Semi-transparent figures in beamer (pdflatex)

Question

I am attempting to use overlays with figures to save myself from creating a different image for each slide. The overlay works with any text I include, but not with the figures. For example:

\setbeamercovered{dynamic}
\begin{figure}\resizebox{10.0cm}{!}{
        \includegraphics{problem-a.pdf}
        Test A
        \pause
        \includegraphics{problem-b.pdf}
        Test B
        \pause
        \includegraphics{problem-c.pdf}
        Test C
}\end{figure}

Results in the text "Test B" and "Test C" being shaded on the first slide, but the figures corresponding to "problem-b" and "problem-c" are not shaded.

Mariselamarish

The graphics you're including are pdfs, you could just edit them externally (using inkscape, adobe's thing?, etc.), or convert them to bitmaps (using ghostscript, incscape etc.) and then edit and include those (using paint, paint.net, gimp, etc.) – Poling

Answer 1

For anyone that stumbles upon this, the best thing I've found so far is to use tikz and setup a custom transparency mode:

\gdef\transparent@value{100}
\newcommand{\getbeamertrans}{
    \transparent@value/100
}
\newcommand{\set@transparent}[1]{\gdef\transparent@value{#1}}
\def\opaquenessCustom#1{%
\only<1->{%
  \beamer@actions{%
    \set@transparent{#1}%
    \expandafter\xdef\csname beamer@oldcolorhook%
    \the\beamer@coveringdepth\endcsname{\beamer@colorhook}%
    \expandafter\xdef\csname beamer@oldpgfextension%
    \the\beamer@coveringdepth\endcsname{\beamer@pgfextension}%
    {\globalcolorstrue\colorlet{beamer@freeze\the\beamer@coveringdepth}{bg}}%
    \xdef\beamer@colorhook{!#1!beamer@freeze%
      \the\beamer@coveringdepth\beamer@colorhook}%
    \gdef\beamer@pgfextension{!#1opaque}%
    \color{.}%
  }%
  {%
    \set@transparent{100}%
    \xdef\beamer@colorhook{\csname beamer@oldcolorhook%
      \the\beamer@coveringdepth\endcsname}%
    \xdef\beamer@pgfextension{\csname beamer@oldpgfextension%
      \the\beamer@coveringdepth\endcsname}%
    \color{.}%
  }}%
}%
\define@key{beamer@mixin}{transparent}[15]{%
    \def\beamer@uncoverbeforeactions{\ignorespaces\opaquenessCustom{#1}}%
    \def\beamer@uncoverafteractions{\ignorespaces\opaquenessCustom{#1}}%
}
\newcommand{\BeamerGraphic}[1]{%
    \begin{tikzpicture}%
        {\node[opacity=\getbeamertrans] {\includegraphics{#1}};}%
    \end{tikzpicture}%
}

Mariselamarish

I realize this is an old question, but I can't get this to work... what packages did you include? – Leucite

@greschd: According to my records: subfigure, tikz, textcomp – Mariselamarish

Answer 2

Another approach could be to temporarily cover the image with a semi-transparent shape:

\documentclass{beamer}
\usepackage{tikz}
\setbeamercovered{dynamic}

\begin{document}

\begin{frame}

\begin{figure}
    \includegraphics[width=2cm,page=1]{example-image-duck}
    Test A
    \pause
    \begin{tikzpicture}
    \node[anchor=south west,inner sep=0] (B) at (4,0) {\includegraphics[width=2cm,page=2]{example-image-duck}};
    \only<1>{%
        \fill [draw=none, fill=white, fill opacity=0.7] (B.north west) -- (B.north east) -- (B.south east) -- (B.south west) -- (B.north west) -- cycle;
    }
    \end{tikzpicture}
    Test B
    \pause  
     \begin{tikzpicture}
        \node[anchor=south west,inner sep=0] (B) at (4,0) {\includegraphics[width=2cm,page=3]{example-image-duck}};
        \only<1-2>{%
            \fill [draw=none, fill=white, fill opacity=0.7] (B.north west) -- (B.north east) -- (B.south east) -- (B.south west) -- (B.north west) -- cycle;
        }
     \end{tikzpicture}  
    Test C
\end{figure}
\end{frame}

\end{document}

Glidden

this only works properly with a solid background, adjusting the opacity works even if you have a gradient (or other custom) background – Mariselamarish

Answer 3

I've done something similar doing the following:

\begin{figure}
                \includegraphics<1->{problem-a.pdf}
                \onslide<1->{Test A}                    
                \includegraphics<2->{problem-b.pdf}
                \onslide<1->{Test B}
                \includegraphics<3->{problem-c.pdf}
                \onslide<1->{Test C}
\end{figure}

Maybe its useful to you

Kyat

Answer 4

You can find more information about using imported graphics in pdflatex in this document. Look for Chapter 12: "Overlaying Two Imported Graphics".

Cavy