@c -*- coding: utf-8; mode: texinfo; -*- @c This file is part of lilypond.tely @node Introduction @chapter Introduction @menu * Engraving:: * Automated engraving:: * What symbols to engrave?:: * Music representation:: * Example applications:: * About this manual:: @end menu @node Engraving @section Engraving The art of music typography is called @emph{(plate) engraving}. The term derives from the traditional process of music printing. Just a few decades ago, sheet music was made by cutting and stamping the music into a zinc or pewter plate in mirror image. The plate would be inked, the depressions caused by the cutting and stamping would hold ink. An image was formed by pressing paper to the plate. The stamping and cutting was completely done by hand. Making a correction was cumbersome, if possible at all, so the engraving had to be perfect in one go. Engraving was a highly specialized skill; a craftsman had to complete around five years of training before earning the title of master engraver, and another five years of experience were necessary to become truly skilled. Nowadays, all newly printed music is produced with computers. This has obvious advantages; prints are cheaper to make, and editorial work can be delivered by email. Unfortunately, the pervasive use of computers has also decreased the graphical quality of scores. Computer printouts have a bland, mechanical look, which makes them unpleasant to play from. @c introduce illustrating aspects of engraving, font... The images below illustrate the difference between traditional engraving and typical computer output, and the third picture shows how LilyPond mimics the traditional look. The left picture shows a scan of a flat symbol from an edition published in 2000. The center depicts a symbol from a hand-engraved B@"{a}renreiter edition of the same music. The left scan illustrates typical flaws of computer print: the staff lines are thin, the weight of the flat symbol matches the light lines and it has a straight layout with sharp corners. By contrast, the B@"{a}renreiter flat has a bold, almost voluptuous rounded look. Our flat symbol is designed after, among others, this one. It is rounded, and its weight harmonizes with the thickness of our staff lines, which are also much thicker than lines in the computer edition. @multitable @columnfractions .125 .25 .25 .25 .125 @item @tab @ifnotinfo @iftex @image{henle-flat-gray,,4cm} @end iftex @ifnottex @image{henle-flat-gray,,,png} @end ifnottex @tab @iftex @image{baer-flat-gray,,4cm} @end iftex @ifnottex @image{baer-flat-gray,,,png} @end ifnottex @tab @iftex @image{lily-flat-bw,,4cm} @end iftex @ifnottex @image{lily-flat-bw,,,png} @end ifnottex @end ifnotinfo @ifinfo @c workaround for makeinfo-4.6: line breaks and multi-column cookies @image{henle-flat-bw,,,png} @image{baer-flat-bw,,,png} @image{lily-flat-bw,,,png} @end ifinfo @item @tab Henle (2000) @tab B@"{a}renreiter (1950) @tab LilyPond Feta font (2003) @end multitable @cindex musical symbols @cindex font @cindex blackness @cindex balance @c introduce illustrating aspects of engraving, spacing... In spacing, the distribution of space should reflect the durations between notes. However, many modern scores adhere to the durations with mathematical precision, which leads to poor results. In the next example a motive is printed twice. It is printed once using exact mathematical spacing, and once with corrections. Can you spot which fragment is which? @cindex optical spacing @c file spacing-optical. @c need to include it here, because we want two images. @lilypond \paper { ragged-right = ##t indent = #0.0 } music = { c'4 e''4 e'4 b'4 | \stemDown b'8[ e'' a' e''] \stemNeutral e'8[ e'8 e'8 e'8] } \score { \music \layout { \context { \Staff \override NoteSpacing #'stem-spacing-correction = #0.6 } } } @end lilypond @lilypond \paper { ragged-right = ##t indent = #0.0 } music = { c'4 e''4 e'4 b'4 | \stemDown b'8[ e'' a' e''] \stemNeutral e'8[ e'8 e'8 e'8] } \score { \music \layout { \context { \Staff \override NoteSpacing #'stem-spacing-correction = #0.0 \override NoteSpacing #'same-direction-correction = #0.0 \override StaffSpacing #'stem-spacing-correction = #0.0 } } } @end lilypond @cindex regular rhythms @cindex regular spacing Each bar in the fragment only uses notes that are played in a constant rhythm. The spacing should reflect that. Unfortunately, the eye deceives us a little; not only does it notice the distance between note heads, it also takes into account the distance between