% Run this file with pdftex, it produces a file named
% booklet.pdf in the current directory. Alfred Klomp, 2006.

\def\bookletfile{/home/alfred/mydocument.pdf}

\newcount\numpages
\newcount\halfnumpages
\newcount\fcount         % forwards count, starts at page 1 and counts up
\newcount\bcount         % backwards count, starts at last page and counts down
\newcount\leftright      % is the page with the lowest number on the left?
\newcount\pagea          % pageno. to be placed on the left
\newcount\pageb          % pageno. to be placed on the right

\pdfpagewidth  297mm     % landscape A4 format
\pdfpageheight 210mm
  
\pdfximage {\bookletfile}
\numpages=\pdflastximagepages
\halfnumpages=\numpages
\divide\halfnumpages by 2
\fcount=1
\bcount=\numpages
\leftright=0
\pdfhorigin=0bp
\pdfvorigin=0bp

\loop
  \ifnum\leftright=0
    \pagea=\bcount
    \pageb=\fcount
    \leftright=1
  \else
    \pagea=\fcount
    \pageb=\bcount
    \leftright=0
  \fi
  \shipout\hbox to \pdfpagewidth {%
    \pdfximage height \pdfpageheight page \pagea {\bookletfile}%
    \pdfrefximage\pdflastximage%
    \hfil%
    \pdfximage height \pdfpageheight page \pageb {\bookletfile}%
    \pdfrefximage\pdflastximage%
  }
  \advance\fcount by 1
  \advance\bcount by -1
  \ifnum\bcount>\halfnumpages\repeat

\end