def ipt_jch(start, amount, saturation, luminosity):
# Generate colors
k = 360/amount
colors = [(luminosity, saturation, start + i*k) for i in range(amount)]
# From lch to IPT
ans = ((l/100, c/100*cos(radians(h)), c/100*sin(radians(h)))
for l, c, h in colors)
# From IPT to XYZ1
ans = (convert_color(IPTColor(i, p, t), XYZColor, target_illuminant="d65")
for i, p, t in ans)
ipt_colors = (color.get_value_tuple() for color in ans)
# From JCh to XYZ1
ans = (cspace_convert(color, "JCh", "XYZ1") for color in colors)
jch_colors = (color.tolist() for color in ans)
# Compute average
ans = (((x1 + x2)/2, (y1 + y2)/2 , (z1 + z2)/2)
for (x1, y1, z1), (x2, y2, z2)
in zip(ipt_colors, jch_colors))
# From XYZ1 to sRGB1
ans = (cspace_convert(color, "XYZ1", "sRGB1") for color in ans)
ans = ((color.tolist() for color in ans))
ans = (sRGBColor(*color) for color in ans)
return to_hex_rgb(ans)
def XYZ_to_IPT(cobj, *args, **kwargs):
"""
Converts XYZ to IPT.
NOTE: XYZ values need to be adapted to 2 degree D65
Reference:
Fairchild, M. D. (2013). Color appearance models, 3rd Ed. (pp. 271-272).
John Wiley & Sons.
"""
if cobj.illuminant != "d65" or cobj.observer != "2":
raise ValueError("XYZColor for XYZ->IPT conversion needs to be D65 adapted.")
xyz_values = numpy.array(cobj.get_value_tuple())
lms_values = numpy.dot(IPTColor.conversion_matrices["xyz_to_lms"], xyz_values)
lms_prime = numpy.sign(lms_values) * numpy.abs(lms_values) ** 0.43
ipt_values = numpy.dot(IPTColor.conversion_matrices["lms_to_ipt"], lms_prime)
return IPTColor(*ipt_values)
def ipt(l, c, h):
i = l/100
p = c/100*cos(radians(h))
t = c/100*sin(radians(h))
return convert_color(IPTColor(i, p, t), sRGBColor, target_illuminant="d65")
def setUp(self):
self.color = IPTColor(0.5, 0.5, 0.5)
def test_conversion_to_ipt(self):
self.color.set_illuminant('D65')
ipt = convert_color(self.color, IPTColor)
self.assertColorMatch(ipt, IPTColor(0.5063, -0.3183, -0.1160))