@c -*- coding: utf-8; mode: texinfo; -*- @c This file is part of lilypond-learning.tely @ignore Translation of GIT committish: FILL-IN-HEAD-COMMITTISH When revising a translation, copy the HEAD committish of the version that you are working on. See TRANSLATION for details. @end ignore @c \version "2.11.51" @node Tweaking output @chapter Tweaking output This chapter discusses how to modify output. LilyPond is extremely configurable; virtually every fragment of output may be changed. @menu * Tweaking basics:: * The Internals Reference manual:: * 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. In this section we cover the basic concepts required to understand 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 Properties contained within them are fundamental to understanding and constructing Tweaks. @node Objects and interfaces @subsection Objects and interfaces @cindex objects @cindex grobs @cindex spanners @cindex interfaces Tweaking involves modifying the internal operation and structures of the LilyPond program, so we must first introduce some terms which are used to describe those internal operations and structures. The term @q{Object} is a generic term used to refer to the multitude of internal structures built by LilyPond during the processing of an input file. So when a command like @code{\new Staff} is encountered a new object of type @code{Staff} is constructed. That @code{Staff} object then holds all the 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 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 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, such as their position, size, color, etc. Some layout objects are still more specialized. Phrasing slurs, crescendo hairpins, ottava marks, and many other grobs are not localized in a single place -- they have a starting point, an ending point, and maybe other properties concerned with their shape. Objects with an extended shape like these are called @q{Spanners}. It remains to explain what @q{Interfaces} are. Many objects, even though they are quite different, share common features which need to be processed in the same way. For example, all grobs have a color, a size, a position, etc, and all these properties are processed in the same way during LilyPond's interpretation of the input file. To simplify these internal operations these common actions and properties are grouped together in an object called a @code{grob-interface}. There are many other groupings of common properties like this, each one given a name ending in @code{interface}. In total there are over 100 such interfaces. We shall see later why this is of interest and use to the user. These, then, are the main terms relating to objects which we shall use in this chapter. @node Naming conventions of objects and properties @subsection Naming conventions of objects and properties We met some object naming conventions previously, in @ref{Contexts and engravers}. Here for reference is a list 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 capitalized 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/property type @tab Naming convention @tab Example @item Contexts @tab Aaaa or AaaaAaaaAaaa @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 @item Interfaces @tab aaa-aaa-interface @tab grob-interface, break-aligned-interface @item Context Properties @tab aaa or aaaAaaaAaaa @tab alignAboveContext, skipBars @item Layout Object Properties @tab aaa or aaa-aaa-aaa @tab direction, beam-thickness @end multitable As we shall see shortly, the properties of different types of object are modified by different commands, so it is useful to be able to recognize the type of object from the names of its properties. @node Tweaking methods @subsection Tweaking methods @strong{\override command} @cindex override command @funindex \override We have already met the commands @code{\set} and @code{\with}, used to change the properties of @strong{contexts} and to remove and add @strong{engravers}, in @ref{Modifying context properties} and @ref{Adding and removing engravers}. We now must meet some more important commands. The command to change the properties of @strong{layout objects} is @code{\override}. Because this command has to modify internal properties deep within LilyPond its syntax is not as simple as the commands you have met so far. It needs to know precisely which property of which object in which context has to be modified, and what its new value is to be. Let's see how this is done. The general syntax of this command is: @example \override @emph{context}.@emph{layout_object} #'@emph{layout_property} = #@emph{value} @end example @noindent This will set the property with the name @emph{layout_property} of the layout object with the name @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. Later sections deal comprehensively with properties and their values, but to illustrate the format and use of these commands we shall use just a few simple properties and values which are easily understood. 