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Merge pull request #393 from SixLabors/js/wu-quantizer 

Fix WuQuantizer output + optimizations
af/merge-core
James Jackson-South 8 years ago
committed by GitHub
parent
96b997e335 1d99117844
commit
794aac8ff1
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2 changed files with 92 additions and 91 deletions
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  1. 5
      src/ImageSharp/Quantizers/Box.cs
  2. 178
      src/ImageSharp/Quantizers/WuQuantizer{TPixel}.cs

5
src/ImageSharp/Quantizers/Box.cs
View File

@ -5,9 +5,8 @@ namespace SixLabors.ImageSharp.Quantizers
{
/// <summary>
/// Represents a box color cube.
/// TODO: This should be a struct for performance
/// </summary>
internal sealed class Box
internal struct Box
{
/// <summary>
/// Gets or sets the min red value, exclusive.
@ -54,4 +53,4 @@ namespace SixLabors.ImageSharp.Quantizers
/// </summary>
public int Volume { get; set; }
}
}
}

178
src/ImageSharp/Quantizers/WuQuantizer{TPixel}.cs
View File

@ -168,20 +168,19 @@ namespace SixLabors.ImageSharp.Quantizers
this.palette = new TPixel[this.colors];
for (int k = 0; k < this.colors; k++)
{
this.Mark(this.colorCube[k], (byte)k);
this.Mark(ref this.colorCube[k], (byte)k);
float weight = Volume(this.colorCube[k], this.vwt);
float weight = Volume(ref this.colorCube[k], this.vwt);
if (MathF.Abs(weight) > Constants.Epsilon)
{
float r = Volume(this.colorCube[k], this.vmr) / weight;
float g = Volume(this.colorCube[k], this.vmg) / weight;
float b = Volume(this.colorCube[k], this.vmb) / weight;
float a = Volume(this.colorCube[k], this.vma) / weight;
var color = default(TPixel);
color.PackFromVector4(new Vector4(r, g, b, a) / 255F);
this.palette[k] = color;
float r = Volume(ref this.colorCube[k], this.vmr);
float g = Volume(ref this.colorCube[k], this.vmg);
float b = Volume(ref this.colorCube[k], this.vmb);
float a = Volume(ref this.colorCube[k], this.vma);
ref TPixel color = ref this.palette[k];
color.PackFromVector4(new Vector4(r, g, b, a) / weight / 255F);
}
}
}
@ -197,19 +196,21 @@ namespace SixLabors.ImageSharp.Quantizers
var rgba = default(Rgba32);
pixel.ToRgba32(ref rgba);
int r = rgba.R >> 2; // 8 - IndexBits
int g = rgba.G >> 2;
int b = rgba.B >> 2;
int a = rgba.A >> 5; // 8 - IndexAlphaBits
int r = rgba.R >> (8 - IndexBits);
int g = rgba.G >> (8 - IndexBits);
int b = rgba.B >> (8 - IndexBits);
int a = rgba.A >> (8 - IndexAlphaBits);
int index = GetPaletteIndex(r + 1, g + 1, b + 1, a + 1);
int ind = GetPaletteIndex(r + 1, g + 1, b + 1, a + 1);
this.vwt[index]++;
this.vmr[index] += rgba.R;
this.vmg[index] += rgba.G;
this.vmb[index] += rgba.B;
this.vma[index] += rgba.A;
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);
var vector = new Vector4(rgba.R, rgba.G, rgba.B, rgba.A);
this.m2[index] += Vector4.Dot(vector, vector);
}
/// <inheritdoc/>
@ -301,7 +302,7 @@ namespace SixLabors.ImageSharp.Quantizers
/// <param name="cube">The cube.</param>
/// <param name="moment">The moment.</param>
/// <returns>The result.</returns>
private static float Volume(Box cube, long[] moment)
private static float Volume(ref Box cube, long[] moment)
{
return moment[GetPaletteIndex(cube.R1, cube.G1, cube.B1, cube.A1)]
- moment[GetPaletteIndex(cube.R1, cube.G1, cube.B1, cube.A0)]
@ -328,12 +329,12 @@ namespace SixLabors.ImageSharp.Quantizers
/// <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)
private static long Bottom(ref Box cube, int direction, long[] moment)
{
switch (direction)
