AForge.Imaging.Filters.Dilatation3x3.ProcessFilter C# (CSharp) Method

        protected override unsafe void ProcessFilter( UnmanagedImage sourceData, UnmanagedImage destinationData, Rectangle rect )
        {
            if ( ( rect.Width < 3 ) || ( rect.Height < 3 ) )
            {
                throw new InvalidImagePropertiesException( "Processing rectangle mast be at least 3x3 in size." );
            }

            // processing start and stop X,Y positions
            int startX  = rect.Left + 1;
            int startY  = rect.Top + 1;
            int stopX   = rect.Right - 1;
            int stopY   = rect.Bottom - 1;

            int dstStride = destinationData.Stride;
            int srcStride = sourceData.Stride;

            int dstOffset = dstStride - rect.Width + 1;
            int srcOffset = srcStride - rect.Width + 1;

            // image pointers
            byte* src = (byte*) sourceData.ImageData.ToPointer( );
            byte* dst = (byte*) destinationData.ImageData.ToPointer( );

            byte max;

            // allign pointers by X and Y
            src += ( startX - 1 ) + ( startY - 1 ) * srcStride;
            dst += ( startX - 1 ) + ( startY - 1 ) * dstStride;

            // --- process the first line
            max = *src;

            if ( src[1] > max )
                max = src[1];
            if ( src[srcStride] > max )
                max = src[srcStride];
            if ( src[srcStride + 1] > max )
                max = src[srcStride + 1];

            *dst = max;

            src++;
            dst++;

            // for each pixel
            for ( int x = startX; x < stopX; x++, src++, dst++ )
            {
                max = *src;

                if ( src[-1] > max )
                    max = src[-1];
                if ( src[1] > max )
                    max = src[1];
                if ( src[srcStride - 1] > max )
                    max = src[srcStride - 1];
                if ( src[srcStride] > max )
                    max = src[srcStride];
                if ( src[srcStride + 1] > max )
                    max = src[srcStride + 1];

                *dst = max;
            }

            max = *src;

            if ( src[-1] > max )
                max = src[-1];
            if ( src[srcStride - 1] > max )
                max = src[srcStride - 1];
            if ( src[srcStride] > max )
                max = src[srcStride];

            *dst = max;

            src += srcOffset;
            dst += dstOffset;

            // --- process all lines except the last one
            for ( int y = startY; y < stopY; y++ )
            {
                max = *src;

                if ( src[1] > max )
                    max = src[1];
                if ( src[-srcStride] > max )
                    max = src[-srcStride];
                if ( src[-srcStride + 1] > max )
                    max = src[-srcStride + 1];
                if ( src[srcStride] > max )
                    max = src[srcStride];
                if ( src[srcStride + 1] > max )
                    max = src[srcStride + 1];

                *dst = max;

                src++;
                dst++;

                // for each pixel
                for ( int x = startX; x < stopX; x++, src++, dst++ )
                {
                    max = *src;

                    if ( src[-1] > max )
                        max = src[-1];
                    if ( src[1] > max )
                        max = src[1];
                    if ( src[-srcStride - 1] > max )
                        max = src[-srcStride - 1];
                    if ( src[-srcStride] > max )
                        max = src[-srcStride];
                    if ( src[-srcStride + 1] > max )
                        max = src[-srcStride + 1];
                    if ( src[srcStride - 1] > max )
                        max = src[srcStride - 1];
                    if ( src[srcStride] > max )
                        max = src[srcStride];
                    if ( src[srcStride + 1] > max )
                        max = src[srcStride + 1];

                    *dst = max;
                }

                max = *src;

                if ( src[-1] > max )
                    max = src[-1];
                if ( src[-srcStride - 1] > max )
                    max = src[-srcStride - 1];
                if ( src[-srcStride] > max )
                    max = src[-srcStride];
                if ( src[srcStride - 1] > max )
                    max = src[srcStride - 1];
                if ( src[srcStride] > max )
                    max = src[srcStride];

                *dst = max;

                src += srcOffset;
                dst += dstOffset;
            }

            // --- process the last line
            *dst = (byte) ( *src | src[1] | src[-srcStride] | src[-srcStride + 1] );

            max = *src;

            if ( src[1] > max )
                max = src[1];
            if ( src[-srcStride] > max )
                max = src[-srcStride];
            if ( src[-srcStride + 1] > max )
                max = src[-srcStride + 1];

            *dst = max;

            src++;
            dst++;

            // for each pixel
            for ( int x = startX; x < stopX; x++, src++, dst++ )
            {
                max = *src;

                if ( src[-1] > max )
                    max = src[-1];
                if ( src[1] > max )
                    max = src[1];
                if ( src[-srcStride - 1] > max )
                    max = src[-srcStride - 1];
                if ( src[-srcStride] > max )
                    max = src[-srcStride];
                if ( src[-srcStride + 1] > max )
                    max = src[-srcStride + 1];

                *dst = max;
            }

            max = *src;

            if ( src[-1] > max )
                max = src[-1];
            if ( src[-srcStride - 1] > max )
                max = src[-srcStride - 1];
            if ( src[-srcStride] > max )
                max = src[-srcStride];

            *dst = max;
        }
    }