protected LookupData BuildLookups(IEnumerable<Box> cubes, ColorData data)
{
LookupData lookups = new LookupData(SideSize);
int lookupsCount = lookups.Lookups.Count;
foreach (var cube in cubes)
{
for (var alphaIndex = (byte)(cube.AlphaMinimum + 1); alphaIndex <= cube.AlphaMaximum; ++alphaIndex)
{
for (var redIndex = (byte)(cube.RedMinimum + 1); redIndex <= cube.RedMaximum; ++redIndex)
{
for (var greenIndex = (byte)(cube.GreenMinimum + 1); greenIndex <= cube.GreenMaximum; ++greenIndex)
{
for (var blueIndex = (byte)(cube.BlueMinimum + 1); blueIndex <= cube.BlueMaximum; ++blueIndex)
{
lookups.Tags[alphaIndex, redIndex, greenIndex, blueIndex] = lookupsCount;
}
}
}
}
var weight = Volume(cube, data.Weights);
if (weight <= 0) continue;
var lookup = new Lookup
{
Alpha = (int) (Volume(cube, data.MomentsAlpha)/weight),
Red = (int) (Volume(cube, data.MomentsRed)/weight),
Green = (int) (Volume(cube, data.MomentsGreen)/weight),
Blue = (int) (Volume(cube, data.MomentsBlue)/weight)
};
lookups.Lookups.Add(lookup);
}
return lookups;
}
protected override QuantizedPalette GetQuantizedPalette(int colorCount, ColorData data, IEnumerable <Box> cubes, int alphaThreshold)
{
int imageSize = data.PixelsCount;
LookupData lookups = BuildLookups(cubes, data);
IList <int> quantizedPixels = data.QuantizedPixels;
for (var index = 0; index < imageSize; ++index)
{
var indexParts = BitConverter.GetBytes(quantizedPixels[index]);
quantizedPixels[index] = lookups.Tags[indexParts[Alpha], indexParts[Red], indexParts[Green], indexParts[Blue]];
}
var alphas = new int[colorCount + 1];
var reds = new int[colorCount + 1];
var greens = new int[colorCount + 1];
var blues = new int[colorCount + 1];
var sums = new int[colorCount + 1];
var palette = new QuantizedPalette(imageSize);
IList <Pixel> pixels = data.Pixels;
int pixelsCount = data.PixelsCount;
IList <Lookup> lookupsList = lookups.Lookups;
int lookupsCount = lookupsList.Count;
Dictionary <int, int> cachedMaches = new Dictionary <int, int>();
for (int pixelIndex = 0; pixelIndex < pixelsCount; pixelIndex++)
{
Pixel pixel = pixels[pixelIndex];
palette.PixelIndex[pixelIndex] = -1;
if (pixel.Alpha <= alphaThreshold)
{
continue;
}
int bestMatch;
int argb = pixel.Argb;
if (!cachedMaches.TryGetValue(argb, out bestMatch))
{
int match = quantizedPixels[pixelIndex];
bestMatch = match;
int bestDistance = int.MaxValue;
for (int lookupIndex = 0; lookupIndex < lookupsCount; lookupIndex++)
{
Lookup lookup = lookupsList[lookupIndex];
var deltaAlpha = pixel.Alpha - lookup.Alpha;
var deltaRed = pixel.Red - lookup.Red;
var deltaGreen = pixel.Green - lookup.Green;
var deltaBlue = pixel.Blue - lookup.Blue;
int distance = deltaAlpha * deltaAlpha + deltaRed * deltaRed + deltaGreen * deltaGreen + deltaBlue * deltaBlue;
if (distance >= bestDistance)
{
continue;
}
bestDistance = distance;
bestMatch = lookupIndex;
}
cachedMaches[argb] = bestMatch;
}
alphas[bestMatch] += pixel.Alpha;
reds[bestMatch] += pixel.Red;
greens[bestMatch] += pixel.Green;
blues[bestMatch] += pixel.Blue;
sums[bestMatch]++;
palette.PixelIndex[pixelIndex] = bestMatch;
}
for (var paletteIndex = 0; paletteIndex < colorCount; paletteIndex++)
{
if (sums[paletteIndex] > 0)
{
alphas[paletteIndex] /= sums[paletteIndex];
reds[paletteIndex] /= sums[paletteIndex];
greens[paletteIndex] /= sums[paletteIndex];
blues[paletteIndex] /= sums[paletteIndex];
}
var color = Color.FromArgb(alphas[paletteIndex], reds[paletteIndex], greens[paletteIndex], blues[paletteIndex]);
palette.Colors.Add(color);
}
palette.Colors.Add(Color.FromArgb(0, 0, 0, 0));
return(palette);
}
