Is element in client view. use tangram

inView.js

var inView = function (e) {
    var clientW = baidu.page.getViewWith();
    var clientH = baidu.page.getViewHeight();
    var rect = e.getBoundingClientRect();
    return (rect.bottom > 0 && rect.top < clientH)
        && (rect.right > 0 && rect.left < clientW);
};