BUG: Cubeviz coordinate display should follow top visible layer

CHANGES.rst

@@ -83,6 +83,9 @@ Cubeviz
 
 - Fixed linking of plugin data to the reference data that was used to create it [#1412]
 
+- Fixed coordinates display not showing the top layer information when multiple
+  layers are loaded into the image viewer. [#1445]
+
 Imviz
 ^^^^^
 

jdaviz/configs/cubeviz/plugins/moment_maps/moment_maps.py

@@ -60,6 +60,8 @@ def vue_calculate_moment(self, *args):
         except ValueError:
             raise ValueError("Moment must be a positive integer")
         # Need transpose to align JWST mirror shape. Not sure why.
+        # TODO: WCS can be grabbed from cube.wcs[:, :, 0] but CCDData will not take it.
+        #       But if we use NDData, glue-astronomy translator fails.
         self.moment = CCDData(analysis.moment(slab, order=n_moment).T)
 
         fname_label = self.dataset_selected.replace("[", "_").replace("]", "")

jdaviz/configs/cubeviz/plugins/moment_maps/tests/test_moment_maps.py

@@ -10,6 +10,11 @@
 def test_moment_calculation(cubeviz_helper, spectrum1d_cube, tmpdir):
     dc = cubeviz_helper.app.data_collection
     cubeviz_helper.load_data(spectrum1d_cube, data_label='test')
+    flux_viewer = cubeviz_helper.app.get_viewer('flux-viewer')
+
+    # Since we are not really displaying, need this to trigger GUI stuff.
+    flux_viewer.shape = (100, 100)
+    flux_viewer.state._set_axes_aspect_ratio(1)
 
     mm = MomentMap(app=cubeviz_helper.app)
     mm.dataset_selected = 'test[FLUX]'
@@ -33,20 +38,29 @@ def test_moment_calculation(cubeviz_helper, spectrum1d_cube, tmpdir):
     assert mm.results_label == 'moment 0'
     assert mm.results_label_overwrite is True
 
+    # Make sure coordinate display works
+    flux_viewer.on_mouse_or_key_event({'event': 'mousemove', 'domain': {'x': 0, 'y': 0}})
+    assert flux_viewer.state.slices == (0, 0, 1)
+    assert flux_viewer.label_mouseover.pixel == 'x=00.0 y=00.0'
+    assert flux_viewer.label_mouseover.value == '+8.00000e+00 Jy'  # Slice 0 has 8 pixels, this is Slice 1  # noqa
+    assert flux_viewer.label_mouseover.world_ra_deg == '204.9997755346'
+    assert flux_viewer.label_mouseover.world_dec_deg == '27.0000999998'
+
+    # Make sure adding it to viewer does not crash.
+    cubeviz_helper.app.add_data_to_viewer('flux-viewer', 'moment 0')
+
     result = dc[1].get_object(cls=CCDData)
     assert result.shape == (4, 2)  # Cube shape is (2, 2, 4)
 
     # FIXME: Need spatial WCS, see https://github.com/spacetelescope/jdaviz/issues/1025
     assert dc[1].coords is None
 
-    # Make sure coordinate display still works
-    flux_viewer = cubeviz_helper.app.get_viewer('flux-viewer')
+    # Make sure coordinate display now show moment map info (no WCS)
     flux_viewer.on_mouse_or_key_event({'event': 'mousemove', 'domain': {'x': 0, 'y': 0}})
-    assert flux_viewer.state.slices == (0, 0, 1)
     assert flux_viewer.label_mouseover.pixel == 'x=00.0 y=00.0'
     assert flux_viewer.label_mouseover.value == '+8.00000e+00 Jy'  # Slice 0 has 8 pixels, this is Slice 1  # noqa
-    assert flux_viewer.label_mouseover.world_ra_deg == '204.9997755346'
-    assert flux_viewer.label_mouseover.world_dec_deg == '27.0000999998'
+    assert flux_viewer.label_mouseover.world_ra_deg == ''
+    assert flux_viewer.label_mouseover.world_dec_deg == ''
 
     assert mm.filename == 'moment0_test_FLUX.fits'  # Auto-populated on calculate.
     mm.filename = str(tmpdir.join(mm.filename))  # But we want it in tmpdir for testing.
@@ -82,5 +96,5 @@ def test_moment_calculation(cubeviz_helper, spectrum1d_cube, tmpdir):
     # Coordinate display should be unaffected.
     assert flux_viewer.label_mouseover.pixel == 'x=00.0 y=00.0'
     assert flux_viewer.label_mouseover.value == '+8.00000e+00 Jy'  # Slice 0 has 8 pixels, this is Slice 1  # noqa
-    assert flux_viewer.label_mouseover.world_ra_deg == '204.9997755346'
-    assert flux_viewer.label_mouseover.world_dec_deg == '27.0000999998'
+    assert flux_viewer.label_mouseover.world_ra_deg == ''
+    assert flux_viewer.label_mouseover.world_dec_deg == ''

jdaviz/configs/cubeviz/plugins/viewers.py

@@ -65,7 +65,8 @@ def on_mouse_or_key_event(self, data):
 
             # Extract first dataset from visible layers and use this for coordinates - the choice
             # of dataset shouldn't matter if the datasets are linked correctly
-            image = visible_layers[0].layer
+            active_layer = visible_layers[-1]
+            image = active_layer.layer
 
             # Extract data coordinates - these are pixels in the reference image
             x = data['domain']['x']
@@ -94,8 +95,8 @@ def on_mouse_or_key_event(self, data):
             # Extract data values at this position.
             # Check if shape is [x, y, z] or [x, y] and show value accordingly.
             if (-0.5 < x < image.shape[0] - 0.5 and -0.5 < y < image.shape[1] - 0.5
-                    and hasattr(visible_layers[0], 'attribute')):
-                attribute = visible_layers[0].attribute
+                    and hasattr(active_layer, 'attribute')):
+                attribute = active_layer.attribute
                 if len(image.shape) == 3:
                     value = image.get_data(attribute)[int(round(x)), int(round(y)),
                                                       self.state.slices[-1]]