Merge #4107 'pelson/compound_path'

tacaswell · tacaswell · commit 30f9def2737e · 2015-02-16T20:20:00.000-05:00
Merged into master instead of v1.4.x

Conflict was two new test in the same place, kept both.
diff --git a/lib/matplotlib/path.py b/lib/matplotlib/path.py
@@ -335,6 +335,10 @@ 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."""
+        # Handle an empty list in args (i.e. no args).
+        if not args:
+            return Path(np.empty([0, 2], dtype=np.float32))
+
         lengths = [len(x) for x in args]
         total_length = sum(lengths)
 
diff --git a/lib/matplotlib/tests/test_path.py b/lib/matplotlib/tests/test_path.py
@@ -7,7 +7,7 @@
 
 from matplotlib.path import Path
 from matplotlib.patches import Polygon
-from nose.tools import assert_raises
+from nose.tools import assert_raises, assert_equal
 from matplotlib.testing.decorators import image_comparison
 import matplotlib.pyplot as plt
 
@@ -82,6 +82,13 @@ def test_log_transform_with_zero():
     ax.grid(True)
 
 
+def test_make_compound_path_empty():
+    # We should be able to make a compound path with no arguments.
+    # This makes it easier to write generic path based code.
+    r = Path.make_compound_path()
+    assert_equal(r.vertices.shape, (0, 2))
+
+
 if __name__ == '__main__':
     import nose
     nose.runmodule(argv=['-s', '--with-doctest'], exit=False)
