1 @c -*- coding: latin-1; mode: texinfo; -*-
2 @c This file is part of lilypond.tely
10 * Automated engraving::
11 * What symbols to engrave?::
12 * Music representation::
13 * Example applications::
21 The art of music typography is called @emph{(plate) engraving}. The
22 term derives from the traditional process of music printing. Just a
23 few decades ago, sheet music was made by cutting and stamping the
24 music into a zinc or pewter plate in mirror image. The plate would be
25 inked, the depressions caused by the cutting and stamping would hold
26 ink. An image was formed by pressing paper to the plate. The
27 stamping and cutting was completely done by hand. Making a correction
28 was cumbersome, if possible at all, so the engraving had to be perfect
29 in one go. Engraving was a highly specialized skill; a craftsman had
30 to complete around five years of training before earning the title of
31 master engraver, and another five years of experience were
32 necessary to become truly skilled.
34 Nowadays, all newly printed music is produced with computers. This
35 has obvious advantages; prints are cheaper to make, and editorial work
36 can be delivered by email. Unfortunately, the pervasive use of
37 computers has also decreased the graphical quality of scores.
38 Computer printouts have a bland, mechanical look, which makes them
39 unpleasant to play from.
42 @c introduce illustrating aspects of engraving, font...
43 The images below illustrate the difference between traditional
44 engraving and typical computer output, and the third picture shows how
45 LilyPond mimics the traditional look. The left picture shows a scan
46 of a flat symbol from an edition published in 2000. The center
47 depicts a symbol from a hand-engraved B@"{a}renreiter edition of the
48 same music. The left scan illustrates typical flaws of computer
49 print: the staff lines are thin, the weight of the flat symbol matches
50 the light lines and it has a straight layout with sharp corners. By
51 contrast, the B@"{a}renreiter flat has a bold, almost voluptuous
52 rounded look. Our flat symbol is designed after, among others, this
53 one. It is rounded, and its weight harmonizes with the thickness of
54 our staff lines, which are also much thicker than lines in the
57 @multitable @columnfractions .05 .3 .3 .3 .05
61 @image{henle-flat-bw,4cm}
64 @image{henle-flat-bw,,,png}
69 @image{baer-flat-bw,4cm}
72 @image{baer-flat-bw,,,png}
77 @image{lily-flat-bw,4cm}
80 @image{lily-flat-bw,,,png}
84 @c workaround for makeinfo-4.6: line breaks and multi-column cookies
85 @image{henle-flat-bw,,,png} @image{baer-flat-bw,,,png} @image{lily-flat-bw,,,png}
91 B@"{a}renreiter (1950)
93 LilyPond Feta font (2003)
98 @cindex musical symbols
103 @c introduce illustrating aspects of engraving, spacing...
104 In spacing, the distribution of space should reflect the durations
105 between notes. However, many modern scores adhere to the durations
106 with mathematical precision, which leads to poor results. In the
107 next example a motive is printed twice. It is printed once using
108 exact mathematical spacing, and once with corrections. Can you
109 spot which fragment is which?
111 @cindex optical spacing
112 @lilypond[quote,noindent,fragment]
114 \override Staff.NoteSpacing #'stem-spacing-correction = #0.6
116 \stemDown b'4 e''4 a'4 e''4 | \bar "||"
117 \override Staff.NoteSpacing #'stem-spacing-correction = #0.0
118 \override Staff.StaffSpacing #'stem-spacing-correction = #0.0
119 \stemNeutral c'4 e''4 e'4 b'4 |
120 \stemDown b'4 e''4 a'4 e''4 |
124 @cindex regular rhythms
125 @cindex regular spacing
127 The fragment only uses quarter notes: notes that are played in a
128 constant rhythm. The spacing should reflect that. Unfortunately, the
129 eye deceives us a little; not only does it notice the distance between
130 note heads, it also takes into account the distance between
131 consecutive stems. As a result, the notes of an up-stem/@/down-stem
132 combination should be put farther apart, and the notes of a down-stem/@/up-stem
133 combination should be put closer together, all depending on the
134 combined vertical positions of the notes. The first two measures are
135 printed with this correction, the last two measures without. The notes
136 in the last two measures form down-stem/@/up-stem clumps of notes.
