version that you are working on. See TRANSLATION for details.
@end ignore
-@c \version "2.11.55"
+@c \version "2.12.0"
@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
+The purpose of LilyPond's design is to provide the finest quality
+output by 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.
-
+number of @q{knobs and switches} collectively called @q{properties}.
+A tutorial introduction to accessing and modifying these properties
+can be found in the Learning Manual, see @rlearning{Tweaking output}.
+This should be read first. This chapter covers similar ground, but
+in a style more appropriate to a reference manual.
@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
+The definitive description of the controls available for tuning can
+be found in a separate document: @rinternalsnamed{Top,the Internals
+Reference}. That manual lists all the 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.
-
-@c TODO The following is at variance to what actually follows. Fix -td
-
-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
+and is also included with the LilyPond documentation package.
Internally, LilyPond uses Scheme (a LISP dialect) to provide
infrastructure. Overriding layout decisions in effect accesses the
* Explaining the Internals Reference::
* Modifying properties::
* Useful concepts and properties::
-* Common properties::
* Advanced tweaks::
-* Discussion of specific tweaks::
@end menu
@end menu
+@seealso
+Learning Manual:
+@rlearning{Contexts and engravers}.
+
+Installed files:
+@file{ly/@/engraver@/-init@/.ly},
+@file{ly/@/performer@/-init@/.ly}.
+
+Snippets:
+@rlsr{Contexts and engravers}.
+
+Internals Reference:
+@rinternals{Contexts},
+@rinternals{Engravers and Performers}.
+
+
@node Contexts explained
@subsection Contexts explained
@c TODO Add introduction which explains contexts in generality -td
-Contexts are arranged heirarchically:
+@c TODO Describe propagation of property values -td
+
+Contexts are arranged hierarchically:
@menu
* Score - the master of all contexts::
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
+connected vertically. @code{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.
+Identical to @code{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
+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
+Just like @code{GrandStaff}, but with support for instrument names
+to the left of each system.
@node Intermediate-level contexts - staves
@unnumberedsubsubsec Intermediate-level contexts - staves
@strong{@emph{Staff}}
-Handles clefs, bar lines, keys, accidentals. It can contain
-Voice contexts.
+Handles clefs, bar lines, keys, accidentals. It can contain
+@code{Voice} contexts.
@strong{@emph{RhythmicStaff}}
-Like Staff but for printing rhythms. Pitches are ignored;
+Like @code{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
+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
+Handles typesetting for percussion. Can contain @code{DrumVoice}
@strong{@emph{VaticanaStaff}}
-Same as Staff, except that it is designed for typesetting
+Same as @code{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
+Same as @code{Staff}, except that it is designed for typesetting
a piece in mensural style.
@node Bottom-level contexts - voices
@strong{@emph{Voice}}
-Corresponds to a voice on a staff. This context handles the
+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.
+Same as @code{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
+Same as @code{Voice}, with modifications for typesetting a piece in
mensural style.
@strong{@emph{Lyrics}}
-Corresponds to a voice with lyrics. Handles the printing of a
+Corresponds to a voice with lyrics. Handles the printing of a
single line of lyrics.
@strong{@emph{DrumVoice}}
@strong{@emph{FiguredBass}}
-The context in which BassFigure objects are created from
+The context in which @code{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.
+The voice context used within a @code{TabStaff} context. Usually
+left to be created implicitly.
@strong{@emph{ChordNames}}
Typesets chord names.
-------------------------------
-
+@ignore
TODO
Then the following, which I don't know what to do with:
Silently discards all musical information given to this
context.
+@end ignore
@node Creating contexts
@subsection Creating contexts
>>
@end lilypond
+@knownissues
-@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.
+Usually the order in which the engravers are specified
+does not matter, but in a few special cases the order
+is important, for example where one engraver writes
+a property and another reads it, or where one engraver
+creates a grob and another must process it. The order in
+which the engravers are specified is the order in which
+they are called to carry out their processing.
-The statements
-@example
-\set fontSize = #-2
-\override Stem #'thickness = #4.0
-\remove "Time_signature_engraver"
-@end example
+The following orderings are important: the
+@code{Bar_engraver} must normally be first, and
+the @code{New_fingering_engraver} must come before
+the @code{Script_column_engraver}. There may be others
+with ordering dependencies.
-@noindent
-affect all staves in the score. Other contexts can be modified
-analogously.
+@node Changing context default settings
+@subsection Changing context default settings
-The @code{\set} keyword is optional within the @code{\layout} block, so
+The context settings which are to be used by default in
+@code{Score}, @code{Staff} and @code{Voice} contexts may be specified
+in a @code{\layout} block, as illustrated in the following example.
+The @code{\layout} block should be placed within the @code{\score}
+block to which it is to apply, but outside any music.
-@example
-\context @{
- @dots{}
- fontSize = #-2
-@}
-@end example
+Note that the @code{\set} command itself and the context must be
+omitted when the context default values are specified in this way:
-@noindent
-will also work.
+@lilypond[quote,verbatim]
+\score {
+ \relative c'' {
+ a4^"Really small, thicker stems, no time signature" a a a
+ a a a a
+ }
+ \layout {
+ \context {
+ \Staff
+ fontSize = #-4
+ \override Stem #'thickness = #4.0
+ \remove "Time_signature_engraver"
+ }
+ }
+}
+@end lilypond
+In this example, the @code{\Staff} command specifies that the
+subsequent specifications are to be applied to all staves within
+this score block.
+Modifications can be made to the @code{Score} context or all
+@code{Voice} contexts in a similar way.
@knownissues
@}
@end example
-TODO: add \with in here.
