diff --git a/src/worksheetview.cpp b/src/worksheetview.cpp
index 4cfe67a5..706d823b 100644
--- a/src/worksheetview.cpp
+++ b/src/worksheetview.cpp
@@ -1,282 +1,278 @@
 /*
     This program is free software; you can redistribute it and/or
     modify it under the terms of the GNU General Public License
     as published by the Free Software Foundation; either version 2
     of the License, or (at your option) any later version.
 
     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; if not, write to the Free Software
     Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA  02110-1301, USA.
 
     ---
     Copyright (C) 2012 Martin Kuettler <martin.kuettler@gmail.com>
  */
 
 #include "worksheetview.h"
 #include "worksheet.h"
 
 #include <QParallelAnimationGroup>
 #include <QPropertyAnimation>
 #include <QScrollBar>
 
 WorksheetView::WorksheetView(Worksheet* scene, QWidget* parent) : QGraphicsView(scene, parent),
     m_scale(1),
     m_animation(nullptr),
     m_hAnimation(nullptr),
     m_vAnimation(nullptr),
     m_worksheet(scene)
 {
     connect(scene, SIGNAL(sceneRectChanged(const QRectF&)),
             this, SLOT(sceneRectChanged(const QRectF&)));
     setAlignment(Qt::AlignLeft | Qt::AlignTop);
     //setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     setHorizontalScrollBarPolicy(Qt::ScrollBarAsNeeded);
 }
 
-WorksheetView::~WorksheetView()
-{
-}
-
 void WorksheetView::makeVisible(const QRectF& sceneRect)
 {
     const qreal w = viewport()->width();
     const qreal h = viewport()->height();
 
     QRectF rect(m_scale*sceneRect.topLeft(), m_scale*sceneRect.size());
 
     qreal x,y;
     if (m_animation) {
         x = m_hAnimation->endValue().toReal();
         y = m_vAnimation->endValue().toReal();
 
         if (QRectF(x,y,w,h).contains(rect))
             return;
     }
 
     if (horizontalScrollBar())
         x = horizontalScrollBar()->value();
     else
         x = 0;
     if (verticalScrollBar())
         y = verticalScrollBar()->value();
     else
         y = 0;
 
     if (!m_animation && QRectF(x,y,w,h).contains(rect))
         return;
 
     qreal nx, ny;
     if (y > rect.y() || rect.height() > h)
         ny = rect.y();
     else
         ny = rect.y() + rect.height() - h;
     if (rect.x() + rect.width() <= w || x > rect.x())
         nx = 0;
     else
         nx = rect.x() + rect.width() - w;
 
     if (!m_worksheet->animationsEnabled()) {
         if (horizontalScrollBar())
             horizontalScrollBar()->setValue(nx);
         if (verticalScrollBar())
             verticalScrollBar()->setValue(ny);
         return;
     }
 
     if (!m_animation)
         m_animation = new QParallelAnimationGroup(this);
 
     if (horizontalScrollBar()) {
         if (!m_hAnimation) {
             m_hAnimation = new QPropertyAnimation(horizontalScrollBar(),
                                                   "value", this);
             m_hAnimation->setStartValue(horizontalScrollBar()->value());
             nx = qBound(qreal(0.0), nx, qreal(0.0+horizontalScrollBar()->maximum()));
             m_hAnimation->setEndValue(nx);
             m_hAnimation->setDuration(100);
             m_animation->addAnimation(m_hAnimation);
         } else {
             qreal progress = static_cast<qreal>(m_hAnimation->currentTime()) /
                 m_hAnimation->totalDuration();
             QEasingCurve curve = m_hAnimation->easingCurve();
             qreal value = curve.valueForProgress(progress);
             qreal sx = 1/(1-value)*(m_hAnimation->currentValue().toReal() -
                                     value * nx);
             m_hAnimation->setStartValue(sx);
             m_hAnimation->setEndValue(nx);
         }
     } else {
         m_hAnimation = nullptr;
     }
 
