fraction #0.2
1928 -\tweak #'thickness #3
1929 -\tweak #'color #red
1934 The music stream which is generated from a section of an input file,
1935 including any automatically inserted elements, may be examined,
1936 see @rextend{Displaying music expressions}. This may be helpful in
1937 determining what may be modified by a @code{\tweak} command, or
1938 in determining how to adjust the input to make a @code{\tweak}
1944 @rlearning{Tweaking methods}.
1947 @rextend{Displaying music expressions}.
1952 @cindex tweaks in a variable
1953 The @code{\tweak} command cannot be used inside a variable.
1955 @cindex tweaks in lyrics
1956 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1958 @cindex tweaking control points
1959 @cindex control points, tweaking
1961 The @code{\tweak} command will apply to only the first of several
1962 generated ties in a chord.
1964 @node set versus override
1965 @subsection @code{\set} vs. @code{\override}
1967 @c TODO -- This section is probably unnecessary now.
1970 We have seen two methods of changing properties: @code{\set} and
1971 @code{\override}. There are actually two different kinds of
1974 @code{fontSize} is a special property: it is equivalent to
1975 entering @code{\override ... #'font-size} for all pertinent
1976 objects. Since this is a common change, the special
1977 property (modified with @code{\set}) was created.
1982 @node Modifying alists
1983 @subsection Modifying alists
1985 Some user-configurable properties are internally represented as
1986 @emph{alists} (association lists), which store pairs of
1987 @emph{keys} and @emph{values}. The structure of an alist is:
1990 '((@var{key1} . @var{value1})
1991 (@var{key2} . @var{value2})
1992 (@var{key3} . @var{value3})
1996 If an alist is a grob property or @code{\paper} variable, its keys
1997 can be modified individually without affecting other keys.
1999 For example, to reduce the space between adjacent staves in a
2000 staff-group, use the @code{staff-staff-spacing} property of the
2001 @code{StaffGrouper} grob. The property is an alist with four
2002 keys: @code{basic-distance}, @code{minimum-distance},
2003 @code{padding}, and @code{stretchability}. The standard settings
2004 for this property are listed in the @qq{Backend} section of the
2005 Internals Reference (see @rinternals{StaffGrouper}):
2008 '((basic-distance . 9)
2009 (minimum-distance . 7)
2011 (stretchability . 5))
2014 One way to bring the staves closer together is by reducing the
2015 value of the @code{basic-distance} key (@code{9}) to match the
2016 value of @code{minimum-distance} (@code{7}). To modify a single
2017 key individually, use a @emph{nested declaration}:
2019 @lilypond[quote,verbatim]
2020 % default space between staves
2022 \new Staff { \clef treble c''1 }
2023 \new Staff { \clef bass c1 }
2026 % reduced space between staves
2027 \new PianoStaff \with {
2028 % this is the nested declaration
2029 \override StaffGrouper #'staff-staff-spacing #'basic-distance = #7
2031 \new Staff { \clef treble c''1 }
2032 \new Staff { \clef bass c1 }
2036 Using a nested declaration will update the specified key (such as
2037 @code{basic-distance} in the above example) without altering any
2038 other keys already set for the same property.
2040 Now suppose we want the staves to be as close as possible without
2041 overlapping. The simplest way to do this is to set all four alist
2042 keys to zero. However, it is not necessary to enter four nested
2043 declarations, one for each key. Instead, the property can be
2044 completely re-defined with one declaration, as an alist:
2046 @lilypond[quote,verbatim]
2047 \new PianoStaff \with {
2048 \override StaffGrouper #'staff-staff-spacing =
2049 #'((basic-distance . 0)
2050 (minimum-distance . 0)
2052 (stretchability . 0))
2054 \new Staff { \clef treble c''1 }
2055 \new Staff { \clef bass c1 }
2059 Note that any keys not explicitly listed in the alist definition
2060 will be reset to their @emph{default-when-unset} values. In the
2061 case of @code{staff-staff-spacing}, any unset key-values would be
2062 reset to zero (except @code{stretchability}, which takes the value
2063 of @code{basic-distance} when unset). Thus the following two
2064 declarations are equivalent:
2067 \override StaffGrouper #'staff-staff-spacing =
2068 #'((basic-distance . 7))
2070 \override StaffGrouper #'staff-staff-spacing =
2071 #'((basic-distance . 7)
2072 (minimum-distance . 0)
2074 (stretchability . 7))
2077 One (possibly unintended) consequence of this is the removal of
2078 any standard settings that are set in an initialization file and
2079 loaded each time an input file is compiled. In the above example,
2080 the standard settings for @code{padding} and
2081 @code{minimum-distance} (defined in @file{scm/define-grobs.scm})
2082 are reset to their default-when-unset values (zero for both keys).
2083 Defining a property or variable as an alist (of any size) will
2084 always reset all unset key-values to their default-when-unset
2085 values. Unless this is the intended result, it is safer to update
2086 key-values individually with a nested declaration.
2088 @warning{Nested declarations will not work for context property
2089 alists (such as @code{beamExceptions}, @code{keySignature},
2090 @code{timeSignatureSettings}, etc.). These properties can only be
2091 modified by completely re-defining them as alists.}
2094 @node Useful concepts and properties
2095 @section Useful concepts and properties
2100 * Direction and placement::
2101 * Distances and measurements::
2102 * Staff symbol properties::
2104 * Visibility of objects::
2106 * Rotating objects::
2110 @subsection Input modes
2112 The way in which the notation contained within an input file is
2113 interpreted is determined by the current input mode.
2117 This is activated with the @code{\chordmode} command, and causes
2118 input to be interpreted with the syntax of chord notation, see
2119 @ref{Chord notation}. Chords are rendered as notes on a staff.
2121 Chord mode is also activated with the @code{\chords} command.
2122 This also creates a new @code{ChordNames} context and
2123 causes the following input to be interpreted with the syntax of
2124 chord notation and rendered as chord names in the @code{ChordNames}
2125 context, see @ref{Printing chord names}.
2129 This is activated with the @code{\drummode} command, and causes
2130 input to be interpreted with the syntax of drum notation, see
2131 @ref{Basic percussion notation}.
2133 Drum mode is also activated with the @code{\drums} command.
2134 This also creates a new @code{DrumStaff} context and causes the
2135 following input to be interpreted with the syntax of drum notation
2136 and rendered as drum symbols on a drum staff, see @ref{Basic
2137 percussion notation}.
2139 @strong{Figure mode}
2141 This is activated with the @code{\figuremode} command, and causes
2142 input to be interpreted with the syntax of figured bass, see
2143 @ref{Entering figured bass}.
2145 Figure mode is also activated with the @code{\figures} command.
2146 This also creates a new @code{FiguredBass} context and causes the
2147 following input to be interpreted with the figured bass syntax
2148 and rendered as figured bass symbols in the @code{FiguredBass}
2149 context, see @ref{Introduction to figured bass}.
