% Copyright (C) 2001-2021 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.
%
% Refer to licensing information at http://www.artifex.com or contact
% Artifex Software, Inc.,  1305 Grant Avenue - Suite 200, Novato,
% CA 94945, U.S.A., +1(415)492-9861, for further information.
%

% viewpcx.ps
% Display a PCX 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.
% If FITPAGE is true it fits the output page size to the image, honouring SCALE
% ****NOTE: does not handle multi-plane images with palette.

/pcxbytes [
  0 1 255 {
    64 string exch 0 1 63 {
      3 copy exch put pop
    } for pop
  } for
] readonly def
/readpcx {			% - readpcx <str>
  f				% gets replaced
  dup read not {
    pop ()
  } {
    dup 192 lt {
      ( ) dup 0 4 -1 roll put exch pop
    } {
      192 sub //pcxbytes 3 -1 roll read pop get exch 0 exch getinterval
    } ifelse
  } ifelse
} def
/get2				% <string> <index> get2 <int>
 { 2 copy get 3 1 roll 1 add get 8 bitshift add
 } bind def
/dsproc
 { df s readstring pop		% s gets filled in
   s1 () ne { df s1 readstring pop pop } if % discard padding bytes
 } def				% don't bind, must be writable
/viewpcx			% <filename> viewpcx -
 { 100 dict begin
   /fname 1 index def
   /f exch (r) file def
                % Read and unpack the header.
   /header f 128 string readstring pop def
   /version header 1 get def
   /bpp header 3 get def
   /w header 8 get2 header 4 get2 sub 1 add def
   /h header 10 get2 header 6 get2 sub 1 add def
   /FITPAGE where
   {
     /FITPAGE get
     {
       5 dict begin
       /SCALE where
       {
         pop
         /Width w SCALE mul def
         /Height h SCALE mul def
       }
       {
         /Width w def
         /Height h def
       } ifelse
       % we've already set the image color space, so
       % push it on the stack, and set it again after
       % setting the page size
       <</PageSize [Width Height] >> setpagedevice
       end
     } if
   }
   {
     /FITPAGE false def
   } ifelse
   /nplanes header 65 get def
   /bpl header 66 get2 def
   /palinfo header 68 get2 def
   /nbits bpp nplanes mul def
   version 5 eq
    { nbits 8 le
       { /cspace
           [/Indexed   /DeviceRGB   1 bpp bitshift 1 sub
         f fileposition
         1 nbits bitshift 3 mul string
         fname status pop pop pop exch pop
         1 index length sub f exch setfileposition
         f exch readstring pop
         exch f exch setfileposition
           ] def
         /decode [0 cspace 2 get] def
       }
       { /cspace /DeviceRGB def
         /decode [0 1 0 1 0 1] def
       }
      ifelse
    }
    { /cspace
        [/Indexed   /DeviceRGB   1 bpp bitshift 1 sub
         header 16 1 nbits bitshift 16 .min 3 mul getinterval
        ] def
      /decode [0 cspace 2 get] def
    }
   ifelse
                % Set up scaling.
   /SCALE where
    {
      pop
      FITPAGE
      {
        % Map pixels SCALE-for-1.  Assume orthogonal transformation.
        w SCALE mul
        h SCALE mul
      }
      {
        % Map pixels SCALE-for-1.  Assume orthogonal transformation.
        w 1 0 dtransform add abs div SCALE mul
        h 0 1 dtransform add abs div SCALE mul
      } ifelse
    }
    {
      FITPAGE
      {
        w h
      }
      {
        % Scale the image (uniformly) to fit the page.
        clippath pathbbox pop pop translate
        pathbbox .min exch pop exch pop ceiling
        dup h w gt { w mul h div exch } { h mul w div } ifelse
      } ifelse
    }
   ifelse scale
                % Since the number of bytes per line is always even,
                % it may not match the width specification.
   /wbpl w bpp mul 7 add 8 idiv def
                % Define the data source procedure.
   /s1 bpl wbpl sub string def
   /df /readpcx load copyarray dup 0 f put cvx bind readonly
     0 () /SubFileDecode filter def
   /dsource [ nplanes
    { /dsproc load copyarray
      dup 1 wbpl string put
      cvx bind readonly
    }
   repeat ] def
                % Construct the image dictionary.
   20 dict begin		% image dictionary
     /ImageType 1 def
     /Width w def
     /Height h def
     /ImageMatrix [w 0 0 h neg 0 h] def
     /BitsPerComponent bpp def
     /Decode decode def
     /DataSource dsource dup length 1 gt
      { /MultipleDataSources true def }
      { 0 get }
     ifelse def
   currentdict end
                % Finally, display the image.
   cspace setcolorspace
   image
   showpage
   df closefile
   f closefile
   end
 } bind def

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