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::
67 @node Contexts explained
68 @subsection Contexts explained
71 @c TODO Rethink and rewrite
73 >> > > - list of contexts: my *danger unmaintainable*
74 >> > > alarm just went off. I'm
76 I knew it would... And leaving out some of them is perfectly fine
78 I do think that a list like this, with the main contexts and a
80 description of what they do (perhaps also with a note about what
82 behavior is associated with each of them, but this may be
84 should be there, and then we could simply list the remaining ones
86 further explanation and with links to the IR.
89 @c TODO Improve layout, order and consistency of wording -td
91 @c TODO Add introduction which explains contexts in generality -td
93 @c TODO Describe propagation of property values -td
95 Contexts are arranged heirarchically:
98 * Score - the master of all contexts::
99 * Top-level contexts - staff containers::
100 * Intermediate-level contexts - staves::
101 * Bottom-level contexts - voices::
104 @node Score - the master of all contexts
105 @unnumberedsubsubsec Score - the master of all contexts
107 This is the top level notation context. No other context can
108 contain a Score context. By default the Score context handles
109 the administration of time signatures and makes sure that items
110 such as clefs, time signatures, and key-signatures are aligned
113 A Score context is instantiated implicitly when a
114 @code{\score @{@dots{}@}} or @code{\layout @{@dots{}@}} block is
115 processed, or explicitly when a @code{\new Score} command is
118 @node Top-level contexts - staff containers
119 @unnumberedsubsubsec Top-level contexts - staff containers
121 @strong{@emph{StaffGroup}}
123 Groups staves while adding a bracket on the left side, grouping
124 the staves together. The bar lines of the contained staves are
125 connected vertically. StaffGroup only consists of a collection
126 of staves, with a bracket in front and spanning bar lines.
128 @strong{@emph{ChoirStaff}}
130 Identical to StaffGroup except that the bar lines of the contained
131 staves are not connected vertically.
133 @strong{@emph{GrandStaff}}
135 A group of staves, with a brace on the left side, grouping
136 the staves together. The bar lines of the contained staves are
137 connected vertically.
139 @strong{@emph{PianoStaff}}
141 @c TODO No longer correct? Check. -td
142 Just like GrandStaff but with a forced distance between the
143 staves, so cross staff beaming and slurring can be used.
146 @strong{@emph{InnerStaffGroup}}
150 @strong{@emph{InnerChoirStaff}}
156 @node Intermediate-level contexts - staves
157 @unnumberedsubsubsec Intermediate-level contexts - staves
159 @strong{@emph{Staff}}
161 Handles clefs, bar lines, keys, accidentals. It can contain
164 @strong{@emph{RhythmicStaff}}
166 Like Staff but for printing rhythms. Pitches are ignored;
167 the notes are printed on one line.
169 @strong{@emph{TabStaff}}
171 Context for generating tablature. By default lays the music
172 expression out as a guitar tablature, printed on six lines.
174 @strong{@emph{DrumStaff}}
176 Handles typesetting for percussion. Can contain DrumVoice
178 @strong{@emph{VaticanaStaff}}
180 Same as Staff, except that it is designed for typesetting
181 a piece in gregorian style.
183 @strong{@emph{MensuralStaff}}
185 Same as Staff, except that it is designed for typesetting
186 a piece in mensural style.
188 @node Bottom-level contexts - voices
189 @unnumberedsubsubsec Bottom-level contexts - voices
191 Voice-level contexts initialise certain properties and start
192 appropriate engravers. Being bottom-level contexts, they cannot
193 contain other contexts.
195 @strong{@emph{Voice}}
197 Corresponds to a voice on a staff. This context handles the
198 conversion of dynamic signs, stems, beams, super- and sub-scripts,
199 slurs, ties, and rests. You have to instantiate this explicitly
200 if you require multiple voices on the same staff.
202 @strong{@emph{VaticanaVoice}}
204 Same as Voice, except that it is designed for typesetting a piece
207 @strong{@emph{MensuralVoice}}
209 Same as Voice, with modifications for typesetting a piece in
212 @strong{@emph{Lyrics}}
214 Corresponds to a voice with lyrics. Handles the printing of a
215 single line of lyrics.
217 @strong{@emph{DrumVoice}}
219 The voice context used in a percussion staff.
221 @strong{@emph{FiguredBass}}
223 The context in which BassFigure objects are created from
224 input entered in @code{\figuremode} mode.
226 @strong{@emph{TabVoice}}
228 The voice context used within a TabStaff context. Usually left to
229 be created implicitly.
231 @strong{@emph{ChordNames}}
233 Typesets chord names.
238 Then the following, which I don't know what to do with:
240 * GregorianTranscriptionVoice
241 * GregorianTranscriptionStaff
244 Engraves fretboards from chords. Not easy... Not
246 There is now some documentation on FretBoards in the NR, under
247 instrument-specific notation -- cds.
251 * CueVoice Not documented
253 Hard coded entry point for LilyPond. Cannot be tuned.
255 Silently discards all musical information given to this
260 @node Creating contexts
261 @subsection Creating contexts
263 @c TODO \new Score and \score
264 @c TODO more complete descriptions rather than learning style
266 For scores with only one voice and one staff, contexts are
267 created automatically. For more complex scores, it is necessary to
268 create them by hand. There are three commands that do this.
273 The easiest command is @code{\new}, and it also the quickest to type.
274 It is prepended to a music expression, for example
278 @cindex Context, creating
281 \new @var{type} @var{music expression}
285 where @var{type} is a context name (like @code{Staff} or
286 @code{Voice}). This command creates a new context, and starts
287 interpreting the @var{music expression} with that.
289 A practical application of @code{\new} is a score with many
290 staves. Each part that should be on its own staff, is preceded with
293 @lilypond[quote,verbatim,relative=2,ragged-right,fragment]
300 The @code{\new} command may also give a name to the context,
303 \new @var{type} = @var{id} @var{music}
305 However, this user specified name is only used if there is no other
306 context already earlier with the same name.
312 Like @code{\new}, the @code{\context} command also directs a music
313 expression to a context object, but gives the context an explicit name. The
317 \context @var{type} = @var{id} @var{music}
320 This form will search for an existing context of type @var{type}
321 called @var{id}. If that context does not exist yet, a new
322 context with the specified name is created. This is useful if
323 the context is referred to later on. For example, when
324 setting lyrics the melody is in a named context
327 \context Voice = "@b{tenor}" @var{music}
331 so the texts can be properly aligned to its notes,
334 \new Lyrics \lyricsto "@b{tenor}" @var{lyrics}
339 Another possible use of named contexts is funneling two different
340 music expressions into one context. In the following example,
341 articulations and notes are entered separately,
345 arts = @{ s4-. s4-> @}
348 They are combined by sending both to the same @code{Voice} context,
352 \new Staff \context Voice = "A" \music
353 \context Voice = "A" \arts
356 @lilypond[quote,ragged-right]
360 \new Staff \context Voice = "A" \music
361 \context Voice = "A" \arts
365 With this mechanism, it is possible to define an Urtext (original
366 edition), with the option to put several distinct articulations on the
369 @cindex creating contexts
372 The third command for creating contexts is
374 \context @var{type} @var{music}
379 This is similar to @code{\context} with @code{= @var{id}}, but matches
380 any context of type @var{type}, regardless of its given name.
382 This variant is used with music expressions that can be interpreted at
383 several levels. For example, the @code{\applyOutput} command (see
384 @ref{Running a function on all layout objects}). Without an explicit
385 @code{\context}, it is usually applied to @code{Voice}
388 \applyOutput #'@var{context} #@var{function} % apply to Voice
391 To have it interpreted at the @code{Score} or @code{Staff} level use
395 \applyOutput #'Score #@var{function}
396 \applyOutput #'Staff #@var{function}
402 @node Modifying context plug-ins
403 @subsection Modifying context plug-ins
405 @c TODO Should this be Modifying engravers or Modifying contexts?
407 Notation contexts (like @code{Score} and @code{Staff}) not only
409 they also contain plug-ins called @q{engravers} that create notation
410 elements. For example, the @code{Voice} context contains a
411 @code{Note_head_engraver} and the @code{Staff} context contains a
412 @code{Key_signature_engraver}.
414 For a full a description of each plug-in, see
416 @rinternals{Engravers and Performers}.
419 Internals Reference @expansion{} Translation @expansion{} Engravers.
421 Every context described in
423 @rinternals{Contexts}
426 Internals Reference @expansion{} Translation @expansion{} Context.
428 lists the engravers used for that context.
431 It can be useful to shuffle around these plug-ins. This is done by
432 starting a new context with @code{\new} or @code{\context}, and
438 \new @var{context} \with @{
451 where the @dots{} should be the name of an engraver. Here is a simple
452 example which removes @code{Time_signature_engraver} and
453 @code{Clef_engraver} from a @code{Staff} context,
455 @lilypond[quote,relative=1,verbatim,fragment]
461 \remove "Time_signature_engraver"
462 \remove "Clef_engraver"
469 In the second staff there are no time signature or clef symbols. This
470 is a rather crude method of making objects disappear since it will affect
471 the entire staff. This method also influences the spacing, which may or
472 may not be desirable. More sophisticated methods of blanking objects
473 are shown in @rlearning{Visibility and color of objects}.
475 The next example shows a practical application. Bar lines and time
476 signatures are normally synchronized across the score. This is done
477 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
478 This plug-in keeps an administration of time signature, location
479 within the measure, etc. By moving these engraver from @code{Score} to
480 @code{Staff} context, we can have a score where each staff has its own
483 @cindex polymetric scores
484 @cindex Time signatures, multiple
486 @lilypond[quote,relative=1,ragged-right,verbatim,fragment]
488 \remove "Timing_translator"
489 \remove "Default_bar_line_engraver"
492 \consists "Timing_translator"
493 \consists "Default_bar_line_engraver"
499 \consists "Timing_translator"
500 \consists "Default_bar_line_engraver"
510 Usually the order in which the engravers are specified
511 does not matter, but in a few special cases the order
512 is important, for example where one engraver writes
513 a property and another reads it, or where one engraver
514 creates a grob and another must process it. The order in
515 which the engravers are specified is the order in which
516 they are called to carry out their processing.
