private float CalculateDistance(UnityEngine.Rect rect, NormalizedLandmark a, NormalizedLandmark b)
        {
            var aPos = rect.GetPoint(a, rotationAngle, isMirrored);
            var bPos = rect.GetPoint(b, rotationAngle, isMirrored);

            aPos.z = 0.0f;
            bPos.z = 0.0f;
            return(Vector3.Distance(aPos, bPos));
        }