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 most common command used in tweaking, and most of the rest of this chapter will be directed to presenting examples of how it is used. Here is a simple example to change the color of the note head: @lilypond[quote,fragment,ragged-right,verbatim,relative=1] c d \override NoteHead #'color = #red e f g \override NoteHead #'color = #green a b c @end lilypond @strong{\revert command} @cindex revert command @funindex \revert Once overridden, the property retains its new value until it is overridden again or a @code{\revert} command is encountered. The @code{\revert} command has the following syntax and causes the value of the property to revert to its original default value; note, not its previous value if several @code{\override} commands have been issued. @example \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. Here we revert the color of the note head to the default value for the final two notes: @lilypond[quote,fragment,ragged-right,verbatim,relative=1] c d \override NoteHead #'color = #red e f g \override NoteHead #'color = #green a \revert NoteHead #'color b c @end lilypond @strong{\once prefix} Both the @code{\override} and the @code{\set} commands may be prefixed by @code{\once}. This causes the following @code{\override} or @code{\set} command to be effective only during the current musical moment before the property reverts back to its default value. Using the same example, we can change the color of a single note like this: @lilypond[quote,fragment,ragged-right,verbatim,relative=1] c d \once \override NoteHead #'color = #red e f g \once \override NoteHead #'color = #green a b c @end lilypond @strong{\overrideProperty command} @cindex overrideProperty command @funindex \overrideProperty There is another form of the override command, @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 @strong{\tweak command} @cindex tweak command @funindex \tweak The final tweaking command which is available is @code{\tweak}. 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. Here's an example. Suppose we wish to change the size of the middle note (the E) in a C major chord. Let's first see what @code{\once \override} would do: @lilypond[quote,fragment,ragged-right,verbatim,relative=1] 4 \once \override NoteHead #'font-size = #-3 @end lilypond We see the override affects @emph{all} the notes in the chord. This is because all the notes of a chord occur at the same @emph{musical moment}, and the action of @code{\once} is to apply the override to all layout objects of the type specified which occur at the same musical moment as the @code{\override} command itself. The @code{\tweak} command operates in a different way. It acts on the immediately following item in the input stream. However, it is effective only on objects which are created directly from the input stream, essentially note heads and articulations. (Objects such as stems and accidentals are created later and cannot be tweaked in this way). Furthermore, when it is applied to note heads these @emph{must} be within a chord, i.e., within single angle brackets, so to tweak a single note the @code{\tweak} command must be placed inside single angle brackets with the note. So to return to our example, the size of the middle note of a chord would be changed in this way: @lilypond[quote,fragment,ragged-right,verbatim,relative=1] 4 4 @end lilypond Note that the syntax of @code{\tweak} is different from that of the @code{\override} command. Neither the context nor the layout object should be specified; in fact, it would generate an error to do so. These are both implied by the following item in the input stream. So the general syntax of the @code{\tweak} command is simply: @example \tweak #'@emph{layout_property} = #@emph{value} @end example A @code{\tweak} command can also be used to modify just one in a series of articulations, as shown here: @lilypond[quote,fragment,ragged-right,verbatim,relative=2] a ^Black -\tweak #'color #red ^Red -\tweak #'color #green _Green @end lilypond Note that the @code{\tweak} command must be preceded by an articulation mark as if it were an articulation itself. @cindex tuplets, nested @cindex triplets, nested @cindex bracket, tuplet @cindex tuplet bracket @cindex triplet bracket @funindex TupletBracket The @code{\tweak} command must also be used to change the appearance of one of a set of nested tuplets which begin at the same musical moment. In the following example, the long tuplet bracket and the first of the three short brackets begin at the same musical moment, so any @code{\override} command would apply to both of them. In the example, @code{\tweak} is used to distinguish between them. The first @code{\tweak} command specifies that the long tuplet bracket is to be placed above the notes and the second one specifies that the tuplet number is to be printed in red on the first short tuplet bracket. @lilypond[quote,ragged-right,verbatim,fragment,relative=2] \tweak #'direction #up \times 4/3 { \tweak #'color #red \times 2/3 { c8[ c8 c8] } \times 2/3 { c8[ c8 c8] } \times 2/3 { c8[ c8 c8] } } @end lilypond You can find more details of the @code{\tweak} command in @ruser{Objects connected to the input}. If nested tuplets do not begin at the same moment their appearance may be modified in the usual way with @code{\override} commands: @c NOTE Tuplet brackets collide if notes are high on staff @c See issue 509 @lilypond[quote,ragged-right,verbatim,fragment,relative=1] \times 2/3 { c8[ c c]} \once \override TupletNumber #'text = #tuplet-number::calc-fraction-text \times 2/3 { c[ c] c[ c] \once \override TupletNumber #'transparent = ##t \times 2/3 { c8[ c c] } \times 2/3 { c8[ c c]} } @end lilypond @node The Internals Reference manual @section The Internals Reference manual @cindex Internals Reference @menu * Properties of layout objects:: * Properties found in interfaces:: * Types of properties:: @end menu @node Properties of layout objects @subsection Properties of layout objects @cindex properties of layout objects @cindex properties of grobs @cindex grobs, properties of @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 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 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. Before we look at the Internals Reference a word of warning. 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 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. @cindex override example @cindex Internals Reference, example of using Let's use a concrete example with a simple fragment of real music: @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 } } @end lilypond Suppose now that we decide we would like the slurs to be a little heavier. Is this possible? The slur is certainly a layout object, so the question is, @q{Is there a property belonging to a slur which controls the heaviness?} To answer 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 @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 paragraphs to make sense you will need to actually do this as you read. Under the heading @strong{Top} you will see five links. Select the link to the @emph{Backend}, which is where information about layout objects is to be found. There, under the heading @strong{Backend}, select the link to @emph{All layout objects}. The page that appears lists all the layout objects used in your version of LilyPond, in alphabetic order. Select the link to Slur, and the properties of Slurs are listed. (An alternative way of finding this page is from the Notation Reference. On one of the pages that deals with slurs you may find a link to the Internals Reference. This link will take you directly to this page, but often it is easier to go straight to the IR and search there.) This Slur page in the IR tells us first that Slur objects are created by the Slur_engraver. Then it lists the standard settings. Note these are @strong{not} in alphabetic order. Browse down them looking for a property that might control the heaviness of slurs, and you should find @example @code{thickness} (number) @code{1.2} Line thickness, generally measured in @code{line-thickness} @end example 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}. As we said earlier, there are few to no explanations in the IR, but we already have enough information to try changing the slur thickness. We see that the name of the layout object is @code{Slur}, that the name of the property to change is @code{thickness} and that the new value should be a number somewhat larger than 1.2 if we are to make slurs thicker. We can now construct the @code{\override} command by simply 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 Slur #'thickness = #5.0 @end example Don't forget the @code{#'} preceding the property name and and @code{#} preceding the new value! 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 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 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 } } @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, @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 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 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 } } @end lilypond @noindent Now only the first slur is made heavier. The @code{\once} command can also be used before the @code{\set} command. @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 the slurs begin: @lilypond[quote,fragment,ragged-right,verbatim,relative=2] { \time 6/8 { r4 b8 % Increase thickness of immediately following slur only \once \override Slur #'thickness = #5.0 b[( g]) g | % Increase thickness of immediately following slur only \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 } } @end lilypond @noindent or we could omit the @code{\once} command and use the @code{\revert} command to return the @code{thickness} property to its default value after the second slur: @lilypond[quote,fragment,ragged-right,verbatim,relative=2] { \time 6/8 { r4 b8 % Increase thickness of all following slurs from 1.2 to 5.0 \override Slur #'thickness = #5.0 b[( g]) g | g[( e]) % Revert thickness of all following slurs to default