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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.
727 Context changes can be placed in a variable and applied to a
728 @code{\context} definition by prepending the modification with
730 @lilypond[quote,verbatim]
733 \override Stem #'thickness = #4.0
734 \remove "Time_signature_engraver"
739 \override Stem #'thickness = #-2.0
742 melody = \relative c'' {
751 s1*0^"Small, thicker stems, no time signature"
767 @c TODO: add \with in here.
771 @node Defining new contexts
772 @subsection Defining new contexts
774 @cindex contexts, defining new
775 @cindex engravers, including in contexts
790 Specific contexts, like @code{Staff} and @code{Voice}, are made of
791 simple building blocks. It is possible to create new types of
792 contexts with different combinations of engraver plug-ins.
794 The next example shows how to build a different type of
795 @code{Voice} context from scratch. It will be similar to
796 @code{Voice}, but only prints centered slash note heads. It can be used
797 to indicate improvisation in jazz pieces,
799 @lilypond[quote,ragged-right]
802 \type "Engraver_group"
803 \consists "Note_heads_engraver"
804 \consists "Rhythmic_column_engraver"
805 \consists "Text_engraver"
806 \consists Pitch_squash_engraver
807 squashedPosition = #0
808 \override NoteHead #'style = #'slash
809 \override Stem #'transparent = ##t
810 \override Flag #'transparent = ##t
814 \accepts "ImproVoice"
818 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
819 c4 c^"undress" c_"while playing :)" c }
825 These settings are defined within a @code{\context} block inside a
826 @code{\layout} block,
836 In the following discussion, the example input shown should go in place
837 of the @dots{} in the previous fragment.
839 First it is necessary to define a name for the new context:
845 Since it is similar to the @code{Voice}, we want commands that work
846 on (existing) @code{Voice}s to remain working. This is achieved by
847 giving the new context an alias @code{Voice},
853 The context will print notes and instructive texts, so we need to add
854 the engravers which provide this functionality,
857 \consists Note_heads_engraver
858 \consists Text_engraver
861 but we only need this on the center line,
864 \consists Pitch_squash_engraver
865 squashedPosition = #0
868 The @rinternals{Pitch_squash_engraver} modifies note heads (created
869 by @rinternals{Note_heads_engraver}) and sets their vertical
870 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
873 The notes look like a slash, and have no stem,
876 \override NoteHead #'style = #'slash
877 \override Stem #'transparent = ##t
878 \override Flag #'transparent = ##t
881 All these plug-ins have to cooperate, and this is achieved with a
882 special plug-in, which must be marked with the keyword @code{\type}.
883 This should always be @code{Engraver_group}.
886 \type "Engraver_group"
894 \type "Engraver_group"
895 \consists "Note_heads_engraver"
896 \consists "Text_engraver"
897 \consists Pitch_squash_engraver
898 squashedPosition = #0
899 \override NoteHead #'style = #'slash
900 \override Stem #'transparent = ##t
901 \override Flag #'transparent = ##t
907 Contexts form hierarchies. We want to hang the @code{ImproVoice}
908 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
909 modify the @code{Staff} definition with the @code{\accepts}
920 The opposite of @code{\accepts} is @code{\denies},
921 which is sometimes needed when reusing existing context definitions.
923 Putting both into a @code{\layout} block, like
933 \accepts "ImproVoice"
938 Then the output at the start of this subsection can be entered as
946 c c_"while playing :)"
953 @node Context layout order
954 @subsection Context layout order
956 @cindex contexts, layout order
960 Contexts are normally positioned in a system from top to bottom
961 in the order in which they are encountered in the input file. When
962 contexts are nested, the outer context will include inner nested
963 contexts as specified in the input file, provided the inner contexts
964 are included in the outer context's @qq{accepts} list. Nested
965 contexts which are not included in the outer context's @qq{accepts}
966 list will be repositioned below the outer context rather than nested
969 The @qq{accepts} list of a context can be changed with the
970 @code{\accepts} and @code{\denies} commands. @code{\accepts} adds a
971 context to the @qq{accepts} list and @code{\denies} removes a context
972 from the list. For example, it would not normally be desirable for
973 chord names to be nested within a @code{Staff} context, so the
974 @code{ChordNames} context is not included by default in the @qq{accepts}
975 list of the @code{Staff} context, but if this were to be required it can
978 @lilypond[verbatim,quote]
982 \chords { d1:m7 b1:min7.5- }
987 @lilypond[verbatim,quote]
991 \chords { d1:m7 b1:min7.5- }
996 \accepts "ChordNames"
1002 @code{\denies} is mainly used when a new context is being based on
1003 another, but the required nesting differs. For example, the
1004 @code{VaticanaStaff} context is based on the @code{Staff} context, but
1005 with the @code{VaticanaVoice} context substituted for the @code{Voice}
1006 context in the @qq{accepts} list.
1008 Note that a context will be silently created implicitly if a command
1009 is encountered when there is no suitable context available to
1010 contain it. This can give rise to unexpected new staves or scores.
1014 @rprogram{An extra staff appears}.
1017 @file{ly/engraver-init.ly}.
1021 @node Explaining the Internals Reference
1022 @section Explaining the Internals Reference
1026 * Navigating the program reference::
1027 * Layout interfaces::
1028 * Determining the grob property::
1029 * Naming conventions::
1032 @node Navigating the program reference
1033 @subsection Navigating the program reference
1035 @c TODO remove this (it's in the LM)
1036 @c Replace with more factual directions
1038 Suppose we want to move the fingering indication in the fragment
1041 @lilypond[quote,relative=2,verbatim]
1047 If you visit the documentation on fingering instructions (in
1048 @ref{Fingering instructions}), you will notice:
1053 Internals Reference: @rinternals{Fingering}.
1058 @c outdated info; probably will delete.
1060 This fragment points to two parts of the program reference: a page
1061 on @code{FingeringEvent} and one on @code{Fingering}.
1063 The page on @code{FingeringEvent} describes the properties of the music
1064 expression for the input @w{@code{-2}}. The page contains many links
1065 forward. For example, it says
1068 Accepted by: @rinternals{Fingering_engraver},
1072 That link brings us to the documentation for the Engraver, the
1076 This engraver creates the following layout objects: @rinternals{Fingering}.
1079 In other words, once the @code{FingeringEvent}s are interpreted, the
1080 @code{Fingering_engraver} plug-in will process them.
1084 @c I can't figure out what this is supposed to mean. -gp
1086 The @code{Fingering_engraver} is also listed to create
1087 @rinternals{Fingering} objects,
1089 @c old info? it doesn't make any sense to me with our current docs.
1091 second bit of information listed under @b{See also} in the Notation
1096 The programmer's reference is available as an HTML document. It is
1097 highly recommended that you read it in HTML form, either online or
1098 by downloading the HTML documentation. This section will be much more
1099 difficult to understand if you are using the
1103 Follow the link to @rinternals{Fingering}. At the top of the
1107 Fingering objects are created by: @rinternals{Fingering_engraver} and
1108 @rinternals{New_fingering_engraver}.
1111 By following related links inside the program reference, we can follow the
1112 flow of information within the program:
1116 @item @rinternals{Fingering}:
1117 @rinternals{Fingering} objects are created by:
1118 @rinternals{Fingering_engraver}
1120 @item @rinternals{Fingering_engraver}:
1121 Music types accepted: @rinternals{fingering-event}
1123 @item @rinternals{fingering-event}:
1124 Music event type @code{fingering-event} is in Music expressions named
1125 @rinternals{FingeringEvent}
1128 This path goes against the flow of information in the program: it
1129 starts from the output, and ends at the input event. You could
1130 also start at an input event, and read with the flow of
1131 information, eventually ending up at the output object(s).
1133 The program reference can also be browsed like a normal document. It
1134 contains chapters on
1136 @rinternals{Music definitions},
1139 @code{Music definitions}
1141 on @rinternals{Translation}, and the @rinternals{Backend}. Every
1142 chapter lists all the definitions used and all properties that may be
1146 @node Layout interfaces
1147 @subsection Layout interfaces
1149 @cindex interface, layout
1150 @cindex layout interface
1153 The HTML page that we found in the previous section describes the
1154 layout object called @rinternals{Fingering}. Such an object is a
1155 symbol within the score. It has properties that store numbers (like
1156 thicknesses and directions), but also pointers to related objects. A
1157 layout object is also called a @emph{Grob}, which is short for Graphical
1158 Object. For more details about Grobs, see @rinternals{grob-interface}.
1160 The page for @code{Fingering} lists the definitions for the
1161 @code{Fingering} object. For example, the page says
1164 @code{padding} (dimension, in staff space):
1170 which means that the number will be kept at a distance of at least 0.5
1174 Each layout object may have several functions as a notational or
1175 typographical element. For example, the Fingering object
1176 has the following aspects
1180 Its size is independent of the horizontal spacing, unlike slurs or beams.
1183 It is a piece of text. Granted, it is usually a very short text.
1186 That piece of text is typeset with a font, unlike slurs or beams.
1189 Horizontally, the center of the symbol should be aligned to the
1190 center of the note head.
1193 Vertically, the symbol is placed next to the note and the staff.
1196 The vertical position is also coordinated with other superscript
1197 and subscript symbols.
1200 Each of these aspects is captured in so-called @emph{interface}s,
1201 which are listed on the @rinternals{Fingering} page at the bottom
1204 This object supports the following interfaces:
1205 @rinternals{item-interface},
1206 @rinternals{self-alignment-interface},
1207 @rinternals{side-position-interface}, @rinternals{text-interface},
1208 @rinternals{text-script-interface}, @rinternals{font-interface},
1209 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1212 Clicking any of the links will take you to the page of the respective
1213 object interface. Each interface has a number of properties. Some of
1214 them are not user-serviceable (@q{Internal properties}), but others
1217 We have been talking of @emph{the} @code{Fingering} object, but actually it
1218 does not amount to much. The initialization file (see
1219 @rlearning{Other sources of information})
1220 @file{scm/define-grobs.scm} shows the soul of the @q{object},
1225 (avoid-slur . around)
1226 (slur-padding . 0.2)
1227 (staff-padding . 0.5)
1228 (self-alignment-X . 0)
1229 (self-alignment-Y . 0)
1230 (script-priority . 100)
1231 (stencil . ,ly:text-interface::print)
1232 (direction . ,ly:script-interface::calc-direction)
1233 (font-encoding . fetaText)
1234 (font-size . -5) ; don't overlap when next to heads.
1235 (meta . ((class . Item)
1236 (interfaces . (finger-interface
1238 text-script-interface
1240 side-position-interface
1241 self-alignment-interface
1242 item-interface))))))
1246 As you can see, the @code{Fingering} object is nothing more than a
1247 bunch of variable settings, and the webpage in the Internals Reference
1248 is directly generated from this definition.
