Fix GUI update

and dithered use case

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

@@ -241,7 +241,13 @@ def vue_recenter_subset(self, *args):
         comp_data = comp.data
         phot_aperstats = ApertureStats(comp_data, aperture)
 
-        self.set_center(phot_aperstats.centroid, update=False)
+        # Centroid was calculated in selected data, which might or might not be
+        # the reference data. However, Subset is always defined w.r.t.
+        # the reference data, so we need to convert back.
+        viewer = self.app._jdaviz_helper.default_viewer
+        x, y, _ = viewer._get_real_xy(
+            data, phot_aperstats.xcentroid, phot_aperstats.ycentroid, reverse=True)
+        self.set_center((x, y), update=False)
 
     def get_center(self):
         # Composite region cannot be edited.
@@ -304,6 +310,11 @@ def set_center(self, new_cen, update=False):
 
         if update:
             self.vue_update_subset()
+        else:
+            # Force UI to update on browser without changing the subset.
+            tmp = self.subset_definitions
+            self.subset_definitions = []
+            self.subset_definitions = tmp
 
     # List of JSON-like dict is nice for front-end but a pain to look up,
     # so we use these helper functions.

jdaviz/configs/imviz/plugins/viewers.py

@@ -220,12 +220,15 @@ def on_limits_change(self, *args):
             return
         self.set_compass(self.state.layers[i].layer)
 
-    def _get_real_xy(self, image, x, y):
+    def _get_real_xy(self, image, x, y, reverse=False):
         """Return real (X, Y) position and status in case of dithering.
 
         ``coords_status`` is for ``self.label_mouseover`` coords handling only.
         When `True`, it sets the coords, otherwise it resets.
 
+        ``reverse=True`` is only for internal roundtripping (e.g., centroiding
+        in Subset Tools plugin). Never use this for coordinates display panel.
+
         """
         if data_has_valid_wcs(image):
             # Convert these to a SkyCoord via WCS - note that for other datasets
@@ -235,8 +238,12 @@ def _get_real_xy(self, image, x, y):
                 # Convert X,Y from reference data to the one we are actually seeing.
                 # world_to_pixel return scalar ndarray that we need to convert to float.
                 if self.get_link_type(image.label) == 'wcs':
-                    x, y = list(map(float, image.coords.world_to_pixel(
-                        self.state.reference_data.coords.pixel_to_world(x, y))))
+                    if not reverse:
+                        x, y = list(map(float, image.coords.world_to_pixel(
+                            self.state.reference_data.coords.pixel_to_world(x, y))))
+                    else:
+                        x, y = list(map(float, self.state.reference_data.coords.world_to_pixel(
+                            image.coords.pixel_to_world(x, y))))
                 coords_status = True
             except Exception:
                 coords_status = False

notebooks/concepts/imviz_edit_subset_programmatic.ipynb

@@ -1,5 +1,13 @@
 {
  "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "e23ea362",
+   "metadata": {},
+   "source": [
+    "This concept notebook shows how you can move spatial subsets around in Imviz programmatically."
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -111,6 +119,7 @@
     "    cur_x, cur_y = plg.get_center()\n",
     "    plg.set_center((cur_x + 5, cur_y), update=True)\n",
     "\n",
+    "    # We slow it down so you can see, otherwise this will complete too fast.\n",
     "    time.sleep(0.5)\n",
     "    \n",
     "    plg.subset_selected = 'Subset 2'\n",