Consolidate mpl version checks

lib/cartopy/mpl/__init__.py

@@ -3,3 +3,14 @@
 # This file is part of Cartopy and is released under the LGPL license.
 # See COPYING and COPYING.LESSER in the root of the repository for full
 # licensing details.
+
+import matplotlib
+import packaging.version
+
+
+_MPL_VERSION = packaging.version.parse(matplotlib.__version__)
+_MPL_34 = _MPL_VERSION.release[:2] >= (3, 4)
+_MPL_35 = _MPL_VERSION.release[:2] >= (3, 5)
+_MPL_38 = _MPL_VERSION.release[:2] >= (3, 8)
+
+assert _MPL_34, 'Cartopy is only supported with Matplotlib 3.4 or greater.'

lib/cartopy/mpl/contour.py

@@ -4,11 +4,11 @@
 # See COPYING and COPYING.LESSER in the root of the repository for full
 # licensing details.
 
-import matplotlib as mpl
 from matplotlib.contour import QuadContourSet
 import matplotlib.path as mpath
 import numpy as np
-import packaging
+
+from cartopy.mpl import _MPL_38
 
 
 class GeoContourSet(QuadContourSet):
@@ -21,7 +21,7 @@ class GeoContourSet(QuadContourSet):
     # fiddling with instance.__class__.
 
     def clabel(self, *args, **kwargs):
-        if packaging.version.parse(mpl.__version__).release[:2] < (3, 8):
+        if not _MPL_38:
             # nb: contour labelling does not work very well for filled
             # contours - it is recommended to only label line contours.
             # This is especially true when inline=True.

lib/cartopy/mpl/geoaxes.py

@@ -32,23 +32,19 @@
 import matplotlib.transforms as mtransforms
 import numpy as np
 import numpy.ma as ma
-import packaging
 import shapely.geometry as sgeom
 
 from cartopy import config
 import cartopy.crs as ccrs
 import cartopy.feature
+from cartopy.mpl import _MPL_38
 import cartopy.mpl.contour
 import cartopy.mpl.feature_artist as feature_artist
 import cartopy.mpl.geocollection
 import cartopy.mpl.patch as cpatch
 from cartopy.mpl.slippy_image_artist import SlippyImageArtist
 
 
-_MPL_VERSION = packaging.version.parse(mpl.__version__)
-assert _MPL_VERSION.release >= (3, 4), \
-    'Cartopy is only supported with Matplotlib 3.4 or greater.'
-
 # A nested mapping from path, source CRS, and target projection to the
 # resulting transformed paths:
 #     {path: {(source_crs, target_projection): list_of_paths}}
@@ -1604,7 +1600,7 @@ def contour(self, *args, **kwargs):
         result = super().contour(*args, **kwargs)
 
         # We need to compute the dataLim correctly for contours.
-        if _MPL_VERSION.release[:2] < (3, 8):
+        if not _MPL_38:
             bboxes = [col.get_datalim(self.transData)
                       for col in result.collections
                       if col.get_paths()]
@@ -1655,7 +1651,7 @@ def contourf(self, *args, **kwargs):
         result = super().contourf(*args, **kwargs)
 
         # We need to compute the dataLim correctly for contours.
-        if _MPL_VERSION.release[:2] < (3, 8):
+        if not _MPL_38:
             bboxes = [col.get_datalim(self.transData)
                       for col in result.collections
                       if col.get_paths()]
@@ -1952,7 +1948,7 @@ def _wrap_quadmesh(self, collection, **kwargs):
         # masked, so this will only draw a limited subset of
         # polygons that were actually wrapped.
 
