abstract static class Surface extends JPanel {
  public BufferedImage bimg;
  public int imageType;
  public boolean clearSurface = true;

  private Toolkit toolkit;
  private int biw, bih;
  private boolean clearOnce;

  public Surface() {
    setDoubleBuffered(false);
    toolkit = getToolkit();
    setImageType(0);
  }

  public int getImageType() {
    return imageType;
  }

  public void setImageType(int imgType) {
    if (imgType == 0) {
      imageType = 1;
    } else {
      imageType = imgType;
    }
    bimg = null;
  }

  public BufferedImage createBufferedImage(Graphics2D g2, int w, int h, int imgType) {
    BufferedImage bi = null;
    if (imgType == 0) {
      bi = (BufferedImage) g2.getDeviceConfiguration().
        createCompatibleImage(w, h);
    } else if (imgType > 0 && imgType < 14) {
      bi = new BufferedImage(w, h, imgType);
    } else if (imgType == 14) {
      bi = createBinaryImage(w, h, 2);
    } else if (imgType == 15) {
      bi = createBinaryImage(w, h, 4);
    } else if (imgType == 16) {
      bi = createSGISurface(w, h, 32);
    } else if (imgType == 17) {
      bi = createSGISurface(w, h, 16);
    }
    biw = w;
    bih = h;
    return bi;
  }


  // Lookup tables for BYTE_BINARY 1, 2 and 4 bits.
  static byte[] lut1Arr = new byte[] {0, (byte)255 };
  static byte[] lut2Arr = new byte[] {0, (byte)85, (byte)170, (byte)255};
  static byte[] lut4Arr = new byte[] {0, (byte)17, (byte)34, (byte)51,
    (byte)68, (byte)85,(byte) 102, (byte)119,
    (byte)136, (byte)153, (byte)170, (byte)187,
    (byte)204, (byte)221, (byte)238, (byte)255};


  private BufferedImage createBinaryImage(int w, int h, int pixelBits) {
    int bytesPerRow = w * pixelBits / 8;
    if (w * pixelBits % 8 != 0) {
      bytesPerRow++;
    }
    byte[] imageData = new byte[h * bytesPerRow];
    IndexColorModel cm = null;
    switch (pixelBits) {
      case 1:
        cm = new IndexColorModel(pixelBits, lut1Arr.length,
          lut1Arr, lut1Arr, lut1Arr);
        break;
      case 2:
        cm = new IndexColorModel(pixelBits, lut2Arr.length,
          lut2Arr, lut2Arr, lut2Arr);
        break;
      case 4:
        cm = new IndexColorModel(pixelBits, lut4Arr.length,
          lut4Arr, lut4Arr, lut4Arr);
        break;
      default:
      {new Exception("Invalid # of bit per pixel").printStackTrace();}
    }

    DataBuffer db = new DataBufferByte(imageData, imageData.length);
    WritableRaster r = Raster.createPackedRaster(db, w, h, pixelBits, null);
    return new BufferedImage(cm, r, false, null);
  }

  private BufferedImage createSGISurface(int w, int h, int pixelBits) {
    int rMask32 = 0xFF000000;
    int rMask16 = 0xF800;
    int gMask32 = 0x00FF0000;
    int gMask16 = 0x07C0;
    int bMask32 = 0x0000FF00;
    int bMask16 = 0x003E;

    DirectColorModel dcm = null;
    DataBuffer db = null;
    WritableRaster wr = null;
    switch (pixelBits) {
      case 16:
        short[] imageDataUShort = new short[w * h];
        dcm = new DirectColorModel(16, rMask16, gMask16, bMask16);
        db = new DataBufferUShort(imageDataUShort, imageDataUShort.length);
        wr = Raster.createPackedRaster(db, w, h, w,
          new int[] {rMask16, gMask16, bMask16},
          null);
        break;
      case 32:
        int[] imageDataInt = new int[w * h];
        dcm = new DirectColorModel(32, rMask32, gMask32, bMask32);
        db = new DataBufferInt(imageDataInt, imageDataInt.length);
        wr = Raster.createPackedRaster(db, w, h, w,
          new int[] {rMask32, gMask32, bMask32},
          null);
        break;
      default:
      {new Exception("Invalid # of bit per pixel").printStackTrace();}
    }

    return new BufferedImage(dcm, wr, false, null);
  }

  public Graphics2D createGraphics2D(int width, int height, BufferedImage bi, Graphics g) {

    Graphics2D g2 = null;

    if (bi != null) {
      g2 = bi.createGraphics();
    } else {
      g2 = (Graphics2D) g;
    }

    g2.setBackground(getBackground());

    if (clearSurface || clearOnce) {
      g2.clearRect(0, 0, width, height);
      clearOnce = false;
    }

    return g2;
  }

  public abstract void render(int w, int h, Graphics2D g);

  public void paintImmediately(int x,int y,int w, int h) {
    RepaintManager repaintManager = null;
    boolean save = true;
    if (!isDoubleBuffered()) {
      repaintManager = RepaintManager.currentManager(this);
      save = repaintManager.isDoubleBufferingEnabled();
      repaintManager.setDoubleBufferingEnabled(false);
    }
    super.paintImmediately(x, y, w, h);

    if (repaintManager != null)
      repaintManager.setDoubleBufferingEnabled(save);
  }

  public void paint(Graphics g) {
    Dimension d = getSize();

    if (imageType == 1)
      bimg = null;
    else if (bimg == null || biw != d.width || bih != d.height) {
      bimg = createBufferedImage((Graphics2D)g,
        d.width, d.height, imageType-2);
      clearOnce = true;
    }

    Graphics2D g2 = createGraphics2D(d.width, d.height, bimg, g);
    render(d.width, d.height, g2);
    g2.dispose();

    if (bimg != null) {
      g.drawImage(bimg, 0, 0, null);
      toolkit.sync();
    }
  }
}