# In a beamer slide highlight a region of an image with a rectangle overlay

I have a slide with a figure in it. I want to draw a rounded corner rectangle overtop part of a figure to highlight that section. Bonus points if you can draw two rounded rectangles as overlays that appear one at a time.

\documentclass{beamer}
\usepackage[T1]{fontenc}

\begin{document}

\begin{frame}
\frametitle{ESR1}

\begin{center}
Functional analysis
\end{center}

\begin{center}
\includegraphics[width=1\textheight]{some_image.jpg}
\end{center}
\end{frame}
\end{document}


(Note: I removed most of the unnecessary code in the example code, so the theme in the picture doesn't match with the default one in the example code anymore. --Caramdir)

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Bonus kharma of course – denilw Jan 13 '11 at 21:07

You can include the picture into a TikZ node and then draw some rectangles over it. For example,

\documentclass{beamer}
\usepackage[T1]{fontenc}
\usepackage{tikz}

\begin{document}

\begin{frame}
\frametitle{ESR1}

\begin{center}
Functional analysis
\end{center}

\begin{center}
\begin{tikzpicture}
\node[anchor=south west,inner sep=0] at (0,0) {\includegraphics[width=1\textheight]{some_image.jpg}};
\draw<1>[red,ultra thick,rounded corners] (1.6,1) rectangle (\textheight-1cm,5);
\draw<2>[red,ultra thick,rounded corners] (5.7,4.1) rectangle (7.5,4.9);
\end{tikzpicture}
\end{center}
\end{frame}
\end{document}


with a picture from Wikipedia as some_image.jpg gives the two slides

Note the \node[anchor=south west,inner sep=0] at (0,0) {\includegraphics{...}}; line. This adds the picture so that the lower left corner is at the origin of the TikZ coordinate system. Section 14.6 “Rounding Corners” of the TikZ manual (v2.10) tells you how you can change the corner rounding.

Btw, do you really mean width=1\textheight?

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Accepted fastest solution. Testing now. – denilw Jan 13 '11 at 23:00
I think the text's height is the limiting factor for this image when the title is taken into account. I may be wrong, maybe that command doesn't even consider the title. – denilw Jan 13 '11 at 23:03
width=1\textheight sets the width of the picture to the height of the text. – Caramdir Jan 13 '11 at 23:09
@denilw, you should test before accepting... – Caramdir Jan 13 '11 at 23:10

Damn you Caramdir, four minutes too late!

Anyway, here's what I came up with. Caramdir's is at least as good, but mine is a bit closer to your syntax, maybe...

\documentclass[english,ignorenonframetext,table]{beamer}
\usepackage[T1]{fontenc}
\usepackage[latin9]{inputenc}
\setcounter{secnumdepth}{3}
\setcounter{tocdepth}{3}
\usepackage{graphicx}

\makeatletter

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% LyX specific LaTeX commands.
%% A simple dot to overcome graphicx limitations
\newcommand{\lyxdot}{.}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Textclass specific LaTeX commands.
% this default might be overridden by plain title style
\newcommand\makebeamertitle{\frame{\maketitle}}%
\AtBeginDocument{
\let\origtableofcontents=\tableofcontents
\def\tableofcontents{\@ifnextchar[{\origtableofcontents}{\gobbletableofcontents}}
\def\gobbletableofcontents#1{\origtableofcontents}
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% User specified LaTeX commands.
\usepackage{xcolor}
\usepackage{listings}
\usetheme{Frankfurt} %Warsaw
\usecolortheme{albatross}
\setbeamercovered{transparent}

\newcommand{\tformating}{
\definecolor{darkPurple}{rgb}{0.101960784313725,0,0.2}
\definecolor{purple}{rgb}{0.2,0,0.4}
\definecolor{lightPurple}{rgb}{0.4,0,0.4}
\rowcolors[]{1}{darkPurple}{purple}
\small
}

\usepackage{tikz,overpic}
\usetikzlibrary{fit,shapes.misc}

\makeatother

\usepackage{babel}

\begin{document}
\begin{frame}

\frametitle{ESR1}

\begin{center}
Functional analysis
\par\end{center}

\begin{center}
\only<1>{\begin{overpic}[width=1\textheight]{some_image.jpg}
\end{overpic}}%
\only<2>{\begin{overpic}[width=1\textheight]{some_image.jpg}
\put(40,38){\tikz \draw[red,thick,rounded corners] (0,0) rectangle (5,1.2);}
\end{overpic}}%
\only<3>{\begin{overpic}[width=1\textheight]{some_image.jpg}
\put(40,38){\tikz \draw[red,thick,rounded corners] (0,0) rectangle (5,1.2);}
\put(0,14){\tikz \draw[red,thick,rounded corners] (0,0) rectangle (3.5,1.2);}
\end{overpic}}%
\par\end{center}

\end{frame}
\end{document}


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Some of my code came from your earlier code, which was changed. Grr! ;) – frabjous Jan 13 '11 at 22:22
But you have an animated gif! – Caramdir Jan 13 '11 at 22:25
Yep. Does that get me any bonus points? – frabjous Jan 13 '11 at 22:28
I'm very impressed by the animated gif. Bonus kharma and +1 for you. – denilw Jan 13 '11 at 23:00
Solution works. – denilw Jan 13 '11 at 23:52

# NOTES

Because I use PSTricks, the image is in eps format. My compilation steps are

1. latex.exe to convert .tex to .dvi.
2. dvips.exe to convert .dvi to .ps.
3. ps2pdf.exe to convert .ps to .pdf.

\documentclass{beamer}
\usepackage[T1]{fontenc}
\usepackage{pstricks}

\newdimen\ImageW
\ImageW=8cm

\newdimen\ImageH
\ImageH=6cm

\begin{document}

\begin{frame}[t]{ESR1}

\begin{center}
Functional analysis
\end{center}

\begin{center}
\pspicture(\ImageW,\ImageH)
\rput(0.5\ImageW,0.5\ImageH){\includegraphics[width=\ImageW]{pitfall}}
%\psgrid%turn on or off for navigational purpose during development
\pause
\psset{linecolor=red,linewidth=2pt,framearc=0.5}
\psframe(5.2,3.8)(6.4,5.6)\pause
\psframe(2.7,0)(4.5,1)
\endpspicture
\end{center}

\end{frame}
\end{document}

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