518 The following orderings are important: the
519 @code{Bar_engraver} must normally be first, and
520 the @code{New_fingering_engraver} must come before
521 the @code{Script_column_engraver}. There may be others
522 with ordering dependencies.
524 @node Changing context default settings
525 @subsection Changing context default settings
527 The adjustments of the previous subsections (
528 @ref{The set command}, @ref{Modifying context plug-ins}, and
529 @ref{Overview of modifying properties}) can also be entered
530 separately from the music in the @code{\layout} block,
539 \override Stem #'thickness = #4.0
540 \remove "Time_signature_engraver"
545 The @code{\Staff} command brings in the existing definition of the
546 staff context so that it can be modified.
551 \override Stem #'thickness = #4.0
552 \remove "Time_signature_engraver"
556 affect all staves in the score. Other contexts can be modified
559 The @code{\set} keyword is optional within the @code{\layout} block, so
575 It is not possible to collect context changes in a variable and apply
576 them to a @code{\context} definition by referring to that variable.
578 The @code{\RemoveEmptyStaffContext} will overwrite your current
579 @code{\Staff} settings. If you wish to change the defaults for a
580 staff which uses @code{\RemoveEmptyStaffContext}, you must do so
581 after calling @code{\RemoveEmptyStaffContext}, ie
586 \RemoveEmptyStaffContext
588 \override Stem #'thickness = #4.0
593 @c TODO: add \with in here.
597 @node Defining new contexts
598 @subsection Defining new contexts
600 Specific contexts, like @code{Staff} and @code{Voice}, are made of
601 simple building blocks. It is possible to create new types of
602 contexts with different combinations of engraver plug-ins.
604 The next example shows how to build a different type of
605 @code{Voice} context from scratch. It will be similar to
606 @code{Voice}, but only prints centered slash note heads. It can be used
607 to indicate improvisation in jazz pieces,
609 @lilypond[quote,ragged-right]
612 \type "Engraver_group"
613 \consists "Note_heads_engraver"
614 \consists "Text_engraver"
615 \consists Pitch_squash_engraver
616 squashedPosition = #0
617 \override NoteHead #'style = #'slash
618 \override Stem #'transparent = ##t
622 \accepts "ImproVoice"
626 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
627 c4 c^"undress" c_"while playing :)" c }
633 These settings are defined within a @code{\context} block inside a
634 @code{\layout} block,
644 In the following discussion, the example input shown should go in place
645 of the @dots{} in the previous fragment.
647 First it is necessary to define a name for the new context:
653 Since it is similar to the @code{Voice}, we want commands that work
654 on (existing) @code{Voice}s to remain working. This is achieved by
655 giving the new context an alias @code{Voice},
661 The context will print notes and instructive texts, so we need to add
662 the engravers which provide this functionality,
665 \consists Note_heads_engraver
666 \consists Text_engraver
669 but we only need this on the center line,
672 \consists Pitch_squash_engraver
673 squashedPosition = #0
676 The @rinternals{Pitch_squash_engraver} modifies note heads (created
677 by @rinternals{Note_heads_engraver}) and sets their vertical
678 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
681 The notes look like a slash, and have no stem,
684 \override NoteHead #'style = #'slash
685 \override Stem #'transparent = ##t
688 All these plug-ins have to cooperate, and this is achieved with a
689 special plug-in, which must be marked with the keyword @code{\type}.
690 This should always be @code{Engraver_group}.
693 \type "Engraver_group"
701 \type "Engraver_group"
702 \consists "Note_heads_engraver"
703 \consists "Text_engraver"
704 \consists Pitch_squash_engraver
705 squashedPosition = #0
706 \override NoteHead #'style = #'slash
707 \override Stem #'transparent = ##t
713 Contexts form hierarchies. We want to hang the @code{ImproVoice}
714 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
715 modify the @code{Staff} definition with the @code{\accepts}
726 The opposite of @code{\accepts} is @code{\denies},
727 which is sometimes needed when reusing existing context definitions.
729 Putting both into a @code{\layout} block, like
739 \accepts "ImproVoice"
744 Then the output at the start of this subsection can be entered as
752 c c_"while playing :)"
759 @node Aligning contexts
760 @subsection Aligning contexts
762 New contexts may be aligned above or below existing contexts. This
763 could be useful in setting up a vocal staff (@rlearning{Vocal ensembles}) and
766 @c TODO Better example needed. Ref LM, and expand on it.
769 @findex alignAboveContext
770 @findex alignBelowContext
772 @lilypond[quote,ragged-right]
775 \relative c' \new Staff = "main" {
778 \new Staff \with {alignAboveContext=main} \ossia
786 @node Explaining the Internals Reference
787 @section Explaining the Internals Reference
791 * Navigating the program reference::
792 * Layout interfaces::
793 * Determining the grob property::
794 * Naming conventions::
797 @node Navigating the program reference
798 @subsection Navigating the program reference
800 @c TODO remove this (it's in the LM)
801 @c Replace with more factual directions
803 Suppose we want to move the fingering indication in the fragment
806 @lilypond[quote,fragment,relative=2,verbatim]
812 If you visit the documentation on fingering instructions (in
813 @ref{Fingering instructions}), you will notice:
818 Internals Reference: @rinternals{Fingering}.
823 @c outdated info; probably will delete.
825 This fragment points to two parts of the program reference: a page
826 on @code{FingeringEvent} and one on @code{Fingering}.
828 The page on @code{FingeringEvent} describes the properties of the music
829 expression for the input @code{-2}. The page contains many links
830 forward. For example, it says
833 Accepted by: @rinternals{Fingering_engraver},
837 That link brings us to the documentation for the Engraver, the
841 This engraver creates the following layout objects: @rinternals{Fingering}.
844 In other words, once the @code{FingeringEvent}s are interpreted, the
845 @code{Fingering_engraver} plug-in will process them.
849 @c I can't figure out what this is supposed to mean. -gp
851 The @code{Fingering_engraver} is also listed to create
852 @rinternals{Fingering} objects,
854 @c old info? it doesn't make any sense to me with our current docs.
856 second bit of information listed under @b{See also} in the Notation
861 The programmer's reference is available as an HTML document. It is
862 highly recommended that you read it in HTML form, either online or
863 by downloading the HTML documentation. This section will be much more
864 difficult to understand if you are using the
868 Follow the link to @rinternals{Fingering}. At the top of the
872 Fingering objects are created by: @rinternals{Fingering_engraver} and
873 @rinternals{New_fingering_engraver}.
876 By following related links inside the program reference, we can follow the
877 flow of information within the program:
881 @item @rinternals{Fingering}:
882 @rinternals{Fingering} objects are created by:
883 @rinternals{Fingering_engraver}
885 @item @rinternals{Fingering_engraver}:
886 Music types accepted: @rinternals{fingering-event}
888 @item @rinternals{fingering-event}:
889 Music event type @code{fingering-event} is in Music expressions named
890 @rinternals{FingeringEvent}
893 This path goes against the flow of information in the program: it
894 starts from the output, and ends at the input event. You could
895 also start at an input event, and read with the flow of
896 information, eventually ending up at the output object(s).
898 The program reference can also be browsed like a normal document. It
901 @rinternals{Music definitions},
904 @code{Music definitions}
906 on @rinternals{Translation}, and the @rinternals{Backend}. Every
907 chapter lists all the definitions used and all properties that may be
911 @node Layout interfaces
912 @subsection Layout interfaces
914 @cindex interface, layout
915 @cindex layout interface
918 The HTML page that we found in the previous section describes the
919 layout object called @rinternals{Fingering}. Such an object is a
920 symbol within the score. It has properties that store numbers (like
921 thicknesses and directions), but also pointers to related objects. A
922 layout object is also called a @emph{Grob}, which is short for Graphical
923 Object. For more details about Grobs, see @rinternals{grob-interface}.
925 The page for @code{Fingering} lists the definitions for the
926 @code{Fingering} object. For example, the page says
929 @code{padding} (dimension, in staff space):
935 which means that the number will be kept at a distance of at least 0.5
939 Each layout object may have several functions as a notational or
940 typographical element. For example, the Fingering object
941 has the following aspects
945 Its size is independent of the horizontal spacing, unlike slurs or beams.
948 It is a piece of text. Granted, it is usually a very short text.
951 That piece of text is typeset with a font, unlike slurs or beams.
954 Horizontally, the center of the symbol should be aligned to the
955 center of the note head.
958 Vertically, the symbol is placed next to the note and the staff.
961 The vertical position is also coordinated with other superscript
962 and subscript symbols.
965 Each of these aspects is captured in so-called @emph{interface}s,
966 which are listed on the @rinternals{Fingering} page at the bottom
969 This object supports the following interfaces:
970 @rinternals{item-interface},
971 @rinternals{self-alignment-interface},
972 @rinternals{side-position-interface}, @rinternals{text-interface},
973 @rinternals{text-script-interface}, @rinternals{font-interface},
974 @rinternals{finger-interface}, and @rinternals{grob-interface}.
977 Clicking any of the links will take you to the page of the respective
978 object interface. Each interface has a number of properties. Some of
979 them are not user-serviceable (@q{Internal properties}), but others
982 We have been talking of @emph{the} @code{Fingering} object, but actually it
983 does not amount to much. The initialization file (see
984 @rlearning{Other sources of information})
985 @file{scm/@/define@/-grobs@/.scm} shows the soul of the @q{object},
990 (avoid-slur . around)
992 (staff-padding . 0.5)
993 (self-alignment-X . 0)
994 (self-alignment-Y . 0)
995 (script-priority . 100)
996 (stencil . ,ly:text-interface::print)
997 (direction . ,ly:script-interface::calc-direction)
998 (font-encoding . fetaNumber)
999 (font-size . -5) ; don't overlap when next to heads.
