利用php生成二维码，非常实用

<?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); 
} 
?>