Added Dragger::s/getActivationModKeyMask(..) and Dragger::s/getActivationKeyEvent(...) methods to make it possible to have draggers that only respond when you press a specified modified key or standard key.

Changed the optional dragger in osgvolume to require the shift key to be pressed for the dragger to become active.

examples/osgmanipulator/osgmanipulator.cpp

@@ -98,7 +98,6 @@ osg::Node* addDraggerToScene(osg::Node* scene, const std::string& name)
 
     osgManipulator::Dragger* dragger = createDragger(name);
 
-    dragger->setHandleEvents(true);
 
     osg::Group* root = new osg::Group;
     root->addChild(dragger);
@@ -110,6 +109,17 @@ osg::Node* addDraggerToScene(osg::Node* scene, const std::string& name)
 
     dragger->addTransformUpdating(selection);
 
+    // we want the dragger to handle it's own events automatically
+    dragger->setHandleEvents(true);
+
+    // if we don't set an activation key or mod mask then any mouse click on
+    // the dragger will activate it, however if do define either of ActivationModKeyMask or
+    // and ActivationKeyEvent then you'll have to press either than mod key or the specified key to
+    // be able to activate the dragger when you mouse click on it.  Please note the follow allows
+    // activation if either the ctrl key or the 'a' key is pressed and held down.
+    dragger->setActivationModKeyMask(osgGA::GUIEventAdapter::MODKEY_CTRL);
+    dragger->setActivationKeyEvent('a');
+
     return root;
 }
 

examples/osgvolume/osgvolume.cpp

@@ -1477,6 +1477,7 @@ int main( int argc, char **argv )
 #endif
             dragger->setupDefaultGeometry();
             dragger->setHandleEvents(true);
+            dragger->setActivationModKeyMask(osgGA::GUIEventAdapter::MODKEY_SHIFT);
             dragger->addDraggerCallback(new DraggerVolumeTileCallback(tile.get(), tile->getLocator()));
             dragger->setMatrix(osg::Matrix::translate(0.5,0.5,0.5)*tile->getLocator()->getTransform());