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 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 \stemNeutral 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-stem/@/up-stem
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 a 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, the lines 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 the music is far away from the reader, for example,
150 if 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 the music. 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 things
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 arpeggios. 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]
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 are used 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 evolve 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 counterpoints 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 to 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}s, 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.ily"
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.ily"
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.ily"
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.ily"
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.ily"
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.ily"
477 \new Staff << \topVoice \\ \botVoice >>
480 In this situation, the accidentals and staff are shared, but the stems,
481 slurs, beams, etc., are private to each voice. Hence, engravers should
482 be grouped. The engravers for note heads, stems, slurs, etc., go into a
483 group called `Voice context,' while the engravers for key, accidental,
484 bar, etc., go into a group called `Staff context.' In the case of
485 polyphony, a single Staff context contains more than one Voice context.
486 Similarly, multiple Staff contexts can be put into a single Score
487 context. The Score context is the top level notation context.
491 Program reference: @internalsref{Contexts}.
493 @lilypond[quote,raggedright]
494 \include "engraver-example.ily"
497 \new Staff << \topVoice \\ \botVoice >>
498 \new Staff << \pah \\ \hoom >>
503 @node Music representation
504 @section Music representation
506 Ideally, the input format for any high-level formatting system is an
507 abstract description of the content. In this case, that would be the
508 music itself. This poses a formidable problem: how can we define what
509 music really is? Instead of trying to find an answer, we have reversed
510 the question. We write a program capable of producing sheet music,
511 and adjust the format to be as lean as possible. When the format can
512 no longer be trimmed down, by definition we are left with content
513 itself. Our program serves as a formal definition of a music
516 The syntax is also the user-interface for LilyPond, hence it is easy
524 a quarter note C1 (middle C) and an eighth note D1 (D above middle C)
526 @lilypond[quote,fragment]
530 On a microscopic scale, such syntax is easy to use. On a larger
531 scale, syntax also needs structure. How else can you enter complex
532 pieces like symphonies and operas? The structure is formed by the
533 concept of music expressions: by combining small fragments of music
534 into larger ones, more complex music can be expressed. For example
536 @lilypond[quote,verbatim,fragment,relative=1]
541 Chords can be constructed with @code{<<} and @code{>>} enclosing the notes
543 @c < > is not a music expression,
544 @c so we use <<>> iso. <> to drive home the point of
545 @c expressions. Don't change this back --hwn.
550 @lilypond[quote,fragment,relative=1]
551 \new Voice { <<c4 d4 e>> }
555 This expression is put in sequence by enclosing it in curly braces
556 @code{@{@tie{}@dots{}@tie{}@}}
559 @{ f4 <<c4 d4 e4>> @}
562 @lilypond[quote,relative=1,fragment]
567 The above is also an expression, and so it may be combined
568 again with another simultaneous expression (a half note) using <<,
572 << g2 \\ @{ f4 <<c4 d4 e4>> @} >>
575 @lilypond[quote,fragment,relative=2]
576 \new Voice { << g2 \\ { f4 <<c d e>> } >> }
579 Such recursive structures can be specified neatly and formally in a
580 context-free grammar. The parsing code is also generated from this
581 grammar. In other words, the syntax of LilyPond is clearly and
582 unambiguously defined.
584 User-interfaces and syntax are what people see and deal with
585 most. They are partly a matter of taste, and also subject of much
586 discussion. Although discussions on taste do have their merit, they
587 are not very productive. In the larger picture of LilyPond, the
588 importance of input syntax is small: inventing neat syntax is easy, while
589 writing decent formatting code is much harder. This is also
590 illustrated by the line-counts for the respective components: parsing
591 and representation take up less than 10% of the source code.
594 @node Example applications
595 @section Example applications
597 We have written LilyPond as an experiment of how to condense the art
598 of music engraving into a computer program. Thanks to all that hard
599 work, the program can now be used to perform useful tasks. The
600 simplest application is printing notes.
602 @lilypond[quote,relative=1,fragment]
603 \time 2/4 c4 c g'4 g a4 a g2
607 By adding chord names and lyrics we obtain a lead sheet.
609 @lilypond[quote,raggedright]
611 \chords { c2 c f2 c }
612 \new Staff \relative c' { \time 2/4 c4 c g'4 g a4 a g2 }
613 \new Lyrics \lyricmode { twin4 kle twin kle lit tle star2 }
617 Polyphonic notation and piano music can also be printed. The following
618 example combines some more exotic constructs.
