1 @c -*- coding: utf-8; mode: texinfo; -*-
2 @c This file is part of lilypond.tely
4 Translation of GIT committish: FILL-IN-HEAD-COMMITTISH
6 When revising a translation, copy the HEAD committish of the
7 version that you are working on. See TRANSLATION for details.
12 @node Changing defaults
13 @chapter Changing defaults
15 The purpose of LilyPond's design is to provide the finest quality
16 output by default. Nevertheless, it may happen that you need to
17 change this default layout. The layout is controlled through a large
18 number of @q{knobs and switches} collectively called @q{properties}.
19 A tutorial introduction to accessing and modifying these properties
20 can be found in the Learning Manual, see @rlearning{Tweaking output}.
21 This should be read first. This chapter covers similar ground, but
22 in a style more appropriate to a reference manual.
24 @cindex Internals Reference
26 The definitive description of the controls available for tuning can
27 be found in a separate document: @rinternalsnamed{Top,the Internals
28 Reference}. That manual lists all the variables, functions and
29 options available in LilyPond. It is written as a HTML document,
31 @c leave the @uref as one long line.
32 @uref{http://@/lilypond@/.org/@/doc/@/stable/@/Documentation/@/user/@/lilypond@/-internals/,on@/-line},
33 and is also included with the LilyPond documentation package.
35 Internally, LilyPond uses Scheme (a LISP dialect) to provide
36 infrastructure. Overriding layout decisions in effect accesses the
37 program internals, which requires Scheme input. Scheme elements are
38 introduced in a @code{.ly} file with the hash mark
39 @code{#}.@footnote{@rlearning{Scheme tutorial}, contains a short tutorial
40 on entering numbers, lists, strings, and symbols in Scheme.}
44 * Interpretation contexts::
45 * Explaining the Internals Reference::
46 * Modifying properties::
47 * Useful concepts and properties::
52 @node Interpretation contexts
53 @section Interpretation contexts
55 This section describes what contexts are, and how to modify them.
58 * Contexts explained::
60 * Modifying context plug-ins::
61 * Changing context default settings::
62 * Defining new contexts::
69 @rlearning{Contexts and engravers}.
72 @file{ly/@/engraver@/-init@/.ly},
73 @file{ly/@/performer@/-init@/.ly}.
76 @rlsr{Contexts and engravers}.
79 @rinternals{Contexts},
80 @rinternals{Engravers and performers}.
83 @node Contexts explained
84 @subsection Contexts explained
87 @c TODO Rethink and rewrite
89 >> > > - list of contexts: my *danger unmaintainable*
90 >> > > alarm just went off. I'm
92 I knew it would... And leaving out some of them is perfectly fine
94 I do think that a list like this, with the main contexts and a
96 description of what they do (perhaps also with a note about what
98 behavior is associated with each of them, but this may be
100 should be there, and then we could simply list the remaining ones
102 further explanation and with links to the IR.
105 @c TODO Improve layout, order and consistency of wording -td
107 @c TODO Add introduction which explains contexts in generality -td
109 @c TODO Describe propagation of property values -td
111 Contexts are arranged heirarchically:
114 * Score - the master of all contexts::
115 * Top-level contexts - staff containers::
116 * Intermediate-level contexts - staves::
117 * Bottom-level contexts - voices::
120 @node Score - the master of all contexts
121 @unnumberedsubsubsec Score - the master of all contexts
123 This is the top level notation context. No other context can
124 contain a Score context. By default the Score context handles
125 the administration of time signatures and makes sure that items
126 such as clefs, time signatures, and key-signatures are aligned
129 A Score context is instantiated implicitly when a
130 @code{\score @{@dots{}@}} or @code{\layout @{@dots{}@}} block is
131 processed, or explicitly when a @code{\new Score} command is
134 @node Top-level contexts - staff containers
135 @unnumberedsubsubsec Top-level contexts - staff containers
137 @strong{@emph{StaffGroup}}
139 Groups staves while adding a bracket on the left side, grouping
140 the staves together. The bar lines of the contained staves are
141 connected vertically. StaffGroup only consists of a collection
142 of staves, with a bracket in front and spanning bar lines.
144 @strong{@emph{ChoirStaff}}
146 Identical to StaffGroup except that the bar lines of the contained
147 staves are not connected vertically.
149 @strong{@emph{GrandStaff}}
151 A group of staves, with a brace on the left side, grouping
152 the staves together. The bar lines of the contained staves are
153 connected vertically.
155 @strong{@emph{PianoStaff}}
157 @c TODO No longer correct? Check. -td
158 Just like GrandStaff but with a forced distance between the
159 staves, so cross staff beaming and slurring can be used.
162 @strong{@emph{InnerStaffGroup}}
166 @strong{@emph{InnerChoirStaff}}
172 @node Intermediate-level contexts - staves
173 @unnumberedsubsubsec Intermediate-level contexts - staves
175 @strong{@emph{Staff}}
177 Handles clefs, bar lines, keys, accidentals. It can contain
180 @strong{@emph{RhythmicStaff}}
182 Like Staff but for printing rhythms. Pitches are ignored;
183 the notes are printed on one line.
185 @strong{@emph{TabStaff}}
187 Context for generating tablature. By default lays the music
188 expression out as a guitar tablature, printed on six lines.
190 @strong{@emph{DrumStaff}}
192 Handles typesetting for percussion. Can contain DrumVoice
194 @strong{@emph{VaticanaStaff}}
196 Same as Staff, except that it is designed for typesetting
197 a piece in gregorian style.
199 @strong{@emph{MensuralStaff}}
201 Same as Staff, except that it is designed for typesetting
202 a piece in mensural style.
204 @node Bottom-level contexts - voices
205 @unnumberedsubsubsec Bottom-level contexts - voices
207 Voice-level contexts initialise certain properties and start
208 appropriate engravers. Being bottom-level contexts, they cannot
209 contain other contexts.
211 @strong{@emph{Voice}}
213 Corresponds to a voice on a staff. This context handles the
214 conversion of dynamic signs, stems, beams, super- and sub-scripts,
215 slurs, ties, and rests. You have to instantiate this explicitly
216 if you require multiple voices on the same staff.
218 @strong{@emph{VaticanaVoice}}
220 Same as Voice, except that it is designed for typesetting a piece
223 @strong{@emph{MensuralVoice}}
225 Same as Voice, with modifications for typesetting a piece in
228 @strong{@emph{Lyrics}}
230 Corresponds to a voice with lyrics. Handles the printing of a
231 single line of lyrics.
233 @strong{@emph{DrumVoice}}
235 The voice context used in a percussion staff.
237 @strong{@emph{FiguredBass}}
239 The context in which BassFigure objects are created from
240 input entered in @code{\figuremode} mode.
242 @strong{@emph{TabVoice}}
244 The voice context used within a TabStaff context. Usually left to
245 be created implicitly.
247 @strong{@emph{ChordNames}}
249 Typesets chord names.
254 Then the following, which I don't know what to do with:
256 * GregorianTranscriptionVoice
257 * GregorianTranscriptionStaff
260 Engraves fretboards from chords. Not easy... Not
262 There is now some documentation on FretBoards in the NR, under
263 instrument-specific notation -- cds.
267 * CueVoice Not documented
269 Hard coded entry point for LilyPond. Cannot be tuned.
271 Silently discards all musical information given to this
276 @node Creating contexts
277 @subsection Creating contexts
279 @c TODO \new Score and \score
280 @c TODO more complete descriptions rather than learning style
282 For scores with only one voice and one staff, contexts are
283 created automatically. For more complex scores, it is necessary to
284 create them by hand. There are three commands that do this.
289 The easiest command is @code{\new}, and it also the quickest to type.
290 It is prepended to a music expression, for example
294 @cindex Context, creating
297 \new @var{type} @var{music expression}
301 where @var{type} is a context name (like @code{Staff} or
302 @code{Voice}). This command creates a new context, and starts
303 interpreting the @var{music expression} with that.
305 A practical application of @code{\new} is a score with many
306 staves. Each part that should be on its own staff, is preceded with
309 @lilypond[quote,verbatim,relative=2,ragged-right,fragment]
316 The @code{\new} command may also give a name to the context,
319 \new @var{type} = @var{id} @var{music}
321 However, this user specified name is only used if there is no other
322 context already earlier with the same name.
328 Like @code{\new}, the @code{\context} command also directs a music
329 expression to a context object, but gives the context an explicit name. The
333 \context @var{type} = @var{id} @var{music}
336 This form will search for an existing context of type @var{type}
337 called @var{id}. If that context does not exist yet, a new
338 context with the specified name is created. This is useful if
339 the context is referred to later on. For example, when
340 setting lyrics the melody is in a named context
343 \context Voice = "@b{tenor}" @var{music}
347 so the texts can be properly aligned to its notes,
350 \new Lyrics \lyricsto "@b{tenor}" @var{lyrics}
355 Another possible use of named contexts is funneling two different
356 music expressions into one context. In the following example,
357 articulations and notes are entered separately,
361 arts = @{ s4-. s4-> @}
364 They are combined by sending both to the same @code{Voice} context,
368 \new Staff \context Voice = "A" \music
369 \context Voice = "A" \arts
372 @lilypond[quote,ragged-right]
376 \new Staff \context Voice = "A" \music
377 \context Voice = "A" \arts
381 With this mechanism, it is possible to define an Urtext (original
382 edition), with the option to put several distinct articulations on the
385 @cindex creating contexts
388 The third command for creating contexts is
390 \context @var{type} @var{music}
395 This is similar to @code{\context} with @code{= @var{id}}, but matches
396 any context of type @var{type}, regardless of its given name.
398 This variant is used with music expressions that can be interpreted at
399 several levels. For example, the @code{\applyOutput} command (see
400 @ref{Running a function on all layout objects}). Without an explicit
401 @code{\context}, it is usually applied to @code{Voice}
404 \applyOutput #'@var{context} #@var{function} % apply to Voice
407 To have it interpreted at the @code{Score} or @code{Staff} level use
411 \applyOutput #'Score #@var{function}
412 \applyOutput #'Staff #@var{function}
418 @node Modifying context plug-ins
419 @subsection Modifying context plug-ins
421 @c TODO Should this be Modifying engravers or Modifying contexts?
