Preserve plot options when replacing data from a plugin

CHANGES.rst

@@ -109,6 +109,9 @@ Other Changes and Additions
 
 - Added direct launchers for each config (e.g. ``specviz``) [#1960]
 
+- Replacing existing data from a plugin (e.g., refitting a model with the same label)
+  now preserves the plot options of the data as previously displayed. [#2288]
+
 3.5.1 (unreleased)
 ==================
 

jdaviz/configs/default/plugins/model_fitting/tests/test_plugin.py

@@ -154,6 +154,35 @@ def test_register_cube_model(cubeviz_helper, spectrum1d_cube):
     assert test_label in cubeviz_helper.app.data_collection
 
 
+def test_refit_plot_options(specviz_helper, spectrum1d):
+    specviz_helper.load_data(spectrum1d)
+    modelfit_plugin = specviz_helper.plugins['Model Fitting']
+
+    modelfit_plugin.model_comp_selected = 'Const1D'
+    modelfit_plugin._obj.comp_label = "C"
+    modelfit_plugin._obj.vue_add_model({})
+
+    with pytest.warns(AstropyUserWarning):
+        modelfit_plugin.calculate_fit(add_data=True)
+
+    sv = specviz_helper.app.get_viewer('spectrum-viewer')
+    atts = {"color": "red", "linewidth": 2, "alpha": 0.8}
+    layer_state = [layer.state for layer in sv.layers if layer.layer.label == "model"][0]
+    for att in atts:
+        setattr(layer_state, att, atts[att])
+
+    # Refit using the same name, which will replace the data by default.
+    modelfit_plugin.create_model_component('Linear1D', 'L')
+
+    with pytest.warns(AstropyUserWarning):
+        modelfit_plugin.calculate_fit(add_data=True)
+
+    layer_state = [layer.state for layer in sv.layers if layer.layer.label == "model"][0]
+
+    for att in atts:
+        assert atts[att] == getattr(layer_state, att)
+
+
 def test_user_api(specviz_helper, spectrum1d):
     with warnings.catch_warnings():
         warnings.simplefilter('ignore')

jdaviz/core/template_mixin.py

@@ -1888,6 +1888,10 @@ def add_results_from_plugin(self, data_item, replace=None, label=None):
         Add ``data_item`` to the app's data_collection according to the default or user-provided
         label and adds to any requested viewers.
         """
+
+        # Note that we can only preserve one of percentile or vmin+vmax
+        ignore_attributes = ("layer", "attribute", "percentile")
+
         if self.label_invalid_msg:
             raise ValueError(self.label_invalid_msg)
 
@@ -1899,22 +1903,33 @@ def add_results_from_plugin(self, data_item, replace=None, label=None):
             # entry should be the same as the original entry (to avoid deleting reference data)
             add_to_viewer_refs = []
             add_to_viewer_vis = []
+            preserved_attributes = []
             for viewer_select_item in self.add_to_viewer_items[1:]:
                 # index 0 is for "None"
                 viewer_ref = viewer_select_item['reference']
                 viewer_item = self.app._viewer_item_by_reference(viewer_ref)
                 viewer = self.app.get_viewer(viewer_ref)
-                viewer_loaded_labels = [layer.layer.label for layer in viewer.layers]
-                if label in viewer_loaded_labels:
-                    add_to_viewer_refs.append(viewer_ref)
-                    add_to_viewer_vis.append(label in viewer_item['visible_layers'])
+                for layer in viewer.layers:
+                    if layer.layer.label != label:
+                        continue
+                    else:
+                        add_to_viewer_refs.append(viewer_ref)
+                        add_to_viewer_vis.append(label in viewer_item['visible_layers'])
+                        preserve_these = {}
+                        for att in layer.state.as_dict():
+                            # Can't set cmap_att, size_att, etc
+                            if att not in ignore_attributes and "_att" not in att:
+                                preserve_these[att] = getattr(layer.state, att)
+                        preserved_attributes.append(preserve_these)
         else:
             if self.add_to_viewer_selected == 'None':
                 add_to_viewer_refs = []
                 add_to_viewer_vis = []
+                preserved_attributes = []
             else:
                 add_to_viewer_refs = [self.add_to_viewer_selected]
                 add_to_viewer_vis = [True]
+                preserved_attributes = [{}]
 
         if label in self.app.data_collection:
             for viewer_ref in add_to_viewer_refs:
@@ -1928,18 +1943,25 @@ def add_results_from_plugin(self, data_item, replace=None, label=None):
             data_item.meta['mosviz_row'] = self.app.state.settings['mosviz_row']
         self.app.add_data(data_item, label)
 
-        for viewer_ref, visible in zip(add_to_viewer_refs, add_to_viewer_vis):
+        for viewer_ref, visible, preserved in zip(add_to_viewer_refs, add_to_viewer_vis,
+                                                  preserved_attributes):
             # replace the contents in the selected viewer with the results from this plugin
+            this_viewer = self.app.get_viewer(viewer_ref)
             if replace is not None:
                 this_replace = replace
             else:
-                this_viewer = self.app.get_viewer(viewer_ref)
                 this_replace = isinstance(this_viewer, BqplotImageView)
 
             self.app.add_data_to_viewer(viewer_ref,
                                         label,
                                         visible=visible, clear_other_data=this_replace)
 
+            if preserved != {}:
+                layer_state = [layer.state for layer in this_viewer.layers if
+                               layer.layer.label == label][0]
+                for att in preserved:
+                    setattr(layer_state, att, preserved[att])
+
         # update overwrite warnings, etc
         self._on_label_changed()