#4 enumste and itemstep environment

[Anonymous]

I wanted to display an itemstep environment on a slide,
on which I displayed before some pictures with
onlySlides/fromSlides. With the original environment
this is not possible. So I added a optional parameter
to the itemstep environment, to set the slide (overlay)
number from which the first item is displayed.

This can be used as follows:

\overlays{3}{
\begin{slide}{Test Slide}
\onlySlide*{1}{\includegraphics{./test.eps}}
\fromSlide{2}{\includegraphics{./test2.eps}}
\begin{itemstep}[3] %optional parameter
\item My first item ...
\item My second item ...
\end{itemstep}
\end{slide}
}

The new environment (wich is full back compatible to
the old environment) looks as follows:

% itemstep : itemize environment with step-by-step
%displaying
% The optional parameter determines the slide (overlay)
%on which the first
% item is displayed.
% Warning: no nesting allowed
\newcounter{item@step}
\newenvironment{itemstep}[1][1]{%
\setcounter{item@step}{#1}
\addtocounter{item@step}{-1}
\let\old@item=\item
\begin{itemize}%

\def\item{\StepCounter{item@step}%
\FromSlide{\theitem@step}\old@item}
}{\end{itemize}\setcounter{item@step}{0}}

Additionally, to use the same for an enumerate, I added
the environment enumstep:

% enumstep : enumeration environment with step-by-step
displaying
% The optional parameter determines the slide (overlay)
on which the first
% item is displayed.
% Warning: no nesting allowed
\newcounter{enum@step}
\newenvironment{enumstep}[1][1]{%
\setcounter{enum@step}{#1}
\addtocounter{enum@step}{-1}
\let\old@item=\item
\begin{enumerate}%

\def\item{\StepCounter{enum@step}%
\FromSlide{\theenum@step}\old@item}
}{\end{enumerate}\setcounter{enum@step}{0}}