How to perfectly align an unequal number of plots (ggplot2,gridExtra)

Question

I would like to perfectly align these plots :

Here is the R code :

library(tidyverse)
library(gridExtra)
groupes <- tribble(~type, ~group, ~p         


        

Answer 1

it's probably more manageable if you can set an absolute panel size (and size the device accordingly).

justify <- function(x, hjust="center", vjust="center"){
  w <- sum(x$widths)
  h <- sum(x$heights)
  xj <- switch(hjust,
               center = 0.5,
               left = 0.5*w,
               right=unit(1,"npc") - 0.5*w)
  yj <- switch(vjust,
               center = 0.5,
               bottom = 0.5*h,
               top=unit(1,"npc") - 0.5*h)
  x$vp <- viewport(x=xj, y=yj)
  return(x)
}

library(grid)
gl <- lapply(list(p1,p2,p3),egg::set_panel_size, height=unit(1,"in"))
gl <- lapply(gl, justify, vjust="top")
gridExtra::grid.arrange(grobs=gl, nrow=1)