1 @c -*- coding: utf-8; mode: texinfo; -*-
2 @c This file is part of lilypond.tely
4 Translation of GIT committish: FILL-IN-HEAD-COMMITTISH
6 When revising a translation, copy the HEAD committish of the
7 version that you are working on. See TRANSLATION for details.
12 @node Changing defaults
13 @chapter Changing defaults
15 The purpose of LilyPond's design is to provide the finest quality
16 output by default. Nevertheless, it may happen that you need to
17 change this default layout. The layout is controlled through a large
18 number of @q{knobs and switches} collectively called @q{properties}.
19 A tutorial introduction to accessing and modifying these properties
20 can be found in the Learning Manual, see @rlearning{Tweaking output}.
21 This should be read first. This chapter covers similar ground, but
22 in a style more appropriate to a reference manual.
24 @cindex Internals Reference
26 The definitive description of the controls available for tuning can
27 be found in a separate document: @rinternalsnamed{Top,the Internals
28 Reference}. That manual lists all the variables, functions and
29 options available in LilyPond. It is written as a HTML document,
31 @c leave the @uref as one long line.
32 @uref{http://@/lilypond@/.org/@/doc/@/stable/@/Documentation/@/user/@/lilypond@/-internals/,on@/-line},
33 and is also included with the LilyPond documentation package.
35 Internally, LilyPond uses Scheme (a LISP dialect) to provide
36 infrastructure. Overriding layout decisions in effect accesses the
37 program internals, which requires Scheme input. Scheme elements are
38 introduced in a @code{.ly} file with the hash mark
39 @code{#}.@footnote{@rlearning{Scheme tutorial}, contains a short tutorial
40 on entering numbers, lists, strings, and symbols in Scheme.}
44 * Interpretation contexts::
45 * Explaining the Internals Reference::
46 * Modifying properties::
47 * Useful concepts and properties::
52 @node Interpretation contexts
53 @section Interpretation contexts
55 This section describes what contexts are, and how to modify them.
58 * Contexts explained::
60 * Modifying context plug-ins::
61 * Changing context default settings::
62 * Defining new contexts::
69 @rlearning{Contexts and engravers}.
72 @file{ly/@/engraver@/-init@/.ly},
73 @file{ly/@/performer@/-init@/.ly}.
76 @rlsr{Contexts and engravers}.
79 @rinternals{Contexts},
80 @rinternals{Engravers and Performers}.
83 @node Contexts explained
84 @subsection Contexts explained
87 @c TODO Rethink and rewrite
89 >> > > - list of contexts: my *danger unmaintainable*
90 >> > > alarm just went off. I'm
92 I knew it would... And leaving out some of them is perfectly fine
94 I do think that a list like this, with the main contexts and a
96 description of what they do (perhaps also with a note about what
98 behavior is associated with each of them, but this may be
100 should be there, and then we could simply list the remaining ones
102 further explanation and with links to the IR.
105 @c TODO Improve layout, order and consistency of wording -td
107 @c TODO Add introduction which explains contexts in generality -td
109 @c TODO Describe propagation of property values -td
111 Contexts are arranged hierarchically:
114 * Score - the master of all contexts::
115 * Top-level contexts - staff containers::
116 * Intermediate-level contexts - staves::
117 * Bottom-level contexts - voices::
120 @node Score - the master of all contexts
121 @unnumberedsubsubsec Score - the master of all contexts
123 This is the top level notation context. No other context can
124 contain a Score context. By default the Score context handles
125 the administration of time signatures and makes sure that items
126 such as clefs, time signatures, and key-signatures are aligned
129 A Score context is instantiated implicitly when a
130 @code{\score @{@dots{}@}} or @code{\layout @{@dots{}@}} block is
131 processed, or explicitly when a @code{\new Score} command is
134 @node Top-level contexts - staff containers
135 @unnumberedsubsubsec Top-level contexts - staff containers
137 @strong{@emph{StaffGroup}}
139 Groups staves while adding a bracket on the left side, grouping
140 the staves together. The bar lines of the contained staves are
141 connected vertically. @code{StaffGroup} only consists of a collection
142 of staves, with a bracket in front and spanning bar lines.
144 @strong{@emph{ChoirStaff}}
146 Identical to @code{StaffGroup} except that the bar lines of the
147 contained staves are not connected vertically.
149 @strong{@emph{GrandStaff}}
151 A group of staves, with a brace on the left side, grouping the
152 staves together. The bar lines of the contained staves are
153 connected vertically.
155 @strong{@emph{PianoStaff}}
157 Just like @code{GrandStaff}, but with support for instrument names
158 to the left of each system.
160 @node Intermediate-level contexts - staves
161 @unnumberedsubsubsec Intermediate-level contexts - staves
163 @strong{@emph{Staff}}
165 Handles clefs, bar lines, keys, accidentals. It can contain
166 @code{Voice} contexts.
168 @strong{@emph{RhythmicStaff}}
170 Like @code{Staff} but for printing rhythms. Pitches are ignored;
171 the notes are printed on one line.
173 @strong{@emph{TabStaff}}
175 Context for generating tablature. By default lays the music
176 expression out as a guitar tablature, printed on six lines.
178 @strong{@emph{DrumStaff}}
180 Handles typesetting for percussion. Can contain @code{DrumVoice}
182 @strong{@emph{VaticanaStaff}}
184 Same as @code{Staff}, except that it is designed for typesetting
185 a piece in gregorian style.
187 @strong{@emph{MensuralStaff}}
189 Same as @code{Staff}, except that it is designed for typesetting
190 a piece in mensural style.
192 @node Bottom-level contexts - voices
193 @unnumberedsubsubsec Bottom-level contexts - voices
195 Voice-level contexts initialise certain properties and start
196 appropriate engravers. Being bottom-level contexts, they cannot
197 contain other contexts.
199 @strong{@emph{Voice}}
201 Corresponds to a voice on a staff. This context handles the
202 conversion of dynamic signs, stems, beams, super- and sub-scripts,
203 slurs, ties, and rests. You have to instantiate this explicitly
204 if you require multiple voices on the same staff.
206 @strong{@emph{VaticanaVoice}}
208 Same as @code{Voice}, except that it is designed for typesetting
209 a piece in gregorian style.
211 @strong{@emph{MensuralVoice}}
213 Same as @code{Voice}, with modifications for typesetting a piece in
216 @strong{@emph{Lyrics}}
218 Corresponds to a voice with lyrics. Handles the printing of a
219 single line of lyrics.
221 @strong{@emph{DrumVoice}}
223 The voice context used in a percussion staff.
225 @strong{@emph{FiguredBass}}
227 The context in which @code{BassFigure} objects are created from
228 input entered in @code{\figuremode} mode.
230 @strong{@emph{TabVoice}}
232 The voice context used within a @code{TabStaff} context. Usually
233 left to be created implicitly.
235 @strong{@emph{ChordNames}}
237 Typesets chord names.
242 Then the following, which I don't know what to do with:
244 * GregorianTranscriptionVoice
245 * GregorianTranscriptionStaff
248 Engraves fretboards from chords. Not easy... Not
250 There is now some documentation on FretBoards in the NR, under
251 instrument-specific notation -- cds.
255 * CueVoice Not documented
257 Hard coded entry point for LilyPond. Cannot be tuned.
259 Silently discards all musical information given to this
264 @node Creating contexts
265 @subsection Creating contexts
267 @c TODO \new Score and \score
268 @c TODO more complete descriptions rather than learning style
270 For scores with only one voice and one staff, contexts are
271 created automatically. For more complex scores, it is necessary to
272 create them by hand. There are three commands that do this.
277 The easiest command is @code{\new}, and it also the quickest to type.
278 It is prepended to a music expression, for example
282 @cindex Context, creating
285 \new @var{type} @var{music expression}
289 where @var{type} is a context name (like @code{Staff} or
290 @code{Voice}). This command creates a new context, and starts
291 interpreting the @var{music expression} with that.
293 A practical application of @code{\new} is a score with many
294 staves. Each part that should be on its own staff, is preceded with
297 @lilypond[quote,verbatim,relative=2,ragged-right,fragment]
304 The @code{\new} command may also give a name to the context,
307 \new @var{type} = @var{id} @var{music}
309 However, this user specified name is only used if there is no other
310 context already earlier with the same name.
316 Like @code{\new}, the @code{\context} command also directs a music
317 expression to a context object, but gives the context an explicit name. The
321 \context @var{type} = @var{id} @var{music}
324 This form will search for an existing context of type @var{type}
325 called @var{id}. If that context does not exist yet, a new
326 context with the specified name is created. This is useful if
327 the context is referred to later on. For example, when
328 setting lyrics the melody is in a named context
331 \context Voice = "@b{tenor}" @var{music}
335 so the texts can be properly aligned to its notes,
338 \new Lyrics \lyricsto "@b{tenor}" @var{lyrics}
343 Another possible use of named contexts is funneling two different
344 music expressions into one context. In the following example,
345 articulations and notes are entered separately,
349 arts = @{ s4-. s4-> @}
352 They are combined by sending both to the same @code{Voice} context,
356 \new Staff \context Voice = "A" \music
357 \context Voice = "A" \arts
360 @lilypond[quote,ragged-right]
364 \new Staff \context Voice = "A" \music
365 \context Voice = "A" \arts
369 With this mechanism, it is possible to define an Urtext (original
370 edition), with the option to put several distinct articulations on the
373 @cindex creating contexts
376 The third command for creating contexts is
378 \context @var{type} @var{music}
383 This is similar to @code{\context} with @code{= @var{id}}, but matches
384 any context of type @var{type}, regardless of its given name.
386 This variant is used with music expressions that can be interpreted at
387 several levels. For example, the @code{\applyOutput} command (see
388 @ref{Running a function on all layout objects}). Without an explicit
389 @code{\context}, it is usually applied to @code{Voice}
392 \applyOutput #'@var{context} #@var{function} % apply to Voice
395 To have it interpreted at the @code{Score} or @code{Staff} level use
399 \applyOutput #'Score #@var{function}
400 \applyOutput #'Staff #@var{function}
406 @node Modifying context plug-ins
407 @subsection Modifying context plug-ins
409 @c TODO Should this be Modifying engravers or Modifying contexts?
411 Notation contexts (like @code{Score} and @code{Staff}) not only
413 they also contain plug-ins called @q{engravers} that create notation
414 elements. For example, the @code{Voice} context contains a
415 @code{Note_head_engraver} and the @code{Staff} context contains a
416 @code{Key_signature_engraver}.
418 For a full a description of each plug-in, see
420 @rinternals{Engravers and Performers}.
423 Internals Reference @expansion{} Translation @expansion{} Engravers.
425 Every context described in
427 @rinternals{Contexts}
430 Internals Reference @expansion{} Translation @expansion{} Context.
432 lists the engravers used for that context.