423 Notation contexts (like @code{Score} and @code{Staff}) not only
425 they also contain plug-ins called @q{engravers} that create notation
426 elements. For example, the @code{Voice} context contains a
427 @code{Note_head_engraver} and the @code{Staff} context contains a
428 @code{Key_signature_engraver}.
430 For a full a description of each plug-in, see
432 @rinternals{Engravers and Performers}.
435 Internals Reference @expansion{} Translation @expansion{} Engravers.
437 Every context described in
439 @rinternals{Contexts}
442 Internals Reference @expansion{} Translation @expansion{} Context.
444 lists the engravers used for that context.
447 It can be useful to shuffle around these plug-ins. This is done by
448 starting a new context with @code{\new} or @code{\context}, and
454 \new @var{context} \with @{
467 where the @dots{} should be the name of an engraver. Here is a simple
468 example which removes @code{Time_signature_engraver} and
469 @code{Clef_engraver} from a @code{Staff} context,
471 @lilypond[quote,relative=1,verbatim,fragment]
477 \remove "Time_signature_engraver"
478 \remove "Clef_engraver"
485 In the second staff there are no time signature or clef symbols. This
486 is a rather crude method of making objects disappear since it will affect
487 the entire staff. This method also influences the spacing, which may or
488 may not be desirable. More sophisticated methods of blanking objects
489 are shown in @rlearning{Visibility and color of objects}.
491 The next example shows a practical application. Bar lines and time
492 signatures are normally synchronized across the score. This is done
493 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
494 This plug-in keeps an administration of time signature, location
495 within the measure, etc. By moving these engraver from @code{Score} to
496 @code{Staff} context, we can have a score where each staff has its own
499 @cindex polymetric scores
500 @cindex Time signatures, multiple
502 @lilypond[quote,relative=1,ragged-right,verbatim,fragment]
504 \remove "Timing_translator"
505 \remove "Default_bar_line_engraver"
508 \consists "Timing_translator"
509 \consists "Default_bar_line_engraver"
515 \consists "Timing_translator"
516 \consists "Default_bar_line_engraver"
526 Usually the order in which the engravers are specified
527 does not matter, but in a few special cases the order
528 is important, for example where one engraver writes
529 a property and another reads it, or where one engraver
530 creates a grob and another must process it. The order in
531 which the engravers are specified is the order in which
532 they are called to carry out their processing.
534 The following orderings are important: the
535 @code{Bar_engraver} must normally be first, and
536 the @code{New_fingering_engraver} must come before
537 the @code{Script_column_engraver}. There may be others
538 with ordering dependencies.
540 @node Changing context default settings
541 @subsection Changing context default settings
543 The adjustments of the previous subsections (
544 @ref{The set command}, @ref{Modifying context plug-ins}, and
545 @ref{Overview of modifying properties}) can also be entered
546 separately from the music in the @code{\layout} block,
555 \override Stem #'thickness = #4.0
556 \remove "Time_signature_engraver"
561 The @code{\Staff} command brings in the existing definition of the
562 staff context so that it can be modified.
567 \override Stem #'thickness = #4.0
568 \remove "Time_signature_engraver"
572 affect all staves in the score. Other contexts can be modified
575 The @code{\set} keyword is optional within the @code{\layout} block, so
591 It is not possible to collect context changes in a variable and apply
592 them to a @code{\context} definition by referring to that variable.
594 The @code{\RemoveEmptyStaffContext} will overwrite your current
595 @code{\Staff} settings. If you wish to change the defaults for a
596 staff which uses @code{\RemoveEmptyStaffContext}, you must do so
597 after calling @code{\RemoveEmptyStaffContext}, ie
602 \RemoveEmptyStaffContext
604 \override Stem #'thickness = #4.0
609 @c TODO: add \with in here.
613 @node Defining new contexts
614 @subsection Defining new contexts
616 Specific contexts, like @code{Staff} and @code{Voice}, are made of
617 simple building blocks. It is possible to create new types of
618 contexts with different combinations of engraver plug-ins.
620 The next example shows how to build a different type of
621 @code{Voice} context from scratch. It will be similar to
622 @code{Voice}, but only prints centered slash note heads. It can be used
623 to indicate improvisation in jazz pieces,
625 @lilypond[quote,ragged-right]
628 \type "Engraver_group"
629 \consists "Note_heads_engraver"
630 \consists "Text_engraver"
631 \consists Pitch_squash_engraver
632 squashedPosition = #0
633 \override NoteHead #'style = #'slash
634 \override Stem #'transparent = ##t
638 \accepts "ImproVoice"
642 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
643 c4 c^"undress" c_"while playing :)" c }
649 These settings are defined within a @code{\context} block inside a
650 @code{\layout} block,
660 In the following discussion, the example input shown should go in place
661 of the @dots{} in the previous fragment.
663 First it is necessary to define a name for the new context:
669 Since it is similar to the @code{Voice}, we want commands that work
670 on (existing) @code{Voice}s to remain working. This is achieved by
671 giving the new context an alias @code{Voice},
677 The context will print notes and instructive texts, so we need to add
678 the engravers which provide this functionality,
681 \consists Note_heads_engraver
682 \consists Text_engraver
685 but we only need this on the center line,
688 \consists Pitch_squash_engraver
689 squashedPosition = #0
692 The @rinternals{Pitch_squash_engraver} modifies note heads (created
693 by @rinternals{Note_heads_engraver}) and sets their vertical
694 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
697 The notes look like a slash, and have no stem,
700 \override NoteHead #'style = #'slash
701 \override Stem #'transparent = ##t
704 All these plug-ins have to cooperate, and this is achieved with a
705 special plug-in, which must be marked with the keyword @code{\type}.
706 This should always be @code{Engraver_group}.
709 \type "Engraver_group"
717 \type "Engraver_group"
718 \consists "Note_heads_engraver"
719 \consists "Text_engraver"
720 \consists Pitch_squash_engraver
721 squashedPosition = #0
722 \override NoteHead #'style = #'slash
723 \override Stem #'transparent = ##t
729 Contexts form hierarchies. We want to hang the @code{ImproVoice}
730 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
731 modify the @code{Staff} definition with the @code{\accepts}
742 The opposite of @code{\accepts} is @code{\denies},
743 which is sometimes needed when reusing existing context definitions.
745 Putting both into a @code{\layout} block, like
755 \accepts "ImproVoice"
760 Then the output at the start of this subsection can be entered as
768 c c_"while playing :)"
775 @node Aligning contexts
776 @subsection Aligning contexts
778 New contexts may be aligned above or below existing contexts. This
779 could be useful in setting up a vocal staff (@rlearning{Vocal ensembles}) and
782 @c TODO Better example needed. Ref LM, and expand on it.
785 @findex alignAboveContext
786 @findex alignBelowContext
788 @lilypond[quote,ragged-right]
791 \relative c' \new Staff = "main" {
794 \new Staff \with {alignAboveContext=main} \ossia
802 @node Explaining the Internals Reference
803 @section Explaining the Internals Reference
807 * Navigating the program reference::
808 * Layout interfaces::
809 * Determining the grob property::
810 * Naming conventions::
813 @node Navigating the program reference
814 @subsection Navigating the program reference
816 @c TODO remove this (it's in the LM)
817 @c Replace with more factual directions
819 Suppose we want to move the fingering indication in the fragment
822 @lilypond[quote,fragment,relative=2,verbatim]
828 If you visit the documentation on fingering instructions (in
829 @ref{Fingering instructions}), you will notice:
834 Internals Reference: @rinternals{Fingering}.
839 @c outdated info; probably will delete.
841 This fragment points to two parts of the program reference: a page
842 on @code{FingeringEvent} and one on @code{Fingering}.
844 The page on @code{FingeringEvent} describes the properties of the music
845 expression for the input @code{-2}. The page contains many links
846 forward. For example, it says
849 Accepted by: @rinternals{Fingering_engraver},
853 That link brings us to the documentation for the Engraver, the
857 This engraver creates the following layout objects: @rinternals{Fingering}.
860 In other words, once the @code{FingeringEvent}s are interpreted, the
861 @code{Fingering_engraver} plug-in will process them.
865 @c I can't figure out what this is supposed to mean. -gp
867 The @code{Fingering_engraver} is also listed to create
868 @rinternals{Fingering} objects,
870 @c old info? it doesn't make any sense to me with our current docs.
872 second bit of information listed under @b{See also} in the Notation
877 The programmer's reference is available as an HTML document. It is
878 highly recommended that you read it in HTML form, either online or
879 by downloading the HTML documentation. This section will be much more
880 difficult to understand if you are using the
884 Follow the link to @rinternals{Fingering}. At the top of the
888 Fingering objects are created by: @rinternals{Fingering_engraver} and
889 @rinternals{New_fingering_engraver}.
892 By following related links inside the program reference, we can follow the
893 flow of information within the program:
897 @item @rinternals{Fingering}:
898 @rinternals{Fingering} objects are created by:
899 @rinternals{Fingering_engraver}
901 @item @rinternals{Fingering_engraver}:
902 Music types accepted: @rinternals{fingering-event}
904 @item @rinternals{fingering-event}:
905 Music event type @code{fingering-event} is in Music expressions named
906 @rinternals{FingeringEvent}
909 This path goes against the flow of information in the program: it
910 starts from the output, and ends at the input event. You could
911 also start at an input event, and read with the flow of
912 information, eventually ending up at the output object(s).
914 The program reference can also be browsed like a normal document. It
917 @rinternals{Music definitions},
920 @code{Music definitions}
922 on @rinternals{Translation}, and the @rinternals{Backend}. Every
923 chapter lists all the definitions used and all properties that may be
927 @node Layout interfaces
928 @subsection Layout interfaces
930 @cindex interface, layout
931 @cindex layout interface
934 The HTML page that we found in the previous section describes the
935 layout object called @rinternals{Fingering}. Such an object is a
936 symbol within the score. It has properties that store numbers (like
937 thicknesses and directions), but also pointers to related objects. A
938 layout object is also called a @emph{Grob}, which is short for Graphical
939 Object. For more details about Grobs, see @rinternals{grob-interface}.
941 The page for @code{Fingering} lists the definitions for the
942 @code{Fingering} object. For example, the page says
945 @code{padding} (dimension, in staff space):
951 which means that the number will be kept at a distance of at least 0.5
955 Each layout object may have several functions as a notational or
956 typographical element. For example, the Fingering object
957 has the following aspects
961 Its size is independent of the horizontal spacing, unlike slurs or beams.
964 It is a piece of text. Granted, it is usually a very short text.
967 That piece of text is typeset with a font, unlike slurs or beams.
970 Horizontally, the center of the symbol should be aligned to the
971 center of the note head.
