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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
793 \accepts "ImproVoice"
797 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
798 c4 c^"undress" c_"while playing :)" c }
804 These settings are defined within a @code{\context} block inside a
805 @code{\layout} block,
815 In the following discussion, the example input shown should go in place
816 of the @dots{} in the previous fragment.
818 First it is necessary to define a name for the new context:
824 Since it is similar to the @code{Voice}, we want commands that work
825 on (existing) @code{Voice}s to remain working. This is achieved by
826 giving the new context an alias @code{Voice},
832 The context will print notes and instructive texts, so we need to add
833 the engravers which provide this functionality,
836 \consists Note_heads_engraver
837 \consists Text_engraver
840 but we only need this on the center line,
843 \consists Pitch_squash_engraver
844 squashedPosition = #0
847 The @rinternals{Pitch_squash_engraver} modifies note heads (created
848 by @rinternals{Note_heads_engraver}) and sets their vertical
849 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
852 The notes look like a slash, and have no stem,
855 \override NoteHead #'style = #'slash
856 \override Stem #'transparent = ##t
857 \override Flag #'transparent = ##t
860 All these plug-ins have to cooperate, and this is achieved with a
861 special plug-in, which must be marked with the keyword @code{\type}.
862 This should always be @code{Engraver_group}.
865 \type "Engraver_group"
873 \type "Engraver_group"
874 \consists "Note_heads_engraver"
875 \consists "Text_engraver"
876 \consists Pitch_squash_engraver
877 squashedPosition = #0
878 \override NoteHead #'style = #'slash
879 \override Stem #'transparent = ##t
880 \override Flag #'transparent = ##t
886 Contexts form hierarchies. We want to hang the @code{ImproVoice}
887 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
888 modify the @code{Staff} definition with the @code{\accepts}
899 The opposite of @code{\accepts} is @code{\denies},
900 which is sometimes needed when reusing existing context definitions.
902 Putting both into a @code{\layout} block, like
912 \accepts "ImproVoice"
917 Then the output at the start of this subsection can be entered as
925 c c_"while playing :)"
932 @node Context layout order
933 @subsection Context layout order
935 @cindex contexts, layout order
939 Contexts are normally positioned in a system from top to bottom
940 in the order in which they are encountered in the input file. When
941 contexts are nested, the outer context will include inner nested
942 contexts as specified in the input file, provided the inner contexts
943 are included in the outer context's @qq{accepts} list. Nested
944 contexts which are not included in the outer context's @qq{accepts}
945 list will be repositioned below the outer context rather than nested
948 The @qq{accepts} list of a context can be changed with the
949 @code{\accepts} and @code{\denies} commands. @code{\accepts} adds a
950 context to the @qq{accepts} list and @code{\denies} removes a context
951 from the list. For example, it would not normally be desirable for
952 chord names to be nested within a @code{Staff} context, so the
953 @code{ChordNames} context is not included by default in the @qq{accepts}
954 list of the @code{Staff} context, but if this were to be required it can
957 @lilypond[verbatim,quote]
961 \chords { d1:m7 b1:min7.5- }
966 @lilypond[verbatim,quote]
970 \chords { d1:m7 b1:min7.5- }
975 \accepts "ChordNames"
981 @code{\denies} is mainly used when a new context is being based on
982 another, but the required nesting differs. For example, the
983 @code{VaticanaStaff} context is based on the @code{Staff} context, but
984 with the @code{VaticanaVoice} context substituted for the @code{Voice}
985 context in the @qq{accepts} list.
987 Note that a context will be silently created implicitly if a command
988 is encountered when there is no suitable context available to
989 contain it. This can give rise to unexpected new staves or scores.
993 @rprogram{An extra staff appears}.
996 @file{ly/engraver-init.ly}.
1000 @node Explaining the Internals Reference
1001 @section Explaining the Internals Reference
1005 * Navigating the program reference::
1006 * Layout interfaces::
1007 * Determining the grob property::
1008 * Naming conventions::
1011 @node Navigating the program reference
1012 @subsection Navigating the program reference
1014 @c TODO remove this (it's in the LM)
1015 @c Replace with more factual directions
1017 Suppose we want to move the fingering indication in the fragment
1020 @lilypond[quote,relative=2,verbatim]
1026 If you visit the documentation on fingering instructions (in
1027 @ref{Fingering instructions}), you will notice:
1032 Internals Reference: @rinternals{Fingering}.
1037 @c outdated info; probably will delete.
1039 This fragment points to two parts of the program reference: a page
1040 on @code{FingeringEvent} and one on @code{Fingering}.
1042 The page on @code{FingeringEvent} describes the properties of the music
1043 expression for the input @w{@code{-2}}. The page contains many links
1044 forward. For example, it says
1047 Accepted by: @rinternals{Fingering_engraver},
1051 That link brings us to the documentation for the Engraver, the
1055 This engraver creates the following layout objects: @rinternals{Fingering}.
1058 In other words, once the @code{FingeringEvent}s are interpreted, the
1059 @code{Fingering_engraver} plug-in will process them.
1063 @c I can't figure out what this is supposed to mean. -gp
1065 The @code{Fingering_engraver} is also listed to create
1066 @rinternals{Fingering} objects,
1068 @c old info? it doesn't make any sense to me with our current docs.
1070 second bit of information listed under @b{See also} in the Notation
1075 The programmer's reference is available as an HTML document. It is
1076 highly recommended that you read it in HTML form, either online or
1077 by downloading the HTML documentation. This section will be much more
1078 difficult to understand if you are using the
1082 Follow the link to @rinternals{Fingering}. At the top of the
1086 Fingering objects are created by: @rinternals{Fingering_engraver} and
1087 @rinternals{New_fingering_engraver}.
1090 By following related links inside the program reference, we can follow the
1091 flow of information within the program:
1095 @item @rinternals{Fingering}:
1096 @rinternals{Fingering} objects are created by:
1097 @rinternals{Fingering_engraver}
1099 @item @rinternals{Fingering_engraver}:
1100 Music types accepted: @rinternals{fingering-event}
1102 @item @rinternals{fingering-event}:
1103 Music event type @code{fingering-event} is in Music expressions named
1104 @rinternals{FingeringEvent}
1107 This path goes against the flow of information in the program: it
1108 starts from the output, and ends at the input event. You could
1109 also start at an input event, and read with the flow of
1110 information, eventually ending up at the output object(s).
1112 The program reference can also be browsed like a normal document. It
1113 contains chapters on
1115 @rinternals{Music definitions},
1118 @code{Music definitions}
1120 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1121 chapter lists all the definitions used and all properties that may be
1125 @node Layout interfaces
1126 @subsection Layout interfaces
1128 @cindex interface, layout
1129 @cindex layout interface
1132 The HTML page that we found in the previous section describes the
1133 layout object called @rinternals{Fingering}. Such an object is a
1134 symbol within the score. It has properties that store numbers (like
1135 thicknesses and directions), but also pointers to related objects. A
1136 layout object is also called a @emph{Grob}, which is short for Graphical
1137 Object. For more details about Grobs, see @rinternals{grob-interface}.
1139 The page for @code{Fingering} lists the definitions for the
1140 @code{Fingering} object. For example, the page says
1143 @code{padding} (dimension, in staff space):
1149 which means that the number will be kept at a distance of at least 0.5
1153 Each layout object may have several functions as a notational or
1154 typographical element. For example, the Fingering object
1155 has the following aspects
1159 Its size is independent of the horizontal spacing, unlike slurs or beams.
1162 It is a piece of text. Granted, it is usually a very short text.
1165 That piece of text is typeset with a font, unlike slurs or beams.
1168 Horizontally, the center of the symbol should be aligned to the
1169 center of the note head.
1172 Vertically, the symbol is placed next to the note and the staff.
1175 The vertical position is also coordinated with other superscript
1176 and subscript symbols.
1179 Each of these aspects is captured in so-called @emph{interface}s,
1180 which are listed on the @rinternals{Fingering} page at the bottom
1183 This object supports the following interfaces:
1184 @rinternals{item-interface},
1185 @rinternals{self-alignment-interface},
1186 @rinternals{side-position-interface}, @rinternals{text-interface},
1187 @rinternals{text-script-interface}, @rinternals{font-interface},
1188 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1191 Clicking any of the links will take you to the page of the respective
1192 object interface. Each interface has a number of properties. Some of
1193 them are not user-serviceable (@q{Internal properties}), but others
1196 We have been talking of @emph{the} @code{Fingering} object, but actually it
1197 does not amount to much. The initialization file (see
1198 @rlearning{Other sources of information})
1199 @file{scm/define-grobs.scm} shows the soul of the @q{object},
1204 (avoid-slur . around)
1205 (slur-padding . 0.2)
1206 (staff-padding . 0.5)
1207 (self-alignment-X . 0)
1208 (self-alignment-Y . 0)
1209 (script-priority . 100)
1210 (stencil . ,ly:text-interface::print)
1211 (direction . ,ly:script-interface::calc-direction)
1212 (font-encoding . fetaText)
1213 (font-size . -5) ; don't overlap when next to heads.
1214 (meta . ((class . Item)
1215 (interfaces . (finger-interface
1217 text-script-interface
1219 side-position-interface
1220 self-alignment-interface
1221 item-interface))))))
1225 As you can see, the @code{Fingering} object is nothing more than a
1226 bunch of variable settings, and the webpage in the Internals Reference
1227 is directly generated from this definition.
1230 @node Determining the grob property
1231 @subsection Determining the grob property
1233 @c TODO remove this (it's in the LM)
1234 @c Replace with more factual directions
1236 Recall that we wanted to change the position of the @b{2} in
1238 @lilypond[quote,relative=2,verbatim]
1244 Since the @b{2} is vertically positioned next to its note, we have to
1245 meddle with the interface associated with this positioning. This is
1246 done using @code{side-position-interface}. The page for this interface
1250 @code{side-position-interface}
1252 Position a victim object (this one) next to other objects (the
1253 support). The property @code{direction} signifies where to put the
1254 victim object relative to the support (left or right, up or down?)
