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