code: func (c Color) RGB() (int32, int32, int32) {
  	v := c.Hex()
  	if v < 0 {
  		return -1, -1, -1
  	}
  	return (v >> 16) & 0xff, (v >> 8) & 0xff, v & 0xff
  }
docs: // RGB returns the red, green, and blue components of the color, with
  // each component represented as a value 0-255.  In the event that the
  // color cannot be broken up (not set usually), -1 is returned for each value.