of 1.2 \revert Slur #'thickness e d[( f]) a | a g } \addlyrics { The man who feels love's sweet e -- mo -- tion } } @end lilypond @noindent The @code{\revert} command can be used to return any property changed with @code{\override} back to its default value. You may use whichever method best suits what you want to do. That concludes our introduction to the IR, and the basic method of tweaking. Several examples follow in the later 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 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{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 LyricText. At the bottom of the page is a list of clickable (in the html versions 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 @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 differently 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 arbitrary 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 \override LyricText #'font-shape = #'italic @end example @noindent 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 { 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 } } @end lilypond @noindent and the lyrics are all printed in italics. @subheading Specifying the 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 recognize them. So the command should be: @example \override Lyrics . LyricText #'font-shape = #'italic @end example @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 apostrophe-hash, @code{'#}. @tab @code{'#(#t #t #f)} @end multitable @node Appearance of objects @section Appearance of objects Let us now put what we have learned into practice with a few examples which show how tweaks may be used to change the appearance of the printed music. @menu * Visibility and color of objects:: * Size of objects:: * Length and thickness of objects:: @end menu @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}: @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 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] { \time 12/16 \override Staff.BarLine #'stencil = ##f c4 b8 c d16 c d8 | g, a16 b8 c d4 e16 | e8 } @end lilypond Now the bar lines have vanished. @subheading break-visibility @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 @code{#'#} before the opening bracket. The @code{'#} is required as part of the value to introduce a vector, and the first @code{#} is required, as always, to precede the value itself in the @code{\override} command. @lilypond[quote,fragment,ragged-right,verbatim,relative=2] { \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 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] { \time 12/16 \override Staff.TimeSignature #'transparent = ##t c4 b8 c d16 c d8 | g, a16 b8 c d4 e16 | e8 } @end lilypond @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] { \time 12/16 \override Staff.TimeSignature #'stencil = ##f c4 b8 c d16 c d8 | g, a16 b8 c d4 e16 | e8 } @end lilypond @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} colors 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] { \time 12/16 \override Staff.BarLine #'color = #white c4 b8 c d16 c d8 | g, a16 b8 c d4 e16 | e8 } @end lilypond @noindent 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: @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 @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. @cindex rgb colors @cindex color, rgb 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 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 @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 Size of objects @subsection Size of objects 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}. @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 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: @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 where the extra pair of braces after the @code{\with} clause are required to ensure the enclosed overrides 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 synchronized 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 @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 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 @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}). @example \set fontSize = #-2 @end example 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%. Let's try it in our ossia 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" \override Clef #'stencil = ##f \override TimeSignature #'stencil = ##f % Reduce all font sizes by ~24% fontSize = #-2 } { f8 f c } >> r4 | } } @end lilypond 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. @node Length and thickness of objects @subsection Length and thickness of objects @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,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 @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 synchronized 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 @menu * Automatic behavior:: * Within-staff objects:: * Outside staff objects:: @end menu @node Automatic behavior @subsection Automatic behavior 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 