Save and restore camera parameters

glue_wwt/viewer/data_viewer.py

@@ -2,7 +2,11 @@
 
 from __future__ import absolute_import, division, print_function
 
+from astropy.coordinates import SkyCoord
+import astropy.units as u
 from glue.core.coordinates import WCSCoordinates
+from glue.logger import logger
+from pywwt import ViewerNotAvailableError
 
 from .image_layer import WWTImageLayerArtist
 from .table_layer import WWTTableLayerArtist
@@ -25,7 +29,6 @@ class WWTDataViewerBase(object):
     }
 
     _UPDATE_SETTINGS = [
-        "foreground", "background", "foreground_opacity", "galactic",
         "equatorial_grid", "equatorial_grid_color", "equatorial_text",
         "ecliptic_grid", "ecliptic_grid_color", "ecliptic_text",
         "alt_az_grid", "alt_az_grid_color", "alt_az_text",
@@ -37,6 +40,8 @@ class WWTDataViewerBase(object):
         "precession_chart_color"
     ]
 
+    _IMAGERY_UPDATE_SETTINGS = ["foreground", "background", "foreground_opacity", "galactic"]
+
     def __init__(self):
         self._initialize_wwt()
         self._wwt.actual_planet_scale = True
@@ -55,6 +60,7 @@ def _update_wwt(self, force=False, **kwargs):
             self._wwt.solar_system.cosmos = self.state.mode == 'Universe'
             # Only show local stars when not in Universe or Milky Way mode
             self._wwt.solar_system.stars = self.state.mode not in ['Universe', 'Milky Way']
+            force = True
 
         if force or 'constellation_boundaries' in kwargs:
             self._wwt.constellation_boundaries = self.state.constellation_boundaries != 'None'
@@ -65,6 +71,12 @@ def _update_wwt(self, force=False, **kwargs):
                 wwt_attr = self._GLUE_TO_WWT_ATTR_MAP.get(setting, setting)
                 setattr(self._wwt, wwt_attr, getattr(self.state, setting, None))
 
+        show_imagery = self.state.mode == 'Sky'
+        if show_imagery:
+            for setting in self._IMAGERY_UPDATE_SETTINGS:
+                if force or setting in kwargs:
+                    setattr(self._wwt, setting, getattr(self.state, setting, None))
+
     def get_layer_artist(self, cls, **kwargs):
         "In this package, we must override to append the wwt_client argument."
         return cls(self.state, wwt_client=self._wwt, **kwargs)
@@ -84,3 +96,34 @@ def get_data_layer_artist(self, layer=None, layer_state=None):
     def get_subset_layer_artist(self, layer=None, layer_state=None):
         # At some point maybe we'll use different classes for this?
         return self.get_data_layer_artist(layer=layer, layer_state=layer_state)
+
+    def __gluestate__(self, context):
+        state = super(WWTDataViewerBase, self).__gluestate__(context)
+        try:
+            center = self._wwt.get_center()
+            camera = {
+                "ra": center.ra.deg,
+                "dec": center.dec.deg,
+                "fov": self._wwt.get_fov().value
+            }
+            if hasattr(self._wwt, 'get_roll'):
+                camera["roll"] = self._wwt.get_roll().value
+            state["camera"] = camera
+        except ViewerNotAvailableError:
+            logger.error("Unable to export camera parameters as WWT viewer is not responding.")
+        return state
+
+    @classmethod
+    def __setgluestate__(cls, rec, context):
+        viewer = super(WWTDataViewerBase, cls).__setgluestate__(rec, context)
+        if "camera" in rec:
+            camera = rec["camera"]
+            ra = camera.get("ra", 0)
+            dec = camera.get("dec", 0)
+            fov = camera.get("fov", 60)
+            roll = camera.get("roll", None)
+            camera_kwargs = dict(fov=fov * u.deg, instant=True)
+            if hasattr(viewer._wwt, 'get_roll') and roll is not None:
+                camera_kwargs["roll"] = roll * u.deg
+            viewer._wwt.center_on_coordinates(SkyCoord(ra, dec, unit=u.deg), **camera_kwargs)
+        return viewer