Raise IgnoredKeywordWarning on unsupported kwargs of spy()

timhoffm · timhoffm · commit d884b2dcf87d · 2018-06-21T21:56:42.000+02:00
diff --git a/doc/api/next_api_changes/2018-06-02-TH.rst b/doc/api/next_api_changes/2018-06-02-TH.rst
@@ -0,0 +1,14 @@
+Changes to `matplotlib.axes.Axes.spy`
+-------------------------------------
+
+The method `matplotlib.axes.Axes.spy` now raises a `.IgnoredKeywordWarning`
+for the keyword arguments 'interpolation' and 'linestyle' instead of silently
+ignoring them.
+
+Furthermore, `matplotlib.axes.Axes.spy` spy does now allow for an 'extent'
+argument (was silently ignored so far).
+
+A bug with `spy(..., origin='lower') is fixed: So far this flipped the
+data but not the y-axis resulting in a mismatch between axes labels and
+actual data indices. Now, `origin='lower'` flips both the data and the y-axis
+labels.
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -35,7 +35,7 @@
 import matplotlib.tri as mtri
 from matplotlib.cbook import (
     mplDeprecation, warn_deprecated, STEP_LOOKUP_MAP, iterable,
-    safe_first_element)
+    safe_first_element, IgnoredKeywordWarning)
 from matplotlib.container import BarContainer, ErrorbarContainer, StemContainer
 from matplotlib.axes._base import _AxesBase, _process_plot_format
 
@@ -7397,10 +7397,13 @@ def spy(self, Z, precision=0, marker=None, markersize=None,
             if 'cmap' not in kwargs:
                 kwargs['cmap'] = mcolors.ListedColormap(['w', 'k'],
                                                         name='binary')
-            nr, nc = Z.shape
-            extent = [-0.5, nc - 0.5, nr - 0.5, -0.5]
+            if 'interpolation' in kwargs:
+                kwargs.pop('interpolation')
+                warnings.warn(
+                    '"interpolation" keyword argument will be ignored',
+                    IgnoredKeywordWarning)
             ret = self.imshow(mask, interpolation='nearest', aspect=aspect,
-                                extent=extent, origin=origin, **kwargs)
+                              origin=origin, **kwargs)
         else:
             if hasattr(Z, 'tocoo'):
                 c = Z.tocoo()
@@ -7419,6 +7422,11 @@ def spy(self, Z, precision=0, marker=None, markersize=None,
                 marker = 's'
             if markersize is None:
                 markersize = 10
+            if 'linestyle' in kwargs:
+                kwargs.pop('linestyle')
+                warnings.warn(
+                    '"interpolation" keyword argument will be ignored',
+                    IgnoredKeywordWarning)
             marks = mlines.Line2D(x, y, linestyle='None',
                          marker=marker, markersize=markersize, **kwargs)
             self.add_line(marks)
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -61,6 +61,17 @@ def test_spy():
     ax.spy(a)
 
 
+def test_spy_warn_ignored_kwargs():
+    fig, ax = plt.subplots()
+    for unsupported_kw in [{'interpolation': 'nearest'},
+                           {'marker': 'o', 'linestyle': 'solid'}]:
+        with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter("always")
+            ax.spy(np.eye(3, 3), **unsupported_kw)
+            assert len(w) == 1
+            assert issubclass(w[0].category, IgnoredKeywordWarning)
+
+
 @image_comparison(baseline_images=['matshow'],
                   extensions=['png'], style='mpl20')
 def test_matshow():
