Merge pull request #4089 from neutrinoceros/hotfix_depr_colormap_api

BUG: avoid using deprecated matplotlib.cm API

doc/source/visualizing/colormaps/cmap_images.py

@@ -1,4 +1,4 @@
-import matplotlib.cm as cm
+import matplotlib as mpl
 
 import yt
 
@@ -8,7 +8,7 @@
 # Create projections using each colormap available.
 p = yt.ProjectionPlot(ds, "z", "density", weight_field="density", width=0.4)
 
-for cmap in cm.datad:
+for cmap in mpl.colormaps:
     if cmap.startswith("idl"):
         continue
     p.set_cmap(field="density", cmap=cmap)

yt/visualization/color_maps.py

@@ -1,9 +1,10 @@
 from copy import deepcopy
-from typing import Tuple, Union
+from typing import Optional, Tuple, Union
 
 import cmyt  # noqa: F401
+import matplotlib as mpl
 import numpy as np
-from matplotlib import cm as mcm, colors as cc
+from matplotlib.colors import Colormap, LinearSegmentedColormap
 from packaging.version import Version
 
 from yt.funcs import get_brewer_cmap
@@ -12,6 +13,24 @@
 from . import _colormap_data as _cm
 from ._commons import MPL_VERSION
 
+
+# wrap matplotlib.cm API, use non-deprecated API when available
+def _get_cmap(name: str) -> Colormap:
+    if MPL_VERSION >= Version("3.5"):
+        return mpl.colormaps[name]
+    else:
+        # deprecated API
+        return mpl.cm.get_cmap(name)
+
+
+def _register_cmap(cmap: Colormap, *, name: Optional[str] = None) -> None:
+    if MPL_VERSION >= Version("3.5"):
+        mpl.colormaps.register(cmap, name=name)
+    else:
+        # deprecated API
+        mpl.cm.register_cmap(name=name, cmap=cmap)
+
+
 yt_colormaps = {}
 
 
@@ -20,8 +39,8 @@ def add_colormap(name, cdict):
     Adds a colormap to the colormaps available in yt for this session
     """
     # Note: this function modifies the global variable 'yt_colormaps'
-    yt_colormaps[name] = cc.LinearSegmentedColormap(name, cdict, 256)
-    mcm.register_cmap(name, yt_colormaps[name])
+    yt_colormaps[name] = LinearSegmentedColormap(name, cdict, 256)
+    _register_cmap(yt_colormaps[name], name=name)
 
 
 # YTEP-0040 backward compatibility layer
@@ -51,13 +70,13 @@ def register_yt_colormaps_from_cmyt():
 
     for hist_name, alias in _HISTORICAL_ALIASES.items():
         if MPL_VERSION >= Version("3.4.0"):
-            cmap = mcm.get_cmap(alias).copy()
+            cmap = _get_cmap(alias).copy()
         else:
-            cmap = deepcopy(mcm.get_cmap(alias))
+            cmap = deepcopy(_get_cmap(alias))
         cmap.name = hist_name
         try:
-            mcm.register_cmap(cmap=cmap)
-            mcm.register_cmap(cmap=mcm.get_cmap(hist_name).reversed())
+            _register_cmap(cmap=cmap)
+            _register_cmap(cmap=_get_cmap(hist_name).reversed())
         except ValueError:
             # Matplotlib 3.4.0 hard-forbids name collisions, but more recent versions
             # will emit a warning instead, so we emulate this behaviour regardless.
@@ -95,7 +114,7 @@ def get_colormap_lut(cmap_id: Union[Tuple[str, str], str]):
     if isinstance(cmap_id, tuple) and len(cmap_id) == 2:
         cmap = get_brewer_cmap(cmap_id)
     elif isinstance(cmap_id, str):
-        cmap = mcm.get_cmap(cmap_id)
+        cmap = _get_cmap(cmap_id)
     else:
         raise TypeError(
             "Expected a string or a 2-tuple of strings as a colormap id. "
@@ -182,7 +201,7 @@ def show_colormaps(subset="all", filename=None):
     for i, m in enumerate(maps):
         plt.subplot(1, l, i + 1)
         plt.axis("off")
-        plt.imshow(a, aspect="auto", cmap=mcm.get_cmap(m), origin="lower")
+        plt.imshow(a, aspect="auto", cmap=_get_cmap(m), origin="lower")
         plt.title(m, rotation=90, fontsize=10, verticalalignment="bottom")
     if filename is not None:
         plt.savefig(filename, dpi=100, facecolor="gray")

yt/visualization/eps_writer.py

@@ -2,7 +2,7 @@
 
 import numpy as np
 import pyx
-from matplotlib import cm, pyplot as plt
+from matplotlib import pyplot as plt
 
 from yt.config import ytcfg
 from yt.units.unit_object import Unit  # type: ignore
@@ -744,7 +744,7 @@ def colorbar(
 
