Merge pull request matplotlib#23888 from lschr/fix_polygonselector_clear

Fix PolygonSelector.clear()

Author: QuLogic

lib/matplotlib/tests/test_widgets.py

@@ -1686,6 +1686,29 @@ def test_polygon_selector_box(ax):
         tool._box.extents, (20.0, 40.0, 30.0, 40.0))
 
 
+def test_polygon_selector_clear_method(ax):
+    onselect = mock.Mock(spec=noop, return_value=None)
+    tool = widgets.PolygonSelector(ax, onselect)
+
+    for result in ([(50, 50), (150, 50), (50, 150), (50, 50)],
+                   [(50, 50), (100, 50), (50, 150), (50, 50)]):
+        for x, y in result:
+            for etype, event_args in polygon_place_vertex(x, y):
+                do_event(tool, etype, **event_args)
+
+        artist = tool._selection_artist
+
+        assert tool._selection_completed
+        assert tool.get_visible()
+        assert artist.get_visible()
+        np.testing.assert_equal(artist.get_xydata(), result)
+        assert onselect.call_args == ((result[:-1],), {})
+
+        tool.clear()
+        assert not tool._selection_completed
+        np.testing.assert_equal(artist.get_xydata(), [(0, 0)])
+
+
 @pytest.mark.parametrize("horizOn", [False, True])
 @pytest.mark.parametrize("vertOn", [False, True])
 def test_MultiCursor(horizOn, vertOn):

lib/matplotlib/widgets.py

@@ -4141,8 +4141,8 @@ def _on_key_release(self, event):
             self._remove_box()
             self.set_visible(True)
 
-    def _draw_polygon(self):
-        """Redraw the polygon based on the new vertex positions."""
+    def _draw_polygon_without_update(self):
+        """Redraw the polygon based on new vertex positions, no update()."""
         xs, ys = zip(*self._xys) if self._xys else ([], [])
         self._selection_artist.set_data(xs, ys)
         self._update_box()
@@ -4155,6 +4155,10 @@ def _draw_polygon(self):
             self._polygon_handles.set_data(xs[:-1], ys[:-1])
         else:
             self._polygon_handles.set_data(xs, ys)
+
+    def _draw_polygon(self):
+        """Redraw the polygon based on the new vertex positions."""
+        self._draw_polygon_without_update()
         self.update()
 
     @property
@@ -4177,6 +4181,11 @@ def verts(self, xys):
             self._add_box()
         self._draw_polygon()
 
+    def _clear_without_update(self):
+        self._selection_completed = False
+        self._xys = [(0, 0)]
+        self._draw_polygon_without_update()
+
 
 class Lasso(AxesWidget):
     """