PHP生成条形码

<?php

function upcabarcode($code) {
  $lw = 2; $hi = 100;
  $lencode = array('0001101','0011001','0010011','0111101','0100011',
                   '0110001','0101111','0111011','0110111','0001011');
  $rencode = array('1110010','1100110','1101100','1000010','1011100',
                   '1001110','1010000','1000100','1001000','1110100');
  $ends = '101'; $center = '01010';
  /* upc-a must be 11 digits, we compute the checksum. */
  if ( strlen($code) != 11 ) { die("upc-a must be 11 digits."); }
  /* compute the ean-13 checksum digit */
  $ncode = '0'.$code;
  $even = 0; $odd = 0;
  for ($x=0;$x<12;$x++) {
    if ($x % 2) { $odd += $ncode[$x]; } else { $even += $ncode[$x]; }
  }
  $code.=(10 - (($odd * 3 + $even) % 10)) % 10;
  /* create the bar encoding using a binary string */
  $bars=$ends;
  $bars.=$lencode[$code[0]];
  for($x=1;$x<6;$x++) {
    $bars.=$lencode[$code[$x]];
  }
  $bars.=$center;
  for($x=6;$x<12;$x++) {
    $bars.=$rencode[$code[$x]];
  }
  $bars.=$ends;
  /* generate the barcode image */
  $img = imagecreate($lw*95+30,$hi+30);
  $fg = imagecolorallocate($img, 0, 0, 0);
  $bg = imagecolorallocate($img, 255, 255, 255);
  imagefilledrectangle($img, 0, 0, $lw*95+30, $hi+30, $bg);
  $shift=10;
  for ($x=0;$x<strlen($bars);$x++) {
    if (($x<10) || ($x>=45 && $x<50) || ($x >=85)) { $sh=10; } else { $sh=0; }
    if ($bars[$x] == '1') { $color = $fg; } else { $color = $bg; }
    imagefilledrectangle($img, ($x*$lw)+15,5,($x+1)*$lw+14,$hi+5+$sh,$color);
  }
  /* add the human readable label */
  imagestring($img,4,5,$hi-5,$code[0],$fg);
  for ($x=0;$x<5;$x++) {
    imagestring($img,5,$lw*(13+$x*6)+15,$hi+5,$code[$x+1],$fg);
    imagestring($img,5,$lw*(53+$x*6)+15,$hi+5,$code[$x+6],$fg);
  }
  imagestring($img,4,$lw*95+17,$hi-5,$code[11],$fg);
  /* output the header and content. */
  header("content-type: image/png");
  imagepng($img);
}

upcabarcode('47101496236');

?>