-@c -*-texinfo-*-
-
+@c -*- coding: utf-8; mode: texinfo; -*-
+@c This file is part of lilypond.tely
@node Introduction
@chapter Introduction
-There are a lot of programs that let you print sheet music with a
-computer, but most of them do not do good job. Most computer
-printouts have a bland, mechanical look, and are unpleasant to play
-from. If you agree with us on that, then you will like LilyPond: we
-have tried to capture the original look of hand-engraved music. We
-have tuned our algorithms, font-designs, and program settings to make
-the program produce prints that match the quality of the old editions
-we love to see and love to play from.
-
@menu
-* Notation in LilyPond ::
-* Engraving in LilyPond::
-* Typography and program architecture::
+* Engraving::
+* Automated engraving::
+* What symbols to engrave?::
* Music representation::
* Example applications::
* About this manual::
@end menu
-@node Notation in LilyPond
-@section Notation in LilyPond
+@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 .05 .3 .3 .3 .05
+@item @tab
+@ifnotinfo
+@iftex
+@image{henle-flat-gray,,8cm}
+@end iftex
+@ifnottex
+@image{henle-flat-gray,,,png}
+@end ifnottex
+
+@tab
+@iftex
+@image{baer-flat-gray,,8.4cm}
+@end iftex
+@ifnottex
+@image{baer-flat-gray,,,png}
+@end ifnottex
+@tab
+@iftex
+@image{lily-flat-bw,,8cm}
+@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
-@cindex engraving
-@cindex typography
+@item @tab
+Henle (2000)
+@tab
+B@"{a}renreiter (1950)
+@tab
+LilyPond Feta font (2003)
+@end multitable
-Printing sheet music consists of two non-trivial tasks. First, one has
-to master music notation: the science of knowing which symbols to use
-for what. Second, one has to master music engraving: the art of
-placing symbols such that the result looks pleasing.
-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 change to express the
-innovations of contemporary notation. Hence, it encompasses some 500
-years of music. Its applications range from monophonic melodies to
-monstruous counterpoint for large orchestras.
+@cindex musical symbols
+@cindex font
+@cindex blackness
+@cindex balance
-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 make a strict
-distinction between notation, @emph{what} symbols to use, and
-engraving, @emph{where} to put them. Anything related to the second
-question is considered ``engraving'' (i.e. typography).
-
-For tackling the first problem, notation, we have broken up the
-problem into digestible (and programmable) chunks: every type of
-symbol is handled by a separate program module, a so-called plug-in.
-Each plug-in are completely modular and independent, so each can be
-developed and improved separately. When put together, the plug-ins
-can solve the music notation program in cooperation. People that put
-graphics to musical ideas are called copyists or engravers, so by
-analogy, each plug-in is also called @code{engraver}.
-
-In the following example, we see how we start out with a note head
-engraver.
-
-@lilypond[]
-\include "engraver-example.lyinc"
-
-\score { \topVoice
+@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 {
- \translator { \VoiceContext
- \remove "Stem_engraver"
- \remove "Phrasing_slur_engraver"
- \remove "Slur_engraver"
- \remove "Script_engraver"
- \remove "Beam_engraver"
- \remove "Auto_beam_engraver"
-
- }
- \translator { \StaffContext
- \remove "Accidental_engraver"
- \remove "Key_engraver"
- \remove "Clef_engraver"
- \remove "Bar_engraver"
- \remove "Time_signature_engraver"
- \remove "Staff_symbol_engraver"
- \consists "Pitch_squash_engraver"
- }
-
-}
+ ragged-right = ##t
+ indent = #0.0
}
-@end lilypond
-Then a @code{Staff_symbol_engraver} adds the staff:
+music = {
+ c'4 e''4 e'4 b'4 |
+ \stemDown
+ b'8[ e'' a' e'']
+ \stemNeutral
+ e'8[ e'8 e'8 e'8]
+}
-@lilypond[]
-\include "engraver-example.lyinc"
+\score
+{
+ \music
+ \layout {
+ \context {
+ \Staff
+ \override NoteSpacing #'stem-spacing-correction = #0.6
+ }
+ }
+}
+@end lilypond
-\score { \topVoice
+@lilypond
\paper {
- \translator { \VoiceContext
- \remove "Stem_engraver"
- \remove "Phrasing_slur_engraver"
- \remove "Slur_engraver"
- \remove "Script_engraver"
- \remove "Beam_engraver"
- \remove "Auto_beam_engraver"
-
- }
- \translator { \StaffContext
- \remove "Accidental_engraver"
- \remove "Key_engraver"
- \remove "Clef_engraver"
- \remove "Bar_engraver"
- \consists "Pitch_squash_engraver"
- \remove "Time_signature_engraver"
- }
-
-}
+ 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
- The @code{Clef_engraver} defines a reference point for the staff:
+@cindex regular rhythms
+@cindex regular spacing
-@lilypond[]
-\include "engraver-example.lyinc"
+The fragment only uses quarter notes: 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 first two measures are
+printed with this correction, the last two measures without. The notes
+in the last two measures form down-stem/@/up-stem clumps of notes.