1259 Below this description, the variable @code{padding} is described as
1264 (dimension, in staff space)
1266 Add this much extra space between objects that are next to each other.
1270 By increasing the value of @code{padding}, we can move the
1271 fingering away from the note head. The following command inserts
1272 3 staff spaces of white
1273 between the note and the fingering:
1275 \once \override Voice.Fingering #'padding = #3
1278 Inserting this command before the Fingering object is created,
1279 i.e., before @code{c2}, yields the following result:
1281 @lilypond[quote,relative=2,verbatim]
1282 \once \override Voice.Fingering #'padding = #3
1289 In this case, the context for this tweak is @code{Voice}. This
1290 fact can also be deduced from the program reference, for the page for
1291 the @rinternals{Fingering_engraver} plug-in says
1294 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1298 @node Naming conventions
1299 @subsection Naming conventions
1301 Another thing that is needed, is an overview of the various naming
1305 @item scheme functions: lowercase-with-hyphens (incl. one-word
1307 @item scheme functions: ly:plus-scheme-style
1308 @item music events, music classes and music properties:
1310 @item Grob interfaces: scheme-style
1311 @item backend properties: scheme-style (but X and Y!)
1312 @item contexts (and MusicExpressions and grobs): Capitalized or
1314 @item context properties: lowercaseFollowedByCamelCase
1316 Capitalized_followed_by_lowercase_and_with_underscores
1319 Questions to be answered:
1321 @item Which of these are conventions and which are rules?
1322 @item Which are rules of the underlying language, and which are
1326 @node Modifying properties
1327 @section Modifying properties
1329 @c TODO change the menu and subsection node names to use
1330 @c backslash once the new macro to handle the refs
1331 @c is available. Need to find and change all refs at
1332 @c the same time. -td
1335 * Overview of modifying properties::
1337 * The override command::
1338 * The tweak command::
1339 * set versus override::
1340 * Modifying alists::
1344 @node Overview of modifying properties
1345 @subsection Overview of modifying properties
1347 Each context is responsible for creating certain types of graphical
1348 objects. The settings used for printing these objects are also stored by
1349 context. By changing these settings, the appearance of objects can be
1352 There are two different kinds of properties stored in contexts:
1353 context properties and grob properties. Context properties are
1354 properties that apply to the context as a whole and control
1355 how the context itself is displayed. In contrast, grob properties
1356 apply to specific grob types that will be displayed in the context.
1358 The @code{\set} and @code{\unset} commands are used to change values
1359 for context properties. The @code{\override} and @code{\revert}
1360 commands are used to change values for grob properties.
1363 The syntax for this is
1366 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1369 Here @var{name} is the name of a graphical object, like
1370 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1371 variable of the formatting system (@q{grob property} or @q{layout
1372 property}). The latter is a symbol, so it must be quoted. The
1373 subsection @ref{Modifying properties}, explains what to fill in
1374 for @var{name}, @var{property}, and @var{value}. Here we only
1375 discuss the functionality of this command.
1380 \override Staff.Stem #'thickness = #4.0
1384 makes stems thicker (the default is 1.3, with staff line thickness as a
1385 unit). Since the command specifies @code{Staff} as context, it only
1386 applies to the current staff. Other staves will keep their normal
1387 appearance. Here we see the command in action:
1389 @lilypond[quote,verbatim,relative=2]
1391 \override Staff.Stem #'thickness = #4.0
1397 The @code{\override} command changes the definition of the @code{Stem}
1398 within the current @code{Staff}. After the command is interpreted
1399 all stems are thickened.
1401 Analogous to @code{\set}, the @var{context} argument may be left out,
1402 causing the default context @code{Voice} to be used. Adding
1403 @code{\once} applies the change during one timestep only.
1405 @lilypond[quote,verbatim,relative=2]
1407 \once \override Stem #'thickness = #4.0
1412 The @code{\override} must be done before the object is
1413 started. Therefore, when altering @emph{Spanner} objects such as slurs
1414 or beams, the @code{\override} command must be executed at the moment
1415 when the object is created. In this example,
1417 @lilypond[quote,verbatim,relative=2]
1418 \override Slur #'thickness = #3.0
1420 \override Beam #'beam-thickness = #0.6
1425 the slur is fatter but the beam is not. This is because the command for
1426 @code{Beam} comes after the Beam is started, so it has no effect.
1428 Analogous to @code{\unset}, the @code{\revert} command for a context
1429 undoes an @code{\override} command; like with @code{\unset}, it only
1430 affects settings that were made in the same context. In other words, the
1431 @code{\revert} in the next example does not do anything.
1434 \override Voice.Stem #'thickness = #4.0
1435 \revert Staff.Stem #'thickness
1438 Some tweakable options are called @q{subproperties} and reside inside
1439 properties. To tweak those, use commands of the form
1441 @c leave this as a long long
1443 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1450 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1457 @rinternals{Backend},
1458 @rinternals{All layout objects},
1459 @rinternals{OverrideProperty},
1460 @rinternals{RevertProperty},
1461 @rinternals{PropertySet}.
1466 The back-end is not very strict in type-checking object properties.
1467 Cyclic references in Scheme values for properties can cause hangs
1468 or crashes, or both.
1472 @node The set command
1473 @subsection The @code{@bs{}set} command
1477 @cindex changing properties
1479 Each context has a set of @emph{properties}, variables contained
1480 in that context. Context properties are changed with the @code{\set}
1481 command, which has the following syntax:
1484 \set @var{context}.@var{property} = #@var{value}
1487 @var{value} is a Scheme object, which is why it must be preceded by
1488 the @code{#}@tie{}character.
1490 Contexts properties are usually named in
1491 @code{studlyCaps}. They mostly control the translation from
1492 music to notation, e.g. @code{localKeySignature} (for determining
1493 whether to print accidentals), or @code{measurePosition} (for
1494 determining when to print a bar line). Context properties can
1495 change value over time while interpreting a piece of music;
1496 @code{measurePosition} is an obvious example of
1497 this. Context properties are modified with @code{\set}.
1499 For example, multimeasure rests will be combined into a single bar
1500 if the context property @code{skipBars} is set to @code{#t}:
1502 @lilypond[quote,verbatim,relative=2]
1504 \set Score.skipBars = ##t
1508 If the @var{context} argument is left out, then the property will be
1509 set in the current bottom context (typically @code{ChordNames},
1510 @code{Voice}, @code{TabVoice}, or @code{Lyrics}).
1512 @lilypond[quote,verbatim,relative=2]
1513 \set Score.autoBeaming = ##f
1517 \set autoBeaming = ##t
1525 The change is applied @q{on-the-fly}, during the music, so that the
1526 setting only affects the second group of eighth notes.
1528 Note that the bottom-most context does not always contain the property
1529 that you wish to change -- for example, attempting to set the
1530 @code{skipBars} property of the default bottom context, in this case
1531 @code{Voice}, will have no effect, because skipBars is a property of
1532 the @code{Score} context.
1534 @lilypond[quote,verbatim,relative=2]
1540 Contexts are hierarchical, so if an enclosing context was specified, for
1541 example @code{Staff}, then the change would also apply to all
1542 @code{Voice}s in the current staff.
1546 The @code{\unset} command:
1549 \unset @var{context}.@var{property}
1553 is used to remove the definition of @var{property} from
1554 @var{context}. This command removes
1555 the definition only if it is set in @var{context}.
1556 Properties that have been set in enclosing contexts will
1557 not be altered by an unset in an enclosed context:
1559 @lilypond[quote,verbatim,relative=2]
1560 \set Score.autoBeaming = ##t
1565 \unset Score.autoBeaming
1573 Like @code{\set}, the @var{context} argument does not have to be
1574 specified for a bottom context, so the two statements
1577 \set Voice.autoBeaming = ##t
1578 \set autoBeaming = ##t
1582 are equivalent if the current bottom context is @code{Voice}.
1586 Preceding a @code{\set} command by @code{\once} makes the
1587 setting apply to only a single time-step:
1589 @lilypond[quote,verbatim,relative=2]
1591 \once \set fontSize = #4.7
1596 A full description of all available context properties is in the
1597 internals reference, see
1599 @rinternals{Tunable context properties}.
1602 Translation @expansion{} Tunable context properties.
1607 Internals Reference:
1609 @rinternals{Tunable context properties}.
1612 @cindex grob properties
1613 @cindex properties, grob
1617 @node The override command
1618 @subsection The @code{\override} command
1620 There is a special type of context property: the grob
1621 description. Grob descriptions are named in @code{StudlyCaps}
1622 (starting with capital letters). They contain the
1623 @q{default settings} for a particular kind of grob as an
1624 association list. See @file{scm/define-grobs.scm}
1625 to see the settings for each grob description. Grob descriptions
1626 are modified with @code{\override}.
1628 @code{\override} is actually a shorthand;
1631 \override @var{context}.@var{GrobName} #'@var{property} = #@var{value}
1635 is more or less equivalent to
1637 @c leave this long line -gp
1639 \set @var{context}.@var{GrobName} =
1640 #(cons (cons '@var{property} @var{value})
1641 <previous value of @var{context}.@var{GrobName}>)
1644 The value of @code{context}.@code{GrobName} (the alist) is used to initialize
1645 the properties of individual grobs. Grobs have
1646 properties, named in Scheme style, with
1647 @code{dashed-words}. The values of grob properties change
1648 during the formatting process: formatting basically amounts
1649 to computing properties using callback functions.
1651 For example, we can increase the thickness of a note stem by
1652 overriding the @code{thickness} property of the @code{Stem}
1655 @lilypond[quote,verbatim,relative=2]
1657 \override Voice.Stem #'thickness = #3.0
1661 If no context is specified in an @code{\override}, the bottom
1664 @lilypond[quote,verbatim,relative=2]
1665 { \override Staff.Stem #'thickness = #3.0
1669 \override Stem #'thickness = #0.5
1679 @cindex reverting overrides
1680 @cindex overrides, reverting
1682 The effects of @code{\override} can be undone by @code{\revert}:
1684 @lilypond[quote,verbatim,relative=2]
1686 \override Voice.Stem #'thickness = #3.0
1688 \revert Voice.Stem #'thickness
1692 The effects of @code{\override} and @code{\revert} apply to all
1693 grobs in the affected context from the current time forward:
1695 @lilypond[quote,verbatim,relative=2]
1700 \override Staff.Stem #'thickness = #3.0
1704 \revert Staff.Stem #'thickness
1712 @cindex overriding for only one moment
1714 @code{\once} can be used with @code{\override}
1715 to affect only the current time step:
1717 @lilypond[quote,verbatim,relative=2]
1721 \override Stem #'thickness = #3.0
1725 \once \override Stem #'thickness = #3.0
1734 Commands which change output generally look like
1737 \override Voice.Stem #'thickness = #3.0
1741 To construct this tweak we must determine these bits of information:
1744 @item the context: here @code{Voice}.
