version that you are working on. See TRANSLATION for details.
@end ignore
-@c \version "2.12.0"
+@c \version "2.13.4"
@node Music engraving
@chapter Music engraving
This section covers the overall goals and architecture of
LilyPond.
+@c TODO:
+@c remove 3mm eps bounding box left padding for Sarabande (This will
+@c require adding a new snippet option to lilypond-book.py
+@c check formatting of HTML output
+@c
+
+@c Notes:
+@c Incorrect beaming in the Sarabande is a known bug.
+
@menu
-* Engraving::
+* The LilyPond story::
+* Engraving details::
* Automated engraving::
* What symbols to engrave?::
* Music representation::
* Example applications::
+* Appendix::
@end menu
+@node The LilyPond story
+@unnumberedsec The LilyPond story
+
+Before LilyPond had a community of users around the world, before it had
+been used to produce university course notes or world-premier opera
+performance scores, before there was an essay on music engraving or any
+computer code or even an organized team of developers, LilyPond began
+with a question:
-@node Engraving
-@unnumberedsec Engraving
+@quotation
+Why does most computer output fail to achieve the beauty and balance of
+a hand-engraved score?
+@end quotation
+
+@noindent
+Some of the answers can be found by examining the two scores
+@ifnottex
+below.
+@end ifnottex
+@iftex
+on the following pages.
+@end iftex
+The first score is a beautiful hand-engraved score from 1950 and the
+second is a modern, computer-engraved edition.
+
+@ifnottex
+@noindent
+Bärenreiter BA 320, @copyright{}1950:
+
+@sourceimage{baer-suite1-fullpage,,,png}
+
+@noindent
+Henle no. 666, @copyright{}2000:
+
+@sourceimage{henle-suite1-fullpage,,,png}
+@end ifnottex
+
+The notes here are identical, taken from Bach's first Suite for solo
+cello, but the appearance is different, especially if you print them out
+and view them from a distance.
+@ifnottex
+(The PDF version of this manual has high-resolution images suitable for
+printing.)
+@end ifnottex
+Try reading or playing from each of the scores and you will find that
+the hand-engraved score is more enjoyable to use. It has flowing lines
+and movement, and it feels like a living, breathing piece of music,
+while the newer edition seems cold and mechanical.
+
+It is kind of hard to immediately see what makes the difference with the
+newer edition. Everything looks neat and tiny, possibly even ``better''
+because it looks more computerized and uniform. This really puzzled us
+for quite a while. We wanted to improve computer notation, but we first
+had to figure out what was wrong with it.
+
+The answer lies in the precise, mathematical uniformity of the newer
+edition. Find the bar line in the middle of each line: in the
+hand-engraved score the position of these bar lines has some natural
+natural variation, while in the newer version they line up almost
+perfectly. This is shown in these simplified page layout diagrams,
+traced from the hand-engraved (left) and computer-generated music
+(right):
+
+@quotation
+@iftex
+@sourceimage{pdf/page-layout-comparison,,,}
+@end iftex
+@ifnottex
+@sourceimage{page-layout-comparison,,,png}
+@end ifnottex
+@end quotation
+@noindent
+
+In the computer-generated output, even the individual note heads are
+aligned in vertical columns, making the contour of the melody disappear
+into a rigid grid of musical markings.
+
+There are other differences as well: in the hand-engraved edition the
+vertical lines are all stronger, the slurs lie closer to the note heads,
+and there is more visual variety in the placement of the beams. Although
+such details may seem like nitpicking, the result is a score that is
+easier to read. In the computer-generated output, each line is nearly
+identical and if the musician looks away for a moment, she will be lost
+on the page.
+
+LilyPond was designed to solve the problems we found in existing
+software and to create beautiful music that mimics the finest
+hand-engraved scores. Along the way, we have learned a great deal about
+the work that goes into a well-engraved score. In this essay we describe
+several of those aspects that we have tried to imitate in LilyPond.