1000 (meta . ((class . Item)
1001 (interfaces . (finger-interface
1003 text-script-interface
1005 side-position-interface
1006 self-alignment-interface
1007 item-interface))))))
1011 As you can see, the @code{Fingering} object is nothing more than a
1012 bunch of variable settings, and the webpage in the Internals Reference
1013 is directly generated from this definition.
1016 @node Determining the grob property
1017 @subsection Determining the grob property
1019 @c TODO remove this (it's in the LM)
1020 @c Replace with more factual directions
1022 Recall that we wanted to change the position of the @b{2} in
1024 @lilypond[quote,fragment,relative=2,verbatim]
1030 Since the @b{2} is vertically positioned next to its note, we have to
1031 meddle with the interface associated with this positioning. This is
1032 done using @code{side-position-interface}. The page for this interface
1036 @code{side-position-interface}
1038 Position a victim object (this one) next to other objects (the
1039 support). The property @code{direction} signifies where to put the
1040 victim object relative to the support (left or right, up or down?)
1045 Below this description, the variable @code{padding} is described as
1050 (dimension, in staff space)
1052 Add this much extra space between objects that are next to each other.
1056 By increasing the value of @code{padding}, we can move the
1057 fingering away from the note head. The following command inserts
1058 3 staff spaces of white
1059 between the note and the fingering:
1061 \once \override Voice.Fingering #'padding = #3
1064 Inserting this command before the Fingering object is created,
1065 i.e., before @code{c2}, yields the following result:
1067 @lilypond[quote,relative=2,fragment,verbatim]
1068 \once \override Voice.Fingering #'padding = #3
1075 In this case, the context for this tweak is @code{Voice}. This
1076 fact can also be deduced from the program reference, for the page for
1077 the @rinternals{Fingering_engraver} plug-in says
1080 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1084 @node Naming conventions
1085 @subsection Naming conventions
1087 Another thing that is needed, is an overview of the various naming
1090 scheme functions: lowercase-with-hyphens (incl. one-word
1092 scheme functions: ly:plus-scheme-style
1093 music events, music classes and music properties:
1095 Grob interfaces: scheme-style
1096 backend properties: scheme-style (but X and Y!)
1097 contexts (and MusicExpressions and grobs): Capitalized or
1099 context properties: lowercaseFollowedByCamelCase
1101 Capitalized_followed_by_lowercase_and_with_underscores
1103 Which of these are conventions and which are rules?
1104 Which are rules of the underlying language, and which are
1108 @node Modifying properties
1109 @section Modifying properties
1111 @c TODO change the menu and subsection node names to use
1112 @c backslash once the new macro to handle the refs
1113 @c is available. Need to find and change all refs at
1114 @c the same time. -td
1117 * Overview of modifying properties::
1119 * The override command::
1120 * The tweak command::
1121 * set versus override::
1125 @node Overview of modifying properties
1126 @subsection Overview of modifying properties
1128 Each context is responsible for creating certain types of graphical
1129 objects. The settings used for printing these objects are also stored by
1130 context. By changing these settings, the appearance of objects can be
1133 The syntax for this is
1136 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1139 Here @var{name} is the name of a graphical object, like
1140 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1141 variable of the formatting system (@q{grob property} or @q{layout
1142 property}). The latter is a symbol, so it must be quoted. The
1143 subsection @ref{Modifying properties}, explains what to fill in
1144 for @var{name}, @var{property}, and @var{value}. Here we only
1145 discuss the functionality of this command.
1150 \override Staff.Stem #'thickness = #4.0
1154 makes stems thicker (the default is 1.3, with staff line thickness as a
1155 unit). Since the command specifies @code{Staff} as context, it only
1156 applies to the current staff. Other staves will keep their normal
1157 appearance. Here we see the command in action:
1159 @lilypond[quote,verbatim,relative=2,fragment]
1161 \override Staff.Stem #'thickness = #4.0
1167 The @code{\override} command changes the definition of the @code{Stem}
1168 within the current @code{Staff}. After the command is interpreted
1169 all stems are thickened.
1171 Analogous to @code{\set}, the @var{context} argument may be left out,
1172 causing the default context @code{Voice} to be used. Adding
1173 @code{\once} applies the change during one timestep only.
1175 @lilypond[quote,fragment,verbatim,relative=2]
1177 \once \override Stem #'thickness = #4.0
1182 The @code{\override} must be done before the object is
1183 started. Therefore, when altering @emph{Spanner} objects such as slurs
1184 or beams, the @code{\override} command must be executed at the moment
1185 when the object is created. In this example,
1187 @lilypond[quote,fragment,verbatim,relative=2]
1188 \override Slur #'thickness = #3.0
1190 \override Beam #'thickness = #0.6
1195 the slur is fatter but the beam is not. This is because the command for
1196 @code{Beam} comes after the Beam is started, so it has no effect.
1198 Analogous to @code{\unset}, the @code{\revert} command for a context
1199 undoes an @code{\override} command; like with @code{\unset}, it only
1200 affects settings that were made in the same context. In other words, the
1201 @code{\revert} in the next example does not do anything.
1204 \override Voice.Stem #'thickness = #4.0
1205 \revert Staff.Stem #'thickness
1208 Some tweakable options are called @q{subproperties} and reside inside
1209 properties. To tweak those, use commands of the form
1211 @c leave this as a long long
1213 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1220 \override Stem #'details #'beamed-lengths = #'(4 4 3)
1226 Internals: @rinternals{OverrideProperty}, @rinternals{RevertProperty},
1227 @rinternals{PropertySet}, @rinternals{Backend}, and
1228 @rinternals{All layout objects}.
1233 The back-end is not very strict in type-checking object properties.
1234 Cyclic references in Scheme values for properties can cause hangs
1235 or crashes, or both.
1239 @node The set command
1240 @subsection The @code{\set} command
1244 @cindex changing properties
1246 Each context can have different @emph{properties}, variables contained
1247 in that context. They can be changed during the interpretation step.
1248 This is achieved by inserting the @code{\set} command in the music,
1251 \set @var{context}.@var{prop} = #@var{value}
1255 @lilypond[quote,verbatim,relative=2,fragment]
1257 \set Score.skipBars = ##t
1261 This command skips measures that have no notes. The result is that
1262 multi-rests are condensed. The value assigned is a Scheme object. In
1263 this case, it is @code{#t}, the boolean True value.
1265 If the @var{context} argument is left out, then the current bottom-most
1266 context (typically @code{ChordNames}, @code{Voice}, or
1267 @code{Lyrics}) is used. In this example,
1269 @lilypond[quote,verbatim,relative=2,fragment]
1271 \set autoBeaming = ##f
1276 the @var{context} argument to @code{\set} is left out, so automatic
1277 beaming is switched off in the current @rinternals{Voice}. Note that
1278 the bottom-most context does not always contain the property that you
1279 wish to change -- for example, attempting to set the @code{skipBars}
1280 property (of the bottom-most context, in this case @code{Voice}) will
1283 @lilypond[quote,verbatim,relative=2,fragment]
1289 Contexts are hierarchical, so if a bigger context was specified, for
1290 example @code{Staff}, then the change would also apply to all
1291 @code{Voice}s in the current stave. The change is applied
1292 @q{on-the-fly}, during the music, so that the setting only affects the
1293 second group of eighth notes.
1297 There is also an @code{\unset} command,
1299 \unset @var{context}.@var{prop}
1303 which removes the definition of @var{prop}. This command removes
1304 the definition only if it is set in @var{context}, so
1307 \set Staff.autoBeaming = ##f
1311 introduces a property setting at @code{Staff} level. The setting also
1312 applies to the current @code{Voice}. However,
1315 \unset Voice.autoBeaming
1319 does not have any effect. To cancel this setting, the @code{\unset}
1320 must be specified on the same level as the original @code{\set}. In
1321 other words, undoing the effect of @code{Staff.autoBeaming = ##f}
1324 \unset Staff.autoBeaming
1327 Like @code{\set}, the @var{context} argument does not have to be
1328 specified for a bottom context, so the two statements
1331 \set Voice.autoBeaming = ##t
1332 \set autoBeaming = ##t
1340 Settings that should only apply to a single time-step can be entered
1341 with @code{\once}, for example in
1343 @lilypond[quote,verbatim,relative=2,fragment]
1345 \once \set fontSize = #4.7
1350 the property @code{fontSize} is unset automatically after the second
1353 A full description of all available context properties is in the
1354 program reference, see
1356 @rinternals{Tunable context properties}.
1359 Translation @expansion{} Tunable context properties.
1364 @node The override command
1365 @subsection The @code{\override} command
1367 Commands which change output generally look like
1370 \override Voice.Stem #'thickness = #3.0
1374 To construct this tweak we must determine these bits of information:
1377 @item the context: here @code{Voice}.
1378 @item the layout object: here @code{Stem}.
1379 @item the layout property: here @code{thickness}.
1380 @item a sensible value: here @code{3.0}.
1383 Some tweakable options are called @q{subproperties} and reside inside
1384 properties. To tweak those, use commands in the form
1387 \override Stem #'details #'beamed-lengths = #'(4 4 3)
1390 @cindex internal documentation
1391 @cindex finding graphical objects
1392 @cindex graphical object descriptions
1395 @cindex internal documentation
1397 For many properties, regardless of the data type of the property, setting the
1398 property to false ( @code{##f} ) will result in turning it off, causing
1399 LilyPond to ignore that property entirely. This is particularly useful for
1400 turning off grob properties which may otherwise be causing problems.
1402 We demonstrate how to glean this information from the notation manual
1403 and the program reference.
1406 @node The tweak command
1407 @subsection The @code{\tweak} command
1412 In some cases, it is possible to take a short-cut for tuning
1413 graphical objects. For objects that are created directly from
1414 an item in the input file, you can use the @code{\tweak} command.