+@c TODO: add \with in here.
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},
+This should always be @code{Engraver_group}.
@example
\type "Engraver_group"
@c TODO Better example needed. Ref LM, and expand on it.
@cindex ossia
-@findex alignAboveContext
-@findex alignBelowContext
+@funindex alignAboveContext
+@funindex alignBelowContext
@lilypond[quote,ragged-right]
ossia = { f4 f f f }
\relative c' \new Staff = "main" {
c4 c c c
<<
- \new Staff \with {alignAboveContext=main} \ossia
+ \new Staff \with { alignAboveContext = #"main" } \ossia
{ d8 f d f d f d f }
>>
}
}
@end lilypond
+@cindex nested contexts
+@cindex contexts, nested
+
+@funindex \accepts
+@funindex \denies
+
+Contexts like @code{PianoStaff} can contain other contexts
+nested within them. Contexts which are acceptable for nesting
+are defined by the @qq{accepts} list of a context. Contexts
+which are not in this list are placed below the outer context
+in the printed score.
+For example, the @code{PianoStaff} context is defined by default
+to accept @code{Staff} and @code{FiguredBass} contexts within
+it, but not (for example) a @code{Lyrics} context. So in the
+following structure the lyrics are placed below the piano staff
+rather than between the two staves:
+
+@lilypond[verbatim,quote,relative=1]
+\new PianoStaff
+<<
+ \new Staff { e4 d c2 }
+ \addlyrics { Three blind mice }
+ \new Staff {
+ \clef "bass"
+ { c,1 }
+ }
+>>
+@end lilypond
+
+The @qq{accepts} list of a context can be modified to include
+additional nested contexts, so if we wanted the lyrics to appear
+between the two staves we could use:
+
+@lilypond[verbatim,quote,relative=1]
+\new PianoStaff \with { \accepts Lyrics }
+<<
+ \new Staff { e4 d c2 }
+ \addlyrics { Three blind mice }
+ \new Staff {
+ \clef "bass"
+ { c,1 }
+ }
+>>
+@end lilypond
+
+The opposite of @code{\accepts} is @code{\denies}; this removes a
+context from the @qq{accepts} list.
@node Explaining the Internals Reference
@section Explaining the Internals Reference
@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}.
+on @code{FingeringEvent} and one on @code{Fingering}.
-The page on @code{FingerEvent} describes the properties of the music
+The page on @code{FingeringEvent} describes the properties of the music
expression for the input @code{-2}. The page contains many links
forward. For example, it says
This engraver creates the following layout objects: @rinternals{Fingering}.
@end quotation
-In other words, once the @code{FingerEvent}s are interpreted, the
+In other words, once the @code{FingeringEvent}s are interpreted, the
@code{Fingering_engraver} plug-in will process them.
@end ignore
@item @rinternals{fingering-event}:
Music event type @code{fingering-event} is in Music expressions named
-@rinternals{FingerEvent}
+@rinternals{FingeringEvent}
@end itemize
This path goes against the flow of information in the program: it
@node Modifying properties
@section Modifying properties
+@c TODO change the menu and subsection node names to use
+@c backslash once the new macro to handle the refs
+@c is available. Need to find and change all refs at
+@c the same time. -td
+
@menu
* Overview of modifying properties::
-* The \set command::
-* The \override command::
-* \set versus \override::
-* Objects connected to the input::
+* The set command::
+* The override command::
+* The tweak command::
+* set versus override::
@end menu
such as
@example
-\override Stem #'details #'beamed-lengths = #'(4 4 3)
+\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}.
-@node The \set command
+@node The set command
@subsection The @code{\set} command
@cindex properties
-@node The \override command
+@node The override command
@subsection The @code{\override} command
Commands which change output generally look like
properties. To tweak those, use commands in the form
@example
-\override Stem #'details #'beamed-lengths = #'(4 4 3)
+\override Stem #'(details beamed-lengths) = #'(4 4 3)
@end example
@cindex internal documentation
and the program reference.
-@node \set versus \override
+@node The tweak command
+@subsection The @code{\tweak} command
+
+@funindex \tweak
+@cindex tweaking
+
+In some cases, it is possible to take a short-cut for tuning
+graphical objects. For objects that are created directly from
+an item in the input file, you can use the @code{\tweak} command.
+For example:
+
+@lilypond[relative=2,verbatim]
+< c
+ \tweak #'color #red
+ d
+ g
+ \tweak #'duration-log #1
+ a
+> 4
+-\tweak #'padding #8
+-^
+@end lilypond
+
+@cindex chord, modifying one note in
+
+But the main use of the @code{\tweak} command is to modify just
+one of a number of notation elements which start at the same musical
+moment, like the notes of a chord, or tuplet brackets which start
+at the same time.
+
+For an introduction to the syntax and uses of the tweak command
+see @rlearning{Tweaking methods}.
+
+The @code{\tweak} command sets a property in the following object
+directly, without requiring the grob name or context to be
+specified. For this to work, it is necessary for the @code{\tweak}
+command to remain immediately adjacent to the object to which it is
+to apply after the input file has been converted to a music stream.
+This is often not the case, as many additional elements are inserted
+into the music stream implicitly. For example, when a note which is
+not part of a chord is processed, Lilypond implicitly inserts a
+@code{ChordEvent} event before the note, so separating the tweak
+from the note. However, if chord symbols are placed round the
+tweak and the note, the @code{\tweak} command comes after the
+@code{ChordEvent} in the music stream, so remaining adjacent to the
+note, and able to modify it.