1251 @node Determining the grob property
1252 @subsection Determining the grob property
1254 @c TODO remove this (it's in the LM)
1255 @c Replace with more factual directions
1257 Recall that we wanted to change the position of the @b{2} in
1259 @lilypond[quote,relative=2,verbatim]
1265 Since the @b{2} is vertically positioned next to its note, we have to
1266 meddle with the interface associated with this positioning. This is
1267 done using @code{side-position-interface}. The page for this interface
1271 @code{side-position-interface}
1273 Position a victim object (this one) next to other objects (the
1274 support). The property @code{direction} signifies where to put the
1275 victim object relative to the support (left or right, up or down?)
1280 Below this description, the variable @code{padding} is described as
1285 (dimension, in staff space)
1287 Add this much extra space between objects that are next to each other.
1291 By increasing the value of @code{padding}, we can move the
1292 fingering away from the note head. The following command inserts
1293 3 staff spaces of white
1294 between the note and the fingering:
1296 \once \override Voice.Fingering #'padding = #3
1299 Inserting this command before the Fingering object is created,
1300 i.e., before @code{c2}, yields the following result:
1302 @lilypond[quote,relative=2,verbatim]
1303 \once \override Voice.Fingering #'padding = #3
1310 In this case, the context for this tweak is @code{Voice}. This
1311 fact can also be deduced from the program reference, for the page for
1312 the @rinternals{Fingering_engraver} plug-in says
1315 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1319 @node Naming conventions
1320 @subsection Naming conventions
1322 Another thing that is needed, is an overview of the various naming
1326 @item scheme functions: lowercase-with-hyphens (incl. one-word
1328 @item scheme functions: ly:plus-scheme-style
1329 @item music events, music classes and music properties:
1331 @item Grob interfaces: scheme-style
1332 @item backend properties: scheme-style (but X and Y!)
1333 @item contexts (and MusicExpressions and grobs): Capitalized or
1335 @item context properties: lowercaseFollowedByCamelCase
1337 Capitalized_followed_by_lowercase_and_with_underscores
1340 Questions to be answered:
1342 @item Which of these are conventions and which are rules?
1343 @item Which are rules of the underlying language, and which are
1347 @node Modifying properties
1348 @section Modifying properties
1350 @c TODO change the menu and subsection node names to use
1351 @c backslash once the new macro to handle the refs
1352 @c is available. Need to find and change all refs at
1353 @c the same time. -td
1356 * Overview of modifying properties::
1358 * The override command::
1359 * The tweak command::
1360 * set versus override::
1361 * Modifying alists::
1365 @node Overview of modifying properties
1366 @subsection Overview of modifying properties
1368 Each context is responsible for creating certain types of graphical
1369 objects. The settings used for printing these objects are also stored by
1370 context. By changing these settings, the appearance of objects can be
1373 There are two different kinds of properties stored in contexts:
1374 context properties and grob properties. Context properties are
1375 properties that apply to the context as a whole and control
1376 how the context itself is displayed. In contrast, grob properties
1377 apply to specific grob types that will be displayed in the context.
1379 The @code{\set} and @code{\unset} commands are used to change values
1380 for context properties. The @code{\override} and @code{\revert}
1381 commands are used to change values for grob properties.
1384 The syntax for this is
1387 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1390 Here @var{name} is the name of a graphical object, like
1391 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1392 variable of the formatting system (@q{grob property} or @q{layout
1393 property}). The latter is a symbol, so it must be quoted. The
1394 subsection @ref{Modifying properties}, explains what to fill in
1395 for @var{name}, @var{property}, and @var{value}. Here we only
1396 discuss the functionality of this command.
1401 \override Staff.Stem #'thickness = #4.0
1405 makes stems thicker (the default is 1.3, with staff line thickness as a
1406 unit). Since the command specifies @code{Staff} as context, it only
1407 applies to the current staff. Other staves will keep their normal
1408 appearance. Here we see the command in action:
1410 @lilypond[quote,verbatim,relative=2]
1412 \override Staff.Stem #'thickness = #4.0
1418 The @code{\override} command changes the definition of the @code{Stem}
1419 within the current @code{Staff}. After the command is interpreted
1420 all stems are thickened.
1422 Analogous to @code{\set}, the @var{context} argument may be left out,
1423 causing the default context @code{Voice} to be used. Adding
1424 @code{\once} applies the change during one timestep only.
1426 @lilypond[quote,verbatim,relative=2]
1428 \once \override Stem #'thickness = #4.0
1433 The @code{\override} must be done before the object is
1434 started. Therefore, when altering @emph{Spanner} objects such as slurs
1435 or beams, the @code{\override} command must be executed at the moment
1436 when the object is created. In this example,
1438 @lilypond[quote,verbatim,relative=2]
1439 \override Slur #'thickness = #3.0
1441 \override Beam #'beam-thickness = #0.6
1446 the slur is fatter but the beam is not. This is because the command for
1447 @code{Beam} comes after the Beam is started, so it has no effect.
1449 Analogous to @code{\unset}, the @code{\revert} command for a context
1450 undoes an @code{\override} command; like with @code{\unset}, it only
1451 affects settings that were made in the same context. In other words, the
1452 @code{\revert} in the next example does not do anything.
1455 \override Voice.Stem #'thickness = #4.0
1456 \revert Staff.Stem #'thickness
1459 Some tweakable options are called @q{subproperties} and reside inside
1460 properties. To tweak those, use commands of the form
1462 @c leave this as a long long
1464 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1471 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1478 @rinternals{Backend},
1479 @rinternals{All layout objects},
1480 @rinternals{OverrideProperty},
1481 @rinternals{RevertProperty},
1482 @rinternals{PropertySet}.
1487 The back-end is not very strict in type-checking object properties.
1488 Cyclic references in Scheme values for properties can cause hangs
1489 or crashes, or both.
1493 @node The set command
1494 @subsection The @code{@bs{}set} command
1498 @cindex changing properties
1500 Each context has a set of @emph{properties}, variables contained
1501 in that context. Context properties are changed with the @code{\set}
1502 command, which has the following syntax:
1505 \set @var{context}.@var{property} = #@var{value}
1508 @var{value} is a Scheme object, which is why it must be preceded by
1509 the @code{#}@tie{}character.
1511 Contexts properties are usually named in
1512 @code{studlyCaps}. They mostly control the translation from
1513 music to notation, e.g. @code{localKeySignature} (for determining
1514 whether to print accidentals), or @code{measurePosition} (for
1515 determining when to print a bar line). Context properties can
1516 change value over time while interpreting a piece of music;
1517 @code{measurePosition} is an obvious example of
1518 this. Context properties are modified with @code{\set}.
1520 For example, multimeasure rests will be combined into a single bar
1521 if the context property @code{skipBars} is set to @code{#t}:
1523 @lilypond[quote,verbatim,relative=2]
1525 \set Score.skipBars = ##t
1529 If the @var{context} argument is left out, then the property will be
1530 set in the current bottom context (typically @code{ChordNames},
1531 @code{Voice}, @code{TabVoice}, or @code{Lyrics}).
1533 @lilypond[quote,verbatim,relative=2]
1534 \set Score.autoBeaming = ##f
1538 \set autoBeaming = ##t
1546 The change is applied @q{on-the-fly}, during the music, so that the
1547 setting only affects the second group of eighth notes.
1549 Note that the bottom-most context does not always contain the property
1550 that you wish to change -- for example, attempting to set the
1551 @code{skipBars} property of the default bottom context, in this case
1552 @code{Voice}, will have no effect, because skipBars is a property of
1553 the @code{Score} context.
1555 @lilypond[quote,verbatim,relative=2]
1561 Contexts are hierarchical, so if an enclosing context was specified, for
1562 example @code{Staff}, then the change would also apply to all
1563 @code{Voice}s in the current staff.
1567 The @code{\unset} command:
1570 \unset @var{context}.@var{property}
1574 is used to remove the definition of @var{property} from
1575 @var{context}. This command removes
1576 the definition only if it is set in @var{context}.
1577 Properties that have been set in enclosing contexts will
1578 not be altered by an unset in an enclosed context:
1580 @lilypond[quote,verbatim,relative=2]
1581 \set Score.autoBeaming = ##t
1586 \unset Score.autoBeaming
1594 Like @code{\set}, the @var{context} argument does not have to be
1595 specified for a bottom context, so the two statements
1598 \set Voice.autoBeaming = ##t
1599 \set autoBeaming = ##t
1603 are equivalent if the current bottom context is @code{Voice}.
1607 Preceding a @code{\set} command by @code{\once} makes the
1608 setting apply to only a single time-step:
1610 @lilypond[quote,verbatim,relative=2]
1612 \once \set fontSize = #4.7
1617 A full description of all available context properties is in the
1618 internals reference, see
1620 @rinternals{Tunable context properties}.
1623 Translation @expansion{} Tunable context properties.
1628 Internals Reference:
1630 @rinternals{Tunable context properties}.
1633 @cindex grob properties
1634 @cindex properties, grob
1638 @node The override command
1639 @subsection The @code{\override} command
1641 There is a special type of context property: the grob
1642 description. Grob descriptions are named in @code{StudlyCaps}
1643 (starting with capital letters). They contain the
1644 @q{default settings} for a particular kind of grob as an
1645 association list. See @file{scm/define-grobs.scm}
1646 to see the settings for each grob description. Grob descriptions
1647 are modified with @code{\override}.
1649 @code{\override} is actually a shorthand;
1652 \override @var{context}.@var{GrobName} #'@var{property} = #@var{value}
1656 is more or less equivalent to
1658 @c leave this long line -gp
1660 \set @var{context}.@var{GrobName} =
1661 #(cons (cons '@var{property} @var{value})
1662 <previous value of @var{context}.@var{GrobName}>)
1665 The value of @code{context}.@code{GrobName} (the alist) is used to initialize
1666 the properties of individual grobs. Grobs have
1667 properties, named in Scheme style, with
1668 @code{dashed-words}. The values of grob properties change
1669 during the formatting process: formatting basically amounts
1670 to computing properties using callback functions.
1672 For example, we can increase the thickness of a note stem by
1673 overriding the @code{thickness} property of the @code{Stem}
1676 @lilypond[quote,verbatim,relative=2]
1678 \override Voice.Stem #'thickness = #3.0
1682 If no context is specified in an @code{\override}, the bottom
1685 @lilypond[quote,verbatim,relative=2]
1686 { \override Staff.Stem #'thickness = #3.0
1690 \override Stem #'thickness = #0.5
1700 @cindex reverting overrides
1701 @cindex overrides, reverting
1703 The effects of @code{\override} can be undone by @code{\revert}:
1705 @lilypond[quote,verbatim,relative=2]
1707 \override Voice.Stem #'thickness = #3.0
1709 \revert Voice.Stem #'thickness
1713 The effects of @code{\override} and @code{\revert} apply to all
1714 grobs in the affected context from the current time forward:
1716 @lilypond[quote,verbatim,relative=2]
1721 \override Staff.Stem #'thickness = #3.0
1725 \revert Staff.Stem #'thickness
1733 @cindex overriding for only one moment
1735 @code{\once} can be used with @code{\override}
1736 to affect only the current time step:
1738 @lilypond[quote,verbatim,relative=2]
1742 \override Stem #'thickness = #3.0
1746 \once \override Stem #'thickness = #3.0
1755 Commands which change output generally look like
1758 \override Voice.Stem #'thickness = #3.0
1762 To construct this tweak we must determine these bits of information:
1765 @item the context: here @code{Voice}.
