This chapter discusses how to modify output. LilyPond is extremely
configurable; virtually every fragment of output may be changed.
-NB: This chapter is still under development and this version is
-somewhat experimental; nothing is fixed. Don't translate yet!
-
-
@menu
* Tweaking basics::
* The Internals Reference manual::
-* Common tweaks::
-* TODO other name::
+* Appearance of objects::
+* Placement of objects::
+* Collisions of objects::
+* Further tweaking::
@end menu
@node Tweaking basics
@section Tweaking basics
+@menu
+* Introduction to tweaks::
+* Objects and interfaces::
+* Naming conventions of objects and properties::
+* Tweaking methods::
+@end menu
+
+@node Introduction to tweaks
+@subsection Introduction to tweaks
+
@q{Tweaking} is a LilyPond term for the various methods available
to the user for modifying the actions taken during interpretation
of the input file and modifying the appearance of the printed
output. Some tweaks are very easy to use; others are more
complex. But taken together the methods available for tweaking
-permit almost any desired appearance of the printed music to be achieved.
+permit almost any desired appearance of the printed music to be
+achieved.
In this section we cover the basic concepts required to understand
-tweaking. Later we give a variety of potted commands which can
+tweaking. Later we give a variety of ready-made commands which can
simply be copied to obtain the same effect in your own scores, and
at the same time we show how these commands may be constructed so
that you may learn how to develop your own tweaks.
Before starting on this Chapter you may wish to review the section
-@ref{Contexts and engravers}, as Contexts, Engravers and the
+@ref{Contexts and engravers}, as Contexts, Engravers, and the
Properties contained within them are fundamental to understanding
and constructing Tweaks.
-@menu
-* Objects and interfaces::
-* Naming conventions of objects and properties::
-* Tweaking methods::
-@end menu
-
@node Objects and interfaces
@subsection Objects and interfaces
properties associated with that particular staff, for example, its
name and its key signature, together with details of the engravers
which have been assigned to operate within that staff's context.
-Similarly, there are @code{Voice} objects, @code{Score} objects,
-@code{Lyric} objects, and objects to represent barlines,
-noteheads, ties, dynamics, etc, each with their own set of
-properties.
+Similarly, there are objects to hold the properties of all other
+contexts, such as @code{Voice} objects, @code{Score} objects,
+@code{Lyrics} objects, as well as objects to represent all
+notational elements such as bar lines,
+note heads, ties, dynamics, etc. Every object has its own set of
+property values.
Some types of object are given special names. Objects which
represent items of notation on the printed output such as
-noteheads, stems, slurs, ties, fingering, clefs, etc are called
+ note heads, stems, slurs, ties, fingering, clefs, etc are called
@q{Layout objects}, often known as @q{Graphical Objects}, or
@q{Grobs} for short. These are still objects in the generic sense
above, and so they too all have properties associated with them,
We met some object naming conventions previously, in
@ref{Contexts and engravers}. Here for reference is a list
-of the most common object types together with the conventions
-for naming them and a couple of examples of some real names.
+of the most common object and property types together with
+the conventions for naming them and a couple of examples of
+some real names. We have used A to stand for any capitalised
+alphabetic character and aaa to stand for any number of
+lower-case alphabetic characters. Other characters are used
+verbatim.
@multitable @columnfractions .33 .33 .33
-@headitem Object type
+@headitem Object/property type
@tab Naming convention
@tab Example
-@item Contexts, Layout Objects
+@item Contexts
@tab Aaaa or AaaaAaaaAaaa
- @tab Staff, GrandStaff,
+ @tab Staff, GrandStaff
+@item Layout Objects
+ @tab Aaaa or AaaaAaaaAaaa
+ @tab Slur, NoteHead
@item Engravers
@tab Aaaa_aaa_engraver
@tab Clef_engraver, Note_heads_engraver
We have already met the commands @code{\set} and @code{\with},
used to change the properties of @strong{contexts} and to remove
-and add
-engravers, in @ref{Modifying context properties} and @ref{Adding
+and add @strong{engravers}, in
+@ref{Modifying context properties} and @ref{Adding
and removing engravers}. We now must meet one more command.
The command to change the properties of @strong{layout objects} is
@emph{layout_object}, which is a member of the @emph{context}
context, to the value @emph{value}.
+The @emph{context} can be omitted (and usually is) when the
+required context is unambiguously implied and is one of lowest
+level contexts, i.e., @code{Voice}, @code{ChordNames} or
+@code{Lyrics}, and we shall omit it in many of the following
+examples. We shall see later when it must be specified.
+
For now, don't worry about the @code{#'}, which must precede the
layout property, and the @code{#}, which must precede the value.
These must always be present in exactly this form. This is the
\revert @emph{context}.@emph{layout_object} #'@emph{layout_property}
@end example
+Again, just like @emph{context} in the @code{\override} command,
+@emph{context} is often not needed. It will be omitted
+in many of the following examples.
+
There is another form of the override command,
-@code{\overrideProperty}, which is occasionally required.
+@code{\overrideProperty}, which is occasionally required.
We mention it here for completeness, but for details see
@ruser{Difficult tweaks}.
+@c Maybe explain in a later iteration -td
The final tweaking command which is available is @code{\tweak}.
-It is not really a new command but a shorthand for an
-@code{\override} command which may be used in a few special
-circumstances. Again, we shall not discuss or
-use it here. You may find the details in
+This should be used to change the properties of objects which
+occur at the same musical moment, such as the notes within a
+chord. Using @code{\override} would affect all the notes
+within a chord, whereas @code{\tweak} affects just the following
+item in the input stream. You may find the details in
@ruser{Objects connected to the input}.
@node The Internals Reference manual
@menu
* Properties of layout objects::
* Properties found in interfaces::
+* Types of properties::
@end menu
@node Properties of layout objects
@cindex layout objects, properties of
Suppose you have a slur in a score which, to your mind,
-appears too thin and you'd like to draw it a little thicker.
+appears too thin and you'd like to draw it a little heavier.
How do you go about doing this? You know from the statements
earlier about the flexibility of LilyPond that such a thing
should be possible, and you would probably guess that an
@code{\override} command would be needed. But is there a
-thickness property for a slur, and if there is, how might it
+heaviness property for a slur, and if there is, how might it
be modified? This is where the Internals Reference manual
comes in. It contains all the information you might need to
construct this and all other @code{\override} commands.
This is a @strong{reference} document, which means there is
little or no explanation contained within it: its purpose is
to present information precisely and concisely. This
-might mean it looks daunting at first sight. Don't worry!
+means it might look daunting at first sight. Don't worry!
The guidance and explanation presented here will enable you
to extract the information from the Internals Reference for
yourself with just a little practice.
@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
{
\time 6/8
- { r4 b8 b[( g]) g | g[( e]) e d[( f]) a | a g }
- \addlyrics { The man who feels love's sweet e -- mo -- tion }
+ {
+ r4 b8 b[( g]) g |
+ g[( e]) e d[( f]) a |
+ a g
+ }
+ \addlyrics {
+ The man who feels love's sweet e -- mo -- tion
+ }
}
@end lilypond
this we must look in the Internals Reference, or IR for short.
The IR for the version of LilyPond you are using may be found
-on the LilyPond website at http://lilypond.org. Go to the
+on the LilyPond website at @uref{http://lilypond.org}. Go to the
documentation page and click on the Internals Reference link.
For learning purposes you should use the standard html version,
not the @q{one big page} or the PDF. For the next few
Line thickness, generally measured in @code{line-thickness}
@end example
-This tells us first that there @emph{is} a property that
-controls thickness, that its value is a simple @emph{number},
+This looks a good bet to change the heaviness. It tells us that
+the value of @code{thickness} is a simple @emph{number},
that the default value is 1.2, and that the units are
-in another property called @code{line-thickness}. This looks
-a good bet to change the heaviness.
+in another property called @code{line-thickness}.
As we said earlier, there are few to no explanations in the IR,
but we already have enough information to try changing the
@code{thickness} and that the new value should be a number
somewhat larger than 1.2 if we are to make slurs thicker.
-But what is the Context? We could guess that slurs are in
-the Voice context, as they are clearly closely associated
-with individual lines of music, but can we be sure? To
-find out, go back to the top of the IR page describing the
-Slur, where it says @q{Slur objects are created by: Slur
-engraver}. So slurs will be created in whichever context
-the @code{Slur_engraver} is in. Follow the link to the
-@code{Slur_engraver} page. At the very bottom it tells
-us that @code{Slur_engraver} is part of five Voice contexts,
-including the standard voice context, @code{Voice}, so our
-guess was correct.
-
We can now construct the @code{\override} command by simply
-substituting the values we have found for the names. Let's
-use a very large value for the thickness at first, so we
-can be sure the command is working. We get:
+substituting the values we have found for the names, omitting
+the context. Let's use a very large value for the thickness
+at first, so we can be sure the command is working. We get:
@example
- \override Voice.Slur #'thickness = #5.0
+ \override Slur #'thickness = #5.0
@end example
Don't forget the @code{#'} preceding the
The final question is, @q{Where should this command be
placed?} While you are unsure and learning, the best
-answer is, @q{Within the music, before the first slur and
+answer is, @q{Within the music, before the first slur and
close to it.} Let's do that:
@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
{
\time 6/8
- {
+ {
% Increase thickness of all following slurs from 1.2 to 5.0
- \override Voice.Slur #'thickness = #5.0
- r4 b8 b[( g]) g | g[( e]) e d[( f]) a | a g
+ \override Slur #'thickness = #5.0
+ r4 b8 b[( g]) g |
+ g[( e]) e d[( f]) a |
+ a g
+ }
+ \addlyrics {
+ The man who feels love's sweet e -- mo -- tion
}
- \addlyrics { The man who feels love's sweet e -- mo -- tion }
}
@end lilypond
+@noindent
+and we see that the slur is indeed heavier.
+
+So this is the basic way of constructing @code{\override}
+commands. There are a few more complications that we
+shall meet in later sections, but you now know all the
+essentials required to make up your own -- but you will
+still need some practice. This is provided in the examples
+which follow.
+
+@subheading Finding the context
+@cindex context, finding
+
+But first, what if we had needed to specify the Context?
+What should it be? We could guess that slurs are in
+the Voice context, as they are clearly closely associated
+with individual lines of music, but can we be sure? To
+find out, go back to the top of the IR page describing the
+Slur, where it says @q{Slur objects are created by: Slur
+engraver}. So slurs will be created in whichever context
+the @code{Slur_engraver} is in. Follow the link to the
+@code{Slur_engraver} page. At the very bottom it tells
+us that @code{Slur_engraver} is part of five Voice contexts,
+including the standard voice context, @code{Voice}, so our
+guess was correct. And because @code{Voice} is one of the
+lowest level contexts which is implied unambiguously by
+the fact that we are entering notes, we can omit it in this
+location.
+
+@subheading Overriding once only
+
@cindex overriding once only
@cindex once override
@funindex \once
-As you can see, all the slurs are thicker. But, what if we
+As you can see, @emph{all} the slurs are thicker in the
+final example above. But what if we
wanted just the first slur to be thicker? This is achieved
with the @code{\once} command. Placed immediately before
-the @code{\override} command it causes it to affect only the
-slur on the @strong{immediately following} note. If the
-immediately following note does not have a slur the command
-has no effect. So the command must be repositioned as follows:
+the @code{\override} command it causes it to change only the
+slur which begins on the @strong{immediately following} note.
+If the
+immediately following note does not begin a slur the command
+has no effect at all -- it is not remembered until a slur
+is encountered, it is simply discarded. So the command with
+@code{\once} must be
+repositioned as follows:
@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
{
\time 6/8
- {
+ {
r4 b8
% Increase thickness of immediately following slur only
- \once \override Voice.Slur #'thickness = #5.0
- b[( g]) g | g[( e]) e d[( f]) a | a g
+ \once \override Slur #'thickness = #5.0
+ b[( g]) g |
+ g[( e]) e d[( f]) a |
+ a g
+ }
+ \addlyrics {
+ The man who feels love's sweet e -- mo -- tion
}
- \addlyrics { The man who feels love's sweet e -- mo -- tion }
}
@end lilypond
+
+@noindent
+Now only the first slur is made heavier.
+
+The @code{\once} command can also be used before @code{\set}
+and @code{\unset}, and before the command to be introduced
+in the following section -- @code{revert}.
+@subheading Reverting
+
+@cindex revert
+@cindex default properties, reverting
+@funindex \revert
+
Finally, what if we wanted just the first two slurs to be
heavier? Well, we could use two commands, each preceded by
@code{\once} placed immediately before each of the notes where
{
r4 b8
% Increase thickness of immediately following slur only
- \once \override Voice.Slur #'thickness = #5.0
+ \once \override Slur #'thickness = #5.0
b[( g]) g |
% Increase thickness of immediately following slur only
- \once \override Voice.Slur #'thickness = #5.0
- g[( e]) e d[( f]) a | a g
+ \once \override Slur #'thickness = #5.0
+ g[( e]) e d[( f]) a |
+ a g
+ }
+ \addlyrics {
+ The man who feels love's sweet e -- mo -- tion
}
- \addlyrics { The man who feels love's sweet e -- mo -- tion }
}
@end lilypond
-@cindex revert
-@funindex \revert
-
@noindent
-or we could omit the @code{\once} command and use the
+or we could omit the @code{\once} command and use the
@code{\revert} command
-to return the @code{thickness} property to its default value:
+to return the @code{thickness} property to its default value
+after the second slur:
@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
{
{
r4 b8
% Increase thickness of all following slurs from 1.2 to 5.0
- \override Voice.Slur #'thickness = #5.0
+ \override Slur #'thickness = #5.0
b[( g]) g |
g[( e])
% Revert thickness of all following slurs to default of 1.2
- \revert Voice.Slur #'thickness
- e d[( f]) a | a g
+ \revert Slur #'thickness
+ e d[( f]) a |
+ a g
+ }
+ \addlyrics {
+ The man who feels love's sweet e -- mo -- tion
}
- \addlyrics { The man who feels love's sweet e -- mo -- tion }
}
@end lilypond
That concludes our introduction to the IR, and the basic
method of tweaking. Several examples follow in the later
-sections of this Chapter, but with progressively fewer words
-of guidance and explanation.
