/// <summary>
/// Computes the weighted variance of a box.
/// </summary>
/// <param name="c">The cube.</param>
/// <returns>The result.</returns>
private float Variance(ref Box c)
{
float dr = WuAlphaColorQuantizer.Volume(ref c, this.vmr);
float dg = WuAlphaColorQuantizer.Volume(ref c, this.vmg);
float db = WuAlphaColorQuantizer.Volume(ref c, this.vmb);
float da = WuAlphaColorQuantizer.Volume(ref c, this.vma);
float xx =
this.m2[WuAlphaColorQuantizer.GetIndex(c.R1, c.G1, c.B1, c.A1)]
- this.m2[WuAlphaColorQuantizer.GetIndex(c.R1, c.G1, c.B1, c.A0)]
- this.m2[WuAlphaColorQuantizer.GetIndex(c.R1, c.G1, c.B0, c.A1)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(c.R1, c.G1, c.B0, c.A0)]
- this.m2[WuAlphaColorQuantizer.GetIndex(c.R1, c.G0, c.B1, c.A1)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(c.R1, c.G0, c.B1, c.A0)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(c.R1, c.G0, c.B0, c.A1)]
- this.m2[WuAlphaColorQuantizer.GetIndex(c.R1, c.G0, c.B0, c.A0)]
- this.m2[WuAlphaColorQuantizer.GetIndex(c.R0, c.G1, c.B1, c.A1)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(c.R0, c.G1, c.B1, c.A0)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(c.R0, c.G1, c.B0, c.A1)]
- this.m2[WuAlphaColorQuantizer.GetIndex(c.R0, c.G1, c.B0, c.A0)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(c.R0, c.G0, c.B1, c.A1)]
- this.m2[WuAlphaColorQuantizer.GetIndex(c.R0, c.G0, c.B1, c.A0)]
- this.m2[WuAlphaColorQuantizer.GetIndex(c.R0, c.G0, c.B0, c.A1)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(c.R0, c.G0, c.B0, c.A0)];
return(xx - (((dr * dr) + (dg * dg) + (db * db) + (da * da)) / WuAlphaColorQuantizer.Volume(ref c, this.vwt)));
}
/// <summary>
/// Builds a 3-D color histogram of <c>counts, r/g/b, c^2</c>.
/// </summary>
/// <param name="image">The image.</param>
/// <param name="width">Width of image</param>
/// <param name="height">Height of image</param>
private unsafe void Build3DHistogram(uint *image, int width, int height)
{
int pixels = width * height;
for (int i = 0; i < pixels; i++)
{
uint pix = image[i];
int a = (int)((pix & 0xFF000000) >> 24);
int r = (int)((pix & 0x00FF0000) >> 16);
int g = (int)((pix & 0x0000FF00) >> 8);
int b = (int)(pix & 0x000000FF);
int inr = r >> (8 - WuAlphaColorQuantizer.IndexBits);
int ing = g >> (8 - WuAlphaColorQuantizer.IndexBits);
int inb = b >> (8 - WuAlphaColorQuantizer.IndexBits);
int ina = a >> (8 - WuAlphaColorQuantizer.IndexAlphaBits);
int ind = WuAlphaColorQuantizer.GetIndex((int)inr + 1, (int)ing + 1, (int)inb + 1, (int)ina + 1);
this.vwt[ind]++;
this.vmr[ind] += r;
this.vmg[ind] += g;
this.vmb[ind] += b;
this.vma[ind] += a;
this.m2[ind] += (r * r) + (g * g) + (b * b) + (a * a);
}
}
/// <summary>
/// Generates the quantized result.
