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use crate::format::ser::{Ser, Sink, Source};
#[derive(Copy, Clone, Debug, Default, PartialEq)]
pub struct Pixel {
pub r: u8,
pub g: u8,
pub b: u8,
}
impl Ser for Pixel {
fn write(&self, sink: &mut impl std::io::Write) -> anyhow::Result<()> {
sink.put((self.r, self.g, self.b))
}
fn read(source: &mut impl std::io::Read) -> anyhow::Result<Self> {
let (r, g, b) = source.get()?;
Ok(Self { r, g, b })
}
}
impl Pixel {
pub const BLACK: Pixel = Pixel { r: 0, g: 0, b: 0 };
#[inline]
pub fn distance(a: Pixel, b: Pixel) -> usize {
let (rd, gd, bd) = (
a.r.abs_diff(b.r) as usize,
a.g.abs_diff(b.g) as usize,
a.b.abs_diff(b.b) as usize,
);
// fast_sqrt(rd * rd + gd * gd + bd * bd)
// SQRT[rd + gd + bd]
rd + gd + bd
}
#[inline]
pub fn average(a: Pixel, b: Pixel) -> Pixel {
Pixel {
r: ((a.r as u16 + b.r as u16) >> 1) as u8,
g: ((a.g as u16 + b.g as u16) >> 1) as u8,
b: ((a.b as u16 + b.b as u16) >> 1) as u8,
}
}
#[inline]
pub fn scale(&self, factor: f32) -> Pixel {
Pixel {
r: ((self.r as f32) * factor).clamp(0.0, 255.0) as u8,
g: ((self.g as f32) * factor).clamp(0.0, 255.0) as u8,
b: ((self.b as f32) * factor).clamp(0.0, 255.0) as u8,
}
}
}
pub const SQRT: [usize; 256 * 3] = gen_sqrt_lookup();
const fn gen_sqrt_lookup<const N: usize>() -> [usize; N] {
let mut arr = [0; N];
let mut i = 0;
while i < N {
arr[i] = sqrt(i as f32) as usize;
i += 1;
}
arr
}
const fn sqrt(x: f32) -> f32 {
let a = 1.0;
let a = (a + x / a) * 0.5;
let a = (a + x / a) * 0.5;
let a = (a + x / a) * 0.5;
a
}
pub fn fast_sqrt(x: usize) -> usize {
let a = 1;
let a = (a + x / (a + 1)) / 2;
let a = (a + x / (a + 1)) / 2;
// let a = (a + x / (a + 1)) / 2;
// let a = (a + x / (a + 1)) / 2;
a
}
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