There're definitely keywords I'm going to Google :) As for hierarchy, I'd like to avoid having class hierarchies where everything is a subclass of Widget, etc.

There're definitely keywords I'm going to Google :) As for hierarchy, I'd like to avoid having class hierarchies where everything is a subclass of Widget, etc. I guess I want to explore how much of the data required for rendering of such UI can lie in contiguous memory — hope it makes sense…