Interactive scalar bars

[banesullivan]

The scalar bar code needs to be updated to give users more control over where to place scalar bars and whether or not they should be present.

What should be the default behavior of the scalar bars?

• Should a scalar bar always be added when adding a mesh?
• Should it be interactive by default?

Todo:

• add scalar bar widgets for interactivity.
• add an option to not display a scalar bar when adding a mesh with a scalar array.
• make a better scheme for automatically placing new scalar bars (interactive and non-interactive) Maybe down the road. Use interactive scalar bars to place where desired for now
• add a way for vertical scalar bars to have vertical text Requires a lot of effort... maybe down the road.

[akaszynski]

I think adding a scalar bar for each mesh would make the render window cluttered. We might want to limit the number of "automatic" scalar bars to two. They probably should be automatic if there mesh has scalars.

[banesullivan]

I think adding a scalar bar for each mesh would make the render window cluttered.

Agreed. A while back I added code so that if n meshes are added and plotted with a scalar array of the same name or stitle then they will both share a single scalar bar and the mapping will be updated to the full data range across those n datasets. Note that this can get buggy if the cmaps are not the same.

We might want to limit the number of "automatic" scalar bars to two.

To implement this, should we check how many scalar bars are present and if there are two, then only add the scalar bar if the user explicitly says to: show_scalar_bar=True and make default parameter for show_scalar_bar=None

[codecov]

Codecov Report

Merging #79 into master will decrease coverage by 0.17%.
The diff coverage is 43.75%.

@@            Coverage Diff             @@
##           master      #79      +/-   ##
==========================================
- Coverage   88.43%   88.25%   -0.18%     
==========================================
  Files          16       16              
  Lines        4184     4198      +14     
==========================================
+ Hits         3700     3705       +5     
- Misses        484      493       +9

Impacted Files	Coverage Δ
vtki/plotting.py	83.16% <43.75%> (-0.62%)	⬇️

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[banesullivan]

FYI: https://discourse.vtk.org/t/move-a-scalar-bar-with-pyq5-and-python3-5/289