\documentclass[12pt]{report}
\topmargin -0.5in
\textheight 25cm
\usepackage{epsfig}
\begin{document}
\subsection*{{\sc Prosper:} \LaTeX-based computer presentations}
 In many branches of science and engineering,  presentation
software (usually Microsoft's Powerpoint), has become a popular
tool for the delivery of research talks. Increasingly, 
such software is also being used in undergraduate 
teaching. If used properly, presentation software combines the
advantages of traditional `chalk \& talk'--based teaching (arguments
can be developed step-by-step; sections of text can be erased while
others are kept `on the blackboard') with the benefits of 
computer-generated OHP slides (ensuring an attractive appearance 
regardless of one's handwriting). It also adds the ability to incorporate 
computer-generated graphics and animations.

 Recently *** have developed a new document class
which allows the creation of computer-based presentations
in \LaTeX. The {\sc Prosper} document class is based on the {\tt
slides} class 
and makes extensive use of the `overlay' technique to  
build up pages step-by-step. Two files are required: The file 
`prosper.cls' which is available from {\tt \small http://www.***} and a 
style file which defines background colours, the geometry of any 
frames which border the page, the default font sizes for text and 
headers, etc. The webpage provides a number of suitable style files 
which can easily be modified to suit one's own needs.

  The way in which the appearance (and disappearance) of certain sections
of text on the screen is controlled is illustrated in the following
example:
{\small
\begin{verbatim} 
\overlays{3}{
\begin{slide}
This text is visible throughout. 
\onlySlide[3]{This text only appears on slide three.}
\untilSlide[2]{This text appears until slide two.}
\fromSlide[2]{This text appears from slide two.}
\end{slide}}
\end{verbatim} 
In the above example, the text specified in the arguments 
remains displayed at its original position even if the space `above'
it becomes available subsequently. An alternative form of
the three commands (e.g. {\tt $\backslash$fromSlide*[n]\{\}}) reformats 
the page to fill any gaps that appear when material is removed.
Many different  transitions between slides (replace, dissolve, glitter,...) 
are available.


 After compiling the \LaTeX \ source code, the dvi file is translated 
***WHAT EXACTLY IS THE BEST WAY TO DO THIS???****
into a pdf file which can then be displayed by the (freely available) 
{\sc acrobat} reader. Within acroread $<$Ctrl l$>$ changes the display to full 
screen mode; the speaker then navigates through the document with the 
arrow keys. Graphics can be incorporated with standard  \LaTeX \
packages such as {\tt epsfig} or {\tt graphics}. Animations cannot be directly
incoporated into a document but the {\tt \small $\backslash$href\{\}} command
allows external programs to be spawned from within the acroread 
session. For instance the command
{\small

***ANDREW TO PROVIDE THE REAL STORY...***
\begin{verbatim} 
\href{Start animation.}{/usr/local/bin/xanim WonderfulAnimation.avi} 
\end{verbatim}
}
\noindent
causes the multimedia player xanim to display an avi file when the user
clicks on the relevant section of text in acroread.  
An example, illustrating the on-screen manipulation of a fairly 
complex equation and the use of associated graphics can be found at 
{\tt \small http://www.maths.man.ac.uk/\ $\tilde{\,}$~mheil/Prosper}. 

  When we first used {\sc Prosper}, we were amazed how easy it was to convert 
existing \LaTeX-generated slides into electronic presentations. We
have now used {\sc Prosper} for many research presentations and
occassionally for undergraduate teaching. The following points
might be useful for newcomers to computer-based presentations:
\begin{itemize}
\item LCD projectors are now widely available at conferences 
and incompatabilities between laptops and the projectors
tend to be rare(r). Nevertheless, we still prepare `backup' 
OHP slides in case of any hardware problems.

\item One drawback of any computer-based presentation is that
it is impossible to see the next slide before it appears on the screen.
To ensure a smooth talk, it is vital to remember the sequence of 
one's slides well. We (and a few other speakers whose talks we have
attended) have occassionally been surprised by the appearance of 
an `unexpected' slide.

\item Many speakers use Post-It notes to attach brief notes to their
OHP transparencies. We tend to use the {\tt $\backslash$onlyslide\{\}} 
command to briefly display any such notes (in a smaller fontsize) 
on the screen. 

\item Most laptops have three display modes which direct the output 
either (i) only to the computer screen, (ii) only to the LCD
projector, or (iii) to both. Option (ii) prevents the speaker
from pointing at the laptop screen! 

\item It is very easy to customise the style files to include 
logos, frames and colourful backgrounds. However, it is important to 
remember that graphics can be distracting and that some 
backgrounds strongly reduce the readability of the text.
For maximum contrast, we prefer black text on a white background and 
tend to use colour only to highlight important sections 
of the text and the equations. 


\end{itemize}
To summarise, we feel that the authors of the {\sc Prosper} document
class have created an extremely useful tool which we expect to be
become very popular within the mathematical community. 

  



\end{document}






































































