435 It can be useful to shuffle around these plug-ins. This is done by
436 starting a new context with @code{\new} or @code{\context}, and
442 \new @var{context} \with @{
455 where the @dots{} should be the name of an engraver. Here is a simple
456 example which removes @code{Time_signature_engraver} and
457 @code{Clef_engraver} from a @code{Staff} context,
459 @lilypond[quote,relative=1,verbatim,fragment]
465 \remove "Time_signature_engraver"
466 \remove "Clef_engraver"
473 In the second staff there are no time signature or clef symbols. This
474 is a rather crude method of making objects disappear since it will affect
475 the entire staff. This method also influences the spacing, which may or
476 may not be desirable. More sophisticated methods of blanking objects
477 are shown in @rlearning{Visibility and color of objects}.
479 The next example shows a practical application. Bar lines and time
480 signatures are normally synchronized across the score. This is done
481 by the @code{Timing_translator} and @code{Default_bar_line_engraver}.
482 This plug-in keeps an administration of time signature, location
483 within the measure, etc. By moving these engraver from @code{Score} to
484 @code{Staff} context, we can have a score where each staff has its own
487 @cindex polymetric scores
488 @cindex Time signatures, multiple
490 @lilypond[quote,relative=1,ragged-right,verbatim,fragment]
492 \remove "Timing_translator"
493 \remove "Default_bar_line_engraver"
496 \consists "Timing_translator"
497 \consists "Default_bar_line_engraver"
503 \consists "Timing_translator"
504 \consists "Default_bar_line_engraver"
514 Usually the order in which the engravers are specified
515 does not matter, but in a few special cases the order
516 is important, for example where one engraver writes
517 a property and another reads it, or where one engraver
518 creates a grob and another must process it. The order in
519 which the engravers are specified is the order in which
520 they are called to carry out their processing.
522 The following orderings are important: the
523 @code{Bar_engraver} must normally be first, and
524 the @code{New_fingering_engraver} must come before
525 the @code{Script_column_engraver}. There may be others
526 with ordering dependencies.
528 @node Changing context default settings
529 @subsection Changing context default settings
531 The context settings which are to be used by default in
532 @code{Score}, @code{Staff} and @code{Voice} contexts may be specified
533 in a @code{\layout} block, as illustrated in the following example.
534 The @code{\layout} block should be placed within the @code{\score}
535 block to which it is to apply, but outside any music.
537 Note that the @code{\set} command itself and the context must be
538 omitted when the context default values are specified in this way:
540 @lilypond[quote,verbatim]
543 a4^"Really small, thicker stems, no time signature" a a a
550 \override Stem #'thickness = #4.0
551 \remove "Time_signature_engraver"
557 In this example, the @code{\Staff} command specifies that the
558 subsequent specifications are to be applied to all staves within
561 Modifications can be made to the @code{Score} context or all
562 @code{Voice} contexts in a similar way.
566 It is not possible to collect context changes in a variable and apply
567 them to a @code{\context} definition by referring to that variable.
569 The @code{\RemoveEmptyStaffContext} will overwrite your current
570 @code{\Staff} settings. If you wish to change the defaults for a
571 staff which uses @code{\RemoveEmptyStaffContext}, you must do so
572 after calling @code{\RemoveEmptyStaffContext}, ie
577 \RemoveEmptyStaffContext
579 \override Stem #'thickness = #4.0
584 @c TODO: add \with in here.
588 @node Defining new contexts
589 @subsection Defining new contexts
591 Specific contexts, like @code{Staff} and @code{Voice}, are made of
592 simple building blocks. It is possible to create new types of
593 contexts with different combinations of engraver plug-ins.
595 The next example shows how to build a different type of
596 @code{Voice} context from scratch. It will be similar to
597 @code{Voice}, but only prints centered slash note heads. It can be used
598 to indicate improvisation in jazz pieces,
600 @lilypond[quote,ragged-right]
603 \type "Engraver_group"
604 \consists "Note_heads_engraver"
605 \consists "Text_engraver"
606 \consists Pitch_squash_engraver
607 squashedPosition = #0
608 \override NoteHead #'style = #'slash
609 \override Stem #'transparent = ##t
613 \accepts "ImproVoice"
617 a4 d8 bes8 \new ImproVoice { c4^"ad lib" c
618 c4 c^"undress" c_"while playing :)" c }
624 These settings are defined within a @code{\context} block inside a
625 @code{\layout} block,
635 In the following discussion, the example input shown should go in place
636 of the @dots{} in the previous fragment.
638 First it is necessary to define a name for the new context:
644 Since it is similar to the @code{Voice}, we want commands that work
645 on (existing) @code{Voice}s to remain working. This is achieved by
646 giving the new context an alias @code{Voice},
652 The context will print notes and instructive texts, so we need to add
653 the engravers which provide this functionality,
656 \consists Note_heads_engraver
657 \consists Text_engraver
660 but we only need this on the center line,
663 \consists Pitch_squash_engraver
664 squashedPosition = #0
667 The @rinternals{Pitch_squash_engraver} modifies note heads (created
668 by @rinternals{Note_heads_engraver}) and sets their vertical
669 position to the value of @code{squashedPosition}, in this case@tie{}@code{0},
672 The notes look like a slash, and have no stem,
675 \override NoteHead #'style = #'slash
676 \override Stem #'transparent = ##t
679 All these plug-ins have to cooperate, and this is achieved with a
680 special plug-in, which must be marked with the keyword @code{\type}.
681 This should always be @code{Engraver_group}.
684 \type "Engraver_group"
692 \type "Engraver_group"
693 \consists "Note_heads_engraver"
694 \consists "Text_engraver"
695 \consists Pitch_squash_engraver
696 squashedPosition = #0
697 \override NoteHead #'style = #'slash
698 \override Stem #'transparent = ##t
704 Contexts form hierarchies. We want to hang the @code{ImproVoice}
705 under @code{Staff}, just like normal @code{Voice}s. Therefore, we
706 modify the @code{Staff} definition with the @code{\accepts}
717 The opposite of @code{\accepts} is @code{\denies},
718 which is sometimes needed when reusing existing context definitions.
720 Putting both into a @code{\layout} block, like
730 \accepts "ImproVoice"
735 Then the output at the start of this subsection can be entered as
743 c c_"while playing :)"
750 @node Aligning contexts
751 @subsection Aligning contexts
753 New contexts may be aligned above or below existing contexts. This
754 could be useful in setting up a vocal staff (@rlearning{Vocal ensembles}) and
757 @c TODO Better example needed. Ref LM, and expand on it.
760 @funindex alignAboveContext
761 @funindex alignBelowContext
763 @lilypond[quote,ragged-right]
766 \relative c' \new Staff = "main" {
769 \new Staff \with {alignAboveContext=main} \ossia
776 @cindex nested contexts
777 @cindex contexts, nested
782 Contexts like @code{PianoStaff} can contain other contexts
783 nested within them. Contexts which are acceptable for nesting
784 are defined by the @qq{accepts} list of a context. Contexts
785 which are not in this list are placed below the outer context
786 in the printed score.
787 For example, the @code{PianoStaff} context is defined by default
788 to accept @code{Staff} and @code{FiguredBass} contexts within
789 it, but not (for example) a @code{Lyrics} context. So in the
790 following structure the lyrics are placed below the piano staff
791 rather than between the two staves:
793 @lilypond[verbatim,quote,relative=1]
796 \new Staff { e4 d c2 }
797 \addlyrics { Three blind mice }
805 The @qq{accepts} list of a context can be modified to include
806 additional nested contexts, so if we wanted the lyrics to appear
807 between the two staves we could use:
809 @lilypond[verbatim,quote,relative=1]
810 \new PianoStaff \with { \accepts Lyrics }
812 \new Staff { e4 d c2 }
813 \addlyrics { Three blind mice }
821 The opposite of @code{\accepts} is @code{\denies}; this removes a
822 context from the @qq{accepts} list.
824 @node Explaining the Internals Reference
825 @section Explaining the Internals Reference
829 * Navigating the program reference::
830 * Layout interfaces::
831 * Determining the grob property::
832 * Naming conventions::
835 @node Navigating the program reference
836 @subsection Navigating the program reference
838 @c TODO remove this (it's in the LM)
839 @c Replace with more factual directions
841 Suppose we want to move the fingering indication in the fragment
844 @lilypond[quote,fragment,relative=2,verbatim]
850 If you visit the documentation on fingering instructions (in
851 @ref{Fingering instructions}), you will notice:
856 Internals Reference: @rinternals{Fingering}.
861 @c outdated info; probably will delete.
863 This fragment points to two parts of the program reference: a page
864 on @code{FingeringEvent} and one on @code{Fingering}.
866 The page on @code{FingeringEvent} describes the properties of the music
867 expression for the input @code{-2}. The page contains many links
868 forward. For example, it says
871 Accepted by: @rinternals{Fingering_engraver},
875 That link brings us to the documentation for the Engraver, the
879 This engraver creates the following layout objects: @rinternals{Fingering}.
882 In other words, once the @code{FingeringEvent}s are interpreted, the
883 @code{Fingering_engraver} plug-in will process them.
887 @c I can't figure out what this is supposed to mean. -gp
889 The @code{Fingering_engraver} is also listed to create
890 @rinternals{Fingering} objects,
892 @c old info? it doesn't make any sense to me with our current docs.
894 second bit of information listed under @b{See also} in the Notation
899 The programmer's reference is available as an HTML document. It is
900 highly recommended that you read it in HTML form, either online or
901 by downloading the HTML documentation. This section will be much more
902 difficult to understand if you are using the
906 Follow the link to @rinternals{Fingering}. At the top of the
910 Fingering objects are created by: @rinternals{Fingering_engraver} and
911 @rinternals{New_fingering_engraver}.
914 By following related links inside the program reference, we can follow the
915 flow of information within the program:
919 @item @rinternals{Fingering}:
920 @rinternals{Fingering} objects are created by:
921 @rinternals{Fingering_engraver}
923 @item @rinternals{Fingering_engraver}:
924 Music types accepted: @rinternals{fingering-event}
926 @item @rinternals{fingering-event}:
927 Music event type @code{fingering-event} is in Music expressions named
928 @rinternals{FingeringEvent}
931 This path goes against the flow of information in the program: it
932 starts from the output, and ends at the input event. You could
933 also start at an input event, and read with the flow of
934 information, eventually ending up at the output object(s).
