public static ArgusColor GetDominantColor(this Surface surface, ArgusColor minValue, ArgusColor maxValue, byte maxDeviation = 10, int maxIterations = 100, Rectangle[] rois = null, Effect callingEffect = null)
{
Pair <ArgusColor, ArgusColor> meanAndDev = surface.GetMeanAndStdDeviation(minValue, maxValue, rois, callingEffect);
ArgusColor dev = meanAndDev.Second;
ArgusColor mean = meanAndDev.First;
int count = 1;
while (!(callingEffect?.IsCancelRequested ?? false) && count < maxIterations && (dev.R > maxDeviation || dev.G > maxDeviation || dev.B > maxDeviation || dev.A > maxDeviation))
{
minValue.R = (byte)Math.Max(0, mean.R - dev.R);
minValue.G = (byte)Math.Max(0, mean.G - dev.G);
minValue.B = (byte)Math.Max(0, mean.B - dev.B);
minValue.A = (byte)Math.Max(0, mean.A - dev.A);
maxValue.R = (byte)Math.Min(255, mean.R + dev.R);
maxValue.G = (byte)Math.Min(255, mean.G + dev.G);
maxValue.B = (byte)Math.Min(255, mean.B + dev.B);
maxValue.A = (byte)Math.Min(255, mean.A + dev.A);
meanAndDev = surface.GetMeanAndStdDeviation(minValue, maxValue, rois, callingEffect);
mean = meanAndDev.First;
dev = meanAndDev.Second;
count++;
}
return(mean);
}
/// <summary>
/// Implements: https://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Computing_shifted_data
/// </summary>
/// <param name="surface"></param>
/// <param name="rects"></param>
/// <param name="stdDeviation"></param>
/// <returns>The mean color.</returns>
public static Pair <ArgusColor, ArgusColor> GetMeanAndStdDeviation(this Surface surface, ArgusColor minValue, ArgusColor maxValue, Rectangle[] rois = null, Effect callingEffect = null)
{
rois = rois ?? new Rectangle[] { surface.Bounds };
object _lock = new object();
double r_tot = 0;
double g_tot = 0;
double b_tot = 0;
double a_tot = 0;
double r2_tot = 0;
double g2_tot = 0;
double b2_tot = 0;
double a2_tot = 0;
long n_tot = 0;
ColorBgra K = surface[rois[0].Left, rois[0].Top];
Parallel.For(0, rois.Length, (i, loopStateI) =>
{
if (callingEffect?.IsCancelRequested ?? false)
{
loopStateI.Stop();
return;
}
Rectangle rect = rois[i];
Parallel.For(rect.Top, rect.Bottom, (y, loopStateY) =>
{
if (callingEffect?.IsCancelRequested ?? false)
{
loopStateY.Stop();
return;
}
double r = 0;
double g = 0;
double b = 0;
double a = 0;
double r2 = 0;
double g2 = 0;
double b2 = 0;
double a2 = 0;
long n = 0;
for (int x = rect.Left; x < rect.Right; x++)
{
ColorBgra c = surface[x, y];
if (c.R < minValue.R || c.R > maxValue.R)
{
continue;
}
if (c.G < minValue.G || c.G > maxValue.G)
{
continue;
}
if (c.B < minValue.B || c.B > maxValue.B)
{
continue;
}
if (c.A < minValue.A || c.A > maxValue.A)
{
continue;
}
int v = c.R - K.R;
r += v;
r2 += v * v;
v = c.G - K.G;
g += v;
g2 += v * v;
v = c.B - K.B;
b += v;
b2 += v * v;
v = c.A - K.A;
a += v;
a2 += v * v;
n++;
}
lock (_lock)
{
r_tot += r;
r2_tot += r2;
g_tot += g;
g2_tot += g2;
b_tot += b;
b2_tot += b2;
a_tot += a;
a2_tot += a2;
n_tot += n;
}
});
});
n_tot = Math.Max(1, n_tot);
var mean = new ArgusColor
{
R = (byte)Math.Round(r_tot / n_tot + K.R),
G = (byte)Math.Round(g_tot / n_tot + K.G),
B = (byte)Math.Round(b_tot / n_tot + K.B),
A = (byte)Math.Round(a_tot / n_tot + K.A)
};
double devR = Math.Round(Math.Sqrt((r2_tot - (r_tot * r_tot / n_tot)) / n_tot));
double devG = Math.Round(Math.Sqrt((g2_tot - (g_tot * g_tot / n_tot)) / n_tot));
double devB = Math.Round(Math.Sqrt((b2_tot - (b_tot * b_tot / n_tot)) / n_tot));
double devA = Math.Round(Math.Sqrt((a2_tot - (a_tot * a_tot / n_tot)) / n_tot));
var dev = new ArgusColor((byte)devR, (byte)devG, (byte)devB, (byte)devA);
return(new Pair <ArgusColor, ArgusColor>(mean, dev));
}
public static async Task <ArgusColor> GetDominantColorAsync(this Surface surface, ArgusColor minValue, ArgusColor maxValue, byte maxDeviation = 10, int maxIterations = 100, Rectangle[] rois = null, Effect callingEffect = null)
{
return(await Task.Run(() => { return surface.GetDominantColor(minValue, maxValue, maxDeviation, maxIterations, rois, callingEffect); }));
}
public static async Task <Pair <ArgusColor, ArgusColor> > GetMeanAndStdDeviationAsync(this Surface surface, ArgusColor minValue, ArgusColor maxValue, Rectangle[] rois = null, Effect callingEffect = null)
{
return(await Task.Run(() => { return surface.GetMeanAndStdDeviation(minValue, maxValue, rois, callingEffect); }));
}