private static BlurColor GetColor(BlurColor[,] buffer, int x, int y)
{
x = Math.Max(0, Math.Min(buffer.GetLength(0) - 1, x));
y = Math.Max(0, Math.Min(buffer.GetLength(1) - 1, y));
return buffer[x, y];
}
public static Bitmap Generate(Image image, double sigma)
{
var scaleFactor = 1.5 * sigma + 1;
var kernelWidth = (int)Math.Round((3 * sigma) / scaleFactor);
if (kernelWidth == 0)
return new Bitmap(image);
var kernel = new double[kernelWidth];
for (var i = 0; i < kernelWidth; i++)
{
var x = i * scaleFactor;
kernel[i] = Math.Exp(-x * x / (2 * sigma * sigma)) / (sigma * Math.Sqrt(2 * Math.PI));
}
var overallWeight = kernel[0];
for (var i = 1; i < kernelWidth; i++)
{
overallWeight += 2 * kernel[i];
}
var width = (int)Math.Round(image.Width / scaleFactor);
var height = (int)Math.Round(image.Height / scaleFactor);
var sourceImage = new Bitmap(image, width, height);
var resultImage = sourceImage;
var sourceBuffer = new BlurColor[width, height];
var tempBuffer = new BlurColor[width, height];
for (var y = 0; y < height; y++)
{
for (var x = 0; x < width; x++)
{
sourceBuffer[x, y] = new BlurColor(sourceImage.GetPixel(x, y));
}
}
for (var y = 0; y < height; y++)
{
Parallel.For(0, width, x =>
{
var result = kernel[0] * GetColor(sourceBuffer, x, y);
for (var i = 1; i < kernelWidth; i++)
{
var weight = kernel[i];
result += weight * (GetColor(sourceBuffer, x - i, y) + GetColor(sourceBuffer, x + i, y));
}
result /= overallWeight;
tempBuffer[x, y] = result;
});
}
for (var y = 0; y < height; y++)
{
Parallel.For(0, width, x =>
{
var result = kernel[0] * GetColor(tempBuffer, x, y);
for (var i = 1; i < kernelWidth; i++)
{
var weight = kernel[i];
result += weight * (GetColor(tempBuffer, x, y - i) + GetColor(tempBuffer, x, y + i));
}
result /= overallWeight;
lock (resultImage)
{
resultImage.SetPixel(x, y, result.ActualColor);
}
});
}
return resultImage;
}
public static Bitmap Generate(Image image, double sigma)
{
var scaleFactor = 1.5 * sigma + 1;
var kernelWidth = (int)Round((3 * sigma) / scaleFactor);
if (kernelWidth == 0)
{
return(new Bitmap(image));
}
var kernel = new double[kernelWidth];
for (var i = 0; i < kernelWidth; i++)
{
var x = i * scaleFactor;
kernel[i] = Exp(-x * x / (2 * sigma * sigma)) / (sigma * Sqrt(2 * PI));
}
var overallWeight = kernel[0];
for (var i = 1; i < kernelWidth; i++)
{
overallWeight += 2 * kernel[i];
}
var width = (int)Round(image.Width / scaleFactor);
var height = (int)Round(image.Height / scaleFactor);
var sourceImage = new Bitmap(image, width, height);
var resultImage = sourceImage;
var sourceBuffer = new BlurColor[width, height];
var tempBuffer = new BlurColor[width, height];
for (var y = 0; y < height; y++)
{
for (var x = 0; x < width; x++)
{
sourceBuffer[x, y] = new BlurColor(sourceImage.GetPixel(x, y));
}
}
for (var y = 0; y < height; y++)
{
Parallel.For(0, width, x =>
{
var result = kernel[0] * GetColor(sourceBuffer, x, y);
for (var i = 1; i < kernelWidth; i++)
{
var weight = kernel[i];
result += weight * (GetColor(sourceBuffer, x - i, y) + GetColor(sourceBuffer, x + i, y));
}
result /= overallWeight;
tempBuffer[x, y] = result;
});
}
for (var y = 0; y < height; y++)
{
Parallel.For(0, width, x =>
{
var result = kernel[0] * GetColor(tempBuffer, x, y);
for (var i = 1; i < kernelWidth; i++)
{
var weight = kernel[i];
result += weight * (GetColor(tempBuffer, x, y - i) + GetColor(tempBuffer, x, y + i));
}
result /= overallWeight;
lock (resultImage)
{
resultImage.SetPixel(x, y, result.ActualColor);
}
});
}
return(resultImage);
}