/// </summary>
/// <param name="image">The image.</param>
/// <param name="colorCount">The color count.</param>
/// <param name="width">Width of image</param>
/// <param name="height">Height of image</param>
/// <param name="destPixels">Pixel values are written here. Must provide width*height memory.</param>
/// <param name="padMultiple4">True to write zero padding to make row bytes multiple of 4</param>
/// <returns>Receives colors</returns>
private unsafe uint[] GenerateResult(uint *image, int colorCount, int width, int height, byte *destPixels, bool padMultiple4)
{
uint[] palette = new uint[colorCount];
// rows must be a multiple of 4, hence padding up to 3 bytes for 8-bit indexed pixels
int widthMod4 = width % 4;
int widthZeros = widthMod4 != 0 ? 4 - widthMod4 : 0;
for (int k = 0; k < colorCount; k++)
{
this.Mark(ref this.cube[k], (byte)k);
float weight = WuAlphaColorQuantizer.Volume(ref this.cube[k], this.vwt);
if (weight != 0)
{
uint a = (byte)(WuAlphaColorQuantizer.Volume(ref this.cube[k], this.vma) / weight);
uint r = (byte)(WuAlphaColorQuantizer.Volume(ref this.cube[k], this.vmr) / weight);
uint g = (byte)(WuAlphaColorQuantizer.Volume(ref this.cube[k], this.vmg) / weight);
uint b = (byte)(WuAlphaColorQuantizer.Volume(ref this.cube[k], this.vmb) / weight);
palette[k] = (a << 24) | (r << 16) | (g << 8) | b;
}
else
{
palette[k] = 0xFF000000;
}
}
for (int ri = 0; ri < height; ri++)
{
for (int ci = 0; ci < width; ci++)
{
uint pix = image[0];
uint a = ((pix & 0xFF000000) >> 24) >> (8 - WuAlphaColorQuantizer.IndexAlphaBits);
uint r = ((pix & 0x00FF0000) >> 16) >> (8 - WuAlphaColorQuantizer.IndexBits);
uint g = ((pix & 0x0000FF00) >> 8) >> (8 - WuAlphaColorQuantizer.IndexBits);
uint b = (pix & 0x000000FF) >> (8 - WuAlphaColorQuantizer.IndexBits);
int ind = WuAlphaColorQuantizer.GetIndex((int)r + 1, (int)g + 1, (int)b + 1, (int)a + 1);
destPixels[0] = this.tag[ind];
destPixels++;
image++;
}
// write additional zero bytes if requested
if (padMultiple4)
{
for (int c = 0; c < widthZeros; c++)
{
destPixels[0] = 0x00;
destPixels++;
}
}
}
return(palette);
}
/// <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 = WuAlphaColorQuantizer.Volume(cube, this.vmr);
double dg = WuAlphaColorQuantizer.Volume(cube, this.vmg);
double db = WuAlphaColorQuantizer.Volume(cube, this.vmb);
double da = WuAlphaColorQuantizer.Volume(cube, this.vma);
double xx =
this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, cube.A1)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, cube.A0)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A1)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A0)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A1)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A0)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A1)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A0)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A1)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A0)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A1)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A0)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A1)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A0)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A1)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A0)];
return(xx - (((dr * dr) + (dg * dg) + (db * db) + (da * da)) / WuAlphaColorQuantizer.Volume(cube, this.vwt)));
}
private static int Top(ref Box cube, int direction, int position, int[] moment)
{
switch (direction)
{
// Red
case 3:
return(moment[WuAlphaColorQuantizer.GetIndex(position, cube.G1, cube.B1, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(position, cube.G1, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(position, cube.G1, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(position, cube.G1, cube.B0, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(position, cube.G0, cube.B1, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(position, cube.G0, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(position, cube.G0, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(position, cube.G0, cube.B0, cube.A0)]);
// Green
case 2:
return(moment[WuAlphaColorQuantizer.GetIndex(cube.R1, position, cube.B1, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, position, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, position, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, position, cube.B0, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, position, cube.B1, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, position, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, position, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, position, cube.B0, cube.A0)]);
// Blue
case 1:
return(moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, position, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, position, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, position, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, position, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, position, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, position, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, position, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, position, cube.A0)]);
// Alpha
case 0:
return(moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, position)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, position)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, position)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, position)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, position)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, position)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, position)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, position)]);
default:
throw new ArgumentOutOfRangeException("direction");
}
}
/// <summary>
/// Computes part of Volume(cube, moment) that doesn't depend on r1, g1, or b1 (depending on direction).
/// </summary>
/// <param name="cube">The cube.</param>
/// <param name="direction">The direction.</param>
/// <param name="moment">The moment.</param>
/// <returns>The result.</returns>
private static long Bottom(Box cube, int direction, long[] moment)
{
switch (direction)
{
// Red
case 3:
return(-moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A0)]);
// Green
case 2:
return(-moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A0)]);
// Blue
case 1:
return(-moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A0)]);
// Alpha
case 0:
return(-moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A0)]);
default:
throw new ArgumentOutOfRangeException(nameof(direction));
}
}
/// <summary>
/// We want to minimize the sum of the variances of two sub-boxes.
