Fix AnnotationBbox picking when it moves offscreen.

QuLogic · QuLogic · commit b85764004c39 · 2020-04-22T01:53:13.000-04:00
If it's drawn once, and then moved directly offscreen (via zoom or pan), then the offset of the box would not be updated, meaning it could be accidentally picked. It's not enough to simply update the location of the box, because children might get picked instead, so disable a pick in `contains` if the annotated point is offscreen, similar to `draw`. Fixes #16946.
diff --git a/lib/matplotlib/offsetbox.py b/lib/matplotlib/offsetbox.py
@@ -1523,6 +1523,11 @@ def contains(self, mouseevent):
         inside, info = self._default_contains(mouseevent)
         if inside is not None:
             return inside, info
+
+        xy_pixel = self._get_position_xy(None)
+        if not self._check_xy(None, xy_pixel):
+            return False, {}
+
         t, tinfo = self.offsetbox.contains(mouseevent)
         #if self.arrow_patch is not None:
         #    a, ainfo=self.arrow_patch.contains(event)
@@ -1641,7 +1646,6 @@ def draw(self, renderer):
             return
 
         xy_pixel = self._get_position_xy(renderer)
-
         if not self._check_xy(renderer, xy_pixel):
             return
 
diff --git a/lib/matplotlib/tests/test_offsetbox.py b/lib/matplotlib/tests/test_offsetbox.py
@@ -7,8 +7,11 @@
 import matplotlib.pyplot as plt
 import matplotlib.patches as mpatches
 import matplotlib.lines as mlines
+from matplotlib.backend_bases import MouseButton
+
 from matplotlib.offsetbox import (
-        AnchoredOffsetbox, DrawingArea, _get_packed_offsets)
+        AnchoredOffsetbox, AnnotationBbox, DrawingArea, OffsetImage, TextArea,
+        _get_packed_offsets)
 
 
 @image_comparison(['offsetbox_clipping'], remove_text=True)
@@ -182,3 +185,59 @@ def test_get_packed_offsets_equal(wd_list, total, sep, expected):
 def test_get_packed_offsets_equal_total_none_sep_none():
     with pytest.raises(ValueError):
         _get_packed_offsets([(1, 0)] * 3, total=None, sep=None, mode='equal')
+
+
+@pytest.mark.parametrize('child_type', ['draw', 'image', 'text'])
+@pytest.mark.parametrize('boxcoords',
+                         ['axes fraction', 'axes pixels', 'axes points',
+                          'data'])
+def test_picking(child_type, boxcoords):
+    # These all take up approximately the same area.
+    if child_type == 'draw':
+        picking_child = DrawingArea(5, 5)
+        picking_child.add_artist(mpatches.Rectangle((0, 0), 5, 5, linewidth=0))
+    elif child_type == 'image':
+        im = np.ones((5, 5))
+        im[2, 2] = 0
+        picking_child = OffsetImage(im)
+    elif child_type == 'text':
+        picking_child = TextArea('\N{Black Square}', textprops={'fontsize': 5})
+    else:
+        assert False, f'Unknown picking child type {child_type}'
+
+    fig, ax = plt.subplots()
+    ab = AnnotationBbox(picking_child, (0.5, 0.5), boxcoords=boxcoords)
+    ab.set_picker(True)
+    ax.add_artist(ab)
+
+    calls = 0
+    def on_pick(event):
+        nonlocal calls
+        if event.artist == ab:
+            calls += 1
+    fig.canvas.mpl_connect('pick_event', on_pick)
+
+    # Annotation should be picked by an event occurring at its center.
+    if boxcoords == 'axes points':
+        x, y = ax.transAxes.transform_point((0, 0))
+        x += 0.5 * fig.dpi / 72
+        y += 0.5 * fig.dpi / 72
+    elif boxcoords == 'axes pixels':
+        x, y = ax.transAxes.transform_point((0, 0))
+        x += 0.5
+        y += 0.5
+    else:
+        x, y = ax.transAxes.transform_point((0.5, 0.5))
+    fig.canvas.draw()
+    calls = 0
+    fig.canvas.button_press_event(x, y, MouseButton.LEFT)
+    assert calls == 1
+
+    # Annotation should *not* be picked by an event at its original center
+    # point when the limits have changed enough to hide the *xy* point.
+    ax.set_xlim(-1, 0)
+    ax.set_ylim(-1, 0)
+    fig.canvas.draw()
+    calls = 0
+    fig.canvas.button_press_event(x, y, MouseButton.LEFT)
+    assert calls == 0