+
+@iftex
+@page
+@noindent
+Bärenreiter BA 320, @copyright{}1950:
+
+@sourceimage{baer-suite1-fullpage,16cm,,}
+@page
+@noindent
+Henle no. 666, @copyright{}2000:
+@sp 3
+@sourceimage{henle-suite1-fullpage,16cm,,}
+@page
+@end iftex
+
+@node Engraving details
+@unnumberedsec Engraving details
@cindex engraving
@cindex typography, music
@cindex plate engraving
@cindex music 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, 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 done completely
-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 Bärenreiter 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 Bärenreiter flat has a bold,
-almost voluptuous rounded look. Our flat symbol is designed
-after this one, among others. 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
+The art of music typography is called @emph{(plate) engraving}, a term
+that derives from the manual process of music printing@footnote{Early
+European printers explored several processes, including hand-carved
+wooden blocks, movable type, and engraved sheets of thin metal.
+Typesetting had the advantage of being more easily corrected and
+facilitating the inclusion of text and lyrics, but only engraving
+offered the ability to do unimpeded layout and unanticipated notation.
+In the end, hand-engraved scores became the standard for all printed
+music, with the exception of some hymnals and songbooks where
+typesetting was justified by its ease and economy, even into the
+twentieth century.}. 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, 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 done completely by hand
+and making a correction was cumbersome, so the engraving had to be
+nearly 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.
+
+@quotation
@iftex
-@image{pictures/henle-flat-gray,,4cm}
+@sourceimage{hader-slaan,,7cm,}
@end iftex
@ifnottex
-@image{pictures/henle-flat-gray,,,png}
+@sourceimage{hader-slaan,,,jpg}
@end ifnottex
+@end quotation
-@tab
+LilyPond is inspired by traditional manual engravings published by
+European music publishers in and towards the end of the first half of
+the twentieth century, including Bärenreiter, Duhem, Durand,
+Hofmeister, Peters, and Schott. This is sometimes regarded as the peak
+of traditional musical engraving practice.
+
+@c Now all newly printed music is produced with computers. This has
+@c obvious advantages: prints are cheaper to make, editorial work can be
+@c delivered by email, and the original data can be easily stored.
+@c Unfortunately, computer-generated scores rarely match the quality of
+@c hand-engraved scores. Instead, computer printouts have a bland,
+@c mechanical look, which makes them unpleasant to play from.
+
+@menu
+* Music fonts::
+* Optical spacing::
+* Ledger lines::
+* Optical sizing::
+* Why work so hard?::
+@end menu
+
+@node Music fonts
+@unnumberedsubsec Music fonts
+
+The images below illustrate some differences between traditional
+engraving and typical computer output. The left picture shows a scan of
+a flat symbol from a hand-engraved Bärenreiter edition, while the right
+picture depicts a symbol from an edition of the same music published in
+2000. Although both images are printed in the same shade of ink, the
+earlier version looks darker: the staff lines are heavier, and the
+Bärenreiter flat has a bold, almost voluptuous rounded look. The right
+scan, on the other hand, has thinner lines and a straight layout with
+sharp corners.
+
+@multitable @columnfractions .25 .25 .25 .25
+@item @tab
+@ifnotinfo
@iftex
-@image{pictures/baer-flat-gray,,4cm}
+@sourceimage{baer-flat-gray,,4cm,}
@end iftex
@ifnottex
-@image{pictures/baer-flat-gray,,,png}
+@sourceimage{baer-flat-gray,,,png}
@end ifnottex
@tab
@iftex
-@image{pictures/lily-flat-bw,,4cm}
+@sourceimage{henle-flat-gray,,4cm,}
@end iftex
@ifnottex
-@image{pitcures/lily-flat-bw,,,png}
+@sourceimage{henle-flat-gray,,,png}
@end ifnottex
+
@end ifnotinfo
@ifinfo
-@image{lilypond/pictures/henle-flat-bw,,,,png} @image{lilypond/pictures/baer-flat-bw,,,,png}
-@image{lilypond/pictures/lily-flat-bw,,,,png}
+@sourceimage{henle-flat-bw,,,png}
+@sourceimage{baer-flat-bw,,,png}
+@sourceimage{lily-flat-bw,,,png}
@end ifinfo
+
@item @tab
-Henle (2000)
-@tab
Bärenreiter (1950)
@tab
-LilyPond Feta font (2003)
+Henle (2000)
@end multitable
-
@cindex musical symbols
@cindex font
@cindex blackness
@cindex balance
-@c introduce illustrating aspects of engraving, spacing...
+When we wanted to write a computer program to create music typography,
+there were no musical fonts freely available that could match the
+elegance of our favorite scores. Undeterred, we created a font of
+musical symbols, relying on nice printouts of hand-engraved music. The
+experience helped develop a typographical taste, and it made us
+appreciate subtle design details. Without that experience, we would not
+have realized how ugly the fonts were that we admired at first.
