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. Only a
23 few decades ago, sheet music was made by cutting and stamping the
24 music into zinc or pewter plates in mirror image. The plate would be
25 inked, and the depressions caused by the cutting and stamping would
26 hold ink. An image was formed by pressing paper to the plate. The
27 stamping and cutting was completely done by hand. Making corrections
28 was cumbersome, so engraving had to be done correctly in one go. Of
29 course, this was a highly specialized skill, and a craftsman had to
30 complete around 10 years of practical training before he could be a
34 Nowadays, all newly printed music is produced on computers. This has
35 obvious advantages: prints are cheaper to make, and editorial work can
36 be done over e-mail. Unfortunately, the pervasive use of computers has
37 also decreased the graphical quality of scores. Computer printouts
38 have a bland, mechanical look, which makes them unpleasant to play
41 The images below illustrate the difference between traditional
42 engraving and typical computer output, and the third picture shows how
43 LilyPond mimics the traditional look. The left picture shows a scan
44 of a flat symbol from a Henle edition published in 2000. In the center
45 show symbol from a hand engraved B@"{a}renreiter edition of the same
46 music. The left scan illustrates typical flaws of computer print: the
47 staff line are thin, the weight of the symbol matches the light lines,
48 and the glyph has a straight layout with sharp corners. By contrast,
49 the B@"{a}renreiter has a bold and almost voluptuous rounded look.
50 Our flat symbol is designed after, among others, this one. It is
51 rounded, and its weight harmonizes with the thickness of our staff
52 lines, which are also much thicker than Henle's lines.
54 @multitable @columnfractions .1 .3 .3 .3
58 @image{henle-flat-bw,4cm}
61 @image{henle-flat-bw,,,png}
66 @image{baer-flat-bw,4cm}
69 @image{baer-flat-bw,,,png}
74 @image{lily-flat-bw,4cm}
77 @image{lily-flat-bw,,,png}
81 @c workaround for makeinfo-4.6: line breaks and multi-column cookies
82 @image{henle-flat-bw,,,png} @image{baer-flat-bw,,,png} @image{lily-flat-bw,,,png}
88 B@"{a}renreiter (1950)
90 LilyPond Feta font (2003)
95 @cindex musical symbols
100 In spacing, the distribution of space should reflect the durations
101 between notes. However, many modern scores adhere to the durations
102 with mathematical precision, and that leads to a poor result. In the
103 next example, a motive is printed twice. It is printed using exact
104 mathematical spacing, and with some corrections. Can you spot which
107 @cindex optical spacing
110 \override Staff.NoteSpacing #'stem-spacing-correction
113 \stemDown b'4 e''4 a'4 e''4| \stemBoth
115 \override Staff.NoteSpacing #'stem-spacing-correction
117 \override Staff.StaffSpacing #'stem-spacing-correction
120 \stemDown b'4 e''4 a'4 e''4|
122 \paper { raggedright = ##t } }
125 @cindex regular rhythms
126 @cindex regular spacing
128 The fragment only uses quarter notes: notes that are played in a
129 constant rhythm. The spacing should reflect that. Unfortunately, the
130 eye deceives us a little: not only does it notice the distance between
131 note heads, it also takes into account the distance between
132 consecutive stems. As a result, the notes of an up-stem/down-stem
133 combination should be put farther apart, and the notes of a down-up
134 combination should be put closer together, all depending on the
135 combined vertical positions of the notes. The first two measures are
136 printed with this correction, the last two measures without. The notes
137 in the last two measures form down-stem/up-stem clumps of notes.
141 Musicians are usually more absorbed with performing the music than
142 with studying its looks, so this nitpicking about typographical
143 details may seem academical. That is not justified. In larger pieces
144 with monotonous rhythms, spacing corrections lead to subtle variations
145 in the layout of every line, giving each one a distinct visual
146 signature. Without this signature, all lines would look the same, they
147 become like a labyrinth. If the musician looks away once or has a
148 lapse in his concentration, he will be lost on the page.
