<?php
  
  /**
   * Save the input as a PNG file
   *
   * PHP versions 4 and 5
   *
   * Copyright (c) 2010-2013 Shinya Muramatsu
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   *
   * @author     Shinya Muramatsu <revulon@gmail.com>
   * @copyright  2010-2013 Shinya Muramatsu
   * @license    http://www.opensource.org/licenses/mit-license.php  MIT License
   * @link       http://flashcanvas.net/
   * @link       http://code.google.com/p/flashcanvas/
   */
  
  if ($_SERVER['REQUEST_METHOD'] === 'POST') {
      if (isset($_GET['filename'])) {
          $filename = $_GET['filename'];
      } else {
          $filename = 'canvas.png';
      }
  
      // Force download
      header('Content-Type: application/octet-stream');
      header('Content-Disposition: attachment; filename="' . $filename . '"');
  
      if (isset($_POST['dataurl'])) {
          // Decode the base64-encoded data
          $data = $_POST['dataurl'];
          $data = substr($data, strpos($data, ',') + 1);
          echo base64_decode($data);
      } else {
          // Output the raw data
          readfile('php://input');
      }
  }