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2 @c This file is part of lilypond-learning.tely
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11 @chapter Tweaking output
13 This chapter discusses how to modify output. LilyPond is extremely
14 configurable; virtually every fragment of output may be changed.
16 TODO: This chapter is still under development and this version is
17 somewhat experimental; nothing is fixed. Don't translate yet!
23 * The Internals Reference manual::
24 * Appearance of objects::
25 * Placement of objects::
26 * Collisions of objects::
32 @section Tweaking basics
35 * Introduction to tweaks::
36 * Objects and interfaces::
37 * Naming conventions of objects and properties::
41 @node Introduction to tweaks
42 @subsection Introduction to tweaks
44 @q{Tweaking} is a LilyPond term for the various methods available
45 to the user for modifying the actions taken during interpretation
46 of the input file and modifying the appearance of the printed
47 output. Some tweaks are very easy to use; others are more
48 complex. But taken together the methods available for tweaking
49 permit almost any desired appearance of the printed music to be
52 In this section we cover the basic concepts required to understand
53 tweaking. Later we give a variety of potted commands which can
54 simply be copied to obtain the same effect in your own scores, and
55 at the same time we show how these commands may be constructed so
56 that you may learn how to develop your own tweaks.
58 Before starting on this Chapter you may wish to review the section
59 @ref{Contexts and engravers}, as Contexts, Engravers, and the
60 Properties contained within them are fundamental to understanding
61 and constructing Tweaks.
63 @node Objects and interfaces
64 @subsection Objects and interfaces
71 Tweaking involves modifying the internal operation and structures
72 of the LilyPond program, so we must first introduce some terms
73 which are used to describe those internal operations and
76 The term @q{Object} is a generic term used to refer to the
77 multitude of internal structures built by LilyPond during the
78 processing of an input file. So when a command like @code{\new
79 Staff} is encountered a new object of type @code{Staff} is
80 constructed. That @code{Staff} object then holds all the
81 properties associated with that particular staff, for example, its
82 name and its key signature, together with details of the engravers
83 which have been assigned to operate within that staff's context.
84 Similarly, there are @code{Voice} objects, @code{Score} objects,
85 @code{Lyric} objects, and objects to represent barlines,
86 noteheads, ties, dynamics, etc, each with their own set of
89 Some types of object are given special names. Objects which
90 represent items of notation on the printed output such as
91 noteheads, stems, slurs, ties, fingering, clefs, etc are called
92 @q{Layout objects}, often known as @q{Graphical Objects}, or
93 @q{Grobs} for short. These are still objects in the generic sense
94 above, and so they too all have properties associated with them,
95 such as their position, size, color, etc.
97 Some layout objects are still more specialised. Phrasing slurs,
98 crescendo hairpins, ottavo marks, and many other grobs are not
99 localised in a single place -- they have a starting point, an
100 ending point, and maybe other properties concerned with their
101 shape. Objects with an extended shape like these are called
104 It remains to explain what @q{Interfaces} are. Many objects,
105 even though they are quite different, share common features
106 which need to be processed in the same way.
107 For example, all grobs have a color, a size, a position, etc,
108 and all these properties are processed in the same way during
110 interpretation of the input file. To simplify these internal
111 operations these common actions and properties are grouped
112 together in an object called a @code{grob-interface}. There
113 are many other groupings of common properties like this, each
114 one given a name ending in @code{-interface}. In total there
115 are over 100 such interfaces. We shall see later why this is
116 of interest and use to the user.
118 These, then, are the main terms relating to objects which we
119 shall use in this chapter.
121 @node Naming conventions of objects and properties
122 @subsection Naming conventions of objects and properties
124 We met some object naming conventions previously, in
125 @ref{Contexts and engravers}. Here for reference is a list
126 of the most common object and property types together with
127 the conventions for naming them and a couple of examples of
128 some real names. We have used A to stand for any capitalised
129 alphabetic character and aaa to stand for any number of
130 lower-case alphabetic characters. Other characters are used
133 @multitable @columnfractions .33 .33 .33
134 @headitem Object/property type
135 @tab Naming convention
137 @item Contexts, Layout Objects
138 @tab Aaaa or AaaaAaaaAaaa
139 @tab Staff, GrandStaff,
141 @tab Aaaa_aaa_engraver
142 @tab Clef_engraver, Note_heads_engraver
144 @tab aaa-aaa-interface
145 @tab grob-interface, break-aligned-interface
146 @item Context Properties
147 @tab aaa or aaaAaaaAaaa
148 @tab alignAboveContext, skipBars
149 @item Layout Object Properties
150 @tab aaa or aaa-aaa-aaa
151 @tab direction, beam-thickness
154 As we shall see shortly, the properties of different types of
155 object are modified by different commands, so it is useful to
156 be able to recognise the type of object from the names of its
160 @node Tweaking methods
161 @subsection Tweaking methods
163 We have already met the commands @code{\set} and @code{\with},
164 used to change the properties of @strong{contexts} and to remove
165 and add @strong{engravers}, in
166 @ref{Modifying context properties} and @ref{Adding
167 and removing engravers}. We now must meet one more command.
169 The command to change the properties of @strong{layout objects} is
170 @code{\override}. Because this command has to modify
171 internal properties deep within LilyPond its syntax is not
172 as simple as the commands you have met so far. It needs to
173 know precisely which property of which object in which context
174 has to be modified, and what its new value is to be. Let's see
177 The general syntax of this command is:
180 \override @emph{context}.@emph{layout_object} #'@emph{layout_property} = #@emph{value}
184 This will set the property with the name @emph{layout_property}
185 of the layout object with the name
186 @emph{layout_object}, which is a member of the @emph{context}
187 context, to the value @emph{value}.
189 The @emph{context} can be omitted (and usually is) when the
190 required context is unambiguously implied and is one of lowest
191 level contexts, i.e., @code{Voice}, @code{ChordNames} or
192 @code{Lyrics}, and we shall omit it in many of the following
193 examples. We shall see later when it must be specified.
195 For now, don't worry about the @code{#'}, which must precede the
196 layout property, and the @code{#}, which must precede the value.
197 These must always be present in exactly this form. This is the
198 most common command used in tweaking, and most of the rest of
199 this chapter will be directed to presenting examples of how it is
202 Once overridden, the property retains its new value until it is
203 overridden again or a @code{\revert} command is encountered.
204 The @code{\revert} command has the following syntax and causes
205 the value of the property to revert to its original default
206 value; note, not its previous value if several @code{\override}
207 commands have been issued.
210 \revert @emph{context}.@emph{layout_object} #'@emph{layout_property}
213 Again, just like @emph{context} in the @code{\override} command,
214 @emph{context} is often not needed. It will be omitted
215 in many of the following examples.
217 There is another form of the override command,
218 @code{\overrideProperty}, which is occasionally required.
219 We mention it here for completeness, but for details see
220 @ruser{Difficult tweaks}.
221 @c Maybe explain in a later iteration -td
223 The final tweaking command which is available is @code{\tweak}.
224 It is not really a new command but a shorthand for an
225 @code{\override} command which must be used in a few special
226 circumstances. Again, we shall not discuss or use it here.
227 You may find the details in
228 @ruser{Objects connected to the input}.
229 @c Maybe explain in a later iteration -td
231 @node The Internals Reference manual
232 @section The Internals Reference manual
234 @cindex Internals Reference
237 * Properties of layout objects::
238 * Properties found in interfaces::
239 * Types of properties::
242 @node Properties of layout objects
243 @subsection Properties of layout objects
245 @cindex properties of layout objects
246 @cindex properties of grobs
247 @cindex grobs, properties of
248 @cindex layout objects, properties of
250 Suppose you have a slur in a score which, to your mind,
251 appears too thin and you'd like to draw it a little heavier.
252 How do you go about doing this? You know from the statements
253 earlier about the flexibility of LilyPond that such a thing
254 should be possible, and you would probably guess that an
255 @code{\override} command would be needed. But is there a
256 heaviness property for a slur, and if there is, how might it
257 be modified? This is where the Internals Reference manual
258 comes in. It contains all the information you might need to
259 construct this and all other @code{\override} commands.
261 Before we look at the Internals Reference a word of warning.
262 This is a @strong{reference} document, which means there is
263 little or no explanation contained within it: its purpose is
264 to present information precisely and concisely. This
265 means it might look daunting at first sight. Don't worry!
266 The guidance and explanation presented here will enable you
267 to extract the information from the Internals Reference for
268 yourself with just a little practice.
270 @cindex override example
271 @cindex Internals Reference, example of using
273 Let's use a concrete example with a simple fragment of real
276 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
281 g[( e]) e d[( f]) a |
285 The man who feels love's sweet e -- mo -- tion
290 Suppose now that we decide we would like the slurs to be a
291 little heavier. Is this possible? The slur is certainly a
292 layout object, so the question is, @q{Is there a property
293 belonging to a slur which controls the heaviness?} To answer
294 this we must look in the Internals Reference, or IR for short.
296 The IR for the version of LilyPond you are using may be found
297 on the LilyPond website at @uref{http://lilypond.org}. Go to the
298 documentation page and click on the Internals Reference link.
299 For learning purposes you should use the standard html version,
300 not the @q{one big page} or the PDF. For the next few
301 paragraphs to make sense you will need to actually do this
304 Under the heading @strong{Top} you will see five links. Select
305 the link to the @emph{Backend}, which is where information about
306 layout objects is to be found. There, under the heading
307 @strong{Backend}, select the link to @emph{All layout objects}.