     if (verticalScrollBar()) {
         if (!m_vAnimation) {
             m_vAnimation = new QPropertyAnimation(verticalScrollBar(),
                                                   "value", this);
             m_vAnimation->setStartValue(verticalScrollBar()->value());
             ny = qBound(qreal(0.0), ny, qreal(0.0+verticalScrollBar()->maximum()));
             m_vAnimation->setEndValue(ny);
             m_vAnimation->setDuration(100);
             m_animation->addAnimation(m_vAnimation);
         } else {
             qreal progress = static_cast<qreal>(m_vAnimation->currentTime()) /
                 m_vAnimation->totalDuration();
             QEasingCurve curve = m_vAnimation->easingCurve();
             qreal value = curve.valueForProgress(progress);
             qreal sy = 1/(1-value)*(m_vAnimation->currentValue().toReal() -
                                     value * ny);
             m_vAnimation->setStartValue(sy);
             m_vAnimation->setEndValue(ny);
         }
     } else {
         m_vAnimation = nullptr;
     }
 
     connect(m_animation, &QParallelAnimationGroup::finished, this, &WorksheetView::endAnimation);
     m_animation->start();
 }
 
-bool WorksheetView::isVisible(const QRectF& sceneRect)
+bool WorksheetView::isVisible(const QRectF& sceneRect) const
 {
     const qreal w = viewport()->width();
     const qreal h = viewport()->height();
 
     QRectF rect(m_scale*sceneRect.topLeft(), m_scale*sceneRect.size());
 
     qreal x,y;
     if (m_animation) {
         x = m_hAnimation->endValue().toReal();
         y = m_vAnimation->endValue().toReal();
     } else {
         if (horizontalScrollBar())
             x = horizontalScrollBar()->value();
         else
             x = 0;
         if (verticalScrollBar())
             y = verticalScrollBar()->value();
         else
             y = 0;
     }
 
     return QRectF(x,y,w,h).contains(rect);
 }
 
-bool WorksheetView::isAtEnd()
+bool WorksheetView::isAtEnd() const
 {
     bool atEnd = true;
     if (verticalScrollBar())
         atEnd &= (verticalScrollBar()->value()==verticalScrollBar()->maximum());
     return atEnd;
 }
 
-void WorksheetView::scrollToEnd()
+void WorksheetView::scrollToEnd() const
 {
     if (verticalScrollBar())
         verticalScrollBar()->setValue(verticalScrollBar()->maximum());
 }
 
 void WorksheetView::scrollBy(int dy)
 {
     if (!verticalScrollBar())
         return;
 
     int ny = verticalScrollBar()->value() + dy;
     if (ny < 0)
         ny = 0;
     else if (ny > verticalScrollBar()->maximum())
         ny = verticalScrollBar()->maximum();
 
     int x;
     if (horizontalScrollBar())
         x = horizontalScrollBar()->value();
     else
         x = 0;
 
     const qreal w = viewport()->width() / m_scale;
     const qreal h = viewport()->height() / m_scale;
     makeVisible(QRectF(x, ny, w, h));
 }
 
 void WorksheetView::endAnimation()
 {
     if (!m_animation)
         return;
 
     m_animation->deleteLater();
     m_hAnimation = nullptr;
     m_vAnimation = nullptr;
     m_animation = nullptr;
 }
 
-QPoint WorksheetView::viewCursorPos()
+QPoint WorksheetView::viewCursorPos() const
 {
     return viewport()->mapFromGlobal(QCursor::pos());
 }
 
-QPointF WorksheetView::sceneCursorPos()
+QPointF WorksheetView::sceneCursorPos() const
 {
     return mapToScene(viewCursorPos());
 }
 
-QRectF WorksheetView::viewRect()
+QRectF WorksheetView::viewRect() const
 {
     const qreal w = viewport()->width() / m_scale;
     const qreal h = viewport()->height() / m_scale;
     qreal y = verticalScrollBar()->value();
     qreal x = horizontalScrollBar() ? horizontalScrollBar()->value() : 0;
     return QRectF(x, y, w, h);
 }
 
-void WorksheetView::resizeEvent(QResizeEvent * event)
+void WorksheetView::resizeEvent(QResizeEvent* event)
 {
     QGraphicsView::resizeEvent(event);
     updateSceneSize();
 }
 
