matplotlib · tacaswell · Jan 30, 2015 · Jan 29, 2015 · Jan 29, 2015 · Jan 29, 2015
diff --git a/lib/matplotlib/path.py b/lib/matplotlib/path.py
@@ -172,7 +172,7 @@ def _fast_from_codes_and_verts(cls, verts, codes, internals=None):
         Parameters
         ----------
         verts : numpy array
-        codes : numpy array (may not be None)
+        codes : numpy array
         internals : dict or None
             The attributes that the resulting path should have.
             Allowed keys are ``readonly``, ``should_simplify``,
@@ -182,6 +182,10 @@ def _fast_from_codes_and_verts(cls, verts, codes, internals=None):
         """
         internals = internals or {}
         pth = cls.__new__(cls)
+        if ma.isMaskedArray(verts):
+            verts = verts.astype(np.float_).filled(np.nan)
+        else:
+            verts = np.asarray(verts, np.float_)
         pth._vertices = verts
         pth._codes = codes
         pth._readonly = internals.pop('readonly', False)

diff --git a/lib/matplotlib/scale.py b/lib/matplotlib/scale.py
@@ -87,12 +87,12 @@ def get_transform(self):
 def _mask_non_positives(a):
     """
     Return a Numpy masked array where all non-positive values are
-    masked.  If there are no non-positive values, the original array
-    is returned.
+    replaced with NaNs.  If there are no non-positive values, the
+    original array is returned.
     """
     mask = a <= 0.0
     if mask.any():
-        return ma.MaskedArray(a, mask=mask)
+        return np.where(mask, np.nan, a)
     return a
 
 

diff --git a/lib/matplotlib/tests/baseline_images/test_path/semi_log_with_zero.png b/lib/matplotlib/tests/baseline_images/test_path/semi_log_with_zero.png
diff --git a/lib/matplotlib/tests/test_path.py b/lib/matplotlib/tests/test_path.py
@@ -72,6 +72,16 @@ def test_point_in_path_nan():
     assert not contains[0]
 
 
+@image_comparison(baseline_images=['semi_log_with_zero'], extensions=['png'])
+def test_log_transform_with_zero():
+    x = np.arange(-10, 10)
+    y = (1.0 - 1.0/(x**2+1))**20
+
+    fig, ax = plt.subplots()
+    ax.semilogy(x, y, "-o", lw=15)
+    ax.grid(True)
+
+
 if __name__ == '__main__':
     import nose
     nose.runmodule(argv=['-s', '--with-doctest'], exit=False)
diff --git a/src/_backend_agg.h b/src/_backend_agg.h
@@ -502,7 +502,8 @@ inline void RendererAgg::draw_markers(GCAgg &gc,
                                       agg::rgba color)
 {
     typedef agg::conv_transform<py::PathIterator> transformed_path_t;
-    typedef PathSnapper<transformed_path_t> snap_t;
+    typedef PathNanRemover<transformed_path_t> nan_removed_t;
+    typedef PathSnapper<nan_removed_t> snap_t;
     typedef agg::conv_curve<snap_t> curve_t;
     typedef agg::conv_stroke<curve_t> stroke_t;
     typedef agg::pixfmt_amask_adaptor<pixfmt, alpha_mask_type> pixfmt_amask_type;
@@ -515,14 +516,16 @@ inline void RendererAgg::draw_markers(GCAgg &gc,
     trans *= agg::trans_affine_translation(0.5, (double)height + 0.5);
 
     transformed_path_t marker_path_transformed(marker_path, marker_trans);
-    snap_t marker_path_snapped(marker_path_transformed,
+    nan_removed_t marker_path_nan_removed(marker_path_transformed, true, marker_path.has_curves());
+    snap_t marker_path_snapped(marker_path_nan_removed,
                                gc.snap_mode,
                                marker_path.total_vertices(),
                                points_to_pixels(gc.linewidth));
     curve_t marker_path_curve(marker_path_snapped);
 
     transformed_path_t path_transformed(path, trans);
-    snap_t path_snapped(path_transformed, SNAP_FALSE, path.total_vertices(), 0.0);
+    nan_removed_t path_nan_removed(path_transformed, false, false);
+    snap_t path_snapped(path_nan_removed, SNAP_FALSE, path.total_vertices(), 0.0);
     curve_t path_curve(path_snapped);
     path_curve.rewind(0);