+
+Below is a sample of two music fonts: the upper set is the default font
+in the Sibelius software (the @emph{Opus} font), and the lower set is
+our own LilyPond font.
+
+@quotation
+@iftex
+@sourceimage{pdf/OpusAndFeta,,,}
+@end iftex
+@ifnottex
+@sourceimage{OpusAndFeta,,,png}
+@end ifnottex
+@end quotation
+
+The LilyPond symbols are heavier and their weight is more consistent,
+which makes them easier to read. Fine endings, such as the ones on the
+sides of the quarter rest, should not end in sharp points, but rather
+in rounded shapes. This is because sharp corners of the punching dies
+are fragile and quickly wear out when stamping in metal. Taken together,
+the blackness of the font must be carefully tuned together with the
+thickness of lines, beams and slurs to give a strong yet balanced
+overall impression.
+
+Also, notice that our half-note head is not elliptic but slightly diamond
+shaped. The vertical stem of a flat symbol is slightly brushed, becoming
+wider at the top. The sharp and the natural are easier to distinguish
+from a distance because their angled lines have different slopes and the
+vertical strokes are heavier.
+
+@node Optical spacing
+@unnumberedsubsec Optical 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: once
-using exact mathematical spacing, and once with corrections. Can
-you spot which fragment is which?
+between notes. However, as we saw in the Bach Suite above, many modern
+scores adhere to the durations with mathematical precision, which leads
+to poor results. In the next example a motive is printed twice: the
+first time using exact mathematical spacing, and the second with
+corrections. Which do you prefer?
@cindex optical spacing
-@c file spacing-optical.
-@c need to include it here, because we want two images.
+
@lilypond
\paper {
ragged-right = ##t
\stemNeutral
e'8[ e'8 e'8 e'8]
}
-
\score
{
\music
\layout {
\context {
\Staff
- \override NoteSpacing #'stem-spacing-correction = #0.6
+ \override NoteSpacing #'stem-spacing-correction = #0.0
+ \override NoteSpacing #'same-direction-correction = #0.0
+ \override StaffSpacing #'stem-spacing-correction = #0.0
}
}
}
\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
+ \override NoteSpacing #'stem-spacing-correction = #0.6
}
}
}
@cindex regular spacing
@cindex spacing, regular
-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, however, form
-down-stem/@/up-stem clumps of notes.
-
-
-Musicians are usually more absorbed with performing than with
-studying the looks of a piece of music, so nitpicking
-typographical details may seem academic. 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. A distinct visual
-signature helps to keep musicians from losing their place on the
-page when they look away or have a lapse in concentration.
-
-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 crowding 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,
+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 lower two measures are printed with this correction,
+the upper two measures, however, form down-stem/@/up-stem clumps of
+notes. A master engraver would adjust the spacing as needed to please
+the eye.
+
+Another example of optical spacing is the visual interplay between the
+stems and the bar lines. When an up-stem precedes the bar line, a little
+more space is needed to keep it from feeling crowded:
+
+@lilypond
+\paper {
+ ragged-right = ##t
+}
+
+\score {
+ {
+ c''8 c'' c'' c'' c'' c'' c'' c'' \break
+ a' a' a' a' a' a' a' a'
+ }
+ \layout {
+ \context {
+ \Staff
+ \remove "Time_signature_engraver"
+ \override NoteSpacing #'stem-spacing-correction = #0.7
+ }
+ \context {
+ \Score
+ \remove "Bar_number_engraver"
+ }
+ }
+}
+@end lilypond
+
+@node Ledger lines
+@unnumberedsubsec Ledger lines
+
+@cindex ledger lines
+@cindex collisions
+
+Ledger lines present a typographical challenge: they make it more
+difficult to space musical symbols close together and they must be clear
+enough to identify the pitch at a glance. In the example below, we see
+that ledger lines should be thicker than normal staff lines and that an
+expert engraver will shorten a ledger line to allow closer spacing with
+accidentals. We have included this feature in LilyPond's engraving.
