Using PHP to generate EAN

Standard | Bar code This sky saw someone fateh discuss such as using PHP to generate barcodes, so it took a little time to learn the EAN_13 standard. EAN_13 standard is widely used barcode coding standards, mainly used in the commodity circulation, such as we see the bar code is this code standard, as well as books on the coding standard is this coding standard.
The following is my section of code generated is EAN_13 standard barcode, need PHP+GD environment
[Code:1:dfc50fedcf]<?
function Ean_13 ($code) {
The width of a cell
$LW = 2;
Barcode High
$hi = 100;
The guide code is no coding,is used to show the left part coding type//
Array Guide is used to record the ean_13 are left part coding type//
$Guide = Array (1=> ' aaaaaa ', ' aababb ', ' aabbab ', ' abaabb ', ' Abbaab ', ' Abbbaa ', ' ababab ', ' Ababba ', ' Abbaba ');
$Lstart = ' 101 ';
$Lencode = Array ("A" => Array (' 0001101 ', ' 0011001 ', ' 0010011 ', ' 0111101 ', ' 0100011 ', ' 0110001 ', ' 0101111 ', ' 0111011 ', ') ' 0110111 ', ' 0001011 '),
"B" => Array (' 0100111 ', ' 0110011 ', ' 0011011 ', ' 0100001 ', ' 0011101 ', ' 0111001 ', ' 0000101 ', ' 0010001 ', ' 0001001 ', ') ', ' 0010111 '));
$Rencode = Array (' 1110010 ', ' 1100110 ', ' 1101100 ', ' 1000010 ', ' 1011100 ',
' 1001110 ', ' 1010000 ', ' 1000100 ', ' 1001000 ', ' 1110100 ');

$center = ' 01010 ';

$ends = ' 101 ';
if (strlen ($code)!= 13)
{die ("upc-a must be digits.");}
$lsum = 0;
$rsum = 0;
For ($i =0 $i < (strlen ($code)-1); $i + +)
{
if ($i% 2)
{
$odd + + $ncode [$x]
$lsum + + (int) $code [$i];
}else{
$rsum + + (int) $code [$i];
}

}
$tsum = $lsum *3 + $rsum;
if ($code [a]!= (10-($tsum% 10))
{
Die ("The Code is bad!");
}

echo $Guide [$code [0]];
$barcode = $Lstart;
For ($i =1 $i <=6; $i + +)
{
$barcode. = $Lencode [$Guide [$code [0]][($i-1)]] [$code [$i]];
}
$barcode. = $center;

For ($i =7 $i <13; $i + +)
{
$barcode. = $Rencode [$code [($i)]];
}
$barcode. = $ends;

$img = Imagecreate ($lw *95+60, $hi +30);
$FG = imagecolorallocate ($img, 0, 0, 0);
$BG = Imagecolorallocate ($img, 255, 255, 255);
Imagefilledrectangle ($img, 0, 0, $lw *95+60, $hi +30, $BG);
$shift = 10;
for ($x =0; $x <strlen ($barcode); $x + +) {
if (($x <4) | | ($x >=45 && $x <50) | | ($x >=92))
{
$sh = 10;
} else {
$sh = 0;
}
if ($barcode [$x] = = ' 1 ')
{
$color = $FG;
} else {
$color = $BG;
}
Imagefilledrectangle ($img, ($x * $lw) +30,5, ($x + 1) * $LW +29, $hi +5+ $sh, $color);
}
/* Add the Human readable Label * *
Imagestring ($img, 5,20, $hi +5, $code [0], $FG);
For ($x =0 $x <6; $x + +) {
Imagestring ($img, 5, $LW * (8+ $x *6) +30, $hi +5, $code [$x +1], $FG);
Imagestring ($img, 5, $LW * (53+ $x *6) +30, $hi +5, $code [$x +7], $FG);
}
Imagestring ($img, 4, $LW *95+17, $hi -5, $code [a], $FG);
/* Output the Header and Content. */
Header ("Content-type:image/png");
Imagepng ($IMG);

}

Ean_13 (' 6901028055048 ');

?>