Spiraling Braille

readme.md

An experiment with Braille unicode chars in terminal.

run npx https://gist.github.com/subzey/355eff6cef3d4c835e81dec7eb3e7f83 in your terminal

index.js

#!/usr/bin/env node
if (!process.stdout.isTTY) {
	process.stderr.write('stdout is not a terminal');
	process.exit(1);
}

const clearScreenSeq = '\u001b[H\u001b[2J';
const clearScreenSeqLen = Buffer.byteLength(clearScreenSeq);

const maths = (x, y, now, tie) => {
	const angle = Math.atan2(x, y);
	const dist = Math.hypot(x, y);
	const phase = Math.cos(now / -2 + dist / 20) * 4 + now;
	return Math.cos(phase + angle * 6) > tie;
}

const frame = () => {
	const height = process.stdout.rows;
	const width = process.stdout.columns;

	const buf = new Buffer(width * height * 3 + height - 1 + clearScreenSeqLen);
	let ptr = 0;
	ptr = buf.write(clearScreenSeq);

	const now = Date.now() / 500;

	for (let row = 0; row < height; row++) {
		const y = row * 2 - height;
		for (let column = 0; column < width; column++) {
			const x = column - width / 2;
			const crossCharTie = column % 2 ? .8 : 1.25;

			buf[ptr] = 0xE2;
			buf[ptr + 1] = (
				0xA0
			|
				maths(x + .25, y + 1.75, now, .6 * crossCharTie)
			|
				maths(x + .75, y + 1.75, now, -.6 * crossCharTie) << 1
			);
			buf[ptr + 2] = (
				0x80
			|
				maths(x + .25, y + .25, now, -.3)
			|
				maths(x + .25, y + .75, now, .6) << 1
			|
				maths(x + .25, y + 1.25, now, -.3 * crossCharTie) << 2
			|
				maths(x + .75, y + .25, now, .3) << 3
			|
				maths(x + .75, y + .75, now, -.6) << 4
			|
				maths(x + .75, y + 1.25, now, .3 * crossCharTie) << 5
			);
			ptr += 3;
		}
		if (row < height - 1) {
			buf[ptr] = 0x0A;
			ptr++;
		}
	}

	setTimeout(frame, 33);
	process.stdout.write(buf);
}

frame();

package.json

{ "private": true, "main": "index.js", "name": "bpiraling-braille", "version": "0.0.1", "bin": "index.js" }