+
+@multitable @columnfractions .25 .25 .25 .25
+@item @tab
+
+@iftex
+@sourceimage{baer-ledger,3cm,,}
+@end iftex
+@ifnottex
+@sourceimage{baer-ledger,,,png}
+@end ifnottex
+
+@tab
+
+@iftex
+@sourceimage{lily-ledger,3cm,,}
+@end iftex
+@ifnottex
+@sourceimage{lily-ledger,,,png}
+@end ifnottex
+
+@end multitable
+
+
+@node Optical sizing
+@unnumberedsubsec Optical sizing
+
+Music may need to be printed in a range of sizes. Originally, this was
+accomplished by creating punching dies in each of the required sizes,
+which meant that each die was designed to look its best at that size.
+With the advent of digital fonts, a single outline can be mathematically
+scaled to any size, which is very convenient, but at the smaller sizes
+the glyphs will appear very light.
+
+In LilyPond, we have created fonts in a range of weights, corresponding
+to a range of music sizes. This is a LilyPond engraving at staff size
+26:
+
+@quotation
+@iftex
+@sourceimage{pdf/size26,,23mm,}
+@end iftex
+@ifnottex
+@sourceimage{size26,,,png}
+@end ifnottex
+@end quotation
+
+@noindent
+and this is the same engraving set at staff size 11, then
+magnified by 236% to print at the same size as the previous example:
+
+@quotation
+@iftex
+@sourceimage{pdf/size11,,23mm,}
+@end iftex
+@ifnottex
+@sourceimage{size11,,,png}
+@end ifnottex
+@end quotation
+
+@noindent
+At smaller sizes, LilyPond uses proportionally heavier lines so the
+music will still read well.
+
+@ignore
+This also allows staves of different sizes to coexist peacefully when
+used together on the same page:
+
+@c TODO: are the stems in this example the right thickness? How should
+@c line weights be scaled for small staves?
+
+@c Grieg's Violin Sonata Op. 45
+@lilypond[indent=1.5cm]
+global = {
+ \time 6/8
+ \key c \minor
+}
+
+\new Score <<
+ \new Staff \with {
+ fontSize = #-4
+ \override StaffSymbol #'staff-space = #(magstep -4)
+ \override StaffSymbol #'thickness = #(magstep -3)
+ }
+ \relative c' {
+ \global
+ \set Staff.instrumentName = #"Violin"
+ c8.(\f^> b16 c d) ees8.(^> d16 c b)
+ g8.(^> b16 c ees) g8-.^> r r
+ R2.
+ }
+ \new PianoStaff <<
+ \set PianoStaff.instrumentName = #"Piano"
+ \new Staff \relative c' {
+ \global
+ s2.
+ s4. s8 r8 r16 <c f aes c>
+ <c f aes c>4.^> <c ees g>8 r r
+ }
+ \new Staff \relative c {
+ \global
+ \clef "bass"
+ << {
+ \once \override DynamicText #'X-offset = #-3
+ <ees g c>2.~->^\f
+ <ees g c>4.~ <ees g c>8
+ } \\ {
+ <c g c,>2.~
+ <c g c,>4.~ <c g c,>8
+ } >>
+ r8 r16 <f, c' aes'>16
+ <f c' aes'>4.-> <c' g'>8 r r
+ }
+ >>
+>>
+@end lilypond
+@end ignore
+
+@node Why work so hard?
+@unnumberedsubsec Why work so hard?
+
+Musicians are usually more absorbed with performing than with studying
+the looks of a piece of music, so nitpicking typographical details may
+seem academic. But it is not. Sheet music is performance material:
+everything is done to aid the musician in letting her perform better,
+and anything that is unclear or unpleasant to read is a hindrance.
+
+Traditionally engraved music uses bold symbols on heavy staff to create
+a strong, well-balanced look that stands out well 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
+crowding 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
+his task. For sheet music this is of double importance because 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
@cindex engraving, automated
@cindex 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?
+This section describes what is required to create software that can
+mimic the layout of engraved scores: a method of explaining good
+layouts to the computer, detailed comparisons with real engravings,
+and enough flexibility to deal with the wide range of challenges
+that printed music can present.
+
+@menu
+* Beauty contests::
+* Improvement by benchmarking::
+* Getting things right::
+* Flexible architecture::
+@end menu
+
+@node Beauty contests
+@unnumberedsubsec Beauty contests
+
+How do we actually make formatting decisions? In other words, which
+of the three configurations should we choose for the following slur?