140 Musicians are usually more absorbed with performing than with studying
141 the looks of a piece of music, so nitpicking about typographical details
142 may seem academical. But it is not. In larger pieces with monotonous
143 rhythms, spacing corrections lead to subtle variations in the layout
144 of every line, giving each one a distinct visual signature. Without
145 this signature all lines would look the same, and they become like a
146 labyrinth. If a musician looks away once or has a lapse in
147 concentration, the lines might lose their place on the page.
149 Similarly, the strong visual look of bold symbols on heavy staff lines
150 stands out better when the music is far away from the reader, for example,
151 if it is on a music stand. A careful distribution of white space allows
152 music to be set very tightly without cluttering symbols together. The
153 result minimizes the number of page turns, which is a great advantage.
155 This is a common characteristic of typography. Layout should be
156 pretty, not only for its own sake, but especially because it helps the
157 reader in her task. For performance material like sheet music, this is
158 of double importance: musicians have a limited amount of attention. The
159 less attention they need for reading, the more they can focus on
160 playing the music. In other words, better typography translates to better
163 These examples demonstrate that music typography is an art that is
164 subtle and complex, and that producing it requires considerable
165 expertise, which musicians usually do not have. LilyPond is our
166 effort to bring the graphical excellence of hand-engraved music to the
167 computer age, and make it available to normal musicians. We have
168 tuned our algorithms, font-designs, and program settings to produce
169 prints that match the quality of the old editions we love to see and
175 @node Automated engraving
176 @section Automated engraving
178 How do we go about implementing typography? If craftsmen need over
179 ten years to become true masters, how could we simple hackers ever
180 write a program to take over their jobs?
182 The answer is: we cannot. Typography relies on human judgment of
183 appearance, so people cannot be replaced completely. However, much of
184 the dull work can be automated. If LilyPond solves most of the common
185 situations correctly, this will be a huge improvement over existing
186 software. The remaining cases can be tuned by hand. Over the course
187 of years, the software can be refined to do more and more things
188 automatically, so manual overrides are less and less necessary.
190 When we started, we wrote the LilyPond program entirely in the C++
191 programming language; the program's functionality was set in stone by
192 the developers. That proved to be unsatisfactory for a number of
196 @item When LilyPond makes mistakes,
197 users need to override formatting decisions. Therefore, the user must
198 have access to the formatting engine. Hence, rules and settings cannot
199 be fixed by us at compile-time but must be accessible for users at
202 @item Engraving is a matter of visual judgment, and therefore a matter of
203 taste. As knowledgeable as we are, users can disagree with our
204 personal decisions. Therefore, the definitions of typographical style
205 must also be accessible to the user.
207 @item Finally, we continually refine the formatting algorithms, so we
208 need a flexible approach to rules. The C++ language forces a certain
209 method of grouping rules that do not match well with how music
213 These problems have been addressed by integrating an interpreter for
214 the Scheme programming language and rewriting parts of LilyPond in
215 Scheme. The current formatting architecture is built around the
216 notion of graphical objects, described by Scheme variables and
217 functions. This architecture encompasses formatting rules,
218 typographical style and individual formatting decisions. The user has
219 direct access to most of these controls.
221 Scheme variables control layout decisions. For example, many
222 graphical objects have a direction variable that encodes the choice
223 between up and down (or left and right). Here you see two chords,
224 with accents and arpeggios. In the first chord, the graphical objects
225 have all directions down (or left). The second chord has all
226 directions up (right).