/// The sum(c^2) terms can be ignored since their sum over both sub-boxes
/// is the same (the sum for the whole box) no matter where we split.
/// The remaining terms have a minus sign in the variance formula,
/// so we drop the minus sign and maximize the sum of the two terms.
/// </summary>
/// <param name="c">The cube.</param>
/// <param name="direction">The direction.</param>
/// <param name="first">The first position.</param>
/// <param name="last">The last position.</param>
/// <param name="cut">The cutting point.</param>
/// <param name="wholeR">The whole red.</param>
/// <param name="wholeG">The whole green.</param>
/// <param name="wholeB">The whole blue.</param>
/// <param name="wholeA">The whole alpha.</param>
/// <param name="wholeW">The whole weight.</param>
/// <returns>The result.</returns>
private float Maximize(ref Box c, int direction, int first, int last, out int cut, float wholeR, float wholeG, float wholeB, float wholeA, float wholeW)
{
int baseR = Bottom(ref c, direction, this.vmr);
int baseG = WuAlphaColorQuantizer.Bottom(ref c, direction, this.vmg);
int baseB = WuAlphaColorQuantizer.Bottom(ref c, direction, this.vmb);
int baseA = WuAlphaColorQuantizer.Bottom(ref c, direction, this.vma);
int baseW = WuAlphaColorQuantizer.Bottom(ref c, direction, this.vwt);
float max = 0.0f;
cut = -1;
for (int i = first; i < last; i++)
{
float halfR = baseR + WuAlphaColorQuantizer.Top(ref c, direction, i, this.vmr);
float halfG = baseG + WuAlphaColorQuantizer.Top(ref c, direction, i, this.vmg);
float halfB = baseB + WuAlphaColorQuantizer.Top(ref c, direction, i, this.vmb);
float halfA = baseA + WuAlphaColorQuantizer.Top(ref c, direction, i, this.vma);
float halfW = baseW + WuAlphaColorQuantizer.Top(ref c, direction, i, this.vwt);
if (halfW == 0)
{
continue;
}
float temp = ((halfR * halfR) + (halfG * halfG) + (halfB * halfB) + (halfA * halfA)) / halfW;
halfR = wholeR - halfR;
halfG = wholeG - halfG;
halfB = wholeB - halfB;
halfA = wholeA - halfA;
halfW = wholeW - halfW;
if (halfW == 0)
{
continue;
}
temp += ((halfR * halfR) + (halfG * halfG) + (halfB * halfB) + (halfA * halfA)) / halfW;
if (temp > max)
{
max = temp;
cut = i;
}
}
return(max);
}
/// <summary>
/// We want to minimize the sum of the variances of two sub-boxes.
/// The sum(c^2) terms can be ignored since their sum over both sub-boxes
/// is the same (the sum for the whole box) no matter where we split.
/// The remaining terms have a minus sign in the variance formula,
/// so we drop the minus sign and maximize the sum of the two terms.
/// </summary>
/// <param name="cube">The cube.</param>
/// <param name="direction">The direction.</param>
/// <param name="first">The first position.</param>
/// <param name="last">The last position.</param>
/// <param name="cut">The cutting point.</param>
/// <param name="wholeR">The whole red.</param>
/// <param name="wholeG">The whole green.</param>
/// <param name="wholeB">The whole blue.</param>
/// <param name="wholeA">The whole alpha.</param>
/// <param name="wholeW">The whole weight.</param>
/// <returns>The result.</returns>
private double Maximize(Box cube, int direction, int first, int last, out int cut, double wholeR, double wholeG, double wholeB, double wholeA, double wholeW)
{
long baseR = WuAlphaColorQuantizer.Bottom(cube, direction, this.vmr);
long baseG = WuAlphaColorQuantizer.Bottom(cube, direction, this.vmg);
long baseB = WuAlphaColorQuantizer.Bottom(cube, direction, this.vmb);
long baseA = WuAlphaColorQuantizer.Bottom(cube, direction, this.vma);
long baseW = WuAlphaColorQuantizer.Bottom(cube, direction, this.vwt);
double max = 0.0;
cut = -1;
for (int i = first; i < last; i++)
{
double halfR = baseR + WuAlphaColorQuantizer.Top(cube, direction, i, this.vmr);
double halfG = baseG + WuAlphaColorQuantizer.Top(cube, direction, i, this.vmg);
double halfB = baseB + WuAlphaColorQuantizer.Top(cube, direction, i, this.vmb);
double halfA = baseA + WuAlphaColorQuantizer.Top(cube, direction, i, this.vma);
double halfW = baseW + WuAlphaColorQuantizer.Top(cube, direction, i, this.vwt);
if (halfW == 0)
{
continue;
}
double temp = ((halfR * halfR) + (halfG * halfG) + (halfB * halfB) + (halfA * halfA)) / halfW;
halfR = wholeR - halfR;
halfG = wholeG - halfG;
halfB = wholeB - halfB;
halfA = wholeA - halfA;
halfW = wholeW - halfW;
if (halfW == 0)
{
continue;
}
temp += ((halfR * halfR) + (halfG * halfG) + (halfB * halfB) + (halfA * halfA)) / halfW;
if (temp > max)
{
max = temp;
cut = i;
}
}
return(max);
}
/// <summary>
/// Marks a color space tag.