+
+So, this works:
+
+@lilypond[relative=2,verbatim,quote]
+<\tweak #'color #red c>4
+@end lilypond
+
+@noindent
+but this does not:
+
+@lilypond[relative=2,verbatim,quote]
+\tweak #'color #red c4
+@end lilypond
+
+When several similar items are placed at the same musical moment,
+the @code{\override} command cannot be used to modify just one of
+them -- this is where the @code{\tweak} command must be used.
+Items which may appear more than once at the same musical moment
+include the following:
+
+@c TODO expand to include any further uses of \tweak
+@itemize
+@item note heads of notes inside a chord
+@item articulation signs on a single note
+@item ties between notes in a chord
+@item tuplet brackets starting at the same time
+@end itemize
+
+@c TODO add examples of these
+
+@noindent
+and @code{\tweak} may be used to modify any single occurrence of
+these items.
+
+Notably the @code{\tweak} command cannot be used to modify stems,
+beams or accidentals, since these are generated later by note heads,
+rather than by music elements in the input stream. Nor can a
+@code{\tweak} command be used to modify clefs or time signatures,
+since these become separated from any preceding @code{\tweak}
+command in the input stream by the automatic insertion of extra
+elements required to specify the context.
+
+But the @code{\tweak} command can be used as an alternative to
+the @code{\override} command to modify those notational elements
+that do not cause any additional implicit elements to be added
+before them in the music stream. For example, slurs may be
+modified in this way:
+
+@lilypond[verbatim,quote,relative=1]
+c-\tweak #'thickness #5 ( d e f)
+@end lilypond
+
+Also several @code{\tweak} commands may be placed before a
+notational element -- all affect it:
+
+@lilypond[verbatim,quote,relative=1]
+c
+-\tweak #'style #'dashed-line
+-\tweak #'dash-fraction #0.2
+-\tweak #'thickness #3
+-\tweak #'color #red
+ \glissando
+f'
+@end lilypond
+
+The music stream which is generated from a section of an input file,
+including any automatically inserted elements, may be examined,
+see @ref{Displaying music expressions}. This may be helpful in
+determining what may be modified by a @code{\tweak} command.
+
+
+@seealso
+Learning Manual:
+@rlearning{Tweaking methods}.
+
+Notation Reference:
+@ref{Displaying music expressions}.
+
+
+@knownissues
+
+@cindex tweaks in a variable
+The @code{\tweak} command cannot be used inside a variable.
+
+@cindex tweaks in lyrics
+The @code{\tweak} commands cannot be used in @code{\lyricmode}.
+
+@cindex tweaking control points
+@cindex control points, tweaking
+
+The @code{\tweak} command cannot be used to modify the control
+points of just one of several ties in a chord, other than the first
+one encountered in the input file.
+
+@node set versus override
@subsection @code{\set} vs. @code{\override}
We have seen two methods of changing properties: @code{\set} and
property (modified with @code{\set}) was created.
-@node Objects connected to the input
-@subsection Objects connected to the input
-
-TODO: can't use \tweak in a variable
-
-@funindex \tweak
-
-In some cases, it is possible to take a short-cut for tuning graphical
-objects. For objects that result directly from a piece of the input,
-you can use the @code{\tweak} function, for example
-
-@lilypond[relative=2,fragment,verbatim,ragged-right]
-<
- c
- \tweak #'color #red d
- g
- \tweak #'duration-log #1 a
->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
* Input modes::
* Direction and placement::
* Distances and measurements::
+* Staff symbol properties::
* Spanners::
+* Visibility of objects::
+* Line styles::
+* Rotating objects::
@end menu
@node Input modes
@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.
+@strong{Context layout order}
-@c TODO Add example ?
+Contexts are normally 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. When
+contexts are nested, the outer context will exclude inner contexts
+which are not included in its @qq{accepts} list; excluded contexts
+will be repositioned below the outer context.
-The default order in which contexts are laid out can be changed,
-see @ref{Aligning contexts}
+The default order in which contexts are laid out and the
+@qq{accepts} list can be changed, see @ref{Aligning contexts}.
@strong{Articulation direction indicators}
@node Distances and measurements
@subsection Distances and measurements
-DISCUSS after working on other sections.
+@cindex distances, absolute
+@cindex distances, scaled
+
+@funindex \mm
+@funindex \cm
+@funindex \in
+@funindex \pt
+
+Distances in LilyPond are of two types: absolute and scaled.
+
+Absolute distances are used for specifying margins, indents, and
+other page layout details, and are by default specified in
+millimeters. Distances may be specified in other units by
+following the quantity by @code{\mm}, @code{\cm},
+@code{\in}@tie{}(inches), or @code{\pt}@tie{}(points, 1/72.27
+of an inch). Page layout distances can also be specified in
+scalable units (see the following paragraph) by appending
+@code{\staff-space} to the quantity.
+Page layout is described in detail in @ref{Page formatting}.
+
+Scaled distances are always specified in units of the staff-space
+or, rarely, the half staff-space. The staff-space is the distance
+between two adjacent staff lines. The default value can be changed
+globally by setting the global staff size, or it can be overridden
+locally by changing the @code{staff-space} property of
+@code{StaffSymbol}. Scaled distances automatically scale with any
+change to the either the global staff size or the
+@code{staff-space} property of @code{StaffSymbol}, but fonts scale
+automatically only with changes to the global staff size.
+The global staff size thus enables the overall size of a rendered
+score to be easily varied. For the methods of setting the global
+staff size see @ref{Setting the staff size}.
+
+@funindex magstep
+
+If just a section of a score needs to be rendered to a different
+scale, for example an ossia section or a footnote, the global staff
+size cannot simply be changed as this would affect the entire score.
