Cappuccino, Spoutcore or Homegrown solution for web based drawing application?

I'm currently looking at building an application for drawing entity relationships (data models).

Looking at both Sproutcore and Cappuccino they both look beefy enough to handle that kind of thing (see 280 slides for cappuccino example)...

Ideally I need a framework which lets users drag and drop components and then link them together and then when the user is done to be able to "freeze dry" these objects as JSON ready to be stored in some kind of database so they can be loaded again...

Which of the mentioned frameworks are more geared towards that already?

Or is the easiest to extend in the places where its lacking?

Or would it be easier开发者_如何学C in the long run to make my own using jQuery/prototype?

280Slides is a great real world example of what you can do as far as drawing goes, those shapes are obviously predefined, but you can draw whatever you want using our first class Graphics library (CoreGraphics). This means you also get most of the features you get in Canvas, but they also work in IE.

Atlas also does the linking together of components.

GoMockingbird is also a good example of an applications where you can easily lay out components.

The simple floor plan demo (with a tutorial) http://cappuccino.org/learn/demos/FloorPlan/index-deploy.html also gives you a good sense of the cool things you can do with first class drawing support.

Check out this Sproutcore demo: http://demo.sproutcore.com/family_tree/ -- that seems pretty close to what you are describing.

note that this demo uses some external frameworks; its not just Sproutcore.