I suspect it was developed on a trackpad, which has pixel-level scroll precision. Zooming is a bit fast but generally fine on my MacBook Pro. Probably anything

I suspect it was developed on a trackpad, which has pixel-level scroll precision. Zooming is a bit fast but generally fine on my MacBook Pro. Probably anything like this should have a zoom slider (like Google Maps does) for people without precise scrolling or pinch zoom.