bjoern@0: Possible types
bjoern@0: ==============
bjoern@0: 
bjoern@0: * 3D Texture Fill Symbol (deferred)
bjoern@0: * Gradient Fill Symbol
bjoern@0: * Line Fill Symbol
bjoern@0: * Marker Fill Symbol
bjoern@0: * Picture Fill Symbol
bjoern@0: * Simple Fill Symbol