1745 @item the layout object: here @code{Stem}.
1746 @item the layout property: here @code{thickness}.
1747 @item a sensible value: here @code{3.0}.
1750 Some tweakable options are called @q{subproperties} and reside inside
1751 properties. To tweak those, use commands in the form
1754 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1757 @cindex internal documentation
1758 @cindex finding graphical objects
1759 @cindex graphical object descriptions
1762 @cindex internal documentation
1764 For many properties, regardless of the data type of the property, setting the
1765 property to false (@code{#f}) will result in turning it off, causing
1766 LilyPond to ignore that property entirely. This is particularly useful for
1767 turning off grob properties which may otherwise be causing problems.
1769 We demonstrate how to glean this information from the notation manual
1770 and the program reference.
1775 Internals Reference:
1776 @rinternals{Backend}
1778 @node The tweak command
1779 @subsection The @code{\tweak} command
1784 Changing grob properties
1785 with @code{\override} causes the changes to apply to all of the
1786 given grobs in the context at the moment the change applies.
1787 Sometimes, however, it is desirable to have changes apply to just
1788 one grob, rather than to all grobs in the affected context. This is
1789 accomplished with the @code{\tweak} command, which has the following
1793 \tweak #'@code{grob-property} #@code{value}
1796 The @code{\tweak} command applies to the object that immediately
1797 follows @code{value} in the music stream.
1800 In some cases, it is possible to take a short-cut for tuning
1801 graphical objects. For objects that are created directly from
1802 an item in the input file, you can use the @code{\tweak} command.
1805 @lilypond[relative=2,verbatim,quote]
1810 \tweak #'duration-log #1
1813 -\tweak #'padding #8
1819 But the main use of the @code{\tweak} command is to modify just
1820 one of a number of notation elements which start at the same musical
1821 moment, like the notes of a chord, or tuplet brackets which start
1824 The @code{\tweak} command sets a property in the following object
1825 directly, without requiring the grob name or context to be
1826 specified. For this to work, it is necessary for the @code{\tweak}
1827 command to remain immediately adjacent to the object to which it is
1828 to apply after the input file has been converted to a music stream.
1829 This is often not the case, as many additional elements are inserted
1830 into the music stream implicitly. For example, when a note which is
1831 not part of a chord is processed, LilyPond implicitly inserts a
1832 @code{ChordEvent} event before the note, so separating the tweak
1833 from the note. However, if chord symbols are placed round the
1834 tweak and the note, the @code{\tweak} command comes after the
1835 @code{ChordEvent} in the music stream, so remaining adjacent to the
1836 note, and able to modify it.
1840 @lilypond[relative=2,verbatim,quote]
1841 <\tweak #'color #red c>4
1847 @lilypond[relative=2,verbatim,quote]
1848 \tweak #'color #red c4
1853 For an introduction to the syntax and uses of the tweak command
1854 see @rlearning{Tweaking methods}.
1856 When several similar items are placed at the same musical moment,
1857 the @code{\override} command cannot be used to modify just one of
1858 them -- this is where the @code{\tweak} command must be used.
1859 Items which may appear more than once at the same musical moment
1860 include the following:
1862 @c TODO expand to include any further uses of \tweak
1864 @item note heads of notes inside a chord
1865 @item articulation signs on a single note
1866 @item ties between notes in a chord
1867 @item tuplet brackets starting at the same time
1870 @c TODO add examples of these
1872 @cindex chord, modifying one note in
1874 In this example, the color of one note head and the type of another
1875 note head are modified within a single chord:
1877 @lilypond[relative=2,verbatim,quote]
1882 \tweak #'duration-log #1
1887 @code{\tweak} can be used to modify slurs:
1889 @lilypond[verbatim,quote,relative=1]
1890 c-\tweak #'thickness #5 ( d e f)
1894 For the @code{\tweak} command to work, it must
1895 remain immediately adjacent to the object to which it is
1896 to apply after the input file has been converted to a music stream.
1897 At times, LilyPond may insert additional items into the music stream
1898 during the parsing process. For example, when a note that is not
1899 explicitly part of a chord will be placed in a chord by LilyPond,
1900 so notes to be modified with @code{\tweak} must be placed inside
1903 @lilypond[relative=2,verbatim,quote]
1904 \tweak #'color #red c4
1905 <\tweak #'color #red c>4
1908 The @code{\tweak} command cannot be used to modify any item
1909 that does not appear explicitly in the input file. In particular
1910 it cannot be used to modify stems,
1911 beams or accidentals directly, since these are generated later by
1912 note heads, rather than by music elements in the input stream.
1913 Nor can @code{\tweak} be used to modify clefs or time
1914 signatures, since these become separated from any preceding
1915 @code{\tweak} command in the input stream by the automatic
1916 insertion of extra elements required to specify the context.
1918 Several @code{\tweak} commands may be placed before a
1919 notational element -- all affect it:
1921 @lilypond[verbatim,quote,relative=1]
1923 -\tweak #'style #'dashed-line
1924 -\tweak #'dash-fraction #0.2
1925 -\tweak #'thickness #3
1926 -\tweak #'color #red
1931 The music stream which is generated from a section of an input file,
1932 including any automatically inserted elements, may be examined,
1933 see @rextend{Displaying music expressions}. This may be helpful in
1934 determining what may be modified by a @code{\tweak} command, or
1935 in determining how to adjust the input to make a @code{\tweak}
1941 @rlearning{Tweaking methods}.
1944 @rextend{Displaying music expressions}.
1949 @cindex tweaks in a variable
1950 The @code{\tweak} command cannot be used inside a variable.
1952 @cindex tweaks in lyrics
1953 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1955 @cindex tweaking control points
1956 @cindex control points, tweaking
1958 The @code{\tweak} command will apply to only the first of several
1959 generated ties in a chord.
1961 @node set versus override
1962 @subsection @code{\set} vs. @code{\override}
1964 @c TODO -- This section is probably unnecessary now.
1967 We have seen two methods of changing properties: @code{\set} and
1968 @code{\override}. There are actually two different kinds of
1971 @code{fontSize} is a special property: it is equivalent to
1972 entering @code{\override ... #'font-size} for all pertinent
1973 objects. Since this is a common change, the special
1974 property (modified with @code{\set}) was created.
1979 @node Modifying alists
1980 @subsection Modifying alists
1982 Some user-configurable properties are internally represented as
1983 @emph{alists} (association lists), which store pairs of
1984 @emph{keys} and @emph{values}. The structure of an alist is:
1987 '((@var{key1} . @var{value1})
1988 (@var{key2} . @var{value2})
1989 (@var{key3} . @var{value3})
1993 If an alist is a grob property or @code{\paper} variable, its keys
1994 can be modified individually without affecting other keys.
1996 For example, to reduce the space between adjacent staves in a
1997 staff-group, use the @code{staff-staff-spacing} property of the
1998 @code{StaffGrouper} grob. The property is an alist with four
1999 keys: @code{basic-distance}, @code{minimum-distance},
2000 @code{padding}, and @code{stretchability}. The standard settings
2001 for this property are listed in the @qq{Backend} section of the
2002 Internals Reference (see @rinternals{StaffGrouper}):
2005 '((basic-distance . 9)
2006 (minimum-distance . 7)
2008 (stretchability . 5))
2011 One way to bring the staves closer together is by reducing the
2012 value of the @code{basic-distance} key (@code{9}) to match the
2013 value of @code{minimum-distance} (@code{7}). To modify a single
2014 key individually, use a @emph{nested declaration}:
2016 @lilypond[quote,verbatim]
2017 % default space between staves
2019 \new Staff { \clef treble c''1 }
2020 \new Staff { \clef bass c1 }
2023 % reduced space between staves
2024 \new PianoStaff \with {
2025 % this is the nested declaration
2026 \override StaffGrouper #'staff-staff-spacing #'basic-distance = #7
2028 \new Staff { \clef treble c''1 }
2029 \new Staff { \clef bass c1 }
2033 Using a nested declaration will update the specified key (such as
2034 @code{basic-distance} in the above example) without altering any
2035 other keys already set for the same property.
2037 Now suppose we want the staves to be as close as possible without
2038 overlapping. The simplest way to do this is to set all four alist
2039 keys to zero. However, it is not necessary to enter four nested
2040 declarations, one for each key. Instead, the property can be
2041 completely re-defined with one declaration, as an alist:
2043 @lilypond[quote,verbatim]
2044 \new PianoStaff \with {
2045 \override StaffGrouper #'staff-staff-spacing =
2046 #'((basic-distance . 0)
2047 (minimum-distance . 0)
2049 (stretchability . 0))
2051 \new Staff { \clef treble c''1 }
2052 \new Staff { \clef bass c1 }
2056 Note that any keys not explicitly listed in the alist definition
2057 will be reset to their @emph{default-when-unset} values. In the
2058 case of @code{staff-staff-spacing}, any unset key-values would be
2059 reset to zero (except @code{stretchability}, which takes the value
2060 of @code{basic-distance} when unset). Thus the following two
2061 declarations are equivalent:
2064 \override StaffGrouper #'staff-staff-spacing =
2065 #'((basic-distance . 7))
2067 \override StaffGrouper #'staff-staff-spacing =
2068 #'((basic-distance . 7)
2069 (minimum-distance . 0)
2071 (stretchability . 7))
2074 One (possibly unintended) consequence of this is the removal of
2075 any standard settings that are set in an initialization file and
2076 loaded each time an input file is compiled. In the above example,
2077 the standard settings for @code{padding} and
2078 @code{minimum-distance} (defined in @file{scm/define-grobs.scm})
2079 are reset to their default-when-unset values (zero for both keys).
