linear_cmap

from numpy.random import standard_normal

from bokeh.plotting import figure, show
from bokeh.transform import linear_cmap
from bokeh.util.hex import hexbin

x = standard_normal(50000)
y = standard_normal(50000)

bins = hexbin(x, y, 0.1)

p = figure(tools="", match_aspect=True, background_fill_color='#440154')
p.grid.visible = False

p.hex_tile(q="q", r="r", size=0.1, line_color=None, source=bins,
           fill_color=linear_cmap('counts', 'Viridis256', 0, max(bins.counts)))

show(p)