From 428d29a3576aed91db47413e94c96214e8c201f3 Mon Sep 17 00:00:00 2001 From: fred Date: Tue, 5 Jan 1999 12:57:01 +0000 Subject: [PATCH] lilypond-1.1.21 --- Documentation/tex/lilypond-overview.doc | 389 ++++++++++++++++++++++++ 1 file changed, 389 insertions(+) create mode 100644 Documentation/tex/lilypond-overview.doc diff --git a/Documentation/tex/lilypond-overview.doc b/Documentation/tex/lilypond-overview.doc new file mode 100644 index 0000000000..f5eea5a448 --- /dev/null +++ b/Documentation/tex/lilypond-overview.doc @@ -0,0 +1,389 @@ +%-*-LaTeX-*- + +\documentclass{article} +\usepackage{a4} +\def\postMudelaExample{\setlength{\parindent}{1em}} +\title{LilyPond, a Music Typesetter} +\author{HWN} +\usepackage{musicnotes} +\usepackage{graphics} + + +\begin{document} +\maketitle + +% -*-LaTeX-*- +\section{Introduction} + +The Internet has become a popular medium for collaborative work on +information. Its success is partly due to its use of simple, text-based +formats. Examples of these formats are HTML and \LaTeX. Anyone can +produce or modify such files using nothing but a text editor, they are +easily processed with run-of-the-mill text tools, and they can be +integrated into other text-based formats. + +Software for processing this information and presenting these formats +in an elegant form is available freely (Netscape, \LaTeX, etc.). +Ubiquitousness of the software and simplicity of the formats have +revolutionised the way people publish text-based information +nowadays. + +In the field of performed music, where the presentation takes the form +of sheet music, such a revolution has not started yet. Let us review +some alternatives that have been available for transmitting sheet +music until now: +\begin{itemize} +\item MIDI\cite{midi}. This format was designed for interchanging performances + of music; one should think of it as a glorified tape recorder + format. It needs dedicated editors, since it is binary. It does + not provide enough information for producing musical scores: some of + the abstract musical content of what is performed is thrown away. + +\item PostScript\cite{Postscript}. This format is a printer control + language. Printed musical scores can be transmitted in PostScript, + but once a score is converted to PostScript, it is virtually + impossible to modify the score in a meaningful way. + +\item Formats for various notation programs. Notation programs either + work with binary formats (e.g., NIFF\cite{niff-web}), need specific + platforms (e.g., Sibelius\cite{sibelius}, Score\cite{score}), are + proprietary or non-portable tools themselves (idem), produce + inadequate output (e.g., MUP\cite{mup}), are based on graphical + content (e.g., MusixTeX\cite{musixtex1}), or limit themselves to + specific subdomains (e.g., ABC\cite{abc2mtex}). + +\item SMDL\cite{smdl-web}. This is a very rich ASCII format, that is + designed for storing many types of music. Unfortunately, there is + no implementation of a program to print music from SMDL available. + Moreover, SMDL is so verbose, that it is not suitable for human + production. + +\item TAB\cite{tablature-web}. Tab (short for tablature) is a popular + format, for interchanging music over e-mail, but it can only be used + for guitar music. +\end{itemize} + +In summary, sheet music is not published and edited on a wide scale +across the internet because no format for music +interchange exists that is: +\begin{itemize} +\item open, i.e., with publically available specifications. +\item based on ASCII, and therefore suitable for human consumption and + production. +\item rich enough for producing publication quality sheet music from + it. +\item based on musical content (unlike, for example, PostScript), and + therefore suitable for making modifications. +\item accompanied by tools for processing it that are freely available + across multiple platforms. +\end{itemize} + + +With the creation of LilyPond, we have tried to create both a +convenient format for storing sheet music, and a portable, +high-quality implementation of a compiler, that compiles the input +into a printable score. You can find a small example of LilyPond +input along with output in Figure~\ref{fig:intro-fig}. +% +\begin{figure}[htbp] + \begin{center} +\begin{mudela}[verbatim] + \score { + \notes + \type GrandStaff < + \transpose c'' { c4 c4 g4 g4 a4 a4 g2 } + { \clef "bass"; c4 c'4 + \type Staff f'4 c'4 e'4 c'4 } + > + \paper { + linewidth = -1.0\cm ; + } + } +\end{mudela} + \caption{A small example of LilyPond input} + \label{fig:intro-fig} + \end{center} +\end{figure} +% + + +The input language encodes musical events (such as notes and rests) on +the basis of their time-ordering. For example, the grammar includes +constructs that specify that notes start simultaneous and that notes +are to be played in sequence. In this encoding some context that is +present in sheet music is lost. + +The compiler reconstructs