2080 Defining a property or variable as an alist (of any size) will
2081 always reset all unset key-values to their default-when-unset
2082 values. Unless this is the intended result, it is safer to update
2083 key-values individually with a nested declaration.
2085 @warning{Nested declarations will not work for context property
2086 alists (such as @code{beamExceptions}, @code{keySignature},
2087 @code{timeSignatureSettings}, etc.). These properties can only be
2088 modified by completely re-defining them as alists.}
2091 @node Useful concepts and properties
2092 @section Useful concepts and properties
2097 * Direction and placement::
2098 * Distances and measurements::
2099 * Staff symbol properties::
2101 * Visibility of objects::
2103 * Rotating objects::
2107 @subsection Input modes
2109 The way in which the notation contained within an input file is
2110 interpreted is determined by the current input mode.
2114 This is activated with the @code{\chordmode} command, and causes
2115 input to be interpreted with the syntax of chord notation, see
2116 @ref{Chord notation}. Chords are rendered as notes on a staff.
2118 Chord mode is also activated with the @code{\chords} command.
2119 This also creates a new @code{ChordNames} context and
2120 causes the following input to be interpreted with the syntax of
2121 chord notation and rendered as chord names in the @code{ChordNames}
2122 context, see @ref{Printing chord names}.
2126 This is activated with the @code{\drummode} command, and causes
2127 input to be interpreted with the syntax of drum notation, see
2128 @ref{Basic percussion notation}.
2130 Drum mode is also activated with the @code{\drums} command.
2131 This also creates a new @code{DrumStaff} context and causes the
2132 following input to be interpreted with the syntax of drum notation
2133 and rendered as drum symbols on a drum staff, see @ref{Basic
2134 percussion notation}.
2136 @strong{Figure mode}
2138 This is activated with the @code{\figuremode} command, and causes
2139 input to be interpreted with the syntax of figured bass, see
2140 @ref{Entering figured bass}.
2142 Figure mode is also activated with the @code{\figures} command.
2143 This also creates a new @code{FiguredBass} context and causes the
2144 following input to be interpreted with the figured bass syntax
2145 and rendered as figured bass symbols in the @code{FiguredBass}
2146 context, see @ref{Introduction to figured bass}.
2148 @strong{Fret and tab modes}
2150 There are no special input modes for entering fret and tab symbols.
2152 To create tab diagrams, enter notes or chords in note mode and
2153 render them in a @code{TabStaff} context, see
2154 @ref{Default tablatures}.
2156 To create fret diagrams above a staff, you have two choices.
2157 You can either use the @code{FretBoards} context (see
2158 @ref{Automatic fret diagrams} or you can enter them as a markup
2159 above the notes using the @code{\fret-diagram} command (see
2160 @ref{Fret diagram markups}).
2162 @strong{Lyrics mode}
2164 This is activated with the @code{\lyricmode} command, and causes
2165 input to be interpreted as lyric syllables with optional durations
2166 and associated lyric modifiers, see @ref{Vocal music}.
2168 Lyric mode is also activated with the @code{\addlyrics} command.
2169 This also creates a new @code{Lyrics} context and an implicit
2170 @code{\lyricsto} command which associates the following lyrics
2171 with the preceding music.
2173 @strong{Markup mode}
2175 This is activated with the @code{\markup} command, and causes
2176 input to be interpreted with the syntax of markup, see
2177 @ref{Text markup commands}.
2179 @c silly work-around for texinfo broken-ness
2180 @c (@strong{Note...} causes a spurious cross-reference in Info)
2183 This is the default mode or it may be activated with the
2184 @code{\notemode} command. Input is interpreted as pitches,
2185 durations, markup, etc and typeset as musical notation on a staff.
2187 It is not normally necessary to specify note mode explicitly, but
2188 it may be useful to do so in certain situations, for example if you
2189 are in lyric mode, chord mode or any other mode and want to insert
2190 something that only can be done with note mode syntax.
2192 For example, to indicate dynamic markings for the verses of a
2193 choral pieces it is necessary to enter note mode to interpret
2196 @lilypond[verbatim,relative=2,quote]
2199 \notemode{\set stanza = \markup{ \dynamic f 1. } }
2203 \notemode{\set stanza = \markup{ \dynamic p 2. } }
2210 @node Direction and placement
2211 @subsection Direction and placement
2213 In typesetting music the direction and placement of many items is
2214 a matter of choice. For example, the stems of notes can
2215 be directed up or down; lyrics, dynamics, and other expressive
2216 marks may be placed above or below the staff; text may be aligned
2217 left, right or center; etc. Most of these choices may be left to
2218 be determined automatically by LilyPond, but in some cases it may
2219 be desirable to force a particular direction or placement.
2221 @strong{Articulation direction indicators}
2223 By default some directions are always up or always down (e.g.
2224 dynamics or fermata), while other things can alternate between
2225 up or down based on the stem direction (like slurs or accents).
2227 @c TODO Add table showing these
2229 The default action may be overridden by prefixing the articulation
2230 by a @emph{direction indicator}. Three direction indicators are
2231 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
2232 and @code{-} (meaning @qq{use default direction}). The direction
2233 indicator can usually be omitted, in which case @code{-} is assumed,
2234 but a direction indicator is @strong{always} required before
2237 @item @code{\tweak} commands
2238 @item @code{\markup} commands
2239 @item @code{\tag} commands
2240 @item string markups, e.g. -"string"
2241 @item fingering instructions, e.g. @w{@code{-1}}
2242 @item articulation shortcuts, e.g. @w{@code{-.}}, @w{@code{->}}, @w{@code{--}}
2245 Direction indicators affect only the next note:
2247 @lilypond[verbatim,quote,relative=2]
2254 @strong{The direction property}
2256 The position or direction of many layout objects is controlled
2257 by the @code{direction} property.
2259 The value of the @code{direction} property may be
2260 set to @code{1}, meaning @qq{up} or @qq{above}, or to @w{@code{-1}},
2261 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
2262 @code{DOWN} may be used instead of @code{1} and @w{@code{-1}}
2263 respectively. The default direction may be specified by setting
2264 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
2265 in many cases predefined commands
2266 exist to specify the direction. These are all of the form
2269 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
2272 where @code{xxxNeutral} means @qq{use the default direction}.
2273 See @rlearning{Within-staff objects}.
2275 In a few cases, arpeggio being the only common example, the value
2276 of the @code{direction} property specifies whether the object
2277 is to be placed to the right or left of the parent object. In
2278 this case @w{@code{-1}} or @code{LEFT} means @qq{to the left} and
2279 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
2280 or @code{CENTER} means @qq{use the default} direction, as before.
2283 These all have side-axis set to #X
2284 AmbitusAccidental - direction has no effect
2286 StanzaNumber - not tried
2287 TrillPitchAccidental - not tried
2288 TrillPitchGroup - not tried
2291 These indications affect all notes until they are cancelled.
2293 @lilypond[verbatim,quote,relative=2]
2303 @node Distances and measurements
2304 @subsection Distances and measurements
2306 @cindex distances, absolute
2307 @cindex distances, scaled
2314 Distances in LilyPond are of two types: absolute and scaled.
2316 Absolute distances are used for specifying margins, indents, and
2317 other page layout details, and are by default specified in
2318 millimeters. Distances may be specified in other units by
2319 following the quantity by @code{\mm}, @code{\cm},
2320 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27 of
2321 an inch). Page layout distances can also be specified in scalable
2322 units (see the following paragraph) by appending
2323 @code{\staff-space} to the quantity. Page layout is described in
2324 detail in @ref{Page layout}.
2326 Scaled distances are always specified in units of the staff-space
2327 or, rarely, the half staff-space. The staff-space is the distance
2328 between two adjacent staff lines. The default value can be changed
2329 globally by setting the global staff size, or it can be overridden
2330 locally by changing the @code{staff-space} property of
2331 @code{StaffSymbol}. Scaled distances automatically scale with any
2332 change to the either the global staff size or the
2333 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2334 automatically only with changes to the global staff size.
2335 The global staff size thus enables the overall size of a rendered
2336 score to be easily varied. For the methods of setting the global
2337 staff size see @ref{Setting the staff size}.
2341 If just a section of a score needs to be rendered to a different
2342 scale, for example an ossia section or a footnote, the global staff
2343 size cannot simply be changed as this would affect the entire score.
2344 In such cases the change in size is made by overriding both the
2345 @code{staff-space} property of @code{StaffSymbol} and the size of
2346 the fonts. A Scheme function, @code{magstep}, is available to
2347 convert from a font size change to the equivalent change in
2348 @code{staff-space}. For an explanation and an example of its use,
2349 see @rlearning{Length and thickness of objects}.
2354 @rlearning{Length and thickness of objects}.
2358 @ref{Setting the staff size}.
2361 @node Staff symbol properties
2362 @subsection Staff symbol properties
2364 @cindex adjusting staff symbol
2365 @cindex drawing staff symbol
2366 @cindex staff symbol, setting of
2368 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2369 @c Need to think of uses for these properties. Eg 'line-positions
2370 @c is used in a snippet to thicken centre line.
2371 @c If retained, add @ref to here in 1.6.2 -td
2373 The vertical position of staff lines and the number of staff lines
2374 can be defined at the same time. As the following example shows,
2375 note positions are not influenced by the staff line positions.
2377 @warning{The @code{'line-positions} property overrides the
2378 @code{'line-count} property. The number of staff lines is
2379 implicitly defined by the number of elements in the list of values
2380 for @code{'line-positions}.}
2382 @lilypond[verbatim,quote,relative=1]
2384 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
2389 The width of a staff can be modified. The units are staff
2390 spaces. The spacing of objects inside the staff is not affected by
2393 @lilypond[verbatim,quote,relative=1]
2395 \override StaffSymbol #'width = #23
2402 @subsection Spanners
2404 Many objects of musical notation extend over several notes or even
2405 several bars. Examples are slurs, beams, tuplet brackets, volta
2406 repeat brackets, crescendi, trills, and glissandi. Such objects
2407 are collectively called @qq{spanners}, and have special properties to control
2408 their appearance and behaviour. Some of these properties are common
2409 to all spanners; others are restricted to a sub-set of the spanners.
2411 All spanners support the @code{spanner-interface}. A few, essentially
2412 those that draw a straight line between the two objects, support in
2413 addition the @code{line-spanner-interface}.