150 Similarly, the strong visual look of bold symbols on heavy staff lines
151 stands out better when music is far away from reader, for example, if
152 it is on a music stand. A careful distribution of white space allows
153 music to be set very tightly without cluttering symbols together. The
154 result minimizes the number of page turns,
156 This is a common characteristic of typography. Layout should be
157 pretty, not only for its own sake, but especially because it helps the
158 reader in his task. For performance material like sheet music, this is
159 doubly important: musicians have a limited amount of attention. The
160 less attention they need for reading, the more they can focus on
161 playing itself. In other words, better typography translates to better
164 Hopefully, these examples also demonstrate that music typography is an
165 art that is subtle and complex, and to produce it requires
166 considerable expertise, which musicians usually do not have. LilyPond
167 is our effort to bring the graphical excellence of hand-engraved music
168 to the computer age, and make it available to normal musicians. We
169 have tuned our algorithms, font-designs, and program settings to
170 produce prints that match the quality of the old editions we love to
171 see and love to play from.
176 @node Automated engraving
177 @section Automated engraving
179 How do we go about implementing typography? If craftsmen need over
180 ten years to become true masters, how could we simple hackers ever
181 write a program to take over their jobs?
183 The answer is: we cannot. Typography relies on human judgment of
184 appearance, so people cannot be replaced ultimately. However, much of
185 the dull work can be automated. If LilyPond solves most of the common
186 situations correctly, then this will be a huge improvement over
187 existing software. The remaining cases can be tuned by hand. Over the
188 course of years, the software can be refined to do more and more
189 automatically, so manual overrides are less and less necessary.
191 When we started, we wrote the program in C++. With this design, the
192 program functionality was set in stone stone by us developers. That
193 proved to be unsatisfactory:
197 @item When LilyPond makes mistakes,
198 users need to override formatting decisions. Therefore, the user
199 must access to the formatting engine. Hence, rules and settings cannot
200 be fixed by us at compile time, but they must be accessible for users
203 @item Engraving is a matter of visual judgment, and therefore a matter of
204 taste. As knowledgeable as we are, users can disagree with our
205 personal decisions. Therefore, the definitions of typographical style
206 must also be accessible to the user.
208 @item Finally, we continually refine the formatting algorithms, so we
209 need a flexible approach to rules. The C++ language forces a certain
210 method of grouping rules that do not match well with how music
215 The formatting architecture of LilyPond addresses these needs. It is
216 built around the notion graphical objects, carrying variables. The
217 architecture encompasses formatting rules, typographical style and
218 individual formatting decisions.
220 Variables control layout decisions. For example, many objects have a
221 direction variable that encodes the choice between up and down (or
222 left and right). Here you see two chords, with accents and
223 arpeggio. In the first chord, the objects have all directions down (or
224 left). The second chord has all directions up (right).
226 @lilypond[raggedright,relative=1]
228 \override SpacingSpanner #'spacing-increment = #3
229 \override TimeSignature #'transparent = ##t
234 \override Arpeggio #'direction = #RIGHT
240 The process of formatting a score consists of reading and
241 writing object variables.
243 Some variables have a preset value. For example, the thickness of many
244 lines ---a characteristic of typographical style--are preset
245 variables. Changing them gives a different typographical impression:
250 c'4-~ c'16 as g f e16 g bes c' des'4
252 \paper { raggedright = ##t }
257 \override Beam #'thickness = #0.3
258 \override Stem #'thickness = #0.5
259 \override Bar #'thickness = #3.6
260 \override Tie #'thickness = #2.2
261 \override StaffSymbol #'thickness = #3.0
262 \override Tie #'extra-offset = #'(0 . 0.3)
268 Formatting rules are also preset variables: each object has variables
269 containing procedures. These procedure perform the actual formatting,
270 and by substituting different ones, we can change behavior. In the
271 following example, the rule that note head objects use to produce
272 their symbol is changed during the music fragment:
275 @lilypond[raggedright]
276 #(define (mc-squared gr org cur)
278 ((ifs (ly:grob-property gr 'interfaces))
279 (sp (ly:grob-property gr 'staff-position)) )
280 (if (and (memq 'note-head-interface ifs)
281 (memq sp '(-2 -3 -5)))
283 (ly:grob-set-property! gr 'print-function brew-new-markup-stencil)
284 (ly:grob-set-property! gr 'font-family 'roman)
285 (ly:grob-set-property!
287 (make-raise-markup -0.5
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"))
297 \notes \context Voice \relative c'
300 \set autoBeaming = ##f
303 \once \override NoteHead #'print-function
304 = #Note_head::brew_ez_stencil
306 \once \override NoteHead #'style
309 \applyoutput #mc-squared
311 << { d8[ es-( fis^^ g] fis2-) }
312 \repeat unfold 5 { \applyoutput #mc-squared s8 } >>
322 @node What symbols to engrave?
