/// <summary>
/// Computes the weighted variance of a box.
/// </summary>
/// <param name="cube">The cube.</param>
/// <returns>The result.</returns>
private double Variance(Box cube)
{
double dr = WuColorQuantizer.Volume(cube, this.vmr);
double dg = WuColorQuantizer.Volume(cube, this.vmg);
double db = WuColorQuantizer.Volume(cube, this.vmb);
double xx = this.m2[WuColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1)]
- this.m2[WuColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0)]
- this.m2[WuColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1)]
+ this.m2[WuColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0)]
- this.m2[WuColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1)]
+ this.m2[WuColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0)]
+ this.m2[WuColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1)]
- this.m2[WuColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0)];
return(xx - (((dr * dr) + (dg * dg) + (db * db)) / WuColorQuantizer.Volume(cube, this.vwt)));
}
/// <summary>
/// Generates the quantized result.
/// </summary>
/// <param name="image">The image.</param>
/// <param name="colorCount">The color count.</param>
/// <param name="cube">The cube.</param>
/// <returns>The result.</returns>
private ColorQuantizerResult GenerateResult(byte[] image, int colorCount, Box[] cube)
{
var quantizedImage = new ColorQuantizerResult(image.Length / 4, colorCount);
for (int k = 0; k < colorCount; k++)
{
this.Mark(cube[k], (byte)k);
double weight = WuColorQuantizer.Volume(cube[k], this.vwt);
if (weight != 0)
{
quantizedImage.Palette[(k * 4) + 3] = 0xff;
quantizedImage.Palette[(k * 4) + 2] = (byte)(WuColorQuantizer.Volume(cube[k], this.vmr) / weight);
quantizedImage.Palette[(k * 4) + 1] = (byte)(WuColorQuantizer.Volume(cube[k], this.vmg) / weight);
quantizedImage.Palette[k * 4] = (byte)(WuColorQuantizer.Volume(cube[k], this.vmb) / weight);
}
else
{
quantizedImage.Palette[(k * 4) + 3] = 0xff;
quantizedImage.Palette[(k * 4) + 2] = 0;
quantizedImage.Palette[(k * 4) + 1] = 0;
quantizedImage.Palette[k * 4] = 0;
}
}
for (int i = 0; i < image.Length / 4; i++)
{
int r = image[(i * 4) + 2] >> (8 - WuColorQuantizer.IndexBits);
int g = image[(i * 4) + 1] >> (8 - WuColorQuantizer.IndexBits);
int b = image[i * 4] >> (8 - WuColorQuantizer.IndexBits);
int ind = WuColorQuantizer.GetIndex(r + 1, g + 1, b + 1);
quantizedImage.Bytes[i] = this.tag[ind];
}
return(quantizedImage);
}
/// <summary>
/// Cuts a box.
/// </summary>
/// <param name="set1">The first set.</param>
/// <param name="set2">The second set.</param>
/// <returns>Returns a value indicating whether the box has been split.</returns>
private bool Cut(Box set1, Box set2)
{
double wholeR = WuColorQuantizer.Volume(set1, this.vmr);
double wholeG = WuColorQuantizer.Volume(set1, this.vmg);
double wholeB = WuColorQuantizer.Volume(set1, this.vmb);
double wholeW = WuColorQuantizer.Volume(set1, this.vwt);
int cutr;
int cutg;
int cutb;
double maxr = this.Maximize(set1, 2, set1.R0 + 1, set1.R1, out cutr, wholeR, wholeG, wholeB, wholeW);
double maxg = this.Maximize(set1, 1, set1.G0 + 1, set1.G1, out cutg, wholeR, wholeG, wholeB, wholeW);
double maxb = this.Maximize(set1, 0, set1.B0 + 1, set1.B1, out cutb, wholeR, wholeG, wholeB, wholeW);
int dir;
if ((maxr >= maxg) && (maxr >= maxb))
{
dir = 2;
if (cutr < 0)
{
return(false);
}
}
else if ((maxg >= maxr) && (maxg >= maxb))
{
dir = 1;
}
else
{
dir = 0;
}
set2.R1 = set1.R1;
set2.G1 = set1.G1;
set2.B1 = set1.B1;
switch (dir)
{
// Red
case 2:
set2.R0 = set1.R1 = cutr;
set2.G0 = set1.G0;
set2.B0 = set1.B0;
break;
// Green
case 1:
set2.G0 = set1.G1 = cutg;
set2.R0 = set1.R0;
set2.B0 = set1.B0;
break;
// Blue
case 0:
set2.B0 = set1.B1 = cutb;
set2.R0 = set1.R0;
set2.G0 = set1.G0;
break;
}
set1.Volume = (set1.R1 - set1.R0) * (set1.G1 - set1.G0) * (set1.B1 - set1.B0);
set2.Volume = (set2.R1 - set2.R0) * (set2.G1 - set2.G0) * (set2.B1 - set2.B0);
return(true);
}