{
// Red
case 0:
case 3:
return -moment[GetPaletteIndex(cube.R0, cube.G1, cube.B1, cube.A1)]
+ moment[GetPaletteIndex(cube.R0, cube.G1, cube.B1, cube.A0)]
+ moment[GetPaletteIndex(cube.R0, cube.G1, cube.B0, cube.A1)]
@ -344,7 +345,7 @@ namespace SixLabors.ImageSharp.Quantizers
+ moment[GetPaletteIndex(cube.R0, cube.G0, cube.B0, cube.A0)];
// Green
case 1:
case 2:
return -moment[GetPaletteIndex(cube.R1, cube.G0, cube.B1, cube.A1)]
+ moment[GetPaletteIndex(cube.R1, cube.G0, cube.B1, cube.A0)]
+ moment[GetPaletteIndex(cube.R1, cube.G0, cube.B0, cube.A1)]
@ -355,7 +356,7 @@ namespace SixLabors.ImageSharp.Quantizers
+ moment[GetPaletteIndex(cube.R0, cube.G0, cube.B0, cube.A0)];
// Blue
case 2:
case 1:
return -moment[GetPaletteIndex(cube.R1, cube.G1, cube.B0, cube.A1)]
+ moment[GetPaletteIndex(cube.R1, cube.G1, cube.B0, cube.A0)]
+ moment[GetPaletteIndex(cube.R1, cube.G0, cube.B0, cube.A1)]
@ -366,7 +367,7 @@ namespace SixLabors.ImageSharp.Quantizers
+ moment[GetPaletteIndex(cube.R0, cube.G0, cube.B0, cube.A0)];
// Alpha
case 3:
case 0:
return -moment[GetPaletteIndex(cube.R1, cube.G1, cube.B1, cube.A0)]
+ moment[GetPaletteIndex(cube.R1, cube.G1, cube.B0, cube.A0)]
+ moment[GetPaletteIndex(cube.R1, cube.G0, cube.B1, cube.A0)]
@ -389,12 +390,12 @@ namespace SixLabors.ImageSharp.Quantizers
/// <param name="position">The position.</param>
/// <param name="moment">The moment.</param>
/// <returns>The result.</returns>
private static long Top(Box cube, int direction, int position, long[] moment)
private static long Top(ref Box cube, int direction, int position, long[] moment)
{
switch (direction)
{
// Red
case 0:
case 3:
return moment[GetPaletteIndex(position, cube.G1, cube.B1, cube.A1)]
- moment[GetPaletteIndex(position, cube.G1, cube.B1, cube.A0)]
- moment[GetPaletteIndex(position, cube.G1, cube.B0, cube.A1)]
@ -405,7 +406,7 @@ namespace SixLabors.ImageSharp.Quantizers
- moment[GetPaletteIndex(position, cube.G0, cube.B0, cube.A0)];
// Green
case 1:
case 2:
return moment[GetPaletteIndex(cube.R1, position, cube.B1, cube.A1)]
- moment[GetPaletteIndex(cube.R1, position, cube.B1, cube.A0)]
- moment[GetPaletteIndex(cube.R1, position, cube.B0, cube.A1)]
@ -416,7 +417,7 @@ namespace SixLabors.ImageSharp.Quantizers
- moment[GetPaletteIndex(cube.R0, position, cube.B0, cube.A0)];
// Blue
case 2:
case 1:
return moment[GetPaletteIndex(cube.R1, cube.G1, position, cube.A1)]
- moment[GetPaletteIndex(cube.R1, cube.G1, position, cube.A0)]
- moment[GetPaletteIndex(cube.R1, cube.G0, position, cube.A1)]
@ -427,7 +428,7 @@ namespace SixLabors.ImageSharp.Quantizers
- moment[GetPaletteIndex(cube.R0, cube.G0, position, cube.A0)];
// Alpha
case 3:
case 0:
return moment[GetPaletteIndex(cube.R1, cube.G1, cube.B1, position)]
- moment[GetPaletteIndex(cube.R1, cube.G1, cube.B0, position)]
- moment[GetPaletteIndex(cube.R1, cube.G0, cube.B1, position)]
@ -553,12 +554,12 @@ namespace SixLabors.ImageSharp.Quantizers
/// </summary>
/// <param name="cube">The cube.</param>
/// <returns>The <see cref="float"/>.</returns>
private float Variance(Box cube)
private float Variance(ref Box cube)
{
float dr = Volume(cube, this.vmr);
float dg = Volume(cube, this.vmg);
float db = Volume(cube, this.vmb);
float da = Volume(cube, this.vma);
float dr = Volume(ref cube, this.vmr);
float dg = Volume(ref cube, this.vmg);
float db = Volume(ref cube, this.vmb);
float da = Volume(ref cube, this.vma);
float xx =
this.m2[GetPaletteIndex(cube.R1, cube.G1, cube.B1, cube.A1)]
