cmap_discretisation

pyhelpers.ops.cmap_discretisation(cmap, n_colours)

Create a discrete colour ramp.

See also [OPS-CD-1].

Parameters:

• cmap (matplotlib.colors.ListedColormap | matplotlib.colors.LinearSegmentedColormap | str) – a colormap instance, e.g. built-in colormaps that is available via matplotlib.colormaps.get_cmap

• n_colours (int) – number of colours

Returns:

a discrete colormap from (the continuous) cmap

Return type:

matplotlib.colors.LinearSegmentedColormap

Examples:

>>> from pyhelpers.ops import cmap_discretisation
>>> from pyhelpers.settings import mpl_preferences

>>> mpl_preferences(backend='TkAgg', font_name='Times New Roman')

>>> import matplotlib
>>> import matplotlib.pyplot as plt
>>> import numpy as np

>>> cm_accent = cmap_discretisation(cmap=matplotlib.colormaps['Accent'], n_colours=5)
>>> cm_accent.name
'Accent_5'
>>> cm_accent = cmap_discretisation(cmap='Accent', n_colours=5)
>>> cm_accent.name
'Accent_5'

>>> fig = plt.figure(figsize=(10, 2), constrained_layout=True)
>>> ax = fig.add_subplot()

>>> ax.imshow(np.resize(range(100), (5, 100)), cmap=cm_accent, interpolation='nearest')

>>> plt.axis('off')
>>> plt.show()

The exmaple is illustrated in Fig. 3:

Fig. 3 An example of discrete colour ramp, created by the function cmap_discretisation().

>>> plt.close()