936 The program reference can also be browsed like a normal document. It
939 @rinternals{Music definitions},
942 @code{Music definitions}
944 on @rinternals{Translation}, and the @rinternals{Backend}. Every
945 chapter lists all the definitions used and all properties that may be
949 @node Layout interfaces
950 @subsection Layout interfaces
952 @cindex interface, layout
953 @cindex layout interface
956 The HTML page that we found in the previous section describes the
957 layout object called @rinternals{Fingering}. Such an object is a
958 symbol within the score. It has properties that store numbers (like
959 thicknesses and directions), but also pointers to related objects. A
960 layout object is also called a @emph{Grob}, which is short for Graphical
961 Object. For more details about Grobs, see @rinternals{grob-interface}.
963 The page for @code{Fingering} lists the definitions for the
964 @code{Fingering} object. For example, the page says
967 @code{padding} (dimension, in staff space):
973 which means that the number will be kept at a distance of at least 0.5
977 Each layout object may have several functions as a notational or
978 typographical element. For example, the Fingering object
979 has the following aspects
983 Its size is independent of the horizontal spacing, unlike slurs or beams.
986 It is a piece of text. Granted, it is usually a very short text.
989 That piece of text is typeset with a font, unlike slurs or beams.
992 Horizontally, the center of the symbol should be aligned to the
993 center of the note head.
996 Vertically, the symbol is placed next to the note and the staff.
999 The vertical position is also coordinated with other superscript
1000 and subscript symbols.
1003 Each of these aspects is captured in so-called @emph{interface}s,
1004 which are listed on the @rinternals{Fingering} page at the bottom
1007 This object supports the following interfaces:
1008 @rinternals{item-interface},
1009 @rinternals{self-alignment-interface},
1010 @rinternals{side-position-interface}, @rinternals{text-interface},
1011 @rinternals{text-script-interface}, @rinternals{font-interface},
1012 @rinternals{finger-interface}, and @rinternals{grob-interface}.
1015 Clicking any of the links will take you to the page of the respective
1016 object interface. Each interface has a number of properties. Some of
1017 them are not user-serviceable (@q{Internal properties}), but others
1020 We have been talking of @emph{the} @code{Fingering} object, but actually it
1021 does not amount to much. The initialization file (see
1022 @rlearning{Other sources of information})
1023 @file{scm/@/define@/-grobs@/.scm} shows the soul of the @q{object},
1028 (avoid-slur . around)
1029 (slur-padding . 0.2)
1030 (staff-padding . 0.5)
1031 (self-alignment-X . 0)
1032 (self-alignment-Y . 0)
1033 (script-priority . 100)
1034 (stencil . ,ly:text-interface::print)
1035 (direction . ,ly:script-interface::calc-direction)
1036 (font-encoding . fetaNumber)
1037 (font-size . -5) ; don't overlap when next to heads.
1038 (meta . ((class . Item)
1039 (interfaces . (finger-interface
1041 text-script-interface
1043 side-position-interface
1044 self-alignment-interface
1045 item-interface))))))
1049 As you can see, the @code{Fingering} object is nothing more than a
1050 bunch of variable settings, and the webpage in the Internals Reference
1051 is directly generated from this definition.
1054 @node Determining the grob property
1055 @subsection Determining the grob property
1057 @c TODO remove this (it's in the LM)
1058 @c Replace with more factual directions
1060 Recall that we wanted to change the position of the @b{2} in
1062 @lilypond[quote,fragment,relative=2,verbatim]
1068 Since the @b{2} is vertically positioned next to its note, we have to
1069 meddle with the interface associated with this positioning. This is
1070 done using @code{side-position-interface}. The page for this interface
1074 @code{side-position-interface}
1076 Position a victim object (this one) next to other objects (the
1077 support). The property @code{direction} signifies where to put the
1078 victim object relative to the support (left or right, up or down?)
1083 Below this description, the variable @code{padding} is described as
1088 (dimension, in staff space)
1090 Add this much extra space between objects that are next to each other.
1094 By increasing the value of @code{padding}, we can move the
1095 fingering away from the note head. The following command inserts
1096 3 staff spaces of white
1097 between the note and the fingering:
1099 \once \override Voice.Fingering #'padding = #3
1102 Inserting this command before the Fingering object is created,
1103 i.e., before @code{c2}, yields the following result:
1105 @lilypond[quote,relative=2,fragment,verbatim]
1106 \once \override Voice.Fingering #'padding = #3
1113 In this case, the context for this tweak is @code{Voice}. This
1114 fact can also be deduced from the program reference, for the page for
1115 the @rinternals{Fingering_engraver} plug-in says
1118 Fingering_engraver is part of contexts: @dots{} @rinternals{Voice}
1122 @node Naming conventions
1123 @subsection Naming conventions
1125 Another thing that is needed, is an overview of the various naming
1128 scheme functions: lowercase-with-hyphens (incl. one-word
1130 scheme functions: ly:plus-scheme-style
1131 music events, music classes and music properties:
1133 Grob interfaces: scheme-style
1134 backend properties: scheme-style (but X and Y!)
1135 contexts (and MusicExpressions and grobs): Capitalized or
1137 context properties: lowercaseFollowedByCamelCase
1139 Capitalized_followed_by_lowercase_and_with_underscores
1141 Which of these are conventions and which are rules?
1142 Which are rules of the underlying language, and which are
1146 @node Modifying properties
1147 @section Modifying properties
1149 @c TODO change the menu and subsection node names to use
1150 @c backslash once the new macro to handle the refs
1151 @c is available. Need to find and change all refs at
1152 @c the same time. -td
1155 * Overview of modifying properties::
1157 * The override command::
1158 * The tweak command::
1159 * set versus override::
1163 @node Overview of modifying properties
1164 @subsection Overview of modifying properties
1166 Each context is responsible for creating certain types of graphical
1167 objects. The settings used for printing these objects are also stored by
1168 context. By changing these settings, the appearance of objects can be
1171 The syntax for this is
1174 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1177 Here @var{name} is the name of a graphical object, like
1178 @code{Stem} or @code{NoteHead}, and @var{property} is an internal
1179 variable of the formatting system (@q{grob property} or @q{layout
1180 property}). The latter is a symbol, so it must be quoted. The
1181 subsection @ref{Modifying properties}, explains what to fill in
1182 for @var{name}, @var{property}, and @var{value}. Here we only
1183 discuss the functionality of this command.
1188 \override Staff.Stem #'thickness = #4.0
1192 makes stems thicker (the default is 1.3, with staff line thickness as a
1193 unit). Since the command specifies @code{Staff} as context, it only
1194 applies to the current staff. Other staves will keep their normal
1195 appearance. Here we see the command in action:
1197 @lilypond[quote,verbatim,relative=2,fragment]
1199 \override Staff.Stem #'thickness = #4.0
1205 The @code{\override} command changes the definition of the @code{Stem}
1206 within the current @code{Staff}. After the command is interpreted
1207 all stems are thickened.
1209 Analogous to @code{\set}, the @var{context} argument may be left out,
1210 causing the default context @code{Voice} to be used. Adding
1211 @code{\once} applies the change during one timestep only.
1213 @lilypond[quote,fragment,verbatim,relative=2]
1215 \once \override Stem #'thickness = #4.0
1220 The @code{\override} must be done before the object is
1221 started. Therefore, when altering @emph{Spanner} objects such as slurs
1222 or beams, the @code{\override} command must be executed at the moment
1223 when the object is created. In this example,
1225 @lilypond[quote,fragment,verbatim,relative=2]
1226 \override Slur #'thickness = #3.0
1228 \override Beam #'thickness = #0.6
1233 the slur is fatter but the beam is not. This is because the command for
1234 @code{Beam} comes after the Beam is started, so it has no effect.
1236 Analogous to @code{\unset}, the @code{\revert} command for a context
1237 undoes an @code{\override} command; like with @code{\unset}, it only
1238 affects settings that were made in the same context. In other words, the
1239 @code{\revert} in the next example does not do anything.
1242 \override Voice.Stem #'thickness = #4.0
1243 \revert Staff.Stem #'thickness
1246 Some tweakable options are called @q{subproperties} and reside inside
1247 properties. To tweak those, use commands of the form
1249 @c leave this as a long long
1251 \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value}
1258 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1263 Internals: @rinternals{OverrideProperty}, @rinternals{RevertProperty},
1264 @rinternals{PropertySet}, @rinternals{Backend}, and
1265 @rinternals{All layout objects}.
1270 The back-end is not very strict in type-checking object properties.
1271 Cyclic references in Scheme values for properties can cause hangs
1272 or crashes, or both.
1276 @node The set command
1277 @subsection The @code{\set} command
1281 @cindex changing properties
1283 Each context can have different @emph{properties}, variables contained
1284 in that context. They can be changed during the interpretation step.
1285 This is achieved by inserting the @code{\set} command in the music,
1288 \set @var{context}.@var{prop} = #@var{value}
1292 @lilypond[quote,verbatim,relative=2,fragment]
1294 \set Score.skipBars = ##t
1298 This command skips measures that have no notes. The result is that
1299 multi-rests are condensed. The value assigned is a Scheme object. In
1300 this case, it is @code{#t}, the boolean True value.
1302 If the @var{context} argument is left out, then the current bottom-most
1303 context (typically @code{ChordNames}, @code{Voice}, or
1304 @code{Lyrics}) is used. In this example,
1306 @lilypond[quote,verbatim,relative=2,fragment]
1308 \set autoBeaming = ##f
1313 the @var{context} argument to @code{\set} is left out, so automatic
1314 beaming is switched off in the current @rinternals{Voice}. Note that
1315 the bottom-most context does not always contain the property that you
1316 wish to change -- for example, attempting to set the @code{skipBars}
1317 property (of the bottom-most context, in this case @code{Voice}) will
1320 @lilypond[quote,verbatim,relative=2,fragment]
1326 Contexts are hierarchical, so if a bigger context was specified, for
1327 example @code{Staff}, then the change would also apply to all
1328 @code{Voice}s in the current stave. The change is applied
1329 @q{on-the-fly}, during the music, so that the setting only affects the
1330 second group of eighth notes.
1334 There is also an @code{\unset} command,
1336 \unset @var{context}.@var{prop}
1340 which removes the definition of @var{prop}. This command removes
1341 the definition only if it is set in @var{context}, so
1344 \set Staff.autoBeaming = ##f
1348 introduces a property setting at @code{Staff} level. The setting also
1349 applies to the current @code{Voice}. However,
1352 \unset Voice.autoBeaming
1356 does not have any effect. To cancel this setting, the @code{\unset}
1357 must be specified on the same level as the original @code{\set}. In
1358 other words, undoing the effect of @code{Staff.autoBeaming = ##f}
1361 \unset Staff.autoBeaming
1364 Like @code{\set}, the @var{context} argument does not have to be
1365 specified for a bottom context, so the two statements
1368 \set Voice.autoBeaming = ##t
1369 \set autoBeaming = ##t
1377 Settings that should only apply to a single time-step can be entered
1378 with @code{\once}, for example in
1380 @lilypond[quote,verbatim,relative=2,fragment]
1382 \once \set fontSize = #4.7
1387 the property @code{fontSize} is unset automatically after the second
1390 A full description of all available context properties is in the
1391 program reference, see
1393 @rinternals{Tunable context properties}.
