$im = imagecreatefromjpeg("best1.jpg");
$im_width = imagesx($im);
$color = ImageColorAllocate($im, 0, 0, 0);
$CENTER_width = $im_width/2;
$size = 20;
$textsize = imagettfbbox($size, 0, "arial.ttf", $student_name);
$left = $CENTER_width-round(($textsize[2]-$textsize[0])/2);
while ($textsize[2] < ($im_width - 250)) {
$size++;
$textsize = imagettfbbox($size, 0, 'arial.ttf', $student_name);
$left = $CENTER_width-round(($textsize[2]-$textsize[0])/2);
if ($size == 65) break;
}
imagettftext($im, $size, 0, $left, 740, $color, 'arial.ttf',$student_name);