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 @funindex alignAboveContext
786 @funindex alignBelowContext
788 @lilypond[quote,ragged-right]
791 \relative c' \new Staff = "main" {
794 \new Staff \with {alignAboveContext=main} \ossia
801 @cindex nested contexts
802 @cindex contexts, nested
807 Contexts like @code{PianoStaff} can contain other contexts
808 nested within them. Contexts which are acceptable for nesting
809 are defined by the @qq{accepts} list of a context. Contexts
810 which are not in this list are placed below the outer context
811 in the printed score.
812 For example, the @code{PianoStaff} context is defined by default
813 to accept @code{Staff} and @code{FiguredBass} contexts within
814 it, but not (for example) a @code{Lyrics} context. So in the
815 following structure the lyrics are placed below the piano staff
816 rather than between the two staves:
818 @lilypond[verbatim,quote,relative=1]
821 \new Staff { e4 d c2 }
822 \addlyrics { Three blind mice }
830 The @qq{accepts} list of a context can be modified to include
831 additional nested contexts, so if we wanted the lyrics to appear
832 between the two staves we could use:
834 @lilypond[verbatim,quote,relative=1]
835 \new PianoStaff \with { \accepts Lyrics }
837 \new Staff { e4 d c2 }
838 \addlyrics { Three blind mice }
846 The opposite of @code{\accepts} is @code{\denies}; this removes a
847 context from the @qq{accepts} list.
849 @node Explaining the Internals Reference
850 @section Explaining the Internals Reference
854 * Navigating the program reference::
855 * Layout interfaces::
856 * Determining the grob property::
857 * Naming conventions::
860 @node Navigating the program reference
861 @subsection Navigating the program reference
863 @c TODO remove this (it's in the LM)
864 @c Replace with more factual directions
866 Suppose we want to move the fingering indication in the fragment
869 @lilypond[quote,fragment,relative=2,verbatim]
875 If you visit the documentation on fingering instructions (in
876 @ref{Fingering instructions}), you will notice:
881 Internals Reference: @rinternals{Fingering}.
886 @c outdated info; probably will delete.
888 This fragment points to two parts of the program reference: a page
889 on @code{FingeringEvent} and one on @code{Fingering}.
891 The page on @code{FingeringEvent} describes the properties of the music
892 expression for the input @code{-2}. The page contains many links
893 forward. For example, it says
896 Accepted by: @rinternals{Fingering_engraver},
900 That link brings us to the documentation for the Engraver, the
904 This engraver creates the following layout objects: @rinternals{Fingering}.
907 In other words, once the @code{FingeringEvent}s are interpreted, the
908 @code{Fingering_engraver} plug-in will process them.
912 @c I can't figure out what this is supposed to mean. -gp
914 The @code{Fingering_engraver} is also listed to create
915 @rinternals{Fingering} objects,
917 @c old info? it doesn't make any sense to me with our current docs.
919 second bit of information listed under @b{See also} in the Notation
924 The programmer's reference is available as an HTML document. It is
925 highly recommended that you read it in HTML form, either online or
926 by downloading the HTML documentation. This section will be much more
927 difficult to understand if you are using the
931 Follow the link to @rinternals{Fingering}. At the top of the
935 Fingering objects are created by: @rinternals{Fingering_engraver} and
936 @rinternals{New_fingering_engraver}.
939 By following related links inside the program reference, we can follow the
940 flow of information within the program:
944 @item @rinternals{Fingering}:
945 @rinternals{Fingering} objects are created by:
946 @rinternals{Fingering_engraver}
948 @item @rinternals{Fingering_engraver}:
949 Music types accepted: @rinternals{fingering-event}
951 @item @rinternals{fingering-event}:
952 Music event type @code{fingering-event} is in Music expressions named
953 @rinternals{FingeringEvent}
956 This path goes against the flow of information in the program: it
957 starts from the output, and ends at the input event. You could
958 also start at an input event, and read with the flow of
959 information, eventually ending up at the output object(s).
961 The program reference can also be browsed like a normal document. It
964 @rinternals{Music definitions},
967 @code{Music definitions}
969 on @rinternals{Translation}, and the @rinternals{Backend}. Every
970 chapter lists all the definitions used and all properties that may be
974 @node Layout interfaces
975 @subsection Layout interfaces
977 @cindex interface, layout
978 @cindex layout interface
981 The HTML page that we found in the previous section describes the
982 layout object called @rinternals{Fingering}. Such an object is a
983 symbol within the score. It has properties that store numbers (like
984 thicknesses and directions), but also pointers to related objects. A
985 layout object is also called a @emph{Grob}, which is short for Graphical
986 Object. For more details about Grobs, see @rinternals{grob-interface}.
988 The page for @code{Fingering} lists the definitions for the
989 @code{Fingering} object. For example, the page says
992 @code{padding} (dimension, in staff space):
998 which means that the number will be kept at a distance of at least 0.5
1002 Each layout object may have several functions as a notational or
1003 typographical element. For example, the Fingering object
1004 has the following aspects
1008 Its size is independent of the horizontal spacing, unlike slurs or beams.
1011 It is a piece of text. Granted, it is usually a very short text.
1014 That piece of text is typeset with a font, unlike slurs or beams.
1017 Horizontally, the center of the symbol should be aligned to the
1018 center of the note head.
1021 Vertically, the symbol is placed next to the note and the staff.
1024 The vertical position is also coordinated with other superscript
1025 and subscript symbols.
1028 Each of these aspects is captured in so-called @emph{interface}s,
1029 which are listed on the @rinternals{Fingering} page at the bottom
1032 This object supports the following interfaces:
1033 @rinternals{item-interface},
1034 @rinternals{self-alignment-interface},
1035 @rinternals{side-position-interface}, @rinternals{text-interface},
1036 @rinternals{text-script-interface}, @rinternals{font-interface},
1037 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1040 Clicking any of the links will take you to the page of the respective
1041 object interface. Each interface has a number of properties. Some of
1042 them are not user-serviceable (@q{Internal properties}), but others
1045 We have been talking of @emph{the} @code{Fingering} object, but actually it
1046 does not amount to much. The initialization file (see
1047 @rlearning{Other sources of information})
1048 @file{scm/@/define@/-grobs@/.scm} shows the soul of the @q{object},
1053 (avoid-slur . around)
1054 (slur-padding . 0.2)
1055 (staff-padding . 0.5)
1056 (self-alignment-X . 0)
1057 (self-alignment-Y . 0)
1058 (script-priority . 100)
1059 (stencil . ,ly:text-interface::print)
1060 (direction . ,ly:script-interface::calc-direction)
1061 (font-encoding . fetaNumber)
1062 (font-size . -5) ; don't overlap when next to heads.
1063 (meta . ((class . Item)
1064 (interfaces . (finger-interface
1066 text-script-interface
1068 side-position-interface
1069 self-alignment-interface
1070 item-interface))))))
1074 As you can see, the @code{Fingering} object is nothing more than a
1075 bunch of variable settings, and the webpage in the Internals Reference
1076 is directly generated from this definition.
1079 @node Determining the grob property
1080 @subsection Determining the grob property
1082 @c TODO remove this (it's in the LM)
1083 @c Replace with more factual directions
1085 Recall that we wanted to change the position of the @b{2} in
1087 @lilypond[quote,fragment,relative=2,verbatim]
1093 Since the @b{2} is vertically positioned next to its note, we have to
1094 meddle with the interface associated with this positioning. This is
1095 done using @code{side-position-interface}. The page for this interface
1099 @code{side-position-interface}
1101 Position a victim object (this one) next to other objects (the
1102 support). The property @code{direction} signifies where to put the
1103 victim object relative to the support (left or right, up or down?)
1108 Below this description, the variable @code{padding} is described as
1113 (dimension, in staff space)
1115 Add this much extra space between objects that are next to each other.
1119 By increasing the value of @code{padding}, we can move the
1120 fingering away from the note head. The following command inserts
1121 3 staff spaces of white
1122 between the note and the fingering:
1124 \once \override Voice.Fingering #'padding = #3
1127 Inserting this command before the Fingering object is created,
1128 i.e., before @code{c2}, yields the following result:
1130 @lilypond[quote,relative=2,fragment,verbatim]
1131 \once \override Voice.Fingering #'padding = #3
1138 In this case, the context for this tweak is @code{Voice}. This
1139 fact can also be deduced from the program reference, for the page for
1140 the @rinternals{Fingering_engraver} plug-in says
1143 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1147 @node Naming conventions
1148 @subsection Naming conventions
1150 Another thing that is needed, is an overview of the various naming
1153 scheme functions: lowercase-with-hyphens (incl. one-word
1155 scheme functions: ly:plus-scheme-style
1156 music events, music classes and music properties:
1158 Grob interfaces: scheme-style
1159 backend properties: scheme-style (but X and Y!)
