%% talkdoc -- (talkdoc.tex) documentation
%% The documentation for the talk class
%% Author: Martin Wiebusch
%%
%% This file may be distributed and/or modified under the
%% conditions of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%% The latest version of this license is in
%%    http://www.latex-project.org/lppl.txt
%% and version 1.3 or later is part of all distributions of LaTeX
%% version 2003/12/01 or later.

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\title{The \pkg{talk} Document Class\thanks{This file has version number 1.0,
    last revised 2005/08/09}}
\author{Martin Wiebusch}

\sloppy

\begin{document}
\maketitle
\begin{abstract}
  The \pkg{talk} document class allows you to create slides for screen
  presentations or printing on transparencies. It also allows you to print
  personal notes for your talk. You can create overlays and display structure
  information (current section / subsection, table of contents) on your slides.
  The main feature that distinguishes \pkg{talk} from other presentation classes
  like \pkg{beamer} or \pkg{prosper} is that it allows the user to define an
  arbitrary number of \emph{slide styles} and switch between these styles from
  slide to slide. This way the slide layout can be adapted to the slide
  content. For example, the title or contents page of a talk can be given a
  slightly different layout than the other slides.

  The \pkg{talk} class makes no restrictions on the slide design whatsoever. The
  entire look and feel of the presentation can be defined by the user. The style
  definitions should be put in a separate sty file. Currently the package comes
  with only one set of pre-defined slide styles (sidebars.sty). Contributions
  from people who are artistically more gifted than me are more than welcome!
\end{abstract}
\newpage
\tableofcontents
%
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Installation and Requirements}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%
The \pkg{talk} class requires the packages \pkg{amsmath}, \pkg{pgf} version 1.18
or above, \pkg{multido} and \pkg{hyperref}. They can all be obtained from
\begin{quote}
  |http://www.ctan.org|.
\end{quote}

To install the \pkg{talk} class, you have to copy the files |talk.cls| and
|sidebars.sty| to a place where \LaTeX\ can find them.
%
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Using \pkg{talk}}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%
The usage of the \pkg{talk} class is almost independent of the chosen style
definitions. Therefore style definitions are most conveniently included through
separate \emph{style packages}. Currently \pkg{talk} comes with one such file
called |sidebars.sty|. (I hope that in the future the number of available style
packages will grow due to contributions from people that are artistically more
gifted than I am.) The issue of writing your own style definitions is discussed
in \mref{section}{sec:styles}. In this section we will see how to create a
presentation using the \pkg{talk} class and some ready-to-use style package like
|sidebars.sty|.

\begin{figure}
  \begin{quote}
    |\documentclass[|\var{options}|]{talk}|\\
    |\usepackage{|\var{style-def}|}|\\
    $\vdots$\\
    \txt{(more package inclusions)}\\
    $\vdots$\\
    |\title{|\var{title}|}|\\
    |\author{|\var{author}|}|\\
    |\date{|\var{date}|}|\\
    $\vdots$\\
    \txt{(global specifications required by \var{style-def})}\\
    $\vdots$\\
    |\begin{document}|\\
    |  \begin{slide}[|\var{slide-style}|]{|\var{slide-title}|}|\\
    |    |\txt{(body of first slide)}\\
    |  \end{slide}|\\
    |  \begin{notes}|\\
    |    |\txt{(notes on first slide)}\\
    |  \end{notes}|\\
    |  |$\vdots$\\
    |  |\txt{(more slides and notes)}\\
    |  |$\vdots$\\
    |  \section[|\var{short title}|]{|\var{long title}|}|\\
    |  |$\vdots$\\
    |  |\txt{(more slides and notes)}\\
    |  |$\vdots$\\
    |  \subsection[|\var{short title}|]{|\var{long title}|}|\\
    |  |$\vdots$\\
    |  |\txt{(more slides and notes)}\\
    |  |$\vdots$\\
    |  |\txt{(more sections and subsections)}\\
    |  |$\vdots$\\
    |\end{document}|
  \end{quote}
  \caption{\label{fig:structure} The general structure of a presentation
    \texttt{tex} file.}
\end{figure}
The general structure of a presentation |tex| file is shown in
\mref{figure}{fig:structure}. Note that you can structure your talk in the
usual way with |\section| and |\subsection| commands. How these commands are
handled depends on the loaded style package.
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Class Options}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
\label{ssec:options}
The \pkg{talk} class is loaded in the first line of the listing in
\mref{figure}{fig:structure}:
\begin{quote}
  |\documentclass[|\var{options}|]{talk}|
\end{quote}
The available options are
\begin{center}
  |screen|, |slides|, |notes|, |rotate| and |norotate|.
\end{center}
The \pkg{talk} class is built upon the |article| class, so it will pass all
unknown options to |article|. Thus, in principle, all options of the |article|
class can be used with the \pkg{talk} class as well. However, some options like
|twocolumn| etc.\ may lead to undesired results.

