[Tex/LaTex] Beamer: highlighting text with colored background through which surrounding text can be seen

beamerhighlightingtcolorbox

On some slides I'd like to highlight some text by using a colored background, like so:
text with some words highlighted

I've exaggerated the width of the border around the text in this example to indicate the effect I want.

I produced this example manually. I'd like to have a macro \highlighton so that I can produce the effect by writing \highlighton<1>{`to protrude out'}. The wonderful package tcolorbox provides macros that almost do the trick. Here's an example.

\documentclass{beamer}
\usepackage{etex}
\setbeamertemplate{navigation symbols}{}
\usepackage{tcolorbox}
\tcbuselibrary{skins}
\usepackage{times}
\def\highlighton<#1>#2{%
  \alt<#1>{\tcbox[enhanced,boxrule=0pt,colback=red!50,interior style=
  {opacity=0.7},frame style={opacity=0.5},nobeforeafter,tcbox raise base,shrink
  tight,extrude by=5mm]{#2}}{#2}%
}

\begin{document}
\begin{frame}

\textbf{Extrude}, \textit{v}.\ trans. \textbf{1}.\ To thrust (a person) out or forth;
to urge or force out; to expel.  \textbf{a}.\ with obj.\ a person.  \textbf{b}.\ with
obj.\ a material thing; in mod.\ use esp.\ to exclude (an embryo, ova, etc.). Also 
occas.\ with sense \highlighton<1>{`to protrude out'}.  \textbf{c}. with an immaterial 
thing as obj. \textbf{d}.\ To shape (metals, plastics, etc.)\ by forcing them through 
dies. \textbf{2}.\ intr.\ for refl. To protrude out. rare.

\pause

\end{frame}
\end{document}

This code (in which extrude by 5mm generates the border) produces the following output. Text before the highlighted text is "dimmed", but text after the highlighted text isn't. Is there a way to produce exactly the effect I want?

enter image description here

Best Answer

My answer is using the same idea as Claudio Fiandrino did. But it uses tcolorbox (v2.61) and you may use as many highlights as you want on a page.

\documentclass{beamer}
\usepackage{etex}
\setbeamertemplate{navigation symbols}{}
\usepackage{tcolorbox}
\tcbuselibrary{skins}
\usepackage{times}
\def\remember#1#2{%
  \tcbox[enhanced,remember as={#1},frame hidden,interior hidden,boxrule=0pt,nobeforeafter,
    tcbox raise base,shrink tight]{#2}%
  \pgfkeyssetvalue{/myremember/#1}{#2}%
}
\def\highlighton<#1>#2{%
  \alt<#1>{\tikz[overlay,remember picture]\node at (#2){%
  \tcbox[enhanced,boxrule=0pt,colback=red!50,interior style={opacity=0.7},
         frame style={opacity=0.5},nobeforeafter,tcbox raise base,shrink tight,
         extrude by=5mm]{\pgfkeysvalueof{/myremember/#2}}};}{}%
}

\begin{document}
\begin{frame}

\textbf{Extrude}, \textit{v}.\ trans. \textbf{1}.\ To thrust (a person) out or forth;
to urge or force out; to expel.  \textbf{a}.\ with obj.\ a person.  \textbf{b}.\ with
obj.\ a material thing; in mod.\ use esp.\ to exclude (an embryo, ova, etc.). Also
occas.\ with sense \remember{protrude}{`to protrude out'}.  \textbf{c}. with an immaterial
thing as obj. \textbf{d}.\ To shape \remember{etc}{(metals, plastics, etc.)}\ by forcing them through
dies. \textbf{2}.\ intr.\ for refl. To protrude out. rare.%
\highlighton<2>{protrude}
\highlighton<3>{etc}

\pause
\end{frame}
\end{document}

enter image description here

Related Solutions

[Tex/LaTex] Beamer: highlighting aligned math with overlay

By following the method shown in Background coloring with overlay specification in algorithm2e + beamer package, it is possible to build this MWE:

\documentclass{beamer}
\usepackage{amsmath,amssymb}
\usepackage{tikz}
\usetikzlibrary{fit,calc}