974 Vertically, the symbol is placed next to the note and the staff.
977 The vertical position is also coordinated with other superscript
978 and subscript symbols.
981 Each of these aspects is captured in so-called @emph{interface}s,
982 which are listed on the @rinternals{Fingering} page at the bottom
985 This object supports the following interfaces:
986 @rinternals{item-interface},
987 @rinternals{self-alignment-interface},
988 @rinternals{side-position-interface}, @rinternals{text-interface},
989 @rinternals{text-script-interface}, @rinternals{font-interface},
990 @rinternals{finger-interface}, and @rinternals{grob-interface}.
993 Clicking any of the links will take you to the page of the respective
994 object interface. Each interface has a number of properties. Some of
995 them are not user-serviceable (@q{Internal properties}), but others
998 We have been talking of @emph{the} @code{Fingering} object, but actually it
999 does not amount to much. The initialization file (see
1000 @rlearning{Other sources of information})
1001 @file{scm/@/define@/-grobs@/.scm} shows the soul of the @q{object},
1006 (avoid-slur . around)
1007 (slur-padding . 0.2)
1008 (staff-padding . 0.5)
1009 (self-alignment-X . 0)
1010 (self-alignment-Y . 0)
1011 (script-priority . 100)
1012 (stencil . ,ly:text-interface::print)
1013 (direction . ,ly:script-interface::calc-direction)
1014 (font-encoding . fetaNumber)
1015 (font-size . -5) ; don't overlap when next to heads.
1016 (meta . ((class . Item)
1017 (interfaces . (finger-interface
1019 text-script-interface
1021 side-position-interface
1022 self-alignment-interface
1023 item-interface))))))
1027 As you can see, the @code{Fingering} object is nothing more than a
1028 bunch of variable settings, and the webpage in the Internals Reference
1029 is directly generated from this definition.
1032 @node Determining the grob property
1033 @subsection Determining the grob property
1035 @c TODO remove this (it's in the LM)
1036 @c Replace with more factual directions
1038 Recall that we wanted to change the position of the @b{2} in
1040 @lilypond[quote,fragment,relative=2,verbatim]
1046 Since the @b{2} is vertically positioned next to its note, we have to
1047 meddle with the interface associated with this positioning. This is
1048 done using @code{side-position-interface}. The page for this interface
1052 @code{side-position-interface}
1054 Position a victim object (this one) next to other objects (the
1055 support). The property @code{direction} signifies where to put the
1056 victim object relative to the support (left or right, up or down?)
1061 Below this description, the variable @code{padding} is described as
1066 (dimension, in staff space)
1068 Add this much extra space between objects that are next to each other.
1072 By increasing the value of @code{padding}, we can move the
1073 fingering away from the note head. The following command inserts
1074 3 staff spaces of white
1075 between the note and the fingering:
1077 \once \override Voice.Fingering #'padding = #3
1080 Inserting this command before the Fingering object is created,
1081 i.e., before @code{c2}, yields the following result:
1083 @lilypond[quote,relative=2,fragment,verbatim]
1084 \once \override Voice.Fingering #'padding = #3
1091 In this case, the context for this tweak is @code{Voice}. This
1092 fact can also be deduced from the program reference, for the page for
1093 the @rinternals{Fingering_engraver} plug-in says
1096 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1100 @node Naming conventions
1101 @subsection Naming conventions
1103 Another thing that is needed, is an overview of the various naming
1106 scheme functions: lowercase-with-hyphens (incl. one-word
1108 scheme functions: ly:plus-scheme-style
1109 music events, music classes and music properties:
1111 Grob interfaces: scheme-style
1112 backend properties: scheme-style (but X and Y!)
1113 contexts (and MusicExpressions and grobs): Capitalized or
1115 context properties: lowercaseFollowedByCamelCase
1117 Capitalized_followed_by_lowercase_and_with_underscores
1119 Which of these are conventions and which are rules?
1120 Which are rules of the underlying language, and which are
1124 @node Modifying properties
1125 @section Modifying properties
1127 @c TODO change the menu and subsection node names to use
1128 @c backslash once the new macro to handle the refs
1129 @c is available. Need to find and change all refs at
1130 @c the same time. -td
1133 * Overview of modifying properties::
1135 * The override command::
1136 * The tweak command::
1137 * set versus override::
1141 @node Overview of modifying properties
1142 @subsection Overview of modifying properties
1144 Each context is responsible for creating certain types of graphical
1145 objects. The settings used for printing these objects are also stored by
1146 context. By changing these settings, the appearance of objects can be
1149 The syntax for this is
1152 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1155 Here @var{name} is the name of a graphical object, like
1156 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1157 variable of the formatting system (@q{grob property} or @q{layout
1158 property}). The latter is a symbol, so it must be quoted. The
1159 subsection @ref{Modifying properties}, explains what to fill in
1160 for @var{name}, @var{property}, and @var{value}. Here we only
1161 discuss the functionality of this command.
1166 \override Staff.Stem #'thickness = #4.0
1170 makes stems thicker (the default is 1.3, with staff line thickness as a
1171 unit). Since the command specifies @code{Staff} as context, it only
1172 applies to the current staff. Other staves will keep their normal
1173 appearance. Here we see the command in action:
1175 @lilypond[quote,verbatim,relative=2,fragment]
1177 \override Staff.Stem #'thickness = #4.0
1183 The @code{\override} command changes the definition of the @code{Stem}
1184 within the current @code{Staff}. After the command is interpreted
1185 all stems are thickened.
1187 Analogous to @code{\set}, the @var{context} argument may be left out,
1188 causing the default context @code{Voice} to be used. Adding
1189 @code{\once} applies the change during one timestep only.
1191 @lilypond[quote,fragment,verbatim,relative=2]
1193 \once \override Stem #'thickness = #4.0
1198 The @code{\override} must be done before the object is
1199 started. Therefore, when altering @emph{Spanner} objects such as slurs
1200 or beams, the @code{\override} command must be executed at the moment
1201 when the object is created. In this example,
1203 @lilypond[quote,fragment,verbatim,relative=2]
1204 \override Slur #'thickness = #3.0
1206 \override Beam #'thickness = #0.6
1211 the slur is fatter but the beam is not. This is because the command for
1212 @code{Beam} comes after the Beam is started, so it has no effect.
1214 Analogous to @code{\unset}, the @code{\revert} command for a context
1215 undoes an @code{\override} command; like with @code{\unset}, it only
1216 affects settings that were made in the same context. In other words, the
1217 @code{\revert} in the next example does not do anything.
1220 \override Voice.Stem #'thickness = #4.0
1221 \revert Staff.Stem #'thickness
1224 Some tweakable options are called @q{subproperties} and reside inside
1225 properties. To tweak those, use commands of the form
1227 @c leave this as a long long
1229 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1236 \override Stem #'details #'beamed-lengths = #'(4 4 3)
1242 Internals: @rinternals{OverrideProperty}, @rinternals{RevertProperty},
1243 @rinternals{PropertySet}, @rinternals{Backend}, and
1244 @rinternals{All layout objects}.
1249 The back-end is not very strict in type-checking object properties.
1250 Cyclic references in Scheme values for properties can cause hangs
1251 or crashes, or both.
1255 @node The set command
1256 @subsection The @code{\set} command
1260 @cindex changing properties
1262 Each context can have different @emph{properties}, variables contained
1263 in that context. They can be changed during the interpretation step.
1264 This is achieved by inserting the @code{\set} command in the music,
1267 \set @var{context}.@var{prop} = #@var{value}
1271 @lilypond[quote,verbatim,relative=2,fragment]
1273 \set Score.skipBars = ##t
1277 This command skips measures that have no notes. The result is that
1278 multi-rests are condensed. The value assigned is a Scheme object. In
1279 this case, it is @code{#t}, the boolean True value.
1281 If the @var{context} argument is left out, then the current bottom-most
1282 context (typically @code{ChordNames}, @code{Voice}, or
1283 @code{Lyrics}) is used. In this example,
1285 @lilypond[quote,verbatim,relative=2,fragment]
1287 \set autoBeaming = ##f
1292 the @var{context} argument to @code{\set} is left out, so automatic
1293 beaming is switched off in the current @rinternals{Voice}. Note that
1294 the bottom-most context does not always contain the property that you
1295 wish to change -- for example, attempting to set the @code{skipBars}
1296 property (of the bottom-most context, in this case @code{Voice}) will
1299 @lilypond[quote,verbatim,relative=2,fragment]
1305 Contexts are hierarchical, so if a bigger context was specified, for
1306 example @code{Staff}, then the change would also apply to all
1307 @code{Voice}s in the current stave. The change is applied
1308 @q{on-the-fly}, during the music, so that the setting only affects the
1309 second group of eighth notes.
1313 There is also an @code{\unset} command,
1315 \unset @var{context}.@var{prop}
1319 which removes the definition of @var{prop}. This command removes
1320 the definition only if it is set in @var{context}, so
1323 \set Staff.autoBeaming = ##f
1327 introduces a property setting at @code{Staff} level. The setting also
1328 applies to the current @code{Voice}. However,
1331 \unset Voice.autoBeaming
1335 does not have any effect. To cancel this setting, the @code{\unset}
1336 must be specified on the same level as the original @code{\set}. In
1337 other words, undoing the effect of @code{Staff.autoBeaming = ##f}
1340 \unset Staff.autoBeaming
1343 Like @code{\set}, the @var{context} argument does not have to be
1344 specified for a bottom context, so the two statements
1347 \set Voice.autoBeaming = ##t
1348 \set autoBeaming = ##t
1356 Settings that should only apply to a single time-step can be entered
1357 with @code{\once}, for example in
1359 @lilypond[quote,verbatim,relative=2,fragment]
1361 \once \set fontSize = #4.7
1366 the property @code{fontSize} is unset automatically after the second
1369 A full description of all available context properties is in the
1370 program reference, see
1372 @rinternals{Tunable context properties}.