1396 Translation @expansion{} Tunable context properties.
1401 @node The override command
1402 @subsection The @code{\override} command
1404 Commands which change output generally look like
1407 \override Voice.Stem #'thickness = #3.0
1411 To construct this tweak we must determine these bits of information:
1414 @item the context: here @code{Voice}.
1415 @item the layout object: here @code{Stem}.
1416 @item the layout property: here @code{thickness}.
1417 @item a sensible value: here @code{3.0}.
1420 Some tweakable options are called @q{subproperties} and reside inside
1421 properties. To tweak those, use commands in the form
1424 \override Stem #'(details beamed-lengths) = #'(4 4 3)
1427 @cindex internal documentation
1428 @cindex finding graphical objects
1429 @cindex graphical object descriptions
1432 @cindex internal documentation
1434 For many properties, regardless of the data type of the property, setting the
1435 property to false ( @code{##f} ) will result in turning it off, causing
1436 LilyPond to ignore that property entirely. This is particularly useful for
1437 turning off grob properties which may otherwise be causing problems.
1439 We demonstrate how to glean this information from the notation manual
1440 and the program reference.
1443 @node The tweak command
1444 @subsection The @code{\tweak} command
1449 In some cases, it is possible to take a short-cut for tuning
1450 graphical objects. For objects that are created directly from
1451 an item in the input file, you can use the @code{\tweak} command.
1454 @lilypond[relative=2,verbatim]
1459 \tweak #'duration-log #1
1462 -\tweak #'padding #8
1466 @cindex chord, modifying one note in
1468 But the main use of the @code{\tweak} command is to modify just
1469 one of a number of notation elements which start at the same musical
1470 moment, like the notes of a chord, or tuplet brackets which start
1473 For an introduction to the syntax and uses of the tweak command
1474 see @rlearning{Tweaking methods}.
1476 The @code{\tweak} command sets a property in the following object
1477 directly, without requiring the grob name or context to be
1478 specified. For this to work, it is necessary for the @code{\tweak}
1479 command to remain immediately adjacent to the object to which it is
1480 to apply after the input file has been converted to a music stream.
1481 This is often not the case, as many additional elements are inserted
1482 into the music stream implicitly. For example, when a note which is
1483 not part of a chord is processed, Lilypond implicitly inserts a
1484 @code{ChordEvent} event before the note, so separating the tweak
1485 from the note. However, if chord symbols are placed round the
1486 tweak and the note, the @code{\tweak} command comes after the
1487 @code{ChordEvent} in the music stream, so remaining adjacent to the
1488 note, and able to modify it.
1492 @lilypond[relative=2,verbatim,quote]
1493 <\tweak #'color #red c>4
1499 @lilypond[relative=2,verbatim,quote]
1500 \tweak #'color #red c4
1503 When several similar items are placed at the same musical moment,
1504 the @code{\override} command cannot be used to modify just one of
1505 them -- this is where the @code{\tweak} command must be used.
1506 Items which may appear more than once at the same musical moment
1507 include the following:
1509 @c TODO expand to include any further uses of \tweak
1511 @item note heads of notes inside a chord
1512 @item articulation signs on a single note
1513 @item ties between notes in a chord
1514 @item tuplet brackets starting at the same time
1517 @c TODO add examples of these
1520 and @code{\tweak} may be used to modify any single occurrence of
1523 Notably the @code{\tweak} command cannot be used to modify stems,
1524 beams or accidentals, since these are generated later by note heads,
1525 rather than by music elements in the input stream. Nor can a
1526 @code{\tweak} command be used to modify clefs or time signatures,
1527 since these become separated from any preceding @code{\tweak}
1528 command in the input stream by the automatic insertion of extra
1529 elements required to specify the context.
1531 But the @code{\tweak} command can be used as an alternative to
1532 the @code{\override} command to modify those notational elements
1533 that do not cause any additional implicit elements to be added
1534 before them in the music stream. For example, slurs may be
1535 modified in this way:
1537 @lilypond[verbatim,quote,relative=1]
1538 c-\tweak #'thickness #5 ( d e f)
1541 Also several @code{\tweak} commands may be placed before a
1542 notational element -- all affect it:
1544 @lilypond[verbatim,quote,relative=1]
1546 -\tweak #'style #'dashed-line
1547 -\tweak #'dash-fraction #0.2
1548 -\tweak #'thickness #3
1549 -\tweak #'color #red
1554 The music stream which is generated from a section of an input file,
1555 including any automatically inserted elements, may be examined,
1556 see @ref{Displaying music expressions}. This may be helpful in
1557 determining what may be modified by a @code{\tweak} command.
1562 @rlearning{Tweaking methods}.
1565 @ref{Displaying music expressions}.
1570 @cindex tweaks in a variable
1571 The @code{\tweak} command cannot be used inside a variable.
1573 @cindex tweaks in lyrics
1574 The @code{\tweak} commands cannot be used in @code{\lyricmode}.
1576 @cindex tweaking control points
1577 @cindex control points, tweaking
1579 The @code{\tweak} command cannot be used to modify the control
1580 points of just one of several ties in a chord, other than the first
1581 one encountered in the input file.
1583 @node set versus override
1584 @subsection @code{\set} vs. @code{\override}
1586 We have seen two methods of changing properties: @code{\set} and
1587 @code{\override}. There are actually two different kinds of
1590 Contexts can have properties, which are usually named in
1591 @code{studlyCaps}. They mostly control the translation from
1592 music to notation, eg. @code{localKeySignature} (for determining
1593 whether to print accidentals), @code{measurePosition} (for
1594 determining when to print a bar line). Context properties can
1595 change value over time while interpreting a piece of music;
1596 @code{measurePosition} is an obvious example of
1597 this. Context properties are modified with @code{\set}.
1599 There is a special type of context property: the element
1600 description. These properties are named in @code{StudlyCaps}
1601 (starting with capital letters). They contain the
1602 @q{default settings} for said graphical object as an
1603 association list. See @file{scm/@/define@/-grobs@/.scm}
1604 to see what kind of settings there are. Element descriptions
1605 may be modified with @code{\override}.
1607 @code{\override} is actually a shorthand;
1610 \override @var{context}.@var{name} #'@var{property} = #@var{value}
1614 is more or less equivalent to
1616 @c leave this long line -gp
1618 \set @var{context}.@var{name} #'@var{property} = #(cons (cons '@var{property} @var{value}) <previous value of @var{context})
1621 The value of @code{context} (the alist) is used to initialize
1622 the properties of individual grobs. Grobs also have
1623 properties, named in Scheme style, with
1624 @code{dashed-words}. The values of grob properties change
1625 during the formatting process: formatting basically amounts
1626 to computing properties using callback functions.
1628 @code{fontSize} is a special property: it is equivalent to
1629 entering @code{\override ... #'font-size} for all pertinent
1630 objects. Since this is a common change, the special
1631 property (modified with @code{\set}) was created.
1634 @node Useful concepts and properties
1635 @section Useful concepts and properties
1640 * Direction and placement::
1641 * Distances and measurements::
1642 * Staff symbol properties::
1644 * Visibility of objects::
1646 * Rotating objects::
1650 @subsection Input modes
1652 The way in which the notation contained within an input file is
1653 interpreted is determined by the current input mode.
1657 This is activated with the @code{\chordmode} command, and causes
1658 input to be interpreted with the syntax of chord notation, see
1659 @ref{Chord notation}. Chords are rendered as notes on a staff.
1661 Chord mode is also activated with the @code{\chords} command.
1662 This also creates a new @code{ChordNames} context and
1663 causes the following input to be interpreted with the syntax of
1664 chord notation and rendered as chord names in the @code{ChordNames}
1665 context, see @ref{Printing chord names}.
1669 This is activated with the @code{\drummode} command, and causes
1670 input to be interpreted with the syntax of drum notation, see
1671 @ref{Basic percussion notation}.
1673 Drum mode is also activated with the @code{\drums} command.
1674 This also creates a new @code{DrumStaff} context and causes the
1675 following input to be interpreted with the syntax of drum notation
1676 and rendered as drum symbols on a drum staff, see @ref{Basic
1677 percussion notation}.
1679 @strong{Figure mode}
1681 This is activated with the @code{\figuremode} command, and causes
1682 input to be interpreted with the syntax of figured bass, see
1683 @ref{Entering figured bass}.
1685 Figure mode is also activated with the @code{\figures} command.
1686 This also creates a new @code{FiguredBass} context and causes the
1687 following input to be interpreted with the figured bass syntax
1688 and rendered as figured bass symbols in the @code{FiguredBass}
1689 context, see @ref{Introduction to figured bass}.
1691 @strong{Fret and tab modes}
1693 There are no special input modes for entering fret and tab symbols.
1695 To create tab diagrams, enter notes or chords in note mode and
1696 render them in a @code{TabStaff} context, see
1697 @ref{Default tablatures}.
1699 To create fret diagrams above a staff, you have two choices.
1700 You can either use the @code{FretBoards} context (see
1701 @ref{Automatic fret diagrams} or you can enter them as a markup
1702 above the notes using the @code{\fret-diagram} command (see
1703 @ref{Fret diagram markups}).
1705 @strong{Lyrics mode}
1707 This is activated with the @code{\lyricmode} command, and causes
1708 input to be interpreted as lyric syllables with optional durations
1709 and associated lyric modifiers, see @ref{Vocal music}.
1711 Lyric mode is also activated with the @code{\addlyrics} command.
1712 This also creates a new @code{Lyrics} context and an implicit
1713 @code{\lyricsto} command which associates the following lyrics
1714 with the preceding music.
1716 @strong{Markup mode}
1718 This is activated with the @code{\markup} command, and causes
1719 input to be interpreted with the syntax of markup, see
1720 @ref{Text markup commands}.
1722 @c silly work-around for texinfo broken-ness
1723 @c (@strong{Note...} causes a spurious cross-reference in Info)
1726 This is the default mode or it may be activated with the
1727 @code{\notemode} command. Input is interpreted as pitches,
1728 durations, markup, etc and typeset as musical notation on a staff.
1730 It is not normally necessary to specify note mode explicitly, but
1731 it may be useful to do so in certain situations, for example if you
1732 are in lyric mode, chord mode or any other mode and want to insert
1733 something that only can be done with note mode syntax.
1735 For example, to indicate dynamic markings for the verses of a
1736 choral pieces it is necessary to enter note mode to interpret
1739 @lilypond[verbatim,relative=2,quote]
1742 \notemode{\set stanza = \markup{ \dynamic f 1. } }
1746 \notemode{\set stanza = \markup{ \dynamic p 2. } }
1753 @node Direction and placement
1754 @subsection Direction and placement
1756 In typesetting music the direction and placement of many items is
1757 a matter of choice. For example, the stems of notes can
1758 be directed up or down; lyrics, dynamics, and other expressive
1759 marks may be placed above or below the staff; text may be aligned
1760 left, right or center; etc. Most of these choices may be left to
1761 be determined automatically by LilyPond, but in some cases it may
1762 be desirable to force a particular direction or placement.
