Nicer API for centering

CHANGES.rst

@@ -8,6 +8,8 @@ New Features
 
 - Spinner in plot options while processing changes to contour settings. [#1794]
 
+- Subset Tools plugin now allows recentering of spatial subset. [#1823]
+
 Cubeviz
 ^^^^^^^
 

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

@@ -226,6 +226,47 @@ def vue_update_subset(self, *args):
             self.hub.broadcast(SnackbarMessage(
                 f"Failed to update Subset: {repr(err)}", color='error', sender=self))
 
+    def get_center(self):
+        # Composite region cannot be edited, so just grab first element.
+        if not self.is_editable or self.subset_types[0] == "Range":  # no-op
+            return
+
+        subset_state = self.subset_select.selected_subset_state
+        sbst_obj = subset_state.roi
+
+        if isinstance(sbst_obj, (CircularROI, EllipticalROI)):
+            cx, cy = sbst_obj.get_center()
+        elif isinstance(sbst_obj, RectangularROI):
+            cx, cy = sbst_obj.center()
+        else:  # pragma: no cover
+            raise NotImplementedError(f'Getting center of {sbst_obj.__class__} is not supported')
+
+        return cx, cy
+
+    def set_center(self, x, y):
+        # Composite region cannot be edited, so just grab first element.
+        if not self.is_editable or self.subset_types[0] == "Range":  # no-op
+            return
+
+        subset_state = self.subset_select.selected_subset_state
+        sbst_obj = subset_state.roi
+
+        if isinstance(sbst_obj, (CircularROI, EllipticalROI)):
+            self._set_value_in_subset_definition(0, "X Center", "value", x)
+            self._set_value_in_subset_definition(0, "Y Center", "value", y)
+        elif isinstance(sbst_obj, RectangularROI):
+            cx, cy = sbst_obj.center()
+            dx = x - cx
+            dy = y - cy
+            self._set_value_in_subset_definition(0, "Xmin", "value", sbst_obj.xmin + dx)
+            self._set_value_in_subset_definition(0, "Xmax", "value", sbst_obj.xmax + dx)
+            self._set_value_in_subset_definition(0, "Ymin", "value", sbst_obj.ymin + dy)
+            self._set_value_in_subset_definition(0, "Ymax", "value", sbst_obj.ymax + dy)
+        else:  # pragma: no cover
+            raise NotImplementedError(f'Recentering of {sbst_obj.__class__} is not supported')
+
+        self.vue_update_subset()
+
     # List of JSON-like dict is nice for front-end but a pain to look up,
     # so we use these helper functions.
 

notebooks/concepts/imviz_edit_subset_programmatic.ipynb

@@ -10,7 +10,6 @@
     "import time\n",
     "\n",
     "import numpy as np\n",
-    "from glue.core.edit_subset_mode import ReplaceMode\n",
     "from regions import PixCoord, CirclePixelRegion, RectanglePixelRegion\n",
     "\n",
     "from jdaviz import Imviz"
@@ -105,23 +104,19 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "plg = subset_tool._obj\n",
+    "\n",
     "for i in range(10):\n",
-    "    subset_tool._obj.subset_selected = 'Subset 1'\n",
-    "    subset_state = subset_tool._obj.subset_select.selected_subset_state\n",
-    "    subset_roi = subset_state.roi\n",
-    "    cur_x, cur_y = subset_roi.center()  # API in glue is inconsistent for this; shape-dependent\n",
-    "    subset_roi.move_to(cur_x + 5, cur_y)\n",
-    "    subset_tool._obj.session.edit_subset_mode._combine_data(subset_state, override_mode=ReplaceMode)\n",
-    "    \n",
+    "    plg.subset_selected = 'Subset 1'\n",
+    "    cur_x, cur_y = plg.get_center()\n",
+    "    plg.set_center(cur_x + 5, cur_y)\n",
+    "\n",
     "    time.sleep(0.5)\n",
     "    \n",
-    "    subset_tool._obj.subset_selected = 'Subset 2'\n",
-    "    subset_state = subset_tool._obj.subset_select.selected_subset_state\n",
-    "    subset_roi = subset_state.roi\n",
-    "    cur_x, cur_y = subset_roi.get_center()  # Circle API is different from rectangle.\n",
-    "    subset_roi.move_to(2, -2)  # For circle, this is delta, not absolute.\n",
-    "    subset_tool._obj.session.edit_subset_mode._combine_data(subset_state, override_mode=ReplaceMode)\n",
-    "    \n",
+    "    plg.subset_selected = 'Subset 2'\n",
+    "    cur_x, cur_y = plg.get_center()\n",
+    "    plg.set_center(cur_x + 2, cur_y - 2)\n",
+    "\n",
     "    time.sleep(0.5)"
    ]
   },