<?php
move_uploaded_file($_FILES["file"]["tmp_name"], "tmp.tex");
$dpi = isset($_POST['dpi']) ? intval($_POST['dpi']) : 200;
$output = shell_exec("./tex2png.sh tmp.tex $dpi");

if ($output !== null) {
  $host = $_SERVER['HTTP_HOST'];
  echo "http://$host/$output";
}
?>