1417 @lilypond[relative=2,verbatim]
1422 \tweak #'duration-log #1
1425 -\tweak #'padding #8
1429 @cindex chord, modifying one note in
1431 But the main use of the @code{\tweak} command is to modify just
1432 one of a number of notation elements which start at the same musical
1433 moment, like the notes of a chord, or tuplet brackets which start
1436 For an introduction to the syntax and uses of the tweak command
1437 see @rlearning{Tweaking methods}.
1439 The @code{\tweak} command sets a property in the following object
1440 directly, without requiring the grob name or context to be
1441 specified. For this to work, it is necessary for the @code{\tweak}
1442 command to remain immediately adjacent to the object to which it is
1443 to apply after the input file has been converted to a music stream.
1444 This is often not the case, as many additional elements are inserted
1445 into the music stream implicitly. For example, when a note which is
1446 not part of a chord is processed, Lilypond implicitly inserts a
1447 @code{ChordEvent} event before the note, so separating the tweak
1448 from the note. However, if chord symbols are placed round the
1449 tweak and the note, the @code{\tweak} command comes after the
1450 @code{ChordEvent} in the music stream, so remaining adjacent to the
1451 note, and able to modify it.
1455 @lilypond[relative=2,verbatim,quote]
1456 <\tweak #'color #red c>4
1462 @lilypond[relative=2,verbatim,quote]
1463 \tweak #'color #red c4
1466 When several similar items are placed at the same musical moment,
1467 the @code{\override} command cannot be used to modify just one of
1468 them -- this is where the @code{\tweak} command must be used.
1469 Items which may appear more than once at the same musical moment
1470 include the following:
1472 @c TODO expand to include any further uses of \tweak
1474 @item note heads of notes inside a chord
1475 @item articulation signs on a single note
1476 @item ties between notes in a chord
1477 @item tuplet brackets starting at the same time
1480 @c TODO add examples of these
1483 and @code{\tweak} may be used to modify any single occurrence of
1486 Notably the @code{\tweak} command cannot be used to modify stems,
1487 beams or accidentals, since these are generated later by note heads,
1488 rather than by music elements in the input stream. Nor can a
1489 @code{\tweak} command be used to modify clefs or time signatures,
1490 since these become separated from any preceding @code{\tweak}
1491 command in the input stream by the automatic insertion of extra
1492 elements required to specify the context.
1494 But the @code{\tweak} command can be used as an alternative to
1495 the @code{\override} command to modify those notational elements
1496 that do not cause any additional implicit elements to be added
1497 before them in the music stream. For example, slurs may be
1498 modified in this way:
1500 @lilypond[verbatim,quote,relative=1]
1501 c-\tweak #'thickness #5 ( d e f)
1504 Also several @code{\tweak} commands may be placed before a
1505 notational element -- all affect it:
1507 @lilypond[verbatim,quote,relative=1]
1509 -\tweak #'style #'dashed-line
1510 -\tweak #'dash-fraction #0.2
1511 -\tweak #'thickness #3
1512 -\tweak #'color #red
1517 The music stream which is generated from a section of an input file,
1518 including any automatically inserted elements, may be examined,
1519 see @ref{Displaying music expressions}. This may be helpful in
1520 determining what may be modified by a @code{\tweak} command.
1525 @rlearning{Tweaking methods}.
1528 @ref{Displaying music expressions}.
1532 @cindex tweaks in a variable
1533 The @code{\tweak} command cannot be used inside a variable.
1535 @cindex tweaks in lyrics
1536 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1538 @cindex tweaking control points
1539 @cindex control points, tweaking
1541 The @code{\tweak} command cannot be used to modify the control
1542 points of just one of several ties in a chord, other than the first
1543 one encountered in the input file.
1545 @node set versus override
1546 @subsection @code{\set} vs. @code{\override}
1548 We have seen two methods of changing properties: @code{\set} and
1549 @code{\override}. There are actually two different kinds of
1552 Contexts can have properties, which are usually named in
1553 @code{studlyCaps}. They mostly control the translation from
1554 music to notation, eg. @code{localKeySignature} (for determining
1555 whether to print accidentals), @code{measurePosition} (for
1556 determining when to print a bar line). Context properties can
1557 change value over time while interpreting a piece of music;
1558 @code{measurePosition} is an obvious example of
1559 this. Context properties are modified with @code{\set}.
1561 There is a special type of context property: the element
1562 description. These properties are named in @code{StudlyCaps}
1563 (starting with capital letters). They contain the
1564 @q{default settings} for said graphical object as an
1565 association list. See @file{scm/@/define@/-grobs@/.scm}
1566 to see what kind of settings there are. Element descriptions
1567 may be modified with @code{\override}.
1569 @code{\override} is actually a shorthand;
1572 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1576 is more or less equivalent to
1578 @c leave this long line -gp
1580 \set @var{context}.@var{name} #'@var{property} = #(cons (cons '@var{property} @var{value}) <previous value of @var{context})
1583 The value of @code{context} (the alist) is used to initialize
1584 the properties of individual grobs. Grobs also have
1585 properties, named in Scheme style, with
1586 @code{dashed-words}. The values of grob properties change
1587 during the formatting process: formatting basically amounts
1588 to computing properties using callback functions.
1590 @code{fontSize} is a special property: it is equivalent to
1591 entering @code{\override ... #'font-size} for all pertinent
1592 objects. Since this is a common change, the special
1593 property (modified with @code{\set}) was created.
1596 @node Useful concepts and properties
1597 @section Useful concepts and properties
1602 * Direction and placement::
1603 * Distances and measurements::
1605 * Visibility of objects::
1607 * Rotating objects::
1611 @subsection Input modes
1613 The way in which the notation contained within an input file is
1614 interpreted is determined by the current input mode.
1618 This is activated with the @code{\chordmode} command, and causes
1619 input to be interpreted with the syntax of chord notation, see
1620 @ref{Chord notation}. Chords are rendered as notes on a staff.
1622 Chord mode is also activated with the @code{\chords} command.
1623 This also creates a new @code{ChordNames} context and
1624 causes the following input to be interpreted with the syntax of
1625 chord notation and rendered as chord names in the @code{ChordNames}
1626 context, see @ref{Printing chord names}.
1630 This is activated with the @code{\drummode} command, and causes
1631 input to be interpreted with the syntax of drum notation, see
1632 @ref{Basic percussion notation}.
1634 Drum mode is also activated with the @code{\drums} command.
1635 This also creates a new @code{DrumStaff} context and causes the
1636 following input to be interpreted with the syntax of drum notation
1637 and rendered as drum symbols on a drum staff, see @ref{Basic
1638 percussion notation}.
1640 @strong{Figure mode}
1642 This is activated with the @code{\figuremode} command, and causes
1643 input to be interpreted with the syntax of figured bass, see
1644 @ref{Entering figured bass}.
1646 Figure mode is also activated with the @code{\figures} command.
1647 This also creates a new @code{FiguredBass} context and causes the
1648 following input to be interpreted with the figured bass syntax
1649 and rendered as figured bass symbols in the @code{FiguredBass}
1650 context, see @ref{Introduction to figured bass}.
1652 @strong{Fret and tab modes}
1654 There are no special input modes for entering fret and tab symbols.
1656 To create tab diagrams, enter notes or chords in note mode and
1657 render them in a @code{TabStaff} context, see
1658 @ref{Default tablatures}.
1660 To create fret diagrams above a staff, you have two choices.
1661 You can either use the @code{FretBoards} context (see
1662 @ref{Automatic fret diagrams} or you can enter them as a markup
1663 above the notes using the @code{\fret-diagram} command (see
1664 @ref{Fret diagram markups}).
1666 @strong{Lyrics mode}
1668 This is activated with the @code{\lyricmode} command, and causes
1669 input to be interpreted as lyric syllables with optional durations
1670 and associated lyric modifiers, see @ref{Vocal music}.
1672 Lyric mode is also activated with the @code{\addlyrics} command.
1673 This also creates a new @code{Lyrics} context and an implicit
1674 @code{\lyricsto} command which associates the following lyrics
1675 with the preceding music.
1677 @strong{Markup mode}
1679 This is activated with the @code{\markup} command, and causes
1680 input to be interpreted with the syntax of markup, see
1681 @ref{Text markup commands}.
1683 @c silly work-around for texinfo broken-ness
1684 @c (@strong{Note...} causes a spurious cross-reference in Info)
1687 This is the default mode or it may be activated with the
1688 @code{\notemode} command. Input is interpreted as pitches,
1689 durations, markup, etc and typeset as musical notation on a staff.
1691 It is not normally necessary to specify note mode explicitly, but
1692 it may be useful to do so in certain situations, for example if you
1693 are in lyric mode, chord mode or any other mode and want to insert
1694 something that only can be done with note mode syntax.
1696 For example, to indicate dynamic markings for the verses of a
1697 choral pieces it is necessary to enter note mode to interpret
1700 @lilypond[verbatim,relative=2,quote]
1703 \notemode{\set stanza = \markup{ \dynamic f 1. } }
1707 \notemode{\set stanza = \markup{ \dynamic p 2. } }
1714 @node Direction and placement
1715 @subsection Direction and placement
1717 In typesetting music the direction and placement of many items is
1718 a matter of choice. For example, the stems of notes can
1719 be directed up or down; lyrics, dynamics, and other expressive
1720 marks may be placed above or below the staff; text may be aligned
1721 left, right or center; etc. Most of these choices may be left to
1722 be determined automatically by LilyPond, but in some cases it may
1723 be desirable to force a particular direction or placement.
1725 @strong{Default actions}
1727 By default some directions are always up or always down (e.g.
1728 dynamics or fermata), while other things can alternate between
1729 up or down based on the stem direction (like slurs or accents).
1731 @c TODO Add table showing these
1733 @strong{Context layout}
1735 Contexts are positioned in a system from top to bottom in the
1736 order in which they are encountered. Note, however, that a
1737 context will be created implicitly if a command is encountered
1738 when there is no suitable context available to contain it.