+sections of this Chapter, partly to introduce you to some of the
+additional features of the IR, and partly to give you more
+practice in extracting information from it. These examples will
+contain progressively fewer words of guidance and explanation.
@node Properties found in interfaces
@subsection Properties found in interfaces
@cindex interface properties
@cindex properties in interfaces
-Suppose now that we wish to color a slur red. We would go
-to the properties on Slurs in the IR as described in the
-previous section, and look in vain, because there is nothing
-there that looks like it might change the color. This is
-because the color property is one that is common to all
-layout objects, so, rather than including it in every layout
+Suppose now that we wish to print the lyrics in italics. What
+form of @code{\override} command do we need to do this?
+We first look in the IR page listing @q{All layout objects}, as
+before, and look for an object that might control lyrics. We
+find @code{LyricText}, which looks right. Clicking on this shows
+the settable properties for lyric text. These include the
+@code{font-series} and @code{font-size}, but nothing that might
+give an italic shape.
+This is because the shape property is one that is common to all
+font objects, so, rather than including it in every layout
object, it is grouped together with other similar common
-properties and placed in an @strong{Interface}, the
-@code{grob-interface}. (Remember, grob is short for
-@q{graphical object}, itself another name for a layout object.)
+properties and placed in an @strong{Interface}, the
+@code{font-interface}.
So now we need to learn how to find the properties of interfaces,
and to discover what objects use these interface properties.
-Look again at the IR page which describes the Slur. At the
+Look again at the IR page which describes LyricText. At the
bottom of the page is a list of clickable (in the html versions
-of the IT) interfaces which the Slur supports. The list has
-three items: @code{spanner-interface}, @code{slur-interface}
-and @code{grob-interface}.
-
-The @code{spanner-interface} holds properties common to
-spanners -- objects which extend over several notes --
-as do Slurs.
-
-The @code{slur-interface} holds properties common to ordinary
-slurs and phrasing slurs.
-
-The @code{grob-interface} holds properties common to all
-layout objects, and it is here that you will find the
-@code{color} property, which appears as
+of the IR) interfaces which LyricText supports. The list has
+seven items, including @code{font-interface}.
+Clicking on this brings up the properties associated
+with this interface, which are also properties of all the objects
+which support it, including LyricText.
+
+Now we see all the user-settable properties which control fonts,
+including @code{font-shape(symbol)}, where @code{symbol} can be
+set to @code{upright}, @code{italics} or @code{caps}.
+
+You will notice that that @code{font-series} and @code{font-size}
+are also listed there.
+This immediately raises the question: Why are the common font
+properties @code{font-series} and @code{font-size} listed under
+@code{LyricText} as well as under the interface
+@code{font-interface} but @code{font-shape} is not? The answer
+is that @code{font-series} and @code{font-size} are changed
+from their global default values when a @code{LyricText} object
+is created, but @code{font-shape} is not. The entries in
+@code{LyricText} then tell you the values for those two
+properties which apply to @code{LyricText}. Other objects
+which support @code{font-interface} will set these
+properties diferently when they are created.
+
+Let's see if we can now construct the @code{\override} command
+to change the lyrics to italics. The object is @code{LyricText},
+the property is @code{font-shape} and the value is
+@code{italic}. As before, we'll omit the context.
+
+As an aside, although it is an important one, note that because
+the values of
+@code{font-shape} are symbols they must be introduced with a
+single apostrophe, @code{'}. That is why apostrophes
+are needed before @code{thickness} in the earlier example
+and @code{font-shape}. These are both symbols too.
+Symbols are special names which are known internally to
+LilyPond. Some of them are the names of properties,
+like @code{thickness} or @code{font-shape}, others are in
+effect special values that can be given to properties, like
+@code{italic}. Note the distinction from arbitary
+text strings, which would appear as @code{"a text string"}.
+
+Ok, so the @code{\override} command we need to print the lyrics
+in italics should be
@example
-color(list)
- The color of this grob
-@end example
-
-... to be continued
-
-@ignore
-@c The rest of this section is rubbish and will need to be rewritten -td
-
-The value then is described as a @emph{list}? Why do we need
-a list to specify a color? Well, we don't, but there are
-several ways to specify a color and some of them do need a list.
-See the Notation Reference @ruser{List of colors}. This shows
-the @q{Normal colors} and the longer list of @q{X color names}.
-The normal colors are written as a one-member list, which can
-be written simply as @code{red}. But the X color names must be
-written as a two-member list:
-
-@example
-(x11-color 'LimeGreen)
+ \override LyricText #'font-shape = #'italic
@end example
@noindent
-where the first item in the list is always @q{x11-color} to
-indicate this is a color from the longer list of X11 colors,
-and the second item is the name of the color from the list
-of X11 colors in the Notation Reference.
-
-@cindex properties as lists
-@cindex properties as text strings
-
-This introduces two new concepts.
-
-First the brackets round
-this property value are required to form the two items into
-a list, as required by the color property. Brackets would
-generate an error if placed around a @q{normal color}, though,
-because these are shorthand names known to LilyPond which
-generate the appropriate list automatically.
-
-Second, because the second
-item is a text string it needs to be introduced with a
-single apostrophe, @code{'}. This is why these apostrophes
-are needed before @code{'thickness} and @code{'color'}.
-These are both text strings too.
-
-So, putting this into practice, we can change the second
-slur to the normal color magenta and the third slur
-to the X11 color, DarkOrange, where we have made all the
-slurs thicker to show the colors better, as follows:
+and this should be placed just in front of and close to the
+lyrics which it should affect, like this:
@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
{
\time 6/8
{
- \override Voice.Slur #'thickness = #5.0
- r4 b8
- b[( g]) g |
- \once \override Voice.Slur #'color = #magenta
- g[( e]) e
- \once \override Voice.Slur #'color = #(x11-color 'DarkOrange)
- d[( f]) a | a g
+ r4 b8 b[( g]) g |
+ g[( e]) e d[( f]) a |
+ a g
+ }
+ \addlyrics {
+ \override LyricText #'font-shape = #'italic
+ The man who feels love's sweet e -- mo -- tion
}
- \addlyrics { The man who feels love's sweet e -- mo -- tion }
}
@end lilypond
-@end ignore
-
+@noindent
+and the lyrics are all printed in italics.
+
+@subheading Specifying context in lyric mode
+@cindex context, specifying in lyric mode
+
+In the case of lyrics, if you try specifying the context in the
+format given earlier the command will fail. A syllable
+entered in lyricmode is terminated by either a space,
+a newline or a digit. All other characters are included
+as part of the syllable. For this reason a space or newline
+must appear before the terminating @code{@}} to prevent it being
+included as part of the final syllable. Similarly,
+spaces must be inserted before and after the
+period or dot, @q{.}, separating the context name from the
+object name, as otherwise the two names are run together and
+the interpreter cannot recognise them. So the command should be:
+
+@example
+ \override Lyrics . LyricText #'font-shape = #'italic
+@end example
-@c Old stuff follows -td
+@warning{In lyrics always leave whitespace between the final
+syllable and the terminating brace.}
+
+@warning{In overrides in lyrics always place spaces around
+the dot between the context name and the object name.}
+
+@node Types of properties
+@subsection Types of properties
+
+@cindex Property types
+
+So far we have seen two types of property: @code{number} and
+@code{symbol}. To be valid, the value given to a property
+must be of the correct type and obey the rules for that type.
+The type of property is always shown in brackets after the
+property name in the IR. Here is a list of the types you may
+need, together with the rules for that type, and some examples.
+You must always add a hash symbol, @code{#}, of course,
+to the front of these values when they are entered in the
+@code{\override} command.
+
+@multitable @columnfractions .2 .45 .35
+@headitem Property type
+ @tab Rules
+ @tab Examples
+@item Boolean
+ @tab Either True or False, represented by #t or #f
+ @tab @code{#t}, @code{#f}
+@item Dimension (in staff space)
+ @tab A positive decimal number (in units of staff space)
+ @tab @code{2.5}, @code{0.34}
+@item Direction
+ @tab A valid direction constant or its numerical equivalent
+ @tab @code{#LEFT}, @code{#CENTER}, @code{#UP},
+ @code{1}, @code{-1}
+@item Integer
+ @tab A positive whole number
+ @tab @code{3}, @code{1}
+@item List
+ @tab A bracketed set of items separated by spaces,
+preceded by an apostrophe
+ @tab @code{'(left-edge staff-bar)}, @code{'(1)},
+ @code{'(1.0 0.25 0.5)}
+@item Markup
+ @tab Any valid markup
+ @tab @code{\markup @{ \italic "cresc." @}}
+@item Moment
+ @tab A fraction of a whole note constructed with the
+make-moment function
+ @tab @code{(ly:make-moment 1 4)},
+ @code{(ly:make-moment 3 8)}
+@item Number
+ @tab Any positive or negative decimal value
+ @tab @code{3.5}, @code{-2.45}
+@item Pair (of numbers)
+ @tab Two numbers separated by a @q{space . space} and enclosed
+in brackets preceded by an apostrophe
+ @tab @code{'(2 . 3.5)}, @code{'(0.1 . -3.2)}
+@item Symbol
+ @tab Any of the set of permitted symbols for that property,
+preceded by an apostrophe
+ @tab @code{'italic}, @code{'inside}
+@item Unknown
+ @tab A procedure or @code{#f} (to cause no action)
+ @tab @code{bend::print}, @code{ly:text-interface::print},
+ @code{#f}
+@item Vector
+ @tab A list of three items enclosed in brackets and preceded
+by a hash sign, @code{#}.
+ @tab @code{#(#t #t #f)}
+@end multitable
-@node Common tweaks
-@section Common tweaks
+@node Appearance of objects
+@section Appearance of objects
-blah blah
+Let us now put what we have learnt into practice with a few
+examples which show how tweaks may be used to change the
+appearance of the printed music.
@menu
-* Moving objects::
-* Fixing overlapping notation::
-* Other common tweaks::
-* Fitting music onto fewer pages::
+* Visibility and color of objects::
+* Size of objects::
+* Length and thickness of objects::
@end menu
-@node Moving objects
-@subsection Moving objects
+@node Visibility and color of objects
+@subsection Visibility and color of objects
+
+In the educational use of music we might wish to print a score
+with certain elements omitted as an exercise for the student,
+who is required to supply them. As a simple example,
+let us suppose the exercise is to supply the missing bar lines
+in a piece of music. But the bar lines are normally inserted
+automatically. How do we prevent them printing?
+
+Before we tackle this, let us remember that object properties
+are grouped in what are called @emph{interfaces} -- see
+@ref{Properties found in interfaces}. This is simply to
+group together those properties that are commonly required
+together -- if one of them is required for an object, so are
+the others. Some objects then need the properties in some
+interfaces, others need them from other interfaces. The
+interfaces which contain the properties required by a
+particular grob are listed in the IR at the bottom of the
+page describing that grob, and those properties may be
+viewed by looking at those interfaces.
+
+We explained how to find information about grobs in
+@ref{Properties of layout objects}. Using the same approach,
+we go to the IR to find the layout object which prints
+bar lines. Going via @emph{Backend} and @emph{All layout objects}
+we find there
+is a layout object called @code{BarLine}. Its properties include
+two that control its visibility: @code{break-visibility} and
+@code{stencil}. Barline also supports a number of interfaces,
+including the @code{grob-interface}, where we find the
+@code{transparent} and the @code{color} properties. All
+of these can affect the visibility of bar lines (and, of course,
+by extension, many other layout objects too.) Let's consider
+each of these in turn.
+
+@subheading stencil
+@cindex stencil property
+
+This property controls the appearance of the bar lines by specifying
+the symbol (glyph) which should be printed. In common
+with many other properties, it can be set to print nothing by
+setting its value to @code{#f}. Let's try it, as before, omitting
+the implied Context, @code{Voice}:
-This may come as a surprise, but LilyPond is not perfect. Some notation
-elements can overlap. This is unfortunate, but (in most cases) is easily
-solved.
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+{
+ \time 12/16
+ \override BarLine #'stencil = ##f
+ c4 b8 c d16 c d8 |
+ g, a16 b8 c d4 e16 |
+ e8
+}
+@end lilypond
-TODO: with the new spacing features in 2.12, these specific examples are no
-longer relevant. However, they still demonstrate powerful features
-of lilypond, so they remain until somebody creates some better examples.
+The bar lines are still printed. What is wrong? Go back to the
+IR and look again at the page giving the properties of BarLine.
+At the top of the page it says @qq{Barline objects are created
+by: Bar_engraver}. Go to the @code{Bar_engraver} page.
+At the bottom
+it gives a list of Contexts in which the bar engraver operates.
+All of them are of the type @code{Staff}, so the reason the
+@code{\override} command failed to work as expected is because
+@code{Barline} is not in the default @code{Voice} context.