2151 @strong{Fret and tab modes}
2153 There are no special input modes for entering fret and tab symbols.
2155 To create tab diagrams, enter notes or chords in note mode and
2156 render them in a @code{TabStaff} context, see
2157 @ref{Default tablatures}.
2159 To create fret diagrams above a staff, you have two choices.
2160 You can either use the @code{FretBoards} context (see
2161 @ref{Automatic fret diagrams} or you can enter them as a markup
2162 above the notes using the @code{\fret-diagram} command (see
2163 @ref{Fret diagram markups}).
2165 @strong{Lyrics mode}
2167 This is activated with the @code{\lyricmode} command, and causes
2168 input to be interpreted as lyric syllables with optional durations
2169 and associated lyric modifiers, see @ref{Vocal music}.
2171 Lyric mode is also activated with the @code{\addlyrics} command.
2172 This also creates a new @code{Lyrics} context and an implicit
2173 @code{\lyricsto} command which associates the following lyrics
2174 with the preceding music.
2176 @strong{Markup mode}
2178 This is activated with the @code{\markup} command, and causes
2179 input to be interpreted with the syntax of markup, see
2180 @ref{Text markup commands}.
2182 @c silly work-around for texinfo broken-ness
2183 @c (@strong{Note...} causes a spurious cross-reference in Info)
2186 This is the default mode or it may be activated with the
2187 @code{\notemode} command. Input is interpreted as pitches,
2188 durations, markup, etc and typeset as musical notation on a staff.
2190 It is not normally necessary to specify note mode explicitly, but
2191 it may be useful to do so in certain situations, for example if you
2192 are in lyric mode, chord mode or any other mode and want to insert
2193 something that only can be done with note mode syntax.
2195 For example, to indicate dynamic markings for the verses of a
2196 choral pieces it is necessary to enter note mode to interpret
2199 @lilypond[verbatim,relative=2,quote]
2202 \notemode{\set stanza = \markup{ \dynamic f 1. } }
2206 \notemode{\set stanza = \markup{ \dynamic p 2. } }
2213 @node Direction and placement
2214 @subsection Direction and placement
2216 In typesetting music the direction and placement of many items is
2217 a matter of choice. For example, the stems of notes can
2218 be directed up or down; lyrics, dynamics, and other expressive
2219 marks may be placed above or below the staff; text may be aligned
2220 left, right or center; etc. Most of these choices may be left to
2221 be determined automatically by LilyPond, but in some cases it may
2222 be desirable to force a particular direction or placement.
2224 @strong{Articulation direction indicators}
2226 By default some directions are always up or always down (e.g.
2227 dynamics or fermata), while other things can alternate between
2228 up or down based on the stem direction (like slurs or accents).
2230 @c TODO Add table showing these
2232 The default action may be overridden by prefixing the articulation
2233 by a @emph{direction indicator}. Three direction indicators are
2234 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
2235 and @code{-} (meaning @qq{use default direction}). The direction
2236 indicator can usually be omitted, in which case @code{-} is assumed,
2237 but a direction indicator is @strong{always} required before
2240 @item @code{\tweak} commands
2241 @item @code{\markup} commands
2242 @item @code{\tag} commands
2243 @item string markups, e.g. -"string"
2244 @item fingering instructions, e.g. @w{@code{-1}}
2245 @item articulation shortcuts, e.g. @w{@code{-.}}, @w{@code{->}}, @w{@code{--}}
2248 Direction indicators affect only the next note:
2250 @lilypond[verbatim,quote,relative=2]
2257 @strong{The direction property}
2259 The position or direction of many layout objects is controlled
2260 by the @code{direction} property.
2262 The value of the @code{direction} property may be
2263 set to @code{1}, meaning @qq{up} or @qq{above}, or to @w{@code{-1}},
2264 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
2265 @code{DOWN} may be used instead of @code{1} and @w{@code{-1}}
2266 respectively. The default direction may be specified by setting
2267 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
2268 in many cases predefined commands
2269 exist to specify the direction. These are all of the form
2272 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
2275 where @code{xxxNeutral} means @qq{use the default direction}.
2276 See @rlearning{Within-staff objects}.
2278 In a few cases, arpeggio being the only common example, the value
2279 of the @code{direction} property specifies whether the object
2280 is to be placed to the right or left of the parent object. In
2281 this case @w{@code{-1}} or @code{LEFT} means @qq{to the left} and
2282 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
2283 or @code{CENTER} means @qq{use the default} direction, as before.
2286 These all have side-axis set to #X
2287 AmbitusAccidental - direction has no effect
2289 StanzaNumber - not tried
2290 TrillPitchAccidental - not tried
2291 TrillPitchGroup - not tried
2294 These indications affect all notes until they are cancelled.
2296 @lilypond[verbatim,quote,relative=2]
2306 @node Distances and measurements
2307 @subsection Distances and measurements
2309 @cindex distances, absolute
2310 @cindex distances, scaled
2317 Distances in LilyPond are of two types: absolute and scaled.
2319 Absolute distances are used for specifying margins, indents, and
2320 other page layout details, and are by default specified in
2321 millimeters. Distances may be specified in other units by
2322 following the quantity by @code{\mm}, @code{\cm},
2323 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27 of
2324 an inch). Page layout distances can also be specified in scalable
2325 units (see the following paragraph) by appending
2326 @code{\staff-space} to the quantity. Page layout is described in
2327 detail in @ref{Page layout}.
2329 Scaled distances are always specified in units of the staff-space
2330 or, rarely, the half staff-space. The staff-space is the distance
2331 between two adjacent staff lines. The default value can be changed
2332 globally by setting the global staff size, or it can be overridden
2333 locally by changing the @code{staff-space} property of
2334 @code{StaffSymbol}. Scaled distances automatically scale with any
2335 change to the either the global staff size or the
2336 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2337 automatically only with changes to the global staff size.
2338 The global staff size thus enables the overall size of a rendered
2339 score to be easily varied. For the methods of setting the global
2340 staff size see @ref{Setting the staff size}.
2344 If just a section of a score needs to be rendered to a different
2345 scale, for example an ossia section or a footnote, the global staff
2346 size cannot simply be changed as this would affect the entire score.
2347 In such cases the change in size is made by overriding both the
2348 @code{staff-space} property of @code{StaffSymbol} and the size of
2349 the fonts. A Scheme function, @code{magstep}, is available to
2350 convert from a font size change to the equivalent change in
2351 @code{staff-space}. For an explanation and an example of its use,
2352 see @rlearning{Length and thickness of objects}.
2357 @rlearning{Length and thickness of objects}.
2361 @ref{Setting the staff size}.
2364 @node Staff symbol properties
2365 @subsection Staff symbol properties
2367 @cindex adjusting staff symbol
2368 @cindex drawing staff symbol
2369 @cindex staff symbol, setting of
2371 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2372 @c Need to think of uses for these properties. Eg 'line-positions
2373 @c is used in a snippet to thicken centre line.
2374 @c If retained, add @ref to here in 1.6.2 -td
2376 The vertical position of staff lines and the number of staff lines
2377 can be defined at the same time. As the following example shows,
2378 note positions are not influenced by the staff line positions.
