proce55ing is great for what it is / does, but there's a large gap between that and building functional games and animations, which isn't addressed by their screen graph model (nor this one). At issue, and missing, are parent-child relationships in which transformations and mouse events can be factored or transmitted up or down a display chain in the screen graph. To my knowledge, the only existing library that does this on Canvas is StrikeDisplay (strikedisplay.blogspot.com). In general, the ability to do that doesn't impinge on the ability to use native canvas vector functions in any way; but it simplifies the mixture of vector and raster images for animation, and acts as a better tool to let coders focus on the game they're trying to build rather than the intricacies of the canvas processing -- or to step it up, the raster and/or vector transformations -- behind something like:

var a = new Sprite(); var b = new Sprite(); a.addChild(b); b.x = 100; a.rotation = 45;

Which ideally should rotate both a and b by 45 degrees clockwise, with b offset in the rotation around a's axis by 100 px.