public DoubleBufferWithBufferedImage() {
        setSize(300, 300);
        Dimension d = getSize();
        // w = (int)d.getWidth();
        // h = (int)d.getHeight();
        w = d.width;
        h = d.height;
        buffer = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
    }