toHex method
Prefixes a hash sign if leadingHashSign is set to true (default is true).
Implementation
String toHex({bool leadingHashSign = true}) =>
'${leadingHashSign ? '#' : ''}'
'${a.toInt().toRadixString(16).padLeft(2, '0')}'
'${r.toInt().toRadixString(16).padLeft(2, '0')}'
'${g.toInt().toRadixString(16).padLeft(2, '0')}'
'${b.toInt().toRadixString(16).padLeft(2, '0')}';