This is a simple program that generates a random walk visualization for laser etching on train whistles. Ported from CodingTrain/Random-Whistle

README.md

How to test directly:

1. download these files
2. npm install p5 canvas jsdom
3. node sketch.js <any-random-seed-here>
4. randomwalk will be saved as walk.png

functions.js

const fs = require("fs");
async function saveAsPNG(p5Inst, filename = "sketch") {
  const buffer = p5Inst._renderer.drawingContext.canvas.toBuffer()
  await fs.promises.writeFile(filename + ".png", buffer)
}

function getBuffer(p5Inst) {
  return p5Inst._renderer.drawingContext.canvas.toBuffer()
}

const { createCanvas } = require("canvas");
const { JSDOM } = require("jsdom")
const { performance } = require("perf_hooks")
function setupWindow(w, h) {

  global.window = global

  const dom = new JSDOM()
  global.document = dom.window.document

  const nodeCanvas = createCanvas(w, h)
  dom.window.HTMLCanvasElement.prototype.getContext = (type) => {
    return nodeCanvas.getContext(type)
  };

  global.performance = performance

  global.screen = {}

  global.addEventListener = dom.window.addEventListener.bind(dom.window)
  global.removeEventListener = dom.window.removeEventListener.bind(dom.window)

  global.navigator = { userAgent: "node" }

}

module.exports = { saveAsPNG, getBuffer, setupWindow }

sketch.js

const w = 4880, h = 1500;
const { saveAsPNG, setupWindow } = require("./functions");
setupWindow(w, h)
global.setup = setup;
const p5 = require("p5");


let x;
let y;

// let whistle;
let number = process.argv[2] || 123456;


function setup() {
  createCanvas(w, h);
  // whistle = createGraphics(4880, 1500);
  pixelDensity(1);
  background(255);
  x = width / 2;
  y = height / 2;
  const stepSize = 4;
  randomSeed(number);
  for (let i = 0; i < 1000000; i++) {
    //canvas.stroke(0);
    //canvas.point(x, y);
    noStroke();
    fill(0);
    rectMode(CENTER);
    rect(x, y, stepSize, stepSize);
    strokeWeight(stepSize);
    const r = int(random(4));

    switch (r) {
      case 0:
        x = x + stepSize;
        break;
      case 1:
        x = x - stepSize;
        break;
      case 2:
        y = y + stepSize;
        break;
      case 3:
        y = y - stepSize;
        break;
    }
  }
  saveAsPNG(global, "walk");
  remove();
}