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%    Copyright (C) 1992, 1996 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: impath.ps,v 1.5 2002/02/21 21:49:28 giles Exp $

% impath.ps

% Reverse-rasterize a bitmap to produce a Type 1 outline.

% (This was formerly a Ghostscript operator implemented in C.)

%	<image> <width> <height> <wx> <wy> <ox> <oy> <string>

%	  type1imagepath <substring>

%		Converts an image (bitmap) description of a character into

%		  a scalable description in Adobe Type 1 format.  The

%		  current transformation matrix should be the same as the

%		  FontMatrix of the font in which this character will be

%		  used: this establishes the scaling relationship between

%		  image pixels (the image is assumed to be 1 unit high in

%		  user space) and the character coordinate system used in

%		  the scalable description.  wx and wy are the character

%		  width, and ox and oy are the character origin relative

%		  to the lower left corner of the bitmap, in *pixels*.

%		The image is assumed to be stored in left-to-right,

%		  top-to-bottom order.  Note that this is not consistent

%		  with the `image' operator's interpretation of the CTM.

%		All coordinates in the scalable description are rounded to

%		  integers, so the coefficients in the FontMatrix should

%		  be on the order of 1/N for some value of N that is

%		  either a multiple of the height/width or is large

%		  compared to the width and height.  (There is a

%		  convention, which some PostScript programs rely on, that

%		  N=1000.)

%		Note that the encoded description has *not* been subjected

%		  to CharString encryption, which is necessary before the

%		  description can be given to type1addpath: to do this,

%		  follow the type1imagepath with

%			4330 exch dup .type1encrypt exch pop

%		If the description is too complex to fit into the supplied

%		  string, a limitcheck error results.  A good rule of

%		  thumb is that the size of the string should be about 6

%		  times the number of 1-bits in the image that are not

%		  completely surrounded by other 1-bits.

% Import the Type 1 opcodes.

(type1ops.ps) runlibfile

100 dict

dup /type1imagepath_dict exch def

begin

/rc { round cvi } bind def

/moving [/rmoveto /hmoveto /vmoveto] def

/drawing [/rlineto /hlineto /vlineto] def

% Convert the current path to a Type 1 token array.

/putxy			% x y ops -> cs_elements

 { 3 -1 roll dup x sub rc exch /x exch def

   3 -1 roll dup y sub rc exch /y exch def

   % stack: ops dx dy

   dup 0 eq

    { % dy = 0, use hmoveto/lineto

      pop exch 1 get

    }

    { 1 index 0 eq

       { % dx = 0, use vmoveto/lineto

         exch pop exch 2 get

       }

       { % use rmoveto/rlineto

         3 -1 roll 0 get

       }

      ifelse

    }

   ifelse

 } bind def

/pathtotype1		% -> charstack

 { 3 dict begin /x 0 def /y 0 def

   mark

   { moving putxy

   }

   { drawing putxy

   }

   { % Convert curve to relative form

     x y 3

      { exch neg 7 index add rc

	exch neg 6 index add rc

	8 -2 roll

      }

     repeat /y exch def /x exch def

     1 index 0 eq 5 index 0 eq and	% dy1=dx3=0, hv

      { 5 -1 roll pop exch pop /hvcurveto

      }

      { dup 0 eq 6 index 0 eq and	% dx1=dy3=0, vh

         { 6 -1 roll pop pop /vhcurveto

	 }

	 { /rrcurveto			% none of the above

	 }

	ifelse

      }

     ifelse

   }

   { /closepath

   }

   pathforall end

 } bind def

end	% type1imagepath_dict

% The main program

/type1imagepath		% image width height wx wy ox oy string ->

			% substring

 { type1imagepath_dict begin

   /tsave save def

   /ostring exch def

   /oy exch def   /ox exch def

   /wy exch def   /wx exch def

   /height exch def   /width exch def

   /data exch def

   /ofilter ostring /NullEncode filter def

   /raster width 7 add 8 idiv def

% Construct the coordinate transformation.

   height dup scale

     matrix currentmatrix matrix invertmatrix setmatrix

% Determine the left side bearing.

   /lsbx width

    { dup dup 8 idiv 0 exch

      raster raster height mul 1 sub

       { data exch get or }

      for exch 8 mod bitshift 128 and 0 ne

       { exch pop exit }

      if pop

    }

   for def

% Compute and encode the origin, width, and side bearing.

   mark

   ox oy dtransform

     rc /opty exch def   rc /optx exch def

   wx wy dtransform

     rc /iwy exch def	rc /iwx exch def

   lsbx ox sub 0 dtransform

     rc /ilsby exch def   rc /ilsbx exch def

   ilsbx

   iwy 0 ne ilsby 0 ne or

    { ilsby iwx iwy /sbw }

    { iwx /hsbw }

   ifelse

   ofilter charstack_write

% Flip over the Y axis, because the image is stored top-to-bottom.

   [1 0 0 -1 0 height] concat

% Account for the character origin.

   lsbx oy translate

% Trace the outline.

   newpath

   width height data .imagepath

   gsave matrix setmatrix pathtotype1 grestore

   ofilter charstack_write

% Terminate the output

   mark /endchar ofilter charstack_write

   ofilter .fileposition ofilter closefile	% flush buffers

   ostring 0 3 -1 roll getinterval

   tsave restore

   end

 } bind def