def shade(self, stroke):
it = stroke.stroke_vertices_begin()
func = MaterialF0D()
xn = 0.312713
yn = 0.329016
Yn = 1.0
un = 4. * xn / (-2. * xn + 12. * yn + 3.)
vn = 9. * yn / (-2. * xn + 12. * yn + 3.)
while not it.is_end:
mat = func(Interface0DIterator(it))
r = mat.diffuse[0]
g = mat.diffuse[1]
b = mat.diffuse[2]
X = 0.412453 * r + 0.35758 * g + 0.180423 * b
Y = 0.212671 * r + 0.71516 * g + 0.072169 * b
Z = 0.019334 * r + 0.119193 * g + 0.950227 * b
if (X, Y, Z) == (0, 0, 0):
X = 0.01
Y = 0.01
Z = 0.01
u = 4. * X / (X + 15. * Y + 3. * Z)
v = 9. * Y / (X + 15. * Y + 3. * Z)
L = 116. * pow((Y / Yn), (1. / 3.)) - 16
U = 13. * L * (u - un)
V = 13. * L * (v - vn)
if L > self._threshold:
L = L / 1.3
U = U + 10
else:
L = L + 2.5 * (100 - L) / 5.
U = U / 3.0
V = V / 3.0
u = U / (13. * L) + un
v = V / (13. * L) + vn
Y = Yn * pow(((L + 16.) / 116.), 3.)
X = -9.0 * Y * u / ((u - 4.0) * v - u * v)
Z = (9.0 * Y - 15.0 * v * Y - v * X) / (3.0 * v)
r = 3.240479 * X - 1.53715 * Y - 0.498535 * Z
g = -0.969256 * X + 1.875991 * Y + 0.041556 * Z
b = 0.055648 * X - 0.204043 * Y + 1.057311 * Z
r = max(0, r)
g = max(0, g)
b = max(0, b)
it.object.attribute.color = (r, g, b)
it.increment()
def __init__(self, threshold=50):
StrokeShader.__init__(self)
self._threshold = threshold
self._func = MaterialF0D()