docs: function(r, g, b, a) {
  		var rnum = typeof r === "number";
  		if (rnum
  				&& typeof g === "number"
  				&& typeof b === "number") {
  			//default alpha to one 
  			a = typeof a === "number" ? a : 1.0;
  		} else {
  			r = g = b = a = rnum ? r : 1.0;
  		}
  		
  		if (this.premultiplied) {
  			r *= a;
  			g *= a;
  			b *= a;
  		}
  		
  		this.color = colorToFloat(
  			~~(r * 255),
  			~~(g * 255),
  			~~(b * 255),
  			~~(a * 255)
  		);
  	}