The options |screen|, |slides| and |notes| determine the \emph{mode}
in which your presentation is compiled. The options |rotate| and
|norotate| only take effect in the |slides| mode.

\DescribeMacro{screen}
Use the |screen| mode to create a screen presentation. With this option
the paper size is set to the slide size, so that your slides can be displayed
without white margins using the fullscreen mode of your favorite document
viewer.

\DescribeMacro{slides\\rotate\\norotate}
If you use the |slides| mode your presentation is prepared for printout on
transparencies. The slides are centered horizontally and vertically on normal
paper. The default paper size is A4, but you can change it by using any of the
paper size options of the |article| class. The options |rotate| and
|norotate| determine whether or not the slides are rotated by 90 degrees in
counterclockwise direction. By default rotation is enabled.
\DescribeMacro{\slidesmag}
In |slides| mode the slides can also be magnified. You can set the magnification
factor with
\begin{quote}
  |\slidesmag{|\var{factor}|}|.
\end{quote}

\DescribeMacro{notes}
The |notes| mode allows you to print personal notes for your presentation. In
this mode the slides are inserted in the flowing text, between your annotations.
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Style Packages and Slide Styles}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
Style definitions for the \pkg{talk} class are most conveniently included
through a separate \emph{style package}. Style packages can be included with the
usual |\usepackage| command:
\begin{quote}
  |\usepackage[|\var{package-options}|]{|\var{style-package}|}|.
\end{quote}
The available package options depend on the chosen style package. The principal
task of a \pkg{talk} style package is to set the width and height of the slides
and define a number of \emph{slide styles}. To identify the different slide
styles, the style package should give them \emph{style names} like |title|,
|framed|, |sidebar|, |plain|, etc.  \DescribeMacro{\slidestyle} To switch
between different slide styles you can use the command
\begin{quote}
  |\slidestyle{|\var{style-name}|}|.
\end{quote}
To change the slide style for only one slide you can pass a style name as an
optional argument to the |slide| or |multislide| environment.

\DescribeMacro{sidebars} The |sidebars| package has one option, |compress|,
which affects the way in which the table of contents is displayed in the
sidebar. It defines three slide styles called |plain|, |outline| and
|normal|. The |plain| style has no decorations at all and can be used for the
title page or for showing large pictures. The |outline| style is designed to
show the structure of your talk. Use it, for example, for the contents page.
The |normal| style should be used for all other slides. It has a sidebar showing
the structure of your talk. The current section is highlighted.