2380 @warning{The @code{'line-positions} property overrides the
2381 @code{'line-count} property. The number of staff lines is
2382 implicitly defined by the number of elements in the list of values
2383 for @code{'line-positions}.}
2385 @lilypond[verbatim,quote,relative=1]
2387 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
2392 The width of a staff can be modified. The units are staff
2393 spaces. The spacing of objects inside the staff is not affected by
2396 @lilypond[verbatim,quote,relative=1]
2398 \override StaffSymbol #'width = #23
2405 @subsection Spanners
2407 Many objects of musical notation extend over several notes or even
2408 several bars. Examples are slurs, beams, tuplet brackets, volta
2409 repeat brackets, crescendi, trills, and glissandi. Such objects
2410 are collectively called @qq{spanners}, and have special properties to control
2411 their appearance and behaviour. Some of these properties are common
2412 to all spanners; others are restricted to a sub-set of the spanners.
2414 All spanners support the @code{spanner-interface}. A few, essentially
2415 those that draw a straight line between the two objects, support in
2416 addition the @code{line-spanner-interface}.
2418 @unnumberedsubsubsec Using the @code{spanner-interface}
2420 This interface provides two properties that apply to several spanners.
2422 @strong{@i{The @code{minimum-length} property}}
2424 The minimum length of the spanner is specified by the
2425 @code{minimum-length} property. Increasing this usually has the
2426 necessary effect of increasing the spacing of the notes between the
2427 two end points. However, this override has no effect on
2428 many spanners, as their length is determined by other considerations.
2429 A few examples where it is effective are shown below.
2439 Works as long as callback is made:
2443 Works not at all for:
2452 @lilypond[verbatim,quote,relative=2]
2455 % increase the length of the tie
2456 -\tweak #'minimum-length #5
2460 @lilypond[verbatim,quote,relative=2]
2462 \compressFullBarRests
2464 % increase the length of the rest bar
2465 \once \override MultiMeasureRest #'minimum-length = #20
2470 @lilypond[verbatim,quote,relative=2]
2472 % increase the length of the hairpin
2473 \override Hairpin #'minimum-length = #20
2477 This override can also be used to increase the length of slurs and
2480 @lilypond[verbatim,quote,relative=2]
2483 -\tweak #'minimum-length #5
2488 -\tweak #'minimum-length #5
2492 For some layout objects, the @code{minimum-length} property becomes
2493 effective only if the @code{set-spacing-rods} procedure is called
2494 explicitly. To do this, the @code{springs-and-rods} property should
2495 be set to @code{ly:spanner::set-spacing-rods}. For example,
2496 the minimum length of a glissando has no effect unless the
2497 @code{springs-and-rods} property is set:
2499 @lilypond[verbatim,quote,relative=1]
2503 % not effective alone
2504 \once \override Glissando #'minimum-length = #20
2507 % effective only when both overrides are present
2508 \once \override Glissando #'minimum-length = #20
2509 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2513 The same is true of the @code{Beam} object:
2515 @lilypond[verbatim,quote,relative=1]
2516 % not effective alone
2517 \once \override Beam #'minimum-length = #20
2520 % effective only when both overrides are present
2521 \once \override Beam #'minimum-length = #20
2522 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2526 @strong{@i{The @code{to-barline} property}}
2528 The second useful property of the @code{spanner-interface} is
2529 @code{to-barline}. By default this is true, causing hairpins and
2530 other spanners which are terminated on the first note of a measure to
2531 end instead on the immediately preceding bar line. If set to false,
2532 the spanner will extend beyond the bar line and end on the note
2535 @lilypond[verbatim,quote,relative=2]
2536 a \< a a a a \! a a a \break
2537 \override Hairpin #'to-barline = ##f
2538 a \< a a a a \! a a a
2541 This property is not effective for all spanners. For example,
2542 setting it to @code{#t} has no effect on slurs or phrasing slurs
2543 or on other spanners for which terminating on the bar line would
2546 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2548 Objects which support the @code{line-spanner-interface} include
2551 @item @code{DynamicTextSpanner}
2552 @item @code{Glissando}
2553 @item @code{TextSpanner}
2554 @item @code{TrillSpanner}
2555 @item @code{VoiceFollower}
2558 The routine responsible for drawing the stencils for these spanners is
2559 @code{ly:line-interface::print}. This routine determines the
2560 exact location of the two end points and draws a line
2561 between them, in the style requested. The locations of the two
2562 end points of the spanner are computed on-the-fly, but it is
2563 possible to override their Y-coordinates. The
2564 properties which need to be specified are nested
2565 two levels down within the property hierarchy, but the syntax of
2566 the @code{\override} command is quite simple:
2568 @lilypond[relative=2,quote,verbatim]
2570 \once \override Glissando #'(bound-details left Y) = #3
2571 \once \override Glissando #'(bound-details right Y) = #-2
2575 The units for the @code{Y} property are @code{staff-space}s,
2576 with the center line of the staff being the zero point.
2577 For the glissando, this is the value for @code{Y} at the
2578 X-coordinate corresponding to the center point of each note head,
2579 if the line is imagined to be extended to there.
2581 If @code{Y} is not set, the value is computed from the vertical
2582 position of the corresponding attachment point of the spanner.
2584 In case of a line break, the values for the end points are
2585 specified by the @code{left-broken} and @code{right-broken}
2586 sub-lists of @code{bound-details}. For example:
2588 @lilypond[relative=2,ragged-right,verbatim,quote]
2589 \override Glissando #'breakable = ##t
2590 \override Glissando #'(bound-details right-broken Y) = #-3
2591 c1 \glissando \break
2596 A number of further properties of the @code{left} and
2597 @code{right} sub-lists of the @code{bound-details} property
2598 may be modified in the same way as @code{Y}:
2602 This sets the Y-coordinate of the end point, in @code{staff-space}s
2603 offset from the staff center line. By default, it is the center of
2604 the bound object, so a glissando points to the vertical center of
2607 For horizontal spanners, such as text spanners and trill spanners,
2608 it is hardcoded to 0.
2611 This determines where the line starts and ends in the X-direction,
2612 relative to the bound object. So, a value of @w{@code{-1}} (or
2613 @code{LEFT}) makes the line start/end at the left side of the note
2614 head it is attached to.
2617 This is the absolute X-coordinate of the end point. It is usually
2618 computed on the fly, and overriding it has little useful effect.
2621 Line spanners may have symbols at the beginning or end, which is
2622 contained in this sub-property. This is for internal use; it is
2623 recommended that @code{text} be used instead.