-\score { \topVoice
-\paper {
- \translator { \VoiceContext
- \remove "Stem_engraver"
- \remove "Phrasing_slur_engraver"
- \remove "Slur_engraver"
- \remove "Script_engraver"
- \remove "Beam_engraver"
- \remove "Auto_beam_engraver"
- }
- \translator { \StaffContext
- \remove "Accidental_engraver"
- \remove "Key_engraver"
- \remove "Bar_engraver"
- \remove "Time_signature_engraver"
- }
-
-}
+@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 <e g b>4_>-\arpeggio
+ \override Arpeggio #'direction = #RIGHT
+ \stemUp <e g b>4^>-\arpeggio
}
@end lilypond
-And the @code{Stem_engraver} adds stems:
-
-@lilypond[]
-\include "engraver-example.lyinc"
+@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
-\score { \topVoice
-\paper {
- \translator { \VoiceContext
- \remove "Phrasing_slur_engraver"
- \remove "Slur_engraver"
- \remove "Script_engraver"
- \remove "Beam_engraver"
- \remove "Auto_beam_engraver"
- }
- \translator { \StaffContext
- \remove "Accidental_engraver"
- \remove "Key_engraver"
- \remove "Bar_engraver"
- \remove "Time_signature_engraver"
- }
-}
+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]
+#(define (mc-squared grob orig current)
+ (let ((interfaces (ly:grob-property grob 'interfaces))
+ (pos (ly:grob-property grob 'staff-position)))
+ (if (and (memq 'note-head-interface interfaces)
+ (memq pos '(-2 -3 -5)))
+ (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
+ <d f g>4
+ \once \override NoteHead #'stencil = #ly:note-head::brew-ez-stencil
+ <d f g>
+ \once \override NoteHead #'style = #'cross
+ <d f g>
+ \applyOutput #'Voice #mc-squared
+ <d f g>
+ <<
+ { d8[ es-( fis^^ g] fis2-) }
+ \repeat unfold 5 { \applyOutput #'Voice #mc-squared s8 }
+ >>
}
@end lilypond
-The @code{Stem_engraver} is notified of any note head coming along.
-Every time one (or more, for a chord) note head(s) is seen, a stem
-object is created, and attached 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[]
-\include "engraver-example.lyinc"
+@node What symbols to engrave?
+@section What symbols to engrave?
-\score { \topVoice }
-@end lilypond
+@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.
-This system works well for monophonic music, but what about
-polyphony? In polyphonic notation, many voices can share a staff.
+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.
-@lilypond[]
-\include "engraver-example.lyinc"
-\score { \context Staff << \topVoice \\ \botVoice >> }
-@end lilypond
+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"
-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 head, 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. In polyphonic notation, many voices can share a staff:
-Similarly, more Staff contexts can be put into a single Score context.
-
-@lilypond[]
-\include "engraver-example.lyinc"
\score {
-<< \new Staff << \topVoice \\ \botVoice >>
-\new Staff << \pah \\ \hoom >>
- >>
+ \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"
-@node Engraving in LilyPond
-@section Engraving in LilyPond
-
-
-The term music engraving derives from the traditional process of music
-printing. Only a few decades ago, sheet music was made by cutting and
-stamping the music into zinc or pewter plates, in mirror image. The plate
-would be inked, and 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
-corrections was cumbersome, so engraving had to be done correctly in
-one go. Of course, this was a highly specialized skill, much more so
-than the traditional process of printing books.
