legend_key not impacting theme

[darothen]

Yesterday I wrote a blog post creating a standard visualization from my research in plotnine; the final plot / code is available here. Everything works great, but there's one thing that I couldn't get to work: the legend_key element I passed to the final call to theme() didn't actually change the plot aesthetics. My understanding is that the way I wrote the code, i.e.

legend_key=element_rect(fill='white', color='white')

should've made each of the line marker glyphs in the legend have a white background. But, they remained grey. Is this a mis-understanding on my part, or a glitch?

[has2k1]

I saw the post and immediately noticed the grey background in the legend keys. First, the background of the keys defaults to the plot background, but since theme_seaborn is entirely specified through rcParams and not theme elements there is a glitch. I think having white as a default will lessen the impact.

This

 + theme_seaborn(style='ticks', context='talk', font_scale=0.75)
 + theme(legend_key=element_rect(fill='white', color='white'))

should work. Did you add theme after theme_seaborn?

[has2k1]

Sometimes there are weird edge cases that cause plotnine plots to break (although as an important note, resetting your kernel tends to fix them. I have no idea why this happens and I can't faithfully reproduce it), and they arise from complicated layering of plot elements

Any more on this? I do complicated layering without issues.

[darothen]

Hi @has2k1, I do call theme_seaborn before theme in the manner you suggest, and it doesn't resolve the issue. Explicitly setting the plot_background doesn't work either, before or after the call to theme_seaborn. Here is a gist with the original notebook and the data - just change the path in the first cell.

On the layering issue, like I mentioned, I haven't been able to consistently reproduce any issues, but if I stumble across an MWE that works, I'll be sure to post it.

[has2k1]

Sorry I meant 'panel_background'.

[darothen]

Nope, that doesn't fix the legend key background either.

[has2k1]

Ahh I have seen this before. The confidence interval markers for stat_smooth have a default grey background and that is showing up in the legend. Try stat_smooth(se=False).

[darothen]

Aha! That did the trick. Is there a way to clip the way the confidence interval markers are drawn so they don't 100% fill the legend_key box? That way we would have some feedback on how theming is changing that element.

[has2k1]

That is what I immediately thought about.