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 a Henle 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 Henle's lines.
56 @multitable @columnfractions .05 .3 .3 .3 .05
60 @image{henle-flat-bw,4cm}
63 @image{henle-flat-bw,,,png}
68 @image{baer-flat-bw,4cm}
71 @image{baer-flat-bw,,,png}
76 @image{lily-flat-bw,4cm}
79 @image{lily-flat-bw,,,png}
83 @c workaround for makeinfo-4.6: line breaks and multi-column cookies
84 @image{henle-flat-bw,,,png} @image{baer-flat-bw,,,png} @image{lily-flat-bw,,,png}
90 B@"{a}renreiter (1950)
92 LilyPond Feta font (2003)
97 @cindex musical symbols
102 @c introduce illustrating aspects of engraving, spacing...
103 In spacing, the distribution of space should reflect the durations
104 between notes. However, many modern scores adhere to the durations
105 with mathematical precision, which leads to poor results. In the
106 next example a motive is printed twice. It is printed once using
107 exact mathematical spacing, and once with corrections. Can you
108 spot which fragment is which?
110 @cindex optical spacing
111 @lilypond[quote,noindent,fragment]
113 \override Staff.NoteSpacing #'stem-spacing-correction = #0.6
115 \stemDown b'4 e''4 a'4 e''4 | \bar "||"
116 \override Staff.NoteSpacing #'stem-spacing-correction = #0.0
117 \override Staff.StaffSpacing #'stem-spacing-correction = #0.0
118 \stemBoth c'4 e''4 e'4 b'4 |
119 \stemDown b'4 e''4 a'4 e''4 |
123 @cindex regular rhythms
124 @cindex regular spacing
126 The fragment only uses quarter notes: notes that are played in a
127 constant rhythm. The spacing should reflect that. Unfortunately, the
128 eye deceives us a little; not only does it notice the distance between
129 note heads, it also takes into account the distance between
130 consecutive stems. As a result, the notes of an up-stem/down-stem
131 combination should be put farther apart, and the notes of a down-up
132 combination should be put closer together, all depending on the
133 combined vertical positions of the notes. The first two measures are
134 printed with this correction, the last two measures without. The notes
135 in the last two measures form down-stem/up-stem clumps of notes.
139 Musicians are usually more absorbed with performing than with studying
140 the looks of piece of music, so nitpicking about typographical details
141 may seem academical. But it is not. In larger pieces with monotonous
142 rhythms, spacing corrections lead to subtle variations in the layout
143 of every line, giving each one a distinct visual signature. Without
144 this signature all lines would look the same, and they become like a
145 labyrinth. If a musician looks away once or has a lapse in
146 concentration, they might lose their place on the page.
148 Similarly, the strong visual look of bold symbols on heavy staff lines
149 stands out better when music is far away from reader, for example, if
150 it is on a music stand. A careful distribution of white space allows
151 music to be set very tightly without cluttering symbols together. The
152 result minimizes the number of page turns, which is a great advantage.
154 This is a common characteristic of typography. Layout should be
155 pretty, not only for its own sake, but especially because it helps the
156 reader in her task. For performance material like sheet music, this is
157 of double importance: musicians have a limited amount of attention. The
158 less attention they need for reading, the more they can focus on
159 playing itself. In other words, better typography translates to better
162 These examples demonstrate that music typography is an art that is
163 subtle and complex, and that producing it requires considerable
164 expertise, which musicians usually do not have. LilyPond is our
165 effort to bring the graphical excellence of hand-engraved music to the
166 computer age, and make it available to normal musicians. We have
167 tuned our algorithms, font-designs, and program settings to produce
168 prints that match the quality of the old editions we love to see and
174 @node Automated engraving
175 @section Automated engraving
177 How do we go about implementing typography? If craftsmen need over
178 ten years to become true masters, how could we simple hackers ever
179 write a program to take over their jobs?
181 The answer is: we cannot. Typography relies on human judgment of
182 appearance, so people cannot be replaced completely. However, much of
183 the dull work can be automated. If LilyPond solves most of the common
184 situations correctly, this will be a huge improvement over existing
185 software. The remaining cases can be tuned by hand. Over the course
186 of years, the software can be refined to do more and more
187 automatically, so manual overrides are less and less necessary.
