Add an object that will be notified of the changes to this node.
observer must be an object deriving from the NodeObserver class. The virtual methods of this object will be called when a corresponding change happens to this node. You can also notify the observer of the node's current state using synthesizeEvents(NodeObserver &).
|observer||The observer object|
Implemented in Inkscape::XML::SimpleNode.
Referenced by Inkscape::Preferences::addObserver().