interpolateHue function
Creates a hue interpolator for color hue values.
Implementation
Interpolator<double> interpolateHue(double a, double b) {
double d = b - a;
if (d > 180 || d < -180) {
d -= 360 * (d / 360).round();
}
return (double t) => (a + d * t) % 360;
}