How to resize an image

<?php
   ob_start();

   function calculate_width_height($width, $height,$width_needed, $height_needed)
   {
      if ($width <= $width_needed and $height <= $height_needed)
      {
         //Estimate if both Width and Height of the image are smaller then
         //the given values for Width and Height
         //if this is true dan keep the original size of the image
         $l_new_width=$width;
         $l_new_height=$height;
      }
      else
      {
         if ($height > $height_needed)
         {
            //If the value of the height of the image is greater then the given value for height
            //then estimate the percentage of the given value for height in relation to
            //the original height value of the image
            //Use this percentage to calculate the new width value for the image
            //in relation to original width value of the image

            $l_percentage_height =$height_needed/($height/100);
            $l_new_width=($width/100)*$l_percentage_height;
            $l_new_height=$height_needed;

            if ($l_new_width > $width_needed)
            {
               //After calculation the new width value can stil be greater then the needed width value
               //do the same calculation as above but then for the width needed

               $l_percentage_width =$width_needed/($width/100);
               $l_new_height=($height/100)*$l_percentage_width;
               $l_new_width=$width_needed;
            }
         }
         else
         {
            //The height value of the image is not greater then the needed height value
            //but original width value of the image is
            //calculate the new values for width and height

            $l_percentage_width =$width_needed/($width/100);
            $l_new_height=($height/100)*$l_percentage_width;
            $l_new_width=$width_needed;

            if ($l_new_height > $height_needed)
            {
               $l_percentage_height =$height_needed/($height/100);
               $l_new_width=($width/100)*$l_percentage_height;
               $l_new_height=$height_needed;
            }
         }


      }
   $calculated_width_height[] = round($l_new_width);
   $calculated_width_height[] = round($l_new_height);
   return $calculated_width_height;
   }


   function resize($filename, $dest, $width, $height, $type=''){
       if(@imagecreatefromgif($filename)){
           $img=imagecreatefromgif($filename);
           $type_r='gif';
       }
       elseif(@imagecreatefromjpeg($filename)){
           $img=imagecreatefromjpeg($filename);
           $type_r='jpg';
       }
       elseif(@imagecreatefrompng($filename)){
           $img=imagecreatefrompng($filename);
           $type_r='png';
       }
       elseif(@imagecreatefromwbmp($filename)){
           $img=imagecreatefromwbmp($filename);
           $type_r='bmp';
       }
       else{
           return 'Cannot open file';
       }
       $type=($type=='')?$type_r:'';
       $img_n= @ imagecreatetruecolor ($width, $height);
       @ imagecopyresampled($img_n, $img, 0, 0, 0, 0, $width, $height, imagesx($img), imagesy($img));
       if($type=='gif'){
           imagegif($img_n, $dest);
       }
       elseif($type=='jpg'){
          @ imagejpeg($img_n, $dest);
       }
       elseif($type=='png'){
          @ imagepng($img_n, $dest);
       }
       elseif($type=='bmp'){
          @ imagewbmp($img_n, $dest);
       }
       Return true;
   }



   function upload_file($root_dir,$file_name,$file_name_tmp,$lc_width,$lc_height)
   {

      $lc_max_filesize=2001000;
      $filesize=filesize($file_name_tmp);
      $sub_server=substr($_SERVER["HTTP_REFERER"],7,9);
      $uploaddir = "/get_on_top/image_resize/uploads";

      if (
         !file_exists($HTTP_SERVER_VARS["DOCUMENT_ROOT"].$uploaddir) ||
         2 != (fileperms($HTTP_SERVER_VARS["DOCUMENT_ROOT"].$uploaddir) & 2) ||
         1 != (fileperms($HTTP_SERVER_VARS["DOCUMENT_ROOT"].$uploaddir) & 1)
         )
      {
         $error="tets";
      }

      $fileext = substr($file_name, -4);

      if (strtolower($fileext) != ".jpg" and strtolower($fileext) != ".gif")
      {
         print "<b>For security reasons only the uploading of .jpg and .gif files is allowed.</b><br>n";
         print "<a href="javascript:history.back();">Click here to go back.</a><br>";
         exit;
      };

