/**
     *  Swaps two colors in the bullseye
     *
     * @param id1, id2  Indices of colors to swap
     */
    public void swapColors(int id1, int id2) {
    	Color ctmp;
	    int nc = color.length;
	    if ((id1 >= 0)&&(id2 >= 0)&&(id1 < nc)&&(id2 < nc)) {
	        ctmp = color[id1];
	        color[id1] = color[id2];
	        color[id2] = ctmp;
	    }
	    repaint();
    }