2626 This is a markup that is evaluated to yield the stencil. It is used
2627 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2629 @lilypond[quote,ragged-right,relative=2,verbatim]
2630 \override TextSpanner #'(bound-details left text)
2631 = \markup { \small \bold Slower }
2632 c2\startTextSpan b c a\stopTextSpan
2635 @item stencil-align-dir-y
2636 @item stencil-offset
2637 Without setting one of these, the stencil is simply put at the
2638 end-point, centered on the line, as defined by the @code{X} and
2639 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2640 or @code{stencil-offset} will move the symbol at the edge vertically
2641 relative to the end point of the line:
2643 @lilypond[relative=1,quote,verbatim]
2644 \override TextSpanner
2645 #'(bound-details left stencil-align-dir-y) = #-2
2646 \override TextSpanner
2647 #'(bound-details right stencil-align-dir-y) = #UP
2649 \override TextSpanner
2650 #'(bound-details left text) = #"ggg"
2651 \override TextSpanner
2652 #'(bound-details right text) = #"hhh"
2653 c4^\startTextSpan c c c \stopTextSpan
2656 Note that negative values move the text @emph{up}, contrary to the
2657 effect that might be expected, as a value of @w{@code{-1}} or
2658 @code{DOWN} means align the @emph{bottom} edge of the text with
2659 the spanner line. A value of @code{1} or @code{UP} aligns
2660 the top edge of the text with the spanner line.
2663 Setting this sub-property to @code{#t} produces an arrowhead at the
2667 This sub-property controls the space between the specified
2668 end point of the line and the actual end. Without padding, a
2669 glissando would start and end in the center of each note head.
2673 The music function @code{\endSpanners} terminates the spanner
2674 which starts on the immediately following note prematurely. It
2675 is terminated after exactly one note, or at the following bar line
2676 if @code{to-barline} is true and a bar line occurs before the next
2679 @lilypond[verbatim,quote,ragged-right,relative=2]
2681 c2 \startTextSpan c2 c2
2686 When using @code{\endSpanners} it is not necessary to close
2687 \startTextSpan with \stopTextSpan, nor is it necessary to close
2688 hairpins with @code{\!}.
2692 Internals Reference:
2693 @rinternals{TextSpanner},
2694 @rinternals{Glissando},
2695 @rinternals{VoiceFollower},
2696 @rinternals{TrillSpanner},
2697 @rinternals{line-spanner-interface}.
2700 @node Visibility of objects
2701 @subsection Visibility of objects
2703 @cindex objects, visibility of
2704 @cindex grobs, visibility of
2705 @cindex visibility of objects
2707 There are four main ways in which the visibility of layout objects
2708 can be controlled: their stencil can be removed, they can be made
2709 transparent, they can be colored white, or their
2710 @code{break-visibility} property can be overridden. The first
2711 three apply to all layout objects; the last to just a few -- the
2712 @emph{breakable} objects. The Learning Manual introduces these
2713 four techniques, see @rlearning{Visibility and color of objects}.
2715 There are also a few other techniques which are specific to
2716 certain layout objects. These are covered under Special
2720 * Removing the stencil::
2721 * Making objects transparent::
2722 * Painting objects white::
2723 * Using break-visibility::
2724 * Special considerations::
2728 @node Removing the stencil
2729 @unnumberedsubsubsec Removing the stencil
2731 @cindex stencil, removing
2733 Every layout object has a stencil property. By default this is set
2734 to the specific function which draws that object. If this property
2735 is overridden to @code{#f} no function will be called and the object
2736 will not be drawn. The default action can be recovered with
2739 @lilypond[quote,verbatim,relative=1]
2741 \override Score.BarLine #'stencil = ##f
2743 \revert Score.BarLine #'stencil
2747 @node Making objects transparent
2748 @unnumberedsubsubsec Making objects transparent
2750 @cindex transparent, making objects
2752 Every layout object has a transparent property which by default is
2753 set to @code{#f}. If set to @code{#t} the object still occupies
2754 space but is made invisible.
2756 @lilypond[quote,verbatim,relative=2]
2758 \once \override NoteHead #'transparent = ##t
2762 @node Painting objects white
2763 @unnumberedsubsubsec Painting objects white
2765 @cindex objects, coloring
2766 @cindex coloring objects
2768 @cindex printing order
2769 @cindex overwriting objects
2770 @cindex objects, overwriting
2771 @cindex grobs, overwriting
2773 Every layout object has a color property which by default is set
2774 to @code{black}. If this is overridden to @code{white} the object
2775 will be indistinguishable from the white background. However,
2776 if the object crosses other objects the color of the crossing
2777 points will be determined by the order in which they are drawn,
2778 and this may leave a ghostly image of the white object, as shown
2781 @lilypond[quote,verbatim,relative=2]
2782 \override Staff.Clef #'color = #white
2786 This may be avoided by changing the order of printing the objects.
2787 All layout objects have a @code{layer} property which should be set
2788 to an integer. Objects with the lowest value of @code{layer} are
2789 drawn first, then objects with progressively higher values are drawn,
2790 so objects with higher values overwrite objects with lower values.
2791 By default most objects are assigned a @code{layer} value of
2792 @code{1}, although a few objects, including @code{StaffSymbol} and
2793 @code{BarLine}, are assigned a value of @code{0}. The order of
2794 printing objects with the same value of @code{layer} is indeterminate.
2796 In the example above the white clef, with a default @code{layer}
2797 value of @code{1}, is drawn after the staff lines (default
2798 @code{layer} value @code{0}), so overwriting them. To change this,
2799 the @code{Clef} object must be given in a lower value of
2800 @code{layer}, say @w{@code{-1}}, so that it is drawn earlier:
2802 @lilypond[quote,verbatim,relative=2]
2803 \override Staff.Clef #'color = #white
2804 \override Staff.Clef #'layer = #-1
2808 @node Using break-visibility
2809 @unnumberedsubsubsec Using break-visibility
2811 @c TODO Add making other objects breakable
2813 @cindex break-visibility
2815 Most layout objects are printed only once, but some like
2816 bar lines, clefs, time signatures and key signatures, may need
2817 to be printed twice when a line break occurs -- once at the end
2818 of the line and again at the start of the next line. Such
2819 objects are called @emph{breakable}, and have a property, the
2820 @code{break-visibility} property to control their visibility
2821 at the three positions in which they may appear -- at the
2822 start of a line, within a line if they are changed, and at the
2823 end of a line if a change takes place there.
2825 For example, the time signature
2826 by default will be printed at the start of the first line, but
2827 nowhere else unless it changes, when it will be printed at the
2828 point at which the change occurs. If this change occurs at the
2829 end of a line the new time signature will be printed at the start
2830 of the next line and a cautionary time signature will be printed
2831 at the end of the previous line as well.
2833 This behaviour is controlled by the @code{break-visibility}
2834 property, which is explained in
2835 @c Leave this ref on a newline - formats incorrectly otherwise -td
2836 @rlearning{Visibility and color of objects}. This property takes
2837 a vector of three booleans which, in order, determine whether the
2838 object is printed at the end of, within the body of, or at the
2839 beginning of a line. Or to be more precise, before a line break,
2840 where there is no line break, or after a line break.