1160 contexts (and MusicExpressions and grobs): Capitalized or
1162 context properties: lowercaseFollowedByCamelCase
1164 Capitalized_followed_by_lowercase_and_with_underscores
1166 Which of these are conventions and which are rules?
1167 Which are rules of the underlying language, and which are
1171 @node Modifying properties
1172 @section Modifying properties
1174 @c TODO change the menu and subsection node names to use
1175 @c backslash once the new macro to handle the refs
1176 @c is available. Need to find and change all refs at
1177 @c the same time. -td
1180 * Overview of modifying properties::
1182 * The override command::
1183 * The tweak command::
1184 * set versus override::
1188 @node Overview of modifying properties
1189 @subsection Overview of modifying properties
1191 Each context is responsible for creating certain types of graphical
1192 objects. The settings used for printing these objects are also stored by
1193 context. By changing these settings, the appearance of objects can be
1196 The syntax for this is
1199 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1202 Here @var{name} is the name of a graphical object, like
1203 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1204 variable of the formatting system (@q{grob property} or @q{layout
1205 property}). The latter is a symbol, so it must be quoted. The
1206 subsection @ref{Modifying properties}, explains what to fill in
1207 for @var{name}, @var{property}, and @var{value}. Here we only
1208 discuss the functionality of this command.
1213 \override Staff.Stem #'thickness = #4.0
1217 makes stems thicker (the default is 1.3, with staff line thickness as a
1218 unit). Since the command specifies @code{Staff} as context, it only
1219 applies to the current staff. Other staves will keep their normal
1220 appearance. Here we see the command in action:
1222 @lilypond[quote,verbatim,relative=2,fragment]
1224 \override Staff.Stem #'thickness = #4.0
1230 The @code{\override} command changes the definition of the @code{Stem}
1231 within the current @code{Staff}. After the command is interpreted
1232 all stems are thickened.
1234 Analogous to @code{\set}, the @var{context} argument may be left out,
1235 causing the default context @code{Voice} to be used. Adding
1236 @code{\once} applies the change during one timestep only.
1238 @lilypond[quote,fragment,verbatim,relative=2]
1240 \once \override Stem #'thickness = #4.0
1245 The @code{\override} must be done before the object is
1246 started. Therefore, when altering @emph{Spanner} objects such as slurs
1247 or beams, the @code{\override} command must be executed at the moment
1248 when the object is created. In this example,
1250 @lilypond[quote,fragment,verbatim,relative=2]
1251 \override Slur #'thickness = #3.0
1253 \override Beam #'thickness = #0.6
1258 the slur is fatter but the beam is not. This is because the command for
1259 @code{Beam} comes after the Beam is started, so it has no effect.
1261 Analogous to @code{\unset}, the @code{\revert} command for a context
1262 undoes an @code{\override} command; like with @code{\unset}, it only
1263 affects settings that were made in the same context. In other words, the
1264 @code{\revert} in the next example does not do anything.
1267 \override Voice.Stem #'thickness = #4.0
1268 \revert Staff.Stem #'thickness
1271 Some tweakable options are called @q{subproperties} and reside inside
1272 properties. To tweak those, use commands of the form
1274 @c leave this as a long long
1276 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1283 \override Stem #'details #'beamed-lengths = #'(4 4 3)
1289 Internals: @rinternals{OverrideProperty}, @rinternals{RevertProperty},
1290 @rinternals{PropertySet}, @rinternals{Backend}, and
1291 @rinternals{All layout objects}.
1296 The back-end is not very strict in type-checking object properties.
1297 Cyclic references in Scheme values for properties can cause hangs
1298 or crashes, or both.
1302 @node The set command
1303 @subsection The @code{\set} command
1307 @cindex changing properties
1309 Each context can have different @emph{properties}, variables contained
1310 in that context. They can be changed during the interpretation step.
1311 This is achieved by inserting the @code{\set} command in the music,
1314 \set @var{context}.@var{prop} = #@var{value}
1318 @lilypond[quote,verbatim,relative=2,fragment]
1320 \set Score.skipBars = ##t
1324 This command skips measures that have no notes. The result is that
1325 multi-rests are condensed. The value assigned is a Scheme object. In
1326 this case, it is @code{#t}, the boolean True value.
1328 If the @var{context} argument is left out, then the current bottom-most
1329 context (typically @code{ChordNames}, @code{Voice}, or
1330 @code{Lyrics}) is used. In this example,
1332 @lilypond[quote,verbatim,relative=2,fragment]
1334 \set autoBeaming = ##f
1339 the @var{context} argument to @code{\set} is left out, so automatic
1340 beaming is switched off in the current @rinternals{Voice}. Note that
1341 the bottom-most context does not always contain the property that you
1342 wish to change -- for example, attempting to set the @code{skipBars}
1343 property (of the bottom-most context, in this case @code{Voice}) will
1346 @lilypond[quote,verbatim,relative=2,fragment]
1352 Contexts are hierarchical, so if a bigger context was specified, for
1353 example @code{Staff}, then the change would also apply to all
1354 @code{Voice}s in the current stave. The change is applied
1355 @q{on-the-fly}, during the music, so that the setting only affects the
1356 second group of eighth notes.
1360 There is also an @code{\unset} command,
1362 \unset @var{context}.@var{prop}
1366 which removes the definition of @var{prop}. This command removes
1367 the definition only if it is set in @var{context}, so
1370 \set Staff.autoBeaming = ##f
1374 introduces a property setting at @code{Staff} level. The setting also
1375 applies to the current @code{Voice}. However,
1378 \unset Voice.autoBeaming
1382 does not have any effect. To cancel this setting, the @code{\unset}
1383 must be specified on the same level as the original @code{\set}. In
1384 other words, undoing the effect of @code{Staff.autoBeaming = ##f}
1387 \unset Staff.autoBeaming
1390 Like @code{\set}, the @var{context} argument does not have to be
1391 specified for a bottom context, so the two statements
1394 \set Voice.autoBeaming = ##t
1395 \set autoBeaming = ##t
1403 Settings that should only apply to a single time-step can be entered
1404 with @code{\once}, for example in
1406 @lilypond[quote,verbatim,relative=2,fragment]
1408 \once \set fontSize = #4.7
1413 the property @code{fontSize} is unset automatically after the second
1416 A full description of all available context properties is in the
1417 program reference, see
1419 @rinternals{Tunable context properties}.
1422 Translation @expansion{} Tunable context properties.
1427 @node The override command
1428 @subsection The @code{\override} command
1430 Commands which change output generally look like
1433 \override Voice.Stem #'thickness = #3.0
1437 To construct this tweak we must determine these bits of information:
1440 @item the context: here @code{Voice}.
1441 @item the layout object: here @code{Stem}.
1442 @item the layout property: here @code{thickness}.
1443 @item a sensible value: here @code{3.0}.
1446 Some tweakable options are called @q{subproperties} and reside inside
1447 properties. To tweak those, use commands in the form
1450 \override Stem #'details #'beamed-lengths = #'(4 4 3)
1453 @cindex internal documentation
1454 @cindex finding graphical objects
1455 @cindex graphical object descriptions
1458 @cindex internal documentation
1460 For many properties, regardless of the data type of the property, setting the
1461 property to false ( @code{##f} ) will result in turning it off, causing
1462 LilyPond to ignore that property entirely. This is particularly useful for
1463 turning off grob properties which may otherwise be causing problems.
1465 We demonstrate how to glean this information from the notation manual
1466 and the program reference.
1469 @node The tweak command
1470 @subsection The @code{\tweak} command
1475 In some cases, it is possible to take a short-cut for tuning
1476 graphical objects. For objects that are created directly from
1477 an item in the input file, you can use the @code{\tweak} command.
1480 @lilypond[relative=2,verbatim]
1485 \tweak #'duration-log #1
1488 -\tweak #'padding #8
1492 @cindex chord, modifying one note in
1494 But the main use of the @code{\tweak} command is to modify just
1495 one of a number of notation elements which start at the same musical
1496 moment, like the notes of a chord, or tuplet brackets which start
1499 For an introduction to the syntax and uses of the tweak command
1500 see @rlearning{Tweaking methods}.
