Relative sizing in compositions

[maayan-amid]

Is it possible to create a composition p1 / p2 where p2 has double the height of p1?

[has2k1]

This is planned for a future release.

[AlFontal]

I was about to raise an issue with a feature request for the same. Glad it's already on the roadplan @has2k1 !

In any case, I am having so much fun with compositions, I have been wanting them working natively in plotnine for so long I am incredibly happy to finally see them here 🥹

As for a rather hacky solution for this use case, @maayan-amid, I am currently doing the following. It isn't perfect but it works if you ignore the leftover whitespaces (which you can always crop in post-processing anyway).

Basically, what I do is generate a nested composition, where p1 and p2 are two different sub-compositions. I create a third empty placeholder plot ph which I then add to the p2 sub-composition as many times as I want the p1:p2 ratio to be.

For a minimal example:

p1 = (p9.ggplot(huron, p9.aes("year", "level"))
    + p9.geom_line())

p2 = (p9.ggplot(huron, p9.aes("factor(decade)", "level"))
    + p9.geom_boxplot()
    + p9.labs(x="decade"))

ph = p9.ggplot() + p9.theme_void()

You can then basically compose p2 and ph as you wish to get the desired size.

For a 2:1 ratio:

subcomp = p2 / ph

p1 / subcomp

for a 3:1 ratio:

subcomp = p2 / ph / ph

p1 / subcomp

And so on. You can also use plot_spacer for this, but somehow what I've found is that whenever the plot_spacer element is the last of the composition it makes it impossible to override the default theme, so that's why I create the placeholder plot to make it work. (#960 seems relevant, although I suspect the issue also applies to other themeables like dpi and not only figure_size)

Hope it's somehow helpful!