323 @section What symbols to engrave?
328 The formatting process in LilyPond decides where to place
329 symbols. However, this can only be done once it is decided @emph{what}
330 symbols should be printed, in other words what notation to use.
332 Common music notation is a system of recording music that has evolved
333 over the past 1000 years. The form that is now in common use, dates
334 from the early renaissance. Although, the basic form (i.e. note heads on a
335 5-line staff) has not changed, the details still change to express the
336 innovations of contemporary notation. Hence, it encompasses some 500
337 years of music. Its applications range from monophonic melodies to
338 monstrous counterpoint for large orchestras.
340 How can we get a grip on such a many-headed beast, and force it into
341 the confines of a computer program? We have broken up the problem of
342 notation (as opposed to engraving, i.e. typography) into digestible
343 and programmable chunks: every type of symbol is handled by a separate
344 module, a so-called plug-in. Each plug-in is completely modular and
345 independent, so each can be developed and improved separately. People
346 that translate musical ideas to graphic symbols are called copyists or
347 engravers, so by analogy, each plug-in is called @code{engraver}.
349 In the following example, we see how we start out with a plug-in for
350 note heads, the @code{Note_heads_engraver}.
353 \include "engraver-example.lyinc"
357 \context { \VoiceContext
358 \remove "Stem_engraver"
359 \remove "Phrasing_slur_engraver"
360 \remove "Slur_engraver"
361 \remove "Script_engraver"
362 \remove "Beam_engraver"
363 \remove "Auto_beam_engraver"
366 \context { \StaffContext
367 \remove "Accidental_engraver"
368 \remove "Key_engraver"
369 \remove "Clef_engraver"
370 \remove "Bar_engraver"
371 \remove "Time_signature_engraver"
372 \remove "Staff_symbol_engraver"
373 \consists "Pitch_squash_engraver"
380 Then a @code{Staff_symbol_engraver} adds the staff:
383 \include "engraver-example.lyinc"
387 \context { \VoiceContext
388 \remove "Stem_engraver"
389 \remove "Phrasing_slur_engraver"
390 \remove "Slur_engraver"
391 \remove "Script_engraver"
392 \remove "Beam_engraver"
393 \remove "Auto_beam_engraver"
396 \context { \StaffContext
397 \remove "Accidental_engraver"
398 \remove "Key_engraver"
399 \remove "Clef_engraver"
400 \remove "Bar_engraver"
401 \consists "Pitch_squash_engraver"
402 \remove "Time_signature_engraver"
409 The @code{Clef_engraver} defines a reference point for the staff:
412 \include "engraver-example.lyinc"
416 \context { \VoiceContext
417 \remove "Stem_engraver"
418 \remove "Phrasing_slur_engraver"
419 \remove "Slur_engraver"
420 \remove "Script_engraver"
421 \remove "Beam_engraver"
422 \remove "Auto_beam_engraver"
424 \context { \StaffContext
425 \remove "Accidental_engraver"
426 \remove "Key_engraver"
427 \remove "Bar_engraver"
428 \remove "Time_signature_engraver"
435 And the @code{Stem_engraver} adds stems:
438 \include "engraver-example.lyinc"
442 \context { \VoiceContext
443 \remove "Phrasing_slur_engraver"
444 \remove "Slur_engraver"
445 \remove "Script_engraver"
446 \remove "Beam_engraver"
447 \remove "Auto_beam_engraver"
449 \context { \StaffContext
450 \remove "Accidental_engraver"
451 \remove "Key_engraver"
452 \remove "Bar_engraver"
453 \remove "Time_signature_engraver"
459 The @code{Stem_engraver} is notified of any note head coming along.
460 Every time one (or more, for a chord) note head is seen, a stem
461 object is created and connected to the note head.
463 By adding engravers for beams, slurs, accents, accidentals, bar lines,
464 time signature, and key signature, we get a complete piece of
468 \include "engraver-example.lyinc"
475 This system works well for monophonic music, but what about
476 polyphony? In polyphonic notation, many voices can share a staff.
