Barcode by TCPDF

[hossamamereg]

i got this code from the TCPDF to show the barcodes. but the page show nothing can any one guide me.
<?php


// Include the main TCPDF library (search for installation path).
require_once('tcpdf_include.php');

// create new PDF document
$pdf = new TCPDF(PDF_PAGE_ORIENTATION, PDF_UNIT, PDF_PAGE_FORMAT, true, 'UTF-8', false);

// set document information
$pdf->SetCreator(PDF_CREATOR);
$pdf->SetAuthor('Nicola Asuni');
$pdf->SetTitle('TCPDF Example 027');
$pdf->SetSubject('TCPDF Tutorial');
$pdf->SetKeywords('TCPDF, PDF, example, test, guide');

// set default header data
$pdf->SetHeaderData(PDF_HEADER_LOGO, PDF_HEADER_LOGO_WIDTH, PDF_HEADER_TITLE.' 027', PDF_HEADER_STRING);

// set header and footer fonts
$pdf->setHeaderFont(Array(PDF_FONT_NAME_MAIN, '', PDF_FONT_SIZE_MAIN));
$pdf->setFooterFont(Array(PDF_FONT_NAME_DATA, '', PDF_FONT_SIZE_DATA));

// set default monospaced font
$pdf->SetDefaultMonospacedFont(PDF_FONT_MONOSPACED);

// set margins
$pdf->SetMargins(PDF_MARGIN_LEFT, PDF_MARGIN_TOP, PDF_MARGIN_RIGHT);
$pdf->SetHeaderMargin(PDF_MARGIN_HEADER);
$pdf->SetFooterMargin(PDF_MARGIN_FOOTER);

// set auto page breaks
$pdf->SetAutoPageBreak(TRUE, PDF_MARGIN_BOTTOM);

// set image scale factor
$pdf->setImageScale(PDF_IMAGE_SCALE_RATIO);

// set some language-dependent strings (optional)
if (@file_exists(dirname(__FILE__).'/lang/eng.php')) {
require_once(dirname(__FILE__).'/lang/eng.php');
$pdf->setLanguageArray($l);
}

// ---------------------------------------------------------

// set a barcode on the page footer
$pdf->setBarcode(date('Y-m-d H:i:s'));

// set font
$pdf->SetFont('helvetica', '', 11);

// add a page
$pdf->AddPage();

// print a message
$txt = "You can also export 1D barcodes in other formats (PNG, SVG, HTML). Check the examples inside the barcodes directory.\n";
$pdf->MultiCell(70, 50, $txt, 0, 'J', false, 1, 125, 30, true, 0, false, true, 0, 'T', false);
$pdf->SetY(30);

// -----------------------------------------------------------------------------

$pdf->SetFont('helvetica', '', 10);

// define barcode style
$style = array(
'position' => '',
'align' => 'C',
'stretch' => false,
'fitwidth' => true,
'cellfitalign' => '',
'border' => true,
'hpadding' => 'auto',
'vpadding' => 'auto',
'fgcolor' => array(0,0,0),
'bgcolor' => false, //array(255,255,255),
'text' => true,
'font' => 'helvetica',
'fontsize' => 8,
'stretchtext' => 4
);

// PRINT VARIOUS 1D BARCODES

// CODE 39 - ANSI MH10.8M-1983 - USD-3 - 3 of 9.
$pdf->Cell(0, 0, 'CODE 39 - ANSI MH10.8M-1983 - USD-3 - 3 of 9', 0, 1);
$pdf->write1DBarcode('CODE 39', 'C39', '', '', '', 18, 0.4, $style, 'N');

$pdf->Ln();

// CODE 39 + CHECKSUM
$pdf->Cell(0, 0, 'CODE 39 + CHECKSUM', 0, 1);
$pdf->write1DBarcode('CODE 39 +', 'C39+', '', '', '', 18, 0.4, $style, 'N');

$pdf->Ln();

// CODE 39 EXTENDED
$pdf->Cell(0, 0, 'CODE 39 EXTENDED', 0, 1);
$pdf->write1DBarcode('CODE 39 E', 'C39E', '', '', '', 18, 0.4, $style, 'N');

$pdf->Ln();

// CODE 39 EXTENDED + CHECKSUM
$pdf->Cell(0, 0, 'CODE 39 EXTENDED + CHECKSUM', 0, 1);
$pdf->write1DBarcode('CODE 39 E+', 'C39E+', '', '', '', 18, 0.4, $style, 'N');