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|
use std::{collections::HashMap, env::args};
use image::io::Reader as ImageReader;
use image::Rgb;
use rayon::prelude::*;
const MAX_COLORS: usize = 256;
const TOLERANCE: f32 = 0.025;
const RGB_TOLERANCE: f32 = 10.0 * TOLERANCE;
fn main() {
let filename = args().nth(1).unwrap();
let outname = args().nth(2).unwrap();
// The percent of RGB value difference a color has to surpass to be considered unique
let imageread = ImageReader::open(&filename).expect("Failed to open image!");
let mut image = imageread
.decode()
.expect("Failed to decode image!")
.into_rgb8();
let selected_colors = quantize(image.pixels());
// Max complexity is O(n * max_colors)
image.pixels_mut().par_bridge().for_each(|color| {
let mut min_difference = f32::MAX;
let mut min_difference_color = *color;
for selected_color in &selected_colors {
let difference = rgb_difference(color, selected_color);
if difference < min_difference {
min_difference = difference;
min_difference_color = *selected_color;
}
}
*color = min_difference_color
});
image.save(outname).expect("Failed to write out");
}
fn quantize<'a, T>(pixels: T) -> Vec<Rgb<u8>>
where
T: Iterator<Item = &'a Rgb<u8>>,
{
let mut colors: HashMap<Rgb<u8>, usize> = HashMap::new();
//count pixels
for pixel in pixels {
match colors.get_mut(pixel) {
None => {
colors.insert(*pixel, 1);
}
Some(n) => *n += 1,
}
}
let mut sorted: Vec<(Rgb<u8>, usize)> = colors.into_par_iter().collect();
sorted.sort_by(|(colour1, freq1), (colour2, freq2)| {
freq2
.cmp(freq1)
.then(colour2[0].cmp(&colour1[0]))
.then(colour2[1].cmp(&colour1[1]))
.then(colour2[2].cmp(&colour1[2]))
});
let mut selected_colors: Vec<Rgb<u8>> = Vec::with_capacity(MAX_COLORS);
for (key, _value) in sorted.iter() {
if selected_colors.len() >= MAX_COLORS {
break;
} else if selected_colors
.iter()
.all(|color| rgb_difference(key, color) > RGB_TOLERANCE)
{
selected_colors.push(*key);
}
}
selected_colors
}
#[allow(clippy::many_single_char_names)]
#[inline(always)]
fn rgb_difference(a: &Rgb<u8>, z: &Rgb<u8>) -> f32 {
let (a, b, c) = pixel_rgb_to_hsv(a);
let (d, e, f) = pixel_rgb_to_hsv(z);
(((c - f) * (c - f)) + ((a - d).abs() / 90.0) + (b - e).abs()) as f32
}
#[allow(clippy::float_cmp)]
fn pixel_rgb_to_hsv(a: &Rgb<u8>) -> (f32, f32, f32) {
let (r, g, b) = (
a.0[0] as f32 / 256.0,
a.0[1] as f32 / 256.0,
a.0[2] as f32 / 256.0,
);
let value = r.max(g.max(b));
let x_min = r.min(g.min(b));
let chroma = value - x_min;
let hue = if chroma == 0.0 {
0.0
} else if value == r {
60.0 * ((g - b) / chroma)
} else if value == g {
60.0 * (2.0 + (b - r) / chroma)
} else if value == b {
60.0 * (4.0 + (r - g) / chroma)
} else {
unreachable!()
};
let value_saturation = if value == 0.0 { 0.0 } else { chroma / value };
/* Rotate the color wheel counter clockwise to the negative location
| Keep the wheel in place and remove any full rotations
_____V____ _____V____
| | |*/
((hue + 360.0) % 360.0, value_saturation * 2.0, value * 2.0)
}
|
