public static void InsertIntoSortedList(List <ColorQuantizationBox> list, ColorQuantizationBox newItem, Func <ColorQuantizationBox, long> sortPriority)
{
if (list.Count == 0)
{
list.Add(newItem);
return;
}
long newItemPriority = sortPriority(newItem);
if (newItemPriority < sortPriority(list[0]))
{
list.Insert(0, newItem);
return;
}
if (newItemPriority > sortPriority(list.Last()))
{
list.Add(newItem);
return;
}
int newIndex = 0;
for (int i = 0; i < list.Count; i++)
{
if (newItemPriority <= sortPriority(list[i]))
{
newIndex = i;
break;
}
}
list.Insert(newIndex, newItem);
}
public ColorQuantizationBox(ColorQuantizationBox source)
{
SignifigantBits = source.SignifigantBits;
Histogram = source.Histogram;
HistogramTotal = source.HistogramTotal;
MinRed = source.MinRed;
MaxRed = source.MaxRed;
MinGreen = source.MinGreen;
MaxGreen = source.MaxGreen;
MinBlue = source.MinBlue;
MaxBlue = source.MaxBlue;
}
public Tuple <ColorQuantizationBox, ColorQuantizationBox> MedianCut()
{
if (this.HistogramTotal <= 1)
{
return(new Tuple <ColorQuantizationBox, ColorQuantizationBox>(this, null));
}
uint total = 0;
uint[] partialSum = null;
RGBAxis primaryAxis = WidestAxis;
byte primaryMin, primaryMax;
if (primaryAxis == RGBAxis.Red)
{
primaryMin = MinRed;
primaryMax = MaxRed;
partialSum = new uint[RedRange + 1];
for (byte i = MinRed; i <= MaxRed; i++)
{
uint sum = 0;
for (byte j = MinGreen; j <= MaxGreen; j++)
{
for (byte k = MinBlue; k <= MaxBlue; k++)
{
var index = GetColorIndex(i, j, k, SignifigantBits);
sum += Histogram[index];
}
}
total += sum;
partialSum[i - primaryMin] = total;
}
}
else if (primaryAxis == RGBAxis.Green)
{
primaryMin = MinGreen;
primaryMax = MaxGreen;
partialSum = new uint[GreenRange + 1];
for (byte i = MinGreen; i <= MaxGreen; i++)
{
uint sum = 0;
for (byte j = MinRed; j <= MaxRed; j++)
{
for (byte k = MinBlue; k <= MaxBlue; k++)
{
var index = GetColorIndex(j, i, k, SignifigantBits);
sum += Histogram[index];
}
}
total += sum;
partialSum[i - primaryMin] = total;
}
}
else
{
primaryMin = MinBlue;
primaryMax = MaxBlue;
partialSum = new uint[BlueRange + 1];
for (byte i = MinBlue; i <= MaxBlue; i++)
{
uint sum = 0;
for (byte j = MinRed; j <= MaxRed; j++)
{
for (byte k = MinGreen; k <= MaxGreen; k++)
{
var index = GetColorIndex(j, k, i, SignifigantBits);
sum += Histogram[index];
}
}
total += sum;
partialSum[i - primaryMin] = total;
}
}
if (primaryMin == primaryMax)
{
return(new Tuple <ColorQuantizationBox, ColorQuantizationBox>(this, null));
}
uint[] lookAheadSum = new uint[partialSum.Length];
for (int i = 0; i < partialSum.Length; i++)
{
lookAheadSum[i] = total - partialSum[i];
}
for (byte i = primaryMin; i <= primaryMax; i++)
{
var partial = partialSum[i - primaryMin];
if (partial > total / 2)
{
float left = i - primaryMin;
float right = primaryMax - i;
int cutValue = 0;
if (left <= right)
{
cutValue = Math.Min(primaryMax - 1, (int)Math.Floor((float)i + right / 2f));
}
else
{
cutValue = Math.Max(primaryMin, (int)Math.Floor((float)i - 1f - left / 2f));
}
while (partialSum[cutValue - primaryMin] <= 0)
{
cutValue++;
}
if (cutValue - primaryMin >= partialSum.Length)
{
cutValue = partialSum.Length - 1 + primaryMin;
}
uint lookAhead = lookAheadSum[cutValue - primaryMin];
while (lookAhead == 0 && cutValue > primaryMin && partialSum[cutValue - primaryMin - 1] != 0)
{
cutValue--;
lookAhead = lookAheadSum[cutValue - primaryMin];
}
ColorQuantizationBox leftBox = null, rightBox = null;
if (primaryAxis == RGBAxis.Red)
{
leftBox = new ColorQuantizationBox(Histogram, MinRed, (byte)(cutValue), MinGreen, MaxGreen, MinBlue, MaxBlue, SignifigantBits);
rightBox = new ColorQuantizationBox(Histogram, (byte)(cutValue + 1), MaxRed, MinGreen, MaxGreen, MinBlue, MaxBlue, SignifigantBits);
}
else if (primaryAxis == RGBAxis.Green)
{
leftBox = new ColorQuantizationBox(Histogram, MinRed, MaxRed, MinGreen, (byte)(cutValue), MinBlue, MaxBlue, SignifigantBits);
rightBox = new ColorQuantizationBox(Histogram, MinRed, MaxRed, (byte)(cutValue + 1), MaxGreen, MinBlue, MaxBlue, SignifigantBits);
}
else
{
leftBox = new ColorQuantizationBox(Histogram, MinRed, MaxRed, MinGreen, MaxGreen, MinBlue, (byte)(cutValue), SignifigantBits);
rightBox = new ColorQuantizationBox(Histogram, MinRed, MaxRed, MinGreen, MaxGreen, (byte)(cutValue + 1), MaxBlue, SignifigantBits);
}
return(new Tuple <ColorQuantizationBox, ColorQuantizationBox>(leftBox, rightBox));
}
}
throw new Exception("Unable to find median partial sum. This should never happen");
}