Accord.Imaging.Filters.BaseFilter2.ProcessFilter C# (CSharp) Method

        protected override unsafe void ProcessFilter(UnmanagedImage sourceData, UnmanagedImage destinationData)
        {
            PixelFormat pixelFormat = sourceData.PixelFormat;
            // get image dimension
            int width = sourceData.Width;
            int height = sourceData.Height;

            // check overlay type
            if (overlayImage != null)
            {
                // source image and overlay must have same pixel format
                if (pixelFormat != overlayImage.PixelFormat)
                    throw new InvalidImagePropertiesException("Source and overlay images must have same pixel format.");

                // check overlay image size
                if ((width != overlayImage.Width) || (height != overlayImage.Height))
                    throw new InvalidImagePropertiesException("Overlay image size must be equal to source image size.");

                // lock overlay image
                BitmapData ovrData = overlayImage.LockBits(
                    new Rectangle(0, 0, width, height),
                    ImageLockMode.ReadOnly, pixelFormat);

                try
                {
                    ProcessFilter(sourceData, new UnmanagedImage(ovrData), destinationData);
                }
                finally
                {
                    // unlock overlay image
                    overlayImage.UnlockBits(ovrData);
                }
            }
            else if (unmanagedOverlayImage != null)
            {
                // source image and overlay must have same pixel format
                if (pixelFormat != unmanagedOverlayImage.PixelFormat)
                    throw new InvalidImagePropertiesException("Source and overlay images must have same pixel format.");

                // check overlay image size
                if ((width != unmanagedOverlayImage.Width) || (height != unmanagedOverlayImage.Height))
                    throw new InvalidImagePropertiesException("Overlay image size must be equal to source image size.");

                ProcessFilter(sourceData, unmanagedOverlayImage, destinationData);
            }
            else
            {
                throw new InvalidOperationException("Overlay image is not set.");
            }
        }