1764 @strong{Default actions}
1766 By default some directions are always up or always down (e.g.
1767 dynamics or fermata), while other things can alternate between
1768 up or down based on the stem direction (like slurs or accents).
1770 @c TODO Add table showing these
1772 @strong{Context layout order}
1774 Contexts are normally positioned in a system from top to bottom
1775 in the order in which they are encountered. Note, however, that
1776 a context will be created implicitly if a command is encountered
1777 when there is no suitable context available to contain it. When
1778 contexts are nested, the outer context will exclude inner contexts
1779 which are not included in its @qq{accepts} list; excluded contexts
1780 will be repositioned below the outer context.
1782 The default order in which contexts are laid out and the
1783 @qq{accepts} list can be changed, see @ref{Aligning contexts}.
1785 @strong{Articulation direction indicators}
1787 When adding articulations to notes the direction indicator,
1788 @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down}) or
1789 @code{-} (meaning @qq{use default direction}), can usually be
1790 omitted, in which case @code{-} is assumed. But a direction
1791 indicator is @strong{always} required before
1794 @item @code{\tweak} commands
1795 @item @code{\markup} commands
1796 @item @code{\tag} commands
1797 @item string markups, e.g. -"string"
1798 @item fingering instructions, e.g. @code{-1}
1799 @item articulation shortcuts, e.g. @code{-.}, @code{->}, @code{--}
1802 @strong{The direction property}
1804 The position or direction of many layout objects is controlled
1805 by the @code{direction} property.
1807 The value of the @code{direction} property may be
1808 set to @code{1}, meaning @qq{up} or @qq{above}, or to @code{-1},
1809 meaning @qq{down} or @qq{below}. The symbols @code{UP} and
1810 @code{DOWN} may be used instead of @code{1} and @code{-1}
1811 respectively. The default direction may be specified by setting
1812 @code{direction} to @code{0} or @code{CENTER}. Alternatively,
1813 in many cases predefined commands
1814 exist to specify the direction. These are all of the form
1817 @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral}
1820 where @code{xxxNeutral} means @qq{use the default direction}.
1821 See @rlearning{Within-staff objects}.
1823 In a few cases, arpeggio being the only common example, the value
1824 of the @code{direction} property specifies whether the object
1825 is to be placed to the right or left of the parent object. In
1826 this case @code{-1} or @code{LEFT} means @qq{to the left} and
1827 @code{1} or @code{RIGHT} means @qq{to the right}. @code{0}
1828 or @code{CENTER} means @qq{use the default} direction, as before.
1831 These all have side-axis set to #X
1832 AmbitusAccidental - direction has no effect
1834 StanzaNumber - not tried
1835 TrillPitchAccidental - not tried
1836 TrillPitchGroup - not tried
1841 @node Distances and measurements
1842 @subsection Distances and measurements
1844 @cindex distances, absolute
1845 @cindex distances, scaled
1852 Distances in LilyPond are of two types: absolute and scaled.
1854 Absolute distances are used for specifying margins, indents, and
1855 other page layout details, and are by default specified in
1856 millimeters. Distances may be specified in other units by
1857 following the quantity by @code{\mm}, @code{\cm},
1858 @code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27
1859 of an inch). Page layout distances can also be specified in
1860 scalable units (see the following paragraph) by appending
1861 @code{\staff-space} to the quantity.
1862 Page layout is described in detail in @ref{Page formatting}.
1864 Scaled distances are always specified in units of the staff-space
1865 or, rarely, the half staff-space. The staff-space is the distance
1866 between two adjacent staff lines. The default value can be changed
1867 globally by setting the global staff size, or it can be overridden
1868 locally by changing the @code{staff-space} property of
1869 @code{StaffSymbol}. Scaled distances automatically scale with any
1870 change to the either the global staff size or the
1871 @code{staff-space} property of @code{StaffSymbol}, but fonts scale
1872 automatically only with changes to the global staff size.
1873 The global staff size thus enables the overall size of a rendered
1874 score to be easily varied. For the methods of setting the global
1875 staff size see @ref{Setting the staff size}.
1879 If just a section of a score needs to be rendered to a different
1880 scale, for example an ossia section or a footnote, the global staff
1881 size cannot simply be changed as this would affect the entire score.
1882 In such cases the change in size is made by overriding both the
1883 @code{staff-space} property of @code{StaffSymbol} and the size of
1884 the fonts. A Scheme function, @code{magstep}, is available to
1885 convert from a font size change to the equivalent change in
1886 @code{staff-space}. For an explanation and an example of its use,
1887 see @rlearning{Length and thickness of objects}.
1892 @rlearning{Length and thickness of objects}.
1895 @ref{Page formatting},
1896 @ref{Setting the staff size}.
1899 @node Staff symbol properties
1900 @subsection Staff symbol properties
1902 @cindex adjusting staff symbol
1903 @cindex drawing staff symbol
1904 @cindex staff symbol, setting of
1906 @c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
1907 @c Need to think of uses for these properties. Eg 'line-positions
1908 @c is used in a snippet to thicken centre line.
1909 @c If retained, add @ref to here in 1.6.2 -td
1911 The vertical position of staff lines and the number of staff lines
1912 can be defined at the same time. As the following example shows,
1913 note positions are not influenced by the staff line positions.
1915 @warning{The @code{'line-positions} property overrides the
1916 @code{'line-count} property. The number of staff lines is
1917 implicitly defined by the number of elements in the list of values
1918 for @code{'line-positions}.}
1920 @lilypond[verbatim,quote,relative=1]
1922 \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
1927 The width of a staff can be modified. The units are staff
1928 spaces. The spacing of objects inside the staff is not affected by
1931 @lilypond[verbatim,quote,relative=1]
1933 \override StaffSymbol #'width = #23
1940 @subsection Spanners
1942 Many objects of musical notation extend over several notes or even
1943 several bars. Examples are slurs, beams, tuplet brackets, volta
1944 repeat brackets, crescendi, trills, and glissandi. Such objects
1945 are collectively called @qq{spanners}, and have special properties to control
1946 their appearance and behaviour. Some of these properties are common
1947 to all spanners; others are restricted to a sub-set of the spanners.
1949 All spanners support the @code{spanner-interface}. A few, esentially
1950 those that draw a straight line between the two objects, support in
1951 addition the @code{line-spanner-interface}.
1953 @unnumberedsubsubsec Using the @code{spanner-interface}
1955 This interface provides two properties that apply to several spanners.
1957 @strong{@i{The @code{minimum-length} property}}
1959 The minimum length of the spanner is specified by the
1960 @code{minimum-length} property. Increasing this usually has the
1961 necessary effect of increasing the spacing of the notes between the
1962 two end points. However, this override has no effect on
1963 many spanners, as their length is determined by other considerations.
1964 A few examples where it is effective are shown below.
1974 Works as long as callback is made:
1978 Works not at all for:
1987 @lilypond[verbatim,quote,relative=2]
1990 % increase the length of the tie
1991 -\tweak #'minimum-length #5
1995 @lilypond[verbatim,quote,relative=2]
1997 \compressFullBarRests
1999 % increase the length of the rest bar
2000 \once \override MultiMeasureRest #'minimum-length = #20
2005 @lilypond[verbatim,quote,relative=2]
2007 % increase the length of the hairpin
2008 \override Hairpin #'minimum-length = #20
2012 This override can also be used to increase the length of slurs and
2015 @lilypond[verbatim,quote,relative=2]
2018 -\tweak #'minimum-length #5
2023 -\tweak #'minimum-length #5
2027 For some layout objects, the @code{minimum-length} property becomes
2028 effective only if the @code{set-spacing-rods} procedure is called
2029 explicitly. To do this, the @code{springs-and-rods} property should
2030 be set to @code{ly:spanner::set-spacing-rods}. For example,
2031 the minimum length of a glissando has no effect unless the
2032 @code{springs-and-rods} property is set:
2034 @lilypond[verbatim,quote,relative=1]
2038 % not effective alone
2039 \once \override Glissando #'minimum-length = #20
2042 % effective only when both overrides are present
2043 \once \override Glissando #'minimum-length = #20
2044 \once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
2048 The same is true of the @code{Beam} object:
2050 @lilypond[verbatim,quote,relative=1]
2051 % not effective alone
2052 \once \override Beam #'minimum-length = #20
2055 % effective only when both overrides are present
2056 \once \override Beam #'minimum-length = #20
2057 \once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
2061 @strong{@i{The @code{to-barline} property}}
2063 The second useful property of the @code{spanner-interface} is
2064 @code{to-barline}. By default this is true, causing hairpins and
2065 other spanners which are terminated on the first note of a measure to
2066 end instead on the immediately preceding bar line. If set to false,
2067 the spanner will extend beyond the bar line and end on the note
2070 @lilypond[verbatim,quote,relative=2]
2071 a \< a a a a \! a a a \break
2072 \override Hairpin #'to-barline = ##f
2073 a \< a a a a \! a a a
2076 This property is not effective for all spanners. For example,
2077 seting it to @code{#t} has no effect on slurs or phrasing slurs
2078 or on other spanners for which terminating on the bar line would
2081 @unnumberedsubsubsec Using the @code{line-spanner-interface}
2083 Objects which support the @code{line-spanner-interface} include
2086 @item @code{DynamicTextSpanner}
2087 @item @code{Glissando}
2088 @item @code{TextSpanner}
2089 @item @code{TrillSpanner}
2090 @item @code{VoiceFollower}
2093 The routine responsible for drawing the stencils for these spanners is
2094 @code{ly:line-interface::print}. This routine determines the
2095 exact location of the two end points and draws a line
2096 between them, in the style requested. The locations of the two
2097 end points of the spanner are computed on-the-fly, but it is
2098 possible to override their Y-coordinates. The
2099 properties which need to be specified are nested
2100 two levels down within the property hierarchy, but the syntax of
2101 the @code{\override} command is quite simple:
2103 @lilypond[relative=2,quote,verbatim]
2105 \once \override Glissando #'(bound-details left Y) = #3
2106 \once \override Glissando #'(bound-details right Y) = #-2
2110 The units for the @code{Y} property are @code{staff-space}s,
2111 with the center line of the staff being the zero point.
2112 For the glissando, this is the value for @code{Y} at the
2113 X-coordinate corresponding to the center point of each note head,
2114 if the line is imagined to be extended to there.
2116 If @code{Y} is not set, the value is computed from the vertical
2117 position of the corresponding attachment point of the spanner.
