When preparing slides with \documentclass[letterpaper]{seminar}
one can use the following macros to gradually introduce a slide:

(1)

\SlideContent
 \cntdel \sldendmar

together with

\SlideLayout

and

(2)

\grad    \alternativeg  \endg


To use these tools, type

\input SlideTools.tex

in your LaTeX file before \begin{document}.


Below there is a short description of what these macros do.

In order for the contents of a slide not to move as you introduce
new components put 

\centerslidesfalse

before \begin{document}.

\centerslidesfalse turns off the vertical balancing of slides. If
you want this feature on for a particular slide put
\centerslidestrue
right after that slide's \begin{slide}


-------------------------------------------------------------

1- \SlideContent and SlideLayout:
Put \SlideContent after \begin{slide} to define the components
that will make up your slide.  Here is an example:

\begin{slide}
\SlideContent

This is an example

%whatever latex code you want to 
%put in this component

\cntdel

$$x= 7$$
%whatever latex code you want to 
%put in this component

\cntdel

$$x = 3 +4$$
%whatever latex code you want to 
%put in this component

\sldendmar

% I call the latex code between the delimeters
% \cntdel "Slide component".
%With \SlideContent you can define as
%many components as you want by delimiting
% them with \cntdel.
%\sldendmar marks the end of component definition.



Once you defined your components with \SlideContent
use

\SlideLayout 

to specify how you want the components to be laid out and to 
be gradually introduced. For example:

\SlideLayout(1|1,2|1,2,3)

first shows the first component, then first and second and
then all of them. Whereas

\SlideLayout(1|1,2|1,3)

first shows the first component, then first and the second
and finally first and the third. each specification between
vertical bars is realized as a seperate slide. You can use
whichever components you want to specify a layout. For example
the following is also a legitimate layout specification:

\SlideLayout(3,1|3,2|1|1,2,3|2)



after you use \SlideLayout, end the slide with 
\end{slide}


--------------------------------------------------------


2- \grad   \alternativeg    \endg 


You can also use \grad \alternativeg \endg to gradually
introduce latex code within a component. Here is an example.
Suppose you type the following within  component 2 while
using \SlideContent:


\gradg
$\alpha=\beta+\beta$
%other latex code
\alternativeg
$\alpha=2\beta$
%other latex code
\endg


When \SlideLayout lays out component 2 for the first time, 
it will first show the latex code between \gradg and \alternativeg. 
then it will show the latex code between \alternativeg and \endg. 
If component 2 is used in the rest of the layout specification SlideLayout
will only show the alternative latex code, that is the code between
\alternativeg and \endg.