228 @lilypond[quote,raggedright]
230 \override SpacingSpanner #'spacing-increment = #3
231 \override TimeSignature #'transparent = ##t
233 \stemDown <e g b>4_>-\arpeggio
234 \override Arpeggio #'direction = #RIGHT
235 \stemUp <e g b>4^>-\arpeggio
240 The process of formatting a score consists of reading and writing the
241 variables of graphical objects. Some variables have a preset value. For
242 example, the thickness of many lines -- a characteristic of typographical
243 style -- is a variable with a preset value. You are free to alter this
244 value, giving your score a different typographical impression.
246 @lilypond[quote,raggedright]
249 c'4-~ c'16 as g f e16 g bes c' des'4
254 \override Beam #'thickness = #0.3
255 \override Stem #'thickness = #0.5
256 \override Bar #'thickness = #3.6
257 \override Tie #'thickness = #2.2
258 \override StaffSymbol #'thickness = #3.0
259 \override Tie #'extra-offset = #'(0 . 0.3)
265 Formatting rules are also preset variables: each object has variables
266 containing procedures. These procedures perform the actual
267 formatting, and by substituting different ones, we can change the
268 appearance of objects. In the following example, the rule which note
269 head objects are used to produce their symbol is changed during the music
272 @c FIXME: this example has errors:
273 @c programming error: Grob `NoteHead' has no interface for property `text'
274 @c Continuing; crossing fingers
275 @lilypond[quote,raggedright]
276 #(define (mc-squared grob orig current)
277 (let ((interfaces (ly:grob-property grob 'interfaces))
278 (pos (ly:grob-property grob 'staff-position)))
279 (if (and (memq 'note-head-interface interfaces)
280 (memq pos '(-2 -3 -5)))
282 (ly:grob-set-property! grob 'print-function Text_interface::print)
283 (ly:grob-set-property! grob 'font-family 'roman)
284 (ly:grob-set-property!
289 ((-5) (make-simple-markup "m"))
290 ((-3) (make-simple-markup "c "))
291 ((-2) (make-smaller-markup (make-bold-markup "2")))
292 (else (make-simple-markup "bla")))))))))
294 \new Voice \relative c' {
296 \set autoBeaming = ##f
299 \once \override NoteHead #'print-function = #Note_head::brew_ez_stencil
301 \once \override NoteHead #'style = #'cross
303 \applyoutput #mc-squared
306 { d8[ es-( fis^^ g] fis2-) }
307 \repeat unfold 5 { \applyoutput #mc-squared s8 }
314 @node What symbols to engrave?
315 @section What symbols to engrave?
320 The formatting process decides where to place
321 symbols. However, this can only be done once it is decided @emph{what}
322 symbols should be printed, in other words what notation to use.
324 Common music notation is a system of recording music that has evolved
325 over the past 1000 years. The form that is now in common use dates
326 from the early renaissance. Although the basic form (i.e., note heads on a
327 5-line staff) has not changed, the details still evolve to express the
328 innovations of contemporary notation. Hence, it encompasses some 500
329 years of music. Its applications range from monophonic melodies to
330 monstrous counterpoints for large orchestras.
332 How can we get a grip on such a many-headed beast, and force it into
333 the confines of a computer program? Our solution is to break up the
334 problem of notation (as opposed to engraving, i.e., typography) into
335 digestible and programmable chunks: every type of symbol is handled by
336 a separate module, a so-called plug-in. Each plug-in is completely
337 modular and independent, so each can be developed and improved
338 separately. Such plug-ins are called @code{engraver}s, by analogy with
339 craftsmen who translate musical ideas to graphic symbols.
341 In the following example, we see how we start out with a plug-in for
342 note heads, the @code{Note_heads_engraver}.