308 The page that appears lists all the layout objects used in your
309 version of LilyPond, in alphabetic order. Select the link to
310 Slur, and the properties of Slurs are listed.
312 (An alternative way of finding this page is from the Notation
313 Reference. On one of the pages that deals with slurs you may
314 find a link to the Internals Reference. This link will
315 take you directly to this page, but often it is easier to go
316 straight to the IR and search there.)
318 This Slur page in the IR tells us first that Slur objects are
320 Slur_engraver. Then it lists the standard settings. Note
321 these are @strong{not} in alphabetic order. Browse down
322 them looking for a property that might control the heaviness
323 of slurs, and you should find
326 @code{thickness} (number)
328 Line thickness, generally measured in @code{line-thickness}
331 This looks a good bet to change the heaviness. It tells us that
332 the value of @code{thickness} is a simple @emph{number},
333 that the default value is 1.2, and that the units are
334 in another property called @code{line-thickness}.
336 As we said earlier, there are few to no explanations in the IR,
337 but we already have enough information to try changing the
338 slur thickness. We see that the name of the layout object
339 is @code{Slur}, that the name of the property to change is
340 @code{thickness} and that the new value should be a number
341 somewhat larger than 1.2 if we are to make slurs thicker.
343 We can now construct the @code{\override} command by simply
344 substituting the values we have found for the names, omitting
345 the context. Let's use a very large value for the thickness
346 at first, so we can be sure the command is working. We get:
349 \override Slur #'thickness = #5.0
352 Don't forget the @code{#'} preceding the
353 property name and and @code{#} preceding the new value!
355 The final question is, @q{Where should this command be
356 placed?} While you are unsure and learning, the best
357 answer is, @q{Within the music, before the first slur and
358 close to it.} Let's do that:
360 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
364 % Increase thickness of all following slurs from 1.2 to 5.0
365 \override Slur #'thickness = #5.0
367 g[( e]) e d[( f]) a |
371 The man who feels love's sweet e -- mo -- tion
377 and we see that the slur is indeed heavier.
379 So this is the basic way of constructing @code{\override}
380 commands. There are a few more complications that we
381 shall meet in later sections, but you now know all the
382 essentials required to make up your own -- but you will
383 still need some practice. This is provided in the examples
386 @subheading Finding the context
387 @cindex context, finding
389 But first, what if we had needed to specify the Context?
390 What should it be? We could guess that slurs are in
391 the Voice context, as they are clearly closely associated
392 with individual lines of music, but can we be sure? To
393 find out, go back to the top of the IR page describing the
394 Slur, where it says @q{Slur objects are created by: Slur
395 engraver}. So slurs will be created in whichever context
396 the @code{Slur_engraver} is in. Follow the link to the
397 @code{Slur_engraver} page. At the very bottom it tells
398 us that @code{Slur_engraver} is part of five Voice contexts,
399 including the standard voice context, @code{Voice}, so our
400 guess was correct. And because @code{Voice} is one of the
401 lowest level contexts which is implied unambiguously by
402 the fact that we are entering notes, we can omit it in this
405 @subheading Overriding once only
407 @cindex overriding once only
408 @cindex once override
411 As you can see, @emph{all} the slurs are thicker in the
412 final example above. But what if we
413 wanted just the first slur to be thicker? This is achieved
414 with the @code{\once} command. Placed immediately before
415 the @code{\override} command it causes it to change only the
416 slur which begins on the @strong{immediately following} note.
418 immediately following note does not begin a slur the command
419 has no effect at all -- it is not remembered until a slur
420 is encountered, it is simply discarded. So the command with
422 repositioned as follows:
424 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
429 % Increase thickness of immediately following slur only
430 \once \override Slur #'thickness = #5.0
432 g[( e]) e d[( f]) a |
436 The man who feels love's sweet e -- mo -- tion
442 Now only the first slur is made heavier.
444 The @code{\once} command can also be used before @code{\set}
445 and @code{\unset}, and before the command to be introduced
446 in the following section -- @code{revert}.
448 @subheading Reverting
451 @cindex default properties, reverting
454 Finally, what if we wanted just the first two slurs to be
455 heavier? Well, we could use two commands, each preceded by
456 @code{\once} placed immediately before each of the notes where
459 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
464 % Increase thickness of immediately following slur only
465 \once \override Slur #'thickness = #5.0
467 % Increase thickness of immediately following slur only
468 \once \override Slur #'thickness = #5.0
469 g[( e]) e d[( f]) a |
473 The man who feels love's sweet e -- mo -- tion
479 or we could omit the @code{\once} command and use the
480 @code{\revert} command
481 to return the @code{thickness} property to its default value
482 after the second slur:
484 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
489 % Increase thickness of all following slurs from 1.2 to 5.0
490 \override Slur #'thickness = #5.0
493 % Revert thickness of all following slurs to default of 1.2
494 \revert Slur #'thickness
499 The man who feels love's sweet e -- mo -- tion
505 The @code{\revert} command can be used to return any property
506 changed with @code{\override} back to its default value.
507 You may use whichever method best suits what you want to do.
509 That concludes our introduction to the IR, and the basic
510 method of tweaking. Several examples follow in the later
511 sections of this Chapter, partly to introduce you to some of the
512 additional features of the IR, and partly to give you more
513 practice in extracting information from it. These examples will
514 contain progressively fewer words of guidance and explanation.
516 @node Properties found in interfaces
517 @subsection Properties found in interfaces
519 @cindex interface properties
520 @cindex properties in interfaces
522 Suppose now that we wish to print the lyrics in italics. What
523 form of @code{\override} command do we need to do this?
524 We first look in the IR page listing @q{All layout objects}, as
525 before, and look for an object that might control lyrics. We
526 find @code{LyricText}, which looks right. Clicking on this shows
527 the settable properties for lyric text. These include the
528 @code{font-series} and @code{font-size}, but nothing that might
529 give an italic shape.
530 This is because the shape property is one that is common to all
531 font objects, so, rather than including it in every layout
532 object, it is grouped together with other similar common
533 properties and placed in an @strong{Interface}, the
534 @code{font-interface}.
536 So now we need to learn how to find the properties of interfaces,
537 and to discover what objects use these interface properties.
539 Look again at the IR page which describes LyricText. At the
540 bottom of the page is a list of clickable (in the html versions
541 of the IR) interfaces which LyricText supports. The list has
542 seven items, including @code{font-interface}.
543 Clicking on this brings up the properties associated
544 with this interface, which are also properties of all the objects
545 which support it, including LyricText.
547 Now we see all the user-settable properties which control fonts,
548 including @code{font-shape(symbol)}, where @code{symbol} can be
549 set to @code{upright}, @code{italics} or @code{caps}.
551 You will notice that that @code{font-series} and @code{font-size}
552 are also listed there.
553 This immediately raises the question: Why are the common font
554 properties @code{font-series} and @code{font-size} listed under
555 @code{LyricText} as well as under the interface
556 @code{font-interface} but @code{font-shape} is not? The answer
557 is that @code{font-series} and @code{font-size} are changed
558 from their global default values when a @code{LyricText} object
559 is created, but @code{font-shape} is not. The entries in
560 @code{LyricText} then tell you the values for those two
561 properties which apply to @code{LyricText}. Other objects
562 which support @code{font-interface} will set these
563 properties diferently when they are created.
565 Let's see if we can now construct the @code{\override} command
566 to change the lyrics to italics. The object is @code{LyricText},
567 the property is @code{font-shape} and the value is
568 @code{italic}. As before, we'll omit the context.
570 As an aside, although it is an important one, note that because
572 @code{font-shape} are symbols they must be introduced with a
573 single apostrophe, @code{'}. That is why apostrophes
574 are needed before @code{thickness} in the earlier example
575 and @code{font-shape}. These are both symbols too.
576 Symbols are special names which are known internally to
577 LilyPond. Some of them are the names of properties,
578 like @code{thickness} or @code{font-shape}, others are in
579 effect special values that can be given to properties, like
580 @code{italic}. Note the distinction from arbitary
581 text strings, which would appear as @code{"a text string"}.
583 Ok, so the @code{\override} command we need to print the lyrics
587 \override LyricText #'font-shape = #'italic
591 and this should be placed just in front of and close to the
592 lyrics which it should affect, like this:
594 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
599 g[( e]) e d[( f]) a |
603 \override LyricText #'font-shape = #'italic
604 The man who feels love's sweet e -- mo -- tion
610 and the lyrics are all printed in italics.
612 @subheading Specifying context in lyric mode
613 @cindex context, specifying in lyric mode
615 In the case of lyrics, if you try specifying the context in the
616 format given earlier the command will fail. A syllable
617 entered in lyricmode is terminated by either a space,
618 a newline or a digit. All other characters are included
619 as part of the syllable. For this reason a space or newline
620 must appear before the terminating @code{@}} to prevent it being
621 included as part of the final syllable. Similarly,
622 spaces must be inserted before and after the
623 period or dot, @q{.}, separating the context name from the
624 object name, as otherwise the two names are run together and
625 the interpreter cannot recognise them. So the command should be:
628 \override Lyrics . LyricText #'font-shape = #'italic
631 @warning{In lyrics always leave whitespace between the final
632 syllable and the terminating brace.}
634 @warning{In overrides in lyrics always place spaces around
635 the dot between the context name and the object name.}
637 @node Types of properties
638 @subsection Types of properties
640 @cindex Property types
642 So far we have seen two types of property: @code{number} and
643 @code{symbol}. To be valid, the value given to a property
644 must be of the correct type and obey the rules for that type.
