@c -*- coding: utf-8; mode: texinfo; -*- @c This file is part of lilypond.tely @ignore Translation of GIT committish: FILL-IN-HEAD-COMMITTISH When revising a translation, copy the HEAD committish of the version that you are working on. See TRANSLATION for details. @end ignore @c \version "2.11.55" @node Changing defaults @chapter Changing defaults @strong{N.B. This Chapter is under heavy development at present.} The purpose of LilyPond's design is to provide the finest output quality as a default. Nevertheless, it may happen that you need to change this default layout. The layout is controlled through a large number of proverbial @q{knobs and switches.} This chapter does not list each and every knob. Rather, it outlines what groups of controls are available and explains how to lookup which knob to use for a particular effect. @cindex Internals Reference The controls available for tuning are described in a separate document, the @iftex Internals Reference manual. @end iftex @ifnottex @ref{Top,Internals Reference,,lilypond-internals}. @end ifnottex That manual lists all different variables, functions and options available in LilyPond. It is written as a HTML document, which is available @c leave the @uref as one long line. @uref{http://@/lilypond@/.org/@/doc/@/stable/@/Documentation/@/user/@/lilypond@/-internals/,on@/-line}, but is also included with the LilyPond documentation package. There are four areas where the default settings may be changed: @itemize @item Automatic notation: changing the automatic creation of notation elements. For example, changing the beaming rules. @item Output: changing the appearance of individual objects. For example, changing stem directions or the location of subscripts. @item Context: changing aspects of the translation from music events to notation. For example, giving each staff a separate time signature. @item Page layout: changing the appearance of the spacing, line breaks, and page dimensions. These modifications are discussed @c in @ref{notation}, and @ref{Spacing issues}. @end itemize Internally, LilyPond uses Scheme (a LISP dialect) to provide infrastructure. Overriding layout decisions in effect accesses the program internals, which requires Scheme input. Scheme elements are introduced in a @code{.ly} file with the hash mark @code{#}.@footnote{@rlearning{Scheme tutorial}, contains a short tutorial on entering numbers, lists, strings, and symbols in Scheme.} @menu * Interpretation contexts:: * Explaining the Internals Reference:: * Modifying properties:: * Useful concepts and properties:: * Common properties:: * Advanced tweaks:: * Discussion of specific tweaks:: @end menu @node Interpretation contexts @section Interpretation contexts This section describes what contexts are, and how to modify them. @menu * Contexts explained:: * Creating contexts:: * Modifying context plug-ins:: * Changing context default settings:: * Defining new contexts:: * Aligning contexts:: @end menu @node Contexts explained @subsection Contexts explained @ignore @c TODO Rethink and rewrite >> > > - list of contexts: my *danger unmaintainable* >> > > alarm just went off. I'm I knew it would... And leaving out some of them is perfectly fine with me. I do think that a list like this, with the main contexts and a brief description of what they do (perhaps also with a note about what default behavior is associated with each of them, but this may be unmanageable), should be there, and then we could simply list the remaining ones without further explanation and with links to the IR. @end ignore @c TODO Improve layout, order and consistency of wording -td @c TODO Add introduction which explains contexts in generality -td Contexts are arranged heirarchically: @menu * Score - the master of all contexts:: * Top-level contexts - staff containers:: * Intermediate-level contexts - staves:: * Bottom-level contexts - voices:: @end menu @node Score - the master of all contexts @unnumberedsubsubsec Score - the master of all contexts This is the top level notation context. No other context can contain a Score context. By default the Score context handles the administration of time signatures and makes sure that items such as clefs, time signatures, and key-signatures are aligned across staves. A Score context is instantiated implicitly when a @code{\score @{@dots{}@}} or @code{\layout @{@dots{}@}} block is processed, or explicitly when a @code{\new Score} command is executed. @node Top-level contexts - staff containers @unnumberedsubsubsec Top-level contexts - staff containers @strong{@emph{StaffGroup}} Groups staves while adding a bracket on the left side, grouping the staves together. The bar lines of the contained staves are connected vertically. StaffGroup only consists of a collection of staves, with a bracket in front and spanning bar lines. @strong{@emph{ChoirStaff}} Identical to StaffGroup except that the bar lines of the contained staves are not connected vertically. @strong{@emph{GrandStaff}} A group of staves, with a brace on the left side, grouping the staves together. The bar lines of the contained staves are connected vertically. @strong{@emph{PianoStaff}} TODO No longer correct? Check. -td Just like GrandStaff but with a forced distance between the staves, so cross staff beaming and slurring can be used. @strong{@emph{InnerStaffGroup}} TODO -td @strong{@emph{InnerChoirStaff}} TODO -td @node Intermediate-level contexts - staves @unnumberedsubsubsec Intermediate-level contexts - staves @strong{@emph{Staff}} Handles clefs, bar lines, keys, accidentals. It can contain Voice contexts. @strong{@emph{RhythmicStaff}} Like Staff but for printing rhythms. Pitches are ignored; the notes are printed on one line. @strong{@emph{TabStaff}} Context for generating tablature. By default lays the music expression out as a guitar tablature, printed on six lines. @strong{@emph{DrumStaff}} Handles typesetting for percussion. Can contain DrumVoice @strong{@emph{VaticanaStaff}} Same as Staff, except that it is designed for typesetting a piece in gregorian style. @strong{@emph{MensuralStaff}} Same as Staff, except that it is designed for typesetting a piece in mensural style. @node Bottom-level contexts - voices @unnumberedsubsubsec Bottom-level contexts - voices Voice-level contexts initialise certain properties and start appropriate engravers. Being bottom-level contexts, they cannot contain other contexts. @strong{@emph{Voice}} Corresponds to a voice on a staff. This context handles the conversion of dynamic signs, stems, beams, super- and sub-scripts, slurs, ties, and rests. You have to instantiate this explicitly if you require multiple voices on the same staff. @strong{@emph{VaticanaVoice}} Same as Voice, except that it is designed for typesetting a piece in gregorian style. @strong{@emph{MensuralVoice}} Same as Voice, with modifications for typesetting a piece in mensural style. @strong{@emph{Lyrics}} Corresponds to a voice with lyrics. Handles the printing of a single line of lyrics. @strong{@emph{DrumVoice}} The voice context used in a percussion staff. @strong{@emph{FiguredBass}} The context in which BassFigure objects are created from input entered in @code{\figuremode} mode. @strong{@emph{TabVoice}} The voice context used within a TabStaff context. Usually left to be created implicitly. @strong{@emph{ChordNames}} Typesets chord names. ------------------------------ TODO Then the following, which I don't know what to do with: * GregorianTranscriptionVoice * GregorianTranscriptionStaff * FretBoards Engraves fretboards from chords. Not easy... Not documented. There is now some documentation on FretBoards in the NR, under instrument-specific notation -- cds. * NoteNames * CueVoice Not documented * Global Hard coded entry point for LilyPond. Cannot be tuned. * Devnull Silently discards all musical information given to this context. @node Creating contexts @subsection Creating contexts @c TODO \new Score and \score @c TODO more complete descriptions rather than learning style For scores with only one voice and one staff, contexts are created automatically. For more complex scores, it is necessary to create them by hand. There are three commands that do this. @itemize @item The easiest command is @code{\new}, and it also the quickest to type. It is prepended to a music expression, for example @funindex \new @cindex new contexts @cindex Context, creating @example \new @var{type} @var{music expression} @end example @noindent where @var{type} is a context name (like @code{Staff} or @code{Voice}). This command creates a new context, and starts interpreting the @var{music expression} with that. A practical application of @code{\new} is a score with many staves. Each part that should be on its own staff, is preceded with @code{\new Staff}. @lilypond[quote,verbatim,relative=2,ragged-right,fragment] << \new Staff { c4 c } \new Staff { d4 d } >> @end lilypond The @code{\new} command may also give a name to the context, @example \new @var{type} = @var{id} @var{music} @end example However, this user specified name is only used if there is no other context already earlier with the same name. @funindex \context @item Like @code{\new}, the @code{\context} command also directs a music expression to a context object, but gives the context an explicit name. The syntax is @example \context @var{type} = @var{id} @var{music} @end example This form will search for an existing context of type @var{type} called @var{id}. If that context does not exist yet, a new context with the specified name is created. This is useful if the context is referred to later on. For example, when setting lyrics the melody is in a named context @example \context Voice = "@b{tenor}" @var{music} @end example @noindent so the texts can be properly aligned to its notes, @example \new Lyrics \lyricsto "@b{tenor}" @var{lyrics} @end example @noindent Another possible use of named contexts is funneling two different music expressions into one context. In the following example, articulations and notes are entered separately, @example music = @{ c4 c4 @} arts = @{ s4-. s4-> @} @end example They are combined by sending both to the same @code{Voice} context, @example << \new Staff \context Voice = "A" \music \context Voice = "A" \arts >> @end example @lilypond[quote,ragged-right] music = { c4 c4 } arts = { s4-. s4-> } \relative c'' << \new Staff \context Voice = "A" \music \context Voice = "A" \arts >> @end lilypond With this mechanism, it is possible to define an Urtext (original edition), with the option to put several distinct articulations on the same notes. @cindex creating contexts @item The third command for creating contexts is @example \context @var{type} @var{music} @end example @noindent This is similar to @code{\context} with @code{= @var{id}}, but matches any context of type @var{type}, regardless of its given name. This variant is used with music expressions that can be interpreted at several levels. For example, the @code{\applyOutput} command (see @ref{Running a function on all layout objects}). Without an explicit @code{\context}, it is usually applied to @code{Voice} @example \applyOutput #'@var{context} #@var{function} % apply to Voice @end example To have it interpreted at the @code{Score} or @code{Staff} level use these forms @example \applyOutput #'Score #@var{function} \applyOutput #'Staff #@var{function} @end example @end itemize @node Modifying context plug-ins @subsection Modifying context plug-ins @c TODO Should this be Modifying engravers or Modifying contexts? Notation contexts (like @code{Score} and @code{Staff}) not only store properties, they also contain plug-ins called @q{engravers} that create notation elements. For example, the @code{Voice} context contains a @code{Note_head_engraver} and the @code{Staff} context contains a @code{Key_signature_engraver}. For a full a description of each plug-in, see @ifhtml @rinternals{Engravers and Performers}. @end ifhtml @ifnothtml Internals Reference @expansion{} Translation @expansion{} Engravers. @end ifnothtml Every context described in @ifhtml @rinternals{Contexts} @end ifhtml @ifnothtml Internals Reference @expansion{} Translation @expansion{} Context. @end ifnothtml lists the engravers used for that context. It can be useful to shuffle around these plug-ins. This is done by starting a new context with @code{\new} or @code{\context}, and modifying it, @funindex \with @example \new @var{context} \with @{ \consists @dots{} \consists @dots{} \remove @dots{} \remove @dots{} @emph{etc.} @} @{ @emph{..music..} @} @end example @noindent where the @dots{} should be the name of an engraver. Here is a simple example which removes @code{Time_signature_engraver} and @code{Clef_engraver} from a @code{Staff} context, @lilypond[quote,relative=1,verbatim,fragment] << \new Staff { f2 g } \new Staff \with { \remove "Time_signature_engraver" \remove "Clef_engraver" } { f2 g2 } >> @end lilypond In the second staff there are no time signature or clef symbols. This is a rather crude method of making objects disappear since it will affect the entire staff. This method also influences the spacing, which may or may not be desirable. More sophisticated methods of blanking objects are shown in @rlearning{Visibility and color of objects}. The next example shows a practical application. Bar lines and time signatures are normally synchronized across the score. This is done by the @code{Timing_translator} and @code{Default_bar_line_engraver}. This plug-in keeps an administration of time signature, location within the measure, etc. By moving these engraver from @code{Score} to @code{Staff} context, we can have a score where each staff has its own time signature. @cindex polymetric scores @cindex Time signatures, multiple @lilypond[quote,relative=1,ragged-right,verbatim,fragment] \new Score \with { \remove "Timing_translator" \remove "Default_bar_line_engraver" } << \new Staff \with { \consists "Timing_translator" \consists "Default_bar_line_engraver" } { \time 3/4 c4 c c c c c } \new Staff \with { \consists "Timing_translator" \consists "Default_bar_line_engraver" } { \time 2/4 c4 c c c c c } >> @end lilypond @node Changing context default settings @subsection Changing context default settings The adjustments of the previous subsections ( @ref{The \set command}, @ref{Modifying context plug-ins}, and @ref{Overview of modifying properties}) can also be entered separately from the music in the @code{\layout} block, @example \layout @{ @dots{} \context @{ \Staff \set fontSize = #-2 \override Stem #'thickness = #4.0 \remove "Time_signature_engraver" @} @} @end example The @code{\Staff} command brings in the existing definition of the staff context so that it can be modified. The statements @example \set fontSize = #-2 \override Stem #'thickness = #4.0 \remove "Time_signature_engraver" @end example @noindent affect all staves in the score. Other contexts can be modified analogously. The @code{\set} keyword is optional within the @code{\layout} block, so @example \context @{ @dots{} fontSize = #-2 @} @end example @noindent will also work. @knownissues It is not possible to collect context changes in a variable and apply them to a @code{\context} definition by referring to that variable. The @code{\RemoveEmptyStaffContext} will overwrite your current @code{\Staff} settings. If you wish to change the defaults for a staff which uses @code{\RemoveEmptyStaffContext}, you must do so after calling @code{\RemoveEmptyStaffContext}, ie @example \layout @{ \context @{ \RemoveEmptyStaffContext \override Stem #'thickness = #4.0 @} @} @end example TODO: add \with in here. @node Defining new contexts @subsection Defining new contexts Specific contexts, like @code{Staff} and @code{Voice}, are made of simple building blocks. It is possible to create new types of contexts with different combinations of engraver plug-ins. The next example shows how to build a different type of @code{Voice} context from scratch. It will be similar to @code{Voice}, but only prints centered slash note heads. It can be used to indicate improvisation in jazz pieces, @lilypond[quote,ragged-right] \layout { \context { \name ImproVoice \type "Engraver_group" \consists "Note_heads_engraver" \consists "Text_engraver" \consists Pitch_squash_engraver squashedPosition = #0 \override NoteHead #'style = #'slash \override Stem #'transparent = ##t \alias Voice } \context { \Staff \accepts "ImproVoice" }} \relative c'' { a4 d8 bes8 \new ImproVoice { c4^"ad lib" c c4 c^"undress" c_"while playing :)" c } a1 } @end lilypond These settings are defined within a @code{\context} block inside a @code{\layout} block, @example \layout @{ \context @{ @dots{} @} @} @end example In the following discussion, the example input shown should go in place of the @dots{} in the previous fragment. First it is necessary to define a name for the new context: @example \name ImproVoice @end example Since it is similar to the @code{Voice}, we want commands that work on (existing) @code{Voice}s to remain working. This is