*      not drawn on the mapboard.
     */
    public Point getTilePosition(Tile t) {
        repositionMapIfNeeded();
        if (isTileVisible(t)) {
            int x = ((t.getX() - leftColumn) * tileWidth) + leftColumnX;
            int y = ((t.getY() - topRow) * halfHeight) + topRowY;
            if ((t.getY() % 2) != 0) {
                x += halfWidth;
            }
            return new Point(x, y);
        } else {
            return null;
        }
    }