consecutive stems. As a result, the notes of an up-stem/@/down-stem combination should be put farther apart, and the notes of a down-stem/@/up-stem combination should be put closer together, all depending on the combined vertical positions of the notes. The upper two measures are printed with this correction, the lower two measures without, forming down-stem/@/up-stem clumps of notes. @cindex typography Musicians are usually more absorbed with performing than with studying the looks of a piece of music, so nitpicking about typographical details may seem academical. But it is not. In larger pieces with monotonous rhythms, spacing corrections lead to subtle variations in the layout of every line, giving each one a distinct visual signature. Without this signature all lines would look the same, and they become like a labyrinth. If a musician looks away once or has a lapse in concentration, the lines might lose their place on the page. Similarly, the strong visual look of bold symbols on heavy staff lines stands out better when the music is far away from the reader, for example, if it is on a music stand. A careful distribution of white space allows music to be set very tightly without cluttering symbols together. The result minimizes the number of page turns, which is a great advantage. This is a common characteristic of typography. Layout should be pretty, not only for its own sake, but especially because it helps the reader in her task. For performance material like sheet music, this is of double importance: musicians have a limited amount of attention. The less attention they need for reading, the more they can focus on playing the music. In other words, better typography translates to better performances. These examples demonstrate that music typography is an art that is subtle and complex, and that producing it requires considerable expertise, which musicians usually do not have. LilyPond is our effort to bring the graphical excellence of hand-engraved music to the computer age, and make it available to normal musicians. We have tuned our algorithms, font-designs, and program settings to produce prints that match the quality of the old editions we love to see and love to play from. @node Automated engraving @section Automated engraving How do we go about implementing typography? If craftsmen need over ten years to become true masters, how could we simple hackers ever write a program to take over their jobs? The answer is: we cannot. Typography relies on human judgment of appearance, so people cannot be replaced completely. However, much of the dull work can be automated. If LilyPond solves most of the common situations correctly, this will be a huge improvement over existing software. The remaining cases can be tuned by hand. Over the course of years, the software can be refined to do more and more things automatically, so manual overrides are less and less necessary. When we started, we wrote the LilyPond program entirely in the C++ programming language; the program's functionality was set in stone by the developers. That proved to be unsatisfactory for a number of reasons: @itemize @bullet @item When LilyPond makes mistakes, users need to override formatting decisions. Therefore, the user must have access to the formatting engine. Hence, rules and settings cannot be fixed by us at compile-time but must be accessible for users at run-time. @item Engraving is a matter of visual judgment, and therefore a matter of taste. As knowledgeable as we are, users can disagree with our personal decisions. Therefore, the definitions of typographical style must also be accessible to the user. @item Finally, we continually refine the formatting algorithms, so we need a flexible approach to rules. The C++ language forces a certain method of grouping rules that do not match well with how music notation works. @end itemize These problems have been addressed by integrating an interpreter for the Scheme programming language and rewriting parts of LilyPond in Scheme. The current formatting architecture is built around the notion of graphical objects, described by Scheme variables and functions. This architecture encompasses formatting rules, typographical style and individual formatting decisions. The user has direct access to most of these controls. Scheme variables control layout decisions. For example, many graphical objects have a direction variable that encodes the choice between up and down (or left and right). Here you see two chords, with accents and