1502 The @code{\tweak} command sets a property in the following object
1503 directly, without requiring the grob name or context to be
1504 specified. For this to work, it is necessary for the @code{\tweak}
1505 command to remain immediately adjacent to the object to which it is
1506 to apply after the input file has been converted to a music stream.
1507 This is often not the case, as many additional elements are inserted
1508 into the music stream implicitly. For example, when a note which is
1509 not part of a chord is processed, Lilypond implicitly inserts a
1510 @code{ChordEvent} event before the note, so separating the tweak
1511 from the note. However, if chord symbols are placed round the
1512 tweak and the note, the @code{\tweak} command comes after the
1513 @code{ChordEvent} in the music stream, so remaining adjacent to the
1514 note, and able to modify it.
1518 @lilypond[relative=2,verbatim,quote]
1519 <\tweak #'color #red c>4
1525 @lilypond[relative=2,verbatim,quote]
1526 \tweak #'color #red c4
1529 When several similar items are placed at the same musical moment,
1530 the @code{\override} command cannot be used to modify just one of
1531 them -- this is where the @code{\tweak} command must be used.
1532 Items which may appear more than once at the same musical moment
1533 include the following:
1535 @c TODO expand to include any further uses of \tweak
1537 @item note heads of notes inside a chord
1538 @item articulation signs on a single note
1539 @item ties between notes in a chord
1540 @item tuplet brackets starting at the same time
1543 @c TODO add examples of these
1546 and @code{\tweak} may be used to modify any single occurrence of
1549 Notably the @code{\tweak} command cannot be used to modify stems,
1550 beams or accidentals, since these are generated later by note heads,
1551 rather than by music elements in the input stream. Nor can a
1552 @code{\tweak} command be used to modify clefs or time signatures,
1553 since these become separated from any preceding @code{\tweak}
1554 command in the input stream by the automatic insertion of extra
1555 elements required to specify the context.
1557 But the @code{\tweak} command can be used as an alternative to
1558 the @code{\override} command to modify those notational elements
1559 that do not cause any additional implicit elements to be added
1560 before them in the music stream. For example, slurs may be
1561 modified in this way:
1563 @lilypond[verbatim,quote,relative=1]
1564 c-\tweak #'thickness #5 ( d e f)
1567 Also several @code{\tweak} commands may be placed before a
1568 notational element -- all affect it:
1570 @lilypond[verbatim,quote,relative=1]
1572 -\tweak #'style #'dashed-line
1573 -\tweak #'dash-fraction #0.2
1574 -\tweak #'thickness #3
1575 -\tweak #'color #red
1580 The music stream which is generated from a section of an input file,
1581 including any automatically inserted elements, may be examined,
1582 see @ref{Displaying music expressions}. This may be helpful in
1583 determining what may be modified by a @code{\tweak} command.
1588 @rlearning{Tweaking methods}.
1591 @ref{Displaying music expressions}.
1595 @cindex tweaks in a variable
1596 The @code{\tweak} command cannot be used inside a variable.
1598 @cindex tweaks in lyrics
1599 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1601 @cindex tweaking control points
1602 @cindex control points, tweaking
1604 The @code{\tweak} command cannot be used to modify the control
1605 points of just one of several ties in a chord, other than the first
1606 one encountered in the input file.
1608 @node set versus override
1609 @subsection @code{\set} vs. @code{\override}
1611 We have seen two methods of changing properties: @code{\set} and
1612 @code{\override}. There are actually two different kinds of
1615 Contexts can have properties, which are usually named in
1616 @code{studlyCaps}. They mostly control the translation from
1617 music to notation, eg. @code{localKeySignature} (for determining
1618 whether to print accidentals), @code{measurePosition} (for
1619 determining when to print a bar line). Context properties can
1620 change value over time while interpreting a piece of music;
1621 @code{measurePosition} is an obvious example of
1622 this. Context properties are modified with @code{\set}.
1624 There is a special type of context property: the element
1625 description. These properties are named in @code{StudlyCaps}
1626 (starting with capital letters). They contain the
1627 @q{default settings} for said graphical object as an
1628 association list. See @file{scm/@/define@/-grobs@/.scm}
1629 to see what kind of settings there are. Element descriptions
1630 may be modified with @code{\override}.
1632 @code{\override} is actually a shorthand;
1635 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1639 is more or less equivalent to
1641 @c leave this long line -gp
1643 \set @var{context}.@var{name} #'@var{property} = #(cons (cons '@var{property} @var{value}) <previous value of @var{context})
1646 The value of @code{context} (the alist) is used to initialize
1647 the properties of individual grobs. Grobs also have
1648 properties, named in Scheme style, with
1649 @code{dashed-words}. The values of grob properties change
1650 during the formatting process: formatting basically amounts
1651 to computing properties using callback functions.
1653 @code{fontSize} is a special property: it is equivalent to
1654 entering @code{\override ... #'font-size} for all pertinent
1655 objects. Since this is a common change, the special
1656 property (modified with @code{\set}) was created.
1659 @node Useful concepts and properties
1660 @section Useful concepts and properties
1665 * Direction and placement::
1666 * Distances and measurements::
1667 * Staff symbol properties::
1669 * Visibility of objects::
1671 * Rotating objects::
1675 @subsection Input modes
1677 The way in which the notation contained within an input file is
1678 interpreted is determined by the current input mode.
1682 This is activated with the @code{\chordmode} command, and causes
1683 input to be interpreted with the syntax of chord notation, see
1684 @ref{Chord notation}. Chords are rendered as notes on a staff.
1686 Chord mode is also activated with the @code{\chords} command.
1687 This also creates a new @code{ChordNames} context and
1688 causes the following input to be interpreted with the syntax of
1689 chord notation and rendered as chord names in the @code{ChordNames}
1690 context, see @ref{Printing chord names}.
1694 This is activated with the @code{\drummode} command, and causes
1695 input to be interpreted with the syntax of drum notation, see
1696 @ref{Basic percussion notation}.
1698 Drum mode is also activated with the @code{\drums} command.
1699 This also creates a new @code{DrumStaff} context and causes the
1700 following input to be interpreted with the syntax of drum notation
1701 and rendered as drum symbols on a drum staff, see @ref{Basic
1702 percussion notation}.
1704 @strong{Figure mode}
1706 This is activated with the @code{\figuremode} command, and causes
1707 input to be interpreted with the syntax of figured bass, see
1708 @ref{Entering figured bass}.
1710 Figure mode is also activated with the @code{\figures} command.
1711 This also creates a new @code{FiguredBass} context and causes the
1712 following input to be interpreted with the figured bass syntax
1713 and rendered as figured bass symbols in the @code{FiguredBass}
1714 context, see @ref{Introduction to figured bass}.
1716 @strong{Fret and tab modes}
1718 There are no special input modes for entering fret and tab symbols.
1720 To create tab diagrams, enter notes or chords in note mode and
1721 render them in a @code{TabStaff} context, see
1722 @ref{Default tablatures}.
1724 To create fret diagrams above a staff, you have two choices.
1725 You can either use the @code{FretBoards} context (see
1726 @ref{Automatic fret diagrams} or you can enter them as a markup
1727 above the notes using the @code{\fret-diagram} command (see
1728 @ref{Fret diagram markups}).
1730 @strong{Lyrics mode}
1732 This is activated with the @code{\lyricmode} command, and causes
1733 input to be interpreted as lyric syllables with optional durations
1734 and associated lyric modifiers, see @ref{Vocal music}.
1736 Lyric mode is also activated with the @code{\addlyrics} command.
1737 This also creates a new @code{Lyrics} context and an implicit
1738 @code{\lyricsto} command which associates the following lyrics
1739 with the preceding music.
1741 @strong{Markup mode}
1743 This is activated with the @code{\markup} command, and causes
1744 input to be interpreted with the syntax of markup, see
1745 @ref{Text markup commands}.
1747 @c silly work-around for texinfo broken-ness
1748 @c (@strong{Note...} causes a spurious cross-reference in Info)
1751 This is the default mode or it may be activated with the
1752 @code{\notemode} command. Input is interpreted as pitches,
1753 durations, markup, etc and typeset as musical notation on a staff.
1755 It is not normally necessary to specify note mode explicitly, but
1756 it may be useful to do so in certain situations, for example if you
1757 are in lyric mode, chord mode or any other mode and want to insert
1758 something that only can be done with note mode syntax.