the notation from the encoded music. Its +operation comprises four different steps (see +Figure~\ref{fig:intro-steps}). + +\begin{description} +\item[Parsing] During parsing, the input is converted in a syntax tree. + +\item[Interpreting] In the \emph{interpreting} step, it is determined + which symbols have to be printed. Objects that correspond to + notation (\emph{Graphical objects}) are created from the syntax tree + in this phase. Generally speaking, for every symbol printed there is + one graphical object. These objects are incomplete: their position + and their final shape is unknown. + + The context that was lost by encoding the input in a language is + reconstructed during this conversion. +\item[Formatting] The next step is determing where symbols are to be + placed, this is called \emph{formatting}. +\item[Outputting] + Finally, all Graphical objects are outputted as PostScript or \TeX\ code. +\end{description} + +\def\staffsym{\vbox to 16pt{ + \hbox{\vrule width 1cm depth .2pt height .2pt}\nointerlineskip + \vfil + \hbox{\vrule width 1cm depth .2pt height .2pt}\nointerlineskip + \vfil + \hbox{\vrule width 1cm depth .2pt height .2pt}\nointerlineskip + \vfil + \hbox{\vrule width 1cm depth .2pt height .2pt}\nointerlineskip + \vfil + \hbox{\vrule width 1cm depth .2pt height .2pt}\nointerlineskip +}} + +\def\vspacer{\vbox to 20pt{\vss}} +\begin{figure}[h] +\def\spacedhbox#1{\hbox{\ #1\ }} +\begin{eqnarray*} + {\spacedhbox{Input}\atop \hbox{\texttt{\{c8 c8\}}}} {\spacedhbox{Parsing}\atop\longrightarrow} + {\spacedhbox{Syntax tree}\atop\spacedhbox{\textsf{Sequential(Note,Note)}}} + {\spacedhbox{Interpreting}\atop\longrightarrow}\\ + \vspacer\\ + {\spacedhbox{Graphic objects}\atop\spacedhbox{\texttrebleclef \textquarterhead\texteighthflag\textquarterhead\texteighthflag \staffsym }} + {\spacedhbox{Formatting}\atop\longrightarrow} + {\spacedhbox{Formatted objects}\atop\hbox{ + \mudela{c''8 c''8} + }}\\ +\vspacer\\ + {\spacedhbox{Outputting}\atop\longrightarrow} + {\spacedhbox{PostScript code}\atop\hbox{\texttt{\%!PS-Adobe}\ldots}} +\end{eqnarray*} + \caption{Parsing, Interpreting, Formatting and Outputting} + \label{fig:intro-steps} +\end{figure} + + +The second step, the interpretation phase of the compiler, can be +manipulated as a separate entity: the interpretation process is +composed of many separate modules, and the behaviour of the modules is +parameterised. By recombining these interpretation modules, +and changing parameter settings, the same piece of music can be +printed differently, as is shown in Figure~\ref{fig:intro-interpret}. + +This makes it easy to extend the program. Moreover, this enables the +same music to be printed in different versions, e.g., in a conductors +score and in extracted parts. + + +\begin{figure}[h] + \begin{center} + \begin{mudela} + \score { + \notes + \type GrandStaff < + \transpose c'' { c4 c4 g4 g4 a4 a4 g2 } + { \clef "bass"; c4 c'4 + \type Staff f'4 c'4 e'4 c'4 } + > + \paper { + linewidth = -1.0\cm ; + \translator { + \VoiceContext + \remove "Stem_engraver"; + } + \translator { + \StaffContext + numberOfStaffLines = 3; + } + } + } + \end{mudela} + \caption{The interpretation phase can be manipulated: the same + music as in Figure~\ref{fig:intro-fig} is interpreted + differently: three staff lines and no stems.} + \label{fig:intro-interpret} + \end{center} +\end{figure} + + + +\section{Preliminaries} + +To understand the rest of the article, it is necessary to know +something about music notation and music typography. Since both +communicate music, we will explain some characteristics of instruments +and western music that motivate some notational constructs. + +\subsection{Music} + +Music notation is meant to be read by human performers. They sing or +play instruments that can produce sounds of different pitches. These +sounds are called \emph{notes}. Additionally, the sounds can be +articulated in differents ways, e.g., staccato (short and separated) +or legato (fluently bound together). The loudness of the notes can +also be varied. Changes in loudness are called \emph{dynamics}. + +Silence is also an element of music. The musical terminology for +silence within music is \emph{rest}. + +The basic unit of pitch is the \emph{octave}. The octave corresponds +to a frequency ratio of 1:2. For example the pitch denoted by a' +(frequency: 440 hertz) is one octave lower than a'' (frequency: 880 +hertz). Various instruments have a limited \emph{pitch range}, for +example, a trumpet has a range of about 2.5 octaves. Not all +instruments have ranges in the same register: a tuba also has a range +of 2.5 octaves, but the range of the tuba is much lower. + +Musicology has a confusing mix of relative and absolute measures for +pitches: the term `octave' refers to both a difference between two +pitches (the frequency ratio of 1:2), and to a range of pitches. For +example, the term `[eengestreept] octave' refers