+In such cases the change in size is made by overriding both the
+@code{staff-space} property of @code{StaffSymbol} and the size of
+the fonts. A Scheme function, @code{magstep}, is available to
+convert from a font size change to the equivalent change in
+@code{staff-space}. For an explanation and an example of its use,
+see @rlearning{Length and thickness of objects}.
+
+
+@seealso
+Learning Manual:
+@rlearning{Length and thickness of objects}.
-TODO: staff spaces. Maybe move into tweaks?
+Notation Reference:
+@ref{Page formatting},
+@ref{Setting the staff size}.
+
+
+@node Staff symbol properties
+@subsection Staff symbol properties
+
+@cindex adjusting staff symbol
+@cindex drawing staff symbol
+@cindex staff symbol, setting of
+
+@c TODO Extend or remove this section. See also NR 1.6.2 Staff symbol
+@c Need to think of uses for these properties. Eg 'line-positions
+@c is used in a snippet to thicken centre line.
+@c If retained, add @ref to here in 1.6.2 -td
+
+The vertical position of staff lines and the number of staff lines
+can be defined at the same time. As the following example shows,
+note positions are not influenced by the staff line positions.
+
+@warning{The @code{'line-positions} property overrides the
+@code{'line-count} property. The number of staff lines is
+implicitly defined by the number of elements in the list of values
+for @code{'line-positions}.}
+
+@lilypond[verbatim,quote,relative=1]
+\new Staff \with {
+ \override StaffSymbol #'line-positions = #'(7 3 0 -4 -6 -7)
+}
+{ a4 e' f b | d1 }
+@end lilypond
+
+The width of a staff can be modified. The units are staff
+spaces. The spacing of objects inside the staff is not affected by
+this setting.
+
+@lilypond[verbatim,quote,relative=1]
+\new Staff \with {
+ \override StaffSymbol #'width = #23
+}
+{ a4 e' f b | d1 }
+@end lilypond
@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.
+several bars. Examples are slurs, beams, tuplet brackets, volta
+repeat brackets, crescendi, trills, and glissandi. Such objects
+are collectively 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
+All spanners support the @code{spanner-interface}. A few, esentially
+those that draw a straight line between the two objects, support in
+addition the @code{line-spanner-interface}.
-@menu
-* Controlling visibility of objects::
-* Line styles::
-* Rotating objects::
-* Aligning objects::
-@end menu
+@unnumberedsubsubsec Using the @code{spanner-interface}
+
+This interface provides two properties that apply to several spanners.
+
+@strong{@i{The @code{minimum-length} property}}
+
+The minimum length of the spanner is specified by the
+@code{minimum-length} property. Increasing this usually has the
+necessary effect of increasing the spacing of the notes between the
+two end points. However, this override has no effect on
+many spanners, as their length is determined by other considerations.
+A few examples where it is effective are shown below.
+
+@ignore
+Works for:
+ Tie
+ MultiMeasureRest
+ Hairpin
+ Slur
+ PhrasingSlur
+
+Works as long as callback is made:
+ Glissando
+ Beam
+
+Works not at all for:
+ LyricSpace
+ LyricHyphen
+ LyricExtender
+ TextSpanner
+ System
+
+@end ignore
+
+@lilypond[verbatim,quote,relative=2]
+a~a
+a
+% increase the length of the tie
+-\tweak #'minimum-length #5
+~a
+@end lilypond
+
+@lilypond[verbatim,quote,relative=2]
+a1
+\compressFullBarRests
+R1*23
+% increase the length of the rest bar
+\once \override MultiMeasureRest #'minimum-length = #20
+R1*23
+a1
+@end lilypond
+
+@lilypond[verbatim,quote,relative=2]
+a \< a a a \!
+% increase the length of the hairpin
+\override Hairpin #'minimum-length = #20
+a \< a a a \!
+@end lilypond
+
+This override can also be used to increase the length of slurs and
+phrasing slurs:
+
+@lilypond[verbatim,quote,relative=2]
+a( a)
+a
+-\tweak #'minimum-length #5
+( a)
+
+a\( a\)
+a
+-\tweak #'minimum-length #5
+\( a\)
+@end lilypond
+
+For some layout objects, the @code{minimum-length} property becomes
+effective only if the @code{set-spacing-rods} procedure is called
+explicitly. To do this, the @code{springs-and-rods} property should
+be set to @code{ly:spanner::set-spacing-rods}. For example,
+the minimum length of a glissando has no effect unless the
+@code{springs-and-rods} property is set:
+
+@lilypond[verbatim,quote,relative=1]
+% default
+e \glissando c'
+
+% not effective alone
+\once \override Glissando #'minimum-length = #20
+e, \glissando c'
+
+% effective only when both overrides are present
+\once \override Glissando #'minimum-length = #20
+\once \override Glissando #'springs-and-rods = #ly:spanner::set-spacing-rods
+e, \glissando c'
+@end lilypond
+
+The same is true of the @code{Beam} object:
+
+@lilypond[verbatim,quote,relative=1]
+% not effective alone
+\once \override Beam #'minimum-length = #20
+e8 e e e
+
+% effective only when both overrides are present
+\once \override Beam #'minimum-length = #20
+\once \override Beam #'springs-and-rods = #ly:spanner::set-spacing-rods
+e8 e e e
+@end lilypond
+
+@strong{@i{The @code{to-barline} property}}
+
+The second useful property of the @code{spanner-interface} is
+@code{to-barline}. By default this is true, causing hairpins and
+other spanners which are terminated on the first note of a measure to
+end instead on the immediately preceding bar line. If set to false,
+the spanner will extend beyond the bar line and end on the note
+itself:
+
+@lilypond[verbatim,quote,relative=2]
+a \< a a a a \! a a a \break
+\override Hairpin #'to-barline = ##f
+a \< a a a a \! a a a
+@end lilypond
+
+This property is not effective for all spanners. For example,
+seting it to @code{#t} has no effect on slurs or phrasing slurs
+or on other spanners for which terminating on the bar line would
+not be meaningful.
