% seminardemo.tex,v 1.2 2002/11/14 20:46:00 hansfn Exp
%  
% TeXPower bundle - dynamic online presentations with LaTeX
% Copyright (C) 1999-2002 Stephan Lehmke
% 
% This program is free software; you can redistribute it and/or
% modify it under the terms of the GNU General Public License
% as published by the Free Software Foundation; either version 2
% of the License, or (at your option) any later version.
% 
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
% GNU General Public License for more details.
%
%-----------------------------------------------------------------------------------------------------------------
% File: seminardemo.tex
%
% Simple examples the for combining the seminar class with the dynamic features provided by the package texpower.sty. 
% 
%-----------------------------------------------------------------------------------------------------------------
% Autor: Stephan Lehmke <Stephan.Lehmke@cs.uni-dortmund.de>
%
% v0.0.1 Jun 02, 2000: First version for the pre-alpha release of TeXPower.
%

\documentclass{seminar}

% We need fixseminar for setting the page size correctly.

\usepackage{fixseminar}


%-----------------------------------------------------------------------------------------------------------------
% The texpower package is loaded. 
% We give the display option so dynamic features are enabled.
%
\usepackage[display]{texpower}


\begin{document}
\begin{slide}

\title{The \code{texpower} Package\\{\normalfont \texttt{seminar} Demo}}
\author{Stephan Lehmke\\\code{mailto:Stephan.Lehmke@cs.uni-dortmund.de}}
\maketitle

\newslide

\tableofcontents
\end{slide}

\begin{slide}
\centerslidesfalse
\section{A list environment}
  
% The \pause command `splits' the current page at the place it appears, producing two pages, one with everything which
% came before the \pause command, one containing this and additionally the stuff coming after \pause. When these pages
% are presented with acrobar reader in full screen mode (or any other viewer with this capability), the presentation
% will appear to `stop' at the point the \pause command was issued and `resume' in the moment the presenter switches to
% the next page.

\pause

% As \pause forces a paragraph break, it can not be used to separate a description label from the associated text. For
% this, we use the (very flexible) \stepwise command. Inside the argument of \stepwise, an arbitrary number of \step
% commands may occur. \stepwise will produce as many pages as there are \step commands, making the arguments of the
% \step commands appear ``one by one''.

\stepwise
{%
  \begin{description}
  \item[foo.] \step{bar.}
  \step{\item[baz.]} \step{qux.}
  \end{description}
  }



\end{slide}

\begin{slide}
\centerslidesfalse
\section{An aligned equation}

\pause

% Normally for \stepwise, if a \step is not yet active, its argument is ignored completely. This would disturb
% alignments, because the width changes with every new activated \step.
% \parstepwise is a variant of \stepwise where the argument of an inactive \step is put into a \phantom, leaving the
% proper amount of white space.

\parstepwise
{%
  % Using eqnarray with equation numbers here means all equation numbers will be visible from the outset, because only
  % the contents of the lines are `filled in'. See the full demo for an example of aligned equations where equation
  % numbers `appear'.
  \begin{eqnarray}
    %
    % When the argument of \step is put into a box (as it happens with \parstepwise), tabulators can not go in there. As
    % we want the equals sign to appear at the same time as the right side of the equation, we use \restep for the
    % latter. \restep is like \step, but it appears at the same time as the previous \step command.
    % 
    \sum_{i=1}^{n} i & \step{=} & \restep{1 + 2 + \cdots + (n-1) + n}\\
    %
                     & \step{=} & \restep{1 + n + 2 + (n-1) + \cdots}\\
    %
                     & \step{=} & \restep
                                  {% We can nest \step commands inside each other. The order of execution is just the
                                   % order of appearance, independent of nesting.
                                   % \switch is a variant of \step which takes two arguments and toggles between them on
                                   % activation. This way, we can make the \underbrace `appear'.
                                   % We insert a \vphantom in the first argument so that the equation numbers will be
                                   % placed correctly whether or not the underbrace is didplayed.
                                    \switch
                                    {%
                                      \vphantom{\underbrace{(1 + n) + \cdots + (1 + n)}_{\times\frac{n}{2}}}%
                                      (1 + n) + \cdots + (1 + n)%
                                      }
                                    {\underbrace{(1 + n) + \cdots + (1 + n)}_{\times\frac{n}{2}}}%
                                    }
                                  \\
    %
    % This is another nested application of \step. Note that the spacing of \cdot has to be corrected manually by
    % inserting {} left of it, because otherwise it would behave like a prefix operator.
    %
                     & \step{=} & \restep{\frac{(1 + n)\step{{}\cdot n}}{\restep{2}}}
  \end{eqnarray}
}