achieved by giving the new context an alias @code{Voice}, @example \alias Voice @end example The context will print notes and instructive texts, so we need to add the engravers which provide this functionality, @example \consists Note_heads_engraver \consists Text_engraver @end example but we only need this on the center line, @example \consists Pitch_squash_engraver squashedPosition = #0 @end example The @rinternals{Pitch_squash_engraver} modifies note heads (created by @rinternals{Note_heads_engraver}) and sets their vertical position to the value of @code{squashedPosition}, in this case@tie{}@code{0}, the center line. The notes look like a slash, and have no stem, @example \override NoteHead #'style = #'slash \override Stem #'transparent = ##t @end example All these plug-ins have to cooperate, and this is achieved with a special plug-in, which must be marked with the keyword @code{\type}. This should always be @rinternals{Engraver_group}, @example \type "Engraver_group" @end example Put together, we get @example \context @{ \name ImproVoice \type "Engraver_group" \consists "Note_heads_engraver" \consists "Text_engraver" \consists Pitch_squash_engraver squashedPosition = #0 \override NoteHead #'style = #'slash \override Stem #'transparent = ##t \alias Voice @} @end example @funindex \accepts Contexts form hierarchies. We want to hang the @code{ImproVoice} under @code{Staff}, just like normal @code{Voice}s. Therefore, we modify the @code{Staff} definition with the @code{\accepts} command, @example \context @{ \Staff \accepts ImproVoice @} @end example @funindex \denies The opposite of @code{\accepts} is @code{\denies}, which is sometimes needed when reusing existing context definitions. Putting both into a @code{\layout} block, like @example \layout @{ \context @{ \name ImproVoice @dots{} @} \context @{ \Staff \accepts "ImproVoice" @} @} @end example Then the output at the start of this subsection can be entered as @example \relative c'' @{ a4 d8 bes8 \new ImproVoice @{ c4^"ad lib" c c4 c^"undress" c c_"while playing :)" @} a1 @} @end example @node Aligning contexts @subsection Aligning contexts New contexts may be aligned above or below existing contexts. This could be useful in setting up a vocal staff (@rlearning{Vocal ensembles}) and in ossia, @c TODO Better example needed. Ref LM, and expand on it. @cindex ossia @findex alignAboveContext @findex alignBelowContext @lilypond[quote,ragged-right] ossia = { f4 f f f } \score{ \relative c' \new Staff = "main" { c4 c c c << \new Staff \with {alignAboveContext=main} \ossia { d8 f d f d f d f } >> } } @end lilypond @node Explaining the Internals Reference @section Explaining the Internals Reference @menu * Navigating the program reference:: * Layout interfaces:: * Determining the grob property:: * Naming conventions:: @end menu @node Navigating the program reference @subsection Navigating the program reference @c TODO remove this (it's in the LM) @c Replace with more factual directions Suppose we want to move the fingering indication in the fragment below: @lilypond[quote,fragment,relative=2,verbatim] c-2 \stemUp f @end lilypond If you visit the documentation on fingering instructions (in @ref{Fingering instructions}), you will notice: @quotation @strong{See also} Internals Reference: @rinternals{Fingering}. @end quotation @c outdated info; probably will delete. @ignore This fragment points to two parts of the program reference: a page on @code{FingerEvent} and one on @code{Fingering}. The page on @code{FingerEvent} describes the properties of the music expression for the input @code{-2}. The page contains many links forward. For example, it says @quotation Accepted by: @rinternals{Fingering_engraver}, @end quotation @noindent That link brings us to the documentation for the Engraver, the plug-in, which says @quotation This engraver creates the following layout objects: @rinternals{Fingering}. @end quotation In other words, once the @code{FingerEvent}s are interpreted, the @code{Fingering_engraver} plug-in will process them. @end ignore @ignore @c I can't figure out what this is supposed to mean. -gp The @code{Fingering_engraver} is also listed to create @rinternals{Fingering} objects, @c old info? it doesn't make any sense to me with our current docs. This is also the second bit of information listed under @b{See also} in the Notation manual. @end ignore @ifnothtml The programmer's reference is available as an HTML document. It is highly recommended that you read it in HTML form, either online or by downloading the HTML documentation. This section will be much more difficult to understand if you are using the PDF manual. @end ifnothtml Follow the link to @rinternals{Fingering}. At the top of the page, you will see @quotation Fingering objects are created by: @rinternals{Fingering_engraver} and @rinternals{New_fingering_engraver}. @end quotation By following related links inside the program reference, we can follow the flow of information within the program: @itemize @item @rinternals{Fingering}: @rinternals{Fingering} objects are created by: @rinternals{Fingering_engraver} @item @rinternals{Fingering_engraver}: Music types accepted: @rinternals{fingering-event} @item @rinternals{fingering-event}: Music event type @code{fingering-event} is in Music expressions named @rinternals{FingerEvent} @end itemize This path goes against the flow of information in the program: it starts from the output, and ends at the input event. You could also start at an input event, and read with the flow of information, eventually ending up at the output object(s). The program reference can also be browsed like a normal document. It contains chapters on @ifhtml @rinternals{Music definitions}, @end ifhtml @ifnothtml @code{Music definitions} @end ifnothtml on @rinternals{Translation}, and the @rinternals{Backend}. Every chapter lists all the definitions used and all properties that may be tuned. @node Layout interfaces @subsection Layout interfaces @cindex interface, layout @cindex layout interface @cindex grob The HTML page that we found in the previous section describes the layout object called @rinternals{Fingering}. Such an object is a symbol within the score. It has properties that store numbers (like thicknesses and directions), but also pointers to related objects. A layout object is also called a @emph{Grob}, which is short for Graphical Object. For more details about Grobs, see @rinternals{grob-interface}. The page for @code{Fingering} lists the definitions for the @code{Fingering} object. For example, the page says @quotation @code{padding} (dimension, in staff space): @code{0.5} @end quotation @noindent which means that the number will be kept at a distance of at least 0.5 of the note head. Each layout object may have several functions as a notational or typographical element. For example, the Fingering object has the following aspects @itemize @item Its size is independent of the horizontal spacing, unlike slurs or beams. @item It is a piece of text. Granted, it is usually a very short text. @item That piece of text is typeset with a font, unlike slurs or beams. @item Horizontally, the center of the symbol should be aligned to the center of the note head. @item Vertically, the symbol is placed next to the note and the staff. @item The vertical position is also coordinated with other superscript and subscript symbols. @end itemize Each of these aspects is captured in so-called @emph{interface}s, which are listed on the @rinternals{Fingering} page at the bottom @quotation This object supports the following interfaces: @rinternals{item-interface}, @rinternals{self-alignment-interface}, @rinternals{side-position-interface}, @rinternals{text-interface}, @rinternals{text-script-interface}, @rinternals{font-interface}, @rinternals{finger-interface}, and @rinternals{grob-interface}. @end quotation Clicking any of the links will take you to the page of the respective object interface. Each interface has a number of properties. Some of them are not user-serviceable (@q{Internal properties}), but others can be modified. We have been talking of @emph{the} @code{Fingering} object, but actually it does not amount to much. The initialization file (see @rlearning{Other sources of information}) @file{scm/@/define@/-grobs@/.scm} shows the soul of the @q{object}, @example (Fingering . ((padding . 0.5) (avoid-slur . around) (slur-padding . 0.2) (staff-padding . 0.5) (self-alignment-X . 0) (self-alignment-Y . 0) (script-priority . 