# TikZ in itemize

I want to make a frame transition as seen here. http://www.slideshare.net/thomasmach/hierarchical-matrices-concept-application-and-eigenvalues i.e. from

to

Move from slide 8/67 to 9/67. I am wondering what is the right and the best way to go about.

EDIT: As an example, to the slide below I want to add the arrows and make it look like the slide 9/67 as seen here.

    \documentclass{beamer} %
\usetheme{CambridgeUS}
\usepackage[latin1]{inputenc}
\usefonttheme{professionalfonts}
\usepackage{times}
\usepackage{tikz}
\usepackage{amsmath}
\usepackage{verbatim}
\usetikzlibrary{arrows,shapes}

\author{Author}
\title{Presentation title}

\begin{document}
\section{Concept}
\subsection{Dense matrices}
\begin{frame}{Dense matrices}
\begin{itemize}
\item Dense matrix
$$A = \begin{bmatrix} a_{11} & a_{12} & a_{13} & \cdots & a_{1n}\\ a_{21} & a_{22} & a_{23} & \cdots & a_{2n}\\ a_{31} & a_{32} & a_{33} & \cdots & a_{3n}\\ \vdots & \vdots & \vdots & \ddots & \vdots\\ a_{n1} & a_{n2} & a_{n3} & \cdots & a_{nn} \end{bmatrix}$$
\end{itemize}

\begin{itemize}
\item
$n^2$ entries in the storage.
\item
Matrix vector product: $Ax$ costs $\mathcal{O}(n^2)$.
\item
Matrix matrix product: $AB$ costs $\mathcal{O}(n^\delta)$ flops, $\delta \geq 2.3727$ practically $\mathcal{O}(n^3)$.
\item
Matrix factorizations: LU, QR, SVD etc costs $\mathcal{O}(n^3)$.
\end{itemize}

\end{frame}
\end{document}

-
Looks like a classic use of a \tikzmark type of solution. It would be helpful if you composed a fully compilable MWE including \documentclass and the appropriate packages that sets up the problem. While solving problems is fun, setting them up is not. I personally know very little about beamer but if I had something to start with I could certainly enhance it with a \tikzmark to show you how to obtain the desired result. –  Peter Grill Oct 14 '12 at 3:59
Thanks Peter. I have added an example code. –  user17762 Oct 14 '12 at 4:17
Great. Can you add the second frame as well. –  Peter Grill Oct 14 '12 at 4:19
@PeterGrill Well... Thats what I do not know. –  user17762 Oct 14 '12 at 4:23

Here's one possibility: I defined a \mybox command with three mandatory arguments:

\mybox{<title>}{<text>}{<position>}


This command writes <text> in a nice framed box with a <title> at the desired position. Each box will be internally named as box-<number>. Then, \tikzmark is used to place marks in the points where the arrows will end.

\documentclass{beamer}
\usetheme{CambridgeUS}
\usepackage{tikz}

\definecolor{myred}{RGB}{166,0,0}
\newcounter{boxes}

\newcommand\mybox[3]{%
\stepcounter{boxes}%
\begin{tikzpicture}[remember picture,overlay]
\node[rectangle,rounded corners,line width=1pt,
draw=myred,fill=myred!30,text height=20pt,
text depth=11pt,align=left,fill opacity=0.7,text opacity=1]
(box-\theboxes) at #3 {#2};
\node[rectangle,rounded corners,fill=myred!90,
font={\Large\color{white}},anchor=west]
at ([xshift=10pt,]box-\theboxes.north west) {#1};
\end{tikzpicture}%
}

\newcommand\tikzmark[1]{%
\tikz[remember picture,overlay] \node (#1) {};}

\begin{document}

\begin{frame}
$\begin{bmatrix} 1 & 0 & 0 & 1 \\ 1 & 0 & 0 & 1 \\ 1 & 0 & 0 & 1 \\ 1 & 0 & 0 & 1 \\ \end{bmatrix}$

\begin{itemize}
\item First item.
\item Second item.
\item Third and some $\mathcal{O}(\tikzmark{a}n^2)$ flo\tikzmark{b}ps item.
\item Fourth item.
\item Fifth item.
\end{itemize}

\onslide<2>{%
\mybox{Landau symbol}{There is a constant $c$ such that $Ax$ costs no more than $cn^2$ flops.}{(0.5\textwidth,0.63\textheight)}
\mybox{Flops}{1 flop ${} = (\alpha\beta +\gamma \rightarrow \gamma)$}{(0.79\textwidth,0.4\textheight)}

\begin{tikzpicture}[remember picture,overlay]
\draw[line width=1pt,myred,->,shorten >= 6pt] (box-1.south) to[out=270,in=90] (a);
\draw[line width=1pt,myred,->,shorten >= 5pt] (box-2.west) to[out=180,in=90] (b);
\end{tikzpicture}%
}
\end{frame}

\end{document}


-
Thanks @Gonzalo –  user17762 Oct 14 '12 at 4:36
2 seconds!!!!!! I think my comments gave you the edge you needed to get this done faster. :-) –  Peter Grill Oct 14 '12 at 4:38
Is there a way I can make the blue boxes a bit transparent, as shown on the slides? –  user17762 Oct 14 '12 at 4:38
Thanks Gonzalo and Peter. Much appreciated. –  user17762 Oct 14 '12 at 4:41
@PeterGrill when I saw your first comment I knew I had to type really fast ;-) –  Gonzalo Medina Oct 14 '12 at 4:51