calculateScaleFactor function
rescale the old cards based on its position
Implementation
double calculateScaleFactor(
List<MuqSnackbar> toastBars, MuqSnackbar current) {
int index = toastBars.indexOf(current);
int indexValFromLast = toastBars.length - 1 - index;
double factor = indexValFromLast / 25;
double res = 0.97 - factor;
return res < 0 ? 0 : res;
}