1766 @item the layout object: here @code{Stem}.
1767 @item the layout property: here @code{thickness}.
1768 @item a sensible value: here @code{3.0}.
1771 Some tweakable options are called @q{subproperties} and reside inside
1772 properties. To tweak those, use commands in the form
1775 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1778 @cindex internal documentation
1779 @cindex finding graphical objects
1780 @cindex graphical object descriptions
1783 @cindex internal documentation
1785 For many properties, regardless of the data type of the property, setting the
1786 property to false (@code{#f}) will result in turning it off, causing
1787 LilyPond to ignore that property entirely. This is particularly useful for
1788 turning off grob properties which may otherwise be causing problems.
1790 We demonstrate how to glean this information from the notation manual
1791 and the program reference.
1796 Internals Reference:
1797 @rinternals{Backend}
1799 @node The tweak command
1800 @subsection The @code{\tweak} command
1805 Changing grob properties
1806 with @code{\override} causes the changes to apply to all of the
1807 given grobs in the context at the moment the change applies.
1808 Sometimes, however, it is desirable to have changes apply to just
1809 one grob, rather than to all grobs in the affected context. This is
1810 accomplished with the @code{\tweak} command, which has the following
1814 \tweak #'@code{grob-property} #@code{value}
1817 The @code{\tweak} command applies to the object that immediately
1818 follows @code{value} in the music stream.
1821 In some cases, it is possible to take a short-cut for tuning
1822 graphical objects. For objects that are created directly from
1823 an item in the input file, you can use the @code{\tweak} command.
1826 @lilypond[relative=2,verbatim,quote]
1831 \tweak #'duration-log #1
1834 -\tweak #'padding #8
1840 But the main use of the @code{\tweak} command is to modify just
1841 one of a number of notation elements which start at the same musical
1842 moment, like the notes of a chord, or tuplet brackets which start
1845 The @code{\tweak} command sets a property in the following object
1846 directly, without requiring the grob name or context to be
1847 specified. For this to work, it is necessary for the @code{\tweak}
1848 command to remain immediately adjacent to the object to which it is
1849 to apply after the input file has been converted to a music stream.
1850 This is often not the case, as many additional elements are inserted
1851 into the music stream implicitly. For example, when a note which is
1852 not part of a chord is processed, LilyPond implicitly inserts a
1853 @code{ChordEvent} event before the note, so separating the tweak
1854 from the note. However, if chord symbols are placed round the
1855 tweak and the note, the @code{\tweak} command comes after the
1856 @code{ChordEvent} in the music stream, so remaining adjacent to the
1857 note, and able to modify it.
1861 @lilypond[relative=2,verbatim,quote]
1862 <\tweak #'color #red c>4
1868 @lilypond[relative=2,verbatim,quote]
1869 \tweak #'color #red c4
1874 For an introduction to the syntax and uses of the tweak command
1875 see @rlearning{Tweaking methods}.
1877 When several similar items are placed at the same musical moment,
1878 the @code{\override} command cannot be used to modify just one of
1879 them -- this is where the @code{\tweak} command must be used.
1880 Items which may appear more than once at the same musical moment
1881 include the following:
1883 @c TODO expand to include any further uses of \tweak
1885 @item note heads of notes inside a chord
1886 @item articulation signs on a single note
1887 @item ties between notes in a chord
1888 @item tuplet brackets starting at the same time
1891 @c TODO add examples of these
1893 @cindex chord, modifying one note in
1895 In this example, the color of one note head and the type of another
1896 note head are modified within a single chord:
1898 @lilypond[relative=2,verbatim,quote]
1903 \tweak #'duration-log #1
1908 @code{\tweak} can be used to modify slurs:
1910 @lilypond[verbatim,quote,relative=1]
1911 c-\tweak #'thickness #5 ( d e f)
1915 For the @code{\tweak} command to work, it must
1916 remain immediately adjacent to the object to which it is
1917 to apply after the input file has been converted to a music stream.
1918 At times, LilyPond may insert additional items into the music stream
1919 during the parsing process. For example, when a note that is not
1920 explicitly part of a chord will be placed in a chord by LilyPond,
1921 so notes to be modified with @code{\tweak} must be placed inside
1924 @lilypond[relative=2,verbatim,quote]
1925 \tweak #'color #red c4
1926 <\tweak #'color #red c>4
1929 The @code{\tweak} command cannot be used to modify any item
1930 that does not appear explicitly in the input file. In particular
1931 it cannot be used to modify stems,
1932 beams or accidentals directly, since these are generated later by
1933 note heads, rather than by music elements in the input stream.
1934 Nor can @code{\tweak} be used to modify clefs or time
1935 signatures, since these become separated from any preceding
1936 @code{\tweak} command in the input stream by the automatic
1937 insertion of extra elements required to specify the context.
1939 Several @code{\tweak} commands may be placed before a
1940 notational element -- all affect it:
1942 @lilypond[verbatim,quote,relative=1]
1944 -\tweak #'style #'dashed-line
1945 -\tweak #'dash-fraction #0.2
1946 -\tweak #'thickness #3
1947 -\tweak #'color #red
1952 The music stream which is generated from a section of an input file,
1953 including any automatically inserted elements, may be examined,
1954 see @rextend{Displaying music expressions}. This may be helpful in
1955 determining what may be modified by a @code{\tweak} command, or
1956 in determining how to adjust the input to make a @code{\tweak}
1962 @rlearning{Tweaking methods}.
1965 @rextend{Displaying music expressions}.
1970 @cindex tweaks in a variable
1971 The @code{\tweak} command cannot be used inside a variable.
1973 @cindex tweaks in lyrics
1974 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1976 @cindex tweaking control points
1977 @cindex control points, tweaking
1979 The @code{\tweak} command will apply to only the first of several
1980 generated ties in a chord.
1982 @node set versus override
1983 @subsection @code{\set} vs. @code{\override}
1985 @c TODO -- This section is probably unnecessary now.
1988 We have seen two methods of changing properties: @code{\set} and
1989 @code{\override}. There are actually two different kinds of
1992 @code{fontSize} is a special property: it is equivalent to
1993 entering @code{\override ... #'font-size} for all pertinent
1994 objects. Since this is a common change, the special
1995 property (modified with @code{\set}) was created.
2000 @node Modifying alists
2001 @subsection Modifying alists
2003 Some user-configurable properties are internally represented as
2004 @emph{alists} (association lists), which store pairs of
2005 @emph{keys} and @emph{values}. The structure of an alist is:
2008 '((@var{key1} . @var{value1})
2009 (@var{key2} . @var{value2})
2010 (@var{key3} . @var{value3})
2014 If an alist is a grob property or @code{\paper} variable, its keys
2015 can be modified individually without affecting other keys.
2017 For example, to reduce the space between adjacent staves in a
2018 staff-group, use the @code{staff-staff-spacing} property of the
2019 @code{StaffGrouper} grob. The property is an alist with four
2020 keys: @code{basic-distance}, @code{minimum-distance},
2021 @code{padding}, and @code{stretchability}. The standard settings
2022 for this property are listed in the @qq{Backend} section of the
2023 Internals Reference (see @rinternals{StaffGrouper}):
2026 '((basic-distance . 9)
2027 (minimum-distance . 7)
2029 (stretchability . 5))
2032 One way to bring the staves closer together is by reducing the
2033 value of the @code{basic-distance} key (@code{9}) to match the
2034 value of @code{minimum-distance} (@code{7}). To modify a single
2035 key individually, use a @emph{nested declaration}:
2037 @lilypond[quote,verbatim]
2038 % default space between staves
2040 \new Staff { \clef treble c''1 }
2041 \new Staff { \clef bass c1 }
2044 % reduced space between staves
2045 \new PianoStaff \with {
2046 % this is the nested declaration
2047 \override StaffGrouper #'staff-staff-spacing #'basic-distance = #7
2049 \new Staff { \clef treble c''1 }
2050 \new Staff { \clef bass c1 }
2054 Using a nested declaration will update the specified key (such as
2055 @code{basic-distance} in the above example) without altering any
2056 other keys already set for the same property.
2058 Now suppose we want the staves to be as close as possible without
2059 overlapping. The simplest way to do this is to set all four alist
2060 keys to zero. However, it is not necessary to enter four nested
2061 declarations, one for each key. Instead, the property can be
2062 completely re-defined with one declaration, as an alist:
2064 @lilypond[quote,verbatim]
2065 \new PianoStaff \with {
2066 \override StaffGrouper #'staff-staff-spacing =
2067 #'((basic-distance . 0)
2068 (minimum-distance . 0)
2070 (stretchability . 0))
2072 \new Staff { \clef treble c''1 }
2073 \new Staff { \clef bass c1 }
2077 Note that any keys not explicitly listed in the alist definition
2078 will be reset to their @emph{default-when-unset} values. In the
2079 case of @code{staff-staff-spacing}, any unset key-values would be
2080 reset to zero (except @code{stretchability}, which takes the value
2081 of @code{basic-distance} when unset). Thus the following two
2082 declarations are equivalent:
2085 \override StaffGrouper #'staff-staff-spacing =
2086 #'((basic-distance . 7))
2088 \override StaffGrouper #'staff-staff-spacing =
2089 #'((basic-distance . 7)
2090 (minimum-distance . 0)
2092 (stretchability . 7))
2095 One (possibly unintended) consequence of this is the removal of
2096 any standard settings that are set in an initialization file and
2097 loaded each time an input file is compiled. In the above example,
2098 the standard settings for @code{padding} and
2099 @code{minimum-distance} (defined in @file{scm/define-grobs.scm})
2100 are reset to their default-when-unset values (zero for both keys).
2101 Defining a property or variable as an alist (of any size) will
2102 always reset all unset key-values to their default-when-unset
2103 values. Unless this is the intended result, it is safer to update
2104 key-values individually with a nested declaration.
2106 @warning{Nested declarations will not work for context property
2107 alists (such as @code{beamExceptions}, @code{keySignature},
2108 @code{timeSignatureSettings}, etc.). These properties can only be
2109 modified by completely re-defining them as alists.}
2112 @node Useful concepts and properties
2113 @section Useful concepts and properties
2118 * Direction and placement::
2119 * Distances and measurements::
2120 * Staff symbol properties::
2122 * Visibility of objects::
2124 * Rotating objects::
2128 @subsection Input modes
2130 The way in which the notation contained within an input file is
2131 interpreted is determined by the current input mode.
2135 This is activated with the @code{\chordmode} command, and causes
2136 input to be interpreted with the syntax of chord notation, see
2137 @ref{Chord notation}. Chords are rendered as notes on a staff.
