public void get_allocated_size (out Allocation allocation, out int baseline)
Retrieves the widget’s allocated size.
This function returns the last values passed to size_allocate_with_baseline. The value differs from the size returned in get_allocation in that functions like set_halign can adjust the allocation, but not the value returned by this function.
If a widget is not visible, its allocated size is 0.
a pointer to a Allocation to copy to
a pointer to an integer to copy to