1740 @c TODO Add example ?
1742 The default order in which contexts are laid out can be changed,
1743 see @ref{Aligning contexts}
1745 @strong{Articulation direction indicators}
1747 When adding articulations to notes the direction indicator,
1748 @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down}) or
1749 @code{-} (meaning @qq{use default direction}), can usually be
1750 omitted, in which case @code{-} is assumed. But a direction
1751 indicator is @strong{always} required before
1754 @item @code{\tweak} commands
1755 @item @code{\markup} commands
1756 @item @code{\tag} commands
1757 @item string markups, e.g. -"string"
1758 @item fingering instructions, e.g. @code{-1}
1759 @item articulation shortcuts, e.g. @code{-.}, @code{->}, @code{--}
1762 @strong{The direction property}
1764 The position or direction of many layout objects is controlled
1765 by the @code{direction} property.
1767 The value of the @code{direction} property may be
1768 set to @code{1}, meaning @qq{up} or @qq{above}, or to @code{-1},
1769 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
1770 @code{DOWN} may be used instead of @code{1} and @code{-1}
1771 respectively. The default direction may be specified by setting
1772 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
1773 in many cases predefined commands
1774 exist to specify the direction. These are all of the form
1777 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
1780 where @code{xxxNeutral} means @qq{use the default direction}.
1781 See @rlearning{Within-staff objects}.
1783 In a few cases, arpeggio being the only common example, the value
1784 of the @code{direction} property specifies whether the object
1785 is to be placed to the right or left of the parent object. In
1786 this case @code{-1} or @code{LEFT} means @qq{to the left} and
1787 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
1788 or @code{CENTER} means @qq{use the default} direction, as before.
1791 These all have side-axis set to #X
1792 AmbitusAccidental - direction has no effect
1794 StanzaNumber - not tried
1795 TrillPitchAccidental - not tried
1796 TrillPitchGroup - not tried
1801 @node Distances and measurements
1802 @subsection Distances and measurements
1804 @cindex distances, absolute
1805 @cindex distances, scaled
1812 Distances in LilyPond are of two types: absolute and scaled.
1814 Absolute distances are used for specifying margins, indents, and
1815 other page layout details, and are by default specified in
1816 millimeters. Distances may be specified in other units by
1817 following the quantity by @code{\mm}, @code{\cm},
1818 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27
1819 of an inch). Page layout distances can also be specified in
1820 scalable units (see the following paragraph) by appending
1821 @code{\staff-space} to the quantity.
1822 Page layout is described in detail in @ref{Page formatting}.
1824 Scaled distances are always specified in units of the staff-space
1825 or, rarely, the half staff-space. The staff-space is the distance
1826 between two adjacent staff lines. The default value can be changed
1827 globally by setting the global staff size, or it can be overridden
1828 locally by changing the @code{staff-space} property of
1829 @code{StaffSymbol}. Scaled distances automatically scale with any
1830 change to the either the global staff size or the
1831 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
1832 automatically only with changes to the global staff size.
1833 The global staff size thus enables the overall size of a rendered
1834 score to be easily varied. For the methods of setting the global
1835 staff size see @ref{Setting the staff size}.
1839 If just a section of a score needs to be rendered to a different
1840 scale, for example an ossia section or a footnote, the global staff
1841 size cannot simply be changed as this would affect the entire score.
1842 In such cases the change in size is made by overriding both the
1843 @code{staff-space} property of @code{StaffSymbol} and the size of
1844 the fonts. A Scheme function, @code{magstep}, is available to
1845 convert from a font size change to the equivalent change in
1846 @code{staff-space}. For an explanation and an example of its use,
1847 see @rlearning{Length and thickness of objects}.
1852 @rlearning{Length and thickness of objects}.
1855 @ref{Page formatting},
1856 @ref{Setting the staff size}.
1860 @subsection Spanners
1862 Many objects of musical notation extend over several notes or even
1863 several bars. Examples are slurs, beams, tuplet brackets, volta
1864 repeat brackets, crescendi, trills, and glissandi. Such objects
1865 are collectively called @qq{spanners}, and have special properties to control
1866 their appearance and behaviour. Some of these properties are common
1867 to all spanners; others are restricted to a sub-set of the spanners.
1869 All spanners support the @code{spanner-interface}. A few, esentially
1870 those that draw a straight line between the two objects, support in
1871 addition the @code{line-spanner-interface}.
1873 @unnumberedsubsubsec Using the @code{spanner-interface}
1875 This interface provides two properties that apply to several spanners.
1877 @strong{@i{The @code{minimum-length} property}}
1879 The minimum length of the spanner is specified by the
1880 @code{minimum-length} property. Increasing this usually has the
1881 necessary effect of increasing the spacing of the notes between the
1882 two end points. However, this override has no effect on
1883 many spanners, as their length is determined by other considerations.
1884 A few examples where it is effective are shown below.
1894 Works as long as callback is made:
1898 Works not at all for:
1907 @lilypond[verbatim,quote,relative=2]
1910 % increase the length of the tie
1911 -\tweak #'minimum-length #5
1915 @lilypond[verbatim,quote,relative=2]
1917 \compressFullBarRests
1919 % increase the length of the rest bar
1920 \once \override MultiMeasureRest #'minimum-length = #20
1925 @lilypond[verbatim,quote,relative=2]
1927 % increase the length of the hairpin
1928 \override Hairpin #'minimum-length = #20
1932 This override can also be used to increase the length of slurs and
1935 @lilypond[verbatim,quote,relative=2]
1938 -\tweak #'minimum-length #5
1943 -\tweak #'minimum-length #5
1947 For some layout objects, the @code{minimum-length} property becomes
1948 effective only if the @code{set-spacing-rods} procedure is called
1949 explicitly. To do this, the @code{springs-and-rods} property should
1950 be set to @code{ly:spanner::set-spacing-rods}. For example,
1951 the minimum length of a glissando has no effect unless the
1952 @code{springs-and-rods} property is set:
1954 @lilypond[verbatim,quote,relative=1]
1958 % not effective alone
1959 \once \override Glissando #'minimum-length = #20
1962 % effective only when both overrides are present
1963 \once \override Glissando #'minimum-length = #20
1964 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
1968 The same is true of the @code{Beam} object:
1970 @lilypond[verbatim,quote,relative=1]
1971 % not effective alone
1972 \once \override Beam #'minimum-length = #20
1975 % effective only when both overrides are present
1976 \once \override Beam #'minimum-length = #20
1977 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
1981 @strong{@i{The @code{to-barline} property}}
1983 The second useful property of the @code{spanner-interface} is
1984 @code{to-barline}. By default this is true, causing hairpins and
1985 other spanners which are terminated on the first note of a measure to
1986 end instead on the immediately preceding bar line. If set to false,
1987 the spanner will extend beyond the bar line and end on the note
1990 @lilypond[verbatim,quote,relative=2]
1991 a \< a a a a \! a a a \break
1992 \override Hairpin #'to-barline = ##f
1993 a \< a a a a \! a a a
1996 This property is not effective for all spanners. For example,
1997 seting it to @code{#t} has no effect on slurs or phrasing slurs
1998 or on other spanners for which terminating on the bar line would
2001 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2003 Objects which support the @code{line-spanner-interface} include
2006 @item @code{DynamicTextSpanner}
2007 @item @code{Glissando}
2008 @item @code{TextSpanner}
2009 @item @code{TrillSpanner}
2010 @item @code{VoiceFollower}
2013 The routine responsible for drawing the stencils for these spanners is
2014 @code{ly:line-interface::print}. This routine determines the
2015 exact location of the two end points and draws a line
2016 between them, in the style requested. The locations of the two
2017 end points of the spanner are computed on-the-fly, but it is
2018 possible to override their Y-coordinates. The
2019 properties which need to be specified are nested
2020 two levels down within the property hierarchy, but the syntax of
2021 the @code{\override} command is quite simple:
2023 @lilypond[relative=2,quote,verbatim]
2025 \once \override Glissando #'bound-details #'left #'Y = #3
2026 \once \override Glissando #'bound-details #'right #'Y = #-2
2030 The units for the @code{Y} property are @code{staff-space}s,
2031 with the center line of the staff being the zero point.
2032 For the glissando, this is the value for @code{Y} at the
2033 X-coordinate corresponding to the center point of each note head,
2034 if the line is imagined to be extended to there.
2036 If @code{Y} is not set, the value is computed from the vertical
2037 position of the corresponding attachment point of the spanner.
2039 In case of a line break, the values for the end points are
2040 specified by the @code{left-broken} and @code{right-broken}
2041 sub-lists of @code{bound-details}. For example:
2043 @lilypond[relative=2,ragged-right,verbatim,fragment]
2044 \override Glissando #'breakable = ##t
2045 \override Glissando #'bound-details #'right-broken #'Y = #-3
2046 c1 \glissando \break
2051 A number of further properties of the @code{left} and
2052 @code{right} sub-lists of the @code{bound-details} property
2053 may be modified in the same way as @code{Y}:
2057 This sets the Y-coordinate of the end point, in @code{staff-space}s
2058 offset from the staff center line. By default, it is the center of
2059 the bound object, so a glissando points to the vertical center of
2062 For horizontal spanners, such as text spanners and trill spanners,
2063 it is hardcoded to 0.
2066 This determines where the line starts and ends in the X-direction,
2067 relative to the bound object. So, a value of @code{-1} (or
2068 @code{LEFT}) makes the line start/end at the left side of the note
2069 head it is attached to.
2072 This is the absolute X-coordinate of the end point. It is usually
2073 computed on the fly, and overriding it has little useful effect.
2076 Line spanners may have symbols at the beginning or end, which is
2077 contained in this sub-property. This is for internal use; it is
2078 recommended that @code{text} be used instead.
