% file: manual.tex % Copyright 2008 V. Bos, T. van Deursen, and S. Mauw % This file is part of the MSC Macro Package. % \documentclass[12pt,a4paper]{article} \usepackage{a4wide} \usepackage{url} \usepackage{moreverb} \usepackage{multicol} \usepackage{msc} % we allow a ragged right \setlength{\rightskip}{0pt plus 0.05\linewidth minus 0pt} \newlength{\rpwidth} \setlength{\rpwidth}{.5cm} \newlength{\rpheight} \setlength{\rpheight}{0.5\levelheight} \newcommand{\rpN}{% \psframe(-0.5\rpwidth,-\rpheight)(0.5\rpwidth,0\rpheight)% \rput[B](0\rpwidth,-0.8\rpheight){\tiny \textsc{n}}% \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}% } \newcommand{\rpNE}{% \psframe(-\rpwidth,-\rpheight)(0\rpwidth,0\rpheight)% \rput[B](-.5\rpwidth,-0.8\rpheight){\tiny \textsc{ne}}% \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}% } \newcommand{\rpE}{% \psframe(-\rpwidth,-.5\rpheight)(0\rpwidth,.5\rpheight)% \rput[B](-.5\rpwidth,-0.3\rpheight){\tiny \textsc{e}}% \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}% } \newcommand{\rpSE}{% \psframe(-\rpwidth,0\rpheight)(0\rpwidth,\rpheight)% \rput[B](-.5\rpwidth,0.2\rpheight){\tiny \textsc{se}}% \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}% } \newcommand{\rpS}{% \psframe(-.5\rpwidth,\rpheight)(.5\rpwidth,0\rpheight)% \rput[t](0\rpwidth,0.8\rpheight){\tiny \textsc{s}}% \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}% } \newcommand{\rpSW}{% \psframe(0\rpwidth,0\rpheight)(\rpwidth,\rpheight)% \rput[B](.5\rpwidth,0.2\rpheight){\tiny \textsc{sw}}% \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}% } \newcommand{\rpW}{% \psframe(0\rpwidth,-.5\rpheight)(\rpwidth,.5\rpheight)% \rput[B](.5\rpwidth,-0.3\rpheight){\tiny \textsc{w}}% \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}% } \newcommand{\rpNW}{% \psframe(0\rpwidth,-\rpheight)(\rpwidth,0\rpheight)% \rput[B](.5\rpwidth,-0.8\rpheight){\tiny \textsc{nw}}% \pscircle[fillstyle=solid,fillcolor=black](0\rpwidth,0\rpheight){.5\labeldist}% } % The following code is taken from the doc package. It defines a global % macro \bslash that produces a bslash (if present in the current font). \makeatletter {\catcode`\|=\z@ \catcode`\\=12 |gdef|bslash{\}} \makeatother \newcommand{\cmd}[1]{\texttt{\bslash #1}} \newcommand{\acro}[1]{{#1}} \newcommand{\MSC}{\acro{MSC}} \newcommand{\HMSC}{\acro{HMSC}} \newcommand{\MSCdoc}{\MSC{}doc} \newcommand{\mscpack}{\MSC{} macro package} \newcommand{\env}[1]{\texttt{#1}} \newcommand{\opt}[1]{[#1]} \newcommand{\cmdarg}[1]{\{\emph{#1}\}} \newcommand{\coordarg}[1]{\emph{#1}} \newcommand{\coordargs}[2]{(\coordarg{#1},\coordarg{#2})} \newcommand{\lnsvalue}[3]{large/normal/small value #1/#2/#3} \newenvironment{defs}{% \begin{list}{}% {\setlength{\labelwidth}{0pt}% \setlength{\labelsep}{1em}% \setlength{\leftmargin}{1em}% \setlength{\parsep}{1ex}% \setlength{\listparindent}{0pt}% \setlength{\rightmargin}{0pt}% \renewcommand{\makelabel}[1]{##1}% \raggedright% }% }{% \end{list}} \title{ A \LaTeX\ macro package for Message Sequence Charts\\{\large User Manual} } \author{ \begin{tabular}{c} \begin{tabular}{ccc} Victor Bos & Ton van Deursen & Sjouke Mauw \\ & \scriptsize Universit\'e du Luxembourg & \scriptsize Universit\'e du Luxembourg \\[-0.8ex] \scriptsize \texttt{victor.bos@ssf.fi} & \scriptsize \texttt{ton.vandeursen@uni.lu} & \scriptsize \texttt{sjouke.mauw@uni.lu} \end{tabular}\\ \end{tabular} } \date{\small Version \mscversion, last update \today\\ Describing \mscpack{} version \mscversion} \begin{document} \maketitle \begin{abstract} \noindent The \mscpack{} facilitates the \LaTeX\ user to easily include Message Sequence Charts in his texts. This document describes the design and use of the \mscpack. \end{abstract} \tableofcontents \section{New} \label{new} \paragraph{Version~1.16} solves a bug that was due to a change in syntax of the \verb+scalebox+ macro in the \verb+PSTricks+ package. The \verb+action+ and \verb+condition+ macros are extended with a starred option. The starred version of the macros automatically adjusts the size of the rectangle and hexagon based on the size of the contents. \paragraph{Version~1.13} has a reimplementation of message commands in MSC diagrams. The affected commands are: \verb+\create+, \verb+\found+, \verb+\lost+, \verb+\mess+, and \verb+\order+. The new implementation provides more control over the placement of message labels. The command \verb+\selfmesslabelpos+ has been removed. The bounding box bug has been partly solved. Now, a white \verb+\fbox+ is drawn around every (msc, mscdoc, hmsc) diagram. This makes it possible for \texttt{dvips -E} to compute the correct bounding box for the diagrams. Due to the \verb+\fbox+, each diagram is extended with 0.3pt on each side (left, top, right, and bottom). This bugfix fails if the background is not white. The xdvi program shows the white \verb+\fbox+ in black with the result that diagrams have two visible frames. This seems to be a bug of xdvi. The lines around comments (\verb+\msccomment+, Section~\ref{comments}) are changed from gray into black. The reason for this is that the gray lines became invisible after converting the document to HTML. \paragraph{Version~1.12} is a non-public version. It features a preliminary implementation of message label position control. \paragraph{Version~1.11} is a mainly a bugfix of version~1.10a, see~\cite{BM02b}. The next list shows the new features of version~1.10a compared to version 1.4. \begin{itemize} \item Support for method replies (dashed message arrows):\cmd{mess*} (Section~\ref{messages}) \item Fat instances, i.e., double line instances (Section~\ref{instances}) \item Comments (Section~\ref{comments}) \item Coregions are now special cases of regions (which includes also activation and suspension regions). The \cmd{coregionstart} and \cmd{coregionend} commands are obsolete and the \cmd{coregionbarwidth} is replaced by \cmd{regionbarwidth}. \item Gates (Section~\ref{gates}) \item High-level \MSC{}'s (Section~\ref{hmsc}) \item \cmd{inlinestart} has additional optional argument to allow for different left and right overlap (Section~\ref{inlines}) \item \MSCdoc{}s (Section~\ref{mscdoc}) \item Reference manual~\cite{BM02} \item \cmd{referencestart} has additional optional argument to allow for different left and right overlap (Section~\ref{references}) \item Regions: generalization of coregions supporting activations, suspension, and coregions (Section~\ref{regions}) \item Time measurements (Section~\ref{measurements}) \end{itemize} \section{Introduction} \label{introduction} The \MSC{} language is a visual language for the description of the interaction between different components of a system. This language is standardized by the ITU (International Telecommunication Union) in Recommendation Z.120~\cite{z120}. An introductory text on \MSC{} can be found in~\cite{RudolphGrabowskiGraubmann96}. \MSC{}s have a wide application domain, ranging from requirements specification to testing and documentation. An example of a Message Sequence Chart is in Figure~\ref{quick}. In order to support easy drawing of \MSC{}s in \LaTeX\ documents, we have developed the \mscpack. The current version of the \mscpack{} supports the following \MSC{} constructs: \MSC{} frame, instances (both single line width and double line width), messages (including self-messages and messages to the environment), actions, singular and combined timer events (set, timeout, reset, set-timeout, set-stop), lost and found messages, generalized order, conditions, coregions, activation regions, suspension regions, gates, instance creation, instance stop, time measurements, references, and inline expressions. In addition, there is support for \HMSC{}'s (high-level \MSC{}s) and \MSCdoc{}s. In this manual we explain the design and the use of the \mscpack. For a complete overview of all features, we refer to the reference manual~\cite{BM02}, which is included in the distribution under the name \verb+refman.ps+. Another way to learn how to use the \mscpack{} is to have a look at the \LaTeX{} source code of the manual and the source code of the reference manual. They are included in the distribution under the names \verb+manual.tex+ and \verb+refman.tex+, respectively. The \MSC{} constructs are simply introduced as syntactic constructs. This paper is not meant to describe their use or meaning. We list the backgrounds of the package and some design decisions in Section~\ref{background}. Section~\ref{install} contains notes on installing the package. Section~\ref{quickstart} contains an example of using the package. It allows the impatient reader to quickly start using the package. The details of using the package are explained in Section~\ref{use}. In Section~\ref{parameters} the parameters are explained which determine detailed layout of the various symbols. A large but meaningless example is given in Section~\ref{example}. \section{Background and motivation} \label{background} Several commercial and non-commercial tools are available, which support drawing or generating Message Sequence Charts. However, these tools are in general not freely available and often not flexible enough to satisfy all user's wishes with respect to the layout and graphical appearance of an \MSC{}. Therefore, people often use general drawing tools, such as {\em xfig} to draw \MSC{}s. However flexible this approach is, it takes quite some effort to produce nice \MSC{} drawings in a tool which is not dedicated to \MSC{}s. Furthermore, when drawing a number of \MSC{}s it requires some preciseness in order to obtain a consistent set of \MSC{}s. For these reasons, we have started the design of a set of \LaTeX\ macros which support the drawing of \MSC{}s. In this way, an \MSC{} can be represented in \LaTeX\ in a textual format and compiled into e.g.\ PostScript. We aimed at satisfying the following requirements and design decisions. \begin{itemize} \item The package should follow the ITU standard with respect to shape and placement of the symbols. (The current version supports the \MSC2000 standard.) \item Static and dynamic semantics are not considered. The user is allowed to violate all semantical restrictions and draw inconsistent \MSC{}s. The package only supports elementary syntactical requirements. \item The package should offer functionality at the right level of abstraction. Rather than supplying coordinates of pixels, the user should be able to express the placement of symbols in terms of {\em levels}. Nevertheless, the textual representation of \MSC{}s as defined by the ITU standard has a level of abstraction which is too high for our purposes. It lacks information about the actual positioning of the \MSC{} symbols, while we think that in our package this should be under user control. \item There should be only minimal automatic restructuring and layout of the \MSC{} (e.g.