2139 Chord mode is also activated with the @code{\chords} command.
2140 This also creates a new @code{ChordNames} context and
2141 causes the following input to be interpreted with the syntax of
2142 chord notation and rendered as chord names in the @code{ChordNames}
2143 context, see @ref{Printing chord names}.
2147 This is activated with the @code{\drummode} command, and causes
2148 input to be interpreted with the syntax of drum notation, see
2149 @ref{Basic percussion notation}.
2151 Drum mode is also activated with the @code{\drums} command.
2152 This also creates a new @code{DrumStaff} context and causes the
2153 following input to be interpreted with the syntax of drum notation
2154 and rendered as drum symbols on a drum staff, see @ref{Basic
2155 percussion notation}.
2157 @strong{Figure mode}
2159 This is activated with the @code{\figuremode} command, and causes
2160 input to be interpreted with the syntax of figured bass, see
2161 @ref{Entering figured bass}.
2163 Figure mode is also activated with the @code{\figures} command.
2164 This also creates a new @code{FiguredBass} context and causes the
2165 following input to be interpreted with the figured bass syntax
2166 and rendered as figured bass symbols in the @code{FiguredBass}
2167 context, see @ref{Introduction to figured bass}.
2169 @strong{Fret and tab modes}
2171 There are no special input modes for entering fret and tab symbols.
2173 To create tab diagrams, enter notes or chords in note mode and
2174 render them in a @code{TabStaff} context, see
2175 @ref{Default tablatures}.
2177 To create fret diagrams above a staff, you have two choices.
2178 You can either use the @code{FretBoards} context (see
2179 @ref{Automatic fret diagrams} or you can enter them as a markup
2180 above the notes using the @code{\fret-diagram} command (see
2181 @ref{Fret diagram markups}).
2183 @strong{Lyrics mode}
2185 This is activated with the @code{\lyricmode} command, and causes
2186 input to be interpreted as lyric syllables with optional durations
2187 and associated lyric modifiers, see @ref{Vocal music}.
2189 Lyric mode is also activated with the @code{\addlyrics} command.
2190 This also creates a new @code{Lyrics} context and an implicit
2191 @code{\lyricsto} command which associates the following lyrics
2192 with the preceding music.
2194 @strong{Markup mode}
2196 This is activated with the @code{\markup} command, and causes
2197 input to be interpreted with the syntax of markup, see
2198 @ref{Text markup commands}.
2200 @c silly work-around for texinfo broken-ness
2201 @c (@strong{Note...} causes a spurious cross-reference in Info)
2204 This is the default mode or it may be activated with the
2205 @code{\notemode} command. Input is interpreted as pitches,
2206 durations, markup, etc and typeset as musical notation on a staff.
2208 It is not normally necessary to specify note mode explicitly, but
2209 it may be useful to do so in certain situations, for example if you
2210 are in lyric mode, chord mode or any other mode and want to insert
2211 something that only can be done with note mode syntax.
2213 For example, to indicate dynamic markings for the verses of a
2214 choral pieces it is necessary to enter note mode to interpret
2217 @lilypond[verbatim,relative=2,quote]
2220 \notemode{\set stanza = \markup{ \dynamic f 1. } }
2224 \notemode{\set stanza = \markup{ \dynamic p 2. } }
2231 @node Direction and placement
2232 @subsection Direction and placement
2234 In typesetting music the direction and placement of many items is
2235 a matter of choice. For example, the stems of notes can
2236 be directed up or down; lyrics, dynamics, and other expressive
2237 marks may be placed above or below the staff; text may be aligned
2238 left, right or center; etc. Most of these choices may be left to
2239 be determined automatically by LilyPond, but in some cases it may
2240 be desirable to force a particular direction or placement.
2242 @strong{Articulation direction indicators}
2244 By default some directions are always up or always down (e.g.
2245 dynamics or fermata), while other things can alternate between
2246 up or down based on the stem direction (like slurs or accents).
2248 @c TODO Add table showing these
2250 The default action may be overridden by prefixing the articulation
2251 by a @emph{direction indicator}. Three direction indicators are
2252 available: @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down})
2253 and @code{-} (meaning @qq{use default direction}). The direction
2254 indicator can usually be omitted, in which case @code{-} is assumed,
2255 but a direction indicator is @strong{always} required before
2258 @item @code{\tweak} commands
2259 @item @code{\markup} commands
2260 @item @code{\tag} commands
2261 @item string markups, e.g. -"string"
2262 @item fingering instructions, e.g. @w{@code{-1}}
2263 @item articulation shortcuts, e.g. @w{@code{-.}}, @w{@code{->}}, @w{@code{--}}
2266 Direction indicators affect only the next note:
2268 @lilypond[verbatim,quote,relative=2]
2275 @strong{The direction property}
2277 The position or direction of many layout objects is controlled
2278 by the @code{direction} property.
2280 The value of the @code{direction} property may be
2281 set to @code{1}, meaning @qq{up} or @qq{above}, or to @w{@code{-1}},
2282 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
2283 @code{DOWN} may be used instead of @code{1} and @w{@code{-1}}
2284 respectively. The default direction may be specified by setting
2285 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
2286 in many cases predefined commands
2287 exist to specify the direction. These are all of the form
2290 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
2293 where @code{xxxNeutral} means @qq{use the default direction}.
2294 See @rlearning{Within-staff objects}.
2296 In a few cases, arpeggio being the only common example, the value
2297 of the @code{direction} property specifies whether the object
2298 is to be placed to the right or left of the parent object. In
2299 this case @w{@code{-1}} or @code{LEFT} means @qq{to the left} and
2300 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
2301 or @code{CENTER} means @qq{use the default} direction, as before.
2304 These all have side-axis set to #X
2305 AmbitusAccidental - direction has no effect
2307 StanzaNumber - not tried
2308 TrillPitchAccidental - not tried
2309 TrillPitchGroup - not tried
2312 These indications affect all notes until they are canceled.
2314 @lilypond[verbatim,quote,relative=2]
2324 @node Distances and measurements
2325 @subsection Distances and measurements
2327 @cindex distances, absolute
2328 @cindex distances, scaled
2335 Distances in LilyPond are of two types: absolute and scaled.
2337 Absolute distances are used for specifying margins, indents, and
2338 other page layout details, and are by default specified in
2339 millimeters. Distances may be specified in other units by
2340 following the quantity by @code{\mm}, @code{\cm},
2341 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27 of
2342 an inch). Page layout distances can also be specified in scalable
2343 units (see the following paragraph) by appending
2344 @code{\staff-space} to the quantity. Page layout is described in
2345 detail in @ref{Page layout}.
2347 Scaled distances are always specified in units of the staff-space
2348 or, rarely, the half staff-space. The staff-space is the distance
2349 between two adjacent staff lines. The default value can be changed
2350 globally by setting the global staff size, or it can be overridden
2351 locally by changing the @code{staff-space} property of
2352 @code{StaffSymbol}. Scaled distances automatically scale with any
2353 change to the either the global staff size or the
2354 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
2355 automatically only with changes to the global staff size.
2356 The global staff size thus enables the overall size of a rendered
2357 score to be easily varied. For the methods of setting the global
2358 staff size see @ref{Setting the staff size}.
2362 If just a section of a score needs to be rendered to a different
2363 scale, for example an ossia section or a footnote, the global staff
2364 size cannot simply be changed as this would affect the entire score.
2365 In such cases the change in size is made by overriding both the
2366 @code{staff-space} property of @code{StaffSymbol} and the size of
2367 the fonts. A Scheme function, @code{magstep}, is available to
2368 convert from a font size change to the equivalent change in
2369 @code{staff-space}. For an explanation and an example of its use,
2370 see @rlearning{Length and thickness of objects}.
2375 @rlearning{Length and thickness of objects}.
2379 @ref{Setting the staff size}.
2382 @node Staff symbol properties
2383 @subsection Staff symbol properties
2385 @cindex adjusting staff symbol
2386 @cindex drawing staff symbol
2387 @cindex staff symbol, setting of
2389 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
2390 @c Need to think of uses for these properties. Eg 'line-positions
2391 @c is used in a snippet to thicken centre line.
2392 @c If retained, add @ref to here in 1.6.2 -td
2394 The vertical position of staff lines and the number of staff lines
2395 can be defined at the same time. As the following example shows,
2396 note positions are not influenced by the staff line positions.
2398 @warning{The @code{'line-positions} property overrides the
2399 @code{'line-count} property. The number of staff lines is
2400 implicitly defined by the number of elements in the list of values
2401 for @code{'line-positions}.}
2403 @lilypond[verbatim,quote,relative=1]
2405 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
2410 The width of a staff can be modified. The units are staff
2411 spaces. The spacing of objects inside the staff is not affected by
2414 @lilypond[verbatim,quote,relative=1]
2416 \override StaffSymbol #'width = #23
2423 @subsection Spanners
2425 Many objects of musical notation extend over several notes or even
2426 several bars. Examples are slurs, beams, tuplet brackets, volta
2427 repeat brackets, crescendi, trills, and glissandi. Such objects
2428 are collectively called @qq{spanners}, and have special properties to control
2429 their appearance and behaviour. Some of these properties are common
2430 to all spanners; others are restricted to a sub-set of the spanners.
2432 All spanners support the @code{spanner-interface}. A few, essentially
2433 those that draw a straight line between the two objects, support in
2434 addition the @code{line-spanner-interface}.
2436 @unnumberedsubsubsec Using the @code{spanner-interface}
2438 This interface provides two properties that apply to several spanners.
2440 @strong{@i{The @code{minimum-length} property}}
2442 The minimum length of the spanner is specified by the
2443 @code{minimum-length} property. Increasing this usually has the
2444 necessary effect of increasing the spacing of the notes between the
2445 two end points. However, this override has no effect on
2446 many spanners, as their length is determined by other considerations.
