PHP pie chart not rendering

php pie chart not rendering. why ?

<?php
$rows = array(80, 75, 53, 32, 20);

$sum = array_sum($rows);
for($i = 0; $i < count($rows); $i++) {
  $rows[$i] = intval( round($rows[$i]*360/$sum) );
}

$img =  imagecreatetruecolor(201, 201);
$white = imagecolorallocate($img, 255, 255, 255); 
imagefill($img, 0, 0, $white);

$cx = $cy = 100;
$w = $h = 200;

$start = 0;
foreach ($rows as $value) {
  $color = imagecolorallocate($img, rand(0, 255), rand(0, 255), rand(0, 255)); 
  $angle_sector = $start + $value;
  imagefilledarc($img, $cx, $cy, $w, $h, $start, $angle_sector, $color, "IMG_ARC_PIE || IMG_ARC_EDGED");
  $start += $value;
}
header ("Content-type: image/gif"); 
imagegif($img);                      
?>

why its not rendering ??? i want to get a pie chart for which different colors are generated

source https://stackoverflow.com/questions/72650214/php-pie-chart-not-rendering