\ the relative positioning of two messages should be as defined by the user, even if the messages are not causally ordered). \item The user can customize the appearance of the \MSC{}s by manipulating an appropriate set of parameters. \end{itemize} \section{Installation, copyright and system requirements} \label{install} The \mscpack{} is still under development. The authors appreciate any comments and suggestions for improvements. The most recent version of the package can be downloaded from \url{http://satoss.uni.lu/mscpackage/}. The \mscpack{} has a \emph{LaTeX Project Public License} (LPPL), see~\url{http://www.latex-project.org/lppl.txt}: {\small \verbatiminput{COPYRIGHT} } As such, it is free of charge and can be freely distributed. Furthermore, it is allowed to make modifications to the package, provided that modified versions get different names. The authors accept no liability with respect to the functioning of the package. The \mscpack{} runs with \LaTeXe. It has been tested with \LaTeXe\ version dated 1998/06/01 using \TeX\ version 3.14159. The following additional packages are required: \textsf{pstricks}, \textsf{calc}, \textsf{ifthen}, and \textsf{color}. These packages are in general part of the standard \LaTeXe\ distribution. These additional packages can be obtained from the {\em ctan} database for \LaTeX\, e.g.\ via the following URL: \url{http://www.tex.ac.uk/}. The \textsf{pstricks} package is described in~\cite[Chapter~4]{GSM97}. The generated output can only be previewed with recent previewing software (e.g.\ xdvi version 20c). It may be needed to update all \LaTeX\ related software to a more recent version in order to smoothly work with the \mscpack. The \mscpack{} can be installed easily. Just put the file \verb+msc.sty+ in a directory which is searched by \LaTeX{} for style files. The set of directories actually searched depends on the \TeX\ installation, but often the {\em current directory} is included. UNIX users may have to set the environment variable \texttt{\$TEXINPUTS} to an appropriate value. For more details on this topic consult documentation of your \TeX\ installation. %The following text is currently not applicable -sm % %A problem may occur when using more packages than the \MSC{} macro %package in your \LaTeX\ document. This happens, e.g.\ when using the %{\em epsfig} package. These problems are due to the combination of %several packages which are required (but not provided) by the \MSC{} %macro package. The solution is to change the order of the %\verb+usepackage+ clauses. \section{Quick start} \label{quickstart} The \mscpack{} is easy to use. Below is an example of the use of the package and Figure~\ref{quick} shows the generated \MSC{}. {\small \begin{verbatim} \documentclass{article} \usepackage{msc} \begin{document} \begin{msc}{Example} \declinst{usr}{User}{} \declinst{m1}{Machine 1}{control} \declinst{m2}{Machine 2}{drill} \declinst{m3}{Machine 3}{test} \mess{startm1}{usr}{m1} \nextlevel \mess{startm2}{m1}{m2} \nextlevel \mess{continue}{m2}{m3} \mess{log}{m1}{envleft} \nextlevel \mess{output}{m3}{usr}[2] \nextlevel \mess{free}{m1}{usr} \nextlevel \end{msc} \end{document} \end{verbatim} } \begin{figure}[htb] \begin{center} \begin{msc}{Example} \declinst{usr}{User}{} \declinst{m1}{Machine 1}{control} \declinst{m2}{Machine 2}{drill} \declinst{m3}{Machine 3}{test} \mess{startm1}{usr}{m1} \nextlevel \mess{startm2}{m1}{m2} \nextlevel \mess{continue}{m2}{m3} \mess{log}{m1}{envleft} \nextlevel \mess{output}{m3}{usr}[2] \nextlevel \mess{free}{m1}{usr} \nextlevel \end{msc} \end{center} \caption{The generated \MSC{}} \label{quick} \end{figure} The \mscpack{} is activated by the clause \verb+\usepackage{msc}+. This package contains, among others, a definition of the environment \verb+msc+. This environment is used to draw \MSC{}s. The \MSC{} definition is surrounded by the clauses \verb+\begin{msc}{Example}+ and \verb+\end{msc}+. The name of the \MSC{}, {\tt Example}, is displayed in the upper-left corner of the \MSC{}. The next four lines define the \emph{instances}: \verb+\declinst{m1}{Machine 1}{control}+ defines an instance with \emph{nickname} \verb+m1+ and a description consisting of two parts, namely, \verb+Machine 1+ and \verb+control+. The nickname is used in all subsequent references to this instance. The first part of the description is drawn above the rectangular instance head symbol, and the second part of the description is drawn inside the instance head symbol. The following lines contain the definitions of the messages. Every message has a source and a destination instance. The clause \verb+\mess{startm1}{usr}{m1}+ defines a message with name {\tt startm1}, which goes from instance {\tt usr} to instance {\tt m1}. In order to control the vertical placement of the messages, the \MSC{} is divided into levels. At every level, any number of messages may start. The vertical position of the end point of a message is determined by the optional fourth argument of the message definition, as in the clause \verb+\mess{output}{m2}{user}[2]+. This argument is the vertical offset (in number of levels) between the start point of the message (i.e.\ the current level) and its end point. If the value is 0 the message is drawn horizontally. A negative offset means that the arrow has an upward slope. The clause \verb+\nextlevel+ is used to advance to the next level. \section{Use of the \mscpack} \label{use} \subsection{The \MSC{} frame} \label{mscframe} The \verb+msc+ environment is used for making \MSC{} definitions. Thus, such a definition looks as follows. \begin{verbatim} \begin{msc}[headerpos]{mscname} ...definition of the MSC... \end{msc} \end{verbatim} This draws the frame and the header of the \MSC{}. The argument \verb+mscname+ is the name of the \MSC{}. The header of an \MSC{} is formed from the keyword \verb+msc+, followed by the \verb+mscname+. Positioning of this header is controlled by the optional argument \verb+headerpos+. This argument can have values \verb+l+ (for a left aligned header), \verb+c+ (for a centered header) and \verb+r+ (for a right aligned header). The default value of \verb+headerpos+ is \verb+l+. The size of the \MSC{} frame is determined vertically by the number of levels occurring in the \MSC{} (see Section~\ref{levels}) and horizontally by the number of instances (see Section~\ref{instances}). The parameter \verb+\topnamedist+ controls the distance between the top of the \MSC{} frame and the header (see Section~\ref{parameters}). The parameter \verb+\leftnamedist+ controls the distance between the left of the \MSC{} frame and the header if the \verb+headerpos+ is \verb+l+ and it controls the distance between the right of the \MSC{} frame and the header if \verb+headerpos+ is \verb+r+ (see Section~\ref{parameters}). \subsection{Levels} \label{levels} An \MSC{} is vertically divided in {\em levels}. All events in an \MSC{} are attached to a certain level, or stretch out over several levels. Any number of events can be drawn at a certain level. An event will always be drawn (or started) at the current level, unless a level offset is specified (see e.g.\ the \verb+\mess+ command in Section~\ref{messages}). The level offset is an integer number, which denotes at which level, relative to the current level, an event should be drawn. Drawing starts at level 0. The following command is used to advance to the next level. \begin{verbatim} \nextlevel[leveloffset] \end{verbatim} The \verb+leveloffset+ is an integer value which denotes the number of levels to advance. By default, the value of \verb+leveloffset+ is 1, which means drawing continues at the next level. Setting \verb+leveloffset+ to a negative value may result in unexpected drawings, however, see the \emph{Tricks} section in the reference manual~\cite{BM02}. There are three parameters which control the size of the levels (see Section~\ref{parameters}). These are \verb+\firstlevelheight+ (the distance between the instance start symbol and the first level), \verb+\levelheight+ (the distance between two consecutive levels), and \verb+\lastlevelheight+ (the distance between the last level and the instance end symbol). Figure~\ref{parametersfig} on page~\pageref{parametersfig} shows all lengths of the \mscpack. \subsection{Instances} \label{instances} All instances have to be declared before they can be used. An instance consists of an instance head symbol with an associated name, an instance axis and an instance end symbol. Normal instances have a single line axis. Fat instances have a double line axis. The order of the instance declarations determines the order in which the instances occur in the drawing. An instance is declared with the following command. \begin{verbatim} \declinst(*){nickname}{instancenameabove}{instancenamewithin} \end{verbatim} The starred version produces a fat instance. The \verb+nickname+ is used for referring to this instance in the rest of the \MSC{} definition. The \verb+instancenameabove+ is put above the instance head symbol. The \verb+instancenamewithin+ is put inside the instance head symbol. Several parameters allow the user to customize the shape and positioning of instances (see Section~\ref{parameters}). These are \verb+\topheaddist+ (the distance between the top of the \MSC{} and the instance head symbol), \verb+\instheadheight+ (the height of the instance head symbol), \verb+\instfootheight+ (the height of the instance foot symbol), \verb+\bottomfootdist+ (the distance between the instance foot symbol and the bottom of the \MSC{} frame), \verb+\instwidth+ (the width of the instance head and foot symbols), \verb+\instdist+ (the distance between two instance axes), \verb+\envinstdist+ (the distance between the edge of the \MSC{} and the first/last instance axis), and \verb+\labeldist+ (the distance between the instance head symbol and the part of the instance name drawn above the head symbol). The command \verb+\setfootcolor{color}+ sets the fill color of the footer symbol. Valid color values are, e.g., \texttt{black} (default), \texttt{white}, and \texttt{gray}. The following \MSC{} shows the declaration of an \MSC{} with three instances. The first and the last are normal instances (one line axis) whereas the second is a fat instance (double line axis). The second line, \verb+\setmscvalues{small}+, indicates that the small drawing style should be used (see Section~\ref{parameters}). \medskip \begin{minipage}[c]{0.4\linewidth} \begin{msc}[l]{instances} \setmscvalues{small} \declinst{i}{above}{within} \declinst*{j}{}{j} \declinst{k}{k}{} \end{msc} \end{minipage} % \begin{minipage}[c]{0.5\linewidth} {\small \begin{verbatim} \begin{msc}{instances} \setmscvalues{small} \declinst{i}{above}{within} \declinst*{j}{}{j} \declinst{k}{k}{} \end{msc} \end{verbatim} } \end{minipage} \subsection{Messages} \label{messages} A message is denoted by an arrow from the sending instance to the receiving instance. The instances are referred to by their nicknames. A message is defined with the following command. \begin{verbatim} \mess(*)[pos]{name}[labelpos]{sender}[placement]{receiver}[leveloffset] \end{verbatim} The \verb+name+ of the message may be any string. The \mscpack{} processes the \verb+name+ argument in LR-mode, see~\cite[page~36]{Lam94}. This means that the string will consist of one line. To generate multi-line message names, use the standard \cmd{parbox} command, see the \emph{Tricks} section in the reference manual~\cite{BM02}. By default, the name of a message label is drawn above the center of the arrow, but the optional parameters \verb+pos+, \verb+labelpos+, and \verb+placement+ influence the actual location, as described below. The arrow starts at the current level at the sending instance. The arrow ends at the current level plus the \verb+leveloffset+, at the receiving instance. The \verb+leveloffset+ is an optional integer argument with default value 0. The \verb+sender+ and \verb+receiver+ should be the nicknames of declared instances. In case the sending and the receiving instance are the same, the message is a \emph{self message}. A self message is drawn as a polyline connecting the instance axis to itself. The starred version of the command, \verb+\mess*+, produces the same result as \verb+\mess+, except that the arrow is drawn with a dashed line. This can be used to draw a {\em method reply} (see~\cite{z120}). As mentioned above, placement of the message and its label is controlled by the optional parameters \verb+pos+, \verb+labelpos+, and \verb+placement+. In case of a self message, \verb+pos+ denotes the position of the arrow with respect to the instance axis. Valid values are \verb+l+ (left) and \verb+r+ (right). The default value is \verb+l+. In case of a non-self message, the \verb+pos+ parameter is ignored. Whereas the \verb+pos+ parameter defines the position of the arrow symbol with respect to the instance axis, the \verb+labelpos+ parameter defines the position of the message label with respect to the message arrow. In case of a self message, valid values for \verb+labelpos+ are \verb+l+ (left) and~\verb+r+ (right). The default value is equal to the, possibly user defined, value of the \verb+pos+ parameter. In case of a non-self message, valid values for \verb+labelpos+ are \verb+t+ (on top) and~\verb+b+ (below). The default value is~\verb+t+. Finally, the \verb+placement+ parameter defines the relative distance of the message label to the beginning of the message. Valid values are real numbers in the closed interval $[0,1]$. The default value is~$0.5$. While drawing a message, the \mscpack{} computes the coordinates of the message label using \verb+placement+ and the length and coordinates of the arrow. It then computes a \emph{reference point} for the message label and places it on the coordinates just computed. Figures \ref{fig:refpoints} (page~\pageref{fig:refpoints}) and~\ref{fig:refpoints:B} (page~\pageref{fig:refpoints:B}) schematically show the reference points for message labels. In the first figure, the labels are located at the default position. In the second figure, all labels are shifted along the arrow by setting $\verb+placement+ = 0.9$. The \verb+\lost+ and \verb+\found+ commands (Section~\ref{lostfound}) and the \verb+\create+ (Section~\ref{createstop}) command use the same method to determine reference points and message label locations. Note that the boxes with the location of the reference points are not generated by the \LaTeX{} code given in Figures \ref{fig:refpoints} and~\ref{fig:refpoints:B}; we enriched the \LaTeX{} code with some extra \textsf{pstricks} code (see \LaTeX{} source code of this document). In addition to label position control, there are three ways to control the shape of messages (see Section~\ref{parameters}). These are: \verb+\selfmesswidth+ (a parameter to specify the width of the polyline used for drawing self-messages), \verb+\labeldist+ (a parameter to specify the distance between the label of a message and the message arrow), and \verb+\messarrowscale{size}+ (a command to set the size of the arrow head of a message). \verb+size+ should be positive real number. Messages to or from the environment (i.e.\ the left or the right side of the \MSC{} frame) can be specified by setting the sender or the receiver argument to one of the values \verb+envleft+ or \verb+envright+. (Note: Since instances and environments are treated equally in the implementation, at every position where the nickname of an instance is required, also \verb+envleft+ and \verb+envright+ are allowed.) The following \MSC{} shows an example of the use of messages. In this sample \MSC{} and the following \MSC{}s in this section we will not list the complete textual representations of the \MSC{}s. For brevity we omit the environment call and the declarations of the instances. Note the final \verb+\nextlevel+ command which is needed to make the instance axis long enough to receive message \verb+a+. \medskip \begin{minipage}[c]{0.4\linewidth} \begin{msc}{messages} \setmscvalues{small} \setlength{\topheaddist}{0.8cm} \declinst{i}{}{i} \declinst{j}{}{j} \declinst{k}{}{k} \mess{a}{j}{i}[3] \mess{self}{i}{i} \nextlevel \mess*{b}{j}{k} \mess[b]{c}{k}{envright} \nextlevel \mess{d}{k}[.6]{i} \nextlevel \end{msc} \end{minipage} % \begin{minipage}[c]{0.5\linewidth} {\small \begin{verbatim} \mess{a}{j}{i}[3] \mess{self}{i}{i} \nextlevel \mess*{b}{j}{k} \mess[b]{c}{k}{envright} \nextlevel \mess{d}{k}[.6]{i} \nextlevel \end{verbatim} } \end{minipage} \begin{figure}[htb] \begin{minipage}{\linewidth} \setmscvalues{small} \begin{multicols}{2} \begin{msc}{Label reference points} \declinst{m0}{I0}{} \declinst{m1}{I1}{} \declinst{m2}{I2}{} \nextlevel \mess{\rpS}{m0}{m1} \nextlevel \mess{\rpN}[b]{m1}{m2} \nextlevel[2] \mess{\rpS}{m1}{m0} \nextlevel \mess{\rpN}[b]{m2}{m1} \nextlevel[2] \mess{\rpE}{m0}{m0}[2] \mess[r]{\rpW}{m2}{m2}[2] \nextlevel[4] \mess{\rpW}[r]{m0}{m0}[2] \mess[r]{\rpE}[l]{m2}{m2}[2] \nextlevel[6] \mess{\rpE}{m0}{m0}[-2] \mess[r]{\rpW}{m2}{m2}[-2] \nextlevel[4] \mess{\rpW}[r]{m0}{m0}[-2] \mess[r]{\rpE}[l]{m2}{m2}[-2] \nextlevel[2] \mess{\rpSW}{m0}{m1}[2] \mess{\rpNE}[b]{m1}{m2}[2] \nextlevel[6] \mess{\rpSW}{m1}{m0}[-2] \mess{\rpNE}[b]{m2}{m1}[-2] \nextlevel[2] \mess{\rpSE}{m1}{m0}[2] \mess{\rpNW}[b]{m2}{m1}[2] \nextlevel[6] \mess{\rpSE}{m0}{m1}[-2] \mess{\rpNW}[b]{m1}{m2}[-2] \nextlevel[2] \end{msc} \bigskip \scriptsize \begin{verbatim} \begin{msc}{Label reference points} \declinst{m0}{I0}{} \declinst{m1}{I1}{} \declinst{m2}{I2}{} \nextlevel \mess{S}{m0}{m1} \nextlevel \mess{N}[b]{m1}{m2} \nextlevel[2] \mess{S}{m1}{m0} \nextlevel \mess{N}[b]{m2}{m1} \nextlevel[2] \mess{E}{m0}{m0}[2] \mess[r]{W}{m2}{m2}[2] \nextlevel[4] \mess{W}[r]{m0}{m0}[2] \mess[r]{E}[l]{m2}{m2}[2] \nextlevel[6] \mess{E}{m0}{m0}[-2] \mess[r]{W}{m2}{m2}[-2] \nextlevel[4] \mess{W}[r]{m0}{m0}[-2] \mess[r]{E}[l]{m2}{m2}[-2] \nextlevel[2] \mess{SW}{m0}{m1}[2] \mess{NE}[b]{m1}{m2}[2] \nextlevel[6] \mess{SW}{m1}{m0}[-2] \mess{NE}[b]{m2}{m1}[-2] \nextlevel[2] \mess{SE}{m1}{m0}[2] \mess{NW}[b]{m2}{m1}[2] \nextlevel[6] \mess{SE}{m0}{m1}[-2] \mess{NW}[b]{m1}{m2}[-2] \nextlevel[2] \end{msc} \end{verbatim} \end{multicols} \end{minipage} \caption{Reference points of message labels} \label{fig:refpoints} \end{figure} \begin{figure}[htb] \begin{minipage}{\linewidth} \setmscvalues{small} \begin{multicols}{2} \begin{msc}{Label reference points (2)} \declinst{m0}{I0}{} \declinst{m1}{I1}{} \declinst{m2}{I2}{} \nextlevel \mess{\rpS}{m0}[.9]{m1} \nextlevel \mess{\rpN}[b]{m1}[.9]{m2} \nextlevel[2] \mess{\rpS}{m1}[.9]{m0} \nextlevel \mess{\rpN}[b]{m2}{m1} \nextlevel[2] \mess{\rpE}{m0}[.9]{m0}[2] \mess[r]{\rpW}{m2}[.9]{m2}[2] \nextlevel[4] \mess{\rpW}[r]{m0}[.9]{m0}[2] \mess[r]{\rpE}[l]{m2}[.9]{m2}[2] \nextlevel[6] \mess{\rpE}{m0}[.9]{m0}[-2] \mess[r]{\rpW}{m2}[.9]{m2}[-2] \nextlevel[4] \mess{\rpW}[r]{m0}[.9]{m0}[-2] \mess[r]{\rpE}[l]{m2}[.9]{m2}[-2] \nextlevel[2] \mess{\rpSW}{m0}[.9]{m1}[2] \mess{\rpNE}[b]{m1}[.9]{m2}[2] \nextlevel[6] \mess{\rpSW}{m1}[.9]{m0}[-2] \mess{\rpNE}[b]{m2}[.9]{m1}[-2] \nextlevel[2] \mess{\rpSE}{m1}[.9]{m0}[2] \mess{\rpNW}[b]{m2}[.9]{m1}[2] \nextlevel[6] \mess{\rpSE}{m0}[.9]{m1}[-2] \mess{\rpNW}[b]{m1}[.9]{m2}[-2] \nextlevel[2] \end{msc} \bigskip \scriptsize \begin{verbatim} \begin{msc}{Label reference points (2)} \declinst{m0}{I0}{} \declinst{m1}{I1}{} \declinst{m2}{I2}{} \nextlevel \mess{S}{m0}[.9]{m1} \nextlevel \mess{N}[b]{m1}[.9]{m2} \nextlevel[2] \mess{S}{m1}[.9]{m0} \nextlevel \mess{N}[b]{m2}{m1} \nextlevel[2] \mess{E}{m0}[.9]{m0}[2] \mess[r]{W}{m2}[.9]{m2}[2] \nextlevel[4] \mess{W}[r]{m0}[.9]{m0}[2] \mess[r]{E}[l]{m2}[.9]{m2}[2] \nextlevel[6] \mess{E}{m0}[.9]{m0}[-2] \mess[r]{W}{m2}[.9]{m2}[-2] \nextlevel[4] \mess{W}[r]{m0}[.9]{m0}[-2] \mess[r]{E}[l]{m2}[.9]{m2}[-2] \nextlevel[2] \mess{SW}{m0}[.9]{m1}[2] \mess{NE}[b]{m1}[.9]{m2}[2] \nextlevel[6] \mess{SW}{m1}[.9]{m0}[-2] \mess{NE}[b]{m2}[.9]{m1}[-2] \nextlevel[2] \mess{SE}{m1}[.9]{m0}[2] \mess{NW}[b]{m2}[.9]{m1}[2] \nextlevel[6] \mess{SE}{m0}[.9]{m1}[-2] \mess{NW}[b]{m1}[.9]{m2}[-2] \nextlevel[2] \end{msc} \end{verbatim} \end{multicols} \end{minipage} \caption{Reference points of shifted message labels} \label{fig:refpoints:B} \end{figure} \subsection{Comments} \label{comments} Comments are additional texts to clarify (events on) an instance. The following command can be used to add comments to an \MSC{} diagram. \begin{verbatim} \msccomment[position]{text}{instname} \end{verbatim} The \verb|instname| parameter defines the instance to which the comment is attached. The text of the comment is specified by the \verb|text| parameter and is processed in LR-mode. The \verb|position| parameter defines the horizontal position of the comment relative to its instance. Valid values of \verb|position| are \verb|l| (left), \verb|r| (right), or any \LaTeX{} length. Its default value is~\verb|l|. If the value of \verb|position| is \verb|l| (or~\verb|r|), the comment will be placed \verb|\msccommentdist| units to the left (or right) of the \verb|instname| instance. If \verb|position| is a \LaTeX{} length, the comment will be placed \verb|position| units from the \verb|instname| instance. A negative length puts the comment to the left and a positive length puts the comment to the right of the instance. The following diagram shows how to use comments. In this diagram, the distance between the frame and the instances (\verb|\envinstdist|) is doubled in order to fit the comments inside the frame. \medskip \begin{minipage}[c]{0.4\linewidth} \setmscvalues{small} \begin{msc}{comments} \setlength{\envinstdist}{2\envinstdist} \declinst{i}{}{i} \declinst{j}{}{j} \mess{a}{i}{j}[2] \msccomment{start}{i} \nextlevel[2] \msccomment[r]{end}{j} \nextlevel \end{msc} \end{minipage} % \begin{minipage}[c]{0.54\linewidth} {\small \begin{verbatim} \setlength{\envinstdist}{2\envinstdist} \declinst{i}{}{i} \declinst{j}{}{j} \mess{a}{i}{j}[2] \msccomment{start}{i} \nextlevel[2] \msccomment[r]{end}{j} \nextlevel \end{verbatim} } \end{minipage} \subsection{Actions} \label{actions} An instance can perform an action, which is denoted by a