-        if _MPL_VERSION.release[:2] < (3, 8):
+        if not _MPL_38:
             # We will add the original data mask in later to
             # make sure that set_array can work in future
             # calls on the proper sized array inputs.

lib/cartopy/mpl/geocollection.py

@@ -3,14 +3,11 @@
 # This file is part of Cartopy and is released under the LGPL license.
 # See COPYING and COPYING.LESSER in the root of the repository for full
 # licensing details.
-import matplotlib as mpl
 from matplotlib.collections import QuadMesh
 import numpy as np
 import numpy.ma as ma
-import packaging
 
-
-_MPL_VERSION = packaging.version.parse(mpl.__version__)
+from cartopy.mpl import _MPL_38
 
 
 def _split_wrapped_mesh_data(C, mask):
@@ -24,7 +21,7 @@ def _split_wrapped_mesh_data(C, mask):
     C_mask = getattr(C, 'mask', None)
     if C.ndim == 3:
         # RGB(A) array.
-        if _MPL_VERSION.release < (3, 8):
+        if not _MPL_38:
             raise ValueError("GeoQuadMesh wrapping for RGB(A) requires "
                              "Matplotlib v3.8 or later")
 
@@ -58,7 +55,7 @@ def get_array(self):
         if hasattr(self, '_wrapped_mask'):
             pcolor_data = self._wrapped_collection_fix.get_array()
             mask = self._wrapped_mask
-            if _MPL_VERSION.release[:2] < (3, 8):
+            if not _MPL_38:
                 A[mask] = pcolor_data
             else:
                 if A.ndim == 3:  # RGB(A) data.  Need to broadcast mask.
@@ -72,7 +69,7 @@ def get_array(self):
 
     def set_array(self, A):
         # Check the shape is appropriate up front.
-        if _MPL_VERSION.release[:2] < (3, 8):
+        if not _MPL_38:
             # Need to figure out existing shape from the coordinates.
             height, width = self._coordinates.shape[0:-1]
             if self._shading == 'flat':
@@ -102,7 +99,7 @@ def set_array(self, A):
             # Update the pcolor data with the wrapped masked data
             A, pcolor_data, _ = _split_wrapped_mesh_data(A, self._wrapped_mask)
 
-            if _MPL_VERSION.release[:2] < (3, 8):
+            if not _MPL_38:
                 self._wrapped_collection_fix.set_array(
                     pcolor_data[self._wrapped_mask].ravel())
             else:

lib/cartopy/tests/mpl/__init__.py

@@ -7,10 +7,6 @@
 import matplotlib as mpl
 import matplotlib.patches as mpatches
 import matplotlib.pyplot as plt
-import packaging.version
-
-
-MPL_VERSION = packaging.version.parse(mpl.__version__)
 
 
 def show(projection, geometry):

lib/cartopy/tests/mpl/test_caching.py

@@ -19,10 +19,10 @@
 import cartopy.crs as ccrs
 from cartopy.io.ogc_clients import _OWSLIB_AVAILABLE, WMTSRasterSource
 import cartopy.io.shapereader
+from cartopy.mpl import _MPL_38
 from cartopy.mpl.feature_artist import FeatureArtist
 import cartopy.mpl.geoaxes as cgeoaxes
 import cartopy.mpl.patch
-from cartopy.tests.mpl import MPL_VERSION
 
 
 def sample_data(shape=(73, 145)):
@@ -121,7 +121,7 @@ def test_contourf_transform_path_counting():
     with mock.patch('cartopy.mpl.patch.path_to_geos') as path_to_geos_counter:
         x, y, z = sample_data((30, 60))
         cs = ax.contourf(x, y, z, 5, transform=ccrs.PlateCarree())
-        if MPL_VERSION.release[:2] < (3, 8):
+        if not _MPL_38:
             n_geom = sum(len(c.get_paths()) for c in cs.collections)
         else:
             n_geom = len(cs.get_paths())

lib/cartopy/tests/mpl/test_crs.py

@@ -8,14 +8,12 @@
 import pytest
 
 import cartopy.crs as ccrs
-from cartopy.tests.mpl import MPL_VERSION
+from cartopy.mpl import _MPL_35
 
 
 @pytest.mark.natural_earth
-@pytest.mark.mpl_image_compare(filename="igh_land.png",
-                               tolerance=(3.6
-                                          if MPL_VERSION.release[:2] < (3, 5)
-                                          else 0.5))
+@pytest.mark.mpl_image_compare(
+    filename="igh_land.png", tolerance=0.5 if _MPL_35 else 3.6)
 def test_igh_land():
     crs = ccrs.InterruptedGoodeHomolosine(emphasis="land")
     ax = plt.axes(projection=crs)
@@ -26,9 +24,7 @@ def test_igh_land():
 