arpeggios. In the first chord, the graphical objects have all directions down (or left). The second chord has all directions up (right). @lilypond[quote,ragged-right] \new Score \with { \override SpacingSpanner #'spacing-increment = #3 \override TimeSignature #'transparent = ##t } \relative { \stemDown 4_>-\arpeggio \override Arpeggio #'direction = #RIGHT \stemUp 4^>-\arpeggio } @end lilypond @noindent The process of formatting a score consists of reading and writing the variables of graphical objects. Some variables have a preset value. For example, the thickness of many lines -- a characteristic of typographical style -- is a variable with a preset value. You are free to alter this value, giving your score a different typographical impression. @lilypond[quote,ragged-right] fragment = { \clef bass f8 as8 c'4-~ c'16 as g f e16 g bes c' des'4 } << \new Staff \fragment \new Staff \with { \override Beam #'thickness = #0.3 \override Stem #'thickness = #0.5 \override Bar #'thickness = #3.6 \override Tie #'thickness = #2.2 \override StaffSymbol #'thickness = #3.0 \override Tie #'extra-offset = #'(0 . 0.3) } \fragment >> @end lilypond Formatting rules are also preset variables: each object has variables containing procedures. These procedures perform the actual formatting, and by substituting different ones, we can change the appearance of objects. In the following example, the rule which note head objects are used to produce their symbol is changed during the music fragment. @lilypond[quote,ragged-right] #(set-global-staff-size 30) #(define (mc-squared grob orig current) (let* ((interfaces (ly:grob-interfaces grob)) (pos (ly:grob-property grob 'staff-position))) (if (memq 'note-head-interface interfaces) (begin (ly:grob-set-property! grob 'stencil ly:text-interface::print) (ly:grob-set-property! grob 'font-family 'roman) (ly:grob-set-property! grob 'text (make-raise-markup -0.5 (case pos ((-5) (make-simple-markup "m")) ((-3) (make-simple-markup "c ")) ((-2) (make-smaller-markup (make-bold-markup "2"))) (else (make-simple-markup "bla"))))))))) \new Voice \relative c' { \stemUp \set autoBeaming = ##f \time 2/4 4 \once \override NoteHead #'stencil = #ly:note-head::brew-ez-stencil \once \override NoteHead #'font-size = #-7 \once \override NoteHead #'font-family = #'sans \once \override NoteHead #'font-series = #'bold \once \override NoteHead #'style = #'cross \applyOutput #'Voice #mc-squared << { d8[ es-( fis^^ g] fis2-) } \repeat unfold 5 { \applyOutput #'Voice #mc-squared s8 } >> } @end lilypond @node What symbols to engrave? @section What symbols to engrave? @cindex engraving @cindex typography The formatting process decides where to place symbols. However, this can only be done once it is decided @emph{what} symbols should be printed, in other words what notation to use. Common music notation is a system of recording music that has evolved over the past 1000 years. The form that is now in common use dates from the early renaissance. Although the basic form (i.e., note heads on a 5-line staff) has not changed, the details still evolve to express the innovations of contemporary notation. Hence, it encompasses some 500 years of music. Its applications range from monophonic melodies to monstrous counterpoints for large orchestras. How can we get a grip on such a many-headed beast, and force it into the confines of a computer program? Our solution is to break up the problem of notation (as opposed to engraving, i.e., typography) into digestible and programmable chunks: every type of symbol is handled by a separate module, a so-called plug-in. Each plug-in is completely modular and independent, so each can be developed and improved separately. Such plug-ins are called @code{engraver}s, by analogy with craftsmen who translate musical ideas to graphic symbols. In the following example, we see how we start out with a plug-in for note heads, the @code{Note_heads_engraver}. @lilypond[quote,ragged-right] \include "engraver-example.ily" \score { \topVoice \layout { \context { \Voice \remove "Stem_engraver" \remove "Phrasing_slur_engraver" \remove "Slur_engraver" \remove "Script_engraver" \remove "Beam_engraver" \remove "Auto_beam_engraver" } \context { \Staff \remove "Accidental_engraver" \remove "Key_engraver" \remove "Clef_engraver" \remove "Bar_engraver" \remove "Time_signature_engraver" \remove "Staff_symbol_engraver" \consists "Pitch_squash_engraver" } } } @end lilypond @noindent Then a @code{Staff_symbol_engraver} adds the staff @lilypond[quote,ragged-right] \include "engraver-example.ily" \score { \topVoice \layout { \context { \Voice \remove "Stem_engraver" \remove "Phrasing_slur_engraver" \remove "Slur_engraver" \remove "Script_engraver" \remove "Beam_engraver" \remove "Auto_beam_engraver" } \context { \Staff \remove "Accidental_engraver" \remove "Key_engraver" \remove "Clef_engraver" \remove "Bar_engraver" \consists "Pitch_squash_engraver" \remove "Time_signature_engraver" } } } @end lilypond @noindent the @code{Clef_engraver} defines a reference point for the staff @lilypond[quote,ragged-right] \include "engraver-example.ily" \score { \topVoice \layout { \context { \Voice \remove "Stem_engraver" \remove "Phrasing_slur_engraver" \remove "Slur_engraver" \remove "Script_engraver" \remove "Beam_engraver" \remove "Auto_beam_engraver" } \context { \Staff \remove "Accidental_engraver" \remove "Key_engraver" \remove "Bar_engraver" \remove "Time_signature_engraver" } } } @end lilypond @noindent and the @code{Stem_engraver} adds stems. @lilypond[quote,ragged-right] \include "engraver-example.ily" \score { \topVoice \layout { \context { \Voice \remove "Phrasing_slur_engraver" \remove "Slur_engraver" \remove "Script_engraver" \remove "Beam_engraver" \remove "Auto_beam_engraver" } \context { \Staff \remove "Accidental_engraver" \remove "Key_engraver" \remove "Bar_engraver" \remove "Time_signature_engraver" } } } @end lilypond @noindent The @code{Stem_engraver} is notified of any note head coming along. Every time one (or more, for a chord) note head is seen, a stem object is created and connected to the note head. By adding engravers for beams, slurs, accents, accidentals, bar lines, time signature, and key signature, we get a complete piece of notation. @lilypond[quote,ragged-right] \include "engraver-example.ily" \score { \topVoice } @end lilypond This system works well for monophonic music, but what about polyphony? In polyphonic notation, many voices can share a staff. @lilypond[quote,ragged-right] \include "engraver-example.ily" \new Staff << \topVoice \\ \botVoice >> @end lilypond In this situation, the accidentals and staff are shared, but the stems, slurs, beams, etc., are private to each voice. Hence, engravers should be grouped. The engravers for note heads, stems, slurs, etc., go into a group called `Voice context,' while the engravers for key, accidental, bar, etc., go into a group called `Staff context.' In the case of polyphony, a single Staff context contains more than one Voice context. Similarly, multiple Staff contexts can be put into a single Score context. The Score context is the top level notation context. @seealso Program reference: @internalsref{Contexts}. @lilypond[quote,ragged-right] \include "engraver-example.ily" \score { << \new Staff << \topVoice \\ \botVoice >> \new Staff << \pah \\ \hoom >> >> } @end lilypond @node Music representation @section Music representation Ideally, the input format for any high-level formatting system is an abstract description of the content. In this case, that would be the music itself. This poses a formidable problem: how can we define what music really is? Instead of trying to find an answer, we have reversed the question. We write a program capable of producing sheet music, and adjust the format to be as lean as possible. When the format can no longer be trimmed down, by definition we are left with content itself. Our program serves as a formal definition of a music document. The syntax is also the user-interface for LilyPond, hence it is easy to type @example c'4 d'8 @end example @noindent a quarter note C1 (middle C) and an eighth note D1 (D above middle C) @lilypond[quote,fragment] c'4 d'8 @end lilypond On a microscopic scale, such syntax is easy to use. On a larger scale, syntax also needs structure. How else can you enter complex pieces like symphonies and operas? The structure is formed by the concept of music expressions: by combining small fragments of music into larger ones, more complex music can be expressed. For example @lilypond[quote,verbatim,fragment,relative=1] c4 @end lilypond @noindent Chords can be constructed with @code{<<} and @code{>>} enclosing the notes @c < > is not a music expression, @c so we use <<>> iso. <> to drive home the point of @c expressions. Don't change this back --hwn. @example <> @end example @lilypond[quote,fragment,relative=1] \new Voice { <> } @end lilypond @noindent This expression is put in sequence by enclosing it in curly braces @code{@{@tie{}@dots{}@tie{}@}} @example @{ f4 <> @} @end example @lilypond[quote,relative=1,fragment] { f4 <> } @end lilypond @noindent The above is also an expression, and so it may be combined again with another simultaneous expression (a half note) using <<, @code{\\}, and >> @example << g2 \\ @{ f4 <> @} >> @end example @lilypond[quote,fragment,relative=2] \new Voice { << g2 \\ { f4 <> } >> } @end lilypond Such recursive structures can be specified neatly and formally in a context-free grammar. The parsing code is also generated from this grammar. In other words, the syntax of LilyPond is clearly and unambiguously defined. User-interfaces and syntax are what people see and deal with most. They are partly a matter of taste, and also subject of much discussion. Although discussions on taste do have their merit, they are not very productive. In the larger picture of LilyPond, the importance of input syntax is small: inventing neat syntax is easy, while writing decent formatting code is much harder. This is also illustrated by the line-counts for the respective components: parsing and representation take up less than 10% of the source code. @node Example applications @section Example applications We have written LilyPond as an experiment of how to condense the art of music engraving into a computer program. Thanks to all that hard work, the program can now be used to perform useful tasks. The simplest application is printing notes. @lilypond[quote,relative=1,fragment] \time 2/4 c4 c g'4 g a4 a g2 @end lilypond @noindent By adding chord names and lyrics we obtain a lead sheet. @lilypond[quote,ragged-right] << \chords { c2 c f2 c } \new Staff \relative c' { \time 2/4 c4 c g'4 g a4 a g2 } \new Lyrics \lyricmode { twin4 kle twin kle lit tle star2 } >> @end lilypond Polyphonic notation and piano music can also be printed. The following example combines some more exotic constructs. @lilypondfile[quote,ragged-right]{screech-boink.ly} The fragments shown above have all been written by hand, but that is not a requirement. Since the formatting engine is mostly automatic, it can serve as an output means for other programs that manipulate music. For example, it can also be used to convert databases of musical fragments to images for use on websites and multimedia presentations. This manual also shows an application: the input format is text, and can therefore be easily embedded in other text-based formats such as La@TeX{}, HTML, or in the case of this manual, Texinfo. By means of a special program, the input fragments can be replaced by music images in the resulting PDF or HTML output files. This makes it easy to mix music and text in documents. @node About this manual @section About this manual The manual is divided into the following chapters: @itemize @bullet @item @ifhtml The @end ifhtml @emph{@ref{Tutorial}} gives a gentle introduction to typesetting music. First time users should start here. @item @emph{@ref{Working on LilyPond projects}} demonstrates practical uses of LilyPond. @item @emph{@ref{Running LilyPond}} shows how to run LilyPond and its helper programs. In addition, this section explains how to upgrade input files from previous versions of LilyPond. @item @emph{@ref{Basic notation}} discusses topics grouped by notation construct. This section gives details about basic notation that will be useful in almost any notation project. @item @emph{@ref{Instrument-specific notation}} discusses topics grouped by notation construct. This section gives details about special notation that will only be useful for particular instrument (or vocal) groups. @item @emph{@ref{Advanced notation}} discusses topics grouped by notation construct. This section gives details about complicated or unusual notation. @item @emph{@ref{Changing defaults}} explains how to fine tune layout. @item @emph{@ref{Non-musical notation}} discusses non-musical output such as titles, multiple movements, and how to select which MIDI instruments to use. @item @emph{@ref{Spacing issues}} discusses issues which affect the global output, such as selecting paper size or specifying page breaks. @item @emph{@ref{LilyPond-book}} explains the details behind creating documents with in-line music examples, like this manual. @item @emph{@ref{Converting from other formats}} explains how to run the conversion programs. These programs are supplied with the LilyPond package, and convert a variety of music formats to the @code{.ly} format. @item @ifhtml The @end ifhtml @emph{@ref{Literature list}} contains a set of useful reference books for those who wish to know more on notation and engraving. @item @emph{@ref{Example templates}} provides templates of LilyPond pieces. Just cut and paste a template into a file, add notes, and you're done! @end itemize Once you are an experienced user, you can use the manual as reference: there is an extensive index@footnote{If you are looking for something, and you cannot find it in the manual, that is considered a bug. In that case, please file a bug report.