\end{slide}

\begin{slide}
\centerslidesfalse
\section{An array}

\stepwise
{% With arrays, beware of problems with automatic calculation of cell widths.
 % 
 % If you want all widths to be calculated automatically, you need to use \parstepwise, with the consequence that
 %   a) tabulators or newlines can not go into the argument of \step,
 %   b) the array `structure' (rules) will be completely visible right from the beginning.
 %   
 % If you want to use \stepwise for being able to build the `structure' (like \hilne's) dynamically (as done in the
 % following), you have to make sure that the cell widths are correct from the very first line, because otherwise the
 % array will expand horizontally, destroying the dynamic effect. This can be assured by
 %   a) using only p cells,
 %   b) making sure all the cells in the first line are at least as wide as the widest cell which will appear later. If
 %      you are using the calc package, this is easiest by putting \makebox[\widthof{widest entry}]{first entry} into
 %      the first cell. Otherwise, you can use \settowidth.
 %      
  \begin{displaymath}
    \begin{array}{rrrrr}
      \step
      {%
            n &        \log n        &        n\log n       & \lefteqn{n^2}\phantom{25} & \lefteqn{2^n}\phantom{32} \\
        \hline%
        }%
      \step{0 &} \step{\textrm{---}  &} \step{\textrm{---}  &} \step{0                  &} \step{1                  \\}%
      \step{1 &} \step{0\phantom{.6} &} \step{0\phantom{.8} &} \step{1                  &} \step{2                  \\}%
      \step{2 &} \step{1\phantom{.6} &} \step{2\phantom{.8} &} \step{4                  &} \step{4                  \\}%
      \step{3 &} \step{1.6           &} \step{4.8           &} \step{9                  &} \step{8                  \\}%
      \step{4 &} \step{2\phantom{.6} &} \step{8\phantom{.8} &} \step{16                 &} \step{16                 \\}%
      \step{5 &} \step{2.3           &} \step{11.6          &} \step{25                 &} \step{32                   }%
    \end{array}
  \end{displaymath}
}




\end{slide}

\begin{slide}
\centerslidesfalse
\section{A picture}

\pause

\begin{center}%
  \stepwise
  {%
    \setlength{\unitlength}{1.5\semcm}%
    \delimitershortfall-1sp% Just for the nested braces
    \begin{picture}(14,2)
      \put(0,1){\vector(1,0){1}}
      \put(0.5,0.5){\makebox(0,0){\small $x(t)$}}
      \put(13,1){\vector(1,0){1}}
      \put(13.5,0.5){\makebox(0,0){\small $y(t)$}}
      \step
      {
        \put(1,1){\line(3,2){1.5}}
        \put(1,1){\line(3,-2){1.5}}
        \put(2.5,0){\line(0,1){2}}
        \put(2,1){\makebox(0,0){\large $\varphi$}}
        }
      \step
      {
        \put(2.5,1){\vector(1,0){3.5}}
        \put(4.25,0.5){\makebox(0,0){\small $F_t = \varphi\left(x(t)\right)$}}
        }
      \step
      {
        \put(6,0){\framebox(2,2){\large $\Phi$}}
        }
      \step
      {
        \put(8,1){\vector(1,0){3.5}}
        %
        % Here, we find another nested use of \step inside \step.
        % \bstep is a variant of \step which _always_ puts its argument into a box for leaving the correct amount of
        % white space. We cannot use \parstepwise here because \put can't go into a box. Hence, just using \step for
        % building the nested formula on the next line would give the wrong size for the nested braces.
        % 
        \put(9.75,0.5){\makebox(0,0){\footnotesize $G_t = \Phi\left(\bstep{\varphi\left(\bstep{x(t)}\right)}\right)$}}
        }
      \step
      {
        \put(13,1){\line(-3,2){1.5}}
        \put(13,1){\line(-3,-2){1.5}}
        \put(11.5,0){\line(0,1){2}}
        \put(12,1){\makebox(0,0){\large $\delta$}}
        }
    \end{picture}%
    }%
\end{center}%
\end{slide}
\end{document}



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