Fix get_tick_params

- show values for x axis too
- fix nonfunctional test
- move axis tests from test_axes.py to test_axis.py
- make note in get_tick_params docstring more precise
- add GridOn to set_tick_params as it's always returned by
  get_tick_params, so it would be illogical if you couldn't
  set the paramter in the setter

Author: StefRe

doc/api/next_api_changes/behavior/27408-SR.rst

@@ -0,0 +1,8 @@
+Classes derived from Axis must implement get_tick_params
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Tick parameter translation depends on the concrete axis (x or y), so any
+axis class derived from `~matplotlib.axis.Axis` must implement
+`~matplotlib.axis.Axis.get_tick_params`. This is not necessary if the new axis
+class is derived from `.XAxis` or `.YAxis` (as for instance the Axis classes
+of `mpl_toolkits.mplot3d`).

lib/matplotlib/axes/_base.py

@@ -3394,6 +3394,8 @@ def tick_params(self, axis='both', **kwargs):
             Width of gridlines in points.
         grid_linestyle : str
             Any valid `.Line2D` line style spec.
+        gridOn : bool
+            Whether to draw the grid lines.
 
         Examples
         --------

lib/matplotlib/axis.py

@@ -931,8 +931,7 @@ def set_tick_params(self, which='major', reset=False, **kwargs):
         """
         Set appearance parameters for ticks, ticklabels, and gridlines.
 
-        For documentation of keyword arguments, see
-        :meth:`matplotlib.axes.Axes.tick_params`.
+        For documentation of keyword arguments, see `.Axes.tick_params`.
 
         See Also
         --------
@@ -976,6 +975,16 @@ def get_tick_params(self, which='major'):
         """
         Get appearance parameters for ticks, ticklabels, and gridlines.
 
+        .. note::
+            This method only returns the values of the parameters *bottom*, *top*,
+            *labelbottom*, *labeltop* or *left*, *right*, *labelleft*, *labelright*,
+            respectively, and *girdOn* as well as all additional parameters that were
+            set with `.Axis.set_tick_params` or methods that use it internally, such
+            as `.Axes.tick_params`. The returned parameters may differ from the values
+            of the current elements if they have been set by any other means (e.g.
+            via set_* methods for individual tick objects, `.pyplot.xticks`/
+            `.pyplot.yticks` or `.rcParams`).
+
         .. versionadded:: 3.7
 
         Parameters
@@ -988,13 +997,6 @@ def get_tick_params(self, which='major'):
         dict
             Properties for styling tick elements added to the axis.
 
-        Notes
-        -----
-        This method returns the appearance parameters for styling *new*
-        elements added to this axis and may be different from the values
-        on current elements if they were modified directly by the user
-        (e.g., via ``set_*`` methods on individual tick objects).
-
         Examples
         --------
         ::
@@ -1019,15 +1021,10 @@ def get_tick_params(self, which='major'):
 
 
         """
-        _api.check_in_list(['major', 'minor'], which=which)
-        if which == 'major':
-            return self._translate_tick_params(
-                self._major_tick_kw, reverse=True
-            )
-        return self._translate_tick_params(self._minor_tick_kw, reverse=True)
+        raise NotImplementedError('Derived must override')
 
     @staticmethod
-    def _translate_tick_params(kw, reverse=False):
+    def _translate_tick_params(kw, reverse=False, reverse_exclude=[]):
         """
         Translate the kwargs supported by `.Axis.set_tick_params` to kwargs
         supported by `.Tick._apply_params`.
@@ -1036,11 +1033,22 @@ def _translate_tick_params(kw, reverse=False):
         to the generic tick1, tick2 logic of the axis. Additionally, there
         are some other name translations.
 
-        Returns a new dict of translated kwargs.
+        Parameters
+        ----------
+        kw
+            kwargs dict to translate.
+        reverse
+            whether to translate from set_tick_params kwargs to
+            _apply_params kwargs or back.
+        reverse_exclude
+            list of keys to be removed from the keymap before reverse
+            translating. This is necessary because there are multiple keys
+            with the same value in keymap, depending on the axis.
 
-        Note: Use reverse=True to translate from those supported by
-        `.Tick._apply_params` back to those supported by
-        `.Axis.set_tick_params`.
+        Returns
+        -------
+        dict
+            new dict of translated kwargs
         """
         kw_ = {**kw}
 
@@ -1069,6 +1077,8 @@ def _translate_tick_params(kw, reverse=False):
             'labeltop': 'label2On',
         }
         if reverse:
+            for key in reverse_exclude:
+                del keymap[key]
             kwtrans = {
                 oldkey: kw_.pop(newkey)
                 for oldkey, newkey in keymap.items() if newkey in kw_
@@ -2518,6 +2528,15 @@ def get_tick_space(self):
         else:
             return 2**31 - 1
 
