remove plotly/colors.py in favour of utils

[Kully]

Since figure_factory is 100% of the code that is using colors.py, it makes more sense to move the colors.py that are not in plotly.figure_factory/utils.py in there.

In favour of PR: #878

TODOs for this PR:

• moved all colors.py functions to figure_factory.utils.py
• redirect all reference to colors over to utils
• add tests for all utils.py functions

For another PR:

• fix how _scatter, _gantt, _bullet (and maybe others) use the plotly color scales. Right now, the modules are built such that if a user inputs Viridis for instance, the color functions will return just a list of the colors found in the Viridis colorscale, but without the appropriate colorscale numbers to indicate how the interpolation works between each color (i.e. these modules linearly interpolate between the colors of the Plotly colorscales)

[Kully]

ready for a review @jonmmease

[jonmmease]

Thanks for working on this cleanup @Kully, I'll look it over in more detail soon.

In the meantime, I'm a little worried about deleting plotly/colors.py in case people have found it and are relying on functions in there. Can you add a plotly/colors.py file back in that just imports all of the public functions/variables from their new locations?

[Kully]

Can you add a plotly/colors.py file back in that just imports all of the public functions/variables from their new locations?

Sure!

[Kully]

Can you add a plotly/colors.py file back in that just imports all of the public functions/variables from their new locations?

The issue I'm running into is that figure_factory relies on a numpy import, but none of the functions that colors.py is using does.

I haven't found a way to slickly import only the figure_factory.utils without grabbing the rest of the modules in the tree. And I don't want to change the hierarchy structure of the repo.

Any suggestions on how to proceed? Perhaps a 1-liner of python code in colors.py with a comment saying that colors is being depreciated in the next plotly version.

[jonmmease]

@Kully, I see what you mean about the numpy dependency. Let's leave the plotly/colors.py where it is then for now. Also, I don't see any fundamental reason why we wouldn't use these functions from the core (non figure factory) code at some point.

If we leave colors.py where it is, are there other things from the PR that you want to keep?

[Kully]

Let's leave the plotly/colors.py where it is then for now.

By this I understand you mean to leave functions defined directly from plotly/colors.py rather than importing from figure_factory

I don't see any fundamental reason why we wouldn't use these functions from the core

I agree with this too.

If we leave colors.py where it is, are there other things from the PR that you want to keep?

There are duplicate functions in here that I removed a few commits above. I think we should for sure keep the duplicate functions removed.

[Kully]

closing in favor of #1301