Merge pull request #2141 from astrofrog/fix-xatt-yatt

Fix a bug where x_att and y_att could end up being out of sync in image viewer

CHANGES.md

@@ -45,6 +45,8 @@ v0.16.0 (unreleased)
 v0.15.7 (2020-03-12)
 --------------------
 
+* Fix a bug where x_att and y_att could end up being out of sync in image viewer. [#2141]
+
 * Fix bug that caused an infinite loop in the table viewer and caused glue to
   hang if too many incompatible subsets were in a table viewer. [#2105]
 

glue/viewers/image/state.py

@@ -173,6 +173,11 @@ def _reference_data_changed(self, *args):
                         self.yw_att_helper.world_coord = False
                     self._update_combo_att()
                     self._set_default_slices()
+                    # We need to make sure that we update x_att and y_att
+                    # at the same time before any other callbacks get called,
+                    # so we do this here manually.
+                    self._on_xatt_world_change()
+                    self._on_yatt_world_change()
 
     def _layers_changed(self, *args):
 

glue/viewers/image/tests/test_state.py

@@ -333,3 +333,40 @@ def test_too_many_dimensions(self):
 
         with pytest.raises(IncompatibleAttribute):
             self.viewer_state.layers[0].get_sliced_data()
+
+
+def test_update_x_att_and_y_att():
+
+    # Regression test for a bug that caused y_att to not be updated before
+    # events were sent out about x_att changing.
+
+    viewer_state = ImageViewerState()
+
+    data1 = Data(x=np.ones((3, 4, 5)))
+
+    layer_state1 = ImageLayerState(layer=data1, viewer_state=viewer_state)
+    viewer_state.layers.append(layer_state1)
+
+    data2 = Data(x=np.ones((3, 4, 5)))
+
+    layer_state2 = ImageLayerState(layer=data2, viewer_state=viewer_state)
+    viewer_state.layers.append(layer_state2)
+
+    def check_consistency(*args, **kwargs):
+        # Make sure that x_att and y_att are always for same dataset
+        assert viewer_state.x_att.parent is viewer_state.y_att.parent
+
+    viewer_state.add_global_callback(check_consistency)
+    viewer_state.add_callback('x_att', check_consistency)
+    viewer_state.add_callback('y_att', check_consistency)
+    viewer_state.add_callback('x_att_world', check_consistency)
+    viewer_state.add_callback('y_att_world', check_consistency)
+    viewer_state.add_callback('slices', check_consistency)
+
+    viewer_state.reference_data = data1
+    assert viewer_state.x_att is data1.pixel_component_ids[2]
+    assert viewer_state.y_att is data1.pixel_component_ids[1]
+
+    viewer_state.reference_data = data2
+    assert viewer_state.x_att is data2.pixel_component_ids[2]
+    assert viewer_state.y_att is data2.pixel_component_ids[1]