Code shared from the Rust Playground

playground.rs

use image::{ImageBuffer, Rgb};
use sha2::{Digest, Sha256};

const COLORS: [&str; 256] = [
    "#c4b9b8", "#879f84", "#a6814c", "#ff9966", "#aa1155", "#7a81ff", "#8e473b", "#f3dfb6",
    "#dfac4c", "#4b3621", "#feff32", "#a57c5b", "#52b4ca", "#fffc79", "#879877", "#bb1133",
    "#eee9d9", "#52b4d3", "#ffff81", "#4f4554", "#c68f65", "#d2e7ca", "#0000ff", "#2ee8bb",
    "#eebb88", "#eddd59", "#7f5f00", "#eeaa11", "#35fa00", "#ffefd6", "#bb11aa", "#dab4cc",
    "#fff0db", "#987d73", "#c4fff7", "#eae0c8", "#e2c779", "#ff4d00", "#334d41", "#f83800",
    "#ddedbd", "#ffdd44", "#efd7ab", "#66eeee", "#aa3333", "#006663", "#ffb75f", "#c6bb9c",
    "#685c53", "#fff1dc", "#313390", "#ff6f01", "#8f8ce7", "#cf0234", "#ff9966", "#5f5537",
    "#342931", "#f6eeed", "#fe019a", "#772299", "#ff6ec7", "#f2e6e1", "#ffb49b", "#252525",
    "#dcf1c7", "#674876", "#eeaa55", "#c7031e", "#7a2e4d", "#9f0000", "#eed683", "#e6dee6",
    "#fdd7e4", "#95859c", "#bfa58a", "#16141c", "#7b9a6d", "#cc6666", "#ddece0", "#e398af",
    "#004488", "#fea993", "#6d5698", "#ef1de7", "#ff028d", "#eae9e7", "#f6e2ea", "#b8b8f8",
    "#ccddcc", "#b06500", "#ecebe5", "#7fbb9e", "#88b5c4", "#93c572", "#dddd88", "#805b87",
    "#698890", "#ebe2cf", "#ee2222", "#c95a49", "#220011", "#f1ebc8", "#006400", "#553b39",
    "#ffa177", "#cbc5c6", "#738f5d", "#32575d", "#fed55d", "#a2bffe", "#98333a", "#d7e7d0",
    "#958b84", "#ee0000", "#3b2b2c", "#ff8656", "#f0fff0", "#44232f", "#faebd7", "#786e38",
    "#080813", "#5b6f55", "#99c5c4", "#332e2e", "#7b4d3a", "#536267", "#eff0d3", "#f4d493",
    "#fcd917", "#e16233", "#f8e0e7", "#e59b34", "#ebe5d0", "#393540", "#e4f3e0", "#d6d7d2",
    "#c19a13", "#d29380", "#babfbc", "#3b638c", "#ffe29b", "#99eeff", "#eebb33", "#4a3b6a",
    "#c6bbdb", "#ab6f60", "#ff9b87", "#b08f42", "#a67283", "#b1832f", "#fedbb7", "#fcd7ba",
    "#ee3366", "#89a203", "#484a46", "#f878f8", "#b66325", "#c1f80a", "#6dbac0", "#4b373a",
    "#03012d", "#ff2600", "#555570", "#ff7a00", "#8edacc", "#ffcc77", "#cfac47", "#a15325",
    "#ff4466", "#f9f1dd", "#816d5e", "#5f6957", "#f3e0d8", "#006380", "#c26157", "#f9e3b4",
    "#c88ca4", "#b87333", "#ea9073", "#ee1133", "#e4d9c5", "#dbe7e3", "#ff0e0e", "#eebe1b",
    "#d8caa9", "#9bc2b1", "#b0003c", "#bae5d6", "#e38fac", "#f6cbca", "#ee4433", "#73383c",
    "#3f4250", "#000066", "#ffff33", "#bda58b", "#e0b0ff", "#acddaf", "#a9afaa", "#cee1f2",
    "#7ad7ad", "#e5dae1", "#906a54", "#938b4b", "#86c4da", "#a17a83", "#008e80", "#ebebeb",
    "#883377", "#9a0eea", "#11cc55", "#eecc44", "#aaff32", "#e2c9ce", "#f2ab46", "#fd8f79",
    "#92898a", "#787489", "#a6ab9b", "#cef0cc", "#443388", "#fedc57", "#ed4b00", "#a58459",
    "#553311", "#ffb07c", "#d4ffff", "#534b4f", "#74857f", "#007fff", "#332266", "#bc6f37",
    "#aaaa77", "#cce2f3", "#fff8dc", "#5c5d5d", "#f3f4d9", "#c7bba4", "#cf758a", "#fbec5d",
    "#fffbf8", "#b7d2e3", "#eeee66", "#f6efe1", "#ffe39b", "#4e312d", "#e75480", "#bbb3a2",
    "#3c2f23", "#8f7f85", "#e3cdc2", "#f3efcd", "#152eff", "#d9eae5", "#dabe82", "#ce2029",
];

fn hex_to_rgb(hex: &str) -> Option<Rgb<u8>> {
    if !hex.starts_with('#') || hex.len() != 7 {
        return None;
    }

    let r = u8::from_str_radix(&hex[1..3], 16).ok()?;
    let g = u8::from_str_radix(&hex[3..5], 16).ok()?;
    let b = u8::from_str_radix(&hex[5..7], 16).ok()?;

    Some(Rgb([r, g, b]))
}

fn hash_to_color_indices(hash: &[u8]) -> Vec<usize> {
    hash.iter().map(|&byte| byte as usize % COLORS.len()).collect()
}

fn create_image_from_indices(indices: &[usize], width: u32, height: u32) -> ImageBuffer<Rgb<u8>, Vec<u8>> {
    let mut img = ImageBuffer::new(width, height);
    let num_pixels = width * height;

    for y in 0..height {
        for x in 0..width {
            let pixel_index = (y * width + x) as usize;
            let color_index = indices[pixel_index % indices.len()];
            if let Some(color) = hex_to_rgb(COLORS[color_index]) {
                img.put_pixel(x, y, color);
            } else {
                // Fallback to black if color conversion fails
                img.put_pixel(x, y, Rgb([0, 0, 0]));
            }
        }
    }
    img
}

fn sha256_to_png(hash_str: &str, output_path: &str, width: u32, height: u32) -> Result<(), image::ImageError> {
    let mut hasher = Sha256::new();
    hasher.update(hash_str.as_bytes());
    let result = hasher.finalize();
    let hash_bytes = result.as_slice();

    let color_indices = hash_to_color_indices(hash_bytes);
    let image = create_image_from_indices(&color_indices, width, height);
    image.save(output_path)
}

fn main() -> Result<(), image::ImageError> {
    let hash_input = "This is some data to hash";
    let output_file = "hash_image.png";
    let image_width = 256;
    let image_height = 128;

    println!("Hashing: {}", hash_input);
    println!("Creating image: {}", output_file);

    sha256_to_png(hash_input, output_file, image_width, image_height)?;

    println!("Image created successfully!");

    Ok(())
}