The penguins dataset, drawn twice with semi-transparent markers. This is an interesting use-case to test blending, because several samples itself overlap, and by drawing the set twice with different colors, we realize even more interesting blending. Also note how this makes use of different ways to specify (css) colors. This example is a good reference to test WebGL blending.

from bokeh.plotting import figure, show
from bokeh.sampledata.penguins import data

colormap1 = {'Adelie': 'rgb(255, 0, 0)',
             'Chinstrap': 'rgb(0, 255, 0)',
             'Gentoo': 'rgb(0, 0, 255)'}
colors1 = [colormap1[x] for x in data['species']]

colormap2 = {'Adelie': '#0f0', 'Chinstrap': '#0f0', 'Gentoo': '#f00'}
colors2 = [colormap2[x] for x in data['species']]

p = figure(output_backend="webgl")

p.diamond(data["flipper_length_mm"], data["body_mass_g"],
          color=colors1, line_alpha=0.5, fill_alpha=0.2, size=25, legend_label='diamonds')["flipper_length_mm"], data["body_mass_g"],
         color=colors2, line_alpha=0.5, fill_alpha=0.2, size=10, legend_label='circles')