2842 Alternatively, these eight combinations may be specified
2843 by pre-defined functions, defined in @file{scm/output-lib.scm},
2844 where the last three columns indicate whether the layout objects
2845 will be visible in the positions shown at the head of the columns:
2847 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2848 @headitem Function @tab Vector @tab Before @tab At no @tab After
2849 @headitem form @tab form @tab break @tab break @tab break
2851 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2852 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2853 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2854 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2855 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2856 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2857 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2858 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2861 The default settings of @code{break-visibility} depend on the
2862 layout object. The following table shows all the layout objects
2863 of interest which are affected by @code{break-visibility} and the
2864 default setting of this property:
2866 @multitable @columnfractions .3 .3 .4
2868 @headitem Layout object @tab Usual context @tab Default setting
2870 @c omit Ambitus as it appears not to be affected by break-visibility -td
2871 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2872 @item @code{BarLine} @tab @code{Score} @tab calculated
2873 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2874 @c omit the following item until it can be explained -td
2875 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2876 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2877 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2878 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2879 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2880 @c omit KeyCancellation until it can be explained -td
2881 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2882 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2883 @c omit LeftEdge until it can be explained -td
2884 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2885 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2886 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2887 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2891 The example below shows the use of the vector form to control the
2892 visibility of bar lines:
2894 @lilypond[quote,verbatim,relative=1,ragged-right]
2897 % Remove bar line at the end of the current line
2898 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2904 Although all three components of the vector used to override
2905 @code{break-visibility} must be present, not all of them are
2906 effective with every layout object, and some combinations may
2907 even give errors. The following limitations apply:
2910 @item Bar lines cannot be printed at start of line.
2911 @item A bar number cannot be printed at the start of the first
2912 line unless it is set to be different from 1.
2913 @item Clef -- see below
2914 @item Double percent repeats are either all printed or all
2915 suppressed. Use begin-of line-invisible to print and
2916 all-invisible to suppress.
2917 @item Key signature -- see below
2918 @item OctavateEight -- see below
2921 @node Special considerations
2922 @unnumberedsubsubsec Special considerations
2924 @strong{@emph{Visibility following explicit changes}}
2926 @cindex key signature, visibility following explicit change
2927 @cindex explicitKeySignatureVisibility
2928 @cindex clef, visibility following explicit change
2929 @cindex explicitClefVisibility
2931 The @code{break-visibility} property controls the visibility of
2932 key signatures and changes of clef only at the start of lines,
2933 i.e. after a break. It has no effect on the visibility of the
2934 key signature or clef following an explicit key change or an
2935 explicit clef change within or at the end of a line. In the
2936 following example the key signature following the explicit change
2937 to B-flat major is still visible, even though @code{all-invisible}
2940 @lilypond[quote,verbatim,relative=1,ragged-right]
2943 % Try to remove all key signatures
2944 \override Staff.KeySignature #'break-visibility = #all-invisible
2952 The visibility of such explicit key signature and clef changes is
2953 controlled by the @code{explicitKeySignatureVisibility} and
2954 @code{explicitClefVisibility} properties. These are the equivalent
2955 of the @code{break-visibility} property and both take a vector of
2956 three booleans or the predefined functions listed above, exactly like
2957 @code{break-visibility}. Both are properties of the Staff context,
2958 not the layout objects themselves, and so they are set using the
2959 @code{\set} command. Both are set by default to @code{all-visible}.
2960 These properties control only the visibility of key signatures and
2961 clefs resulting from explicit changes and do not affect key
2962 signatures and clefs at the beginning of lines;
2963 @code{break-visibility} must still be overridden in the appropriate
2964 object to remove these.
2966 @lilypond[quote,verbatim,relative=1,ragged-right]
2969 \set Staff.explicitKeySignatureVisibility = #all-invisible
2970 \override Staff.KeySignature #'break-visibility = #all-invisible
2977 @strong{@emph{Visibility of cautionary accidentals}}
2979 To remove the cautionary accidentals printed at an explicit key
2980 change, set the Staff context property @code{printKeyCancellation}
2983 @lilypond[quote,verbatim,relative=1,ragged-right]
2986 \set Staff.explicitKeySignatureVisibility = #all-invisible
2987 \set Staff.printKeyCancellation = ##f
2988 \override Staff.KeySignature #'break-visibility = #all-invisible
2995 With these overrides only the accidentals before the notes remain
2996 to indicate the change of key.
2998 @c TODO Add visibility of cautionary accidentals before notes
3000 @strong{@emph{Automatic bars}}
3002 @cindex automaticBars
3003 @cindex bar lines, suppressing
3005 As a special case, the printing of bar lines can also be turned off
3006 by setting the @code{automaticBars} property in the Score context.
3007 If set to @code{#f}, bar lines will not be printed automatically;
3008 they must be explicitly created with a @code{\bar} command. Unlike
3009 the @code{\cadenzaOn} predefined command, measures are still counted.
3010 Bar generation will resume according to that count if this property
3011 is later set to @code{#t}. When set to @code{#f}, line breaks can
3012 occur only at explicit @code{\bar} commands.
3016 @strong{@emph{Octavated clefs}}
3018 @cindex octavated clefs, visibility of
3019 @cindex visibility of octavated clefs
3020 @cindex clefs, visibility of octavation
3022 The small octavation symbol on octavated clefs is produced by the
3023 @code{OctavateEight} layout object. Its visibility is automatically
3024 inherited from the @code{Clef} object, so it is not necessary to apply
3025 any required @code{break-visibility} overrides to the @code{OctavateEight}
3026 layout objects to suppress octavation symbols for invisible clefs.
3028 For explicit clef changes, the @code{explicitClefVisibility}
3029 property controls both the clef symbol and any octavation symbol
3035 @rlearning{Visibility and color of objects}
3039 @subsection Line styles
3041 Some performance indications, e.g., @i{rallentando} and
3042 @i{accelerando} and @i{trills} are written as text and are
3043 extended over many measures with lines, sometimes dotted or wavy.
3045 These all use the same routines as the glissando for drawing the
3046 texts and the lines, and tuning their behavior is therefore also
3047 done in the same way. It is done with a spanner, and the routine
3048 responsible for drawing the spanners is
3049 @code{ly:line-interface::print}. This routine determines the
3050 exact location of the two @i{span points} and draws a line
3051 between them, in the style requested.
3053 Here is an example showing the different line styles available,
3054 and how to tune them.
3056 @lilypond[relative=2,ragged-right,verbatim,quote]
3058 \once \override Glissando #'style = #'dashed-line
3060 \override Glissando #'style = #'dotted-line
3062 \override Glissando #'style = #'zigzag
3064 \override Glissando #'style = #'trill
3068 The locations of the end-points of the spanner are computed
3069 on-the-fly for every graphic object, but it is possible to
3073 @lilypond[relative=2,ragged-right,verbatim,quote]
3075 \once \override Glissando #'(bound-details right Y) = #-2
3079 The value for @code{Y} is set to @w{@code{-2}} for the right end
3080 point. The left side may be similarly adjusted by specifying
3081 @code{left} instead of @code{right}.
3083 If @code{Y} is not set, the value is computed from the vertical
3084 position of the left and right attachment points of the spanner.
3086 Other adjustments of spanners are possible, for details, see
3089 @node Rotating objects
3090 @subsection Rotating objects
3092 Both layout objects and elements of markup text can be rotated by
3093 any angle about any point, but the method of doing so differs.
