private static bool CheckColor(LabColor color, PaletteOptions options)
{
var rgb = color.ToRgb();
var hcl = color.ToHcl();
var compLab = rgb.ToLab();
var labTolerance = 7;
return(
hcl.H >= options.HueMin &&
hcl.H <= options.HueMax &&
hcl.C >= options.ChromaMin &&
hcl.C <= options.ChromaMax &&
hcl.L >= options.LightMin &&
hcl.L <= options.LightMax &&
compLab.L >= (color.L - labTolerance) &&
compLab.L <= (color.L + labTolerance) &&
compLab.A >= (color.A - labTolerance) &&
compLab.A <= (color.A + labTolerance) &&
compLab.B >= (color.B - labTolerance) &&
compLab.B <= (color.B + labTolerance)
);
}
// WARNING: may return [NaN, NaN, NaN]
private LabColor Simulate(LabColor lab, ColorDistanceType type, int amount = 1)
{
// Cache
var key = string.Format("{0}-{1}{2}", lab, type, amount);
if (this.simulateCache.ContainsKey(key))
{
return this.simulateCache[key];
}
// Get data from type
var confuse = ConfusionLine.Get(type);
// Code adapted from http://galacticmilk.com/labs/Color-Vision/Javascript/Color.Vision.Simulate.js
var color = lab.ToRgb();
var sr = color.R;
var sg = color.G;
var sb = color.B;
double dr = sr; // destination color
double dg = sg;
double db = sb;
// Convert source color into XYZ color space
var pow_r = Math.Pow(sr, 2.2);
var pow_g = Math.Pow(sg, 2.2);
var pow_b = Math.Pow(sb, 2.2);
var X = pow_r * 0.412424 + pow_g * 0.357579 + pow_b * 0.180464; // RGB->XYZ (sRGB:D65)
var Y = pow_r * 0.212656 + pow_g * 0.715158 + pow_b * 0.0721856;
var Z = pow_r * 0.0193324 + pow_g * 0.119193 + pow_b * 0.950444;
// Convert XYZ into xyY Chromacity Coordinates (xy) and Luminance (Y)
var chroma_x = X / (X + Y + Z);
var chroma_y = Y / (X + Y + Z);
// Generate the "Confusion Line" between the source color and the Confusion Point
var m = (chroma_y - confuse.Y) / (chroma_x - confuse.X); // slope of Confusion Line
var yint = chroma_y - chroma_x * m; // y-intercept of confusion line (x-intercept = 0.0)
// How far the xy coords deviate from the simulation
var deviate_x = (confuse.Yint - yint) / (m - confuse.M);
var deviate_y = (m * deviate_x) + yint;
// Compute the simulated color's XYZ coords
X = deviate_x * Y / deviate_y;
Z = (1.0 - (deviate_x + deviate_y)) * Y / deviate_y;
// Neutral grey calculated from luminance (in D65)
var neutral_X = 0.312713 * Y / 0.329016;
var neutral_Z = 0.358271 * Y / 0.329016;
// Difference between simulated color and neutral grey
var diff_X = neutral_X - X;
var diff_Z = neutral_Z - Z;
var diff_r = diff_X * 3.24071 + diff_Z * -0.498571; // XYZ->RGB (sRGB:D65)
var diff_g = diff_X * -0.969258 + diff_Z * 0.0415557;
var diff_b = diff_X * 0.0556352 + diff_Z * 1.05707;
// Convert to RGB color space
dr = X * 3.24071 + Y * -1.53726 + Z * -0.498571; // XYZ->RGB (sRGB:D65)
dg = X * -0.969258 + Y * 1.87599 + Z * 0.0415557;
db = X * 0.0556352 + Y * -0.203996 + Z * 1.05707;
// Compensate simulated color towards a neutral fit in RGB space
var fit_r = ((dr < 0.0 ? 0.0 : 1.0) - dr) / diff_r;
var fit_g = ((dg < 0.0 ? 0.0 : 1.0) - dg) / diff_g;
var fit_b = ((db < 0.0 ? 0.0 : 1.0) - db) / diff_b;
var adjust = Math.Max( // highest value
Math.Max(
(fit_r > 1.0 || fit_r < 0.0) ? 0.0 : fit_r,
(fit_g > 1.0 || fit_g < 0.0) ? 0.0 : fit_g),
(fit_b > 1.0 || fit_b < 0.0) ? 0.0 : fit_b
);
// Shift proportional to the greatest shift
dr = dr + (adjust * diff_r);
dg = dg + (adjust * diff_g);
db = db + (adjust * diff_b);
// Apply gamma correction
dr = Math.Pow(dr, 1.0 / 2.2);
dg = Math.Pow(dg, 1.0 / 2.2);
db = Math.Pow(db, 1.0 / 2.2);
// Anomylize colors
dr = sr * (1.0 - amount) + dr * amount;
dg = sg * (1.0 - amount) + dg * amount;
db = sb * (1.0 - amount) + db * amount;
var dcolor = Color.FromArgb(
(int)Math.Round(dr),
(int)Math.Round(dg),
(int)Math.Round(db));
var result = dcolor.ToLab();
this.simulateCache[key] = result;
return result;
}