2415 @unnumberedsubsubsec Using the @code{spanner-interface}
2417 This interface provides two properties that apply to several spanners.
2419 @strong{@i{The @code{minimum-length} property}}
2421 The minimum length of the spanner is specified by the
2422 @code{minimum-length} property. Increasing this usually has the
2423 necessary effect of increasing the spacing of the notes between the
2424 two end points. However, this override has no effect on
2425 many spanners, as their length is determined by other considerations.
2426 A few examples where it is effective are shown below.
2436 Works as long as callback is made:
2440 Works not at all for:
2449 @lilypond[verbatim,quote,relative=2]
2452 % increase the length of the tie
2453 -\tweak #'minimum-length #5
2457 @lilypond[verbatim,quote,relative=2]
2459 \compressFullBarRests
2461 % increase the length of the rest bar
2462 \once \override MultiMeasureRest #'minimum-length = #20
2467 @lilypond[verbatim,quote,relative=2]
2469 % increase the length of the hairpin
2470 \override Hairpin #'minimum-length = #20
2474 This override can also be used to increase the length of slurs and
2477 @lilypond[verbatim,quote,relative=2]
2480 -\tweak #'minimum-length #5
2485 -\tweak #'minimum-length #5
2489 For some layout objects, the @code{minimum-length} property becomes
2490 effective only if the @code{set-spacing-rods} procedure is called
2491 explicitly. To do this, the @code{springs-and-rods} property should
2492 be set to @code{ly:spanner::set-spacing-rods}. For example,
2493 the minimum length of a glissando has no effect unless the
2494 @code{springs-and-rods} property is set:
2496 @lilypond[verbatim,quote,relative=1]
2500 % not effective alone
2501 \once \override Glissando #'minimum-length = #20
2504 % effective only when both overrides are present
2505 \once \override Glissando #'minimum-length = #20
2506 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2510 The same is true of the @code{Beam} object:
2512 @lilypond[verbatim,quote,relative=1]
2513 % not effective alone
2514 \once \override Beam #'minimum-length = #20
2517 % effective only when both overrides are present
2518 \once \override Beam #'minimum-length = #20
2519 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2523 @strong{@i{The @code{to-barline} property}}
2525 The second useful property of the @code{spanner-interface} is
2526 @code{to-barline}. By default this is true, causing hairpins and
2527 other spanners which are terminated on the first note of a measure to
2528 end instead on the immediately preceding bar line. If set to false,
2529 the spanner will extend beyond the bar line and end on the note
2532 @lilypond[verbatim,quote,relative=2]
2533 a \< a a a a \! a a a \break
2534 \override Hairpin #'to-barline = ##f
2535 a \< a a a a \! a a a
2538 This property is not effective for all spanners. For example,
2539 setting it to @code{#t} has no effect on slurs or phrasing slurs
2540 or on other spanners for which terminating on the bar line would
2543 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2545 Objects which support the @code{line-spanner-interface} include
2548 @item @code{DynamicTextSpanner}
2549 @item @code{Glissando}
2550 @item @code{TextSpanner}
2551 @item @code{TrillSpanner}
2552 @item @code{VoiceFollower}
2555 The routine responsible for drawing the stencils for these spanners is
2556 @code{ly:line-interface::print}. This routine determines the
2557 exact location of the two end points and draws a line
2558 between them, in the style requested. The locations of the two
2559 end points of the spanner are computed on-the-fly, but it is
2560 possible to override their Y-coordinates. The
2561 properties which need to be specified are nested
2562 two levels down within the property hierarchy, but the syntax of
2563 the @code{\override} command is quite simple:
2565 @lilypond[relative=2,quote,verbatim]
2567 \once \override Glissando #'(bound-details left Y) = #3
2568 \once \override Glissando #'(bound-details right Y) = #-2
2572 The units for the @code{Y} property are @code{staff-space}s,
2573 with the center line of the staff being the zero point.
2574 For the glissando, this is the value for @code{Y} at the
2575 X-coordinate corresponding to the center point of each note head,
2576 if the line is imagined to be extended to there.
2578 If @code{Y} is not set, the value is computed from the vertical
2579 position of the corresponding attachment point of the spanner.
2581 In case of a line break, the values for the end points are
2582 specified by the @code{left-broken} and @code{right-broken}
2583 sub-lists of @code{bound-details}. For example:
2585 @lilypond[relative=2,ragged-right,verbatim,quote]
2586 \override Glissando #'breakable = ##t
2587 \override Glissando #'(bound-details right-broken Y) = #-3
2588 c1 \glissando \break
2593 A number of further properties of the @code{left} and
2594 @code{right} sub-lists of the @code{bound-details} property
2595 may be modified in the same way as @code{Y}:
2599 This sets the Y-coordinate of the end point, in @code{staff-space}s
2600 offset from the staff center line. By default, it is the center of
2601 the bound object, so a glissando points to the vertical center of
2604 For horizontal spanners, such as text spanners and trill spanners,
2605 it is hardcoded to 0.
2608 This determines where the line starts and ends in the X-direction,
2609 relative to the bound object. So, a value of @w{@code{-1}} (or
2610 @code{LEFT}) makes the line start/end at the left side of the note
2611 head it is attached to.
2614 This is the absolute X-coordinate of the end point. It is usually
2615 computed on the fly, and overriding it has little useful effect.
2618 Line spanners may have symbols at the beginning or end, which is
2619 contained in this sub-property. This is for internal use; it is
2620 recommended that @code{text} be used instead.
2623 This is a markup that is evaluated to yield the stencil. It is used
2624 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2626 @lilypond[quote,ragged-right,relative=2,verbatim]
2627 \override TextSpanner #'(bound-details left text)
2628 = \markup { \small \bold Slower }
2629 c2\startTextSpan b c a\stopTextSpan
2632 @item stencil-align-dir-y
2633 @item stencil-offset
2634 Without setting one of these, the stencil is simply put at the
2635 end-point, centered on the line, as defined by the @code{X} and
2636 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2637 or @code{stencil-offset} will move the symbol at the edge vertically
2638 relative to the end point of the line:
2640 @lilypond[relative=1,quote,verbatim]
2641 \override TextSpanner
2642 #'(bound-details left stencil-align-dir-y) = #-2
2643 \override TextSpanner
2644 #'(bound-details right stencil-align-dir-y) = #UP
2646 \override TextSpanner
2647 #'(bound-details left text) = #"ggg"
2648 \override TextSpanner
2649 #'(bound-details right text) = #"hhh"
2650 c4^\startTextSpan c c c \stopTextSpan
2653 Note that negative values move the text @emph{up}, contrary to the
2654 effect that might be expected, as a value of @w{@code{-1}} or
2655 @code{DOWN} means align the @emph{bottom} edge of the text with
2656 the spanner line. A value of @code{1} or @code{UP} aligns
2657 the top edge of the text with the spanner line.
2660 Setting this sub-property to @code{#t} produces an arrowhead at the
2664 This sub-property controls the space between the specified
2665 end point of the line and the actual end. Without padding, a
2666 glissando would start and end in the center of each note head.
2670 The music function @code{\endSpanners} terminates the spanner
2671 which starts on the immediately following note prematurely. It
2672 is terminated after exactly one note, or at the following bar line
2673 if @code{to-barline} is true and a bar line occurs before the next
2676 @lilypond[verbatim,quote,ragged-right,relative=2]
2678 c2 \startTextSpan c2 c2
2683 When using @code{\endSpanners} it is not necessary to close
2684 \startTextSpan with \stopTextSpan, nor is it necessary to close
2685 hairpins with @code{\!}.
2689 Internals Reference:
2690 @rinternals{TextSpanner},
2691 @rinternals{Glissando},
2692 @rinternals{VoiceFollower},
2693 @rinternals{TrillSpanner},
2694 @rinternals{line-spanner-interface}.
2697 @node Visibility of objects
2698 @subsection Visibility of objects
2700 @cindex objects, visibility of
2701 @cindex grobs, visibility of
2702 @cindex visibility of objects
2704 There are four main ways in which the visibility of layout objects
2705 can be controlled: their stencil can be removed, they can be made
2706 transparent, they can be colored white, or their
2707 @code{break-visibility} property can be overridden. The first
2708 three apply to all layout objects; the last to just a few -- the
2709 @emph{breakable} objects. The Learning Manual introduces these
2710 four techniques, see @rlearning{Visibility and color of objects}.
2712 There are also a few other techniques which are specific to
2713 certain layout objects. These are covered under Special
2717 * Removing the stencil::
2718 * Making objects transparent::
2719 * Painting objects white::
2720 * Using break-visibility::
2721 * Special considerations::
2725 @node Removing the stencil
2726 @unnumberedsubsubsec Removing the stencil
2728 @cindex stencil, removing
2730 Every layout object has a stencil property. By default this is set
2731 to the specific function which draws that object. If this property
2732 is overridden to @code{#f} no function will be called and the object
2733 will not be drawn. The default action can be recovered with
2736 @lilypond[quote,verbatim,relative=1]
2738 \override Score.BarLine #'stencil = ##f
2740 \revert Score.BarLine #'stencil
2744 @node Making objects transparent
2745 @unnumberedsubsubsec Making objects transparent
2747 @cindex transparent, making objects
2749 Every layout object has a transparent property which by default is
2750 set to @code{#f}. If set to @code{#t} the object still occupies
2751 space but is made invisible.
2753 @lilypond[quote,verbatim,relative=2]
2755 \once \override NoteHead #'transparent = ##t
2759 @node Painting objects white
2760 @unnumberedsubsubsec Painting objects white
2762 @cindex objects, coloring
2763 @cindex coloring objects
2765 @cindex printing order
2766 @cindex overwriting objects
2767 @cindex objects, overwriting
2768 @cindex grobs, overwriting
2770 Every layout object has a color property which by default is set
2771 to @code{black}. If this is overridden to @code{white} the object
2772 will be indistinguishable from the white background. However,
2773 if the object crosses other objects the color of the crossing
2774 points will be determined by the order in which they are drawn,
2775 and this may leave a ghostly image of the white object, as shown
2778 @lilypond[quote,verbatim,relative=2]
2779 \override Staff.Clef #'color = #white
2783 This may be avoided by changing the order of printing the objects.
2784 All layout objects have a @code{layer} property which should be set
2785 to an integer. Objects with the lowest value of @code{layer} are
2786 drawn first, then objects with progressively higher values are drawn,
2787 so objects with higher values overwrite objects with lower values.
