ChartDirector เซตให้ใช้งาน ภาษาไทย ยังไงคับ ลองแก้ตามที่ post ไว้แต่ยังไม่ได้

<?php
require_once("lib/phpchartdir.php");
require_once("configuration/connectiondb.inc.php");

$sid	=	424;
$qid	=	1;
$data = array();
$labels= array();

$sql  =	" SELECT survey_id, question_id, answer_id FROM analysis_of_response ";
$sql .=	" WHERE survey_id = '$sid' AND question_id = '$qid' GROUP BY answer_id ";
$obj 	= mysql_query($sql);

	$sql2	  = " SELECT answer_text FROM survey_answers ";
	$sql2 .= " WHERE survey_id = '$sid' AND question_id = '$qid' ";
	$obj2  = mysql_query($sql2);
	
	$sql3  = " SELECT question_details FROM questions ";
	$sql3 .= " WHERE survey_id = '$sid' ";
	$obj3 = mysql_query($sql3);
	$rw3 = mysql_fetch_array($obj3);
	$title	=	iconv('TIS-620','UTF-8',$rw3['question_details']); // SET กราฟเป็น ภาษาไทย

$i = 0;
$j = 0;
while($rw = mysql_fetch_array($obj)) {

	$data[$i]	= $rw['answer_id'];
	$i++;

}	

while($rw2 = mysql_fetch_array($obj2)){
	$labels[$j] = $rw2['answer_text'];
	$j++;
}	
		
# Create a PieChart object of size 360 x 300 pixels
$c = new PieChart(360, 300);

# Set the center of the pie at (180, 140) and the radius to 100 pixels
$c->setPieSize(180, 140, 100);

# Add a title to the pie chart
$c->addTitle($title);

# Draw the pie in 3D
$c->set3D();

# Set the pie data and the pie labels
$c->setData($data, $labels);

# Explode the 1st sector (index = 0)
$c->setExplode(0);

# Output the chart
header("Content-type: image/png");
print($c->makeChart2(PNG));
?>