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

\definecolor{mybrown}{RGB}{255,218,195}
\definecolor{myframe}{RGB}{197,122,195}

\usetheme{Copenhagen}

\begin{document}

\section{Mysection}
\subsection{A subsection}
\begin{frame}{The equations}
\begin{block}{}
 \begin{align}
      \tikzmark{a}a_i\tikzmark{b} + b_j = 10 & \forall i\in I, j\in J \\
      \tikzmark{e}c_j + d_j + \tikzmark{c}a_i\tikzmark{d} >= 30 & \forall i\in I, j\in J\tikzmark{f}
 \end{align}

\begin{tikzpicture}[remember picture,overlay]
\coordinate (aa) at ($(a)+(0,0.25)$);
\coordinate (bb) at ($(b)+(0,0)$);
\node<1>[draw=myframe,line width=1pt,fill=mybrown,opacity=0.4,rectangle,rounded corners,fit=(aa) (bb)] {};
\coordinate (cc) at ($(c)+(0,0.25)$);
\coordinate (dd) at ($(d)+(0,0)$);
\node<1>[draw=myframe,line width=1pt,fill=mybrown,opacity=0.4,rectangle,rounded corners,fit=(cc) (dd)] {};
\coordinate (ee) at ($(e)+(0,0.25)$);
\coordinate (ff) at ($(f)+(0,-0.25)$);
\node<2>[draw=myframe,line width=1pt,fill=mybrown,opacity=0.4,rectangle,rounded corners,fit=(ee) (ff)] {};
\end{tikzpicture}
\end{block}
\end{frame}

\end{document}

that allows to get those two frames:

enter image description here

Thus you can select the zone you want to highlight thanks to \tikzmark, an entire equation or just a part displaying it as "alert".

A TikZ-free solution

\documentclass{beamer}
\usepackage{amsmath,amssymb}
\usepackage{xparse}
\usepackage{xcolor}

% Code by Gonzalo Medina
% https://tex.stackexchange.com/questions/35319/a-boxed-alternative-with-minimal-spacing/35346#35346
\newbox\FBox
\NewDocumentCommand\Highlight{O{black}O{white}mO{0.5pt}O{0pt}O{0pt}}{%
    \setlength\fboxsep{#4}\sbox\FBox{\fcolorbox{#1}{#2}{#3\rule[-#5]{0pt}{#6}}}\usebox\FBox}

\usetheme{Copenhagen}

\begin{document}

\begin{frame}{The equations}
\only<1>{
\begin{align}
      &\Highlight[blue][blue!20]{$a_i$}[3pt] + b_j = 10  \qquad\forall i\in I, j\in J \\
      &c_j + d_j +\Highlight[blue][blue!20]{$a_i$}[3pt] >= 30  \qquad \forall i\in I, j\in J
\end{align}
}
\only<2>{
\begin{align}
      &a_i + b_j = 10  \qquad \forall i\in I, j\in J \\
      &\Highlight[orange][orange!20]{$c_j + d_j +a_i >= 30  \qquad\forall i\in I, j\in J$}[3pt]
\end{align}
}
\end{frame}


\end{document}

enter image description here

Beware that with the latter method, one can not place tabs (with &) inside the \Highlight command.

Solution with the hf-tikz package

\documentclass{beamer}
\usepackage{lmodern,amsmath,amssymb}
\usepackage[beamer]{hf-tikz}

\usetheme{Copenhagen}

\begin{document}

\section{Mysection}
\subsection{A subsection}
\begin{frame}{The equations}
\begin{block}{}
 \begin{align}
   \tikzmarkin<1>{a}a_i\tikzmarkend{a} + b_j = 10 & \forall i\in I, j\in J \\
   \tikzmarkin<2>{c}c_j + d_j + \tikzmarkin<1>{b}a_i\tikzmarkend{b} >= 30 & \forall i\in I, j\in J\tikzmarkend{c}
 \end{align}
\end{block}
\end{frame}

\end{document}

Notice that it also avoids the so called "jumping effect" visible in the TikZ-free solution:

enter image description here

[Tex/LaTex] Piecewise highlighting and dim the previous section/text in beamer

You can use \setbeamercovered together with overlay specifications; a little example (for further details, please refer to Section 17.6 Transparency Effects of the beamer manual):

\documentclass{beamer}

\setbeamercovered{transparent=25}

\begin{document}

\begin{frame}
\begin{itemize}
\item<1> First itemized item.
\item<2> Second itemized item.
\item<3> Third itemized item.
\end{itemize}
\end{frame}

\setbeamercovered{still covered={\opaqueness<1->{0}},again covered={\opaqueness<1->{10}}}
\begin{frame}
\onslide<1>{Some initial idea.}

\onslide<2>{An interesting development.}

\onslide<3>{An unusual conclusion.}
\end{frame}

\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] Beamer: highlighting aligned math with overlay

[Tex/LaTex] Piecewise highlighting and dim the previous section/text in beamer

Related Question