\DescribeMacro{\backgroundcolor}%
\DescribeMacro{\sidebarcolor}%
\DescribeMacro{\titlecolor}%
\DescribeMacro{\sidebartitlecolor}%
\DescribeMacro{\highlightcolor}%
Colours can be set with the commands listed in \mref{table}{tab:colorcmds}.
their syntax is
\begin{quote}
  |\|\var{color-command}|{|\var{red-value}|,|\var{green-value}|,|%
     \var{blue-value}|}|
\end{quote}
where \var{color-command} is one of the commands listed in
\mref{table}{tab:colorcmds} and \var{red-value}, \var{green-value} and
\var{blue-value} are numbers between 0 and 1.
\begin{table}
  \centering
  \begin{tabular}{lp{3in}}
    \hlx{hhv[1pt]}
    Command & Effect \\
    \hlx{hv[1pt]}
    |\backgroundcolor|   & sets the colour of the slide background\\
    |\sidebarcolor|      & sets the colour of the sidebar\\
    |\titlecolour|       & sets the colour of the slide title\\
    |\sidebartitlecolor| & sets the colour of the sidebar title\\
    |\highlightcolor|    & sets the colour of highlighted sections and
                           subsections in the sidebar\\
    \hlx{hh}
  \end{tabular}
  \caption{\label{tab:colorcmds}The colour commands of the \pkg{sidebars}
    package}
\end{table}
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Global Specifications}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
\DescribeMacro{\title}\DescribeMacro{\author}\DescribeMacro{\date}
Like the |article| class, \pkg{talk} allows you to specify the title, author
and date of your talk with the commands
\begin{quote}
  |\title[|\var{short-title}|]{|\var{title}|}|\\
  |\author[|\var{short-author}|]{|\var{author}|}|\\
  |\date{|\var{date}|}|
\end{quote}
In what context the short versions \var{short-title} and \var{short-author} are
used depends on the style package. The \pkg{sidebars} package displays
\var{short-title} and \var{short-author} in the side bar.  Other style packages
may also define addtitional commands, that allow you to specify additional
information like institute, logo, place where the talk was given etc.
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Environments}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
The \pkg{talk} class defines three environments: |slide|, |multislide| and
|notes|.  All typeset material in your talk should be enclosed in one of these
environments.

\DescribeMacro{slide}
The |slide| environment is the most important environment in the \pkg{talk}
class.  It allows you to typeset the contents of your slides. Its syntax is:
\begin{quote}
  |\begin{slide}[|\var{style-name}|]{|\var{slide-title}|}|\\
  |  |\txt{(slide body)}\\  |\end{slide}|
\end{quote}
The \var{style-name} argument is optional. It must be the name of one of the
slide styles defined in style package you have loaded. For the |sidebars|
package the available slide styles are |plain|, |outline| and |normal|. If no
\var{style-name} argument is given, \pkg{talk} uses the slide style specified in
the last call of the |\slidestyle| command.

\DescribeMacro{notes}
The |notes| environment allows you to include annotations to your slides in
the |tex| file. The contents of the |notes| environment are ignored if you
compile your presentation in the |screen| or |slides| mode.

\DescribeMacro{multislide}
The |multislide| environment can be used to create overlays. Its syntax is:
\begin{quote}
  |\begin{multislide}[|\var{style-name}|]{|\var{sub-slides}|}|%
                                        |{|\var{slide-title}|}|\\
  |  |\txt{(slide body)}\\
  |\end{multislide}|
\end{quote}
As for the |slide| environment the optional \var{style-name} argument and the
\var{slide-title} argument specify the slide style and the slide title. The
\var{sub-slides} argument has to be an integer number greater than zero. It
specifies the number of sub-slides, that the |multislide| environment will
generate. In the body of the |multislide| environment, you can use the commands
|\fromslide|, |\toslide| and |\onlyslide| to specify which material goes on
which sub-slide. 

\DescribeMacro{\fromslide}\DescribeMacro{\toslide}\DescribeMacro{\onlyslide}
The syntax of the commands |\fromslide|, |\toslide| and |\onlyslide| is:
\begin{quote}
  |\fromslide*{|$n$|}{|\var{material}|}|\\
  |\toslide*{|$n$|}{|\var{material}|}|\\
  |\onlyslide*{|$n$|}{|\var{material}|}|
\end{quote}
The |\fromslide*| command ignores \var{material} on the first $n-1$ sub-slides.
The |\toslide*| command ignores \var{material} on all sub-slides after the
$n$-th. The |\onlyslide*| command ignores \var{material} on all sub-slides exept
the $n$-th. If you use the unstarred commands |\fromslide|, |\toslide| and
|\onlyslide| the \var{material} is not ignored but made invisible, so that it
still uses up the space (pretty much like the |\phantom| command).
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Title and Contents Pages}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
\label{sec:toc}
Most talks begin with a title page showing the title of the talk, the name of
the speaker and possibly additional information like the date and place where
the talk is given, the institute of the speaker etc. For long talks you'll also
want to show the stucture of your talk at the beginning.

