Merge pull request spacetelescope#2168 from bmorris3/viz-those-times

adding support for temporal subsets

(cherry picked from commit d7f28ab)

jdaviz/app.py

@@ -13,6 +13,7 @@
 from astropy.io import fits
 from astropy import units as u
 from astropy.coordinates import Angle
+from astropy.time import Time
 from regions import PixCoord, CirclePixelRegion, RectanglePixelRegion, EllipsePixelRegion
 
 from echo import CallbackProperty, DictCallbackProperty, ListCallbackProperty
@@ -686,8 +687,13 @@ def get_data_from_viewer(self, viewer_reference, data_label=None,
                         if cls is not None:
                             handler, _ = data_translator.get_handler_for(cls)
                             try:
-                                layer_data = handler.to_object(layer_data,
-                                                               statistic=statistic)
+                                if cls == Spectrum1D:
+                                    # if this is a spectrum, apply the `statistic`:
+                                    layer_data = handler.to_object(layer_data,
+                                                                   statistic=statistic)
+                                else:
+                                    # otherwise simply translate to an object:
+                                    layer_data = handler.to_object(layer_data)
                             except IncompatibleAttribute:
                                 continue
 
@@ -878,8 +884,9 @@ def get_subsets(self, subset_name=None, spectral_only=False,
                 all_subsets[label] = None
                 continue
 
-            # Is the subset spectral or spatial?
+            # Is the subset spectral, spatial, temporal?
             is_spectral = self._is_subset_spectral(subset_region)
+            is_temporal = self._is_subset_temporal(subset_region)
 
             # Remove duplicate spectral regions
             if is_spectral and isinstance(subset_region, SpectralRegion):
@@ -903,6 +910,12 @@ def get_subsets(self, subset_name=None, spectral_only=False,
                 else:
                     all_subsets[label] = subset_region
 
+            if not (spectral_only or spatial_only) and is_temporal:
+                if object_only:
+                    all_subsets[label] = [reg['region'] for reg in subset_region]
+                else:
+                    all_subsets[label] = subset_region
+
         all_subset_names = [subset.label for subset in dc.subset_groups]
         if subset_name and subset_name in all_subset_names:
             return all_subsets[subset_name]
@@ -935,6 +948,14 @@ def _is_subset_spectral(self, subset_region):
                 return True
         return False
 
+    def _is_subset_temporal(self, subset_region):
+        if isinstance(subset_region, Time):
+            return True
+        elif isinstance(subset_region, list) and len(subset_region) > 0:
+            if isinstance(subset_region[0]['region'], Time):
+                return True
+        return False
+
     def _remove_duplicate_bounds(self, spec_regions):
         regions_no_dups = None