fix: create previews from first page on multi-page documents

changelog/unreleased/41045

@@ -0,0 +1,6 @@
+Bugfix: create previews from first page
+
+On multi-page documents (doc, odt, pdf etc) the preview will now be generated
+from the first page and no longer from the last page.
+
+https://github.com/owncloud/core/pull/41045

lib/private/Preview/Bitmap.php

@@ -83,7 +83,8 @@ public function isAvailable(FileInfo $file) {
 	private function getResizedPreview($stream, $maxX, $maxY) {
 		$bp = new Imagick();
 
-		$bp->readImageFile($stream);
+		# using [0] as file name will tell Imagick to use the first page
+		$bp->readImageFile($stream, '[0]');
 
 		$bp = $this->resize($bp, $maxX, $maxY);
 

lib/private/PreviewManager.php

@@ -327,8 +327,6 @@ protected function registerCoreProviders() {
 		// This library adds imagick support for SVG, WMF, OpenEXR, DjVu and Graphviz:
 
 		if (\extension_loaded('imagick')) {
-			$checkImagick = new \Imagick();
-
 			$imagickProviders = [
 				'SVG'	=> ['mimetype' => '/image\/svg\+xml/', 'class' => '\OC\Preview\SVG'],
 				'TIFF'	=> ['mimetype' => '/image\/tiff/', 'class' => '\OC\Preview\TIFF'],
@@ -348,12 +346,12 @@ protected function registerCoreProviders() {
 					continue;
 				}
 
-				if (\count($checkImagick->queryFormats($queryFormat)) === 1) {
+				if (\count(\Imagick::queryFormats($queryFormat)) === 1) {
 					$this->registerCoreProvider($class, $provider['mimetype']);
 				}
 			}
 
-			if (\count($checkImagick->queryFormats('PDF')) === 1) {
+			if (\count(\Imagick::queryFormats('PDF')) === 1) {
 				// Office previews are only supported if either LibreOffice or OpenOffice is installed on the server
 				if (\OC_Helper::is_function_enabled('shell_exec')) {
 					$officeFound = \is_string($this->config->getSystemValue('preview_libreoffice_path', null));

tests/lib/Preview/PDFTest.php

@@ -0,0 +1,52 @@
+<?php
+/**
+ * @author Olivier Paroz <owncloud@interfasys.ch>
+ *
+ * @copyright Copyright (c) 2018, ownCloud GmbH
+ * @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 lib\Preview;
+
+use OC\Preview\PDF;
+use OCP\Files\NotFoundException;
+use Test\Preview\Provider;
+
+/**
+ * Class SVGTest
+ *
+ * @group DB
+ *
+ * @package Test\Preview
+ */
+class PDFTest extends Provider {
+	/**
+	 * @throws NotFoundException
+	 */
+	public function setUp(): void {
+		if (\count(\Imagick::queryFormats('SVG')) === 1) {
+			parent::setUp();
+
+			$fileName = 'testimage.pdf';
+			$this->imgPath = $this->prepareTestFile($fileName, \OC::$SERVERROOT . '/tests/data/' . $fileName);
+			$this->width = 595;
+			$this->height = 842;
+			$this->provider = new PDF();
+		} else {
+			$this->markTestSkipped('No PDF provider present');
+		}
+	}
+}

tests/lib/Preview/Provider.php

@@ -21,12 +21,14 @@
 
 namespace Test\Preview;
 
+use OC\Preview\TXT;
 use OCP\Files\File;
 use OCP\Files\Node;
 use OCP\Preview\IProvider2;
+use Test\TestCase;
 use Test\Traits\UserTrait;
 
-abstract class Provider extends \Test\TestCase {
+abstract class Provider extends TestCase {
 	use UserTrait;
 
 	/** @var File */
@@ -92,15 +94,10 @@ public function testGetThumbnail($widthAdjustment, $heightAdjustment) {
 		$this->maxWidth = $this->width - $widthAdjustment;
 		$this->maxHeight = $this->height - $heightAdjustment;
 
-		// Testing code
-		/*print_r("w $this->width ");
-		print_r("h $this->height ");
-		print_r("r $ratio ");*/
-
 		$preview = $this->getPreview($this->provider);
 		// The TXT provider uses the max dimensions to create its canvas,
 		// so the ratio will always be the one of the max dimension canvas
-		if (!$this->provider instanceof \OC\Preview\TXT) {
+		if (!$this->provider instanceof TXT) {
 			$this->doesRatioMatch($preview, $ratio);
 		}
 		$this->doesPreviewFit($preview);