Thanks for this effort!

At over 2000 lines of code this is an insanely large PR. That also makes it difficult to review.

• Is this PR in it's finished state? Or more a proof of concept?
• How large would a minimum implementation be?
• What's the quickest way for a reviewer to validate/reproduce the desired behavior?
• Have you investigated the test failures?

Hello,

--> This PR is a finished implementation, not just a proof of concept. The large diff is mainly due to the Solara demo and documentation, the core backend changes are much smaller.
--> A minimal implementation (core icon rendering in Altair) would be under 300 lines, excluding the demo and docs.
--> To quickly validate: run [solara run mesa/visualization/solara_viz_icon.py]( for the interactive demo, or use the new [icon] key in agent portrayals with the Altair backend.
--> All tests pass except for one (test_call_space_drawer in [test_solara_viz.py]. I will investigate and resolve this issue. All other tests are passing. Let me know if you’d prefer a split PR (core backend vs. demo/docs). What do you think?

Thanks for the quick and detailed reply.

Let me know if you’d prefer a split PR

Yes please. Target a "production ready" PR, so production code + essential documentation.

What we often do when integrating a new feature, is updating one example model in mesa/examples. That makes sure the feature is directly tested and documented though code.

I did pip install cairosvg (on Windows), but I need also a non-pip dependency?

OSError: no library called "cairo-2" was found
no library called "cairo" was found
no library called "libcairo-2" was found
cannot load library 'libcairo.so.2': error 0x7e.  Additionally, ctypes.util.find_library() did not manage to locate a library called 'libcairo.so.2'
cannot load library 'libcairo.2.dylib': error 0x7e.  Additionally, ctypes.util.find_library() did not manage to locate a library called 'libcairo.2.dylib'
cannot load library 'libcairo-2.dll': error 0x7e.  Additionally, ctypes.util.find_library() did not manage to locate a library called 'libcairo-2.dll'

Adding a new dependency (cairosvg) is not ideal but might be proportional, but I don't think asking users to install anything not-pip is.

Thank you for the feedback .
I’ll split the PR as suggested: one for production code and essential documentation only. I’ll also update one example model in [mesa/examples] to demonstrate and test the new feature.

Regarding the cairosvg dependency: I agree that requiring users to install non-pip system libraries (like libcairo) is not ideal. I’ll investigate alternatives to avoid this requirement.