geom_bar() with facet_grid(space="free") with coord_flip()

[mrdanbrooks]

In the code below, I was expecting space="free" to produce a thinner plot for 'b'.

library(ggplot2)
t <- "Group,Response,Freq,pct_freq,disp
none,1,0,0.000000000,a
low,1,5,0.018939394,a
high,1,65,0.250965251,a
none,2,0,0.000000000,a
low,2,15,0.056818182,a
high,2,89,0.343629344,a
none,3,1,0.007936508,a
low,3,83,0.314393939,a
high,3,73,0.281853282,a
none,4,14,0.111111111,b
low,4,40,0.151515152,b
high,4,14,0.054054054,b
none,5,21,0.166666667,a
low,5,32,0.121212121,a
high,5,14,0.054054054,a
none,6,55,0.436507937,a
low,6,60,0.227272727,a
high,6,4,0.015444015,a
none,7,35,0.277777778,a
low,7,29,0.109848485,a
high,7,0,0.000000000,a"
m <- read.csv(textConnection(t))
m$Response <- factor(m$Response, levels=1:7, ordered=TRUE)
ggplot() + 
    aes(x=Group, fill=Response, order=Response) + 
    geom_bar(data=m, aes(y=pct_freq), position="stack", stat="identity") + 
    facet_grid(. ~ disp, space="free") + 
    coord_flip())

It has been pointed out to me that the most likely reason it behaves like this is that without the coord_flip(), the plots are the same height and this property is being kept. If this is actually the "expected behavior" rather then a bug, it might be useful to add a geom_bar_horiz.

In trying to help me find a work around, @mattantaliss sent me the following code based on the accepted answer to http://stackoverflow.com/questions/12560858/using-coord-flip-with-facet-wrapscales-free-y-in-ggplot2-seems-to-give-u
This makes the size of 'b' behave the way I was expecting, but has a side effect of messing up the bars in 'a', and also requires scales="free" to be set (which I don't want).

library(ggplot2)
library(proto)

geom_bar_horz <- function (mapping = NULL, data = NULL, stat = "bin", position = "stack", ...) {
  GeomBar_horz$new(mapping = mapping, data = data, stat = stat, position = position, ...)
}

GeomBar_horz <- proto(ggplot2:::Geom, {
  objname <- "bar_horz"

  default_stat <- function(.) StatBin
  default_pos <- function(.) PositionStack
  default_aes <- function(.) aes(colour=NA, fill="grey20", size=0.5, linetype=1, weight = 1, alpha = NA)

  required_aes <- c("y")

  reparameterise <- function(., df, params) {
    df$width <- df$width %||%
      params$width %||% (resolution(df$x, FALSE) * 0.9)
    OUT <- transform(df,
                     xmin = pmin(x, 0), xmax = pmax(x, 0),
                     ymin = y - .45, ymax = y + .45, width = NULL
    )
    return(OUT)
  }

  draw_groups <- function(., data, scales, coordinates, ...) {
    GeomRect$draw_groups(data, scales, coordinates, ...)
  }
  guide_geom <- function(.) "polygon"
})

t <- "Group,Response,Freq,pct_freq,disp
none,1,0,0.000000000,a
low,1,5,0.018939394,a
high,1,65,0.250965251,a
none,2,0,0.000000000,a
low,2,15,0.056818182,a
high,2,89,0.343629344,a
none,3,1,0.007936508,a
low,3,83,0.314393939,a
high,3,73,0.281853282,a
none,4,14,0.111111111,b
low,4,40,0.151515152,b
high,4,14,0.054054054,b
none,5,21,0.166666667,a
low,5,32,0.121212121,a
high,5,14,0.054054054,a
none,6,55,0.436507937,a
low,6,60,0.227272727,a
high,6,4,0.015444015,a
none,7,35,0.277777778,a
low,7,29,0.109848485,a
high,7,0,0.000000000,a"

m <- read.csv(textConnection(t))
m$Response <- factor(m$Response, levels=1:7, ordered=TRUE)

print(ggplot(data = m, 
       aes(y = Group, x = pct_freq, fill = Response, order = Response)) + 
  geom_bar_horz(position = "identity", stat = "identity") + 
  facet_grid(. ~ disp, scales = "free", space = "free"))

I am using

• ggplot2 1.0.1
• R 3.2.1
• OSX 10.7.5

[hadley]

Yeah, unfortunately free scales don't interact well with different coordinate systems.