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use num::Float;
use {Alpha, Rgb, Rgba, clamp, flt};
use pixel::RgbPixel;
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct GammaRgb<T: Float = f32> {
pub red: T,
pub green: T,
pub blue: T,
pub alpha: T,
pub gamma: T,
}
impl<T: Float> GammaRgb<T> {
pub fn new(red: T, green: T, blue: T, gamma: T) -> GammaRgb<T> {
GammaRgb::with_alpha(red, green, blue, T::one(), gamma)
}
pub fn with_alpha(red: T, green: T, blue: T, alpha: T, gamma: T) -> GammaRgb<T> {
GammaRgb {
red: red,
green: green,
blue: blue,
alpha: alpha,
gamma: gamma,
}
}
pub fn new_u8(red: u8, green: u8, blue: u8, gamma: T) -> GammaRgb<T> {
GammaRgb::with_alpha_u8(red, green, blue, 255, gamma)
}
pub fn with_alpha_u8(red: u8, green: u8, blue: u8, alpha: u8, gamma: T) -> GammaRgb<T> {
GammaRgb {
red: flt::<T,_>(red) / flt(255.0),
green: flt::<T,_>(green) / flt(255.0),
blue: flt::<T,_>(blue) / flt(255.0),
alpha: flt::<T,_>(alpha) / flt(255.0),
gamma: gamma,
}
}
pub fn from_pixel<P: RgbPixel<T>>(pixel: &P, gamma: T) -> GammaRgb<T> {
let (r, g, b, a) = pixel.to_rgba();
GammaRgb::with_alpha(r, g, b, a, gamma)
}
pub fn to_pixel<P: RgbPixel<T>>(&self) -> P {
P::from_rgba(
clamp(self.red, T::zero(), T::one()),
clamp(self.green, T::zero(), T::one()),
clamp(self.blue, T::zero(), T::one()),
clamp(self.alpha, T::zero(), T::one()),
)
}
pub fn from_linear<C: Into<Rgba<T>>>(color: C, gamma: T) -> GammaRgb<T> {
let rgb = color.into();
GammaRgb {
red: to_gamma(rgb.red, gamma),
green: to_gamma(rgb.green, gamma),
blue: to_gamma(rgb.blue, gamma),
alpha: rgb.alpha,
gamma: gamma,
}
}
pub fn to_linear(&self) -> Rgba<T> {
Alpha {
color: Rgb {
red: from_gamma(self.red, self.gamma),
green: from_gamma(self.green, self.gamma),
blue: from_gamma(self.blue, self.gamma),
},
alpha: self.alpha,
}
}
pub fn linear_to_pixel<C: Into<Rgba<T>>, P: RgbPixel<T>>(color: C, gamma: T) -> P {
GammaRgb::from_linear(color, gamma).to_pixel()
}
}
fn from_gamma<T: Float>(x: T, gamma: T) -> T {
x.powf(T::one() / gamma)
}
fn to_gamma<T: Float>(x: T, gamma: T) -> T {
x.powf(gamma)
}