Some time ago I wrote this for someone who wanted to slice up 2x2 PowerPoint style slides. I have no idea if it still works but you can try it. Note this only works with Ghostscript.
%!PS
% Copyright (C) 2011 Artifex Software, Inc. All rights reserved.
%
% This software is provided AS-IS with no warranty, either express or
% implied.
%
% This software is distributed under license and may not be copied,
% modified or distributed except as expressly authorized under the terms
% of the license contained in the file LICENSE in this distribution.
%
% For more information about licensing, please refer to
% http://www.ghostscript.com/licensing/. For information on
% commercial licensing, go to http://www.artifex.com/licensing/ or
% contact Artifex Software, Inc., 101 Lucas Valley Road #110,
% San Rafael, CA 94903, U.S.A., +1(415)492-9861.
%
% Slice up a PDF file
%
% usage: gs -sFile=____.pdf -dSubPagesX= -dSubPagesY= [-dSubPageOrder=] [-dVerbose=]pdf_slice.ps
%
% SubPageOrder is a bit field;
% Default = 0
% Bit 0 - 0 = top to bottom
% 1 = bottom to top
% Bit 1 - 0 = left to right
% 1 = right to left
% Bit 3 - 0 = increase x then y
% - 1 = increase y then x
%
% 0 - page 1 at top left, increasing left to right, top to bottom
% 1 - page 1 at bottom left increasing left to right, bottom to top
% 2 - page 1 at top right, increasing right to left, top to bottom
% 3 - page 1 at bottom right increasing right to left, bottom to top
% 4 - page 1 at top left, increasing top to bottom, left to right
% 5 - page 1 at bottom left increasing bottom to top, left to right
% 6 - page 1 at top right, increasing top to bottom, right to left
% 7 - page 1 at bottom right increasing bottom to top, right to left
%
% Check the parameters to see they are present and of the correct type
%
/Usage {
( usage: gs -dNODISPLAY -q -sFile=____.pdf \n) =
( -dSubPagesX= -dSubPagesY= [-dSubPageOrder=] pdf_slice.ps \n) =
(Please see comments in pdf_slice.ps for more details) =
flush
quit
} bind def
/Verbose where not {
/Verbose false def
}{
pop /Verbose true def
} ifelse
/File where not {
(\n *** Missing source file. \(use -sFile=____.pdf\)\n) =
Usage
} {
pop
}ifelse
/SubPagesX where not {
(\n *** SubPagesX not integer! \(use -dSubPagesX=\)\n) =
Usage
} {
Verbose { (SubPagesX ) print } if
SubPagesX type
Verbose { dup == } if
/integertype eq not {
(\n *** SubPagesX not integer! \(use -dSubPagesX=\)\n) =
Usage
}
pop
}ifelse
/SubPagesY where not {
(\n *** SubPagesY not integer! \(use -dSubPagesY=\)\n) =
Usage
} {
Verbose { (SubPagesY ) print } if
SubPagesY type
Verbose { dup == } if
/integertype eq not {
(\n *** SubPagesY not integer! \(use -dSubPagesY=\)\n) =
Usage
}
pop
}ifelse
/SubPageOrder where not {
/SubPageOrder 0 def
} {
Verbose { (SubPageOrder ) print } if
SubPageOrder type
Verbose { dup == } if
dup ==
/integertype eq not {
(\n *** SubPageOrder not integer! \(use -dSubPageOrder=\)\n) =
Usage
}
pop
}ifelse
%
% Turns off most messages
%
/QUIET true def % in case they forgot
%() =
%
% Open the PDF file and tell the PDF interpreter to start dealing with it
%
File dup (r) file runpdfbegin pop
/PDFPageCount pdfpagecount def
%
% Set up our bookkeeping
%
% First get the size of the page from page 1 of the PDF file
% We assume that all PDF pages are the same size.
%
1 pdfgetpage currentpagedevice
1 index get_any_box
exch pop dup 2 get exch 3 get
/PDFHeight exch def
/PDFWidth exch def
%
% Now get the page size of the current device. We are assuming that
% this is the size of the individual sub-pages in the original PDF. NB
% This assumes no margins between sub-pages, all sub-pages the same size.
%
currentpagedevice /PageSize get
dup 0 get /SubPageWidth exch def
1 get /SubPageHeight exch def
%
% Calculate the margins. This is the margin between the page border and
% the enclosed group of sub-pages, we assume there are no borders
% between sub pages.
%
/TopMargin PDFHeight SubPageHeight SubPagesY mul sub 2 div def
/LeftMargin PDFWidth SubPageWidth SubPagesX mul sub 2 div def
Verbose {
(PDFHeight = ) print PDFHeight ==
(PDFWidth = ) print PDFWidth ==
(SubPageHeight = ) print SubPageHeight ==
(SubPageWidth = ) print SubPageWidth ==
(TopMargin = ) print TopMargin ==
(LeftMmargin = ) print LeftMargin ==
} if
%
% This rouitne calculates and sets the PageOffset in the page device
% dictionary for each subpage, so that the PDF page is 'moved' in such
% a way that the required sub page is under the 'window' which is the current
% page being imaged.
%
/NextPage {
SubPageOrder 2 mod 0 eq {
/H SubPagesY SubPageY sub SubPageHeight mul TopMargin add def
}{
/H SubPageY 1 sub SubPageHeight mul TopMargin add def
} ifelse
SubPageOrder 2 div floor cvi 2 mod 0 eq {
/W SubPageX 1 sub SubPageWidth mul LeftMargin add def
}{
/W SubPagesX SubPageX sub SubPageWidth mul LeftMargin add def
} ifelse
<< /PageOffset [W neg H neg]>> setpagedevice
Verbose {
(SubPageX ) print SubPageX ==
(SubPageY ) print SubPageY ==
(X Offset ) print W ==
(Y Offset ) print H == flush
} if
PDFPage
} bind def
%
% The main loop
% For every page in the original PDF file
%
1 1 PDFPageCount
{
/PDFPage exch def
% Do the gross ordering here rather than in
% NextPage. We eiither process rows and then
% columns, or columns then rows, depending on
% Bit 3 of SubPageorder
SubPageOrder 3 le {
1 1 SubPagesY {
/SubPageY exch def
1 1 SubPagesX {
/SubPageX exch def
NextPage
pdfgetpage
pdfshowpage
} for
} for
} {
1 1 SubPagesX {
/SubPageX exch def
1 1 SubPagesY {
/SubPageY exch def
NextPage
pdfgetpage
pdfshowpage
} for
} for
} ifelse
} for