Can somebody explain how you use canvas with ionic?

I am trying to use the Sketch.js library to paint strokes every time I touch the screen but I can’t get things to work.

The canvas ends up on top of everything and I can’t see the elements underneath it? Has anybody solved this problem?

And apart from Sketch.js, does anyone know how to make animations follow the fingers touch on the screen in some other way? :smiley: