Feature/outline color for labels

[MeyerBender]

This addresses two previous issues with rendering labels:

1. Users can now set the color of the outline with the outline_color argument, similar to how they could in render_shapes(), see Ability to change color of the border of labels #462
2. Fixes color leak when plotting outlines only in render_labels, see Color leak when outline_alpha=1 and full_alpha=0 #461

Example code to see both changes in action:

import spatialdata as sd
import spatialdata_plot
from spatialdata.datasets import blobs

sdata = blobs()
sdata.pl.render_images('blobs_image', channel=0).pl.render_labels('blobs_labels', outline_alpha=1, fill_alpha=0, outline_color='white').pl.show()

[MeyerBender]

@timtreis Naive question but I can't find where to download the artifacts to fix the tests, is this a permission issue or am I missing something?

[LucaMarconato]

@MeyerBender artifacts can be downloaded from the Actions page, for instance here: https://github.com/scverse/spatialdata-plot/actions/runs/20439596502?pr=526

Please find more info here: https://github.com/scverse/spatialdata-plot/blob/main/docs/contributing.md. Let me know if some questions are still open and not covered by the contribution guide.

[MeyerBender]

Thanks @LucaMarconato! With my current implementation, it is only possible to specify a colorlike, but not a feature (like "area"). I think it would be good to merge #497 first, and then add my code on top of that.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.96%. Comparing base (4fe68de) to head (9485058).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #525      +/-   ##
==========================================
- Coverage   84.01%   83.96%   -0.05%     
==========================================
  Files           9        9              
  Lines        2608     2626      +18     
==========================================
+ Hits         2191     2205      +14     
- Misses        417      421       +4     

Files with missing lines	Coverage Δ
src/spatialdata_plot/pl/basic.py	91.63% <ø> (ø)
src/spatialdata_plot/pl/render.py	89.01% <100.00%> (+0.06%)	⬆️
src/spatialdata_plot/pl/render_params.py	90.35% <100.00%> (+0.04%)	⬆️
src/spatialdata_plot/pl/utils.py	79.24% <100.00%> (-0.08%)	⬇️

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[timtreis]

Hey @MeyerBender, I merged #497 and updated your PR accordingly. Could you verify that it matches the behaviour you intended?

[MeyerBender]

Hi @timtreis, this looks great, thanks a lot! As a sidenote, running pl.render_labels('blobs_labels', outline_alpha=1) without specifying a color sets a random color for each cell, which might be confusing. I agree with your comment in the other PR that using just one color would be more sensible in that case.