/// </summary>
/// <param name="c">The cube.</param>
/// <param name="label">A label.</param>
private void Mark(ref Box c, byte label)
{
for (int r = c.R0 + 1; r <= c.R1; r++)
{
for (int g = c.G0 + 1; g <= c.G1; g++)
{
for (int b = c.B0 + 1; b <= c.B1; b++)
{
for (int a = c.A0 + 1; a <= c.A1; a++)
{
this.tag[WuAlphaColorQuantizer.GetIndex(r, g, b, a)] = label;
}
}
}
}
}
private static float Volume(ref Box cube, int[] moment)
{
return((float)(moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A0)]));
}
/// <summary>
/// Computes sum over a box of any given statistic.
/// </summary>
/// <param name="cube">The cube.</param>
/// <param name="moment">The moment.</param>
/// <returns>The result.</returns>
private static double Volume(Box cube, long[] moment)
{
return(moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A0)]);
}
/// <summary>
/// Generates the quantized result.
/// </summary>
/// <param name="image">The image.</param>
/// <param name="colorCount">The color count.</param>
/// <returns>The result.</returns>
private ColorQuantizerResult GenerateResult(byte[] image, int colorCount)
{
var quantizedImage = new ColorQuantizerResult(image.Length / 4, colorCount);
for (int k = 0; k < colorCount; k++)
{
this.Mark(ref this.cube[k], (byte)k);
float weight = WuAlphaColorQuantizer.Volume(ref this.cube[k], this.vwt);
if (weight != 0)
{
quantizedImage.Palette[(k * 4) + 3] = (byte)(WuAlphaColorQuantizer.Volume(ref this.cube[k], this.vma) / weight);
quantizedImage.Palette[(k * 4) + 2] = (byte)(WuAlphaColorQuantizer.Volume(ref this.cube[k], this.vmr) / weight);
quantizedImage.Palette[(k * 4) + 1] = (byte)(WuAlphaColorQuantizer.Volume(ref this.cube[k], this.vmg) / weight);
quantizedImage.Palette[k * 4] = (byte)(WuAlphaColorQuantizer.Volume(ref this.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 a = image[(i * 4) + 3] >> (8 - WuAlphaColorQuantizer.IndexAlphaBits);
int r = image[(i * 4) + 2] >> (8 - WuAlphaColorQuantizer.IndexBits);
int g = image[(i * 4) + 1] >> (8 - WuAlphaColorQuantizer.IndexBits);
int b = image[i * 4] >> (8 - WuAlphaColorQuantizer.IndexBits);
int ind = WuAlphaColorQuantizer.GetIndex(r + 1, g + 1, b + 1, a + 1);
quantizedImage.Bytes[i] = this.tag[ind];
}
return(quantizedImage);
}
/// <summary>
/// Builds a 3-D color histogram of <c>counts, r/g/b, c^2</c>.