479 \include "engraver-example.lyinc"
480 \score { \context Staff << \topVoice \\ \botVoice >> }
483 In this situation, the accidentals and staff are shared, but the
484 stems, slurs, beams, etc. are private to each voice. Hence, engravers
485 should be grouped. The engravers for note heads, stems, slurs, etc. go
486 into a group called ``Voice context,'' while the engravers for key,
487 accidental, bar, etc. go into a group called ``Staff context.'' In the
488 case of polyphony, a single Staff context contains more than one Voice
489 context. In polyphonic notation, many voices can share a staff:
490 Similarly, more Staff contexts can be put into a single Score context.
493 \include "engraver-example.lyinc"
495 << \new Staff << \topVoice \\ \botVoice >>
496 \new Staff << \pah \\ \hoom >>
501 @node Music representation
502 @section Music representation
504 Ideally, the input format for any high-level formatting system is an
505 abstract description of the content. In this case, that would be the
506 music itself. This poses a formidable problem: how can we define what
507 music really is? Instead of trying to find an answer, we have reversed
508 the question. We write a program capable of producing sheet music,
509 and adjust the format to be as lean as possible. When the format can
510 no longer be trimmed down, by definition we are left with content
511 itself. Our program serves as a formal definition of a music
515 The syntax is also the user-interface for LilyPond, hence it is easily typable, e.g.,
519 Are a quarter note C (middle C) and eighth note D1 (D above middle C),
526 On a microscopic scale, such syntax is easy to use. On a larger scale,
527 syntax also needs structure. How else can you enter complex pieces
528 like symphonies and operas? The structure is formed by the concept of
529 music expressions: by combining small fragments of music into larger
530 ones, more complex music can be expressed. For example,
532 @lilypond[verbatim,fragment,relative=1]
536 Combine this simultaneously with two other notes by enclosing in << and >>.
539 @lilypond[verbatim,fragment,relative=1]
545 This expression is put in sequence by enclosing it in braces, i.e.,
551 @lilypond[relative=1]
552 \new Voice { <<c4 d4 e4>> f4 }
555 The above is another expression, and therefore, it many combined again
556 with a simultaneous expression (in this case, a half note).
559 << { <<c4 d4 e4>> f4 } g2 >>
561 @lilypond[fragment,relative=1]
562 << g2 \\ { <c d e>4 f4 } >>
566 Such recursive structures can be specified neatly and formally in a
567 context-free grammar. The parsing code is also generated from this
568 grammar. In other words, the syntax of LilyPond is clearly and
569 unambiguously defined.
571 User-interfaces and syntax are what people see and deal with
572 most. They are partly a matter of taste, and also subject of much
573 discussion. Although discussions on taste do have their merit, they
574 are not very productive. In the larger picture of LilyPond, the
575 importance of input syntax is small: inventing neat syntax is easy,
576 writing decent formatting code is much harder. This is also
577 illustrated by the line-counts for the respective components: parsing
578 and representation take up less than 10% of the code.
581 @node Example applications
582 @section Example applications
584 We have written LilyPond as an experiment of how to condense the art
585 of music engraving into a computer program. Thanks to all that hard
586 work, the program can now be used to perform useful tasks. The
587 simplest application is printing notes:
589 @lilypond[relative=1]
590 \time 2/4 c4 c g'4 g a4 a g2
593 By adding chord names and lyrics we obtain a lead sheet:
595 @lilypond[raggedright]
597 \context ChordNames \chords { c2 c f2 c }
598 \new Staff \notes \relative c' { \time 2/4 c4 c g'4 g a4 a g2 }
599 \context Lyrics \lyrics { twin4 kle twin kle lit tle star2 } >> }
602 Polyphonic notation and piano music can also be printed. The following
603 example combines some more exotic constructs:
605 @lilypondfile{screech-boink.ly}
607 The fragments shown above have all been written by hand, but that is
608 not a requirement. Since the formatting engine is mostly automatic, it
609 can serve as an output means for other programs that manipulate
610 music. For example, it can also be used to convert databases of
611 musical fragments to images for use on websites and multimedia
614 This manual also shows an application: the input format is plain text,
615 and can therefore be easily embedded in other text-based formats, such
616 as La@TeX{}, HTML or in the case of this manual, Texinfo. By means of a
617 special program, the input fragments can be replaced by music images in
618 the resulting PostScript or HTML output files. This makes it easy to
619 mix music and text in documents.
