public void RgbToXyz(int[] rgb, double[] xyz)
{
var rgbColor = Color.FromArgb(rgb[0], rgb[1], rgb[2]);
Assert.Equal(
new XyzColor(xyz[0], xyz[1], xyz[2]),
XyzColor.FromRgb(rgbColor)
);
}
public IEnumerable <Color> PickColors(Bitmap bitmap, int count)
{
var(thumb, width, height) = Resize(bitmap, 72);
using (thumb)
{
var colors = GetColors(thumb, width, height);
var xyzColors = colors.Select(x => XyzColor.FromRgb(x));
var labColors = xyzColors.Select(x => CieLabColor.FromXyz(x));
var labSpace = new CieLabSpace();
var selections = KmeansPlusPlus(labColors.ToArray(), labSpace, count, _seed);
return(selections.Select(x => labSpace.GetCentroid(x)).Select(x => x.ToXyzColor().ToRgbColor()));
}
}
public static CieLabColor FromXyz(XyzColor color)
{
double F(double t) => t > 0.00885645167903563/* Math.Pow(Delta, 3) */
? Math.Pow(t, 1.0 / 3.0)
: 7.78703703703704 /* 1.0 / (3.0 * Math.Pow(Delta, 2))*/ * t + 0.137931034482759 /* 4.0 / 29.0 */;
var x = color.X * 100;
var y = color.Y * 100;
var z = color.Z * 100;
var fYPerYn = F(y / Yn);
return(new CieLabColor
(
Math.Round(116.0 * fYPerYn - 16.0, 4),
Math.Round(500.0 * (F(x / Xn) - fYPerYn), 4),
Math.Round(200.0 * (fYPerYn - F(z / Zn)), 4)
));
}