2788 By default most objects are assigned a @code{layer} value of
2789 @code{1}, although a few objects, including @code{StaffSymbol} and
2790 @code{BarLine}, are assigned a value of @code{0}. The order of
2791 printing objects with the same value of @code{layer} is indeterminate.
2793 In the example above the white clef, with a default @code{layer}
2794 value of @code{1}, is drawn after the staff lines (default
2795 @code{layer} value @code{0}), so overwriting them. To change this,
2796 the @code{Clef} object must be given in a lower value of
2797 @code{layer}, say @w{@code{-1}}, so that it is drawn earlier:
2799 @lilypond[quote,verbatim,relative=2]
2800 \override Staff.Clef #'color = #white
2801 \override Staff.Clef #'layer = #-1
2805 @node Using break-visibility
2806 @unnumberedsubsubsec Using break-visibility
2808 @c TODO Add making other objects breakable
2810 @cindex break-visibility
2812 Most layout objects are printed only once, but some like
2813 bar lines, clefs, time signatures and key signatures, may need
2814 to be printed twice when a line break occurs -- once at the end
2815 of the line and again at the start of the next line. Such
2816 objects are called @emph{breakable}, and have a property, the
2817 @code{break-visibility} property to control their visibility
2818 at the three positions in which they may appear -- at the
2819 start of a line, within a line if they are changed, and at the
2820 end of a line if a change takes place there.
2822 For example, the time signature
2823 by default will be printed at the start of the first line, but
2824 nowhere else unless it changes, when it will be printed at the
2825 point at which the change occurs. If this change occurs at the
2826 end of a line the new time signature will be printed at the start
2827 of the next line and a cautionary time signature will be printed
2828 at the end of the previous line as well.
2830 This behaviour is controlled by the @code{break-visibility}
2831 property, which is explained in
2832 @c Leave this ref on a newline - formats incorrectly otherwise -td
2833 @rlearning{Visibility and color of objects}. This property takes
2834 a vector of three booleans which, in order, determine whether the
2835 object is printed at the end of, within the body of, or at the
2836 beginning of a line. Or to be more precise, before a line break,
2837 where there is no line break, or after a line break.
2839 Alternatively, these eight combinations may be specified
2840 by pre-defined functions, defined in @file{scm/output-lib.scm},
2841 where the last three columns indicate whether the layout objects
2842 will be visible in the positions shown at the head of the columns:
2844 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2845 @headitem Function @tab Vector @tab Before @tab At no @tab After
2846 @headitem form @tab form @tab break @tab break @tab break
2848 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2849 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2850 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2851 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2852 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2853 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2854 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2855 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2858 The default settings of @code{break-visibility} depend on the
2859 layout object. The following table shows all the layout objects
2860 of interest which are affected by @code{break-visibility} and the
2861 default setting of this property:
2863 @multitable @columnfractions .3 .3 .4
2865 @headitem Layout object @tab Usual context @tab Default setting
2867 @c omit Ambitus as it appears not to be affected by break-visibility -td
2868 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2869 @item @code{BarLine} @tab @code{Score} @tab calculated
2870 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2871 @c omit the following item until it can be explained -td
2872 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2873 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2874 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2875 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2876 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2877 @c omit KeyCancellation until it can be explained -td
2878 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2879 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2880 @c omit LeftEdge until it can be explained -td
2881 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2882 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2883 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2884 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2888 The example below shows the use of the vector form to control the
2889 visibility of bar lines:
2891 @lilypond[quote,verbatim,relative=1,ragged-right]
2894 % Remove bar line at the end of the current line
2895 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2901 Although all three components of the vector used to override
2902 @code{break-visibility} must be present, not all of them are
2903 effective with every layout object, and some combinations may
2904 even give errors. The following limitations apply:
2907 @item Bar lines cannot be printed at start of line.
2908 @item A bar number cannot be printed at the start of the first
2909 line unless it is set to be different from 1.
2910 @item Clef -- see below
2911 @item Double percent repeats are either all printed or all
2912 suppressed. Use begin-of line-invisible to print and
2913 all-invisible to suppress.
2914 @item Key signature -- see below
2915 @item OctavateEight -- see below
2918 @node Special considerations
2919 @unnumberedsubsubsec Special considerations
2921 @strong{@emph{Visibility following explicit changes}}
2923 @cindex key signature, visibility following explicit change
2924 @cindex explicitKeySignatureVisibility
2925 @cindex clef, visibility following explicit change
2926 @cindex explicitClefVisibility
2928 The @code{break-visibility} property controls the visibility of
2929 key signatures and changes of clef only at the start of lines,
2930 i.e. after a break. It has no effect on the visibility of the
2931 key signature or clef following an explicit key change or an
2932 explicit clef change within or at the end of a line. In the
2933 following example the key signature following the explicit change
2934 to B-flat major is still visible, even though @code{all-invisible}
2937 @lilypond[quote,verbatim,relative=1,ragged-right]
2940 % Try to remove all key signatures
2941 \override Staff.KeySignature #'break-visibility = #all-invisible
2949 The visibility of such explicit key signature and clef changes is
2950 controlled by the @code{explicitKeySignatureVisibility} and
2951 @code{explicitClefVisibility} properties. These are the equivalent
2952 of the @code{break-visibility} property and both take a vector of
2953 three booleans or the predefined functions listed above, exactly like
2954 @code{break-visibility}. Both are properties of the Staff context,
2955 not the layout objects themselves, and so they are set using the
2956 @code{\set} command. Both are set by default to @code{all-visible}.
2957 These properties control only the visibility of key signatures and
2958 clefs resulting from explicit changes and do not affect key
2959 signatures and clefs at the beginning of lines;
2960 @code{break-visibility} must still be overridden in the appropriate
2961 object to remove these.
2963 @lilypond[quote,verbatim,relative=1,ragged-right]
2966 \set Staff.explicitKeySignatureVisibility = #all-invisible
2967 \override Staff.KeySignature #'break-visibility = #all-invisible
2974 @strong{@emph{Visibility of cautionary accidentals}}
2976 To remove the cautionary accidentals printed at an explicit key
2977 change, set the Staff context property @code{printKeyCancellation}
2980 @lilypond[quote,verbatim,relative=1,ragged-right]
2983 \set Staff.explicitKeySignatureVisibility = #all-invisible
2984 \set Staff.printKeyCancellation = ##f
2985 \override Staff.KeySignature #'break-visibility = #all-invisible
2992 With these overrides only the accidentals before the notes remain
2993 to indicate the change of key.
2995 @c TODO Add visibility of cautionary accidentals before notes
2997 @strong{@emph{Automatic bars}}
2999 @cindex automaticBars
3000 @cindex bar lines, suppressing
3002 As a special case, the printing of bar lines can also be turned off
3003 by setting the @code{automaticBars} property in the Score context.
3004 If set to @code{#f}, bar lines will not be printed automatically;
3005 they must be explicitly created with a @code{\bar} command. Unlike
3006 the @code{\cadenzaOn} predefined command, measures are still counted.
3007 Bar generation will resume according to that count if this property
3008 is later set to @code{#t}. When set to @code{#f}, line breaks can
3009 occur only at explicit @code{\bar} commands.
3013 @strong{@emph{Octavated clefs}}
3015 @cindex octavated clefs, visibility of
3016 @cindex visibility of octavated clefs
3017 @cindex clefs, visibility of octavation
3019 The small octavation symbol on octavated clefs is produced by the
3020 @code{OctavateEight} layout object. Its visibility is automatically
3021 inherited from the @code{Clef} object, so it is not necessary to apply
3022 any required @code{break-visibility} overrides to the @code{OctavateEight}
3023 layout objects to suppress octavation symbols for invisible clefs.
3025 For explicit clef changes, the @code{explicitClefVisibility}
3026 property controls both the clef symbol and any octavation symbol
3032 @rlearning{Visibility and color of objects}
3036 @subsection Line styles
3038 Some performance indications, e.g., @i{rallentando} and
3039 @i{accelerando} and @i{trills} are written as text and are
3040 extended over many measures with lines, sometimes dotted or wavy.
3042 These all use the same routines as the glissando for drawing the
3043 texts and the lines, and tuning their behavior is therefore also
3044 done in the same way. It is done with a spanner, and the routine
3045 responsible for drawing the spanners is
3046 @code{ly:line-interface::print}. This routine determines the
3047 exact location of the two @i{span points} and draws a line
3048 between them, in the style requested.
3050 Here is an example showing the different line styles available,
3051 and how to tune them.
3053 @lilypond[relative=2,ragged-right,verbatim,quote]
3055 \once \override Glissando #'style = #'dashed-line
3057 \override Glissando #'style = #'dotted-line
3059 \override Glissando #'style = #'zigzag
3061 \override Glissando #'style = #'trill
3065 The locations of the end-points of the spanner are computed
3066 on-the-fly for every graphic object, but it is possible to
3070 @lilypond[relative=2,ragged-right,verbatim,quote]
3072 \once \override Glissando #'(bound-details right Y) = #-2
3076 The value for @code{Y} is set to @w{@code{-2}} for the right end
3077 point. The left side may be similarly adjusted by specifying
3078 @code{left} instead of @code{right}.
3080 If @code{Y} is not set, the value is computed from the vertical
3081 position of the left and right attachment points of the spanner.
3083 Other adjustments of spanners are possible, for details, see
3086 @node Rotating objects
3087 @subsection Rotating objects
3089 Both layout objects and elements of markup text can be rotated by
3090 any angle about any point, but the method of doing so differs.
3093 * Rotating layout objects::
3097 @node Rotating layout objects
3098 @unnumberedsubsubsec Rotating layout objects
3100 @cindex rotating objects
3101 @cindex objects, rotating
3103 All layout objects which support the @code{grob-interface} can be
3104 rotated by setting their @code{rotation} property. This takes a
3105 list of three items: the angle of rotation counter-clockwise,
3106 and the x and y coordinates of the point relative to the object's
3107 reference point about which the rotation is to be performed. The
3108 angle of rotation is specified in degrees and the coordinates in
3111 The angle of rotation and the coordinates of the rotation point must
3112 be determined by trial and error.