rectangle. \begin{verbatim} \action(*){name}{instance} \end{verbatim} The action is attached at the current level to the \verb+instance+. The \verb+name+ is centered inside the action symbol and is processed in LR-mode. The following parameters determine the detailed drawing of the action symbol (see Section~\ref{parameters}): \verb+\actionwidth+ (the width of the action symbol), and \verb+\actionheight+ (the height of the action symbol). The starred version of the command, \verb+\action*+, produces the same result as \verb+\action+, except that the height and width of the action symbol are adjusted to fit the contents of the rectangle. The next example shows that after an action often a multiple level increment is needed to obtain nice pictures. \medskip \begin{minipage}[c]{0.4\linewidth} \begin{msc}{action} \setmscvalues{small} %\setlength{\topheaddist}{0.8cm} \declinst{i}{}{i} \declinst{j}{}{j} \mess{a}{j}{i} \nextlevel \action{doit}{i} \nextlevel[2] \mess{b}{i}{j} \end{msc} \end{minipage} % \begin{minipage}[c]{0.5\linewidth} {\small \begin{verbatim} \mess{a}{j}{i} \nextlevel \action{doit}{i} \nextlevel[2] \mess{b}{i}{j} \end{verbatim} } \end{minipage} \subsection{Timers} \label{timers} There are five commands to draw timer events. \begin{verbatim} \settimer[placement]{name}{instance} \timeout[placement]{name}{instance} \stoptimer[placement]{name}{instance} \settimeout[placement]{name}{instance}[offset] \setstoptimer[placement]{name}{instance}[offset] \end{verbatim} Setting of a timer is drawn as a line connecting the \verb+instance+ to the {\em hour glass} symbol. The \verb+name+ is put near this symbol. A time-out is represented by an arrow from an {\em hour glass} symbol to the \verb+instance+. Stopping a timer is drawn as a line connecting the \verb+instance+ with the timer stop symbol (denoted by a cross). The command \verb+\settimeout+ is a combination of the setting of a timer and a time out. The \verb+offset+ denotes the number of levels between the two events. The default value for \verb+offset+ is 2. Likewise, \verb+\setstoptimer+ is a combination of the setting of a timer and stopping a timer. The optional argument \verb+placement+ can have values \verb+l+ (meaning that the timer is drawn left of the instance axis) and \verb+r+ (meaning that the timer is drawn right of the instance axis). By default it is drawn at the left side of the instance. Several parameters can be used to control the detailed layout of timer symbols (see Section~\ref{parameters}): \verb+\timerwidth+ (the width of the hour glass and time out symbols), \verb+\selfmesswidth+ (the length of the arm between the symbol and the instance axis), and \verb+\labeldist+ (the distance between the name and the timersymbol). Furthermore, the size of the arrow head can be controlled with the command \verb+\messarrowscale{size}+. The various timer symbols are shown in the following example. \medskip \begin{minipage}[c]{0.4\linewidth} \begin{msc}{timers} \setmscvalues{small} \setlength{\topheaddist}{0.8cm} \declinst{i}{}{i} \declinst{j}{}{j} \declinst{k}{}{k} \settimer{T,50}{j} \setstoptimer[r]{V}{k}[6] \nextlevel[2] \timeout{T}{j} \settimeout{U}{i} \nextlevel[2] \settimer[r]{T,20}{j} \nextlevel[2] \stoptimer[r]{T}{j} \end{msc} \end{minipage} % \begin{minipage}[c]{0.5\linewidth} {\small \begin{verbatim} \settimer{T,50}{j} \setstoptimer[r]{V}{k}[6] \nextlevel[2] \timeout{T}{j} \settimeout{U}{i} \nextlevel[2] \settimer[r]{T,20}{j} \nextlevel[2] \stoptimer[r]{T}{j} \end{verbatim} } \end{minipage} \subsection{Time measurements} \label{measurements} There are several commands to add time measurements to an \MSC{}. \begin{verbatim} \mscmark[placement]{name}{instance} \measure(*)[placement]{name}{instance1}{instance2}[offset] \measurestart(*)[placement]{name}{instance}{gate} \measureend(*)[placement]{name}{instance}{gate} \end{verbatim} An absolute time stamp is attached to an event on an \verb+instance+ with the command \verb+mscmark+. The \verb+name+ is the text attached to the mark symbol, which is a dashed polyline. The position of the mark symbol relative to the marked event is determined by the \verb+placement+. (\verb+tl+ means top-left, \verb+tr+ means top-right, \verb+bl+ means bottom-left, and \verb+br+ means bottom-right). A \verb+\measure+ connects two events from \verb+instance1+ and \verb+instance2+. The first event is at the current level. The second event is \verb+offset+ levels lower than the first event. The \verb+name+ is attached to the measure symbol. The measure symbol can be placed at the left or at the right of \verb+instance1+. This is controlled by the optional argument \verb+placement+, which can have values \verb+l+ and \verb+r+. In case the two events are far apart, the measure may be split in two parts. The first part is drawn with the \verb+\measurestart+ command and the second part with the \verb+\measureend+ command. The points where these two parts should be connected are drawn by a small circle, to which the text \verb+gate+ is attached. There are two equivalent forms of the measurement symbol. The first form, where the arrow heads are at the inside of the measured interval, is the default form. The second form, where the arrow heads are at the outside of the measured interval, is obtained by the commands \verb+\measure*+, \verb+\measurestart*+, and \verb+\measureend*+. Several parameters can be used to control the detailed layout of the time measurement symbols (see Section~\ref{parameters}): \verb+\labeldist+ (a parameter to specify the distance between the label of a measurement and the measurement symbol), \verb+\messarrowscale{size}+ (a command to set the size of the arrow head), \verb+\selfmesswidth+ (specifies the width of the measurement symbols). The following example illustrates marks and measurements in an \MSC{}. In order to include the marks inside the frame of the diagram, the distance between the frame and the instances (called \verb+\envinstdist+) is increased (before the instances are declared). \medskip \begin{minipage}[c]{0.5\linewidth} \begin{msc}{Time measurements} \setmscvalues{small} \setlength{\envinstdist} {2\envinstdist} \declinst{i}{}{i} \declinst{j}{}{j} \declinst{k}{}{k} \mess{m1}{i}{j}[1] \mscmark{t=0.0}{i} \measure{0.6}{i}{j}[4] \nextlevel \mscmark[tr]{t=0.3}{j} \nextlevel[3] \mess{m2}{j}{k} \measurestart*[r]{0.2}{k}{g} \nextlevel[6] \mess{m3}{k}{i} \mscmark[bl]{t=1.0}{i} \measureend*[r]{0.2}{k}{g} \nextlevel \end{msc} \end{minipage} % \begin{minipage}[c]{0.44\linewidth} {\small \begin{verbatim} \setlength{\envinstdist} {2\envinstdist} \declinst{i}{}{i} \declinst{j}{}{j} \declinst{k}{}{k} \mess{m1}{i}{j}[1] \mscmark{t=0.0}{i} \measure{0.6}{i}{j}[4] \nextlevel \mscmark[tr]{t=0.3}{j} \nextlevel[3] \mess{m2}{j}{k} \measurestart*[r]{0.2}{k}{g} \nextlevel[6] \mess{m3}{k}{i} \mscmark[bl]{t=1.0}{i} \measureend*[r]{0.2}{k}{g} \nextlevel \end{verbatim} } \end{minipage} \subsection{Lost and found messages} \label{lostfound} A lost message is denoted by an arrow starting at an instance and ending at a filled circle. A found message is denoted by an arrow starting at an open circle and ending at an instance. The following commands are used to define lost and found messages. \begin{verbatim} \lost[pos]{name}[labelpos]{gate}{instance}[placement] \found[pos]{name}[labelpos]{gate}{instance}[placement] \end{verbatim} The argument \verb+instance+ determines the instance to which the arrow is attached. The \verb+name+ of the message is put above the message arrow. The \verb+gate+ is a text associated to the circle. The optional arguments \verb+pos+, \verb+labelpos+, and \verb+placement+ have the same function as in the \verb+\mess+ command (Section~\ref{messages}). That is, \verb+pos+ controls the placement of the lost or or found message with respect to the instance axis. Valid values are \verb+l+ (left) and~\verb+r+ (right). The default value is~\verb+l+. The optional parameters \verb+labelpos+ and \verb+placement+ control the placement of \verb+name+ with respect to the message arrow. Valid values for \verb+labelpos+ are \verb+t+ (on top) and~\verb+b+ (below). The default value is~\verb+t+. Valid values for \verb+placement+ are real numbers in the closed interval $[0,1]$ and denote the relative distance of the message label \verb+name+ to the beginning of the arrow. The default value for \verb+placement+ is~$0.5$. Several parameters can be used to control the detailed layout of lost and found messages (see Section~\ref{parameters}): \verb+\lostsymbolradius+ (the radius of the circle), \verb+\selfmesswidth+ (the length of the arrow), and \verb+\labeldist+ (the distance between the name and the arrow). Furthermore, the size of the arrow head can be controlled with the command \verb+\messarrowscale{size}+. The following example shows a found and a lost message. \medskip \begin{minipage}[c]{0.4\linewidth} \begin{msc}{lost and found} \setmscvalues{small} \setlength{\topheaddist}{0.8cm} \declinst{i}{}{i} \declinst{j}{}{j} \found{m}{g}{i} \nextlevel \mess{p}{i}{j} \nextlevel \lost[r]{n}{}{j} \end{msc} \end{minipage} % \begin{minipage}[c]{0.5\linewidth} {\small \begin{verbatim} \found{m}{g}{i} \nextlevel \mess{p}{i}{j} \nextlevel \lost[r]{n}{}{j} \end{verbatim} } \end{minipage} \subsection{Conditions} \label{conditions} A condition is denoted by a hexagon. It is used to express that the system has entered a certain state. A condition relates to a number of instances. All conditions which take part in the condition are covered by the condition symbol. The other instances are drawn through the condition symbol. The following command is used to draw a condition. \begin{verbatim} \condition{text}{instancelist} \end{verbatim} The \verb+text+ is placed in the center of the condition. The \verb+instancelist+ expresses which instances take part in the condition. It is a list of nicknames of instances, separated by commas. Take care not to add extra white space around the nicknames, since this is considered part of the nickname in \LaTeX. The order in which the instances are listed is immaterial. There are two parameters which control the shape of the condition symbol (see Section~\ref{parameters}): \verb+\conditionheight+ (the height of the condition symbol), and \verb+\conditionoverlap+ (the width of the part of the condition symbol which extends over the rightmost/leftmost contained instance axis). The starred version of the command, \verb+\condition*+, produces the same result as \verb+\condition+, except that the height and width of the condition symbol are adjusted to fit the contents of the hexagon. The following example contains some conditions. \medskip \begin{minipage}[c]{0.4\linewidth} \begin{msc}{conditions} \setmscvalues{small} \setlength{\topheaddist}{0.8cm} \declinst{i}{}{i} \declinst{j}{}{j} \declinst{k}{}{k} \condition{some condition}{i,k} \nextlevel[3] \mess{m}{i}{j} \action{a}{k} \nextlevel \condition{C}{i} \nextlevel[2] \condition{A, B, C}{i,j,k} \nextlevel[2] \end{msc} \end{minipage} % \begin{minipage}[c]{0.5\linewidth} {\small \begin{verbatim} \condition{some condition}{i,k} \nextlevel[3] \mess{m}{i}{j} \action{a}{k} \nextlevel \condition{C}{i} \nextlevel[2] \condition{A, B, C}{i,j,k} \nextlevel[2] \end{verbatim} } \end{minipage} \subsection{Generalized ordering} \label{ordering} A generalized order is treated much like a regular message (see Section~\ref{messages}). There are three differences: a generalized order is drawn with a dotted line, it has no label, and the arrow head is in the middle of the line. A generalized order is defined with the following command. \begin{verbatim} \order[pos]{sender}{receiver}[leveloffset] \end{verbatim} The \verb+sender+ and \verb+receiver+ are the nicknames of the instances which are connected by the generalized ordering symbol. At the \verb+receiver+ instance, the generalized ordering symbol ends at the current level plus the \verb+leveloffset+. The \verb+leveloffset+ is an optional integer value, with default 0. In case \verb+sender+ and \verb+receiver+ denote the same instance, the order is a \emph{self order}. The placement of the order arrow of a self order is controlled by the optional argument \verb+pos+. It can have values \verb+l+ (meaning that the ordering symbol is drawn left of the instance axis) and \verb+r+ (meaning that the ordering symbol is drawn right of the instance axis). By default it is drawn at the left side of the instance. For non-self orders, the \verb+pos+ argument is ignored. Additionally, there are two ways to control the shape of the generalized ordering symbol (see Section~\ref{parameters}). These are: \verb+\selfmesswidth+ (a parameter to specify the width of the polyline used for drawing orderings on a single instance axis). and \verb+\messarrowscale{size}+ (a command to set the size of the arrow head in the ordering symbol). Orderings to or from the environment (i.e.\ the left or the right side of the \MSC{} frame) can be specified by setting the sender or the receiver argument to the value \verb+envleft+ or \verb+envright+. An example of a generalized order is given in the following diagram. \medskip \begin{minipage}[c]{0.4\linewidth} \begin{msc}{generalized order} \setmscvalues{normal} \setlength{\topheaddist}{0.8cm} \declinst{i}{}{i} \declinst{j}{}{j} \mess{m}{envleft}{i} \order{i}{j}[1] \nextlevel \mess{k}{j}{envright} \nextlevel \end{msc} \end{minipage} % \begin{minipage}[c]{0.5\linewidth} {\small \begin{verbatim} \mess{m}{envleft}{i} \order{i}{j}[1] \nextlevel \mess{k}{j}{envright} \end{verbatim} } \end{minipage} \subsection{Instance regions} \label{regions} A part of the instance axis can be drawn in a different style. Such a part is called an {\em instance region}. The following regions are supported: {\em coregion} (the instance axis is dashed, which means that the order of the attached instances is immaterial), {\em suspension region} (a small rectangle with dashed left and right sides, which denotes that the instance is suspended), {\em activation region} (a small filled rectangle, which denotes that the instance has control). The following commands are used to draw an instance region. \begin{verbatim} \regionstart{type}{instname} \regionend{instname} \end{verbatim} If the \verb+\regionstart+ command is used the instance axis of \verb+instname+ is drawn in the shape determined by \verb+type+, starting from the current level. The type can have values \verb+coregion+, \verb+suspension+, and \verb+activation+. The shape of an instance region can be controlled with the following parameters (see Section~\ref{parameters}): \verb+\regionbarwidth+ (the width of the coregion start and end symbol), \verb+\instwidth+ (the width of the fat instance rectangle), \verb+\regionwidth+ (the width of the activation and suspension rectangle). In the following example, several instance regions are demonstrated. Notice the relative order of \verb|\mess|, \verb|\regionstart|, and \verb|\regionend| commands. Interchanging lines \verb|\regionstart{activation}{i}| and \verb|\mess{q}{j}{i}| makes the arrow head of the~`q' message partly invisible. Also note that the second activation region on~$i$ ends with a method reply (which is produced by the command \cmd{mess*}). \medskip \begin{minipage}[c]{0.4\linewidth} \begin{msc}{regions} \setmscvalues{small} \setlength{\topheaddist}{0.8cm} \declinst{i}{}{i} \declinst{j}{}{j} \declinst{k}{}{k} \regionstart{activation}{i} \nextlevel[3] \regionend{i} \mess{m}{i}{j} \nextlevel \regionstart{coregion}{j} \nextlevel \regionstart{suspension}{k} \mess{p}{j}{k} \nextlevel \regionstart{activation}{i} \mess{q}{j}{i} \nextlevel \regionend{j} \nextlevel[3] \regionend{i} \mess*{r}{i}{j} \nextlevel \mess{s}{j}{k} \regionend{k} \nextlevel \end{msc} \end{minipage} % \begin{minipage}[c]{0.5\linewidth} {\scriptsize \begin{verbatim} \regionstart{activation}{i} \nextlevel[3] \regionend{i} \mess{m}{i}{j} \nextlevel \regionstart{coregion}{j} \nextlevel \regionstart{suspension}{k} \mess{p}{j}{k} \nextlevel \regionstart{activation}{i} \mess{q}{j}{i} \nextlevel \regionend{j} \nextlevel[3] \regionend{i} \mess*{r}{i}{j} \nextlevel \mess{s}{j}{k} \regionend{k} \nextlevel \end{verbatim} } \end{minipage} In some situations, the gray-colored activation regions can hide message-labels. \emph{Level back-up} can help in these situations, see the \emph{Tricks} section in the reference manual~\cite{BM02}. \subsection{Instance creation and instance stop} \label{createstop} The \MSC{} language offers constructs for dynamic instance creation and instance destruction. An instance can dynamically create another instance by issuing a create command. An instance creation is drawn as a dashed message arrow. At the side of the arrow head, the instance head symbol for the created instance is drawn. An instance end symbol does not denote the end of the specified process, but merely the end of its current description. Therefore, a different symbol is needed which denotes that an instance stops before the end of the \MSC{} in which it is contained. The instance stop symbol is a cross. The following commands are used for instance creation and instance stop. \begin{verbatim} \dummyinst{createdinst} \create{name} [labelpos] {creator} [placement] {createdinst} {instancenameabove} {instancenamewithin} \stop{instance} \end{verbatim} In order to reserve space for an instance which will be created dynamically, the command \verb+dummyinst+ must be used. This command is mixed with the declarations of normal instances (see the \verb+declinst+ command, Section~\ref{instances}). The argument \verb+createdinst+ is the nickname of the instance that will be created later. An instance can be created with the \verb+\create+ command. This command results in a dashed horizontal message arrow labeled with \verb+name+. The arrow starts at the current level at the instance with nickname \verb+creator+ and ends at the current level at the instance head of the instance with nickname \verb+createdinst+. This instance must have been declared first with the \verb+dummyinst+ command. The name of the created instance consists of two parts. The part called \verb+instancenameabove+ is placed above the instance head and the \verb+instancenamewithin+ is centered within the instance head. As with normal messages, placement of the message label is controlled by the optional parameters \verb+labelpos+ and \verb+placement+. That is, \verb+labelpos+ denotes the relative position of the message label with respect to the message arrow. Valid values are \verb+t+ (on top) and \verb+b+ (below). The default value is \verb+t+. The optional parameter \verb+placement+ denotes the relative distance of the message label with respect to the beginning of the arrow. Valid values are real numbers in the closed interval $[0,1]$. The default value is~$0.5$. See Figure~\ref{fig:refpoints} (page~\pageref{fig:refpoints}) and its description in Section~\ref{messages} for more information on the placement of message labels. An instance is stopped with the \verb+\stop+ command. The \verb+instance+ is the nickname of the stopped instance. The instance axis is not drawn any further below the level at which the \verb+\stop+ command is issued. Also, the instance foot symbol is not drawn. The size of the stop symbol is determined by the parameter \verb+\stopwidth+ (see Section~\ref{parameters}). The following parameters apply to the instance head symbol: \verb+\instheadheight+ (the height of the instance head symbol), \verb+\instwidth+ (the width of the instance head symbol), and \verb+\labeldist+ (the distance between the instance head symbol and the part of the instance name drawn above the head symbol). Take care not to specify any events on an instance which has not yet been created or which has already been stopped. This may lead to unexpected drawings. However, it is possible to create an instance after it has stopped, as showed in the next example. \medskip \begin{minipage}[c]{0.4\linewidth} \begin{msc}{dynamic instances} \setmscvalues{small} \setlength{\topheaddist}{0.8cm} \declinst{i}{}{i} \dummyinst{j} \declinst{k}{}{k} \mess{p}{i}{k} \nextlevel[3] \create{kick}{k}{j}{}{j} \nextlevel \stop{k} \nextlevel \mess{ok}{j}{i} \nextlevel \stop{j} \nextlevel[2] \create{start}[b]{i}[.75]{k}{}{again} \nextlevel[2] \end{msc} \end{minipage} % \begin{minipage}[c]{0.5\linewidth} {\small \begin{verbatim} \declinst{i}{}{i} \dummyinst{j} \declinst{k}{}{k} \mess{p}{i}{k} \nextlevel[3] \create{kick}{k}{j}{}{j} \nextlevel \stop{k} \nextlevel \mess{ok}{j}{i} \nextlevel \stop{j} \nextlevel[2] \create{start}[b]{i}[.75]{k}{}{again} \nextlevel[2] \end{verbatim} } \end{minipage} \subsection{\MSC{} references} \label{references} Within an \MSC{} a reference to other \MSC{}s can be included. Such a reference is drawn as a rectangle with rounded corners, covering part of the \MSC{}. The following commands are used to draw \MSC{} references. \begin{verbatim} \referencestart[lo][ro]{nickname}{text}{leftinstance}{rightinstance} \referenceend{nickname} \end{verbatim} The reference symbol starts at the level where the \verb+\referencestart+ command is used, and ends at the level where the corresponding \verb+\referenceend+ command occurs. These commands correspond if they have the same \verb+nickname+. The \verb+text+ is placed in the center of the reference symbol. The reference covers all instances from \verb+leftinstance+ to \verb+rightinstance+. The distance between the left (right) edge of the reference symbol and the leftmost (rightmost) covered instance axis is defined by the optional overlap value \verb+lo+. The default value for \verb+lo+ in large/normal/small \MSC{}s is 1.5/1/0.75 (see Section~\ref{parameters} for selecting large, normal or small drawing mode). If the second optional value \verb+ro+ is present too, the optional value \verb+lo+ defines the left overlap and the optional value \verb+ro+ defines the right overlap. The left and right edge of the reference symbol are \verb+nicknameleft+ and \verb+nicknameright+, where \verb+nickname+ is the nickname of the \MSC{} reference as defined in the \verb+\referencestart+ command. These names can be used at every place where the nickname of an instance is required, e.g.