Revert zoom after preview view

docs/cubeviz/displaycubes.rst

@@ -111,6 +111,11 @@ You can also use the subset modes that are explained in the
 :ref:`Spatial Regions <imviz_defining_spatial_regions>`
 section above in the same way you would with the other subset selection tools.
 
+Note that moving the cursor outside of the image viewer or deactivating the spectrum-at-spaxel tool
+will revert the spectrum viewer zoom limits from the zoomed-in preview view to the limits set prior
+to using the tool. Thus it may be necessary to reset the zoom to see any single-spaxel subset spectra
+created using the tool.
+
 .. _cubeviz-display-settings:
 
 Display Settings

jdaviz/configs/cubeviz/plugins/tools.py

@@ -89,25 +89,38 @@ class SpectrumPerSpaxel(SinglePixelRegion):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self._spectrum_viewer = None
+        self._previous_bounds = None
         self._mark = None
         self._data = None
 
+    def _reset_spectrum_viewer_bounds(self):
+        sv_state = self._spectrum_viewer.state
+        sv_state.x_min = self._previous_bounds[0]
+        sv_state.x_max = self._previous_bounds[1]
+        sv_state.y_min = self._previous_bounds[2]
+        sv_state.y_max = self._previous_bounds[3]
+
     def activate(self):
         self.viewer.add_event_callback(self.on_mouse_move, events=['mousemove', 'mouseleave'])
         if self._spectrum_viewer is None:
             self._spectrum_viewer = self.viewer.jdaviz_helper.app.get_viewer('spectrum-viewer')
         if self._mark is None:
             self._mark = PluginLine(self._spectrum_viewer, visible=False)
             self._spectrum_viewer.figure.marks = self._spectrum_viewer.figure.marks + [self._mark,]
+        # Store these so we can revert to previous user-set zoom after preview view
+        sv_state = self._spectrum_viewer.state
+        self._previous_bounds = [sv_state.x_min, sv_state.x_max, sv_state.y_min, sv_state.y_max]
         super().activate()
 
     def deactivate(self):
         self.viewer.remove_event_callback(self.on_mouse_move)
+        self._reset_spectrum_viewer_bounds()
         super().deactivate()
 
     def on_mouse_move(self, data):
         if data['event'] == 'mouseleave':
             self._mark.visible = False
+            self._reset_spectrum_viewer_bounds()
             return
 
         x = int(np.round(data['domain']['x']))