The PDF Viewer library allows you to customize the tooltip display for the annotations using the annotationMouseover and annotationMouseLeave events.
Step 1: Follow the steps provided in the link to create simple PDF Viewer sample.
Step 2: Add the following code snippet to display custom tooltip for the annotations.
viewer.annotationSettings.author = "syncfusion";
var tooltip = new ej.popups.Tooltip({
mouseTrail: true,
opensOn: "Custom"
});
viewer.annotationMouseover = function (args) {
tooltip.appendTo("#pdfViewer_pageDiv_" + (viewer.currentPageNumber - 1));
tooltip.content = args.annotation.author;
tooltip.open();
var ele = document.getElementsByClassName("e-tooltip-wrap")[0];
ele.style.top = args.Y + 100 + "px";
ele.style.left = args.X + "px";
};
viewer.annotationMouseLeave = function (args) {
tooltip.close();
};
Find the Sample how to display custom tooltip for annotations using Mouse over event