BUG: Add pickle support for itk.Matrix and itk.ImageRegion

For dask. Issue #4267.

Wrapping/Generators/Python/PyBase/pyBase.i

@@ -268,6 +268,16 @@ str = str
             msg << "swig_name(" << self->GetIndex() << ", " << self->GetSize()  << ")";
             return msg.str();
     }
+        %pythoncode %{
+    def __getstate__(self):
+        """Get object state, necessary for serialization with pickle."""
+        state = (tuple(self.GetIndex()), tuple(self.GetSize()))
+        return state
+
+    def __setstate__(self, state):
+        """Set object state, necessary for serialization with pickle."""
+        self.__init__(*state)
+        %}
 }
 
 %enddef
@@ -798,6 +808,16 @@ str = str
                 array = itk.array_from_matrix(self)
                 return np.asarray(array, dtype=dtype)
 
+            def __getstate__(self):
+                """Get object state, necessary for serialization with pickle."""
+                import itk
+                state = itk.array_from_matrix(self)
+                return state
+
+            def __setstate__(self, state):
+                """Set object state, necessary for serialization with pickle."""
+                matrix = itk.matrix_from_array(state)
+                self.__init__(matrix)
             %}
         }
 

Wrapping/Generators/Python/Tests/extras.py

@@ -189,6 +189,15 @@ def custom_callback(name, progress):
 )
 assert np.sum(comparison) == 0.0
 
+matrix = itk.Matrix[itk.D, 2, 2]()
+matrix.SetIdentity()
+serialize_deserialize = pickle.loads(pickle.dumps(matrix))
+assert np.array_equal(np.asarray(matrix), np.asarray(serialize_deserialize))
+
+region = itk.ImageRegion[2]([7,8], [2,3])
+serialize_deserialize = pickle.loads(pickle.dumps(region))
+assert region == serialize_deserialize
+
 # Make sure we can read unsigned short, unsigned int, and cast
 image = itk.imread(filename, itk.UI)
 assert type(image) == itk.Image[itk.UI, 2]