+
+@lilypond
+\relative c {
+ \clef bass
+ \once \override Slur #'positions = #'(1.5 . 1)
+ e8[( f] g[ a b d,)] r4
+ \once \override Slur #'positions = #'(2 . 3)
+ e8[( f] g[ a b d,)] r4
+ e8[( f] g[ a b d,)] r4
+}
+@end lilypond
+
+There are a few books on the art of music engraving
+available. Unfortunately, they contain rules of simple thumbs and some
+examples. Such rules can be instructive, but they are a far cry from
+an algorithm that we could readily implement in a computer. Following
+the instructions from literature leads to algorithms with lots of
+hand coded exceptions. Doing all this case analysis is a lot of work,
+and often not all cases are covered completely:
+
+@quotation
+@iftex
+@sourceimage{ross-beam-scan,7cm,,}
+@end iftex
+@ifnottex
+@sourceimage{ross-beam-scan,,,.jpg}
+@end ifnottex
+@end quotation
+
+(Image source: Ted Ross, @emph{The Art of Music Engraving})
+
+Rather than trying to write detailed layout rules for every possible
+scenario, we only have to describe the objectives well enough that
+LilyPond can judge the attractiveness of several alternatives. Then,
+for each possible configuration we compute an ugliness score and we
+choose the least ugly configuration.
+
+For example, here are three possible slur configurations, and LilyPond
+has given each one a score in `ugly points'. The first example gets 15.39
+points for grazing one of the notes:
+
+@lilypond
+\relative c {
+ \clef bass
+ \once \override Slur #'positions = #'(1.5 . 1)
+ e8[(_"15.39" f] g[ a b d,)] r4
+}
+@end lilypond
+
+The
+second one is nicer, but the slur doesn't start or end on the note heads.
+It gets 1.71 points for the left side and 9.37 points for the right
+side, plus another 2 points because the slur ascends while the melody
+descends for a total of 13.08 ugly points:
+
+@lilypond
+\relative c {
+ \clef bass
+ \once \override Slur #'positions = #'(2 . 3)
+ e8[(_"13.08" f] g[ a b d,)] r4
+}
+@end lilypond
+
+The final slur gets 10.04
+points for the gap on the right and 2 points for the upward slope, but
+it is the most attractive of the three configurations, so LilyPond
+selects this one:
+
+@lilypond
+\relative c {
+ \clef bass
+ e8[(_"12.04" f] g[ a b d,)] r4
+}
+@end lilypond
+
+This technique is quite general, and is used to make optimal decisions
+for beam configurations, ties and dots in chords, line breaks, and page
+breaks. The results of these decisions can be judged by comparison to
+real engravings.
+
+@node Improvement by benchmarking
+@unnumberedsubsec Improvement by benchmarking
+
+LilyPond's output has improved gradually over time, and it continues to
+improve by comparing its output to hand-engraved scores.
+
+For example, here is one line of a benchmark piece from a
+hand-engraved edition (Bärenreiter BA320):
+
+@iftex
+@sourceimage{baer-sarabande-hires,16cm,,}
+@end iftex
+@ifnottex
+@sourceimage{baer-sarabande,,,png}
+@end ifnottex
+
+@noindent
+and the same quotation as engraved by a very old version of LilyPond
+(version 1.4, May 2001):
+
+@iftex
+@sourceimage{pdf/lily14-sarabande,16cm,,}
+@end iftex
+@ifnottex
+@sourceimage{lily14-sarabande,,,png}
+@end ifnottex
+
+@noindent The LilyPond 1.4 output is certainly readable, but close
+comparison with the hand-engraved score showed a lot of errors in the
+formatting details:
+
+@iftex
+@sourceimage{lily14-sarabande-annotated-hires,16cm,,}
+@end iftex
+@ifnottex
+@sourceimage{lily14-sarabande-annotated,,,png}
+@end ifnottex
+
+@itemize @bullet
+@item there is too much space before the time signature
+@item the stems of the beamed notes are too long
+@item the second and fourth measures are too narrow
+@item the slur is awkward-looking
+@item the trill marks are too big
+@item the stems are too thin
+@end itemize
+
+@noindent
+(There were also two missing note heads, several missing editorial
+annotations, and an incorrect pitch!)
