Add support for wxEVT_SPIN_[UP|DOWN] events

src/qt/spinbutt.cpp

@@ -20,6 +20,7 @@ public:
 
 private:
     void valueChanged(int value);
+    virtual void stepBy(int steps) wxOVERRIDE; // see QAbstractSpinBox::stepBy()
 };
 
 wxQtSpinButton::wxQtSpinButton( wxWindow *parent, wxSpinButton *handler )
@@ -40,6 +41,26 @@ void wxQtSpinButton::valueChanged(int value)
     }
 }
 
+void wxQtSpinButton::stepBy(int steps)
+{
+    wxSpinButton* handler = GetHandler();
+    if ( !handler )
+        return;
+
+    int eventType = (steps < 0) ? wxEVT_SPIN_DOWN : wxEVT_SPIN_UP;
+    wxSpinEvent directionEvent(eventType, handler->GetId());
+    directionEvent.SetPosition(value());
+    directionEvent.SetInt(value() + steps * singleStep());
+    directionEvent.SetEventObject(handler);
+
+    handler->HandleWindowEvent(directionEvent); // should return value be checked here?
+
+    if ( directionEvent.IsAllowed() )
+    {
+        QSpinBox::stepBy(steps);
+    }
+}
+
 
 wxSpinButton::wxSpinButton() :
     m_qtSpinBox(NULL)