+If the context
+is specified wrongly, the command simply does not work. No
+error message is produced, and nothing is logged in the log
+file. Let's try correcting it by adding the correct context:
@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
- % temporary code to break this example:
- \override TextScript #'outside-staff-priority = ##f
-e4^\markup{ \italic ritenuto } g b e
+{
+ \time 12/16
+ \override Staff.BarLine #'stencil = ##f
+ c4 b8 c d16 c d8 |
+ g, a16 b8 c d4 e16 |
+ e8
+}
@end lilypond
-@cindex padding
+Now the bar lines have vanished.
+
+@subheading break-visibility
-The easiest solution is to increase the distance between the object
-(in this case text, but it could easily be fingerings or dynamics
-instead) and the note. In LilyPond, this is called the
-@code{padding} property; it is measured in staff spaces. For most
-objects, this value is around 1.0 or less (it varies with each
-object). We want to increase it, so let's try 1.5
+@cindex break-visibility property
+
+We see from the @code{BarLine} properties in the IR that the
+@code{break-visibility} property requires a vector of three
+booleans.
+These control respectively whether bar lines are printed at
+the end of a line, in the middle of lines, and at the beginning
+of lines. For our example we want all bar lines to be suppressed,
+so the value we need is @code{#(#f #f #f)}.
+Let's try that, remembering
+to include the @code{Staff} context. Note also that in writing
+this value we have two hash signs before the opening bracket.
+One is required as part of the value to introduce a vector,
+and one is required, as always, to precede the value itself in
+the @code{\override} command.
@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
- % temporary code to break this example:
- \override TextScript #'outside-staff-priority = ##f
-\once \override TextScript #'padding = #1.5
-e4^\markup{ \italic ritenuto } g b e
+{
+ \time 12/16
+ \override Staff.BarLine #'break-visibility = ##(#f #f #f)
+ c4 b8 c d16 c d8 |
+ g, a16 b8 c d4 e16 |
+ e8
+}
@end lilypond
-That looks better, but it isn't quite big enough. After experimenting
-with a few values, we think 2.3 is the best number in this case. However,
-this number is merely the result of experimentation and my personal
-taste in notation. Try the above example with 2.3... but also try higher
-(and lower) numbers. Which do you think looks the best?
-
-The @code{staff-padding} property is closely related. @code{padding}
-controls the minimum amount of space between an object and the nearest
-other object (generally the note or the staff lines);
-@code{staff-padding} controls the minimum amount of space between an
-object and the staff. This is a subtle difference, but you can see
-the behavior here.
+And we see this too removes all the bar lines.
+
+@subheading transparent
+@cindex transparent property
+
+We see from the properties specified in the @code{grob-interface}
+page in the IR that the @code{transparent} property is a boolean.
+This
+should be set to @code{#t} to make the grob transparent.
+In this next example let us make the time signature invisible
+rather than the bar lines.
+To do this we need to find the grob name for the time signature.
+Back to
+the @q{All layout objects} page in the IR to find the properties
+of the @code{TimeSignature} layout object. This is produced by
+the @code{Time_signature_engraver} which you can check also lives
+in the @code{Staff} context and also supports the
+@code{grob-interface}. So the command to make the time signature
+transparent is:
@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
- % temporary code to break this example:
- \override TextScript #'outside-staff-priority = ##f
-c4^"piu mosso" b a b
-\once \override TextScript #'padding = #4.6
-c4^"piu mosso" d e f
-\once \override TextScript #'staff-padding = #4.6
-c4^"piu mosso" fis a g
-\break
-c'4^"piu mosso" b a b
-\once \override TextScript #'padding = #4.6
-c4^"piu mosso" d e f
-\once \override TextScript #'staff-padding = #4.6
-c4^"piu mosso" fis a g
+{
+ \time 12/16
+ \override Staff.TimeSignature #'transparent = ##t
+ c4 b8 c d16 c d8 |
+ g, a16 b8 c d4 e16 |
+ e8
+}
@end lilypond
-@cindex extra-offset
-
-Another solution gives us complete control over placing the object -- we
-can move it horizontally or vertically. This is done with the
-@code{extra-offset} property. It is slightly more complicated and can
-cause other problems. When we move objects with @code{extra-offset},
-the movement is done after LilyPond has placed all other objects. This
-means
-that the result can overlap with other objects.
+@noindent
+The time signature is gone, but this command leaves a gap where
+the time signature should be. Maybe this is what is wanted for
+an exercise for the student to fill it in, but in other
+circumstances a gap might be undesirable. To remove it, the
+stencil for the time signature should be set to @code{#f}
+instead:
@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
- % temporary code to break this example:
- \override TextScript #'outside-staff-priority = ##f
-\once \override TextScript #'extra-offset = #'( 1.0 . -1.0 )
-e4^\markup{ \italic ritenuto } g b e
+{
+ \time 12/16
+ \override Staff.TimeSignature #'stencil = ##f
+ c4 b8 c d16 c d8 |
+ g, a16 b8 c d4 e16 |
+ e8
+}
@end lilypond
-With @code{extra-offset}, the first number controls the horizontal
-movement (left is negative); the second number controls the vertical
-movement (up is positive). After a bit of experimenting, we decided
-that these values look good
+@noindent
+and the difference is obvious: setting the stencil to @code{#f}
+removes the object entirely; making the object @code{transparent}
+leaves it where it is, but makes it invisible.
+
+@subheading color
+@cindex color property
+
+Finally we could make the bar lines invisible by coloring
+them white. The @code{grob-interface} specifies that the
+color property value is a list, but there is no
+explanation of what that list should be. The list it
+requires is actually a list of values in internal units,
+but, to avoid having to know what these are, several ways
+are provided to specify colors. The first way is to use one
+of the @q{normal} colours listed in the first table in
+@ruser{List of colors}. To set the bar lines to white
+we write:
@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
- % temporary code to break this example:
- \override TextScript #'outside-staff-priority = ##f
-\once \override TextScript #'extra-offset = #'( -1.6 . 1.0 )
-e4^\markup{ \italic ritenuto } g b e
+{
+ \time 12/16
+ \override Staff.BarLine #'color = #white
+ c4 b8 c d16 c d8 |
+ g, a16 b8 c d4 e16 |
+ e8
+}
@end lilypond
@noindent
-Again, these numbers are simply the result of a few experiments and
-looking at the output. You might prefer the text to be slightly higher,
-or to the left, or whatever. Try it and look at the result!
+and again, we see the bar lines are not visible. Note that
+@emph{white} is not preceded by an apostrophe -- it is not
+a symbol, but a @emph{function}. When called, it provides
+the list of internal values required to set the color to
+white. The other colors in the normal list are functions
+too. To convince yourself this is working you might like
+to change the color to one of the other functions in the
+list.
+
+@cindex color, X11
+@cindex X11 colors
+
+The second way of changing the color is to use the list of
+X11 color names in the second list in @ruser{List of colors}.
+However, these must be preceded by another function, which
+converts X11 color names into the list of internal values,
+@code{x11-color}, like this:
-One final warning: in this section, we used
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+{
+ \time 12/16
+ \override Staff.BarLine #'color = #(x11-color 'white)
+ c4 b8 c d16 c d8 |
+ g, a16 b8 c d4 e16 |
+ e8
+}
+@end lilypond
-@example
-\once \override TextScript @dots{}
-@end example
+@noindent
+Note that in this case the function @code{x11-color} takes
+a symbol as an argument, so the symbol must be preceded by
+an apostrophe and the two enclosed in brackets.
-This tweaks the display of text for the next note. If the note has
-no text, this tweak does nothing (and does @strong{not} wait until
-the next bit of text). To change the behavior of everything after
-the command, omit the @code{\once}. To stop this tweak, use a
-@code{\revert}. This is explained in depth in
-@ruser{The \override command}.
+@cindex rgb colors
+@cindex color, rgb
-@lilypond[quote,fragment,ragged-right,verbatim,relative=3]
- % temporary code to break this example:
- \override TextScript #'outside-staff-priority = ##f
-c4^"piu mosso" b
-\once \override TextScript #'padding = #4.6
- a4 b
-c4^"piu mosso" d e f
-\once \override TextScript #'padding = #4.6
-c4^"piu mosso" d e f
-c4^"piu mosso" d e f
-\break
-\override TextScript #'padding = #4.6
-c4^"piu mosso" d e f
-c4^"piu mosso" d e f
-\revert TextScript #'padding
-c4^"piu mosso" d e f
+There is yet a third function, one which converts RGB values into
+internal colors -- the @code{rgb-color} function. This takes
+three arguments giving the intensities of the red, green and
+blue colors. These take values in the range 0 to 1. So to
+set the color to red the value should be @code{(rgb-color 1 0 0)}
+and to white it should be @code{(rgb-color 1 1 1)}:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+{
+ \time 12/16
+ \override Staff.BarLine #'color = #(rgb-color 1 1 1)
+ c4 b8 c d16 c d8 |
+ g, a16 b8 c d4 e16 |
+ e8
+}
@end lilypond
-@seealso
+Finally, there is also a grey scale available as part of the
+X11 set of colors. These range from black, @code{'grey0'},
+to white, @code{'grey100}, in steps of 1. Let's illustrate
+this by setting all the layout objects in our example to
+various shades of grey:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+{
+ \time 12/16
+ \override Staff.StaffSymbol #'color = #(x11-color 'grey30)
+ \override Staff.TimeSignature #'color = #(x11-color 'grey60)
+ \override Staff.Clef #'color = #(x11-color 'grey60)
+ \override Voice.NoteHead #'color = #(x11-color 'grey85)
+ \override Voice.Stem #'color = #(x11-color 'grey85)
+ \override Staff.BarLine #'color = #(x11-color 'grey10)
+ c4 b8 c d16 c d8 |
+ g, a16 b8 c d4 e16 |
+ e8
+}
+@end lilypond
-This manual: @ruser{The \override command}, @ref{Common tweaks}.
+@noindent
+Note the contexts associated with each of the layout objects.
+It is important to get these right, or the commands will not
+work! Remember, the context is the one in which the appropriate
+engraver is placed. The default context for engravers can be
+found by starting from the layout object, going from there to
+the engraver which produces it, and on the engraver page in the
+IR it tells you in which context the engraver will normally be
+found.
-@node Fixing overlapping notation
-@subsection Fixing overlapping notation
+@node Size of objects
+@subsection Size of objects
-In @ref{Moving objects}, we saw how to move a @code{TextScript}
-object. The same mechanism can be used to move other types of
-objects; simply replace @code{TextScript} with the name of
-another object.
+Let us begin by looking again at the earlier example
+see @ref{Nesting music expressions}) which showed
+how to introduce a new temporary staff, as in an @rglos{ossia}.
-To find the object name, look at the @q{@strong{see also}} at
-bottom of the relevant documentation page. For example, at
-the bottom of @ruser{Dynamics}, we see
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+\new Staff ="main" {
+ \relative g' {
+ r4 g8 g c4 c8 d |
+ e4 r8
+ <<
+ { f c c }
+ \new Staff \with {
+ alignAboveContext = "main" }
+ { f8 f c }
+ >>
+ r4 |
+ }
+ }
+@end lilypond
-@quotation
-@seealso
+Ossia are normally written without clef and time signature, and
+are usually printed slightly smaller than the main staff. We
+already know now how to remove the clef and time signature --
+we simply set the stencil of each to @code{#f}, as follows:
-Internals Reference: @internalsref{DynamicText}, @internalsref{Hairpin}.
-Vertical positioning of these symbols is handled by
-@internalsref{DynamicLineSpanner}.
-@end quotation
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+\new Staff ="main" {
+ \relative g' {
+ r4 g8 g c4 c8 d |
+ e4 r8
+ <<
+ { f c c }
+ \new Staff \with {
+ alignAboveContext = "main"
+ }
+ {
+ \override Staff.Clef #'stencil = ##f
+ \override Staff.TimeSignature #'stencil = ##f
+ { f8 f c }
+ }
+ >>
+ r4 |
+ }
+}
+@end lilypond
@noindent
-So to move dynamics around vertically, we use
+where the extra pair of braces after the @code{\with} clause are
+required to ensure the enclosed overrrides and music are applied
+to the ossia staff.
+
+But what is the difference between modifying the staff context by
+using @code{\with} and modifying the stencils of the clef and the
+time signature with \override? The main difference is that
+changes made in a @code{\with} clause are made at the time the
+context is created, and remain in force as the @strong{default}
+values for the duration of that context, whereas
+@code{\set} or @code{\override} commands embedded in the
+music are dynamic -- they make changes synchronised with
+a particular point in the music. If changes are unset or
+reverted using @code{\unset} or @code{\revert} they return to
+their default values, which will be the ones set in the
+@code{\with} clause, or if none have been set there, the normal
+default values.
+
+Some context properties
+can be modified only in @code{\with} clauses. These are those
+properties which cannot sensibly be changed after the context
+has been created. @code{alignAboveContext} and its partner,
+@code{alignBelowContext}, are two such properties -- once the
+staff has been created its alignment is decided and it would
+make no sense to try to change it later.
+
+The default values of layout object properties can also be set
+in @code{\with} clauses. Simply use the normal @code{\override}
+command leaving out the context name, since this is unambiguously
+defined as the context which the @code{\with} clause is modifying.
+If fact, an error will be generated if a context is specified
+in this location.
+
+So we could replace the example above with
-@example
-\override DynamicLineSpanner #'padding = #2.0
-@end example
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+\new Staff ="main" {
+ \relative g' {
+ r4 g8 g c4 c8 d |
+ e4 r8
+ <<
+ { f c c }
+ \new Staff \with {
+ alignAboveContext = "main"
+ % Don't print clefs in this staff
+ \override Clef #'stencil = ##f
+ % Don't print time signatures in this staff
+ \override TimeSignature #'stencil = ##f
+ }
+ { f8 f c }
+ >>
+ r4 |
+ }
+}
+@end lilypond
-We cannot list every object, but here is a list of the most
-common objects.
