return tsize.width - ((tsize.width - horSide) / 2);
return tsize.width - ((tsize.width - (int)(horSide * zoom)) / 2);
    public int getScrollableUnitIncrement(Rectangle visibleRect,            int orientation, int direction) {        Dimension tsize = getTileSize(zoom);        if (orientation == SwingConstants.VERTICAL) {            return tsize.height - ((tsize.height - verSide) / 2);        } else {            return tsize.width - ((tsize.width - horSide) / 2);        }    }