/// <summary>
/// 色が近似的に等価とみなせるか判定する
/// </summary>
/// <param name="a">色その1</param>
/// <param name="b">色その2</param>
/// <param name="hue_tolerance">色相の許容範囲</param>
/// <param name="satulation_tolerance">飽和度の許容範囲</param>
/// <param name="luminance_tolerance">明るさの許容範囲</param>
/// <param name="alpha_tolerance">判定結果</param>
/// <returns>近似的に等価と見做せる場合は true, それ以外は false</returns>
static public bool NearlyEqualsInHSLA
(this Color a, Color b
, PlaneAngle hue_tolerance = null
, double satulation_tolerance = 1.0e-2
, double luminance_tolerance = 1.0e-2
, double alpha_tolerance = 1.0e-2
)
{
var(ha, sa, la, aa) = a.ToHSLA();
var(hb, sb, lb, ab) = b.ToHSLA();
return
(ha.NormalizedNearlyEquals(hb, hue_tolerance ?? PlaneAngle.Degree) &&
sa.NearlyEquals(sb, satulation_tolerance) &&
la.NearlyEquals(lb, luminance_tolerance) &&
aa.NearlyEquals(aa, alpha_tolerance)
);
}