1760 For example, to indicate dynamic markings for the verses of a
1761 choral pieces it is necessary to enter note mode to interpret
1764 @lilypond[verbatim,relative=2,quote]
1767 \notemode{\set stanza = \markup{ \dynamic f 1. } }
1771 \notemode{\set stanza = \markup{ \dynamic p 2. } }
1778 @node Direction and placement
1779 @subsection Direction and placement
1781 In typesetting music the direction and placement of many items is
1782 a matter of choice. For example, the stems of notes can
1783 be directed up or down; lyrics, dynamics, and other expressive
1784 marks may be placed above or below the staff; text may be aligned
1785 left, right or center; etc. Most of these choices may be left to
1786 be determined automatically by LilyPond, but in some cases it may
1787 be desirable to force a particular direction or placement.
1789 @strong{Default actions}
1791 By default some directions are always up or always down (e.g.
1792 dynamics or fermata), while other things can alternate between
1793 up or down based on the stem direction (like slurs or accents).
1795 @c TODO Add table showing these
1797 @strong{Context layout order}
1799 Contexts are normally positioned in a system from top to bottom
1800 in the order in which they are encountered. Note, however, that
1801 a context will be created implicitly if a command is encountered
1802 when there is no suitable context available to contain it. When
1803 contexts are nested, the outer context will exclude inner contexts
1804 which are not included in its @qq{accepts} list; excluded contexts
1805 will be repositioned below the outer context.
1807 The default order in which contexts are laid out and the
1808 @qq{accepts} list can be changed, see @ref{Aligning contexts}.
1810 @strong{Articulation direction indicators}
1812 When adding articulations to notes the direction indicator,
1813 @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down}) or
1814 @code{-} (meaning @qq{use default direction}), can usually be
1815 omitted, in which case @code{-} is assumed. But a direction
1816 indicator is @strong{always} required before
1819 @item @code{\tweak} commands
1820 @item @code{\markup} commands
1821 @item @code{\tag} commands
1822 @item string markups, e.g. -"string"
1823 @item fingering instructions, e.g. @code{-1}
1824 @item articulation shortcuts, e.g. @code{-.}, @code{->}, @code{--}
1827 @strong{The direction property}
1829 The position or direction of many layout objects is controlled
1830 by the @code{direction} property.
1832 The value of the @code{direction} property may be
1833 set to @code{1}, meaning @qq{up} or @qq{above}, or to @code{-1},
1834 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
1835 @code{DOWN} may be used instead of @code{1} and @code{-1}
1836 respectively. The default direction may be specified by setting
1837 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
1838 in many cases predefined commands
1839 exist to specify the direction. These are all of the form
1842 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
1845 where @code{xxxNeutral} means @qq{use the default direction}.
1846 See @rlearning{Within-staff objects}.
1848 In a few cases, arpeggio being the only common example, the value
1849 of the @code{direction} property specifies whether the object
1850 is to be placed to the right or left of the parent object. In
1851 this case @code{-1} or @code{LEFT} means @qq{to the left} and
1852 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
1853 or @code{CENTER} means @qq{use the default} direction, as before.
1856 These all have side-axis set to #X
1857 AmbitusAccidental - direction has no effect
1859 StanzaNumber - not tried
1860 TrillPitchAccidental - not tried
1861 TrillPitchGroup - not tried
1866 @node Distances and measurements
1867 @subsection Distances and measurements
1869 @cindex distances, absolute
1870 @cindex distances, scaled
1877 Distances in LilyPond are of two types: absolute and scaled.
1879 Absolute distances are used for specifying margins, indents, and
1880 other page layout details, and are by default specified in
1881 millimeters. Distances may be specified in other units by
1882 following the quantity by @code{\mm}, @code{\cm},
1883 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27
1884 of an inch). Page layout distances can also be specified in
1885 scalable units (see the following paragraph) by appending
1886 @code{\staff-space} to the quantity.
1887 Page layout is described in detail in @ref{Page formatting}.
1889 Scaled distances are always specified in units of the staff-space
1890 or, rarely, the half staff-space. The staff-space is the distance
1891 between two adjacent staff lines. The default value can be changed
1892 globally by setting the global staff size, or it can be overridden
1893 locally by changing the @code{staff-space} property of
1894 @code{StaffSymbol}. Scaled distances automatically scale with any
1895 change to the either the global staff size or the
1896 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
1897 automatically only with changes to the global staff size.
1898 The global staff size thus enables the overall size of a rendered
1899 score to be easily varied. For the methods of setting the global
1900 staff size see @ref{Setting the staff size}.
1904 If just a section of a score needs to be rendered to a different
1905 scale, for example an ossia section or a footnote, the global staff
1906 size cannot simply be changed as this would affect the entire score.
1907 In such cases the change in size is made by overriding both the
1908 @code{staff-space} property of @code{StaffSymbol} and the size of
1909 the fonts. A Scheme function, @code{magstep}, is available to
1910 convert from a font size change to the equivalent change in
1911 @code{staff-space}. For an explanation and an example of its use,
1912 see @rlearning{Length and thickness of objects}.
1917 @rlearning{Length and thickness of objects}.
1920 @ref{Page formatting},
1921 @ref{Setting the staff size}.
1924 @node Staff symbol properties
1925 @subsection Staff symbol properties
1927 @cindex adjusting staff symbol
1928 @cindex drawing staff symbol
1929 @cindex staff symbol, setting of
1931 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
1932 @c Need to think of uses for these properties. Eg 'line-positions
1933 @c is used in a snippet to thicken centre line.
1934 @c If retained, add @ref to here in 1.6.2 -td
1936 The vertical position of staff lines and the number of staff lines
1937 can be defined at the same time. As the following example shows,
1938 note positions are not influenced by the staff line positions.
1940 @warning{The @code{'line-positions} property overrides the
1941 @code{'line-count} property. The number of staff lines is
1942 implicitly defined by the number of elements in the list of values
1943 for @code{'line-positions}.}
1945 @lilypond[verbatim,quote,relative=1]
1947 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
1952 The width of a staff can be modified. The units are staff
1953 spaces. The spacing of objects inside the staff is not affected by
1956 @lilypond[verbatim,quote,relative=1]
1958 \override StaffSymbol #'width = #23
1965 @subsection Spanners
1967 Many objects of musical notation extend over several notes or even
1968 several bars. Examples are slurs, beams, tuplet brackets, volta
1969 repeat brackets, crescendi, trills, and glissandi. Such objects
1970 are collectively called @qq{spanners}, and have special properties to control
1971 their appearance and behaviour. Some of these properties are common
1972 to all spanners; others are restricted to a sub-set of the spanners.
1974 All spanners support the @code{spanner-interface}. A few, esentially
1975 those that draw a straight line between the two objects, support in
1976 addition the @code{line-spanner-interface}.
1978 @unnumberedsubsubsec Using the @code{spanner-interface}
1980 This interface provides two properties that apply to several spanners.
1982 @strong{@i{The @code{minimum-length} property}}
1984 The minimum length of the spanner is specified by the
1985 @code{minimum-length} property. Increasing this usually has the
1986 necessary effect of increasing the spacing of the notes between the
1987 two end points. However, this override has no effect on
1988 many spanners, as their length is determined by other considerations.
