rgba_rgb_add.rs

use std::io::{self, Write};

fn main() {
    let mut handle = io::BufWriter::new(io::stdout());
    let mut rgba = String::new();
    io::stdin().read_line(&mut rgba).unwrap();
    let rgba: Vec<&str> = rgba.trim().split(' ').collect();
    let rgba_v: Vec<u8> = rgba.iter().map(|x| x.parse().unwrap()).collect();
    let mut rgb = String::new();
    io::stdin().read_line(&mut rgb).unwrap();
    let rgb: Vec<&str> = rgb.trim().split(' ').collect();
    let rgb_v: Vec<u8> = rgb.iter().map(|x| x.parse().unwrap()).collect();
    let norm_rgba: Vec<f64> = rgba_v.iter().map(|x| *x as f64/255.0).collect();
    let norm_rgb: Vec<f64> = rgb_v.iter().map(|x| *x as f64/255.0).collect();
    let transparency = norm_rgba[3];
    let mut out_rgb: Vec<f64> = vec![0.; 3];
    for (index, (rgba, rgb)) in norm_rgba.iter().zip(norm_rgb.iter()).map(|(a, b)| (*a, *b)).enumerate() {
        write!(handle, "({index}, ({rgba}, {rgb})) ").ok();
        out_rgb[index] = (1. - transparency)*rgb + transparency*rgba;
    }
    let out_rgb: Vec<u8> = out_rgb.iter().map(|x| (x*255.).round() as u8).collect();
    write!(handle, "{out_rgb:?}").ok();
}