2119 In case of a line break, the values for the end points are
2120 specified by the @code{left-broken} and @code{right-broken}
2121 sub-lists of @code{bound-details}. For example:
2123 @lilypond[relative=2,ragged-right,verbatim,fragment]
2124 \override Glissando #'breakable = ##t
2125 \override Glissando #'(bound-details right-broken Y) = #-3
2126 c1 \glissando \break
2131 A number of further properties of the @code{left} and
2132 @code{right} sub-lists of the @code{bound-details} property
2133 may be modified in the same way as @code{Y}:
2137 This sets the Y-coordinate of the end point, in @code{staff-space}s
2138 offset from the staff center line. By default, it is the center of
2139 the bound object, so a glissando points to the vertical center of
2142 For horizontal spanners, such as text spanners and trill spanners,
2143 it is hardcoded to 0.
2146 This determines where the line starts and ends in the X-direction,
2147 relative to the bound object. So, a value of @code{-1} (or
2148 @code{LEFT}) makes the line start/end at the left side of the note
2149 head it is attached to.
2152 This is the absolute X-coordinate of the end point. It is usually
2153 computed on the fly, and overriding it has little useful effect.
2156 Line spanners may have symbols at the beginning or end, which is
2157 contained in this sub-property. This is for internal use; it is
2158 recommended that @code{text} be used instead.
2161 This is a markup that is evaluated to yield the stencil. It is used
2162 to put @i{cresc.}, @i{tr} and other text on horizontal spanners.
2164 @lilypond[quote,ragged-right,fragment,relative=2,verbatim]
2165 \override TextSpanner #'(bound-details left text)
2166 = \markup { \small \bold Slower }
2167 c2\startTextSpan b c a\stopTextSpan
2170 @item stencil-align-dir-y
2171 @item stencil-offset
2172 Without setting one of these, the stencil is simply put at the
2173 end-point, centered on the line, as defined by the @code{X} and
2174 @code{Y} sub-properties. Setting either @code{stencil-align-dir-y}
2175 or @code{stencil-offset} will move the symbol at the edge vertically
2176 relative to the end point of the line:
2178 @lilypond[relative=1,fragment,verbatim]
2179 \override TextSpanner
2180 #'(bound-details left stencil-align-dir-y) = #-2
2181 \override TextSpanner
2182 #'(bound-details right stencil-align-dir-y) = #UP
2184 \override TextSpanner
2185 #'(bound-details left text) = #"ggg"
2186 \override TextSpanner
2187 #'(bound-details right text) = #"hhh"
2188 c4^\startTextSpan c c c \stopTextSpan
2191 Note that negative values move the text @emph{up}, contrary to the
2192 effect that might be expected, as a value of @code{-1} or
2193 @code{DOWN} means align the @emph{bottom} edge of the text with
2194 the spanner line. A value of @code{1} or @code{UP} aligns
2195 the top edge of the text with the spanner line.
2198 Setting this sub-property to @code{#t} produces an arrowhead at the
2202 This sub-property controls the space between the specified
2203 end point of the line and the actual end. Without padding, a
2204 glissando would start and end in the center of each note head.
2208 The music function @code{\endSpanners} terminates the spanner
2209 which starts on the immediately following note prematurely. It
2210 is terminated after exactly one note, or at the following bar line
2211 if @code{to-barline} is true and a bar line occurs before the next
2214 @lilypond[verbatim,quote,ragged-right,relative=2,fragment]
2216 c2 \startTextSpan c2 c2
2221 When using @code{\endSpanners} it is not necessary to close
2222 \startTextSpan with \stopTextSpan, nor is it necessary to close
2223 hairpins with @code{\!}.
2227 Internals Reference: @rinternals{TextSpanner},
2228 @rinternals{Glissando}, @rinternals{VoiceFollower},
2229 @rinternals{TrillSpanner},
2230 @rinternals{line-spanner-interface}.
2233 @node Visibility of objects
2234 @subsection Visibility of objects
2236 @cindex objects, visibility of
2237 @cindex grobs, visibility of
2238 @cindex visibility of objects
2240 There are four main ways in which the visibility of layout objects
2241 can be controlled: their stencil can be removed, they can be made
2242 transparent, they can be colored white, or their
2243 @code{break-visibility} property can be overridden. The first
2244 three apply to all layout objects; the last to just a few -- the
2245 @emph{breakable} objects. The Learning Manual introduces these
2246 four techniques, see @rlearning{Visibility and color of objects}.
2248 There are also a few other techniques which are specific to
2249 certain layout objects. These are covered under Special
2253 * Removing the stencil::
2254 * Making objects transparent::
2255 * Painting objects white::
2256 * Using break-visibility::
2257 * Special considerations::
2261 @node Removing the stencil
2262 @unnumberedsubsubsec Removing the stencil
2264 @cindex stencil, removing
2266 Every layout object has a stencil property. By default this is set
2267 to the specific function which draws that object. If this property
2268 is overridden to @code{#f} no function will be called and the object
2269 will not be drawn. The default action can be recovered with
2272 @lilypond[quote,verbatim,relative=1]
2274 \override Score.BarLine #'stencil = ##f
2276 \revert Score.BarLine #'stencil
2280 @node Making objects transparent
2281 @unnumberedsubsubsec Making objects transparent
2283 @cindex transparent, making objects
2285 Every layout object has a transparent property which by default is
2286 set to @code{#f}. If set to @code{#t} the object still occupies
2287 space but is made invisible.
2289 @lilypond[quote,verbatim,relative=2]
2291 \once \override NoteHead #'transparent = ##t
2295 @node Painting objects white
2296 @unnumberedsubsubsec Painting objects white
2298 @cindex objects, coloring
2299 @cindex coloring objects
2301 @cindex printing order
2302 @cindex overwriting objects
2303 @cindex objects, overwriting
2304 @cindex grobs, overwriting
2306 Every layout object has a color property which by default is set
2307 to @code{black}. If this is overridden to @code{white} the object
2308 will be indistinguishable from the white background. However,
2309 if the object crosses other objects the color of the crossing
2310 points will be determined by the order in which they are drawn,
2311 and this may leave a ghostly image of the white object, as shown
2314 @lilypond[quote,verbatim,relative=2]
2315 \override Staff.Clef #'color = #white
2319 This may be avoided by changing the order of printing the objects.
2320 All layout objects have a @code{layer} property which should be set
2321 to an integer. Objects with the lowest value of @code{layer} are
2322 drawn first, then objects with progressively higher values are drawn,
2323 so objects with higher values overwrite objects with lower values.
2324 By default most objects are assigned a @code{layer} value of
2325 @code{1}, although a few objects, including @code{StaffSymbol} and
2326 @code{BarLine}, are assigned a value of @code{0}. The order of
2327 printing objects with the same value of @code{layer} is indeterminate.
2329 In the example above the white clef, with a default @code{layer}
2330 value of @code{1}, is drawn after the staff lines (default
2331 @code{layer} value @code{0}), so overwriting them. To change this,
2332 the @code{Clef} object must be given in a lower value of
2333 @code{layer}, say @code{-1}, so that it is drawn earlier:
2335 @lilypond[quote,verbatim,relative=2]
2336 \override Staff.Clef #'color = #white
2337 \override Staff.Clef #'layer = #-1
2341 @node Using break-visibility
2342 @unnumberedsubsubsec Using break-visibility
2344 @c TODO Add making other objects breakable
2346 @cindex break-visibility
2348 Most layout objects are printed only once, but some like
2349 bar lines, clefs, time signatures and key signatures, may need
2350 to be printed twice when a line break occurs -- once at the end
2351 of the line and again at the start of the next line. Such
2352 objects are called @emph{breakable}, and have a property, the
2353 @code{break-visibility} property to control their visibility
2354 at the three positions in which they may appear -- at the
2355 start of a line, within a line if they are changed, and at the
2356 end of a line if a change takes place there.
2358 For example, the time signature
2359 by default will be printed at the start of the first line, but
2360 nowhere else unless it changes, when it will be printed at the
2361 point at which the change occurs. If this change occurs at the
2362 end of a line the new time signature will be printed at the start
2363 of the next line and a cautionary time signature will be printed
2364 at the end of the previous line as well.
2366 This behaviour is controlled by the @code{break-visibility}
2367 property, which is explained in
2368 @c Leave this ref on a newline - formats incorrectly otherwise -td
2369 @rlearning{Visibility and color of objects}. This property takes
2370 a vector of three booleans which, in order, determine whether the
2371 object is printed at the end of, within the body of, or at the
2372 beginning of a line. Or to be more precise, before a line break,
2373 where there is no line break, or after a line break.
2375 Alternatively, these eight combinations may be specified
2376 by pre-defined functions, defined in @file{scm/output-lib.scm},
2377 where the last three columns indicate whether the layout objects
2378 will be visible in the positions shown at the head of the columns:
2380 @multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
2381 @headitem Function @tab Vector @tab Before @tab At no @tab After
2382 @headitem form @tab form @tab break @tab break @tab break
2384 @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
2385 @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
2386 @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
2387 @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no
2388 @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no
2389 @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes
2390 @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
2391 @item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
2394 The default settings of @code{break-visibility} depend on the
2395 layout object. The following table shows all the layout objects
2396 of interest which are affected by @code{break-visibility} and the
2397 default setting of this property:
2399 @multitable @columnfractions .3 .3 .4
2401 @headitem Layout object @tab Usual context @tab Default setting
2403 @c omit Ambitus as it appears not to be affected by break-visibility -td
2404 @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible}
2405 @item @code{BarLine} @tab @code{Score} @tab calculated
2406 @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible}
2407 @c omit the following item until it can be explained -td
2408 @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated
2409 @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2410 @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible}
2411 @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible}
2412 @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible}
2413 @c omit KeyCancellation until it can be explained -td
2414 @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible}
2415 @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible}
2416 @c omit LeftEdge until it can be explained -td
2417 @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible}
2418 @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible}
2419 @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible}
2420 @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible}
2424 The example below shows the use of the vector form to control the
2425 visibility of barlines:
2427 @lilypond[quote,verbatim,relative=1,ragged-right]
2430 % Remove bar line at the end of the current line
2431 \once \override Score.BarLine #'break-visibility = #'#(#f #t #t)
2437 Although all three components of the vector used to override
2438 @code{break-visibility} must be present, not all of them are
2439 effective with every layout object, and some combinations may
2440 even give errors. The following limitations apply:
2443 @item Bar lines cannot be printed at start of line.
2444 @item A bar number cannot be printed at the start of the first
2445 line unless it is set to be different from 1.
2446 @item Clef -- see below
2447 @item Double percent repeats are either all printed or all
2448 suppressed. Use begin-of line-invisible to print and
2449 all-invisible to suppress.