\DescribeMacro{\maketitle}\DescribeMacro{\tableofcontents}
Style packages for the \pkg{talk} class should therefore redefine the standard
\LaTeX\ commands |\maketitle| and |\tableofcontents| in such a way that they
produce suitable title and contents pages. These commands should be used in the
body of a slide environment. For example, with the |sidebars| style package
you would create title and contents pages by writing
\begin{quote}
  |\begin{slide}[plain]{}|\\
  |  \maketitle|\\
  |\end{slide}|
\end{quote}
and
\begin{quote}
  |\begin{slide}[outline]{Contents}|\\
  |  \tableofcontents|\\
  |\end{slide}|
\end{quote}

For some talks the table of contents may not fit on one slide. The \pkg{talk}
class cannot break material into multiple slides automatically, but it allows
you to split the table of contents manually.  To do this you can pass an
optional argument to the |\tableofcontents| command, which has the following
form:
\begin{quote}
  |\tableofcontents[|\var{fromsec}|.|\var{fromsubsec}%
                  |-|\var{tosec}|.|\var{tosubsec}|]|
\end{quote}
where \var{fromsec}, \var{fromsubsec}, \var{tosec} and \var{tosubsec} are
integer numbers. Their names are self-explaining. Note that the argument of
|\tableofcontents| must always have the form given above. If you wan to display
the sections 3 to 5 with all their subsections on one slide, you have to write
\begin{quote}
  |\tableofcontents[3.0-5.99]|
\end{quote}
(assuming that section 5 does not have more than 99 subsections).
%
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{The \pkg{talk} Class for Package Writers}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%
\label{sec:styles}
The entire look-and-feel of a \pkg{talk} presentation is determined by external
style packages. The macros provided by the \pkg{talk} class itself only take
care of more technical issues like
\begin{itemize}
  \item magnifying and positioning the slides on the paper,
  \item creating overlays,
  \item keeping a table of contents that is accessible on every slide,
  \item keeping a catalog of slide styles and allowing the user to switch
    between them.
\end{itemize}
To exploit these features, a style package writer needs to know some basic facts
about the inner workings of the \pkg{talk} class.
%
%
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\subsection{Mode Conditionals}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
As we have seen in \mref{section}{ssec:options} a \pkg{talk} presentation can be
compiled in three different modes: |slides|, |screen| and |notes|. To implement
mode-specific behaviour the \pkg{talk} class provides the following |if|
commands:
\DescribeMacro{\@ifslides}\DescribeMacro{\@ifscreen}\DescribeMacro{\@ifnotes}
\begin{quote}
  |\@ifslides{|\var{if-code}|}{|\var{else-code}|}|\\
  |\@ifscreen{|\var{if-code}|}{|\var{else-code}|}|\\
  |\@ifnotes{|\var{if-code}|}{|\var{else-code}|}|
\end{quote}
The \var{if-code} is executed if the talk is compiled in |slides|, |screen| or
|notes| mode, respectively, and the \var{else-code} is executed otherwise.
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Slide Dimensions}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
\DescribeMacro{\slidewidth}\DescribeMacro{\slideheight}
The width and height of the slides can be accessed through the |\slidewidth| and
|\slideheight| commands.
\DescribeMacro{\@slidesize}
However, to set the slide dimensions you should always use the command
\begin{quote}
  |\@slidesize{|\var{width}|}{|\var{height}|}|
\end{quote}
as it also adjusts the papersize and slide positioning.
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Global Specifications}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
\DescribeMacro{\@title}\DescribeMacro{\@author}\DescribeMacro{\@date}
The title, author and date set by the user with the |\title|, |\author| and
|\date| commands are stored in the macros |\@title|, |\@author| and |\@date|.
If you intend to display additional information like the speakers institute on
your slides you should define an |\institute| command in analogy to the commands
above:
\begin{quote}
  |\gdef\@institute{}|\\
  |\newcommand{\institute}[1]{\gdef\@institute{#1}}|
\end{quote}
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Counters}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
\DescribeMacro{slide\\subslide}
In addition to the standard counters of the |article| class, \pkg{talk} defines
the counters |slide| and |subslide|. The number of the current slide is stored
in |slide|. The slides of a |multislide| environment have the same |slide|
number and different |subslide| numbers.