 @pytest.mark.natural_earth
 @pytest.mark.mpl_image_compare(filename="igh_ocean.png",
-                               tolerance=(4.5
-                                          if MPL_VERSION.release[:2] < (3, 5)
-                                          else 0.5))
+                               tolerance=0.5 if _MPL_35 else 4.5)
 def test_igh_ocean():
     crs = ccrs.InterruptedGoodeHomolosine(
         central_longitude=-160, emphasis="ocean"

lib/cartopy/tests/mpl/test_examples.py

@@ -8,7 +8,7 @@
 import pytest
 
 import cartopy.crs as ccrs
-from cartopy.tests.mpl import MPL_VERSION
+from cartopy.mpl import _MPL_38
 
 
 @pytest.mark.natural_earth
@@ -33,8 +33,7 @@ def test_global_map():
 
 @pytest.mark.natural_earth
 @pytest.mark.mpl_image_compare(
-    filename='contour_label.png',
-    tolerance=3.9 if MPL_VERSION.release[:2] >= (3, 8) else 0.5)
+    filename='contour_label.png', tolerance=3.9 if _MPL_38 else 0.5)
 def test_contour_label():
     from cartopy.tests.mpl.test_caching import sample_data
     fig = plt.figure()

lib/cartopy/tests/mpl/test_mpl_integration.py

@@ -12,7 +12,7 @@
 import pytest
 
 import cartopy.crs as ccrs
-from cartopy.tests.mpl import MPL_VERSION
+from cartopy.mpl import _MPL_35, _MPL_38
 
 
 @pytest.mark.natural_earth
@@ -197,8 +197,7 @@ def test_simple_global():
     ),
 ])
 @pytest.mark.mpl_image_compare(
-    tolerance=0.97 if MPL_VERSION.release[:2] < (3, 5) else 0.5,
-    style='mpl20')
+    tolerance=0.5 if _MPL_35 else 0.97, style='mpl20')
 def test_global_map(proj):
     if isinstance(proj, tuple):
         proj, kwargs = proj
@@ -241,8 +240,7 @@ def test_cursor_values():
                      r.encode('ascii', 'ignore'))
 
 
-SKIP_PRE_MPL38 = pytest.mark.skipif(
-    MPL_VERSION.release[:2] < (3, 8), reason='mpl < 3.8')
+SKIP_PRE_MPL38 = pytest.mark.skipif(not _MPL_38, reason='mpl < 3.8')
 PARAMETRIZE_PCOLORMESH_WRAP = pytest.mark.parametrize(
     'mesh_data_kind',
     [
@@ -357,7 +355,7 @@ def test_pcolormesh_get_array_with_mask(mesh_data_kind):
     result = c.get_array()
 
     expected = data2
-    if MPL_VERSION.release[:2] < (3, 8):
+    if not _MPL_38:
         expected = expected.ravel()
 
     np.testing.assert_array_equal(np.ma.getmask(result), np.isnan(expected))
@@ -521,7 +519,7 @@ def test_pcolormesh_set_array_nowrap():
     assert not hasattr(mesh, '_wrapped_collection_fix')
 
     expected = data
-    if MPL_VERSION.release[:2] < (3, 8):
+    if not _MPL_38:
         expected = expected.ravel()
     np.testing.assert_array_equal(mesh.get_array(), expected)
 
@@ -681,7 +679,7 @@ def test_pcolormesh_nan_wrap():
     ax = plt.axes(projection=ccrs.PlateCarree())
     mesh = ax.pcolormesh(xs, ys, data)
     pcolor = getattr(mesh, "_wrapped_collection_fix")
-    if MPL_VERSION.release[:2] < (3, 8):
+    if not _MPL_38:
         assert len(pcolor.get_paths()) == 2
     else:
         assert not pcolor.get_paths()
@@ -961,7 +959,7 @@ def test_barbs_1d_transformed():
 @pytest.mark.natural_earth
 @pytest.mark.mpl_image_compare(
     filename='streamplot.png', style='mpl20',
-    tolerance=9.77 if MPL_VERSION.release[:2] < (3, 5) else 0.5)
+    tolerance=0.5 if _MPL_35 else 9.77)
 def test_streamplot():
     x = np.arange(-60, 42.5, 2.5)
     y = np.arange(30, 72.5, 2.5)