+
+@unnumberedsubsubsec Using the @code{line-spanner-interface}
+
+Objects which support the @code{line-spanner-interface} include
+
+@itemize
+@item @code{DynamicTextSpanner}
+@item @code{Glissando}
+@item @code{TextSpanner}
+@item @code{TrillSpanner}
+@item @code{VoiceFollower}
+@end itemize
+
+The routine responsible for drawing the stencils for these spanners is
+@code{ly:line-interface::print}. This routine determines the
+exact location of the two end points and draws a line
+between them, in the style requested. The locations of the two
+end points of the spanner are computed on-the-fly, but it is
+possible to override their Y-coordinates. The
+properties which need to be specified are nested
+two levels down within the property hierarchy, but the syntax of
+the @code{\override} command is quite simple:
+
+@lilypond[relative=2,quote,verbatim]
+e2 \glissando b
+\once \override Glissando #'(bound-details left Y) = #3
+\once \override Glissando #'(bound-details right Y) = #-2
+e2 \glissando b
+@end lilypond
+
+The units for the @code{Y} property are @code{staff-space}s,
+with the center line of the staff being the zero point.
+For the glissando, this is the value for @code{Y} at the
+X-coordinate corresponding to the center point of each note head,
+if the line is imagined to be extended to there.
+
+If @code{Y} is not set, the value is computed from the vertical
+position of the corresponding attachment point of the spanner.
+
+In case of a line break, the values for the end points are
+specified by the @code{left-broken} and @code{right-broken}
+sub-lists of @code{bound-details}. 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
+
+
+A number of further properties of the @code{left} and
+@code{right} sub-lists of the @code{bound-details} property
+may be modified in the same way as @code{Y}:
+
+@table @code
+@item Y
+This sets the Y-coordinate of the end point, in @code{staff-space}s
+offset from the staff center line. By default, it is the center of
+the bound object, so a glissando points to the vertical center of
+the note head.
+
+For horizontal spanners, such as text spanners and trill spanners,
+it is hardcoded to 0.
+
+@item attach-dir
+This determines where the line starts and ends in the 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 X-coordinate of the end point. It is usually
+computed on the fly, and overriding it has little useful effect.
+
+@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 that @code{text} be used instead.
+
+@item text
+This is a markup that is evaluated to yield the stencil. It is used
+to put @i{cresc.}, @i{tr} and other text 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 one of these, the stencil is simply put at the
+end-point, centered on the line, 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 vertically
+relative to the end point of the line:
+
+@lilypond[relative=1,fragment,verbatim]
+\override TextSpanner
+ #'(bound-details left stencil-align-dir-y) = #-2
+\override TextSpanner
+ #'(bound-details right stencil-align-dir-y) = #UP
+
+\override TextSpanner
+ #'(bound-details left text) = #"ggg"
+\override TextSpanner
+ #'(bound-details right text) = #"hhh"
+c4^\startTextSpan c c c \stopTextSpan
+@end lilypond
-@node Controlling visibility of objects
-@subsection Controlling visibility of objects
+Note that negative values move the text @emph{up}, contrary to the
+effect that might be expected, as a value of @code{-1} or
+@code{DOWN} means align the @emph{bottom} edge of the text with
+the spanner line. A value of @code{1} or @code{UP} aligns
+the top edge of the text with the spanner line.
+
+@item arrow
+Setting this sub-property to @code{#t} produces 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
+
+The music function @code{\endSpanners} terminates the spanner
+which starts on the immediately following note prematurely. It
+is terminated after exactly one note, or at the following bar line
+if @code{to-barline} is true and a bar line occurs before the next
+note.
+
+@lilypond[verbatim,quote,ragged-right,relative=2,fragment]
+\endSpanners
+c2 \startTextSpan c2 c2
+\endSpanners
+c2 \< c2 c2
+@end lilypond
+
+When using @code{\endSpanners} it is not necessary to close
+\startTextSpan with \stopTextSpan, nor is it necessary to close
+hairpins with @code{\!}.
+
+
+@seealso
+Internals Reference: @rinternals{TextSpanner},
+@rinternals{Glissando}, @rinternals{VoiceFollower},
+@rinternals{TrillSpanner},
+@rinternals{line-spanner-interface}.
+
+
+@node Visibility of objects
+@subsection Visibility of objects
@cindex objects, visibility of
@cindex grobs, visibility of
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
+Alternatively, these 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 .1 .1 .1
-@c TODO check these more carefully
+@multitable {@code{begin-of-line-invisible}} {@code{'#(#t #t #t)}} {yes} {yes} {yes}
@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{all-visible} @tab @code{'#(#t #t #t)} @tab yes @tab yes @tab yes
@item @code{begin-of-line-visible} @tab @code{'#(#f #f #t)} @tab no @tab no @tab yes
+@item @code{center-visible} @tab @code{'#(#f #t #f)} @tab no @tab yes @tab no
@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
+@item @code{end-of-line-invisible} @tab @code{'#(#f #t #t)} @tab no @tab yes @tab yes
+@item @code{all-invisible} @tab @code{'#(#f #f #f)} @tab no @tab no @tab no
@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
@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.
