Code to generate an image which will show differently when expanded on Discord. (standard dark theme) Bad code, doesn't really deserve a repo of its own. Available in website form at https://discordimage.19wintersp.repl.co/

discord_double_image.rs

// depends on https://crates.io/crates/image ^0.23

use std::env::args;
use std::process::exit;

use image::{ GenericImageView, GrayImage, ImageResult, RgbaImage };
use image::imageops::FilterType;

const BRIGHTNESS_THRESHOLD: u8 = 64;
const COLOUR_A: [u8; 4] = [ 8, 8, 9, 255 ];
const COLOUR_B: [u8; 4] = [ 54, 57, 63, 255 ];
const MAXIMUM_SIZE: u32 = 256;

fn main() -> ImageResult<()> {
	let args: Vec<_> = args().collect();

	if args.len() < 3 {
		eprintln!("Usage: {} <image_a> <image_b> [output]", args[0]);
		exit(1);
	}

	let mut image_a = image::open(&args[1])?.grayscale();
	let mut image_b = image::open(&args[2])?.grayscale();
	
	if image_a.width() > MAXIMUM_SIZE || image_a.height() > MAXIMUM_SIZE {
		image_a = image_a.resize(MAXIMUM_SIZE, MAXIMUM_SIZE, FilterType::Nearest);
	}
	
	if image_b.width() > MAXIMUM_SIZE || image_b.height() > MAXIMUM_SIZE {
		image_b = image_b.resize(MAXIMUM_SIZE, MAXIMUM_SIZE, FilterType::Nearest);
	}

	let image_a = image_a.to_luma8();
	let image_b = image_b.to_luma8();

	let width = image_a.width().max(image_b.width());
	let height = image_a.height().max(image_b.height());

	let mut output = RgbaImage::new(width, height);

	for x in 0..width {
		for y in 0..height {
			let i = x % 2 == y % 2;

			let a = get_pixel(&image_a, x, y) < BRIGHTNESS_THRESHOLD && i;
			let b = get_pixel(&image_b, x, y) < BRIGHTNESS_THRESHOLD && !i;
			
			let pixel = if a {
				COLOUR_A
			} else if b {
				COLOUR_B
			} else {
				[ 0, 0, 0, 0 ]
			};

			output.put_pixel(x, y, pixel.into());
		}
	}

	output.save(if args.len() >= 4 {
		&args[3]
	} else {
		"output.png"
	})?;

	Ok(())
}

fn get_pixel(image: &GrayImage, x: u32, y: u32) -> u8 {
	if x >= image.width() || y >= image.height() {
		255
	} else {
		image.get_pixel(x, y).0[0]
	}
}