1375 Translation @expansion{} Tunable context properties.
1380 @node The override command
1381 @subsection The @code{\override} command
1383 Commands which change output generally look like
1386 \override Voice.Stem #'thickness = #3.0
1390 To construct this tweak we must determine these bits of information:
1393 @item the context: here @code{Voice}.
1394 @item the layout object: here @code{Stem}.
1395 @item the layout property: here @code{thickness}.
1396 @item a sensible value: here @code{3.0}.
1399 Some tweakable options are called @q{subproperties} and reside inside
1400 properties. To tweak those, use commands in the form
1403 \override Stem #'details #'beamed-lengths = #'(4 4 3)
1406 @cindex internal documentation
1407 @cindex finding graphical objects
1408 @cindex graphical object descriptions
1411 @cindex internal documentation
1413 For many properties, regardless of the data type of the property, setting the
1414 property to false ( @code{##f} ) will result in turning it off, causing
1415 LilyPond to ignore that property entirely. This is particularly useful for
1416 turning off grob properties which may otherwise be causing problems.
1418 We demonstrate how to glean this information from the notation manual
1419 and the program reference.
1422 @node The tweak command
1423 @subsection The @code{\tweak} command
1428 In some cases, it is possible to take a short-cut for tuning
1429 graphical objects. For objects that are created directly from
1430 an item in the input file, you can use the @code{\tweak} command.
1433 @lilypond[relative=2,verbatim]
1438 \tweak #'duration-log #1
1441 -\tweak #'padding #8
1445 @cindex chord, modifying one note in
1447 But the main use of the @code{\tweak} command is to modify just
1448 one of a number of notation elements which start at the same musical
1449 moment, like the notes of a chord, or tuplet brackets which start
1452 For an introduction to the syntax and uses of the tweak command
1453 see @rlearning{Tweaking methods}.
1455 The @code{\tweak} command sets a property in the following object
1456 directly, without requiring the grob name or context to be
1457 specified. For this to work, it is necessary for the @code{\tweak}
1458 command to remain immediately adjacent to the object to which it is
1459 to apply after the input file has been converted to a music stream.
1460 This is often not the case, as many additional elements are inserted
1461 into the music stream implicitly. For example, when a note which is
1462 not part of a chord is processed, Lilypond implicitly inserts a
1463 @code{ChordEvent} event before the note, so separating the tweak
1464 from the note. However, if chord symbols are placed round the
1465 tweak and the note, the @code{\tweak} command comes after the
1466 @code{ChordEvent} in the music stream, so remaining adjacent to the
1467 note, and able to modify it.
1471 @lilypond[relative=2,verbatim,quote]
1472 <\tweak #'color #red c>4
1478 @lilypond[relative=2,verbatim,quote]
1479 \tweak #'color #red c4
1482 When several similar items are placed at the same musical moment,
1483 the @code{\override} command cannot be used to modify just one of
1484 them -- this is where the @code{\tweak} command must be used.
1485 Items which may appear more than once at the same musical moment
1486 include the following:
1488 @c TODO expand to include any further uses of \tweak
1490 @item note heads of notes inside a chord
1491 @item articulation signs on a single note
1492 @item ties between notes in a chord
1493 @item tuplet brackets starting at the same time
1496 @c TODO add examples of these
1499 and @code{\tweak} may be used to modify any single occurrence of
1502 Notably the @code{\tweak} command cannot be used to modify stems,
1503 beams or accidentals, since these are generated later by note heads,
1504 rather than by music elements in the input stream. Nor can a
1505 @code{\tweak} command be used to modify clefs or time signatures,
1506 since these become separated from any preceding @code{\tweak}
1507 command in the input stream by the automatic insertion of extra
1508 elements required to specify the context.
1510 But the @code{\tweak} command can be used as an alternative to
1511 the @code{\override} command to modify those notational elements
1512 that do not cause any additional implicit elements to be added
1513 before them in the music stream. For example, slurs may be
1514 modified in this way:
1516 @lilypond[verbatim,quote,relative=1]
1517 c-\tweak #'thickness #5 ( d e f)
1520 Also several @code{\tweak} commands may be placed before a
1521 notational element -- all affect it:
1523 @lilypond[verbatim,quote,relative=1]
1525 -\tweak #'style #'dashed-line
1526 -\tweak #'dash-fraction #0.2
1527 -\tweak #'thickness #3
1528 -\tweak #'color #red
1533 The music stream which is generated from a section of an input file,
1534 including any automatically inserted elements, may be examined,
1535 see @ref{Displaying music expressions}. This may be helpful in
1536 determining what may be modified by a @code{\tweak} command.
1541 @rlearning{Tweaking methods}.
1544 @ref{Displaying music expressions}.
1548 @cindex tweaks in a variable
1549 The @code{\tweak} command cannot be used inside a variable.
1551 @cindex tweaks in lyrics
1552 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1554 @cindex tweaking control points
1555 @cindex control points, tweaking
1557 The @code{\tweak} command cannot be used to modify the control
1558 points of just one of several ties in a chord, other than the first
1559 one encountered in the input file.
1561 @node set versus override
1562 @subsection @code{\set} vs. @code{\override}
1564 We have seen two methods of changing properties: @code{\set} and
1565 @code{\override}. There are actually two different kinds of
1568 Contexts can have properties, which are usually named in
1569 @code{studlyCaps}. They mostly control the translation from
1570 music to notation, eg. @code{localKeySignature} (for determining
1571 whether to print accidentals), @code{measurePosition} (for
1572 determining when to print a bar line). Context properties can
1573 change value over time while interpreting a piece of music;
1574 @code{measurePosition} is an obvious example of
1575 this. Context properties are modified with @code{\set}.
1577 There is a special type of context property: the element
1578 description. These properties are named in @code{StudlyCaps}
1579 (starting with capital letters). They contain the
1580 @q{default settings} for said graphical object as an
1581 association list. See @file{scm/@/define@/-grobs@/.scm}
1582 to see what kind of settings there are. Element descriptions
1583 may be modified with @code{\override}.
1585 @code{\override} is actually a shorthand;
1588 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1592 is more or less equivalent to
1594 @c leave this long line -gp
1596 \set @var{context}.@var{name} #'@var{property} = #(cons (cons '@var{property} @var{value}) <previous value of @var{context})
1599 The value of @code{context} (the alist) is used to initialize
1600 the properties of individual grobs. Grobs also have
1601 properties, named in Scheme style, with
1602 @code{dashed-words}. The values of grob properties change
1603 during the formatting process: formatting basically amounts
1604 to computing properties using callback functions.
1606 @code{fontSize} is a special property: it is equivalent to
1607 entering @code{\override ... #'font-size} for all pertinent
1608 objects. Since this is a common change, the special
1609 property (modified with @code{\set}) was created.
1612 @node Useful concepts and properties
1613 @section Useful concepts and properties
1618 * Direction and placement::
1619 * Distances and measurements::
1621 * Visibility of objects::
1623 * Rotating objects::
1627 @subsection Input modes
1629 The way in which the notation contained within an input file is
1630 interpreted is determined by the current input mode.
1634 This is activated with the @code{\chordmode} command, and causes
1635 input to be interpreted with the syntax of chord notation, see
1636 @ref{Chord notation}. Chords are rendered as notes on a staff.
1638 Chord mode is also activated with the @code{\chords} command.
1639 This also creates a new @code{ChordNames} context and
1640 causes the following input to be interpreted with the syntax of
1641 chord notation and rendered as chord names in the @code{ChordNames}
1642 context, see @ref{Printing chord names}.
1646 This is activated with the @code{\drummode} command, and causes
1647 input to be interpreted with the syntax of drum notation, see
1648 @ref{Basic percussion notation}.
1650 Drum mode is also activated with the @code{\drums} command.
1651 This also creates a new @code{DrumStaff} context and causes the
1652 following input to be interpreted with the syntax of drum notation
1653 and rendered as drum symbols on a drum staff, see @ref{Basic
1654 percussion notation}.
1656 @strong{Figure mode}
1658 This is activated with the @code{\figuremode} command, and causes
1659 input to be interpreted with the syntax of figured bass, see
1660 @ref{Entering figured bass}.
1662 Figure mode is also activated with the @code{\figures} command.
1663 This also creates a new @code{FiguredBass} context and causes the
1664 following input to be interpreted with the figured bass syntax
1665 and rendered as figured bass symbols in the @code{FiguredBass}
1666 context, see @ref{Introduction to figured bass}.
1668 @strong{Fret and tab modes}
1670 There are no special input modes for entering fret and tab symbols.
1672 To create tab diagrams, enter notes or chords in note mode and
1673 render them in a @code{TabStaff} context, see
1674 @ref{Default tablatures}.
1676 To create fret diagrams above a staff, you have two choices.
1677 You can either use the @code{FretBoards} context (see
1678 @ref{Automatic fret diagrams} or you can enter them as a markup
1679 above the notes using the @code{\fret-diagram} command (see
1680 @ref{Fret diagram markups}).
1682 @strong{Lyrics mode}
1684 This is activated with the @code{\lyricmode} command, and causes
1685 input to be interpreted as lyric syllables with optional durations
1686 and associated lyric modifiers, see @ref{Vocal music}.
1688 Lyric mode is also activated with the @code{\addlyrics} command.
1689 This also creates a new @code{Lyrics} context and an implicit
1690 @code{\lyricsto} command which associates the following lyrics
1691 with the preceding music.
1693 @strong{Markup mode}
1695 This is activated with the @code{\markup} command, and causes
1696 input to be interpreted with the syntax of markup, see
1697 @ref{Text markup commands}.
1699 @c silly work-around for texinfo broken-ness
1700 @c (@strong{Note...} causes a spurious cross-reference in Info)
1703 This is the default mode or it may be activated with the
1704 @code{\notemode} command. Input is interpreted as pitches,
1705 durations, markup, etc and typeset as musical notation on a staff.
1707 It is not normally necessary to specify note mode explicitly, but
1708 it may be useful to do so in certain situations, for example if you
1709 are in lyric mode, chord mode or any other mode and want to insert
1710 something that only can be done with note mode syntax.
