getColorFromHsl static method

int getColorFromHsl(double h, double s, double l, double opacity,)

Implementation

static int getColorFromHsl(double h, double s, double l, double opacity) {
  List<double> rgb = [0, 0, 0];

  final double hue = h / 360 % 1;
  final double saturation = s / 100;
  final double luminance = l / 100;

  if (hue < 1 / 6) {
    rgb[0] = 1;
    rgb[1] = hue * 6;
  } else if (hue < 2 / 6) {
    rgb[0] = 2 - hue * 6;
    rgb[1] = 1;
  } else if (hue < 3 / 6) {
    rgb[1] = 1;
    rgb[2] = hue * 6 - 2;
  } else if (hue < 4 / 6) {
    rgb[1] = 4 - hue * 6;
    rgb[2] = 1;
  } else if (hue < 5 / 6) {
    rgb[0] = hue * 6 - 4;
    rgb[2] = 1;
  } else {
    rgb[0] = 1;
    rgb[2] = 6 - hue * 6;
  }

  rgb = rgb.map((val) => val + (1 - saturation) * (0.5 - val)).toList();

  if (luminance < 0.5) {
    rgb = rgb.map((val) => luminance * 2 * val).toList();
  } else {
    rgb = rgb.map((val) => luminance * 2 * (1 - val) + 2 * val - 1).toList();
  }

  final resultRgb = rgb.map((val) => (val * 255).round()).toList();

  return ((((opacity * 0xff ~/ 1) & 0xff) << 24) |
          ((resultRgb[0] & 0xff) << 16) |
          ((resultRgb[1] & 0xff) << 8) |
          ((resultRgb[2] & 0xff) << 0)) &
      0xFFFFFFFF;
}