+
+By adjusting the layout rules and font design, the output has improved
+considerably. Compare the same reference score and the output
+from the current version of LilyPond (@version{}):
+
+@iftex
+@sourceimage{baer-sarabande-hires,16cm,,}
+@end iftex
+@ifnottex
+@sourceimage{baer-sarabande,,,png}
+@end ifnottex
+
+@lilypond[staffsize=17.5,line-width=15.9\cm]
+\relative c {
+ \clef "bass"
+ \key d \minor
+ \time 3/4
+ \mergeDifferentlyDottedOn
+ << {\slurDashed d8.-\flageolet( e16) e4.-\trill( d16 e)}
+ \\ {d4_2 a2}
+ >>
+ \slurDashed
+ <f' a, d,>4. e8( d c)
+ \slurSolid
+ bes g' f e16( f g_1 a_2 bes_3 d,_2)
+ \slurDashed
+ cis4.-\trill b8_3( a g)
+ << {\slurDashed d'8.( e16) e4.-\trill( d16 e)}
+ \\ {<f, a>4 a2}
+ >>
+}
+@end lilypond
+
+@noindent
+The current output is not a clone of the reference edition, but it is
+much closer to publication quality that the earlier output.
+
+@node Getting things right
+@unnumberedsubsec Getting things right
+
+We can also measure LilyPond's ability to make music engraving decisions
+automatically by comparing LilyPond's output to the output of a
+commercial software product. In this case we have chosen Finale 2008,
+which is one of the most popular commercial score writers, particularly
+in North America. Sibelius is their major rival and they appear to be
+especially strong in the European market.
+
+For our comparison we chose Bach's Fugue in G minor from the
+Well-Tempered Clavier, Book I, BWV 861, whose opening subject is
+
+@lilypond
+\relative c' {
+ \key g \minor
+ \clef "treble_8"
+ r8 d ees g, fis4 g
+ r8 a16 bes c8 bes16 a bes8
+}
+@end lilypond
+
+@noindent
+
+We made our comparison by engraving the last seven measures of the piece
+(28--34) in Finale and LilyPond. This is the point in the piece where
+the subject returns in a three-part stretto and leads into the closing
+section. In the Finale version, we have resisted the temptation to make
+any adjustments to the default output because we are trying to show the
+things that each software package gets right without assistance.
+
+Many of the differences between the two engravings are visible in
+measures 28--29, as shown here with Finale first and LilyPond second:
+
+@iftex
+@sourceimage{pdf/bwv861mm28-29,14cm,,}
+@end iftex
+@ifnottex
+@sourceimage{bwv861mm28-29,,,png}
+@end ifnottex
+
+@lilypond[staffsize=19.5,line-width=14\cm]
+global = {\key g \minor}
+
+partI = \relative c' {
+ \voiceOne
+ fis8 d' ees g, fis4 g
+ r8 a16 bes c8 bes16 a d8 r r4
+}
+
+partII = \relative c' {
+ \voiceTwo
+ d4 r4 r8 d'16 c bes8 c16 d
+ ees8 d c ees a, r r4
+}
+partIII = \relative c' {
+ \voiceOne
+ r2 r8 d ees g, fis4 g r8 a16 bes c8 bes16 a
+}
+partIV = \relative c {
+ \voiceTwo
+ d4 r r2
+ r8 d ees g, fis4 a
+}
+
+\score {
+ <<
+ % \set Score.barNumberVisibility = #all-bar-numbers-visible
+ % required in 2.13
+ \set Score.currentBarNumber = #28
+ \bar ""
+ \new PianoStaff <<
+ \new Staff = "RH" <<
+ \global
+ \new Voice = "voiceI" { \partI }
+ \new Voice = "voiceII" { \partII }
+ >>
+
+ \new Staff = "LH" <<
+ \clef "bass"
+ \global
+ \new Voice = "voiceIII" { \partIII }
+ \new Voice = "voiceIV" { \partIV }
+ >>
+ >>
+ >>
+ \layout {
+ \context {
+ \Staff
+ \remove "Time_signature_engraver"
+ }
+ \context {
+ \PianoStaff
+ \override StaffGrouper #'between-staff-spacing #'padding = #1
+ }
+ }
+}
+@end lilypond
-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.
+Some shortcomings in the unedited Finale output include:
+@itemize @bullet
+@item Most of the beams extend too far off the staff. A beam that points
+towards the center of the staff should have a length of about one
+octave, but engravers shorten this when the beam points away from the
+staff in multi-voice music. The Finale beaming can be easily improved
+with the Patterson Beams plug-in, but we elected to skip that step for
+this example.