/// </summary>
/// <param name="image">The image.</param>
private void Build3DHistogram(byte[] image)
{
for (int i = 0; i < image.Length; i += 4)
{
int a = image[i + 3];
int r = image[i + 2];
int g = image[i + 1];
int b = image[i];
int inr = r >> (8 - WuAlphaColorQuantizer.IndexBits);
int ing = g >> (8 - WuAlphaColorQuantizer.IndexBits);
int inb = b >> (8 - WuAlphaColorQuantizer.IndexBits);
int ina = a >> (8 - WuAlphaColorQuantizer.IndexAlphaBits);
int ind = WuAlphaColorQuantizer.GetIndex(inr + 1, ing + 1, inb + 1, ina + 1);
this.vwt[ind]++;
this.vmr[ind] += r;
this.vmg[ind] += g;
this.vmb[ind] += b;
this.vma[ind] += a;
this.m2[ind] += (r * r) + (g * g) + (b * b) + (a * a);
}
}
/// <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(ref Box set1, ref Box set2)
{
float wholeR = WuAlphaColorQuantizer.Volume(ref set1, this.vmr);
float wholeG = WuAlphaColorQuantizer.Volume(ref set1, this.vmg);
float wholeB = WuAlphaColorQuantizer.Volume(ref set1, this.vmb);
float wholeA = WuAlphaColorQuantizer.Volume(ref set1, this.vma);
float wholeW = WuAlphaColorQuantizer.Volume(ref set1, this.vwt);
int cutr;
int cutg;
int cutb;
int cuta;
float maxr = this.Maximize(ref set1, 3, set1.R0 + 1, set1.R1, out cutr, wholeR, wholeG, wholeB, wholeA, wholeW);
float maxg = this.Maximize(ref set1, 2, set1.G0 + 1, set1.G1, out cutg, wholeR, wholeG, wholeB, wholeA, wholeW);
float maxb = this.Maximize(ref set1, 1, set1.B0 + 1, set1.B1, out cutb, wholeR, wholeG, wholeB, wholeA, wholeW);
float maxa = this.Maximize(ref set1, 0, set1.A0 + 1, set1.A1, out cuta, wholeR, wholeG, wholeB, wholeA, wholeW);
int dir;
if ((maxr >= maxg) && (maxr >= maxb) && (maxr >= maxa))
{
dir = 3;
if (cutr < 0)
{
return(false);
}
}
else if ((maxg >= maxr) && (maxg >= maxb) && (maxg >= maxa))
{
dir = 2;
}
else if ((maxb >= maxr) && (maxb >= maxg) && (maxb >= maxa))
{
dir = 1;
}
else
{
dir = 0;
}
set2.R1 = set1.R1;
set2.G1 = set1.G1;
set2.B1 = set1.B1;
set2.A1 = set1.A1;
switch (dir)
{
// Red
case 3:
set2.R0 = set1.R1 = cutr;
set2.G0 = set1.G0;
set2.B0 = set1.B0;
set2.A0 = set1.A0;
break;
// Green
case 2:
set2.G0 = set1.G1 = cutg;
set2.R0 = set1.R0;
set2.B0 = set1.B0;
set2.A0 = set1.A0;
break;
// Blue
case 1:
set2.B0 = set1.B1 = cutb;
set2.R0 = set1.R0;
set2.G0 = set1.G0;
set2.A0 = set1.A0;
break;
// Alpha
case 0:
set2.A0 = set1.A1 = cuta;
set2.R0 = set1.R0;
set2.G0 = set1.G0;
set2.B0 = set1.B0;
break;
}
set1.Volume = (set1.R1 - set1.R0) * (set1.G1 - set1.G0) * (set1.B1 - set1.B0) * (set1.A1 - set1.A0);
set2.Volume = (set2.R1 - set2.R0) * (set2.G1 - set2.G0) * (set2.B1 - set2.B0) * (set2.A1 - set2.A0);
return(true);
}
/// <summary>
/// Converts the histogram into moments so that we can rapidly calculate
/// the sums of the above quantities over any desired box.