645 The type of property is always shown in brackets after the
646 property name in the IR. Here is a list of the types you may
647 need, together with the rules for that type, and some examples.
648 You must always add a hash symbol, @code{#}, of course,
649 to the front of these values when they are entered in the
650 @code{\override} command.
652 @multitable @columnfractions .2 .45 .35
653 @headitem Property type
657 @tab Either True or False, represented by #t or #f
658 @tab @code{#t}, @code{#f}
659 @item Dimension (in staff space)
660 @tab A positive decimal number (in units of staff space)
661 @tab @code{2.5}, @code{0.34}
663 @tab A valid direction constant or its numerical equivalent
664 @tab @code{#LEFT}, @code{#CENTER}, @code{#UP},
667 @tab A positive whole number
668 @tab @code{3}, @code{1}
670 @tab A bracketed set of items separated by spaces,
671 preceded by an apostrophe
672 @tab @code{'(left-edge staff-bar)}, @code{'(1)},
673 @code{'(1.0 0.25 0.5)}
675 @tab Any valid markup
676 @tab @code{\markup @{ \italic "cresc." @}}
678 @tab A fraction of a whole note constructed with the
680 @tab @code{(ly:make-moment 1 4)},
681 @code{(ly:make-moment 3 8)}
683 @tab Any positive or negative decimal value
684 @tab @code{3.5}, @code{-2.45}
685 @item Pair (of numbers)
686 @tab Two numbers separated by a @q{space . space} and enclosed
687 in brackets preceded by an apostrophe
688 @tab @code{'(2 . 3.5)}, @code{'(0.1 . -3.2)}
690 @tab Any of the set of permitted symbols for that property,
691 preceded by an apostrophe
692 @tab @code{'italic}, @code{'inside}
694 @tab A procedure or @code{#f} (to cause no action)
695 @tab @code{bend::print}, @code{ly:text-interface::print},
698 @tab A list of three items enclosed in brackets and preceded
699 by a hash sign, @code{#}.
700 @tab @code{#(#t #t #f)}
703 @node Appearance of objects
704 @section Appearance of objects
706 Let us now put what we have learnt into practice with a few
707 examples which show how tweaks may be used to change the
708 appearance of the printed music.
711 * Visibility and color of objects::
715 @node Visibility and color of objects
716 @subsection Visibility and color of objects
718 In the educational use of music we might wish to print a score
719 with certain elements omitted as an exercise for the student,
720 who is required to supply them. As a simple example,
721 let us suppose the exercise is to supply the missing barlines
722 in a piece of music. But the barlines are normally inserted
723 automatically. How do we prevent them printing?
725 As before, we go to the IR to find the layout object which prints
726 barlines. Going via @emph{Backend} and @emph{All layout objects}
728 is a layout object called @code{BarLine}. Its properties include
729 two that control its visibility: @code{break-visibility} and
730 @code{stencil}. Barline also supports a number of interfaces,
731 including the @code{grob-interface}, where we find the
732 @code{transparent} and the @code{color} properties. All
733 of these can affect the visibility of barlines (and, of course,
734 by extension, many other layout objects too.) Let's consider
735 each of these in turn.
738 @cindex stencil property
740 This property controls the appearance of the barlines by specifying
741 the symbol (glyph) which should be printed. In common
742 with many other properties, it can be set to print nothing by
743 setting its value to @code{#f}. Let's try it, as before, omitting
744 the implied Context, @code{Voice}:
746 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
749 \override BarLine #'stencil = ##f
756 The barlines are still printed. What is wrong? Go back to the
757 IR and look again at the page giving the properties of BarLine.
758 At the top of the page it says @qq{Barline objects are created
759 by: Bar_engraver}. Go to the @code{Bar_engraver} page.
761 it gives a list of Contexts in which the bar engraver operates.
762 All of them are of the type @code{Staff}, so the reason the
763 @code{\override} command failed to work as expected is because
764 @code{Barline} is not in the default @code{Voice} context.
766 is specified wrongly, the command simply does not work. No
767 error message is produced, and nothing is logged in the log
768 file. Let's try correcting it by adding the correct context:
770 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
773 \override Staff.BarLine #'stencil = ##f
780 Now the barlines have vanished.
782 @subheading break-visibility
784 @cindex break-visibility property
786 We see from the @code{BarLine} properties in the IR that the
787 @code{break-visibility} property requires a vector of three
789 These control respectively whether barlines are printed at
790 the end of a line, in the middle of lines, and at the beginning
791 of lines. For our example we want all barlines to be suppressed,
792 so the value we need is @code{#(#f #f #f)}.
793 Let's try that, remembering
794 to include the @code{Staff} context. Note also that in writing
795 this value we have two hash signs before the opening bracket.
796 One is required as part of the value to introduce a vector,
797 and one is required, as always, to precede the value itself in
798 the @code{\override} command.
800 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
803 \override Staff.BarLine #'break-visibility = ##(#f #f #f)
810 And we see this too removes all the barlines.
812 @subheading transparent
813 @cindex transparent property
815 We see from the properties specified in the @code{grob-interface}
816 page in the IR that the @code{transparent} property is a boolean.
818 should be set to @code{#t} to make the grob transparent.
819 In this next example let us make the time signature invisible
820 rather than the barlines.
821 To do this we need to find the grob name for the time signature.
823 the @q{All layout objects} page in the IR to find the properties
824 of the @code{TimeSignature} layout object. This is produced by
825 the @code{Time_signature_engraver} which you can check also lives
826 in the @code{Staff} context and also supports the
827 @code{grob-interface}. So the command to make the time signature
830 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
833 \override Staff.TimeSignature #'transparent = ##t
841 The time signature is gone, but this command leaves a gap where
842 the time signature should be. Maybe this is what is wanted for
843 an exercise for the student to fill it in, but in other
844 circumstances a gap might be undesirable. To remove it, the
845 stencil for the time signature should be set to @code{#f}
848 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
851 \override Staff.TimeSignature #'stencil = ##f
859 and the difference is obvious: setting the stencil to @code{#f}
860 removes the object entirely; making the object @code{transparent}
861 leaves it where it is, but makes it invisible.
864 @cindex color property
866 Finally we could make the barlines invisible by coloring
867 them white. The @code{grob-interface} specifies that the
868 color property value is a list, but there is no
869 explanation of what that list should be. The list it
870 requires is actually a list of values in internal units,
871 but, to avoid having to know what these are, several ways
872 are provided to specify colors. The first way is to use one
873 of the @q{normal} colours listed in the first table in
874 @ruser{List of colors}. To set the barlines to white
877 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
880 \override Staff.BarLine #'color = #white
888 and again, we see the barlines are not visible. Note that
889 @emph{white} is not preceded by an apostrophe -- it is not
890 a symbol, but a @emph{function}. When called, it provides
891 the list of internal values required to set the color to
892 white. The other colors in the normal list are functions
893 too. To convince yourself this is working you might like
894 to change the color to one of the other functions in the
900 The second way of changing the color is to use the list of
901 X11 color names in the second list in @ruser{List of colors}.
902 However, these must be preceded by another function, which
903 converts X11 color names into the list of internal values,
904 @code{x11-color}, like this:
906 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
909 \override Staff.BarLine #'color = #(x11-color 'white)
917 Note that in this case the function @code{x11-color} takes
918 a symbol as an argument, so the symbol must be preceded by
919 an apostrophe and the two enclosed in brackets.
924 There is yet a third function, one which converts RGB values into
925 internal colors -- the @code{rgb-color} function. This takes
926 three arguments giving the intensities of the red, green and
927 blue colors. These take values in the range 0 to 1. So to
928 set the color to red the value should be @code{(rgb-color 1 0 0)}
929 and to white it should be @code{(rgb-color 1 1 1)}:
931 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
934 \override Staff.BarLine #'color = #(rgb-color 1 1 1)
941 Finally, there is also a grey scale available as part of the
942 X11 set of colors. These range from black, @code{'grey0'},
943 to white, @code{'grey100}, in steps of 1. Let's illustrate
944 this by setting all the layout objects in our example to
945 various shades of grey:
947 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
950 \override Staff.StaffSymbol #'color = #(x11-color 'grey30)
951 \override Staff.TimeSignature #'color = #(x11-color 'grey60)
952 \override Staff.Clef #'color = #(x11-color 'grey60)
953 \override Voice.NoteHead #'color = #(x11-color 'grey85)
954 \override Voice.Stem #'color = #(x11-color 'grey85)
955 \override Staff.BarLine #'color = #(x11-color 'grey10)
963 Note the contexts associated with each of the layout objects.
964 It is important to get these right, or the commands will not
965 work! Remember, the context is the one in which the appropriate
966 engraver is placed. The default context for engravers can be
967 found by starting from the layout object, going from there to
968 the engraver which produces it, and on the engraver page in the
969 IR it tells you in which context the engraver will normally be
973 @node Size of objects
974 @subsection Size of objects
976 Let us begin by looking again at the earlier example
977 see @ref{Nesting music expressions}) which showed
978 how to introduce a new temporary staff, as in an @rglos{ossia}.