\DescribeMacro{\theslide}\DescribeMacro{\thesubslide}%
The commands |\theslide| and |\thesubslide| can be used to print the slide or
subslide number, respectively. They are defined as
\begin{quote}
  |\newcommand{\theslide}{\arabic{slide}}|\\
  |\newcommand{\thesubslide}{\theslide.\arabic{subslide}}|
\end{quote}
You can redefine them to change the way the slide and subslide numbers
are displayed

\DescribeMacro{\theslidelabel}
For printing labels on your slides you should use the |\theslidelabel|
command. It calls |\theslide| when you are in a |slide| environment and
|\thesubslide| when you are in a |multislide| environment. 
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Style Definitions}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
To change the look-and-feel of your slides you have to redefine some or all of
the following commands:
\begin{quote}
  |\@makeslide|\\
  |\@makeslidebackground|\\
  |\@makeslidecontent|\\
  |\@makenotesslide|\\
  |\@maketocsection|\\
  |\@maketocsubsection|
\end{quote}
These commands will be called by the |slide|, |multislide| and |notes|
environments. Their exact meaning will be explained later on.
\DescribeMacro{\@newslidestyle}
To create a \emph{named} slide style, you have to wrap a |\@newslidestyle|
command around your definitions. A typical style definition takes the form
\begin{quote}
  |\@newslidestyle{|\var{style-name}|}{|\\
  |  \renewcommand{\@makeslide}{|\var{stuff}|}|\\
  |  \renewcommand{\@makeslidebackground}{|\var{stuff}|}|\\
  |  \renewcommand{\@makeslidecontent}{|\var{stuff}|}|\\
  |  \renewcommand{\@makenotesslide}{|\var{stuff}|}|\\
  |  \renewcommand{\@maketocsection}[3]{|\var{stuff}|}|\\
  |  \renewcommand{\@maketocsubsection}[4]{|\var{stuff}|}|\\
  |}|
\end{quote}

The |\@newslidestyle| command simply dumps its second argument into a macro
called |\pres@sty@|\var{style-name}. When the style is loaded
with |\slidestyle{|\var{style-name}|}| or with the optional argument of the
|slide| environment, all the |\@make|\ldots\ commands are reset to their default
definitions. Then the macro |\pres@sty@|\var{style-name} is executed.

Note that the |\renewcommand| calls in the second argument of |\@newslidestyle|
appear in the definition of the |\pres@sty@|\var{style-name} command. Therefore
the arguments of |\@maketocsection| and |\@maketocsubsection| have to be
referenced with double hashes, for example
\begin{quote}
  |\@newslidestyle{|\var{style-name}|}{|\\
  |  \renewcommand{\@maketocsection}[3]{Section ##1: ##3}|\\
  |}|  
\end{quote}
Single hashes would refer to the arguments of |\pres@sty@|\var{style-name}.
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Typesetting Slides}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
\DescribeMacro{\@slidetitle}\DescribeMacro{\@slidebody}
The |slide| and |multislide| environments store the slide title in the macro
|\@slidetitle| and the slide body in the macro |\@slidebody|. When you redefine
the various |\@make|\ldots\ commands you can therefore use |\@slidetitle| and
|\@slidebody| to insert the title and body of the current slide.

\DescribeMacro{\@makeslide} All the graphical wizardry in \pkg{talk} is done by
the \pkg{pgf} package.  To generate a slide the |slide| environment executes the
macro |\@makeslide| inside a |pgfpicture| environment. Before the call to
|\@makeslide| it executes several commands that set the bounding box of the
picture to a box of width |\slidewidth| and height |\slideheight| and scales and
rotates the picture in accordance with the on the compilation mode and class
options. The |\@makeslide| macro should therefore expand to a sequence of valid
\pkg{pgf} commands which draw the slide inside a box of width |\slidewidth| and
height |\slideheight|, with the origin located at the lower-left corner.
\DescribeMacro{\@slidebox} To obtain an LR box containing the properly
scaled and rotated slide you can use the |\@slidebox| macro.

