reverse-gif-frames

<?php

//You can try this out at http://home.xtil.net:8000/reversegif/index.php
//It might not be online at all times, though.
//This code is licensed as public domain. Do whatever you want with it.
//Requires Linux, an HTTP server, PHP, and ImageMagick.

if ($_FILES["image"]) {
 if ($_FILES["image"]["error"] <= 0) {
  if ($_FILES["image"]["type"] == "image/gif") {
   $id = rand(100, 999);
   $store = dirname(__FILE__) . "/tmp/";
   move_uploaded_file($_FILES["image"]["tmp_name"], $store . $id . "original.gif");
   exec("convert -coalesce " . $store . $id . "original.gif " . $store . $id . ".png");
   exec("ls -1vr --color=none " . $store . $id . "\-*", $filelist);
   exec("convert -delay " . intval($_POST["framerate"]) . " -loop 0 " . implode(" ", $filelist) . " " . $store . "../reversed/" . $id . ".gif");
   exec("rm " . $store . $id . "*");
   header("Location: reversed/" . $id . ".gif");
  }
  else {
   echo "File should be a gif.";
  }
 }
 else {
  echo "Error " . $_FILES["image"]["error"];
 }
}
else {
?><html><head><title>Reverse GIF</title></head><body>
<p>Here's a quick and easy way to reverse the frame order of an animated GIF. Please download the output image and host it elsewhere, rather than hotlinking!</p>
<form action="index.php" method="post" enctype="multipart/form-data"><fieldset>
Image (max size 1MB): <input type="file" name="image" /><br />
Framerate (centiseconds): <input type="text" name="framerate" value="10" /><br /><input type="submit" value="Reverse it" />
</fieldset></form></body></html><?php
}
?>