\ as the sender or receiver of a message. This is shown in the following example. \medskip \begin{minipage}[c]{0.4\linewidth} \begin{msc}{references} \setmscvalues{small} \setlength{\topheaddist}{0.8cm} \declinst{i}{}{i} \declinst{j}{}{j} \declinst{k}{}{k} \mess{a}{j}{k} \nextlevel \referencestart{r}{a reference}{i}{j} \nextlevel \mess{b}{rright}{k} \nextlevel \referenceend{r} \nextlevel \referencestart{p}{another reference}{i}{k} \nextlevel \mess{c}{envright}{pright} \nextlevel[3] \referenceend{p} \end{msc} \end{minipage} % \begin{minipage}[c]{0.55\linewidth} {\small \begin{verbatim} \mess{a}{j}{k} \nextlevel \referencestart{r}{a reference}{i}{j} \nextlevel \mess{b}{rright}{k} \nextlevel \referenceend{r} \nextlevel \referencestart{p}{another reference}{i}{k} \nextlevel \mess{c}{envright}{pright} \nextlevel[3] \referenceend{p} \end{verbatim} } \end{minipage} \subsection{Inline expressions} \label{inlines} An inline expression is a part of an \MSC{} on which an operation is defined. A rectangle surrounds the part of the \MSC{} containing the operands. The operands are separated by horizontal dashed lines. The operator is placed in the upper left corner of the inline expression symbol. The following commands are used to draw inline expressions. \begin{verbatim} \inlinestart[lo][ro]{nickname}{operator}{leftinstance}{rightinstance} \inlineseparator{nickname} \inlineend(*){nickname} \end{verbatim} The inline expression starts at the level where the \verb+\inlinestart+ command occurs. The inline expression spans over the instances from \verb+leftinstance+ to \verb+rightinstance+. The \verb+operand+ is placed in the upper left corner of the rectangle. At every level where a corresponding \verb+\inlineseparator+ command occurs, a dashed line is drawn. The inline expression ends at the level where the \verb+\inlineend+ command occurs. The \verb+nickname+ is used to match corresponding commands. The command \verb+\inlineend*+ does the same as the command \verb+\inlineend+, except that the bottom line of the rectangle is dashed. This is used to indicate that the operand is optional. The left and right edge of the inline expression symbol are named \verb+nicknameleft+ and \verb+nicknameright+, where \verb+nickname+ is the nickname of the inline expression as defined in the \verb+\inlinestart+ command. These names can be used at every place where the nickname of an instance is required, e.g.\ as the sender or receiver of a message. The distance between the left (right) edge of the inline expression symbol and the leftmost (rightmost) included instance axis is defined by the optional overlap value \verb+lo+. The default value for large/normal/small \MSC{}s is 1.5/1/0.75 (see Section~\ref{parameters} for selecting large, normal or small drawing mode). If the second optional value \verb+ro+ is present too, the optional value \verb+lo+ defines the left overlap and the optional value \verb+ro+ defines the right overlap. These options make it possible to easily draw nested inline expressions as in the following example. \medskip \begin{minipage}[c]{0.4\linewidth} \begin{msc}{inline expressions} \setmscvalues{small} \setlength{\topheaddist}{0.8cm} \declinst{i}{}{i} \declinst{j}{}{j} \declinst{k}{}{k} \inlinestart{exp1}{par}{i}{k} \nextlevel \mess{a}{k}{j} \nextlevel \inlinestart[0.6cm]{exp2}{alt}{i}{j} \nextlevel[2] \mess{b}{j}{i} \nextlevel \inlineseparator{exp2} \nextlevel \mess{c}{j}{i} \nextlevel \inlineend{exp2} \nextlevel \inlineseparator{exp1} \nextlevel \mess{d}{j}{k} \nextlevel \inlineend{exp1} \nextlevel \inlinestart{exp3}{opt}{i}{j} \nextlevel \mess{e}{envright}{exp3right} \mess{e}{exp3right}{j} \nextlevel \mess{f}{j}{i} \nextlevel \inlineend*{exp3} \end{msc} \end{minipage} % \begin{minipage}[c]{0.5\linewidth} {\scriptsize \begin{verbatim} \inlinestart{exp1}{par}{i}{k} \nextlevel \mess{a}{k}{j} \nextlevel \inlinestart[0.6cm]{exp2}{alt}{i}{j} \nextlevel[2] \mess{b}{j}{i} \nextlevel \inlineseparator{exp2} \nextlevel \mess{c}{j}{i} \nextlevel \inlineend{exp2} \nextlevel \inlineseparator{exp1} \nextlevel \mess{d}{j}{k} \nextlevel \inlineend{exp1} \nextlevel \inlinestart{exp3}{opt}{i}{j} \nextlevel \mess{e}{envright}{exp3right} \mess{e}{exp3right}{j} \nextlevel \mess{f}{j}{i} \nextlevel \inlineend*{exp3} \end{verbatim} } \end{minipage} \subsection{Gates} \label{gates} A gate determines a connection point for messages. The following command can be used to draw gates. \begin{verbatim} \gate(*)[hpos][vpos]{gatename}{instname} \end{verbatim} The unstarred version produces a normal (invisible) gate. The starred version produces a visible gate (a small dot). The gate is drawn at the current level at the instance \verb+instname+ (which can also be the left and right edge of e.g.\ an \MSC{} reference). The \verb+gatename+ is attached to the gate. The positioning of the \verb+gatename+ relative to the gate is determined by the values of \verb+hpos+ (horizontal position) and \verb+vpos+ (vertical position). Possible values for \verb+hpos+ are \verb+l+ (left, default) and \verb+right+ (right). Possible values for \verb+vpos+ are \verb+t+ (top, default), \verb+c+ (center), and \verb+b+ (bottom). There are several parameters to control the size and shape of the gate symbol (see Section~\ref{parameters}). These are \verb+\gatesymbolradius+ (sets the radius of the gate symbol), \verb+\labeldist+ (the vertical distance between the gate name and the gate). The next example shows a number of gates. \medskip \begin{minipage}[c]{0.4\linewidth} \begin{msc}{gates} \setmscvalues{small} \declinst{i}{}{i} \declinst{j}{}{j} \declinst{k}{}{k} \referencestart{r}{ref}{i}{j} \nextlevel \gate{$g$}{rright} \mess{b}{rright}{envright} \gate[r][c]{$h$}{envright} \nextlevel \nextlevel \mess{c}{rright}{k} \gate*[l][b]{$h'$}{rright} \nextlevel[2] \referenceend{r} \end{msc} \end{minipage} % \begin{minipage}[c]{0.5\linewidth} {\footnotesize \begin{verbatim} \declinst{i}{}{i} \declinst{j}{}{j} \declinst{k}{}{k} \referencestart{r}{ref}{i}{j} \nextlevel \gate{$g$}{rright} \mess{b}{rright}{envright} \gate[r][c]{$h$}{envright} \nextlevel \nextlevel \mess{c}{rright}{k} \gate*[l][b]{$h'$}{rright} \nextlevel[2] \referenceend{r} \end{verbatim} } \end{minipage} \subsection{High-level \MSC{}s} \label{hmsc} A High-level \MSC{} (\HMSC{}) is a drawing which defines the relation between a number of \MSC{}s. It is composed of a start symbol (an upside down triangle), a number of end symbols (represented by triangles), a number of \MSC{} references (these are rectangles with rounded corners), a number of conditions (hexagons) and possibly several connection points (circles). These symbols are connected by arrows. The following commands can be used to draw \HMSC{}s. \begin{verbatim} \begin{hmsc}[headerpos]{hmscname}(llx,lly)(urx,ury) \end{hmsc} \hmscstartsymbol{nickname}(x,y) \hmscendsymbol{nickname}(x,y) \hmscreference{nickname}{text}(x,y) \hmsccondition{nickname}{text}(x,y) \hmscconnection{nickname}(x,y) \arrow{from-nickname}[coord-list]{to-nickname} \end{verbatim} In order to draw \HMSC{}s, a new environment is defined, which is called \verb+hmsc+. The command to begin this environment has several arguments. The argument \verb+headerpos+ is optional. It controls positioning of the header of the \HMSC{}. This argument can have values \verb+l+ (for a left aligned header), \verb+c+ (for a centered header) and \verb+r+ (for a right aligned header). The header of an \HMSC{} is formed from the keyword \verb+msc+, followed by the \verb+hmscname+. The size of the \HMSC{} frame is determined by the coordinates of the lower-left corner, \verb+(llx,lly)+, and the coordinates of the upper-right corner, \verb+(urx,ury)+. The \HMSC{} grid is not drawn, but used to control the positioning of the \HMSC{} symbols (\verb+startsymbol+, \verb+endsymbol+, \verb+reference+, \verb+condition+, and \verb+connection+). The center of each symbol is drawn on the grid point with coordinates \verb+{x,y}+. Each symbol also has a \verb+nickname+ for later reference. \HMSC{} symbols can be connected by means of the \verb+arrow+ command. This draws an arrow from the symbol with nickname \verb+from-nickname+ to the symbol with nickname \verb+to-nickname+. The optional argument \verb+coord-list+ can be used if the line connecting the source and the destination should not be straight. The \verb+coord-list+ has the following syntax: \verb+(x1,y1)(x2,y2)...(xk,yk)+. This means that the connecting line goes through the points with coordinates (x1,y1), (x2,y2), \ldots, (xk,yk). Arrows always leave the start symbol at the bottom. They enter the end symbol at the top. Arrows start and end either at the middle of the top or at the middle of the bottom of a reference and condition symbol. The incoming (outgoing) direction of the arrow determines whether it will start (end) at the top or at the bottom. There are several parameters to control the size and shape of the symbols (see Section~\ref{parameters}). These are \verb+\hmscconditionheight+ (the height of the condition symbol), \verb+\hmscconditionwidth+ (the width of the condition symbol, excluding the left and right angular parts), \verb+\hmscreferenceheight+ (the height of the reference symbol), \verb+\hmscreferencewidth+ (the width of the reference symbol), \verb+\messarrowscale{size}+ (a command to set the size of the arrow head of a connection line); \verb+setconnectiontype(type)+ (set the shape of the polyline connection the symbols; \verb+type+ can be \verb+straight+, \verb+rounded+, and \verb+curved+), \verb+\startsymbolwidth+ (the width of the start and end symbol), \verb+\topnamedist+ (sets the distance between the top of the \HMSC{} frame and the \HMSC{} header). An example of an \HMSC{} is in the following diagram. Notice that the width and height of reference symbols are changed locally (i.e., between \verb+{+ and \verb+}+ braces) just before the big reference~\verb+b+ is defined. \medskip \noindent \begin{minipage}[c]{0.375\linewidth} \begin{hmsc}{High level}(-3,0)(3,12) \hmscstartsymbol{s}(0,10) \hmscreference{a}{A}(0,9) \hmscconnection{c}(0,7.5) { \setlength{\hmscreferencewidth}{2cm} \setlength{\hmscreferenceheight}{3\baselineskip} \hmscreference{b}{\parbox{1.9cm} {\centering this is a big hmsc reference} }(0,6) } \hmsccondition{t}{Again}(1,4.25) \hmsccondition{ok}{Ok}(0,3.5) \hmsccondition{q}{\textit{Break}}(-2,3.5) \hmscendsymbol{e1}(-2,2) \hmscreference{do}{Do it!