Colormaps

colormap.py

import matplotlib.pyplot as plt
from matplotlib import cm
import numpy as np
from skimage import data
from skimage.color import rgb2gray
from colorspacious import cspace_converter

I = data.astronaut()
I = rgb2gray(I)
cmaps = ['gray', 'magma', 'jet', 'RdGy']
res = 3
plt.figure(figsize=(len(cmaps)*res, 2*res))
x = np.linspace(0, 1, 1000)

for i, cmap in enumerate(cmaps):
    rgb = cm.get_cmap(cmap)(x)[:, 0:3]
    lab = cspace_converter("sRGB1", "CAM02-UCS")(rgb)

    plt.subplot(2, len(cmaps), i+1)
    plt.scatter(x, lab[:, 0], 20, c=rgb)
    plt.ylim([0, 100])
    plt.title(cmap)
    plt.xlabel("Scalar Value")
    plt.ylabel("Lightness")

    plt.subplot(2, len(cmaps), i+1+len(cmaps))
    plt.imshow(I, cmap=cmap)
    plt.axis("off")

plt.tight_layout()
plt.savefig("colormaps.png", bbox_inches='tight')