\DescribeMacro{\@makenotesslide}
If you compile in the |notes| mode the |slide| and |multislide| environments
call |\@makenotesslide| to insert the current slide. By default the
|\@makenotesslide| command simply centers the |\@slidebox|
horizontally:
\begin{quote}
  |\newcommand{\@makenotesslide}{|\\
  |  \par\hspace*{\fill}\@slidebox\hspace*{\fill}\par|\\
  |}|
\end{quote}
You can change this behaviour by redefining the |\@makenotesslide| command. For
example, if you only want to print the title of each slide in your notes, you
should include something like
\begin{quote}
  |\renewcommand{\@makenotesslide}{|\\
  |  \begin{center}\textbf{\@slidetitle}\end{center}|\\
  |}|
\end{quote}
in your style definition.

To change the way the slides appear in the |screen| and |slides| mode you could
redefine the |\@makeslide| command. However, usually you'll want to draw the
slide background with \pkg{pgf} and then typeset the contents of the slide in a
minipage of width |\slidewidth| and height |\slideheight| placed on top of that
picture.
\DescribeMacro{\@makeslidebackground}\DescribeMacro{\@makeslidecontent}
Therefore the \pkg{talk} class provides two macros |\@makeslidebackground| and
|\@makeslidecontent| and a default definition for |\@makeslide| which does
exactly the above: It executes |\@makeslidebackground| inside a |pgfpicture|
environment, then covers the slide with a minipage of width |\slidewidth| and
height |\slideheight| and then executes the |\@makeslidecontent| inside the
minipage environment. Thus the |\@makeslidebackground| macro should expand to a
series of \pkg{pgf} commands that draw the background of the slide, with the
origin at the lower-left corner. The |\@makeslidecontent| macro should expand to
whatever you want to put in the minipage. Here, you start with the current point
in the upper left corner of the slide.

In this way \pkg{talk} gives you complete artistic freedom in the design of your
slides: It lets you define the macros that generate the slides while contents
like the slide title and body are previously stored in macros like
|\@slidetitle| and |\@slidebody|, so that you can insert them where you
like. For completeness we now summarise all commands yielding user defined
contents:
\begin{description}
  \item[\ccmd{slidetitle}] Title of the current slide.
  \item[\ccmd{slidebody}] Body of the current slide.
  \item[\texttt{\symbol{`\\}theslidelabel}] Label of the current slide. Shows
    the slide number in a |slide| environment and the slide and subslide number
    in a |multislide| environment.
  \item[\ccmd{title}] Title of the presentation.
  \item[\ccmd{shorttitle}] Short version of the title.
  \item[\ccmd{author}] Author of the presentation.
  \item[\ccmd{shortauthor}] Short version of the author.
  \item[\ccmd{date}] Date specified with the |\date| command (|\today| by
    default).
  \item[\ccmd{tableofcontents}] Prints the table of contents. See the next
    subsection for more information.
\end{description}
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{The Table of Contents}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
\DescribeMacro{\@tableofcontents}
The table of contents of your talk can be created with the |\@tableofcontents|
macro. Its name is slightly misleading because, in fact, it allows you to
display any kind of structure information on your slides. For example, you can
use it to print only the title of the current section. 

\DescribeMacro{\@maketocsection}\DescribeMacro{\@maketocsubsection}
The |\@tableofcontents| macro expands to a series of |\@maketocsection| and
|\@maketocsubsection| commands. By default these commands do nothing. You can
control the appearence of the table of contents by redefining them. Their syntax
is
\begin{quote}
  |\@maketocsection{|\var{section}|}{|\var{short-title}|}{|\var{long-title}|}|
  \\[\medskipamount]
  |\@maketocsubsection{|\var{section}|}{|\var{subsection}|}%|\\
  |                   {|\var{short-title}|}{|\var{long-title}|}|
\end{quote}
where \var{section} and \var{subsection} are integer numbers.

