private Dictionary <int, ColorData> GetMedianCutTable(List <ColorDataBox> boxes)
{
Dictionary <int, ColorData> medianCutTable = new Dictionary <int, ColorData>();
for (int i = 0; i < boxes.Count; i++)
{
ColorDataBox box = boxes[i];
int centerR = box.MinR + box.LengthR / 2;
int centerG = box.MinG + box.LengthG / 2;
int centerB = box.MinB + box.LengthB / 2;
medianCutTable.Add(i, new ColorData(centerR, centerG, centerB));
}
return(medianCutTable);
}
private List <ColorData>[] CountSort(ColorDataBox box, ColorChannel cc)
{
List <ColorData>[] colorTable = new List <ColorData> [256];
for (int i = 0; i < 256; i++)
{
colorTable[i] = new List <ColorData>();
}
for (int i = 0; i < box.ColorData.Length; i++)
{
ColorData data = box.ColorData[i];
colorTable[data.GetValue(cc)].Add(data);
}
return(colorTable);
}
private void GetImage(ImageData data, int bits)
{
int bitCount = (int)Math.Pow(2, bits);
List <ColorDataBox> boxes = new List <ColorDataBox>();
ColorData[] colors = new ColorData[data.RGBValues.Length / 3];
for (int i = 0; i < data.RGBValues.Length; i += 3)
{
colors[i / 3] = new ColorData(data.RGBValues[i + 2], data.RGBValues[i + 1], data.RGBValues[i]);
}
ColorDataBox totalBox = new ColorDataBox(colors);
boxes.Add(totalBox);
for (int i = 0; i < bitCount - 1; i++)
{
int index = GetLargestBox(boxes);
ColorDataBox box = boxes[index];
boxes.RemoveAt(index);
ColorChannel channel = ColorChannel.Red;
if (box.LengthR >= box.LengthG && box.LengthR >= box.LengthB)
{
channel = ColorChannel.Red;
}
else
{
if (box.LengthG >= box.LengthB)
{
channel = ColorChannel.Green;
}
else
{
channel = ColorChannel.Blue;
}
}
List <ColorData>[] colorTable = CountSort(box, channel);
List <ColorData> box1 = new List <ColorData>();
List <ColorData> box2 = new List <ColorData>();
int sum = 0;
int half = box.ColorData.Length / 2;
foreach (List <ColorData> colorData in colorTable)
{
if (sum < half)
{
if (sum + colorData.Count > half)
{
int diff = sum + colorData.Count - half;
box1.AddRange(colorData.GetRange(0, diff));
box2.AddRange(colorData.GetRange(diff, colorData.Count - diff));
}
else
{
box1.AddRange(colorData);
}
}
else
{
box2.AddRange(colorData);
}
sum += colorData.Count;
}
boxes.Add(new ColorDataBox(box1.ToArray()));
boxes.Add(new ColorDataBox(box2.ToArray()));
}
Dictionary <int, ColorData> medianCutTable = GetMedianCutTable(boxes);
int[,,] indexTable = new int[256, 256, 256];
for (int r = 0; r < 256; r++)
{
for (int g = 0; g < 256; g++)
{
for (int b = 0; b < 256; b++)
{
indexTable[r, g, b] = -1;
}
}
}
for (int i = 0; i < data.RGBValues.Length; i += 3)
{
ColorData colorData = colors[i / 3];
int index = indexTable[colorData.Red, colorData.Green, colorData.Blue];
if (index == -1)
{
index = GetContainingBox(colorData, boxes);
indexTable[colorData.Red, colorData.Green, colorData.Blue] = index;
}
ColorData newColor = medianCutTable[index];
data.RGBValues[i + 2] = (byte)newColor.Red;
data.RGBValues[i + 1] = (byte)newColor.Green;
data.RGBValues[i] = (byte)newColor.Blue;
}
}