Merge pull request #16822 from brunobeltran/compound_path_bug

timhoffm · web-flow · commit 1632a53acc9c · 2020-03-19T01:34:04.000+01:00
fix bug where make_compound_path kept all STOPs
diff --git a/lib/matplotlib/path.py b/lib/matplotlib/path.py
@@ -325,11 +325,13 @@ def make_compound_path_from_polys(cls, XY):
 
     @classmethod
     def make_compound_path(cls, *args):
-        """Make a compound path from a list of Path objects."""
+        """
+        Make a compound path from a list of Path objects. Blindly removes all
+        Path.STOP control points.
+        """
         # Handle an empty list in args (i.e. no args).
         if not args:
             return Path(np.empty([0, 2], dtype=np.float32))
-
         vertices = np.concatenate([x.vertices for x in args])
         codes = np.empty(len(vertices), dtype=cls.code_type)
         i = 0
@@ -340,6 +342,10 @@ def make_compound_path(cls, *args):
             else:
                 codes[i:i + len(path.codes)] = path.codes
             i += len(path.vertices)
+        # remove STOP's, since internal STOPs are a bug
+        not_stop_mask = codes != cls.STOP
+        vertices = vertices[not_stop_mask, :]
+        codes = codes[not_stop_mask]
 
         return cls(vertices, codes)
 
diff --git a/lib/matplotlib/tests/test_path.py b/lib/matplotlib/tests/test_path.py
@@ -147,6 +147,15 @@ def test_make_compound_path_empty():
     assert r.vertices.shape == (0, 2)
 
 
+def test_make_compound_path_stops():
+    zero = [0, 0]
+    paths = 3*[Path([zero, zero], [Path.MOVETO, Path.STOP])]
+    compound_path = Path.make_compound_path(*paths)
+    # the choice to not preserve the terminal STOP is arbitrary, but
+    # documented, so we test that it is in fact respected here
+    assert np.sum(compound_path.codes == Path.STOP) == 0
+
+
 @image_comparison(['xkcd.png'], remove_text=True)
 def test_xkcd():
     np.random.seed(0)