-qreal WorksheetView::scaleFactor()
+qreal WorksheetView::scaleFactor() const
 {
     return m_scale;
 }
 
 void WorksheetView::updateSceneSize()
 {
     QSize s = viewport()->size();
     m_worksheet->setViewSize(s.width()/m_scale, s.height()/m_scale, m_scale);
     sendViewRectChange();
 }
 
-void WorksheetView::sceneRectChanged(const QRectF& sceneRect)
+void WorksheetView::sceneRectChanged(const QRectF& sceneRect) const
 {
     Q_UNUSED(sceneRect);
     if (verticalScrollBar())
         connect(verticalScrollBar(), SIGNAL(valueChanged(int)),
                 this, SLOT(sendViewRectChange()), Qt::UniqueConnection);
     if (horizontalScrollBar())
         connect(horizontalScrollBar(), SIGNAL(valueChanged(int)),
                 this, SLOT(sendViewRectChange()), Qt::UniqueConnection);
 }
 
-void WorksheetView::sendViewRectChange()
+void WorksheetView::sendViewRectChange() const
 {
     emit viewRectChanged(viewRect());
 }
 
 void WorksheetView::zoomIn()
 {
     m_scale *= 1.1;
     scale(1.1, 1.1);
     updateSceneSize();
 }
 
 void WorksheetView::zoomOut()
 {
     m_scale /= 1.1;
     scale(1/1.1, 1/1.1);
     updateSceneSize();
 }
diff --git a/src/worksheetview.h b/src/worksheetview.h
index db60af31..677a361e 100644
--- a/src/worksheetview.h
+++ b/src/worksheetview.h
@@ -1,73 +1,69 @@
 /*
     This program is free software; you can redistribute it and/or
     modify it under the terms of the GNU General Public License
     as published by the Free Software Foundation; either version 2
     of the License, or (at your option) any later version.
 
     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; if not, write to the Free Software
     Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA  02110-1301, USA.
 
     ---
     Copyright (C) 2012 Martin Kuettler <martin.kuettler@gmail.com>
  */
 
 #ifndef WORKSHEETVIEW_H
 #define WORKSHEETVIEW_H
 
 #include <QGraphicsView>
 
 class QParallelAnimationGroup;
 class QPropertyAnimation;
 
 class Worksheet;
 
 class WorksheetView : public QGraphicsView
 {
   Q_OBJECT
-  public:
+public:
     WorksheetView(Worksheet* scene, QWidget* parent);
-    ~WorksheetView() override;
 
     void makeVisible(const QRectF& sceneRect);
-    bool isVisible(const QRectF& sceneRect);
-    bool isAtEnd();
-    void scrollToEnd();
+    bool isVisible(const QRectF& sceneRect) const;
+    bool isAtEnd() const;
+    void scrollToEnd() const;
     void scrollBy(int dy);
 
-    QPoint viewCursorPos();
-    QPointF sceneCursorPos();
-
-    QRectF viewRect();
-
-    void resizeEvent(QResizeEvent* event) Q_DECL_OVERRIDE;
-
-    qreal scaleFactor();
-
+    QPoint viewCursorPos() const;
+    QPointF sceneCursorPos() const;
+    QRectF viewRect() const;
+    qreal scaleFactor() const;
     void updateSceneSize();
 
-  Q_SIGNALS:
-    void viewRectChanged(QRectF rect);
+Q_SIGNALS:
+    void viewRectChanged(QRectF rect) const;
 
-  public Q_SLOTS:
+public Q_SLOTS:
     void zoomIn();
     void zoomOut();
     void endAnimation();
-    void sceneRectChanged(const QRectF& sceneRect);
-    void sendViewRectChange();
+    void sceneRectChanged(const QRectF& sceneRect) const;
+    void sendViewRectChange() const;
+
+private:
+    void resizeEvent(QResizeEvent*) override;
 
-  private:
     qreal m_scale;
     QParallelAnimationGroup* m_animation;
     QPropertyAnimation* m_hAnimation;
     QPropertyAnimation* m_vAnimation;
     Worksheet* m_worksheet;
 };
 
 #endif //WORKSHEETVIEW_H