21 QRgb rgbBackground)
const
23 double distance = qSqrt (pow (
double (pixel.red()) - qRed (rgbBackground), 2) +
24 pow (
double (pixel.green()) - qGreen (rgbBackground), 2) +
25 pow (
double (pixel.blue()) - qBlue (rgbBackground), 2));
26 return distance / qSqrt (255.0 * 255.0 + 255.0 * 255.0 + 255.0 * 255.0);