fix FancyArrowPatch picker fails depending on arrowstyle #8384 and update fix based on reviewers' suggestion

zhoubecky · zhoubecky · commit 28bc4f8a5fa5 · 2018-04-01T20:17:32.000-04:00
diff --git a/lib/matplotlib/patches.py b/lib/matplotlib/patches.py
@@ -138,9 +138,18 @@ def contains(self, mouseevent, radius=None):
         if callable(self._contains):
             return self._contains(self, mouseevent)
         radius = self._process_radius(radius)
-        inside = self.get_path().contains_point(
-            (mouseevent.x, mouseevent.y), self.get_transform(), radius)
-        return inside, {}
+        codes = self.get_path().codes
+        vertices = self.get_path().vertices
+        # if the current path is concatenated by multiple sub paths.
+        # get the indexes of the starting code(MOVETO) of all sub paths
+        idxs, = np.where(codes == 1)
+        # Don't split before the first MOVETO.
+        idxs = idxs[1:]
+        return any(
+            subpath.contains_point(
+                (mouseevent.x, mouseevent.y), self.get_transform(), radius)
+            for subpath in map(
+                Path, np.split(vertices, idxs), np.split(codes, idxs))), {}
 
     def contains_point(self, point, radius=None):
         """
diff --git a/lib/matplotlib/tests/baseline_images/test_path/arrow_contains_point.png b/lib/matplotlib/tests/baseline_images/test_path/arrow_contains_point.png
diff --git a/lib/matplotlib/tests/test_path.py b/lib/matplotlib/tests/test_path.py
@@ -6,11 +6,13 @@
 from numpy.testing import assert_array_equal
 import pytest
 
+from matplotlib import patches
 from matplotlib.path import Path
 from matplotlib.patches import Polygon
 from matplotlib.testing.decorators import image_comparison
 import matplotlib.pyplot as plt
 from matplotlib import transforms
+from matplotlib.backend_bases import MouseEvent
 
 
 def test_readonly_path():
@@ -65,6 +67,46 @@ def test_nonlinear_containment():
         ax.transData.transform_point((50, .5)), ax.transData)
 
 
+@image_comparison(
+        baseline_images=['arrow_contains_point'], extensions=['png'],
+        remove_text=True, style='mpl20')
+def test_arrow_contains_point():
+    # fix bug (#8384)
+    fig, ax = plt.subplots()
+    ax.set_xlim((0, 2))
+    ax.set_ylim((0, 2))
+
+    # create an arrow with Curve style
+    arrow = patches.FancyArrowPatch((0.5, 0.25), (1.5, 0.75),
+                                    arrowstyle='->',
+                                    mutation_scale=40)
+    ax.add_patch(arrow)
+    # create an arrow with Bracket style
+    arrow1 = patches.FancyArrowPatch((0.5, 1), (1.5, 1.25),
+                                     arrowstyle=']-[',
+                                     mutation_scale=40)
+    ax.add_patch(arrow1)
+    # create an arrow with other arrow style
+    arrow2 = patches.FancyArrowPatch((0.5, 1.5), (1.5, 1.75),
+                                     arrowstyle='fancy',
+                                     fill=False,
+                                     mutation_scale=40)
+    ax.add_patch(arrow2)
+    patches_list = [arrow, arrow1, arrow2]
+
+    # generate some points
+    X, Y = np.meshgrid(np.arange(0, 2, 0.1),
+                       np.arange(0, 2, 0.1))
+    for k, (x, y) in enumerate(zip(X.ravel(), Y.ravel())):
+        xdisp, ydisp = ax.transData.transform_point([x, y])
+        event = MouseEvent('button_press_event', fig.canvas, xdisp, ydisp)
+        for m, patch in enumerate(patches_list):
+            # set the points to red only if the arrow contains the point
+            inside, res = patch.contains(event)
+            if inside:
+                plt.scatter(x, y, s=5, c="r")
+
+
 @image_comparison(baseline_images=['path_clipping'],
                   extensions=['svg'], remove_text=True)
 def test_path_clipping():
