Varbinary field output is not able to parse by source method of fpdf in php

Good evening..
I Stored an pdf file to varbinary field in Sql Server successfully and retrieved is as it is but my problem is during retrieve i have to put some watermark on it , for that i tried fpdf methods but it didnt parse it so please help me to come out from it


Thanks

Regards
Raghu



What I have tried:

Hide Shrink Copy Code
<?php
require_once('fpdf/fpdf.php');
require_once('fpdi/fpdi.php');
require_once('connection.php');

$strSQL = "SELECT * FROM files WHERE FilesID = '".$_GET["FilesID"]."' ";

$objQuery = sqlsrv_query($strSQL) or die ("Error Query [".$strSQL."]");

$objResult =sqlsrv_fetch_assoc($con,$objQuery);

header("Content-Type: ".$objResult["FilesType"]);

$pdf = new FPDI();

$pdf->AddPage();

$pdf->setSourceFile($objResult["FilesName"]);

$tplIdx = $pdf->importPage(1);

$pdf->useTemplate($tplIdx, 10, 10, 100);

$pdf->SetFont('Helvetica');
$pdf->SetTextColor(255, 0, 0);
$pdf->SetXY(30, 30);
$pdf->Write(0, 'I tried it');

$pdf->Output();
?>