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.
+exact location of the two @i{span points} and draws a line
+between them, in the style requested.
-Here is an example of the different line styles available, and how
-to tune them.
+Here is an example showing the different line styles available,
+and how to tune them.
@lilypond[relative=2,ragged-right,verbatim,fragment]
d2 \glissando d'2
d,2 \glissando d'2
@end lilypond
-The information that determines the end-points is computed
+The locations of the end-points of the spanner are computed
on-the-fly for every graphic object, but it is possible to
-override these.
+override these:
+@c FIXME Complete
@lilypond[relative=2,ragged-right,verbatim,fragment]
e2 \glissando f
-\once \override Glissando #'bound-details #'right #'Y = #-2
+\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}.
+The value for @code{Y} is set to @code{-2} for the right end
+point. The left side may be similarly adjusted by specifying
+@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}.
+position of the left and right attachment points of the spanner.
+Other adjustments of spanners are possible, for details, see
+@ref{Spanners}.
@node Rotating objects
@subsection Rotating objects
fis^\markup { \rotate #30 "an F-Sharp" }
@end lilypond
-
-@node Aligning objects
-@subsection Aligning objects
-
-@c FIXME Write this section
-
-
@node Advanced tweaks
@section Advanced tweaks
+This section discusses various approaches to fine tuning the
+appearance of the printed score.
+
@menu
+* Aligning objects::
* Vertical grouping of grobs::
-* Modifying ends of spanners::
* Modifying stencils::
* Modifying shapes::
@end menu
+@seealso
+Learning Manual:
+@rlearning{Tweaking output},
+@rlearning{Other sources of information}.
+
+Notation Reference:
+@ref{Explaining the Internals Reference},
+@ref{Modifying properties},
+@ref{Interfaces for programmers}.
+
+Installed Files:
+@file{scm/@/define@/-grobs@/.scm}.
+
+Snippets:
+@rlsr{Tweaks and overrides}.
+
+Internals Reference:
+@rinternals{All layout objects}.
+
+
+@node Aligning objects
+@subsection Aligning objects
+
+Graphical objects which support the @code{self-alignment-interface} and/or
+the @code{side-position-interface} can be
+aligned to a previously placed object in a variety of ways. For a list of these objects, see
+@rinternals{self-alignment-interface} and @rinternals{side-position-interface}.
+
+All graphical objects have a reference point, a horizontal extent and a
+vertical extent. The horizontal extent is a pair of numbers
+giving the displacements from the reference point of the left and
+right edges, displacements to the left being negative. The
+vertical extent is a pair of numbers giving the displacement from
+the reference point to the bottom and top edges, displacements down
+being negative.
+
+An object's position on a staff is given by the values of the
+@code{X-offset} and @code{Y-offset} properties. The value of
+@code{X-offset} gives the displacement from the x coordinate of
+the reference point of the parent object, and the value of
+@code{Y-offset} gives the displacement from the center line of the
+staff. The values of @code{X-offset} and
+@code{Y-offset} may be set directly or may be set to be calculated
+by procedures in order to achieve alignment with the parent object
+in several ways.
+
+@warning{Many objects have special positioning considerations which
+cause any setting of @code{X-offset} or @code{Y-offset} to be
+ignored or modified, even though the object supports the
+@code{self-alignment-interface}.}
+
+For example, an accidental can be repositioned
+vertically by setting @code{Y-offset} but any changes to
+@code{X-offset} have no effect.
+
+Rehearsal marks may be aligned with
+breakable objects such as bar lines, clef symbols, time signature
+symbols and key signatures. There are special properties to be
+found in the @code{break-aligned-interface} for positioning rehearsal
+marks on such objects.
+
+@menu
+* Setting @code{X-offset} and @code{Y-offset} directly::
+* Using the @code{side-position-interface}::
+* Using the @code{self-alignment-interface}::
+* Using the @code{break-alignable-interface}::
+@end menu
+
+@node Setting @code{X-offset} and @code{Y-offset} directly
+@unnumberedsubsubsec Setting @code{X-offset} and @code{Y-offset} directly
+
+Numerical values may be given to the @code{X-offset} and @code{Y-offset}
+properties of many objects. The following example shows three
+notes with the default fingering position and the positions with @code{X-offset}
+and @code{Y-offset} modified.
+
+@lilypond[verbatim,quote,relative=2]
+a-3
+a
+-\tweak #'X-offset #0
+-\tweak #'Y-offset #0
+-3
+a
+-\tweak #'X-offset #-1
+-\tweak #'Y-offset #1
+-3
+@end lilypond
+
+@c TODO write more
+
+@node Using the @code{side-position-interface}
+@unnumberedsubsubsec Using the @code{side-position-interface}
+
+An object which supports the @code{side-position-interface} can be
+placed next to its parent object so that
+the specified edges of the two objects touch. The object may be
+placed above, below, to the right or to the left of the parent.
+The parent cannot be specified; it is determined by the order of
+elements in the input stream. Most objects have the associated
+note head as their parent.
+
+The values of the @code{side-axis} and @code{direction} properties
+determine where the object is to be placed, as follows:
+
+@c TODO add an example of each to the table
+
+@multitable @columnfractions .3 .3 .3
+@headitem @code{side-axis} @tab @code{direction} @tab
+@headitem property @tab property @tab Placement
+
+@item @code{0} @tab @code{-1} @tab left
+@item @code{0} @tab @code{1} @tab right
+@item @code{1} @tab @code{-1} @tab below
+@item @code{1} @tab @code{1} @tab above
+
+@end multitable
+
+When @code{side-axis} is @code{0}, @code{X-offset} should be set to
+the procedure @code{ly:side-position-interface::x-aligned-side}.