189 When we started we wrote the LilyPond program entirely in the C++
190 programming language; the program's functionality was set in stone by
191 the developers. That proved to be unsatisfactory for a number of
195 @item When LilyPond makes mistakes,
196 users need to override formatting decisions. Therefore, the user must
197 have access to the formatting engine. Hence, rules and settings cannot
198 be fixed by us at compile time but must be accessible for users at
201 @item Engraving is a matter of visual judgment, and therefore a matter of
202 taste. As knowledgeable as we are, users can disagree with our
203 personal decisions. Therefore, the definitions of typographical style
204 must also be accessible to the user.
206 @item Finally, we continually refine the formatting algorithms, so we
207 need a flexible approach to rules. The C++ language forces a certain
208 method of grouping rules that do not match well with how music
212 These problems have been addressed by integrating an interpreter for
213 the Scheme programming language and rewriting parts of LilyPond in
214 Scheme. The current formatting architecture is built around the
215 notion of graphical objects, described by Scheme variables and
216 functions. This architecture encompasses formatting rules,
217 typographical style and individual formatting decisions. The user has
218 direct access to most of these controls.
220 Scheme variables control layout decisions. For example, many
221 graphical objects have a direction variable that encodes the choice
222 between up and down (or left and right). Here you see two chords,
223 with accents and arpeggio. In the first chord, the graphical objects
224 have all directions down (or left). The second chord has all
225 directions up (right).
227 @lilypond[quote,raggedright,relative=1,fragment]
229 \override SpacingSpanner #'spacing-increment = #3
230 \override TimeSignature #'transparent = ##t
232 \stemDown <e g b>4_>-\arpeggio
233 \override Arpeggio #'direction = #RIGHT
234 \stemUp <e g b>4^>-\arpeggio
239 The process of formatting a score consists of reading and writing the
240 variables of graphical objects. Some variables have a preset value. For
241 example, the thickness of many lines -- a characteristic of typographical
242 style -- is a variable with a preset value. You are free to alter this
243 value, giving your score a different typographical impression.
245 @lilypond[quote,raggedright]
248 c'4-~ c'16 as g f e16 g bes c' des'4
253 \override Beam #'thickness = #0.3
254 \override Stem #'thickness = #0.5
255 \override Bar #'thickness = #3.6
256 \override Tie #'thickness = #2.2
257 \override StaffSymbol #'thickness = #3.0
258 \override Tie #'extra-offset = #'(0 . 0.3)
264 Formatting rules are also preset variables: each object has variables
265 containing procedures. These procedures perform the actual
266 formatting, and by substituting different ones, we can change the
267 appearance of objects. In the following example, the rule which note
268 head objects use to produce their symbol is changed during the music
271 @c FIXME: this example has errors:
272 @c programming error: Grob `NoteHead' has no interface for property `text'
273 @c Continuing; crossing fingers
274 @lilypond[quote,raggedright]
275 #(define (mc-squared grob orig current)
276 (let ((interfaces (ly:grob-property grob 'interfaces))
277 (pos (ly:grob-property grob 'staff-position)))
278 (if (and (memq 'note-head-interface interfaces)
279 (memq pos '(-2 -3 -5)))
281 (ly:grob-set-property! grob 'print-function brew-new-markup-stencil)
282 (ly:grob-set-property! grob 'font-family 'roman)
283 (ly:grob-set-property!
288 ((-5) (make-simple-markup "m"))
289 ((-3) (make-simple-markup "c "))
290 ((-2) (make-smaller-markup (make-bold-markup "2")))
291 (else (make-simple-markup "bla")))))))))
293 \new Voice \relative c' {
295 \set autoBeaming = ##f
298 \once \override NoteHead #'print-function = #Note_head::brew_ez_stencil
300 \once \override NoteHead #'style = #'cross
302 \applyoutput #mc-squared
305 { d8[ es-( fis^^ g] fis2-) }
306 \repeat unfold 5 { \applyoutput #mc-squared s8 }
313 @node What symbols to engrave?
314 @section What symbols to engrave?
319 The formatting process decides where to place
320 symbols. However, this can only be done once it is decided @emph{what}
321 symbols should be printed, in other words what notation to use.