-@cindex craftsmanship
-@cindex master
-In the traditional German system of craftsmanship six years of full-time
-training, more than any other craft, were required before a student
-could call himself a master of the art. After that many more years of
-practical experience were needed to become an established music
-engraver. Even today, with the use of high-speed computers and
-advanced software, music requires lots of manual fine tuning before it
-is acceptable for publication.
-
-
-Sheet music is performance material: everything is done to aid the
-musician in letting him perform better. Music often is far away from
-its reader---it might be on a music stand. To make it clearly
-readable, traditionally printed sheet music always uses bold symbols,
-on heavy staff lines, and is printed on large sheets of paper. This
-``strong'' look is also present in the horizontal spacing. To
-minimize the number of page breaks, (hand-engraved) sheet music is
-spaced very tightly. Yet, by a careful distribution of white space,
-the feeling of balance is retained, and a clutter of symbols is
-avoided.
-
-
-We have used these observations in designing LilyPond. The images
-below show the flat symbol. On the left, a scan from a Henle edition,
-which was made by a computer, and in the center is the flat from a
-hand engraved B@"{a}renreiter edition of the same music. The left scan
-illustrates typical flaws of computer print: the symbol is much
-lighter, the staff lines are thinner, and the glyph has a straight
-layout with sharp corners. By contrast, the B@"{a}renreiter has a bold
-and almost voluptuous rounded look. Our flat symbol is designed
-after, among others, this one. It is tuned it to harmonize with the
-thickness of our staff lines, which are also much thicker than Henle's
-lines.
-
-@multitable @columnfractions .1 .3 .3 .3
-@item @tab
-@iftex
-@image{henle-flat-bw,4cm}
-@end iftex
-@html
-<img src=henle-flat-bw.png>
-@end html
-
-@tab
-@iftex
-@image{baer-flat-bw,4cm}
-@end iftex
-@html
-<img src=baer-flat-bw.png>
-@end html
-
-@tab
-@iftex
-@image{lily-flat-bw,4cm}
-@end iftex
-@html
-<img src=lily-flat-bw.png>
-@end html
+\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
-@item @tab
-Henle (2000)
-@tab
-B@"{a}renreiter (1950)
-@tab
-LilyPond Feta font (2003)
+@noindent
+the @code{Clef_engraver} defines a reference point for the staff
-@end multitable
+@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
-@cindex musical symbols
-@cindex font
-@cindex blackness
-@cindex balance
+@noindent
+and the @code{Stem_engraver} adds stems.
-In spacing, the distribution of space should reflect the durations
-between notes. However, adhering with mathematical precision to the
-duration will lead to a poor result. Shown here is an example of a
-motive, printed twice. It is printed using exact mathematical spacing,
-and with some corrections. Can you spot which fragment is which?
+@lilypond[quote,ragged-right]
+\include "engraver-example.ily"
-@cindex optical spacing
-@lilypond[noindent]
- \score { \notes {
- \property Staff.NoteSpacing \set #'stem-spacing-correction
- = #0.6
- c'4 e''4 e'4 b'4 |
- \stemDown b'4 e''4 a'4 e''4| \stemBoth
- \bar "||"
- \property Staff.NoteSpacing \override #'stem-spacing-correction
- = #0.0
- \property Staff.StaffSpacing \override #'stem-spacing-correction
- = #0.0
- c'4 e''4 e'4 b'4 |
- \stemDown b'4 e''4 a'4 e''4|
+\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"
}
- \paper { raggedright = ##t } }
+ }
+}
@end lilypond
-@cindex regular rhythms
-@cindex regular spacing
+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.
-The fragment only uses quarter notes: 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-up
-combination should be put closer together, all depending on the
-combined vertical positions of the notes. The first two measures are
-printed with this correction, the last two measures without. The notes
-in the last two measures form down-stem/up-stems clumps of notes.
-
-@node Typography and program architecture
-@section Typography and program architecture
-
-Producing good engraving requires skill and knowledge. As the
-previous examples show, there is a lot of subtlety involved in music
-engraving, and unfortunately, only a small fraction of these details
-are documented. Master engravers must learn all these details from
-experience or from other engravers, which is why it takes so long to
-become a master. As an engraver gets older and wiser, he will be able
-to produce better and more complex pieces. A similar situation is
-present when putting typographical knowledge into a computer program.