+@item Finale doesn't adjust the positions of interlocking note heads,
+which makes the music extremely difficult to read when the upper and
+lower voices exchange positions temporarily:
+
+@lilypond
+collide = \once \override NoteColumn #'force-hshift = #0
+\new Score <<
+ \new Voice = "sample" \relative c''{
+ \key g \minor
+ <<
+ {\voiceOne g4 \collide g4}
+ \new Voice {\voiceTwo bes \collide bes}
+ >>
+ }
+ \new Lyrics \lyricsto "sample" \lyricmode { "good " " bad" }
+>>
+@end lilypond
+
+@item Finale has placed all of the rests at fixed heights on the staff.
+The user is free to adjust them as needed, but the software makes no
+attempt to consider the content of the other voice. As luck would have
+it, there are no true collisions between notes and rests in this example,
+but that has more to do with the positions of the notes than the rest.
+In other words, Bach deserves more credit for avoiding a complete
+collision than Finale does.
+
+@end itemize
+
+This example is not intended to suggest that Finale cannot be used to
+produce beautiful output. On the contrary, in the hands of a skilled
+user it can and does, but it requires skill and time. One of the
+fundamental differences between LilyPond and commercial score writers is
+that LilyPond hopes to reduce the amount of human intervention to an
+absolute minimum, while other packages try to provide an attractive
+interface in which to make these types of edits.
+
+One particularly glaring omission we found in the Finale sample is a
+missing flat in measure 33:
+
+@quotation
+@iftex
+@sourceimage{pdf/bwv861mm33-34-annotate,7.93cm,,}
+@end iftex
+@ifnottex
+@sourceimage{bwv861mm33-34-annotate,,,png}
+@end ifnottex
+@end quotation
+
+@noindent
+The flat symbol is required to cancel out the natural in the same
+measure, but Finale misses it because it occurred in a different voice.
+The user must not only remember to run a beaming plug-in and respace the
+note heads and rests, she must also check each measure for cross-voice
+accidentals if she is to avoid interrupting a rehearsal for an engraving
+error.
+
+If you are interested in examining these examples in more detail, the
+full seven-measure excerpt can be found at the end of this essay in
+engravings by Finale and LilyPond along with four different published
+engravings. Close examination reveals that there is some acceptable
+variation among the hand-engravings, but that LilyPond compares
+reasonably well to that acceptable range. There are still some
+shortcomings in the LilyPond output, for example, it appears a bit too
+aggressive in shortening some of the stems, so there is room for further
+development and fine-tuning.
+
+Of course, 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. 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. Where
+manual adjustments are needed, LilyPond's structure has been designed
+with that flexibility in mind.
+
+@node Flexible architecture
+@unnumberedsubsec Flexible architecture
When we started, we wrote the LilyPond program entirely in the C++
programming language; the program's functionality was set in stone
<<
\new Staff \fragment
\new Staff \with {
- \override Beam #'thickness = #0.3
+ \override Beam #'beam-thickness = #0.3
\override Stem #'thickness = #0.5
\override Bar #'thickness = #3.6
\override Tie #'thickness = #2.2
\set autoBeaming = ##f
\time 2/4
<d f g>4
- \once \override NoteHead #'stencil = #ly:note-head::brew-ez-stencil
+ \once \override NoteHead #'stencil = #note-head::brew-ez-stencil
\once \override NoteHead #'font-size = #-7
\once \override NoteHead #'font-family = #'sans
\once \override NoteHead #'font-series = #'bold
\key c \minor
\set subdivideBeams = ##f
\override Stem #'french-beaming = ##t
- \override Beam #'thickness = #0.3
+ \override Beam #'beam-thickness = #0.3
\override Stem #'thickness = #4.0
g'16[ b16 fis16 g16]
<< \makeClusters {
TODO: add extra chapter for computer aesthetics?
+
+@page
+@node Appendix
+@unnumberedsec Appendix
+
+This appendix contains four reference engravings and two
+software-engraved versions of Bach's Fugue in G minor from the
+Well-Tempered Clavier, Book I, BWV 861 (the last seven measures).
