Merge pull request #1710 from ericpre/improve_triggering_event_when_s…

…etting_axes_manager_indices

Trigger events only once when settings axes manager indices

hyperspy/axes.py

@@ -1087,8 +1087,14 @@ def coordinates(self, coordinates):
                 "The number of coordinates must be equal to the "
                 "navigation dimension that is %i" %
                 self.navigation_dimension)
-        for value, axis in zip(coordinates, self.navigation_axes):
-            axis.value = value
+        changes = False
+        with self.events.indices_changed.suppress():
+            for value, axis in zip(coordinates, self.navigation_axes):
+                changes = changes or (axis.value != value)
+                axis.value = value
+        # Trigger only if the indices are changed
+        if changes:
+            self.events.indices_changed.trigger(obj=self)
 
     @property
     def indices(self):
@@ -1118,8 +1124,14 @@ def indices(self, indices):
                 "The number of indices must be equal to the "
                 "navigation dimension that is %i" %
                 self.navigation_dimension)
-        for index, axis in zip(indices, self.navigation_axes):
-            axis.index = index
+        changes = False
+        with self.events.indices_changed.suppress():
+            for index, axis in zip(indices, self.navigation_axes):
+                changes = changes or (axis.index != index)
+                axis.index = index
+        # Trigger only if the indices are changed
+        if changes:
+            self.events.indices_changed.trigger(obj=self)
 
     def _get_axis_attribute_values(self, attr):
         return [getattr(axis, attr) for axis in self._axes]

hyperspy/tests/axes/test_axes_manager.py

@@ -19,7 +19,7 @@
 
 from unittest import mock
 
-from hyperspy.axes import DataAxis, AxesManager
+from hyperspy.axes import AxesManager
 from hyperspy.signals import BaseSignal, Signal1D, Signal2D
 from numpy import arange
 
@@ -216,3 +216,50 @@ def test_changing_scale_offset(self):
             signal_axis1.low_value, signal_axis1.high_value,
         )
         assert signal_extent == s.axes_manager.signal_extent
+
+
+def test_setting_indices_coordinates():
+    s = Signal1D(arange(1000).reshape(10, 10, 10))
+
+    m = mock.Mock()
+    s.axes_manager.events.indices_changed.connect(m, [])
+
+    # both indices are changed but the event is triggered only once
+    s.axes_manager.indices = (5, 5)
+    assert s.axes_manager.indices == (5, 5)
+    assert m.call_count == 1
+
+    # indices not changed, so the event is not triggered
+    s.axes_manager.indices == (5, 5)
+    assert s.axes_manager.indices == (5, 5)
+    assert m.call_count == 1
+
+    # both indices changed again, call only once
+    s.axes_manager.indices = (2, 3)
+    assert s.axes_manager.indices == (2, 3)
+    assert m.call_count == 2
+
+    # single index changed, call only once
+    s.axes_manager.indices = (2, 2)
+    assert s.axes_manager.indices == (2, 2)
+    assert m.call_count == 3
+
+    # both coordinates are changed but the event is triggered only once
+    s.axes_manager.coordinates = (5, 5)
+    assert s.axes_manager.coordinates == (5, 5)
+    assert m.call_count == 4
+
+    # coordinates not changed, so the event is not triggered
+    s.axes_manager.indices == (5, 5)
+    assert s.axes_manager.indices == (5, 5)
+    assert m.call_count == 4
+
+    # both coordinates changed again, call only once
+    s.axes_manager.coordinates = (2, 3)
+    assert s.axes_manager.coordinates == (2, 3)
+    assert m.call_count == 5
+
+    # single coordinate changed, call only once
+    s.axes_manager.indices = (2, 2)
+    assert s.axes_manager.indices == (2, 2)
+    assert m.call_count == 6