added dark-mode diverging colormaps

Author: martinosorb

doc/users/next_whats_new/diverging_colormaps.rst

@@ -0,0 +1,24 @@
+Dark-mode diverging colormaps
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Three diverging colormaps have been added: "berlin", "managua", and "vanimo".
+They are dark-mode diverging colormaps, with minimum lightness at the center,
+and maximum at the extremes. These are taken from F. Crameri's Scientific
+colour maps version 8.0.1 (DOI: https://doi.org/10.5281/zenodo.1243862).
+
+
+.. plot::
+    :include-source: true
+    :alt: Example figures using "imshow" with dark-mode diverging colormaps on positive and negative data. First panel: "berlin" (blue to red with a black center); second panel: "managua" (orange to cyan with a dark purple center); third panel: "vanimo" (pink to green with a black center).
+
+    import numpy as np
+    import matplotlib.pyplot as plt
+
+    vals = np.linspace(-5, 5, 100)
+    x, y = np.meshgrid(vals, vals)
+    img = np.sin(x*y)
+
+    _, ax = plt.subplots(1, 3)
+    ax[0].imshow(img, cmap=plt.cm.berlin)
+    ax[1].imshow(img, cmap=plt.cm.managua)
+    ax[2].imshow(img, cmap=plt.cm.vanimo)

galleries/examples/color/colormap_reference.py

@@ -29,7 +29,8 @@
             'hot', 'afmhot', 'gist_heat', 'copper']),
          ('Diverging', [
             'PiYG', 'PRGn', 'BrBG', 'PuOr', 'RdGy', 'RdBu',
-            'RdYlBu', 'RdYlGn', 'Spectral', 'coolwarm', 'bwr', 'seismic']),
+            'RdYlBu', 'RdYlGn', 'Spectral', 'coolwarm', 'bwr', 'seismic',
+            'berlin', 'managua', 'vanimo']),
          ('Cyclic', ['twilight', 'twilight_shifted', 'hsv']),
          ('Qualitative', [
             'Pastel1', 'Pastel2', 'Paired', 'Accent',

galleries/users_explain/colors/colormaps.py

@@ -175,10 +175,15 @@ def plot_color_gradients(category, cmap_list):
 # equal minimum :math:`L^*` values at opposite ends of the colormap. By these
 # measures, BrBG and RdBu are good options. coolwarm is a good option, but it
 # doesn't span a wide range of :math:`L^*` values (see grayscale section below).
+#
+# Berlin, Managua, and Vanimo are dark-mode diverging colormaps, with minimum
+# lightness at the center, and maximum at the extremes. These are taken from
+# F. Crameri's [scientific colour maps]_ version 8.0.1.
 
 plot_color_gradients('Diverging',
                      ['PiYG', 'PRGn', 'BrBG', 'PuOr', 'RdGy', 'RdBu', 'RdYlBu',
-                      'RdYlGn', 'Spectral', 'coolwarm', 'bwr', 'seismic'])
+                      'RdYlGn', 'Spectral', 'coolwarm', 'bwr', 'seismic',
+                      'berlin', 'managua', 'vanimo'])
 
 # %%
 # Cyclic
@@ -441,3 +446,4 @@ def plot_color_gradients(cmap_category, cmap_list):
 # .. [colorblindness] http://www.color-blindness.com/
 # .. [IBM] https://doi.org/10.1109/VISUAL.1995.480803
 # .. [turbo] https://ai.googleblog.com/2019/08/turbo-improved-rainbow-colormap-for.html
+# .. [scientific colour maps] https://doi.org/10.5281/zenodo.1243862