+
+@noindent
+Bärenreiter BA5070 (Neue Ausgabe Sämtlicher Werke, Serie V, Band 6.1,
+1989):
+
+@iftex
+@sourceimage{bwv861-baer,16cm,,}
+@end iftex
+@ifnottex
+@sourceimage{bwv861-baer-small,,,png}
+@end ifnottex
+
+@noindent
+Bärenreiter BA5070 (Neue Ausgabe Sämtlicher Werke, Serie V, Band 6.1,
+1989), an alternate musical source. Aside from the textual differences,
+this demonstrates slight variations in the engraving decisions, even
+from the same publisher and edition:
+
+@iftex
+@sourceimage{bwv861-baer-alt,16cm,,}
+@end iftex
+@ifnottex
+@sourceimage{bwv861-baer-alt-small,,,png}
+@end ifnottex
+
+@noindent
+Breitkopf & Härtel, edited by Ferruccio Busoni (Wiesbaden, 1894), also
+available from the Petrucci Music Library (IMSLP #22081). The editorial
+markings (fingerings, articulations, etc.) have been removed for clearer
+comparison with the other editions here:
+
+@iftex
+@sourceimage{bwv861-breitkopf,16cm,,}
+@end iftex
+@ifnottex
+@sourceimage{bwv861-breitkopf-small,,,png}
+@end ifnottex
+
+@noindent
+Bach-Gesellschaft edition (Leipzig, 1866), available from the Petrucci
+Music Library (IMSPL #02221):
+
+@iftex
+@sourceimage{bwv861-gessellschaft,16cm,,}
+@end iftex
+@ifnottex
+@sourceimage{bwv861-gessellschaft-small,,,png}
+@end ifnottex
+
+@noindent
+Finale 2008:
+
+@iftex
+@sourceimage{pdf/bwv861-finale2008a,,,}
+@end iftex
+@ifnottex
+@sourceimage{bwv861-finale2008a,,,png}
+@end ifnottex
+
+@sp 4
+@noindent
+LilyPond, version @version{}:
+
+@lilypond[staffsize=14.3,line-width=15.9\cm]
+global = {\key g \minor}
+
+partI = \relative c' {
+ \voiceOne
+ fis8 d' ees g, fis4 g
+ r8 a16 bes c8 bes16 a d8 r r4
+ r2 r8 d16 ees f8 ees16 d
+ ees4 ~ ees16 d c bes a4 r8 ees'16 d
+ c8 d16 ees d8 e16 fis g8 fis16 g a4 ~
+ a8 d, g f ees d c bes
+ a2 g\fermata \bar "|."
+}
+
+partII = \relative c' {
+ \voiceTwo
+ d4 r4 r8 d'16 c bes8 c16 d
+ ees8 d c ees a, r r4
+ r8 fis16 g a8 g16 fis g2 ~
+ g2 r8 d' ees g,
+ fis4 g r8 a16 bes c8 bes16 a
+ bes4. <g b>8 <a c> r <d, g> r
+ <ees g>4 <d fis> d2
+}
+partIII = \relative c' {
+ \voiceOne
+ r2 r8 d ees g, fis4 g r8 a16 bes c8 bes16 a
+ bes2 ~ bes8 b16 a g8 a16 b
+ c4 r r2
+ R1
+ r8 d ees g, fis4 g
+ r8 a16 bes c8 bes16 a b2
+}
+partIV = \relative c {
+ \voiceTwo
+ d4 r r2
+ r8 d ees g, fis4 a
+ d,8 d'16 c bes8 c16 d ees2 ~
+ ees8 ees16 d c8 d16 ees fis,8 a16 g fis8 g16 a
+ d,8 d'16 c bes8 c16 d ees8 c a fis'
+ g f ees d c bes a g
+ c a d d, g2\fermata
+}
+
+\score {
+ <<
+ % \set Score.barNumberVisibility = #all-bar-numbers-visible
+ % required in 2.13
+ \set Score.currentBarNumber = #28
+ \bar ""
+ \new PianoStaff <<
+ \new Staff = "RH" <<
+ \global
+ \new Voice = "voiceI" { \partI }
+ \new Voice = "voiceII" { \partII }
+ >>
+
+ \new Staff = "LH" <<
+ \clef "bass"
+ \global
+ \new Voice = "voiceIII" { \partIII }
+ \new Voice = "voiceIV" { \partIV }
+ >>
+ >>
+ >>
+ \layout {
+ \context {
+ \Staff
+ \remove "Time_signature_engraver"
+ }
+ \context {
+ \PianoStaff
+ \override StaffGrouper #'between-staff-spacing #'padding = #1
+ }
+ }
+}
+@end lilypond
projects / lilypond.git / blobdiff