3096 * Rotating layout objects::
3100 @node Rotating layout objects
3101 @unnumberedsubsubsec Rotating layout objects
3103 @cindex rotating objects
3104 @cindex objects, rotating
3106 All layout objects which support the @code{grob-interface} can be
3107 rotated by setting their @code{rotation} property. This takes a
3108 list of three items: the angle of rotation counter-clockwise,
3109 and the x and y coordinates of the point relative to the object's
3110 reference point about which the rotation is to be performed. The
3111 angle of rotation is specified in degrees and the coordinates in
3114 The angle of rotation and the coordinates of the rotation point must
3115 be determined by trial and error.
3117 @cindex hairpins, angled
3118 @cindex angled hairpins
3120 There are only a few situations where the rotation of layout
3121 objects is useful; the following example shows one situation where
3124 @lilypond[quote,verbatim,relative=1]
3126 \override Hairpin #'rotation = #'(20 -1 0)
3130 @node Rotating markup
3131 @unnumberedsubsubsec Rotating markup
3133 All markup text can be rotated to lie at any angle by prefixing it
3134 with the @code{\rotate} command. The command takes two arguments:
3135 the angle of rotation in degrees counter-clockwise and the text to
3136 be rotated. The extents of the text are not rotated: they take
3137 their values from the extremes of the x and y coordinates of the
3138 rotated text. In the following example the
3139 @code{outside-staff-priority} property for text is set to @code{#f}
3140 to disable the automatic collision avoidance, which would push some
3141 of the text too high.
3143 @lilypond[quote,verbatim,relative=1]
3144 \override TextScript #'outside-staff-priority = ##f
3145 g4^\markup { \rotate #30 "a G" }
3146 b^\markup { \rotate #30 "a B" }
3147 des^\markup { \rotate #30 "a D-Flat" }
3148 fis^\markup { \rotate #30 "an F-Sharp" }
3151 @node Advanced tweaks
3152 @section Advanced tweaks
3154 This section discusses various approaches to fine tuning the
3155 appearance of the printed score.
3158 * Aligning objects::
3159 * Vertical grouping of grobs::
3160 * Modifying stencils::
3161 * Modifying shapes::
3167 @rlearning{Tweaking output},
3168 @rlearning{Other sources of information}.
3171 @ref{Explaining the Internals Reference},
3172 @ref{Modifying properties}.
3175 @file{scm/define-grobs.scm}.
3178 @rlsr{Tweaks and overrides}.
3181 @rextend{Interfaces for programmers}.
3183 Internals Reference:
3184 @rinternals{All layout objects}.
3187 @node Aligning objects
3188 @subsection Aligning objects
3190 Graphical objects which support the @code{self-alignment-interface}
3191 and/or the @code{side-position-interface} can be aligned to a previously
3192 placed object in a variety of ways. For a list of these objects, see
3193 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
3195 All graphical objects have a reference point, a horizontal extent and a
3196 vertical extent. The horizontal extent is a pair of numbers
3197 giving the displacements from the reference point of the left and
3198 right edges, displacements to the left being negative. The vertical
3199 extent is a pair of numbers giving the displacement from the reference
3200 point to the bottom and top edges, displacements down being negative.
3202 An object's position on a staff is given by the values of the
3203 @code{X-offset} and @code{Y-offset} properties. The value of
3204 @code{X-offset} gives the displacement from the X coordinate of
3205 the reference point of the parent object, and the value of
3206 @code{Y-offset} gives the displacement from the center line of the
3207 staff. The values of @code{X-offset} and @code{Y-offset} may
3208 be set directly or may be set to be calculated by procedures in order
3209 to achieve alignment with the parent object.
3211 @warning{Many objects have special positioning considerations which
3212 cause any setting of @code{X-offset} or @code{Y-offset} to be
3213 ignored or modified, even though the object supports the
3214 @code{self-alignment-interface}. Overriding the @code{X-offset}
3215 or @code{Y-offset} properties to a fixed value causes the respective
3216 @code{self-alignment} property to be disregarded.}
3218 For example, an accidental can be repositioned vertically by setting
3219 @code{Y-offset} but any changes to @code{X-offset} have no effect.
3221 Rehearsal marks may be aligned with breakable objects such as bar
3222 lines, clef symbols, time signature symbols and key signatures. There
3223 are special properties to be found in the @code{break-aligned-interface}
3224 for positioning rehearsal marks on such objects.
3227 @ref{Using the break-alignable-interface},
3228 @rextend{Callback functions}.
3231 * Setting X-offset and Y-offset directly::
3232 * Using the side-position-interface::
3233 * Using the self-alignment-interface::
3234 * Using the break-alignable-interface::
3237 @node Setting X-offset and Y-offset directly
3238 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
3240 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
3241 properties of many objects. The following example shows three
3242 notes with the default fingering position and the positions with @code{X-offset}
3243 and @code{Y-offset} modified.
3245 @lilypond[verbatim,quote,relative=2]
3248 -\tweak #'X-offset #0
3249 -\tweak #'Y-offset #0
3252 -\tweak #'X-offset #-1
3253 -\tweak #'Y-offset #1
3259 @node Using the side-position-interface
3260 @unnumberedsubsubsec Using the @code{side-position-interface}
3262 An object which supports the @code{side-position-interface} can be
3263 placed next to its parent object so that
3264 the specified edges of the two objects touch. The object may be
3265 placed above, below, to the right or to the left of the parent.
3266 The parent cannot be specified; it is determined by the order of
3267 elements in the input stream. Most objects have the associated
3268 note head as their parent.
3270 The values of the @code{side-axis} and @code{direction} properties
3271 determine where the object is to be placed, as follows:
3273 @c TODO add an example of each to the table
3275 @multitable @columnfractions .3 .3 .3
3276 @headitem @code{side-axis} @tab @code{direction} @tab
3277 @headitem property @tab property @tab Placement
3279 @item @code{0} @tab @code{-1} @tab left
3280 @item @code{0} @tab @code{1} @tab right
3281 @item @code{1} @tab @code{-1} @tab below
3282 @item @code{1} @tab @code{1} @tab above
3286 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
3287 the procedure @code{ly:side-position-interface::x-aligned-side}.
3288 This procedure will return the correct value of @code{X-offset} to
3289 place the object to the left or right side of the parent according
3290 to value of @code{direction}.
3292 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3293 the procedure @code{ly:side-position-interface::y-aligned-side}.
3294 This procedure will return the correct value of @code{Y-offset} to
3295 place the object to the top or bottom of the parent according
3296 to value of @code{direction}.
3298 @c TODO Add examples
3300 @node Using the self-alignment-interface
3301 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3303 @emph{Self-aligning objects horizontally}
3305 The horizontal alignment of an object which supports the
3306 @code{self-alignment-interface} is controlled by the value of
3307 the @code{self-alignment-X} property, provided the object's
3308 @code{X-offset} property is set to
3309 @code{ly:self-alignment-interface::x-aligned-on-self}.