344 @lilypond[quote,raggedright]
345 \include "engraver-example.ily"
352 \remove "Stem_engraver"
353 \remove "Phrasing_slur_engraver"
354 \remove "Slur_engraver"
355 \remove "Script_engraver"
356 \remove "Beam_engraver"
357 \remove "Auto_beam_engraver"
361 \remove "Accidental_engraver"
362 \remove "Key_engraver"
363 \remove "Clef_engraver"
364 \remove "Bar_engraver"
365 \remove "Time_signature_engraver"
366 \remove "Staff_symbol_engraver"
367 \consists "Pitch_squash_engraver"
374 Then a @code{Staff_symbol_engraver} adds the staff
376 @lilypond[quote,raggedright]
377 \include "engraver-example.ily"
384 \remove "Stem_engraver"
385 \remove "Phrasing_slur_engraver"
386 \remove "Slur_engraver"
387 \remove "Script_engraver"
388 \remove "Beam_engraver"
389 \remove "Auto_beam_engraver"
393 \remove "Accidental_engraver"
394 \remove "Key_engraver"
395 \remove "Clef_engraver"
396 \remove "Bar_engraver"
397 \consists "Pitch_squash_engraver"
398 \remove "Time_signature_engraver"
405 the @code{Clef_engraver} defines a reference point for the staff
407 @lilypond[quote,raggedright]
408 \include "engraver-example.ily"
415 \remove "Stem_engraver"
416 \remove "Phrasing_slur_engraver"
417 \remove "Slur_engraver"
418 \remove "Script_engraver"
419 \remove "Beam_engraver"
420 \remove "Auto_beam_engraver"
424 \remove "Accidental_engraver"
425 \remove "Key_engraver"
426 \remove "Bar_engraver"
427 \remove "Time_signature_engraver"
434 and the @code{Stem_engraver} adds stems.
436 @lilypond[quote,raggedright]
437 \include "engraver-example.ily"
444 \remove "Phrasing_slur_engraver"
445 \remove "Slur_engraver"
446 \remove "Script_engraver"
447 \remove "Beam_engraver"
448 \remove "Auto_beam_engraver"
452 \remove "Accidental_engraver"
453 \remove "Key_engraver"
454 \remove "Bar_engraver"
455 \remove "Time_signature_engraver"
461 The @code{Stem_engraver} is notified of any note head coming along.
462 Every time one (or more, for a chord) note head is seen, a stem
463 object is created and connected to the note head. By adding
464 engravers for beams, slurs, accents, accidentals, bar lines,
465 time signature, and key signature, we get a complete piece of
468 @lilypond[quote,raggedright]
469 \include "engraver-example.ily"
473 This system works well for monophonic music, but what about
474 polyphony? In polyphonic notation, many voices can share a staff.
476 @lilypond[quote,raggedright]
477 \include "engraver-example.ily"
478 \new Staff << \topVoice \\ \botVoice >>
481 In this situation, the accidentals and staff are shared, but the stems,
482 slurs, beams, etc., are private to each voice. Hence, engravers should
483 be grouped. The engravers for note heads, stems, slurs, etc., go into a
484 group called `Voice context,' while the engravers for key, accidental,
485 bar, etc., go into a group called `Staff context.' In the case of
486 polyphony, a single Staff context contains more than one Voice context.
487 Similarly, multiple Staff contexts can be put into a single Score
488 context. The Score context is the top level notation context.
492 Program reference: @internalsref{Contexts}.
494 @lilypond[quote,raggedright]
495 \include "engraver-example.ily"
498 \new Staff << \topVoice \\ \botVoice >>
499 \new Staff << \pah \\ \hoom >>
504 @node Music representation
505 @section Music representation
507 Ideally, the input format for any high-level formatting system is an
508 abstract description of the content. In this case, that would be the
509 music itself. This poses a formidable problem: how can we define what
510 music really is? Instead of trying to find an answer, we have reversed
511 the question. We write a program capable of producing sheet music,
512 and adjust the format to be as lean as possible. When the format can
513 no longer be trimmed down, by definition we are left with content
514 itself. Our program serves as a formal definition of a music
517 The syntax is also the user-interface for LilyPond, hence it is easy
525 a quarter note C1 (middle C) and an eighth note D1 (D above middle C)
527 @lilypond[quote,fragment]
531 On a microscopic scale, such syntax is easy to use. On a larger
532 scale, syntax also needs structure. How else can you enter complex
533 pieces like symphonies and operas? The structure is formed by the
534 concept of music expressions: by combining small fragments of music
535 into larger ones, more complex music can be expressed. For example
537 @lilypond[quote,verbatim,fragment,relative=1]
542 Chords can be constructed with @code{<<} and @code{>>} enclosing the notes
544 @c < > is not a music expression,
545 @c so we use <<>> iso. <> to drive home the point of
546 @c expressions. Don't change this back --hwn.
