Inverting the colors of an SWT Image

I've come up with a way to invert the colors of an swt image using AWT. My knowledge of color palletes is limited so I found this backwards way to do it... Below is the code. Basically I convert SWT image data into a buffered image with an indexed RGB color pallete then do the color inversion and convert it back to SWT image...

 
public static ImageData invertImageColors(ImageData imageData) {  
    if (!imageData.palette.isDirect) {  
        int width = imageData.width;  
        int height = imageData.height;  
        for (int i = 0; i < width; i++) {  
            for (int j = 0; j < height; j++) {  
                imageData.setPixel(i, j, 255 - imageData.getPixel(i, j));  
            }  
        }  
        return imageData;  
    } else {  
        /*  
         * My basic algorithm here is to convert to AWT buffered image, re-pack that
         * into a BufferedImage.TYPE_INT_RGB buffered image, and then convert that          
         * back to an SWT image  
         */  
         BufferedImage awtImage = convertToAWT(imageData);  
         BufferedImage destImage = new BufferedImage(awtImage.getWidth(),
               awtImage.getHeight(), BufferedImage.TYPE_INT_RGB);  
         Graphics2D awtGraphicsContext = destImage.createGraphics();  
         awtGraphicsContext.drawImage(awtImage, null, 0, 0);  
         awtGraphicsContext.dispose();  
         short[] invert = new short[256];  
         for (int i = 0; i < invert.length; i++)  
             invert[i] = (short) (255 - i);  
         BufferedImageOp invertOp = new LookupOp(new ShortLookupTable(0, invert), null);  
         destImage = invertOp.filter(destImage, null);  
         return convertToSWT(destImage);  
    }  
 }  

And the code to convert between an SWT image and AWT BufferedImage. Note, I found this code on the interwebs

    public static ImageData convertToSWT(BufferedImage bufferedImage) {
        if (bufferedImage.getColorModel() instanceof DirectColorModel) {
            DirectColorModel colorModel = (DirectColorModel) bufferedImage.getColorModel();
            PaletteData palette = new PaletteData(colorModel.getRedMask(), colorModel.getGreenMask(),
                    colorModel.getBlueMask());
            ImageData data = new ImageData(bufferedImage.getWidth(), bufferedImage.getHeight(), colorModel.getPixelSize(),
                    palette);
            WritableRaster raster = bufferedImage.getRaster();
            int[] pixelArray = new int[3];
            for (int y = 0; y < data.height; y++) {
                for (int x = 0; x < data.width; x++) {
                    raster.getPixel(x, y, pixelArray);
                    int pixel = palette.getPixel(new RGB(pixelArray[0], pixelArray[1], pixelArray[2]));
                    data.setPixel(x, y, pixel);
                }
            }
            return data;
        } else if (bufferedImage.getColorModel() instanceof IndexColorModel) {
            IndexColorModel colorModel = (IndexColorModel) bufferedImage.getColorModel();
            int size = colorModel.getMapSize();
            byte[] reds = new byte[size];
            byte[] greens = new byte[size];
            byte[] blues = new byte[size];
            colorModel.getReds(reds);
            colorModel.getGreens(greens);
            colorModel.getBlues(blues);
            RGB[] rgbs = new RGB[size];
            for (int i = 0; i < rgbs.length; i++) {
                rgbs[i] = new RGB(reds[i] & 0xFF, greens[i] & 0xFF, blues[i] & 0xFF);
            }
            PaletteData palette = new PaletteData(rgbs);
            ImageData data = new ImageData(bufferedImage.getWidth(), bufferedImage.getHeight(), colorModel.getPixelSize(),
                    palette);
            data.transparentPixel = colorModel.getTransparentPixel();
            WritableRaster raster = bufferedImage.getRaster();
            int[] pixelArray = new int[1];
            for (int y = 0; y < data.height; y++) {
                for (int x = 0; x < data.width; x++) {
                    raster.getPixel(x, y, pixelArray);
                    data.setPixel(x, y, pixelArray[0]);
                }
            }
            return data;
        }
        return null;
    }