tipbox内容太多显示不全问题

position: function (point, params, dom, rect, size) {
    var x = point[0];//
    var y = point[1];
    var viewWidth = size.viewSize[0];
    var viewHeight = size.viewSize[1];
    var boxWidth = size.contentSize[0];
    var boxHeight = size.contentSize[1];
    var posX = 0;//x坐标位置
    var posY = 0;//y坐标位置

    if (x < boxWidth) {//左边放不开
        posX = 5;
    } else {//左边放的下
        posX = x - boxWidth;
    }

    if (y < boxHeight) {//上边放不开
        posY = 5;
    } else {//上边放得下
        posY = y - boxHeight;
    }
    return [posX, posY];
}