+Finally we come to changing the size of layout objects.
+
+Some layout objects are created as glyphs selected from
+a typeface font. These include note heads, accidentals, markup,
+clefs, time signatures, dynamics and lyrics.
+Their size is changed by modifying the
+@code{font-size} property, as we shall shortly see. Other
+layout objects such as slurs and ties -- in general, spanner
+objects -- are drawn individually, so there is no
+@code{font-size}
+associated with them. These objects generally derive their
+size from the objects to which they are attached, so usually
+there is no need to change their size manually. Still other
+properties such as the length of stems and bar lines, thickness
+of beams and other lines, and the separation of staff lines all
+need to be modified in special ways.
+
+Returning to the ossia example, let us first change the font-size.
+We can do this in two ways. We can either change the size of the
+fonts of each object type, like @code{NoteHead}s with commands
+like
-@multitable @columnfractions .33 .66
-@headitem Object type @tab Object name
-@item Dynamics (vertically) @tab @code{DynamicLineSpanner}
-@item Dynamics (horizontally) @tab @code{DynamicText}
-@item Ties @tab @code{Tie}
-@item Slurs @tab @code{Slur}
-@item Articulations @tab @code{Script}
-@item Fingerings @tab @code{Fingering}
-@item Text e.g. @code{^"text"} @tab @code{TextScript}
-@item Rehearsal / Text marks @tab @code{RehearsalMark}
-@end multitable
+@example
+\override NoteHead #'font-size = #-2
+@end example
+or we can change the size of all fonts by setting a special
+property, @code{fontSize}, using @code{\set}, or by including
+it in a @code{\with} clause (but without the @code{\set}).
-@node Other common tweaks
-@subsection Other common tweaks
+@example
+\set fontSize = #-2
+@end example
-Some overrides are so common that predefined commands are provided as
-short-cuts, such as @code{\slurUp} and @code{\stemDown}. These
-commands are described in the Notation Reference under the appropriate
-sections.
+Both of these statements would cause the font size to be reduced
+by 2 steps from its previous value, where each
+step reduces or increases the size by approximately 12%.
-The complete list of modifications available for each type of
-object (like slurs or beams) are documented in the Program
-Reference. However, many layout objects share properties which can be
-used to apply generic tweaks.
+Let's try it in our ossia example:
-@itemize
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+\new Staff ="main" {
+ \relative g' {
+ r4 g8 g c4 c8 d |
+ e4 r8
+ <<
+ { f c c }
+ \new Staff \with {
+ alignAboveContext = "main"
+ \override Clef #'stencil = ##f
+ \override TimeSignature #'stencil = ##f
+ % Reduce all font sizes by ~24%
+ fontSize = #-2
+ }
+ { f8 f c }
+ >>
+ r4 |
+ }
+}
+@end lilypond
-@cindex padding
+This is still not quite right. The note heads and flags are
+smaller, but the stems are too long in proportion and the
+staff lines are spaced too widely apart. These need to be
+scaled down in proportion to the font reduction. The next
+sub-section discusses how this is done.
-@item
-The @code{padding} property can be set to increase
-(or decrease) the distance between symbols that are printed
-above or below notes. This applies to all objects with
-@code{side-position-interface}.
+@node Length and thickness of objects
+@subsection Length and thickness of objects
-@lilypond[quote,fragment,relative=1,verbatim]
-c2\fermata
-\override Script #'padding = #3
-b2\fermata
-@end lilypond
+@cindex Distances
+@cindex Thickness
+@cindex Length
+@cindex magstep
+@cindex size, changing
+@cindex stem length, changing
+@cindex staff line spacing, changing
+
+Distances and lengths in LilyPond are generally measured in
+staff-spaces, the distance between adjacent lines in the staff,
+(or occasionally half staff spaces) while most @code{thickness}
+properties are measured in units of an internal property called
+@code{line-thickness.} For example, by default, the lines of
+hairpins are given a thickness of 1 unit of @code{line-thickness},
+while the @code{thickness} of a note stem is 1.3. Note, though,
+that some thickness properties are different; for example, the
+thickness of beams is measured in staff-spaces.
+
+So how are lengths to be scaled in proportion to the font size?
+This can be done with the help of a special function called
+@code{magstep} provided for exactly this purpose. It takes
+one argument, the change in font size (#-2 in the example above)
+and returns a scaling factor suitable for reducing other
+objects in proportion. It is used like this:
-@lilypond[quote,fragment,relative=1,verbatim]
-% This will not work, see below:
-\override MetronomeMark #'padding = #3
-\tempo 4=120
-c1
-% This works:
-\override Score.MetronomeMark #'padding = #3
-\tempo 4=80
-d1
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+\new Staff ="main" {
+ \relative g' {
+ r4 g8 g c4 c8 d |
+ e4 r8
+ <<
+ { f c c }
+ \new Staff \with {
+ alignAboveContext = "main"
+ \override Clef #'stencil = ##f
+ \override TimeSignature #'stencil = ##f
+ fontSize = #-2
+ % Reduce stem length and line spacing to match
+ \override StaffSymbol #'staff-space = #(magstep -2)
+ }
+ { f8 f c }
+ >>
+ r4 |
+ }
+}
@end lilypond
-Note in the second example how important it is to figure out what
-context handles a certain object. Since the @code{MetronomeMark} object
-is handled in the @code{Score} context, property changes in the
-@code{Voice} context will not be noticed. For more details, see
-@ruser{Constructing a tweak}.
+@noindent
+Since the length of stems and many other length-related properties
+are always calculated relative to the
+value of the @code{staff-space} property these are automatically
+scaled down in length too. Note that this affects only the
+vertical scale of the ossia -- the horizontal scale is determined
+by the layout of the main music in order to remain synchronised
+with it, so it is not affected by any of these changes in size.
+Of course, if the scale of all the main music were changed in this
+way then the horizontal spacing would be affected. This is
+discussed later in the layout section.
+
+This, then, completes the creation of an ossia. The sizes and
+lengths of all other objects may be modified in analogous ways.
+
+For small changes in scale, as in the example above, the
+thickness of the various drawn lines such as bar lines,
+beams, hairpins, slurs, etc does not usually require global
+adjustment. If the thickness of any particular layout object
+needs to be adjusted this can be best achieved by overriding its
+@code{thickness} property. An example of changing the thickness
+of slurs was shown above in @ref{Properties of layout objects}.
+The thickness of all drawn objects (i.e., those not produced
+from a font) may be changed in the same way.
+
+
+@node Placement of objects
+@section Placement of objects
-@cindex extra-offset
+@menu
+* Automatic behaviour::
+* Within-staff objects::
+* Outside staff objects::
+@end menu
-@item
-The @code{extra-offset} property moves objects around
-in the output; it requires a pair of numbers. The first number
-controls horizontal movement; a positive number will
-move the object to the right. The second number controls vertical
-movement; a positive number will move it higher. The
-@code{extra-offset} property is a low-level feature: the
-formatting engine is completely oblivious to these offsets.
-In the following example, the second fingering is moved a little to
-the left, and 1.8 staff space downwards:
+@node Automatic behaviour
+@subsection Automatic behaviour
+
+There are some objects in musical notation that belong to
+the staff and there are other objects that should be
+placed outside the staff. These are called within-staff
+objects and outside-staff objects respectively.
+
+Within-staff objects are those that are located on the staff
+-- note heads, stems, accidentals, etc. The positions of
+these are usually fixed by the music itself -- they are
+vertically positioned on specific lines of the staff or are
+tied to other objects that are so positioned. Collisions of
+note heads, stems and accidentals in closely set chords are
+normally avoided automatically. There are commands and
+overrides which can modify this automatic behaviour, as we
+shall shortly see.
+
+Objects belonging outside the staff include things such as
+rehearsal marks, text and dynamic markings. LilyPond's rule for
+the vertical placement of outside-staff objects is to place them
+as close to the staff as possible but not so close that they
+collide with any other object. LilyPond uses the
+@code{outside-staff-priority} property to determine the order in
+which the objects should be placed, as follows.
+
+First, LilyPond places all the within-staff objects.
+Then it sorts the outside-staff objects according to their
+@code{outside-staff-priority}. The outside-staff objects are
+taken one by one, beginning with the object with the lowest
+@code{outside-staff-priority}, and placed so that they do not
+collide with any objects that have already been placed. That is,
+if two outside-staff grobs are competing for the same space, the
+one with the lower @code{outside-staff-priority} will be placed
+closer to the staff. If two objects have the same
+@code{outside-staff-priority} the one encountered first will be
+placed closer to the staff.
+
+In the following example all the markup texts have the same
+priority (since it is not explicity set). Note that @q{Text3}
+is automatically positioned close to the staff again, nestling
+under @q{Text2}.
-@lilypond[quote,fragment,relative=1,verbatim]
-\stemUp
-f-5
-\once \override Fingering
- #'extra-offset = #'(-0.3 . -1.8)
-f-5
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+c2^"Text1"
+c^"Text2"
+c^"Text3"
+c^"Text4"
@end lilypond
-@item
-Setting the @code{transparent} property will cause an object to be printed
-in @q{invisible ink}: the object is not printed, but all its other
-behavior is retained. The object still takes up space, it takes part in
-collisions, and slurs, ties, and beams can be attached to it.
+Staves are also positioned, by default, as closely together as
+possible (subject to a minimum separation). If notes project
+a long way towards an adjacent staff they will force the
+staves further apart only if an overlap of the notation
+would otherwise occur. The following example demonstrates
+this @q{nestling} of the notes on adjacent staves:
+
+@lilypond[quote,ragged-right,verbatim]
+<<
+ \new Staff {
+ \relative c' { c a, }
+ }
+ \new Staff {
+ \relative c'''' { c a, }
+ }
+>>
+@end lilypond
-@cindex transparent objects
-@cindex removing objects
-@cindex hiding objects
-@cindex invisible objects
-The following example demonstrates how to connect different voices
-using ties. Normally, ties only connect two notes in the same
-voice. By introducing a tie in a different voice,
-@lilypond[quote,fragment,relative=2]
-<< {
- b8~ b8\noBeam
-} \\ {
- b[ g8]
-} >>
+@node Within-staff objects
+@subsection Within-staff objects
+
+We have already seen how the commands @code{\voiceXXX} affect
+the direction of slurs, ties, fingering and
+everything else which depends on the direction of the stems.
+These commands are essential when writing polyphonic music to
+permit interweaving melodic lines to be distinguished.
+But occasionally it may be necessary to override this automatic
+behaviour. This can be done for whole sections of music or even
+for an individual note. The property which controls this
+behaviour is the @code{direction} property of each layout object.
+We first explain what this does, and then introduce a number of
+ready-made commands which avoid your having to code explicit
+overrides for the more common modifications.
+
+Some layout objects like slurs and ties curve, bend or point
+either up or down; others like stems and flags also move to
+right or left when they point up or down. This is controlled
+automatically when @code{direction} is set.
+
+The following example shows in bar 1 the default behaviour of
+stems,
+with those on high notes pointing down and those on low notes
+pointing up, followed by four notes with all stems forced down,
+four notes with all stems forced up, and finally four notes
+reverted back to the default behaviour.
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+a4 g c a
+\override Stem #'direction = #DOWN
+a g c a
+\override Stem #'direction = #UP
+a g c a
+\revert Stem #'direction
+a g c a
@end lilypond
-@noindent
-and blanking the first up-stem in that voice, the tie appears to cross
-voices:
+Here we use the constants @code{DOWN} and @code{UP}.
+These have the values @code{-1} and @code{+1} respectively, and
+these numerical values may be used instead. The value @code{0}
+may also be used in some cases. It is simply treated as meaning
+@code{UP} for stems, but for some objects it means @q{center}.
+There is a constant, @code{CENTER} which has the value @code{0}.
+
+However, these explicit overrides are not usually used, as there
+are simpler equivalent predefined commands available.
+Here is a table of the commonest. The meaning of each is stated
+where it is not obvious.
+
+@multitable @columnfractions .2 .2 .2 .4
+@headitem Down/Left
+ @tab Up/Right
+ @tab Revert
+ @tab Effect
+@item @code{\arpeggioDown}
+ @tab @code{\arpeggioUp}
+ @tab @code{\arpeggioNeutral}
+ @tab Arrow is at bottom, at top, or no arrow
+@item @code{\dotsDown}
+ @tab @code{\dotsUp}
+ @tab @code{\dotsNeutral}
+ @tab Direction of movement to avoid staff lines
+@item @code{\dynamicDown}
+ @tab @code{\dynamicUp}
+ @tab @code{\dynamicNeutral}
+ @tab
+@item @code{\phrasingSlurDown}
+ @tab @code{\phrasingSlurUp}
+ @tab @code{\phrasingSlurNeutral}
+ @tab Note: distinct from slur commands
+@item @code{\slurDown}
+ @tab @code{\slurUp}
+ @tab @code{\slurNeutral}
+ @tab
+@item @code{\stemDown}
+ @tab @code{\stemUp}
+ @tab @code{\stemNeutral}
+ @tab
+@item @code{\textSpannerDown}
+ @tab @code{\textSpannerUp}
+ @tab @code{\textSpannerNeutral}
+ @tab Text entered as spanner is below/above staff
+@item @code{\tieDown}
+ @tab @code{\tieUp}
+ @tab @code{\tieNeutral}
+ @tab
+@item @code{\tupletDown}
+ @tab @code{\tupletUp}
+ @tab @code{\tupletNeutral}
+ @tab Tuplets are below/above notes
+@end multitable
+Note that these predefined commands may @strong{not} be
+preceded by @code{\once}. If you wish to limit the
+effect to a single note you must either use the equivalent
+@code{\once \override} command or use the predefined command
+followed after the affected note by the corresponding
+@code{\xxxNeutral} command.