551 @lilypond[quote,fragment,relative=1]
552 \new Voice { <<c4 d4 e>> }
556 This expression is put in sequence by enclosing it in curly braces
557 @code{@{@tie{}@dots{}@tie{}@}}
560 @{ f4 <<c4 d4 e4>> @}
563 @lilypond[quote,relative=1,fragment]
568 The above is also an expression, and so it may be combined
569 again with another simultaneous expression (a half note) using <<,
573 << g2 \\ @{ f4 <<c4 d4 e4>> @} >>
576 @lilypond[quote,fragment,relative=2]
577 \new Voice { << g2 \\ { f4 <<c d e>> } >> }
580 Such recursive structures can be specified neatly and formally in a
581 context-free grammar. The parsing code is also generated from this
582 grammar. In other words, the syntax of LilyPond is clearly and
583 unambiguously defined.
585 User-interfaces and syntax are what people see and deal with
586 most. They are partly a matter of taste, and also subject of much
587 discussion. Although discussions on taste do have their merit, they
588 are not very productive. In the larger picture of LilyPond, the
589 importance of input syntax is small: inventing neat syntax is easy, while
590 writing decent formatting code is much harder. This is also
591 illustrated by the line-counts for the respective components: parsing
592 and representation take up less than 10% of the source code.
595 @node Example applications
596 @section Example applications
598 We have written LilyPond as an experiment of how to condense the art
599 of music engraving into a computer program. Thanks to all that hard
600 work, the program can now be used to perform useful tasks. The
601 simplest application is printing notes.
603 @lilypond[quote,relative=1,fragment]
604 \time 2/4 c4 c g'4 g a4 a g2
608 By adding chord names and lyrics we obtain a lead sheet.
610 @lilypond[quote,raggedright]
612 \chords { c2 c f2 c }
613 \new Staff \relative c' { \time 2/4 c4 c g'4 g a4 a g2 }
614 \new Lyrics \lyricmode { twin4 kle twin kle lit tle star2 }
618 Polyphonic notation and piano music can also be printed. The following
619 example combines some more exotic constructs.
621 @lilypondfile[quote,raggedright]{screech-boink.ly}
623 The fragments shown above have all been written by hand, but that is
624 not a requirement. Since the formatting engine is mostly automatic, it
625 can serve as an output means for other programs that manipulate
626 music. For example, it can also be used to convert databases of
627 musical fragments to images for use on websites and multimedia
630 This manual also shows an application: the input format is text, and
631 can therefore be easily embedded in other text-based formats such as
632 La@TeX{}, HTML, or in the case of this manual, Texinfo. By means of a
633 special program, the input fragments can be replaced by music images
634 in the resulting PDF or HTML output files. This makes it easy
635 to mix music and text in documents.
639 @node About this manual
640 @section About this manual
642 The manual is divided into the following chapters:
649 @emph{@ref{Tutorial}}
650 gives a gentle introduction to typesetting music. First time
651 users should start here.
657 @emph{@ref{Example templates}}
658 provides templates of LilyPond pieces. Just cut and paste a
659 template into a file, add notes, and you're done!
665 @c @emph{@ref{Notation manual}} @c FIXME
666 @emph{Notation manual}
667 discusses topics grouped by notation construct. Once you master the
668 basics, this is the place to look up details.
674 @emph{@ref{Changing defaults}}
675 explains how to fine tune layout.
681 @emph{@ref{Running LilyPond}} shows how to run LilyPond and its helper
688 @emph{@ref{LilyPond-book}} explains the details behind creating
689 documents with in-line music examples (like this manual).
