With matplotlib dependency raised to 1.3, remove inlined clipping code

TODO.txt

@@ -1,10 +1,9 @@
 Remember to list any API changes below in `doc/source/api_changes.txt`.
 
 
+
 Version 0.14
 ------------
-* In `skimage._shared._geometry`, remove `clip_to_bbox` and replace with
-  `poly.clip_to_bbox`, if our dependency on Matplotlib is now >= 1.2.
 * Remove deprecated ``ntiles_*` kwargs in ``equalize_adapthist``.
 * Remove deprecated ``skimage.restoration.nl_means_denoising``.
 * Remove deprecated ``skimage.filters.gaussian_filter``.

requirements.txt

@@ -1,4 +1,4 @@
-matplotlib>=1.1.0
+matplotlib>=1.3.1
 numpy>=1.7.2
 scipy>=0.9.0
 six>=1.4

skimage/_shared/_geometry.py

@@ -1,6 +1,7 @@
 __all__ = ['polygon_clip', 'polygon_area']
 
 import numpy as np
+from matplotlib import _path, path, transforms
 
 
 def polygon_clip(rp, cp, r0, c0, r1, c1):
@@ -24,19 +25,11 @@ def polygon_clip(rp, cp, r0, c0, r1, c1):
     AGG 2.4 and exposed in Matplotlib.
 
     """
-    from matplotlib import _path, path, transforms
-
-    # `clip_to_bbox` is included directly from Matplotlib
-    # since it was only included after v1.1
-    def clip_to_bbox(poly_path, bbox, inside=True):
-        verts = _path.clip_path_to_rect(poly_path, bbox, inside)
-        paths = [path.Path(poly) for poly in verts]
-        return poly_path.make_compound_path(*paths)
-
     poly = path.Path(np.vstack((rp, cp)).T, closed=True)
     clip_rect = transforms.Bbox([[r0, c0], [r1, c1]])
-    poly_clipped = clip_to_bbox(poly, clip_rect).to_polygons()[0]
+    poly_clipped = poly.clip_to_bbox(clip_rect).to_polygons()[0]
 
+    # This should be fixed in matplotlib >1.5
     if np.all(poly_clipped[-1] == poly_clipped[-2]):
         poly_clipped = poly_clipped[:-1]