package.json

{
  "devDependencies": {
    "babel-cli": "^6.4.5",
    "babel-core": "^6.4.5",
    "babel-preset-es2015": "^6.3.13"
  },
  "dependencies": {
    "canvas": "^1.3.9"
  }
}

print.js

const Canvas = require('canvas'),
      fs = require('fs'),
      child_process = require('child_process'),
      spawn = child_process.spawn
;


function fitText(text, {canvas, start, padding, style}) {
  const ctx = canvas.getContext('2d');
  let iteration = start;

  ctx.font = style(iteration);

  while (ctx.measureText(text).width > (canvas.width - (padding * 2))) {
    iteration -= 2;
    ctx.font = style(iteration);
    if (iteration <= 10) break;
  }

  return [ctx.measureText(text).width, style(iteration)];
}

function renderBadge({firstName, lastName, ticketType, badge}) {
    const canvas = new Canvas();
    canvas.width = badge.width;
    canvas.height = badge.height;

    //Print first name
    (() => {
        const ctx = canvas.getContext('2d');
        let width = 0;
        let size = 120;
        const padding = 5;
        [width, ctx.font] = fitText(firstName, {
            canvas,
            padding,
            start: size,
            style: size => `bold ${size}px Helvetica Neue`
        });
        ctx.fillText(firstName,  ((canvas.width - width) / 2) - padding/2, (canvas.height/2 - size/2));
    })();

    //Print last name
    (() => {
        const ctx = canvas.getContext('2d');
        let width = 0;
        let size = 60;
        const padding = 5;
        [width, ctx.font] = fitText(lastName, {
            canvas,
            padding,
            start: size,
            style: size => `${size}px Helvetica Neue`
        });
        ctx.fillText(lastName,  ((canvas.width - width) / 2) - padding/2, (canvas.height/2 + size/2));
    })();

    return canvas;
}

const badge = renderBadge({
    firstName: "Daniel",
    lastName: "Cousineau",
    type: "Organizer",
    badge: {
        width: 700,
        height: 300
    }
});


const out = fs.createWriteStream(__dirname + '/badge.png');
const stream = badge.pngStream();

stream.on('data', chunk => {
  out.write(chunk);
});

stream.on('end', () => {
  child_process.exec('lp -d Brother_QL_700 -o media=Custom.2.4x1.5in ./badge.png', () => {
    console.log('done');
  })
});