980 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
988 alignAboveContext = "main" }
996 Ossia are normally written without clef and time signature, and
997 are usually printed slightly smaller than the main staff. We
998 already know now how to remove the clef and time signature --
999 we simply set the stencil of each to @code{#f}, as follows:
1001 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1002 \new Staff ="main" {
1009 alignAboveContext = "main"
1012 \override Staff.Clef #'stencil = ##f
1013 \override Staff.TimeSignature #'stencil = ##f
1023 where the extra pair of braces after the @code{\with} clause are
1024 required to ensure the enclosed overrrides and music are applied
1027 But what is the difference between modifying the staff context by
1028 using @code{\with} and modifying the stencils of the clef and the
1029 time signature with \override? The main difference is that
1030 changes made in a @code{\with} clause are made at the time the
1031 context is created, and remain in force as the @strong{default}
1032 values for the duration of that context, whereas
1033 @code{\set} or @code{\override} commands embedded in the
1034 music are dynamic -- they make changes synchronised with
1035 a particular point in the music. If changes are unset or
1036 reverted using @code{\unset} or @code{\revert} they return to
1037 their default values, which will be the ones set in the
1038 @code{\with} clause, or if none have been set there, the normal
1041 Some context properties
1042 can be modified only in @code{\with} clauses. These are those
1043 properties which cannot sensibly be changed after the context
1044 has been created. @code{alignAboveContext} and its partner,
1045 @code{alignBelowContext}, are two such properties -- once the
1046 staff has been created its alignment is decided and it would
1047 make no sense to try to change it later.
1049 The default values of layout object properties can also be set
1050 in @code{\with} clauses. Simply use the normal @code{\override}
1051 command leaving out the context name, since this is unambiguously
1052 defined as the context which the @code{\with} clause is modifying.
1053 If fact, an error will be generated if a context is specified
1056 So we could replace the example above with
1058 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1059 \new Staff ="main" {
1066 alignAboveContext = "main"
1067 % Don't print clefs in this staff
1068 \override Clef #'stencil = ##f
1069 % Don't print time signatures in this staff
1070 \override TimeSignature #'stencil = ##f
1079 Finally we come to changing the size of layout objects.
1081 Some layout objects are created as glyphs selected from
1082 a typeface font. These include noteheads, accidentals, markup,
1083 clefs, time signatures, dynamics and lyrics.
1084 Their size is changed by modifying the
1085 @code{font-size} property, as we shall shortly see. Other
1086 layout objects such as slurs and ties -- in general, spanner
1087 objects -- are drawn individually, so there is no
1089 associated with them. These objects generally derive their
1090 size from the objects to which they are attached, so usually
1091 there is no need to change their size manually. Still other
1092 properties such as the length of stems and barlines, thickness
1093 of beams and other lines, and the separation of staff lines all
1094 need to be modified in special ways.
1096 Returning to the ossia example, let us first change the font-size.
1097 We can do this in two ways. We can either change the size of the
1098 fonts of each object type, like @code{NoteHead}s with commands
1102 \override NoteHead #'font-size = #-2
1105 or we can change the size of all fonts by setting a special
1106 property, @code{fontSize}, using @code{\set}, or by including
1107 it in a @code{\with} clause (but without the @code{\set}).
1113 Both of these statements would cause the font size to be reduced
1114 by 2 steps from its previous value, where each
1115 step reduces or increases the size by approximately 12%.
1117 Let's try it in our ossia example:
1119 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1120 \new Staff ="main" {
1127 alignAboveContext = "main"
1128 \override Clef #'stencil = ##f
1129 \override TimeSignature #'stencil = ##f
1130 % Reduce all font sizes by ~24%
1140 This is still not quite right. The noteheads and flags are
1141 smaller, but the stems are too long in proportion and the
1142 staff lines are spaced too widely apart. These need to be
1143 scaled down in proportion to the font reduction.
1146 @cindex size, changing
1147 @cindex stem length, changing
1148 @cindex staff line spacing, changing
1150 This can be done with the help of a special function called
1151 @code{magstep} provided for exactly this purpose. It takes
1152 one argument, the change in font size (#-2 in the example above)
1153 and returns a scaling factor suitable for reducing other
1154 objects in proportion. It is used like this:
1156 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1157 \new Staff ="main" {
1164 alignAboveContext = "main"
1165 \override Clef #'stencil = ##f
1166 \override TimeSignature #'stencil = ##f
1168 % Reduce stems and line spacing to match
1169 \override StaffSymbol #'staff-space = #(magstep -2)
1179 Since the length of stems and many other length-related properties
1180 are always calculated relative to the
1181 value of the @code{staff-space} property these are automatically
1182 scaled down in length too. Note that this affects only the
1183 vertical scale of the ossia -- the horizontal scale is determined
1184 by the layout of the main music in order to remain synchronised
1185 with it, so it is not affected by any of these changes in size.
1186 Of course, if the scale of all the main music were changed in this
1187 way then the horizontal spacing would be affected. This is
1188 discussed later in the layout section.
1190 This, then, completes the creation of an ossia. The sizes of all
1191 other objects may be modified in analogous ways.
1193 @node Placement of objects
1194 @section Placement of objects
1197 * Automatic behaviour::
1198 * Within-staff objects::
1199 * Outside staff objects::
1203 @node Automatic behaviour
1204 @subsection Automatic behaviour
1206 There are some objects in musical notation that belong to
1207 the staff and there are other objects that should be
1208 placed outside the staff. These are called within-staff
1209 objects and outside-staff objects respectively.
1211 Within-staff objects are those that are located on the staff
1212 -- note heads, stems, accidentals, etc. The positions of
1213 these are usually fixed by the music itself -- they are
1214 vertically positioned on specific lines of the staff or are
1215 tied to other objects that are so positioned. Collisions of
1216 noteheads, stems and accidentals in closely set chords are
1217 normally avoided automatically. There are commands and
1218 overrides which can modify this automatic behaviour, as we
1221 Objects belonging outside the staff include things such as
1222 rehearsal marks, text and dynamic markings. LilyPond's rule for
1223 the vertical placement of outside-staff objects is to place them
1224 as close to the staff as possible but not so close that they
1225 collide with any other object. LilyPond uses the
1226 @code{outside-staff-priority} property to determine the order in
1227 which the objects should be placed, as follows.
1229 First, LilyPond places all the within-staff objects.
1230 Then it sorts the outside-staff objects according to their
1231 @code{outside-staff-priority}. The outside-staff objects are
1232 taken one by one, beginning with the object with the lowest
1233 @code{outside-staff-priority}, and placed so that they do not
1234 collide with any objects that have already been placed. That is,
1235 if two outside-staff grobs are competing for the same space, the
1236 one with the lower @code{outside-staff-priority} will be placed
1237 closer to the staff. If two objects have the same
1238 @code{outside-staff-priority} the one encountered first will be
1239 placed closer to the staff.
1241 In the following example all the markup texts have the same
1242 priority (since it is not explicity set). Note that @q{Text3}
1243 is automatically positioned close to the staff again, nestling
1246 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1253 Staves are also positioned, by default, as closely together as
1254 possible (subject to a minimum separation). If notes project
1255 a long way towards an adjacent staff they will force the
1256 staves further apart only if an overlap of the notation
1257 would otherwise occur. The following example demonstrates
1258 this @q{nestling} of the notes on adjacent staves:
1260 @lilypond[quote,ragged-right,verbatim]
1263 \relative c' { c a, }
1266 \relative c'''' { c a, }
1271 @c TODO Mention somewhere, probably not here, how to avoid staves
1272 @c interleaving too much by specifying skyline-horizontal-padding
1273 @c Presumably this moves the skyline boundary further out, making
1274 @c objects appear wider? Not yet tested. -td
1276 @node Within-staff objects
1277 @subsection Within-staff objects
1279 We have already seen how the commands @code{\voiceXXX} affect
1280 the direction of slurs, ties, fingering and
1281 everything else which depends on the direction of the stems.
1282 These commands are essential when writing polyphonic music to
1283 permit interweaving melodic lines to be distinguished.
1284 But occasionally it may be necessary to override this automatic
1285 behaviour. This can be done for whole sections of music or even
1286 for an individual note. The property which controls this
1287 behaviour is the @code{direction} property of each layout object.
1288 We first explain what this does, and then introduce a number of
1289 ready-made commands which avoid your having to code explicit
1290 overrides for the more common modifications.
1292 Some layout objects like slurs and ties curve, bend or point
1293 either up or down; others like stems and flags also move to
1294 right or left when they point up or down. This is controlled
1295 automatically when @code{direction} is set.
1297 The following example shows in bar 1 the default behaviour of
1299 with those on high notes pointing down and those on low notes
1300 pointing up, followed by four notes with all stems forced down,
1301 four notes with all stems forced up, and finally four notes
1302 reverted back to the default behaviour.
1304 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1306 \override Stem #'direction = #DOWN
1308 \override Stem #'direction = #UP
1310 \revert Stem #'direction
1314 Here we use the constants @code{DOWN} and @code{UP}.
1315 These have the values @code{-1} and @code{+1} respectively, and
1316 these numerical values may be used instead. The value @code{0}
1317 may also be used in some cases. It is simply treated as meaning
1318 @code{UP} for stems, but for some objects it means @q{center}.
1319 There is a constant, @code{CENTER} which has the value @code{0}.
1321 However, these explicit overrides are not usually used, as there
1322 are simpler equivalent predefined commands available.
1323 Here is a table of the commonest. The meaning of each is stated
1324 where it is not obvious.