-It is not possible to come up with a definitive solution for a problem
-at the first try. Instead, we start out with simple solution that
-might cover 75% of the cases, and gradually refine that solution over
-the course of months or years, so 90 or 95 % of the cases are
-handled.
-
-This has an important implication for the design of the program: at
-any time, almost every piece of formatting code must be considered as
-temporary. When the need arises, it is to be replaced a solution that
-will cover even more cases. A ``plug-in'' architecture is a clean
-way to accomplish this. This is an architecture where new pieces of
-code can be inserted in the program dynamically. In such a program, a
-new solution can be developed along-side the existing code. For
-testing, it is plugged in, but for production use, the old solution is
-used. The new module can be perfected separately until it is better
-than the existing solution, at which point it replaces the old one.
-
-Until that time, users must have a way to deal with imperfections:
-these 25%, 10% or 5% of the cases that are not handled
-automatically. In these cases, a user must be able to override
-formatting decisions. To accomplish this we store decisions in generic
-variables, and let the user manipulate thosed. For example, consider
-the following fragment of notation:
+@lilypond[quote,ragged-right]
+\include "engraver-example.ily"
+\score { \topVoice }
+@end lilypond
-@lilypond
-\score { \notes \relative c'' {
-\stemUp
- a4_\f f,8
- }
-\paper { raggedright = ##t }
- }
+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
-@noindent
-The position of the forte symbol is slightly awkward, because it is
-next to the low note, whereas dynamics should be below notes in
-general. This may be remedied by inserting extra space between the
-high note and the `f', as shown in this example:
+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.
-@lilypond
-\score { \notes \relative c'' {
-\stemUp
- \once\property Voice. DynamicLineSpanner \override #'padding = #4.0
- a4_\f f,8
- }
-\paper { raggedright = ##t }
- }
+@seealso
+
+Program reference: @internalsref{Contexts}.
+
+@lilypond[quote,ragged-right]
+\include "engraver-example.ily"
+\score {
+ <<
+ \new Staff << \topVoice \\ \botVoice >>
+ \new Staff << \pah \\ \hoom >>
+ >>
+}
@end lilypond
-This was achieved with the following input statement:
+@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
- \once \property Voice. DynamicLineSpanner \override #'padding = #4.0
+c'4 d'8
@end example
-It increases the amount of space (@code{padding}) between the note and
-the dynamic symbol to 4.0 (which is measured in staff space, so 4.0
-equals the height of a staff). The keyword @code{\once} indicates that
-this is a tweak: it is only done one time.
-
-Both design aspects, a plug-in architecture, and formatting variables,
-are built on top of GUILE, an interpreter for the programming language
-Scheme, which is a member of the LISP family. Variables are stored as
-Scheme objects, and attached to graphical objects such as note heads
-and stems. The variables are a means to adjust formatting details in
-individual cases, but they are used in a more general manner.
-
-Consider the case of a publisher that is not satisfied with the in the
-default layout, and wants heavier stems. Normally, they are @code{1.3}
-times the thickness of staff lines, but suppose that their editions
-require them to be twice the thickness of the staff lines. The same
-mechanism can be used to adjust a setting globally. By issuing the
-following command, the entire piece is now formatted with thicker stems:
+
+@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
- \property Score.Stem \override #'thickness = #3.0
+<<c4 d4 e4>>
@end example
-@lilypond
-\score { \notes \relative c'' {
- \property Score.Stem \override #'thickness = #3.0
- \once\property Voice. DynamicLineSpanner \override #'padding = #4.0
-\stemUp
- a4_\f f,8
- }
-\paper { raggedright = ##t }
- }
+@lilypond[quote,fragment,relative=1]
+\new Voice { <<c4 d4 e>> }
@end lilypond
@noindent
-In effect, by setting these variables, users can define their own
-layout styles.
-
-``Plug-ins'' are also implemented using Scheme. A formatting
-``plug-in'' takes the form of a function written in Scheme (or a C++
-function made available as a Scheme function), and it is also stored
-in a variable. For example, the placement of the forte symbol in the
-example above is calculated by the function
-@code{Side_position_interface::aligned_side}. If we want to replace
-this function by a more advanced one, we could issue
+This expression is put in sequence by enclosing it in curly braces
+@code{@{@tie{}@dots{}@tie{}@}}
+
@example
- \property Voice.DynamicLineSpanner \override #'Y-offset-callbacks
- = #(list gee-whiz-gadget)
+@{ f4 <<c4 d4 e4>> @}
@end example
+@lilypond[quote,relative=1,fragment]
+{ f4 <<c d e4>> }
+@end lilypond
+
@noindent
-Now, the formatting process will trigger a call to our new
-@code{gee-whiz-gadget} function when the position of the f symbol has
-to be determined.
