Merge pull request #16469 from pharshalp/cbar_minorticks

jklymak · web-flow · commit 79fba06154b7 · 2020-02-11T10:08:32.000-08:00
FIX: colorbar minorticks when rcParams['x/ytick.minor.visible'] = True
diff --git a/lib/matplotlib/colorbar.py b/lib/matplotlib/colorbar.py
@@ -517,8 +517,12 @@ def _config_axis(self):
 
         if self.orientation == 'vertical':
             long_axis, short_axis = ax.yaxis, ax.xaxis
+            if mpl.rcParams['ytick.minor.visible']:
+                self.minorticks_on()
         else:
             long_axis, short_axis = ax.xaxis, ax.yaxis
+            if mpl.rcParams['xtick.minor.visible']:
+                self.minorticks_on()
 
         long_axis.set_label_position(self.ticklocation)
         long_axis.set_ticks_position(self.ticklocation)
diff --git a/lib/matplotlib/tests/test_colorbar.py b/lib/matplotlib/tests/test_colorbar.py
@@ -327,6 +327,34 @@ def test_colorbar_minorticks_on_off():
     np.testing.assert_equal(cbar.ax.yaxis.get_minorticklocs(), [])
 
 
+def test_cbar_minorticks_for_rc_xyminortickvisible():
+    """
+    issue gh-16468.
+
+    Making sure that minor ticks on the colorbar are turned on
+    (internally) using the cbar.minorticks_on() method when
+    rcParams['xtick.minor.visible'] = True (for horizontal cbar)
+    rcParams['ytick.minor.visible'] = True (for vertical cbar).
+    Using cbar.minorticks_on() ensures that the minor ticks
+    don't overflow into the extend regions of the colorbar.
+    """
+
+    plt.rcParams['ytick.minor.visible'] = True
+    plt.rcParams['xtick.minor.visible'] = True
+
+    vmin, vmax = 0.4, 2.6
+    fig, ax = plt.subplots()
+    im = ax.pcolormesh([[1, 2]], vmin=vmin, vmax=vmax)
+
+    cbar = fig.colorbar(im, extend='both', orientation='vertical')
+    assert cbar.ax.yaxis.get_minorticklocs()[0] >= vmin
+    assert cbar.ax.yaxis.get_minorticklocs()[-1] <= vmax
+
+    cbar = fig.colorbar(im, extend='both', orientation='horizontal')
+    assert cbar.ax.xaxis.get_minorticklocs()[0] >= vmin
+    assert cbar.ax.xaxis.get_minorticklocs()[-1] <= vmax
+
+
 def test_colorbar_autoticks():
     # Test new autotick modes. Needs to be classic because
     # non-classic doesn't go this route.