to the pitch range +between 261.6 Hz and 523.3 Hz. + + +The octave is divided into smaller pitch steps. In modern western +music, every octave is divided into twelve approximately equidistant +pitch steps, and each step is called a \emph{semitone}. Usually, the +pitches in a musical piece come from a smaller subset of these twelve +possible pitches. This smaller subset along with the musical +functions fo the pitches is called the +\emph{tonality}\footnote{Tonality also refers to the relations between + and functions of certain pitches. Since these do not have any + impact on notation, we ignore this} of the piece. + + +The standard tonality that forms the basis of music notation +(the key of C major) is a set of seven pitches within every octave. +Each of these seven is denoted by a name. In English, these are names +are (in rising pitch) denoted by c, d, e, f, g, a and b. Pitches that +are a semitone higher or lower than one of these seven can be +represented by suffixing the name with `sharp' or `flat' +respectively (this is called an \emph{chromatic alteration}). + +A pitch therefore can be fully specified by a combination of the +octave number, the note name and a chromatic alteration. +Figure~\ref{fig:intro-pitches} shows the relation between names and +frequencies. + + + + +\begin{figure}[h] + \begin{center} + [te doen] + \end{center} + \caption{Pitches in western music. The octave number is denoted + by a superscript.} + \label{fig:intro-pitches} +\end{figure} + + +Many instruments can produce more than one note at the same time, e.g. +pianos and guitars. When more notes are played simultaneously, they +form a so-called \emph{chord}. + +The unit of duration is the \emph{beat}. When playing, the tempo is +determined by setting the number of beats per minute. In western +music, beats are often stressed in a regular pattern: for example +Waltzes have a stress pattern that is strong-weak-weak, i.e. every +note that starts on a `strong' beat is louder and has more pronounced +articulation. This stress pattern is called \emph{meter}. + +\subsection{Music notation} + +In music notation, sounds and silences are represented by symbols that +are called note and rest respectively.\footnote{These names serve a + double purpose: the same terms are used to denote the musical + concepts.} The shape of notes and rests indicates their duration +(See figure~\ref{noteshapes}) relative to the whole note. + +\begin{figure}[h] + \begin{center} +\begin{mudela} + \score { + \notes \transpose c''{ c\longa*1/4 c\breve*1/2 c1 c2 c4 c8 c16 c32 c64 } + \paper { + \translator { + \StaffContext + \remove "Staff_symbol_engraver"; + \remove "Time_signature_engraver"; + \remove "Bar_engraver"; + \remove "Clef_engraver"; + } +linewidth = -1.; + } +} +\end{mudela} +\begin{mudela} + \score { + \notes \transpose c''{ r\longa*1/4 r\breve*1/2 r1 r2 r4 r8 r16 r32 r64 } + \paper { + \translator { + \StaffContext + \remove "Staff_symbol_engraver"; + \remove "Time_signature_engraver"; + \remove "Bar_engraver"; + \remove "Clef_engraver"; + } + linewidth = -1.; + } +} +\end{mudela} + \caption{Note and rest shapes encode the length. At the top notes + are shown, at the bottom rests. From left to right a quadruple + note (\emph{longa}), double (\emph{breve}), whole, half, + quarter, eigth, sixteenth, thirtysecond and sixtyfourth. Each + note has half of the duration of its predecessor.} + \label{fig:noteshapes} +\end{center} +\end{figure} + + +Notes are printed in a grid of horizontal lines called \emph{staff} to +denote their pitch: each line represents the pitch of from the + +\subsection{Music typography} + + + + + + + +\bibliographystyle{hw-plain} +\bibliography{engraving,boeken,colorado,computer-notation,other-packages} + + + +\end{document} + +The complexity of music notation was tackled by adopting a modular +design: both the formatting system (which encodes the esthetic rules of +notation), and the interpretation system (which encodes the semantic +rules) are highly modular. + + +The difficulty in creating a format for music notation is rooted in +the fact that music is multi dimensional: each sound has its own +duration, pitch, loudness and articulation. Additionally, multiple +sounds may be played simultaneously. Because of this, there is no +obvious way to ``flatten'' music into a context-free language. + +The difficulty in creating a printing engine is rooted in the fact +that music notation complicated: it is very large graphical +``language'' with many arbitrary esthetic and semantic conventions. +Building a system that formats full fledged musical notation is a +challenge in itself, regardless of whether it is part of a compiler or +an editor. + +The fact that music and its notation are of a different nature, +implies that the conversion between input notation is non-trivial. + +In LilyPond we solved the above problem in the following way: + -- 2.39.5