/// <summary>
/// RGBカラーからLCHカラースベースへ変換する
/// </summary>
/// <param name="rgb">RGBカラー</param>
/// <returns>LCHカラースベース</returns>
internal static Lch ToColor(Rgb rgb)
{
Lch lch = new Lch();
Lab lab = LabConverter.ToColor(rgb);
var h = Math.Atan2(lab.B, lab.A);
if (h > 0)
{
h = (h / Math.PI) * 180.0;
}
else
{
h = 360 - (Math.Abs(h) / Math.PI) * 180.0;
}
if (h < 0)
{
h += 360.0;
}
else if (h >= 360)
{
h -= 360.0;
}
lch.L = lab.L;
lch.C = Math.Sqrt(lab.A * lab.A + lab.B * lab.B);
lch.H = h;
return(lch);
}
/// <summary>
/// RGBカラーからLAB文字列へ変換する
/// </summary>
/// <param name="rgb">RGBカラー</param>
/// <returns>LAB文字列</returns>
public string getLabString(Rgb rgb)
{
Lab lab = LabConverter.ToColor(rgb);
return("L" + ((int)lab.L).ToString()
+ " A" + ((int)lab.A).ToString()
+ " B" + ((int)lab.B).ToString());
}
/// <summary>
/// RGBカラーからMUNSELLカラースベースへ変換する
/// </summary>
/// <param name="rgb">RGBカラー</param>
/// <returns>MUNSELLカラースベース</returns>
internal static Munsell ToColor(Rgb rgb)
{
Munsell item = new Munsell();
Lch lch = LchConverter.ToColor(rgb);
if (rgb.R == rgb.G && rgb.G == rgb.B)
{
Lab lab = LabConverter.ToColor(rgb);
item.H = new MunsellHue {
Base = HueBase.N
};
item.V = Math.Round(ConvertLtoV(lab.L), 1);
return(item);
}
var q = Table.Select(x => new {
diff = Math.Abs(x.Lch.L - lch.L) + Math.Abs(x.Lch.C - lch.C) + Math.Abs(x.Lch.H - lch.H),
self = x
});
var min = q.Min(x => x.diff);
var munsell = q.Where(x => x.diff == min).FirstOrDefault().self;
if (min < 3.0)
{
item.H = munsell.H;
item.V = munsell.V;
item.C = munsell.C;
return(item);
}
var hue = new MunsellHue {
Base = munsell.H.Base, Number = munsell.H.Number
};
MunsellHue newHue;
if (munsell.Lch.H > lch.H)
{
hue.Number -= 2.5;
newHue = new MunsellHue {
Base = hue.Base, Number = hue.Number
};
}
else
{
hue.Number += 2.5;
newHue = new MunsellHue {
Base = munsell.H.Base, Number = munsell.H.Number
};
}
var munsellX = FindMunsell(hue, munsell.V, munsell.C, true);
newHue.Number += Math.Round((lch.H - Math.Min(munsell.Lch.H, munsellX.Lch.H))
/ Math.Abs(munsell.Lch.H - munsellX.Lch.H) * 2.5, 1, MidpointRounding.AwayFromZero);
double newChroma;
//彩度max min
var c = Table.Where(x => x.H == munsell.H && x.V == munsell.V)
.GroupBy(x => x.V).Select(x => new { min = x.Min(y => y.C), max = x.Max(y => y.C) }).First();
if (c.min < munsell.C && munsell.C < c.max)
{
var chroma = munsell.Lch.C > lch.C ? munsell.C - 2.0 : munsell.C + 2.0;
var munsellY = FindMunsell(munsell.H, munsell.V, chroma);
newChroma = Math.Round(Math.Min(munsell.C, munsellY.C) + (lch.C - Math.Min(munsell.Lch.C, munsellY.Lch.C))
/ Math.Abs(munsell.Lch.C - munsellY.Lch.C) * 2.0, 1, MidpointRounding.AwayFromZero);
}
else
{
newChroma = Math.Round(munsell.C / munsell.Lch.C * lch.C, 1, MidpointRounding.AwayFromZero);
}
var newValue = Math.Round(ConvertLtoV(lch.L), 1, MidpointRounding.AwayFromZero);
item.H = newHue;
item.C = newChroma;
item.V = newValue;
return(item);
}