Nice work!
I could quickly make a bar chart, and using that, as a component, a small multiple (trellis) chart reusing that. Also experienced the fun of accidentally embedding one group in itself, stack exhausted :-)
A couple of questions:
1. Any way to add real datasources on the demo pages? Doesn't have to be big, and could be a json. I guess with a local install, or if the page embedding that was asked before gets implemented, it'll be possible to access at least global variables. Is there a preferred way to access data, e.g. using general JS functions? Since Apparatus feels FRP inspired, maybe LINQ, or something similar to crossfilter.js?
2. I'm interested in the choice of canvas, and pros/cons with SVG and WebGL - I'm not lacking thoughts about that, but find it interesting.
3. Method of extensibility? For example, now, A + B = C makes it possible to e.g. create a rectangle that encompasses two adjacent smaller rectanges. Is it or will it be possible to use whatever function I want, e.g. importing cassowary.js.
Robert