+The above is also an expression, and so it may be combined
+again with another simultaneous expression (a half note) using <<,
+@code{\\}, and >>
-The full scope of this functionality certainly is intimidating, but
-there is no need to fear: normally, it is not necessary to define
-style-sheets or rewrite formatting functions. In fact, LilyPond gets a
-lot of formatting right automatically, so adjusting individual layout
-situations is not needed often at all.
+@example
+<< g2 \\ @{ f4 <<c4 d4 e4>> @} >>
+@end example
+@lilypond[quote,fragment,relative=2]
+\new Voice { << g2 \\ { f4 <<c d e>> } >> }
+@end lilypond
-@node Music representation
-@section Music representation
+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.
-Our premise is that LilyPond is a system that does music formatting
-completely automatically. Under this assumption, the output does not
-have to be touched up. Consequently, an interactive display of the
-output, where it is possible to reposition notation elements, is
-superfluous. This implies that the program should be a batch program:
-the input is entered in a file, which then is @emph{compiled}, i.e.
-put through the program. The final output is produced as a file ready
-to view or print. The compiler fills in all the details of the
-notation, those details should be left out of the input file. In other
-words, the input should mirror the content as closely as possible. In
-the case of music notation the content is the music itself, so that is
-what the input should consist of.
-
-On paper this theory sounds very good. In practice, it opens a can of
-worms. What really @emph{is} music? Many philosophical treatises must
-have been written on the subject. Instead of losing ourselves in
-philosophical arguments over the essence of music, we have reversed
-the question to yield a more practical approach. Our assumption is
-that the printed score contains all of the music of piece. We build a
-program that uses some input format to produce such a score. Over the
-course of time, the program evolves. While this happens, we can remove
-more and more elements of the input format: as the program improves,
-it can fill in irrelevant details of the input by itself. At some
-(hypothetical) point, the program is finished: there is no possibility
-to remove any more elements from the syntax. What we have left is by
-definition exactly the musical meaning of the score.
-
-There are also more practical concerns. Our users have to key in the
-music into the file directly, so the input format should have a
-friendly syntax: a quarter note C is entered as @code{c4}, the code
-@code{r8.} signifies a dotted eighth rest.
-
-Notes and rests form the simplest musical expressions in the input
-syntax. More complex constructs are produced by combining them into
-compound structures. This is done in much the same way that complex
-mathematical formulas are built from simple expressions such as
-numbers and operators.
-
-In effect, the input format is a language, and the rules of that
-language can be specified succinctly with a so-called context-free
-grammar. The grammar formally specificies what types of input form
-valid `sentences'. Reading such languages, and splitting them into
-grammatical structures is a problem with standard solutions.
-Moreover, rigid definitions make the format easier to understand: a
-concise formal definition permits a simple informal description.
-
-The user-interface of LilyPond is its syntax. That part is what users
-see most. As a results, some users think that music representation is
-a very important or interesting problem. In reality, less than 10% of
-the source code of the program handles reading and representing the
-input, and they form the easy bits of the program. In our opinion,
-producing music notation, and formatting it prettily are much more
-interesting and important than music representation: solving
-these problems takes up most of the bulk of the code, and they are the
-most difficult things to get right.
@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
+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:
+simplest application is printing notes.
-@lilypond[relative=1]
- \time 2/4 c4 c g'4 g a4 a g2
+@lilypond[quote,relative=1,fragment]
+\time 2/4 c4 c g'4 g a4 a g2
@end lilypond
-By adding chord names and lyrics we obtain a lead sheet:
-
-@lilypond[raggedright]
-\score { <<
- \context ChordNames \chords { c2 c f2 c }
- \notes \relative c' { \time 2/4 c4 c g'4 g a4 a g2 }
- \context Lyrics \lyrics { twin4 kle twin kle lit tle star2 } >> }
+@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:
+Polyphonic notation and piano music can also be printed. The following
+example combines some more exotic constructs.