1712 For example, to indicate dynamic markings for the verses of a
1713 choral pieces it is necessary to enter note mode to interpret
1716 @lilypond[verbatim,relative=2,quote]
1719 \notemode{\set stanza = \markup{ \dynamic f 1. } }
1723 \notemode{\set stanza = \markup{ \dynamic p 2. } }
1730 @node Direction and placement
1731 @subsection Direction and placement
1733 In typesetting music the direction and placement of many items is
1734 a matter of choice. For example, the stems of notes can
1735 be directed up or down; lyrics, dynamics, and other expressive
1736 marks may be placed above or below the staff; text may be aligned
1737 left, right or center; etc. Most of these choices may be left to
1738 be determined automatically by LilyPond, but in some cases it may
1739 be desirable to force a particular direction or placement.
1741 @strong{Default actions}
1743 By default some directions are always up or always down (e.g.
1744 dynamics or fermata), while other things can alternate between
1745 up or down based on the stem direction (like slurs or accents).
1747 @c TODO Add table showing these
1749 @strong{Context layout}
1751 Contexts are positioned in a system from top to bottom in the
1752 order in which they are encountered. Note, however, that a
1753 context will be created implicitly if a command is encountered
1754 when there is no suitable context available to contain it.
1756 @c TODO Add example ?
1758 The default order in which contexts are laid out can be changed,
1759 see @ref{Aligning contexts}
1761 @strong{Articulation direction indicators}
1763 When adding articulations to notes the direction indicator,
1764 @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down}) or
1765 @code{-} (meaning @qq{use default direction}), can usually be
1766 omitted, in which case @code{-} is assumed. But a direction
1767 indicator is @strong{always} required before
1770 @item @code{\tweak} commands
1771 @item @code{\markup} commands
1772 @item @code{\tag} commands
1773 @item string markups, e.g. -"string"
1774 @item fingering instructions, e.g. @code{-1}
1775 @item articulation shortcuts, e.g. @code{-.}, @code{->}, @code{--}
1778 @strong{The direction property}
1780 The position or direction of many layout objects is controlled
1781 by the @code{direction} property.
1783 The value of the @code{direction} property may be
1784 set to @code{1}, meaning @qq{up} or @qq{above}, or to @code{-1},
1785 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
1786 @code{DOWN} may be used instead of @code{1} and @code{-1}
1787 respectively. The default direction may be specified by setting
1788 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
1789 in many cases predefined commands
1790 exist to specify the direction. These are all of the form
1793 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
1796 where @code{xxxNeutral} means @qq{use the default direction}.
1797 See @rlearning{Within-staff objects}.
1799 In a few cases, arpeggio being the only common example, the value
1800 of the @code{direction} property specifies whether the object
1801 is to be placed to the right or left of the parent object. In
1802 this case @code{-1} or @code{LEFT} means @qq{to the left} and
1803 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
1804 or @code{CENTER} means @qq{use the default} direction, as before.
1807 These all have side-axis set to #X
1808 AmbitusAccidental - direction has no effect
1810 StanzaNumber - not tried
1811 TrillPitchAccidental - not tried
1812 TrillPitchGroup - not tried
1817 @node Distances and measurements
1818 @subsection Distances and measurements
1820 @cindex distances, absolute
1821 @cindex distances, scaled
1828 Distances in LilyPond are of two types: absolute and scaled.
1830 Absolute distances are used for specifying margins, indents, and
1831 other page layout details, and are by default specified in
1832 millimeters. Distances may be specified in other units by
1833 following the quantity by @code{\mm}, @code{\cm},
1834 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27
1835 of an inch). Page layout distances can also be specified in
1836 scalable units (see the following paragraph) by appending
1837 @code{\staff-space} to the quantity.
1838 Page layout is described in detail in @ref{Page formatting}.
1840 Scaled distances are always specified in units of the staff-space
1841 or, rarely, the half staff-space. The staff-space is the distance
1842 between two adjacent staff lines. The default value can be changed
1843 globally by setting the global staff size, or it can be overridden
1844 locally by changing the @code{staff-space} property of
1845 @code{StaffSymbol}. Scaled distances automatically scale with any
1846 change to the either the global staff size or the
1847 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
1848 automatically only with changes to the global staff size.
1849 The global staff size thus enables the overall size of a rendered
1850 score to be easily varied. For the methods of setting the global
1851 staff size see @ref{Setting the staff size}.
1855 If just a section of a score needs to be rendered to a different
1856 scale, for example an ossia section or a footnote, the global staff
1857 size cannot simply be changed as this would affect the entire score.
1858 In such cases the change in size is made by overriding both the
1859 @code{staff-space} property of @code{StaffSymbol} and the size of
1860 the fonts. A Scheme function, @code{magstep}, is available to
1861 convert from a font size change to the equivalent change in
1862 @code{staff-space}. For an explanation and an example of its use,
1863 see @rlearning{Length and thickness of objects}.
1868 @rlearning{Length and thickness of objects}.
1871 @ref{Page formatting},
1872 @ref{Setting the staff size}.
1876 @subsection Spanners
1878 Many objects of musical notation extend over several notes or even
1879 several bars. Examples are slurs, beams, tuplet brackets, volta
1880 repeat brackets, crescendi, trills, and glissandi. Such objects
1881 are collectively called @qq{spanners}, and have special properties to control
1882 their appearance and behaviour. Some of these properties are common
1883 to all spanners; others are restricted to a sub-set of the spanners.
1885 All spanners support the @code{spanner-interface}. A few, esentially
1886 those that draw a straight line between the two objects, support in
1887 addition the @code{line-spanner-interface}.
1889 @unnumberedsubsubsec Using the @code{spanner-interface}
1891 This interface provides two properties that apply to several spanners.
1893 @strong{@i{The @code{minimum-length} property}}
1895 The minimum length of the spanner is specified by the
1896 @code{minimum-length} property. Increasing this usually has the
1897 necessary effect of increasing the spacing of the notes between the
1898 two end points. However, this override has no effect on
1899 many spanners, as their length is determined by other considerations.
1900 A few examples where it is effective are shown below.
1910 Works as long as callback is made:
1914 Works not at all for:
1923 @lilypond[verbatim,quote,relative=2]
1926 % increase the length of the tie
1927 -\tweak #'minimum-length #5
1931 @lilypond[verbatim,quote,relative=2]
1933 \compressFullBarRests
1935 % increase the length of the rest bar
1936 \once \override MultiMeasureRest #'minimum-length = #20
1941 @lilypond[verbatim,quote,relative=2]
1943 % increase the length of the hairpin
1944 \override Hairpin #'minimum-length = #20
1948 This override can also be used to increase the length of slurs and
1951 @lilypond[verbatim,quote,relative=2]
1954 -\tweak #'minimum-length #5
1959 -\tweak #'minimum-length #5
1963 For some layout objects, the @code{minimum-length} property becomes
1964 effective only if the @code{set-spacing-rods} procedure is called
1965 explicitly. To do this, the @code{springs-and-rods} property should
1966 be set to @code{ly:spanner::set-spacing-rods}. For example,
1967 the minimum length of a glissando has no effect unless the
1968 @code{springs-and-rods} property is set:
1970 @lilypond[verbatim,quote,relative=1]
1974 % not effective alone
1975 \once \override Glissando #'minimum-length = #20
1978 % effective only when both overrides are present
1979 \once \override Glissando #'minimum-length = #20
1980 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
1984 The same is true of the @code{Beam} object:
1986 @lilypond[verbatim,quote,relative=1]
1987 % not effective alone
1988 \once \override Beam #'minimum-length = #20
1991 % effective only when both overrides are present
1992 \once \override Beam #'minimum-length = #20
1993 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
1997 @strong{@i{The @code{to-barline} property}}
1999 The second useful property of the @code{spanner-interface} is
2000 @code{to-barline}. By default this is true, causing hairpins and
2001 other spanners which are terminated on the first note of a measure to
2002 end instead on the immediately preceding bar line. If set to false,
2003 the spanner will extend beyond the bar line and end on the note
2006 @lilypond[verbatim,quote,relative=2]
2007 a \< a a a a \! a a a \break
2008 \override Hairpin #'to-barline = ##f
2009 a \< a a a a \! a a a
2012 This property is not effective for all spanners. For example,
2013 seting it to @code{#t} has no effect on slurs or phrasing slurs
2014 or on other spanners for which terminating on the bar line would
2017 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2019 Objects which support the @code{line-spanner-interface} include
2022 @item @code{DynamicTextSpanner}
2023 @item @code{Glissando}
2024 @item @code{TextSpanner}
2025 @item @code{TrillSpanner}
2026 @item @code{VoiceFollower}
2029 The routine responsible for drawing the stencils for these spanners is
2030 @code{ly:line-interface::print}. This routine determines the
2031 exact location of the two end points and draws a line
2032 between them, in the style requested. The locations of the two
2033 end points of the spanner are computed on-the-fly, but it is
2034 possible to override their Y-coordinates. The
2035 properties which need to be specified are nested
2036 two levels down within the property hierarchy, but the syntax of
2037 the @code{\override} command is quite simple:
2039 @lilypond[relative=2,quote,verbatim]
2041 \once \override Glissando #'bound-details #'left #'Y = #3
2042 \once \override Glissando #'bound-details #'right #'Y = #-2
2046 The units for the @code{Y} property are @code{staff-space}s,
2047 with the center line of the staff being the zero point.
2048 For the glissando, this is the value for @code{Y} at the
2049 X-coordinate corresponding to the center point of each note head,
2050 if the line is imagined to be extended to there.
2052 If @code{Y} is not set, the value is computed from the vertical
2053 position of the corresponding attachment point of the spanner.
2055 In case of a line break, the values for the end points are
2056 specified by the @code{left-broken} and @code{right-broken}
2057 sub-lists of @code{bound-details}. For example:
2059 @lilypond[relative=2,ragged-right,verbatim,fragment]
2060 \override Glissando #'breakable = ##t
2061 \override Glissando #'bound-details #'right-broken #'Y = #-3
2062 c1 \glissando \break
2067 A number of further properties of the @code{left} and
2068 @code{right} sub-lists of the @code{bound-details} property
2069 may be modified in the same way as @code{Y}:
2073 This sets the Y-coordinate of the end point, in @code{staff-space}s
2074 offset from the staff center line. By default, it is the center of
2075 the bound object, so a glissando points to the vertical center of
2078 For horizontal spanners, such as text spanners and trill spanners,
2079 it is hardcoded to 0.