695 @emph{@ref{Converting from other formats}}
696 explains how to run the conversion programs. These programs
697 are supplied with the LilyPond package, and convert a variety of music
698 formats to the @code{.ly} format. In addition, this section explains
699 how to upgrade input files from previous versions of LilyPond.
705 @emph{@ref{Literature list}}
706 contains a set of useful reference books for those who wish to know
707 more on notation and engraving.
710 Once you are an experienced user, you can use the manual as reference:
711 there is an extensive index@footnote{If you are looking for something,
712 and you cannot find it in the manual, that is considered a bug. In
713 that case, please file a bug report.}, but the document is also
719 @uref{source/Documentation/user/out-www/lilypond.html, one big page},
721 which can be searched easily using the search facility of a web
723 @cindex search in manual
724 @cindex using the manual
727 @c add/integrate glossary, put in list above
728 If you are not familiar with music notation or music terminology
729 (especially if you are a non-native English speaker), it is advisable
730 to consult the glossary as well.
732 The music glossary explains musical terms, and includes translations
733 to various languages. It is a separate document, available in HTML
737 The @ref{music-glossary,Music glossary,,music-glossary}, explains musical terms and
738 includes translations to various languages. It is also available in
744 @cindex foreign languages
748 This manual is not complete without a number of other documents. They
749 are not available in print, but should be included with the
750 documentation package for your platform
758 @ref{lilypond-internals,Program reference,,lilypond-internals}.
761 The program reference is a set of heavily cross linked HTML pages,
762 which document the nitty-gritty details of each and every LilyPond
763 class, object, and function. It is produced directly from the
764 formatting definitions used.
766 Almost all formatting functionality that is used internally, is
767 available directly to the user. For example, all variables that
768 control thickness values, distances, etc., can be changed in input
769 files. There are a huge number of formatting options, and all of them
770 are described in this document. Each section of the
771 notation manual has a @b{See also} subsection, which refers to the
772 generated documentation. In the HTML document, these subsections
773 have clickable links.
777 Various input examples.
780 @c Works, but link name is not so nice; so write-out macro
781 @c @inputfileref{input/test,Various input examples}.
782 @uref{source/input/test/out-www/collated-files.html,Various input examples}.
786 This collection of files shows various tips and tricks, and is
787 available as a big HTML document, with pictures and explanatory texts
792 The regression tests.
795 @c Works, but link name is not so nice; so write-out macro
796 @c @inputfileref{input/regression,The regression tests}.
797 @uref{source/input/regression/out-www/collated-files.html,The regression tests}.
800 This collection of files tests each notation and engraving feature of
801 LilyPond in one file. The collection is primarily there to help us
802 debug problems, but it can be instructive to see how we exercise the
803 program. The format is similar to the tips and tricks document.
807 In all HTML documents that have music fragments embedded, the LilyPond
808 input that was used to produce that image can be viewed by clicking
811 The location of the documentation files that are mentioned here can
812 vary from system to system. On occasion, this manual refers to
813 initialization and example files. Throughout this manual, we refer to
814 input files relative to the top-directory of the source archive. For
815 example, @file{input/@/test/@/bla@/.ly} may refer to the file
816 @file{lilypond@/-2.4.0/@/input/@/test/@/bla@/.ly}. On binary packages
817 for the Unix platform, the documentation and examples can typically be
818 found somewhere below @file{/usr/@/share/@/doc/@/lilypond/}.
819 Initialization files, for example @file{scm/@/lily@/.scm}, or
820 @file{ly/@/engraver@/-init@/.ly}, are usually found in the directory
821 @file{/usr/@/share/@/lilypond/}.
823 @cindex adjusting output
826 @cindex lilypond-internals
827 @cindex internal documentation
829 @cindex extending lilypond
833 Finally, this and all other manuals, are available online both as PDF
834 files and HTML from the web site, which can be found at
835 @uref{http://@/www@/.lilypond@/.org/}.