-@lilypond[quote,fragment,relative=2,verbatim]
-<< {
- \once \override Stem #'transparent = ##t
- b8~ b8\noBeam
-} \\ {
- b[ g8]
-} >>
+@subheading Fingering
+@cindex fingering, placement
+
+The placement of fingering is also affected by the value
+of its @code{direction} property, but there are special
+commands which allow the fingering of individual notes
+of chords to be controlled, with the fingering being placed
+above, below, to the left or to the right of each note.
+
+First, here's the effect of @code{direction} on fingering,
+the first bar shows the default, then the effect of specifying
+@code{DOWN} and @code{UP}:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+c-5 a-3 f-1 c'-5
+\override Fingering #'direction = #DOWN
+c-5 a-3 f-1 c'-5
+\override Fingering #'direction = #UP
+c-5 a-3 f-1 c'-5
@end lilypond
-To make sure that the just-blanked stem doesn't squeeze the tie too much,
-we also lengthen the stem, by setting the @code{length} to
-@code{8},
+This is how to control fingering on single notes, but the
+@code{direction}
+property is ignored for chords. Instead, by default, the
+fingering is automatically placed both above and below the
+notes of a chord, as shown:
-@lilypond[quote,fragment,relative=2,verbatim]
-<< {
- \once \override Stem #'transparent = ##t
- \once \override Stem #'length = #8
- b8~ b8\noBeam
-} \\ {
- b[ g8]
-} >>
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+<c-5 g-3>
+<c-5 g-3 e-2>
+<c-5 g-3 e-2 c-1>
@end lilypond
-@end itemize
+Greater control over the placement of fingering of the
+individual notes in a chord is possible by using
+the @code{\set fingeringOrientations} command. The format of
+this command is
-@cindex Tweaks, distances
-@cindex Distances
+@example
+@code{\set fingeringOrientations = #'([up] [left/right] [down])}
+@end example
+
+@noindent
+@code{\set} is used because @code{fingeringOrientations} is a
+property of the @code{Voice} context, created and used by the
+@code{New_fingering_engraver}.
+
+The property may be set to a list of one to three values.
+It controls whether fingerings may be placed above (if
+@code{up} appears in the list), below (if @code{down} appears),
+to the left (if @code{left} appears, or to the right
+(if @code{right} appears). Conversely, if a location is not
+listed, no fingering is placed there. LilyPond takes these
+contraints and works out the best placement for the fingering
+of the notes of the following chords. Note that @code{left} and
+@code{right} are mutually exclusive -- fingering may be placed
+only on one side or the other, not both.
+
+To control the placement of the fingering of a single note
+using this command it is necessary to write it as a single
+note chord by placing angle brackets round it.
+
+Here are a few examples:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=1]
+\set fingeringOrientations = #'(left)
+<f-2>
+< c-1 e-2 g-3 b-5 > 4
+\set fingeringOrientations = #'(left)
+<f-2>
+< c-1 e-2 g-3 b-5 > 4
+\set fingeringOrientations = #'(up left down)
+<f-2>
+< c-1 e-2 g-3 b-5 > 4
+\set fingeringOrientations = #'(up left)
+<f-2>
+< c-1 e-2 g-3 b-5 > 4
+\set fingeringOrientations = #'(right)
+<f-2>
+< c-1 e-2 g-3 b-5 > 4
+@end lilypond
+
+@noindent
+If the fingering seems a little crowded the @code{font-size}
+could be reduced. The default value can be seen from the
+@code{Fingering} object in the IR to be @code{-5}, so let's
+try @code{-7}:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=1]
+\override Fingering #'font-size = #-7
+\set fingeringOrientations = #'(left)
+<f-2>
+< c-1 e-2 g-3 b-5 > 4
+\set fingeringOrientations = #'(left)
+<f-2>
+< c-1 e-2 g-3 b-5 > 4
+\set fingeringOrientations = #'(up left down)
+<f-2>
+< c-1 e-2 g-3 b-5 > 4
+\set fingeringOrientations = #'(up left)
+<f-2>
+< c-1 e-2 g-3 b-5 > 4
+\set fingeringOrientations = #'(right)
+<f-2>
+< c-1 e-2 g-3 b-5 > 4
+@end lilypond
+
+@node Outside staff objects
+@subsection Outside staff objects
+
+Outside-staff objects are automatically placed to avoid collisions.
+Objects with the lower value of the @code{outside-staff-priority}
+property are placed nearer to the staff, and other outside-staff
+objects are then raised as far as necessary to avoid collisions.
+The @code{outside-staff-priority} is defined in the
+@code{grob-interface} and so is a property of all layout objects.
+By default it is set to @code{#f} for all within-staff objects,
+and to a numerical value appropriate to each outside-staff object
+when the object is created. The following table shows
+the default numerical values for some of the commonest
+outside-staff objects which are, by default, placed in the
+@code{Staff} or @code{Voice} contexts.
+
+@multitable @columnfractions .3 .3 .3
+@headitem Layout Object
+ @tab Priority
+ @tab Controls position of:
+@item @code{MultiMeasureRestText}
+ @tab @code{450}
+ @tab Text over full-bar rests
+@item @code{TextScript}
+ @tab @code{450}
+ @tab Markup text
+@item @code{OttavaBracket}
+ @tab @code{400}
+ @tab Ottava brackets
+@item @code{TextSpanner}
+ @tab @code{350}
+ @tab Text spanners
+@item @code{DynamicLineSpanner}
+ @tab @code{250}
+ @tab All dynamic markings
+@item @code{VoltaBracketSpanner}
+ @tab @code{100}
+ @tab Volta brackets
+@item @code{TrillSpanner}
+ @tab @code{50}
+ @tab Spanning trills
+@end multitable
+
+Here is an example showing the default placement of some of
+these.
+
+@cindex text spanner
+@funindex \startTextSpan
+@funindex \stopTextSpan
+@cindex ottava bracket
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=1]
+% Set details for later Text Spanner
+\override TextSpanner #'bound-details #'left #'text
+ = \markup { \small \bold Slower }
+% Place dynamics above staff
+\dynamicUp
+% Start Ottava Bracket
+#(set-octavation 1)
+c' \startTextSpan
+% Add Dynamic Text
+c\pp
+% Add Dynamic Line Spanner
+c\<
+% Add Text Script
+c^Text
+c c
+% Add Dynamic Text
+c\ff c \stopTextSpan
+% Stop Ottava Bracket
+#(set-octavation 0)
+c, c c c
+@end lilypond
+
+This example also shows how to create Text Spanners --
+text with extender lines above a section of music. The
+spanner extends from the @code{\startTextSpan} command to
+the @code{\stopTextSpan} command, and the format of the
+text is defined by the @code{\override TextSpanner} command.
+For more details see @ruser{Text spanners}.
+
+It also shows how ottava brackets are created.
+
+Note that bar numbers, metronome marks and rehearsal marks
+are not shown. By default these are created in the
+@code{Score} context and their @code{outside-staff-priority}
+is ignored relative to the layout objects which are created
+in the @code{Staff} context.
+If you wish to place bar numbers, metronome marks or rehearsal
+marks in accordance with the value of their
+@code{outside-staff-priority} the @code{Bar_number_engraver},
+@code{Metronome_mark_engraver} or @code{Mark_engraver} respectively
+should be removed from the @code{Score} context and placed in the
+top @code{Staff} context. If this is done, these marks will be
+given the following default @code{outside-staff-priority} values:
+
+@multitable @columnfractions .3 .3
+@headitem Layout Object @tab Priority
+@item @code{RehearsalMark} @tab @code{1500}
+@item @code{MetronomeMark} @tab @code{1000}
+@item @code{BarNumber} @tab @code{ 100}
+@end multitable
+
+If the default values of @code{outside-staff-priority} does not
+give you the placing you want, the priority of any of the objects
+may be overridden. Suppose we would
+like the ottava bracket to be placed below the text spanner in the
+example above. All we need to do is to look up the priority of
+@code{OttavaBracket} in the IR or in the tables above, and reduce
+it to a value lower than that of a @code{TextSpanner}, remembering
+that @code{OttavaBracket} is created in the @code{Staff} context:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=1]
+% Set details for later Text Spanner
+\override TextSpanner #'bound-details #'left #'text
+ = \markup { \small \bold Slower }
+% Place dynamics above staff
+\dynamicUp
+%Place following Ottava Bracket below Text Spanners
+\once \override Staff.OttavaBracket #'outside-staff-priority = #340
+% Start Ottava Bracket
+#(set-octavation 1)
+c' \startTextSpan
+% Add Dynamic Text
+c\pp
+% Add Dynamic Line Spanner
+c\<
+% Add Text Script
+c^Text
+c c
+% Add Dynamic Text
+c\ff c \stopTextSpan
+% Stop Ottava Bracket
+#(set-octavation 0)
+c, c c c
+@end lilypond
+
+Changing the @code{outside-staff-priority} can also be used to
+control the vertical placement of individual objects, although
+the results may not always be desirable. Suppose we would
+like @qq{Text3} to be placed above @qq{Text4} in the example
+under Automatic behaviour, above (see @ref{Automatic behaviour}).
+All we need to do is to look up the priority of @code{TextScript}
+in the IR or in the tables above, and increase the priority of
+@qq{Text3} to a higher value:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+c2^"Text1"
+c^"Text2"
+\once \override TextScript #'outside-staff-priority = #500
+c^"Text3"
+c^"Text4"
+@end lilypond
+
+This certainly lifts @qq{Text3} above @qq{Text4} but it also
+lifts it above @qq{Text2}, and @qq{Text4} now drops down.
+Perhaps this is not so good. What we would really like to do
+is to position all the annotation at the same distance above
+the staff? To do this, we clearly
+will need to space the notes out horizontally to make more
+room for the text. This is done using the @code{textLengthOn}
+command.
-Distances in LilyPond are measured in staff-spaces, while most
-thickness properties are measured in line-thickness. Some
-properties are different; for example, the thickness of beams
-are measured in staff-spaces. For more information, see the
-relevant portion of the program reference.
+@subheading \textLengthOn
+@funindex \textLengthOn
+@cindex notes, spreading out with text
-@node Fitting music onto fewer pages
-@subsection Fitting music onto fewer pages
+By default, text produced by markup takes up no horizontal space
+as far as laying out the music is concerned. The @code{\textLengthOn}
+command reverses this behaviour, causing the notes to be spaced
+out as far as is necessary to accommodate the text:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+\textLengthOn % Cause notes to space out to accommodate text
+c2^"Text1"
+c^"Text2"
+c^"Text3"
+c^"Text4"
+@end lilypond
+
+The command to revert to the default behaviour is
+@code{\textLengthOff}. Remember @code{\once} only works with
+@code{\override}, @code{\set}, @code{\revert} or @code{unset},
+so cannot be used with @code{\textLengthOn}.
+
+Markup text will also avoid notes which project above the staff.
+If this is not desired, the automatic displacement upwards may
+be turned off by setting the priority to @code{#f}. Here's an
+example to show how markup text interacts with such notes.
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+% This markup is short enough to fit without collision
+c2^"Tex"
+c''2
+R1
+% This is too long to fit, so it is displaced upwards
+c,,2^"Text"
+c''2
+R1
+% Turn off collision avoidance
+\once \override TextScript #'outside-staff-priority = ##f
+c,,2^"Long Text "
+c''2
+R1
+% Turn off collision avoidance
+\once \override TextScript #'outside-staff-priority = ##f
+\textLengthOn % and turn on textLengthOn
+c,,2^"Long Text " % Spaces at end are honoured
+c''2
+@end lilypond
-Sometimes you can end up with one or two staves on a second
-(or third, or fourth...) page. This is annoying, especially
-if you look at previous pages and it looks like there is plenty
-of room left on those.
-When investigating layout issues, @code{annotate-spacing} is
-an invaluable tool. This command prints the values of various
-layout spacing commands; see @ruser{Displaying spacing}, for more
-details. From the output of @code{annotate-spacing}, we can
-see which margins we may wish to alter.
+@subheading Dynamics
-Other than margins, there are a few other options to save space:
+Dynamic markings will normally be positioned beneath the
+staff, but may be positioned above with the @code{dynamicUp}
+command. They will be positioned vertically relative to the
+note to which they are attached, and will float below (or above)
+all within-staff objects such as phrasing slurs and bar numbers.
+This can give quite acceptable results, as this example
+shows:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=1]
+\clef "bass"
+\key aes \major
+\time 9/8
+\dynamicUp
+bes4.~\f\< \( bes4 bes8 des4\ff\> c16 bes\! |
+ees,2.~\)\mf ees4 r8 |
+@end lilypond
+
+However, if the notes and attached dynamics are close
+together the automatic placement will avoid collisions
+by displacing later dynamic markings further away, but this may
+not be the optimum placement, as this rather artificial example
+shows:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+\dynamicUp
+a4\f b\mf c\mp b\p
+@end lilypond
+
+@noindent
+Should a similar situation arise in @q{real} music, it may
+be preferable to space out the notes
+a little further, so the dynamic markings can all fit at the
+same vertical distance from the staff. We were able to do this
+for markup text by using the @code{\textLengthOn} command, but there
+is no equivalent command for dynamic marks. So we shall have to
+work out how to do this using @code{\override} commands.