2081 This is a markup that is evaluated to yield the stencil. It is used
2082 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2084 @lilypond[quote,ragged-right,fragment,relative=2,verbatim]
2085 \override TextSpanner #'bound-details #'left #'text
2086 = \markup { \small \bold Slower }
2087 c2\startTextSpan b c a\stopTextSpan
2090 @item stencil-align-dir-y
2091 @item stencil-offset
2092 Without setting one of these, the stencil is simply put at the
2093 end-point, centered on the line, as defined by the @code{X} and
2094 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2095 or @code{stencil-offset} will move the symbol at the edge vertically
2096 relative to the end point of the line:
2098 @lilypond[relative=1,fragment,verbatim]
2099 \override TextSpanner #'bound-details
2100 #'left #'stencil-align-dir-y = #-2
2101 \override TextSpanner #'bound-details
2102 #'right #'stencil-align-dir-y = #UP
2104 \override TextSpanner #'bound-details
2105 #'left #'text = #"ggg"
2106 \override TextSpanner #'bound-details
2107 #'right #'text = #"hhh"
2108 c4^\startTextSpan c c c \stopTextSpan
2111 Note that negative values move the text @emph{up}, contrary to the
2112 effect that might be expected, as a value of @code{-1} or
2113 @code{DOWN} means align the @emph{bottom} edge of the text with
2114 the spanner line. A value of @code{1} or @code{UP} aligns
2115 the top edge of the text with the spanner line.
2118 Setting this sub-property to @code{#t} produces an arrowhead at the
2122 This sub-property controls the space between the specified
2123 end point of the line and the actual end. Without padding, a
2124 glissando would start and end in the center of each note head.
2128 The music function @code{\endSpanners} terminates the spanner
2129 which starts on the immediately following note prematurely. It
2130 is terminated after exactly one note, or at the following bar line
2131 if @code{to-barline} is true and a bar line occurs before the next
2134 @lilypond[verbatim,quote,ragged-right,relative=2,fragment]
2136 c2 \startTextSpan c2 c2
2141 When using @code{\endSpanners} it is not necessary to close
2142 \startTextSpan with \stopTextSpan, nor is it necessary to close
2143 hairpins with @code{\!}.
2149 Internals Reference: @rinternals{TextSpanner},
2150 @rinternals{Glissando}, @rinternals{VoiceFollower},
2151 @rinternals{TrillSpanner},
2152 @rinternals{line-spanner-interface}.
2155 @node Visibility of objects
2156 @subsection Visibility of objects
2158 @cindex objects, visibility of
2159 @cindex grobs, visibility of
2160 @cindex visibility of objects
2162 There are four main ways in which the visibility of layout objects
2163 can be controlled: their stencil can be removed, they can be made
2164 transparent, they can be colored white, or their
2165 @code{break-visibility} property can be overridden. The first
2166 three apply to all layout objects; the last to just a few -- the
2167 @emph{breakable} objects. The Learning Manual introduces these
2168 four techniques, see @rlearning{Visibility and color of objects}.
2170 There are also a few other techniques which are specific to
2171 certain layout objects. These are covered under Special
2175 * Removing the stencil::
2176 * Making objects transparent::
2177 * Painting objects white::
2178 * Using break-visibility::
2179 * Special considerations::
2183 @node Removing the stencil
2184 @unnumberedsubsubsec Removing the stencil
2186 @cindex stencil, removing
2188 Every layout object has a stencil property. By default this is set
2189 to the specific function which draws that object. If this property
2190 is overridden to @code{#f} no function will be called and the object
2191 will not be drawn. The default action can be recovered with
2194 @lilypond[quote,verbatim,relative=1]
2196 \override Score.BarLine #'stencil = ##f
2198 \revert Score.BarLine #'stencil
2202 @node Making objects transparent
2203 @unnumberedsubsubsec Making objects transparent
2205 @cindex transparent, making objects
2207 Every layout object has a transparent property which by default is
2208 set to @code{#f}. If set to @code{#t} the object still occupies
2209 space but is made invisible.
2211 @lilypond[quote,verbatim,relative=2]
2213 \once \override NoteHead #'transparent = ##t
2217 @node Painting objects white
2218 @unnumberedsubsubsec Painting objects white
2220 @cindex objects, coloring
2221 @cindex coloring objects
2223 @cindex printing order
2224 @cindex overwriting objects
2225 @cindex objects, overwriting
2226 @cindex grobs, overwriting
2228 Every layout object has a color property which by default is set
2229 to @code{black}. If this is overridden to @code{white} the object
2230 will be indistinguishable from the white background. However,
2231 if the object crosses other objects the color of the crossing
2232 points will be determined by the order in which they are drawn,
2233 and this may leave a ghostly image of the white object, as shown
2236 @lilypond[quote,verbatim,relative=2]
2237 \override Staff.Clef #'color = #white
2241 This may be avoided by changing the order of printing the objects.
2242 All layout objects have a @code{layer} property which should be set
2243 to an integer. Objects with the lowest value of @code{layer} are
2244 drawn first, then objects with progressively higher values are drawn,
2245 so objects with higher values overwrite objects with lower values.
2246 By default most objects are assigned a @code{layer} value of
2247 @code{1}, although a few objects, including @code{StaffSymbol} and
2248 @code{BarLine}, are assigned a value of @code{0}. The order of
2249 printing objects with the same value of @code{layer} is indeterminate.
2251 In the example above the white clef, with a default @code{layer}
2252 value of @code{1}, is drawn after the staff lines (default
2253 @code{layer} value @code{0}), so overwriting them. To change this,
2254 the @code{Clef} object must be given in a lower value of
2255 @code{layer}, say @code{-1}, so that it is drawn earlier:
2257 @lilypond[quote,verbatim,relative=2]
2258 \override Staff.Clef #'color = #white
2259 \override Staff.Clef #'layer = #-1
2263 @node Using break-visibility
2264 @unnumberedsubsubsec Using break-visibility
2266 @c TODO Add making other objects breakable
2268 @cindex break-visibility
2270 Most layout objects are printed only once, but some like
2271 bar lines, clefs, time signatures and key signatures, may need
2272 to be printed twice when a line break occurs -- once at the end
2273 of the line and again at the start of the next line. Such
2274 objects are called @emph{breakable}, and have a property, the
2275 @code{break-visibility} property to control their visibility
2276 at the three positions in which they may appear -- at the
2277 start of a line, within a line if they are changed, and at the
2278 end of a line if a change takes place there.
2280 For example, the time signature
2281 by default will be printed at the start of the first line, but
2282 nowhere else unless it changes, when it will be printed at the
2283 point at which the change occurs. If this change occurs at the
2284 end of a line the new time signature will be printed at the start
2285 of the next line and a cautionary time signature will be printed
2286 at the end of the previous line as well.
2288 This behaviour is controlled by the @code{break-visibility}
2289 property, which is explained in
2290 @c Leave this ref on a newline - formats incorrectly otherwise -td
2291 @rlearning{Visibility and color of objects}. This property takes
2292 a vector of three booleans which, in order, determine whether the
2293 object is printed at the end of, within the body of, or at the
2294 beginning of a line. Or to be more precise, before a line break,
2295 where there is no line break, or after a line break.
2297 Alternatively, seven of the eight combinations may be specified
2298 by pre-defined functions, defined in @file{scm/output-lib.scm},
2299 where the last three columns indicate whether the layout objects
2300 will be visible in the positions shown at the head of the columns:
2302 @multitable @columnfractions .40 .15 .1 .1 .1
2303 @c TODO check these more carefully
2304 @headitem Function @tab Vector @tab Before @tab At no @tab After
2305 @headitem form @tab form @tab break @tab break @tab break
2307 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @ @ @tab no @tab no @tab no
2308 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2309 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2310 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2311 @c The center-visible function is not defined
2312 @c @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2313 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2314 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2315 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2318 The @code{center-visible} function is not pre-defined.
2320 The default settings of @code{break-visibility} depend on the
2321 layout object. The following table shows all the layout objects
2322 of interest which are affected by @code{break-visibility} and the
2323 default setting of this property:
2325 @multitable @columnfractions .3 .3 .4
2327 @headitem Layout object @tab Usual context @tab Default setting
2329 @c omit Ambitus as it appears not to be affected by break-visibility -td
2330 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2331 @item @code{BarLine} @tab @code{Score} @tab calculated
2332 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2333 @c omit the following item until it can be explained -td
2334 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2335 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2336 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2337 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2338 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2339 @c omit KeyCancellation until it can be explained -td
2340 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2341 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2342 @c omit LeftEdge until it can be explained -td
2343 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2344 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2345 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2346 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2350 The example below shows the use of the vector form to control the
2351 visibility of barlines:
2353 @lilypond[quote,verbatim,relative=1,ragged-right]
2356 % Remove bar line at the end of the current line
2357 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2363 Although all three components of the vector used to override
2364 @code{break-visibility} must be present, not all of them are
2365 effective with every layout object, and some combinations may
2366 even give errors. The following limitations apply:
2369 @item Bar lines cannot be printed at start of line.
2370 @item A bar number cannot be printed at the start of the first
2371 line unless it is set to be different from 1.
2372 @item Clef -- see below
2373 @item Double percent repeats are either all printed or all
2374 suppressed. Use begin-of line-invisible to print and
2375 all-invisible to suppress.
2376 @item Key signature -- see below
2377 @item OctavateEight -- see below
2380 @node Special considerations
2381 @unnumberedsubsubsec Special considerations
2383 @strong{@emph{Visibility following explicit changes}}
2385 @cindex key signature, visibility following explicit change
2386 @cindex explicitKeySignatureVisibility
2387 @cindex clef, visibility following explicit change
2388 @cindex explicitClefVisibility
2390 The @code{break-visibility} property controls the visibility of
2391 key signatures and changes of clef only at the start of lines,
2392 i.e. after a break. It has no effect on the visibility of the
2393 key signature or clef following an explicit key change or an
2394 explicit clef change within or at the end of a line. In the
2395 following example the key signature following the explicit change
2396 to B-flat major is still visible, even though @code{all-invisible}
2399 @lilypond[quote,verbatim,relative=1,ragged-right]
2402 % Try to remove all key signatures
2403 \override Staff.KeySignature #'break-visibility = #all-invisible
2411 The visibility of such explicit key signature and clef changes is
2412 controlled by the @code{explicitKeySignatureVisibility} and
2413 @code{explicitClefVisibility} properties. These are the equivalent
2414 of the @code{break-visibility} property and both take a vector of
2415 three booleans or the predefined functions listed above, exactly like
2416 @code{break-visibility}. Both are properties of the Staff context,
2417 not the layout objects themselves, and so they are set using the
2418 @code{\set} command. Both are set by default to @code{all-visible}.
