UPC码(Universal Product Code)是最早大规模应用的条码，其特性是一种长度固定、连续性的条码，由於其应用范围广泛，故又被称万用条码。UPC码仅可用来表示数字，故其字码集为数字0~9。UPC码共有A、B、C、D、E等五种版本。本文介绍的就是用 PHP 生成 UPC- A 条形码。

代码:

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

{

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('13322483157');

?>

效果