Redraw ChartMPL on Plotter render

[dcbr]

Overview

As requested in #3380 this PR adds functionality to automatically redraw ChartMPL charts whenever the Plotter.update() method is called. Furthermore, a bug in the chart's _resize method is fixed. Resolves #3380.

Details

• Adds a redraw_on_render property for ChartMPL (default True), which enables automatic redrawing of these charts when the Plotter.render() method is called. To support this feature, extra on_plotter_render methods to the Renderer and Renderers classes are needed to discern between a manual call to Plotter.render and manual/automatic calls to Renderer.Render (which invoke VTK StartEvent, also used by charts).
• Previously the logic in the _resize method of charts used exact comparisons of floats, which lead to unnecessary resizings (and redrawings) of charts. This PR converts all current and target dimensions to integers to resolve this bug.

[banesullivan]

LGTM... the general updates to the BasePlotter look good to me (calling update() on the renderers when BasePlotter.update() is called).

Otherwise, I trust you, @dcbr, as I'm totally unfamiliar with what's going on with the charting

[codecov]

Codecov Report

Merging #3731 (e64bd35) into main (3db44d7) will increase coverage by 0.16%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #3731      +/-   ##
==========================================
+ Coverage   93.99%   94.16%   +0.16%     
==========================================
  Files          82       86       +4     
  Lines       18553    18906     +353     
==========================================
+ Hits        17439    17802     +363     
+ Misses       1114     1104      -10     

[dcbr]

Alright, I tested locally on Windows, but I'll add a test tomorrow to improve coverage as well :)

[dcbr]

I added the test, ready for review (again) if everything turns green :)

[akaszynski]

I added the test, ready for review (again) if everything turns green :)

Failures will be fixed in #3736 and #3737.

[banesullivan]

I know I gave this an initial approval but now I have some counter thoughts on adding an update() method to the Renderer class - IMO, this should be in the render() calls

[dcbr]

Hmm yea I thought of adding it to the render() method instead. The reason I chose not to, is because render is already called in various other plotting methods that are unrelated to charts (and thus cause unnecessary overhead of redrawing the ChartMPL figures).
Maybe a workable middleground is to split the rendering step (internally) in two parts: render_viewport for rendering the 3D parts (and calling vtkRenderer.Render) and render_scene for rendering the 2D parts (and updating ChartMPL figures). The existing calls to render from other plotting methods can then be converted to render_viewport such that Charts are not impacted by them. And the existing render method then just calls both render_viewport and render_scene. What do you think?

[dcbr]

Maybe for now I can just move it to the render method and if we ever want to improve performance (or in case there are complaints), we can still do this split later.

[banesullivan]

Overall, I'm happy with this! but I think Renderer.render() needs to call self.Render() too

[banesullivan]

on_plotter_render() is a good choice. LGTM!