From Stephan Huber,

"attached you'll find some modifications to Producer, osgGA and
osgProducer to enable Mac OS X support for

+ scrollwheels,
+ mightymouse-srollballs
+ new tracking-pads with scroll feature
+ tablet-support (pressure, proximity and pointertype) (Wacom only tested)

I think there was a bug in the windows-implementation of scroll-wheel
support (wrong order of ScrollingMotion-enum, casting problem) which is
fixed now.

The scrollwheel-code is a bit klunky across platforms, some devices on
OS X can report an absolute delta in pixel-coordinates not only the
direction, so for now there is scrollingMotion (which describes the
direction) and scrolldeltax and scrolldeltay. I decided to leave the
scrollingmotion-stuff to not break old code relying on this."

src/osgGA/EventQueue.cpp

@@ -87,6 +87,24 @@ void EventQueue::windowResize(float Xmin, float Ymin, float Xmax, float Ymax)
     addEvent(event);
 }
 
+void EventQueue::penPressure(float pressure)
+{
+    GUIEventAdapter* event = new GUIEventAdapter(*_accumulateEventState);
+    event->setEventType(GUIEventAdapter::PEN_PRESSURE);
+    event->setPenPressure(pressure);
+    
+    addEvent(event);
+}
+
+void EventQueue::penProximity(GUIEventAdapter::TabletPointerType pt, bool isEntering)
+{
+    GUIEventAdapter* event = new GUIEventAdapter(*_accumulateEventState);
+    event->setEventType( (isEntering) ? GUIEventAdapter::PEN_PROXIMITY_ENTER : GUIEventAdapter::PEN_PROXIMITY_LEAVE);
+    event->setTabletPointerType(pt);
+    
+    addEvent(event);
+}
+
 void EventQueue::mouseScroll(GUIEventAdapter::ScrollingMotion sm)
 {
     GUIEventAdapter* event = new GUIEventAdapter(*_accumulateEventState);
@@ -96,6 +114,16 @@ void EventQueue::mouseScroll(GUIEventAdapter::ScrollingMotion sm)
     addEvent(event);
 }
 
+void EventQueue::mouseScroll2D(float x, float y)
+{
+    GUIEventAdapter* event = new GUIEventAdapter(*_accumulateEventState);
+    event->setEventType(GUIEventAdapter::SCROLL);
+    event->setScrollingMotionDelta(x,y);
+    
+    addEvent(event);
+}
+
+
 void EventQueue::mouseWarp(float x, float y)
 {
     _accumulateEventState->setX(x);

src/osgGA/GUIEventAdapter.cpp

@@ -26,10 +26,14 @@ GUIEventAdapter::GUIEventAdapter():
     _Ymax(1.0),
     _mx(0.5),
     _my(0.5),
+    _pressure(0.0),
     _buttonMask(0),
     _modKeyMask(0),
-    _scrollingMotion(SCROLL_DOWN),
-    _mouseYOrientation(Y_INCREASING_DOWNWARDS)
+    _scrollingMotion(SCROLL_NONE),
+    _scrollingDeltaX(0),
+    _scrollingDeltaY(0),
+    _mouseYOrientation(Y_INCREASING_DOWNWARDS),
+    _tabletPointerType(UNKNOWN)
 {}
 
 GUIEventAdapter::GUIEventAdapter(const GUIEventAdapter& rhs):
@@ -44,10 +48,14 @@ GUIEventAdapter::GUIEventAdapter(const GUIEventAdapter& rhs):
     _Ymax(rhs._Ymax),
     _mx(rhs._mx),
     _my(rhs._my),
+    _pressure(rhs._pressure),
     _buttonMask(rhs._buttonMask),
     _modKeyMask(rhs._modKeyMask),
     _scrollingMotion(rhs._scrollingMotion),
-    _mouseYOrientation(rhs._mouseYOrientation)
+    _scrollingDeltaX(rhs._scrollingDeltaX),
+    _scrollingDeltaY(rhs._scrollingDeltaY),
+    _mouseYOrientation(rhs._mouseYOrientation),
+    _tabletPointerType(rhs._tabletPointerType)
 {}
 
 GUIEventAdapter::~GUIEventAdapter()

src/osgProducer/KeyboardMouseCallback.cpp

@@ -25,12 +25,33 @@ void KeyboardMouseCallback::mouseScroll( Producer::KeyboardMouseCallback::Scroll
         switch(sm)
         {
             case(Producer::KeyboardMouseCallback::ScrollNone): break;
+            case(Producer::KeyboardMouseCallback::ScrollLeft): _eventQueue->mouseScroll(osgGA::GUIEventAdapter::SCROLL_LEFT); break;
+            case(Producer::KeyboardMouseCallback::ScrollRight): _eventQueue->mouseScroll(osgGA::GUIEventAdapter::SCROLL_RIGHT); break;
             case(Producer::KeyboardMouseCallback::ScrollUp): _eventQueue->mouseScroll(osgGA::GUIEventAdapter::SCROLL_UP); break;
             case(Producer::KeyboardMouseCallback::ScrollDown): _eventQueue->mouseScroll(osgGA::GUIEventAdapter::SCROLL_DOWN); break;
+            case(Producer::KeyboardMouseCallback::Scroll2D): _eventQueue->mouseScroll(osgGA::GUIEventAdapter::SCROLL_2D); break;
         }
     }
 }
 
+void KeyboardMouseCallback::mouseScroll2D( float x, float y )
+{
+    updateWindowSize();
+    if (_eventQueue.valid()) _eventQueue->mouseScroll2D(x,y);
+}
+
+void KeyboardMouseCallback::penPressure( float pressure ) 
+{
+    updateWindowSize();
+    if (_eventQueue.valid()) _eventQueue->penPressure(pressure);
+}
+
+void KeyboardMouseCallback::penProximity(TabletPointerType pt, bool isEntering)
+{
+    updateWindowSize();
+    if (_eventQueue.valid()) _eventQueue->penProximity((osgGA::GUIEventAdapter::TabletPointerType)pt, isEntering);
+}
+
 void KeyboardMouseCallback::buttonPress( float mx, float my, unsigned int mbutton ) 
 {
     updateWindowSize();