2419 These properties control only the visibility of key signatures and
2420 clefs resulting from explicit changes and do not affect key
2421 signatures and clefs at the beginning of lines;
2422 @code{break-visibility} must still be overridden in the appropriate
2423 object to remove these.
2425 @lilypond[quote,verbatim,relative=1,ragged-right]
2428 \set Staff.explicitKeySignatureVisibility = #all-invisible
2429 \override Staff.KeySignature #'break-visibility = #all-invisible
2436 @strong{@emph{Visibility of cautionary accidentals}}
2438 To remove the cautionary accidentals printed at an explicit key
2439 change, set the Staff context property @code{printKeyCancellation}
2442 @lilypond[quote,verbatim,relative=1,ragged-right]
2445 \set Staff.explicitKeySignatureVisibility = #all-invisible
2446 \set Staff.printKeyCancellation = ##f
2447 \override Staff.KeySignature #'break-visibility = #all-invisible
2454 With these overrides only the accidentals before the notes remain
2455 to indicate the change of key.
2457 @c TODO Add visibility of cautionary accidentals before notes
2459 @strong{@emph{Automatic bars}}
2461 @cindex automaticBars
2462 @cindex bar lines, suppressing
2464 As a special case, the printing of bar lines can also be turned off
2465 by setting the @code{automaticBars} property in the Score context.
2466 If set to @code{#f}, bar lines will not be printed automatically;
2467 they must be explicitly created with a @code{\bar} command. Unlike
2468 the @code{\cadenzaOn} predefined command, measures are still counted.
2469 Bar generation will resume according to that count if this property
2470 is later set to @code{#t}. When set to @code{#f}, line breaks can
2471 occur only at explicit @code{\bar} commands.
2475 @strong{@emph{Octavated clefs}}
2477 @cindex octavated clefs, visibility of
2478 @cindex visibility of octavated clefs
2479 @cindex clefs, visibility of octavation
2481 The small octavation symbol on octavated clefs is produced by the
2482 @code{OctavateEight} layout object. Its visibility is controlled
2483 independently from that of the @code{Clef} object, so it is
2484 necessary to apply any required @code{break-visibility} overrides
2485 to both the @code{Clef} and the @code{OctavateEight} layout objects
2486 to fully suppress such clef symbols at the start of each line.
2488 For explicit clef changes, the @code{explicitClefVisibility}
2489 property controls both the clef symbol and any octavation symbol
2495 @rlearning{Visibility and color of objects}
2499 @subsection Line styles
2501 Some performance indications, e.g., @i{rallentando} and
2502 @i{accelerando} and @i{trills} are written as text and are
2503 extended over many measures with lines, sometimes dotted or wavy.
2505 These all use the same routines as the glissando for drawing the
2506 texts and the lines, and tuning their behavior is therefore also
2507 done in the same way. It is done with a spanner, and the routine
2508 responsible for drawing the spanners is
2509 @code{ly:line-interface::print}. This routine determines the
2510 exact location of the two @i{span points} and draws a line
2511 between them, in the style requested.
2513 Here is an example showing the different line styles available,
2514 and how to tune them.
2516 @lilypond[relative=2,ragged-right,verbatim,fragment]
2518 \once \override Glissando #'style = #'dashed-line
2520 \override Glissando #'style = #'dotted-line
2522 \override Glissando #'style = #'zigzag
2524 \override Glissando #'style = #'trill
2528 The locations of the end-points of the spanner are computed
2529 on-the-fly for every graphic object, but it is possible to
2533 @lilypond[relative=2,ragged-right,verbatim,fragment]
2535 \once \override Glissando #'bound-details #'right #'Y = #-2
2539 The value for @code{Y} is set to @code{-2} for the right end
2540 point. The left side may be similarly adjusted by specifying
2541 @code{left} instead of @code{right}.
2543 If @code{Y} is not set, the value is computed from the vertical
2544 position of the left and right attachment points of the spanner.
2546 Other adjustments of spanners are possible, for details, see
2549 @node Rotating objects
2550 @subsection Rotating objects
2552 Both layout objects and elements of markup text can be rotated by
2553 any angle about any point, but the method of doing so differs.
2556 * Rotating layout objects::
2560 @node Rotating layout objects
2561 @unnumberedsubsubsec Rotating layout objects
2563 @cindex rotating objects
2564 @cindex objects, rotating
2566 All layout objects which support the @code{grob-interface} can be
2567 rotated by setting their @code{rotation} property. This takes a
2568 list of three items: the angle of rotation counter-clockwise,
2569 and the x and y coordinates of the point relative to the object's
2570 reference point about which the rotation is to be performed. The
2571 angle of rotation is specified in degrees and the coordinates in
2574 The angle of rotation and the coordinates of the rotation point must
2575 be determined by trial and error.
2577 @cindex hairpins, angled
2578 @cindex angled hairpins
2580 There are only a few situations where the rotation of layout
2581 objects is useful; the following example shows one situation where
2584 @lilypond[quote,verbatim,relative=1]
2586 \override Hairpin #'rotation = #'(20 -1 0)
2590 @node Rotating markup
2591 @unnumberedsubsubsec Rotating markup
2593 All markup text can be rotated to lie at any angle by prefixing it
2594 with the @code{\rotate} command. The command takes two arguments:
2595 the angle of rotation in degrees counter-clockwise and the text to
2596 be rotated. The extents of the text are not rotated: they take
2597 their values from the extremes of the x and y coordinates of the
2598 rotated text. In the following example the
2599 @code{outside-staff-priority} property for text is set to @code{#f}
2600 to disable the automatic collision avoidance, which would push some
2601 of the text too high.
2603 @lilypond[quote,verbatim,relative=1]
2604 \override TextScript #'outside-staff-priority = ##f
2605 g4^\markup { \rotate #30 "a G" }
2606 b^\markup { \rotate #30 "a B" }
2607 des^\markup { \rotate #30 "a D-Flat" }
2608 fis^\markup { \rotate #30 "an F-Sharp" }
2611 @node Advanced tweaks
2612 @section Advanced tweaks
2615 * Aligning objects::
2616 * Vertical grouping of grobs::
2617 * Modifying stencils::
2618 * Modifying shapes::
2621 @node Aligning objects
2622 @subsection Aligning objects
2624 Graphical objects which support the @code{self-alignment-interface} and/or
2625 the @code{side-position-interface} can be
2626 aligned to a previously placed object in a variety of ways. For a list of these objects, see
2627 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
2629 All graphical objects have a reference point, a horizontal extent and a
2630 vertical extent. The horizontal extent is a pair of numbers
2631 giving the displacements from the reference point of the left and
2632 right edges, displacements to the left being negative. The
2633 vertical extent is a pair of numbers giving the displacement from
2634 the reference point to the bottom and top edges, displacements down
2637 An object's position on a staff is given by the values of the
2638 @code{X-offset} and @code{Y-offset} properties. The value of
2639 @code{X-offset} gives the displacement from the x coordinate of
2640 the reference point of the parent object, and the value of
2641 @code{Y-offset} gives the displacement from the center line of the
2642 staff. The values of @code{X-offset} and
2643 @code{Y-offset} may be set directly or may be set to be calculated
2644 by procedures in order to achieve alignment with the parent object
2647 @warning{Many objects have special positioning considerations which
2648 cause any setting of @code{X-offset} or @code{Y-offset} to be
2649 ignored or modified, even though the object supports the
2650 @code{self-alignment-interface}.}
2652 For example, an accidental can be repositioned
2653 vertically by setting @code{Y-offset} but any changes to
2654 @code{X-offset} have no effect.
2656 Rehearsal marks may be aligned with
2657 breakable objects such as bar lines, clef symbols, time signature
2658 symbols and key signatures. There are special properties to be
2659 found in the @code{break-aligned-interface} for positioning rehearsal
2660 marks on such objects.
2663 * Setting @code{X-offset} and @code{Y-offset} directly::
2664 * Using the @code{side-position-interface}::
2665 * Using the @code{self-alignment-interface}::
2666 * Using the @code{break-aligned-interface}::
2669 @node Setting @code{X-offset} and @code{Y-offset} directly
2670 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
2672 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
2673 properties of many objects. The following example shows three
2674 notes with the default fingering position and the positions with @code{X-offset}
2675 and @code{Y-offset} modified.
2677 @lilypond[verbatim,quote,relative=2]
2680 -\tweak #'X-offset #0
2681 -\tweak #'Y-offset #0
2684 -\tweak #'X-offset #-1
2685 -\tweak #'Y-offset #1
2691 @node Using the @code{side-position-interface}
2692 @unnumberedsubsubsec Using the @code{side-position-interface}
2694 An object which supports the @code{side-position-interface} can be
2695 placed next to its parent object so that
2696 the specified edges of the two objects touch. The object may be
2697 placed above, below, to the right or to the left of the parent.
2698 The parent cannot be specified; it is determined by the order of
2699 elements in the input stream. Most objects have the associated
2700 note head as their parent.
2702 The values of the @code{side-axis} and @code{direction} properties
2703 determine where the object is to be placed, as follows:
2705 @c TODO add an example of each to the table
2707 @multitable @columnfractions .3 .3 .3
2708 @headitem @code{side-axis} @tab @code{direction} @tab
2709 @headitem property @tab property @tab Placement
2711 @item @code{0} @tab @code{-1} @tab left
2712 @item @code{0} @tab @code{1} @tab right
2713 @item @code{1} @tab @code{-1} @tab below
2714 @item @code{1} @tab @code{1} @tab above
2718 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
2719 the procedure @code{ly:side-position-interface::x-aligned-side}.