100) (stencil . ,ly:text-interface::print) (direction . ,ly:script-interface::calc-direction) (font-encoding . fetaNumber) (font-size . -5) ; don't overlap when next to heads. (meta . ((class . Item) (interfaces . (finger-interface font-interface text-script-interface text-interface side-position-interface self-alignment-interface item-interface)))))) @end example @noindent As you can see, the @code{Fingering} object is nothing more than a bunch of variable settings, and the webpage in the Internals Reference is directly generated from this definition. @node Determining the grob property @subsection Determining the grob property @c TODO remove this (it's in the LM) @c Replace with more factual directions Recall that we wanted to change the position of the @b{2} in @lilypond[quote,fragment,relative=2,verbatim] c-2 \stemUp f @end lilypond Since the @b{2} is vertically positioned next to its note, we have to meddle with the interface associated with this positioning. This is done using @code{side-position-interface}. The page for this interface says @quotation @code{side-position-interface} Position a victim object (this one) next to other objects (the support). The property @code{direction} signifies where to put the victim object relative to the support (left or right, up or down?) @end quotation @cindex padding @noindent Below this description, the variable @code{padding} is described as @quotation @table @code @item padding (dimension, in staff space) Add this much extra space between objects that are next to each other. @end table @end quotation By increasing the value of @code{padding}, we can move the fingering away from the note head. The following command inserts 3 staff spaces of white between the note and the fingering: @example \once \override Voice.Fingering #'padding = #3 @end example Inserting this command before the Fingering object is created, i.e., before @code{c2}, yields the following result: @lilypond[quote,relative=2,fragment,verbatim] \once \override Voice.Fingering #'padding = #3 c-2 \stemUp f @end lilypond In this case, the context for this tweak is @code{Voice}. This fact can also be deduced from the program reference, for the page for the @rinternals{Fingering_engraver} plug-in says @quotation Fingering_engraver is part of contexts: @dots{} @rinternals{Voice} @end quotation @node Naming conventions @subsection Naming conventions Another thing that is needed, is an overview of the various naming conventions: scheme functions: lowercase-with-hyphens (incl. one-word names) scheme functions: ly:plus-scheme-style music events, music classes and music properties: as-scheme-functions Grob interfaces: scheme-style backend properties: scheme-style (but X and Y!) contexts (and MusicExpressions and grobs): Capitalized or CamelCase context properties: lowercaseFollowedByCamelCase engravers: Capitalized_followed_by_lowercase_and_with_underscores Which of these are conventions and which are rules? Which are rules of the underlying language, and which are LP-specific? @node Modifying properties @section Modifying properties @menu * Overview of modifying properties:: * The \set command:: * The \override command:: * \set versus \override:: * Objects connected to the input:: @end menu @node Overview of modifying properties @subsection Overview of modifying properties Each context is responsible for creating certain types of graphical objects. The settings used for printing these objects are also stored by context. By changing these settings, the appearance of objects can be altered. The syntax for this is @example \override @var{context}.@var{name} #'@var{property} = #@var{value} @end example Here @var{name} is the name of a graphical object, like @code{Stem} or @code{NoteHead}, and @var{property} is an internal variable of the formatting system (@q{grob property} or @q{layout property}). The latter is a symbol, so it must be quoted. The subsection @ref{Modifying properties}, explains what to fill in for @var{name}, @var{property}, and @var{value}. Here we only discuss the functionality of this command. The command @verbatim \override Staff.Stem #'thickness = #4.0 @end verbatim @noindent makes stems thicker (the default is 1.3, with staff line thickness as a unit). Since the command specifies @code{Staff} as context, it only applies to the current staff. Other staves will keep their normal appearance. Here we see the command in action: @lilypond[quote,verbatim,relative=2,fragment] c4 \override Staff.Stem #'thickness = #4.0 c4 c4 c4 @end lilypond The @code{\override} command changes the definition of the @code{Stem} within the current @code{Staff}. After the command is interpreted all stems are thickened. Analogous to @code{\set}, the @var{context} argument may be left out, causing the default context @code{Voice} to be used. Adding @code{\once} applies the change during one timestep only. @lilypond[quote,fragment,verbatim,relative=2] c4 \once \override Stem #'thickness = #4.0 c4 c4 @end lilypond The @code{\override} must be done before the object is started. Therefore, when altering @emph{Spanner} objects such as slurs or beams, the @code{\override} command must be executed at the moment when the object is created. In this example, @lilypond[quote,fragment,verbatim,relative=2] \override Slur #'thickness = #3.0 c8[( c \override Beam #'thickness = #0.6 c8 c]) @end lilypond @noindent the slur is fatter but the beam is not. This is because the command for @code{Beam} comes after the Beam is started, so it has no effect. Analogous to @code{\unset}, the @code{\revert} command for a context undoes an @code{\override} command; like with @code{\unset}, it only affects settings that were made in the same context. In other words, the @code{\revert} in the next example does not do anything. @example \override Voice.Stem #'thickness = #4.0 \revert Staff.Stem #'thickness @end example Some tweakable options are called @q{subproperties} and reside inside properties. To tweak those, use commands of the form @c leave this as a long long @example \override @var{context}.@var{name} #'@var{property} #'@var{subproperty} = #@var{value} @end example @noindent such as @example \override Stem #'details #'beamed-lengths = #'(4 4 3) @end example @seealso Internals: @rinternals{OverrideProperty}, @rinternals{RevertProperty}, @rinternals{PropertySet}, @rinternals{Backend}, and @rinternals{All layout objects}. @knownissues The back-end is not very strict in type-checking object properties. Cyclic references in Scheme values for properties can cause hangs or crashes, or both. @node The \set command @subsection The @code{\set} command @cindex properties @funindex \set @cindex changing properties Each context can have different @emph{properties}, variables contained in that context. They can be changed during the interpretation step. This is achieved by inserting the @code{\set} command in the music, @example \set @var{context}.@var{prop} = #@var{value} @end example For example, @lilypond[quote,verbatim,relative=2,fragment] R1*2 \set Score.skipBars = ##t R1*2 @end lilypond This command skips measures that have no notes. The result is that multi-rests are condensed. The value assigned is a Scheme object. In this case, it is @code{#t}, the boolean True value. If the @var{context} argument is left out, then the current bottom-most context (typically @code{ChordNames}, @code{Voice}, or @code{Lyrics}) is used. In this example, @lilypond[quote,verbatim,relative=2,fragment] c8 c c c \set autoBeaming = ##f c8 c c c @end lilypond @noindent the @var{context} argument to @code{\set} is left out, so automatic beaming is switched off in the current @rinternals{Voice}. Note that the bottom-most context does not always contain the property that you wish to change -- for example, attempting to set the @code{skipBars} property (of the bottom-most context, in this case @code{Voice}) will have no effect. @lilypond[quote,verbatim,relative=2,fragment] R1*2 \set skipBars = ##t R1*2 @end lilypond Contexts are hierarchical, so if a bigger context was specified, for example @code{Staff}, then the change would also apply to all @code{Voice}s in the current stave. The change is applied @q{on-the-fly}, during the music, so that the setting only affects the second group of eighth notes. @funindex \unset There is also an @code{\unset} command, @example \unset @var{context}.