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

        protected override unsafe void ProcessFilter( UnmanagedImage image, Rectangle rect )
        {
            int pixelSize = Image.GetPixelFormatSize( image.PixelFormat ) / 8;

            // processing width and height
            int width  = rect.Width;
            int height = rect.Height;

            // processing region's dimension
            int widthToProcess  = width;
            int heightToProcess = height;

            // if generator was specified, then generate a texture
            // otherwise use provided texture
            if ( textureGenerator != null )
            {
                texture = textureGenerator.Generate( width, height );
            }
            else
            {
                widthToProcess  = Math.Min( width, texture.GetLength( 1 ) );
                heightToProcess = Math.Min( height, texture.GetLength( 0 ) );
            }

            int offset = image.Stride - widthToProcess * pixelSize;

            // do the job
            byte* ptr = (byte*) image.ImageData.ToPointer( );

            // allign pointer to the first pixel to process
            ptr += ( rect.Top * image.Stride + rect.Left * pixelSize );

            // texture
            for ( int y = 0; y < heightToProcess; y++ )
            {
                for ( int x = 0; x < widthToProcess; x++ )
                {
                    double t = texture[y, x];
                    // process each pixel
                    for ( int i = 0; i < pixelSize; i++, ptr++ )
                    {
                        *ptr = (byte) Math.Min( 255.0f, ( preserveLevel * ( *ptr ) ) + ( filterLevel * ( *ptr ) ) * t );
                    }
                }
                ptr += offset;
            }
        }
    }