code: function(color, alpha) {
              color = color.toRGB();
              alpha = Math.min(Math.max(alpha, 0), 1);
              var rgb = this.clone();
  
              rgb.red = (rgb.red * (1 - alpha)) + (color.red * alpha);
              rgb.green = (rgb.green * (1 - alpha)) + (color.green * alpha);
              rgb.blue = (rgb.blue * (1 - alpha)) + (color.blue * alpha);
              rgb.alpha = (rgb.alpha * (1 - alpha)) + (color.alpha * alpha);
  
              return rgb;
          }
docs: /* does an alpha based blend of color onto this. alpha is the
  amount of 'color' to use. (0 to 1)