gistfile1.c

BOOL filter_2DConvolution(IMAGE* iImage, IMAGE* oImage, int F[3][3]) {
	int i, row, col; // counters
	int m = 3;
	int normalization = 0;
	int pixel, pos;
	int lastPixel = iImage->Width * iImage->Height - 1;

	printf("Filter:\n %d %d %d\n %d %d %d\n %d %d %d\n",
		F[0][0], F[0][1], F[0][2],
		F[1][0], F[1][1], F[1][2],
		F[2][0], F[2][1], F[2][2]);

	for (row = 0; row < m; row++) 
	{
		for (col = 0; col < m; col++)
		{
			normalization += F[row][col];
		}
	}
	printf("Normalization: %d\n", normalization);

	for (i = 0; i < LENGTH(iImage->Pixels); i++) 
	{
		pixel = pos = 0;

		for (row = -(m - 1)/2.0; row <= (m - 1)/2.0; row++)
		{
			for (col = -(m - 1)/2.0; col <= (m - 1)/2.0; col++)
			{
				pos = i + row * iImage->Width + col;
				if (pos >= 0 && pos <= lastPixel) // Check for top and bottom
				{
					if (i % iImage->Width == 0 && (pos + 1) % iImage->Width != 0) // check left
					{
						pixel += F[row][col] * iImage->Pixels[pos];
					}
					else if ( (i + 1) % iImage->Width == 0 && pos % iImage->Width != 0) // check right
					{
						pixel += F[row][col] * iImage->Pixels[pos];
					}
				}
			}
		}

		oImage->Pixels[i] = pixel / normalization;
	}
	return TRUE;
}