         # Convert the colormap into a string
         x = np.linspace(1, 0, 256)
-        cm_string = cm.get_cmap(name)(x, bytes=True)[:, 0:3].tobytes()
+        cm_string = plt.get_cmap(name)(x, bytes=True)[:, 0:3].tobytes()
 
         cmap_im = pyx.bitmap.image(imsize[0], imsize[1], "RGB", cm_string)
         if orientation == "top" or orientation == "bottom":

yt/visualization/plot_container.py

@@ -9,7 +9,6 @@
 from typing import Any, Dict, List, Optional, Tuple, Union
 
 import numpy as np
-from matplotlib.cm import get_cmap
 from matplotlib.font_manager import FontProperties
 from more_itertools.more import always_iterable
 
@@ -916,9 +915,11 @@ def set_background_color(self, field, color=None):
 
         """
         if color is None:
+            from yt.visualization.color_maps import _get_cmap
+
             cmap = self._colormap_config[field]
             if isinstance(cmap, str):
-                cmap = get_cmap(cmap)
+                cmap = _get_cmap(cmap)
             color = cmap(0)
         self._background_color[field] = color
         return self

yt/visualization/tests/test_splat.py

@@ -8,6 +8,7 @@
 import yt
 from yt.testing import assert_equal
 from yt.utilities.lib.api import add_rgba_points_to_image  # type: ignore
+from yt.visualization.color_maps import _get_cmap
 
 
 def setup():
@@ -30,7 +31,7 @@ def test_splat():
     xs = prng.random_sample(Np)
     ys = prng.random_sample(Np)
 
-    cbx = yt.visualization.color_maps.mcm.RdBu
+    cbx = _get_cmap("RdBu")
     cs = cbx(prng.random_sample(Np))
     add_rgba_points_to_image(image, xs, ys, cs)
 

yt/visualization/volume_rendering/image_handling.py

@@ -76,9 +76,10 @@ def plot_channel(
     specified.
     """
     from matplotlib import pyplot as plt
-    from matplotlib.cm import get_cmap
     from matplotlib.colors import LogNorm
 
+    from yt.visualization.color_maps import _get_cmap
+
     Nvec = image.shape[0]
     image[np.isnan(image)] = 0.0
     ma = image[image > 0.0].max()
@@ -94,7 +95,7 @@ def plot_channel(
     fig.subplots_adjust(
         left=0.0, right=1.0, bottom=0.0, top=1.0, wspace=0.0, hspace=0.0
     )
-    mycm = get_cmap(cmap)
+    mycm = _get_cmap(cmap)
     if log:
         ax.imshow(image, cmap=mycm, norm=mynorm, interpolation="nearest")
     else:

yt/visualization/volume_rendering/transfer_functions.py

@@ -1,5 +1,4 @@
 import numpy as np
-from matplotlib.cm import get_cmap
 from more_itertools import always_iterable
 
 from yt.funcs import mylog
@@ -728,12 +727,14 @@ def sample_colormap(self, v, w, alpha=None, colormap="gist_stern", col_bounds=No
         >>> tf = ColorTransferFunction((-10.0, -5.0))
         >>> tf.sample_colormap(-7.0, 0.01, colormap="cmyt.arbre")
         """
+        from yt.visualization.color_maps import _get_cmap
+
         v = np.float64(v)
         if col_bounds is None:
             rel = (v - self.x_bounds[0]) / (self.x_bounds[1] - self.x_bounds[0])
         else:
             rel = (v - col_bounds[0]) / (col_bounds[1] - col_bounds[0])
-        cmap = get_cmap(colormap)
+        cmap = _get_cmap(colormap)
         r, g, b, a = cmap(rel)
         if alpha is None:
             alpha = a
@@ -780,6 +781,8 @@ def map_to_colormap(
         ...     -6.0, -5.0, scale=10.0, colormap="cmyt.arbre", scale_func=linramp
         ... )
         """
+        from yt.visualization.color_maps import _get_cmap
+
         mi = np.float64(mi)
         ma = np.float64(ma)
         rel0 = int(
@@ -791,7 +794,7 @@ def map_to_colormap(
         rel0 = max(rel0, 0)
         rel1 = min(rel1, self.nbins - 1) + 1
         tomap = np.linspace(0.0, 1.0, num=rel1 - rel0)
-        cmap = get_cmap(colormap)
+        cmap = _get_cmap(colormap)
         cc = cmap(tomap)
         if scale_func is None:
             scale_mult = 1.0