darker method
Make color darker by so many percents
Implementation
Color darker(int percents) {
assert(percents >= 1 && percents <= 100);
final int rgbPercent = (percents / 100 * 255).round();
int red = this.red - rgbPercent,
green = this.green - rgbPercent,
blue = this.blue - rgbPercent;
if (red < 0) {
red = 0;
}
if (green < 0) {
green = 0;
}
if (blue < 0) {
blue = 0;
}
return Color.fromARGB(alpha, red, green, blue);
}