-@lilypondfile{screech-boink.ly}
+@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
+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
+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 plain 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 PostScript or HTML output files. This makes it easy to
-mix music and text in documents.
+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.
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
@ifhtml
The
@end ifhtml
-@emph{@ref{Notation manual}}
-discusses topics grouped by notation construct. Once you master the
-basics, this is the place to look up details.
+@emph{@ref{Tutorial}}
+gives a gentle introduction to typesetting music. First time
+users should start here.
+
@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.
+@emph{@ref{Working on LilyPond projects}}
+demonstrates practical uses of LilyPond.
+
@item
-@ifhtml
- The
- @end ifhtml
-@emph{@ref{Technical manual}}
-@c
-discusses the general design of the program, and how to extend its
-functionality.
+@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
-@ifhtml
-The chapter
-@end ifhtml
-@emph{@ref{Invoking LilyPond}} explains how to run LilyPond and its helper
-programs.
+@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
-@ifhtml
-The
-@end ifhtml
-@emph{@ref{lilypond-book manual}}
-explains the details behind creating documents with in-line music
-examples (like this manual).
+@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{Global issues}}
+discusses issues which affect the global output, such as selecting
+paper size or which MIDI instruments to use.
+
+@item
+@emph{@ref{LilyPond-book}} explains the details behind creating
+documents with in-line music examples, like this manual.
@item
-@ifhtml
-The chapter
-@end ifhtml
@emph{@ref{Converting from other formats}}
-explains how to run the conversion programs. These programs
+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. In addition, this section explains
-how to upgrade input files from previous versions of LilyPond.
+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
-@ifnothtml
+@iftex
a big HTML page,
-@end ifnothtml
+@end iftex
@ifhtml
-@uref{../lilypond.html, a big HTML page}
+@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), then it is
-advisable to consult the glossary as well. The glossary explains
-musical terms, and includes translations to various languages. It is a
-@ifhtml
-@uref{../music-glossary.html,separate document}.
-@end ifhtml
-@ifnothtml
-separate document, available in HTML and PDF.
-@end ifnothtml
+(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 language
-This manual is not complete without a number of other documents. They
+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:
+documentation package for your platform
@itemize @bullet
@item
+@iftex
Program reference
-@ifhtml
-(available @uref{../lilypond-internals/lilypond-internals.html,here})
-@end ifhtml
+@end iftex
+@ifnottex
+@ref{Top,Program reference,,lilypond-internals}.
+@end ifnottex
-The program reference is a set of heavily crosslinked HTML pages,
-which documents the nit-gritty details of each and every LilyPond
-class, object and function. It is produced directly from the
+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 thicknesses, distances, etc, can be changed in input
-files. There are a huge number of formatting options, and all of them
-are described in the generated documentation. Each section of the
+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
-the generated documentation. In the HTML document, these subsections
+generated documentation. In the HTML document, these subsections
have clickable links.
+@cindex snippets
@item
- Templates
-@ifhtml
-(available @uref{../../../input/template/out-www/collated-files.html,here})
-@end ifhtml
-
-After you have gone through the tutorial, you should be able to write
-input files. In practice, writing files from scratch turns out to be
-intimidating. To give you a headstart, we have collected a number of
-often-used formats in example files. These files can be used as a
-start: simply copy the template, and add notes in the appropriate
-places.
-
-@item
- Various input examples
+@ifnothtml
+Various input examples.
+@end ifnothtml
@ifhtml
-(available @uref{../../../../input/test/out-www/collated-files.html,here})
+@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
-@cindex snippets
-
-These small files show various tips and tricks, and are available as a
-big HTML document, with pictures and explanatory texts included.
+This collection of files shows various tips and tricks, and is
+available as a big HTML document, with pictures and explanatory texts
+included.
@item
- The regression tests
+@ifnothtml
+The regression tests.
+@end ifnothtml
@ifhtml
-(available @uref{../../../input/regression/out-www/collated-files.html,here})
+@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 excercise the
-program. The format is like the tips and tricks document.
-
+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
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-1.7.19/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/}.
+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 internal documentation
@cindex Scheme
@cindex extending lilypond
-@cindex bugreport
@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/}.
+@uref{http://@/www@/.lilypond@/.org/}.
-@cindex website
-@cindex URL
projects / lilypond.git / blobdiff