Deprecate some Transform aliases in scale.py.

anntzer · anntzer · commit a46f5083213e · 2020-01-07T13:54:42.000+01:00
They are available as globals in the module.  More annoyingly, having
them duplicated prevents one from writing
```
`.LogTransform`
```
in the docs because sphinx doesn't know whether to resolve this to
`mpl.scale.LogTransform` or `mpl.scale.LogScale.LogTransform` (it
doesn't realize these are the same).
diff --git a/doc/api/next_api_changes/deprecations.rst b/doc/api/next_api_changes/deprecations.rst
@@ -124,3 +124,10 @@ The following parameters do not have any effect and are deprecated:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 This method is deprecated.  Use
 ``ax.dataLim.set(Bbox.union([ax.dataLim, bounds]))`` instead.
+
+``{,Symmetrical}LogScale.{,Inverted}LogTransform``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+``LogScale.LogTransform``, ``LogScale.InvertedLogTransform``,
+``SymmetricalScale.SymmetricalTransform`` and
+``SymmetricalScale.InvertedSymmetricalTransform`` are deprecated.  Directly
+access the transform classes from the :mod:`.scale` module.
diff --git a/lib/matplotlib/scale.py b/lib/matplotlib/scale.py
@@ -344,8 +344,16 @@ class LogScale(ScaleBase):
     InvertedLog2Transform = InvertedLog2Transform
     NaturalLogTransform = NaturalLogTransform
     InvertedNaturalLogTransform = InvertedNaturalLogTransform
-    LogTransform = LogTransform
-    InvertedLogTransform = InvertedLogTransform
+
+    @cbook.deprecated("3.3", alternative="scale.LogTransform")
+    @property
+    def LogTransform(self):
+        return LogTransform
+
+    @cbook.deprecated("3.3", alternative="scale.InvertedLogTransform")
+    @property
+    def InvertedLogTransform(self):
+        return InvertedLogTransform
 
     def __init__(self, axis, **kwargs):
         """
@@ -535,9 +543,17 @@ class SymmetricalLogScale(ScaleBase):
         the logarithmic range.
     """
     name = 'symlog'
-    # compatibility shim
-    SymmetricalLogTransform = SymmetricalLogTransform
-    InvertedSymmetricalLogTransform = InvertedSymmetricalLogTransform
+
+    @cbook.deprecated("3.3", alternative="scale.SymmetricalLogTransform")
+    @property
+    def SymmetricalLogTransform(self):
+        return SymmetricalLogTransform
+
+    @cbook.deprecated(
+        "3.3", alternative="scale.InvertedSymmetricalLogTransform")
+    @property
+    def InvertedSymmetricalLogTransform(self):
+        return InvertedSymmetricalLogTransform
 
     def __init__(self, axis, **kwargs):
         if axis.axis_name == 'x':
diff --git a/lib/matplotlib/tests/test_transforms.py b/lib/matplotlib/tests/test_transforms.py
@@ -3,11 +3,11 @@
                            assert_array_equal, assert_array_almost_equal)
 import pytest
 
+from matplotlib import scale
 import matplotlib.pyplot as plt
 import matplotlib.patches as mpatches
 import matplotlib.transforms as mtransforms
 from matplotlib.path import Path
-from matplotlib.scale import LogScale
 from matplotlib.testing.decorators import image_comparison
 
 
@@ -196,7 +196,7 @@ def test_clipping_of_log():
 
     # something like this happens in plotting logarithmic histograms
     trans = mtransforms.BlendedGenericTransform(
-        mtransforms.Affine2D(), LogScale.LogTransform(10, 'clip'))
+        mtransforms.Affine2D(), scale.LogTransform(10, 'clip'))
     tpath = trans.transform_path_non_affine(path)
     result = tpath.iter_segments(trans.get_affine(),
                                  clip=(0, 0, 100, 100),