323 Common music notation is a system of recording music that has evolved
324 over the past 1000 years. The form that is now in common use dates
325 from the early renaissance. Although the basic form (i.e., note heads on a
326 5-line staff) has not changed, the details still change to express the
327 innovations of contemporary notation. Hence, it encompasses some 500
328 years of music. Its applications range from monophonic melodies to
329 monstrous counterpoint for large orchestras.
331 How can we get a grip on such a many-headed beast, and force it into
332 the confines of a computer program? Our solution is break up the
333 problem of notation (as opposed to engraving, i.e., typography) into
334 digestible and programmable chunks: every type of symbol is handled by
335 a separate module, a so-called plug-in. Each plug-in is completely
336 modular and independent, so each can be developed and improved
337 separately. Such plug-ins are called @code{engraver}, by analogy with
338 craftsmen who translate musical ideas to graphic symbols.
340 In the following example, we see how we start out with a plug-in for
341 note heads, the @code{Note_heads_engraver}.
343 @lilypond[quote,raggedright]
344 \include "engraver-example.lyinc"
351 \remove "Stem_engraver"
352 \remove "Phrasing_slur_engraver"
353 \remove "Slur_engraver"
354 \remove "Script_engraver"
355 \remove "Beam_engraver"
356 \remove "Auto_beam_engraver"
360 \remove "Accidental_engraver"
361 \remove "Key_engraver"
362 \remove "Clef_engraver"
363 \remove "Bar_engraver"
364 \remove "Time_signature_engraver"
365 \remove "Staff_symbol_engraver"
366 \consists "Pitch_squash_engraver"
373 Then a @code{Staff_symbol_engraver} adds the staff
375 @lilypond[quote,raggedright]
376 \include "engraver-example.lyinc"
383 \remove "Stem_engraver"
384 \remove "Phrasing_slur_engraver"
385 \remove "Slur_engraver"
386 \remove "Script_engraver"
387 \remove "Beam_engraver"
388 \remove "Auto_beam_engraver"
392 \remove "Accidental_engraver"
393 \remove "Key_engraver"
394 \remove "Clef_engraver"
395 \remove "Bar_engraver"
396 \consists "Pitch_squash_engraver"
397 \remove "Time_signature_engraver"
404 the @code{Clef_engraver} defines a reference point for the staff
406 @lilypond[quote,raggedright]
407 \include "engraver-example.lyinc"
414 \remove "Stem_engraver"
415 \remove "Phrasing_slur_engraver"
416 \remove "Slur_engraver"
417 \remove "Script_engraver"
418 \remove "Beam_engraver"
419 \remove "Auto_beam_engraver"
423 \remove "Accidental_engraver"
424 \remove "Key_engraver"
425 \remove "Bar_engraver"
426 \remove "Time_signature_engraver"
433 and the @code{Stem_engraver} adds stems.
435 @lilypond[quote,raggedright]
436 \include "engraver-example.lyinc"
443 \remove "Phrasing_slur_engraver"
444 \remove "Slur_engraver"
445 \remove "Script_engraver"
446 \remove "Beam_engraver"
447 \remove "Auto_beam_engraver"
451 \remove "Accidental_engraver"
452 \remove "Key_engraver"
453 \remove "Bar_engraver"
454 \remove "Time_signature_engraver"
460 The @code{Stem_engraver} is notified of any note head coming along.
461 Every time one (or more, for a chord) note head is seen, a stem
462 object is created and connected to the note head. By adding
463 engravers for beams, slurs, accents, accidentals, bar lines,
464 time signature, and key signature, we get a complete piece of
467 @lilypond[quote,raggedright]
468 \include "engraver-example.lyinc"
472 This system works well for monophonic music, but what about
473 polyphony? In polyphonic notation, many voices can share a staff.