2082 This determines where the line starts and ends in the X-direction,
2083 relative to the bound object. So, a value of @code{-1} (or
2084 @code{LEFT}) makes the line start/end at the left side of the note
2085 head it is attached to.
2088 This is the absolute X-coordinate of the end point. It is usually
2089 computed on the fly, and overriding it has little useful effect.
2092 Line spanners may have symbols at the beginning or end, which is
2093 contained in this sub-property. This is for internal use; it is
2094 recommended that @code{text} be used instead.
2097 This is a markup that is evaluated to yield the stencil. It is used
2098 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2100 @lilypond[quote,ragged-right,fragment,relative=2,verbatim]
2101 \override TextSpanner #'bound-details #'left #'text
2102 = \markup { \small \bold Slower }
2103 c2\startTextSpan b c a\stopTextSpan
2106 @item stencil-align-dir-y
2107 @item stencil-offset
2108 Without setting one of these, the stencil is simply put at the
2109 end-point, centered on the line, as defined by the @code{X} and
2110 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2111 or @code{stencil-offset} will move the symbol at the edge vertically
2112 relative to the end point of the line:
2114 @lilypond[relative=1,fragment,verbatim]
2115 \override TextSpanner #'bound-details
2116 #'left #'stencil-align-dir-y = #-2
2117 \override TextSpanner #'bound-details
2118 #'right #'stencil-align-dir-y = #UP
2120 \override TextSpanner #'bound-details
2121 #'left #'text = #"ggg"
2122 \override TextSpanner #'bound-details
2123 #'right #'text = #"hhh"
2124 c4^\startTextSpan c c c \stopTextSpan
2127 Note that negative values move the text @emph{up}, contrary to the
2128 effect that might be expected, as a value of @code{-1} or
2129 @code{DOWN} means align the @emph{bottom} edge of the text with
2130 the spanner line. A value of @code{1} or @code{UP} aligns
2131 the top edge of the text with the spanner line.
2134 Setting this sub-property to @code{#t} produces an arrowhead at the
2138 This sub-property controls the space between the specified
2139 end point of the line and the actual end. Without padding, a
2140 glissando would start and end in the center of each note head.
2144 The music function @code{\endSpanners} terminates the spanner
2145 which starts on the immediately following note prematurely. It
2146 is terminated after exactly one note, or at the following bar line
2147 if @code{to-barline} is true and a bar line occurs before the next
2150 @lilypond[verbatim,quote,ragged-right,relative=2,fragment]
2152 c2 \startTextSpan c2 c2
2157 When using @code{\endSpanners} it is not necessary to close
2158 \startTextSpan with \stopTextSpan, nor is it necessary to close
2159 hairpins with @code{\!}.
2165 Internals Reference: @rinternals{TextSpanner},
2166 @rinternals{Glissando}, @rinternals{VoiceFollower},
2167 @rinternals{TrillSpanner},
2168 @rinternals{line-spanner-interface}.
2171 @node Visibility of objects
2172 @subsection Visibility of objects
2174 @cindex objects, visibility of
2175 @cindex grobs, visibility of
2176 @cindex visibility of objects
2178 There are four main ways in which the visibility of layout objects
2179 can be controlled: their stencil can be removed, they can be made
2180 transparent, they can be colored white, or their
2181 @code{break-visibility} property can be overridden. The first
2182 three apply to all layout objects; the last to just a few -- the
2183 @emph{breakable} objects. The Learning Manual introduces these
2184 four techniques, see @rlearning{Visibility and color of objects}.
2186 There are also a few other techniques which are specific to
2187 certain layout objects. These are covered under Special
2191 * Removing the stencil::
2192 * Making objects transparent::
2193 * Painting objects white::
2194 * Using break-visibility::
2195 * Special considerations::
2199 @node Removing the stencil
2200 @unnumberedsubsubsec Removing the stencil
2202 @cindex stencil, removing
2204 Every layout object has a stencil property. By default this is set
2205 to the specific function which draws that object. If this property
2206 is overridden to @code{#f} no function will be called and the object
2207 will not be drawn. The default action can be recovered with
2210 @lilypond[quote,verbatim,relative=1]
2212 \override Score.BarLine #'stencil = ##f
2214 \revert Score.BarLine #'stencil
2218 @node Making objects transparent
2219 @unnumberedsubsubsec Making objects transparent
2221 @cindex transparent, making objects
2223 Every layout object has a transparent property which by default is
2224 set to @code{#f}. If set to @code{#t} the object still occupies
2225 space but is made invisible.
2227 @lilypond[quote,verbatim,relative=2]
2229 \once \override NoteHead #'transparent = ##t
2233 @node Painting objects white
2234 @unnumberedsubsubsec Painting objects white
2236 @cindex objects, coloring
2237 @cindex coloring objects
2239 @cindex printing order
2240 @cindex overwriting objects
2241 @cindex objects, overwriting
2242 @cindex grobs, overwriting
2244 Every layout object has a color property which by default is set
2245 to @code{black}. If this is overridden to @code{white} the object
2246 will be indistinguishable from the white background. However,
2247 if the object crosses other objects the color of the crossing
2248 points will be determined by the order in which they are drawn,
2249 and this may leave a ghostly image of the white object, as shown
2252 @lilypond[quote,verbatim,relative=2]
2253 \override Staff.Clef #'color = #white
2257 This may be avoided by changing the order of printing the objects.
2258 All layout objects have a @code{layer} property which should be set
2259 to an integer. Objects with the lowest value of @code{layer} are
2260 drawn first, then objects with progressively higher values are drawn,
2261 so objects with higher values overwrite objects with lower values.
2262 By default most objects are assigned a @code{layer} value of
2263 @code{1}, although a few objects, including @code{StaffSymbol} and
2264 @code{BarLine}, are assigned a value of @code{0}. The order of
2265 printing objects with the same value of @code{layer} is indeterminate.
2267 In the example above the white clef, with a default @code{layer}
2268 value of @code{1}, is drawn after the staff lines (default
2269 @code{layer} value @code{0}), so overwriting them. To change this,
2270 the @code{Clef} object must be given in a lower value of
2271 @code{layer}, say @code{-1}, so that it is drawn earlier:
2273 @lilypond[quote,verbatim,relative=2]
2274 \override Staff.Clef #'color = #white
2275 \override Staff.Clef #'layer = #-1
2279 @node Using break-visibility
2280 @unnumberedsubsubsec Using break-visibility
2282 @c TODO Add making other objects breakable
2284 @cindex break-visibility
2286 Most layout objects are printed only once, but some like
2287 bar lines, clefs, time signatures and key signatures, may need
2288 to be printed twice when a line break occurs -- once at the end
2289 of the line and again at the start of the next line. Such
2290 objects are called @emph{breakable}, and have a property, the
2291 @code{break-visibility} property to control their visibility
2292 at the three positions in which they may appear -- at the
2293 start of a line, within a line if they are changed, and at the
2294 end of a line if a change takes place there.
2296 For example, the time signature
2297 by default will be printed at the start of the first line, but
2298 nowhere else unless it changes, when it will be printed at the
2299 point at which the change occurs. If this change occurs at the
2300 end of a line the new time signature will be printed at the start
2301 of the next line and a cautionary time signature will be printed
2302 at the end of the previous line as well.
2304 This behaviour is controlled by the @code{break-visibility}
2305 property, which is explained in
2306 @c Leave this ref on a newline - formats incorrectly otherwise -td
2307 @rlearning{Visibility and color of objects}. This property takes
2308 a vector of three booleans which, in order, determine whether the
2309 object is printed at the end of, within the body of, or at the
2310 beginning of a line. Or to be more precise, before a line break,
2311 where there is no line break, or after a line break.
2313 Alternatively, seven of the eight combinations may be specified
2314 by pre-defined functions, defined in @file{scm/output-lib.scm},
2315 where the last three columns indicate whether the layout objects
2316 will be visible in the positions shown at the head of the columns:
2318 @multitable @columnfractions .40 .15 .1 .1 .1
2319 @c TODO check these more carefully
2320 @headitem Function @tab Vector @tab Before @tab At no @tab After
2321 @headitem form @tab form @tab break @tab break @tab break
2323 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @ @ @tab no @tab no @tab no
2324 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2325 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2326 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2327 @c The center-visible function is not defined
2328 @c @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2329 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2330 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2331 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2334 The @code{center-visible} function is not pre-defined.
2336 The default settings of @code{break-visibility} depend on the
2337 layout object. The following table shows all the layout objects
2338 of interest which are affected by @code{break-visibility} and the
2339 default setting of this property:
2341 @multitable @columnfractions .3 .3 .4
2343 @headitem Layout object @tab Usual context @tab Default setting
2345 @c omit Ambitus as it appears not to be affected by break-visibility -td
2346 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2347 @item @code{BarLine} @tab @code{Score} @tab calculated
2348 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2349 @c omit the following item until it can be explained -td
2350 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2351 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2352 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2353 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2354 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2355 @c omit KeyCancellation until it can be explained -td
2356 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2357 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2358 @c omit LeftEdge until it can be explained -td
2359 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2360 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2361 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2362 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2366 The example below shows the use of the vector form to control the
2367 visibility of barlines:
2369 @lilypond[quote,verbatim,relative=1,ragged-right]
2372 % Remove bar line at the end of the current line
2373 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2379 Although all three components of the vector used to override
2380 @code{break-visibility} must be present, not all of them are
2381 effective with every layout object, and some combinations may
2382 even give errors. The following limitations apply:
2385 @item Bar lines cannot be printed at start of line.
2386 @item A bar number cannot be printed at the start of the first
2387 line unless it is set to be different from 1.
2388 @item Clef -- see below
2389 @item Double percent repeats are either all printed or all
2390 suppressed. Use begin-of line-invisible to print and
2391 all-invisible to suppress.
