The Tablet Tester is a simple online tool to better understand how digital pens work. It is useful for troublehooting pen problems and ans as a basis for developers to explore pen behavior. It is NOT intended as a creative digital painting app, even though it has some similarities.
https://docs.thesevenpens.com/drawtab/developers/online-tablet-tester
https://github.com/TheSevenPens/HtmlTabletTester
https://developer.mozilla.org/en-US/docs/Web/API/Pointer_events