support exporting a plot from an unopened/inactive plugin

CHANGES.rst

@@ -190,6 +190,8 @@ Bug Fixes
 - Display default filepath in Export plugin, re-enable API exporting, enable relative and absolute
   path exports from the UI. [#2896]
 
+- Fixes exporting the stretch histogram from Plot Options before the Plot Options plugin is ever opened. [#2934]
+
 Cubeviz
 ^^^^^^^
 

jdaviz/configs/default/plugins/export/export.py

@@ -73,6 +73,9 @@ class Export(PluginTemplateMixin, ViewerSelectMixin, SubsetSelectMixin,
     dataset_format_items = List().tag(sync=True)
     dataset_format_selected = Unicode().tag(sync=True)
 
+    # copy of widget of the selected plugin_plot in case the parent plugin is not opened
+    plugin_plot_selected_widget = Unicode().tag(sync=True)
+
     plugin_plot_format_items = List().tag(sync=True)
     plugin_plot_format_selected = Unicode().tag(sync=True)
 
@@ -462,11 +465,16 @@ def export(self, filename=None, show_dialog=None, overwrite=False,
             else:
                 filename = None
 
-            with plot._plugin.as_active():
-                # NOTE: could still take some time for the plot itself to update,
-                # for now we'll hardcode a short amount of time for the plot to render any updates
-                time.sleep(0.2)
-                self.save_figure(plot, filename, filetype, show_dialog=show_dialog)
+            if not plot._plugin.is_active:
+                # force an update to the plot.  This requires the plot to have set
+                # update_callback when instantiated
+                plot._update()
+
+                # create a copy of the widget shown off screen to enable rendering
+                # in case one was never created in the parent plugin
+                self.plugin_plot_selected_widget = f'IPY_MODEL_{plot.model_id}'
+
+            self.save_figure(plot, filename, filetype, show_dialog=show_dialog)
 
         elif len(self.plugin_table.selected):
             filetype = self.plugin_table_format.selected

jdaviz/configs/default/plugins/plot_options/plot_options.py

@@ -567,7 +567,8 @@ def state_attr_for_line_visible(state):
                                                    'stretch_params_value', 'stretch_params_sync',
                                                    state_filter=is_image)
 
-        self.stretch_histogram = Plot(self, name='stretch_hist', viewer_type='histogram')
+        self.stretch_histogram = Plot(self, name='stretch_hist', viewer_type='histogram',
+                                      update_callback=self._update_stretch_histogram)
         # Add the stretch bounds tool to the default Plot viewer.
         self.stretch_histogram.tools_nested.append(["jdaviz:stretch_bounds"])
         self.stretch_histogram._initialize_toolbar(["jdaviz:stretch_bounds"])
@@ -886,8 +887,7 @@ def _update_stretch_hist_sync(self, msg={}):
     @observe('is_active', 'layer_selected', 'viewer_selected',
              'stretch_hist_zoom_limits')
     @skip_if_no_updates_since_last_active()
-    @with_spinner('stretch_hist_spinner')
-    def _update_stretch_histogram(self, msg={}):
+    def _request_update_stretch_histogram(self, msg={}):
         if not hasattr(self, 'viewer'):  # pragma: no cover
             # plugin hasn't been fully initialized yet
             return
@@ -903,6 +903,14 @@ def _update_stretch_histogram(self, msg={}):
             # its type
             msg = {}
 
+        # NOTE: this method is separate from _update_stretch_histogram so that
+        # _update_stretch_histogram can be called manually (or from the
+        # update_callback on the Plot object itself) without going through
+        # the skip_if_no_updates_since_last_active check
+        self._update_stretch_histogram(msg)
+
+    @with_spinner('stretch_hist_spinner')
+    def _update_stretch_histogram(self, msg={}):
         if not self.stretch_function_sync.get('in_subscribed_states'):  # pragma: no cover
             # no (image) viewer with stretch function options
             return

jdaviz/core/template_mixin.py

@@ -949,6 +949,7 @@
             self.selected = self._default_text if self._default_text else default_empty
         else:
             self.selected = default_empty
+        self._clear_cache(*self._cached_properties)
 
     def _is_valid_item(self, item, filter_callables={}):
         for valid_filter in self.filters:
@@ -2632,9 +2633,7 @@
         manual_items = [{'label': label} for label in self.manual_options]
         self.items = manual_items + [{'label': k} for k, v in self.plugin.app._plugin_tables.items()
                                      if self._is_valid_item(v._obj)]
-        self._apply_default_selection()
-        # future improvement: only clear cache if the selected data entry was changed?
-        self._clear_cache(*self._cached_properties)
+        self._apply_default_selection(skip_if_current_valid=True)
 
