https://nigeriagenealogy.ng/js/tngzoom.js

1const elem = document.getElementById('vcontainer');
2const zoomIn = document.getElementById('zoom-in');
3const zoomOut = document.getElementById('zoom-out');
4const zoomReset = document.getElementById('zoom-reset');
5var magIcons = $('#mag-icons-div');
6var outer = $('#outer');
7if(typeof zoomstep == 'undefined')
8	zoomstep = 0.2;
9const panzoom = Panzoom(elem, {step: zoomstep});
10const parent = elem.parentElement;
11//parent.addEventListener('wheel', panzoom.zoomWithWheel);
12zoomIn.addEventListener('click', panzoom.zoomIn)
13zoomOut.addEventListener('click', panzoom.zoomOut)
14zoomReset.addEventListener('click', panzoom.reset)
15
16$(window).scroll(function () {
17	var diff = outer.offset().top - $(window).scrollTop();
18	//console.log('outer: ' + outer.offset().top + ' win: ' + $(window).scrollTop() + ' diff: ' + diff);
19	var hasClass = magIcons.hasClass('mag-fixed');
20	if(diff < 102 && !hasClass) {
21		magIcons.addClass("mag-fixed");
22	} 
23	else if(diff > 40 && hasClass) {
24		magIcons.removeClass("mag-fixed");
25	}
26});