add preview backend for text based files

lib/preview/txt.php

+<?php
+/**
+ * Copyright (c) 2013 Georg Ehrke georg@ownCloud.com
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+class OC_Preview_TXT extends OC_Preview_Provider{
+
+	public function getMimeType(){
+		return '/text\/.*/';
+	}
+
+	public function getThumbnail($path,$maxX,$maxY,$scalingup,$fileview) {
+		$content = $fileview->fopen($path, 'r');
+		$content = stream_get_contents($content);
+
+		$lines = preg_split("/\r\n|\n|\r/", $content);
+		$numoflines = count($lines);
+
+		$fontsize = 5; //5px
+		$linesize = ceil($fontsize * 1.25);
+
+		$image = imagecreate($maxX, $maxY);
+		$imagecolor = imagecolorallocate($image, 255, 255, 255);
+		$textcolor = imagecolorallocate($image, 0, 0, 0);
+
+		foreach($lines as $index => $line){
+			$index = $index + 1;
+
+			$x = (int) 1;
+			$y = (int) ($index * $linesize) - $fontsize;
+
+			imagestring($image, 1, $x, $y, $line, $textcolor);
+
+			if(($index * $linesize) >= $maxY){
+				break;
+			}
+		}
+
+		$image = new \OC_Image($image);
+		
+		if (!$image->valid()) return false;
+
+		return $image;
+	}
+}
+
+OC_Preview::registerProvider('OC_Preview_TXT');
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