dart - 以编程方式使 dart 中的十六进制颜色变亮或变暗

Question

我正在尝试转换此哈希颜色代码 #159424 (绿色) 以编程方式更暗和更亮。如何做到这一点，请帮忙？

使绿色更深

toDarkColor(String hashColor){
  // how to convert that hash string to make green color darker?
}

让绿色更亮

toLightColor(String hashColor){
  // how to convert that hash string to make green color lighter? 
}

Answer 1

对于想要变暗或变亮的人Color而不是十六进制字符串

// ranges from 0.0 to 1.0

Color darken(Color color, [double amount = .1]) {
  assert(amount >= 0 && amount <= 1);

  final hsl = HSLColor.fromColor(color);
  final hslDark = hsl.withLightness((hsl.lightness - amount).clamp(0.0, 1.0));

  return hslDark.toColor();
}

Color lighten(Color color, [double amount = .1]) {
  assert(amount >= 0 && amount <= 1);

  final hsl = HSLColor.fromColor(color);
  final hslLight = hsl.withLightness((hsl.lightness + amount).clamp(0.0, 1.0));

  return hslLight.toColor();
}

// usage
final lightRed = lighten(Colors.red);
final darkBlue = darken(Colors.blue, .3);

Live Demo