3310 @code{self-alignment-X} may be given any
3311 real value, in units of half the total X extent of the
3312 object. Negative values move the object to the right, positive
3313 to the left. A value of @code{0} centers the object on the
3314 reference point of its parent, a value of @w{@code{-1}} aligns the
3315 left edge of the object on the reference point of its parent,
3316 and a value of @code{1} aligns the right edge of the object on the
3317 reference point of its parent. The symbols @code{LEFT},
3318 @code{CENTER}, and @code{RIGHT} may be used instead of the values
3319 @w{@code{-1}}, @code{0}, and @code{1}, respectively.
3321 Normally the @code{\override} command would be used to modify the
3322 value of @code{self-alignment-X}, but the @code{\tweak} command
3323 can be used to separately align several annotations on a single
3326 @lilypond[quote,verbatim,relative=1]
3328 -\tweak #'self-alignment-X #-1
3330 -\tweak #'self-alignment-X #0
3332 -\tweak #'self-alignment-X #RIGHT
3334 -\tweak #'self-alignment-X #-2.5
3335 ^"aligned further to the right"
3338 @emph{Self-aligning objects vertically}
3340 Objects may be aligned vertically in an analogous way to aligning
3341 them horizontally if the @code{Y-offset} property is set to
3342 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3343 other mechanisms are often involved in vertical alignment: the
3344 value of @code{Y-offset} is just one variable taken into account.
3345 This may make adjusting the value of some objects tricky.
3346 The units are just half the vertical extent of the object, which
3347 is usually quite small, so quite large numbers may be required.
3348 A value of @w{@code{-1}} aligns the lower edge of the object with
3349 the reference point of the parent object, a value of @code{0}
3350 aligns the center of the object with the reference point of the
3351 parent, and a value of @code{1} aligns the top edge of the object
3352 with the reference point of the parent. The symbols @code{DOWN},
3353 @code{CENTER}, and @code{UP} may be substituted for @w{@code{-1}},
3354 @code{0}, and @code{1}, respectively.
3356 @emph{Self-aligning objects in both directions}
3358 By setting both @code{X-offset} and @code{Y-offset}, an object may
3359 be aligned in both directions simultaneously.
3361 The following example shows how to adjust a fingering mark so
3362 that it nestles close to the note head.
3364 @lilypond[quote,verbatim,relative=2]
3366 -\tweak #'self-alignment-X #0.5 % move horizontally left
3367 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
3368 -\tweak #'self-alignment-Y #-1 % move vertically up
3373 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3375 @c Cannot document as they do not seem to operate consistently on all objects -td
3376 @c TODO investigate further
3378 The @code{aligned-on-parent} procedures are used in the same way
3379 as the @code{aligned-on-self} procedures, they difference being
3380 that they permit an object to be aligned with the @emph{edges} of
3381 the parent rather than the parent's reference point. The following
3382 example shows the difference:
3386 @lilypond[verbatim,quote]
3392 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3394 @c Cannot document as they do not seem to operate consistently on all objects -td
3395 @c TODO investigate further
3399 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3401 @node Using the break-alignable-interface
3402 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3404 @cindex align to objects
3405 @cindex break-align-symbols
3407 Rehearsal marks and bar numbers may be aligned with notation
3408 objects other than bar lines. These objects include @code{ambitus},
3409 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3410 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3411 @code{time-signature}.
3413 By default, rehearsal marks and bar numbers will be horizontally
3414 centered above the object:
3416 @lilypond[verbatim,quote,relative=1]
3417 % The rehearsal mark will be centered above the Clef
3418 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
3423 % The rehearsal mark will be centered above the Time Signature
3424 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
3430 % The rehearsal mark will be centered above the Breath Mark
3431 \override Score.RehearsalMark #'break-align-symbols = #'(breathing-sign)
3440 A list of possible target alignment objects may be specified. If
3441 some of the objects are invisible at that point due to the setting
3442 of @code{break-visibility} or the explicit visibility settings for
3443 keys and clefs, the rehearsal mark or bar number is aligned to the
3444 first object in the list which is visible. If no objects in the
3445 list are visible the object is aligned to the bar line. If the bar
3446 line is invisible the object is aligned to the place where the bar
3449 @lilypond[verbatim,quote,relative=1]
3450 % The rehearsal mark will be centered above the Key Signature
3451 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3456 % The rehearsal mark will be centered above the Clef
3457 \set Staff.explicitKeySignatureVisibility = #all-invisible
3458 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3463 % The rehearsal mark will be centered above the Bar Line
3464 \set Staff.explicitKeySignatureVisibility = #all-invisible
3465 \set Staff.explicitClefVisibility = #all-invisible
3466 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3473 The alignment of the rehearsal mark relative to the notation object
3474 can be changed, as shown in the following example. In a score with
3475 multiple staves, this setting should be done for all the staves.
3477 @lilypond[verbatim,quote,relative=1]
3478 % The RehearsalMark will be centered above the Key Signature
3479 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3485 % The RehearsalMark will be aligned with the left edge of the Key Signature
3486 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3490 % The RehearsalMark will be aligned with the right edge of the Key Signature
3491 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3497 The rehearsal mark can also be offset to the right or left of the left
3498 edge by an arbitrary amount. The units are staff-spaces:
3500 @lilypond[verbatim,quote,relative=1]
3501 % The RehearsalMark will be aligned with the left edge of the Key Signature
3502 % and then shifted right by 3.5 staff-spaces
3503 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3504 \once \override Score.KeySignature #'break-align-anchor = #3.5
3508 % The RehearsalMark will be aligned with the left edge of the Key Signature
3509 % and then shifted left by 2 staff-spaces
3510 \once \override Score.KeySignature #'break-align-anchor = #-2
3517 @node Vertical grouping of grobs
3518 @subsection Vertical grouping of grobs
3520 @c TODO Expand this section
3522 The VerticalAlignment and VerticalAxisGroup grobs work together.
3523 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3524 etc. VerticalAlignment then vertically aligns the different grobs
3525 grouped together by VerticalAxisGroup. There is usually only one
3526 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3530 @node Modifying stencils
3531 @subsection Modifying stencils
3533 All layout objects have a @code{stencil} property which is part of
3534 the @code{grob-interface}. By default, this property is usually
3535 set to a function specific to the object that is tailor-made to
3536 render the symbol which represents it in the output. For example,
3537 the standard setting for the @code{stencil} property of the
3538 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3540 The standard symbol for any object can be replaced by modifying the
3541 @code{stencil} property to reference a different, specially-written,
3542 procedure. This requires a high level of knowledge of the internal
3543 workings of LilyPond, but there is an easier way which can often
3544 produce adequate results.
3546 This is to set the @code{stencil} property to the procedure which
3547 prints text -- @code{ly:text-interface::print} -- and to add a
3548 @code{text} property to the object which is set to contain the
3549 markup text which produces the required symbol. Due to the
3550 flexibility of markup, much can be achieved -- see in particular
3551 @ref{Graphic notation inside markup}.
