// Note that if we did error diffusion, we'd actually want to diffuse the
// premultiplied error. However, we need to do dithering in the same
// space as quantization, whether that be pre- or postmultiply.
// Note that if we did error diffusion, we'd actually want to diffuse the
// premultiplied error. However, we need to do dithering in the same
// space as quantization, whether that be pre- or postmultiply.