Fix auto-closing in PolyCollection

lib/matplotlib/collections.py

@@ -809,10 +809,10 @@ def set_verts(self, verts, closed=True):
             for xy in verts:
                 if len(xy):
                     if np.ma.isMaskedArray(xy):
-                        xy = np.ma.concatenate([xy, np.zeros((1, 2))])
+                        xy = np.ma.concatenate([xy, xy[0:1]])
                     else:
                         xy = np.asarray(xy)
-                        xy = np.concatenate([xy, np.zeros((1, 2))])
+                        xy = np.concatenate([xy, xy[0:1]])
                     codes = np.empty(xy.shape[0], dtype=mpath.Path.code_type)
                     codes[:] = mpath.Path.LINETO
                     codes[0] = mpath.Path.MOVETO

lib/matplotlib/tests/test_collections.py

@@ -475,6 +475,44 @@ def test_EllipseCollection():
     ax.autoscale_view()
 
 
+@image_comparison(baseline_images=['polycollection_close'],
+                  extensions=['png'], remove_text=True)
+def test_polycollection_close():
+    from mpl_toolkits.mplot3d import Axes3D
+
+    vertsQuad = [
+        [[0., 0.], [0., 1.], [1., 1.], [1., 0.]],
+        [[0., 1.], [2., 3.], [2., 2.], [1., 1.]],
+        [[2., 2.], [2., 3.], [4., 1.], [3., 1.]],
+        [[3., 0.], [3., 1.], [4., 1.], [4., 0.]]]
+
+    fig = plt.figure()
+    ax = Axes3D(fig)
+
+    colors = ['r', 'g', 'b', 'y', 'k']
+    zpos = list(range(5))
+
+    poly = mcollections.PolyCollection(
+        vertsQuad * len(zpos), linewidth=0.25)
+    poly.set_alpha(0.7)
+
+    ## need to have a z-value for *each* polygon = element!
+    zs = []
+    cs = []
+    for z, c in zip(zpos, colors):
+        zs.extend([z] * len(vertsQuad))
+        cs.extend([c] * len(vertsQuad))
+
+    poly.set_color(cs)
+
+    ax.add_collection3d(poly, zs=zs, zdir='y')
+
+    ## axis limit settings:
+    ax.set_xlim3d(0, 4)
+    ax.set_zlim3d(0, 3)
+    ax.set_ylim3d(0, 4)
+
+
 if __name__ == '__main__':
     import nose
     nose.runmodule(argv=['-s', '--with-doctest'], exit=False)