2450 @item Key signature -- see below
2451 @item OctavateEight -- see below
2454 @node Special considerations
2455 @unnumberedsubsubsec Special considerations
2457 @strong{@emph{Visibility following explicit changes}}
2459 @cindex key signature, visibility following explicit change
2460 @cindex explicitKeySignatureVisibility
2461 @cindex clef, visibility following explicit change
2462 @cindex explicitClefVisibility
2464 The @code{break-visibility} property controls the visibility of
2465 key signatures and changes of clef only at the start of lines,
2466 i.e. after a break. It has no effect on the visibility of the
2467 key signature or clef following an explicit key change or an
2468 explicit clef change within or at the end of a line. In the
2469 following example the key signature following the explicit change
2470 to B-flat major is still visible, even though @code{all-invisible}
2473 @lilypond[quote,verbatim,relative=1,ragged-right]
2476 % Try to remove all key signatures
2477 \override Staff.KeySignature #'break-visibility = #all-invisible
2485 The visibility of such explicit key signature and clef changes is
2486 controlled by the @code{explicitKeySignatureVisibility} and
2487 @code{explicitClefVisibility} properties. These are the equivalent
2488 of the @code{break-visibility} property and both take a vector of
2489 three booleans or the predefined functions listed above, exactly like
2490 @code{break-visibility}. Both are properties of the Staff context,
2491 not the layout objects themselves, and so they are set using the
2492 @code{\set} command. Both are set by default to @code{all-visible}.
2493 These properties control only the visibility of key signatures and
2494 clefs resulting from explicit changes and do not affect key
2495 signatures and clefs at the beginning of lines;
2496 @code{break-visibility} must still be overridden in the appropriate
2497 object to remove these.
2499 @lilypond[quote,verbatim,relative=1,ragged-right]
2502 \set Staff.explicitKeySignatureVisibility = #all-invisible
2503 \override Staff.KeySignature #'break-visibility = #all-invisible
2510 @strong{@emph{Visibility of cautionary accidentals}}
2512 To remove the cautionary accidentals printed at an explicit key
2513 change, set the Staff context property @code{printKeyCancellation}
2516 @lilypond[quote,verbatim,relative=1,ragged-right]
2519 \set Staff.explicitKeySignatureVisibility = #all-invisible
2520 \set Staff.printKeyCancellation = ##f
2521 \override Staff.KeySignature #'break-visibility = #all-invisible
2528 With these overrides only the accidentals before the notes remain
2529 to indicate the change of key.
2531 @c TODO Add visibility of cautionary accidentals before notes
2533 @strong{@emph{Automatic bars}}
2535 @cindex automaticBars
2536 @cindex bar lines, suppressing
2538 As a special case, the printing of bar lines can also be turned off
2539 by setting the @code{automaticBars} property in the Score context.
2540 If set to @code{#f}, bar lines will not be printed automatically;
2541 they must be explicitly created with a @code{\bar} command. Unlike
2542 the @code{\cadenzaOn} predefined command, measures are still counted.
2543 Bar generation will resume according to that count if this property
2544 is later set to @code{#t}. When set to @code{#f}, line breaks can
2545 occur only at explicit @code{\bar} commands.
2549 @strong{@emph{Octavated clefs}}
2551 @cindex octavated clefs, visibility of
2552 @cindex visibility of octavated clefs
2553 @cindex clefs, visibility of octavation
2555 The small octavation symbol on octavated clefs is produced by the
2556 @code{OctavateEight} layout object. Its visibility is controlled
2557 independently from that of the @code{Clef} object, so it is
2558 necessary to apply any required @code{break-visibility} overrides
2559 to both the @code{Clef} and the @code{OctavateEight} layout objects
2560 to fully suppress such clef symbols at the start of each line.
2562 For explicit clef changes, the @code{explicitClefVisibility}
2563 property controls both the clef symbol and any octavation symbol
2569 @rlearning{Visibility and color of objects}
2573 @subsection Line styles
2575 Some performance indications, e.g., @i{rallentando} and
2576 @i{accelerando} and @i{trills} are written as text and are
2577 extended over many measures with lines, sometimes dotted or wavy.
2579 These all use the same routines as the glissando for drawing the
2580 texts and the lines, and tuning their behavior is therefore also
2581 done in the same way. It is done with a spanner, and the routine
2582 responsible for drawing the spanners is
2583 @code{ly:line-interface::print}. This routine determines the
2584 exact location of the two @i{span points} and draws a line
2585 between them, in the style requested.
2587 Here is an example showing the different line styles available,
2588 and how to tune them.
2590 @lilypond[relative=2,ragged-right,verbatim,fragment]
2592 \once \override Glissando #'style = #'dashed-line
2594 \override Glissando #'style = #'dotted-line
2596 \override Glissando #'style = #'zigzag
2598 \override Glissando #'style = #'trill
2602 The locations of the end-points of the spanner are computed
2603 on-the-fly for every graphic object, but it is possible to
2607 @lilypond[relative=2,ragged-right,verbatim,fragment]
2609 \once \override Glissando #'(bound-details right Y) = #-2
2613 The value for @code{Y} is set to @code{-2} for the right end
2614 point. The left side may be similarly adjusted by specifying
2615 @code{left} instead of @code{right}.
2617 If @code{Y} is not set, the value is computed from the vertical
2618 position of the left and right attachment points of the spanner.
2620 Other adjustments of spanners are possible, for details, see
2623 @node Rotating objects
2624 @subsection Rotating objects
2626 Both layout objects and elements of markup text can be rotated by
2627 any angle about any point, but the method of doing so differs.
2630 * Rotating layout objects::
2634 @node Rotating layout objects
2635 @unnumberedsubsubsec Rotating layout objects
2637 @cindex rotating objects
2638 @cindex objects, rotating
2640 All layout objects which support the @code{grob-interface} can be
2641 rotated by setting their @code{rotation} property. This takes a
2642 list of three items: the angle of rotation counter-clockwise,
2643 and the x and y coordinates of the point relative to the object's
2644 reference point about which the rotation is to be performed. The
2645 angle of rotation is specified in degrees and the coordinates in
2648 The angle of rotation and the coordinates of the rotation point must
2649 be determined by trial and error.
2651 @cindex hairpins, angled
2652 @cindex angled hairpins
2654 There are only a few situations where the rotation of layout
2655 objects is useful; the following example shows one situation where
2658 @lilypond[quote,verbatim,relative=1]
2660 \override Hairpin #'rotation = #'(20 -1 0)
2664 @node Rotating markup
2665 @unnumberedsubsubsec Rotating markup
2667 All markup text can be rotated to lie at any angle by prefixing it
2668 with the @code{\rotate} command. The command takes two arguments:
2669 the angle of rotation in degrees counter-clockwise and the text to
2670 be rotated. The extents of the text are not rotated: they take
2671 their values from the extremes of the x and y coordinates of the
2672 rotated text. In the following example the
2673 @code{outside-staff-priority} property for text is set to @code{#f}
2674 to disable the automatic collision avoidance, which would push some
2675 of the text too high.
2677 @lilypond[quote,verbatim,relative=1]
2678 \override TextScript #'outside-staff-priority = ##f
2679 g4^\markup { \rotate #30 "a G" }
2680 b^\markup { \rotate #30 "a B" }
2681 des^\markup { \rotate #30 "a D-Flat" }
2682 fis^\markup { \rotate #30 "an F-Sharp" }
2685 @node Advanced tweaks
2686 @section Advanced tweaks
2688 This section discusses various approaches to fine tuning the
2689 appearance of the printed score.
2692 * Aligning objects::
2693 * Vertical grouping of grobs::
2694 * Modifying stencils::
2695 * Modifying shapes::
2701 @rlearning{Tweaking output},
2702 @rlearning{Other sources of information}.
2705 @ref{Explaining the Internals Reference},
2706 @ref{Modifying properties},
2707 @ref{Interfaces for programmers}.
2710 @file{scm/@/define@/-grobs@/.scm}.
2713 @rlsr{Tweaks and overrides}.
2715 Internals Reference:
2716 @rinternals{All layout objects}.
2719 @node Aligning objects
2720 @subsection Aligning objects
2722 Graphical objects which support the @code{self-alignment-interface} and/or
2723 the @code{side-position-interface} can be
2724 aligned to a previously placed object in a variety of ways. For a list of these objects, see
2725 @rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
2727 All graphical objects have a reference point, a horizontal extent and a
2728 vertical extent. The horizontal extent is a pair of numbers
2729 giving the displacements from the reference point of the left and
2730 right edges, displacements to the left being negative. The
2731 vertical extent is a pair of numbers giving the displacement from
2732 the reference point to the bottom and top edges, displacements down
2735 An object's position on a staff is given by the values of the
2736 @code{X-offset} and @code{Y-offset} properties. The value of
2737 @code{X-offset} gives the displacement from the x coordinate of
2738 the reference point of the parent object, and the value of
2739 @code{Y-offset} gives the displacement from the center line of the
2740 staff. The values of @code{X-offset} and
2741 @code{Y-offset} may be set directly or may be set to be calculated
2742 by procedures in order to achieve alignment with the parent object
2745 @warning{Many objects have special positioning considerations which
2746 cause any setting of @code{X-offset} or @code{Y-offset} to be
2747 ignored or modified, even though the object supports the
2748 @code{self-alignment-interface}.}
2750 For example, an accidental can be repositioned
2751 vertically by setting @code{Y-offset} but any changes to
2752 @code{X-offset} have no effect.
2754 Rehearsal marks may be aligned with
2755 breakable objects such as bar lines, clef symbols, time signature
2756 symbols and key signatures. There are special properties to be
2757 found in the @code{break-aligned-interface} for positioning rehearsal
2758 marks on such objects.
2761 * Setting @code{X-offset} and @code{Y-offset} directly::
2762 * Using the @code{side-position-interface}::
2763 * Using the @code{self-alignment-interface}::
2764 * Using the @code{break-aligned-interface}::
2767 @node Setting @code{X-offset} and @code{Y-offset} directly
2768 @unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
2770 Numerical values may be given to the @code{X-offset} and @code{Y-offset}
2771 properties of many objects. The following example shows three
2772 notes with the default fingering position and the positions with @code{X-offset}
2773 and @code{Y-offset} modified.
2775 @lilypond[verbatim,quote,relative=2]
2778 -\tweak #'X-offset #0
2779 -\tweak #'Y-offset #0
2782 -\tweak #'X-offset #-1
2783 -\tweak #'Y-offset #1
2789 @node Using the @code{side-position-interface}
2790 @unnumberedsubsubsec Using the @code{side-position-interface}
2792 An object which supports the @code{side-position-interface} can be
2793 placed next to its parent object so that
2794 the specified edges of the two objects touch. The object may be
2795 placed above, below, to the right or to the left of the parent.
2796 The parent cannot be specified; it is determined by the order of
2797 elements in the input stream. Most objects have the associated
2798 note head as their parent.
