code: func gradient(from, to color.RGBA, scale float64) (result color.RGBA) {
  	scale = math.Max(math.Min(scale, 1.0), 0.0)
  	result.R = linearScale(from.R, to.R, scale)
  	result.G = linearScale(from.G, to.G, scale)
  	result.B = linearScale(from.B, to.B, scale)
  	return
  }
docs: // gradient produces a color between from and to colors
  // given a scale between 0.0 to 1.0, with each of the color
  // components multiplied.