}(0,2) \hmscendsymbol{e2}(0,1) \arrow{s}{a} \arrow{a}{c} \arrow{c}{b} \arrow{c}[(-2,7.5)]{q} \arrow{b}{q} \arrow{q}{e1} \arrow{b}{ok} \arrow{ok}{do} \arrow{do}{e2} \arrow{b}{t} \arrow{t}[(1,3.5)(2.5,3.5)(2.5,7.5)]{c} \end{hmsc} \end{minipage}\hfill \begin{minipage}[c]{0.6\linewidth} {\footnotesize \begin{verbatim} \begin{hmsc}{High level}(-3,0)(3,12) \hmscstartsymbol{s}(0,10) \hmscreference{a}{A}(0,9) \hmscconnection{c}(0,7.5) {\setlength{\hmscreferencewidth}{2cm} \setlength{\hmscreferenceheight} {3\baselineskip} \hmscreference{b}{\parbox{1.9cm} {\centering this is a big hmsc reference} }(0,6)} \hmsccondition{t}{Again}(1,4.5) \hmsccondition{ok}{Ok}(0,3.5) \hmsccondition{q}{\textit{Break}}(-2,3.5) \hmscendsymbol{e1}(-2,2) \hmscreference{do}{Do it!}(0,2) \hmscendsymbol{e2}(0,1) \arrow{s}{a} \arrow{a}{c} \arrow{c}{b} \arrow{c}[(-2,7.5)]{q} \arrow{b}{q} \arrow{q}{e1} \arrow{b}{ok} \arrow{ok}{do} \arrow{do}{e2} \arrow{b}{t} \arrow{t}[(1,3.5)(2.5,3.5)(2.5,7.5)]{c} \end{hmsc} \end{verbatim} } \end{minipage} \subsection{\MSC{} documents} \label{mscdoc} An \MSCdoc{} is a drawing which contains various declarations of objects used in the \MSC{} description. For drawing \MSCdoc{}s he following commands are provided. \begin{verbatim} \begin{mscdoc}[headerpos]{mscdocname}{text}(llx,lly)(urx,ury) \end{mscdoc} \reference{text}(x,y) \separator{y} \end{verbatim} As for \MSC{} and \HMSC{}, a new environment is defined, which is named \verb+mscdoc+. The command to begin an \MSCdoc{} has several arguments. The argument \verb+headerpos+ is optional. It controls positioning of the header of the \MSCdoc{}. This argument can have values \verb+l+ (for a left aligned header), \verb+c+ (for a centered header) and \verb+r+ (for a right aligned header). The header of an \MSCdoc{} is formed from the keyword \verb+mscdocument+, followed by the \verb+mscdocname+. The \verb+text+ is placed left-aligned below the \MSCdoc{} header. The size of the \MSCdoc{} frame is determined by coordinates of the lower-left corner, \verb+(llx,lly)+, and the coordinates of the upper-right corner, \verb+(urx,ury)+. The \MSCdoc{} grid is not drawn, but used to control the positioning of the \MSC{} references. The center of such a reference is drawn on the grid point with coordinates \verb+{x,y}+. The \verb+separator+ command draws a dashed horizontal line. The \MSC{} references above the separator are the exported, while the ones below the separator are local. There are several parameters to control the size and shape of the symbols (see Section~\ref{parameters}). \verb+\mscdocreferenceheight+ (the height of the reference symbol), \verb+\mscdocreferencewidth+ (the width of the reference symbol), \verb+\topnamedist+ (sets the distance between the top of the \MSCdoc{} frame and the \MSCdoc{} header). An example of an \MSCdoc{} is in the following diagram. Notice that the size of references in an \MSCdoc{} had to be changed for the last reference. \medskip \begin{minipage}{0.4\linewidth} \begin{mscdoc}{My declarations}% (0,0)(6,8) \reference{a}(1,6) \reference{b}(3,6) \reference{c}(1,4) \reference{d}(3,4) \separator{3} \setlength{\mscdocreferencewidth}{4.5\mscunit} \setlength{\mscdocreferenceheight}{2\baselineskip} \reference{% \parbox{4\mscunit}% {\raggedright This is a two-line reference}} (3,1.5) \end{mscdoc} \end{minipage} % \begin{minipage}{0.5\linewidth} {\small \begin{verbatim} \begin{mscdoc}{My declarations}% (0,0)(6,8) \reference{a}(1,6) \reference{b}(3,6) \reference{c}(1,4) \reference{d}(3,4) \separator{3} \setlength{\mscdocreferencewidth} {4.5\mscunit} \setlength{\mscdocreferenceheight} {2\baselineskip} \reference{% \parbox{4\mscunit}% {\raggedright This is a two-line reference}} (3,1.5) \end{mscdoc} \end{verbatim} } \end{minipage} \section{Style parameters} \label{parameters} By means of a collection of parameters, the graphical appearance of an \MSC{} can be fine tuned to the user's taste. The general parameters are displayed in Figure~\ref{parametersfig} on page~\pageref{parametersfig}. %======================== \begin{figure}[htb] \vspace{2ex} %Needed to get enough white space before the top label of %the figure. \newcommand{\printlength}[1]{\mbox{\footnotesize\ttfamily \char`\\#1}} \begin{center} \setmscvalues{normal} \begin{msc}{Lengths} \psset{linewidth=.4pt,dotsep=1pt} \newlength{\lta} \newlength{\ltb} % \topnamedist \psline[linestyle=dotted](1.5cm,-\topnamedist)(2.5cm,-\topnamedist) \psline[arrowscale=1.3]{->}(2.5cm,.2cm)(2.5cm,0cm) \setlength{\lta}{\topnamedist+.2cm} \psline[arrowscale=1.3]{->}(2.5cm,-\lta)(2.5cm,-\topnamedist) \rput[tl](2.5cm,.4cm){\printlength{topnamedist}} % \leftnamedist \setlength{\lta}{\leftnamedist+10pt} \setlength{\ltb}{\topnamedist} \psline[linestyle=dotted,arrowscale=1.0]{->}(-10pt,-\ltb)(0,-\ltb) \psline[linestyle=dotted,arrowscale=1.0]{->}(\lta,-\ltb)(\leftnamedist,-\ltb) \psline[linestyle=dotted](\leftnamedist,10pt)(\leftnamedist,-\baselineskip) \rput[br](-10pt,-\ltb){\printlength{leftnamedist}} % \topheaddist \setlength{\lta}{\envinstdist+\instdist-.5\instwidth} \psline[arrowscale=1.3,linestyle=dotted]{<->}(\lta,0cm)(\lta,-\topheaddist) \rput[l](\lta,-.5\topheaddist){ \printlength{topheaddist}} % \bottomfootdist \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\lastlevelheight+\instfootheight+\levelheight*12} \setlength{\lta}{\envinstdist+2\instdist-.5\instwidth} \rput[tl](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(0,-\bottomfootdist)} \setlength{\ltb}{\ltb+.5\bottomfootdist} \rput[l](\lta,-\ltb){\printlength{bottomfootdist}} % \instheadheight \setlength{\lta}{\envinstdist+2\instdist+.5\instwidth+.2cm} \setlength{\ltb}{\topheaddist} \rput[t](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(0,-\instheadheight)} \setlength{\ltb}{\ltb+.5\instheadheight} \rput[l](\lta,-\ltb){\printlength{instheadheight}} % \firstlevelheight \setlength{\lta}{\envinstdist+\instdist+.2cm} \setlength{\ltb}{\topheaddist+\instheadheight} \rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,-\firstlevelheight)} \setlength{\ltb}{\ltb+.5\firstlevelheight} \rput[l](\lta,-\ltb){\printlength{firstlevelheight}} % \levelheight \setlength{\lta}{\envinstdist+\instdist+.2cm} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight} \rput[t](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(0,-\levelheight)} \setlength{\ltb}{\ltb+.5\levelheight} \rput[l](\lta,-\ltb){\printlength{levelheight}} % \actionheight \setlength{\lta}{\envinstdist+2\instdist+0.5\actionwidth+.2cm} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*7} \rput[t](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(0,-\actionheight)} \setlength{\ltb}{\ltb+.7\actionheight} \rput[bl](\lta,-\ltb){\printlength{actionheight}} % \actionwidth \setlength{\lta}{\envinstdist+2\instdist-0.5\actionwidth} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*7-.2cm} \rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\actionwidth,0)} \setlength{\lta}{\lta+.5\actionwidth} \setlength{\ltb}{\ltb-.1cm} \rput[bl](\lta,-\ltb){\rule{0pt}{2ex}\printlength{actionwidth}} % \conditionheight \setlength{\lta}{\envinstdist+2\instdist+\conditionoverlap+0.8\conditionheight} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*10} \rput[t](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(0,-\conditionheight)} \setlength{\ltb}{\ltb+.7\conditionheight} \rput[bl](\lta,-\ltb){\printlength{conditionheight}} % \inlineoverlap \setlength{\lta}{\envinstdist} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*5-.2cm} \rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\inlineoverlap,0)} %\setlength{\lta}{\lta+\inlineoverlap} \setlength{\ltb}{\ltb-.1cm} \rput[bl](\lta,-\ltb){\rule{0pt}{2ex}\printlength{inlineoverlap}} % \referenceoverlap \setlength{\lta}{\envinstdist} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*7-.2cm} \rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\referenceoverlap,0)} %\setlength{\lta}{\lta+\referenceoverlap} \setlength{\ltb}{\ltb-.1cm} \rput[bl](\lta,-\ltb){\rule{0pt}{2ex}\printlength{referenceoverlap}} % \conditionoverlap \setlength{\lta}{\envinstdist+2\instdist} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*10-.2cm} \rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\conditionoverlap,0)} %\setlength{\lta}{\lta+\conditionoverlap} \setlength{\ltb}{\ltb-.1cm} \rput[bl](\lta,-\ltb){\rule{0pt}{2ex}\printlength{conditionoverlap}} % \lastlevelheight \setlength{\lta}{\envinstdist+2\instdist+.2cm} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*12} \rput[t](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(0,-\lastlevelheight)} %\setlength{\ltb}{\ltb+.5\lastlevelheight} \rput[bl](\lta,-\ltb){\printlength{lastlevelheight}} % \instfootheight \setlength{\lta}{\envinstdist+2\instdist+.5\instwidth+.1cm} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*12+\lastlevelheight} \rput[t](\lta,-\ltb){\psline[arrowscale=1.3]{->}(0,.3cm)(0,0)} \setlength{\ltb}{\ltb+\instfootheight} \rput[t](\lta,-\ltb){\psline[arrowscale=1.3]{->}(0,-.3cm)(0,0)} \rput[tl](\lta,-\ltb){ \printlength{instfootheight}} % \selfmesswidth \setlength{\lta}{\envinstdist-\selfmesswidth} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*2-.2cm} \rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\selfmesswidth,0)} %\setlength{\lta}{\lta+\selfmesswidth} \rput[r](\lta,-\ltb){\printlength{selfmesswidth}} % \regionbarwidth \setlength{\lta}{\envinstdist+2\instdist-.5\regionbarwidth} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*2-.2cm} \rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\regionbarwidth,0)} \setlength{\lta}{\lta+\regionbarwidth} \rput[l](\lta,-\ltb){\printlength{regionbarwidth}} % \instwidth \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\lastlevelheight+\instfootheight+\levelheight*12+.2cm} \setlength{\lta}{\envinstdist-0.5\instwidth} \rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\instwidth,0)} \rput[tl](\lta,-\ltb){\rule{0pt}{2ex}\printlength{instwidth}} % \instdist \setlength{\lta}{\envinstdist} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+2.5\levelheight} \rput[l](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\instdist,0)} \setlength{\lta}{\lta+.5\instdist} \setlength{\ltb}{\ltb-.1cm} \rput[b](\lta,-\ltb){\printlength{instdist}} % \envinstwidth \setlength{\lta}{0cm} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+.5\levelheight} \rput[l](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\envinstdist,0)} \rput[tl](\lta,-\ltb){ \printlength{envinstdist}} % \labeldist \setlength{\lta}{\envinstdist-.5\instwidth} \setlength{\ltb}{\topheaddist-\labeldist} \rput[l](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted](-.2cm,0)(.5cm,0)} \rput[b](\lta,-\ltb){\psline[arrowscale=1.3]{->}(-.1cm,.3cm)(-.1cm,0)} \setlength{\ltb}{\topheaddist} \rput[l](\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted](-.2cm,0)(.5cm,0)} \rput[b](\lta,-\ltb){\psline[arrowscale=1.3]{->}(-.1cm,-.3cm)(-.1cm,0)} \rput[tr](\lta,-\ltb){\printlength{labeldist} } % \timerwidth \setlength{\lta}{\envinstdist-\selfmesswidth-0.5\timerwidth} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*4+.4cm} \rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\timerwidth,0)} %\setlength{\lta}{\lta+\selfmesswidth} \rput[r](\lta,-\ltb){\printlength{timerwidth}} % \stopwidth \setlength{\lta}{\envinstdist+\instdist-0.5\stopwidth} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*4+0.5\stopwidth+.1cm} \rput(\lta,-\ltb){\psline[arrowscale=1.3,linestyle=dotted]{<->}(0,0)(\stopwidth,0)} \setlength{\lta}{\lta+\stopwidth} \rput[l](\lta,-\ltb){\printlength{stopwidth}} % \lostsymbolradius \setlength{\lta}{\envinstdist+2\instdist+\selfmesswidth+2\lostsymbolradius+0.1cm} \setlength{\ltb}{\topheaddist+\instheadheight+\firstlevelheight+\levelheight*4} \rput[t](\lta,-\ltb){\psline[arrowscale=1.3]{->}(0,.3cm)(0,0)} \setlength{\ltb}{\ltb+\lostsymbolradius} \rput[t](\lta,-\ltb){\psline[arrowscale=1.3]{->}(0,-.3cm)(0,0)} \rput[tl](\lta,-\ltb){ \printlength{lostsymbolradius}} \psset{linewidth=.8pt,dotsep=3pt} \declinst{m1}{aname}{iname} \declinst{st}{}{} \declinst{m2}{}{} \mess{msg1}{m1}{st} \nextlevel \mess{msg2}{m1}{st} \nextlevel \mess{self}{m1}{m1} \coregionstart{m2} \nextlevel \coregionend{m2} \nextlevel \lost[r]{x}{}{m2} \stop{st} \settimer{T}{m1} \nextlevel \inlinestart{alt}{alt}{m1}{m1} \nextlevel[2] \inlineend{alt} \action{a}{m2} \nextlevel \referencestart{ref}{reference}{m1}{m1} \nextlevel \referenceend{ref} \nextlevel \condition{cond1}{m1,m2} \nextlevel \nextlevel \mess{msg3}{m2}{m1} \end{msc} \end{center} \caption{User controllable parameters} \label{parametersfig} \end{figure} The value of a parameter can be changed using standard \LaTeX\ commands, e.g. \begin{verbatim} \setlength{\levelheight}{1cm} \end{verbatim} The following list describes all parameters. The default values for drawing \MSC{}s at large, normal and small size are included. See the command \verb+\setmscvalues{size}+ below for restoring the parameters to their original values. %======================== \begin{defs} \item[\cmd{actionheight}] Height of action symbols.\\ (\lnsvalue{0.75}{0.6}{0.5} cm.) \item[\cmd{actionwidth}] Width of action symbol.\\ (\lnsvalue{1.25}{1.25}{1.2} cm.) \item[\cmd{bottomfootdist}] Distance between bottom of foot symbol and frame.\\ (\lnsvalue{1.0}{0.7}{0.5} cm.) \item[\cmd{commentdist}] Distance between a comment and its instance.\\ (\lnsvalue{0.5}{0.5}{0.5} cm.) \item[\cmd{conditionheight}] Height of condition symbols.\\ (\lnsvalue{0.75}{0.6}{0.5} cm.) \item[\cmd{conditionoverlap}] Overlap of condition symbol.\\ (\lnsvalue{0.6}{0.5}{0.4} cm.) \item[\cmd{envinstdist}] Distance between environments and nearest instance line.\\ (\lnsvalue{2.5}{2.0}{1.2} cm.) \item[\cmd{firstlevelheight}] Height of level just below head symbols. Should not be changed inside the \MSC{} environment.\\ (\lnsvalue{0.75}{0.6}{0.4} cm.) \item[\cmd{hmscconditionheight}] Height of \HMSC{} condition symbol.\\ (\lnsvalue{0.375}{0.3}{0.25} cm.) \item[\cmd{hmscconditionwidth}] Width of \HMSC{} condition symbol.\\ (\lnsvalue{1.0}{0.8}{0.7} cm.) \item[\cmd{hmscconnectionradius}] Radius of \HMSC{} connection symbol.\\ (\lnsvalue{0.06}{0.05}{0.04} cm.) \item[\cmd{hmscreferenceheight}] Height of \HMSC{} reference symbol.\\ (\lnsvalue{0.375}{0.3}{0.25} cm.) \item[\cmd{hmscreferencewidth}] Width of \HMSC{} reference symbol.\\ (\lnsvalue{1.0}{0.8}{0.7} cm.) \item[\cmd{hmscstartsymbolwidth}] Width of \HMSC{} start symbol.\\ (\lnsvalue{0.75}{0.6}{0.3} cm.) \item[\cmd{inlineoverlap}] Overlap of inline symbol.\\ (\lnsvalue{1.5}{1.0}{0.75} cm.) \item[\cmd{instbarwidth}] Default width of vertical instance bars (applies to fat instances only).\\ (\lnsvalue{0.0}{0.0}{0.0} cm.) \item[\cmd{instdist}] Distance between instance axes.\\ (\lnsvalue{3.0}{2.2}{1.5} cm.) \item[\cmd{instfootheight}] Height of foot symbols. Should not be changed inside the \MSC{} environment.\\ (\lnsvalue{0.25}{0.2}{0.15} cm.) \item[\cmd{instheadheight}] Height of head symbols. Should not be changed inside the \MSC{} environment.\\ (\lnsvalue{0.6}{0.55}{0.5} cm.) \item[\cmd{instwidth}] Width of header and foot symbols.\\ (\lnsvalue{1.75}{1.6}{1.2} cm.) \item[\cmd{labeldist}] Distance between labels and the symbols to which they belong (for instance, message labels and arrows).\\ (\lnsvalue{1.0}{1.0}{1.0} ex.) \item[\cmd{lastlevelheight}] Height of level just above foot symbols. Should not be changed inside the \MSC{} environment.\\ (\lnsvalue{0.5}{0.4}{0.3} cm.) \item[\cmd{leftnamedist}] Distance between left of the frame and (left of) \MSC, \HMSC, or \MSCdoc{} title.\\ (\lnsvalue{0.3}{0.2}{0.1} cm.) \item[\cmd{levelheight}] Height of a level.\\ (\lnsvalue{0.75}{0.5}{0.4} cm.) \item[\cmd{lostsymbolradius}] Radius of the lost and found symbols.\\ (\lnsvalue{0.15}{0.12}{0.08} cm.) \item[\cmd{markdist}] Horizontal distance from a mark to its instance.\\ (\lnsvalue{1.0}{1.0}{1.0} cm.) \item[\cmd{measuredist}] Horizontal distance from a measure to its (closest) instance.\\ (\lnsvalue{1.0}{1.0}{1.0} cm.) \item[\cmd{measuresymbolwidth}] Width of a measure symbol.\\ (\lnsvalue{0.75}{0.6}{0.4} cm.) \item[\cmd{mscdocreferenceheight}] Height of reference symbol in an \MSCdoc.\\ (\lnsvalue{0.375}{0.3}{0.25} cm.) \item[\cmd{mscdocreferencewidth}] Width of reference symbol in an \MSCdoc.\\ (\lnsvalue{1.0}{0.8}{0.7} cm.) \item[\cmd{referenceoverlap}] Overlap of reference symbol.\\ (\lnsvalue{1.5}{1.0}{0.75} cm.) \item[\cmd{regionbarwidth}] Width of region bars.\\ (\lnsvalue{0.5}{0.4}{0.2} cm.) \item[\cmd{selfmesswidth}] Length of horizontal arms of self messages.\\ (\lnsvalue{0.75}{0.6}{0.4} cm.) \item[\cmd{stopwidth}] Width of the stop symbol.\\ (\lnsvalue{0.6}{0.5}{0.3} cm.) \item[\cmd{timerwidth}] Width of the \emph{timer} symbols.\\ (\lnsvalue{0.4}{0.3}{0.2} cm.) \item[\cmd{topheaddist}] Distance between top of head symbols and frame.\\ (\lnsvalue{1.5}{1.3}{1.2} cm.) \item[\cmd{topnamedist}] Distance between top of the frame and (top of) \MSC, \HMSC, or \MSCdoc{} title.\\ (\lnsvalue{0.3}{0.2}{0.2} cm.) \end{defs} In addition there are several commands which allow the user to adjust the \MSC{} drawing to his own taste. \begin{defs} \item[\cmd{messarrowscale}\{\emph{scalefactor}\}] Sets the scale factor (a positive real number) of message arrow heads. (\lnsvalue{2}{1.5}{1.2}) \item[\cmd{setmscscale}\{\emph{scalefactor}\}] Sets the scale factor of the \MSC{} environment to \emph{scalefactor}. the scale factor is supposed to be a real number. Scaling is done when the \MSC{} environment ends (\verb|\end{msc}|). The default of \emph{scalefactor} is~1. A more consistent way for varying the size of the \MSC{} can be obtained by using the \verb+\setmesvalues+ command as described below. (default value 1.) \item[\cmd{psset}\{\texttt{linewidth=D}\}] This command sets the width of all lines in \MSC{}s, \HMSC{}s, and \MSCdoc{}s to length \verb+D+. If this command is issued outside the msc environment, then the value is set for the complete document. If it is used directly after the start of the msc environment it only holds for this \MSC{}.\\ (large/normal/small value 0.8/0.7/0.6 pt.) \item[\cmd{setfootcolor}\{\emph{color}\}] Sets the color of the foot symbols of \MSC{} instances. Possible values are \emph{black}, \emph{white}, \emph{gray}, or \emph{lightgray}. For more color values, see the documentation of the \LaTeXe{} \textsf{color} package. \end{defs} The following command can be used to set the above mentioned style parameters to suitable values. \begin{defs} \item[\cmd{setmscvalues}\{\emph{size}\}] Sets all parameters of the \mscpack{} to predefined values. Valid values for \emph{size} are: \verb|small|, \verb|normal|, and \verb|large|. (The default value of \verb+size+ is \verb+normal+. This can be used for drawings with at maximum six instances on a sheet of A4 paper. For sizes \verb+large+ and \verb+small+, a maximum of four and nine instances respectively fit on a sheet of A4 paper.) \end{defs} Caution has to be taken when changing the value of a parameter within the \MSC{} definition. The following parameters can be changed within an \MSC{} definition without unexpected side effects: \begin{flushleft} \verb+\actionheight+, \verb+\actionwidth+, \verb+\bottomfootdist+, \verb+\conditionheight+, \verb+\conditionoverlap+, \verb+\inlineoverlap+, \verb+\instfootheight+, \verb+\instwidth+ (however, this may cause different sizes of corresponding instance header and footer symbols), \verb+\labeldist+, \verb+\lastlevelheight+, \verb+\levelheight+, \verb+\lostsymbolradius+, \verb+\referenceoverlap+, \verb+\regionbarwidth+, \verb+\selfmesswidth+, \verb+\stopwidth+, \verb+\timerwidth+, and \verb+\topnamedist+. \end{flushleft} In addition to the parameters specific to the \mscpack, standard \LaTeX\ commands can be used to change the type style and other details. For example, if the command \verb+\sffamily+ is included directly after the start of the msc environment, the text in the \MSC{} is drawn using a {\sf sans serif} font. Likewise, the text size can be changed by inserting, e.g., the command \verb+\small+. The \verb+\raisebox+ and \verb+\parbox+ commands can also be used to position and format names. \section{Example} \label{example} Figure~\ref{ex} on page~\pageref{ex} shows the \MSC{} defined in the following \LaTeX\ fragment. {\small \begin{verbatim} \begin{msc}{Example} \declinst{usr}{The user}{User} \declinst{m1}{Control}{M1} \dummyinst{m2} \declinst{m3}{Another Machine}{M3} \create{start}{m1}{m2}{Processing}{M2} \mess{msg 0}{envleft}{usr} \mess{msg 1}{envright}{m2}[1] \nextlevel \mess{msg 2}{usr}{m1} \order{m1}{m2}[4] \action{a}{m3} \nextlevel \found{msg x}{}{usr} \nextlevel \mess{msg 3}{usr}{m2}[-1] \coregionstart{m1} \settimeout{S}{m3}[2] \nextlevel \mess{msg 4}{m1}{usr} \coregionstart{m2} \settimer[r]{T}{m3} \nextlevel \mess[r]{msg 5}{m2}{m2}[3] \mess{msg 6}{usr}{usr}[2] \nextlevel \mess{msg 7}{m2}{usr} \timeout[r]{T}{m3} \nextlevel \coregionend{m2} \nextlevel \coregionend{m1} \stoptimer[r]{T'}{m3} \nextlevel \lost[r]{msg y}{Mach 1}{usr} \mess{msg 8}{m1}{envright} \nextlevel \condition{condition 1}{usr,m2} \setstoptimer[r]{U}{m3} \nextlevel[2] \stop{usr} \end{msc} \end{verbatim} } \begin{figure}[htb] \begin{center} \begin{msc}{Example} \declinst{usr}{The user}{User} \declinst{m1}{Control}{M1} \dummyinst{m2} \declinst{m3}{Another Machine}{M3} \create{start}{m1}{m2}{Processing}{M2} \mess{msg 0}{envleft}{usr} \mess{msg 1}{envright}{m2}[1] \nextlevel \mess{msg 2}{usr}{m1} \order{m1}{m2}[4] \action{a}{m3} \nextlevel \found{msg x}{}{usr} \nextlevel \mess{msg 3}{usr}{m2}[-1] \coregionstart{m1} \settimeout{S}{m3}[2] \nextlevel \mess{msg 4}{m1}{usr} \coregionstart{m2} \settimer[r]{T}{m3} \nextlevel \mess[r]{msg 5}{m2}{m2}[3] \mess{msg 6}{usr}{usr}[2] \nextlevel \mess{msg 7}{m2}{usr} \timeout[r]{T}{m3} \nextlevel \coregionend{m2} \nextlevel \coregionend{m1} \stoptimer[r]{T'}{m3} \nextlevel \lost[r]{msg y}{Mach 1}{usr} \mess{msg 8}{m1}{envright} \nextlevel \condition{condition 1}{usr,m2} \setstoptimer[r]{U}{m3} \nextlevel[2] \stop{usr} \end{msc} \caption{A menagerie of \MSC{} symbols} \label{ex} \end{center} \end{figure} \section{Acknowledgments} Thanks are due to the following people for providing us with useful input: Peter Peters, Michel Reniers. \bibliographystyle{plain} \bibliography{biblio} \end{document}