3114 @cindex hairpins, angled
3115 @cindex angled hairpins
3117 There are only a few situations where the rotation of layout
3118 objects is useful; the following example shows one situation where
3121 @lilypond[quote,verbatim,relative=1]
3123 \override Hairpin #'rotation = #'(20 -1 0)
3127 @node Rotating markup
3128 @unnumberedsubsubsec Rotating markup
3130 All markup text can be rotated to lie at any angle by prefixing it
3131 with the @code{\rotate} command. The command takes two arguments:
3132 the angle of rotation in degrees counter-clockwise and the text to
3133 be rotated. The extents of the text are not rotated: they take
3134 their values from the extremes of the x and y coordinates of the
3135 rotated text. In the following example the
3136 @code{outside-staff-priority} property for text is set to @code{#f}
3137 to disable the automatic collision avoidance, which would push some
3138 of the text too high.
3140 @lilypond[quote,verbatim,relative=1]
3141 \override TextScript #'outside-staff-priority = ##f
3142 g4^\markup { \rotate #30 "a G" }
3143 b^\markup { \rotate #30 "a B" }
3144 des^\markup { \rotate #30 "a D-Flat" }
3145 fis^\markup { \rotate #30 "an F-Sharp" }
3148 @node Advanced tweaks
3149 @section Advanced tweaks
3151 This section discusses various approaches to fine tuning the
3152 appearance of the printed score.
3155 * Aligning objects::
3156 * Vertical grouping of grobs::
3157 * Modifying stencils::
3158 * Modifying shapes::
3164 @rlearning{Tweaking output},
3165 @rlearning{Other sources of information}.
3168 @ref{Explaining the Internals Reference},
3169 @ref{Modifying properties}.
3172 @file{scm/define-grobs.scm}.
3175 @rlsr{Tweaks and overrides}.
3178 @rextend{Interfaces for programmers}.
3180 Internals Reference:
3181 @rinternals{All layout objects}.
3184 @node Aligning objects
3185 @subsection Aligning objects
3187 Graphical objects which support the @code{self-alignment-interface}
3188 and/or the @code{side-position-interface} can be aligned to a previously
3189 placed object in a variety of ways. For a list of these objects, see
3190 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
3192 All graphical objects have a reference point, a horizontal extent and a
3193 vertical extent. The horizontal extent is a pair of numbers
3194 giving the displacements from the reference point of the left and
3195 right edges, displacements to the left being negative. The vertical
3196 extent is a pair of numbers giving the displacement from the reference
3197 point to the bottom and top edges, displacements down being negative.
3199 An object's position on a staff is given by the values of the
3200 @code{X-offset} and @code{Y-offset} properties. The value of
3201 @code{X-offset} gives the displacement from the X coordinate of
3202 the reference point of the parent object, and the value of
3203 @code{Y-offset} gives the displacement from the center line of the
3204 staff. The values of @code{X-offset} and @code{Y-offset} may
3205 be set directly or may be set to be calculated by procedures in order
3206 to achieve alignment with the parent object.
3208 @warning{Many objects have special positioning considerations which
3209 cause any setting of @code{X-offset} or @code{Y-offset} to be
3210 ignored or modified, even though the object supports the
3211 @code{self-alignment-interface}. Overriding the @code{X-offset}
3212 or @code{Y-offset} properties to a fixed value causes the respective
3213 @code{self-alignment} property to be disregarded.}
3215 For example, an accidental can be repositioned vertically by setting
3216 @code{Y-offset} but any changes to @code{X-offset} have no effect.
3218 Rehearsal marks may be aligned with breakable objects such as bar
3219 lines, clef symbols, time signature symbols and key signatures. There
3220 are special properties to be found in the @code{break-aligned-interface}
3221 for positioning rehearsal marks on such objects.
3224 @ref{Using the break-alignable-interface},
3225 @rextend{Callback functions}.
3228 * Setting X-offset and Y-offset directly::
3229 * Using the side-position-interface::
3230 * Using the self-alignment-interface::
3231 * Using the break-alignable-interface::
3234 @node Setting X-offset and Y-offset directly
3235 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
3237 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
3238 properties of many objects. The following example shows three
3239 notes with the default fingering position and the positions with @code{X-offset}
3240 and @code{Y-offset} modified.
3242 @lilypond[verbatim,quote,relative=2]
3245 -\tweak #'X-offset #0
3246 -\tweak #'Y-offset #0
3249 -\tweak #'X-offset #-1
3250 -\tweak #'Y-offset #1
3256 @node Using the side-position-interface
3257 @unnumberedsubsubsec Using the @code{side-position-interface}
3259 An object which supports the @code{side-position-interface} can be
3260 placed next to its parent object so that
3261 the specified edges of the two objects touch. The object may be
3262 placed above, below, to the right or to the left of the parent.
3263 The parent cannot be specified; it is determined by the order of
3264 elements in the input stream. Most objects have the associated
3265 note head as their parent.
3267 The values of the @code{side-axis} and @code{direction} properties
3268 determine where the object is to be placed, as follows:
3270 @c TODO add an example of each to the table
3272 @multitable @columnfractions .3 .3 .3
3273 @headitem @code{side-axis} @tab @code{direction} @tab
3274 @headitem property @tab property @tab Placement
3276 @item @code{0} @tab @code{-1} @tab left
3277 @item @code{0} @tab @code{1} @tab right
3278 @item @code{1} @tab @code{-1} @tab below
3279 @item @code{1} @tab @code{1} @tab above
3283 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
3284 the procedure @code{ly:side-position-interface::x-aligned-side}.
3285 This procedure will return the correct value of @code{X-offset} to
3286 place the object to the left or right side of the parent according
3287 to value of @code{direction}.
3289 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3290 the procedure @code{ly:side-position-interface::y-aligned-side}.
3291 This procedure will return the correct value of @code{Y-offset} to
3292 place the object to the top or bottom of the parent according
3293 to value of @code{direction}.
3295 @c TODO Add examples
3297 @node Using the self-alignment-interface
3298 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3300 @emph{Self-aligning objects horizontally}
3302 The horizontal alignment of an object which supports the
3303 @code{self-alignment-interface} is controlled by the value of
3304 the @code{self-alignment-X} property, provided the object's
3305 @code{X-offset} property is set to
3306 @code{ly:self-alignment-interface::x-aligned-on-self}.
3307 @code{self-alignment-X} may be given any
3308 real value, in units of half the total X extent of the
3309 object. Negative values move the object to the right, positive
3310 to the left. A value of @code{0} centers the object on the
3311 reference point of its parent, a value of @w{@code{-1}} aligns the
3312 left edge of the object on the reference point of its parent,
3313 and a value of @code{1} aligns the right edge of the object on the
3314 reference point of its parent. The symbols @code{LEFT},
3315 @code{CENTER}, and @code{RIGHT} may be used instead of the values
3316 @w{@code{-1}}, @code{0}, and @code{1}, respectively.
3318 Normally the @code{\override} command would be used to modify the
3319 value of @code{self-alignment-X}, but the @code{\tweak} command
3320 can be used to separately align several annotations on a single
3323 @lilypond[quote,verbatim,relative=1]
3325 -\tweak #'self-alignment-X #-1
3327 -\tweak #'self-alignment-X #0
3329 -\tweak #'self-alignment-X #RIGHT
3331 -\tweak #'self-alignment-X #-2.5
3332 ^"aligned further to the right"
3335 @emph{Self-aligning objects vertically}
3337 Objects may be aligned vertically in an analogous way to aligning
3338 them horizontally if the @code{Y-offset} property is set to
3339 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3340 other mechanisms are often involved in vertical alignment: the
3341 value of @code{Y-offset} is just one variable taken into account.
3342 This may make adjusting the value of some objects tricky.
3343 The units are just half the vertical extent of the object, which
3344 is usually quite small, so quite large numbers may be required.
3345 A value of @w{@code{-1}} aligns the lower edge of the object with
3346 the reference point of the parent object, a value of @code{0}
3347 aligns the center of the object with the reference point of the
3348 parent, and a value of @code{1} aligns the top edge of the object
3349 with the reference point of the parent. The symbols @code{DOWN},
3350 @code{CENTER}, and @code{UP} may be substituted for @w{@code{-1}},
3351 @code{0}, and @code{1}, respectively.
3353 @emph{Self-aligning objects in both directions}
3355 By setting both @code{X-offset} and @code{Y-offset}, an object may
3356 be aligned in both directions simultaneously.
3358 The following example shows how to adjust a fingering mark so
3359 that it nestles close to the note head.
3361 @lilypond[quote,verbatim,relative=2]
3363 -\tweak #'self-alignment-X #0.5 % move horizontally left
3364 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
3365 -\tweak #'self-alignment-Y #-1 % move vertically up
3370 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3372 @c Cannot document as they do not seem to operate consistently on all objects -td
3373 @c TODO investigate further
3375 The @code{aligned-on-parent} procedures are used in the same way
3376 as the @code{aligned-on-self} procedures, they difference being
3377 that they permit an object to be aligned with the @emph{edges} of
3378 the parent rather than the parent's reference point. The following
3379 example shows the difference:
3383 @lilypond[verbatim,quote]
3389 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3391 @c Cannot document as they do not seem to operate consistently on all objects -td
3392 @c TODO investigate further
3396 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3398 @node Using the break-alignable-interface
3399 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3401 @cindex align to objects
3402 @cindex break-align-symbols
3404 Rehearsal marks and bar numbers may be aligned with notation
3405 objects other than bar lines. These objects include @code{ambitus},
3406 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3407 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3408 @code{time-signature}.