behavior, 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 explicitly set). Note that @q{Text3} is automatically positioned close to the staff again, nestling under @q{Text2}. @lilypond[quote,fragment,ragged-right,verbatim,relative=2] c2^"Text1" c^"Text2" c^"Text3" c^"Text4" @end lilypond 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 @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 behavior. This can be done for whole sections of music or even for an individual note. The property which controls this behavior 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 behavior 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 behavior. @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 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 .25 .35 @headitem Down/Left @tab Up/Right @tab Revert @tab Effect @item @code{\arpeggioArrowDown} @tab @code{\arpeggioArrowUp} @tab @code{\arpeggioNormal} @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. @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 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,ragged-right,verbatim,relative=2] @end lilypond 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 @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 constraints 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) < c-1 e-2 g-3 b-5 > 4 \set fingeringOrientations = #'(left) < c-1 e-2 g-3 b-5 > 4 \set fingeringOrientations = #'(up left down) < c-1 e-2 g-3 b-5 > 4 \set fingeringOrientations = #'(up left) < c-1 e-2 g-3 b-5 > 4 \set fingeringOrientations = #'(right) < 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) < c-1 e-2 g-3 b-5 > 4 \set fingeringOrientations = #'(left) < c-1 e-2 g-3 b-5 > 4 \set fingeringOrientations = #'(up left down) < c-1 e-2 g-3 b-5 > 4 \set fingeringOrientations = #'(up left) < c-1 e-2 g-3 b-5 > 4 \set fingeringOrientations = #'(right) < 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 \ottava #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 \ottava #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} do 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 \ottava #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 \ottava #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 behavior, above (see @ref{Automatic behavior}). 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. @subheading \textLengthOn @funindex \textLengthOn @cindex notes, spreading out with text 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 behavior, 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 behavior 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 honored c''2 @end lilypond @subheading Dynamics 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 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 @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. In the type-setting process the note heads are type-set first and then the accidentals, if any, are added to the left of the note heads using the @code{right-padding} property to determine the separation from the note heads. So only the @code{right-padding} property of the @code{AccidentalPlacement} object has any effect on the placement of the accidentals. 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 honor 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 occurring 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 @item Finally, when all else fails, objects may be manually repositioned relative to the staff center line vertically, 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 @end enumerate A particular object may not have all of these properties. It is necessary to go to the IR to look up which properties are available for the object in question. 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. @subheading padding property @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{Modifying properties}. 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 left-padding and right-padding @cindex left-padding property @cindex right-padding property The @code{right-padding} property affects the spacing between the accidental and the note to which it applies. It is not often required, but the following example shows one situation where it is needed. Suppose we wish to show a chord containing both a B-natural and a B-flat. To avoid ambiguity we would like to precede the notes with both a natural and a flat sign. Here are a few attempts to do this: @lilypond[quote,fragment,ragged-right,verbatim,relative=2] @end lilypond None work, with the second two showing bad collisions between the two signs. One way of achieving this is to override the accidental stencil with a markup containing the natural and flat symbols in the order we would like, like this: @lilypond[quote,ragged-right,verbatim] naturalplusflat = \markup { \natural \flat } \relative c'' { \once \override Accidental #'stencil = #ly:text-interface::print \once \override Accidental #'text = #naturalplusflat \once \override Score.AccidentalPlacement #'right-padding = #1.5 } @end lilypond @noindent This necessarily