support exporting a plot from an unopened/inactive plugin

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

@@ -73,6 +73,7 @@ class Export(PluginTemplateMixin, ViewerSelectMixin, SubsetSelectMixin,
     dataset_format_items = List().tag(sync=True)
     dataset_format_selected = Unicode().tag(sync=True)
 
+    plugin_plot_selected_widget = Unicode().tag(sync=True)  # copy of widget of the selected plugin_plot in case the parent plugin is not opened
     plugin_plot_format_items = List().tag(sync=True)
     plugin_plot_format_selected = Unicode().tag(sync=True)
 
@@ -438,11 +439,14 @@ 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 +903,13 @@ 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

@@ -4685,12 +4685,14 @@ class Plot(PluginSubcomponent):
     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)
@@ -4748,6 +4750,11 @@ def _remove_data(self, label):
 
         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)
         if label not in self.app.data_collection: