ผมสร้าง บาร์โคต จากโคตนี้ครับ แต่พอเอาไปยิงเครื่องอ่านโคต มันไม่อ่านครับ

<?php
//-----------------------------------------------------------------------------
// Startup code
//-----------------------------------------------------------------------------
date_default_timezone_set("Asia/Bangkok");

if(isset($_GET["text"])) $text=$_GET["text"];
if(isset($_GET["format"])) $format=$_GET["format"];
if(isset($_GET["quality"])) $quality=$_GET["quality"];
if(isset($_GET["width"])) $width=$_GET["width"];
if(isset($_GET["height"])) $height=$_GET["height"];
if(isset($_GET["type"])) $type=$_GET["type"];
if(isset($_GET["barcode"])) $barcode=$_GET["barcode"];




if (!isset ($text)) $text = 1;
if (!isset ($type)) $type = 1;
if (empty ($quality)) $quality = 100;
if (empty ($width)) $width = 160;
if (empty ($height)) $height = 80;
if (!empty ($format)) $format = strtoupper ($format);
        else $format="PNG";


switch ($type)
{
        default:
                $type = 1;
        case 1:
                Barcode39 ($barcode, $width, $height, $quality, $format, $text);
                break;          
}


//-----------------------------------------------------------------------------
// Generate a Code 3 of 9 barcode
//-----------------------------------------------------------------------------
function Barcode39 ($barcode, $width, $height, $quality, $format, $text)
{
        switch ($format)
        {
                default:
                        $format = "PNG";
                case "JPEG": 
                        header ("Content-type: image/jpeg");
                        break;
                case "PNG":
                        header ("Content-type: image/png");
                        break;
                case "GIF":
                        header ("Content-type: image/gif");
                        break;
        }


        $im = ImageCreate ($width, $height)
    or die ("Cannot Initialize new GD image stream");
        $White = ImageColorAllocate ($im, 255,255,255);
        $Black = ImageColorAllocate ($im, 0, 0, 0);
        //ImageColorTransparent ($im, $White);
        ImageInterLace ($im, 1);



        $NarrowRatio = 20;
        $WideRatio = 55;
        $QuietRatio = 35;


        $nChars = (strlen($barcode)+2) * ((6 * $NarrowRatio) + (3 * $WideRatio) + ($QuietRatio));
        $Pixels = $width / $nChars;
        $NarrowBar = (int)(20 * $Pixels);
        $WideBar = (int)(55 * $Pixels);
        $QuietBar = (int)(35 * $Pixels);


        $ActualWidth = (($NarrowBar * 6) + ($WideBar*3) + $QuietBar) * (strlen ($barcode)+2);
        
        if (($NarrowBar == 0) || ($NarrowBar == $WideBar) || ($NarrowBar == $QuietBar) || ($WideBar == 0) || ($WideBar == $QuietBar) || ($QuietBar == 0))
        {
                ImageString ($im, 1, 0, 0, "Image is too small!", $Black);
                OutputImage ($im, $format, $quality);
                exit;
        }
        
        $CurrentBarX = (int)(($width - $ActualWidth) / 2);
        $Color = '';
        $BarcodeFull = "".strtoupper ($barcode)."";
        settype ($BarcodeFull, "string");
        
        $FontNum = 12;
        $FontHeight = ImageFontHeight ($FontNum);
        $FontWidth = ImageFontWidth ($FontNum);
        if ($text != 0)
        {
                $CenterLoc = (int)(($width-1) / 2) - (int)(($FontWidth * strlen($BarcodeFull)) / 2);
                ImageString ($im, $FontNum, $CenterLoc, $height-$FontHeight, "$BarcodeFull", $Black);
        }
		else
		{
			$FontHeight=-2;
		}


        for ($i=0; $i<strlen($BarcodeFull); $i++)
        {
                $StripeCode = Code39 ($BarcodeFull[$i]);


                for ($n=0; $n < 9; $n++)
                {
                        if ($Color == $White) $Color = $Black;
                        else $Color = $White;


                        switch ($StripeCode[$n])
                        {
                                case '0':
                                        ImageFilledRectangle ($im, $CurrentBarX, 0, $CurrentBarX+$NarrowBar, $height-1-$FontHeight-2, $Color);
                                        $CurrentBarX += $NarrowBar;
                                        break;


                                case '1':
                                        ImageFilledRectangle ($im, $CurrentBarX, 0, $CurrentBarX+$WideBar, $height-1-$FontHeight-2, $Color);
                                        $CurrentBarX += $WideBar;
                                        break;
                        }
                }


                $Color = $White;
                ImageFilledRectangle ($im, $CurrentBarX, 0, $CurrentBarX+$QuietBar, $height-1-$FontHeight-2, $Color);
                $CurrentBarX += $QuietBar;
        }


        OutputImage ($im, $format, $quality);
}


//-----------------------------------------------------------------------------
// Output an image to the browser
//-----------------------------------------------------------------------------
function OutputImage ($im, $format, $quality)
{
        switch ($format)
        {
                case "JPEG": 
                        ImageJPEG ($im, "", $quality);
                        break;
                case "PNG":
                        ImagePNG ($im);
                        break;
                case "GIF":
                        ImageGIF ($im);
                        break;
        }
}


//-----------------------------------------------------------------------------
// Returns the Code 3 of 9 value for a given ASCII character
//-----------------------------------------------------------------------------
function Code39 ($Asc)
{
        switch ($Asc)
        {
                case ' ':
                        return "011000100";     
                case '$':
                        return "010101000";             
                case '%':
                        return "000101010"; 
                case '*':
                        return "010010100"; // * Start/Stop
                case '+':
                        return "010001010"; 
                case '|':
                        return "010000101"; 
                case '.':
                        return "110000100"; 
                case '/':
                        return "010100010"; 
				case '-':
						return "010000101";
                case '0':
                        return "000110100"; 
                case '1':
                        return "100100001"; 
                case '2':
                        return "001100001"; 
                case '3':
                        return "101100000"; 
                case '4':
                        return "000110001"; 
                case '5':
                        return "100110000"; 
                case '6':
                        return "001110000"; 
                case '7':
                        return "000100101"; 
                case '8':
                        return "100100100"; 
                case '9':
                        return "001100100"; 
                case 'A':
                        return "100001001"; 
                case 'B':
                        return "001001001"; 
                case 'C':
                        return "101001000";
                case 'D':
                        return "000011001";
                case 'E':
                        return "100011000";
                case 'F':
                        return "001011000";
                case 'G':
                        return "000001101";
                case 'H':
                        return "100001100";
                case 'I':
                        return "001001100";
                case 'J':
                        return "000011100";
                case 'K':
                        return "100000011";
                case 'L':
                        return "001000011";
                case 'M':
                        return "101000010";
                case 'N':
                        return "000010011";
                case 'O':
                        return "100010010";
                case 'P':
                        return "001010010";
                case 'Q':
                        return "000000111";
                case 'R':
                        return "100000110";
                case 'S':
                        return "001000110";
                case 'T':
                        return "000010110";
                case 'U':
                        return "110000001";
                case 'V':
                        return "011000001";
                case 'W':
                        return "111000000";
                case 'X':
                        return "010010001";
                case 'Y':
                        return "110010000";
                case 'Z':
                        return "011010000";
                default:
                        return "011000100"; 
        }
}

?>