1326 @c TODO put @code{} round all these
1328 @multitable @columnfractions .2 .2 .2 .4
1335 @tab \arpeggioNeutral
1336 @tab Arrow is at bottom, at top, or no arrow
1340 @tab Direction of movement to avoid staff lines
1343 @tab \dynamicNeutral
1345 @item \phrasingSlurDown
1346 @tab \phrasingSlurUp
1347 @tab \phrasingSlurNeutral
1348 @tab Note: distinct from slur commands
1357 @item \textSpannerDown
1359 @tab \textSpannerNeutral
1360 @tab Text entered as spanner is below/above staff
1368 @tab Tuplets are below/above notes
1371 Note that these predefined commands may @strong{not} be
1372 preceded by @code{\once}. If you wish to limit the
1373 effect to a single note you must either use the equivalent
1374 @code{\once \override} command or use the predefined command
1375 followed after the affected note by the corresponding
1376 @code{\xxxNeutral} command.
1378 @subheading Fingering
1379 @cindex fingering, placement
1381 The placement of fingering is also affected by the value
1382 of its @code{direction} property, but there are special
1383 commands which allow the fingering of individual notes
1384 of chords to be controlled, with the fingering being placed
1385 above, below, to the left or to the right of each note.
1387 First, here's the effect of @code{direction} on fingering,
1388 the first bar shows the default, then the effect of specifying
1389 @code{DOWN} and @code{UP}:
1391 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1393 \override Fingering #'direction = #DOWN
1395 \override Fingering #'direction = #UP
1399 This is how to control fingering on single notes, but the
1401 property is ignored for chords. Instead, by default, the
1402 fingering is automatically placed both above and below the
1403 notes of a chord, as shown:
1405 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1411 Greater control over the placement of fingering of the
1412 individual notes in a chord is possible by using
1413 the @code{\set fingeringOrientations} command. The format of
1417 @code{\set fingeringOrientations = #'([up] [left/right] [down])}
1421 @code{\set} is used because @code{fingeringOrientations} is a
1422 property of the @code{Voice} context, created and used by the
1423 @code{New_fingering_engraver}.
1425 The property may be set to a list of one to three values.
1426 It controls whether fingerings may be placed above (if
1427 @code{up} appears in the list), below (if @code{down} appears),
1428 to the left (if @code{left} appears, or to the right
1429 (if @code{right} appears). Conversely, if a location is not
1430 listed, no fingering is placed there. LilyPond takes these
1431 contraints and works out the best placement for the fingering
1432 of the notes of the following chords. Note that @code{left} and
1433 @code{right} are mutually exclusive -- fingering may be placed
1434 only on one side or the other, not both.
1436 To control the placement of the fingering of a single note
1437 using this command it is necessary to write it as a single
1438 note chord by placing angle brackets round it.
1440 Here are a few examples:
1442 @lilypond[quote,fragment,ragged-right,verbatim,relative=1]
1443 \set fingeringOrientations = #'(left)
1445 < c-1 e-2 g-3 b-5 > 4
1446 \set fingeringOrientations = #'(left)
1448 < c-1 e-2 g-3 b-5 > 4
1449 \set fingeringOrientations = #'(up left down)
1451 < c-1 e-2 g-3 b-5 > 4
1452 \set fingeringOrientations = #'(up left)
1454 < c-1 e-2 g-3 b-5 > 4
1455 \set fingeringOrientations = #'(right)
1457 < c-1 e-2 g-3 b-5 > 4
1461 If the fingering seems a little crowded the @code{font-size}
1462 could be reduced. The default value can be seen from the
1463 @code{Fingering} object in the IR to be @code{-5}, so let's
1466 @lilypond[quote,fragment,ragged-right,verbatim,relative=1]
1467 \override Fingering #'font-size = #-7
1468 \set fingeringOrientations = #'(left)
1470 < c-1 e-2 g-3 b-5 > 4
1471 \set fingeringOrientations = #'(left)
1473 < c-1 e-2 g-3 b-5 > 4
1474 \set fingeringOrientations = #'(up left down)
1476 < c-1 e-2 g-3 b-5 > 4
1477 \set fingeringOrientations = #'(up left)
1479 < c-1 e-2 g-3 b-5 > 4
1480 \set fingeringOrientations = #'(right)
1482 < c-1 e-2 g-3 b-5 > 4
1485 @node Outside staff objects
1486 @subsection Outside staff objects
1488 Outside-staff objects are automatically placed to avoid collisions.
1489 Objects with the lower value of @code{outside-staff-priority}
1490 property are placed nearer to the staff, and other outside-staff
1491 objects are then raised as far as necessary to avoid collisions.
1492 The @code{outside-staff-priority} is defined in the
1493 @code{grob-interface} and so is a property of all layout objects.
1494 It is set to @code{#f} (the default) for all within-staff objects,
1495 and is set explicitly to the default numerical value appropriate
1496 to the each object as it is created. The following table shows
1497 the default numerical values for some of the commonest
1498 outside-staff objects. Others may be found in the object
1499 properties listed in the IR.
1501 @multitable @columnfractions .3 .3
1502 @headitem Layout Object @tab Priority
1503 @item @code{BarNumber} @tab @code{ 100}
1504 @item @code{DynamicLineSpanner} @tab @code{ 250}
1505 @item @code{DynamicText} @tab @code{ 250}
1506 @item @code{MetronomeMark} @tab @code{1000}
1507 @item @code{OttavaBracket} @tab @code{ 400}
1508 @item @code{RehearsalMark} @tab @code{1500}
1509 @item @code{TextScript} @tab @code{ 450}
1512 TODO Add example showing iteraction of all these
1514 If this ordering does not give you the placing you want, the
1515 priority of the objects may be overridden. Suppose we would
1516 like @qq{Text3} to be placed above @qq{Text4} in the example
1517 under Automatic behaviour, above (see @ref{Automatic behaviour}).
1518 All we need to do is to look up the priority of @code{TextScript}
1519 in the IR or in the table above, and increase the priority of
1520 @qq{Text3} to a higher value:
1522 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1525 \once \override TextScript #'outside-staff-priority = #500
1530 This certainly lifts @qq{Text3} above @qq{Text4} but it also
1531 lifts it above @qq{Text2}, and @qq{Text4} now drops down.
1532 Perhaps this is not so good. Can we instead position them all
1533 at the same distance from the staff? To do this, we clearly
1534 will need to space the notes out horizontally to make more
1535 room for the text. This is done using the @code{fatText}
1538 @subheading \fatText
1541 @cindex notes, spreading out with text
1543 By default, text produced by markup takes up no horizontal space
1544 as far as laying out the music is concerned. The @code{\fatText}
1545 command reverses this behaviour, causing the notes to be spaced
1546 out as far as is necessary to accommodate the text:
1548 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1549 \fatText % Cause notes to space out to accommodate text
1556 The command to revert to the default behaviour is
1557 @code{\emptyText}. Remember @code{\once} only works with
1558 @code{\override}, @code{\set}, @code{\revert} or @code{unset},
1559 so cannot be used with @code{\fatText}.
1561 Markup text will also avoid notes which project above the staff.
1562 If this is not desired, the automatic displacement upwards may
1563 be turned off by setting the priority to @code{#f}. Here's an
1564 example to show how markup text interacts with such notes.
1566 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1567 % This markup is short enough to fit without collision
1571 % This is too long to fit, so it is displaced upwards
1575 % Turn off collision avoidance
1576 \once \override TextScript #'outside-staff-priority = ##f
1580 % Turn off collision avoidance
1581 \once \override TextScript #'outside-staff-priority = ##f
1582 \fatText % and turn on fatText
1583 c,,2^"Long Text " % Spaces at end are honoured
1588 @subheading Dynamics
1590 Dynamic markings will normally be positioned beneath the
1591 staff, but may be positioned above with the @code{dynamicUp}
1592 command. They will be positioned vertically relative to the
1593 note to which they are attached, and will float below (or above)
1594 all within-staff objects such as phrasing slurs and bar numbers.
1595 This can give quite acceptable results, as this example
1598 @lilypond[quote,fragment,ragged-right,verbatim,relative=1]
1603 bes4.~\f\< \( bes4 bes8 des4\ff\> c16 bes\! |
1604 ees,2.~\)\mf ees4 r8 |
1607 However, if the notes and attached dynamics are close
1608 together the automatic placement will avoid collisions
1609 by displacing later dynamic markings further away, but this may
1610 not be the optimum placement, as this rather artificial example
1613 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1619 Should a similar situation arise in @q{real} music, it may
1620 be preferable to space out the notes
1621 a little further, so the dynamic markings can all fit at the
1622 same vertical distance from the staff. We were able to do this
1623 for markup text by using the @code{\fatText} command, but there
1624 is no equivalent command for dynamic marks. So we shall have to
1625 work out how to do this using @code{\override} commands.
1627 @subheading Grob sizing
1630 @cindex sizing grobs
1631 @cindex @code{X-offset}
1632 @cindex @code{Y-offset}
1633 @cindex @code{X-extent}
1634 @cindex @code{Y-extent}
1636 First we must learn how grobs are sized. All grobs have a
1637 reference point defined within them which is used to position
1638 them relative to their parent object. This point in the grob
1639 is then positioned at a horizontal distance, @code{X-offset},
1640 and at a vertical distance, @code{Y-offset}, from its parent.
1641 The horizontal extent of the object is given by a pair of
1642 numbers, @code{X-extent}, which say where the left and right
1643 edges are relative to the reference point. The vertical extent
1644 is similarly defined by a pair of numbers, @code{Y-extent}.
1645 These are properties of all grobs which support the
1646 @code{grob-interface}.
