Added zorder to clabel, test, whats new entry

pharshalp · pharshalp · commit 590c626a5f1a · 2020-01-26T15:56:10.000-05:00
diff --git a/doc/users/next_whats_new/2020-01-25-clabel_zorder.rst b/doc/users/next_whats_new/2020-01-25-clabel_zorder.rst
@@ -0,0 +1,4 @@
+Set zorder of contour labels
+----------------------------
+`~.axes.Axes.clabel` now accepts a ``zorder`` kwarg
+making it easier to set the ``zorder`` of contour labels.
diff --git a/lib/matplotlib/contour.py b/lib/matplotlib/contour.py
@@ -51,7 +51,7 @@ class ContourLabeler:
     def clabel(self, levels=None, *,
                fontsize=None, inline=True, inline_spacing=5, fmt='%1.3f',
                colors=None, use_clabeltext=False, manual=False,
-               rightside_up=True):
+               rightside_up=True, zorder=None):
         """
         Label a contour plot.
 
@@ -124,6 +124,11 @@ def clabel(self, levels=None, *,
             of texts during the drawing time, therefore this can be used if
             aspect of the axes changes.
 
+        zorder : float or None, optional
+            zorder of the contour labels.
+
+            If not specified, the default zorder of `.Text` class is used.
+
         Returns
         -------
         labels
@@ -144,6 +149,7 @@ def clabel(self, levels=None, *,
         # Detect if manual selection is desired and remove from argument list.
         self.labelManual = manual
         self.rightside_up = rightside_up
+        self._zorder = zorder
 
         if levels is None:
             levels = self.levels
@@ -397,7 +403,7 @@ def _get_label_text(self, x, y, rotation):
         dx, dy = self.ax.transData.inverted().transform((x, y))
         t = text.Text(dx, dy, rotation=rotation,
                       horizontalalignment='center',
-                      verticalalignment='center')
+                      verticalalignment='center', zorder=self._zorder)
         return t
 
     def _get_label_clabeltext(self, x, y, rotation):
@@ -411,7 +417,7 @@ def _get_label_clabeltext(self, x, y, rotation):
                                                   np.array([[x, y]]))
         t = ClabelText(dx, dy, rotation=drotation[0],
                        horizontalalignment='center',
-                       verticalalignment='center')
+                       verticalalignment='center', zorder=self._zorder)
 
         return t
 
diff --git a/lib/matplotlib/tests/test_contour.py b/lib/matplotlib/tests/test_contour.py
@@ -290,6 +290,22 @@ def test_circular_contour_warning():
     assert len(record) == 0
 
 
+@pytest.mark.parametrize("use_clabeltext", [True, False])
+def test_clabel_zorder(use_clabeltext):
+    x, y = np.meshgrid(np.arange(0, 10), np.arange(0, 10))
+    z = np.max(np.dstack([abs(x), abs(y)]), 2)
+
+    fig, (ax1, ax2) = plt.subplots(ncols=2)
+    cs1 = ax1.contour(x, y, z)
+    cs2 = ax2.contourf(x, y, z)
+    clabels1 = cs1.clabel(zorder=1234, use_clabeltext=use_clabeltext)
+    clabels2 = cs2.clabel(zorder=12345, use_clabeltext=use_clabeltext)
+    for clabel in clabels1:
+        assert clabel.get_zorder() == 1234
+    for clabel in clabels2:
+        assert clabel.get_zorder() == 12345
+
+
 @image_comparison(['contour_log_extension.png'],
                   remove_text=True, style='mpl20')
 def test_contourf_log_extension():