+
+@subheading Grob sizing
+
+@cindex grob sizing
+@cindex sizing grobs
+@cindex @code{X-offset}
+@cindex @code{Y-offset}
+@cindex @code{X-extent}
+@cindex @code{Y-extent}
+
+First we must learn how grobs are sized. All grobs have a
+reference point defined within them which is used to position
+them relative to their parent object. This point in the grob
+is then positioned at a horizontal distance, @code{X-offset},
+and at a vertical distance, @code{Y-offset}, from its parent.
+The horizontal extent of the object is given by a pair of
+numbers, @code{X-extent}, which say where the left and right
+edges are relative to the reference point. The vertical extent
+is similarly defined by a pair of numbers, @code{Y-extent}.
+These are properties of all grobs which support the
+@code{grob-interface}.
+
+@cindex @code{extra-spacing-width}
+
+By default, outside-staff objects are given a width of zero so
+that they may overlap in the horizontal direction. This is done
+by the trick of adding infinity to the leftmost extent and
+minus infinity to the rightmost extent by setting the
+@code{extra-spacing-width} to @code{'(+inf.0 . -inf.0)}. So
+to ensure they do not overlap in the horizontal direction we
+must override this value of @code{extra-spacing-width} to
+@code{'(0 . 0)} so the true width shines through. This is
+the command to do this for dynamic text:
+
+@example
+\override DynamicText #'extra-spacing-width = #'(0 . 0)
+@end example
+
+@noindent
+Let's see if this works in our previous example:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+\dynamicUp
+\override DynamicText #'extra-spacing-width = #'(0 . 0)
+a4\f b\mf c\mp b\p
+@end lilypond
+
+@noindent
+Well, it has certainly stopped the dynamic marks being
+displaced, but two problems remain. The marks should be
+spaced a little further apart and it would be better
+if they were all the same distance from the staff.
+We can solve the first problem easily. Instead of making
+the @code{extra-spacing-width} zero we could add a little
+more to it. The units are the space between two staff
+lines, so moving the left edge half a unit to the left and the
+right edge half a unit to the right should do it:
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+\dynamicUp
+% Extend width by 1 staff space
+\override DynamicText #'extra-spacing-width = #'(-0.5 . 0.5)
+a4\f b\mf c\mp b\p
+@end lilypond
+
+@noindent
+This looks better, but maybe we would prefer the dynamic marks
+to be aligned along the same baseline rather than going up and
+down with the notes. The property to do this is
+@code{staff-padding} which is covered in the following section.
+
+
+@node Collisions of objects
+@section Collisions of objects
+
+@menu
+* Moving objects::
+* Fixing overlapping notation::
+* Real music example::
+@end menu
+
+@node Moving objects
+@subsection Moving objects
+
+This may come as a surprise, but LilyPond is not perfect. Some
+notation elements can overlap. This is unfortunate, but in fact
+rather rare. Usually the need to move objects is for clarity or
+aesthetic reasons -- they would look better with a little more
+or a little less space around them.
+
+There are three main main approaches to resolving overlapping
+notation. They should be considered in the following order:
+
+@enumerate
+@item
+The @strong{direction} of one of the overlapping objects may
+be changed using the predefined commands listed above for
+within-staff objects (see @ref{Within-staff objects}).
+Stems, slurs, beams, ties, dynamics, text and tuplets may be
+repositioned easily in this way. The limitation is that you
+have a choice of only two positions, and neither may be
+suitable.
+
+@item
+The @strong{object properties}, which LilyPond uses
+when positioning layout objects, may be modified using
+@code{\override}. The advantages
+of making changes to this type of property are (a) that some
+other objects will be moved automatically if necessary to make
+room and (b) the single override can apply to all instances of
+the same type of object. Such properties include:
@itemize
+
+@item
+@code{direction}
+
+This has already been covered in some detail -- see
+@ref{Within-staff objects}.
+
@item
-You may tell LilyPond to place systems as close together as
-possible (to fit as many systems as possible onto a page), but
-then to space those systems out so that there is no blank
-space at the bottom of the page.
+@code{padding}, @code{left-padding},
+@code{right-padding}, @code{staff-padding}
+
+@cindex left-padding property
+@cindex padding property
+@cindex right-padding property
+@cindex staff-padding property
+As an object is being positioned the value of its @code{padding}
+property specifies the gap that must be left between itself and
+the nearest edge of the object against which it is being
+positioned. Note that it is the @code{padding} value of the object
+@strong{being placed} that is used;
+the @code{padding} value of the object which is already placed is
+ignored. Gaps specified by @code{padding} can be applied
+to all objects which support the @code{side-position-interface}.
+
+Instead of @code{padding}, the placement of groups of accidentals
+is controlled by @code{left-padding} and @code{right-padding}.
+These properties are to be found in the @code{AccidentalPlacement}
+object which, note, lives in the @strong{staff} context. Because
+accidentals are always positioned after and to the left of
+note heads only the @code{right-padding} property has any effect.
+
+The @code{staff-padding} property is closely related to the
+@code{padding} property: @code{padding}
+controls the minimum amount of space between any object which
+supports the @code{side-position-interface} and the nearest
+other object (generally the note or the staff lines);
+@code{staff-padding} applies only to those objects which are always
+set outside the staff -- it controls the minimum amount of space
+that should be inserted between that object and the staff. Note
+that @code{staff-padding} has no effect on objects which are
+positioned relative to the note rather than the staff, even though
+it may be overridden without error for such objects -- it is simply
+ignored.
+
+To discover which padding property is required for the object
+you wish to reposition, you
+need to return to the IR and look up the object's properties.
+Be aware that the padding properties might not be located in the
+obvious object, so look in objects that appear to be related.
+
+All padding values are measured in staff spaces. For most
+objects, this value is set by default to be around 1.0 or less
+(it varies with each object). It may be overridden if a larger
+(or smaller) gap is required.
+
+@item
+@code{self-alignment-X}
+
+@cindex self-alignment-X property
+This property can be used to align the object to the left, to
+the right, or to center it with respect to the parent object's
+reference point. It may be used with all objects which support
+the @code{self-alignment-interface}. In general these are objects
+that contain text. The values are @code{LEFT}, @code{RIGHT}
+or @code{CENTER}. Alternatively, a numerical value between
+@code{-1} and @code{+1} may be specified, where @code{-1} is
+left-aligned, @code{+1} is right-aligned, and numbers in between
+move the text progressively from left-aligned to right-aligned.
+Numerical values greater than @code{1} may be specified to move
+the text even further to the left, or less than @code{-1} to
+move the text even further to the right. A change of @code{1}
+in the value corresponds to a movement of half the text's length.
+
+@item
+@code{extra-spacing-width}
+
+@cindex extra-spacing-width property
+This property is available for all objects which support the
+@code{item-interface}. It takes two numbers, the first is added
+to the leftmost extent and the second is added to the rightmost
+extent. Negative numbers move the edge to the left, positive to
+the right, so to widen an object the first number must be negative,
+the second positive. Note that not all objects honour both
+numbers. For example, the @code{Accidental} object only takes
+notice of the first (left edge) number.
+
+@item
+@code{staff-position}
+
+@cindex staff-position property
+@code{staff-position} is a property of the
+@code{staff-symbol-referencer-interface}, which is supported by
+objects which are positioned relative to the staff. It specifies
+the vertical position of the object relative to the center line
+of the staff in half staff-spaces. It is useful in resolving
+collisions between layout objects like multi-measure rests, ties
+and notes in different voices.
+
+@item
+@code{force-hshift}
+
+@cindex force-hshift property
+
+Closely spaced notes in a chord, or notes occuring at the same
+time in different voices, are arranged in two, occasionally more,
+columns to prevent the note heads overlapping. These are called
+note columns, and an object called @code{NoteColumn} is created
+to lay out the notes in that column.
+
+The @code{force-hshift}
+property is a property of a @code{NoteColumn} (actually of the
+@code{note-column-interface}). Changing it permits a note column
+to be moved in units appropriate to a note column, viz. the note
+head width of the first voice note. It should be used in
+complex situations where the normal @code{\shiftOn} commands (see
+@ref{Explicitly instantiating voices}) do
+not resolve the note conflict. It is preferable to the
+@code{extra-offset} property for this purpose as there is no need
+to work out the distance in staff-spaces, and moving the notes
+into or out of a @code{NoteColumn} affects other actions such as
+merging note heads.
+
+@end itemize
+
+Objects do not all have all of these properties in general.
+It is necessary to go to the IR to look up which properties
+are available for the object in question.
+
+@item
+Finally, when all else fails, objects may be manually repositioned
+relative to the staff center line verically, or by
+displacing them by any distance to a new position. The
+disadvantages are that the correct values for the repositioning
+have to be worked out, often by trial and error, for every object
+individually, and, because the movement is done after LilyPond has
+placed all other objects, the user is responsible for avoiding any
+collisions that might ensue. But the main difficulty with this
+approach is that the repositioning values may need to be reworked
+if the music is later modified. The properties that can be used
+for this type of manual repositioning are:
+
+@table @code
+@item extra-offset
+@cindex extra-offset property
+This property applies to any layout object
+supporting the @code{grob-interface}. It takes a pair of
+numbers which specify the extra displacement in the horizontal and
+vertical directions. Negative numbers move the object to
+the left or down. The units are staff-spaces. The extra
+displacement is made after the typesetting of objects is
+finished, so an object may be repositioned anywhere without
+affecting anything else.
+
+@item positions
+@cindex positions property
+This is most useful for manually adjusting the slope and height
+of beams, slurs, and tuplets. It takes a pair of numbers
+giving the position of the left and right ends of the beam, slur,
+etc. relative to the center line of the staff. Units are
+staff-spaces. Note, though, that slurs and phrasing slurs cannot
+be repositioned by arbitrarily large amounts. LilyPond first
+generates a list of possible positions for the slur and by default
+finds the slur that @qq{looks best}. If the @code{positions}
+property has been overridden the slur that is closest to the
+requested positions is selected from the list.
+@end table
+
+Objects do not all have all of these properties in general.
+It is necessary to go to the IR to look up which properties
+are available for the object in question.
+
+@end enumerate
+
+Here is a list of the objects which are most likely to be
+involved in collisions, together with the name of the object which
+should be looked up in the IR in order to discover which properties
+should be used to move them.
+
+@multitable @columnfractions .5 .5
+@headitem Object type @tab Object name
+@item Articulations @tab @code{Script}
+@item Beams @tab @code{Beam}
+@item Dynamics (vertically) @tab @code{DynamicLineSpanner}
+@item Dynamics (horizontally) @tab @code{DynamicText}
+@item Fingerings @tab @code{Fingering}
+@item Rehearsal / Text marks @tab @code{RehearsalMark}
+@item Slurs @tab @code{Slur}
+@item Text e.g. @code{^"text"} @tab @code{TextScript}
+@item Ties @tab @code{Tie}
+@item Tuplets @tab @code{TupletBracket}
+@end multitable
+
+
+@node Fixing overlapping notation
+@subsection Fixing overlapping notation
+
+Let's now see how the properties in the previous section can
+help to resolve overlapping notation.
+
+@c FIXME: formatting
+@subheading @code{padding}
+@cindex padding property
+
+The @code{padding} property can be set to increase
+(or decrease) the distance between symbols that are printed
+above or below notes.
+
+@lilypond[quote,fragment,relative=1,verbatim]
+c2\fermata
+\override Script #'padding = #3
+b2\fermata
+@end lilypond
+
+@lilypond[quote,fragment,relative=1,verbatim]
+% This will not work, see below:
+\override MetronomeMark #'padding = #3
+\tempo 4=120
+c1
+% This works:
+\override Score.MetronomeMark #'padding = #3
+\tempo 4=80
+d1
+@end lilypond
+
+Note in the second example how important it is to figure out what
+context handles a certain object. Since the @code{MetronomeMark}
+object
+is handled in the @code{Score} context, property changes in the
+@code{Voice} context will not be noticed. For more details, see
+@ruser{Constructing a tweak}.
+
+If the @code{padding} property of an object is increased when that
+object is in a stack of objects being positioned according to
+their @code{outside-staff-priority}, then that object and all
+objects outside it are moved.
+
+
+@subheading @code{left-padding} and @code{right-padding}
+@cindex left-padding property
+@cindex right-padding property
+
+TODO Example showing the utility of these properties -td
+
+@subheading staff-padding property
+@cindex staff-padding property
+
+@code{staff-padding} can be used to align objects such as dynamics
+along a baseline at a fixed height above the staff, rather than
+at a height dependent on the position of the note to which they
+are attached. It is not a property of
+@code{DynamicText} but of @code{DynamicLineSpanner}.
+This is because the baseline should apply equally to @strong{all}
+dynamics, including those created as extended spanners.
+So this is the way to align the dynamic marks in the example
+taken from the previous section:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=2]
+\dynamicUp
+% Extend width by 1 unit
+\override DynamicText #'extra-spacing-width = #'(-0.5 . 0.5)
+% Align dynamics to a base line 2 units above staff
+\override DynamicLineSpanner #'staff-padding = #2
+a4\f b\mf c\mp b\p
+@end lilypond
+
+
+@subheading self-alignment-X property
+@cindex self-alignment-X property
+
+The following example shows how this can resolve the collision
+of a string fingering object with a note's stem by aligning the
+right edge with the reference point of the parent note:
+
+@lilypond[quote,fragment,ragged-right,verbatim,relative=3]
+\voiceOne
+< a \2 >
+\once \override StringNumber #'self-alignment-X = #RIGHT
+< a \2 >
+@end lilypond
+
+@subheading staff-position property
+@cindex staff-position property
+
+Multimeasure rests in one voice can collide with notes in another.
