private static void Convolute(BMPImage image, double[] kernel)
{
byte[][][] copy = new byte[image.Height][][];
for (int i = 0; i < image.Height; i++)
{
copy[i] = new byte[image.Width][];
for (int j = 0; j < image.Width; j++)
{
copy[i][j] = new byte[image.Channels];
}
}
for (int i = 1; i < image.Height - 1; i++)
{
for (int j = 1; j < image.Width - 1; j++)
{
for (int c = 0; c < image.Channels; c++)
{
double pixelByte = 0;
for (int k = -1; k < 2; k++)
{
for (int l = -1; l < 2; l++)
{
pixelByte += kernel[(k + 1) * 3 + l + 1] * image.Bytes[i + k][j + l][c];
}
}
if (pixelByte == 0)
{
copy[i][j][c] = 0;
}
else if (Math.Abs(pixelByte) < 255)
{
copy[i][j][c] = (byte)Math.Abs(pixelByte);
}
else
{
copy[i][j][c] = 255;
}
}
}
}
for (int i = 0; i < image.Height; i++)
{
for (int j = 0; j < image.Width; j++)
{
for (int c = 0; c < image.Channels; c++)
{
image.Bytes[i][j][c] = copy[i][j][c];
}
}
}
}
public static void ApplyGrayscale(BMPImage image)
{
for (int i = 1; i < image.Height - 1; i++)
{
for (int j = 1; j < image.Width - 1; j++)
{
for (int c = 0; c < image.Channels; c++)
{
if (c == 3)
{
image.Bytes[i][j][c] = 255;
}
else
{
image.Bytes[i][j][c] = (byte)Math.Max(image.Bytes[i][j][2], Math.Max(image.Bytes[i][j][1], image.Bytes[i][j][0]));
}
}
}
}
}
public static void ApplyMedian(BMPImage image)
{
for (int i = 1; i < image.Height - 1; i++)
{
for (int j = 1; j < image.Width - 1; j++)
{
for (int c = 0; c < image.Channels; c++)
{
int[] surroundings = new int[9];
for (int k = -1; k < 2; k++)
{
for (int l = -1; l < 2; l++)
{
surroundings[(k + 1) * 3 + l + 1] = image.Bytes[i + k][j + l][c];
}
}
Array.Sort(surroundings);
image.Bytes[i][j][c] = (byte)surroundings[4];
}
}
}
}
static void Main(string[] args)
{
Console.WriteLine("This program applies to input 24 or 32 bit BMP image one of median, gauss, sobelX, sobelY, grayscale filters.");
if (args.Length != 3)
{
Console.WriteLine("Input error. Please, enter data in following order: program name, input file, filter name, output file.");
return;
}
if (String.Compare(args[1], "median") != 0 && String.Compare(args[1], "gauss") != 0 && String.Compare(args[1], "sobelX") != 0 && String.Compare(args[1], "sobelY") != 0 && String.Compare(args[1], "grayscale") != 0)
{
Console.WriteLine("There is only median, gauss, sobelX, sobelY and grayscale filters.");
return;
}
FileStream input;
try
{
input = new FileStream(args[0], FileMode.Open, FileAccess.Read);
}
catch (FileNotFoundException)
{
Console.WriteLine("File not found.");
return;
}
BMPImage image = new BMPImage(input);
FileStream output;
try
{
output = new FileStream(args[2], FileMode.OpenOrCreate, FileAccess.Write);
}
catch (Exception)
{
Console.WriteLine("Failed to create or to find output file.");
input.Close();
return;
}
if (args[1].Equals("median"))
{
Filters.ApplyMedian(image);
}
else if (args[1].Equals("gauss"))
{
Filters.ApplyGauss(image);
}
else if (args[1].Equals("sobelX"))
{
Filters.ApplySobelX(image);
}
else if (args[1].Equals("sobelY"))
{
Filters.ApplySobelY(image);
}
else if (args[1].Equals("grayscale"))
{
Filters.ApplyGrayscale(image);
}
image.WriteToFile(output);
input.Close();
output.Close();
}
public static void ApplySobelY(BMPImage image)
{
double[] kernel = new double[] { 1, 2, 1, 0, 0, 0, -1, -2, -1 };
Convolute(image, kernel);
}
public static void ApplyGauss(BMPImage image)
{
double[] kernel = new double[] { 0.0626, 0.1250, 0.0626, 0.1250, 0.2497, 0.1250, 0.0626, 0.1250, 0.0626 };
Convolute(image, kernel);
}
