Change zoom behaviour on ViewArea:

Now it requires a combination of Ctrl + mouse wheel

source/app/ViewArea.cpp

@@ -109,6 +109,14 @@ void ViewArea::clearMask()
 //     return QSize( w, h );
 // }
 
+Void ViewArea::setZoomFactor( Double f )
+{
+  m_zoomFactor = f;
+
+  updateSize();
+  update();
+}
+
 Void ViewArea::zoomChangeEvent(Double factor, QPoint center )
 {
   Double zoomFactor;
@@ -134,14 +142,6 @@ Void ViewArea::zoomChangeEvent(Double factor, QPoint center )
 
 }
 
-void ViewArea::setZoomFactor( double f )
-{
-  m_zoomFactor = f;
-
-  updateSize();
-  update();
-}
-
 void ViewArea::setMode( ViewMode mode )
 {
   if( m_mode == mode )
@@ -523,13 +523,16 @@ void ViewArea::wheelEvent( QWheelEvent *event )
 {
   Double factor;
 
-  factor = 0.001 * event->delta();
-  if(factor>0)
-    factor=1.25;
-  else
-    factor=0.8;
+  if( event->modifiers() & Qt::ControlModifier )
+  {
+    factor = 0.001 * event->delta();
+    if(factor>0)
+      factor=1.25;
+    else
+      factor=0.8;
+    zoomChangeEvent( factor , event->pos() );
+  }
 
-  zoomChangeEvent( factor , event->pos() );
 }
 
 void ViewArea::mousePressEvent( QMouseEvent *event )
@@ -538,6 +541,10 @@ void ViewArea::mousePressEvent( QMouseEvent *event )
 
   QPoint vpos = windowToView( event->pos() );
 
+  if( event->button() == Qt::MidButton )
+  {
+
+  }
   if( event->button() == Qt::LeftButton )
   {
     if( tool() == NavigationTool )