623 @node About this manual
624 @section About this manual
626 The manual is divided into the following chapters:
631 @emph{@ref{Tutorial}}
632 gives a gentle introduction to typesetting music.
633 First time users should start here.
638 @emph{@ref{Notation manual}}
639 discusses topics grouped by notation construct. Once you master the
640 basics, this is the place to look up details.
645 @emph{@ref{Literature list}}
646 contains a set of useful reference books, for those who wish to know
647 more on notation and engraving.
652 @emph{@ref{Changing defaults}}
654 Explains how to fine tune layout.
659 @emph{@ref{Invoking LilyPond}} explains how to run LilyPond and its helper
666 @emph{@ref{lilypond-book manual}}
667 explains the details behind creating documents with in-line music
668 examples (like this manual).
675 @emph{@ref{Converting from other formats}}
676 explains how to run the conversion programs. These programs
677 are supplied with the LilyPond package, and convert a variety of music
678 formats to the @code{.ly} format. In addition, this section explains
679 how to upgrade input files from previous versions of LilyPond.
683 Once you are an experienced user, you can use the manual as reference:
684 there is an extensive index@footnote{If you are looking for something,
685 and you cannot find it in the manual, that is considered a bug. In
686 that case, please file a bug report.}, but the document is also
692 @uref{../lilypond.html, a big HTML page}
694 which can be searched easily using the search facility of a web
696 @cindex search in manual
697 @cindex using the manual
700 If you are not familiar with music notation or music terminology
701 (especially if you are a non-native English speaker), then it is
702 advisable to consult the glossary as well. The glossary explains
703 musical terms, and includes translations to various languages. It is a
705 @uref{../music-glossary.html,separate document}.
708 separate document, available in HTML and PDF.
713 @cindex foreign languages
717 This manual is not complete without a number of other documents. They
718 are not available in print, but should be included with the
719 documentation package for your platform:
725 (available @uref{../lilypond-internals/lilypond-internals.html,here})
728 The program reference is a set of heavily cross linked HTML pages,
729 which documents the nit-gritty details of each and every LilyPond
730 class, object and function. It is produced directly from the
731 formatting definitions used.
733 Almost all formatting functionality that is used internally, is
734 available directly to the user. For example, all variables that
735 control thicknesses, distances, etc, can be changed in input
736 files. There are a huge number of formatting options, and all of them
737 are described in the generated documentation. Each section of the
738 notation manual has a @b{See also} subsection, which refers to the
739 the generated documentation. In the HTML document, these subsections
740 have clickable links.
745 (available @uref{../../../input/template/out-www/collated-files.html,here})
748 After you have gone through the tutorial, you should be able to write
749 input files. In practice, writing files from scratch turns out to be
750 intimidating. To give you a head start, we have collected a number of
751 often-used formats in example files. These files can be used as a
752 start: simply copy the template, and add notes in the appropriate
756 Various input examples
758 (available @uref{../../../../input/test/out-www/collated-files.html,here})
762 These small files show various tips and tricks, and are available as a
763 big HTML document, with pictures and explanatory texts included.
769 (available @uref{../../../input/regression/out-www/collated-files.html,here})
772 This collection of files tests each notation and engraving feature of
773 LilyPond in one file. The collection is primarily there to help us
774 debug problems, but it can be instructive to see how we exercise the
775 program. The format is like the tips and tricks document.
780 In all HTML documents that have music fragments embedded, the LilyPond
781 input that was used to produce that image can be viewed by clicking
784 The location of the documentation files that are mentioned here can
785 vary from system to system. On occasion, this manual refers to
786 initialization and example files. Throughout this manual, we refer to
787 input files relative to the top-directory of the source archive. For
788 example, @file{input/test/bla.ly} may refer to the file
789 @file{lilypond-1.7.19/input/test/bla.ly}. On binary packages for the
790 Unix platform, the documentation and examples can typically be found
791 somewhere below @file{/usr/share/doc/lilypond/}. Initialization files,
792 for example @file{scm/lily.scm}, or @file{ly/engraver-init.ly}, are
793 usually found in the directory @file{/usr/share/lilypond/}.
795 @cindex adjusting output
798 @cindex lilypond-internals
799 @cindex internal documentation
801 @cindex extending lilypond
805 Finally, this and all other manuals, are available online both as PDF
806 files and HTML from the web site, which can be found at
807 @uref{http://www.lilypond.org/}.