@ -578,7 +579,8 @@ namespace SixLabors.ImageSharp.Quantizers
- this.m2[GetPaletteIndex(cube.R0, cube.G0, cube.B0, cube.A1)]
+ this.m2[GetPaletteIndex(cube.R0, cube.G0, cube.B0, cube.A0)];
return xx - (((dr * dr) + (dg * dg) + (db * db) + (da * da)) / Volume(cube, this.vwt));
var vector = new Vector4(dr, dg, db, da);
return xx - (Vector4.Dot(vector, vector) / Volume(ref cube, this.vwt));
}
/// <summary>
@ -599,38 +601,33 @@ namespace SixLabors.ImageSharp.Quantizers
/// <param name="wholeA">The whole alpha.</param>
/// <param name="wholeW">The whole weight.</param>
/// <returns>The <see cref="float"/>.</returns>
private float Maximize(Box cube, int direction, int first, int last, out int cut, float wholeR, float wholeG, float wholeB, float wholeA, float wholeW)
private float Maximize(ref Box cube, int direction, int first, int last, out int cut, float wholeR, float wholeG, float wholeB, float wholeA, float wholeW)
{
long baseR = Bottom(cube, direction, this.vmr);
long baseG = Bottom(cube, direction, this.vmg);
long baseB = Bottom(cube, direction, this.vmb);
long baseA = Bottom(cube, direction, this.vma);
long baseW = Bottom(cube, direction, this.vwt);
long baseR = Bottom(ref cube, direction, this.vmr);
long baseG = Bottom(ref cube, direction, this.vmg);
long baseB = Bottom(ref cube, direction, this.vmb);
long baseA = Bottom(ref cube, direction, this.vma);
long baseW = Bottom(ref cube, direction, this.vwt);
float max = 0F;
cut = -1;
for (int i = first; i < last; i++)
{
float halfR = baseR + Top(cube, direction, i, this.vmr);
float halfG = baseG + Top(cube, direction, i, this.vmg);
float halfB = baseB + Top(cube, direction, i, this.vmb);
float halfA = baseA + Top(cube, direction, i, this.vma);
float halfW = baseW + Top(cube, direction, i, this.vwt);
float temp;
float halfR = baseR + Top(ref cube, direction, i, this.vmr);
float halfG = baseG + Top(ref cube, direction, i, this.vmg);
float halfB = baseB + Top(ref cube, direction, i, this.vmb);
float halfA = baseA + Top(ref cube, direction, i, this.vma);
float halfW = baseW + Top(ref cube, direction, i, this.vwt);
if (MathF.Abs(halfW) < Constants.Epsilon)
{
continue;
}
temp = ((halfR * halfR) + (halfG * halfG) + (halfB * halfB) + (halfA * halfA)) / halfW;
var vector = new Vector4(halfR, halfG, halfB, halfA);
float temp = Vector4.Dot(vector, vector) / halfW;
halfR = wholeR - halfR;
halfG = wholeG - halfG;
halfB = wholeB - halfB;
halfA = wholeA - halfA;
halfW = wholeW - halfW;
if (MathF.Abs(halfW) < Constants.Epsilon)
@ -638,7 +635,14 @@ namespace SixLabors.ImageSharp.Quantizers
continue;
}
temp += ((halfR * halfR) + (halfG * halfG) + (halfB * halfB) + (halfA * halfA)) / halfW;
halfR = wholeR - halfR;
halfG = wholeG - halfG;
halfB = wholeB - halfB;
halfA = wholeA - halfA;
vector = new Vector4(halfR, halfG, halfB, halfA);
temp += Vector4.Dot(vector, vector) / halfW;
if (temp > max)
{
@ -656,24 +660,24 @@ namespace SixLabors.ImageSharp.Quantizers
/// <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)
private bool Cut(ref Box set1, ref Box set2)
{
float wholeR = Volume(set1, this.vmr);
float wholeG = Volume(set1, this.vmg);
float wholeB = Volume(set1, this.vmb);
float wholeA = Volume(set1, this.vma);
float wholeW = Volume(set1, this.vwt);
float wholeR = Volume(ref set1, this.vmr);
float wholeG = Volume(ref set1, this.vmg);
float wholeB = Volume(ref set1, this.vmb);
float wholeA = Volume(ref set1, this.vma);
float wholeW = Volume(ref set1, this.vwt);
float maxr = this.Maximize(set1, 0, set1.R0 + 1, set1.R1, out int cutr, wholeR, wholeG, wholeB, wholeA, wholeW);
