Update Colorizer/ColorizingArtist to work with MultiNorm by trygvrad · Pull Request #30511 · matplotlib/matplotlib

trygvrad · 2025-09-03T17:01:30Z

EDIT: closes #30511

This PR continues the work of #28658 and #28454, #29876, aiming to close #14168. (Feature request: Bivariate colormapping)

This PR allows Colorizer and ColorizingArtist to work with MultiNorm and BivarColormap and MultivarColormap

i.e. this PR will allow:

import matplotlib.pyplot as plt
import numpy as np
import matplotlib as mpl
a = np.arange(12).reshape(3,4)
b = np.arange(12).reshape(4,3).T

norm = mpl.colors.Normalize(vmin=0, vmax=11)
col = mpl.colorizer.Colorizer(cmap='BiOrangeBlue', norm=[norm, norm])

plt.imshow(col.to_rgba((a, b)))

Features not included in this PR:

Exposes the functionality provided by MultiNorm together with BivarColormap and MultivarColormap to the plotting functions axes.imshow(...), axes.pcolor(...), and axes.pcolormesh(...)`
fig.colorbar() equivalents for BivarColormap and MultivarColormap
Examples in the docs

PR checklist

new and changed code is tested

lib/matplotlib/cbook.py

lib/matplotlib/colorizer.py

lib/matplotlib/tests/test_colors.py

lib/matplotlib/colorizer.py

trygvrad · 2025-09-04T23:40:54Z

Thank you for the feedback @QuLogic and apologies for my sloppy mistakes :)

@QuLogic

improved testing for colorizer+multinorm Apply suggestions from code review Co-authored-by: Elliott Sales de Andrade <quantum.analyst@gmail.com> updates based on feedback from @QuLogic

lib/matplotlib/colorizer.py

lib/matplotlib/tests/test_colors.py

lib/matplotlib/colorizer.py

QuLogic

As I mentioned on the call, I think this looks okay from a low-level point-of-view, but I am at this point uncertain as to the high-level status. I hope someone more familiar with the current state can confirm.

PS, @trygvrad if you have some time to pop in to the call, it would be good to just re-iterate the current state succinctly, as I'm not sure everyone is up-to-speed right now.

story645

Sorry it took so long to get to this.

story645 · 2025-09-18T19:34:20Z

lib/matplotlib/colorizer.py

            if norm and (xx.max() > 1 or xx.min() < 0):
                raise ValueError("Floating point image RGB values "
-                                 "must be in the 0..1 range.")
+                                 "must be in the 0..1 range")


Suggested change

"must be in the 0..1 range")

"must be in the [0,1] range")

teenyist nit but I find interval notation clearer

FYI: This required a change to an existing test test_colors.py→test_scalarmappable_nan_to_rgba(bytes) which had a regex for the string '0..1 range'

lib/matplotlib/colorizer.py

story645 · 2025-10-10T00:44:47Z

lib/matplotlib/colorizer.py

+    elif n_components == 2:
+        raise ValueError("Invalid data entry for multivariate data. The data"
+                         " must contain complex numbers, or have a first dimension 2,"
+                         " or be of a dtype with 2 fields")


I'm not following what 2 components means in this context

We had a discussion when declaring MultiNorm that we should refer to the different channels/variates as components, so MultiNorm has the property n_components which is the number of channels/variates/components.

In the following example it would be 2, because the colormap supports 2 channels, and we provide 2 datasets.

plt.imshow((A, B), cmap='BiOrangeBlue')

Thanks! Sorry for forgetting this. :/

trygvrad · 2025-10-11T17:55:23Z

Sorry it took so long to get to this.

No worries, thank you for getting around to it :)

Co-authored-by: hannah <story645@gmail.com>

story645

Comments but definitely not blocking, will leave unmerged for a day but they can also be addressed on followup. Thanks for all your patience and persistence.

lib/matplotlib/colorizer.py

story645 · 2025-10-24T18:53:43Z

lib/matplotlib/colorizer.py

+    elif n_components == 2:
+        raise ValueError("Invalid data entry for multivariate data. The data"
+                         " must contain complex numbers, or have a first dimension 2,"
+                         " or be of a dtype with 2 fields")


Thanks! Sorry for forgetting this. :/

trygvrad · 2025-10-29T20:22:56Z

@story645 I added the test we discussed, please take a look at the last commit :)

lib/matplotlib/colorizer.py

story645 · 2025-10-30T19:28:50Z

doc build failures seem to be intersphinx related

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

github-actions bot added the topic: color/color & colormaps label Sep 3, 2025

trygvrad force-pushed the colorizer-multinorm branch from 77bc51a to 9044189 Compare September 3, 2025 17:20

QuLogic added this to Bivariate and Multivariate Colormapping Sep 3, 2025

QuLogic reviewed Sep 4, 2025

View reviewed changes

github-actions bot added the status: needs rebase label Sep 4, 2025

trygvrad force-pushed the colorizer-multinorm branch from 9b9aaf3 to 525314e Compare September 4, 2025 23:35

Update Colorizer/ColorizingArtist to work with MultiNorm

23fb63c

improved testing for colorizer+multinorm Apply suggestions from code review Co-authored-by: Elliott Sales de Andrade <quantum.analyst@gmail.com> updates based on feedback from @QuLogic

trygvrad force-pushed the colorizer-multinorm branch from 525314e to 23fb63c Compare September 8, 2025 07:20

github-actions bot removed the status: needs rebase label Sep 8, 2025

trygvrad moved this to In Progress in Bivariate and Multivariate Colormapping Sep 8, 2025

This was referenced Sep 8, 2025

Preparations for multivariate plotting #29877

Closed

Imshow, pcolor and pcolormesh with Bivariate and Multivariate colormaps #30526

Open

QuLogic reviewed Sep 9, 2025

View reviewed changes

Updates based on feedback from @QuLogic

d5c43e0

trygvrad force-pushed the colorizer-multinorm branch from eb37db8 to d5c43e0 Compare September 11, 2025 07:52

QuLogic approved these changes Sep 11, 2025

View reviewed changes

trygvrad mentioned this pull request Sep 24, 2025

Multivar imshow #30597

Open

2 tasks

story645 reviewed Oct 10, 2025

View reviewed changes

Apply suggestions from code review

9409d4c

Co-authored-by: hannah <story645@gmail.com>

trygvrad force-pushed the colorizer-multinorm branch from cf9296d to 9409d4c Compare October 11, 2025 18:42

story645 approved these changes Oct 24, 2025

View reviewed changes

QuLogic reviewed Oct 29, 2025

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lib/matplotlib/colorizer.py Outdated Show resolved Hide resolved

Added test for cmap.n_variates == 0 in colorizer

6934853

trygvrad force-pushed the colorizer-multinorm branch from 8745b81 to 6934853 Compare October 29, 2025 20:41

story645 added this to the v3.11.0 milestone Oct 30, 2025

story645 merged commit 78617c1 into matplotlib:main Oct 30, 2025
35 of 39 checks passed

github-project-automation bot moved this from In Progress to Done in Bivariate and Multivariate Colormapping Oct 30, 2025

andreas16700 added a commit to andreas16700/matplotlib that referenced this pull request Jan 28, 2026

Run 14: Match upstream 78617c1 (PR matplotlib#30511)

4085628

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

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trygvrad commented Sep 3, 2025 •

edited

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