public void get_allocation (out Allocation allocation)
Retrieves the widget’s allocation.
Note, when implementing a Container: a widget’s allocation will be its “adjusted” allocation, that is, the widget’s parent container typically calls size_allocate with an allocation, and that allocation is then adjusted (to handle margin and alignment for example) before assignment to the widget. get_allocation returns the adjusted allocation that was actually assigned to the widget. The adjusted allocation is guaranteed to be completely contained within the size_allocate allocation, however. So a Container is guaranteed that its children stay inside the assigned bounds, but not that they have exactly the bounds the container assigned. There is no way to get the original allocation assigned by size_allocate, since it isn’t stored; if a container implementation needs that information it will have to track it itself.
a pointer to a Allocation to copy to