@var{prop} @end example @noindent which removes the definition of @var{prop}. This command removes the definition only if it is set in @var{context}, so @example \set Staff.autoBeaming = ##f @end example @noindent introduces a property setting at @code{Staff} level. The setting also applies to the current @code{Voice}. However, @example \unset Voice.autoBeaming @end example @noindent does not have any effect. To cancel this setting, the @code{\unset} must be specified on the same level as the original @code{\set}. In other words, undoing the effect of @code{Staff.autoBeaming = ##f} requires @example \unset Staff.autoBeaming @end example Like @code{\set}, the @var{context} argument does not have to be specified for a bottom context, so the two statements @example \set Voice.autoBeaming = ##t \set autoBeaming = ##t @end example @noindent are equivalent. @cindex \once Settings that should only apply to a single time-step can be entered with @code{\once}, for example in @lilypond[quote,verbatim,relative=2,fragment] c4 \once \set fontSize = #4.7 c4 c4 @end lilypond the property @code{fontSize} is unset automatically after the second note. A full description of all available context properties is in the program reference, see @ifhtml @rinternals{Tunable context properties}. @end ifhtml @ifnothtml Translation @expansion{} Tunable context properties. @end ifnothtml @node The \override command @subsection The @code{\override} command Commands which change output generally look like @example \override Voice.Stem #'thickness = #3.0 @end example @noindent To construct this tweak we must determine these bits of information: @itemize @item the context: here @code{Voice}. @item the layout object: here @code{Stem}. @item the layout property: here @code{thickness}. @item a sensible value: here @code{3.0}. @end itemize Some tweakable options are called @q{subproperties} and reside inside properties. To tweak those, use commands in the form @example \override Stem #'details #'beamed-lengths = #'(4 4 3) @end example @cindex internal documentation @cindex finding graphical objects @cindex graphical object descriptions @cindex tweaking @funindex \override @cindex internal documentation For many properties, regardless of the data type of the property, setting the property to false ( @code{##f} ) will result in turning it off, causing LilyPond to ignore that property entirely. This is particularly useful for turning off grob properties which may otherwise be causing problems. We demonstrate how to glean this information from the notation manual and the program reference. @node \set versus \override @subsection @code{\set} vs. @code{\override} We have seen two methods of changing properties: @code{\set} and @code{\override}. There are actually two different kinds of properties. Contexts can have properties, which are usually named in @code{studlyCaps}. They mostly control the translation from music to notation, eg. @code{localKeySignature} (for determining whether to print accidentals), @code{measurePosition} (for determining when to print a bar line). Context properties can change value over time while interpreting a piece of music; @code{measurePosition} is an obvious example of this. Context properties are modified with @code{\set}. There is a special type of context property: the element description. These properties are named in @code{StudlyCaps} (starting with capital letters). They contain the @q{default settings} for said graphical object as an association list. See @file{scm/@/define@/-grobs@/.scm} to see what kind of settings there are. Element descriptions may be modified with @code{\override}. @code{\override} is actually a shorthand; @example \override @var{context}.@var{name} #'@var{property} = #@var{value} @end example @noindent is more or less equivalent to @c leave this long line -gp @example \set @var{context}.@var{name} #'@var{property} = #(cons (cons '@var{property} @var{value}) 4-\tweak #'padding #10 -. @end lilypond As you can see, properties are set in the objects directly, without mentioning the grob name or context where this should be applied. This technique only works for objects that are directly connected to an @rinternals{Event} from the input, for example @itemize @item note heads, caused by chord-pitch (i.e., notes inside a chord) @item articulation signs, caused by articulation instructions @end itemize It notably does not work for stems and accidentals (these are caused by note heads, not by music events) or clefs (these are not caused by music inputs, but rather by the change of a property value). There are very few objects which are @emph{directly} connected to output. A normal note (like @code{c4}) is not directly connected to output, so @example \tweak #'color #red c4 @end example @noindent does not change color. See @ref{Displaying music expressions}, for details. @node Useful concepts and properties @section Useful concepts and properties @menu * Input modes:: * Direction and placement:: * Distances and measurements:: * Spanners:: @end menu @node Input modes @subsection Input modes The way in which the notation contained within an input file is interpreted is determined by the current input mode. @strong{Chord mode} This is activated with the @code{\chordmode} command, and causes input to be interpreted with the syntax of chord notation, see @ref{Chord notation}. Chords are rendered as notes on a staff. Chord mode is also activated with the @code{\chords} command. This also creates a new @code{ChordNames} context and causes the following input to be interpreted with the syntax of chord notation and rendered as chord names in the @code{ChordNames} context, see @ref{Printing chord names}. @strong{Drum mode} This is activated with the @code{\drummode} command, and causes input to be interpreted with the syntax of drum notation, see @ref{Basic percussion notation}. Drum mode is also activated with the @code{\drums} command. This also creates a new @code{DrumStaff} context and causes the following input to be interpreted with the syntax of drum notation and rendered as drum symbols on a drum staff, see @ref{Basic percussion notation}. @strong{Figure mode} This is activated with the @code{\figuremode} command, and causes input to be interpreted with the syntax of figured bass, see @ref{Entering figured bass}. Figure mode is also activated with the @code{\figures} command. This also creates a new @code{FiguredBass} context and causes the following input to be interpreted with the figured bass syntax and rendered as figured bass symbols in the @code{FiguredBass} context, see @ref{Introduction to figured bass}. @strong{Fret and tab modes} There are no special input modes for entering fret and tab symbols. To create tab diagrams, enter notes or chords in note mode and render them in a @code{TabStaff} context, see @ref{Default tablatures}. To create fret diagrams above a staff, you have two choices. You can either use the @code{FretBoards} context (see @ref{Automatic fret diagrams} or you can enter them as a markup above the notes using the @code{\fret-diagram} command (see @ref{Fret diagram markups}). @strong{Lyrics mode} This is activated with the @code{\lyricmode} command, and causes input to be interpreted as lyric syllables with optional durations and associated lyric modifiers, see @ref{Vocal music}. Lyric mode is also activated with the @code{\addlyrics} command. This also creates a new @code{Lyrics} context and an implicit @code{\lyricsto} command which associates the following lyrics with the preceding music. @strong{Markup mode} This is activated with the @code{\markup} command, and causes input to be interpreted with the syntax of markup, see @ref{Text markup commands}. @c silly work-around for texinfo broken-ness @c (@strong{Note...