Fix #5670. No double endpoints in Path.to_polygon

lib/matplotlib/tests/test_path.py

@@ -10,6 +10,7 @@
 from nose.tools import assert_raises, assert_equal
 from matplotlib.testing.decorators import image_comparison
 import matplotlib.pyplot as plt
+from matplotlib import transforms
 
 
 def test_readonly_path():
@@ -113,6 +114,41 @@ def test_marker_paths_pdf():
     plt.ylim(-1, 7)
 
 
+def test_path_no_doubled_point_in_to_polygon():
+    hand = np.array(
+        [[1.64516129, 1.16145833],
+         [1.64516129, 1.59375],
+         [1.35080645, 1.921875],
+         [1.375, 2.18229167],
+         [1.68548387, 1.9375],
+         [1.60887097, 2.55208333],
+         [1.68548387, 2.69791667],
+         [1.76209677, 2.56770833],
+         [1.83064516, 1.97395833],
+         [1.89516129, 2.75],
+         [1.9516129, 2.84895833],
+         [2.01209677, 2.76041667],
+         [1.99193548, 1.99479167],
+         [2.11290323, 2.63020833],
+         [2.2016129, 2.734375],
+         [2.25403226, 2.60416667],
+         [2.14919355, 1.953125],
+         [2.30645161, 2.36979167],
+         [2.39112903, 2.36979167],
+         [2.41532258, 2.1875],
+         [2.1733871, 1.703125],
+         [2.07782258, 1.16666667]])
+
+    (r0, c0, r1, c1) = (1.0, 1.5, 2.1, 2.5)
+
+    poly = Path(np.vstack((hand[:, 1], hand[:, 0])).T, closed=True)
+    clip_rect = transforms.Bbox([[r0, c0], [r1, c1]])
+    poly_clipped = poly.clip_to_bbox(clip_rect).to_polygons()[0]
+
+    assert np.all(poly_clipped[-2] != poly_clipped[-1])
+    assert np.all(poly_clipped[-1] == poly_clipped[0])
+
+
 if __name__ == '__main__':
     import nose
     nose.runmodule(argv=['-s', '--with-doctest'], exit=False)

lib/matplotlib/tests/test_widgets.py

@@ -162,7 +162,7 @@ def onselect(epress, erelease):
     extents = [int(e) for e in tool.extents]
     assert extents == [70, 129, 70, 130], extents
 
-    assert tool.geometry.shape == (2, 74)
+    assert tool.geometry.shape == (2, 73)
     assert_allclose(tool.geometry[:, 0], [70., 100])
 
 

lib/matplotlib/widgets.py

@@ -245,7 +245,7 @@ def on_clicked(self, func):
         """
         When the button is clicked, call this *func* with event.
 
-        A connection id is returned. It can be used to disconnect 
+        A connection id is returned. It can be used to disconnect
         the button from its callback.
         """
         cid = self.cnt
@@ -265,7 +265,7 @@ class Slider(AxesWidget):
     """
     A slider representing a floating point range.
 
-    For the slider to remain responsive you must maintain a 
+    For the slider to remain responsive you must maintain a
     reference to it.
 
     The following attributes are defined
@@ -2036,7 +2036,7 @@ def geometry(self):
         if hasattr(self.to_draw, 'get_verts'):
             xfm = self.ax.transData.inverted()
             y, x = xfm.transform(self.to_draw.get_verts()).T
-            return np.array([x[:-1], y[:-1]])
+            return np.array([x, y])
         else:
             return np.array(self.to_draw.get_data())
 

src/_path.h

@@ -27,6 +27,16 @@ struct XY
     XY(double x_, double y_) : x(x_), y(y_)
     {
     }
+
+    bool operator==(const XY& o)
+    {
+        return (x == o.x && y == o.y);
+    }
+
+    bool operator!=(const XY& o)
+    {
+        return (x != o.x || y != o.y);
+    }
 };
 
 //
@@ -838,6 +848,25 @@ bool path_intersects_path(PathIterator1 &p1, PathIterator2 &p2)
     return false;
 }
 
+void _finalize_polygon(std::vector<Polygon> &result)
+{
+    Polygon &polygon = result.back();
+
+    if (result.size() == 0) {
+        return;
+    }
+
+    /* Clean up the last polygon in the result.  If less than a
+       triangle, remove it. */
+    if (polygon.size() < 3) {
+        result.pop_back();
+    } else {
+        if (polygon.front() != polygon.back()) {
+            polygon.push_back(polygon.front());
+        }
+    }
+}
+
 template <class PathIterator>
 void convert_path_to_polygons(PathIterator &path,
                               agg::trans_affine &trans,
@@ -867,24 +896,20 @@ void convert_path_to_polygons(PathIterator &path,
 
     while ((code = curve.vertex(&x, &y)) != agg::path_cmd_stop) {
         if ((code & agg::path_cmd_end_poly) == agg::path_cmd_end_poly) {
-            if (polygon->size() >= 1) {
-                polygon->push_back((*polygon)[0]);
-                result.push_back(Polygon());
-                polygon = &result.back();
-            }
+            _finalize_polygon(result);
+            result.push_back(Polygon());
+            polygon = &result.back();
         } else {
-            if (code == agg::path_cmd_move_to && polygon->size() >= 1) {
-                polygon->push_back((*polygon)[0]);
+            if (code == agg::path_cmd_move_to) {
+                _finalize_polygon(result);
                 result.push_back(Polygon());
                 polygon = &result.back();
             }
             polygon->push_back(XY(x, y));
         }
     }
 
-    if (polygon->size() == 0) {
-        result.pop_back();
-    }
+    _finalize_polygon(result);
 }
 
 template <class VertexSource>

src/_path_wrapper.cpp

@@ -8,16 +8,29 @@
 PyObject *convert_polygon_vector(std::vector<Polygon> &polygons)
 {
     PyObject *pyresult = PyList_New(polygons.size());
+    bool fix_endpoints;
 
     for (size_t i = 0; i < polygons.size(); ++i) {
         Polygon poly = polygons[i];
-        npy_intp dims[] = {(npy_intp)poly.size() + 1, 2 };
-        numpy::array_view<double, 2> subresult(dims);
+        npy_intp dims[2];
+        dims[1] = 2;
+
+        if (poly.front() != poly.back()) {
+            /* Make last point same as first, if not already */
+            dims[0] = (npy_intp)poly.size() + 1;
+            fix_endpoints = true;
+        } else {
+            dims[0] = (npy_intp)poly.size();
+            fix_endpoints = false;
+        }
 
-        /* Make last point same as first. */
+        numpy::array_view<double, 2> subresult(dims);
         memcpy(subresult.data(), &poly[0], sizeof(double) * poly.size() * 2);
-        subresult(poly.size(), 0) = poly[0].x;
-        subresult(poly.size(), 1) = poly[0].y;
+
+        if (fix_endpoints) {
+            subresult(poly.size(), 0) = poly.front().x;
+            subresult(poly.size(), 1) = poly.front().y;
+        }
 
         if (PyList_SetItem(pyresult, i, subresult.pyobj())) {
             Py_DECREF(pyresult);