Rewrite some zoom functions. Zoom is done in the middle of the image.

source/SubWindowHandle.cpp

@@ -41,7 +41,8 @@ SubWindowHandle::SubWindowHandle( QWidget * parent ) :
   setWidget( m_cScrollArea );
 
   // Create a new interface to show images
-  m_cViewArea = new ViewArea( m_cScrollArea );
+  m_cViewArea = new ViewArea( this );
+  connect(m_cViewArea, SIGNAL(zoomFactorChanged(double)), this, SLOT(adjustScrollBar(double)));
 
   // Define the cViewArea as the widget inside the scroll area
   m_cScrollArea->setWidget( m_cViewArea );
@@ -262,10 +263,7 @@ Void SubWindowHandle::zoomToFit()
 Void SubWindowHandle::scaleView( Double factor )
 {
   Q_ASSERT( m_cViewArea->image() );
-  Double scaleFactor = m_cViewArea->getZoomFactor();
-  scaleFactor *= factor;
-  m_cViewArea->setZoomFactor( scaleFactor );
-  adjustScrollBar( scaleFactor );
+  m_cViewArea->zoomChangeEvent(factor);
 }
 
 Void SubWindowHandle::scaleView( Int width, Int height )
@@ -292,7 +290,7 @@ Void SubWindowHandle::scaleView( const QSize & size )
     scaleView( hfactor );
 }
 
-Void SubWindowHandle::adjustScrollBar( Double factor )
+void SubWindowHandle::adjustScrollBar( double factor )
 {
   QScrollBar *scrollBar = m_cScrollArea->horizontalScrollBar();
   scrollBar->setValue( int( factor * scrollBar->value() + ( ( factor - 1 ) * scrollBar->pageStep() / 2 ) ) );

source/SubWindowHandle.h

@@ -59,6 +59,9 @@ private:
 
   Bool m_bIsPlaying;
 
+private slots:
+  void adjustScrollBar( double factor );
+
 public:
   SubWindowHandle( QWidget * parent = 0 );
   ~SubWindowHandle();
@@ -118,8 +121,6 @@ public:
    */
   Void scaleView( const QSize & size );
 
-  Void adjustScrollBar( Double factor );
-
   Double getScaleFactor()
   {
     return m_cViewArea->getZoomFactor();
@@ -145,6 +146,7 @@ protected:
 
 public Q_SLOTS:
   bool playEvent();
+
 };
 
 }  // NAMESPACE

source/ViewArea.cpp

@@ -104,19 +104,34 @@ Double ViewArea::getZoomFactor()
 //     return QSize( w, h );
 // }
 
+Void ViewArea::zoomChangeEvent(Double factor)
+{
+  Double zoomFactor;
+  Double maxZoom = 10.0;
+  Double minZoom = ( 32.0 / m_pixmap.width() );
+
+  if( ( m_zoomFactor == minZoom ) && (factor < 1 ) )
+    return;
+
+  if( ( m_zoomFactor == maxZoom ) && (factor > 1 ) )
+    return;
+
+  zoomFactor = m_zoomFactor * factor;
+
+  if( zoomFactor < minZoom )
+    zoomFactor = minZoom;
+
+  if( zoomFactor > maxZoom )
+    zoomFactor = maxZoom;
+
+  setZoomFactor( zoomFactor );
+  emit zoomFactorChanged(factor);
+
+}
+
 void ViewArea::setZoomFactor( double f )
 {
-  //if( f == m_zoomFactor )
-    //return;
-
-  if( f < ( 32.0 / m_pixmap.width() ) )
-    f = 32.0 / m_pixmap.width();
-
-  if( f > 10.0 )
-    f = 10.0;
-
   m_zoomFactor = f;
-  //emit( zoomFactorChanged( m_zoomFactor ) );
 
   updateSize();
   update();
@@ -432,12 +447,15 @@ void ViewArea::paintEvent( QPaintEvent *event )
 ////////////////////////////////////////////////////////////////////////////////
 void ViewArea::wheelEvent( QWheelEvent *event )
 {
-  double f;
+  Double factor;
 
-  f = m_zoomFactor + 0.001 * event->delta();
-
-  setZoomFactor( f );
+  factor = 0.001 * event->delta();
+  if(factor>0)
+    factor=1.25;
+  else
+    factor=0.8;
 
+  zoomChangeEvent( factor );
 }
 
 void ViewArea::mousePressEvent( QMouseEvent *event )

source/ViewArea.h

@@ -105,6 +105,7 @@ public:
   void setInputStream( InputStream *stream );
   InputStream* getInputStream();
 
+  Void zoomChangeEvent(Double factor);
   Double getZoomFactor();
 
 //     QSize sizeHint() const;