30 lines
885 B
Python
30 lines
885 B
Python
from dataclasses import dataclass
|
|
|
|
@dataclass
|
|
class Color:
|
|
red: float
|
|
green: float
|
|
blue: float
|
|
alpha: float
|
|
|
|
def __mul__(self, o) -> "Color":
|
|
return Color(self.red * o, self.green * o,
|
|
self.blue * o, self.alpha * o)
|
|
|
|
def __truediv__(self, o) -> "Color":
|
|
return Color(self.red / o, self.green / o,
|
|
self.blue / o, self.alpha / o)
|
|
|
|
def __add__(self, o) -> "Color":
|
|
return Color(self.red + o.red, self.green + o.green,
|
|
self.blue + o.blue, self.alpha + o.alpha)
|
|
|
|
def composite1(C_fg: Color, a_fg: float, C_bg: Color):
|
|
return C_fg * a_fg + C_bg * (1.0 - a_fg)
|
|
|
|
def composite2(C_fg: Color, a_fg: float, C_bg: Color, a_bg: float = 1):
|
|
a_final = a_fg + a_bg * (1.0 - a_fg)
|
|
return (C_fg * a_fg + C_bg * a_bg * (1.0 - a_fg)) / a_final
|
|
|
|
C_bg = Color(0.0, 0.0, 0.0, 1.0)
|