2392 @item Key signature -- see below
2393 @item OctavateEight -- see below
2396 @node Special considerations
2397 @unnumberedsubsubsec Special considerations
2399 @strong{@emph{Visibility following explicit changes}}
2401 @cindex key signature, visibility following explicit change
2402 @cindex explicitKeySignatureVisibility
2403 @cindex clef, visibility following explicit change
2404 @cindex explicitClefVisibility
2406 The @code{break-visibility} property controls the visibility of
2407 key signatures and changes of clef only at the start of lines,
2408 i.e. after a break. It has no effect on the visibility of the
2409 key signature or clef following an explicit key change or an
2410 explicit clef change within or at the end of a line. In the
2411 following example the key signature following the explicit change
2412 to B-flat major is still visible, even though @code{all-invisible}
2415 @lilypond[quote,verbatim,relative=1,ragged-right]
2418 % Try to remove all key signatures
2419 \override Staff.KeySignature #'break-visibility = #all-invisible
2427 The visibility of such explicit key signature and clef changes is
2428 controlled by the @code{explicitKeySignatureVisibility} and
2429 @code{explicitClefVisibility} properties. These are the equivalent
2430 of the @code{break-visibility} property and both take a vector of
2431 three booleans or the predefined functions listed above, exactly like
2432 @code{break-visibility}. Both are properties of the Staff context,
2433 not the layout objects themselves, and so they are set using the
2434 @code{\set} command. Both are set by default to @code{all-visible}.
2435 These properties control only the visibility of key signatures and
2436 clefs resulting from explicit changes and do not affect key
2437 signatures and clefs at the beginning of lines;
2438 @code{break-visibility} must still be overridden in the appropriate
2439 object to remove these.
2441 @lilypond[quote,verbatim,relative=1,ragged-right]
2444 \set Staff.explicitKeySignatureVisibility = #all-invisible
2445 \override Staff.KeySignature #'break-visibility = #all-invisible
2452 @strong{@emph{Visibility of cautionary accidentals}}
2454 To remove the cautionary accidentals printed at an explicit key
2455 change, set the Staff context property @code{printKeyCancellation}
2458 @lilypond[quote,verbatim,relative=1,ragged-right]
2461 \set Staff.explicitKeySignatureVisibility = #all-invisible
2462 \set Staff.printKeyCancellation = ##f
2463 \override Staff.KeySignature #'break-visibility = #all-invisible
2470 With these overrides only the accidentals before the notes remain
2471 to indicate the change of key.
2473 @c TODO Add visibility of cautionary accidentals before notes
2475 @strong{@emph{Automatic bars}}
2477 @cindex automaticBars
2478 @cindex bar lines, suppressing
2480 As a special case, the printing of bar lines can also be turned off
2481 by setting the @code{automaticBars} property in the Score context.
2482 If set to @code{#f}, bar lines will not be printed automatically;
2483 they must be explicitly created with a @code{\bar} command. Unlike
2484 the @code{\cadenzaOn} predefined command, measures are still counted.
2485 Bar generation will resume according to that count if this property
2486 is later set to @code{#t}. When set to @code{#f}, line breaks can
2487 occur only at explicit @code{\bar} commands.
2491 @strong{@emph{Octavated clefs}}
2493 @cindex octavated clefs, visibility of
2494 @cindex visibility of octavated clefs
2495 @cindex clefs, visibility of octavation
2497 The small octavation symbol on octavated clefs is produced by the
2498 @code{OctavateEight} layout object. Its visibility is controlled
2499 independently from that of the @code{Clef} object, so it is
2500 necessary to apply any required @code{break-visibility} overrides
2501 to both the @code{Clef} and the @code{OctavateEight} layout objects
2502 to fully suppress such clef symbols at the start of each line.
2504 For explicit clef changes, the @code{explicitClefVisibility}
2505 property controls both the clef symbol and any octavation symbol
2511 @rlearning{Visibility and color of objects}
2515 @subsection Line styles
2517 Some performance indications, e.g., @i{rallentando} and
2518 @i{accelerando} and @i{trills} are written as text and are
2519 extended over many measures with lines, sometimes dotted or wavy.
2521 These all use the same routines as the glissando for drawing the
2522 texts and the lines, and tuning their behavior is therefore also
2523 done in the same way. It is done with a spanner, and the routine
2524 responsible for drawing the spanners is
2525 @code{ly:line-interface::print}. This routine determines the
2526 exact location of the two @i{span points} and draws a line
2527 between them, in the style requested.
2529 Here is an example showing the different line styles available,
2530 and how to tune them.
2532 @lilypond[relative=2,ragged-right,verbatim,fragment]
2534 \once \override Glissando #'style = #'dashed-line
2536 \override Glissando #'style = #'dotted-line
2538 \override Glissando #'style = #'zigzag
2540 \override Glissando #'style = #'trill
2544 The locations of the end-points of the spanner are computed
2545 on-the-fly for every graphic object, but it is possible to
2549 @lilypond[relative=2,ragged-right,verbatim,fragment]
2551 \once \override Glissando #'bound-details #'right #'Y = #-2
2555 The value for @code{Y} is set to @code{-2} for the right end
2556 point. The left side may be similarly adjusted by specifying
2557 @code{left} instead of @code{right}.
2559 If @code{Y} is not set, the value is computed from the vertical
2560 position of the left and right attachment points of the spanner.
2562 Other adjustments of spanners are possible, for details, see
2565 @node Rotating objects
2566 @subsection Rotating objects
2568 Both layout objects and elements of markup text can be rotated by
2569 any angle about any point, but the method of doing so differs.
2572 * Rotating layout objects::
2576 @node Rotating layout objects
2577 @unnumberedsubsubsec Rotating layout objects
2579 @cindex rotating objects
2580 @cindex objects, rotating
2582 All layout objects which support the @code{grob-interface} can be
2583 rotated by setting their @code{rotation} property. This takes a
2584 list of three items: the angle of rotation counter-clockwise,
2585 and the x and y coordinates of the point relative to the object's
2586 reference point about which the rotation is to be performed. The
2587 angle of rotation is specified in degrees and the coordinates in
2590 The angle of rotation and the coordinates of the rotation point must
2591 be determined by trial and error.
2593 @cindex hairpins, angled
2594 @cindex angled hairpins
2596 There are only a few situations where the rotation of layout
2597 objects is useful; the following example shows one situation where
2600 @lilypond[quote,verbatim,relative=1]
2602 \override Hairpin #'rotation = #'(20 -1 0)
2606 @node Rotating markup
2607 @unnumberedsubsubsec Rotating markup
2609 All markup text can be rotated to lie at any angle by prefixing it
2610 with the @code{\rotate} command. The command takes two arguments:
2611 the angle of rotation in degrees counter-clockwise and the text to
2612 be rotated. The extents of the text are not rotated: they take
2613 their values from the extremes of the x and y coordinates of the
2614 rotated text. In the following example the
2615 @code{outside-staff-priority} property for text is set to @code{#f}
2616 to disable the automatic collision avoidance, which would push some
2617 of the text too high.
2619 @lilypond[quote,verbatim,relative=1]
2620 \override TextScript #'outside-staff-priority = ##f
2621 g4^\markup { \rotate #30 "a G" }
2622 b^\markup { \rotate #30 "a B" }
2623 des^\markup { \rotate #30 "a D-Flat" }
2624 fis^\markup { \rotate #30 "an F-Sharp" }
2627 @node Advanced tweaks
2628 @section Advanced tweaks
2630 This section discusses various approaches to fine tuning the
2631 appearance of the printed score.
2634 * Aligning objects::
2635 * Vertical grouping of grobs::
2636 * Modifying stencils::
2637 * Modifying shapes::
2643 @rlearning{Tweaking output},
2644 @rlearning{Other sources of information}.
2647 @ref{Explaining the Internals Reference},
2648 @ref{Modifying properties},
2649 @ref{Interfaces for programmers}.
2652 @file{scm/@/define@/-grobs@/.scm}.
2655 @rlsr{Tweaks and overrides}.
2657 Internals Reference:
2658 @rinternals{All layout objects}.
2660 @node Aligning objects
2661 @subsection Aligning objects
2663 Graphical objects which support the @code{self-alignment-interface} and/or
2664 the @code{side-position-interface} can be
2665 aligned to a previously placed object in a variety of ways. For a list of these objects, see
2666 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
2668 All graphical objects have a reference point, a horizontal extent and a
2669 vertical extent. The horizontal extent is a pair of numbers
2670 giving the displacements from the reference point of the left and
2671 right edges, displacements to the left being negative. The
2672 vertical extent is a pair of numbers giving the displacement from
2673 the reference point to the bottom and top edges, displacements down
2676 An object's position on a staff is given by the values of the
2677 @code{X-offset} and @code{Y-offset} properties. The value of
2678 @code{X-offset} gives the displacement from the x coordinate of
2679 the reference point of the parent object, and the value of
2680 @code{Y-offset} gives the displacement from the center line of the
2681 staff. The values of @code{X-offset} and
2682 @code{Y-offset} may be set directly or may be set to be calculated
2683 by procedures in order to achieve alignment with the parent object
2686 @warning{Many objects have special positioning considerations which
2687 cause any setting of @code{X-offset} or @code{Y-offset} to be
2688 ignored or modified, even though the object supports the
2689 @code{self-alignment-interface}.}
2691 For example, an accidental can be repositioned
2692 vertically by setting @code{Y-offset} but any changes to
2693 @code{X-offset} have no effect.
2695 Rehearsal marks may be aligned with
2696 breakable objects such as bar lines, clef symbols, time signature
2697 symbols and key signatures. There are special properties to be
2698 found in the @code{break-aligned-interface} for positioning rehearsal
2699 marks on such objects.
2702 * Setting @code{X-offset} and @code{Y-offset} directly::
2703 * Using the @code{side-position-interface}::
2704 * Using the @code{self-alignment-interface}::
2705 * Using the @code{break-aligned-interface}::
2708 @node Setting @code{X-offset} and @code{Y-offset} directly
2709 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
2711 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
2712 properties of many objects. The following example shows three
2713 notes with the default fingering position and the positions with @code{X-offset}
2714 and @code{Y-offset} modified.
2716 @lilypond[verbatim,quote,relative=2]
2719 -\tweak #'X-offset #0
2720 -\tweak #'Y-offset #0
2723 -\tweak #'X-offset #-1
2724 -\tweak #'Y-offset #1
2730 @node Using the @code{side-position-interface}
2731 @unnumberedsubsubsec Using the @code{side-position-interface}
2733 An object which supports the @code{side-position-interface} can be
2734 placed next to its parent object so that
2735 the specified edges of the two objects touch. The object may be
2736 placed above, below, to the right or to the left of the parent.
2737 The parent cannot be specified; it is determined by the order of
2738 elements in the input stream. Most objects have the associated
2739 note head as their parent.
