code: function histogram() {
    const histogram = {
      r: new Array(256).fill(0),
      g: new Array(256).fill(0),
      b: new Array(256).fill(0)
    };
  
    this.scanQuiet(0, 0, this.bitmap.width, this.bitmap.height, function(
      x,
      y,
      index
    ) {
      histogram.r[this.bitmap.data[index + 0]]++;
      histogram.g[this.bitmap.data[index + 1]]++;
      histogram.b[this.bitmap.data[index + 2]]++;
    });
  
    return histogram;
  }
docs: Get an image's histogram
  @return {object} An object with an array of color occurrence counts for each channel (r,g,b)