2447 A few examples where it is effective are shown below.
2457 Works as long as callback is made:
2461 Works not at all for:
2470 @lilypond[verbatim,quote,relative=2]
2473 % increase the length of the tie
2474 -\tweak #'minimum-length #5
2478 @lilypond[verbatim,quote,relative=2]
2480 \compressFullBarRests
2482 % increase the length of the rest bar
2483 \once \override MultiMeasureRest #'minimum-length = #20
2488 @lilypond[verbatim,quote,relative=2]
2490 % increase the length of the hairpin
2491 \override Hairpin #'minimum-length = #20
2495 This override can also be used to increase the length of slurs and
2498 @lilypond[verbatim,quote,relative=2]
2501 -\tweak #'minimum-length #5
2506 -\tweak #'minimum-length #5
2510 For some layout objects, the @code{minimum-length} property becomes
2511 effective only if the @code{set-spacing-rods} procedure is called
2512 explicitly. To do this, the @code{springs-and-rods} property should
2513 be set to @code{ly:spanner::set-spacing-rods}. For example,
2514 the minimum length of a glissando has no effect unless the
2515 @code{springs-and-rods} property is set:
2517 @lilypond[verbatim,quote,relative=1]
2521 % not effective alone
2522 \once \override Glissando #'minimum-length = #20
2525 % effective only when both overrides are present
2526 \once \override Glissando #'minimum-length = #20
2527 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2531 The same is true of the @code{Beam} object:
2533 @lilypond[verbatim,quote,relative=1]
2534 % not effective alone
2535 \once \override Beam #'minimum-length = #20
2538 % effective only when both overrides are present
2539 \once \override Beam #'minimum-length = #20
2540 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2544 @strong{@i{The @code{to-barline} property}}
2546 The second useful property of the @code{spanner-interface} is
2547 @code{to-barline}. By default this is true, causing hairpins and
2548 other spanners which are terminated on the first note of a measure to
2549 end instead on the immediately preceding bar line. If set to false,
2550 the spanner will extend beyond the bar line and end on the note
2553 @lilypond[verbatim,quote,relative=2]
2554 a \< a a a a \! a a a \break
2555 \override Hairpin #'to-barline = ##f
2556 a \< a a a a \! a a a
2559 This property is not effective for all spanners. For example,
2560 setting it to @code{#t} has no effect on slurs or phrasing slurs
2561 or on other spanners for which terminating on the bar line would
2564 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2566 Objects which support the @code{line-spanner-interface} include
2569 @item @code{DynamicTextSpanner}
2570 @item @code{Glissando}
2571 @item @code{TextSpanner}
2572 @item @code{TrillSpanner}
2573 @item @code{VoiceFollower}
2576 The routine responsible for drawing the stencils for these spanners is
2577 @code{ly:line-interface::print}. This routine determines the
2578 exact location of the two end points and draws a line
2579 between them, in the style requested. The locations of the two
2580 end points of the spanner are computed on-the-fly, but it is
2581 possible to override their Y-coordinates. The
2582 properties which need to be specified are nested
2583 two levels down within the property hierarchy, but the syntax of
2584 the @code{\override} command is quite simple:
2586 @lilypond[relative=2,quote,verbatim]
2588 \once \override Glissando #'(bound-details left Y) = #3
2589 \once \override Glissando #'(bound-details right Y) = #-2
2593 The units for the @code{Y} property are @code{staff-space}s,
2594 with the center line of the staff being the zero point.
2595 For the glissando, this is the value for @code{Y} at the
2596 X-coordinate corresponding to the center point of each note head,
2597 if the line is imagined to be extended to there.
2599 If @code{Y} is not set, the value is computed from the vertical
2600 position of the corresponding attachment point of the spanner.
2602 In case of a line break, the values for the end points are
2603 specified by the @code{left-broken} and @code{right-broken}
2604 sub-lists of @code{bound-details}. For example:
2606 @lilypond[relative=2,ragged-right,verbatim,quote]
2607 \override Glissando #'breakable = ##t
2608 \override Glissando #'(bound-details right-broken Y) = #-3
2609 c1 \glissando \break
2614 A number of further properties of the @code{left} and
2615 @code{right} sub-lists of the @code{bound-details} property
2616 may be modified in the same way as @code{Y}:
2620 This sets the Y-coordinate of the end point, in @code{staff-space}s
2621 offset from the staff center line. By default, it is the center of
2622 the bound object, so a glissando points to the vertical center of
2625 For horizontal spanners, such as text spanners and trill spanners,
2626 it is hardcoded to 0.
2629 This determines where the line starts and ends in the X-direction,
2630 relative to the bound object. So, a value of @w{@code{-1}} (or
2631 @code{LEFT}) makes the line start/end at the left side of the note
2632 head it is attached to.
2635 This is the absolute X-coordinate of the end point. It is usually
2636 computed on the fly, and overriding it has little useful effect.
2639 Line spanners may have symbols at the beginning or end, which is
2640 contained in this sub-property. This is for internal use; it is
2641 recommended that @code{text} be used instead.
2644 This is a markup that is evaluated to yield the stencil. It is used
2645 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2647 @lilypond[quote,ragged-right,relative=2,verbatim]
2648 \override TextSpanner #'(bound-details left text)
2649 = \markup { \small \bold Slower }
2650 c2\startTextSpan b c a\stopTextSpan
2653 @item stencil-align-dir-y
2654 @item stencil-offset
2655 Without setting one of these, the stencil is simply put at the
2656 end-point, centered on the line, as defined by the @code{X} and
2657 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2658 or @code{stencil-offset} will move the symbol at the edge vertically
2659 relative to the end point of the line:
2661 @lilypond[relative=1,quote,verbatim]
2662 \override TextSpanner
2663 #'(bound-details left stencil-align-dir-y) = #-2
2664 \override TextSpanner
2665 #'(bound-details right stencil-align-dir-y) = #UP
2667 \override TextSpanner
2668 #'(bound-details left text) = #"ggg"
2669 \override TextSpanner
2670 #'(bound-details right text) = #"hhh"
2671 c4^\startTextSpan c c c \stopTextSpan
2674 Note that negative values move the text @emph{up}, contrary to the
2675 effect that might be expected, as a value of @w{@code{-1}} or
2676 @code{DOWN} means align the @emph{bottom} edge of the text with
2677 the spanner line. A value of @code{1} or @code{UP} aligns
2678 the top edge of the text with the spanner line.
2681 Setting this sub-property to @code{#t} produces an arrowhead at the
2685 This sub-property controls the space between the specified
2686 end point of the line and the actual end. Without padding, a
2687 glissando would start and end in the center of each note head.
2691 The music function @code{\endSpanners} terminates the spanner
2692 which starts on the immediately following note prematurely. It
2693 is terminated after exactly one note, or at the following bar line
2694 if @code{to-barline} is true and a bar line occurs before the next
2697 @lilypond[verbatim,quote,ragged-right,relative=2]
2699 c2 \startTextSpan c2 c2
2704 When using @code{\endSpanners} it is not necessary to close
2705 \startTextSpan with \stopTextSpan, nor is it necessary to close
2706 hairpins with @code{\!}.
2710 Internals Reference:
2711 @rinternals{TextSpanner},
2712 @rinternals{Glissando},
2713 @rinternals{VoiceFollower},
2714 @rinternals{TrillSpanner},
2715 @rinternals{line-spanner-interface}.
2718 @node Visibility of objects
2719 @subsection Visibility of objects
2721 @cindex objects, visibility of
2722 @cindex grobs, visibility of
2723 @cindex visibility of objects
2725 There are four main ways in which the visibility of layout objects
2726 can be controlled: their stencil can be removed, they can be made
2727 transparent, they can be colored white, or their
2728 @code{break-visibility} property can be overridden. The first
2729 three apply to all layout objects; the last to just a few -- the
2730 @emph{breakable} objects. The Learning Manual introduces these
2731 four techniques, see @rlearning{Visibility and color of objects}.
2733 There are also a few other techniques which are specific to
2734 certain layout objects. These are covered under Special
2738 * Removing the stencil::
2739 * Making objects transparent::
2740 * Painting objects white::
2741 * Using break-visibility::
2742 * Special considerations::
2746 @node Removing the stencil
2747 @unnumberedsubsubsec Removing the stencil
2749 @cindex stencil, removing
2751 Every layout object has a stencil property. By default this is set
2752 to the specific function which draws that object. If this property
2753 is overridden to @code{#f} no function will be called and the object
2754 will not be drawn. The default action can be recovered with
2757 @lilypond[quote,verbatim,relative=1]
2759 \override Score.BarLine #'stencil = ##f
2761 \revert Score.BarLine #'stencil
2765 @node Making objects transparent
2766 @unnumberedsubsubsec Making objects transparent
2768 @cindex transparent, making objects
2770 Every layout object has a transparent property which by default is
2771 set to @code{#f}. If set to @code{#t} the object still occupies
2772 space but is made invisible.
2774 @lilypond[quote,verbatim,relative=2]
2776 \once \override NoteHead #'transparent = ##t
2780 @node Painting objects white
2781 @unnumberedsubsubsec Painting objects white
2783 @cindex objects, coloring
2784 @cindex coloring objects
2786 @cindex printing order
2787 @cindex overwriting objects
2788 @cindex objects, overwriting
2789 @cindex grobs, overwriting
2791 Every layout object has a color property which by default is set
2792 to @code{black}. If this is overridden to @code{white} the object
2793 will be indistinguishable from the white background. However,
2794 if the object crosses other objects the color of the crossing
2795 points will be determined by the order in which they are drawn,
2796 and this may leave a ghostly image of the white object, as shown
2799 @lilypond[quote,verbatim,relative=2]
2800 \override Staff.Clef #'color = #white
2804 This may be avoided by changing the order of printing the objects.
2805 All layout objects have a @code{layer} property which should be set
2806 to an integer. Objects with the lowest value of @code{layer} are
2807 drawn first, then objects with progressively higher values are drawn,
2808 so objects with higher values overwrite objects with lower values.
2809 By default most objects are assigned a @code{layer} value of
2810 @code{1}, although a few objects, including @code{StaffSymbol} and
2811 @code{BarLine}, are assigned a value of @code{0}. The order of
2812 printing objects with the same value of @code{layer} is indeterminate.
2814 In the example above the white clef, with a default @code{layer}
2815 value of @code{1}, is drawn after the staff lines (default
2816 @code{layer} value @code{0}), so overwriting them. To change this,
2817 the @code{Clef} object must be given in a lower value of
2818 @code{layer}, say @w{@code{-1}}, so that it is drawn earlier:
2820 @lilypond[quote,verbatim,relative=2]
2821 \override Staff.Clef #'color = #white
2822 \override Staff.Clef #'layer = #-1
2826 @node Using break-visibility
2827 @unnumberedsubsubsec Using break-visibility
2829 @c TODO Add making other objects breakable
2831 @cindex break-visibility
2833 Most layout objects are printed only once, but some like
2834 bar lines, clefs, time signatures and key signatures, may need
2835 to be printed twice when a line break occurs -- once at the end
2836 of the line and again at the start of the next line. Such
2837 objects are called @emph{breakable}, and have a property, the
2838 @code{break-visibility} property to control their visibility
2839 at the three positions in which they may appear -- at the
2840 start of a line, within a line if they are changed, and at the
2841 end of a line if a change takes place there.
2843 For example, the time signature
2844 by default will be printed at the start of the first line, but
2845 nowhere else unless it changes, when it will be printed at the
2846 point at which the change occurs. If this change occurs at the
2847 end of a line the new time signature will be printed at the start
2848 of the next line and a cautionary time signature will be printed
2849 at the end of the previous line as well.
2851 This behaviour is controlled by the @code{break-visibility}
2852 property, which is explained in
2853 @c Leave this ref on a newline - formats incorrectly otherwise -td
2854 @rlearning{Visibility and color of objects}. This property takes
2855 a vector of three booleans which, in order, determine whether the
2856 object is printed at the end of, within the body of, or at the
2857 beginning of a line. Or to be more precise, before a line break,
2858 where there is no line break, or after a line break.