uses an override for the accidental stencil which will not be covered until later. The stencil type must be a procedure, here changed to print the contents of the @code{text} property of @code{Accidental}, which itself is set to be a natural sign followed by a flat sign. These are then moved further away from the note head by overriding @code{right-padding}. @noindent @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 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 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. @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 2 des2 } >> | 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 2 \once \override NoteColumn #'force-hshift = #0.5 des2 } >> | 1 | } @end lilypond @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.\( g8 | \once \override Tie #'staff-position = #3.5 bes1~ | \bar "||" \time 6/4 \mergeDifferentlyHeadedOn \mergeDifferentlyDottedOn bes2.^\markup {\bold "Moderato"} r8 << {c,8[ d fis bes a] | } \\ % Reposition the c2 to the right of the merged note {c,8~ \once \override NoteColumn #'force-hshift = #1.0 % Move the c2 out of the main note column so the merge will work \shiftOnn c2} \\ % Stem on the d2 must be down to permit merging {s8 \stemDown \once \override Stem #'transparent = ##t d2} \\ {s4 fis4.} >> \mergeDifferentlyHeadedOff \mergeDifferentlyDottedOff g2.\) } lhMusic = \relative c' { r2 2( | 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 2 | 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 2( | 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 2( | 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? This is where we need to turn to the Notation Reference for help. A search for @qq{merge} in the Notation Reference index quickly leads us to the commands 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 we find in the Notation Reference we add @example \mergeDifferentlyHeadedOn \mergeDifferentlyDottedOn @end example @noindent to the start of that section and @example \mergeDifferentlyHeadedOff \mergeDifferentlyDottedOff @end example @noindent to the end, giving: @lilypond[quote,verbatim,ragged-right] rhMusic = \relative c'' { r2 c4.\( g8 | \once \override Tie #'staff-position = #3.5 bes1~ | \bar "||" \time 6/4 bes2.^\markup {\bold "Moderato"} r8 \mergeDifferentlyHeadedOn \mergeDifferentlyDottedOn % Start polyphonic section of four voices << {c,8[ d fis bes a] | } \\ {c,8~ c2 | } \\ {s8 d2 | } \\ {s4 fis4. | } >> \mergeDifferentlyHeadedOff \mergeDifferentlyDottedOff g2.\) } lhMusic = \relative c' { r2 2( | 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 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 interfering with the two D's. Applying these changes gives: @lilypond[quote,verbatim,ragged-right] rhMusic = \relative c'' { r2 c4.\( g8 | \once \override Tie #'staff-position = #3.5 bes1~ | \bar "||" \time 6/4 bes2.^\markup {\bold "Moderato"} r8 \mergeDifferentlyHeadedOn \mergeDifferentlyDottedOn % Start polyphonic section of four voices << {c,8[ d fis bes a] | } \\ % Move the c2 out of the main note column so the merge will work {c,8~ \shiftOnn c2 | } \\ % Stem on the d2 must be down to permit merging {s8 \stemDown d2 | } \\ {s4 fis4. | } >> \mergeDifferentlyHeadedOff \mergeDifferentlyDottedOff g2.\) } lhMusic = \relative c' { r2 2( | 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 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.\( g8 | \once \override Tie #'staff-position = #3.5 bes1~ | \bar "||" \time 6/4 bes2.^\markup {\bold "Moderato"} r8 \mergeDifferentlyHeadedOn \mergeDifferentlyDottedOn << {c,8[ d fis bes a] | } \\ % Reposition the c2 to the right of the merged note {c,8~ \once \override NoteColumn #'force-hshift = #1.0 % Move the c2 out of the main note column so the merge will work \shiftOnn c2} \\ % Stem on the d2 must be down to permit merging {s8 \stemDown \once \override Stem #'transparent = ##t d2} \\ {s4 fis4.} >> \mergeDifferentlyHeadedOff \mergeDifferentlyDottedOff g2.\) } lhMusic = \relative c' { r2 2( | 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 Further tweaking @section Further tweaking @menu * Other uses for tweaks:: * Using variables for tweaks:: * Other sources of information:: * Avoiding tweaks with slower processing:: * Advanced tweaks with Scheme:: @end menu @node Other uses for tweaks @subsection Other uses for tweaks @cindex transparent property, use of @cindex objects, making invisible @cindex removing objects @cindex objects, removing @cindex hiding objects @cindex invisible objects @cindex tying notes across voices @subheading Tying notes across voices The following example demonstrates how to connect notes in different voices using ties. Normally, only two notes in the same voice can be connected with ties. By using two voices, with the tied notes in one of them @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 can 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 @subheading Simulating a fermata in MIDI @cindex stencil property, use of @cindex fermata, implementing in MIDI 