getBtnSize method
Get button size (eg. small,medium,large)
Implementation
double getBtnSize() {
if (BtnSize.tiny == size) return .7;
if (BtnSize.small == size) return 1;
if (BtnSize.medium == size) return 1.5;
if (BtnSize.large == size) return 1.8;
return 1.3;
}