+This procedure will return the correct value of @code{X-offset} to
+place the object to the left or right side of the parent according
+to value of @code{direction}.
+
+When @code{side-axis} is @code{1}, @code{Y-offset} should be set to
+the procedure @code{ly:side-position-interface::y-aligned-side}.
+This procedure will return the correct value of @code{Y-offset} to
+place the object to the top or bottom of the parent according
+to value of @code{direction}.
+
+@c TODO Add examples
+
+@node Using the @code{self-alignment-interface}
+@unnumberedsubsubsec Using the @code{self-alignment-interface}
+
+@emph{Self-aligning objects horizontally}
+
+The horizontal alignment of an object which supports the
+@code{self-alignment-interface} is controlled by the value of
+the @code{self-alignment-X} property, provided the object's
+@code{X-offset} property is set to
+@code{ly:self-alignment-interface::x-aligned-on-self}.
+@code{self-alignment-X} may be given any
+real value, in units of half the total X extent of the
+object. Negative values move the object to the right, positive
+to the left. A value of @code{0} centers the object on the
+reference point of its parent, a value of @code{-1} aligns the
+left edge of the object on the reference point of its parent,
+and a value of @code{1} aligns the right edge of the object on the
+reference point of its parent. The symbols @code{LEFT},
+@code{CENTER} and @code{RIGHT} may be used instead of the values
+@code{-1, 0, 1} respectively.
+
+Normally the @code{\override} command would be used to modify the
+value of @code{self-alignment-X}, but the @code{\tweak} command
+can be used to separately align several annotations on a single
+note:
+
+@lilypond[quote,verbatim,relative=1]
+a'
+-\tweak #'self-alignment-X #-1
+^"left-aligned"
+-\tweak #'self-alignment-X #0
+^"center-aligned"
+-\tweak #'self-alignment-X #RIGHT
+^"right-aligned"
+-\tweak #'self-alignment-X #-2.5
+^"aligned further to the right"
+@end lilypond
+
+@emph{Self-aligning objects vertically}
+
+Objects may be aligned vertically in an analogous way to aligning
+them horizontally if the @code{Y-offset} property is set to
+@code{ly:self-alignment-interface::y-aligned-on-self}. However,
+other mechanisms are often involved in vertical alignment: the
+value of @code{Y-offset} is just one variable taken into account.
+This may make adjusting the value of some objects tricky.
+The units are just half the vertical extent of the object, which
+is usually quite small, so quite large numbers may be required.
+A value of @code{-1} aligns the lower edge of the object with
+the reference point of the parent object, a value of @code{0}
+aligns the center of the object with the reference point of the
+parent, and a value of @code{1} aligns the top edge of the object
+with the reference point of the parent. The symbols @code{DOWN},
+@code{CENTER}, @code{UP} may be substituted for @code{-1, 0, 1}
+respectively.
+
+@emph{Self-aligning objects in both directions}
+
+By setting both @code{X-offset} and @code{Y-offset}, an object may
+be aligned in both directions simultaneously.
+
+The following example shows how to adjust a fingering mark so
+that it nestles close to the note head.
+
+@lilypond[quote,verbatim,relative=2]
+a
+-\tweak #'self-alignment-X #0.5 % move horizontally left
+-\tweak #'Y-offset #ly:self-alignment-interface::y-aligned-on-self
+-\tweak #'self-alignment-Y #-1 % move vertically up
+-3 % third finger
+@end lilypond
+
+@ignore
+@unnumberedsubsubsec Using the @code{aligned-on-parent} procedures
+
+@c Cannot document as they do not seem to operate consistently on all objects -td
+@c TODO investigate further
+
+The @code{aligned-on-parent} procedures are used in the same way
+as the @code{aligned-on-self} procedures, they difference being
+that they permit an object to be aligned with the @emph{edges} of
+the parent rather than the parent's reference point. The following
+example shows the difference:
+
+@c TODO Add example
+
+@lilypond[verbatim,quote]
+@end lilypond
+
+@end ignore
+
+@ignore
+@unnumberedsubsubsec Using the @code{centered-on-parent} procedures
+
+@c Cannot document as they do not seem to operate consistently on all objects -td
+@c TODO investigate further
+
+@end ignore
+
+@c TODO The align-interface, BassFigureAlignment and VerticalAlignment
+
+@node Using the @code{break-alignable-interface}
+@unnumberedsubsubsec Using the @code{break-alignable-interface}
+
+@cindex align to objects
+@cindex break-align-symbols
+
+Rehearsal marks and bar numbers may be aligned with notation
+objects other than bar lines. These objects include @code{ambitus},
+@code{breathing-sign}, @code{clef}, @code{custos}, @code{staff-bar},
+@code{left-edge}, @code{key-cancellation}, @code{key-signature}, and
+@code{time-signature}.
+
+By default, rehearsal marks and bar numbers will be horizontally
+centered above the object:
+
+@lilypond[verbatim,quote,relative=1]
+e1
+% the RehearsalMark will be centered above the Clef
+\override Score.RehearsalMark #'break-align-symbols = #'(clef)
+\key a \major
+\clef treble
+\mark "↓"
+e
+% the RehearsalMark will be centered above the TimeSignature
+\override Score.RehearsalMark #'break-align-symbols = #'(time-signature)
+\key a \major
+\clef treble
+\time 3/4
+\mark "↓"
+e2.
