Source

beamer / base / beamerbasetwoscreens.sty

% Copyright 2003--2007 by Till Tantau
% Copyright 2010 by Vedran Mileti\'c
%
% This file may be distributed and/or modified
%
% 1. under the LaTeX Project Public License and/or
% 2. under the GNU Public License.
%
% See the file doc/licenses/LICENSE for more details.
%
% version 1.71 bugfix for \pgfpagescurrentpagewillbelogicalpage (hv)
%
%
\ProvidesPackageRCS $Header$

\mode
<presentation>

\newif\ifbeamer@twoscreenstext
\newif\ifbeamer@dosecondmode

\defbeameroption{previous slide on second screen}[right]%
{
  \pgfpagesuselayout{two screens with lagging second}[second #1]
  \beamer@twoscreenstexttrue
  \nofiles
}

\defbeameroption{second mode text on second screen}[right]%
{
  \pgfpagesuselayout{two screens with optional second}[second #1]
  \beamer@twoscreenstexttrue
}

\defbeameroption{always typeset second mode}[true]%
{
  \def\beamer@defaultdosecondmode{#1}
}
\def\beamer@defaultdosecondmode{false}


\long\def\beamer@dosecondscreennow#1{% called from \beamer@doseveralframes
  \ifbeamer@dosecondmode%
    {%
      \clearpage%
      \def\beamer@currentmode{second}
      \def\beamer@doifnotinframe{}%
      \def\beamer@doifinframe{\begin{beamer@frameslide}%
          #1%
        \end{beamer@frameslide}%
        \pgfpagescurrentpagewillbelogicalpage{2}%
        \clearpage%
      }%
      {\beamer@masterdecode{\beamer@whichframes}}%
      \beamer@donow%
    }%
  \fi%
}


\mode
<all>