475 @lilypond[quote,raggedright]
476 \include "engraver-example.lyinc"
477 \new Staff << \topVoice \\ \botVoice >>
480 In this situation, the accidentals and staff are shared, but the
481 stems, slurs, beams, etc., are private to each voice. Hence, engravers
482 should be grouped. The engravers for note heads, stems, slurs, etc., go
483 into a group called `Voice context,' while the engravers for key,
484 accidental, bar, etc., go into a group called `Staff context.' In the
485 case of polyphony, a single Staff context contains more than one Voice
487 Similarly, more Staff contexts can be put into a single Score context.
489 @lilypond[quote,raggedright]
490 \include "engraver-example.lyinc"
493 \new Staff << \topVoice \\ \botVoice >>
494 \new Staff << \pah \\ \hoom >>
499 @node Music representation
500 @section Music representation
502 Ideally, the input format for any high-level formatting system is an
503 abstract description of the content. In this case, that would be the
504 music itself. This poses a formidable problem: how can we define what
505 music really is? Instead of trying to find an answer, we have reversed
506 the question. We write a program capable of producing sheet music,
507 and adjust the format to be as lean as possible. When the format can
508 no longer be trimmed down, by definition we are left with content
509 itself. Our program serves as a formal definition of a music
512 The syntax is also the user-interface for LilyPond, hence it is easy
520 a quarter note C1 (middle C) and an eighth note D1 (D above middle C)
522 @lilypond[quote,fragment]
526 On a microscopic scale, such syntax is easy to use. On a larger
527 scale, syntax also needs structure. How else can you enter complex
528 pieces like symphonies and operas? The structure is formed by the
529 concept of music expressions: by combining small fragments of music
530 into larger ones, more complex music can be expressed. For example
532 @lilypond[quote,verbatim,fragment,relative=1]
537 Chords can be constructed with @code{<<} and @code{>>} enclosing the notes
539 @c < > is not a music expression,
540 @c so we use <<>> iso. <> to drive home the point of
541 @c expressions. Don't change this back --hwn.
546 @lilypond[quote,fragment,relative=1]
547 \new Voice { <<c4 d4 e>> }
551 This expression is put in sequence by enclosing it in curly braces
552 @code{@{@tie{}@dots{}@tie{}@}}
555 @{ f4 <<c4 d4 e4>> @}
558 @lilypond[quote,relative=1,fragment]
563 The above is also an expression, and so it may be combined
564 again with another simultaneous expression (a half note) using <<,
568 << g2 \\ @{ f4 <<c4 d4 e4>> @} >>
571 @lilypond[quote,fragment,relative=2]
572 \new Voice { << g2 \\ { f4 <<c d e>> } >> }
575 Such recursive structures can be specified neatly and formally in a
576 context-free grammar. The parsing code is also generated from this
577 grammar. In other words, the syntax of LilyPond is clearly and
578 unambiguously defined.
580 User-interfaces and syntax are what people see and deal with
581 most. They are partly a matter of taste, and also subject of much
582 discussion. Although discussions on taste do have their merit, they
583 are not very productive. In the larger picture of LilyPond, the
584 importance of input syntax is small: inventing neat syntax is easy, while
585 writing decent formatting code is much harder. This is also
586 illustrated by the line-counts for the respective components: parsing
587 and representation take up less than 10% of the source code.
590 @node Example applications
591 @section Example applications
593 We have written LilyPond as an experiment of how to condense the art
594 of music engraving into a computer program. Thanks to all that hard
595 work, the program can now be used to perform useful tasks. The
596 simplest application is printing notes.
598 @lilypond[quote,relative=1,fragment]
599 \time 2/4 c4 c g'4 g a4 a g2
603 By adding chord names and lyrics we obtain a lead sheet.
605 @lilypond[quote,raggedright]
607 \chords { c2 c f2 c }
608 \new Staff \relative c' { \time 2/4 c4 c g'4 g a4 a g2 }
609 \new Lyrics \lyricmode { twin4 kle twin kle lit tle star2 }
613 Polyphonic notation and piano music can also be printed. The following
614 example combines some more exotic constructs.
616 @lilypondfile[quote,raggedright]{screech-boink.ly}
618 The fragments shown above have all been written by hand, but that is
619 not a requirement. Since the formatting engine is mostly automatic, it
620 can serve as an output means for other programs that manipulate
621 music. For example, it can also be used to convert databases of
622 musical fragments to images for use on websites and multimedia
625 This manual also shows an application: the input format is text, and
626 can therefore be easily embedded in other text-based formats such as
627 La@TeX{}, HTML, or in the case of this manual, Texinfo. By means of a
628 special program, the input fragments can be replaced by music images
629 in the resulting PDF or HTML output files. This makes it easy
630 to mix music and text in documents.
