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I am having a problem to increase the size and add a label for x axis when I use grid.arrange.

I asked a question here how can I make my data side by side barplot with dots which the answer is sufficient and I accepted it.

At the end of the code, I should glue three parts together like this 

library(gridExtra) 
gg1 <- ggplot_gtable(ggplot_build(g1)) 
gg2 <- ggplot_gtable(ggplot_build(g2)) 
gg.mid <- ggplot_gtable(ggplot_build(g.mid)) 

grid.arrange(gg1,gg.mid,gg2,ncol=3,widths=c(4/9,1/9,4/9))

I want to add a Label for it but I could not find a way to do this. I also searched and I found only one related post Universal x axis label and legend at bottom using grid.arrange

and I tried to assigned my grid.arrangeto a variable and then 

p <- grid.arrange(gg1,gg.mid,gg2,ncol=3,widths=c(4/9,1/9,4/9))
p <- arrangeGrob(p, textGrob("my label", gp=gpar(fontsize=12)))
print(p)

but the problem is not solved. Any idea how to add such a label for it?

Community
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nik
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1 Answers1

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g1 <- g.mid <- g2 <- ggplot()

grid.arrange(g1,g.mid,g2,ncol=3,widths=c(4/9,1/9,4/9), 
             bottom=textGrob("x axis title", gp=gpar(fontsize=22)))

enter image description here

Edit: perhaps the easiest way to control margins is to wrap the grob in a 3x3 gtable,

titleGrob <- function(label, margin=unit(c(b=5, l=0, t=2, r=0), "line"), ..., debug=FALSE){
  library(gtable)
  tg <- textGrob(label, ...)
  w <- grobWidth(tg)
  h <- grobHeight(tg)

  g <- gtable("title",
              widths = unit.c(margin[2], w, margin[4]), 
              heights = unit.c(margin[3], h, margin[1]), respect = FALSE)
  if(debug){
    rg <- rectGrob()
    pos <- expand.grid(x=1:3, y=1:3)[-5,]
    g <- gtable_add_grob(g, list(rg, rg, rg, rg, rg, rg, rg, rg), t=pos$y, l=pos$x)
  }
  gtable_add_grob(g, tg, t=2, l = 2)
}

grid.arrange(g1,g.mid,g2,ncol=3,widths=c(4/9,1/9,4/9),
             bottom=titleGrob("x axis title", gp=gpar(fontsize=22), debug=FALSE))

enter image description here

baptiste
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  • thanks! I liked and accepted your answer. I have one question, do you know how to also change the font and make them bold (the x axis values) ? – nik Dec 28 '16 at 20:00
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    sounds like a different question, but have a look at `axis.text.x` in `?theme` – baptiste Dec 28 '16 at 20:05
  • sure thanks , one more stupid question. is it possible to make distance between the label you created and the figure? – nik Dec 28 '16 at 20:10
  • thanks I already liked your answer so I cannot like it again. but one question. how can I remove those boxes and change the space? when I use your code, I just create the distance but I add those boxes. Sorry if I ask a lot of question – nik Dec 28 '16 at 20:59
  • try changing the margin parameter and setting debug=FALSE – baptiste Dec 28 '16 at 21:23
  • Yes, I know the problem is that if even I set the values so small like `b=0.6, l=0, t=0.6, r=0`it is still giving a box in the figure (as shown above) I am wondering how to get rid of this box ? On the other hand, if I use `vjust ` I can move the label below but it exceed the figure, I am a bit confused now – nik Dec 28 '16 at 21:26
  • I removed my question but my problem remains as i explained above – nik Dec 28 '16 at 23:03
  • i don't understand what's the problem with setting debug=FALSE in the example – baptiste Dec 29 '16 at 00:10
  • I do set the `debug=FALSE`but I get the two boxes. Can you please post the figure without those boxes above ? `grid.arrange(g1,g.mid,g2,ncol=3,widths=c(4/9,1/9,4/9), bottom=titleGrob("x axis title", gp=gpar(fontsize=22), debug=FALSE))` – nik Dec 29 '16 at 07:43