} causes a spurious cross-reference in Info) @b{Note mode} This is the default mode or it may be activated with the @code{\notemode} command. Input is interpreted as pitches, durations, markup, etc and typeset as musical notation on a staff. It is not normally necessary to specify note mode explicitly, but it may be useful to do so in certain situations, for example if you are in lyric mode, chord mode or any other mode and want to insert something that only can be done with note mode syntax. For example, to indicate dynamic markings for the verses of a choral pieces it is necessary to enter note mode to interpret the markings: @lilypond[verbatim,relative=2,quote] { c4 c4 c4 c4 } \addlyrics { \notemode{\set stanza = \markup{ \dynamic f 1. } } To be sung loudly } \addlyrics { \notemode{\set stanza = \markup{ \dynamic p 2. } } To be sung quietly } @end lilypond @node Direction and placement @subsection Direction and placement In typesetting music the direction and placement of many items is a matter of choice. For example, the stems of notes can be directed up or down; lyrics, dynamics, and other expressive marks may be placed above or below the staff; text may be aligned left, right or center; etc. Most of these choices may be left to be determined automatically by LilyPond, but in some cases it may be desirable to force a particular direction or placement. @strong{Default actions} By default some directions are always up or always down (e.g. dynamics or fermata), while other things can alternate between up or down based on the stem direction (like slurs or accents). @c TODO Add table showing these @strong{Context layout} Contexts are positioned in a system from top to bottom in the order in which they are encountered. Note, however, that a context will be created implicitly if a command is encountered when there is no suitable context available to contain it. @c TODO Add example ? The default order in which contexts are laid out can be changed, see @ref{Aligning contexts} @strong{Articulation direction indicators} When adding articulations to notes the direction indicator, @code{^} (meaning @qq{up}), @code{_} (meaning @qq{down}) or @code{-} (meaning @qq{use default direction}), can usually be omitted, in which case @code{-} is assumed. But a direction indicator is @strong{always} required before @itemize @item @code{\tweak} commands @item @code{\markup} commands @item @code{\tag} commands @item string markups, e.g. -"string" @item fingering instructions, e.g. @code{-1} @item articulation shortcuts, e.g. @code{-.}, @code{->}, @code{--} @end itemize @strong{The direction property} The position or direction of many layout objects is controlled by the @code{direction} property. The value of the @code{direction} property may be set to @code{1}, meaning @qq{up} or @qq{above}, or to @code{-1}, meaning @qq{down} or @qq{below}. The symbols @code{UP} and @code{DOWN} may be used instead of @code{1} and @code{-1} respectively. The default direction may be specified by setting @code{direction} to @code{0} or @code{CENTER}. Alternatively, in many cases predefined commands exist to specify the direction. These are all of the form @noindent @code{\xxxUp}, @code{xxxDown}, @code{xxxNeutral} @noindent where @code{xxxNeutral} means @qq{use the default direction}. See @rlearning{Within-staff objects}. In a few cases, arpeggio being the only common example, the value of the @code{direction} property specifies whether the object is to be placed to the right or left of the parent object. In this case @code{-1} or @code{LEFT} means @qq{to the left} and @code{1} or @code{RIGHT} means @qq{to the right}. @code{0} or @code{CENTER} means @qq{use the default} direction, as before. @ignore These all have side-axis set to #X AmbitusAccidental - direction has no effect Arpeggio - works StanzaNumber - not tried TrillPitchAccidental - not tried TrillPitchGroup - not tried @end ignore @node Distances and measurements @subsection Distances and measurements DISCUSS after working on other sections. TODO: staff spaces. Maybe move into tweaks? @node Spanners @subsection Spanners Many objects of musical notation extend over several notes or even several bars. Examples are crescendi, trills, tuplet brackets, and volta repeat brackets. Such objects are called @qq{spanners}, and have special properties to control their appearance and behaviour. Some of these properties are common to all spanners; others are restricted to a sub-set of the spanners. @node Common properties @section Common properties @menu * Controlling visibility of objects:: * Line styles:: * Rotating objects:: * Aligning objects:: @end menu @c TODO Add new subsection Shapes of objects @c which would include Slur shapes @c with a Known issue: can't modify shapes with 'control-points if there are @c more than one at the same musical moment @node Controlling visibility of objects @subsection Controlling visibility of objects @cindex objects, visibility of @cindex grobs, visibility of @cindex visibility of objects There are four main ways in which the visibility of layout objects can be controlled: their stencil can be removed, they can be made transparent, they can be colored white, or their @code{break-visibility} property can be overridden. The first three apply to all layout objects; the last to just a few -- the @emph{breakable} objects. The Learning Manual introduces these four techniques, see @rlearning{Visibility and color of objects}. There are also a few other techniques which are specific to certain layout objects. These are covered under Special considerations. @menu * Removing the stencil:: * Making objects transparent:: * Painting objects white:: * Using break-visibility:: * Special considerations:: @end menu @node Removing the stencil @unnumberedsubsubsec Removing the stencil @cindex stencil, removing Every layout object has a stencil property. By default this is set to the specific function which draws that object. If this property is overridden to @code{#f} no function will be called and the object will not be drawn. The default action can be recovered with @code{\revert}. @lilypond[quote,verbatim,relative=1] a1 a \override Score.BarLine #'stencil = ##f a a \revert Score.BarLine #'stencil a a a @end lilypond @node Making objects transparent @unnumberedsubsubsec Making objects transparent @cindex transparent, making objects Every layout object has a transparent property which by default is set to @code{#f}. If set to @code{#t} the object still occupies space but is made invisible. @lilypond[quote,verbatim,relative=2] a4 a \once \override NoteHead #'transparent = ##t a a @end lilypond @node Painting objects white @unnumberedsubsubsec Painting objects white @cindex objects, coloring @cindex coloring objects @cindex layers @cindex printing order @cindex overwriting objects @cindex objects, overwriting @cindex grobs, overwriting Every layout object has a color property which by default is set to @code{black}. If this is overridden to @code{white} the object will be indistinguishable from the white background. However, if the object crosses other objects the color of the crossing points will be determined by the order in which they are drawn, and this may leave a ghostly image of the white object, as shown here: @lilypond[quote,verbatim,relative=2] \override Staff.Clef #'color = #white a1 @end lilypond This may be avoided by changing the order of printing the objects. All layout objects have a @code{layer} property which takes a real number. Objects with the lowest value of @code{layer} are drawn first, then objects with progressively higher values are drawn, so objects with higher values overwrite objects with lower values. By default most objects are assigned a @code{layer} value of @code{1}, although a few objects, including @code{StaffSymbol} and @code{BarLine}, are assigned a value of @code{0}. The order of printing objects with the same nominal value of @code{layer} is indeterminate. In the example above the white clef, with a default @code{layer} value of @code{1}, is drawn after the staff lines (default @code{layer} value @code{0}), so overwriting them. To change this, the @code{Clef} object must be given in a lower value of @code{layer}, say @code{-1}, so that it is drawn earlier: @lilypond[quote,verbatim,relative=2] \override Staff.Clef #'color = #white \override Staff.Clef #'layer = #-1 a1 @end lilypond @node Using break-visibility @unnumberedsubsubsec Using break-visibility @cindex break-visibility Most layout objects are printed only once, but some like bar lines, clefs, time signatures and key signatures, may need to be printed twice when a line break occurs -- once at the end of the line and again at the start of the next line. Such objects are called @emph{breakable}, and have a property, the @code{break-visibility} property to control their visibility at the three positions in which they may appear -- at the start of a line, within a line if they are changed, and at the end of a line if a change takes place there. For example, the time signature by default will be printed at the start of the first line, but nowhere else unless it changes, when it will be printed at the point at which the change occurs. If this change occurs at the end of a line the new time signature will be printed at the start of the next line and a cautionary time signature will be printed at the end of the previous