ggplot_align_axis_line_bar.R

#https://stackoverflow.com/questions/35536289/how-to-get-the-grid-of-2-graphs-with-different-geom-match-with-ggplot2

library(ggplot2)
library(gridExtra)
library(dplyr)
library(tidyr)


pouet <-tibble(decile = seq(1:10),
               pred1 = c(rep(0.5,10)),
                 pred2 = c(0.3, 0.4, 0.5, 0.6, 0.7, 
                           1.3, 1.4, 1.5, 1.6, 1.8),
                obs = c(rep(0.6, 10)),
                exposure = c(1,2,3,4,5,5,4,3,2,1))

plot_data1<- pouet %>% select(decile, pred1, pred2, obs) %>%
  gather(key=key, value=value, pred1, pred2, obs) 

plot1 <- ggplot(data = plot_data1,aes(x=decile, y= value, color= key)) +
  geom_point() +
  geom_line() +
  scale_x_continuous(breaks = seq(1,max(pouet$decile)),
                     limit= range(plot_data1["decile"]) + c(-.5, .5))  +
theme(axis.ticks.x = element_blank(), axis.text.x = element_blank(), axis.title.x = element_blank()) +
  #xlim(range(plot_data1["decile"]) + c(-.5, .5))  + # 0.5 à 10.5..
  theme(plot.margin=unit(c(0,0,0,0),'lines'))
  

plot2 <- ggplot(data = pouet, aes(x= decile, y= exposure)) + 
  geom_bar(position='dodge',stat='identity')  +
  theme(plot.margin=unit(c(0.5,0,0,0),'lines'))+ 
  scale_x_continuous(breaks = seq(1,max(pouet$decile))) 

grobs <- lapply(list(plot1,plot2), FUN=ggplot2::ggplotGrob)
max_widths <- do.call(grid::unit.pmax, lapply(grobs,  function(x) { x$widths }))
num_plots <- length(grobs)
for (i in 1:num_plots) {
  grobs[[i]]$widths <- max_widths
}
grid.arrange(grobs=grobs , ncol=1, layout_matrix = matrix(c(1,2),nrow=2), heights=c(2,1))