2860 Alternatively, these eight combinations may be specified
2861 by pre-defined functions, defined in @file{scm/output-lib.scm},
2862 where the last three columns indicate whether the layout objects
2863 will be visible in the positions shown at the head of the columns:
2865 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2866 @headitem Function @tab Vector @tab Before @tab At no @tab After
2867 @headitem form @tab form @tab break @tab break @tab break
2869 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2870 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2871 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2872 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2873 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2874 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2875 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2876 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2879 The default settings of @code{break-visibility} depend on the
2880 layout object. The following table shows all the layout objects
2881 of interest which are affected by @code{break-visibility} and the
2882 default setting of this property:
2884 @multitable @columnfractions .3 .3 .4
2886 @headitem Layout object @tab Usual context @tab Default setting
2888 @c omit Ambitus as it appears not to be affected by break-visibility -td
2889 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2890 @item @code{BarLine} @tab @code{Score} @tab calculated
2891 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2892 @c omit the following item until it can be explained -td
2893 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2894 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2895 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2896 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2897 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2898 @c omit KeyCancellation until it can be explained -td
2899 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2900 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2901 @c omit LeftEdge until it can be explained -td
2902 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2903 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2904 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2905 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2909 The example below shows the use of the vector form to control the
2910 visibility of bar lines:
2912 @lilypond[quote,verbatim,relative=1,ragged-right]
2915 % Remove bar line at the end of the current line
2916 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2922 Although all three components of the vector used to override
2923 @code{break-visibility} must be present, not all of them are
2924 effective with every layout object, and some combinations may
2925 even give errors. The following limitations apply:
2928 @item Bar lines cannot be printed at start of line.
2929 @item A bar number cannot be printed at the start of the first
2930 line unless it is set to be different from 1.
2931 @item Clef -- see below
2932 @item Double percent repeats are either all printed or all
2933 suppressed. Use begin-of line-invisible to print and
2934 all-invisible to suppress.
2935 @item Key signature -- see below
2936 @item OctavateEight -- see below
2939 @node Special considerations
2940 @unnumberedsubsubsec Special considerations
2942 @strong{@emph{Visibility following explicit changes}}
2944 @cindex key signature, visibility following explicit change
2945 @cindex explicitKeySignatureVisibility
2946 @cindex clef, visibility following explicit change
2947 @cindex explicitClefVisibility
2949 The @code{break-visibility} property controls the visibility of
2950 key signatures and changes of clef only at the start of lines,
2951 i.e. after a break. It has no effect on the visibility of the
2952 key signature or clef following an explicit key change or an
2953 explicit clef change within or at the end of a line. In the
2954 following example the key signature following the explicit change
2955 to B-flat major is still visible, even though @code{all-invisible}
2958 @lilypond[quote,verbatim,relative=1,ragged-right]
2961 % Try to remove all key signatures
2962 \override Staff.KeySignature #'break-visibility = #all-invisible
2970 The visibility of such explicit key signature and clef changes is
2971 controlled by the @code{explicitKeySignatureVisibility} and
2972 @code{explicitClefVisibility} properties. These are the equivalent
2973 of the @code{break-visibility} property and both take a vector of
2974 three booleans or the predefined functions listed above, exactly like
2975 @code{break-visibility}. Both are properties of the Staff context,
2976 not the layout objects themselves, and so they are set using the
2977 @code{\set} command. Both are set by default to @code{all-visible}.
2978 These properties control only the visibility of key signatures and
2979 clefs resulting from explicit changes and do not affect key
2980 signatures and clefs at the beginning of lines;
2981 @code{break-visibility} must still be overridden in the appropriate
2982 object to remove these.
2984 @lilypond[quote,verbatim,relative=1,ragged-right]
2987 \set Staff.explicitKeySignatureVisibility = #all-invisible
2988 \override Staff.KeySignature #'break-visibility = #all-invisible
2995 @strong{@emph{Visibility of cautionary accidentals}}
2997 To remove the cautionary accidentals printed at an explicit key
2998 change, set the Staff context property @code{printKeyCancellation}
3001 @lilypond[quote,verbatim,relative=1,ragged-right]
3004 \set Staff.explicitKeySignatureVisibility = #all-invisible
3005 \set Staff.printKeyCancellation = ##f
3006 \override Staff.KeySignature #'break-visibility = #all-invisible
3013 With these overrides only the accidentals before the notes remain
3014 to indicate the change of key.
3016 @c TODO Add visibility of cautionary accidentals before notes
3018 @strong{@emph{Automatic bars}}
3020 @cindex automaticBars
3021 @cindex bar lines, suppressing
3023 As a special case, the printing of bar lines can also be turned off
3024 by setting the @code{automaticBars} property in the Score context.
3025 If set to @code{#f}, bar lines will not be printed automatically;
3026 they must be explicitly created with a @code{\bar} command. Unlike
3027 the @code{\cadenzaOn} predefined command, measures are still counted.
3028 Bar generation will resume according to that count if this property
3029 is later set to @code{#t}. When set to @code{#f}, line breaks can
3030 occur only at explicit @code{\bar} commands.
3034 @strong{@emph{Octavated clefs}}
3036 @cindex octavated clefs, visibility of
3037 @cindex visibility of octavated clefs
3038 @cindex clefs, visibility of octavation
3040 The small octavation symbol on octavated clefs is produced by the
3041 @code{OctavateEight} layout object. Its visibility is automatically
3042 inherited from the @code{Clef} object, so it is not necessary to apply
3043 any required @code{break-visibility} overrides to the @code{OctavateEight}
3044 layout objects to suppress octavation symbols for invisible clefs.
3046 For explicit clef changes, the @code{explicitClefVisibility}
3047 property controls both the clef symbol and any octavation symbol
3053 @rlearning{Visibility and color of objects}
3057 @subsection Line styles
3059 Some performance indications, e.g., @i{rallentando} and
3060 @i{accelerando} and @i{trills} are written as text and are
3061 extended over many measures with lines, sometimes dotted or wavy.
3063 These all use the same routines as the glissando for drawing the
3064 texts and the lines, and tuning their behavior is therefore also
3065 done in the same way. It is done with a spanner, and the routine
3066 responsible for drawing the spanners is
3067 @code{ly:line-interface::print}. This routine determines the
3068 exact location of the two @i{span points} and draws a line
3069 between them, in the style requested.
3071 Here is an example showing the different line styles available,
3072 and how to tune them.
3074 @lilypond[relative=2,ragged-right,verbatim,quote]
3076 \once \override Glissando #'style = #'dashed-line
3078 \override Glissando #'style = #'dotted-line
3080 \override Glissando #'style = #'zigzag
3082 \override Glissando #'style = #'trill
3086 The locations of the end-points of the spanner are computed
3087 on-the-fly for every graphic object, but it is possible to
3091 @lilypond[relative=2,ragged-right,verbatim,quote]
3093 \once \override Glissando #'(bound-details right Y) = #-2
3097 The value for @code{Y} is set to @w{@code{-2}} for the right end
3098 point. The left side may be similarly adjusted by specifying
3099 @code{left} instead of @code{right}.
3101 If @code{Y} is not set, the value is computed from the vertical
3102 position of the left and right attachment points of the spanner.
3104 Other adjustments of spanners are possible, for details, see
3107 @node Rotating objects
3108 @subsection Rotating objects
3110 Both layout objects and elements of markup text can be rotated by
3111 any angle about any point, but the method of doing so differs.
3114 * Rotating layout objects::
3118 @node Rotating layout objects
3119 @unnumberedsubsubsec Rotating layout objects
3121 @cindex rotating objects
3122 @cindex objects, rotating
3124 All layout objects which support the @code{grob-interface} can be
3125 rotated by setting their @code{rotation} property. This takes a
3126 list of three items: the angle of rotation counter-clockwise,
3127 and the x and y coordinates of the point relative to the object's
3128 reference point about which the rotation is to be performed. The
3129 angle of rotation is specified in degrees and the coordinates in
3132 The angle of rotation and the coordinates of the rotation point must
3133 be determined by trial and error.
3135 @cindex hairpins, angled
3136 @cindex angled hairpins
3138 There are only a few situations where the rotation of layout
3139 objects is useful; the following example shows one situation where
3142 @lilypond[quote,verbatim,relative=1]
3144 \override Hairpin #'rotation = #'(20 -1 0)
3148 @node Rotating markup
3149 @unnumberedsubsubsec Rotating markup
3151 All markup text can be rotated to lie at any angle by prefixing it
3152 with the @code{\rotate} command. The command takes two arguments:
3153 the angle of rotation in degrees counter-clockwise and the text to
3154 be rotated. The extents of the text are not rotated: they take
3155 their values from the extremes of the x and y coordinates of the
3156 rotated text. In the following example the
3157 @code{outside-staff-priority} property for text is set to @code{#f}
3158 to disable the automatic collision avoidance, which would push some
3159 of the text too high.
3161 @lilypond[quote,verbatim,relative=1]
3162 \override TextScript #'outside-staff-priority = ##f
3163 g4^\markup { \rotate #30 "a G" }
3164 b^\markup { \rotate #30 "a B" }
3165 des^\markup { \rotate #30 "a D-Flat" }
3166 fis^\markup { \rotate #30 "an F-Sharp" }
3169 @node Advanced tweaks
3170 @section Advanced tweaks
3172 This section discusses various approaches to fine tuning the
3173 appearance of the printed score.
3176 * Aligning objects::
3177 * Vertical grouping of grobs::
3178 * Modifying stencils::
3179 * Modifying shapes::
3180 * Unpure-pure containers::
3186 @rlearning{Tweaking output},
3187 @rlearning{Other sources of information}.
3190 @ref{Explaining the Internals Reference},
3191 @ref{Modifying properties}.
3194 @file{scm/define-grobs.scm}.
3197 @rlsr{Tweaks and overrides}.
3200 @rextend{Interfaces for programmers}.
3202 Internals Reference:
3203 @rinternals{All layout objects}.
3206 @node Aligning objects
3207 @subsection Aligning objects
3209 Graphical objects which support the @code{self-alignment-interface}
3210 and/or the @code{side-position-interface} can be aligned to a previously
3211 placed object in a variety of ways. For a list of these objects, see
3212 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
3214 All graphical objects have a reference point, a horizontal extent and a
3215 vertical extent. The horizontal extent is a pair of numbers
3216 giving the displacements from the reference point of the left and
3217 right edges, displacements to the left being negative. The vertical
3218 extent is a pair of numbers giving the displacement from the reference
3219 point to the bottom and top edges, displacements down being negative.
3221 An object's position on a staff is given by the values of the
3222 @code{X-offset} and @code{Y-offset} properties. The value of
3223 @code{X-offset} gives the displacement from the X coordinate of
3224 the reference point of the parent object, and the value of
3225 @code{Y-offset} gives the displacement from the center line of the
3226 staff. The values of @code{X-offset} and @code{Y-offset} may
3227 be set directly or may be set to be calculated by procedures in order
3228 to achieve alignment with the parent object.