      $loc = $uploaddir."/".$file_name;
      $fullloc = $root_dir.$loc;
      $upfile = $file_name_tmp;

      if ($filesize>$lc_max_filesize)
      {
         $lc_message= "File is too big, may not be bigger then 2MB";
      }
      else
      {
         if(move_uploaded_file($upfile, $fullloc))
         {
            chmod($fullloc, 0644);
         }
         else
         {
            die("Error moving "$upfile" to "$fullloc".");
         }

         $test =filesize($fullloc);
      }


      list($original_width, $original_height, $type, $attr) = getimagesize($fullloc);
      list($l_new_width,$l_new_heigth) = calculate_width_height($original_width, $original_height,$lc_width,$lc_height);

      resize($fullloc, $root_dir.$uploaddir."/".$lc_width."_".$lc_height."_".$file_name, $l_new_width, $l_new_heigth);

   $upload_info[] = $lc_message;
   $upload_info[] = $original_width;
   $upload_info[] = $original_height;
   $upload_info[] = $l_new_width;
   $upload_info[] = $l_new_heigth;

   return $upload_info;

   }



?>
<body>
<?php
   $root_dir =$HTTP_SERVER_VARS["DOCUMENT_ROOT"];

   if ($_POST["resize_submit"] == "resize")
   {

      $lc_height           =$_POST["height"];
      $lc_width            =$_POST["width"];

      $day = getdate();
      $minutes = $day['minutes'];
      $temp=gettimeofday();
      $sec=(int)$temp["sec"];

      if (!empty($_FILES["userfile"]["name"]))
      {
         $fileext = substr($_FILES["userfile"]["name"], -4);

         $ffile_name="1_".$minutes."_".$sec.$fileext;

         $tfile_name_tmp=$_FILES["userfile"]["tmp_name"];

         list($lc_upload_message,$original_width,$original_height,$l_new_width,$l_new_height) = upload_file($root_dir,$ffile_name,$tfile_name_tmp,$lc_width,$lc_height);

         if ($lc_upload_message!="")
         {
            echo "error_message".$lc_upload_message;
         }
      }

      ?>
      <form ENCTYPE="multipart/form-data"  action="resize_image.php" method="post">
      <table>
      <tr><td>height              :</td><td><input type="TEXT" name="height" size="10" value="<?php echo $lc_height ; ?>"></td></tr>
      <tr><td>width               :</td><td><input type="TEXT" name="width"  size="10" value="<?php echo $lc_width  ; ?>"></td></tr>
      <tr><td>image to upload     :</td><td><INPUT NAME="userfile" TYPE="file"></td></tr>
      <tr><td><input type="submit" name="resize_submit" value="resize"></td>
      </form>
      </table>

      <table>
      <tr>
      <td><IMG border=0 src="uploads/<?php echo $ffile_name ; ?>" ></td>
      <td  valign=bottom><IMG border=0 src="uploads/<?php echo $lc_width.'_'.$lc_height.'_'.$ffile_name ; ?>" ></td>
      </tr>
      <tr>
      <td><?php echo "org_height:".$original_height." org_width:".$original_width; ?></td>
      <td><?php echo "new_height_".$l_new_height." new_width_".$l_new_width; ?></td>
      </tr>
      </table>

      <?php


   }
   else
   {

      ?>
      <form ENCTYPE="multipart/form-data"  action="resize_image.php" method="post">
      <table>
      <tr><td>height              :</td><td><input type="TEXT" name="height" size="10" ></td></tr>
      <tr><td>width               :</td><td><input type="TEXT" name="width"  size="10" ></td></tr>
      <tr><td>image to upload     :</td><td><INPUT NAME="userfile" TYPE="file"></td></tr>
      <tr><td><input type="submit" name="resize_submit" value="resize"></td>
      </form>
      </table>
      <?php
   }
?>
</body>
</html>
<?php
ob_end_flush();
?>