isDarkHsp function
Function to determine if a color is dark tone. It's based on HSP Color Model color: Argument to determine its status
Implementation
bool? isDarkHsp(Color? color) {
if (color == null) return null;
int _redValue = color.red;
int _greenValue = color.green;
int _blueValue = color.blue;
double _hsp = sqrt(rConstant * pow(_redValue, 2) +
gConstant * pow(_greenValue, 2) +
bConstant * pow(_blueValue, 2));
return _hsp < hspBoundary;
}