3230 @warning{Many objects have special positioning considerations which
3231 cause any setting of @code{X-offset} or @code{Y-offset} to be
3232 ignored or modified, even though the object supports the
3233 @code{self-alignment-interface}. Overriding the @code{X-offset}
3234 or @code{Y-offset} properties to a fixed value causes the respective
3235 @code{self-alignment} property to be disregarded.}
3237 For example, an accidental can be repositioned vertically by setting
3238 @code{Y-offset} but any changes to @code{X-offset} have no effect.
3240 Rehearsal marks may be aligned with breakable objects such as bar
3241 lines, clef symbols, time signature symbols and key signatures. There
3242 are special properties to be found in the @code{break-aligned-interface}
3243 for positioning rehearsal marks on such objects.
3246 @ref{Using the break-alignable-interface},
3247 @rextend{Callback functions}.
3250 * Setting X-offset and Y-offset directly::
3251 * Using the side-position-interface::
3252 * Using the self-alignment-interface::
3253 * Using the break-alignable-interface::
3256 @node Setting X-offset and Y-offset directly
3257 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
3259 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
3260 properties of many objects. The following example shows three
3261 notes with the default fingering position and the positions with @code{X-offset}
3262 and @code{Y-offset} modified.
3264 @lilypond[verbatim,quote,relative=2]
3267 -\tweak #'X-offset #0
3268 -\tweak #'Y-offset #0
3271 -\tweak #'X-offset #-1
3272 -\tweak #'Y-offset #1
3278 @node Using the side-position-interface
3279 @unnumberedsubsubsec Using the @code{side-position-interface}
3281 An object which supports the @code{side-position-interface} can be
3282 placed next to its parent object so that
3283 the specified edges of the two objects touch. The object may be
3284 placed above, below, to the right or to the left of the parent.
3285 The parent cannot be specified; it is determined by the order of
3286 elements in the input stream. Most objects have the associated
3287 note head as their parent.
3289 The values of the @code{side-axis} and @code{direction} properties
3290 determine where the object is to be placed, as follows:
3292 @c TODO add an example of each to the table
3294 @multitable @columnfractions .3 .3 .3
3295 @headitem @code{side-axis} @tab @code{direction} @tab
3296 @headitem property @tab property @tab Placement
3298 @item @code{0} @tab @code{-1} @tab left
3299 @item @code{0} @tab @code{1} @tab right
3300 @item @code{1} @tab @code{-1} @tab below
3301 @item @code{1} @tab @code{1} @tab above
3305 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
3306 the procedure @code{ly:side-position-interface::x-aligned-side}.
3307 This procedure will return the correct value of @code{X-offset} to
3308 place the object to the left or right side of the parent according
3309 to value of @code{direction}.
3311 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
3312 the procedure @code{ly:side-position-interface::y-aligned-side}.
3313 This procedure will return the correct value of @code{Y-offset} to
3314 place the object to the top or bottom of the parent according
3315 to value of @code{direction}.
3317 @c TODO Add examples
3319 @node Using the self-alignment-interface
3320 @unnumberedsubsubsec Using the @code{self-alignment-interface}
3322 @emph{Self-aligning objects horizontally}
3324 The horizontal alignment of an object which supports the
3325 @code{self-alignment-interface} is controlled by the value of
3326 the @code{self-alignment-X} property, provided the object's
3327 @code{X-offset} property is set to
3328 @code{ly:self-alignment-interface::x-aligned-on-self}.
3329 @code{self-alignment-X} may be given any
3330 real value, in units of half the total X extent of the
3331 object. Negative values move the object to the right, positive
3332 to the left. A value of @code{0} centers the object on the
3333 reference point of its parent, a value of @w{@code{-1}} aligns the
3334 left edge of the object on the reference point of its parent,
3335 and a value of @code{1} aligns the right edge of the object on the
3336 reference point of its parent. The symbols @code{LEFT},
3337 @code{CENTER}, and @code{RIGHT} may be used instead of the values
3338 @w{@code{-1}}, @code{0}, and @code{1}, respectively.
3340 Normally the @code{\override} command would be used to modify the
3341 value of @code{self-alignment-X}, but the @code{\tweak} command
3342 can be used to separately align several annotations on a single
3345 @lilypond[quote,verbatim,relative=1]
3347 -\tweak #'self-alignment-X #-1
3349 -\tweak #'self-alignment-X #0
3351 -\tweak #'self-alignment-X #RIGHT
3353 -\tweak #'self-alignment-X #-2.5
3354 ^"aligned further to the right"
3357 @emph{Self-aligning objects vertically}
3359 Objects may be aligned vertically in an analogous way to aligning
3360 them horizontally if the @code{Y-offset} property is set to
3361 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
3362 other mechanisms are often involved in vertical alignment: the
3363 value of @code{Y-offset} is just one variable taken into account.
3364 This may make adjusting the value of some objects tricky.
3365 The units are just half the vertical extent of the object, which
3366 is usually quite small, so quite large numbers may be required.
3367 A value of @w{@code{-1}} aligns the lower edge of the object with
3368 the reference point of the parent object, a value of @code{0}
3369 aligns the center of the object with the reference point of the
3370 parent, and a value of @code{1} aligns the top edge of the object
3371 with the reference point of the parent. The symbols @code{DOWN},
3372 @code{CENTER}, and @code{UP} may be substituted for @w{@code{-1}},
3373 @code{0}, and @code{1}, respectively.
3375 @emph{Self-aligning objects in both directions}
3377 By setting both @code{X-offset} and @code{Y-offset}, an object may
3378 be aligned in both directions simultaneously.
3380 The following example shows how to adjust a fingering mark so
3381 that it nestles close to the note head.
3383 @lilypond[quote,verbatim,relative=2]
3385 -\tweak #'self-alignment-X #0.5 % move horizontally left
3386 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
3387 -\tweak #'self-alignment-Y #-1 % move vertically up
3392 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
3394 @c Cannot document as they do not seem to operate consistently on all objects -td
3395 @c TODO investigate further
3397 The @code{aligned-on-parent} procedures are used in the same way
3398 as the @code{aligned-on-self} procedures, they difference being
3399 that they permit an object to be aligned with the @emph{edges} of
3400 the parent rather than the parent's reference point. The following
3401 example shows the difference:
3405 @lilypond[verbatim,quote]
3411 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
3413 @c Cannot document as they do not seem to operate consistently on all objects -td
3414 @c TODO investigate further
3418 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
3420 @node Using the break-alignable-interface
3421 @unnumberedsubsubsec Using the @code{break-alignable-interface}
3423 @cindex align to objects
3424 @cindex break-align-symbols
3426 Rehearsal marks and bar numbers may be aligned with notation
3427 objects other than bar lines. These objects include @code{ambitus},
3428 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
3429 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
3430 @code{time-signature}.
3432 By default, rehearsal marks and bar numbers will be horizontally
3433 centered above the object:
3435 @lilypond[verbatim,quote,relative=1]
3436 % The rehearsal mark will be centered above the Clef
3437 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
3442 % The rehearsal mark will be centered above the Time Signature
3443 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
3449 % The rehearsal mark will be centered above the Breath Mark
3450 \override Score.RehearsalMark #'break-align-symbols = #'(breathing-sign)
3459 A list of possible target alignment objects may be specified. If
3460 some of the objects are invisible at that point due to the setting
3461 of @code{break-visibility} or the explicit visibility settings for
3462 keys and clefs, the rehearsal mark or bar number is aligned to the
3463 first object in the list which is visible. If no objects in the
3464 list are visible the object is aligned to the bar line. If the bar
3465 line is invisible the object is aligned to the place where the bar
3468 @lilypond[verbatim,quote,relative=1]
3469 % The rehearsal mark will be centered above the Key Signature
3470 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3475 % The rehearsal mark will be centered above the Clef
3476 \set Staff.explicitKeySignatureVisibility = #all-invisible
3477 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3482 % The rehearsal mark will be centered above the Bar Line
3483 \set Staff.explicitKeySignatureVisibility = #all-invisible
3484 \set Staff.explicitClefVisibility = #all-invisible
3485 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
3492 The alignment of the rehearsal mark relative to the notation object
3493 can be changed, as shown in the following example. In a score with
3494 multiple staves, this setting should be done for all the staves.
3496 @lilypond[verbatim,quote,relative=1]
3497 % The RehearsalMark will be centered above the Key Signature
3498 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3504 % The RehearsalMark will be aligned with the left edge of the Key Signature
3505 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3509 % The RehearsalMark will be aligned with the right edge of the Key Signature
3510 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3516 The rehearsal mark can also be offset to the right or left of the left
3517 edge by an arbitrary amount. The units are staff-spaces:
3519 @lilypond[verbatim,quote,relative=1]
3520 % The RehearsalMark will be aligned with the left edge of the Key Signature
3521 % and then shifted right by 3.5 staff-spaces
3522 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3523 \once \override Score.KeySignature #'break-align-anchor = #3.5
3527 % The RehearsalMark will be aligned with the left edge of the Key Signature
3528 % and then shifted left by 2 staff-spaces
3529 \once \override Score.KeySignature #'break-align-anchor = #-2
3536 @node Vertical grouping of grobs
3537 @subsection Vertical grouping of grobs
3539 @c TODO Expand this section
3541 The VerticalAlignment and VerticalAxisGroup grobs work together.
3542 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3543 etc. VerticalAlignment then vertically aligns the different grobs
3544 grouped together by VerticalAxisGroup. There is usually only one
3545 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3549 @node Modifying stencils
3550 @subsection Modifying stencils
3552 All layout objects have a @code{stencil} property which is part of
3553 the @code{grob-interface}. By default, this property is usually
3554 set to a function specific to the object that is tailor-made to
3555 render the symbol which represents it in the output. For example,
3556 the standard setting for the @code{stencil} property of the
3557 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3559 The standard symbol for any object can be replaced by modifying the
3560 @code{stencil} property to reference a different, specially-written,
3561 procedure. This requires a high level of knowledge of the internal
3562 workings of LilyPond, but there is an easier way which can often
3563 produce adequate results.
3565 This is to set the @code{stencil} property to the procedure which
3566 prints text -- @code{ly:text-interface::print} -- and to add a
3567 @code{text} property to the object which is set to contain the
3568 markup text which produces the required symbol. Due to the
3569 flexibility of markup, much can be achieved -- see in particular
3570 @ref{Graphic notation inside markup}.
3572 The following example demonstrates this by changing the note head
3573 symbol to a cross within a circle.
3575 @lilypond[verbatim,quote]
3577 \once \override NoteHead #'stencil = #ly:text-interface::print
3578 \once \override NoteHead #'text = \markup {
3580 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3581 \musicglyph #"noteheads.s2cross"
3589 Any of the glyphs in the feta Font can be supplied to the
3590 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3592 @c TODO Add inserting eps files or ref to later
3594 @c TODO Add inserting Postscript or ref to later
3599 @ref{Graphic notation inside markup},
3600 @ref{Formatting text},
3601 @ref{Text markup commands},
3602 @ref{The Feta font}.