     @cached_property
     def selected_obj(self):
@@ -2747,16 +2746,14 @@
         manual_items = [{'label': label} for label in self.manual_options]
         self.items = manual_items + [{'label': k} for k, v in self.plugin.app._plugin_plots.items()
                                      if self._is_valid_item(v._obj)]
-        self._apply_default_selection()
-        # future improvement: only clear cache if the selected data entry was changed?
+        self._apply_default_selection(skip_if_current_valid=True)
         self._clear_cache(*self._cached_properties)
 
     @cached_property
     def selected_obj(self):
         return self.plugin.app._jdaviz_helper.plugin_plots.get(self.selected)
 
     def _is_valid_item(self, plot):
-
         def not_empty_plot(plot):
             # checks plot.figure.marks to determine if figure is of an empty plot
             # not sure if this is a foolproof way to do this?
@@ -4685,12 +4682,14 @@
     figure = Any().tag(sync=True, **widget_serialization)
     toolbar = Any().tag(sync=True, **widget_serialization)
 
-    def __init__(self, plugin, name='plot', viewer_type='scatter', app=None, *args, **kwargs):
+    def __init__(self, plugin, name='plot', viewer_type='scatter', update_callback=None,
+                 app=None, *args, **kwargs):
         super().__init__(plugin, 'Plot', *args, **kwargs)
         if app is None:
             app = jglue()
 
         self._app = app
+        self._update_callback = update_callback
         self._plugin = plugin
         self._plot_name = name
         self.viewer = app.new_data_viewer(viewer_type, show=False)
@@ -4715,7 +4714,6 @@
         self._initialize_toolbar()
 
         plugin.session.hub.broadcast(PluginPlotAddedMessage(sender=self))
-        plugin.session.hub.broadcast(PluginPlotModifiedMessage(sender=self))
 
     def _initialize_toolbar(self, default_tool_priority=[]):
         self.toolbar = NestedJupyterToolbar(self.viewer, self.tools_nested, default_tool_priority)
@@ -4741,12 +4739,19 @@
                 # https://github.com/astrofrog/fast-histogram/issues/60
                 raise ValueError("histogram requires data entries with length > 1")
 
-    def _remove_data(self, label):
+    def _remove_data(self, label, broadcast=True):
         dc_entry = self.app.data_collection[label]
         self.viewer.remove_data(dc_entry)
         self.app.data_collection.remove(dc_entry)
 
-        self._plugin.session.hub.broadcast(PluginPlotModifiedMessage(sender=self))
+        if broadcast:
+            self._plugin.session.hub.broadcast(PluginPlotModifiedMessage(sender=self))
+
+    def _update(self):
+        # call the update callback, if it exists, on the parent plugin.
+        # This is useful for updating the plot when a plugin is inactive.
+        if self._update_callback is not None:
+            self._update_callback()
 
     def _update_data(self, label, reset_lims=False, **kwargs):
         self._check_valid_components(**kwargs)
@@ -4774,8 +4779,8 @@
                 style_state = self.layers[label].state.as_dict()
             else:
                 style_state = {}
-            self._remove_data(label)
-            self._add_data(label, **kwargs)
+            self._remove_data(label, broadcast=False)
+            self._add_data(label, broadcast=False, **kwargs)
             self.update_style(label, **style_state)
         if reset_lims:
             self.viewer.state.reset_limits()
@@ -4811,7 +4816,7 @@
 
         self._plugin.session.hub.broadcast(PluginPlotModifiedMessage(sender=self))
 
-    def _add_data(self, label, **kwargs):
+    def _add_data(self, label, broadcast=True, **kwargs):
         self._check_valid_components(**kwargs)
         data = Data(label=label, **kwargs)
         dc = self.app.data_collection
@@ -4826,7 +4831,8 @@
             dc.add_link(links)
         self.viewer.add_data(dc_entry)
 
-        self._plugin.session.hub.broadcast(PluginPlotModifiedMessage(sender=self))
+        if broadcast:
+            self._plugin.session.hub.broadcast(PluginPlotModifiedMessage(sender=self))
 
     def _refresh_marks(self):
         # ensure all marks are drawn