line as well. This behaviour is controlled by the @code{break-visibility} property, which is explained in @rlearning{Visibility and color of objects}. This property takes a vector of three booleans which, in order, determine whether the object is printed at the end of, within the body of, or at the beginning of a line. Or to be more precise, before a line break, where there is no line break, or after a line break. Alternatively, seven of the eight combinations may be specified by pre-defined functions, defined in @file{scm/output-lib.scm}, where the last three columns indicate whether the layout objects will be visible in the positions shown at the head of the columns: @multitable @columnfractions .40 .15 .15 .15 .15 @c TODO check these more carefully @headitem Function @tab Vector @tab Before @tab At no @tab After @headitem form @tab form @tab break @tab break @tab break @item @code{all-invisible} @tab @code{'#(#f #f #f)} @ @ @tab no @tab no @tab no @item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes @item @code{end-of-line-visible} @tab @code{'#(#t #f #f)} @tab yes @tab no @tab no @item @code{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes @c The center-visible function is not defined @c @item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no @item @code{begin-of-line-invisible} @tab @code{'#(#t #t #f)} @tab yes @tab yes @tab no @item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes @item @code{center-invisible} @tab @code{'#(#t #f #t)} @tab yes @tab no @tab yes @end multitable The @code{center-visible} function is not pre-defined. The default settings of @code{break-visibility} depend on the layout object. The following table shows all the layout objects of interest which are affected by @code{break-visibility} and the default setting of this property: @multitable @columnfractions .3 .3 .4 @headitem Layout object @tab Usual context @tab Default setting @c omit Ambitus as it appears not to be affected by break-visibility -td @c @item @code{Ambitus} @tab as specified @tab @code{begin-of-line-visible} @item @code{BarLine} @tab @code{Score} @tab calculated @item @code{BarNumber} @tab @code{Score} @tab @code{begin-of-line-visible} @c omit the following item until it can be explained -td @c @item @code{BreakAlignGroup} @tab @code{Score} @tab calculated @item @code{BreathingSign} @tab @code{Voice} @tab @code{begin-of-line-invisible} @item @code{Clef} @tab @code{Staff} @tab @code{begin-of-line-visible} @item @code{Custos} @tab @code{Staff} @tab @code{end-of-line-visible} @item @code{DoublePercentRepeat} @tab @code{Voice} @tab @code{begin-of-line-invisible} @c omit KeyCancellation until it can be explained -td @c @item @code{KeyCancellation} @tab ?? @tab @code{begin-of-line-invisible} @item @code{KeySignature} @tab @code{Staff} @tab @code{begin-of-line-visible} @c omit LeftEdge until it can be explained -td @c @item @code{LeftEdge} @tab @code{Score} @tab @code{center-invisible} @item @code{OctavateEight} @tab @code{Staff} @tab @code{begin-of-line-visible} @item @code{RehearsalMark} @tab @code{Score} @tab @code{end-of-line-invisible} @item @code{TimeSignature} @tab @code{Staff} @tab @code{all-visible} @end multitable The example below shows the use of the vector form to control the visibility of barlines: @lilypond[quote,verbatim,relative=1,ragged-right] f4 g a b f4 g a b % Remove bar line at the end of the current line \once \override Score.BarLine #'break-visibility = #'#(#f #t #t) \break f4 g a b f4 g a b @end lilypond Although all three components of the vector used to override @code{break-visibility} must be present, not all of them are effective with every layout object, and some combinations may even give errors. The following limitations apply: @itemize @bullet @item Bar lines cannot be printed at start of line. @item A bar number cannot be printed at the start of the first line unless it is set to be different from 1. @item Clef -- see below @item Double percent repeats are either all printed or all suppressed. Use begin-of line-invisible to print and all-invisible to suppress. @item Key signature -- see below @item OctavateEight -- see below @end itemize @node Special considerations @unnumberedsubsubsec Special considerations @strong{@emph{Visibility following explicit changes}} @cindex key signature, visibility following explicit change @cindex explicitKeySignatureVisibility @cindex clef, visibility following explicit change @cindex explicitClefVisibility The @code{break-visibility} property controls the visibility of key signatures and changes of clef only at the start of lines, i.e. after a break. It has no effect on the visibility of the key signature or clef following an explicit key change or an explicit clef change within or at the end of a line. In the following example the key signature following the explicit change to B-flat major is still visible, even though @code{all-invisible} is set. @lilypond[quote,verbatim,relative=1,ragged-right] \key g \major f4 g a b % Try to remove all key signatures \override Staff.KeySignature #'break-visibility = #all-invisible \key bes \major f4 g a b \break f4 g a b f4 g a b @end lilypond The visibility of such explicit key signature and clef changes is controlled by the @code{explicitKeySignatureVisibility} and @code{explicitClefVisibility} properties. These are the equivalent of the @code{break-visibility} property and both take a vector of three booleans or the predefined functions listed above, exactly like @code{break-visibility}. Both are properties of the Staff context, not the layout objects themselves, and so they are set using the @code{\set} command. Both are set by default to @code{all-visible}. These properties control only the visibility of key signatures and clefs resulting from explicit changes and do not affect key signatures and clefs at the beginning of lines; @code{break-visibility} must still be overridden in the appropriate object to remove these. @lilypond[quote,verbatim,relative=1,ragged-right] \key g \major f4 g a b \set Staff.explicitKeySignatureVisibility = #all-invisible \override Staff.KeySignature #'break-visibility = #all-invisible \key bes \major f4 g a b \break f4 g a b f4 g a b @end lilypond @strong{@emph{Visibility of cautionary accidentals}} To remove the cautionary accidentals printed at an explicit key change, set the Staff context property @code{printKeyCancellation} to @code{#f}: @lilypond[quote,verbatim,relative=1,ragged-right] \key g \major f4 g a b \set Staff.explicitKeySignatureVisibility = #all-invisible \set Staff.printKeyCancellation = ##f \override Staff.KeySignature #'break-visibility = #all-invisible \key bes \major f4 g a b \break f4 g a b f4 g a b @end lilypond With these overrides only the accidentals before the notes remain to indicate the change of key. @c TODO Add visibility of cautionary accidentals before notes @strong{@emph{Automatic bars}} @cindex automaticBars @cindex bar lines, suppressing As a special case, the printing of bar lines can also be turned off by setting the @code{automaticBars} property in the Score context. If set to @code{#f}, bar lines will not be printed automatically; they must be explicitly created with a @code{\bar} command. Unlike the @code{\cadenzaOn} predefined command, measures are still counted. Bar generation will resume according to that count if this property is later set to @code{#t}. When set to @code{#f}, line breaks can occur only at explicit @code{\bar} commands. @c TODO Add example @strong{@emph{Octavated clefs}} @cindex octavated clefs, visibility of @cindex visibility of octavated clefs @cindex clefs, visibility of octavation The small octavation symbol on octavated clefs is produced by the @code{OctavateEight} layout object. Its visibility is controlled independently from that of the @code{Clef} object, so it is necessary to apply any required @code{break-visibility} overrides to both the @code{Clef} and the @code{OctavateEight} layout objects to fully suppress such clef symbols at the start of each line. For explicit clef changes, the @code{explicitClefVisibility} property controls both the clef symbol and any octavation symbol associated with it. @seealso Learning Manual: @rlearning{Visibility and color of objects} @node Line styles @subsection Line styles @c TODO: split the following explanations between expressive marks and @c text-related stuff. Perhaps create a new subsection named @c "Spanner limits", "Spanner boundaries"? -vv Some performance indications, e.g., @i{rallentando} and @i{accelerando} and @i{trills} are written as text and are extended over many measures with lines, sometimes dotted or wavy. These all use the same routines as the glissando for drawing the texts and the lines, and tuning their behavior is therefore also done in the same way. It is done with a spanner, and the routine responsible for drawing the spanners is @code{ly:line-interface::print}. This routine determines the exact location of the two @i{span points} and draws a line in between, in the style requested. Here is an example of the different line styles available, and how to tune them. @lilypond[relative=2,ragged-right,verbatim,fragment] d2 \glissando d'2 \once \override Glissando #'style = #'dashed-line d,2 \glissando d'2 \override Glissando #'style = #'dotted-line d,2 \glissando d'2 \override Glissando #'style = #'zigzag d,2 \glissando d'2 \override Glissando #'style = #'trill d,2 \glissando d'2 @end lilypond The information that determines the end-points is computed on-the-fly for every graphic object, but it is possible to override these. @lilypond[relative=2,ragged-right,verbatim,fragment] e2 \glissando f \once \override Glissando #'bound-details #'right #'Y = #-2 e2 \glissando f @end lilypond The @code{Glissando} object, like any other using the @code{ly:line-interface::print} routine, carries a nested association list. In the above statement, the value for @code{Y} is set to @code{-2} for the association list corresponding to the right end point. Of course, it is also possible to adjust the left side with @code{left} instead of @code{right}. If @code{Y} is not set, the value is computed from the vertical position of right attachment point of the spanner. In case of a line break, the values for the span-points are extended with contents of the @code{left-broken} and @code{right-broken} sublists, for example @lilypond[relative=2,ragged-right,verbatim,fragment] \override Glissando #'breakable = ##T \override Glissando #'bound-details #'right-broken #'Y = #-3 c1 \glissando \break f1 @end lilypond The following properties can be used for the @table @code @item Y This sets the Y-coordinate of the end point, in staff space. By default, it is the center of the bound object, so for a glissando it points to the vertical center of the note head. For horizontal spanners, such as text spanner and trill spanners, it is hardcoded to 0. @item attach-dir This determines where the line starts and ends in X-direction, relative to the bound object. So, a value of @code{-1} (or @code{LEFT}) makes the line start/end at the left side of the note head it is attached to. @item X This is the absolute coordinate of the end point. It is usually computed on the fly, and there is little use in overriding it. @item stencil Line spanners may have symbols at the beginning or end, which is contained in this sub-property. This is for internal use, it is recommended to use @code{text}. @item text This is a markup that is evaluated to yield stencil. It is used to put @i{cresc.} and @i{tr} on horizontal spanners. @lilypond[quote,ragged-right,fragment,relative=2,verbatim] \override TextSpanner #'bound-details #'left #'text = \markup { \small \bold Slower } c2\startTextSpan b c a\stopTextSpan @end lilypond @item stencil-align-dir-y @item stencil-offset Without setting this, the stencil is simply put there at the end-point, as defined by the @code{X} and @code{Y} sub properties. Setting either @code{stencil-align-dir-y} or @code{stencil-offset} will move the symbol at the edge relative to the end point of the line @lilypond[relative=1,fragment,verbatim] \override TextSpanner #'bound-details #'left #'stencil-align-dir-y = #DOWN \override TextSpanner #'bound-details #'right #'stencil-align-dir-y = #UP \override TextSpanner #'bound-details #'left #'text = #"gggg" \override TextSpanner #'bound-details #'right #'text = #"hhhh" c4^\startTextSpan c c c \stopTextSpan @end lilypond @item arrow Setting this sub property to @code{#t} produce an arrowhead at the end of the line. @item padding This sub property controls the space between the specified end-point of the line and the actual end. Without padding, a glissando would start and end in the center of each note head. @end table @c TODO: Move to 5.4.4 The music function \endSpanners terminates spanners and hairpins after exactly one note. @lilypond[verbatim,quote,ragged-right,relative=2,fragment] \endSpanners c2 \startTextSpan c2 c2 \< c2 @end lilypond When using \endSpanners it is not necessary to close \startTextSpan with \stopTextSpan, nor is it necessary to close hairpins with \!. @seealso Internals Reference: @rinternals{TextSpanner}, @rinternals{Glissando}, @rinternals{VoiceFollower}, @rinternals{TrillSpanner}, @rinternals{line-spanner-interface}. @node Rotating objects @subsection Rotating objects @c FIXME Write this section @node Aligning objects @subsection Aligning objects @c FIXME Write this section @node Advanced tweaks @section Advanced tweaks @menu * Vertical grouping of grobs:: * Modifying ends of spanners:: * Modifying stencils:: * Modifying shapes:: @end menu @node Vertical grouping of grobs @subsection Vertical grouping of grobs @c FIXME Expand this section The VerticalAlignment and VerticalAxisGroup grobs work together. VerticalAxisGroup groups together different grobs like Staff, Lyrics, etc. VerticalAlignment then vertically aligns the different grobs grouped together by VerticalAxisGroup. There is usually only one VerticalAlignment per score but every Staff, Lyrics, etc. has its own VerticalAxisGroup. @node Modifying ends of spanners @subsection Modifying ends of spanners @c FIXME Write this section @node Modifying stencils @subsection Modifying stencils @c FIXME Write this section @node Modifying shapes @subsection Modifying shapes @c FIXME Write this section @c Discussion of Bezier curves and the control-points property @node Discussion of specific tweaks @section Discussion of specific tweaks @menu * old Contexts explained:: @end menu @node old Contexts explained @subsection old Contexts explained @c FIXME Delete this section? It is in LM @c Or leave heading and go on from LM? When music is printed, a lot of notational elements must be added to the output. For example, compare the input and output of the following example: @lilypond[quote,verbatim,relative=2,fragment] cis4 cis2. g4 @end lilypond The input is rather sparse, but in the output, bar lines, accidentals, clef, and time signature are added. LilyPond @emph{interprets} the input. During this step, the musical information is inspected in time order, similar to reading a score from left to right. While reading the input, the program remembers where measure boundaries are, and which pitches require explicit accidentals. This information can be presented on several levels. For example, the effect of an accidental is limited to a single staff, while a bar line must be synchronized across the entire score. Within LilyPond, these rules and bits of information are grouped in @emph{Contexts}. Some examples of contexts are @code{Voice}, @code{Staff}, and @code{Score}. They are hierarchical, for example: a @code{Staff} can contain many @code{Voice}s, and a @code{Score} can contain many @code{Staff} contexts. @quotation @sourceimage{context-example,5cm,,} @end quotation Each context has the responsibility for enforcing some notation rules, creating some notation objects and maintaining the associated properties. For example, the @code{Voice} context may introduce an accidental and then the @code{Staff} context maintains the rule to show or suppress the accidental for the remainder of the measure. The synchronization of bar lines is handled at @code{Score} context. However, in some music we may not want the bar lines to be synchronized -- consider a polymetric score in 4/4 and 3/4 time. In such cases, we must modify the default settings of the @code{Score} and @code{Staff} contexts. For very simple scores, contexts are created implicitly, and you need not be aware of them. For larger pieces, such as anything with more than one staff, they must be created explicitly to make sure that you get as many staves as you need, and that they are in the correct order. For typesetting pieces with specialized notation, it can be useful to modify existing or to define new contexts. A complete description of all available contexts is in the program reference, see @ifhtml @rinternals{Contexts}. @end ifhtml @ifnothtml Translation @expansion{} Context. @end ifnothtml @c [TODO: describe propagation]