public unsafe static void ModifyHistogram(WriteableBitmap image, int gMin, int gMax)
{
int[] redLookUpTable = new int[256];
int[] greenLookUpTable = new int[256];
int[] blueLookUpTable = new int[256];
double valueBase = gMax / gMin;
int sum = image.PixelHeight * image.PixelWidth;
HistogramData histogramData = GenerateHistogramData(image);
for (int i = 0; i < 256; i++)
{
double bluePower = GetPowerForHistogramModification(histogramData.BlueData, i, sum);
blueLookUpTable[i] = (int)(Math.Pow(valueBase, bluePower) * gMin);
double redPower = GetPowerForHistogramModification(histogramData.RedData, i, sum);
redLookUpTable[i] = (int)(Math.Pow(valueBase, redPower) * gMin);
double greenPower = GetPowerForHistogramModification(histogramData.GreenData, i, sum);
greenLookUpTable[i] = (int)(Math.Pow(valueBase, greenPower) * gMin);
}
ChangePixelsValue(image, redLookUpTable, new List <int>()
{
ColorChannel.Red
});
ChangePixelsValue(image, blueLookUpTable, new List <int>()
{
ColorChannel.Blue
});
ChangePixelsValue(image, greenLookUpTable, new List <int>()
{
ColorChannel.Green
});
}
public unsafe static HistogramData GenerateHistogramData(WriteableBitmap image)
{
HistogramData result = new HistogramData();
byte *imagePointer = (byte *)image.BackBuffer;
int stride = image.BackBufferStride;
for (int i = 0; i < image.PixelHeight; i++)
{
for (int j = 0; j < image.PixelWidth; j++)
{
int index = i * stride + j * ImageConstants.bytesPerPixel;
result.BlueData[imagePointer[index]]++;
index++;
result.GreenData[imagePointer[index]]++;
index++;
result.RedData[imagePointer[index]]++;
}
}
return(result);
}