3605 @node Modifying shapes
3606 @subsection Modifying shapes
3609 * Modifying ties and slurs::
3612 @node Modifying ties and slurs
3613 @unnumberedsubsubsec Modifying ties and slurs
3615 @cindex slurs, modifying
3616 @cindex ties, modifying
3617 @cindex Bézier curves, control points
3618 @cindex control points, Bézier curves
3620 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3621 curves. If the shape of the tie or slur which is calculated
3622 automatically is not optimum, the shape may be modified manually by
3623 explicitly specifying the four control points required to define
3624 a third-order Bézier curve.
3626 Third-order or cubic Bézier curves are defined by four control
3627 points. The first and fourth control points are precisely the
3628 starting and ending points of the curve. The intermediate two
3629 control points define the shape. Animations showing how the curve
3630 is drawn can be found on the web, but the following description
3631 may be helpful. The curve starts from the first control point
3632 heading directly towards the second, gradually bending over to
3633 head towards the third and continuing to bend over to head towards
3634 the fourth, arriving there travelling directly from the third
3635 control point. The curve is entirely contained in the
3636 quadrilateral defined by the four control points.
3638 Here is an example of a case where the tie is not optimum, and
3639 where @code{\tieDown} would not help.
3641 @lilypond[verbatim,quote,relative=1]
3645 { r4 <g c,> <g c,> <g c,> }
3649 One way of improving this tie is to manually modify its control
3652 The coordinates of the Bézier control points are specified in units
3653 of staff-spaces. The X@tie{}coordinate is relative to the reference
3654 point of the note to which the tie or slur is attached, and the
3655 Y@tie{}coordinate is relative to the staff center line. The
3656 coordinates are entered as a list of four pairs of decimal numbers
3657 (reals). One approach is to estimate the coordinates of the two
3658 end points, and then guess the two intermediate points. The optimum
3659 values are then found by trial and error.
3661 It is useful to remember that a symmetric curve requires symmetric
3662 control points, and that Bézier curves have the useful property that
3663 transformations of the curve such as translation, rotation and
3664 scaling can be achieved by applying the same transformation to the
3665 curve's control points.
3667 For the example above the following override gives a satisfactory
3668 tie. Note the placement -- it has to be immediately before the note
3669 to which the start of the tie (or slur) is attached.
3671 @lilypond[verbatim,quote,relative=1]
3675 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3679 { r4 <g c,> <g c,> <g c,> }
3684 It is not possible to modify shapes of ties or slurs by changing
3685 the @code{control-points} property if there are multiple ties or slurs
3686 at the same musical moment -- the @code{\tweak} command will also not
3687 work in this case. However, the @code{tie-configuration} property of
3688 @code{TieColumn} can be overridden to set start line and direction as
3692 Internals Reference:
3693 @rinternals{TieColumn}.
3695 @cindex Scheme, pure containers
3696 @cindex Scheme, unpure containers
3697 @cindex pure containers, Scheme
3698 @cindex unpure containers, Scheme
3699 @cindex horizontal spacing, overriding
3701 @node Unpure-pure containers
3702 @subsection Unpure-pure containers
3704 Unpure-pure containers are useful for overriding @emph{Y-axis} spacing
3705 calculations - specifically @code{Y-offset} and @code{Y-extent} - with a
3706 Scheme function instead of a literal (i.e. a number or pair).
3708 For certain grobs, the @code{Y-extent} is based on the @code{stencil}
3709 property, overriding the stencil property of one of these will
3710 require an additional @code{Y-extent} override with an unpure-pure
3711 container. When a function overrides a @code{Y-offset} and/or
3712 @code{Y-extent} it is assumed that this will trigger line breaking
3713 calculations too early during compilation. So the function is not
3714 evaluated at all (usually returning a value of @samp{0} or
3715 @samp{'(0 . 0)}) which can result in collisions. A @q{pure} function
3716 will not affect properties, objects or grob suicides and therefore will
3717 always have its Y-axis-related evaluated correctly.
3719 Currently, there are about thirty functions that are already considered
3720 @q{pure} and Unpure-pure containers are a way to set functions not on
3721 this list as @q{pure}. The @q{pure} function is evaluated @emph{before}
3722 any line-breaking and so the horizontal spacing can be adjusted
3723 @q{in time}. The @q{unpure} function is then evaluated @emph{after}
3726 @warning{As it is difficult to always know which functions are on this
3727 list we recommend that any @q{pure} functions you create do not use
3728 @code{Beam} or @code{VerticalAlignment} grobs.}
3730 An unpure-pure container is constructed as follows;
3732 @code{(ly:make-unpure-pure-container f0 f1)}
3734 where @code{f0} is a function taking @var{n} arguments (@var{n >= 1})
3735 and the first argument must always be the grob. This is the function
3736 that gives the actual result. @var{f1} is the function being labeled
3737 as @q{pure} that takes @var{n + 2} arguments. Again, the first argument
3738 must always still be the grob but the second and third are @q{start}
3739 and @q{end} arguments.
3741 @var{start} and @var{end} are, for all intents and purposes, dummy
3742 values that only matter for @code{Spanners} (i.e @code{Hairpin} or
3743 @code{Beam}), that can return different height estimations based on a
3744 starting and ending column.
3746 The rest are the other arguments to the first function (which
3747 may be none if @var{n = 1}).
3749 The results of the second function are used as an approximation of the
3750 value needed which is then used by the first function to get the real
3751 value which is then used for fine-tuning much later during the spacing
3754 @lilypond[verbatim,quote,ragged-right]
3755 #(define (square-line-circle-space grob)
3756 (let* ((pitch (ly:event-property (ly:grob-property grob 'cause) 'pitch))
3757 (notename (ly:pitch-notename pitch)))
3758 (if (= 0 (modulo notename 2))
3759 (make-circle-stencil 0.5 0.0 #t)
3760 (make-filled-box-stencil '(0 . 1.0)
3763 squareLineCircleSpace = {
3764 \override NoteHead #'stencil = #square-line-circle-space
3767 smartSquareLineCircleSpace = {
3768 \squareLineCircleSpace
3769 \override NoteHead #'Y-extent =
3770 #(ly:make-unpure-pure-container
3771 ly:grob::stencil-height
3772 (lambda (grob start end) (ly:grob::stencil-height grob)))
3775 \new Voice \with { \remove "Stem_engraver" }
3777 \squareLineCircleSpace
3779 \smartSquareLineCircleSpace
3784 In the first measure, without the unpure-pure container, the spacing
3785 engine does not know the width of the note head and lets it collide with
3786 the accidentals. In the second measure, with unpure-pure containers,
3787 the spacing engine knows the width of the note heads and avoids the
3788 collision by lengthening the line accordingly.
3790 Usually for simple calculations nearly-identical functions for both the
3791 @q{unpure} and @q{pure} parts can be used, by only changing the number
3792 of arguments passed to, and the scope of, the function.
3794 @warning{If a function is labeled as @q{pure} and it turns out not to
3795 be, the results can be unexpected.}
3798 @node Using music functions
3799 @section Using music functions
3801 @c TODO -- add @seealso, etc. to these subsections
3803 Where tweaks need to be reused with different music expressions,
3804 it is often convenient to make the tweak part of a @emph{music
3805 function}. In this section, we discuss only @emph{substitution}
3806 functions, where the object is to substitute a variable into a
3807 piece of LilyPond input code. Other more complex functions are
3808 described in @rextend{Music functions}.
3811 * Substitution function syntax::
3812 * Substitution function examples::
3815 @node Substitution function syntax
3816 @subsection Substitution function syntax
3818 Making a function that substitutes a variable into LilyPond
3819 code is easy. The general form of these functions is
3823 #(define-music-function
3824 (parser location @var{arg1} @var{arg2} @dots{})
3825 (@var{type1?} @var{type2?} @dots{})
3827 @var{@dots{}music@dots{}}
3834 @multitable @columnfractions .33 .66
3835 @item @code{@var{argN}}
3836 @tab @var{n}th argument
3838 @item @code{@var{typeN?}}
3839 @tab a scheme @emph{type predicate} for which @code{@var{argN}}
3840 must return @code{#t}.
3842 @item @code{@var{@dots{}music@dots{}}}
3843 @tab normal LilyPond input, using @code{$} (in places where only
3844 Lilypond constructs are allowed) or @code{#} (to use it as a Scheme
3845 value or music function argument) to reference arguments
3849 The @code{parser} and @code{location} arguments are mandatory, and
3850 are used in some advanced situations as described in the
3851 @q{Extending} manual (see @rextend{Music functions}). For
3852 substitution functions, just be sure to include them.
3854 The list of type predicates is also required. Some of the most
3855 common type predicates used in music functions are:
3859 cheap-list? @emph{(use instead of }@q{list?}@emph{ for faster processing)}
3871 For a list of available type predicates, see
3872 @ref{Predefined type predicates}. User-defined type predicates
3879 @ref{Predefined type predicates}.
3882 @rextend{Music functions}.
3885 @file{lily/music-scheme.cc},
3887 @file{scm/lily.scm}.
3890 @node Substitution function examples
3891 @subsection Substitution function examples
3893 This section introduces some substitution function examples.
3894 These are not intended to be exhaustive, but rather to demonstrate
3895 some of the possibilities of simple substitution functions.
3897 In the first example, a function is defined that simplifies
3898 setting the padding of a TextScript:
3900 @lilypond[quote,verbatim,ragged-right]
3902 #(define-music-function
3903 (parser location padding)
3906 \once \override TextScript #'padding = #padding
3910 c4^"piu mosso" b a b
3912 c4^"piu mosso" d e f
3914 c4^"piu mosso" fis a g
3918 In addition to numbers, we can use music expressions such
3919 as notes for arguments to music functions:
3921 @c TODO: use a better example (the music argument is redundant).
3923 @lilypond[quote,verbatim,ragged-right]
3925 #(define-music-function
3926 (parser location note)
3929 \once \override Voice.NoteHead #'stencil =
3930 #ly:text-interface::print
3931 \once \override Voice.NoteHead #'text =
3932 \markup \musicglyph #"custodes.mensural.u0"
3933 \once \override Voice.Stem #'stencil = ##f
3937 \relative c' { c4 d e f \custosNote g }
3940 Substitution functions with multiple arguments can be defined:
3942 @lilypond[quote,verbatim,ragged-right]
3944 #(define-music-function
3945 (parser location padding tempotext)
3948 \once \override Score.MetronomeMark #'padding = #padding
3949 \tempo \markup { \bold #tempotext }
3953 \tempo \markup { "Low tempo" }
3955 \tempoPadded #4.0 #"High tempo"
3960 @c TODO: add appropriate @@ref's here.