+    def get_tick_params(self, which='major'):
+        # docstring inherited
+        _api.check_in_list(['major', 'minor'], which=which)
+        return self._translate_tick_params(
+            getattr(self, f'_{which}_tick_kw'),
+            reverse=True,
+            reverse_exclude=['left', 'right', 'labelleft', 'labelright'],
+        )
+
 
 class YAxis(Axis):
     __name__ = 'yaxis'
@@ -2759,3 +2778,12 @@ def get_tick_space(self):
             return int(np.floor(length / size))
         else:
             return 2**31 - 1
+
+    def get_tick_params(self, which='major'):
+        # docstring inherited
+        _api.check_in_list(['major', 'minor'], which=which)
+        return self._translate_tick_params(
+            getattr(self, f'_{which}_tick_kw'),
+            reverse=True,
+            reverse_exclude=['bottom', 'top', 'labelbottom', 'labeltop'],
+        )

lib/matplotlib/tests/test_axes.py

@@ -6777,46 +6777,6 @@ def test_pandas_bar_align_center(pd):
     fig.canvas.draw()
 
 
-def test_axis_get_tick_params():
-    axis = plt.subplot().yaxis
-    initial_major_style_translated = {**axis.get_tick_params(which='major')}
-    initial_minor_style_translated = {**axis.get_tick_params(which='minor')}
-
-    translated_major_kw = axis._translate_tick_params(
-        axis._major_tick_kw, reverse=True
-    )
-    translated_minor_kw = axis._translate_tick_params(
-        axis._minor_tick_kw, reverse=True
-    )
-
-    assert translated_major_kw == initial_major_style_translated
-    assert translated_minor_kw == initial_minor_style_translated
-    axis.set_tick_params(labelsize=30, labelcolor='red',
-                         direction='out', which='both')
-
-    new_major_style_translated = {**axis.get_tick_params(which='major')}
-    new_minor_style_translated = {**axis.get_tick_params(which='minor')}
-    new_major_style = axis._translate_tick_params(new_major_style_translated)
-    new_minor_style = axis._translate_tick_params(new_minor_style_translated)
-    assert initial_major_style_translated != new_major_style_translated
-    assert axis._major_tick_kw == new_major_style
-    assert initial_minor_style_translated != new_minor_style_translated
-    assert axis._minor_tick_kw == new_minor_style
-
-
-def test_axis_set_tick_params_labelsize_labelcolor():
-    # Tests fix for issue 4346
-    axis_1 = plt.subplot()
-    axis_1.yaxis.set_tick_params(labelsize=30, labelcolor='red',
-                                 direction='out')
-
-    # Expected values after setting the ticks
-    assert axis_1.yaxis.majorTicks[0]._size == 4.0
-    assert axis_1.yaxis.majorTicks[0].tick1line.get_color() == 'k'
-    assert axis_1.yaxis.majorTicks[0].label1.get_size() == 30.0
-    assert axis_1.yaxis.majorTicks[0].label1.get_color() == 'red'
-
-
 def test_axes_tick_params_gridlines():
     # Now treating grid params like other Tick params
     ax = plt.subplot()

lib/matplotlib/tests/test_axis.py

@@ -1,4 +1,5 @@
 import numpy as np
+import pytest
 
 import matplotlib.pyplot as plt
 from matplotlib.axis import XTick
@@ -8,3 +9,54 @@ def test_tick_labelcolor_array():
     # Smoke test that we can instantiate a Tick with labelcolor as array.
     ax = plt.axes()
     XTick(ax, 0, labelcolor=np.array([1, 0, 0, 1]))
+
+
+@pytest.mark.parametrize("which", ["major", "minor"])
+@pytest.mark.parametrize(
+    "axis, expected_basic",
+    [
+        (
+            "x",
+            {
+                "bottom": True,
+                "top": True,  # tests use classic.mplstyle with top = True
+                "labelbottom": True,
+                "labeltop": False,
+                "gridOn": False,
+            },
+        ),
+        (
+            "y",
+            {
+                "left": True,
+                "right": True,  # tests use classic.mplstyle with right = True
+                "labelleft": True,
+                "labelright": False,
+                "gridOn": False,
+            },
+        ),
+    ],
+    ids=["xaxis", "yaxis"],
+)
+def test_axis_get_tick_params(axis, expected_basic, which):
+    axis = getattr(plt.subplot(), axis + "axis")
+    additional_kw = {"labelsize": 42}
+
+    axis.set_tick_params(which=which, **additional_kw)
+    expected = {**expected_basic, **additional_kw}
+    assert expected == axis.get_tick_params(which=which)
+    other = "minor" if which == "major" else "major"
+    assert expected_basic == axis.get_tick_params(which=other)
+
+
+def test_axis_set_tick_params_labelsize_labelcolor():
+    # Tests fix for issue 4346
+    axis_1 = plt.subplot()
+    axis_1.yaxis.set_tick_params(labelsize=30, labelcolor='red',
+                                 direction='out')
+
+    # Expected values after setting the ticks
+    assert axis_1.yaxis.majorTicks[0]._size == 4.0
+    assert axis_1.yaxis.majorTicks[0].tick1line.get_color() == "k"
+    assert axis_1.yaxis.majorTicks[0].label1.get_size() == 30.0
+    assert axis_1.yaxis.majorTicks[0].label1.get_color() == "red"