patches.polygon: fix bug in handling of path closing, #1018.

CHANGELOG

@@ -1,3 +1,8 @@
+2012-08-11 Fix path-closing bug in patches.Polygon, so that regardless
+           of whether the path is the initial one or was subsequently
+           set by set_xy(), get_xy() will return a closed path if and
+           only if get_closed() is True.  Thanks to Jacob Vanderplas. - EF
+
 2012-08-05 When a norm is passed to contourf, either or both of the
            vmin, vmax attributes of that norm are now respected.
            Formerly they were respected only if both were

lib/matplotlib/__init__.py

@@ -1020,6 +1020,7 @@ def tk_window_focus():
     'matplotlib.tests.test_delaunay',
     'matplotlib.tests.test_legend',
     'matplotlib.tests.test_colorbar',
+    'matplotlib.tests.test_patches',
     ]
 
 def test(verbosity=1):

lib/matplotlib/patches.py

@@ -767,12 +767,8 @@ def __init__(self, xy, closed=True, **kwargs):
 
         """
         Patch.__init__(self, **kwargs)
-        xy = np.asarray(xy, np.float_)
-        self._path = Path(xy)
         self._closed = closed
-        if closed and len(xy):
-            xy = np.concatenate([xy, [xy[0]]])
-        self._set_xy(xy)
+        self.set_xy(xy)
 
     def get_path(self):
         return self._path
@@ -783,20 +779,22 @@ def get_closed(self):
     def set_closed(self, closed):
         if self._closed == bool(closed):
             return
-        self._closed = closed
-        xy = self._get_xy()
-        if closed:
+        self._closed = bool(closed)
+        self.set_xy(self.get_xy())
+
+    def get_xy(self):
+        return self._path.vertices
+
+    def set_xy(self, xy):
+        xy = np.asarray(xy)
+        if self._closed:
             if len(xy) and (xy[0] != xy[-1]).any():
                 xy = np.concatenate([xy, [xy[0]]])
         else:
             if len(xy)>2 and (xy[0]==xy[-1]).all():
-                xy = xy[0:-1]
-        self._set_xy(xy)
+                xy = xy[:-1]
+        self._path = Path(xy, closed=self._closed)
 
-    def get_xy(self):
-        return self._path.vertices
-    def set_xy(self, vertices):
-        self._path = Path(vertices, closed=self._closed)
     _get_xy = get_xy
     _set_xy = set_xy
     xy = property(

lib/matplotlib/tests/test_patches.py

@@ -0,0 +1,42 @@
+"""
+Tests specific to the patches module.
+"""
+
+from numpy.testing import assert_array_equal
+from matplotlib.patches import Polygon
+
+def test_Polygon_close():
+    """
+    Github issue #1018 identified a bug in the Polygon handling
+    of the closed attribute; the path was not getting closed
+    when set_xy was used to set the vertices.
+    """
+    # open set of vertices:
+    xy = [[0,0], [0,1], [1,1]]
+    # closed set:
+    xyclosed = xy + [[0,0]]
+
+    # start with open path and close it:
+    p = Polygon(xy, closed=True)
+    assert_array_equal(p.get_xy(), xyclosed)
+    p.set_xy(xy)
+    assert_array_equal(p.get_xy(), xyclosed)
+
+    # start with closed path and open it:
+    p = Polygon(xyclosed, closed=False)
+    assert_array_equal(p.get_xy(), xy)
+    p.set_xy(xyclosed)
+    assert_array_equal(p.get_xy(), xy)
+
+    # start with open path and leave it open:
+    p = Polygon(xy, closed=False)
+    assert_array_equal(p.get_xy(), xy)
+    p.set_xy(xy)
+    assert_array_equal(p.get_xy(), xy)
+
+    # start with closed path and leave it closed:
+    p = Polygon(xyclosed, closed=True)
+    assert_array_equal(p.get_xy(), xyclosed)
+    p.set_xy(xyclosed)
+    assert_array_equal(p.get_xy(), xyclosed)
+