Add support for interactive mode on Matplotlib

[philippjfr]

Adds support for interactive Matplotlib plots based on ipympl.

[codecov]

Codecov Report

Merging #1469 into master will decrease coverage by 0.70%.
The diff coverage is 40.84%.

@@            Coverage Diff             @@
##           master    #1469      +/-   ##
==========================================
- Coverage   86.44%   85.74%   -0.71%     
==========================================
  Files         138      138              
  Lines       15361    15618     +257     
==========================================
+ Hits        13279    13391     +112     
- Misses       2082     2227     +145     

Impacted Files	Coverage Δ
setup.py	0.00% <ø> (ø)
panel/pane/ipywidget.py	45.71% <18.18%> (-1.17%)	⬇️
panel/pane/plot.py	54.33% <29.78%> (-9.45%)	⬇️
panel/io/notebook.py	58.64% <100.00%> (ø)
panel/pane/ace.py	90.90% <100.00%> (ø)
panel/pane/base.py	89.55% <100.00%> (ø)
panel/pane/deckgl.py	73.52% <100.00%> (ø)
panel/pane/markup.py	97.07% <100.00%> (ø)
panel/pane/plotly.py	88.88% <100.00%> (ø)
panel/pane/vega.py	79.50% <100.00%> (ø)
... and 4 more

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[MarcSkovMadsen]

I thought the ipywidgets where costly to load and as such native bokeh/ panel implementations where preferred?

[jbednar]

Sure, but there are plenty of plots available from Matplotlib not available anywhere else, plus some people just prefer Matplotlib. Panel has no opinion about what plotting library you use, though of course each one comes with tradeoffs...

[philippjfr]

Also this is entirely optional, I'm just giving users access to this capability.

[MarcSkovMadsen]

Its not that i dont like. I do. I’m just trying to understand when a native implementation is required and when ipywidgets version Can be used.

There Probably are a lot of things that Can be done via ipywidgets.

Ivuetify for example.

Would it be ok to give users easy access to these in Panel via Param or would it be something you can do but really should not do? Instead bokeh models should be built?

[jbednar]

Sure. I'd say that there is a large class of things that can very easily be made available to Panel users in some usable form. Some of those could be made much more performant if someone wants to invest time and energy into them, but if even the easily obtained version is already usable in many cases, why not? I'd only invest in making a highly optimized special version if it's really needed; in the meantime it's great that more things just work!

[mcrees]

Hi,
I have been experiencing issues with interactive Matplotlib panes.

First - the interactive options are not displaying properly. All the functionality is working but the icons are not displaying correctly:

Second - Sizing to fit spaces does not seem to function well with interactive mode. When interactive mode is False, sizing works as expected (scaling or stretching).

I'm using PyCharm, files are .py & panel v 0.11.3

Not sure if this is the best place to post.
Thanks for the good work

[jbednar]

So that we can keep track of to-do items, please open two separate issues, each listing the relevant software versions and describing that specific problem. Comments on closed or merged PRs are very likely to get overlooked!