1989 A few examples where it is effective are shown below.
1999 Works as long as callback is made:
2003 Works not at all for:
2012 @lilypond[verbatim,quote,relative=2]
2015 % increase the length of the tie
2016 -\tweak #'minimum-length #5
2020 @lilypond[verbatim,quote,relative=2]
2022 \compressFullBarRests
2024 % increase the length of the rest bar
2025 \once \override MultiMeasureRest #'minimum-length = #20
2030 @lilypond[verbatim,quote,relative=2]
2032 % increase the length of the hairpin
2033 \override Hairpin #'minimum-length = #20
2037 This override can also be used to increase the length of slurs and
2040 @lilypond[verbatim,quote,relative=2]
2043 -\tweak #'minimum-length #5
2048 -\tweak #'minimum-length #5
2052 For some layout objects, the @code{minimum-length} property becomes
2053 effective only if the @code{set-spacing-rods} procedure is called
2054 explicitly. To do this, the @code{springs-and-rods} property should
2055 be set to @code{ly:spanner::set-spacing-rods}. For example,
2056 the minimum length of a glissando has no effect unless the
2057 @code{springs-and-rods} property is set:
2059 @lilypond[verbatim,quote,relative=1]
2063 % not effective alone
2064 \once \override Glissando #'minimum-length = #20
2067 % effective only when both overrides are present
2068 \once \override Glissando #'minimum-length = #20
2069 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2073 The same is true of the @code{Beam} object:
2075 @lilypond[verbatim,quote,relative=1]
2076 % not effective alone
2077 \once \override Beam #'minimum-length = #20
2080 % effective only when both overrides are present
2081 \once \override Beam #'minimum-length = #20
2082 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2086 @strong{@i{The @code{to-barline} property}}
2088 The second useful property of the @code{spanner-interface} is
2089 @code{to-barline}. By default this is true, causing hairpins and
2090 other spanners which are terminated on the first note of a measure to
2091 end instead on the immediately preceding bar line. If set to false,
2092 the spanner will extend beyond the bar line and end on the note
2095 @lilypond[verbatim,quote,relative=2]
2096 a \< a a a a \! a a a \break
2097 \override Hairpin #'to-barline = ##f
2098 a \< a a a a \! a a a
2101 This property is not effective for all spanners. For example,
2102 seting it to @code{#t} has no effect on slurs or phrasing slurs
2103 or on other spanners for which terminating on the bar line would
2106 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2108 Objects which support the @code{line-spanner-interface} include
2111 @item @code{DynamicTextSpanner}
2112 @item @code{Glissando}
2113 @item @code{TextSpanner}
2114 @item @code{TrillSpanner}
2115 @item @code{VoiceFollower}
2118 The routine responsible for drawing the stencils for these spanners is
2119 @code{ly:line-interface::print}. This routine determines the
2120 exact location of the two end points and draws a line
2121 between them, in the style requested. The locations of the two
2122 end points of the spanner are computed on-the-fly, but it is
2123 possible to override their Y-coordinates. The
2124 properties which need to be specified are nested
2125 two levels down within the property hierarchy, but the syntax of
2126 the @code{\override} command is quite simple:
2128 @lilypond[relative=2,quote,verbatim]
2130 \once \override Glissando #'bound-details #'left #'Y = #3
2131 \once \override Glissando #'bound-details #'right #'Y = #-2
2135 The units for the @code{Y} property are @code{staff-space}s,
2136 with the center line of the staff being the zero point.
2137 For the glissando, this is the value for @code{Y} at the
2138 X-coordinate corresponding to the center point of each note head,
2139 if the line is imagined to be extended to there.
2141 If @code{Y} is not set, the value is computed from the vertical
2142 position of the corresponding attachment point of the spanner.
2144 In case of a line break, the values for the end points are
2145 specified by the @code{left-broken} and @code{right-broken}
2146 sub-lists of @code{bound-details}. For example:
2148 @lilypond[relative=2,ragged-right,verbatim,fragment]
2149 \override Glissando #'breakable = ##t
2150 \override Glissando #'bound-details #'right-broken #'Y = #-3
2151 c1 \glissando \break
2156 A number of further properties of the @code{left} and
2157 @code{right} sub-lists of the @code{bound-details} property
2158 may be modified in the same way as @code{Y}:
2162 This sets the Y-coordinate of the end point, in @code{staff-space}s
2163 offset from the staff center line. By default, it is the center of
2164 the bound object, so a glissando points to the vertical center of
2167 For horizontal spanners, such as text spanners and trill spanners,
2168 it is hardcoded to 0.
2171 This determines where the line starts and ends in the X-direction,
2172 relative to the bound object. So, a value of @code{-1} (or
2173 @code{LEFT}) makes the line start/end at the left side of the note
2174 head it is attached to.
2177 This is the absolute X-coordinate of the end point. It is usually
2178 computed on the fly, and overriding it has little useful effect.
2181 Line spanners may have symbols at the beginning or end, which is
2182 contained in this sub-property. This is for internal use; it is
2183 recommended that @code{text} be used instead.
2186 This is a markup that is evaluated to yield the stencil. It is used
2187 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2189 @lilypond[quote,ragged-right,fragment,relative=2,verbatim]
2190 \override TextSpanner #'bound-details #'left #'text
2191 = \markup { \small \bold Slower }
2192 c2\startTextSpan b c a\stopTextSpan
2195 @item stencil-align-dir-y
2196 @item stencil-offset
2197 Without setting one of these, the stencil is simply put at the
2198 end-point, centered on the line, as defined by the @code{X} and
2199 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2200 or @code{stencil-offset} will move the symbol at the edge vertically
2201 relative to the end point of the line:
2203 @lilypond[relative=1,fragment,verbatim]
2204 \override TextSpanner #'bound-details
2205 #'left #'stencil-align-dir-y = #-2
2206 \override TextSpanner #'bound-details
2207 #'right #'stencil-align-dir-y = #UP
2209 \override TextSpanner #'bound-details
2210 #'left #'text = #"ggg"
2211 \override TextSpanner #'bound-details
2212 #'right #'text = #"hhh"
2213 c4^\startTextSpan c c c \stopTextSpan
2216 Note that negative values move the text @emph{up}, contrary to the
2217 effect that might be expected, as a value of @code{-1} or
2218 @code{DOWN} means align the @emph{bottom} edge of the text with
2219 the spanner line. A value of @code{1} or @code{UP} aligns
2220 the top edge of the text with the spanner line.
2223 Setting this sub-property to @code{#t} produces an arrowhead at the
2227 This sub-property controls the space between the specified
2228 end point of the line and the actual end. Without padding, a
2229 glissando would start and end in the center of each note head.
2233 The music function @code{\endSpanners} terminates the spanner
2234 which starts on the immediately following note prematurely. It
2235 is terminated after exactly one note, or at the following bar line
2236 if @code{to-barline} is true and a bar line occurs before the next
2239 @lilypond[verbatim,quote,ragged-right,relative=2,fragment]
2241 c2 \startTextSpan c2 c2
2246 When using @code{\endSpanners} it is not necessary to close
2247 \startTextSpan with \stopTextSpan, nor is it necessary to close
2248 hairpins with @code{\!}.
2254 Internals Reference: @rinternals{TextSpanner},
2255 @rinternals{Glissando}, @rinternals{VoiceFollower},
2256 @rinternals{TrillSpanner},
2257 @rinternals{line-spanner-interface}.
2260 @node Visibility of objects
2261 @subsection Visibility of objects
2263 @cindex objects, visibility of
2264 @cindex grobs, visibility of
2265 @cindex visibility of objects
2267 There are four main ways in which the visibility of layout objects
2268 can be controlled: their stencil can be removed, they can be made
2269 transparent, they can be colored white, or their
2270 @code{break-visibility} property can be overridden. The first
2271 three apply to all layout objects; the last to just a few -- the
2272 @emph{breakable} objects. The Learning Manual introduces these
2273 four techniques, see @rlearning{Visibility and color of objects}.
2275 There are also a few other techniques which are specific to
2276 certain layout objects. These are covered under Special
2280 * Removing the stencil::
2281 * Making objects transparent::
2282 * Painting objects white::
2283 * Using break-visibility::
2284 * Special considerations::
2288 @node Removing the stencil
2289 @unnumberedsubsubsec Removing the stencil
2291 @cindex stencil, removing
2293 Every layout object has a stencil property. By default this is set
2294 to the specific function which draws that object. If this property
2295 is overridden to @code{#f} no function will be called and the object
2296 will not be drawn. The default action can be recovered with
2299 @lilypond[quote,verbatim,relative=1]
2301 \override Score.BarLine #'stencil = ##f
2303 \revert Score.BarLine #'stencil
2307 @node Making objects transparent
2308 @unnumberedsubsubsec Making objects transparent
2310 @cindex transparent, making objects
2312 Every layout object has a transparent property which by default is
2313 set to @code{#f}. If set to @code{#t} the object still occupies
2314 space but is made invisible.
2316 @lilypond[quote,verbatim,relative=2]
2318 \once \override NoteHead #'transparent = ##t
2322 @node Painting objects white
2323 @unnumberedsubsubsec Painting objects white
2325 @cindex objects, coloring
2326 @cindex coloring objects
2328 @cindex printing order
2329 @cindex overwriting objects
2330 @cindex objects, overwriting
2331 @cindex grobs, overwriting
2333 Every layout object has a color property which by default is set
2334 to @code{black}. If this is overridden to @code{white} the object
2335 will be indistinguishable from the white background. However,
2336 if the object crosses other objects the color of the crossing
2337 points will be determined by the order in which they are drawn,
2338 and this may leave a ghostly image of the white object, as shown
2341 @lilypond[quote,verbatim,relative=2]
2342 \override Staff.Clef #'color = #white
2346 This may be avoided by changing the order of printing the objects.
2347 All layout objects have a @code{layer} property which should be set
2348 to an integer. Objects with the lowest value of @code{layer} are
2349 drawn first, then objects with progressively higher values are drawn,
2350 so objects with higher values overwrite objects with lower values.
