%    Copyright (C) 1992, 1994 Aladdin Enterprises.  All rights reserved.
%
% This file is part of Ghostscript.
%
% Ghostscript is distributed in the hope that it will be useful, but
% WITHOUT ANY WARRANTY.  No author or distributor accepts responsibility
% to anyone for the consequences of using it or for whether it serves any
% particular purpose or works at all, unless he says so in writing.  Refer
% to the Ghostscript General Public License for full details.
%
% Everyone is granted permission to copy, modify and redistribute
% Ghostscript, but only under the conditions described in the Ghostscript
% General Public License.  A copy of this license is supposed to have been
% given to you along with Ghostscript so you can know your rights and
% responsibilities.  It should be in a file named COPYING.  Among other
% things, the copyright notice and this notice must be preserved on all
% copies.

% viewpbm.ps
% Display a PBM/PGM/PPM file.  Currently only handles "raw" formats (P4-P6).
% Requires the Level 2 `image' operator (to handle variable pixel widths).

/s 100 string def
/readmaxv
 { f s readline pop cvx exec /maxv exch def
 } bind def
/readrow
 { 0 1 row length 1 sub { row exch f token pop put } for
 } bind def
/read01			% <count> read01 <byte>
 { 0 exch { f read pop 48 xor dup 1 le { exch dup add add } { pop } ifelse } repeat
 } bind def
/pdict 6 dict def
pdict begin
  /P1 [ { /maxv 1 def /rsize w 7 add 8 idiv def
	  /wrem w 8 mod def
          /ncomp 1 def /invert true def
	}
	{ 0 1 w 8 idiv { row exch 8 read01 put } for
	  wrem 0 ne
	   { row rsize 1 sub wrem read01 8 wrem sub bitshift put
	   } if
	  row
	}
      ] def
  /P2 [ { readmaxv /rsize w def
	  /ncomp 1 def /invert false def
	}
	{ readrow row }
      ] def
  /P3 [ { readmaxv /rsize w 3 mul def
          /ncomp 3 def /invert false def /DeviceRGB setcolorspace
	}
	{ readrow row }
      ] def
  /P4 [ { /maxv 1 def /rsize w 7 add 8 idiv def
	  /ncomp 1 def /invert true def
	}
	{ f row readstring pop }
      ] def
  /P5 [ { readmaxv /rsize w def
	  /ncomp 1 def /invert false def
	}
	{ f row readstring pop }
      ] def
  /P6 [ { readmaxv /rsize w 3 mul def
	  /ncomp 3 def /invert false def /DeviceRGB setcolorspace
	}
	{ f row readstring pop }
      ] def
end
/viewpbm		% filename ->
 { (r) file /f exch def
   f s readline pop cvn /pn exch def		% Pn
   f s readline pop		% check for comment
   (#) anchorsearch
    { pop pop f s readline pop }
   if
   cvx exec /h exch def /w exch def
   erasepage
   /DeviceGray setcolorspace
   pdict pn get dup /rprocs exch def
     0 get exec			% sets maxv, rsize, ncomp, invert
   /row rsize string def
   % Scale the image (uniformly) to fit the page.
   clippath pathbbox
     dtransform exch abs exch abs min dup scale pop pop
   20 dict begin		% image dictionary
     /ImageType 1 def
     /Width w def
     /Height h def
     /ImageMatrix [w 0 0 h neg 0 h] def
     /BitsPerComponent maxv 1 add ln 2 ln div 0.0001 sub ceiling cvi def
     /Decode [ 0 255 maxv div invert { exch } if ncomp 1 sub { 2 copy } repeat ] def
     /DataSource rprocs 1 get def
   currentdict end
   image
   showpage
 } def

% If the program was invoked from the command line, run it now.
[ shellarguments
 { counttomark 1 eq
    { viewpbm
    }
    { cleartomark
      (Usage: gs -- viewpbm.ps filename.p*m\n) print
      ( e.g.: gs -- viewpbm.ps my.ppm\n) print flush
      mark
    }
   ifelse
 }
if pop