3553 The following example demonstrates this by changing the note head
3554 symbol to a cross within a circle.
3556 @lilypond[verbatim,quote]
3558 \once \override NoteHead #'stencil = #ly:text-interface::print
3559 \once \override NoteHead #'text = \markup {
3561 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3562 \musicglyph #"noteheads.s2cross"
3570 Any of the glyphs in the feta Font can be supplied to the
3571 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3573 @c TODO Add inserting eps files or ref to later
3575 @c TODO Add inserting Postscript or ref to later
3580 @ref{Graphic notation inside markup},
3581 @ref{Formatting text},
3582 @ref{Text markup commands},
3583 @ref{The Feta font}.
3586 @node Modifying shapes
3587 @subsection Modifying shapes
3590 * Modifying ties and slurs::
3593 @node Modifying ties and slurs
3594 @unnumberedsubsubsec Modifying ties and slurs
3596 @cindex slurs, modifying
3597 @cindex ties, modifying
3598 @cindex Bézier curves, control points
3599 @cindex control points, Bézier curves
3601 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3602 curves. If the shape of the tie or slur which is calculated
3603 automatically is not optimum, the shape may be modified manually by
3604 explicitly specifying the four control points required to define
3605 a third-order Bézier curve.
3607 Third-order or cubic Bézier curves are defined by four control
3608 points. The first and fourth control points are precisely the
3609 starting and ending points of the curve. The intermediate two
3610 control points define the shape. Animations showing how the curve
3611 is drawn can be found on the web, but the following description
3612 may be helpful. The curve starts from the first control point
3613 heading directly towards the second, gradually bending over to
3614 head towards the third and continuing to bend over to head towards
3615 the fourth, arriving there travelling directly from the third
3616 control point. The curve is entirely contained in the
3617 quadrilateral defined by the four control points.
3619 Here is an example of a case where the tie is not optimum, and
3620 where @code{\tieDown} would not help.
3622 @lilypond[verbatim,quote,relative=1]
3626 { r4 <g c,> <g c,> <g c,> }
3630 One way of improving this tie is to manually modify its control
3633 The coordinates of the Bézier control points are specified in units
3634 of staff-spaces. The X@tie{}coordinate is relative to the reference
3635 point of the note to which the tie or slur is attached, and the
3636 Y@tie{}coordinate is relative to the staff center line. The
3637 coordinates are entered as a list of four pairs of decimal numbers
3638 (reals). One approach is to estimate the coordinates of the two
3639 end points, and then guess the two intermediate points. The optimum
3640 values are then found by trial and error.
3642 It is useful to remember that a symmetric curve requires symmetric
3643 control points, and that Bézier curves have the useful property that
3644 transformations of the curve such as translation, rotation and
3645 scaling can be achieved by applying the same transformation to the
3646 curve's control points.
3648 For the example above the following override gives a satisfactory
3649 tie. Note the placement -- it has to be immediately before the note
3650 to which the start of the tie (or slur) is attached.
3652 @lilypond[verbatim,quote,relative=1]
3656 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3660 { r4 <g c,> <g c,> <g c,> }
3665 It is not possible to modify shapes of ties or slurs by changing
3666 the @code{control-points} property if there are multiple ties or slurs
3667 at the same musical moment -- the @code{\tweak} command will also not
3668 work in this case. However, the @code{tie-configuration} property of
3669 @code{TieColumn} can be overridden to set start line and direction as
3673 Internals Reference:
3674 @rinternals{TieColumn}.
3677 @node Using music functions
3678 @section Using music functions
3680 @c TODO -- add @seealso, etc. to these subsections
3682 Where tweaks need to be reused with different music expressions,
3683 it is often convenient to make the tweak part of a @emph{music
3684 function}. In this section, we discuss only @emph{substitution}
3685 functions, where the object is to substitute a variable into a
3686 piece of LilyPond input code. Other more complex functions are
3687 described in @rextend{Music functions}.
3690 * Substitution function syntax::
3691 * Substitution function examples::
3694 @node Substitution function syntax
3695 @subsection Substitution function syntax
3697 Making a function that substitutes a variable into LilyPond
3698 code is easy. The general form of these functions is
3702 #(define-music-function
3703 (parser location @var{arg1} @var{arg2} @dots{})
3704 (@var{type1?} @var{type2?} @dots{})
3706 @var{@dots{}music@dots{}}
3713 @multitable @columnfractions .33 .66
3714 @item @code{@var{argN}}
3715 @tab @var{n}th argument
3717 @item @code{@var{typeN?}}
3718 @tab a scheme @emph{type predicate} for which @code{@var{argN}}
3719 must return @code{#t}.
3721 @item @code{@var{@dots{}music@dots{}}}
3722 @tab normal LilyPond input, using @code{$} to reference arguments
3727 The @code{parser} and @code{location} arguments are mandatory, and
3728 are used in some advanced situations as described in the
3729 @q{Extending} manual (see @rextend{Music functions}). For
3730 substitution functions, just be sure to include them.
3732 The list of type predicates is also required. Some of the most
3733 common type predicates used in music functions are:
3737 cheap-list? @emph{(use instead of }@q{list?}@emph{ for faster processing)}
3747 For a list of available type predicates, see
3748 @ref{Predefined type predicates}. User-defined type predicates
3755 @ref{Predefined type predicates}.
3758 @rextend{Music functions}.
3761 @file{lily/music-scheme.cc},
3763 @file{scm/lily.scm}.
3766 @node Substitution function examples
3767 @subsection Substitution function examples
3769 This section introduces some substitution function examples.
3770 These are not intended to be exhaustive, but rather to demonstrate
3771 some of the possibilities of simple substitution functions.
3773 In the first example, a function is defined that simplifies
3774 setting the padding of a TextScript:
3776 @lilypond[quote,verbatim,ragged-right]
3778 #(define-music-function
3779 (parser location padding)
3782 \once \override TextScript #'padding = $padding
3786 c4^"piu mosso" b a b
3788 c4^"piu mosso" d e f
3790 c4^"piu mosso" fis a g
3794 In addition to numbers, we can use music expressions such
3795 as notes for arguments to music functions:
3797 @c TODO: use a better example (the music argument is redundant).
3799 @lilypond[quote,verbatim,ragged-right]
3801 #(define-music-function
3802 (parser location note)
3805 \once \override Voice.NoteHead #'stencil =
3806 #ly:text-interface::print
3807 \once \override Voice.NoteHead #'text =
3808 \markup \musicglyph #"custodes.mensural.u0"
3809 \once \override Voice.Stem #'stencil = ##f
3813 \relative c' { c4 d e f \custosNote g }
3816 Substitution functions with multiple arguments can be defined:
3818 @lilypond[quote,verbatim,ragged-right]
3820 #(define-music-function
3821 (parser location padding tempotext)
3824 \once \override Score.MetronomeMark #'padding = $padding
3825 \tempo \markup { \bold $tempotext }
3829 \tempo \markup { "Low tempo" }
3831 \tempoPadded #4.0 #"High tempo"
3836 @c TODO: add appropriate @@ref's here.