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 markings to appear in the printed output, and we would not want it to influence the spacing between the two systems or the positions of adjacent annotations 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,ragged-right] \score { \relative c'' { % Visible tempo marking \tempo 4=120 a4 a a \once \override Score.MetronomeMark #'transparent = ##t % Invisible tempo marking to lengthen fermata in MIDI \tempo 4=80 a\fermata % New tempo for next section \tempo 4=100 a a a a } \layout { } \midi { } } @end lilypond @lilypond[quote,verbatim,ragged-right] \score { \relative c'' { % Visible tempo marking \tempo 4=120 a4 a a \once \override Score.MetronomeMark #'stencil = ##f % Invisible tempo marking to lengthen fermata in MIDI \tempo 4=80 a\fermata % New tempo for next section \tempo 4=100 a a a a } \layout { } \midi { } } @end lilypond @noindent Both methods remove the metronome mark which lengthens the fermata from the printed output, and both affect the MIDI timing as required, but the transparent metronome mark in the first line forces the following tempo indication too high while the second (with the stencil removed) does not. @node Using variables for tweaks @subsection Using variables for tweaks Override commands are often long and tedious to type, and they have to be absolutely correct. If the same overrides are to be used many times it may be worth defining variables to hold them. Suppose we wish to emphasize certain words in lyrics by printing them in bold italics. The @code{\italic} and @code{\bold} commands only work within lyrics if they are also embedded in @code{\markup}, which makes them tedious to enter, so as an alternative can we instead use the @code{\override} and @code{\revert} commands? @example @code{\override Lyrics . LyricText #'font-shape = #'italic} @code{\override Lyrics . LyricText #'font-series = #'bold} @code{\revert Lyrics . LyricText #'font-shape} @code{\revert Lyrics . LyricText #'font-series} @end example These would also be extremely tedious to enter if there were many words requiring emphasis. So instead we define these as two variables, and use them as follows, although normally we would perhaps choose shorter names for the variables to make them quicker to type: @lilypond[quote,verbatim] emphasize = { \override Lyrics . LyricText #'font-shape = #'italic \override Lyrics . LyricText #'font-series = #'bold } normal = { \revert Lyrics . LyricText #'font-shape \revert Lyrics . LyricText #'font-series } global = { \time 4/4 \partial 4 \key c \major} SopranoMusic = \relative c' { c4 | e4. e8 g4 g | a a g } AltoMusic = \relative c' { c4 | c4. c8 e4 e | f f e } TenorMusic = \relative c { e4 | g4. g8 c4. b8 | a8 b c d e4 } BassMusic = \relative c { c4 | c4. c8 c4 c | f8 g a b c4 } VerseOne = \lyrics { E -- | ter -- nal \emphasize Fa -- ther, \normal | strong to save, } VerseTwo = \lyricmode { O | \emphasize Christ, \normal whose voice the | wa -- ters heard, } VerseThree = \lyricmode { O | \emphasize Ho -- ly Spi -- rit, \normal | who didst brood } VerseFour = \lyricmode { O | \emphasize Tri -- ni -- ty \normal of | love and pow'r } \score { \new ChoirStaff << \new Staff << \clef "treble" \new Voice = "Soprano" { \voiceOne \global \SopranoMusic } \new Voice = "Alto" { \voiceTwo \AltoMusic } \new Lyrics \lyricsto "Soprano" { \VerseOne } \new Lyrics \lyricsto "Soprano" { \VerseTwo } \new Lyrics \lyricsto "Soprano" { \VerseThree } \new Lyrics \lyricsto "Soprano" { \VerseFour } >> \new Staff << \clef "bass" \new Voice = "Tenor" { \voiceOne \TenorMusic } \new Voice = "Bass" { \voiceTwo \BassMusic } >> >> } @end lilypond @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 by looking at the internal LilyPond files. To explore these, you must first find the directory appropriate to your system. The location of this directory depends (a) on whether you obtained LilyPond by downloading a precompiled binary from lilypond.org or whether you installed it from a package manager (i.e. distributed with Linux, or installed under fink or cygwin) or compiled it from source, and (b) on which operating system it is being used: @strong{Downloaded from lilypond.org} @itemize @bullet @item Linux Navigate to @file{@var{INSTALLDIR}/lilypond/usr/share/lilypond/current/} @item MacOS X Navigate to @file{@var{INSTALLDIR}/LilyPond.app/Contents/Resources/share/lilypond/current/} by either @code{cd}-ing into this directory from the Terminal, or control-clicking on the LilyPond application and selecting @q{Show Package Contents}. @item Windows Using Windows Explorer, navigate to @file{@var{INSTALLDIR}/LilyPond/usr/share/lilypond/current/} @end itemize @strong{Installed from a package manager or compiled from source} Navigate to @file{@var{PREFIX}/share/lilypond/@var{X.Y.Z}/}, where @var{PREFIX} is set by your package manager or @code{configure} script, and @var{X.Y.Z} is the LilyPond version number. @smallspace Within this directory the two interesting subdirectories are @itemize @item @file{ly/} - contains files in LilyPond format @item @file{scm/} - contains files in Scheme format @end itemize Let's begin by looking at some files in @file{ly/}. Open @file{ly/property-init.ly} in a text editor. The one you normally use for @code{.ly} files will be fine. This file contains the definitions of all the standard LilyPond built-in commands, such as @code{\stemUp} and @code{\slurDotted}. You will see that these are nothing more than definitions of variables containing one or a group of @code{\override} commands. For example, @code{/tieDotted} is defined to be: @example tieDotted = @{ \override Tie #'dash-period = #0.75 \override Tie #'dash-fraction = #0.1 @} @end example If you do not like the default values these built-in commands can be redefined easily, just like any other variable, at the head of your input file. The following are the most useful files to be found in @file{ly/}: @multitable @columnfractions .4 .6 @headitem Filename @tab Contents @item @file{ly/engraver-init.ly} @tab Definitions of engraver Contexts @item @file{ly/paper-defaults.ly} @tab Specifications of paper-related defaults @item @file{ly/performer-init.ly} @tab Definitions of performer Contexts @item @file{ly/property-init.ly} @tab Definitions of all common built-in commands @end multitable Other settings (such as the definitions of markup commands) are stored as @code{.scm} (Scheme) files. The Scheme programming language is used to provide a programmable interface into LilyPond internal operation. Further explanation of these files is currently outside the scope of this manual, as a knowledge of the Scheme language is required. Users should be warned that a substantial amount of technical knowledge or time is required to understand Scheme and these files (see @ref{Scheme tutorial}). If you have this knowledge, the Scheme files which may be of interest are: @multitable @columnfractions .4 .6 @headitem Filename @tab Contents @item @file{scm/auto-beam.scm} @tab Sub-beaming defaults @item @file{scm/define-grobs.scm} @tab Default settings for grob properties @item @file{scm/define-markup-commands.scm} @tab Specify all markup commands @item @file{scm/midi.scm} @tab Default settings for MIDI output @item @file{scm/output-lib.scm} @tab Settings that affect appearance of frets, colors, accidentals, bar lines, etc @item @file{scm/parser-clef.scm} @tab Definitions of supported clefs @item @file{scm/script.scm} @tab Default settings for articulations @end multitable @node Avoiding tweaks with slower processing @subsection Avoiding tweaks with slower processing LilyPond can perform extra checks while it processes input files. These checks will take extra time to perform, but fewer manual tweaks may be required to obtain an acceptable result. If a text script or part of the lyrics extends over the margins these checks will compress that line of the score just enough to fit within the margins. To be effective under all circumstances these checks must be enabled by placing the overrides in a Score @code{\with} block, rather than in-line in music, as follows: @example \new Score \with @{ % Makes sure text scripts and lyrics are within the paper margins \override PaperColumn #'keep-inside-line = ##t \override NonMusicalPaperColumn #'keep-inside-line = ##t @} @{ .. @} @end example @node Advanced tweaks with Scheme @subsection Advanced tweaks with Scheme Although many things are possible with the @code{\override} and @code{\tweak} commands, an even more powerful way of modifying the action of LilyPond is available through a programmable interface to the LilyPond internal operation. Code written in the Scheme programming language can be incorporated directly in the internal operation of LilyPond. Of course, at least a basic knowledge of programming in Scheme is required to do this, and an introduction is provided in the @ref{Scheme tutorial}. As an illustration of one of the many possibilities, instead of setting a property to a constant it can be set to a Scheme procedure which is then called whenever that property is accessed by LilyPond. The property can then be set dynamically to a value determined by the procedure at the time it is called. In this example we color the note head in accordance with its position on the staff. @lilypond[quote,verbatim,ragged-right] #(define (color-notehead grob) "Color the notehead according to its position on the staff." (let ((mod-position (modulo (ly:grob-property grob 'staff-position) 7))) (case mod-position ;; Return rainbow colors ((1) (x11-color 'red )) ; for C ((2) (x11-color 'orange )) ; for D ((3) (x11-color 'yellow )) ; for E ((4) (x11-color 'green )) ; for F ((5) (x11-color 'blue )) ; for G ((6) (x11-color 'purple )) ; for A ((0) (x11-color 'violet )) ; for B ) ) ) \relative c' { % Arrange to obtain color from color-notehead procedure \override NoteHead #'color = #color-notehead c2 c' | b4 g8 a b4 c | c,2 a' | g1 | } \addlyrics { Some -- where o -- ver the Rain -- bow, way up high, } @end lilypond Further examples showing the use of these programmable interfaces can be found in @ref{Tweaking with Scheme}.