function TooltipContent(container, api, opt) {
    if (env$1.wxa) {
        return null;
    }

    var el = document.createElement('div');
    el.domBelongToZr = true;
    this.el = el;
    var zr = this._zr = api.getZr();
    var appendToBody = this._appendToBody = opt && opt.appendToBody;

    this._styleCoord = [0, 0];

    makeStyleCoord(this._styleCoord, zr, appendToBody, api.getWidth() / 2, api.getHeight() / 2);

    if (appendToBody) {
        document.body.appendChild(el);
    }
    else {
        container.appendChild(el);
    }

    this._container = container;

    this._show = false;

    /**
     * @private
     */
    this._hideTimeout;

    // FIXME
    // Is it needed to trigger zr event manually if
    // the browser do not support `pointer-events: none`.

    var self = this;
    el.onmouseenter = function () {
        // clear the timeout in hideLater and keep showing tooltip
        if (self._enterable) {
            clearTimeout(self._hideTimeout);
            self._show = true;
        }
        self._inContent = true;
    };
    el.onmousemove = function (e) {
        e = e || window.event;
        if (!self._enterable) {
            // `pointer-events: none` is set to tooltip content div
            // if `enterable` is set as `false`, and `el.onmousemove`
            // can not be triggered. But in browser that do not
            // support `pointer-events`, we need to do this:
            // Try trigger zrender event to avoid mouse
            // in and out shape too frequently
            var handler = zr.handler;
            var zrViewportRoot = zr.painter.getViewportRoot();
            normalizeEvent(zrViewportRoot, e, true);
            handler.dispatch('mousemove', e);
        }
    };
    el.onmouseleave = function () {
        if (self._enterable) {
            if (self._show) {
                self.hideLater(self._hideDelay);
            }
        }
        self._inContent = false;
    };
}
Set tooltip content

@param {string} content rich text string of content
@param {Object} markerRich rich text style
@param {Object} tooltipModel tooltip model