I happen to be using a tablet now (Windows 2-in-1 device); going through all the examples on their Github page, all of them work perfectly with a pen (stylus)! That's impressive; something most interactive web stuff I've seen can't get right (collaborative whiteboards particularly suck at handling actual pens).
THANK YOU This seems framework agnostic – we might be able to embed this in our ember app.
I've been googling for this kind of library in the past couple of weeks and keep looking for "workflow editor" etc but simply haven't come up with any of these libraries.