2800 The values of the @code{side-axis} and @code{direction} properties
2801 determine where the object is to be placed, as follows:
2803 @c TODO add an example of each to the table
2805 @multitable @columnfractions .3 .3 .3
2806 @headitem @code{side-axis} @tab @code{direction} @tab
2807 @headitem property @tab property @tab Placement
2809 @item @code{0} @tab @code{-1} @tab left
2810 @item @code{0} @tab @code{1} @tab right
2811 @item @code{1} @tab @code{-1} @tab below
2812 @item @code{1} @tab @code{1} @tab above
2816 When @code{side-axis} is @code{0}, @code{X-offset} should be set to
2817 the procedure @code{ly:side-position-interface::x-aligned-side}.
2818 This procedure will return the correct value of @code{X-offset} to
2819 place the object to the left or right side of the parent according
2820 to value of @code{direction}.
2822 When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
2823 the procedure @code{ly:side-position-interface::y-aligned-side}.
2824 This procedure will return the correct value of @code{Y-offset} to
2825 place the object to the top or bottom of the parent according
2826 to value of @code{direction}.
2828 @c TODO Add examples
2830 @node Using the @code{self-alignment-interface}
2831 @unnumberedsubsubsec Using the @code{self-alignment-interface}
2833 @emph{Self-aligning objects horizontally}
2835 The horizontal alignment of an object which supports the
2836 @code{self-alignment-interface} is controlled by the value of
2837 the @code{self-alignment-X} property, provided the object's
2838 @code{X-offset} property is set to
2839 @code{ly:self-alignment-interface::x-aligned-on-self}.
2840 @code{self-alignment-X} may be given any
2841 real value, in units of half the total X extent of the
2842 object. Negative values move the object to the right, positive
2843 to the left. A value of @code{0} centers the object on the
2844 reference point of its parent, a value of @code{-1} aligns the
2845 left edge of the object on the reference point of its parent,
2846 and a value of @code{1} aligns the right edge of the object on the
2847 reference point of its parent. The symbols @code{LEFT},
2848 @code{CENTER} and @code{RIGHT} may be used instead of the values
2849 @code{-1, 0, 1} respectively.
2851 Normally the @code{\override} command would be used to modify the
2852 value of @code{self-alignment-X}, but the @code{\tweak} command
2853 can be used to separately align several annotations on a single
2856 @lilypond[quote,verbatim,relative=1]
2858 -\tweak #'self-alignment-X #-1
2860 -\tweak #'self-alignment-X #0
2862 -\tweak #'self-alignment-X #RIGHT
2864 -\tweak #'self-alignment-X #-2.5
2865 ^"aligned further to the right"
2868 @emph{Self-aligning objects vertically}
2870 Objects may be aligned vertically in an analogous way to aligning
2871 them horizontally if the @code{Y-offset} property is set to
2872 @code{ly:self-alignment-interface::y-aligned-on-self}. However,
2873 other mechanisms are often involved in vertical alignment: the
2874 value of @code{Y-offset} is just one variable taken into account.
2875 This may make adjusting the value of some objects tricky.
2876 The units are just half the vertical extent of the object, which
2877 is usually quite small, so quite large numbers may be required.
2878 A value of @code{-1} aligns the lower edge of the object with
2879 the reference point of the parent object, a value of @code{0}
2880 aligns the center of the object with the reference point of the
2881 parent, and a value of @code{1} aligns the top edge of the object
2882 with the reference point of the parent. The symbols @code{DOWN},
2883 @code{CENTER}, @code{UP} may be substituted for @code{-1, 0, 1}
2886 @emph{Self-aligning objects in both directions}
2888 By setting both @code{X-offset} and @code{Y-offset}, an object may
2889 be aligned in both directions simultaneously.
2891 The following example shows how to adjust a fingering mark so
2892 that it nestles close to the note head.
2894 @lilypond[quote,verbatim,relative=2]
2896 -\tweak #'self-alignment-X #0.5 % move horizontally left
2897 -\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
2898 -\tweak #'self-alignment-Y #-1 % move vertically up
2903 @unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
2905 @c Cannot document as they do not seem to operate consistently on all objects -td
2906 @c TODO investigate further
2908 The @code{aligned-on-parent} procedures are used in the same way
2909 as the @code{aligned-on-self} procedures, they difference being
2910 that they permit an object to be aligned with the @emph{edges} of
2911 the parent rather than the parent's reference point. The following
2912 example shows the difference:
2916 @lilypond[verbatim,quote]
2922 @unnumberedsubsubsec Using the @code{centered-on-parent} procedures
2924 @c Cannot document as they do not seem to operate consistently on all objects -td
2925 @c TODO investigate further
2929 @c TODO The align-interface, BassFigureAlignment and VerticalAlignment
2931 @node Using the @code{break-aligned-interface}
2932 @unnumberedsubsubsec Using the @code{break-aligned-interface}
2934 Rehearsal marks may be aligned with notation objects other
2935 than bar lines. These objects include @code{ambitus},
2936 @code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
2937 @code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
2938 @code{time-signature}.
2940 By default, rehearsal marks will be horizontally centered above the
2943 @lilypond[verbatim,quote,relative=1]
2945 % the RehearsalMark will be centered above the Clef
2946 \override Score.RehearsalMark #'break-align-symbols = #'(clef)
2951 % the RehearsalMark will be centered above the TimeSignature
2952 \override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
2960 The alignment of the rehearsal mark relative to the notation object
2961 can be changed, as shown in the following example. In a score with
2962 multiple staves, this setting should be done for all the staves.
2964 @lilypond[verbatim,quote,relative=1]
2965 % The RehearsalMark will be centered above the KeySignature
2966 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
2972 % The RehearsalMark will be aligned with the left edge of the KeySignature
2973 \once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
2977 % The RehearsalMark will be aligned with the right edge of the KeySignature
2978 \once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
2984 The rehearsal mark can also be offset to the right or left of the left edge
2985 by an arbitrary amount. The units are staff-spaces:
2987 @lilypond[verbatim,quote,relative=1]
2988 % The RehearsalMark will be aligned with the left edge of the KeySignature
2989 % and then shifted right by 3.5 staff-spaces
2990 \override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
2991 \once \override Score.KeySignature #'break-align-anchor = #3.5
2995 % The RehearsalMark will be aligned with the left edge of the KeySignature
2996 % and then shifted left by 2 staff-spaces
2997 \once \override Score.KeySignature #'break-align-anchor = #-2
3005 @node Vertical grouping of grobs
3006 @subsection Vertical grouping of grobs
3008 @c FIXME Expand this section
3010 The VerticalAlignment and VerticalAxisGroup grobs work together.
3011 VerticalAxisGroup groups together different grobs like Staff, Lyrics,
3012 etc. VerticalAlignment then vertically aligns the different grobs
3013 grouped together by VerticalAxisGroup. There is usually only one
3014 VerticalAlignment per score but every Staff, Lyrics, etc. has its own
3018 @node Modifying stencils
3019 @subsection Modifying stencils
3021 All layout objects have a @code{stencil} property which is part of
3022 the @code{grob-interface}. By default, this property is usually
3023 set to a function specific to the object that is tailor-made to
3024 render the symbol which represents it in the output. For example,
3025 the standard setting for the @code{stencil} property of the
3026 @code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
3028 The standard symbol for any object can be replaced by modifying the
3029 @code{stencil} property to reference a different, specially-written,
3030 procedure. This requires a high level of knowledge of the internal
3031 workings of LilyPond, but there is an easier way which can often
3032 produce adequate results.
3034 This is to set the @code{stencil} property to the procedure which
3035 prints text -- @code{ly:text-interface::print} -- and to add a
3036 @code{text} property to the object which is set to contain the
3037 markup text which produces the required symbol. Due to the
3038 flexibility of markup, much can be achieved -- see in particular
3039 @ref{Graphic notation inside markup}.
3041 The following example demonstrates this by changing the note head
3042 symbol to a cross within a circle.
3044 @lilypond[verbatim,quote]
3046 \once \override NoteHead #'stencil = #ly:text-interface::print
3047 \once \override NoteHead #'text = \markup {
3049 \halign #-0.7 \draw-circle #0.85 #0.2 ##f
3050 \musicglyph #"noteheads.s2cross"
3058 Any of the glyphs in the feta Font can be supplied to the
3059 @code{\musicglyph} markup command -- see @ref{The Feta font}.
3061 @c TODO Add inserting eps files or ref to later
3063 @c TODO Add inserting Postscript or ref to later
3068 @ref{Graphic notation inside markup},
3069 @ref{Formatting text},
3070 @ref{Text markup commands},
3071 @ref{The Feta font}.
3074 @node Modifying shapes
3075 @subsection Modifying shapes
3078 * Modifying ties and slurs::
3081 @node Modifying ties and slurs
3082 @unnumberedsubsubsec Modifying ties and slurs
3084 Ties, slurs and phrasing slurs are drawn as third-order Bézier
3085 curves. If the shape of the tie or slur which is calculated
3086 automatically is not optimum, the shape may be modified manually by
3087 explicitly specifying the four control points required to define
3088 a third-order Bézier curve.
3090 Third-order or cubic Bézier curves are defined by four control
3091 points. The first and fourth control points are precisely the
3092 starting and ending points of the curve. The intermediate two
3093 control points define the shape. Animations showing how the curve
3094 is drawn can be found on the web, but the following description
3095 may be helpful. The curve starts from the first control point
3096 heading directly towards the second, gradually bending over to
3097 head towards the third and continuing to bend over to head towards
3098 the fourth, arriving there travelling directly from the third
3099 control point. The curve is entirely contained in the
3100 quadrilateral defined by the four control points.
3102 Here is an example of a case where the tie is not optimum, and
3103 where @code{\tieDown} would not help.
3105 @lilypond[verbatim,quote,relative=1]
3109 { r4 <g c,> <g c,> <g c,> }
3113 One way of improving this tie is to manually modify its control
3116 The coordinates of the Bézier control points are specified in units
3117 of staff-spaces. The X@tie{}coordinate is relative to the reference
3118 point of the note to which the tie or slur is attached, and the
3119 Y@tie{}coordinate is relative to the staff center line. The
3120 coordinates are entered as a list of four pairs of decimal numbers
3121 (reals). One approach is to estimate the coordinates of the two
3122 end points, and then guess the two intermediate points. The optimum
3123 values are then found by trial and error.
3125 It is useful to remember that a symmetric curve requires symmetric
3126 control points, and that Bézier curves have the useful property that
3127 transformations of the curve such as translation, rotation and
3128 scaling can be achieved by applying the same transformation to the
3129 curve's control points.
3131 For the example above the following override gives a satisfactory
3134 @lilypond[verbatim,quote,relative=1]
3137 #'control-points = #'((1 . -1) (3 . 0.6) (12.5 . 0.6) (14.5 . -1))
3140 { r4 <g c,> <g c,> <g c,>4 }
3146 It is not possible to modify shapes of ties or slurs by changing
3147 the @code{control-points} property if there are more than one at
3148 the same musical moment, not even by using the @code{\tweak}