perf(tools): avoid quadratic selected-item lookups in item tools and item list

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: PierreRaybaut

plotpy/panels/itemlist.py

@@ -233,9 +233,9 @@ def active_item_changed(self, plot: BasePlot) -> None:
         self.plot = plot
         _block = self.blockSignals(True)
         active = plot.get_active_item()
-        for item in self.items:
+        for row, item in enumerate(self.items):
             title = item.title().text()
-            lw_item = self.item(self.items.index(item))
+            lw_item = self.item(row)
             lw_item.setText(title)
             lw_item.setSelected(item.selected)
             font = lw_item.font()

plotpy/tools/image.py

@@ -416,7 +416,8 @@ def get_supported_items(self, plot: BasePlot) -> list[BaseImageItem]:
             and hasattr(item, "get_zaxis_log_state")
         ]
         if len(items) > 1:
-            items = [item for item in items if item in plot.get_selected_items()]
+            selected = plot.get_selected_items()
+            items = [item for item in items if item in selected]
         if items:
             self.action.setChecked(items[0].get_zaxis_log_state())
         return items

plotpy/tools/item.py

@@ -86,7 +86,8 @@ def get_supported_items(self, plot: BasePlot) -> list:
         if len(all_items) == 1:
             return all_items
         else:
-            return [item for item in all_items if item in plot.get_selected_items()]
+            selected = plot.get_selected_items()
+            return [item for item in all_items if item in selected]
 
     def update_status(self, plot: BasePlot) -> None:
         """