+Since these rests are typeset centered between the bar lines, it
+would require significant effort for LilyPond to figure out which
+other notes might collide with it, since all the current collision
+handling between notes and between notes and rests is done only
+for notes and rests that occur at the same time. Here's an
+example of a collision of this type:
+
+@lilypond[quote,verbatim,fragment,ragged-right, relative=1]
+<< {c c c c} \\ {R1} >>
+@end lilypond
+
+The best solution here is to move the multimeasure rest down,
+since the rest is in voice two.
+The default in @code{\voiceTwo} (i.e. in the second voice of a
+@code{<<@{...@} \\ @{...@}>>} construct)
+is that @code{staff-position} is set to -4 for MultiMeasureRest,
+so we need to move it, say, four half-staff spaces down to
+@code{-8}.
+
+@lilypond[quote,verbatim,fragment,ragged-right, relative=1]
+<<
+ {c c c c}
+\\
+ \override MultiMeasureRest #'staff-position = #-8
+ {R1}
+>>
+@end lilypond
+
+This is better than using, for example, @code{extra-offset},
+because the ledger line above the rest is inserted automatically.
+
+@subheading extra-offset property
+@cindex extra-offset property
+
+The @code{extra-offset} property provides complete control over the
+positioning of an object both horizontally and vertically.
+
+In the following example, the second fingering is moved a little to
+the left, and 1.8 staff space downwards:
+
+@lilypond[quote,fragment,relative=1,verbatim]
+\stemUp
+f-5
+\once \override Fingering
+ #'extra-offset = #'(-0.3 . -1.8)
+f-5
+@end lilypond
+
+
+@subheading force-hshift property
+@cindex force-hshift property
+@c FIXME: formatting stuff (ie not important right now IMO)
+@c @a nchor Chopin finally corrected TODOgp
+
+We can now see how to apply the final corrections to the Chopin
+example introduced at the end of @ref{I'm hearing Voices}, which
+was left looking like this:
+
+@lilypond[quote,verbatim,fragment,ragged-right]
+\new Staff \relative c'' {
+ \key aes \major
+ <<
+ { c2 aes4. bes8 } \\
+ { aes2 f4 fes } \\
+ { \voiceFour
+ <ees c>2
+ des2
+ }
+ >> |
+ <c ees aes c>1 |
+}
+@end lilypond
+
+@noindent
+The lower two notes of the first chord (i.e,
+those in the third voice) should not be shifted away from the
+note column of the higher two notes. To correct this we set
+@code{force-hshift}, which is a property of
+@code{NoteColumn}, of these notes to zero.
+The lower note of the second chord is best placed just to the
+right of the higher notes. We achieve this by setting
+@code{force-hshift} of this note to 0.5, ie half a note head's
+width to the right of the note column of the higher notes.
+
+Here's the final result:
+
+@lilypond[quote,verbatim,fragment,ragged-right]
+\new Staff \relative c'' {
+ \key aes \major
+ <<
+ { c2 aes4. bes8 } \\
+ { aes2 f4 fes } \\
+ { \voiceFour
+ \once \override NoteColumn #'force-hshift = #0 <ees c>2
+ \once \override NoteColumn #'force-hshift = #0.5 des2
+ }
+ >> |
+ <c ees aes c>1 |
+}
+@end lilypond
+
+
+@subheading positions property
+@cindex positions property
+
+The @code{positions} property allows the position and slope of
+ tuplets, slurs, phrasing slurs and beams to be controlled
+manually. Here's an example which has an ugly phrasing slur
+due to its trying to avoid the slur on the acciaccatura.
+
+@lilypond[quote,verbatim,fragment,ragged-right,relative=1]
+r4 \acciaccatura e8\( d8 c ~c d c d\)
+@end lilypond
+
+@noindent
+We could simply move the phrasing slur above the notes, and this
+would be the preferred solution:
+
+@lilypond[quote,verbatim,fragment,ragged-right,relative=1]
+r4
+\phrasingSlurUp
+\acciaccatura e8\( d8 c ~c d c d\)
+@end lilypond
+
+@noindent
+but if there were some reason why this could not be done the
+other alternative would be to move the left end of the phrasing
+slur down a little using the @code{positions} property. This
+also resolves the rather nasty shape.
+
+@lilypond[quote,verbatim,fragment,ragged-right,relative=1]
+r4
+\once \override PhrasingSlur #'positions = #'(-4 . -3)
+\acciaccatura
+e8\( d8 c ~c d c d\)
+@end lilypond
+
+Here's a further example taken from the opening of the left-hand
+staff of Chopin's Prelude Op 28 No. 2. We see that the beam
+collides with the upper notes:
+
+@lilypond[quote,verbatim,fragment,ragged-right]
+{
+\clef "bass"
+<< {b,8 ais, b, g,} \\ {e, g e, g} >>
+<< {b,8 ais, b, g,} \\ {e, g e, g} >>
+}
+@end lilypond
+
+@noindent
+This can only be resolved by manually moving both ends of the beam
+up from their position at 2 staff-spaces above the center line to,
+say, 3:
+
+@lilypond[quote,verbatim,fragment,ragged-right]
+{
+ \clef "bass"
+ <<
+ \override Beam #'positions = #'(3 . 3)
+ {b,8 ais, b, g,}
+ \\
+ {e, g e, g}
+ >>
+ << {b,8 ais, b, g,} \\ {e, g e, g} >>
+}
+@end lilypond
+
+@noindent
+Note that the override continues to apply in the first voice of
+the second block of quavers, but not to any of the beams in the
+second voice.
+
+@node Real music example
+@subsection Real music example
+
+We end this section on Tweaks by showing the steps to be taken to
+deal with a tricky example which needs several tweaks to produce
+the desired output. The example has been deliberately chosen to
+illustrate the use of the Notation Reference to resolve unusual
+problems with notation. It is not representative of more usual
+engraving process, so please do not let these difficulties put
+you off! Fortunately, difficulties like these are not very common!
+
+The example is from Chopin's Première Ballade, Op. 23, bars 6 to
+9, the transition from the opening Lento to Moderato.
+Here, first, is what we want the output to look like, but to avoid
+over-complicating the example too much we have left out the
+dynamics, fingering and pedalling.
+
+@c The following should appear as music without code
+@lilypond[quote,ragged-right]
+rhMusic = \relative c'' {
+ r2
+ c4.\( g8 |
+ \once \override Tie #'staff-position = #3.5
+ bes1~ |
+ \bar "||"
+ \time 6/4
+ \override Staff.NoteCollision #'merge-differently-headed = ##t
+ \override Staff.NoteCollision #'merge-differently-dotted = ##t
+ bes2.^\markup {\bold "Moderato"} r8
+ <<
+ {c,8[ d fis bes a] | }
+ \\
+ % Reposition the c2 to the right of the merged note
+ {c,8~ \once \override NoteColumn #'force-hshift = #1.0
+ % Move the c2 out of the main note column so the merge will work
+ \shiftOnn c2}
+ \\
+ % Stem on the d2 must be down to permit merging
+ {s8 \stemDown \once \override Stem #'transparent = ##t d2}
+ \\
+ {s4 fis4.}
+ >>
+ \revert Staff.NoteCollision #'merge-differently-headed
+ \revert Staff.NoteCollision #'merge-differently-dotted
+ g2.\)
+}
+
+lhMusic = \relative c' {
+ r2 <c g ees>2( |
+ <d g, d>1)\arpeggio |
+ r2. d,,4 r4 r |
+ r4
+}
+
+\score {
+ \new PianoStaff <<
+ \new Staff = "RH" <<
+ \key g \minor
+ \rhMusic
+ >>
+ \new Staff = "LH" <<
+ \key g \minor
+ \clef "bass"
+ \lhMusic
+ >>
+ >>
+}
+@end lilypond
+
+We note first that the right hand part in the third bar
+requires four voices. These are the five beamed eighth notes,
+the tied C, the half-note D which is merged with the eighth note
+D, and the dotted quarter note F-sharp, which is also merged with
+the eighth note at the same pitch. Everything else is in a single
+voice, so the easiest way is to introduce these four voices
+temporarily at the time they are needed. If you have forgotten
+how to do this, look at @ref{I'm hearing Voices}. Let us begin
+by entering the notes as two variables and setting up the staff
+structure in a score block, and see what LilyPond produces by
+default:
+
+@lilypond[quote,verbatim,ragged-right]
+rhMusic = \relative c'' {
+ r2 c4. g8 |
+ bes1~ |
+ \time 6/4
+ bes2. r8
+ % Start polyphonic section of four voices
+ <<
+ {c,8 d fis bes a | }
+ \\
+ {c,8~ c2 | }
+ \\
+ {s8 d2 | }
+ \\
+ {s4 fis4. | }
+ >>
+ g2.
+}
+
+lhMusic = \relative c' {
+ r2 <c g ees>2 |
+ <d g, d>1 |
+ r2. d,,4 r4 r |
+ r4
+}
+
+\score {
+ \new PianoStaff <<
+ \new Staff = "RH" <<
+ \key g \minor
+ \rhMusic
+ >>
+ \new Staff = "LH" <<
+ \key g \minor
+ \clef "bass"
+ \lhMusic
+ >>
+ >>
+}
+@end lilypond
+
+All the notes are right, but the appearance is far from
+satisfactory. The tie clashes with the change in time signature,
+the beaming in the third bar is wrong, the notes are not
+merged together, and several notation elements are missing.
+Let's first deal with the easier things.
+We can correct the beaming by inserting a beam
+manually, and we can easily add the left hand slur and the right
+hand phrasing slur, since these were all covered in the Tutorial.
+Doing this gives:
+
+@lilypond[quote,verbatim,ragged-right]
+rhMusic = \relative c'' {
+ r2 c4.\( g8 |
+ bes1~ |
+ \time 6/4
+ bes2. r8
+ % Start polyphonic section of four voices
+ <<
+ {c,8[ d fis bes a] | }
+ \\
+ {c,8~ c2 | }
+ \\
+ {s8 d2 | }
+ \\
+ {s4 fis4. | }
+ >>
+ g2.\)
+}
+
+lhMusic = \relative c' {
+ r2 <c g ees>2( |
+ <d g, d>1) |
+ r2. d,,4 r4 r |
+ r4
+}
+
+\score {
+ \new PianoStaff <<
+ \new Staff = "RH" <<
+ \key g \minor
+ \rhMusic
+ >>
+ \new Staff = "LH" <<
+ \key g \minor
+ \clef "bass"
+ \lhMusic
+ >>
+ >>
+}
+@end lilypond
+
+The first bar is now correct. The second bar contains an arpeggio
+and is terminated by a double bar line. How do we do these, as they
+have not been mentioned in this Learning Manual? This is where
+we need to turn to the Notation Reference. Looking up @q{arpeggio}
+and @q{bar line} in the
+index quickly shows us that an arpeggio is produced by appending
+@code{\arpeggio} to a chord, and a double bar line is produced by
+the @code{\bar "||"} command. That's easily done. We next need
+to correct the collision of the tie with the time signature. This
+is best done by moving the tie upwards. Moving objects was covered
+earlier in @ref{Moving objects}, which says that objects positioned
+relative to the staff can be moved by overriding their
+@code{staff-position} property, which is specified in half staff
+spaces relative to the center line of the staff. So the following
+override placed just before the first tied note would move the tie
+up to 3.5 half staff spaces above the center line:
+
+@code{\once \override Tie #'staff-position = #3.5}
+
+This completes bar two, giving:
+
+@lilypond[quote,verbatim,ragged-right]
+rhMusic = \relative c'' {
+ r2 c4.\( g8 |
+ \once \override Tie #'staff-position = #3.5
+ bes1~ |
+ \bar "||"
+ \time 6/4
+ bes2. r8
+ % Start polyphonic section of four voices
+ <<
+ {c,8[ d fis bes a] | }
+ \\
+ {c,8~ c2 | }
+ \\
+ {s8 d2 | }
+ \\
+ {s4 fis4. | }
+ >>
+ g2.\)
+}
+
+lhMusic = \relative c' {
+ r2 <c g ees>2( |
+ <d g, d>1)\arpeggio |
+ r2. d,,4 r4 r |
+ r4
+}
+
+\score {
+ \new PianoStaff <<
+ \new Staff = "RH" <<
+ \key g \minor
+ \rhMusic
+ >>
+ \new Staff = "LH" <<
+ \key g \minor
+ \clef "bass"
+ \lhMusic
+ >>
+ >>
+}
+@end lilypond
+
+On to bar three and the start of the Moderato section. The
+tutorial showed how to add embolded text with the
+@code{\markup} command, so adding @q{Moderato} in bold is easy.
+But how do we merge notes in different voices together? The
+index in the Notation Reference does not mention merging,
+but a search of the text for @q{merge} quickly leads us to
+the overrides for merging differently headed and differently
+dotted notes in @ruser{Collision Resolution}. In our
+example we need to merge both types of note for the duration
+of the polyphonic section in bar 3, so using the information
+in the Notation Reference we add
@example
-\paper @{
- between-system-padding = #0.1
- between-system-space = #0.1
- ragged-last-bottom = ##f
- ragged-bottom = ##f
-@}
+\override Staff.NoteCollision #'merge-differently-headed = ##t
+\override Staff.NoteCollision #'merge-differently-dotted = ##t
@end example
-@item
-You may force the number of systems (i.e., if LilyPond wants
-to typeset some music with 11 systems, you could force it to
-use 10).