620 @lilypondfile[quote,raggedright]{screech-boink.ly}
622 The fragments shown above have all been written by hand, but that is
623 not a requirement. Since the formatting engine is mostly automatic, it
624 can serve as an output means for other programs that manipulate
625 music. For example, it can also be used to convert databases of
626 musical fragments to images for use on websites and multimedia
629 This manual also shows an application: the input format is text, and
630 can therefore be easily embedded in other text-based formats such as
631 La@TeX{}, HTML, or in the case of this manual, Texinfo. By means of a
632 special program, the input fragments can be replaced by music images
633 in the resulting PDF or HTML output files. This makes it easy
634 to mix music and text in documents.
638 @node About this manual
639 @section About this manual
641 The manual is divided into the following chapters:
648 @emph{@ref{Tutorial}}
649 gives a gentle introduction to typesetting music. First time
650 users should start here.
656 @emph{@ref{Example templates}}
657 provides templates of LilyPond pieces. Just cut and paste a
658 template into a file, add notes, and you're done!
664 @emph{@ref{Notation manual}}
665 discusses topics grouped by notation construct. Once you master the
666 basics, this is the place to look up details.
672 @emph{@ref{Changing defaults}}
673 explains how to fine tune layout.
679 @emph{@ref{Running LilyPond}} shows how to run LilyPond and its helper
686 @emph{@ref{LilyPond-book}} explains the details behind creating
687 documents with in-line music examples (like this manual).
693 @emph{@ref{Converting from other formats}}
694 explains how to run the conversion programs. These programs
695 are supplied with the LilyPond package, and convert a variety of music
696 formats to the @code{.ly} format. In addition, this section explains
697 how to upgrade input files from previous versions of LilyPond.
703 @emph{@ref{Literature list}}
704 contains a set of useful reference books for those who wish to know
705 more on notation and engraving.
708 Once you are an experienced user, you can use the manual as reference:
709 there is an extensive index@footnote{If you are looking for something,
710 and you cannot find it in the manual, that is considered a bug. In
711 that case, please file a bug report.}, but the document is also
717 @uref{../lilypond.html, a big HTML page}
719 which can be searched easily using the search facility of a web
721 @cindex search in manual
722 @cindex using the manual
725 @c add/integrate glossary, put in list above
726 If you are not familiar with music notation or music terminology
727 (especially if you are a non-native English speaker), it is advisable
728 to consult the glossary as well. The glossary explains musical terms,
729 and includes translations to various languages. It is a
731 @uref{../music-glossary.html,separate document}.
734 separate document, available in HTML and PDF.
739 @cindex foreign languages
743 This manual is not complete without a number of other documents. They
744 are not available in print, but should be included with the
745 documentation package for your platform:
751 (available @uref{../lilypond-internals/lilypond-internals.html,here})
754 The program reference is a set of heavily cross linked HTML pages,
755 which document the nitty-gritty details of each and every LilyPond
756 class, object, and function. It is produced directly from the
757 formatting definitions used.
759 Almost all formatting functionality that is used internally, is
760 available directly to the user. For example, all variables that
761 control thickness values, distances, etc., can be changed in input
762 files. There are a huge number of formatting options, and all of them
763 are described in this document. Each section of the
764 notation manual has a @b{See also} subsection, which refers to the
765 generated documentation. In the HTML document, these subsections
766 have clickable links.
769 Various input examples
771 (available @uref{../../../../input/test/out-www/collated-files.html,here})
775 This collection of files shows various tips and tricks, and is
776 available as a big HTML document, with pictures and explanatory texts
782 (available @uref{../../../../input/regression/out-www/collated-files.html,here})
785 This collection of files tests each notation and engraving feature of
786 LilyPond in one file. The collection is primarily there to help us
787 debug problems, but it can be instructive to see how we exercise the
788 program. The format is similar to the tips and tricks document.
792 In all HTML documents that have music fragments embedded, the LilyPond
793 input that was used to produce that image can be viewed by clicking
796 The location of the documentation files that are mentioned here can
797 vary from system to system. On occasion, this manual refers to
798 initialization and example files. Throughout this manual, we refer to
799 input files relative to the top-directory of the source archive. For
800 example, @file{input/@/test/@/bla@/.ly} may refer to the file
801 @file{lilypond@/-2.4.0/@/input/@/test/@/bla@/.ly}. On binary packages
802 for the Unix platform, the documentation and examples can typically be
803 found somewhere below @file{/usr/@/share/@/doc/@/lilypond/}.
804 Initialization files, for example @file{scm/@/lily@/.scm}, or
805 @file{ly/@/engraver@/-init@/.ly}, are usually found in the directory
806 @file{/usr/@/share/@/lilypond/}.
808 @cindex adjusting output
811 @cindex lilypond-internals
812 @cindex internal documentation
814 @cindex extending lilypond
818 Finally, this and all other manuals, are available online both as PDF
819 files and HTML from the web site, which can be found at
820 @uref{http://@/www@/.lilypond@/.org/}.