ant design v3 颜色转换函数

antd_color.dart

Color calcAntdColor(Color color, int index) {
  var helper = _AntdColorHelper.instance;
  var isLight = index <= 6;
  var hsv = HSVColor.fromColor(color);
  int i = isLight
      ? _AntdColorHelper.lightColorCount + 1 - index
      : index - _AntdColorHelper.lightColorCount - 1;

  return HSVColor.fromAHSV(
          color.opacity,
          helper.getHue(hsv, i, isLight),
          helper.getSaturation(hsv, i, isLight),
          helper.getValue(hsv, i, isLight).roundToDouble())
      .toColor();
}

class _AntdColorHelper {
  static const hueStep = 2;
  static const saturationStep = 16;
  static const saturationStep2 = 5;
  static const brightnessStep1 = 5;
  static const brightnessStep2 = 15;
  static const lightColorCount = 5;
  static const darkColorCount = 4;

  const _AntdColorHelper();

  static _AntdColorHelper instance = _AntdColorHelper();

  double getHue(HSVColor hsv, int i, bool isLight) {
    double hue;
    if (hsv.hue >= 60 && hsv.hue <= 240) {
      hue = isLight ? hsv.hue - hueStep * i : hsv.hue + hueStep * i;
    } else {
      hue = isLight ? hsv.hue + hueStep * i : hsv.hue - hueStep * i;
    }
    if (hue < 0) {
      hue += 360;
    } else if (hue >= 360) {
      hue -= 360;
    }
    return hue;
  }

  double getSaturation(HSVColor hsv, int i, bool isLight) {
    double saturation;
    if (isLight) {
      saturation = (hsv.saturation * 100) - saturationStep * i;
    } else if (i == darkColorCount) {
      saturation = (hsv.saturation * 100) + saturationStep;
    } else {
      saturation = (hsv.saturation * 100) + saturationStep2 * i;
    }
    if (saturation > 100) {
      saturation = 100;
    }
    if (isLight && i == lightColorCount && saturation > 10) {
      saturation = 10;
    }
    if (saturation < 6) {
      saturation = 6;
    }
    return saturation;
  }

  int getValue(HSVColor hsv, int i, bool isLight) {
    if (isLight) {
      return (hsv.value * 100).round() + brightnessStep1 * i;
    }
    return (hsv.value * 100).round() - brightnessStep2 * i;
  }
}