/// </summary>
private void Get3DMoments()
{
for (int r = 1; r < WuAlphaColorQuantizer.IndexCount; r++)
{
Array.Clear(this.volume, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(this.volumeR, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(this.volumeG, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(this.volumeB, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(this.volumeA, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(this.volume2, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
for (int g = 1; g < WuAlphaColorQuantizer.IndexCount; g++)
{
Array.Clear(this.area, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(this.areaR, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(this.areaG, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(this.areaB, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(this.areaA, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(this.area2, 0, WuAlphaColorQuantizer.IndexAlphaCount);
for (int b = 1; b < WuAlphaColorQuantizer.IndexCount; b++)
{
int line = 0;
int lineR = 0;
int lineG = 0;
int lineB = 0;
int lineA = 0;
float line2 = 0;
for (int a = 1; a < WuAlphaColorQuantizer.IndexAlphaCount; a++)
{
int ind1 = WuAlphaColorQuantizer.GetIndex(r, g, b, a);
line += this.vwt[ind1];
lineR += this.vmr[ind1];
lineG += this.vmg[ind1];
lineB += this.vmb[ind1];
lineA += this.vma[ind1];
line2 += this.m2[ind1];
this.area[a] += line;
this.areaR[a] += lineR;
this.areaG[a] += lineG;
this.areaB[a] += lineB;
this.areaA[a] += lineA;
this.area2[a] += line2;
int inv = (b * WuAlphaColorQuantizer.IndexAlphaCount) + a;
this.volume[inv] += this.area[a];
this.volumeR[inv] += this.areaR[a];
this.volumeG[inv] += this.areaG[a];
this.volumeB[inv] += this.areaB[a];
this.volumeA[inv] += this.areaA[a];
this.volume2[inv] += this.area2[a];
int ind2 = ind1 - WuAlphaColorQuantizer.GetIndex(1, 0, 0, 0);
this.vwt[ind1] = this.vwt[ind2] + this.volume[inv];
this.vmr[ind1] = this.vmr[ind2] + this.volumeR[inv];
this.vmg[ind1] = this.vmg[ind2] + this.volumeG[inv];
this.vmb[ind1] = this.vmb[ind2] + this.volumeB[inv];
this.vma[ind1] = this.vma[ind2] + this.volumeA[inv];
this.m2[ind1] = this.m2[ind2] + this.volume2[inv];
}
}
}
}
}
/// <summary>
/// Converts the histogram into moments so that we can rapidly calculate
/// the sums of the above quantities over any desired box.
/// </summary>
private void Get3DMoments()
{
long[] volume = new long[WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount];
long[] volumeR = new long[WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount];
long[] volumeG = new long[WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount];
long[] volumeB = new long[WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount];
long[] volumeA = new long[WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount];
double[] volume2 = new double[WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount];
long[] area = new long[WuAlphaColorQuantizer.IndexAlphaCount];
long[] areaR = new long[WuAlphaColorQuantizer.IndexAlphaCount];
long[] areaG = new long[WuAlphaColorQuantizer.IndexAlphaCount];
long[] areaB = new long[WuAlphaColorQuantizer.IndexAlphaCount];
long[] areaA = new long[WuAlphaColorQuantizer.IndexAlphaCount];
double[] area2 = new double[WuAlphaColorQuantizer.IndexAlphaCount];
for (int r = 1; r < WuAlphaColorQuantizer.IndexCount; r++)
{
Array.Clear(volume, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(volumeR, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(volumeG, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(volumeB, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(volumeA, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(volume2, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
for (int g = 1; g < WuAlphaColorQuantizer.IndexCount; g++)
{
Array.Clear(area, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(areaR, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(areaG, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(areaB, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(areaA, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(area2, 0, WuAlphaColorQuantizer.IndexAlphaCount);
for (int b = 1; b < WuAlphaColorQuantizer.IndexCount; b++)
{
long line = 0;
long lineR = 0;
long lineG = 0;
long lineB = 0;
long lineA = 0;
double line2 = 0;
for (int a = 1; a < WuAlphaColorQuantizer.IndexAlphaCount; a++)
{
int ind1 = WuAlphaColorQuantizer.GetIndex(r, g, b, a);
line += this.vwt[ind1];
lineR += this.vmr[ind1];
lineG += this.vmg[ind1];
lineB += this.vmb[ind1];
lineA += this.vma[ind1];
line2 += this.m2[ind1];
area[a] += line;
areaR[a] += lineR;
areaG[a] += lineG;
areaB[a] += lineB;
areaA[a] += lineA;
area2[a] += line2;
int inv = (b * WuAlphaColorQuantizer.IndexAlphaCount) + a;
volume[inv] += area[a];
volumeR[inv] += areaR[a];
volumeG[inv] += areaG[a];
volumeB[inv] += areaB[a];
volumeA[inv] += areaA[a];
volume2[inv] += area2[a];
int ind2 = ind1 - WuAlphaColorQuantizer.GetIndex(1, 0, 0, 0);
this.vwt[ind1] = this.vwt[ind2] + volume[inv];
this.vmr[ind1] = this.vmr[ind2] + volumeR[inv];
this.vmg[ind1] = this.vmg[ind2] + volumeG[inv];
this.vmb[ind1] = this.vmb[ind2] + volumeB[inv];
this.vma[ind1] = this.vma[ind2] + volumeA[inv];
this.m2[ind1] = this.m2[ind2] + volume2[inv];
}
}
}
}
}