2720 This procedure will return the correct value of @code{X-offset} to
2721 place the object to the left or right side of the parent according
2722 to value of @code{direction}.
2724 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
2725 the procedure @code{ly:side-position-interface::y-aligned-side}.
2726 This procedure will return the correct value of @code{Y-offset} to
2727 place the object to the top or bottom of the parent according
2728 to value of @code{direction}.
2730 @c TODO Add examples
2732 @node Using the @code{self-alignment-interface}
2733 @unnumberedsubsubsec Using the @code{self-alignment-interface}
2735 @emph{Self-aligning objects horizontally}
2737 The horizontal alignment of an object which supports the
2738 @code{self-alignment-interface} is controlled by the value of
2739 the @code{self-alignment-X} property, provided the object's
2740 @code{X-offset} property is set to
2741 @code{ly:self-alignment-interface::x-aligned-on-self}.
2742 @code{self-alignment-X} may be given any
2743 real value, in units of half the total X extent of the
2744 object. Negative values move the object to the right, positive
2745 to the left. A value of @code{0} centers the object on the
2746 reference point of its parent, a value of @code{-1} aligns the
2747 left edge of the object on the reference point of its parent,
2748 and a value of @code{1} aligns the right edge of the object on the
2749 reference point of its parent. The symbols @code{LEFT},
2750 @code{CENTER} and @code{RIGHT} may be used instead of the values
2751 @code{-1, 0, 1} respectively.
2753 Normally the @code{\override} command would be used to modify the
2754 value of @code{self-alignment-X}, but the @code{\tweak} command
2755 can be used to separately align several annotations on a single
2758 @lilypond[quote,verbatim,relative=1]
2760 -\tweak #'self-alignment-X #-1
2762 -\tweak #'self-alignment-X #0
2764 -\tweak #'self-alignment-X #RIGHT
2766 -\tweak #'self-alignment-X #-2.5
2767 ^"aligned further to the right"
2770 @emph{Self-aligning objects vertically}
2772 Objects may be aligned vertically in an analogous way to aligning
2773 them horizontally if the @code{Y-offset} property is set to
2774 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
2775 other mechanisms are often involved in vertical alignment: the
2776 value of @code{Y-offset} is just one variable taken into account.
2777 This may make adjusting the value of some objects tricky.
2778 The units are just half the vertical extent of the object, which
2779 is usually quite small, so quite large numbers may be required.
2780 A value of @code{-1} aligns the lower edge of the object with
2781 the reference point of the parent object, a value of @code{0}
2782 aligns the center of the object with the reference point of the
2783 parent, and a value of @code{1} aligns the top edge of the object
2784 with the reference point of the parent. The symbols @code{DOWN},
2785 @code{CENTER}, @code{UP} may be substituted for @code{-1, 0, 1}
2788 @emph{Self-aligning objects in both directions}
2790 By setting both @code{X-offset} and @code{Y-offset}, an object may
2791 be aligned in both directions simultaneously.
2793 The following example shows how to adjust a fingering mark so
2794 that it nestles close to the note head.
2796 @lilypond[quote,verbatim,relative=2]
2798 -\tweak #'self-alignment-X #0.5 % move horizontally left
2799 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
2800 -\tweak #'self-alignment-Y #-1 % move vertically up
2805 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
2807 @c Cannot document as they do not seem to operate consistently on all objects -td
2808 @c TODO investigate further
2810 The @code{aligned-on-parent} procedures are used in the same way
2811 as the @code{aligned-on-self} procedures, they difference being
2812 that they permit an object to be aligned with the @emph{edges} of
2813 the parent rather than the parent's reference point. The following
2814 example shows the difference:
2818 @lilypond[verbatim,quote]
2824 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
2826 @c Cannot document as they do not seem to operate consistently on all objects -td
2827 @c TODO investigate further
2831 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
2833 @node Using the @code{break-aligned-interface}
2834 @unnumberedsubsubsec Using the @code{break-aligned-interface}
2836 Rehearsal marks may be aligned with notation objects other
2837 than bar lines. These objects include @code{ambitus},
2838 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
2839 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
2840 @code{time-signature}.
2842 By default, rehearsal marks will be horizontally centered above the
2845 @lilypond[verbatim,quote,relative=1]
2847 % the RehearsalMark will be centered above the Clef
2848 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
2853 % the RehearsalMark will be centered above the TimeSignature
2854 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
2862 The alignment of the rehearsal mark relative to the notation object
2863 can be changed, as shown in the following example. In a score with
2864 multiple staves, this setting should be done for all the staves.
2866 @lilypond[verbatim,quote,relative=1]
2867 % The RehearsalMark will be centered above the KeySignature
2868 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
2874 % The RehearsalMark will be aligned with the left edge of the KeySignature
2875 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
2879 % The RehearsalMark will be aligned with the right edge of the KeySignature
2880 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
2886 The rehearsal mark can also be offset to the right or left of the left edge
2887 by an arbitrary amount. The units are staff-spaces:
2889 @lilypond[verbatim,quote,relative=1]
2890 % The RehearsalMark will be aligned with the left edge of the KeySignature
2891 % and then shifted right by 3.5 staff-spaces
2892 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
2893 \once \override Score.KeySignature #'break-align-anchor = #3.5
2897 % The RehearsalMark will be aligned with the left edge of the KeySignature
2898 % and then shifted left by 2 staff-spaces
2899 \once \override Score.KeySignature #'break-align-anchor = #-2
2907 @node Vertical grouping of grobs
2908 @subsection Vertical grouping of grobs
2910 @c FIXME Expand this section
2912 The VerticalAlignment and VerticalAxisGroup grobs work together.
2913 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
2914 etc. VerticalAlignment then vertically aligns the different grobs
2915 grouped together by VerticalAxisGroup. There is usually only one
2916 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
2920 @node Modifying stencils
2921 @subsection Modifying stencils
2923 All layout objects have a @code{stencil} property which is part of
2924 the @code{grob-interface}. By default, this property is usually
2925 set to a function specific to the object that is tailor-made to
2926 render the symbol which represents it in the output. For example,
2927 the standard setting for the @code{stencil} property of the
2928 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
2930 The standard symbol for any object can be replaced by modifying the
2931 @code{stencil} property to reference a different, specially-written,
2932 procedure. This requires a high level of knowledge of the internal
2933 workings of LilyPond, but there is an easier way which can often
2934 produce adequate results.
2936 This is to set the @code{stencil} property to the procedure which
2937 prints text -- @code{ly:text-interface::print} -- and to add a
2938 @code{text} property to the object which is set to contain the
2939 markup text which produces the required symbol. Due to the
2940 flexibility of markup, much can be achieved -- see in particular
2941 @ref{Graphic notation inside markup}.
2943 The following example demonstrates this by changing the note head
2944 symbol to a cross within a circle.
2946 @lilypond[verbatim,quote]
2948 \once \override NoteHead #'stencil = #ly:text-interface::print
2949 \once \override NoteHead #'text = \markup {
2951 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
2952 \musicglyph #"noteheads.s2cross"
2960 Any of the glyphs in the feta Font can be supplied to the
2961 @code{\musicglyph} markup command -- see @ref{The Feta font}.
2963 @c TODO Add inserting eps files or ref to later
2965 @c TODO Add inserting Postscript or ref to later
2970 @ref{Graphic notation inside markup},
2971 @ref{Formatting text},
2972 @ref{Text markup commands},
2973 @ref{The Feta font}.
2976 @node Modifying shapes
2977 @subsection Modifying shapes
2980 * Modifying ties and slurs::
2983 @node Modifying ties and slurs
2984 @unnumberedsubsubsec Modifying ties and slurs
2986 Ties, slurs and phrasing slurs are drawn as third-order Bézier
2987 curves. If the shape of the tie or slur which is calculated
2988 automatically is not optimum, the shape may be modified manually by
2989 explicitly specifying the four control points required to define
2990 a third-order Bézier curve.
2992 Third-order or cubic Bézier curves are defined by four control
2993 points. The first and fourth control points are precisely the
2994 starting and ending points of the curve. The intermediate two
2995 control points define the shape. Animations showing how the curve
2996 is drawn can be found on the web, but the following description
2997 may be helpful. The curve starts from the first control point
2998 heading directly towards the second, gradually bending over to
2999 head towards the third and continuing to bend over to head towards
3000 the fourth, arriving there travelling directly from the third
3001 control point. The curve is entirely contained in the
3002 quadrilateral defined by the four control points.
3004 Here is an example of a case where the tie is not optimum, and
3005 where @code{\tieDown} would not help.
3007 @lilypond[verbatim,quote,relative=1]
3011 { r4 <g c,> <g c,> <g c,> }
3015 One way of improving this tie is to manually modify its control
3018 The coordinates of the Bézier control points are specified in units
3019 of staff-spaces. The X@tie{}coordinate is relative to the reference
3020 point of the note to which the tie or slur is attached, and the
3021 Y@tie{}coordinate is relative to the staff center line. The
3022 coordinates are entered as a list of four pairs of decimal numbers
3023 (reals). One approach is to estimate the coordinates of the two
3024 end points, and then guess the two intermediate points. The optimum
3025 values are then found by trial and error.
3027 It is useful to remember that a symmetric curve requires symmetric
3028 control points, and that Bézier curves have the useful property that
3029 transformations of the curve such as translation, rotation and
3030 scaling can be achieved by applying the same transformation to the
3031 curve's control points.
3033 For the example above the following override gives a satisfactory
3036 @lilypond[verbatim,quote,relative=1]
3039 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3042 { r4 <g c,> <g c,> <g c,>4 }
3048 It is not possible to modify shapes of ties or slurs by changing
3049 the @code{control-points} property if there are more than one at
3050 the same musical moment, not even by using the @code{\tweak}