From fc81102714b298bd8cf042153f5d2b85c683f2ea Mon Sep 17 00:00:00 2001
From: mpa <mpa@opencascade.com>
Date: Wed, 11 Jun 2014 11:06:57 +0400
Subject: [PATCH] add zoom action when wheel is spinning

---
 src/DependencyTree/DependencyTree_View.cxx | 18 ++++++++++++++++++
 src/DependencyTree/DependencyTree_View.h   |  3 ++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/DependencyTree/DependencyTree_View.cxx b/src/DependencyTree/DependencyTree_View.cxx
index 24d9abae3..884446e6e 100644
--- a/src/DependencyTree/DependencyTree_View.cxx
+++ b/src/DependencyTree/DependencyTree_View.cxx
@@ -36,6 +36,7 @@
 // Qt includes
 #include <QApplication>
 #include <QWidgetAction>
+#include <QWheelEvent>
 
 DependencyTree_View::DependencyTree_View( QWidget* theParent )
 :GraphicsView_ViewPort( theParent ),
@@ -156,6 +157,23 @@ void DependencyTree_View::mouseMoveEvent( QMouseEvent *event )
   }
 }
 
+//=================================================================================
+// function : wheelEvent()
+// purpose  : add zoom action when wheel is spinning
+//=================================================================================
+void DependencyTree_View::wheelEvent( QWheelEvent* event )
+{
+  int inc = 10; // zoom coefficient
+  double cx = width() / 2;
+  double cy = height() / 2;
+  if( event->delta() > 0 )
+    zoom( cx, cy, cx + inc, cy + inc );
+  else
+    zoom( cx, cy, cx - inc, cy - inc );
+
+  QGraphicsView::wheelEvent( event );
+}
+
 //=================================================================================
 // function : getViewName()
 // purpose  : return the name of current view
diff --git a/src/DependencyTree/DependencyTree_View.h b/src/DependencyTree/DependencyTree_View.h
index 29d16bae5..6c606d401 100644
--- a/src/DependencyTree/DependencyTree_View.h
+++ b/src/DependencyTree/DependencyTree_View.h
@@ -54,7 +54,8 @@ public:
   void                    init( GraphicsView_ViewFrame* );
   void                    updateModel( bool = true, bool = true );
 
-  void                    mouseMoveEvent(QMouseEvent *event);
+  void                    mouseMoveEvent(QMouseEvent* event);
+  void                    wheelEvent( QWheelEvent* event );
 
   QString                 getViewName() const;
   int                     getStudyId() const;
-- 
2.39.2