private static Difference[,] CalculateDistances(Color[][] palettes)
{
// Combination of each palette with each palette except with itself (diagonal)
Difference[,] distances = new Difference[palettes.Length, palettes.Length];
// Convert palettes to labcolor space to compute difference
LabColor[][] labPalettes = new LabColor[palettes.Length][];
for (int i = 0; i < palettes.Length; i++)
{
labPalettes[i] = ColorConversion.ToLabPalette <Color>(palettes[i]);
}
// Compute every possible difference
for (int i = 0; i < palettes.Length; i++)
{
for (int j = 0; j < palettes.Length; j++)
{
if (i == j)
{
continue;
}
distances[i, j] = new Difference();
distances[i, j].SrcPalette = i;
distances[i, j].DstPalette = j;
distances[i, j].Distance = PaletteDistance.CalculateDistance(
labPalettes[i], labPalettes[j]);
}
}
return(distances);
}
protected override Pixel QuantizatePixel(int x, int y)
{
// Get nearest color from palette
int colorIndex = nearestNeighbour.Search(labImg[y, x]);
// Apply dithering algorithm for each channel
LabColor oldPixel = labImg[y, x];
LabColor newPixel = labPalette[colorIndex];
this.Dithering.ApplyDithering(labImg.Data, x, y, 0, oldPixel.X - newPixel.X);
this.Dithering.ApplyDithering(labImg.Data, x, y, 1, oldPixel.Y - newPixel.Y);
this.Dithering.ApplyDithering(labImg.Data, x, y, 2, oldPixel.Z - newPixel.Z);
// If it's a transparent color, set the first palette color
Color rgbColor = this.rgbImg[y, x];
if (rgbColor.Alpha == 0)
{
return(new Pixel(0, 0, true));
}
else
{
return(new Pixel((uint)colorIndex, (uint)rgbColor.Alpha, true));
}
}
protected override Pixel QuantizatePixel(int x, int y)
{
// Get the color and add to the list
Color color = image[y, x];
int colorIndex;
if (listColor.Count < this.MaxColors)
{
if (!listColor.Contains(color))
{
listColor.Add(color);
}
colorIndex = listColor.IndexOf(color);
}
else
{
// Create the labpalette if so
if (nearestNeighbour == null)
{
LabColor[] labPalette = ColorConversion.ToLabPalette <Color>(listColor.ToArray());
nearestNeighbour = new ExhaustivePaletteSearch();
nearestNeighbour.Initialize(labPalette);
}
LabColor labNoTrans = ColorConversion.ToLabPalette <Color>(new Color[] { color })[0];
colorIndex = nearestNeighbour.Search(labNoTrans);
}
return(new Pixel((uint)colorIndex, (uint)color.Alpha, true));
}
public static double CalculateDistance(LabColor[] palette1, LabColor[] palette2)
{
double totalDistance = 0;
for (int i = 0; i < palette1.Length; i++) {
double minColorDistance = -1;
for (int j = 0; j < palette2.Length; j++) {
double distance = palette1[i].GetDistanceSquared(palette2[j]);
if (minColorDistance == -1 || distance < minColorDistance)
minColorDistance = distance;
}
totalDistance += minColorDistance;
}
return totalDistance;
}
public static double GetDistanceSquared(this LabColor c1, LabColor c2)
{
return (c2.X - c1.X) * (c2.X - c1.X) +
(c2.Y - c1.Y) * (c2.Y - c1.Y) +
(c2.Z - c1.Z) * (c2.Z - c1.Z);
}
/// <summary>
/// Gets the color difference using Delta E CIE76 (http://en.wikipedia.org/wiki/Color_difference)
/// </summary>
/// <returns>The distance.</returns>
/// <param name="c1">C1.</param>
/// <param name="c2">C2.</param>
public static double GetDistance(this LabColor c1, LabColor c2)
{
return Math.Sqrt(c1.GetDistanceSquared(c2));
}
public static double GetDistanceSquared(this LabColor c1, LabColor c2)
{
return((c2.X - c1.X) * (c2.X - c1.X) +
(c2.Y - c1.Y) * (c2.Y - c1.Y) +
(c2.Z - c1.Z) * (c2.Z - c1.Z));
}
/// <summary>
/// Gets the color difference using Delta E CIE76 (http://en.wikipedia.org/wiki/Color_difference)
/// </summary>
/// <returns>The distance.</returns>
/// <param name="c1">C1.</param>
/// <param name="c2">C2.</param>
public static double GetDistance(this LabColor c1, LabColor c2)
{
return(Math.Sqrt(c1.GetDistanceSquared(c2)));
}
private static Difference[,] CalculateDistances(Color[][] palettes)
{
// Combination of each palette with each palette except with itself (diagonal)
Difference[,] distances = new Difference[palettes.Length, palettes.Length];
// Convert palettes to labcolor space to compute difference
LabColor[][] labPalettes = new LabColor[palettes.Length][];
for (int i = 0; i < palettes.Length; i++)
labPalettes[i] = ColorConversion.ToLabPalette<Color>(palettes[i]);
// Compute every possible difference
for (int i = 0; i < palettes.Length; i++) {
for (int j = 0; j < palettes.Length; j++) {
if (i == j)
continue;
distances[i, j] = new Difference();
distances[i, j].SrcPalette = i;
distances[i, j].DstPalette = j;
distances[i, j].Distance = PaletteDistance.CalculateDistance(
labPalettes[i], labPalettes[j]);
}
}
return distances;
}
