darken function
Darken a color
by percent
Implementation
Color darken(Color color, double percent) {
assert(percent <= 100, 'Darken percent should not be greater than 100');
final strength = 1 - percent / 100;
return Color.fromARGB(
color.alpha,
(color.red * strength).round(),
(color.green * strength).round(),
(color.blue * strength).round(),
);
}