1648 @cindex @code{extra-spacing-width}
1650 By default, outside-staff objects are given a width of zero so
1651 that they may overlap in the horizontal direction. This is done
1652 by by the trick of adding infinity to the leftmost extent and
1653 minus infinity to the rightmost extent by setting the
1654 @code{extra-spacing-width} to @code{'(+inf.0 . -inf.0)}. So
1655 to ensure they do not overlap in the horizontal direction we
1656 must override this value of @code{extra-spacing-width} to
1657 @code{'(0 . 0)} so the true width shines through. This is
1658 the command to do this for dynamic text:
1661 \override DynamicText #'extra-spacing-width = #'(0 . 0)
1665 Let's see if this works in our previous example:
1667 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1669 \override DynamicText #'extra-spacing-width = #'(0 . 0)
1674 Well, it has certainly stopped the dynamic marks being
1675 displaced, but two problems remain. The marks should be
1676 spaced a little further apart and it would be better
1677 if they were all the same distance from the staff.
1678 We can solve the first problem easily. Instead of making
1679 the @code{extra-spacing-width} zero we could add a little
1680 more to it. The units are the space between two staff
1681 lines, so moving the left edge half a unit to the left and the
1682 right edge half a unit to the right should do it:
1684 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1686 % Extend width by 1 staff space
1687 \override DynamicText #'extra-spacing-width = #'(-0.5 . 0.5)
1692 This looks better, but maybe we would prefer the dynamic marks
1693 to be aligned along the same baseline rather than going up and
1694 down with the notes. The property to do this is
1695 @code{staff-padding} which is covered in the following section.
1698 @node Collisions of objects
1699 @section Collisions of objects
1703 * Fixing overlapping notation::
1706 @node Moving objects
1707 @subsection Moving objects
1709 This may come as a surprise, but LilyPond is not perfect. Some
1710 notation elements can overlap. This is unfortunate, but in fact
1711 rather rare. Usually the need to move objects is for clarity or
1712 aesthetic reasons -- they would look better with a little more
1713 or a little less space around them.
1715 There are three main main approaches to resolving overlapping
1716 notation. They should be considered in the following order:
1720 The @strong{direction} of one of the overlapping objects may
1721 be changed using the predefined commands listed above for
1722 within-staff objects (see @ref{Within-staff objects}).
1723 Stems, slurs, beams, ties, dynamics, text and tuplets may be
1724 repositioned easily in this way. The limitation is that you
1725 have a choice of only two positions, and neither may be
1728 The @strong{object properties}, which LilyPond uses
1729 when positioning layout objects, may be modified using
1730 @code{\override}. The advantages
1731 of making changes to this type of property are (a) that some
1732 other objects will be moved automatically if necessary to make
1733 room and (b) the single override can apply to all instances of
1734 the same type of object. Such properties include:
1736 @item @code{direction}
1738 This has already been covered in some detail -- see
1739 @ref{Within-staff objects}.
1740 @item @code{padding}, @code{left-padding},
1741 @code{right-padding}, @code{staff-padding}
1743 @cindex left-padding property
1744 @cindex padding property
1745 @cindex right-padding property
1746 @cindex staff-padding property
1747 The @code{padding} property specifies the gap that must be left
1749 the top and bottom edges of objects which are positioned
1750 either above or below another previously placed object, or
1751 between the sides of objects which are positioned to the left or
1752 right of previously placed objects. @code{padding} can be applied
1753 to all objects which support the @code{side-position-interface}.
1755 Instead of @code{padding}, the placement of groups of accidentals
1756 is controlled by @code{left-padding} and @code{right-padding}.
1757 These properties are to be found in the @code{AccidentalPlacement}
1758 object which, note, lives in the @strong{staff} context.
1760 The @code{staff-padding} property is closely related to the
1761 @code{padding} property: @code{padding}
1762 controls the minimum amount of space between any object which
1763 supports the @code{side-position-interface} and the nearest
1764 other object (generally the note or the staff lines);
1765 @code{staff-padding} applies only to those objects which are always
1766 set outside the staff -- it controls the minimum amount of space
1767 that should be inserted between that object and the staff. Note
1768 that @code{staff-padding} has no effect on objects which are
1769 positioned relative to the note rather than the staff, even though
1770 it may be overridden without error for such objects -- it is simply
1773 To discover which padding property is required for the object
1774 you wish to reposition, you
1775 need to return to the IR and look up the object's properties.
1776 Be aware that the padding properties might not be located in the
1777 obvious object, so look in objects that appear to be related.
1779 All padding values are measured in staff spaces. For most
1780 objects, this value is set by default to be around 1.0 or less
1781 (it varies with each object). It may be overridden if a larger
1782 (or smaller) gap is required.
1784 @item @code{self-alignment-X}
1786 @cindex self-alignment-X property
1787 This property aligns the object to the left, to the right, or
1788 centers it with respect to the parent object's reference point.
1789 It may be used with all objects which support the
1790 @code{self-alignment-interface}. In general these are objects
1791 that contain text. The values are @code{LEFT}, @code{RIGHT}
1792 or @code{CENTER}. The movement is limited by the length of the
1793 object. Any numerical value between @code{-1} and @code{+1} may
1794 also be specified, where @code{-1} is left-aligned, @code{+1}
1795 is right-aligned, and numbers inbetween move the text progressively
1796 from left-aligned to right-aligned.
1798 @item @code{extra-spacing-width}
1800 @cindex extra-spacing-width property
1801 This property is available for all objects which support the
1802 @code{item-interface}. It takes two numbers, the first is added
1803 to the leftmost extent and the second is added to the rightmost
1804 extent. Negative numbers move the edge to the left, positive to
1805 the right, so to widen an object the first number must be negative,
1806 the second positive. Note that not all objects honour both
1807 numbers. For example, the @code{Accidental} object only takes
1808 notice of the first (left edge) number.
1810 @item @code{staff-position}
1812 @cindex staff-position property
1813 @code{staff-position} is a property of the
1814 @code{staff-symbol-referencer-interface}, which is supported by
1815 objects which are positioned relative to the staff. It specifies
1816 the vertical position of the object relative to the center line
1817 of the staff in half staff-spaces. It is useful in resolving
1818 collisions between layout objects like multi-measure rests, ties
1819 and notes in different voices.
1821 @item @code{force-hshift}
1823 @cindex force-hshift property
1825 TODO Move this explanation and add expanation of \shiftOn etc to
1826 Explicitly instantiating voices section in Fundamental concepts
1828 [Closely spaced notes in a chord, or notes occuring at the same
1829 time in different voices, are arranged in two, occasionally more,
1830 columns to prevent the noteheads overlapping. These are called
1831 note columns, and an object called @code{NoteColumn} is created
1832 to lay out the notes in that column. There are separate columns
1834 The @code{force-hshift}
1835 property is a property of a @code{NoteColumn} (actually of the
1836 @code{note-column-interface}). Changing it permits a note column
1837 to be moved in units appropriate to a note column, viz. the note
1838 head width of the first voice note. It should be used in
1839 complex situations where the normal @code{\shiftOn} commands (see
1840 @ref{Explicitly instantiating voices}) do
1841 not resolve the note conflict. It is preferable to the
1842 @code{extra-offset} property for this purpose as there is no need
1843 to work out the distance in staff-spaces, and moving the notes
1844 into or out of a @code{NoteColumn} affects other actions such as
1849 Objects do not all have all of these properties in general.
1850 It is necessary to go to the IR to look up which properties
1851 are available for the object in question.
1853 Finally, when all else fails, objects may be manually repositioned
1854 relative to the staff center line verically, or by
1855 displacing them by any distance to a new position. The
1856 disadvantages are that the correct values for the repositioning
1857 have to be worked out, often by trial and error, for every object
1858 individually, and, because the movement is done after LilyPond has
1859 placed all other objects, the user is responsible for avoiding any
1860 collisions that might ensue. But the main difficulty with this
1861 approach is that the repositioning values may need to be reworked
1862 if the music is later modified. The properties that can be used
1863 for this type of manual repositioning are:
1865 @item @code{extra-offset}
1867 @cindex extra-offset property
1868 This property applies to any layout object
1869 supporting the @code{grob-interface}. It takes a pair of
1870 numbers which specify the extra displacement in the horizontal and
1871 vertical directions. Negative numbers move the object to
1872 the left or down. The units are staff-spaces. The extra
1873 displacement is made after the typesetting of objects is
1874 finished, so an object may be repositioned anywhere without
1875 affecting anything else.
1877 @item @code{positions}
1879 @cindex positions property
1880 This is most useful for manually adjusting the slope and height
1881 of beams, slurs, and tuplets. It takes a pair of numbers
1882 giving the position of the left and right ends of the beam, slur,
1883 etc. relative to the center line of the staff. Units are
1888 Objects do not all have all of these properties in general.
1889 It is necessary to go to the IR to look up which properties
1890 are available for the object in question.
1894 Here is a list of the objects which are most likely to be
1895 involved in collisions, together with the name of the object which
1896 should be looked up in the IR in order to discover which properties
1897 should be used to move them.
1899 @multitable @columnfractions .5 .5
1900 @headitem Object type @tab Object name
1901 @item Articulations @tab @code{Script}
1902 @item Beams @tab @code{Beam}
1903 @item Dynamics (vertically) @tab @code{DynamicLineSpanner}
1904 @item Dynamics (horizontally) @tab @code{DynamicText}
1905 @item Fingerings @tab @code{Fingering}
1906 @item Rehearsal / Text marks @tab @code{RehearsalMark}
1907 @item Slurs @tab @code{Slur}
1908 @item Text e.g. @code{^"text"} @tab @code{TextScript}
1909 @item Ties @tab @code{Tie}
1910 @item Tuplets @tab @code{TupletBracket}
1914 @node Fixing overlapping notation
1915 @subsection Fixing overlapping notation
1917 Let's now see how the properties in the previous section can
1918 help to resolve overlapping notation.
