/// <summary>
/// Splits this cube's color list at median index, and returns two newly created cubes.
/// </summary>
/// <param name="componentIndex">Index of the component (red = 0, green = 1, blue = 2).</param>
/// <param name="firstMedianCutCube">The first created cube.</param>
/// <param name="secondMedianCutCube">The second created cube.</param>
public void SplitAtMedian(Byte componentIndex, out MedianCutCube firstMedianCutCube, out MedianCutCube secondMedianCutCube)
{
List <Int32> colors;
switch (componentIndex)
{
// red colors
case 0:
colors = colorList.OrderBy(argb => ColorModelHelper.GetComponentA(ColorModel, Color.FromArgb(argb))).ToList();
break;
// green colors
case 1:
colors = colorList.OrderBy(argb => ColorModelHelper.GetComponentB(ColorModel, Color.FromArgb(argb))).ToList();
break;
// blue colors
case 2:
colors = colorList.OrderBy(argb => ColorModelHelper.GetComponentC(ColorModel, Color.FromArgb(argb))).ToList();
break;
default:
throw new NotSupportedException("Only three color components are supported (R, G and B).");
}
// retrieves the median index (a half point)
Int32 medianIndex = colorList.Count >> 1;
// creates the two half-cubes
firstMedianCutCube = new MedianCutCube(colors.GetRange(0, medianIndex));
secondMedianCutCube = new MedianCutCube(colors.GetRange(medianIndex, colors.Count - medianIndex));
}
/// <summary>
/// See <see cref="BaseColorCacheQuantizer.OnGetPaletteToCache"/> for more details.
/// </summary>
protected override List <Color> OnGetPaletteToCache(Int32 colorCount)
{
// creates the initial cube covering all the pixels in the image
MedianCutCube initalMedianCutCube = new MedianCutCube(UniqueColors.Keys);
cubeList.Add(initalMedianCutCube);
// finds the minimum iterations needed to achieve the cube count (color count) we need
Int32 iterationCount = 1;
while ((1 << iterationCount) < colorCount)
{
iterationCount++;
}
for (Int32 iteration = 0; iteration < iterationCount; iteration++)
{
SplitCubes(colorCount);
}
// initializes the result palette
List <Color> result = new List <Color>();
Int32 paletteIndex = 0;
// adds all the cubes' colors to the palette, and mark that cube with palette index for later use
foreach (MedianCutCube cube in cubeList)
{
result.Add(cube.Color);
cube.SetPaletteIndex(paletteIndex++);
}
// returns the palette (should contain <= ColorCount colors)
return(result);
}
