Make colors configurable

[dhaitz]

Hi!

Could you make the colors configurable? I like the idea of being colorblind-friendly; unfortunately on some projectors the palette colors are indistinguishable.

Thanks and cheers

[parrt]

good idea!

[Ashafix]

@dhaitz : How should the configuration look like in your opinion? Global or per function call?

As far as I could see from the code, the colors are currently just global constants which can be overwritten, e.g. dtreeviz.trees.GREY = "#ff0000" and you get red labels.

Probably the easiests way would be to have a global dictionary which stores the colors and can be overwritten for customization, e.g. COLORS = {'label': GREY, ', 'title': BLACK}

@parrt : Any preferences?

from sklearn import tree
from sklearn.datasets import load_boston
import dtreeviz.trees

dtreeviz.trees.GREY = "#ff0000"

regr = tree.DecisionTreeRegressor(max_depth=2)
boston = load_boston()
regr.fit(boston.data, boston.target)

viz = dtreeviz.trees.dtreeviz(regr, boston.data, boston.target, target_name='price', feature_names=boston.feature_names)
              
viz.view()

[parrt]

I think some kind of argument would be better than tweaking the globals.

[dhaitz]

@Ashafix , @parrt : Maybe something like this in dtreeviz/trees.py?

GREY = "#ff0000"
...
COLORS = {'label': GREY, ', 'title': BLACK}

def dtreeviz(..., 
             colors: dict = None
             ):

    if colors is None:  # fall back to module-level default colors
        colors = COLORS

[parrt]

or just colors:dict=COLORS?

[dhaitz]

@parrt ah yes, of course this is the simple and straightforward solution.

Another approach would be:

if colors is None:
    colors = dict(COLORS, **colors)

which would allow you to overwrite only certain keys in the colors argument and use the defaults from COLORS for all others.

[Ashafix]

Please have a look at Ashafix@ee02d0f
and let me know if it's the right direction.

• Each function has an optional parameter colors which is a dictionary, each dictionary key can overwrite a default value.
• The colors are stored in colors.py allowing easy global modification
• Having a new optional parameter should allow re-use of all previous scripts which use dtreeviz
• change_colors.py demonstrates the effects with a few examples
• "tested" on Windows 10 and Ubuntu 16.04

[parrt]

@Ashafix Looks pretty good! widespread changes but it's adding a lot of control to the look of the plots. could you make a PR? I'm wondering if colors.py should be a separate file or included... thoughts?

[Ashafix]

@parrt : Thanks for the quick feedback! Personal opinion, I'd prefer a separate file for the colors/configuration, but not my library.

I will test and document all parameters and then create a PR.

[parrt]

sounds great. does extra file cause any package weirdness for users? if invisible, let's factor out into colors.py :)

[mattharrison]

While you are on colors, could you do font's as well :) (Ie make them configurable)

[Ashafix]

@mattharrison : one PR at a time...