2351 By default most objects are assigned a @code{layer} value of
2352 @code{1}, although a few objects, including @code{StaffSymbol} and
2353 @code{BarLine}, are assigned a value of @code{0}. The order of
2354 printing objects with the same value of @code{layer} is indeterminate.
2356 In the example above the white clef, with a default @code{layer}
2357 value of @code{1}, is drawn after the staff lines (default
2358 @code{layer} value @code{0}), so overwriting them. To change this,
2359 the @code{Clef} object must be given in a lower value of
2360 @code{layer}, say @code{-1}, so that it is drawn earlier:
2362 @lilypond[quote,verbatim,relative=2]
2363 \override Staff.Clef #'color = #white
2364 \override Staff.Clef #'layer = #-1
2368 @node Using break-visibility
2369 @unnumberedsubsubsec Using break-visibility
2371 @c TODO Add making other objects breakable
2373 @cindex break-visibility
2375 Most layout objects are printed only once, but some like
2376 bar lines, clefs, time signatures and key signatures, may need
2377 to be printed twice when a line break occurs -- once at the end
2378 of the line and again at the start of the next line. Such
2379 objects are called @emph{breakable}, and have a property, the
2380 @code{break-visibility} property to control their visibility
2381 at the three positions in which they may appear -- at the
2382 start of a line, within a line if they are changed, and at the
2383 end of a line if a change takes place there.
2385 For example, the time signature
2386 by default will be printed at the start of the first line, but
2387 nowhere else unless it changes, when it will be printed at the
2388 point at which the change occurs. If this change occurs at the
2389 end of a line the new time signature will be printed at the start
2390 of the next line and a cautionary time signature will be printed
2391 at the end of the previous line as well.
2393 This behaviour is controlled by the @code{break-visibility}
2394 property, which is explained in
2395 @c Leave this ref on a newline - formats incorrectly otherwise -td
2396 @rlearning{Visibility and color of objects}. This property takes
2397 a vector of three booleans which, in order, determine whether the
2398 object is printed at the end of, within the body of, or at the
2399 beginning of a line. Or to be more precise, before a line break,
2400 where there is no line break, or after a line break.
2402 Alternatively, seven of the eight combinations may be specified
2403 by pre-defined functions, defined in @file{scm/output-lib.scm},
2404 where the last three columns indicate whether the layout objects
2405 will be visible in the positions shown at the head of the columns:
2407 @multitable @columnfractions .40 .15 .1 .1 .1
2408 @c TODO check these more carefully
2409 @headitem Function @tab Vector @tab Before @tab At no @tab After
2410 @headitem form @tab form @tab break @tab break @tab break
2412 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @ @ @tab no @tab no @tab no
2413 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2414 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2415 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2416 @c The center-visible function is not defined
2417 @c @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2418 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2419 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2420 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2423 The @code{center-visible} function is not pre-defined.
2425 The default settings of @code{break-visibility} depend on the
2426 layout object. The following table shows all the layout objects
2427 of interest which are affected by @code{break-visibility} and the
2428 default setting of this property:
2430 @multitable @columnfractions .3 .3 .4
2432 @headitem Layout object @tab Usual context @tab Default setting
2434 @c omit Ambitus as it appears not to be affected by break-visibility -td
2435 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2436 @item @code{BarLine} @tab @code{Score} @tab calculated
2437 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2438 @c omit the following item until it can be explained -td
2439 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2440 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2441 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2442 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2443 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2444 @c omit KeyCancellation until it can be explained -td
2445 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2446 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2447 @c omit LeftEdge until it can be explained -td
2448 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2449 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2450 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2451 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2455 The example below shows the use of the vector form to control the
2456 visibility of barlines:
2458 @lilypond[quote,verbatim,relative=1,ragged-right]
2461 % Remove bar line at the end of the current line
2462 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2468 Although all three components of the vector used to override
2469 @code{break-visibility} must be present, not all of them are
2470 effective with every layout object, and some combinations may
2471 even give errors. The following limitations apply:
2474 @item Bar lines cannot be printed at start of line.
2475 @item A bar number cannot be printed at the start of the first
2476 line unless it is set to be different from 1.
2477 @item Clef -- see below
2478 @item Double percent repeats are either all printed or all
2479 suppressed. Use begin-of line-invisible to print and
2480 all-invisible to suppress.
2481 @item Key signature -- see below
2482 @item OctavateEight -- see below
2485 @node Special considerations
2486 @unnumberedsubsubsec Special considerations
2488 @strong{@emph{Visibility following explicit changes}}
2490 @cindex key signature, visibility following explicit change
2491 @cindex explicitKeySignatureVisibility
2492 @cindex clef, visibility following explicit change
2493 @cindex explicitClefVisibility
2495 The @code{break-visibility} property controls the visibility of
2496 key signatures and changes of clef only at the start of lines,
2497 i.e. after a break. It has no effect on the visibility of the
2498 key signature or clef following an explicit key change or an
2499 explicit clef change within or at the end of a line. In the
2500 following example the key signature following the explicit change
2501 to B-flat major is still visible, even though @code{all-invisible}
2504 @lilypond[quote,verbatim,relative=1,ragged-right]
2507 % Try to remove all key signatures
2508 \override Staff.KeySignature #'break-visibility = #all-invisible
2516 The visibility of such explicit key signature and clef changes is
2517 controlled by the @code{explicitKeySignatureVisibility} and
2518 @code{explicitClefVisibility} properties. These are the equivalent
2519 of the @code{break-visibility} property and both take a vector of
2520 three booleans or the predefined functions listed above, exactly like
2521 @code{break-visibility}. Both are properties of the Staff context,
2522 not the layout objects themselves, and so they are set using the
2523 @code{\set} command. Both are set by default to @code{all-visible}.
2524 These properties control only the visibility of key signatures and
2525 clefs resulting from explicit changes and do not affect key
2526 signatures and clefs at the beginning of lines;
2527 @code{break-visibility} must still be overridden in the appropriate
2528 object to remove these.
2530 @lilypond[quote,verbatim,relative=1,ragged-right]
2533 \set Staff.explicitKeySignatureVisibility = #all-invisible
2534 \override Staff.KeySignature #'break-visibility = #all-invisible
2541 @strong{@emph{Visibility of cautionary accidentals}}
2543 To remove the cautionary accidentals printed at an explicit key
2544 change, set the Staff context property @code{printKeyCancellation}
2547 @lilypond[quote,verbatim,relative=1,ragged-right]
2550 \set Staff.explicitKeySignatureVisibility = #all-invisible
2551 \set Staff.printKeyCancellation = ##f
2552 \override Staff.KeySignature #'break-visibility = #all-invisible
2559 With these overrides only the accidentals before the notes remain
2560 to indicate the change of key.
2562 @c TODO Add visibility of cautionary accidentals before notes
2564 @strong{@emph{Automatic bars}}
2566 @cindex automaticBars
2567 @cindex bar lines, suppressing
2569 As a special case, the printing of bar lines can also be turned off
2570 by setting the @code{automaticBars} property in the Score context.
2571 If set to @code{#f}, bar lines will not be printed automatically;
2572 they must be explicitly created with a @code{\bar} command. Unlike
2573 the @code{\cadenzaOn} predefined command, measures are still counted.
2574 Bar generation will resume according to that count if this property
2575 is later set to @code{#t}. When set to @code{#f}, line breaks can
2576 occur only at explicit @code{\bar} commands.
2580 @strong{@emph{Octavated clefs}}
2582 @cindex octavated clefs, visibility of
2583 @cindex visibility of octavated clefs
2584 @cindex clefs, visibility of octavation
2586 The small octavation symbol on octavated clefs is produced by the
2587 @code{OctavateEight} layout object. Its visibility is controlled
2588 independently from that of the @code{Clef} object, so it is
2589 necessary to apply any required @code{break-visibility} overrides
2590 to both the @code{Clef} and the @code{OctavateEight} layout objects
2591 to fully suppress such clef symbols at the start of each line.
2593 For explicit clef changes, the @code{explicitClefVisibility}
2594 property controls both the clef symbol and any octavation symbol
2600 @rlearning{Visibility and color of objects}
2604 @subsection Line styles
2606 Some performance indications, e.g., @i{rallentando} and
2607 @i{accelerando} and @i{trills} are written as text and are
2608 extended over many measures with lines, sometimes dotted or wavy.