}, but the document is also available in @iftex a big HTML page, @end iftex @ifhtml @uref{source/Documentation/user/lilypond.html, one big page}, @end ifhtml which can be searched easily using the search facility of a web browser. @cindex search in manual @cindex using the manual @c FIXME: @c add/integrate glossary, put in list above If you are not familiar with music notation or music terminology (especially if you are a non-native English speaker), it is advisable to consult the glossary as well. @iftex The music glossary explains musical terms, and includes translations to various languages. It is a separate document, available in HTML and PDF. @end iftex @ifnottex The @ref{Top,Music glossary,,music-glossary}, explains musical terms and includes translations to various languages. It is also available in PDF. @end ifnottex @cindex idiom @cindex jargon @cindex terminology @cindex foreign languages @cindex language This manual is not complete without a number of other documents. They are not available in print, but should be included with the documentation package for your platform @itemize @bullet @item @iftex Program reference @end iftex @ifnottex @ref{Top,Program reference,,lilypond-internals}. @end ifnottex The program reference is a set of heavily cross linked HTML pages, which document the nitty-gritty details of each and every LilyPond class, object, and function. It is produced directly from the formatting definitions used. Almost all formatting functionality that is used internally, is available directly to the user. For example, all variables that control thickness values, distances, etc., can be changed in input files. There are a huge number of formatting options, and all of them are described in this document. Each section of the notation manual has a @b{See also} subsection, which refers to the generated documentation. In the HTML document, these subsections have clickable links. @cindex snippets @item @ifnothtml Various input examples. @end ifnothtml @ifhtml @c Works, but link name is not so nice; so write-out macro @c @inputfileref{input/test,Various input examples}. @uref{source/input/test/collated-files.html,Various input examples}. @end ifhtml This collection of files shows various tips and tricks, and is available as a big HTML document, with pictures and explanatory texts included. @item @ifnothtml The regression tests. @end ifnothtml @ifhtml @c Works, but link name is not so nice; so write-out macro @c @inputfileref{input/regression,The regression tests}. @uref{source/input/regression/collated-files.html,The regression tests}. @end ifhtml This collection of files tests each notation and engraving feature of LilyPond in one file. The collection is primarily there to help us debug problems, but it can be instructive to see how we exercise the program. The format is similar to the tips and tricks document. @end itemize In all HTML documents that have music fragments embedded, the LilyPond input that was used to produce that image can be viewed by clicking the image. The location of the documentation files that are mentioned here can vary from system to system. On occasion, this manual refers to initialization and example files. Throughout this manual, we refer to input files relative to the top-directory of the source archive. For example, @file{input/@/test/@/bla@/.ly} may refer to the file @file{lilypond@/-2.8.0/@/input/@/test/@/bla@/.ly}. On binary packages for the Unix platform, the documentation and examples can typically be found somewhere below @file{/usr/@/share/@/doc/@/lilypond/}. Initialization files, for example @file{scm/@/lily@/.scm}, or @file{ly/@/engraver@/-init@/.ly}, are usually found in the directory @file{/usr/@/share/@/lilypond/}. @cindex adjusting output @cindex variables @cindex properties @cindex lilypond-internals @cindex internal documentation @cindex Scheme @cindex extending lilypond @cindex index Finally, this and all other manuals, are available online both as PDF files and HTML from the web site, which can be found at @uref{http://@/www@/.lilypond@/.org/}.