+@noindent
+to the start of that section and
@example
-\paper @{
- system-count = #10
-@}
+\revert Staff.NoteCollision #'merge-differently-headed
+\revert Staff.NoteCollision #'merge-differently-dotted
@end example
-@item
-Avoid (or reduce) objects which increase the vertical size of
-a system. For example, volta repeats (or alternate repeats)
-require extra space. If these repeats are spread over two
-systems, they will take up more space than one system with
-the volta repeats and another system without.
-
-Another example is moving dynamics which @q{stick out} of
-a system.
-
-@lilypond[verbatim,quote,fragment]
-\relative c' {
- e4 c g\f c
- \override DynamicLineSpanner #'padding = #-1.8
- \override DynamicText #'extra-offset = #'( -2.1 . 0)
- e4 c g\f c
+@noindent
+to the end, giving:
+
+@lilypond[quote,verbatim,ragged-right]
+rhMusic = \relative c'' {
+ r2 c4.\( g8 |
+ \once \override Tie #'staff-position = #3.5
+ bes1~ |
+ \bar "||"
+ \time 6/4
+ bes2.^\markup {\bold "Moderato"} r8
+ \override Staff.NoteCollision #'merge-differently-headed = ##t
+ \override Staff.NoteCollision #'merge-differently-dotted = ##t
+ % Start polyphonic section of four voices
+ <<
+ {c,8[ d fis bes a] | }
+ \\
+ {c,8~ c2 | }
+ \\
+ {s8 d2 | }
+ \\
+ {s4 fis4. | }
+ >>
+ \revert Staff.NoteCollision #'merge-differently-headed
+ \revert Staff.NoteCollision #'merge-differently-dotted
+ g2.\)
+}
+
+lhMusic = \relative c' {
+ r2 <c g ees>2( |
+ <d g, d>1)\arpeggio |
+ r2. d,,4 r4 r |
+ r4
+}
+
+\score {
+ \new PianoStaff <<
+ \new Staff = "RH" <<
+ \key g \minor
+ \rhMusic
+ >>
+ \new Staff = "LH" <<
+ \key g \minor
+ \clef "bass"
+ \lhMusic
+ >>
+ >>
}
@end lilypond
-@item
-Alter the horizontal spacing via @code{SpacingSpanner}. See
-@ruser{Changing horizontal spacing}, for more details.
+These overrides have merged the two F-sharp notes, but not the two
+on D. Why not? The answer is there in the same section in the
+Notation Reference -- notes being merged must have stems in
+opposite directions and two notes cannot be merged successfully if
+there is a third note in the same note column. Here the two D's
+both have upward stems and there is a third note -- the C. We know
+how to change the stem direction using @code{\stemDown}, and
+the Notation Reference also says how to move the C -- apply a shift
+using one of the @code{\shift} commands. But which one?
+The C is in voice two which has shift off, and the two D's are in
+voices one and three, which have shift off and shift on,
+respectively. So we have to shift the C a further level still
+using @code{\shiftOnn} to avoid it interferring with the two D's.
+Applying these changes gives:
+
+@lilypond[quote,verbatim,ragged-right]
+rhMusic = \relative c'' {
+ r2 c4.\( g8 |
+ \once \override Tie #'staff-position = #3.5
+ bes1~ |
+ \bar "||"
+ \time 6/4
+ bes2.^\markup {\bold "Moderato"} r8
+ \override Staff.NoteCollision #'merge-differently-headed = ##t
+ \override Staff.NoteCollision #'merge-differently-dotted = ##t
+ % Start polyphonic section of four voices
+ <<
+ {c,8[ d fis bes a] | }
+ \\
+ % Move the c2 out of the main note column so the merge will work
+ {c,8~ \shiftOnn c2 | }
+ \\
+ % Stem on the d2 must be down to permit merging
+ {s8 \stemDown d2 | }
+ \\
+ {s4 fis4. | }
+ >>
+ \revert Staff.NoteCollision #'merge-differently-headed
+ \revert Staff.NoteCollision #'merge-differently-dotted
+ g2.\)
+}
+
+lhMusic = \relative c' {
+ r2 <c g ees>2( |
+ <d g, d>1)\arpeggio |
+ r2. d,,4 r4 r |
+ r4
+}
-@lilypond[verbatim,quote]
\score {
- \relative c'' {
- g4 e e2 | f4 d d2 | c4 d e f | g4 g g2 |
- g4 e e2 | f4 d d2 | c4 e g g | c,1 |
- d4 d d d | d4 e f2 | e4 e e e | e4 f g2 |
- g4 e e2 | f4 d d2 | c4 e g g | c,1 |
- }
- \layout {
- \context {
- \Score
- \override SpacingSpanner
- #'base-shortest-duration = #(ly:make-moment 1 4)
- }
- }
+ \new PianoStaff <<
+ \new Staff = "RH" <<
+ \key g \minor
+ \rhMusic
+ >>
+ \new Staff = "LH" <<
+ \key g \minor
+ \clef "bass"
+ \lhMusic
+ >>
+ >>
}
@end lilypond
-@end itemize
+Nearly there. Only two problems remain: The downward stem on the
+merged D should not be there, and the C would be better positioned
+to the right of the D's. We know how to do both of these from the
+earlier tweaks: we make the stem transparent, and move the C with
+the @code{force-hshift} property. Here's the final result:
+
+@lilypond[quote,verbatim,ragged-right]
+rhMusic = \relative c'' {
+ r2
+ c4.\( g8 |
+ \once \override Tie #'staff-position = #3.5
+ bes1~ |
+ \bar "||"
+ \time 6/4
+ bes2.^\markup {\bold "Moderato"} r8
+ \override Staff.NoteCollision #'merge-differently-headed = ##t
+ \override Staff.NoteCollision #'merge-differently-dotted = ##t
+ <<
+ {c,8[ d fis bes a] | }
+ \\
+ % Reposition the c2 to the right of the merged note
+ {c,8~ \once \override NoteColumn #'force-hshift = #1.0
+ % Move the c2 out of the main note column so the merge will work
+ \shiftOnn c2}
+ \\
+ % Stem on the d2 must be down to permit merging
+ {s8 \stemDown \once \override Stem #'transparent = ##t d2}
+ \\
+ {s4 fis4.}
+ >>
+ \revert Staff.NoteCollision #'merge-differently-headed
+ \revert Staff.NoteCollision #'merge-differently-dotted
+ g2.\)
+}
+
+lhMusic = \relative c' {
+ r2 <c g ees>2( |
+ <d g, d>1)\arpeggio |
+ r2. d,,4 r4 r |
+ r4
+}
+\score {
+ \new PianoStaff <<
+ \new Staff = "RH" <<
+ \key g \minor
+ \rhMusic
+ >>
+ \new Staff = "LH" <<
+ \key g \minor
+ \clef "bass"
+ \lhMusic
+ >>
+ >>
+}
+@end lilypond
-@node TODO other name
-@section TODO other name
+
+@node Further tweaking
+@section Further tweaking
@menu
-* Predefined tweaks::
+* Other uses for tweaks::
+* Using variables for tweaks::
+* Other sources of information::
* Advanced tweaks with Scheme::
* Avoiding tweaks with slower processing::
-* The three methods of tweaking::
@end menu
-@node Predefined tweaks
-@subsection Predefined tweaks
+@node Other uses for tweaks
+@subsection Other uses for tweaks
+
+@itemize
+
+@cindex transparent property
+@cindex objects, making invisible
+@cindex removing objects
+@cindex objects, removing
+@cindex hiding objects
+@cindex invisible objects
+
+@item
+Setting the @code{transparent} property will cause an object
+to be printed in @q{invisible ink}: the object is not printed,
+but all its other behavior is retained. The object still takes
+up space, it takes part in collisions, and slurs, ties, and beams
+can be attached to it.
+
+The following example demonstrates how to connect different voices
+using ties. Normally, ties only connect two notes in the same
+voice. By introducing a tie in a different voice,
+
+@lilypond[quote,fragment,relative=2]
+<< {
+ b8~ b8\noBeam
+} \\ {
+ b[ g8]
+} >>
+@end lilypond
+
+@noindent
+and blanking the first up-stem in that voice, the tie appears to cross
+voices:
+
+@lilypond[quote,fragment,relative=2,verbatim]
+<< {
+ \once \override Stem #'transparent = ##t
+ b8~ b8\noBeam
+} \\ {
+ b[ g8]
+} >>
+@end lilypond
+
+To make sure that the just-blanked stem doesn't squeeze the tie too much,
+we also lengthen the stem, by setting the @code{length} to
+@code{8},
+
+@lilypond[quote,fragment,relative=2,verbatim]
+<< {
+ \once \override Stem #'transparent = ##t
+ \once \override Stem #'length = #8
+ b8~ b8\noBeam
+} \\ {
+ b[ g8]
+} >>
+@end lilypond
+
+@cindex stencil property
+
+@item
+For outside-staff objects it is usually better to override the
+object's @code{stencil} property rather than its @code{transparent}
+property when you wish to remove it from the printed output.
+Setting the @code{stencil} property of an object to @code{#f} will
+remove that object entirely from the printed output. This means it
+has no effect on the placement of other objects placed relative to
+it.
+
+For example, if we wished to change the metronome setting in order
+to simulate a fermata in the MIDI output we would not want the
+metronome marking to appear in the printed output, and we would
+not want it to influence the spacing between the two systems or
+the spacing of the notes on the staff. So setting its
+@code{stencil} property to @code{#f} would be the best way.
+We show here the effect of the two methods:
+
+@lilypond[quote,verbatim]
+\score {
+ \relative c'' {
+ % Visible tempo marking
+ \tempo 4=120
+ a4 a a
+ \once \override Score.MetronomeMark #'transparent = ##t
+ % Invisible tempo marking to lengthen fermata note in MIDI
+ \tempo 4=80
+ a\fermata
+ \once \override Score.MetronomeMark #'stencil = ##f
+ % Invisible tempo marking to restore tempo in MIDI
+ \tempo 4=120
+ a a a a
+ }
+ \midi { }
+}
+@end lilypond
+
+@noindent
+Both methods remove the metronome mark from the printed output,
+and both affect the MIDI timing as required, but the first
+(transparent) metronome mark still influences the note spacing
+while the second (with no stencil) does not.
-TODO: Some tweaks are really common, blah blah.
+@end itemize
-for example \slurUp, \fatText.
+@node Using variables for tweaks
+@subsection Using variables for tweaks
-Show example, then explain where to find ly/propert-ly.
+TODO Add section
+@node Other sources of information
+@subsection Other sources of information
The Internals Reference documentation contains a lot of information
about LilyPond, but even more information can be gathered from
looking at the internal LilyPond files.
+TODO Show example, then explain where to find ly/propert-ly.
+
Some default settings (such as the definitions for
@code{\header@{@}}s) are stored as @code{.ly} files. Other
settings (such as the definitions of markup commands) are
We can use Scheme to simply @code{\override} commands,
+TODO Check this is a valid example with skylining
+
@lilypond[quote,verbatim,ragged-right]
padText = #(define-music-function (parser location padding) (number?)
#{
We can use it to create new commands,
+TODO Check this is a valid example with skylining
+
@lilypond[quote,verbatim,ragged-right]
tempoMark = #(define-music-function (parser location padding marktext)
(number? string?)
@end verbatim
-@node The three methods of tweaking
-@subsection The three methods of tweaking
-FIXME write this.
-@verbatim
-\override
-@end verbatim
-@verbatim
-\with {
-}
-@end verbatim
-
-@verbatim
-\layout{ \context
-}}
-@end verbatim
-FIXME discuss \tweak
-FIXME: Move the following words and example into Tweaks or
-somewhere more suitable, leaving just a ref here. -td
-Ways of correcting horizontal placings are described fully
-in the Notation Reference.
-We introduce just one here, the @code{force-hshift} property of
-@code{NoteColumn}. The lower two notes of the first chord (i.e,
-those in the third voice) should not be shifted away from the
-note column of the higher two notes. To correct this we set
-@code{force-hshift} of these notes to zero.
-The lower note of the second chord is best placed just to the
-right of the higher notes. We achieve this by setting
-@code{force-hshift} of this note to 0.5, ie half a notehead's
-width to the right of the note column of the higher notes.
-Here's the final result:
-
-@lilypond[quote,verbatim,fragment,ragged-right]
-\new Staff \relative c'' {
- \key aes \major
- <<
- { c2 aes4. bes8 } \\
- { aes2 f4 fes } \\
- { \voiceFour
- \once \override NoteColumn #'force-hshift = #0 <ees c>2
- \once \override NoteColumn #'force-hshift = #0.5 des2
- }
- >> |
- <c ees aes c>1 |
-}
-@end lilypond
-
-
-
-
-FIXME:
-- There is a section in the manual on \set vs \override (3.3.7),
-which is incomplete. First it doesn't mention \overrideProperty,
-nor does it mention properties which are not capitalized at all.
-And it should explain that \override should be used to set
-properties with hyphenated names, like auto-knee-gap. (I had to
-experiment to find out how to do this.)
-
-
-FIXME: moved from fundamental, dumped here at random.
-
-@lilypond[verbatim,quote,ragged-right]
-\new Staff = "main" {
- \relative g' {
- r4 g8 g c4 c8 d |
- e4
- << % Start main and ossia in parallel
- { r8 f c c } % Main music
- \new Staff \with { % Start ossia staff
- \remove "Clef_engraver"
- \remove "Time_signature_engraver"
- % Reduce size of notes and staff
- fontSize = #-2
- \override StaffSymbol #'staff-space = #(magstep -2)
- alignAboveContext = "main" % Place above main staff
- }
- { s8 f f c } % Ossia music
- >> % End parallel music
- r4 |
- }
-}
-@end lilypond
projects / lilypond.git / blobdiff