sRGBの値をxy色度図にプロットする(Python)

import colour
import numpy as np
import matplotlib.pyplot as plt
colour.plotting.colour_style()

def deGumma(data):
 sdata = data / 255;
 if (sdata <= 0.04045):
 sdata = sdata / 12.92;
 else:
 sdata = ((sdata + 0.055) / 1.055)**2.4
 return sdata;

def scale_sRGB(sRGB):
 return np.array([deGumma(sRGB[0]), deGumma(sRGB[1]), deGumma(sRGB[2])])

def plot_sRGB_to_chromaticity_diagram_CIE1931(sRGB_list):
 # colour.plotting.plot_chromaticity_diagram_CIE1931(standalone=False)
 colour.plotting.plot_RGB_colourspaces_in_chromaticity_diagram_CIE1931(['sRGB'], standalone=False, diagram_opacity=0.5)

 for i, _ in enumerate(sRGB_list): 
 sRGB = scale_sRGB(sRGB_list[i])
 XYZ = colour.sRGB_to_XYZ(sRGB)
 xy = colour.XYZ_to_xy(XYZ)
 x, y = xy
 plt.plot(x, y, 'o-', color='white')

 # Annotating the plot.
 plt.annotate("sRGB"+str(i+1),
 xy=xy,
 xytext=(-50, 30),
 textcoords='offset points',
 arrowprops=dict(arrowstyle='->', connectionstyle='arc3, rad=-0.2'))

 # Displaying the plot.
 colour.plotting.render(
 standalone=True,
 limits=(-0.1, 0.9, -0.1, 0.9),
 x_tighten=True,
 y_tighten=True)

sRGB1 = [255, 0, 0]
sRGB2 = [0, 127, 0]
sRGB3 = [0, 0, 1]
sRGB4 = [1, 1, 0]
sRGB5 = [0, 1, 1]
sRGB6 = [1, 0, 1]
sRGB_list = [sRGB1, sRGB2, sRGB3, sRGB4, sRGB5, sRGB6]
plot_sRGB_to_chromaticity_diagram_CIE1931(sRGB_list)