Deprecated _apply_theta_transforms=True

dstansby · dstansby · commit 9bed666452d1 · 2023-01-01T19:24:38.000Z
diff --git a/doc/api/next_api_changes/deprecations/24834-DS.rst b/doc/api/next_api_changes/deprecations/24834-DS.rst
@@ -0,0 +1,6 @@
+Applying theta transforms in ``PolarTransform``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Applying theta transforms in `~matplotlib.projections.polar.PolarTransform`
+is deprecated. This is currently the default behaviour, so to prevent
+a warning, manually pass ``_apply_theta_transforms=False``, and
+apply any theta shift before passing points to this transform.
diff --git a/lib/matplotlib/projections/polar.py b/lib/matplotlib/projections/polar.py
@@ -35,6 +35,17 @@ def __init__(self, axis=None, use_rmin=True,
         self._axis = axis
         self._use_rmin = use_rmin
         self._apply_theta_transforms = _apply_theta_transforms
+        if _apply_theta_transforms:
+            _api.warn_deprecated(
+                "3.7",
+                message=(
+                    "Passing `_apply_theta_transforms=True` (the default) "
+                    "is deprecated. Support for this will be removed in "
+                    "Matplotlib %(removal)s. To prevent this warning, "
+                    "set `_apply_theta_transforms=False`, and make sure to "
+                    "shift theta values before being passed to this transform."
+                )
+            )
 
     __str__ = mtransforms._make_str_method(
         "_axis",
diff --git a/lib/matplotlib/text.py b/lib/matplotlib/text.py
@@ -1508,7 +1508,7 @@ def _get_xy_transform(self, renderer, s):
             return self.axes.transData
         elif s == 'polar':
             from matplotlib.projections import PolarAxes
-            tr = PolarAxes.PolarTransform()
+            tr = PolarAxes.PolarTransform(_apply_theta_transforms=False)
             trans = tr + self.axes.transData
             return trans
 
diff --git a/lib/mpl_toolkits/axisartist/tests/test_floating_axes.py b/lib/mpl_toolkits/axisartist/tests/test_floating_axes.py
@@ -24,7 +24,7 @@ def test_curvelinear3():
     fig = plt.figure(figsize=(5, 5))
 
     tr = (mtransforms.Affine2D().scale(np.pi / 180, 1) +
-          mprojections.PolarAxes.PolarTransform())
+          mprojections.PolarAxes.PolarTransform(_apply_theta_transforms=False))
     grid_helper = GridHelperCurveLinear(
         tr,
         extremes=(0, 360, 10, 3),
@@ -73,7 +73,7 @@ def test_curvelinear4():
     fig = plt.figure(figsize=(5, 5))
 
     tr = (mtransforms.Affine2D().scale(np.pi / 180, 1) +
-          mprojections.PolarAxes.PolarTransform())
+          mprojections.PolarAxes.PolarTransform(_apply_theta_transforms=False))
     grid_helper = GridHelperCurveLinear(
         tr,
         extremes=(120, 30, 10, 0),
diff --git a/lib/mpl_toolkits/axisartist/tests/test_grid_helper_curvelinear.py b/lib/mpl_toolkits/axisartist/tests/test_grid_helper_curvelinear.py
@@ -84,7 +84,8 @@ def test_polar_box():
 
     # PolarAxes.PolarTransform takes radian. However, we want our coordinate
     # system in degree
-    tr = Affine2D().scale(np.pi / 180., 1.) + PolarAxes.PolarTransform()
+    tr = (Affine2D().scale(np.pi / 180., 1.) +
+          PolarAxes.PolarTransform(_apply_theta_transforms=False))
 
     # polar projection, which involves cycle, and also has limits in
     # its coordinates, needs a special method to find the extremes
@@ -146,7 +147,8 @@ def test_axis_direction():
 
     # PolarAxes.PolarTransform takes radian. However, we want our coordinate
     # system in degree
-    tr = Affine2D().scale(np.pi / 180., 1.) + PolarAxes.PolarTransform()
+    tr = (Affine2D().scale(np.pi / 180., 1.) +
+          PolarAxes.PolarTransform(_apply_theta_transforms=False))
 
     # polar projection, which involves cycle, and also has limits in
     # its coordinates, needs a special method to find the extremes
