text: const Color = require('../Color');
  
  Color.prototype.premultiply = function(mutate=false) {
  	const rgb = this._rgb;
  	const a = rgb[3];
  	if (mutate) {
  		this._rgb = [rgb[0]*a, rgb[1]*a, rgb[2]*a, a];
  		return this;
  	} else {
  		return new Color([rgb[0]*a, rgb[1]*a, rgb[2]*a, a], 'rgb');
  	}
  }
  