plan9fox/sys/lib/ghostscript/viewpbm.ps

%    Copyright (C) 1992, 1995, 1996, 1998, 1999 Aladdin Enterprises.  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.

% $Id: viewpbm.ps,v 1.5 2002/06/02 12:03:28 mpsuzuki Exp $
% viewpbm.ps
% Display a PBM/PGM/PPM file.
% Requires the Level 2 `image' operator (to handle variable pixel widths).
% If SCALE is defined, maps input pixels to output pixels with that scale;
% if SCALE is undefined, scales the image to fit the page.

/s 100 string def
/readmaxv {		% <file> readmaxv -
  10 string readline pop cvx exec /maxv exch def
} bind def
/readrow {		% <file> <row> readrow <row>
  0 1 2 index length 1 sub {
    1 index exch 3 index token pop put
  } for exch pop
} bind def
/read01 {		% <file> <count> read01 <byte>
  0 exch {
    1 index read pop 48 xor dup 1 le { exch dup add add } { pop } ifelse
  } repeat
} bind def
/readrow01 {		% <file> <row> readrow01 <row>
  0 1 w 8 idiv {
    1 index exch 3 index 8 read01 put
  } for
  wrem 0 ne {
     dup rsize 1 sub wrem read01 8 wrem sub bitshift put
  } if
  exch pop
} bind def
/readwh {		% <file> readwh <w> <h>
 dup s readline pop		% check for comment
 (#) anchorsearch {
   pop pop dup s readline pop
 } if
 cvx exec
} bind def
/pbmtypes mark
% The procedures in this dictionary are called as
%	<file> Pn <w> <h> <readproc>
/P1 {			% ASCII 1-bit white/black
  /bpc 1 def /maxv 1 def /rsize w 7 add 8 idiv def
  /wrem w 8 mod def
  /ncomp 1 def /invert true def /DeviceGray setcolorspace
  readwh
	{ readrow01 }
} bind
/P2 {			% ASCII 8-bit gray
  readwh
  /bpc 8 def 2 index readmaxv /rsize 2 index def
  /ncomp 1 def /invert false def /DeviceGray setcolorspace
	{ readrow }
} bind
/P3 {			% ASCII 8-bit RGB
  readwh
  /bpc 8 def 2 index readmaxv /rsize 2 index 3 mul def
  /ncomp 3 def /invert false def /DeviceRGB setcolorspace
	{ readrow }
} bind
/P4 {			% Binary 1-bit white/black
  readwh
  /bpc 1 def /maxv 1 def /rsize 2 index 7 add 8 idiv def
  /ncomp 1 def /invert true def /DeviceGray setcolorspace
	{ readstring pop }
} bind
/P5 {			% Binary 8-bit gray
  readwh
  /bpc 8 def 2 index readmaxv /rsize 2 index def
  /ncomp 1 def /invert false def /DeviceGray setcolorspace
	{ readstring pop }
} bind
/P6 {			% Binary 8-bit RGB
  readwh
  /bpc 8 def 2 index readmaxv /rsize 2 index 3 mul def
  /ncomp 3 def /invert false def /DeviceRGB setcolorspace
	{ readstring pop }
} bind
.dicttomark readonly def
/pbmsetup {			% <file> <w> <h> <readproc> runpbm -
   /readproc exch def
   /h exch def
   /w exch def
   /f exch def
   20 dict begin		% image dictionary
     /ImageType 1 def
     /Width w def
     /Height h def
     /ImageMatrix [w 0 0 h neg 0 h] def
     /BitsPerComponent bpc def
     /Decode [ 0 255 maxv div invert { exch } if ncomp 1 sub { 2 copy } repeat ] def
     /DataSource [ f rsize string /readproc load /exec load ] cvx def
   currentdict end
} def
/imagescale {			% <imagedict> imagescale -
  begin
    /SCALE where {
      pop
	% Map pixels SCALE-for-1.  Assume orthogonal transformation.
      Width 1 0 dtransform add abs div SCALE mul
      Height 0 1 dtransform add abs div SCALE mul
    } {
	% Scale the image (uniformly) to fit the page.
      clippath pathbbox pop pop translate
      pathbbox .min exch pop exch pop ceiling
      dup Height Width gt {
	Width mul Height div exch
      } {
	Height mul Width div
      } ifelse
    }
    ifelse scale
  end
} def

% Image a PBM file page by page.
/viewpbm {			% <filename> viewpbm -
  20 dict begin
    (r) file /pf exch def {
      pf token not { exit } if
      pbmtypes exch get pf exch exec pbmsetup
      dup imagescale image showpage
    } loop
  end
} def

% Reassemble a composite PBM file from the CMYK separations.
/viewpsm {
  20 dict begin
    /fname exch def
    /sources [ 0 1 3 {
      /plane exch def 
      /pf fname (r) file def
      pf pbmtypes pf token pop get exec
		% Stack: pf w h readproc
      plane {
	/readproc exch def /h exch def /w exch def pop
	/row rsize string def
	h { pf row readproc pop } repeat
	pf pbmtypes pf token pop get exec
      } repeat
      pbmsetup
    } for ] def
    /datas [ sources { /DataSource get 0 get } forall ] def
    /decode sources 0 get /Decode get
      dup 0 get exch 1 get add cvi 0 exch
      2 copy 4 copy 8 array astore def
    sources 0 get
      dup /MultipleDataSources true put
      dup /DataSource datas put
      dup /Decode decode put
    /DeviceCMYK setcolorspace
    dup imagescale image showpage
  end
} def

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