Canavandl/1441 colorbar

[canavandl]

(ninja edit) Note: this branch is branched from #4851 and should only be merged after the parent.

Proof-of-concept color bar

• issues: fixes Colorbar Axis #1441
• tests added / passed
• release document entry (if new feature or API change)

The code is a mess (lots of copy pasta from axis.coffee and hardcoded values), but serves to generate a POC color bar. (this uses a LogColorMapper, but Linear looks identical except for the tick spacing).

[canavandl]

Apart from code issues (including the floating tick above the color bar), are there any visual components that I'm missing. Specifically:

• Should a colorbar have a title somewhere? Above or to the right of the ticks?
  • Maybe on top? I'm not sure it's necessary though.
• I could enclose the entire color bar in a rect with configurable fill props. Is that worthwhile?
  • I think I'm +1 on this and will try to prototype. Something with some nice padding around the non-scale side of the image.
• Anything else?

[canavandl]

POC bounding rect of color bar (default color would probably be None and padding would be tweaked):

[birdsarah]

Should a colorbar have a title somewhere? Above or to the right of the ticks?

Yes (optionally) - if the ticks are on the right, the default position should be on the top left - left aligned with the actual color bar (not aligned with the text)

I could enclose the entire color bar in a rect with configurable fill props. Is that worthwhile?

I think it's fine to leave that for later

Anything else?

I think this should have the same padding, margin etc properties as legend, specifically as proposed by @almarklein here: #4526 - so the same properties as legend will have!

[canavandl]

Now the location/orientation properties are correctly implemented (though still ugly):

[mattpap]

This change needs an explanation (should have been done in the initial commit). There might be unforeseen consequences of this change across code base. This is also why one should refrain from using "refactoring" near such changes, as this changes both APIs and functionality.

[canavandl]

The refactoring of Legend into a subclass of GuideRenderer is isolated in PR #4851 and this branch is merged off of the #4851 parent. I should have mentioned that in the initial comment (I'll add it now).

[canavandl]

superceded by #4931