self.addEventListener('message', function (e) {


  const { data: { i, arr: pixels } } = e;

  let store = {};

  let total = pixels.length / 4;

  const threshold = 200;

  for (let i = 0; i < total; i++) {
    const r = pixels[i * 4 + 0] > threshold ? 1 : 0;
    const g = pixels[i * 4 + 1] > threshold ? 1 : 0;
    const b = pixels[i * 4 + 2] > threshold ? 1 : 0;
    const id = r + "-" + g + "-" + b;
    store[id] = store[id] + 1 || 1;
  }


  Object.keys(store).forEach(k => {
    store[k] = store[k] / total;
  });


  self.postMessage({ res: store, i });
}, false);