2610 These all use the same routines as the glissando for drawing the
2611 texts and the lines, and tuning their behavior is therefore also
2612 done in the same way. It is done with a spanner, and the routine
2613 responsible for drawing the spanners is
2614 @code{ly:line-interface::print}. This routine determines the
2615 exact location of the two @i{span points} and draws a line
2616 between them, in the style requested.
2618 Here is an example showing the different line styles available,
2619 and how to tune them.
2621 @lilypond[relative=2,ragged-right,verbatim,fragment]
2623 \once \override Glissando #'style = #'dashed-line
2625 \override Glissando #'style = #'dotted-line
2627 \override Glissando #'style = #'zigzag
2629 \override Glissando #'style = #'trill
2633 The locations of the end-points of the spanner are computed
2634 on-the-fly for every graphic object, but it is possible to
2638 @lilypond[relative=2,ragged-right,verbatim,fragment]
2640 \once \override Glissando #'bound-details #'right #'Y = #-2
2644 The value for @code{Y} is set to @code{-2} for the right end
2645 point. The left side may be similarly adjusted by specifying
2646 @code{left} instead of @code{right}.
2648 If @code{Y} is not set, the value is computed from the vertical
2649 position of the left and right attachment points of the spanner.
2651 Other adjustments of spanners are possible, for details, see
2654 @node Rotating objects
2655 @subsection Rotating objects
2657 Both layout objects and elements of markup text can be rotated by
2658 any angle about any point, but the method of doing so differs.
2661 * Rotating layout objects::
2665 @node Rotating layout objects
2666 @unnumberedsubsubsec Rotating layout objects
2668 @cindex rotating objects
2669 @cindex objects, rotating
2671 All layout objects which support the @code{grob-interface} can be
2672 rotated by setting their @code{rotation} property. This takes a
2673 list of three items: the angle of rotation counter-clockwise,
2674 and the x and y coordinates of the point relative to the object's
2675 reference point about which the rotation is to be performed. The
2676 angle of rotation is specified in degrees and the coordinates in
2679 The angle of rotation and the coordinates of the rotation point must
2680 be determined by trial and error.
2682 @cindex hairpins, angled
2683 @cindex angled hairpins
2685 There are only a few situations where the rotation of layout
2686 objects is useful; the following example shows one situation where
2689 @lilypond[quote,verbatim,relative=1]
2691 \override Hairpin #'rotation = #'(20 -1 0)
2695 @node Rotating markup
2696 @unnumberedsubsubsec Rotating markup
2698 All markup text can be rotated to lie at any angle by prefixing it
2699 with the @code{\rotate} command. The command takes two arguments:
2700 the angle of rotation in degrees counter-clockwise and the text to
2701 be rotated. The extents of the text are not rotated: they take
2702 their values from the extremes of the x and y coordinates of the
2703 rotated text. In the following example the
2704 @code{outside-staff-priority} property for text is set to @code{#f}
2705 to disable the automatic collision avoidance, which would push some
2706 of the text too high.
2708 @lilypond[quote,verbatim,relative=1]
2709 \override TextScript #'outside-staff-priority = ##f
2710 g4^\markup { \rotate #30 "a G" }
2711 b^\markup { \rotate #30 "a B" }
2712 des^\markup { \rotate #30 "a D-Flat" }
2713 fis^\markup { \rotate #30 "an F-Sharp" }
2716 @node Advanced tweaks
2717 @section Advanced tweaks
2719 This section discusses various approaches to fine tuning the
2720 appearance of the printed score.
2723 * Aligning objects::
2724 * Vertical grouping of grobs::
2725 * Modifying stencils::
2726 * Modifying shapes::
2732 @rlearning{Tweaking output},
2733 @rlearning{Other sources of information}.
2736 @ref{Explaining the Internals Reference},
2737 @ref{Modifying properties},
2738 @ref{Interfaces for programmers}.
2741 @file{scm/@/define@/-grobs@/.scm}.
2744 @rlsr{Tweaks and overrides}.
2746 Internals Reference:
2747 @rinternals{All layout objects}.
2749 @node Aligning objects
2750 @subsection Aligning objects
2752 Graphical objects which support the @code{self-alignment-interface} and/or
2753 the @code{side-position-interface} can be
2754 aligned to a previously placed object in a variety of ways. For a list of these objects, see
2755 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
2757 All graphical objects have a reference point, a horizontal extent and a
2758 vertical extent. The horizontal extent is a pair of numbers
2759 giving the displacements from the reference point of the left and
2760 right edges, displacements to the left being negative. The
2761 vertical extent is a pair of numbers giving the displacement from
2762 the reference point to the bottom and top edges, displacements down
2765 An object's position on a staff is given by the values of the
2766 @code{X-offset} and @code{Y-offset} properties. The value of
2767 @code{X-offset} gives the displacement from the x coordinate of
2768 the reference point of the parent object, and the value of
2769 @code{Y-offset} gives the displacement from the center line of the
2770 staff. The values of @code{X-offset} and
2771 @code{Y-offset} may be set directly or may be set to be calculated
2772 by procedures in order to achieve alignment with the parent object
2775 @warning{Many objects have special positioning considerations which
2776 cause any setting of @code{X-offset} or @code{Y-offset} to be
2777 ignored or modified, even though the object supports the
2778 @code{self-alignment-interface}.}
2780 For example, an accidental can be repositioned
2781 vertically by setting @code{Y-offset} but any changes to
2782 @code{X-offset} have no effect.
2784 Rehearsal marks may be aligned with
2785 breakable objects such as bar lines, clef symbols, time signature
2786 symbols and key signatures. There are special properties to be
2787 found in the @code{break-aligned-interface} for positioning rehearsal
2788 marks on such objects.
2791 * Setting @code{X-offset} and @code{Y-offset} directly::
2792 * Using the @code{side-position-interface}::
2793 * Using the @code{self-alignment-interface}::
2794 * Using the @code{break-aligned-interface}::
2797 @node Setting @code{X-offset} and @code{Y-offset} directly
2798 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
2800 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
2801 properties of many objects. The following example shows three
2802 notes with the default fingering position and the positions with @code{X-offset}
2803 and @code{Y-offset} modified.
2805 @lilypond[verbatim,quote,relative=2]
2808 -\tweak #'X-offset #0
2809 -\tweak #'Y-offset #0
2812 -\tweak #'X-offset #-1
2813 -\tweak #'Y-offset #1
2819 @node Using the @code{side-position-interface}
2820 @unnumberedsubsubsec Using the @code{side-position-interface}
2822 An object which supports the @code{side-position-interface} can be
2823 placed next to its parent object so that
2824 the specified edges of the two objects touch. The object may be
2825 placed above, below, to the right or to the left of the parent.
2826 The parent cannot be specified; it is determined by the order of
2827 elements in the input stream. Most objects have the associated
2828 note head as their parent.
2830 The values of the @code{side-axis} and @code{direction} properties
2831 determine where the object is to be placed, as follows:
2833 @c TODO add an example of each to the table
2835 @multitable @columnfractions .3 .3 .3
2836 @headitem @code{side-axis} @tab @code{direction} @tab
2837 @headitem property @tab property @tab Placement
2839 @item @code{0} @tab @code{-1} @tab left
2840 @item @code{0} @tab @code{1} @tab right
2841 @item @code{1} @tab @code{-1} @tab below
2842 @item @code{1} @tab @code{1} @tab above
2846 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
2847 the procedure @code{ly:side-position-interface::x-aligned-side}.
2848 This procedure will return the correct value of @code{X-offset} to
2849 place the object to the left or right side of the parent according
2850 to value of @code{direction}.
2852 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
2853 the procedure @code{ly:side-position-interface::y-aligned-side}.
2854 This procedure will return the correct value of @code{Y-offset} to
2855 place the object to the top or bottom of the parent according
2856 to value of @code{direction}.
2858 @c TODO Add examples
2860 @node Using the @code{self-alignment-interface}
2861 @unnumberedsubsubsec Using the @code{self-alignment-interface}
2863 @emph{Self-aligning objects horizontally}
2865 The horizontal alignment of an object which supports the
2866 @code{self-alignment-interface} is controlled by the value of
2867 the @code{self-alignment-X} property, provided the object's
2868 @code{X-offset} property is set to
2869 @code{ly:self-alignment-interface::x-aligned-on-self}.
