BUG : fix optimized path transforms

tacaswell · tacaswell · commit 24bdc373bcb9 · 2015-01-17T14:08:13.000-05:00
Fixes #3998. The issue is that some transfroms sometimes returned masked arrays from `transform_non_affine` (ex Log10transform). The `Path` constructor fills masked arrays to full arrays with `np.nan`, but the `_fast_from_codes_and_verts` does not (as it assumes the verts have been fully validated on the way in). This adds the maskedarray -> np.nan filled array normalization into `transform_path_non_affine`.
diff --git a/lib/matplotlib/transforms.py b/lib/matplotlib/transforms.py
@@ -1300,7 +1300,7 @@ def transform(self, values):
 
         # Convert the result back to the shape of the input values.
         if ndim == 0:
-            assert not np.ma.is_masked(res)  # just to be on the safe side                                             
+            assert not np.ma.is_masked(res)  # just to be on the safe side
             return res[0, 0]
         if ndim == 1:
             return res.reshape(-1)
@@ -1412,6 +1412,8 @@ def transform_path_non_affine(self, path):
         ``transform_path_affine(transform_path_non_affine(values))``.
         """
         x = self.transform_non_affine(path.vertices)
+        if ma.isMaskedArray(x):
+            x = x.astype(np.float_).filled(np.nan)
         return Path._fast_from_codes_and_verts(x, path.codes,
                 {'interpolation_steps': path._interpolation_steps})
 