+@end lilypond
+
+A list of possible target alignment objects may be specified. If
+some of the objects are invisible at that point due to the setting
+of @code{break-visibility} or the explicit visibility settings for
+keys and clefs, the rehearsal mark or bar number is aligned to the
+first object in the list which is visible. If no objects in the
+list are visible the object is aligned to the bar line. If the bar
+line is invisible the object is aligned to the place where the bar
+line would be.
+
+@lilypond[verbatim,quote,relative=1]
+e1
+% the RehearsalMark will be centered above the Key Signature
+\override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
+\key a \major
+\clef treble
+\mark "↓"
+e
+% the RehearsalMark will be centered above the Clef
+\set Staff.explicitKeySignatureVisibility = #all-invisible
+\override Score.RehearsalMark #'break-align-symbols = #'(key-signature clef)
+\key a \minor
+\clef bass
+\mark "↓"
+e,
+@end lilypond
+
+The alignment of the rehearsal mark relative to the notation object
+can be changed, as shown in the following example. In a score with
+multiple staves, this setting should be done for all the staves.
+
+@lilypond[verbatim,quote,relative=1]
+% The RehearsalMark will be centered above the KeySignature
+\override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
+\key a \major
+\clef treble
+\time 4/4
+\mark "↓"
+e1
+% The RehearsalMark will be aligned with the left edge of the KeySignature
+\once \override Score.KeySignature #'break-align-anchor-alignment = #LEFT
+\mark "↓"
+\key a \major
+e
+% The RehearsalMark will be aligned with the right edge of the KeySignature
+\once \override Score.KeySignature #'break-align-anchor-alignment = #RIGHT
+\key a \major
+\mark "↓"
+e
+@end lilypond
+
+The rehearsal mark can also be offset to the right or left of the left edge
+by an arbitrary amount. The units are staff-spaces:
+
+@lilypond[verbatim,quote,relative=1]
+% The RehearsalMark will be aligned with the left edge of the KeySignature
+% and then shifted right by 3.5 staff-spaces
+\override Score.RehearsalMark #'break-align-symbols = #'(key-signature)
+\once \override Score.KeySignature #'break-align-anchor = #3.5
+\key a \major
+\mark "↓"
+e
+% The RehearsalMark will be aligned with the left edge of the KeySignature
+% and then shifted left by 2 staff-spaces
+\once \override Score.KeySignature #'break-align-anchor = #-2
+\key a \major
+\mark "↓"
+e
+@end lilypond
@node Vertical grouping of grobs
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
+All layout objects have a @code{stencil} property which is part of
+the @code{grob-interface}. By default, this property is usually
+set to a function specific to the object that is tailor-made to
+render the symbol which represents it in the output. For example,
+the standard setting for the @code{stencil} property of the
+@code{MultiMeasureRest} object is @code{ly:multi-measure-rest::print}.
+
+The standard symbol for any object can be replaced by modifying the
+@code{stencil} property to reference a different, specially-written,
+procedure. This requires a high level of knowledge of the internal
+workings of LilyPond, but there is an easier way which can often
+produce adequate results.
+
+This is to set the @code{stencil} property to the procedure which
+prints text -- @code{ly:text-interface::print} -- and to add a
+@code{text} property to the object which is set to contain the
+markup text which produces the required symbol. Due to the
+flexibility of markup, much can be achieved -- see in particular
+@ref{Graphic notation inside markup}.
+
+The following example demonstrates this by changing the note head
+symbol to a cross within a circle.
+
+@lilypond[verbatim,quote]
+XinO = {
+ \once \override NoteHead #'stencil = #ly:text-interface::print
+ \once \override NoteHead #'text = \markup {
+ \combine
+ \halign #-0.7 \draw-circle #0.85 #0.2 ##f
+ \musicglyph #"noteheads.s2cross"
+ }
+}
+\relative c'' {
+ a a \XinO a a
+}
+@end lilypond
+
+Any of the glyphs in the feta Font can be supplied to the
+@code{\musicglyph} markup command -- see @ref{The Feta font}.
+
+@c TODO Add inserting eps files or ref to later
+
+@c TODO Add inserting Postscript or ref to later
+
+
+@seealso
+Notation Reference:
+@ref{Graphic notation inside markup},
+@ref{Formatting text},
+@ref{Text markup commands},
+@ref{The Feta font}.
+
@node Modifying shapes
@subsection Modifying shapes
@node Modifying ties and slurs
@unnumberedsubsubsec Modifying ties and slurs
-Ties, slurs and phrasing slurs are drawn as third-order Bézier
+Ties, slurs and phrasing slurs are drawn as third-order Bézier
curves. If the shape of the tie or slur which is calculated
automatically is not optimum, the shape may be modified manually by
explicitly specifying the four control points required to define
-a third-order Bézier curve.
+a third-order Bézier curve.
-Third-order or cubic Bézier curves are defined by four control
+Third-order or cubic Bézier curves are defined by four control
points. The first and fourth control points are precisely the
starting and ending points of the curve. The intermediate two
control points define the shape. Animations showing how the curve
One way of improving this tie is to manually modify its control
points, as follows.
-The coordinates of the Bézier control points are specified in units
+The coordinates of the Bézier control points are specified in units
of staff-spaces. The X@tie{}coordinate is relative to the reference
point of the note to which the tie or slur is attached, and the
Y@tie{}coordinate is relative to the staff center line. The
values are then found by trial and error.
It is useful to remember that a symmetric curve requires symmetric
-control points, and that Bézier curves have the useful property that
+control points, and that Bézier curves have the useful property that
transformations of the curve such as translation, rotation and
scaling can be achieved by applying the same transformation to the
curve's control points.
-@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]
-
-
projects / lilypond.git / blobdiff