2870 @code{self-alignment-X} may be given any
2871 real value, in units of half the total X extent of the
2872 object. Negative values move the object to the right, positive
2873 to the left. A value of @code{0} centers the object on the
2874 reference point of its parent, a value of @code{-1} aligns the
2875 left edge of the object on the reference point of its parent,
2876 and a value of @code{1} aligns the right edge of the object on the
2877 reference point of its parent. The symbols @code{LEFT},
2878 @code{CENTER} and @code{RIGHT} may be used instead of the values
2879 @code{-1, 0, 1} respectively.
2881 Normally the @code{\override} command would be used to modify the
2882 value of @code{self-alignment-X}, but the @code{\tweak} command
2883 can be used to separately align several annotations on a single
2886 @lilypond[quote,verbatim,relative=1]
2888 -\tweak #'self-alignment-X #-1
2890 -\tweak #'self-alignment-X #0
2892 -\tweak #'self-alignment-X #RIGHT
2894 -\tweak #'self-alignment-X #-2.5
2895 ^"aligned further to the right"
2898 @emph{Self-aligning objects vertically}
2900 Objects may be aligned vertically in an analogous way to aligning
2901 them horizontally if the @code{Y-offset} property is set to
2902 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
2903 other mechanisms are often involved in vertical alignment: the
2904 value of @code{Y-offset} is just one variable taken into account.
2905 This may make adjusting the value of some objects tricky.
2906 The units are just half the vertical extent of the object, which
2907 is usually quite small, so quite large numbers may be required.
2908 A value of @code{-1} aligns the lower edge of the object with
2909 the reference point of the parent object, a value of @code{0}
2910 aligns the center of the object with the reference point of the
2911 parent, and a value of @code{1} aligns the top edge of the object
2912 with the reference point of the parent. The symbols @code{DOWN},
2913 @code{CENTER}, @code{UP} may be substituted for @code{-1, 0, 1}
2916 @emph{Self-aligning objects in both directions}
2918 By setting both @code{X-offset} and @code{Y-offset}, an object may
2919 be aligned in both directions simultaneously.
2921 The following example shows how to adjust a fingering mark so
2922 that it nestles close to the note head.
2924 @lilypond[quote,verbatim,relative=2]
2926 -\tweak #'self-alignment-X #0.5 % move horizontally left
2927 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
2928 -\tweak #'self-alignment-Y #-1 % move vertically up
2933 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
2935 @c Cannot document as they do not seem to operate consistently on all objects -td
2936 @c TODO investigate further
2938 The @code{aligned-on-parent} procedures are used in the same way
2939 as the @code{aligned-on-self} procedures, they difference being
2940 that they permit an object to be aligned with the @emph{edges} of
2941 the parent rather than the parent's reference point. The following
2942 example shows the difference:
2946 @lilypond[verbatim,quote]
2952 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
2954 @c Cannot document as they do not seem to operate consistently on all objects -td
2955 @c TODO investigate further
2959 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
2961 @node Using the @code{break-aligned-interface}
2962 @unnumberedsubsubsec Using the @code{break-aligned-interface}
2964 Rehearsal marks may be aligned with notation objects other
2965 than bar lines. These objects include @code{ambitus},
2966 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
2967 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
2968 @code{time-signature}.
2970 By default, rehearsal marks will be horizontally centered above the
2973 @lilypond[verbatim,quote,relative=1]
2975 % the RehearsalMark will be centered above the Clef
2976 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
2981 % the RehearsalMark will be centered above the TimeSignature
2982 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
2990 The alignment of the rehearsal mark relative to the notation object
2991 can be changed, as shown in the following example. In a score with
2992 multiple staves, this setting should be done for all the staves.
2994 @lilypond[verbatim,quote,relative=1]
2995 % The RehearsalMark will be centered above the KeySignature
2996 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3002 % The RehearsalMark will be aligned with the left edge of the KeySignature
3003 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
3007 % The RehearsalMark will be aligned with the right edge of the KeySignature
3008 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
3014 The rehearsal mark can also be offset to the right or left of the left edge
3015 by an arbitrary amount. The units are staff-spaces:
3017 @lilypond[verbatim,quote,relative=1]
3018 % The RehearsalMark will be aligned with the left edge of the KeySignature
3019 % and then shifted right by 3.5 staff-spaces
3020 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
3021 \once \override Score.KeySignature #'break-align-anchor = #3.5
3025 % The RehearsalMark will be aligned with the left edge of the KeySignature
3026 % and then shifted left by 2 staff-spaces
3027 \once \override Score.KeySignature #'break-align-anchor = #-2
3035 @node Vertical grouping of grobs
3036 @subsection Vertical grouping of grobs
3038 @c FIXME Expand this section
3040 The VerticalAlignment and VerticalAxisGroup grobs work together.
3041 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3042 etc. VerticalAlignment then vertically aligns the different grobs
3043 grouped together by VerticalAxisGroup. There is usually only one
3044 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3048 @node Modifying stencils
3049 @subsection Modifying stencils
3051 All layout objects have a @code{stencil} property which is part of
3052 the @code{grob-interface}. By default, this property is usually
3053 set to a function specific to the object that is tailor-made to
3054 render the symbol which represents it in the output. For example,
3055 the standard setting for the @code{stencil} property of the
3056 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3058 The standard symbol for any object can be replaced by modifying the
3059 @code{stencil} property to reference a different, specially-written,
3060 procedure. This requires a high level of knowledge of the internal
3061 workings of LilyPond, but there is an easier way which can often
3062 produce adequate results.
3064 This is to set the @code{stencil} property to the procedure which
3065 prints text -- @code{ly:text-interface::print} -- and to add a
3066 @code{text} property to the object which is set to contain the
3067 markup text which produces the required symbol. Due to the
3068 flexibility of markup, much can be achieved -- see in particular
3069 @ref{Graphic notation inside markup}.
3071 The following example demonstrates this by changing the note head
3072 symbol to a cross within a circle.
3074 @lilypond[verbatim,quote]
3076 \once \override NoteHead #'stencil = #ly:text-interface::print
3077 \once \override NoteHead #'text = \markup {
3079 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3080 \musicglyph #"noteheads.s2cross"
3088 Any of the glyphs in the feta Font can be supplied to the
3089 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3091 @c TODO Add inserting eps files or ref to later
3093 @c TODO Add inserting Postscript or ref to later
3098 @ref{Graphic notation inside markup},
3099 @ref{Formatting text},
3100 @ref{Text markup commands},
3101 @ref{The Feta font}.
3104 @node Modifying shapes
3105 @subsection Modifying shapes
3108 * Modifying ties and slurs::
3111 @node Modifying ties and slurs
3112 @unnumberedsubsubsec Modifying ties and slurs
3114 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3115 curves. If the shape of the tie or slur which is calculated
3116 automatically is not optimum, the shape may be modified manually by
3117 explicitly specifying the four control points required to define
3118 a third-order Bézier curve.
3120 Third-order or cubic Bézier curves are defined by four control
3121 points. The first and fourth control points are precisely the
3122 starting and ending points of the curve. The intermediate two
3123 control points define the shape. Animations showing how the curve
3124 is drawn can be found on the web, but the following description
3125 may be helpful. The curve starts from the first control point
3126 heading directly towards the second, gradually bending over to
3127 head towards the third and continuing to bend over to head towards
3128 the fourth, arriving there travelling directly from the third
3129 control point. The curve is entirely contained in the
3130 quadrilateral defined by the four control points.
3132 Here is an example of a case where the tie is not optimum, and
3133 where @code{\tieDown} would not help.
3135 @lilypond[verbatim,quote,relative=1]
3139 { r4 <g c,> <g c,> <g c,> }
3143 One way of improving this tie is to manually modify its control
3146 The coordinates of the Bézier control points are specified in units
3147 of staff-spaces. The X@tie{}coordinate is relative to the reference
3148 point of the note to which the tie or slur is attached, and the
3149 Y@tie{}coordinate is relative to the staff center line. The
3150 coordinates are entered as a list of four pairs of decimal numbers
3151 (reals). One approach is to estimate the coordinates of the two
3152 end points, and then guess the two intermediate points. The optimum
3153 values are then found by trial and error.
3155 It is useful to remember that a symmetric curve requires symmetric
3156 control points, and that Bézier curves have the useful property that
3157 transformations of the curve such as translation, rotation and
3158 scaling can be achieved by applying the same transformation to the
3159 curve's control points.
3161 For the example above the following override gives a satisfactory
3164 @lilypond[verbatim,quote,relative=1]
3167 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3170 { r4 <g c,> <g c,> <g c,>4 }
3176 It is not possible to modify shapes of ties or slurs by changing
3177 the @code{control-points} property if there are more than one at
3178 the same musical moment, not even by using the @code{\tweak}