634 @node About this manual
635 @section About this manual
637 The manual is divided into the following chapters:
644 @emph{@ref{Tutorial}}
645 gives a gentle introduction to typesetting music. First time
646 users should start here.
652 @emph{@ref{Example templates}}
653 provides templates of LilyPond pieces. Just cut and paste a
654 template into a file, add notes, and you're done!
660 @emph{@ref{Notation manual}}
661 discusses topics grouped by notation construct. Once you master the
662 basics, this is the place to look up details.
668 @emph{@ref{Changing defaults}}
669 explains how to fine tune layout.
675 @emph{@ref{Running LilyPond}} shows how to run LilyPond and its helper
682 @emph{@ref{Integrating text and music}}
683 explains the details behind creating documents with in-line music
684 examples (like this manual).
690 @emph{@ref{Converting from other formats}}
691 explains how to run the conversion programs. These programs
692 are supplied with the LilyPond package, and convert a variety of music
693 formats to the @code{.ly} format. In addition, this section explains
694 how to upgrade input files from previous versions of LilyPond.
700 @emph{@ref{Literature list}}
701 contains a set of useful reference books for those who wish to know
702 more on notation and engraving.
705 Once you are an experienced user, you can use the manual as reference:
706 there is an extensive index@footnote{If you are looking for something,
707 and you cannot find it in the manual, that is considered a bug. In
708 that case, please file a bug report.}, but the document is also
714 @uref{../lilypond.html, a big HTML page}
716 which can be searched easily using the search facility of a web
718 @cindex search in manual
719 @cindex using the manual
722 @c add/integrate glossary, put in list above
723 If you are not familiar with music notation or music terminology
724 (especially if you are a non-native English speaker), it is advisable
725 to consult the glossary as well. The glossary explains musical terms,
726 and includes translations to various languages. It is a
728 @uref{../music-glossary.html,separate document}.
731 separate document, available in HTML and PDF.
736 @cindex foreign languages
740 This manual is not complete without a number of other documents. They
741 are not available in print, but should be included with the
742 documentation package for your platform:
748 (available @uref{../lilypond-internals/lilypond-internals.html,here})
751 The program reference is a set of heavily cross linked HTML pages,
752 which document the nit-gritty details of each and every LilyPond
753 class, object, and function. It is produced directly from the
754 formatting definitions used.
756 Almost all formatting functionality that is used internally, is
757 available directly to the user. For example, all variables that
758 control thickness values, distances, etc., can be changed in input
759 files. There are a huge number of formatting options, and all of them
760 are described in this document. Each section of the
761 notation manual has a @b{See also} subsection, which refers to the
762 the generated documentation. In the HTML document, these subsections
763 have clickable links.
766 Various input examples
768 (available @uref{../../../../input/test/out-www/collated-files.html,here})
772 This collection of files shows various tips and tricks, and is
773 available as a big HTML document, with pictures and explanatory texts
779 (available @uref{../../../../input/regression/out-www/collated-files.html,here})
782 This collection of files tests each notation and engraving feature of
783 LilyPond in one file. The collection is primarily there to help us
784 debug problems, but it can be instructive to see how we exercise the
785 program. The format is similar to the the tips and tricks document.
789 In all HTML documents that have music fragments embedded, the LilyPond
790 input that was used to produce that image can be viewed by clicking
793 The location of the documentation files that are mentioned here can
794 vary from system to system. On occasion, this manual refers to
795 initialization and example files. Throughout this manual, we refer to
796 input files relative to the top-directory of the source archive. For
797 example, @file{input/test/bla.ly} may refer to the file
798 @file{lilypond-2.3.14/input/test/bla.ly}. On binary packages for the
799 Unix platform, the documentation and examples can typically be found
800 somewhere below @file{/usr/share/doc/lilypond/}. Initialization files,
801 for example @file{scm/lily.scm}, or @file{ly/engraver-init.ly}, are
802 usually found in the directory @file{/usr/share/lilypond/}.
804 @cindex adjusting output
807 @cindex lilypond-internals
808 @cindex internal documentation
810 @cindex extending lilypond
814 Finally, this and all other manuals, are available online both as PDF
815 files and HTML from the web site, which can be found at
816 @uref{http://www.lilypond.org/}.