Using ipywidgets with standalone cell view/output

[krassowski]

Problem

It's currently hard to use ipywidgets outside of existing notebook and console widgets. It should not be.

Proposed Solution

Expose registerWidgetHandler? Generalize it to take Notebook | Console | IDisposable argument?

ipywidgets/python/jupyterlab_widgets/src/plugin.ts

Lines 168 to 174 in b24fa6b

	async function registerWidgetHandler(
	content: Notebook | CodeConsole,
	sessionContext: ISessionContext,
	rendermime: IRenderMimeRegistry,
	renderers: IterableIterator<WidgetRenderer>,
	widgetManagerFactory: () => WidgetManager | KernelWidgetManager
	): Promise<DisposableDelegate> {

Additional context

Related to jupyterlab/jupyterlab#16227

[krassowski]

It is pretty easy to pretend that we have a console and use registerConsoleWidgetManager. It goes like:

registerConsoleWidgetManager(
  {console: {
    sessionContext,
    rendermime,
    disposed: outputArea.disposed
  }} as any,
  chain(widgetOutputs())
)

[martinRenou]

Agreed!

I understand #3922 would go in that direction. Though it may be quite breaking (I only assume, haven't reviewed yet). I'm not sure I like the idea of breaking the APIs, ipywidgets 8 was already quite disruptive.

[fleming79]

I've been working on the PR jtpio/ipylab#135 for ipylab that uses #3922.

For a per-kernel widget manager the following line enables Ipywidgets for a kernel.

new KernelWidgetManager(sessionContext.session.kernel, rendermime as any);

rendermime is optional and would default to the global rendermime if omitted.

It is foreseeable that widgets could be automatically enabled for any Python kernel started or registered in Jupyterlab.

The screenshots below demonstrate the capabilities of ipylab combined with the per-kernel widget manager.

• starting kernels
• creating launcher buttons
• adding widgets to the main area
• adding widgets to the side area

I've been using these new features for months in Jupyterlab 4 without major issue. I'm no expert in Jupyterlab or Ipywidgets and would appreciate guidance / collaboration from an expert.

Create launchers

Control of Jupyterlab and adding widgets to the main area