Add widget→View reverse lookup and app widget hierarchy

mytk/app.py

@@ -112,6 +112,26 @@ def widget(self):
         """
         return self.root
 
+    def widget_hierarchy(self, widget=None):
+        """Return the tkinter widget tree as a nested dict, using only
+        tkinter's built-in winfo_* introspection methods.
+
+        Args:
+            widget: The tkinter widget to root the tree at. Defaults to the
+                application's root window.
+        """
+        if widget is None:
+            widget = self.root
+
+        def node(w):
+            return {
+                "class": w.winfo_class(),      # e.g. "TButton", "TLabel", "Frame"
+                "name": w.winfo_name(),        # last path component
+                "path": str(w),                # full Tk path, e.g. ".!frame.!button2"
+                "children": [node(c) for c in w.winfo_children()],
+            }
+        return node(widget)
+
     @property
     def root(self):
         """Returns the root window widget.

mytk/base.py

@@ -79,6 +79,11 @@ def _bind_destroy_cancel(self):
         """No-op fallback. Overridden by EventCapable when present in the MRO."""
         pass
 
+    @staticmethod
+    def view_for(widget):
+        """Return the mytk View that owns this tkinter widget, or None."""
+        return getattr(widget, "mytk_view", None)
+
     """
     Placing widgets in other widgets
     """
@@ -152,6 +157,8 @@ def grid_into(
             widget = parent.widget
 
         self._bind_destroy_cancel()
+        if self.widget is not None:
+            self.widget.mytk_view = self
         self._apply_background_color()
 
         column = 0
@@ -253,6 +260,8 @@ def pack_into(self, parent, **kwargs):
         self.create_widget(master=parent.widget)
         self.parent = parent
         self._bind_destroy_cancel()
+        if self.widget is not None:
+            self.widget.mytk_view = self
         self._apply_background_color()
 
         if self.widget is not None:
@@ -271,6 +280,8 @@ def place_into(self, parent, x, y, width, height):
         self.create_widget(master=parent.widget)
         self.parent = parent
         self._bind_destroy_cancel()
+        if self.widget is not None:
+            self.widget.mytk_view = self
         self._apply_background_color()
 
         if self.widget is not None:

mytk/tests/testWidgetHierarchy.py

@@ -0,0 +1,70 @@
+import unittest
+
+import envtest
+
+from mytk import *
+
+
+class TestWidget(Base):
+    def create_widget(self, master):
+        self.parent = master
+        self.widget = ttk.Frame(master, width=100, height=100)
+
+
+class TestViewFor(envtest.MyTkTestCase):
+    def test_view_for_returns_owning_view(self):
+        widget = TestWidget()
+        widget.grid_into(self.app.window, row=1, column=0)
+        self.assertIs(Base.view_for(widget.widget), widget)
+
+    def test_view_for_after_pack(self):
+        # The app window already manages slaves with grid, so pack into a
+        # fresh empty container to avoid a geometry-manager conflict.
+        container = View(width=100, height=100)
+        container.grid_into(self.app.window, row=1, column=0)
+        widget = TestWidget()
+        widget.pack_into(container)
+        self.assertIs(Base.view_for(widget.widget), widget)
+
+    def test_view_for_after_place(self):
+        widget = TestWidget()
+        widget.place_into(self.app.window, x=0, y=0, width=50, height=50)
+        self.assertIs(Base.view_for(widget.widget), widget)
+
+    def test_view_for_unknown_widget_returns_none(self):
+        bare = ttk.Frame(self.app.window.widget)
+        self.assertIsNone(Base.view_for(bare))
+
+
+class TestWidgetHierarchy(envtest.MyTkTestCase):
+    def test_hierarchy_defaults_to_root(self):
+        tree = self.app.widget_hierarchy()
+        self.assertEqual(tree["path"], ".")
+        self.assertIn("class", tree)
+        self.assertIn("name", tree)
+        self.assertIsInstance(tree["children"], list)
+
+    def test_hierarchy_includes_added_widget(self):
+        widget = TestWidget()
+        widget.grid_into(self.app.window, row=1, column=0)
+
+        tree = self.app.widget_hierarchy()
+
+        def paths(node):
+            yield node["path"]
+            for child in node["children"]:
+                yield from paths(child)
+
+        self.assertIn(str(widget.widget), list(paths(tree)))
+
+    def test_hierarchy_custom_root(self):
+        widget = TestWidget()
+        widget.grid_into(self.app.window, row=1, column=0)
+
+        tree = self.app.widget_hierarchy(widget.widget)
+        self.assertEqual(tree["path"], str(widget.widget))
+        self.assertEqual(tree["class"], widget.widget.winfo_class())
+
+
+if __name__ == "__main__":
+    unittest.main()