server/lib/private/preview/image.php

<?php
/**
 * @author Georg Ehrke <georg@owncloud.com>
 * @author Joas Schilling <nickvergessen@owncloud.com>
 * @author Olivier Paroz <github@oparoz.com>
 * @author Robin Appelman <icewind@owncloud.com>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 * @author Thomas Tanghus <thomas@tanghus.net>
 *
 * @copyright Copyright (c) 2016, ownCloud, Inc.
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License, version 3,
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */
namespace OC\Preview;

abstract class Image extends Provider {

	/**
	 * {@inheritDoc}
	 */
	public function getThumbnail($path, $maxX, $maxY, $scalingup, $fileview) {
		//get fileinfo
		$fileInfo = $fileview->getFileInfo($path);
		if (!$fileInfo) {
			return false;
		}

		$maxSizeForImages = \OC::$server->getConfig()->getSystemValue('preview_max_filesize_image', 50);
		$size = $fileInfo->getSize();

		if ($maxSizeForImages !== -1 && $size > ($maxSizeForImages * 1024 * 1024)) {
			return false;
		}

		$image = new \OC_Image();

		$useTempFile = $fileInfo->isEncrypted() || !$fileInfo->getStorage()->isLocal();
		if ($useTempFile) {
			$fileName = $fileview->toTmpFile($path);
		} else {
			$fileName = $fileview->getLocalFile($path);
		}
		$image->loadFromFile($fileName);
		if ($useTempFile) {
			unlink($fileName);
		}
		$image->fixOrientation();
		if ($image->valid()) {
			$image->scaleDownToFit($maxX, $maxY);

			return $image;
		}
		return false;
	}

}