\DescribeMacro{\@ifcurrentsection}\DescribeMacro{\@ifcurrentsubsection}
Note that the |\@tableofcontents| macro always expands to the full list of
sections and subsections. To implement a special treatment for the
\emph{current} section or subsection you can use the |\@ifcurrentsection| and
|\@ifcurrentsubsection| commands. Their syntax is
\begin{quote}
  |\@ifcurrentsection{|\var{number}|}{|\var{if-code}|}{|\var{else-code}|}|\\
  |\@ifcurrentsubsection{|\var{number}|}{|\var{if-code}|}{|\var{else-code}|}|
\end{quote}
The \var{if-code} is executed if \var{number} matches the current section or
subsection, respectively, and \var{else-code} is executed otherwise. For
example, if you want to display the current section in the top left corner of
each slide, your style definition should look somewhat like
\begin{quote}
  |\newslidestyle{|\var{style-name}|}{|\\
  |  \renewcommand{\@maketocsection}[3]{|\\
  |    \@ifcurrentsection{##1}{##3}{}|\\
  |  }|\\
  |  \renewcommand{\@makeslidecontent}{|\\
  |    \@tableofcontents|\\
  |    |$\vdots$\\
  |  }|\\
  |  |$\vdots$\\
  |}|
\end{quote}

\DescribeMacro{\tableofcontents}
Most talks begin with an outline of the talk's contents. As a package writer you
should therefore provide a |\tableofcontents| command that allows the user to
print the full table of contents. (\pkg{talk} already defines the
|\tableofcontents| command, but it does nothing by default.) You can achieve
this, too, by redefining |\@maketocsection| and |\@maketocsubsection| and then
calling |\@tableofcontents|.

\DescribeMacro{\@ifinrange}
However, if the table of contents does not fit on one slide, the user should be
able to split it, using an optional range argument of the form shown in
\mref{section}{sec:toc}. It is the package writers task to implement this
feature, but the parsing of the range argument is done by the |\@ifinrange|
macro. Its syntax is
\begin{quote}
  |\@ifinrange{|\var{sec}|}{|\var{subsec}|}{|\var{range}|}{|\var{if-code}|}{|\var{else-code}|}|
\end{quote}
\var{sec} and \var{subsec} are section and subsection numbers and \var{range} is
a string of the form
\begin{quote}
  \var{fromsec}|.|\var{fromsubsec}|-|\var{tosec}|.|\var{tosubsec}
\end{quote}
The \var{if-code} is executed if the subsection specified by \var{sec} and
\var{subsec} lies in the range specified by \var{range}, the \var{else-code} is
executed otherwise.

A typical definition of the |\tableofcontents| command will therefore look as
follows:
\begin{quote}
  |\renewcommand{\tableofcontents}[1][0.0-99.99]{|\\
  |  \bgroup|\\
  |  \def\@maketocsection##1##2##3{|\\
  |    \@ifinrange{##1}{0}{#1}{|\\
  |      ##1.\space ##3\par|\\
  |    }{}|\\
  |  }|\\
  |  \def\@maketocsubsection##1##2##3##4{|\\
  |    \@ifinrange{##1}{##2}{#1}{|\\
  |      ##1.##2.\space ##3\par|\\
  |    }{}|\\
  |  }|\\
  |  \@tableofcontents|\\
  |  \egroup|\\
  |}|
\end{quote}
If you use grouping (|\bgroup| and |\egroup| or curly brackets) and plain \TeX\
definitions (|\def| instead of |\renewcommand|), as shown above, your
definitions remain local to the goup, so you don't have to worry about restoring
the original definitions of |\@maketocsection| and |\@maketocsubsection|. A more
sophisticated definition of the |\tableofcontents| command can be found in
|sidebars.sty|.
\newpage
%
%
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Contact}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%
For comments, bug reports, feature requests or submitting style packages please
email to
\begin{quote}
  |martin.wiebusch@gmx.net|
\end{quote}

\bigskip
\begin{flushright}
  Martin Wiebusch, \today
\end{flushright}
\end{document}