WIP: How to actually fix this mess

[ci skip] [rtd skip]

CHANGES.rst

@@ -97,7 +97,11 @@ Cubeviz
 Imviz
 ^^^^^
 
-* Do not hide previous results in aperture photometry when there is a failure, but rather show
+- Fixed inaccurate results when aperture photometry is performed on non-reference data
+  that are of a different pixel scale or are rotated w.r.t. the reference data when
+  linked by WCS. [#2154]
+
+- Do not hide previous results in aperture photometry when there is a failure, but rather show
   the failure message within the plugin UI to indicate the shown results are "out of date". [#2112]
 
 Mosviz

jdaviz/configs/default/plugins/subset_plugin/subset_plugin.py

@@ -243,7 +243,7 @@ def vue_recenter_subset(self, *args):
             data = self.dataset.selected_dc_item
             comp = data.get_component(data.main_components[0])
             comp_data = comp.data
-            phot_aperstats = ApertureStats(comp_data, aperture)
+            phot_aperstats = ApertureStats(comp_data, aperture, wcs=data.coords)
 
             # Centroid was calculated in selected data, which might or might not be
             # the reference data. However, Subset is always defined w.r.t.

jdaviz/configs/imviz/plugins/aper_phot_simple/aper_phot_simple.py

@@ -29,6 +29,10 @@
 
 __all__ = ['SimpleAperturePhotometry']
 
+# TODO: This plugin needs to show params wrt ref data because that is how glue
+#       defined it, but then it needs to do internal calculation using region
+#       that took account of the dither.
+
 
 @tray_registry('imviz-aper-phot-simple', label="Imviz Simple Aperture Photometry")
 class SimpleAperturePhotometry(PluginTemplateMixin, DatasetSelectMixin, TableMixin):

jdaviz/core/region_translators.py

@@ -32,7 +32,7 @@ def _get_region_from_spatial_subset(plugin_obj, subset_label):
         The plugin is assumed to have a special setup that gives
         it access to these attributes: ``app`` and ``dataset_selected``.
         The ``app._jdaviz_helper.default_viewer`` attribute must also
-        exist and point to an image viewer that has a ``_get_real_xy``
+        exist and point to an image viewer that has a ``get_link_type``
         method.
 
     subset_label : str
@@ -41,7 +41,8 @@ def _get_region_from_spatial_subset(plugin_obj, subset_label):
     Returns
     -------
     reg : `regions.Region`
-        An equivalent ``regions`` shape.
+        An equivalent ``regions`` shape. This can be a pixel or sky
+        region, so the plugin needs to be able to deal with both.
 
     Raises
     ------
@@ -57,31 +58,21 @@ def _get_region_from_spatial_subset(plugin_obj, subset_label):
         if subset_grp.label == subset_label:
             for sbst in subset_grp.subsets:
                 if sbst.data.label == plugin_obj.dataset_selected:
-
-                    # TODO:
-                    # If dataset_selected is not viewer.state.reference_data
-                    # and they are linked by WCS.
-                    # sky_reg = pix_region.to_sky(wcs)
-                    # and no need for viewer._get_real_xy()
-                    # but we still need the old way for subset_plugin.py.
-                    # Should update docstring above.
-                    # Should update aper phot user docs and tests.
-                    # Turn concept notebook into a new test.
-
                     reg = sbst.data.get_selection_definition(
                         subset_id=subset_label, format='astropy-regions')
+
                     # Works around https://github.com/glue-viz/glue-astronomy/issues/52
-                    # Assume it is always pixel region, not sky region. Even with multiple
-                    # viewers, they all seem to share the same reference image even when it is
-                    # not loaded in all the viewers, so use default viewer.
+                    # Even with multiple viewers, they all seem to share the same
+                    # reference image even when it is not loaded in all the viewers,
+                    # so use default viewer.
                     viewer = plugin_obj.app._jdaviz_helper.default_viewer
+                    link_type = viewer.get_link_type(plugin_obj.dataset_selected)
 
-                    x, y, _, _ = viewer._get_real_xy(
-                        plugin_obj.app.data_collection[plugin_obj.dataset_selected],
-                        reg.center.x, reg.center.y)
-                    reg.center.x = x
-                    reg.center.y = y
-                    return reg
+                    if link_type == 'wcs':
+                        return reg.to_sky(
+                            plugin_obj.app.data_collection[plugin_obj.dataset_selected].coords)
+                    else:  # pixels or self
+                        return reg
     else:
         raise ValueError(f'Subset "{subset_label}" not found')