float maxg = this.Maximize(set1, 1, set1.G0 + 1, set1.G1, out int cutg, wholeR, wholeG, wholeB, wholeA, wholeW);
float maxb = this.Maximize(set1, 2, set1.B0 + 1, set1.B1, out int cutb, wholeR, wholeG, wholeB, wholeA, wholeW);
float maxa = this.Maximize(set1, 3, set1.A0 + 1, set1.A1, out int cuta, wholeR, wholeG, wholeB, wholeA, wholeW);
float maxr = this.Maximize(ref set1, 3, set1.R0 + 1, set1.R1, out int cutr, wholeR, wholeG, wholeB, wholeA, wholeW);
float maxg = this.Maximize(ref set1, 2, set1.G0 + 1, set1.G1, out int cutg, wholeR, wholeG, wholeB, wholeA, wholeW);
float maxb = this.Maximize(ref set1, 1, set1.B0 + 1, set1.B1, out int cutb, wholeR, wholeG, wholeB, wholeA, wholeW);
float maxa = this.Maximize(ref set1, 0, set1.A0 + 1, set1.A1, out int cuta, wholeR, wholeG, wholeB, wholeA, wholeW);
int dir;
if ((maxr >= maxg) && (maxr >= maxb) && (maxr >= maxa))
{
dir = 0;
dir = 3;
if (cutr < 0)
{
@ -682,15 +686,15 @@ namespace SixLabors.ImageSharp.Quantizers
}
else if ((maxg >= maxr) && (maxg >= maxb) && (maxg >= maxa))
{
dir = 1;
dir = 2;
}
else if ((maxb >= maxr) && (maxb >= maxg) && (maxb >= maxa))
{
dir = 2;
dir = 1;
}
else
{
dir = 3;
dir = 0;
}
set2.R1 = set1.R1;
@ -701,7 +705,7 @@ namespace SixLabors.ImageSharp.Quantizers
switch (dir)
{
// Red
case 0:
case 3:
set2.R0 = set1.R1 = cutr;
set2.G0 = set1.G0;
set2.B0 = set1.B0;
@ -709,7 +713,7 @@ namespace SixLabors.ImageSharp.Quantizers
break;
// Green
case 1:
case 2:
set2.G0 = set1.G1 = cutg;
set2.R0 = set1.R0;
set2.B0 = set1.B0;
@ -717,7 +721,7 @@ namespace SixLabors.ImageSharp.Quantizers
break;
// Blue
case 2:
case 1:
set2.B0 = set1.B1 = cutb;
set2.R0 = set1.R0;
set2.G0 = set1.G0;
@ -725,7 +729,7 @@ namespace SixLabors.ImageSharp.Quantizers
break;
// Alpha
case 3:
case 0:
set2.A0 = set1.A1 = cuta;
set2.R0 = set1.R0;
set2.G0 = set1.G0;
@ -744,7 +748,7 @@ namespace SixLabors.ImageSharp.Quantizers
/// </summary>
/// <param name="cube">The cube.</param>
/// <param name="label">A label.</param>
private void Mark(Box cube, byte label)
private void Mark(ref Box cube, byte label)
{
for (int r = cube.R0 + 1; r <= cube.R1; r++)
{
@ -769,23 +773,21 @@ namespace SixLabors.ImageSharp.Quantizers
this.colorCube = new Box[this.colors];
float[] vv = new float[this.colors];
for (int i = 0; i < this.colors; i++)
{
this.colorCube[i] = new Box();
}
this.colorCube[0].R0 = this.colorCube[0].G0 = this.colorCube[0].B0 = this.colorCube[0].A0 = 0;
this.colorCube[0].R1 = this.colorCube[0].G1 = this.colorCube[0].B1 = IndexCount - 1;
this.colorCube[0].A1 = IndexAlphaCount - 1;
ref var cube = ref this.colorCube[0];
cube.R0 = cube.G0 = cube.B0 = cube.A0 = 0;
cube.R1 = cube.G1 = cube.B1 = IndexCount - 1;
cube.A1 = IndexAlphaCount - 1;
int next = 0;
for (int i = 1; i < this.colors; i++)
{
if (this.Cut(this.colorCube[next], this.colorCube[i]))
ref var nextCube = ref this.colorCube[next];
ref var currentCube = ref this.colorCube[i];
if (this.Cut(ref nextCube, ref currentCube))
{
vv[next] = this.colorCube[next].Volume > 1 ? this.Variance(this.colorCube[next]) : 0F;
vv[i] = this.colorCube[i].Volume > 1 ? this.Variance(this.colorCube[i]) : 0F;
vv[next] = nextCube.Volume > 1 ? this.Variance(ref nextCube) : 0F;
vv[i] = currentCube.Volume > 1 ? this.Variance(ref currentCube) : 0F;
}
else
{
@ -805,7 +807,7 @@ namespace SixLabors.ImageSharp.Quantizers
}
}
if (temp <= 0.0)
if (temp <= 0F)
{
this.colors = i + 1;
break;

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