3410 By default, rehearsal marks and bar numbers will be horizontally
3411 centered above the object:
3413 @lilypond[verbatim,quote,relative=1]
3414 % The rehearsal mark will be centered above the Clef
3415 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
3420 % The rehearsal mark will be centered above the Time Signature
3421 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
3427 % The rehearsal mark will be centered above the Breath Mark
3428 \override Score.RehearsalMark #'break-align-symbols = #'(breathing-sign)
3437 A list of possible target alignment objects may be specified. If
3438 some of the objects are invisible at that point due to the setting
3439 of @code{break-visibility} or the explicit visibility settings for
3440 keys and clefs, the rehearsal mark or bar number is aligned to the
3441 first object in the list which is visible. If no objects in the
3442 list are visible the object is aligned to the bar line. If the bar
3443 line is invisible the object is aligned to the place where the bar
3446 @lilypond[verbatim,quote,relative=1]
3447 % The rehearsal mark will be centered above the Key Signature
3448 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3453 % The rehearsal mark will be centered above the Clef
3454 \set Staff.explicitKeySignatureVisibility = #all-invisible
3455 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3460 % The rehearsal mark will be centered above the Bar Line
3461 \set Staff.explicitKeySignatureVisibility = #all-invisible
3462 \set Staff.explicitClefVisibility = #all-invisible
3463 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3470 The alignment of the rehearsal mark relative to the notation object
3471 can be changed, as shown in the following example. In a score with
3472 multiple staves, this setting should be done for all the staves.
3474 @lilypond[verbatim,quote,relative=1]
3475 % The RehearsalMark will be centered above the Key Signature
3476 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3482 % The RehearsalMark will be aligned with the left edge of the Key Signature
3483 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3487 % The RehearsalMark will be aligned with the right edge of the Key Signature
3488 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3494 The rehearsal mark can also be offset to the right or left of the left
3495 edge by an arbitrary amount. The units are staff-spaces:
3497 @lilypond[verbatim,quote,relative=1]
3498 % The RehearsalMark will be aligned with the left edge of the Key Signature
3499 % and then shifted right by 3.5 staff-spaces
3500 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3501 \once \override Score.KeySignature #'break-align-anchor = #3.5
3505 % The RehearsalMark will be aligned with the left edge of the Key Signature
3506 % and then shifted left by 2 staff-spaces
3507 \once \override Score.KeySignature #'break-align-anchor = #-2
3514 @node Vertical grouping of grobs
3515 @subsection Vertical grouping of grobs
3517 @c TODO Expand this section
3519 The VerticalAlignment and VerticalAxisGroup grobs work together.
3520 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3521 etc. VerticalAlignment then vertically aligns the different grobs
3522 grouped together by VerticalAxisGroup. There is usually only one
3523 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3527 @node Modifying stencils
3528 @subsection Modifying stencils
3530 All layout objects have a @code{stencil} property which is part of
3531 the @code{grob-interface}. By default, this property is usually
3532 set to a function specific to the object that is tailor-made to
3533 render the symbol which represents it in the output. For example,
3534 the standard setting for the @code{stencil} property of the
3535 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3537 The standard symbol for any object can be replaced by modifying the
3538 @code{stencil} property to reference a different, specially-written,
3539 procedure. This requires a high level of knowledge of the internal
3540 workings of LilyPond, but there is an easier way which can often
3541 produce adequate results.
3543 This is to set the @code{stencil} property to the procedure which
3544 prints text -- @code{ly:text-interface::print} -- and to add a
3545 @code{text} property to the object which is set to contain the
3546 markup text which produces the required symbol. Due to the
3547 flexibility of markup, much can be achieved -- see in particular
3548 @ref{Graphic notation inside markup}.
3550 The following example demonstrates this by changing the note head
3551 symbol to a cross within a circle.
3553 @lilypond[verbatim,quote]
3555 \once \override NoteHead #'stencil = #ly:text-interface::print
3556 \once \override NoteHead #'text = \markup {
3558 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3559 \musicglyph #"noteheads.s2cross"
3567 Any of the glyphs in the feta Font can be supplied to the
3568 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3570 @c TODO Add inserting eps files or ref to later
3572 @c TODO Add inserting Postscript or ref to later
3577 @ref{Graphic notation inside markup},
3578 @ref{Formatting text},
3579 @ref{Text markup commands},
3580 @ref{The Feta font}.
3583 @node Modifying shapes
3584 @subsection Modifying shapes
3587 * Modifying ties and slurs::
3590 @node Modifying ties and slurs
3591 @unnumberedsubsubsec Modifying ties and slurs
3593 @cindex slurs, modifying
3594 @cindex ties, modifying
3595 @cindex Bézier curves, control points
3596 @cindex control points, Bézier curves
3598 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3599 curves. If the shape of the tie or slur which is calculated
3600 automatically is not optimum, the shape may be modified manually by
3601 explicitly specifying the four control points required to define
3602 a third-order Bézier curve.
3604 Third-order or cubic Bézier curves are defined by four control
3605 points. The first and fourth control points are precisely the
3606 starting and ending points of the curve. The intermediate two
3607 control points define the shape. Animations showing how the curve
3608 is drawn can be found on the web, but the following description
3609 may be helpful. The curve starts from the first control point
3610 heading directly towards the second, gradually bending over to
3611 head towards the third and continuing to bend over to head towards
3612 the fourth, arriving there travelling directly from the third
3613 control point. The curve is entirely contained in the
3614 quadrilateral defined by the four control points.
3616 Here is an example of a case where the tie is not optimum, and
3617 where @code{\tieDown} would not help.
3619 @lilypond[verbatim,quote,relative=1]
3623 { r4 <g c,> <g c,> <g c,> }
3627 One way of improving this tie is to manually modify its control
3630 The coordinates of the Bézier control points are specified in units
3631 of staff-spaces. The X@tie{}coordinate is relative to the reference
3632 point of the note to which the tie or slur is attached, and the
3633 Y@tie{}coordinate is relative to the staff center line. The
3634 coordinates are entered as a list of four pairs of decimal numbers
3635 (reals). One approach is to estimate the coordinates of the two
3636 end points, and then guess the two intermediate points. The optimum
3637 values are then found by trial and error.
3639 It is useful to remember that a symmetric curve requires symmetric
3640 control points, and that Bézier curves have the useful property that
3641 transformations of the curve such as translation, rotation and
3642 scaling can be achieved by applying the same transformation to the
3643 curve's control points.
3645 For the example above the following override gives a satisfactory
3646 tie. Note the placement -- it has to be immediately before the note
3647 to which the start of the tie (or slur) is attached.
3649 @lilypond[verbatim,quote,relative=1]
3653 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3657 { r4 <g c,> <g c,> <g c,> }
3662 It is not possible to modify shapes of ties or slurs by changing
3663 the @code{control-points} property if there are multiple ties or slurs
3664 at the same musical moment -- the @code{\tweak} command will also not
3665 work in this case. However, the @code{tie-configuration} property of
3666 @code{TieColumn} can be overridden to set start line and direction as
3670 Internals Reference:
3671 @rinternals{TieColumn}.
3674 @node Using music functions
3675 @section Using music functions
3677 @c TODO -- add @seealso, etc. to these subsections
3679 Where tweaks need to be reused with different music expressions,
3680 it is often convenient to make the tweak part of a @emph{music
3681 function}. In this section, we discuss only @emph{substitution}
3682 functions, where the object is to substitute a variable into a
3683 piece of LilyPond input code. Other more complex functions are
3684 described in @rextend{Music functions}.
3687 * Substitution function syntax::
3688 * Substitution function examples::
3691 @node Substitution function syntax
3692 @subsection Substitution function syntax
3694 Making a function that substitutes a variable into LilyPond
3695 code is easy. The general form of these functions is
3699 #(define-music-function
3700 (parser location @var{arg1} @var{arg2} @dots{})
3701 (@var{type1?} @var{type2?} @dots{})
3703 @var{@dots{}music@dots{}}
3710 @multitable @columnfractions .33 .66
3711 @item @code{@var{argN}}
3712 @tab @var{n}th argument
3714 @item @code{@var{typeN?}}
3715 @tab a scheme @emph{type predicate} for which @code{@var{argN}}
3716 must return @code{#t}.
3718 @item @code{@var{@dots{}music@dots{}}}
3719 @tab normal LilyPond input, using @code{$} to reference arguments
3724 The @code{parser} and @code{location} arguments are mandatory, and
3725 are used in some advanced situations as described in the
3726 @q{Extending} manual (see @rextend{Music functions}). For
3727 substitution functions, just be sure to include them.
3729 The list of type predicates is also required. Some of the most
3730 common type predicates used in music functions are:
3734 cheap-list? @emph{(use instead of }@q{list?}@emph{ for faster processing)}
3744 For a list of available type predicates, see
3745 @ref{Predefined type predicates}. User-defined type predicates
3752 @ref{Predefined type predicates}.
3755 @rextend{Music functions}.
3758 @file{lily/music-scheme.cc},
3760 @file{scm/lily.scm}.
3763 @node Substitution function examples
3764 @subsection Substitution function examples
3766 This section introduces some substitution function examples.
3767 These are not intended to be exhaustive, but rather to demonstrate
3768 some of the possibilities of simple substitution functions.
3770 In the first example, a function is defined that simplifies
3771 setting the padding of a TextScript:
3773 @lilypond[quote,verbatim,ragged-right]
3775 #(define-music-function
3776 (parser location padding)
3779 \once \override TextScript #'padding = $padding
3783 c4^"piu mosso" b a b
3785 c4^"piu mosso" d e f
3787 c4^"piu mosso" fis a g
3791 In addition to numbers, we can use music expressions such
3792 as notes for arguments to music functions:
3794 @c TODO: use a better example (the music argument is redundant).
3796 @lilypond[quote,verbatim,ragged-right]
3798 #(define-music-function
3799 (parser location note)
3802 \once \override Voice.NoteHead #'stencil =
3803 #ly:text-interface::print
3804 \once \override Voice.NoteHead #'text =
3805 \markup \musicglyph #"custodes.mensural.u0"
3806 \once \override Voice.Stem #'stencil = ##f
3810 \relative c' { c4 d e f \custosNote g }
3813 Substitution functions with multiple arguments can be defined:
3815 @lilypond[quote,verbatim,ragged-right]
3817 #(define-music-function
3818 (parser location padding tempotext)
3821 \once \override Score.MetronomeMark #'padding = $padding
3822 \tempo \markup { \bold $tempotext }
3826 \tempo \markup { "Low tempo" }
3828 \tempoPadded #4.0 #"High tempo"
3833 @c TODO: add appropriate @@ref's here.