diff --git a/app/imagetransform.cpp b/app/imagetransform.cpp
index cc0dc04..163278e 100644
--- a/app/imagetransform.cpp
+++ b/app/imagetransform.cpp
@@ -1,101 +1,98 @@
 /************************************************************************
  *									*
  *  This file is part of Kooka, a scanning/OCR application using	*
  *  Qt <http://www.qt.io> and KDE Frameworks <http://www.kde.org>.	*
  *									*
  *  Copyright (C) 2013-2016 Jonathan Marten <jjm@keelhaul.me.uk>	*
  *									*
  *  Kooka is free software; you can redistribute it and/or modify it	*
  *  under the terms of the GNU Library General Public License as	*
  *  published by the Free Software Foundation and appearing in the	*
  *  file COPYING included in the packaging of this file;  either	*
  *  version 2 of the License, or (at your option) any later version.	*
  *									*
  *  As a special exception, permission is given to link this program	*
  *  with any version of the KADMOS OCR/ICR engine (a product of		*
  *  reRecognition GmbH, Kreuzlingen), and distribute the resulting	*
  *  executable without including the source code for KADMOS in the	*
  *  source distribution.						*
  *									*
  *  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 General Public License for more details.			*
  *									*
  *  You should have received a copy of the GNU General Public		*
  *  License along with this program;  see the file COPYING.  If		*
  *  not, see <http://www.gnu.org/licenses/>.				*
  *									*
  ************************************************************************/
 
 #include "imagetransform.h"
 
 #include <qurl.h>
 #include <qdebug.h>
 
 #include <klocalizedstring.h>
 
 
 ImageTransform::ImageTransform(const QImage &img, ImageTransform::Operation op,
-                               const QString fileName, QObject *parent)
+                               const QString &fileName, QObject *parent)
     : QThread(parent)
 {
     mImage = img;
     mOperation = op;
     mFileName = fileName;
     //qDebug() << "for operation" << mOperation;
 }
 
-ImageTransform::~ImageTransform()
-{
-}
 
 void ImageTransform::run()
 {
     //qDebug() << "thread started for operation" << mOperation;
 
     QImage resultImg;
     QMatrix m;
 
     switch (mOperation) {
     case ImageTransform::Rotate90:
         emit statusMessage(i18n("Rotate image +90 degrees"));
         m.rotate(+90);
         resultImg = mImage.transformed(m);
         break;
 
     case ImageTransform::MirrorBoth:
     case ImageTransform::Rotate180:
         emit statusMessage(i18n("Rotate image 180 degrees"));
         resultImg = mImage.mirrored(true, true);
         break;
 
     case ImageTransform::Rotate270:
         emit statusMessage(i18n("Rotate image -90 degrees"));
         m.rotate(-90);
         resultImg = mImage.transformed(m);
         break;
 
     case ImageTransform::MirrorHorizontal:
         emit statusMessage(i18n("Mirror image horizontally"));
         resultImg = mImage.mirrored(true, false);
         break;
 
     case ImageTransform::MirrorVertical:
         emit statusMessage(i18n("Mirror image vertically"));
         resultImg = mImage.mirrored(false, true);
         break;
 
     default:
         //qDebug() << "Unknown operation" << mOperation;
         break;
     }
 
     if (resultImg.save(mFileName)) {
         emit done(QUrl::fromLocalFile(mFileName));
     } else {
         emit statusMessage(i18n("Error updating image %1", mFileName));
     }
 
     //qDebug() << "thread finished";
 }
diff --git a/app/imagetransform.h b/app/imagetransform.h
index b1b7e9e..dc6ee30 100644
--- a/app/imagetransform.h
+++ b/app/imagetransform.h
@@ -1,71 +1,71 @@
 /************************************************************************
  *									*
  *  This file is part of Kooka, a scanning/OCR application using	*
  *  Qt <http://www.qt.io> and KDE Frameworks <http://www.kde.org>.	*
  *									*
  *  Copyright (C) 2013-2016 Jonathan Marten <jjm@keelhaul.me.uk>	*
  *									*
  *  Kooka is free software; you can redistribute it and/or modify it	*
  *  under the terms of the GNU Library General Public License as	*
  *  published by the Free Software Foundation and appearing in the	*
  *  file COPYING included in the packaging of this file;  either	*
  *  version 2 of the License, or (at your option) any later version.	*
  *									*
  *  As a special exception, permission is given to link this program	*
  *  with any version of the KADMOS OCR/ICR engine (a product of		*
  *  reRecognition GmbH, Kreuzlingen), and distribute the resulting	*
  *  executable without including the source code for KADMOS in the	*
  *  source distribution.						*
  *									*
  *  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 General Public License for more details.			*
  *									*
  *  You should have received a copy of the GNU General Public		*
  *  License along with this program;  see the file COPYING.  If		*
  *  not, see <http://www.gnu.org/licenses/>.				*
  *									*
  ************************************************************************/
 
 #ifndef IMAGETRANSFORM_H
 #define IMAGETRANSFORM_H
 
 #include <qthread.h>
 #include <qimage.h>
 
 class QUrl;
 
 
 class ImageTransform : public QThread
 {
     Q_OBJECT
 
 public:
     enum Operation {
         Rotate90,                   // 90 degrees clockwise
         Rotate180,                  // 180 degrees
         Rotate270,                  // 90 degrees anticlockwise
         MirrorHorizontal,               // mirror horizontally
         MirrorVertical,                 // mirror vertically
         MirrorBoth                  // effectively same as Rotate180
     };
 
     explicit ImageTransform(const QImage &img, ImageTransform::Operation op,
-                   const QString fileName, QObject *parent = nullptr);
-    ~ImageTransform() override;
+                   const QString &fileName, QObject *parent = nullptr);
+    ~ImageTransform() override = default;
 
 signals:
     void statusMessage(const QString &message);
     void done(const QUrl &imageUrl);
 
 protected:
     void run() override;
 
 private:
     ImageTransform::Operation mOperation;
     QString mFileName;
     QImage mImage;
 };
 
 #endif							// IMAGETRANSFORM_H