Function to generate a set of colors as distinct as possible in VisPy

distinguishable_colors_example.py

# Ported from: http://www.mathworks.com/matlabcentral/fileexchange/29702-generate-maximally-perceptually-distinct-colors
import sys
import numpy as np
from vispy import scene
from vispy.color import ColorArray
from vispy.color.color_array import _rgb_to_lab


def distinguishable_colors(ncolors, bg=[0, 0, 0]):
    n_grid = 30
    x = np.linspace(0, 1, n_grid)
    R, G, B = np.meshgrid(x, x, x)

    rgb = np.column_stack((R.flatten(),
                           G.flatten(),
                           B.flatten())).astype(np.float32)
    lab = _rgb_to_lab(rgb)

    bglab = np.array(bg).astype(np.float32)
    bglab = _rgb_to_lab(bglab)

    mindist2 = np.full(rgb.shape[0], float('Inf'))
    for i in range(0, bglab.shape[0]):
        dX = lab - bglab[i, :]
        dist2 = np.sum(dX**2, axis=1)
        mindist2 = np.minimum(dist2, mindist2)

    colors = np.zeros((ncolors, 3))
    lastlab = bglab[-1, :]
    for i in range(0, ncolors):
        dX = lab - lastlab
        dist2 = np.sum(dX**2, axis=1)
        mindist2 = np.minimum(dist2, mindist2)
        index = mindist2.argmax()
        colors[i, :] = rgb[index, :]
        lastlab = lab[index, :]

    return ColorArray(color=colors[0:ncolors, :])


canvas = scene.SceneCanvas(keys='interactive', size=(800, 600), show=True)
view = canvas.central_widget.add_view()

npoints = 50
delta = 0.1
points = np.array([[i*delta, 0, 0] for i in range(1, npoints)]).astype(np.float32)
color = distinguishable_colors(npoints)
scene.visuals.Tube(points, color=color, parent=view.scene)

view.camera = scene.cameras.ArcballCamera(fov=60, parent=view.scene)
if __name__ == '__main__' and sys.flags.interactive == 0:
    canvas.app.run()