public WriteableBitmap ProcessImage(BitmapImage originalBitmapImage)
{
WriteableBitmap writableImage = new WriteableBitmap(originalBitmapImage);
byte[] byteArr = writableImage.WriteableBitMapImageToArray();
for (int i = 0; i < byteArr.Length; i += 4)
{
byte a = byteArr[i + 3];
if (a > 0)
{
double ad = (double)a / 255.0;
double rd = (double)byteArr[i + 2] / ad;
double gd = (double)byteArr[i + 1] / ad;
double bd = (double)byteArr[i + 0] / ad;
double luminance = 0.2126 * rd + 0.7152 * gd + 0.0722 * bd;
double newR = luminance * ad;
int interval = 256 / this.Levels;
int low = 0, high = interval;
for (int j = 0; j < this.Levels; j++)
{
if (newR > low && newR < high)
{
if (newR - low > high - newR)
{
newR = high;
}
else
{
newR = low;
}
}
low += interval;
high += interval;
}
if (newR > 255)
{
newR = 255;
}
byteArr[i + 0] = (byte)newR;
byteArr[i + 1] = (byte)newR;
byteArr[i + 2] = (byte)newR;
}
}
WriteableBitmap result = originalBitmapImage.ByteArrayToWritableBitmap(byteArr);
return(result);
}