% Run this file with pdftex, it produces a file named
% booklet.pdf in the current directory. Alfred Klomp, 2006.
% Support for non-multiples of four pages by Jakob Lund, 2011.
% Version 1.1

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

\newcount\numpages
\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

\fcount=1
\bcount=\numpages
\advance\bcount by 3     % round up to multiple of 4
\divide\bcount by 4
\multiply\bcount by 4
\leftright=0
\pdfhorigin=0bp
\pdfvorigin=0bp
\advance\numpages by 1

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

\end