用PHP实现登陆验证码(类似条行码状)

<?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('12345678901');
?>
<P align=center><IMG src="img/2194160.JPG" border=0>