public static float[] GetRGBManhattanLengthTo(this Bitmap a, Bitmap b)
{
if (a.Width != b.Width || a.Height != b.Height)
{
throw new ArgumentException("bitmaps must be of same size", nameof(b));
}
var mlenghs = new List <float>();
for (int i = 0; i < a.Data.Length; i += 4)
{
var av = a.Data.GetVec4(i);
var bv = b.Data.GetVec4(i);
bool isTransparent = av.W == 0 || bv.W == 0;
var rgb = isTransparent ? 0.0f : Vec4.Abs(bv - av)
.GetVec3()
.LengthManhattan();
mlenghs.Add(rgb);
}
return(mlenghs.ToArray());
}