{ sqrt } settransfer

%!
% grayscaled text test, including a trivial user bitmap font

/inch {72 mul} def

/BuildCharDict 10 dict def
/$ExampleFont 7 dict def
$ExampleFont begin
  /FontType 3 def % user defined font.
  /FontMatrix [1 0 0 1 0 0] def
  /FontBBox [0 0 1 1] def
  /Encoding 256 array def
  0 1 255 {Encoding exch /.notdef put} for
  Encoding (a) 0 get /plus put
  /CharStrings 2 dict def
  CharStrings /.notdef {} put
  CharStrings /plus
    { gsave
      0 0 moveto
      32 32 true [32 0 0 -32 0 32]
    {<0007E000 0007E000 0007E000 0007E000 0007E000 0007E000 0007E000 0007E000
      0007E000 0007E000 0007E000 0007E000 0007E000 FFFFFFFF FFFFFFFF FFFFFFFF
      FFFFFFFF FFFFFFFF FFFFFFFF 0007E000 0007E000 0007E000 0007E000 0007E000
      0007E000 0007E000 0007E000 0007E000 0007E000 0007E000 0007E000 0007E000>
      } imagemask
      grestore
    } put
  /BuildChar
    { BuildCharDict begin
        /char exch def
        /fontdict exch def
        /charproc
          fontdict /Encoding get char get
          fontdict /CharStrings get
          exch get def
        1 0 0 0 1 1 setcachedevice 
        charproc
      end
    } def
end

/MyFont $ExampleFont definefont pop

/drawbitfont
  { gsave
      newpath
        4.5 inch 1 inch moveto
        3.5 inch 0 rlineto
        0 6 inch rlineto
        -3.5 inch 0 rlineto
      closepath
        .5 inch 7.5 inch moveto
        7.5 inch 0 rlineto
        0 1.5 inch rlineto
        -7.5 inch 0 rlineto
      closepath
      0 setgray
      fill

      /MyFont findfont 72 scalefont setfont
      .75 inch 7.75 inch moveto
      0 1 6
        { /n exch def
          1 n 6 div sub setgray
          (a) show
        } for

      /MyFont findfont 12 scalefont setfont
      4.5 inch 1 inch translate
      0 1 10
        { /n exch def
          .25 inch n 2 div 0.5 add inch moveto
          1 n 10 div sub setgray
          (aaaaaaaaaaaaaaaaa) show
        } for
    grestore
  } def

/graychars
  { gsave
    /Times-Roman findfont 12 scalefont setfont
    .5 inch 1 inch translate
    0 1 10
      { /n exch def
        .25 inch n 2 div 0.5 add inch moveto
        1 n 10 div sub setgray
        (ABCDEFGHIJKLMNOPQRSTUVWXYZ) show
      } for
    grestore
  } def

/11graychars	% takes <llx> <lly>
  { gsave
      /Times-Roman findfont 72 scalefont setfont
      translate
      0 0 moveto
      0 1 10
        { /n exch def
          1 n 10 div sub setgray
          ( ) dup 0 n 65 add put show
        } for
    grestore
  } def

/graystrip	% takes <llx> <lly>, prints 1 inch thick gray strip
  { gsave
      translate
      newpath
        0 0 moveto
        7.5 inch 0 rlineto
        0 1 inch rlineto
        -7.5 inch 0 rlineto
      closepath
      0.5 setgray
      fill
    grestore
  } def

/charsongray
   { gsave
       newpath
         0.5 inch 1 inch moveto
         3.5 inch 0 rlineto
         0 6 inch rlineto
         -3.5 inch 0 rlineto
         0 -6 inch rlineto
       0.5 setgray
       closepath fill
       newpath
       graychars
     grestore
   } def

 0.5 inch 9.5 inch graystrip
 0.8 inch 9.67 inch 11graychars
 charsongray
drawbitfont
showpage