type floydSteinberg struct{}

func (floydSteinberg) Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point) {
	clip(dst, &r, src, &sp, nil, nil)
	if r.Empty() {
		return
	}
	drawPaletted(dst, r, src, sp, true)
}

// clip clips r against each image's bounds (after translating into the
// destination image's coordinate space) and shifts the points sp and mp by
// the same amount as the change in r.Min.