Refactor contour styling to fix MatplotlibDeprecationWarning

[levi178u]

Purpose of PR?:

Fixes #2728
Changes done:

• Fixed deprecated use of .collections in contour plotting for matplotlib>=3.8 to prevent MatplotlibDeprecationWarning.
• Updated _plot_style() to use ContourSet.set_path_effects() directly.
• updated contour styling files of styles and plots.
• Verified existing plot behavior remains unchanged by test cases passing.

[levi178u]

@ReimarBauer pls review this PR

[ReimarBauer]

By which pytest do you verify existing plot behavior remains unchanged?

[levi178u]

By which pytest do you verify existing plot behavior remains unchanged?

By test_mss_plot_driver.py in _test_mswms I check if it passed all the test cases for the cases of plots in that way i verified as it passed all test cases

[matrss]

Your proposed changes still use the collections attribute, which as stated in the issue is deprecated. How is this supposed to fix the issue?

[levi178u]

Your proposed changes still use the collections attribute, which as stated in the issue is deprecated. How is this supposed to fix the issue?

yes u r right, my aim was to suppress the deprecation warning by reducing the dependence on .collections , here i have applied styling using path_effects at plot creation time. i had read the docs and found that currently matplotlib doesnt support passing path_effects directly to plt.contour() without accessing .collections, so i did this

[levi178u]

Mentors, we can follow an alternate method in which we don't rely on .collections completely. Here i referred that https://matplotlib.org/stable/api/collections_api.html#matplotlib.collections.PathCollection , we can use Linecollection or Pathcollection but it has a limitation that we can’t pass path_effects directly to ax.contour() or plt.contour() in this scenario.

[matrss]

I don't understand why you focus on not being able to pass path_effects to .contour, there is no need to do that. Please read the documentation for this API change in matplotlib: https://matplotlib.org/stable/api/prev_api_changes/api_changes_3.8.0.html#contourset-is-now-a-single-collection. Following this it should now be possible to call the .set_path_effects method on the ContourSet object directly.

[levi178u]

I don't understand why you focus on not being able to pass path_effects to .contour, there is no need to do that. Please read the documentation for this API change in matplotlib: https://matplotlib.org/stable/api/prev_api_changes/api_changes_3.8.0.html#contourset-is-now-a-single-collection. Following this it should now be possible to call the .set_path_effects method on the ContourSet object directly.

Thnx @matrss, I missed this part , I'll make the changes for the same by direct calling instead of passing,

[levi178u]

@matrss pls review the changes

[levi178u]

@matrss pls review the changes

[levi178u]

@matrss ,@joernu76 pls review

[levi178u]

@mentors need review for this PR pls