# Zooming in and highlighting part of picture

In a beamer presentation, is it possible to zoom in on an image to make it full screen and if possible to highlight (something like illuminating a part of picture by bright light while other areas of the slide fade ) the desired location on the image?

• tikz spy should be, what you are looking for. See here for example: tex.stackexchange.com/questions/59705/… – schmendrich Jul 30 '13 at 11:26
• Not exactly what you want but take a look at framezoom command in beameruserguide. – Ignasi Jul 30 '13 at 11:37

This is a modification of samcarter's answer. As it stands, the zoomed image will not occupy the whole frame if a theme which installs header/footer is used or if the frame has a title. However, the beamer documentation explains how to overcome this (page 109):

\documentclass{beamer}
\usetheme{Warsaw}

\begin{document}

\begin{frame}<1>[label=zooms]
\frametitle<1>{Example Grid}
\framezoom<1><2>[border](0cm,0cm)(2cm,1.5cm)
\framezoom<1><3>[border](1cm,3cm)(2cm,1.5cm)
\framezoom<1><4>[border](3cm,2cm)(3cm,2cm)
\pgfimage[height=8cm]{example-grid-100x100bp.pdf}
\end{frame}
\againframe<2->[plain]{zooms}

\end{document}


# EDIT

You could use something like the fadings library to highlight a particular area of the slide if you wished. This isn't quite what you wanted, I know, but perhaps you can modify it to provide something suitably useful:

\documentclass{beamer}
\usetheme{Warsaw}
\usepackage{tikz}
\begin{document}

\begin{frame}<1>[label=zooms]
\frametitle<1>{Example Grid}
\framezoom<1><2>[border](1cm,3cm)(2cm,1.5cm)
\framezoom<1><3>[border](3cm,2cm)(3cm,2cm)
\begin{tikzpicture}[outer sep=0, inner sep=0]
\only<2>{%
}
\only<3>{%
}
\begin{scope}[on background layer]
\node at (0,0) {\includegraphics[height=8cm]{example-grid-100x100bp.pdf}};
\end{scope}
\end{tikzpicture}
\end{frame}
\againframe<2->[plain]{zooms}

\end{document}


Following an example in http://de.slideshare.net/mustainmtn/beamer-guide-by-kijoo-kim-aka-daisyweb, p.32 this can easily be done:

\documentclass{beamer}

\begin{document}

\begin{frame}
\framezoom<1><2>[border](0.5cm,0.5cm)(2cm,1.5cm) \framezoom<1><3>[border](1cm,3cm)(2cm,1.5cm)
\framezoom<1><4>[border](3cm,2cm)(2cm,2cm)
\pgfimage[height=6cm]{example-grid-100x100bp.pdf}
\end{frame}

\end{document}


• (+1) for \framezoom but that won't use the whole screen if the theme inserts header/footer or if there is a frame title. I've added an answer based on yours which should use the whole screen even in these other cases. – cfr Jul 1 '14 at 1:59