1920 @subheading padding property
1921 @cindex padding property
1923 The @code{padding} property can be set to increase
1924 (or decrease) the distance between symbols that are printed
1925 above or below notes.
1927 @lilypond[quote,fragment,relative=1,verbatim]
1929 \override Script #'padding = #3
1933 @lilypond[quote,fragment,relative=1,verbatim]
1934 % This will not work, see below:
1935 \override MetronomeMark #'padding = #3
1939 \override Score.MetronomeMark #'padding = #3
1944 Note in the second example how important it is to figure out what
1945 context handles a certain object. Since the @code{MetronomeMark} object
1946 is handled in the @code{Score} context, property changes in the
1947 @code{Voice} context will not be noticed. For more details, see
1948 @ruser{Constructing a tweak}.
1950 @subheading left-padding and right-padding properties
1951 @cindex left-padding property
1952 @cindex right-padding property
1954 TODO Example of this - at the moment I can't find one! -td
1956 @subheading staff-padding property
1957 @cindex staff-padding property
1959 @code{staff-padding} can be used to align objects such as dynamics
1960 along a baseline at a fixed height above the staff, rather than
1961 at a height dependent on the position of the note to which they
1962 are attached. It is not a property of
1963 @code{DynamicText} but of @code{DynamicLineSpanner}.
1964 This is because the baseline should apply equally to @strong{all}
1965 dynamics, including those created as extended spanners.
1966 So this is the way to align the dynamic marks in the example
1967 taken from the previous section:
1969 @lilypond[quote,fragment,ragged-right,verbatim,relative=2]
1971 % Extend width by 1 unit
1972 \override DynamicText #'extra-spacing-width = #'(-0.5 . 0.5)
1973 % Align dynamics to a base line 2 units above staff
1974 \override DynamicLineSpanner #'staff-padding = #2
1979 @subheading self-alignment-X property
1980 @cindex self-alignment-X property
1982 The following example shows how this can resolve the collision
1983 of a string fingering object with a note's stem by aligning the
1984 right edge with the reference point of the parent note:
1986 @lilypond[quote,fragment,ragged-right,verbatim,relative=3]
1989 \once \override StringNumber #'self-alignment-X = #RIGHT
1993 @subheading staff-position property
1994 @cindex staff-position property
1996 Multimeasure rests in one voice can collide with notes in another.
1997 Since these rests are typeset centered between the bar lines, it
1998 would require significant effort for LilyPond to figure out which
1999 other notes might collide with it, since all the current collision
2000 handling between notes and between notes and rests is done only
2001 for notes and rests that occur at the same time. Here's an
2002 example of a collision of this type:
2004 @lilypond[quote,verbatim,fragment,ragged-right, relative=1]
2005 << {c c c c} \\ {R1} >>
2008 The best solution here is to move the multimeasure rest down,
2009 since the rest is in voice two.
2010 The default in @code{\voiceTwo} (i.e. in the second voice of a
2011 @code{<<@{...@} \\ @{...@}>>} construct)
2012 is that @code{staff-position} is set to -4 for MultiMeasureRest,
2013 so we need to move it, say, four half-staff spaces down to
2016 @lilypond[quote,verbatim,fragment,ragged-right, relative=1]
2020 \override MultiMeasureRest #'staff-position = #-8
2025 This is better than using, for example, @code{extra-offset},
2026 because the ledger line above the rest is inserted automatically.
2028 @subheading extra-offset property
2029 @cindex extra-offset property
2031 The @code{extra-offset} property provides complete control over the
2032 positioning of an object both horizontally and vertically.
2034 In the following example, the second fingering is moved a little to
2035 the left, and 1.8 staff space downwards:
2037 @lilypond[quote,fragment,relative=1,verbatim]
2040 \once \override Fingering
2041 #'extra-offset = #'(-0.3 . -1.8)
2046 @subheading force-hshift property
2047 @cindex force-hshift property
2048 @c FIXME: formatting stuff (ie not important right now IMO)
2049 @c @a nchor Chopin finally corrected TODOgp
2051 We can now see how to apply the final corrections to the Chopin
2052 example introduced at the end of @ref{I'm hearing Voices}, which
2053 was left looking like this:
2055 @lilypond[quote,verbatim,fragment,ragged-right]
2056 \new Staff \relative c'' {
2059 { c2 aes4. bes8 } \\
2071 The lower two notes of the first chord (i.e,
2072 those in the third voice) should not be shifted away from the
2073 note column of the higher two notes. To correct this we set
2074 @code{force-hshift}, which is a property of
2075 @code{NoteColumn}, of these notes to zero.
2076 The lower note of the second chord is best placed just to the
2077 right of the higher notes. We achieve this by setting
2078 @code{force-hshift} of this note to 0.5, ie half a notehead's
2079 width to the right of the note column of the higher notes.
2081 Here's the final result:
2083 @lilypond[quote,verbatim,fragment,ragged-right]
2084 \new Staff \relative c'' {
2087 { c2 aes4. bes8 } \\
2090 \once \override NoteColumn #'force-hshift = #0 <ees c>2
2091 \once \override NoteColumn #'force-hshift = #0.5 des2
2099 @subheading positions property
2100 @cindex positions property
2102 The @code{positions} property allows the position and slope of
2103 tuplets, slurs, phrasing slurs and beams to be controlled
2104 manually. Here's an example which has an ugly phrasing slur
2105 due to it trying to avoid the slur on the acciaccatura.
2107 @lilypond[quote,verbatim,fragment,ragged-right,relative=1]
2108 r4 \acciaccatura e8\( d8 c ~c d c d\)
2112 We could simply move the phrasing slur above the notes, and this
2113 would be the preferred solution:
2115 @lilypond[quote,verbatim,fragment,ragged-right,relative=1]
2118 \acciaccatura e8\( d8 c ~c d c d\)
2122 but if there were some reason why this could not be done the
2123 other alternative would be to move the left end of the phrasing
2124 slur down a little using the @code{positions} property. This
2125 also resolves the rather nasty shape.
2127 @lilypond[quote,verbatim,fragment,ragged-right,relative=1]
2129 \once \override PhrasingSlur #'positions = #'(-4 . -3)
2131 e8\( d8 c ~c d c d\)
2134 Here's a further example taken from the opening of the left-hand
2135 staff of Chopin's Prelude Op 28 No. 2. We see that the beam
2136 collides with the upper notes:
2138 @lilypond[quote,verbatim,fragment,ragged-right]
2141 << {b,8 ais, b, g,} \\ {e, g e, g} >>
2142 << {b,8 ais, b, g,} \\ {e, g e, g} >>
2147 This can only be resolved by manually moving both ends of the beam
2148 up from their position at 2 staff-spaces above the center line to,
2151 @lilypond[quote,verbatim,fragment,ragged-right]
2155 \override Beam #'positions = #'(3 . 3)
2160 << {b,8 ais, b, g,} \\ {e, g e, g} >>
2165 Note that the override continues to apply in the first voice of
2166 the second block of quavers, but not to any of the beams in the
2169 TODO Examples of real music showing collisions and their resolution
2173 @section Page layout
2176 * Introduction to layout::
2180 * Fitting music onto fewer pages::
2183 @node Introduction to layout
2184 @subsection Introduction to layout
2186 The global paper layout is determined by three factors:
2187 the page layout, the line breaks, and the spacing. These all
2188 influence each other. The choice of spacing determines how
2189 densely each system of music is set. This influences where line
2190 breaks are chosen, and thus ultimately, how many pages a piece
2193 Settings which influence layout may be placed in two blocks.
2194 The @code{\paper @{ ... @}} block is placed outside any
2195 @code{\score @{ ... @}} blocks and contains settings that
2196 relate to the entire document. The @code{\layout @{ ... @}}
2197 block is placed within a @code{\score @{ ... @}} block and
2198 contains settings for that particular score. If you have
2199 only one @code{\score @{ ... @}} block the two have the same
2200 effect. In general the commands shown in this section can
2201 be placed in either.
2203 Much more detail on the options for tweaking the laying out
2204 of music are contained in @ruser{Spacing issues}.
2207 @subsection Global sizes
2209 The default @strong{paper size} which LilyPond assumes in laying
2210 out the music is A4. This may be changed in two ways:
2213 #(set-default-paper-size "a6")
2216 #(set-paper-size "letter")
2221 The first command sets the size of all pages. The second command
2222 sets the size of the pages to which the \paper block applies
\96 if
2223 the \paper block is at the top of the file, then it will apply
2224 to all pages. Support for the following paper sizes are included:
2225 a6, a5, a4, a3, legal, letter, 11x17 (also known as tabloid).
2227 If the symbol @code{landscape} is supplied as an argument to
2228 @code{set-default-paper-size}, the pages will be rotated by 90
2229 degrees, and wider line widths will be set correspondingly, e.g.
2232 #(set-default-paper-size "a6" 'landscape)
2235 The default @strong{staff size} is set to 20 points.
2236 This may be changed in two ways:
2239 #(set-global-staff-size 14)
2242 #(set-global-staff-size 16)
2247 The first command sets the size in all pages. The second command
2248 sets the size in the pages to which the \paper block applies
\96 if
2249 the \paper block is at the top of the file, then it will apply
2250 to all pages. All the fonts are automatically scaled to suit
2251 the new value of the staff size.
