Feature request: allow inset_element() to handle facet merging

[matiasandina]

I am trying to plot a facet plot. My idea is to display inset plots according to the facet. Here's a reproducible example using mtcars. The idea would be to get density plots for am=0 on the proper (am=0) facet at (0.5, 0.5, 1, 1). Same idea for am=1.

library(tidyverse)
library(patchwork)
p1 <- ggplot(mtcars, aes(cyl, mpg)) + 
  geom_point(color = "red") +
  facet_wrap(~am)
p2 <- ggplot(mtcars, aes(hp)) + 
  geom_density(aes(fill=factor(cyl), color=factor(cyl))) +
  facet_wrap(~am)
p1

p2

I understand why this is not functioning the way I want it. I am not sure if this should be an acceptable feature request to the library. Ideally, patchwork would automagically realize that the inset has to go on proper panels.

p1 + inset_element(p2, 0.5, 0.5, 1, 1)

^{Created on 2023-12-11 with reprex v2.0.2}

The expected output would be:

I came up with a solution to individually subset data and return the inset plot to be later used in a layout. I have also asked this question and there is a proposed answer that is a bit more elegant than my method here. I feel that this use case is a somewhat complex functionality that people end up having to customize like here. It would be great if patchwork could handle this internally.

[thomasp85]

I understand the wish for something like this but it will not happen for multitudes of technical reasons :-)

The way forward is to subset the data manually as you've already arrived at