[IPython-dev] widget models caching the view

Jason Grout jason-sage at creativetrax.com
Sat Feb 22 22:19:06 EST 2014

On 2/22/14 8:58 PM, Brian Granger wrote:
> Hi, sorry, just catching up. I am confused. I don't see how this is
> even possible. In browsers/DOM it is not possible to have a single DOM
> element displayed in multiple places on the page. Isn't that what this
> change tries to do? If it does work, I am guessing that it is broken -
> surely the events won't fire properly when the view is on the page
> multiple times.

But widget views !== dom elements.  For my usecase, for example, widget 
views are Three.js objects.  And you can certainly have the same 
three.js object in multiple places in the scene graph.  For example, I 
want the same geometry object with several different kinds of material.

> Conceptually, I think we *do* want multiple views. Each view maps onto
> one place in the page where the widget is displayed. Each of those
> instances needs to be able to handle its own events, etc. For example,
> only one instance of the view can have focus at a time or accept
> keyboard input.
> Am I missing something?

I thought we were transitioning to having multiple widgets for display 
in different places that were linked together.  The "view" is really the 
python instance+backbone model+backbone view.  If you want a widget in 
multiple places, create multiple widgets and link them together.  The 
model is simpler.  If you want multiple views in javascript for the same 
model/python instance, then you really probably ought to expose those 
views on the python side with full python view classes.



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