%!PS
%
%      This PostScript routine forms the GEM alignment barcode
%       Reduce the printed output by a factor of 7 to form the final mask
%       --  Joe Paradiso, 27-Aug-93 --
%
%
% First define the arrays
%
[ [] [0] [1] [0 0] [1 0] [0 1] [1 1] 
  [0 0 0] [1 0 0] [0 1 0] [1 1 0] [0 0 1] [1 0 1] [0 1 1] [1 1 1] ]
/bars exch def      % The basic bar codes are defined in this array
%
[0 12 1 10 2 13 3 14 4 9 5 7 6 11 8 0 0]
/sqnce exch def     % The sequence of bar codes are defined here
%
/ntrail 8 def    % No. of thin bars before and after main code
/scfac 2.84375 def      % The scale factor
/maxl 72 6.43 mul scfac div def   % Maximum line length 
/endl  10 def   % End-clip length 
/ofstx 80 scfac div def   % Initial offsets
/ofsty 80 scfac div def
%
/prtprc      % Procedure to print out barcode
{/ninx exch def
 0.75 0 rmoveto
 2.5 setlinewidth
 0 maxl rlineto   % Draw thick guidebar
 dodraw
 0.75 maxl neg rmoveto
 2 0 rmoveto
 1 setlinewidth
 bars ninx get  % get the current barcode description
 /cdex exch def
  cdex {prtbars} forall   % Print out the relevant bars
  dodraw } def
%
/prtbars    % Procedure to print out barcode bars
{0 ne 
  {0 maxl rlineto     % Draw the line if the  code is nonzero
  0 maxl neg rmoveto } if
 2 0 rmoveto   % Insert space
 } def
%
/headtrl   % Procedure to print out header/trailer bars
{0 maxl rlineto
  2 maxl neg rmoveto} def
%
/dodraw   % Procedure to print the current path and preserve coordinates
{ currentpoint
 stroke
 moveto } def
%
% Draw a Barcode with header and trailer
%
/bardraw
 {1 setlinewidth   % select thin line
 ntrail {headtrl} repeat    % Draw the header bars
 dodraw
 sqnce {prtprc} forall     % Draw the main barcode
 ntrail {headtrl} repeat    % Draw the trailer bars
 dodraw } def
%
%    Routine to draw a crosshair at the current origin
%
/crosshair
{gsave        % save graphics state
.2625 .2625  scale       % Scale coordinates so crosshair is appropriately small
10 0 moveto 
0 0 10 0 360 arc 
1 setgray 
fill
0 setgray 
8 0 moveto 
0 0 8 0 360 arc
-10 0 moveto 
10 0 lineto 
0 -10 moveto 
0 10 lineto 
stroke
4 0 moveto 
0 0 4 0 360 arc 
fill
-4 0 moveto 
4 0 lineto 
0 -4 moveto 
0 4 lineto 
1 setgray 
stroke 
grestore        % Restore graphics state
 }  def
%
%    Program Execution
%
scfac scfac scale   % Scale x and y coordinates appropriately
gsave
ofstx ofsty moveto  % Initialize coordinates
0.0 setgray   % Color the vertical bars black
bardraw    % Print the vertical barcode
currentpoint
pop
ofstx sub
/xww exch def    % Get x maximum
90 rotate    % Flip the x and y coordinates
1 1 neg scale   % Flip the y coordinate to compensate the rotation
ofstx 1.5 add ofsty 0.5 sub moveto  % Initialize coordinates
1.0 setgray   % Color the horizontal bars white
bardraw    % Print the horizontal barcode
-0.5 0 rmoveto   % Correct final positioning       
0 maxl rlineto    % Clip excess lines with white rectangle
endl 0 rlineto
0 maxl neg rlineto
endl neg 0 rlineto
fill
%
grestore
ofstx ofsty translate  % Initialize coordinates for crosshair drawing
-10 -9.5 translate
crosshair  % Lower Left
xww 18 add
0 translate
crosshair % Lower Right
xww 16.5 add 
4 add    % Compensate for wider y-width
0 exch translate
crosshair  % Upper Right
xww 18 add
neg 0 translate
crosshair  % Upper Left