2254 @subsection Line breaks
2256 Line breaks are normally computed automatically. They are chosen
2257 so that lines look neither cramped nor loose, and that consecutive
2258 lines have similar density. Occasionally you might want to
2259 override the automatic breaks; you can do this by specifying
2260 @code{\break}. This will force a line break at this point. Line
2261 breaks can only occur at the end of @q{complete} bars, i.e., where
2262 there are no notes or tuplets left @q{hanging} over the bar line.
2263 If you want to have a line break where there is no bar line, you
2264 can force an invisible bar line by entering @code{\bar ""}.
2265 Similarly, @code{\noBreak} forbids a line break at a point.
2267 The most basic settings influencing line spacing are @code{indent}
2268 and @code{line-width}. They are set in the @code{\layout} block.
2269 They control the indentation of the first line of music, and the
2270 lengths of the lines.
2272 If @code{ragged-right} is set to true in the @code{\layout} block,
2273 then systems end at their natural horizontal length, instead of
2274 being spread horizontally to fill the whole line. This is useful
2275 for short fragments, and for checking how tight the natural
2278 The option @code{ragged-last} is similar to @code{ragged-right},
2279 but only affects the last line of the piece.
2290 @subsection Page breaks
2292 The default page breaking may be overriden by inserting
2293 @code{\pageBreak} or @code{\noPageBreak} commands.
2294 These commands are analogous to @code{\break} and @code{\noBreak}.
2295 These commands force and forbid a page-break from happening.
2296 Of course, the @code{\pageBreak} command also forces a line break.
2297 Like @code{\break}, the @code{\pageBreak} command is effective only
2298 at the end of a @q{complete} bar as defined above. For more
2299 details see @ruser{Page breaking} and following sections.
2301 There are also analogous settings to @code{ragged-right} and
2302 @code{ragged-last} which have the same effect on vertical spacing:
2303 @code{ragged-bottom} and @code{ragged-last-bottom}. If set to
2304 @code{##t} the systems on all pages or just the last page
2305 respectively are not justified vertically.
2307 For more details see @ruser{Vertical spacing}.
2309 @node Fitting music onto fewer pages
2310 @subsection Fitting music onto fewer pages
2312 Sometimes you can end up with one or two staves on a second
2313 (or third, or fourth...) page. This is annoying, especially
2314 if you look at previous pages and it looks like there is plenty
2315 of room left on those.
2317 When investigating layout issues, @code{annotate-spacing} is
2318 an invaluable tool. This command prints the values of various
2319 layout spacing commands; see @ruser{Displaying spacing}, for more
2320 details. From the output of @code{annotate-spacing}, we can
2321 see which margins we may wish to alter.
2323 Other than margins, there are a few other options to save space:
2327 You may tell LilyPond to place systems as close together as
2328 possible (to fit as many systems as possible onto a page), but
2329 then to space those systems out so that there is no blank
2330 space at the bottom of the page.
2334 between-system-padding = #0.1
2335 between-system-space = #0.1
2336 ragged-last-bottom = ##f
2342 You may force the number of systems (i.e., if LilyPond wants
2343 to typeset some music with 11 systems, you could force it to
2353 Avoid (or reduce) objects which increase the vertical size of
2354 a system. For example, volta repeats (or alternate repeats)
2355 require extra space. If these repeats are spread over two
2356 systems, they will take up more space than one system with
2357 the volta repeats and another system without.
2359 Another example is moving dynamics which @q{stick out} of
2360 a system, as in the second bar here:
2362 @lilypond[verbatim,quote,fragment,ragged-right,relative=1]
2364 \override DynamicText #'extra-offset = #'( -2.2 . 2.0)
2369 Alter the horizontal spacing via @code{SpacingSpanner}. See
2370 @ruser{Changing horizontal spacing}, for more details. Here's
2371 an example first showing the default behaviour:
2373 @lilypond[verbatim,quote,ragged-right]
2386 and now with @code{common-shortest-duration} increased from the
2387 value of @code{1/4} (a quarter note is the most common in this
2388 example) to @code{1/2}:
2390 @lilypond[verbatim,quote,ragged-right]
2402 \override SpacingSpanner
2403 #'common-shortest-duration = #(ly:make-moment 1 2)
2410 Note that this override cannot be modified dynamically, so it must
2411 always be placed in a @code{\context@{..@}} block so that it applies
2414 TODO Add description of using \context in this way earlier if it is
2415 not already anywhere -td
2419 TODO Mention line-thickness somewhere else and move this there
2421 @cindex Tweaks, distances
2424 Distances in LilyPond are measured in staff-spaces, while most
2425 thickness properties are measured in line-thickness. Some
2426 properties are different; for example, the thickness of beams
2427 are measured in staff-spaces. For more information, see the
2428 relevant portion of the program reference.
2432 @node Further tweaking
2433 @section Further tweaking
2436 * Other uses for tweaks::
2437 * Other sources of information::
2438 * Advanced tweaks with Scheme::
2439 * Avoiding tweaks with slower processing::
2442 @node Other uses for tweaks
2443 @subsection Other uses for tweaks
2448 Setting the @code{transparent} property will cause an object to be printed
2449 in @q{invisible ink}: the object is not printed, but all its other
2450 behavior is retained. The object still takes up space, it takes part in
2451 collisions, and slurs, ties, and beams can be attached to it.
2453 @cindex transparent objects
2454 @cindex removing objects
2455 @cindex hiding objects
2456 @cindex invisible objects
2457 The following example demonstrates how to connect different voices
2458 using ties. Normally, ties only connect two notes in the same
2459 voice. By introducing a tie in a different voice,
2461 @lilypond[quote,fragment,relative=2]
2470 and blanking the first up-stem in that voice, the tie appears to cross
2473 @lilypond[quote,fragment,relative=2,verbatim]
2475 \once \override Stem #'transparent = ##t
2482 To make sure that the just-blanked stem doesn't squeeze the tie too much,
2483 we also lengthen the stem, by setting the @code{length} to
2486 @lilypond[quote,fragment,relative=2,verbatim]
2488 \once \override Stem #'transparent = ##t
2489 \once \override Stem #'length = #8
2499 @node Other sources of information
2500 @subsection Other sources of information
2502 The Internals Reference documentation contains a lot of information
2503 about LilyPond, but even more information can be gathered from
2504 looking at the internal LilyPond files.
2506 TODO Show example, then explain where to find ly/propert-ly.
2508 Some default settings (such as the definitions for
2509 @code{\header@{@}}s) are stored as @code{.ly} files. Other
2510 settings (such as the definitions of markup commands) are
2511 stored as @code{.scm} (Scheme) files. Further explanation is
2512 outside the scope of this manual; users should be warned that
2513 a substantial amount of technical knowledge or time is required
2514 to understand these files.
2518 @item Linux: @file{@var{installdir}/lilypond/usr/share/lilypond/current/}
2521 @file{@var{installdir}/LilyPond.app/Contents/Resources/share/lilypond/current/}.
2522 To access this, either @code{cd} into this directory from the
2523 Terminal, or control-click on the LilyPond application and select
2524 @q{Show Package Contents}.
2526 @item Windows: @file{@var{installdir}/LilyPond/usr/share/lilypond/current/}
2530 The @file{ly/} and @file{scm/} directories will be of
2531 particular interest. Files such as @file{ly/property-init.ly} and
2532 @file{ly/declarations-init.ly} define all the common tweaks.
2535 @node Advanced tweaks with Scheme
2536 @subsection Advanced tweaks with Scheme
2538 We have seen how LilyPond output can be heavily modified using
2540 @code{\override TextScript #'extra-offset = ( 1 . -1)}. But
2541 we have even more power if we use Scheme. For a full explantion
2542 of this, see the @ref{Scheme tutorial}, and
2543 @ruser{Interfaces for programmers}.
2545 We can use Scheme to simply @code{\override} commands,
2547 TODO Check this is a valid example with skylining
2549 @lilypond[quote,verbatim,ragged-right]
2550 padText = #(define-music-function (parser location padding) (number?)
2552 \once \override TextScript #'padding = #$padding
2556 c4^"piu mosso" b a b
2558 c4^"piu mosso" d e f
2560 c4^"piu mosso" fis a g
2564 We can use it to create new commands,
2566 TODO Check this is a valid example with skylining
2568 @lilypond[quote,verbatim,ragged-right]
2569 tempoMark = #(define-music-function (parser location padding marktext)
2572 \once \override Score . RehearsalMark #'padding = $padding
2573 \once \override Score . RehearsalMark #'extra-spacing-width = #'(+inf.0 . -inf.0)
2574 \mark \markup { \bold $marktext }
2579 \tempoMark #3.0 #"Allegro"
2584 Even music expressions can be passed in.
2586 @lilypond[quote,verbatim,ragged-right]
2587 pattern = #(define-music-function (parser location x y) (ly:music? ly:music?)
2594 \pattern {d16 dis} { ais16-> b\p }
2599 @node Avoiding tweaks with slower processing
2600 @subsection Avoiding tweaks with slower processing
2602 LilyPond can perform extra checks while it processes files. These
2603 commands will take extra time, but the result may require fewer
2607 %% makes sure text scripts and lyrics are within the paper margins
2608 \override Score.PaperColumn #'keep-inside-line = ##t
2609 \override Score.NonMusicalPaperColumn #'keep-inside-line = ##t
2612 In some cases (see issue 246), this must be done before
2613 @code{\override} commands can be processed.
2617 \override PaperColumn #'keep-inside-line = ##t
2618 \override NonMusicalPaperColumn #'keep-inside-line = ##t