Updated code (now much faster, requires use of UNSAFE keyword)
static void Main(string[] args)
{
Bitmap bitmap = new Bitmap("C:\\Users\\erik\\test.png");
bitmap = Blur(bitmap, 10);
bitmap.Save("C:\\Users\\erik\\test2.png");
}
private static Bitmap Blur(Bitmap image, Int32 blurSize)
{
return Blur(image, new Rectangle(0, 0, image.Width, image.Height), blurSize);
}
private unsafe static Bitmap Blur(Bitmap image, Rectangle rectangle, Int32 blurSize)
{
Bitmap blurred = new Bitmap(image.Width, image.Height);
// make an exact copy of the bitmap provided
using (Graphics graphics = Graphics.FromImage(blurred))
graphics.DrawImage(image, new Rectangle(0, 0, image.Width, image.Height),
new Rectangle(0, 0, image.Width, image.Height), GraphicsUnit.Pixel);
// Lock the bitmap's bits
BitmapData blurredData = blurred.LockBits(new Rectangle(0, 0, image.Width, image.Height), ImageLockMode.ReadWrite, blurred.PixelFormat);
// Get bits per pixel for current PixelFormat
int bitsPerPixel = Image.GetPixelFormatSize(blurred.PixelFormat);
// Get pointer to first line
byte* scan0 = (byte*)blurredData.Scan0.ToPointer();
// look at every pixel in the blur rectangle
for (int xx = rectangle.X; xx < rectangle.X + rectangle.Width; xx++)
{
for (int yy = rectangle.Y; yy < rectangle.Y + rectangle.Height; yy++)
{
int avgR = 0, avgG = 0, avgB = 0;
int blurPixelCount = 0;
// average the color of the red, green and blue for each pixel in the
// blur size while making sure you don't go outside the image bounds
for (int x = xx; (x < xx + blurSize && x < image.Width); x++)
{
for (int y = yy; (y < yy + blurSize && y < image.Height); y++)
{
// Get pointer to RGB
byte* data = scan0 + y * blurredData.Stride + x * bitsPerPixel / 8;
avgB += data[0]; // Blue
avgG += data[1]; // Green
avgR += data[2]; // Red
blurPixelCount++;
}
}
avgR = avgR / blurPixelCount;
avgG = avgG / blurPixelCount;
avgB = avgB / blurPixelCount;
// now that we know the average for the blur size, set each pixel to that color
for (int x = xx; x < xx + blurSize && x < image.Width && x < rectangle.Width; x++)
{
for (int y = yy; y < yy + blurSize && y < image.Height && y < rectangle.Height; y++)
{
// Get pointer to RGB
byte* data = scan0 + y * blurredData.Stride + x * bitsPerPixel / 8;
// Change values
data[0] = (byte)avgB;
data[1] = (byte)avgG;
data[2] = (byte)avgR;
}
}
}
}
// Unlock the bits
blurred.UnlockBits(blurredData);
return blurred;
}
Took 2.356 seconds to process 256x256 image with blur value 10.
Original Code (from Github - slightly altered)
static void Main(string[] args)
{
Bitmap bitmap = new Bitmap("C:\\Users\\erik\\test.png");
bitmap = Blur(bitmap, 10);
bitmap.Save("C:\\Users\\erik\\test2.png");
}
private static Bitmap Blur(Bitmap image, Int32 blurSize)
{
return Blur(image, new Rectangle(0, 0, image.Width, image.Height), blurSize);
}
private static Bitmap Blur(Bitmap image, Rectangle rectangle, Int32 blurSize)
{
Bitmap blurred = new Bitmap(image.Width, image.Height);
// make an exact copy of the bitmap provided
using (Graphics graphics = Graphics.FromImage(blurred))
graphics.DrawImage(image, new Rectangle(0, 0, image.Width, image.Height),
new Rectangle(0, 0, image.Width, image.Height), GraphicsUnit.Pixel);
// look at every pixel in the blur rectangle
for (int xx = rectangle.X; xx < rectangle.X + rectangle.Width; xx++)
{
for (int yy = rectangle.Y; yy < rectangle.Y + rectangle.Height; yy++)
{
int avgR = 0, avgG = 0, avgB = 0;
int blurPixelCount = 0;
// average the color of the red, green and blue for each pixel in the
// blur size while making sure you don't go outside the image bounds
for (int x = xx; (x < xx + blurSize && x < image.Width); x++)
{
for (int y = yy; (y < yy + blurSize && y < image.Height); y++)
{
Color pixel = blurred.GetPixel(x, y);
avgR += pixel.R;
avgG += pixel.G;
avgB += pixel.B;
blurPixelCount++;
}
}
avgR = avgR / blurPixelCount;
avgG = avgG / blurPixelCount;
avgB = avgB / blurPixelCount;
// now that we know the average for the blur size, set each pixel to that color
for (int x = xx; x < xx + blurSize && x < image.Width && x < rectangle.Width; x++)
for (int y = yy; y < yy + blurSize && y < image.Height && y < rectangle.Height; y++)
blurred.SetPixel(x, y, Color.FromArgb(avgR, avgG, avgB));
}
}
return blurred;
}
Took 7.594 seconds to process 256x256 image with blur value 10.
Orignal Image
Blurred Image (blur level 10)
Image from: https://www.pexels.com/search/landscape/
