Add a registry for color sequences by timhoffm · Pull Request #22387 · matplotlib/matplotlib · GitHub

Color sequences are simply lists of colors, that we store by name in
a registry. The registry is modelled similar to the ColormapRegistry
to 1) support immutable builtin color sequences and 2) to return copies
so that one cannot mess with the global definition of the color sequence
through an obtained instance.
Note that some details of ColormapRegistry are different and we need
different docstrings so that it's easier to have a separate class and not try
to factor out some common aspects in a base class.

For now, I've made the sequences used for ListedColormaps available
as builtin sequences, but that's open for discussion.

More usage documentation should be added in the color examples and/or
tutorials, but I'll wait with that till after the general approval of
the structure and API. One common use case will be

plt.rc_params['axes.prop_cycle'] = plt.cycler(color=plt.color_sequences['Pastel1')

Should we include the list of known keys here?

So these are essentially colour palettes? Should they be named colour palettes? And if they are colour palettes, how does that jive with colour palettes in seaborn?

Yes maybe we should hoist the palette framework to matplotlib? Then in the context of this request we could add named_palette to take the name of a sequential colormap?

I think it may be confusing for us to have a parallel api to seaborn, so if we go a different way we should be very explicit about the differences.

seaborn.color_palette() is more a color sequence generator that a registry. That's much more than I had in mind, but we can discuss whether we want that functionality.

seaborn.color_palette(palette=None, n_colors=None, desat=None, as_cmap=False)

Apart from (1) returning some named palettes, it can create a palette:

by (2) sampling a matplotlib colormap
by (3) sampling from ‘husl’ or ‘hls’, cubehelix system (less configurable versions of the functions husl_palette, hls_palette, cubehelix_palette)
by (4) lightening or darkening a base color (see also light_palette, dark_palette)

(5) Additionally, one can choose the number of colors. This is quite nice.

(6) Additionally, one can desaturate the colors. This feels a bit much for the function. One could alternatively have a function desaturate(color_palette(...)) or make a slightly fancier list-like object, so that you can do color_palette(...).desaturate(...).

(7) Additionally, one can turn each of the palettes into a Colormap.

colormap -> color sequence

Moving to draft until we have decided whether and how far we want to go the seaborn way.

Next actions:

@timhoffm have a closer look at seaborn and come up with a proposal
Discussion in dev cal

Talked about this on today's call: https://hackmd.io/jd_7FjxNQ4y7XgNknvmvGQ?view#color-registry

The consensus was

keep the sequence registry simple as a mapping of str -> sequence of colors
do not try to re-use the name palettes to avoid confusion with seaborn
as a separate question add a (stateless) function for fabricating color sequences from simple input (in the spirit of seaborn.color_palette()).

The existing PR should comply with everything we discussed in the dev call. Marking as ready-to-review.

The doc failures are relevant.

Do we want to have __contains__ to check for registered sequences?

__contains__ is mixed in through the use of collections.abc.Mapping
See https://docs.python.org/3/library/collections.abc.html#collections-abstract-base-classes

Ah, I missed the class inheritance.

Color sequences are simply lists of colors, that we store by name in a registry. The registry is modelled similar to the ColormapRegistry to 1) support immutable builtin color sequences and 2) to return copies so that one cannot mess with the global definition of the color sequence through an obtained instance. For now, I've made the sequences used for `ListedColormap`s available as builtin sequences, but that's open for discussion. More usage documentation should be added in the color examples and/or tutorials, but I'll wait with that till after the general approval of the structure and API. One common use case will be ``` plt.rc_params['axes.prop_cycle'] = plt.cycler(color=plt.color_sequences['Pastel1') ``` Co-authored-by: Elliott Sales de Andrade <quantum.analyst@gmail.com>

timhoffm added the topic: color/color & colormaps label Feb 3, 2022

timhoffm added this to the v3.6.0 milestone Feb 3, 2022

timhoffm mentioned this pull request Feb 3, 2022

Color blind-friendly default color cycle #9460

Open

tacaswell approved these changes Feb 4, 2022

View reviewed changes

tacaswell reviewed Feb 4, 2022

View reviewed changes

timhoffm added the status: needs comment/discussion needs consensus on next step label Feb 4, 2022

mpetroff reviewed Feb 5, 2022

View reviewed changes

timhoffm marked this pull request as draft February 13, 2022 22:35

timhoffm marked this pull request as ready for review February 24, 2022 23:09

timhoffm force-pushed the color-sequences branch from fef03f9 to e5d6be8 Compare February 24, 2022 23:10

timhoffm force-pushed the color-sequences branch from e5d6be8 to 3aeaa2d Compare March 2, 2022 23:49

timhoffm removed the status: needs comment/discussion needs consensus on next step label Mar 3, 2022

QuLogic reviewed May 5, 2022

View reviewed changes

Comment thread doc/api/colors_api.rst Outdated

Comment thread lib/matplotlib/colors.py Outdated

Comment thread lib/matplotlib/tests/test_colors.py Outdated

timhoffm force-pushed the color-sequences branch 2 times, most recently from 92dd83c to 3128f0d Compare May 5, 2022 20:24

timhoffm force-pushed the color-sequences branch from 3128f0d to 0abe0ce Compare May 5, 2022 21:30

QuLogic merged commit 6997192 into matplotlib:main May 5, 2022

timhoffm deleted the color-sequences branch May 6, 2022 06:57

QuLogic mentioned this pull request Sep 9, 2022

Consolidate release notes for 3.6 #23814

Merged

2 tasks done

+                      try:
+                          return list(self._color_sequences[item])
+                      except KeyError:
+                          raise KeyError(f"{item!r} is not a known color sequence name")

+                      """
+                      Register a new color sequence.
+                      The colormap registry stores a copy of the given *color_list*, so that

Add a registry for color sequences by timhoffm · Pull Request #22387 · matplotlib/matplotlib · GitHub

Repository navigation

Add a registry for color sequences - #22387

Add a registry for color sequences#22387QuLogic merged 1 commit intomatplotlib:mainmatplotlib/matplotlib:mainfrom timhoffm:color-sequencestimhoffm/matplotlib:color-sequencesCopy head branch name to clipboard

Conversation

timhoffm commented Feb 3, 2022

Uh oh!

tacaswell Feb 4, 2022

Choose a reason for hiding this comment

Uh oh!

QuLogic commented Feb 4, 2022

Uh oh!

jklymak commented Feb 4, 2022

Uh oh!

timhoffm commented Feb 4, 2022

Uh oh!

mpetroff Feb 5, 2022

Choose a reason for hiding this comment

Uh oh!

timhoffm commented Feb 13, 2022 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

tacaswell commented Feb 24, 2022

Uh oh!

timhoffm commented Feb 24, 2022

Uh oh!

QuLogic commented Mar 1, 2022

Uh oh!

QuLogic left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

timhoffm commented May 5, 2022

Uh oh!

QuLogic commented May 5, 2022

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

5 participants

Add a registry for color sequences#22387
QuLogic merged 1 commit into
matplotlib:mainfrom
timhoffm:color-sequences

timhoffm commented Feb 13, 2022 •
edited
Loading