2741 The values of the @code{side-axis} and @code{direction} properties
2742 determine where the object is to be placed, as follows:
2744 @c TODO add an example of each to the table
2746 @multitable @columnfractions .3 .3 .3
2747 @headitem @code{side-axis} @tab @code{direction} @tab
2748 @headitem property @tab property @tab Placement
2750 @item @code{0} @tab @code{-1} @tab left
2751 @item @code{0} @tab @code{1} @tab right
2752 @item @code{1} @tab @code{-1} @tab below
2753 @item @code{1} @tab @code{1} @tab above
2757 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
2758 the procedure @code{ly:side-position-interface::x-aligned-side}.
2759 This procedure will return the correct value of @code{X-offset} to
2760 place the object to the left or right side of the parent according
2761 to value of @code{direction}.
2763 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
2764 the procedure @code{ly:side-position-interface::y-aligned-side}.
2765 This procedure will return the correct value of @code{Y-offset} to
2766 place the object to the top or bottom of the parent according
2767 to value of @code{direction}.
2769 @c TODO Add examples
2771 @node Using the @code{self-alignment-interface}
2772 @unnumberedsubsubsec Using the @code{self-alignment-interface}
2774 @emph{Self-aligning objects horizontally}
2776 The horizontal alignment of an object which supports the
2777 @code{self-alignment-interface} is controlled by the value of
2778 the @code{self-alignment-X} property, provided the object's
2779 @code{X-offset} property is set to
2780 @code{ly:self-alignment-interface::x-aligned-on-self}.
2781 @code{self-alignment-X} may be given any
2782 real value, in units of half the total X extent of the
2783 object. Negative values move the object to the right, positive
2784 to the left. A value of @code{0} centers the object on the
2785 reference point of its parent, a value of @code{-1} aligns the
2786 left edge of the object on the reference point of its parent,
2787 and a value of @code{1} aligns the right edge of the object on the
2788 reference point of its parent. The symbols @code{LEFT},
2789 @code{CENTER} and @code{RIGHT} may be used instead of the values
2790 @code{-1, 0, 1} respectively.
2792 Normally the @code{\override} command would be used to modify the
2793 value of @code{self-alignment-X}, but the @code{\tweak} command
2794 can be used to separately align several annotations on a single
2797 @lilypond[quote,verbatim,relative=1]
2799 -\tweak #'self-alignment-X #-1
2801 -\tweak #'self-alignment-X #0
2803 -\tweak #'self-alignment-X #RIGHT
2805 -\tweak #'self-alignment-X #-2.5
2806 ^"aligned further to the right"
2809 @emph{Self-aligning objects vertically}
2811 Objects may be aligned vertically in an analogous way to aligning
2812 them horizontally if the @code{Y-offset} property is set to
2813 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
2814 other mechanisms are often involved in vertical alignment: the
2815 value of @code{Y-offset} is just one variable taken into account.
2816 This may make adjusting the value of some objects tricky.
2817 The units are just half the vertical extent of the object, which
2818 is usually quite small, so quite large numbers may be required.
2819 A value of @code{-1} aligns the lower edge of the object with
2820 the reference point of the parent object, a value of @code{0}
2821 aligns the center of the object with the reference point of the
2822 parent, and a value of @code{1} aligns the top edge of the object
2823 with the reference point of the parent. The symbols @code{DOWN},
2824 @code{CENTER}, @code{UP} may be substituted for @code{-1, 0, 1}
2827 @emph{Self-aligning objects in both directions}
2829 By setting both @code{X-offset} and @code{Y-offset}, an object may
2830 be aligned in both directions simultaneously.
2832 The following example shows how to adjust a fingering mark so
2833 that it nestles close to the note head.
2835 @lilypond[quote,verbatim,relative=2]
2837 -\tweak #'self-alignment-X #0.5 % move horizontally left
2838 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
2839 -\tweak #'self-alignment-Y #-1 % move vertically up
2844 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
2846 @c Cannot document as they do not seem to operate consistently on all objects -td
2847 @c TODO investigate further
2849 The @code{aligned-on-parent} procedures are used in the same way
2850 as the @code{aligned-on-self} procedures, they difference being
2851 that they permit an object to be aligned with the @emph{edges} of
2852 the parent rather than the parent's reference point. The following
2853 example shows the difference:
2857 @lilypond[verbatim,quote]
2863 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
2865 @c Cannot document as they do not seem to operate consistently on all objects -td
2866 @c TODO investigate further
2870 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
2872 @node Using the @code{break-aligned-interface}
2873 @unnumberedsubsubsec Using the @code{break-aligned-interface}
2875 Rehearsal marks may be aligned with notation objects other
2876 than bar lines. These objects include @code{ambitus},
2877 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
2878 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
2879 @code{time-signature}.
2881 By default, rehearsal marks will be horizontally centered above the
2884 @lilypond[verbatim,quote,relative=1]
2886 % the RehearsalMark will be centered above the Clef
2887 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
2892 % the RehearsalMark will be centered above the TimeSignature
2893 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
2901 The alignment of the rehearsal mark relative to the notation object
2902 can be changed, as shown in the following example. In a score with
2903 multiple staves, this setting should be done for all the staves.
2905 @lilypond[verbatim,quote,relative=1]
2906 % The RehearsalMark will be centered above the KeySignature
2907 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
2913 % The RehearsalMark will be aligned with the left edge of the KeySignature
2914 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
2918 % The RehearsalMark will be aligned with the right edge of the KeySignature
2919 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
2925 The rehearsal mark can also be offset to the right or left of the left edge
2926 by an arbitrary amount. The units are staff-spaces:
2928 @lilypond[verbatim,quote,relative=1]
2929 % The RehearsalMark will be aligned with the left edge of the KeySignature
2930 % and then shifted right by 3.5 staff-spaces
2931 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
2932 \once \override Score.KeySignature #'break-align-anchor = #3.5
2936 % The RehearsalMark will be aligned with the left edge of the KeySignature
2937 % and then shifted left by 2 staff-spaces
2938 \once \override Score.KeySignature #'break-align-anchor = #-2
2946 @node Vertical grouping of grobs
2947 @subsection Vertical grouping of grobs
2949 @c FIXME Expand this section
2951 The VerticalAlignment and VerticalAxisGroup grobs work together.
2952 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
2953 etc. VerticalAlignment then vertically aligns the different grobs
2954 grouped together by VerticalAxisGroup. There is usually only one
2955 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
2959 @node Modifying stencils
2960 @subsection Modifying stencils
2962 All layout objects have a @code{stencil} property which is part of
2963 the @code{grob-interface}. By default, this property is usually
2964 set to a function specific to the object that is tailor-made to
2965 render the symbol which represents it in the output. For example,
2966 the standard setting for the @code{stencil} property of the
2967 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
2969 The standard symbol for any object can be replaced by modifying the
2970 @code{stencil} property to reference a different, specially-written,
2971 procedure. This requires a high level of knowledge of the internal
2972 workings of LilyPond, but there is an easier way which can often
2973 produce adequate results.
2975 This is to set the @code{stencil} property to the procedure which
2976 prints text -- @code{ly:text-interface::print} -- and to add a
2977 @code{text} property to the object which is set to contain the
2978 markup text which produces the required symbol. Due to the
2979 flexibility of markup, much can be achieved -- see in particular
2980 @ref{Graphic notation inside markup}.
2982 The following example demonstrates this by changing the note head
2983 symbol to a cross within a circle.
2985 @lilypond[verbatim,quote]
2987 \once \override NoteHead #'stencil = #ly:text-interface::print
2988 \once \override NoteHead #'text = \markup {
2990 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
2991 \musicglyph #"noteheads.s2cross"
2999 Any of the glyphs in the feta Font can be supplied to the
3000 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3002 @c TODO Add inserting eps files or ref to later
3004 @c TODO Add inserting Postscript or ref to later
3009 @ref{Graphic notation inside markup},
3010 @ref{Formatting text},
3011 @ref{Text markup commands},
3012 @ref{The Feta font}.
3015 @node Modifying shapes
3016 @subsection Modifying shapes
3019 * Modifying ties and slurs::
3022 @node Modifying ties and slurs
3023 @unnumberedsubsubsec Modifying ties and slurs
3025 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3026 curves. If the shape of the tie or slur which is calculated
3027 automatically is not optimum, the shape may be modified manually by
3028 explicitly specifying the four control points required to define
3029 a third-order Bézier curve.
3031 Third-order or cubic Bézier curves are defined by four control
3032 points. The first and fourth control points are precisely the
3033 starting and ending points of the curve. The intermediate two
3034 control points define the shape. Animations showing how the curve
3035 is drawn can be found on the web, but the following description
3036 may be helpful. The curve starts from the first control point
3037 heading directly towards the second, gradually bending over to
3038 head towards the third and continuing to bend over to head towards
3039 the fourth, arriving there travelling directly from the third
3040 control point. The curve is entirely contained in the
3041 quadrilateral defined by the four control points.
3043 Here is an example of a case where the tie is not optimum, and
3044 where @code{\tieDown} would not help.
3046 @lilypond[verbatim,quote,relative=1]
3050 { r4 <g c,> <g c,> <g c,> }
3054 One way of improving this tie is to manually modify its control
3057 The coordinates of the Bézier control points are specified in units
3058 of staff-spaces. The X@tie{}coordinate is relative to the reference
3059 point of the note to which the tie or slur is attached, and the
3060 Y@tie{}coordinate is relative to the staff center line. The
3061 coordinates are entered as a list of four pairs of decimal numbers
3062 (reals). One approach is to estimate the coordinates of the two
3063 end points, and then guess the two intermediate points. The optimum
3064 values are then found by trial and error.
3066 It is useful to remember that a symmetric curve requires symmetric
3067 control points, and that Bézier curves have the useful property that
3068 transformations of the curve such as translation, rotation and
3069 scaling can be achieved by applying the same transformation to the
3070 curve's control points.
3072 For the example above the following override gives a satisfactory
3075 @lilypond[verbatim,quote,relative=1]
3078 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3081 { r4 <g c,> <g c,> <g c,>4 }
3087 It is not possible to modify shapes of ties or slurs by changing
3088 the @code{control-points} property if there are more than one at
3089 the same musical moment, not even by using the @code{\tweak}